FR2965358A1 - Use of at least one amino acid sequence encoded by a nucleic acid sequence or of nucleic acid sequence, as a biomarker of a state of aged skin and/or signs of aging, optionally associated with dry skin - Google Patents

Abstract

Use (i) of at least one amino acid sequence encoded by a nucleic acid sequence represented by SEQ ID NO: 1 (comprising a fully defined 333 amino acid sequence as given in the specification) or its an analogue or a fragment, or (ii) of nucleic acid sequence, as a biomarker of a state of aged skin and/or signs of aging, optionally associated with dry skin, is claimed. Independent claims are included for: (1) use of at least one amino acid sequence comprising SEQ ID NO: 12-20 (one of 9 fully defined 11-121 amino acid sequences (SEQ ID NO: 12-20) as given in the specification) or its analog with a sequence identity of at least 90% with the sequence and a biological activity of the same nature, or its fragment which comprises 3-48 amino acids of the sequence and which has a biological activity of the same nature, or at least one the nucleic acid sequence for screening active agents or physical treatments, which may modulate the activity, expression or maturation of the amino acid sequence or the nucleic acid sequence; (2) use of (i), (ii) or at least one agent modulating the activity, expression or maturation of the amino acid sequence or the nucleic acid sequence to prepare a multilayered epithelial cell model, preferably a reconstructed skin model; (3) a process of in vitro or ex vivo process to characterize a state of aged skin and/or signs of skin aging, optionally associated with dry skin comprising: carrying out, in a sample isolated from a skin, a measurement of qualitative or quantitative expression, maturation or activity of the amino acid sequence or of the nucleic acid sequence and comparing the measurement made in the step (a) to a reference measurement; (4) a process of in vitro or ex vivo screening of active agents or for physical treatment, which may modulate the activity, expression or maturation of the amino acid sequence comprising SEQ ID NO: 12-20 or the nucleic acid sequence comprising: placing the amino acid sequence or the nucleic acid sequence under conditions favorable to the activity, expression or maturation of the sequences; contacting the amino acid sequence or the nucleic acid sequence with at least one active agent to be tested, or exposing the amino acid sequence or nucleic acid sequence with a physical treatment to be tested; carrying out a qualitative or quantitative measurement of the expression, maturation or the activity of the amino acid sequence or the nucleic acid sequence; and comparing the measurement to a reference measurement; (5) a cosmetic process for preventing and/or treating an aged skin and/or signs of skin aging, optionally associated with skin dryness, comprising administering, to the individual, at least one composition comprising as active agent (i) or (ii); (6) a process for in vitro or ex vivo cosmetic process, to characterize the effectiveness of a cosmetic skin treatment in an individual, comprising: carrying out, before the implementation of cosmetic treatment, in a first isolated skin sample taken from the individual, isolated, at least a first qualitative or quantitative measurement of the expression, maturation or activity of at least one amino acid sequence or at least one nucleic acid sequence; carrying out, after the implementation of the cosmetic treatment, in isolated second skin sample taken from the individual, at least a second qualitative or quantitative measurement of the expression, maturation or activity of the amino acid sequence or the nucleic acid sequence, and comparing the first and second measures, preferably in order to deduce information relating to an effect of implementation of the cosmetic treatment; (7) a isolated peptide represented by a sequence of amino acid SEQ ID NO: 18 (comprising a fully defined a fully defined 29 amino acid sequence as given in the specification) or its analogue or its fragment; and (8) a cosmetic composition comprising a peptide or a nucleic acid sequence encoding the peptide. ACTIVITY : Dermatological; Antipruritic. MECHANISM OF ACTION : None given.

Description

The present invention relates to the field of biomarkers of the skin, and more particularly of dry skin, and to their use as targets or cosmetic active agents. The epidermis, the superficial part of the skin, is a tissue whose cells are contiguous and integral with one another and rest on a basement membrane. It forms an outer coating comprising sebaceous or sweat glands and hair follicles. More specifically, the epidermis is a structure whose homeostasis results from the implementation of a finely regulated set of intracellular and extracellular signals acting at all stages of proliferation, migration, cell differentiation, as well as of the synthesis of the different components of the extracellular matrix. These signals may, in particular, result from the action of factors produced by the keratinocytes. The epidermis is conventionally divided into a basal layer of keratinocytes containing, in particular, cutaneous stem cells and constituting the germinal layer of the epidermis, a so-called spinous layer consisting of several layers of polyhedral cells arranged on the basal layer, a so-called granulosa comprising one to three layers of flattened cells containing distinct cytoplasmic inclusions, keratohyaline grains, and finally, a set of upper layers, called stratum corneum, or corneal layer, consisting of keratinocytes at the end stage of their differentiation, called corneocytes . The stratum corneum, the outermost part of the skin that provides the barrier function between the body and the environment, and the hair shaft, the emergent part of the hair follicle that makes up the hair, are both the culmination of the healing process. differentiation of keratinocytes. Epidermal differentiation follows a maturation process in which basal layer keratinocytes differentiate and migrate to form corneocytes, dead cells that are completely keratinized. This differentiation is the result of perfectly coordinated phenomena that will lead to the maintenance of homeostasis and hydration of the epidermis, and give the skin a healthy, youthful, luminous and smooth appearance. The stratum corneum, because of its solidity and its compact stratified structure, provides a barrier function: it opposes in particular the loss of transcutaneous water, also called "insensible loss of water". Thus, one of the functions of the stratum corneum is to capture and retain the water contained in the epidermis, and any alteration of its structure and / or function may result in changes in skin hydration. Hydration is provided to the skin by deep-layer water and sweat. An imbalance in the hydration of the skin can have profound consequences, both physiological and cosmetic. Skin hydration disorders, including skin dryness, are often observed with age and / or climate change. However, such states may also occur in young subjects.

The state of cutaneous dryness can be of origin acquired or constitutional non-pathological or it can have a pathological constitutional origin. Many external factors can dry the skin or make it worse. These factors include climatic conditions such as cold or wind, sunlight, exposure to certain chemical or therapeutic agents. Physiologically, dry skin is often associated with a decrease in the level of skin hydration and a change in the process of maturation of the stratum corneum with the most visible sign of the appearance of dander on the skin surface. On the sensory level, dry skin can be characterized by a feeling of tightness and / or cutaneous tension. Many epidermal factors, whose expression, biological activity or maturation are altered, diminished or increased, are known to be involved, directly or indirectly, in the occurrence and manifestation of a dryness of the skin or different signs of skin dryness associated.

These factors can be used as bio-markers of dry skin, as screening targets for new skin dryness treatments, or even as cosmetic active agents for skin hydration and skin treatment. dried. However, there are still many unknowns as to the intimate mechanism and all the factors involved in the hydration and dryness of the skin.

Thus, there remains a need to identify new biomarkers of the skin, and in particular dry skin or signs of dry skin. There is also a need for new biomarkers to characterize a state of the skin, and in particular dry skin or signs of dry skin. There is still a need for new tools or targets for the screening of active agents or physical treatments suitable for the care of the skin, and more particularly useful for preventing and / or treating dry skin or signs of dry skin.

There is still a need for new tools or targets for the screening of active agents or physical treatments to promote or enhance the hydration of the skin. There is still a need for new actives or treatments to promote and / or enhance the hydration of the skin.

There is still a need for new assets or treatments for the prevention and / or treatment of dry skin or signs of skin dryness. There is still a need for new cosmetic targets for the care of the skin, in particular to promote and / or enhance the hydration of the skin and in particular for the prevention and / or treatment of dry skin or signs of skin. cutaneous dryness. The object of the present invention is to satisfy these needs. Thus, according to one of its first objects, the present invention relates to the use (i) of at least one amino acid sequence encoded by a nucleic acid sequence represented by SEQ ID NO: 1, an analogue or a fragment of said amino acid sequence, or (ii) of said nucleic acid sequence, as a biomarker of a state of hydration of the skin, and in particular of dry skin and / or signs of dry skin. For the purposes of the invention, the term "biomarker" means a molecule or the activity of a molecule, the presence, content or degree of activity of which is characteristic of a biological, physiological or pathological process, or the impact or effect of administering an active agent or physical treatment on such a process. For the purposes of the invention, the term "skin" refers to the entire epidermis of a human body, including the scalp and lips. More particularly, the skin considered in the present invention is preferably the lips, the skin of the face, décolleté, arms or legs, and preferably the skin of the face and / or décolleté. Unexpectedly, in a Western blot comparative proteomics study, the inventors observed from proteins extracted from varnished strippings from populations with different degrees of skin hydration that Dermcidin (or DCD) was found to be a biomarker. sensitive and specific to dry skin. More specifically, the inventors have observed that the level of expression of Dermcidine, and more particularly of a peptide identified by the sequence SEQ ID NO: 14 was systematically decreased in dry skin compared to the normally hydrated skin. To the inventors' knowledge, this cutaneous surface antimicrobial protein has never been classified as varying during dryness of the skin and even less as one of the most relevant biomarkers emerging from this type of study. Dermcidin is known to be a sudoriparous protein (Schittek, Hipfel et al., 2001), but skin dryness is a complex phenomenon that is not systematically associated with a sudoriparous deficit. On the other hand, the experimental data obtained by the inventors show, surprisingly and unexpectedly, that there is a specific deficit in net expression and / or excessive maturation of DCD in cutaneous dryness.

According to yet another of its objects, the present invention relates to the use (i) of at least one amino acid sequence of the invention, or (ii) a nucleic acid sequence of the invention, for screening active agents or physical treatments capable of modulating the activity, expression or maturation of said amino acid sequence or said nucleic acid sequence and intended to promote and / or enhance the hydration of the skin. Preferably, such active agents or physical treatments may be intended to prevent and / or treat dry skin and / or signs of dry skin.

For the purposes of the invention, the term "expression" with respect to an amino acid sequence, for example a protein or a peptide, or a nucleic acid sequence, for example an mRNA, its content or the variation of its content with respect to a reference.

For the purposes of the invention, the term "maturation" with respect to an amino acid sequence, for example a protein or a peptide, or a nucleic acid sequence, for example an mRNA, the modifications who follow their synthesis in a cellular environment. For example, in the case of an amino acid sequence, "maturation" is understood to mean post-translational modifications, such as the glycosylation or the farnesylation of certain amino acids, or the proteolytic steps leading to the elimination of sequences. so-called "signal" or "secretory" or the release of sequences with particular biological properties. In the case of a nucleic acid sequence, the term "maturation" is understood to mean, for example, the alternative splicing of an mRNA. Within the meaning of the invention, the term "activity", with respect to an amino acid sequence, for example a protein or a peptide, the biological activity of the amino acid sequence, where appropriate after maturation, such as enzymatic activity, receptor agonist or antagonist activity, or enzyme activator or inhibitor, so-called "structure" activity, or antimicrobial activity.

Within the meaning of the invention, the term "activity" refers to a nucleic acid sequence, for example an mRNA, its translation. According to another of its objects, the present invention relates to the use (i) of at least one amino acid sequence of the invention, or (ii) at least one nucleic acid sequence of the invention , to characterize the effectiveness of a cosmetic treatment of dry skin and / or signs of dry skin. According to yet another of its objects, the present invention relates to the cosmetic use of an effective amount (i) of at least one amino acid sequence of the invention, or (ii) at least one sequence of nucleic acids of the invention, or (iii) at least one agent modulating the activity, expression or maturation of said amino acid sequence or said nucleic acid sequence, active agent to promote and / or enhance the hydration of the skin.

Preferably, a use of the invention may be dedicated to preventing and / or treating dry skin and / or signs of cutaneous dryness. Within the meaning of the present invention, the term "effective amount" of a compound of the invention, a sufficient and necessary amount of this compound to obtain a desired effect, and more particularly a cosmetic effect or care with regard to hydration of the skin, and in particular of dry skin and / or signs of cutaneous dryness. Within the meaning of the invention, the term "prevent" means reducing the risk of occurrence or slowing down the occurrence of a given phenomenon, namely in the present invention, dry skin and / or signs of cutaneous dryness. According to yet another of its objects, the present invention relates to a method for characterizing a state of hydration of the skin, and in particular dry skin and / or cutaneous signs of drought, comprising at least the steps of: a) performing, in an isolated sample of a skin, a qualitative or quantitative measure of the expression, the maturation or the activity of said amino acid sequence or said nucleic acid sequence, and b) compare said measurement carried out in step a) to a reference measurement. Depending on the difference observed between the measurement obtained and the reference measurement, the skin will be described as normally hydrated skin or dry skin. According to yet another of its objects, the present invention relates to a method for screening active agents or physical treatments capable of modulating the activity, expression or maturation of an amino acid sequence of the invention. or a nucleic acid sequence of the invention for promoting and / or enhancing the hydration of dry skin, comprising at least the steps of: a) disposing of said amino acid sequence or said sequence nucleic acid under conditions conducive to the activity, expression or maturation of said sequences, b) contacting said amino acid sequence or said nucleic acid sequence with at least one active agent to be tested, or exposing said amino acid sequence or said nucleic acid sequence with a physical treatment to be tested; c) performing a qualitative or quantitative measurement of the expression, maturation or activity of said nucleic acid sequence; quence of amino acids or said nucleic acid sequence; and d) comparing said measurement with a reference measurement.

Depending on the difference observed between the measurement obtained and the reference measurement, the compound or the physical treatment screened will be characterized or not as being useful for promoting and / or enhancing the hydration of the skin. According to a preferred embodiment, active agents that promote and / or enhance the hydration of the skin may be used for the prevention and / or treatment of dry skin.

According to a preferred embodiment, a method or a use in accordance with the invention may be carried out in vivo, in vitro, or ex vivo, and even more preferably in vitro or ex vivo. The present invention has the advantage of providing a new biomarker sensitive and specific to the hydration of the skin, and in particular dry skin or signs of dry skin. The observation of the presence of Dermcidin in the stratum corneum advantageously makes possible a quantitative or qualitative determination of the expression or the activity of this protein, or the corresponding peptides, by simple topical sampling.

The sampling method may for example be a stripping type of technique to apply to the epidermis considered a portion of adhesive tape. By peeling off this tape, a fraction of the surface of the skin is removed. After protein extraction, this can then be analyzed by conventional methods, such as the enzyme immunoassay ELISA or the differential proteomic method iTRAQ, or more particularly by Western-Biot analysis as defined below. Also, the present invention has the advantage of being able to provide a new biomarker suitable for screening new active agents or new physical treatments useful for promoting and / or enhancing the hydration of the skin. Preferably, such agents or treatment may be suitable for preventing and / or treating dry skin and / or signs of dry skin.

Also, according to another advantage, the present invention makes it possible to propose new active agents that are useful for promoting and / or enhancing the hydration of the skin. Preferably, such agents or treatment may be suitable for the prevention and / or treatment of dry skin and / or signs of dry skin.

Amino Acid and Nucleic Acid Sequences Dermcidine or Preproteolysin (DCD) is a 110 amino acid protein (SEQ ID NO: 9) having a 19 amino acid signal peptide (SEQ ID NO: 12) whose gene is located on chromosome 12, locus 12813.1. Two isoforms of this protein are identified, one shorter, isoform 1 (SEQ ID NO: 8), the other longer, isoform 2 (SEQ ID NO: 9). It is secreted in sweat (Schittek, Hipfel et al., 2001). After cleavage of the signal peptide, Dermcidine (DCD) is a protein of 90 amino acids according to the sequence SEQ ID NO: 14. After a proteolytic post-translational processing, essentially by Cathepsin D, which takes place in sweat (Baechle, Flad et al., 2006), this protein precursor gives rise to DCD-1 (SEQ ID NO: 15) and DCD-1L (SEQ ID NO: 16) as well as to many peptides whose length varies from 25 to 48 aa (Flad, Bogumil et al., 2002). Unless otherwise indicated, the term "Dermcidin" is intended to mean in this application the amino acid sequences represented by SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 14, SEQ ID NO: 15 and SEQ ID NO: 16, whether or not undergoing post-translational processing. According to a preferred embodiment, Dermcidine is more particularly referred to as the amino acid sequence represented by SEQ ID NO: 14.

Among the peptides derived from the maturation of Dermcidin, as described in US 2008/020976, some show antimicrobial activities against various microorganisms, such as Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, or Candida albicans. The antimicrobial peptides are derived from the C-terminal portion of the protein.

The N-terminal portion of the protein (SEQ ID NO: 13) consists of a biologically active factor promoting cell survival (Cunningham, Hodge et al., 1998).

This protein is constitutively expressed in the sweat gland (Rieg, Garb et al., 2004), and is implicated in particularly important PI3K / AKT / mTOR signaling pathways in cell proliferation and survival (Moreira, Strauss et al., 2008). The decrease in DCD observed in the sweat of individuals with atopy could partly explain their microbial susceptibility (Rieg, Steffen et al., 2005). Some of the antimicrobial and N-terminal fragments are capable of stimulating the production of cytokines / chemokines by keratinocytes or other cell types involved in the regulation of cutaneous immunity (Watchorn, Dowidar et al., 2005). Niyonsaba, Suzuki et al., 2009). The use of DCD has recently been proposed as a particularly sensitive specific marker for the presence of sweat traces by RT-PCR or ELISA for use in the forensic field (Sakurada, Akutsu et al., 2009).

According to one embodiment, an amino acid sequence suitable for the invention may be encoded by a nucleic acid sequence represented by SEQ ID NO: 1, or be an analogue or a fragment of this amino acid sequence. By "analogue of an amino acid sequence" according to the invention is meant any amino acid sequence having a sequence identity of at least 85%, preferably at least 90%, and more. preferably at least 95% with said sequence, and a biological activity of the same nature. By "biological activity of the same nature" with respect to an amino acid sequence according to the invention is meant the antimicrobial or stimulation properties of the survival and / or cell proliferation usually attributed to Dermcidin.

Sequence identity can be determined by visual comparison or by any computer tool commonly used in the domain, such as BLAST programs available at www.ncbi.nlm.nih.gov and used with default settings. An analogue according to the invention may be a peptidomimetic agent.

An analogue of an amino acid sequence of the invention may result from modifications resulting from mutation or variation in the sequences of the peptides according to the invention either from the deletion or from the insertion of one or more amino acids either the substitution of one or more amino acids or alternatively splicing. Many of these changes can be combined. Advantageously, an analogue of an amino acid sequence of the invention may comprise conservative substitutions with respect to this amino acid sequence. By way of example of mutations which may be considered in the present invention, it may be mentioned, in a non-exhaustive manner, the replacement of one or more amino acid residues by amino acid residues having a subscript. similar hydropathic without substantially affecting the biological properties of the polypeptide. The hydropathic index is an index attributed to amino acids as a function of their hydrophobicity and charge (Kyte et al (1982) J. Mol Biol., 157: 105). An amino acid sequence or an analogue thereof targeted by the present invention may be an amino acid sequence having undergone one or more post-translational processing (s). By "post-translational processing (s)" is intended to encompass all the modifications that an amino acid sequence is likely to undergo at the end of its synthesis in a cell, such as, for example, a or phosphorylation (s), thiolation (s), acetylation (s), glycosylation (s), lipidation (s), such as farnesylation or palmitoylation, rearrangement Disulfide-type and / or cleavage-type structural bonding within the peptide sequence. An analogue of an amino acid sequence has, moreover, substantially the same biological activity as this amino acid sequence.

It is moreover known that a primary amino acid sequence may comprise sites specifically recognized by protease-type enzymes, such as trypsin, which, once the recognition of these effective sites will induce the cleavage of the sequence by proteolysis. This proteolysis results in the generation of various peptides, or fragments of amino acid sequences of the invention.

Consequently, the invention also extends to fragments of Dermcidin, possibly resulting from its proteolysis.

Within the meaning of the invention, the term "fragment of an amino acid sequence" means any portion of the amino acid sequence according to the invention comprising from 3 to 48 consecutive amino acids of said sequence, preferably from 6 to 36, preferably 8 to 32, and more preferably 10 to 30 consecutive amino acids of said sequence, and has a biological activity of the same kind. According to one embodiment, an amino acid sequence that is suitable for the invention may be an amino acid sequence represented by a sequence chosen from SEQ ID NO: 9 to 16, in particular from SEQ ID NO: 9, SEQ ID NO : 10, SEQ ID NO: 11, an analogue, or a fragment thereof, According to a preferred embodiment, an amino acid sequence suitable for the invention may be an amino acid sequence represented by a sequence selected from SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, an analogue, or a fragment thereof. Still more preferably, an amino acid sequence suitable for the invention may be an amino acid sequence represented by a sequence chosen from SEQ ID NO: 14, SEQ ID NO: 15 or SEQ ID NO: 16, an analogue or a fragment thereof. Preferably, an amino acid sequence suitable for the invention may be an amino acid sequence represented by a sequence selected from SEQ ID NO: 14, an analogue or a fragment thereof. According to another embodiment, a polypeptide that is suitable for the invention may also be a natural or synthetic amino acid sequence, which may optionally be obtained after enzymatic or chemical lysis of Dermcidine or by chemical or biological synthesis, or by extraction from a biological tissue, such as for example the skin, naturally expressing this amino acid sequence or after transfection thereof, as well as the various post-translational forms thereof, or any sequence of natural or synthetic amino acids whose sequence completely or partially comprises a aforementioned amino acid sequence, for example variants and analogs. Those skilled in the art can obtain an amino acid sequence according to the invention by means of recombinant DNA methods, such as, for example, those described in the manual "Molecular Cloning - A Laboratory Manual" ( 2nd edition), Sambrook et al., 1989, Vol. I-III, Coldspring Harbor Laboratory, Coldspring Harbor Press, NY, (Sambrook). According to another embodiment, an amino acid sequence that is suitable for the invention may also be an amino acid sequence as defined above, fused with another amino acid sequence, a hydrophilic or hydrophobic targeting agent, a bio-conversion precursor, a luminescent, radioactive or colorimetric labeling agent. Without limitation, examples of compounds that may be coupled to an amino acid sequence according to the invention include fluorescent proteins such as "Green Fluorescent Protein", fluorescent chemical compounds, such as rhodamine, fluorescein, or Texas Red®, phosphorescent compounds, radioactive elements, such as 3H 14C 35S 1211 or 125I, or colorimetric labeling agents such as chromogenic substrates sensitive to the action of galactosidase, peroxidase, chloramphenicol acetyltransferase, luciferase or alkaline phosphatase. Depending on the nature of the compounds capable of being coupled with an amino acid sequence of the invention, the coupling may be carried out by chemical methods, in particular by means of reactive chemical functions or by molecular biological methods known to the art. skilled in the art.

Advantageously, an amino acid sequence of the invention may be encoded by a nucleic acid sequence selected from a sequence represented by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, an analogue or fragment thereof.

According to one embodiment, the present invention also relates to nucleic acid sequences coding for an amino acid sequence of the invention and their use in the various uses and processes according to the invention. Thus, the present invention also relates to a nucleic acid sequence, in particular of deoxyribonucleic acids, or of ribonucleic acids, represented by SEQ ID NO: 1, an analogue or a fragment thereof. For the purposes of the present invention, the term "nucleic acid sequence fragment" means a nucleic acid sequence comprising from 9 to 144 consecutive base pairs of said sequence, preferably from 18 to 108, preferably 24 to 96, and more preferably from 30 to 90 consecutive base pairs of said sequence, and encoding an amino acid sequence having a biological activity of the same nature as the amino acid sequence encoded by said sequence.

For the purposes of the present invention, the term "nucleic acid sequence analogue" means a nucleic acid sequence having a sequence identity of at least 85%, preferably at least 90%, and more. preferably at least 95% with said sequence, and coding for an amino acid sequence having a biological activity of the same nature as the amino acid sequence encoded by said sequence.

By "analog of a nucleic acid sequence" is meant a nucleic acid sequence, possibly resulting from the degeneracy of the nucleic acid code, and coding for an amino acid sequence according to the invention, in particular as defined above. According to a preferred embodiment, a nucleic acid sequence of the invention may be represented by a sequence chosen from SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ. ID NO: 6, SEQ ID NO: 7 and SEQ ID NO: 8, an analogue or fragment thereof. A nucleic acid sequence of the invention may be of any possible origin, namely either animal, in particular mammalian and even more particularly human, either plant, or micro-organisms, such as for example viruses, phages, or bacteria, among others, or fungi, without prejudging the fact that they are naturally present or not in said original organism. According to one embodiment, the invention also relates to the isolated and purified nucleic acid sequences coding for an amino acid sequence considered according to the invention, as well as to their analogs and fragments. A nucleic acid sequence according to the invention may comprise a sense, antisense or interferential sequence corresponding to a sequence coding for a polypeptide according to the invention. The subject of the invention is also nucleic acid sequences, in particular of ribonucleic or deoxyribonucleic acids, comprising a sense or antisense sequence, in particular "small interferent RNA" (siRNA), corresponding at least to a sequence coding for a polypeptide of the invention or a nucleic acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, an analogue or a fragment thereof.

Hydration of the skin - dry skin and signs of skin dryness "Skin hydration" is understood to mean all the cellular and molecular mechanisms that lead to ensuring and maintaining the presence of a quantity of physiological water in the skin. epidermis and dermis, as well as the resulting amount of water.

According to one aspect, the invention aims to maintain or even stimulate the homeostasis of these mechanisms, and thus to promote and / or enhance the hydration of the skin. Thus, in one aspect, the invention is directed to skins having a physiological hydrated state, also known as normal. According to another aspect, the invention aims at restoring the equilibrium or at reducing the risk of occurrence of an imbalance in the homeostasis of these mechanisms, and thus preventing and / or treating dry skin and / or signs of cutaneous dryness. By "dry skin" is meant a general condition of the skin resulting from a water deficiency of the epidermis and / or dermis. By "signs of skin dryness" is meant any changes in the appearance of the skin due to water deficiency in the epidermis and / or dermis. Depending on the degree of manifestation of water deficit in the skin, dry skin may appear rough to the touch, wrinkled or even covered with scales. Dry skin can be manifested, for the most part, by a feeling of tightness and / or tension. Dry skin may manifest as a desquamation disorder and exhibit different stages depending on the severity of this desquamation. When the skin is slightly dry, these scales are abundant but not very visible to the naked eye, elimination corneocyte corneocyte. They are fewer in number but more and more visible to the naked eye when this disorder worsens, the clusters may include several hundred corneocytes, thus representing more or less large clusters, called dander.

Cutaneous dryness can be constitutional or acquired.

In the case of constitutional dry skin, two categories can be distinguished: pathological skin and non-pathological skin.

The constitutional dry pathological skins are essentially represented by atopic dermatitis and ichthyoses. They are almost independent of external conditions and originate from known or unknown genetic modifications. Known genetic modifications affecting cutaneous hydration include, for example, modifications of the Transglutaminase-1 gene or those of the Filaggrin gene.

According to one embodiment, the present invention relates to a pharmaceutical or dermatological composition comprising in a physiologically acceptable medium an effective amount (i) of at least one amino acid sequence of the invention, or (ii) at least one a nucleic acid sequence of the invention, or (iii) at least one agent modulating the activity, expression or maturation of said amino acid sequence or said nucleic acid sequence as an active agent for preventing and / or treating pathological constitutional dry skin selected from atopic dermatitis and ichthyosis.

In the case of non-pathological constitutional dry skin, the severity of the drought condition may, in turn, depend on external factors. Included in this skin category are senile skin (characterized by a general decrease in cutaneous metabolism with age), fragile skin (very sensitive to external factors and often accompanied by erythema and rosacea) and vulvar xerosis (d probable genetic origin and manifesting itself primarily on the face, limbs and back of the hands).

In the case of acquired dry skin, the intervention of external parameters such as exposure to chemical agents, difficult climatic conditions, solar rays or even certain therapeutic treatments (retinoids, for example) is crucial. Under these external influences, the epidermis can then become momentarily and locally dry. This can affect any type of epidermis.

Regardless of the origin, a skin with dryness of the skin may present, generally, the following signs: roughness to the touch and scaly, as well as reduced flexibility and elasticity.

Dry skin, also called "xerosis", can appear at any age, and not be linked to a pathological condition. We will speak in this case of "acquired" drought. However, xerosis becomes more common and troublesome with age, especially in women. This is called senile xerosis. In addition, women usually experience a worsening of skin dryness during menopause, probably due to the hormonal imbalance characteristic of this phenomenon. The most affected areas are the lower legs, the dorsal forearm and the hands.

As mentioned earlier, acquired drought can be influenced by external factors. For example, the appearance of dry skin can be promoted by cold, dry, and wintry weather. We are talking about winter xerosis. Skin dryness can also be induced by exogenous stress, of chemical origin, for example of the anionic detergent type, or else of mechanical origin (friction, shaving).

According to one embodiment, a cosmetic use of the invention may advantageously be suitable for preventing and / or treating senile or fragile dry skin, or xerosis, in particular chosen from xerosis vulgaris, senile xerosis, and winter xerosis. According to one embodiment, a dry skin considered in the invention may be in particular a young skin. Although no studies have shown that dryness has an impact on the origin and formation of fine lines and wrinkles that are mainly due to aging, on the visual side dry skin makes them more noticeable. Dry skin can therefore be young or aged skin with wrinkles or fine lines. Wrinkles and fine lines resulting from cutaneous dryness are therefore not associated with skin aging. In addition, on the sensory level, skin dryness is characterized by a feeling of tightness and / or itching. For obvious reasons, these manifestations are not only a source of discomfort, even pain, but also of an unsightly appearance.

According to one embodiment, a cosmetic use of the invention may advantageously be suitable to prevent and / or treat feelings of tightness and / or itching associated with dry skin. By way of example of signs of cutaneous dryness considered in the invention, mention may be made of skin that is withered, lack of elasticity, suppleness and / or tone of the skin, rough touch, the presence of crevices, desquamation, the presence of scales, or wrinkles and fine lines associated with dry skin. The signs of cutaneous dryness considered are also all internal changes in the skin that do not always result in a modified external appearance, such as, for example, all internal skin damage, and more particularly the degradation of elastin fibers, or elastic fibers, following drying of the dermis.

Biomarker The present invention relates to the use of at least one amino acid sequence of the invention, or at least one nucleic acid sequence of the invention, as a biomarker of a hydration state. skin, and more particularly dry skin and / or signs of skin dryness. According to one embodiment, a decrease in the activity, expression or maturation of said biomarker may be indicative of a skin deficient in hydration, and more particularly of a dry skin and / or signs of cutaneous dryness. The present invention relates, in another of its aspects, to the use of at least one amino acid sequence of the invention, or at least one nucleic acid sequence of the invention, to characterize the effectiveness of a cosmetic treatment of dry skin and / or signs of skin dryness. According to one embodiment, an increase in the activity, the expression or the maturation of said biomarker may be indicative of an effective cosmetic treatment to exert a beneficial effect on the skin in the absence of hydration, and more preferentially a effect on dry skin and / or signs of skin dryness.

In a use according to the invention, a decrease or an increase of the activity, the expression or the maturation of said biomarker can be determined by comparison with a reference measurement obtained according to any method known to man of the 'art.

A "reference measurement" for a given parameter, is a qualitative or quantitative measure of this parameter carried out under so-called "control" or "normal" conditions, for example determined in a reference sample, or determined in a sample in the absence of a treatment alleged to have an effect on the parameter. For example, a reference measurement for an amino acid sequence or a nucleic acid sequence according to the invention may be a quantitative or qualitative value relating to the expression, the maturation or the activity of said sequences determined in a skin sample young, physiologically healthy and normally hydrated, or determined in a sample of dry skin, before a cosmetic treatment.

Preferably, a reference measurement is a statistical measurement, that is to say having been repeated on different samples so as to obtain an average. The reference measurement can be performed in parallel or sequentially with the test measurement. It can also be a "historical" measure, that is to say done prior to the test measurement, and stored, for example in a database, for later use. A comparison of the test measurement with a reference measurement, and an observation of a deviation or no deviation between the two measurements, makes it possible to derive information as to the measured parameter, for example the decrease or the increase. the expression, the processing or the activity of an amino acid sequence or a nucleic acid sequence according to the invention. Such information may subsequently be used to determine the normally hydrated or dry nature of a skin. A method according to the invention may also be performed on a skin sample taken from an epidermal cell model, or a reconstructed isolated skin to qualify the condition.

According to one embodiment, the invention relates to a method, in particular in vitro or ex vivo, for characterizing a state of hydration of the skin. A method of the invention advantageously allows to characterize a dry state of the skin and / or signs of dry skin.

According to another embodiment, the invention relates to a cosmetic or non-therapeutic method, in particular in vitro or ex vivo, for characterizing the effectiveness of a cosmetic treatment of dry skin and / or signs of cutaneous dryness, in an individual in need, comprising at least the steps of: a) performing, before carrying out the cosmetic treatment, in a first isolated skin sample taken from said individual, at least a first qualitative or quantitative measure of the expression, maturation or activity of an amino acid sequence of the invention or a nucleic acid sequence of the invention, b) performing, after the cosmetic treatment is carried out, in a second isolated skin sample taken from said individual, at least a second, qualitative or quantitative measure of the expression, the maturation or the activity of said amino acid sequence of the invention or of said nucleic acid sequence of the invention, and c) comparing the first and second measurements, in particular in order to deduce information relating to an effect at least from the implementation of the cosmetic treatment.

It goes without saying that the measurements made in steps a) and b) must be comparable to one another, and therefore be relative to the same parameter. Preferably, a method of the invention makes it possible to demonstrate an effect of a cosmetic treatment that can make the dry skin and / or the signs of dryness of the skin regress.

The qualitative or quantitative measurement of the expression, the maturation or the activity of a nucleic acid sequence of the invention can be determined by any method known to those skilled in the art. By way of example of methods that are suitable for the invention, mention may be made of the polymerase chain reaction (PCR), quantitative (Q-PCR) or not, in the presence or absence of reverse transcriptase (RT-PCR or Q-RT-PCR), Northern-blot, ribonuclease protection assay, microarray methods, transcriptomic chip methods, oligonucleotide microarray methods, hybridization methods if you. By way of example of agents suitable for the detection of a nucleic acid sequence of the invention, and in particular of an mRNA sequence, mention may be made of labeled nucleic acid probes which can be hybridizing to a nucleic acid sequence of the invention. Such a nucleic acid probe can be easily obtained by any method known to those skilled in the art. Thus, the nucleic acid sequences according to the invention can be used to produce sense and / or antisense oligonucleotide primers, which hybridize under conditions of high stringency to at least one of the sequences SEQ ID NO: 1 , SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, an analogue or fragment thereof. this. The expression of a nucleic acid sequence may also be determined, indirectly, by determining the expression of the amino acid sequence encoded by said sequence, by means of any technique known in the art, such as Western-Biot, ELISA, BRADFORD or LOWRY method, or as indicated below. The qualitative or quantitative measurement, expression, maturation, or activity of an amino acid sequence of the invention may be carried out by any method known to those skilled in the art. . As methods for detecting the expression, the maturation, or the activity of an amino acid sequence, mention may be made of Western blot, blot-blot, dot-blot, single or multiplexed Enzyme Linked Immuno-Sorbent Assay (ELISA) methods, proteomics or glycomic methods, staining polypeptides in a silver-based dye polyacrylamide gel, Coomassie blue, or SYPRO, immunofluorescence, UV absorption, immunohistochemical methods in conventional electron or confocal microscopy, FRET (fluorescence resonance energy transfer), TR-FRET methods (time resolved FRET / FRET in time resolution), fluorescence lifetime imaging microscopy (FLIM) methods, FSPIM methods (fluorescence spectral imaging microscopy / spectrum microscopy imaging) fluorescence recovery), fluorescence recovery alter photobleaching (FRAP) methods, reporter gene methods, atomic force microscopy (AFM) methods, surface plasmon resonance methods , microcalorimetry methods, flow cytometry methods, biosensor methods, radioimmunoassay (RIA) methods, isoelectric focusing methods, and enzymatic tests, methods using peptide chips, sugar chips, antibody chips, mass spectrometry methods, SELDI-TOF spectrometry methods (Ciphergen).

More generally, immunoenzymatic assay methods from more quantitative and sensitive protein solutions can in particular be used. These ELISA methods combine couples of capture antibodies and specific detection of the targeted antigen. Specifically developed commercial or polyclonal, monoclonal or recombinant antibodies can be used. High capacity multiplexed ELISA techniques can also be implemented. It is thus possible to mention the Luminex antibody-type multiplexed approach (for example Bioplex from Bio-Rad), of the antibody-on-flat surface type ("antibodies-arrays") (for example, an approach proposed by MesoScale Discovery).

In particular, it may be advantageous to detect the expression of an amino acid sequence of the invention by means of an antibody, where appropriate in a labeled form. Such an antibody can be labeled with a directly detectable or detectable substance by reaction with another reagent. By "antibodies" is generally meant monoclonal or polyclonal antibodies, as well as immunoglobulin fragments capable of binding an antigen and which may be produced by any genetic engineering technique known to those skilled in the art. by enzymatic or chemical cleavage of intact antibody. An antibody that can be used as a skin condition assessment tool can be obtained by any method known to those skilled in the art, as described in "Antibodies: A Laboratory Manual". , Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1990).

According to a preferred embodiment, it may be advantageous to detect the expression of an amino acid sequence of the invention by means of a differential proteomic method "iTRAQ". According to a preferred embodiment, it may be advantageous to detect the expression of an amino acid sequence of the invention by means of a Western blot. Such methods are known to those skilled in the art and may advantageously be implemented as described in the examples below. In particular, the term "activity" with respect to an amino acid sequence of the invention means an antimicrobial activity, an activity for stimulating cell survival, an activity for stimulating cell proliferation, or a activity of reducing or preventing dry skin and / or signs of skin dryness, as indicated above. Such activity can be determined by any method known to those skilled in the art, such as, for example, by evaluating the proliferation or survival of epidermal cells in cultures, such as keratinocytes, or by evaluating the activity. antimicrobial on cultured bacteria, such as Staphylococcus aureus or Escherichia coli. Preferably, the determination of a state of hydration of the skin or the characterization of the effectiveness of a cosmetic treatment of the dry skin can be carried out by measuring the variation of the expression of a sequence of amino acids of the invention, and preferably represented by a sequence selected from SEQ ID NO: 14, SEQ ID NO: 15 or SEQ ID NO: 16, an analogue or a fragment thereof.

The methods of the invention are particularly advantageous in that their implementation does not require the use of an invasive technique. An epidermis sample can thus be obtained by so-called "stripping" techniques and directly analyzed by a conventional analysis technique known to those skilled in the art. These strippings are tacky surfaces applied to the surface of the epidermis such as 3M's Blenderm, D'squam (commercial adhesive from CuDERM), cyanoacrylate glue or the "stripping" varnish method. Thanks to these "strippings", adherent corneocytes and the contents of their intercellular spaces can be removed and subsequently subjected to an extraction allowing access to the protein content. Sampling of a sample suitable for a process of the invention may also be carried out more directly by "washing" the skin surface, for example by means of turbine-type propellers such as spiral cells. as described in patent FR 2,667,778 associated with a fluid circuit, or simply by adding / removing a drop of buffer on the surface of the skin. As an indication, other sampling methods adapted to the implementation of the invention may be mentioned, such as scraping methods of the upper part of the stratum corneum by means of a bimetallic system. This technique allows the collection of scales that can then be directly analyzed by different techniques to determine the levels of minerals, amino acids or lipids. Advantageously, one of the markers of the invention can be used for purposes of preclinical selection, more effective and more rigorous, of individuals, with a view to evaluating the effectiveness of treatment or cosmetic active for the care of dry skin. Also, a biomarker of the invention may advantageously be used as indicated above to evaluate the efficacy of an active agent, in vitro, ex vivo or in vivo, with respect to a deficit in hydration of the skin. , or dry skin or signs of dry skin.

Also, a biomarker of the invention can be used to establish a personalized advice of a cosmetic treatment for an individual according to its expression profile of cutaneous biomarkers.

Screening According to one of its aspects, the present invention relates to the use of an amino acid sequence, of nucleic acids of the invention, for screening or in a screening method, in particular in vitro or ex vivo, of active agents or physical treatments, particularly suitable for the care of the skin and intended to promote and / or enhance the hydration of the skin.

The active agents or the screened physical treatments may in particular be suitable for the care of dry skin, and / or for the prevention and / or treatment of the signs of cutaneous dryness.

A use or a method of the invention may comprise comparing a measurement of the activity, expression or processing of an amino acid sequence or nucleic acid sequence according to the invention. invention to a reference measurement.

A reference measurement may be as previously defined. In particular, a reference measurement may be a quantitative or qualitative value relative to the expression, the maturation or the activity of said sequences determined in a sample in the absence of active agent or physical treatment tested. Thus, a reference measurement can be obtained by repeating the steps of a method of the invention, and in particular steps a), b) and c) of a method of the invention as defined above, in the absence of biological or chemical compounds, or physical treatments to be tested. A comparison of the test measurement with a reference measurement, and an observation of a deviation or absence of deviation between the two measurements, makes it possible to draw information as to the effect of the active agent or the physical treatment. tested. The quantitative or qualitative determination of the expression, the maturation or the activity of an amino acid sequence or of a nucleic acid sequence of the invention may be carried out by any method known to man of art, and especially as described above.

According to one embodiment, the screening of an active agent or a physical treatment capable of modulating the activity of an amino acid sequence of the invention can be done by measuring the activity or the expressing a target molecule belonging to the signaling or metabolism pathways in which may be involved said of an amino acid sequence, such as for example a reporter gene system. According to one embodiment, a method of the invention can be implemented in a cell-free system, i.e. in a system not comprising cells but reproducing cellular functions, or in an isolated cell sample. A method according to the invention can be carried out on an isolated cell sample, an acellular sample, an isolated amino acid sequence or an isolated nucleic acid sequence of the invention, obtained by cutaneous biopsy, from cells in culture, in particular from an epidermal model, or a non-invasive skin surface sample, in particular by stratum corneum tape-stripping or by simple washing, as previously described. Advantageously, as a cellular sample that is suitable for the invention, there may be mentioned a sample of keratinocytes or any other cell type of the skin expressing an amino acid sequence of the invention. Preferably, the screening of an active agent or a physical treatment can be carried out by measuring the variation of the expression, in the presence and absence of the active agent or the screened physical treatment, of a sequence of amino acids of the invention, and preferably represented by a sequence selected from SEQ ID NO: 14, SEQ ID NO: 15, or SEQ ID NO: 16, an analogue or a fragment thereof.

Modulating agent For the purposes of the present invention, the term "modulating agent" or "active agent or a physical treatment capable of modulating the expression, the maturation or the activity of an amino acid sequence or of a sequence nucleic acids according to the invention ", any compound or physical phenomenon capable of acting, directly or indirectly, on at least one amino acid sequence or a nucleic acid sequence in accordance with the invention, or on a element of an intra or extracellular signaling pathway, or a metabolic pathway, or transcriptional and / or translational regulation involving said amino acid sequence or said nucleic acid sequence. For the purposes of the invention, the term "modulate", with respect to a given effect, the action of stimulating or inhibiting this effect. The active agents or the physical treatments resulting from a screening according to the invention can be advantageously used for cosmetic purposes, in particular with regard to the hydration of the skin, and in particular dry skin or signs of dry skin.

According to one embodiment, an active agent of the invention may be a stimulating agent for the activity, expression or maturation of an amino acid sequence of the invention.

In particular, a stimulating agent may be chosen from among a lysate of Bifidobacterium sp. and a mixture of a lysate of Bifidobacterium sp. and phytosphingosine-salicylate. Preferably, a lysate of Bifidobacterium sp. may be a lysate of Bifidobacterium longum. A lysate of Bifidobacterium longum suitable for the invention may be the lysate registered under the name INCI: Bifidat ferments Lysate, under the name EINECS: Bifidobacterium longum, under the EINECS No.: No. 306-168-4, and under the N ° CAS: N ° 96507-89-0. Such a lysate is sold, for example, under the name Repair Complex CLR® by K. Richter GmbH.

A mixture composed of a lysate of Bifidobacterium sp. and phytosphingosine-salicylate according to the invention may comprise a lysate of Bifidobacterium longum as defined above and a phytosphingosine-salicylate derivative. A phytosphingosine-salicylate derivative that is suitable for use in the invention may be the derivative sold by the company Evonick GOLDSCHMIDT under the name Phytosphingosine SLC®. A mixture according to the invention may comprise a lysate of Bifidobacterium sp. at a rate of 10% and a phytosphingosine-salicylate derivative at a rate of 0.002%. As a modulating agent that can be screened according to a use or a process in accordance with the invention, mention may also be made of antibodies or interfering RNAs.

Compositions The present invention also relates to compositions, cosmetic, pharmaceutical or dermatological, comprising in a physiologically acceptable medium an effective amount of at least one amino acid sequence of the invention, or at least one nucleic acid sequence of the invention, or at least one active agent capable of modulating the activity, the expression or the maturation of said amino acid sequence or of said nucleic acid sequence. For the purposes of the present invention, the term "physiologically acceptable medium" is intended to mean a medium that is suitable for the administration of a composition topically to the skin, the scalp, or the lips, or orally or by the route. parenteral, such as the intradermal or subcutaneous route.

A composition of the invention may contain adjuvants customary in the field in question, such as hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic additives, preservatives, antioxidants, solvents, perfumes, fillers, filters, absorbers odor and coloring matter.

The amounts of the various constituents of the compositions according to the invention are those conventionally used in the fields under consideration. The amount of amino acid sequence, or nucleic acid sequence of the invention, or active agent according to the invention contained in a composition of the invention, also called "effective amount" is, of course depending on the nature of the asset and the effect sought and may therefore vary to a large extent. To give an order of magnitude, a composition may contain an amino acid sequence, or a nucleic acid sequence, or an active agent according to the invention in an amount representing from 0.00001% to 50% of the total weight of the composition, in particular in an amount representing from 0.001% to 10% of the total weight of the composition, and more particularly in an amount representing from 0.1% to 1% of the total weight of the composition. According to another embodiment, a composition of the invention may comprise, in addition, at least one additional active cosmetic and / or therapeutic agent.

Additional active ingredients As examples of additional active agents that can be used in the context of the present invention, mention may be made of cosmetic oils, such as silicone oils, vegetable oils of the triglyceride type, and hydrocarbon oils such as oil. PARLEAM and esters of fatty acids and fatty alcohol.

It may also be possible to use other active agents that make it possible to improve the state of the skin and / or its appendages, such as anti-aging active agents or other moisturizing or moisturizing agents or active agents that make it possible to improve the natural lipid barrier, such as ceramides, cholesterol sulphates and / or fatty acids, and mixtures thereof.

It may also be possible to use enzymes having an activity on the skin and / or its annexes, such as proteases, lipases, glucosidases, amidases, cerebrosidases and / or melanases, and mixtures thereof.

Other examples of active agents that are suitable for the implementation of the present invention include: analgesic active agents, anti-yeast active agents, antibacterial active agents, antiparasitic active agents, antifungal active agents, antiviral active agents, anti-inflammatory active agents steroidal agents, anesthetic active agents, antipruritic active ingredients, keratolytic active agents, anti-free radical active agents, anti-seborrhoeic active ingredients, anti-dandruff active ingredients, anti-acne active agents, active agents to prevent skin aging and / or to improve its condition, anti-dermatitis active agents, anti-irritant active ingredients, immunomodulatory active ingredients, active agents for the treatment of dry skin, antiperspirant active ingredients, anti-psoriatic active ingredients, protective active ingredients against UV, antihistamine active ingredients, healing active ingredients, self-tanning active ingredients, antioxidants such as green tea or active fractions thereof, l glycerine, laponite, caffeine, aromatic essential oils, dyes, depigmenting agents, lipo-regulators, softening, refreshing, deodorant, numbing, whitening, nourishing, active ingredients that reduce differentiation and / or proliferation and / or skin pigmentation, and mixtures thereof. As additional active agents that may be more particularly suitable for the invention, mention may also be made of probiotic microorganisms, other than those considered in the lysate previously described, of prebiotic active agents, active agents promoting the synthesis of skin defense factor. , agents that make it possible to restore the differentiation / proliferation equilibrium of the cells of the epidermis, in particular such as retinol-like or retinol-like active agents, moisturizing active agents or active agents stimulating cutaneous protease activity, in particular Cathepsin D.

The present invention relates to the cosmetic use of an effective amount of at least one amino acid or nucleic acid sequence of the invention or at least one activity-modulating agent, of the expressing or maturing said amino acid sequence or said nucleic acid sequence, and in particular a modulating agent as defined above, as an active agent for promoting and / or enhancing the hydration of the skin. According to a preferred embodiment, a use of the invention may be dedicated to preventing and / or treating dry skin and / or signs of dry skin.

According to another aspect, the present invention relates to a cosmetic process, or non-therapeutic, for promoting and / or strengthening the hydration of the skin, and preferably for preventing and / or treating dry skin and / or signs of dryness of the skin in an individual in need, the method comprising at least one step of administering to said individual at least one composition comprising as active agent (i) at least one amino acid sequence of the invention or (ii) ) at least one nucleic acid sequence of the invention, or (iii) at least one agent modulating the activity, expression or maturation of said sequences of the invention, in particular as defined above .

A method or a use of the invention makes it possible to confer and / or restore a hydrated and healthy appearance to the skin, manifesting itself in a smooth, elastic, toned or firm skin, or a luminous complexion. A method or a use of the invention makes it possible to prevent and / or reduce the presence of scales, roughnesses, crevices, scales and / or wrinkles or wrinkles associated with dry skin or lack of hydration. . A method or use of the invention enhances the barrier properties of the skin. Preferably, a method of the invention may comprise topically applying to at least a portion of the skin of an individual in need thereof, particularly to the skin of the face and / or décolleté, of at least one layer of a topical composition of the invention. Advantageously, a method of the invention topically may comprise the application on the skin, and in particular on the skin of the face, of a composition of the invention in the form of a mask. A topical cosmetic process according to the invention may advantageously comprise the application of a composition of the invention, in combination simultaneously, sequentially or separately in time with an additional cosmetic or dermatological composition distinct from the composition of the invention. the invention and intended for care and / or make-up of the skin. According to another preferred embodiment, a cosmetic process of the invention may be carried out orally, in particular by administration of at least one food or dietary composition for cosmetic purposes.

According to another preferred embodiment, a cosmetic process of the invention may be carried out parenterally. The parenteral use of a cosmetic process of the invention is carried out to the exclusion of any surgical intervention and is intended only to exert a surface treatment of the skin for aesthetic purposes. Thus, a cosmetic process of the invention parenterally is implemented by any injection technique or device suitable for intraepidermal injection and / or intradermal and / or subcutaneous.

Such administration may be effected, for example, by mesotherapy. A cosmetic process parenterally is therefore translated only by a superficial break in the skin and therefore goes out of any medical or therapeutic setting. For the parenteral route, alternatively, systemic patch administration may be preferred.

A cosmetic process according to the invention may be carried out on a daily basis, for example on the basis of a single administration per day, or of a divided administration in two or three times a day, for example once in the morning and once in the morning. times in the evening. A cosmetic process according to the invention may be carried out over a period of time varying from one week to several weeks, or even several months, this period being able to be repeated after periods of non-treatment for several months or even several years. . By way of example, a cosmetic process according to the invention may be provided for administering a composition of the invention, for example, at a rate of 1, 2 or 3 times a day, or more, and generally over a period of time. extended by at least 4 weeks, or even 4 to 15 weeks, with one or more periods of interruption if necessary.

Figure 1: represents the variation of the expression of Dermcidin (average ± sem) measured by Western Biot according to the degree of hydration of the skin.

For the purposes of the present invention, "a" must be understood, unless otherwise indicated, in the sense of "at least one".

The examples and figures below are presented for illustrative and not limiting of the invention.

EXAMPLES

EXAMPLE 1 Expression of Dermcidin in Skin 1- Materials and Methods a Western-Biot Protocol The detection of Dermcidine expression (DCD) was carried out using a Western-Biot method. The principle of this method is as follows: the proteins are separated by electrophoretic migration on a 10-20% SDS-PAGE criterion gel (Bio-Rad). After a semi-dry transfer on a PVDF membrane, the proteins are incubated in a blocking solution (TBS + 0.1% Tween + 1% milk) and then incubated with the primary antibody directed against the protein of interest overnight at 4 ° C. . A second incubation with the secondary antibody (peroxidase coupled) directed against the primary antibody is performed for one hour at room temperature. Depending on the degree of sensitivity, different kits are used for revelation: ECL, ECL + or ECL Advance (Amersham). The image is acquired at F1uorSmax (Biorad) and quantified bands using Quantity-One software (Biorad) Protein Nature Antibody Dilution Antibody Detection Weight samples I II mol. calculated Dermcidin Denatured Sc-1/100 IgG anti-ECL + 9kDa 27466 / poly Goat-60sec HRP b-Collection and treatment of skin samples 120 female subjects, aged 18 to 70 years, were selected for this study. Four zones per leg have been delineated (external / internal left leg, external / internal right leg). The samples are taken by Stripping Vernis (lower leg site) according to the protocol described by Mehul et al., (J. Biol Chem., 2000, 275 (17): 12841-7). analysis is performed on an area: external left leg. Samples from varnished strippings were used for Western Blot analysis. Before the samples were taken, the skin types were characterized by clinical scoring.

The clinical scoring is done by a dermatologist according to the "Atlas of dry skin on the legs" to identify the different types of skin according to the degrees below: 0: normal skin, regular cutaneous relief, smooth aspect 1: slightly dry skin, ribbed skin surface, rough appearance 2: dry skin, ribbed skin texture and some scales, rough appearance 3: very dry skin, numerous scales and some scales, rough appearance 4: extremely dry skin, numerous scales, rough appearance

Preparation of acetone powders Each 75 cm2 varnish stripping is immersed in 75 ml of acetone. The varnish dissolves and the corneocytes are in suspension. The mixture is filtered through a vacuum pump on a 40 μm nylon membrane to collect the corneocytes. Two successive washes are performed with the same volume of acetone. Acetonitrile powders of stratum corneum are obtained in dry form.

Extraction of samples Two types of extraction are carried out successively: native extraction then denaturing. Native Extraction The acetone powders are weighed and put into 1.5 ml Eppendorf tubes (Trefflab cat.No.96.07246.9.01). 100 μl of PBS 0.1% triton X100 buffer are added to 1 mg of acetone powder and the mixture is left for one hour in contact with ice. Then it is ground for 30 seconds in the ice. The medium is then recovered in 0.45 μm Millipore Ultraree columns and then centrifuged for 5 min at 10,000 g at 4 ° C.: the supernatant is then collected. A protein assay is performed according to the BCA technique (BCA Pierce kit). The samples are adjusted to a concentration of 0.15 mg / ml in Laemmli 4X buffer and stored at -20 ° C pending analysis.

Denaturing Extraction It is made from the base of the native extract. In 1.5 ml Eppendorf tubes (Trefflab cat.No.96.07246.9.01) 1001.11 of Laemmli 1X buffer is added to the pellet for 1 mg of acetone powder. The mixture is boiled for 10 min at 90 ° C and then milled for 20 seconds and centrifuged for 10 min at 10000 g / min. The supernatant is collected. A protein assay is performed according to the Bradford technique. Samples are adjusted to 1 mg / ml and stored at -20 ° C pending analysis.

These skin samples are then analyzed by Western-Biot as previously described. The results were obtained from the denatured extracts.

Statistical Analyzes The effect of skin dryness (clinical score) on the level of expression of bio-markers was analyzed both graphically by representing mean values with their confidence interval as a function of age classes or Clinical score of cutaneous dryness, and using a multiple regression model with age and cutaneous dryness score parameters in covariates. The significance of the coefficients (Student's test) associated with the covariates makes it possible to test the association between the bio-marker studied with age and the drought score. Taking into account the two parameters in the model makes it possible to estimate the effect of one of the parameters while adjusting on the effect of the second (everything else being equal). The level of significance of the tests is set at 5% in an unadjusted bilateral approach. The analyzes were carried out using SPPSS software version 17. The levels of expression of the bio-markers were previously transformed (square root or Log10) when it was useful to both symmetrize their distribution and stabilize their variance. .

2- Results The results obtained, illustrated in FIG. 1, clearly show a decrease in the expression of Dermcidine correlated with an increase in the degree of dehydration, or dryness, of the epidermis.

Statistical analysis confirms a significant decrease in the expression of Dermcidine in dry skin compared to normal skin (p = 0.046). This study validates the use of Dermcidine as an exceptional biomarker of skin hydration, especially dry skin. Example 2 Effect of a lysate of Bifidobacterium sp. on the expression of Dermcidin

1- Materials and Methods The samples of skin samples, and the measurements of the expression of Dermcidine are carried out as indicated in Example 1. The volunteers are female subjects aged 30 to 65 years presenting a clinical score dry skin greater than or equal to 2. They were combined and divided into two subgroups according to the treatment administered, a "placebo" group, and a "treated" group. The "treated" group receives topically, on the leg, twice daily, morning and evening, for 56 days, ie 2 months, a composition comprising 10% Repair Complexe in a support formula corresponding to a oil emulsion in demineralised water Arlacel / Myrj containing 5% Parleam, 15% cyclopentasiloxane, 3% glycerin and 2% petrolatum. The Repair Complex comprises a lysate of Bifidobacterium longum registered under the name INCI: Bifida ferment Lysate, under the name EINECS: Bifidobacterium longum, under the EINECS No.: No. 306-168-4, and under the CAS No. N 96507-89-0. This lysate is marketed under the name Repair Complex CLR® by K. Richter GmbH. On the other hand, the "Placebo" group receives only the support formula.

The skin samples are then proteomically analyzed using the so-called "isobaric labeling" technique, using the Appliance Biosystems iTRAQ Reagents Multiplex kit (4352135) according to the manufacturer's instructions. The detection of Dermcidin expression (DCD) was performed using the iTRAQ method (Isobaric Tagging Reagents for Quantitative Proteomic Analysis) developed by Applied Biosystems. This method allows the quantification of peptides previously labeled with an isobaric tag. There are 4 different tags and up to 4 different types of samples can be compared in the same LC / MS-MS analysis.

The principle of this method is as follows: Digestion of protein extracts and labeling: First, each protein extract is digested by a proteolytic enzyme: trypsin. In a second step, each peptide mixture obtained is labeled with an isobaric tag having a total mass 145, comprising a "reporter" group of mass 114, 115, 116 or 117, and a mass "balance" group 31, 30, 29 or 28, linked together by an MS fragmentation site. The labeling is obtained by reacting the Peptide Reactive Group of each tag with the primary amines of the peptides (N-terminal end of the peptides or the lysine or tyrosine side chain) LC / MS-MS analysis and quantification: After the step labeling, the samples are pooled and analyzed by mass spectrometry.A given peptide, present in several samples, will have an identical parent mass but its MS / MS fragmentation spectrum will generate the mass of the reporter group characteristic of each of the reagents The comparison of the intensity of each reporter ion (114, 115, 116 or 117) then makes it possible to quantify the peptide The iTRAQ method is more precisely described by Zieske (J. Exp.Bot., 2006, 57: 1501 ) or Wiese et al (Proteomics, 2007, 7: 340).

For each subject condition "Treaty" and "Placebo", an average of the ratios J56 / OJ is obtained, thus making it possible to evaluate the effect of the treatment. The J56 / OJ ratios are calculated according to the following formula:

% effect of treatment = 100 * Ratio J56 / OJ "Treaty" - Ratio J56 / OJ "Placebo" ratio J56 / OJ "Placebo" 2- Results The raw data obtained at the end of the experiment are as follows: Experience 1 Ratio J56 / JO Ratio J56 / JO Placebo Treaty 2,70 3,10 Experience 2 Ratio J56 / JO Ratio Placebo J56 / JO Treaty 1,00 1,62 The average value of the ratio J56 / JO "Placebo" is 1.85 while the average value of ratio J56 / OJ "Treaty" is 2.36. Treatment with Repair Complex® results in a 27% increase in signal compared to placebo. Thus the topical administration of a Bifidobacterium longum lysate increases the expression of Dermcidine by approximately 30% after 2 months of treatment. Topical administration of a lysate of Bifidobacterium sp. Thus, it is possible to restore a level of expression of Dermcidin in dry skin, which is conducive to reinforcing its protective action on the skin, reinforcing the barrier properties of the skin, and reducing the signs of dry skin. This study also validates the use of Dermcidin as a biomarker to evaluate the efficacy of a cosmetic treatment of dry skin, as well as a tool for screening new active agents for the treatment of the skin. dry skin.

Example 3 Effect of a lysate mixture of Bifidobacterium longum and phytosphingosine salicylate on the expression of Dermcidine

1- Materials and methods

Samples of skin samples, and measurements of the expression of Dermcidine are carried out as indicated in Example 2.

Volunteers are female subjects aged 40 to 45 years old with dry skin on the areas sampled (dermascore assessment). Each subject is his own control, both arms are removed but only one is treated with the tested product and the second arm receives a placebo.

The "treated" arm receives, topically, twice daily, morning and evening, for 56 days, ie 2 months, a composition comprising 10% of Repair Complexe and 0.002% of Phytosphingosine-SLC in a corresponding support formula. an oil-in-demineralized water emulsion Arlacel / Myrj containing 5% Parleam, 15% cyclopentasiloxane, 3% glycerine and 2% petrolatum.

The Repair Complex comprises a Bifidobacterium longum registered under the name INCI: Bifida ferment Lysate, under the name EINECS: Bifidobacterium longum, under the EINECS N °: 306-168-4, and under the CAS N °: 96507- 89-0. This lysate is marketed under the name Repair Complex CLR® by K. Richter GmbH.

The phytosphingosine-salicylate derivative is that marketed by the company Evonick GOLDSCHMIDT under the name Phytosphingosine SLC®. The "Placebo" arm receives only the support formula. For each "Treaty" and "Placebo" condition, an average of the J56 / OJ ratios is obtained as indicated above, thus making it possible to evaluate the effect of the treatment. 2- Results The raw data obtained at the end of the experiment are the following: Experiment n ° 1 Ratio J56 / JO Ratio J56 / JO Placebo Treaty 0.75 1.66 Experiment n ° 2 Ratio J56 / JO Ratio J56 / JO Placebo Treaty 0.45 0.81 The average value of the J56 / OJ "Placebo" ratio is 0.6, while the average value of the "Treaty" J56 / OJ ratio is 1.235.

The treatment effect is equal to 105%, and reflects a doubling of the expression of Dermcidine compared to "placebo". Thus, topical administration of a mixture comprising a Bifidobacterium longum lysate and phytosphingosine salicylate increases the expression of Dermcidin by more than 100%. The topical administration of a mixture comprising a Bifidobacterium longum lysate and phytosphingosine-salicylate thus makes it possible to restore a level of Dermcidin expression at the level of the skin, and in particular of the dry, favorable skin. to reinforce its protective action of the skin, to strengthen the barrier properties of the skin, and to reduce the signs of cutaneous dryness.

BIBLIOGRAPHY

Baechle, D., Flad, T., et al. (2006). "Cathepsin D is present in human eccrine sweat and involved in the postsecretory processing of the antimicrobial peptide DCD-1L" J. Biol. Chem. 281 (9): 5406-5415. Cunningham, T.J., L. Hodge et al. (1998) J. Neurosci 18 (18): 7047-7060. Flad, T., Bogumil R. et al. (2002) "Detection of dermcidin-derived peptides in 10 sweat by ProteinChip Technology" J. Immunol. Methods 270 (1): 53-62. Kenney, W.L. and S.R. Fowler (1988) "Methylcholine-activated eccrine sweat gland density and output as a function of age" J. Appl. Physiol. 65 (3): 1082-1086. Kyte et al., (1982) J. Mol. Biol., 157: 105. Mehul B. et al., (2000) "Identification and Cloning of a New Calmodulin-like Protein from Human Epidermis" J. Biol. Chem. 275 (17): 12841-12847 Moreira, D.F., B.E. Strauss et al. (2008) Genes up-and-down-regulated by dermcidin in breast cancer: a microarray analysis Genet. Mol. Res. 7 (3): 925-932. Niyonsaba, F. A. Suzuki et al. (2009) "The human antimicrobial peptide dermcidin activates normal human keratinocytes" Br. J. Dermatol. 160 (2): 243-249. Rieg, S.C., Garbe et al. (2004) "Dermcidin is constitutively produced by eccrine sweat gland and is not induced in epidermal cells under inflammatory skin conditions" Br. J. Dermatol. 151 (3): 534-539. Rieg S., Steffen II et al. (2005) "Deficiency of dermcidin-derived antimicrobial peptides in patients with atopic dermatitis correlates with an impaired innate defense of human skin in vivo" J. Immunol. 174 (12): 8003-8010. Sakurada K., T. Akutsu, et al., (2009) "Detection of dermcidin for sweat identification by real-time RT-PCR and ELISA" Forensic. Sci. Int. 2010 Jan. 30; 194 (1-3): 80-4. Epub 2009 Nov. 13. Sambrook et al., 1989, Vol. I-III, Coldspring Harbor Laboratory, Coldspring Harbor Press, NY. Schittek, B, R. Hipfel et al. (2001): "Dermcidin: a novel human antibiotic secret peptide by sweat tassels" Nat. Immunol. 2 (12): 1133-11137.

Watchorn, T. M. N. Dowidar et al. (2005) "The chachectic mediator proteolysis inducing factor activates NF-kappaB and STAT3 in human kupffer cells and monocytes" Int. J. Oncol. 27 (4): 1105-1111. Wiese et al., (2007) Protein labeling by iTRAQ: A new tool for quantitative mass spectrometry in proteome research Proteomics 7 (3): 340-350 Zieske et al. (2006) "A perspective on the use of iTRAQ reagent technology for protein complex and profiling studies" J. Exp. Bot. 57 (7): 1051-1058.

Claims (16)

REVENDICATIONS1. Use of (i) at least one acid sequence CLAIMS1. Use of (i) at least one amino acid sequence encoded by a nucleic acid sequence represented by SEQ ID NO: 1, an analogue or a fragment of said amino acid sequence, or ü) of said nucleic acid sequence, as a biomarker of a state of hydration of the skin. 2. Use according to the preceding claim, wherein said nucleic acid sequence. is represented by a sequence selected from SEQ ID NO 2 to SEQ ID NO: 8, an analogue or a fragment thereof. The use according to claim 1 or 2, wherein said amino acid sequence is represented by a sequence selected from SEQ ID NO: 9 to SEQ ID NO: 16, an analogue or a fragment thereof, and preferably is selected from SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, an analogue or a fragment thereof. 4. Use according to any one of the preceding claims, wherein a decrease in the activity, expression or maturation of said bioniarter is indicative of skin deficient in hydration. 5. Use (i) of at least one amino acid sequence as defined in claims 1 to 3, or '(ii) of at least one nucleic acid sequence as defined in claims 1 or 2, for screen for active agents or physical treatments that may modulate activity; expressing or maturing said amino acid sequence or said nucleic acid sequence and intended to promote and / or enhance the hydration of the skin. 6. Use (i) of at least one amino acid sequence as defined in claims 1 to 3, or (ii) at least one nucleic acid sequence as defined in claims 1 or 2, for characterizing the effectiveness of a cosmetic treatment of dry skin and / or signs of dry skin. 7: Cosmetic use of an effective amount (i) of at least one amino acid sequence as defined in claims 1 to 3, or (ii) at least one nucleic acid sequence as defined in claim 1 or 2, or (iii) at least one agent modulating the activity, expression or maturation of said amino acid sequence or said nucleic acid sequence, as an agent active to promote and / or enhance the hydration of the skin. 8. Use according to the preceding claim, for preventing and / or treating dry skin and / or signs of dry skin. 5 9. Use according to the preceding claim, for preventing and / or treating senile or fragile dry skin, or xerosis, in particular chosen from xerosis vulgaris, xerosis senile, and xerose winter. 10. Use according to any one of claims 7 to 9 for preventing and / or treating sensations of tightness and / or itching associated with dry skin. 11. Use according to one of claims 6 or 8, wherein the signs of cutaneous dryness are chosen from the skin withered, the lack of elasticity, flexibility and / or tone of the skin, the rough touch, the presence of crevices, desquamation, scaling, or wrinkles and fine lines associated with dry skin. 15 12. A pharmaceutical or dermatological composition comprising in a physiologically acceptable medium an effective amount of (i) at least one amino acid sequence as defined in claims 1 to 3, or (ü) of at least one sequence of nucleic acids as defined in claims 1 or 2, or (iii) at least one agent modulating the activity, expression or maturation of said amino acid sequence or said acid sequence nucleic acids, as an active agent for preventing and / or treating pathological constitutional dry skin selected from atopic dermatitis and ichthyosis. 13. In vitro or ex vivo method for characterizing a hydration state of the skin comprising at least the steps of a) performing, in an isolated skin sample, a qualitative or quantitative measure of the expression, the processing or activity of said amino acid sequence as defined in claims 1 to 3 or of said nucleic acid sequence as defined in claims 1 or 2, and b) comparing said measurement carried out at step (a) a reference measure. 30 14. A method for in vitro or ex vivo screening of active agents or physical treatments capable of modulating the activity, expression or maturation of an amino acid sequence as defined in claims 1 to 3, or a nucleic acid sequence as defined in claims 1 or 2, and intended to promote and / or enhance the hydration of the skin, comprising at least the steps of: a) disposing said amino acid sequence or said sequence nucleic acid under conditions conducive to the activity, expression or maturation of said sequences, b) contacting said amino acid sequence or said nucleic acid sequence with at least one active agent to be tested, or exposing said amino acid sequence or said nucleic acid sequence with a physical treatment to be tested, c) performing a qualitative or quantitative measurement. the expression, the processing or the activity of said amino acid sequence or said nucleic acid sequence, and d) comparing said measurement with a reference measurement. 15. A cosmetic process for promoting and / or enhancing skin hydration in an individual in need thereof comprising at least one step of administering to said individual at least one composition comprising as active agent (i) minus an amino acid sequence as defined. in claims 1 to 3, or (ii) at least one nucleic acid sequence as defined in claims 1 or 2, or (iii) at least one agent modulating the activity, expression or maturation of said sequences. 20 16. Cosmetic process, in vitro or ex vivo, for characterizing the effectiveness of a cosmetic treatment of dry skin and / or signs of cutaneous dryness in an individual in need, comprising at least the steps of: a) performing, before carrying out the cosmetic treatment, in a first isolated skin sample taken from said individual, at least a first qualitative or quantitative measurement of the expression, the maturation or the activity of at least one amino acid sequence as defined in claims 1 to 3, or at least one nucleic acid sequence as defined in claims 1 or 2, b) perform, after the implementation of the cosmetic treatment, in a second . isolated skin sample taken from said individual, at least a second, qualitative or quantitative measure of expression, maturation or activity of said amino acid sequence or said nucleic acid sequence, etc.) comparing the first and second measurements, in particular to derive information relating to an effect at least of the implementation of the cosmetic treatment.