FR2974371A1 - Characterization of skin pigment spot apparent in human, comprises comparing expression levels, in skin sample form spot and unwounded adjacent skin, of dermal gene e.g. EFEMP1 of a family of extracellular glycoproteins and proteoglycans - Google Patents

Abstract

Method of characterization of skin pigment spot apparent or suspected in a human, comprises comparing expression levels, in skin samples form the spot and unwounded adjacent skin, of at least a dermal gene of a family of extracellular glycoproteins and proteoglycans, where the gene is EFEMP1, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 or FLRT2. Independent claims are included for: (1) a method of evaluating the efficacy of a treatment of skin pigment spots comprising comparing expression levels, in skin samples form the spot after such a spot, before and after treatment, of the dermal gene of the family of extracellular glycoproteins and proteoglycans; (2) an in vitro method for evaluating the efficacy of a treatment of skin pigment spots, comprising comparing, before and after treatment, the level of expression in a representative cellular model of the skin, of the dermal gene of the family of extracellular glycoproteins and proteoglycans or the level of expression or activity of the expression product of the selected gene; (3) cosmetic method of treatment or prevention of skin pigment spot of non-pathological human skin comprising modulating the level of expression or activity of the gene of a family of extracellular glycoproteins and proteoglycans, where the modulation is effected through the use of an antisense molecule, an small interfering (si)RNA or a microRNA; (4) use of a modulator of the expression level or activity of the expression product of the gene, for cosmetic applications in the treatment of non-pathological skin pigment spots, where the modulator is an antisense molecule, siRNA, a microRNA, letrozole or anastrozole; and (5) a modulator of the expression level or activity of the expression product of the dermal gene. ACTIVITY : Dermatological. MECHANISM OF ACTION : Gene expression modulator.

Description

The present invention is in the cosmetic field, it relates to the skin. It fits more generally in the context of the characterization of the pigmentary spots of the skin and the treatment of these spots.

The color of the skin is mainly due to the presence of a pigment, melanin in the epidermis. Melanin is synthesized by specific dendritic cells located in the basal layer of the epidermis, the melanocytes. Melanogenesis takes place in organelles, melanosomes which, loaded with melanin, are transferred to neighboring epidermal cells, the keratinocytes, via the dendrites. The color of the skin, or constitutive pigmentation varies according to the individuals depending on the amount of melanin produced as well as the chemical nature of melanins. Melanins are macromolecules formed from tyrosine (eumelanin) or tyrosine and cysteine (pheomelanin). Synthesis mechanisms involve enzymes, the main ones being tyrosinase and tyrosinase-associated protein (Tyrp-1). Naturally, the pigmentation of the skin is stimulated by the exposure to the sun, it is the phenomenon of tanning. There are, however, situations where the pigmentation process is impaired, and which can lead to pigmentation defects, hypopigmentations (vitiligo, albinism) or conversely to an excess of pigmentation, hyperpigmentations. Among the benign hyperpigmentary disorders, characterized by an abnormal accumulation (excluding tanning) of melanin, mention may be made of actinic lentigo, melasma, acne pigment sequelae, post-inflammatory pigmentation, prairie dermatitis, pigmentation related to the plant poison ivy or the benign dychromics of the face. The actinic lentigo, also called senile or solar lentigo, senile spot, age spot, or commonly referred to as "senile dirt", "cemetery daisies" or "cemetery flowers", is by far the most common pigmentary lesions. This type of lesion appears on areas of the skin that have been photoexposed, such as the face, back of the hands, upper limbs and especially the dorsal forearm, back, and especially the upper back. They usually affect individuals from the age of 40. Macroscopically, the actinic lentigines are represented by benign pigmented macules of brown color more or less dark, whose edges are clear but irregular. Of very variable size, they can extend from a few millimeters to more than two centimeters. Despite its high frequency, few studies have been published on the physiology and pathogenesis of actinic lentigines. On the basis of the rare existing histological studies, it is known that there is an increase in the overall epidermal melanic load and more particularly in the basal layer. There is also an elongation of the epidermal ridges that can take on a club-like appearance in the papillary dermis. Monfagna 1980, ber Rahman 1996, Andersen 1997, Cario-Andre 2004j. Finally, there may be anastomoses between adjacent ridges giving a bridge or network appearance.

Incontinence pigmentosa with presence of melanin and melanophages may also exist in the dermis. Current treatments: Benign skin disorders are generally considered unsightly. Due to the proven association between the appearance of actinic lentigines and chronic exposure to the sun, the prevention of their appearance usually involves the topical application of so-called photoprotective products such as sunscreens. In the case of "curative" treatments, many processes, mainly for cosmetic purposes, have therefore been developed in order to try to eliminate them or reduce their presence. The elimination or reduction of the presence of these disorders is usually based on the application of depigmenting treatments, based on the reduction of melanin synthesis activity in melanocytes. Depigmenting molecules interfere with one or more stages of melanogenesis. One of the main products used to date is the inhibition of tyrosinase, one of the key enzymes in the melanogenesis process. The purpose of these treatments is to reduce or even stop the synthesis of pigment.

The main known depigmenting substances are hydroquinone and its derivatives, kojic acid, arbutin, iminophenols, ascorbic acid and its derivatives, the combination of carnitine and quinone, the amino-phenol derivatives, and benzothiazole derivatives, natural extracts, corticosteroids, etc. Exfoliants are often also associated with these active agents to increase desquamation, and thus to eliminate more easily the melanin present in the stratum corneum. Another method of non-cosmetic treatment is to destroy the lesions by physical or chemical means using lasers or peels. However, these are fairly cumbersome procedures that do not address the etiology of the disorder. In the majority of cases, actinic lentigines reappear some time after treatment.

In addition, there are major disadvantages to existing treatments. The depigmenting substances may exhibit in particular a certain instability, a low efficiency at low concentration, a biological activity affecting other functions, toxic or allergenic properties.

In addition, because they do not target the root cause that caused the dysregulation of pigmentation, there is a great heterogeneity of response to different depigmenting treatments. Thus, for a given treatment, administered, for example, topically, a given benign skin pigment disorder, such as an actinic lentigo or melasma, may subside or disappear, while another will not evolve. This variability can be observed between lesions in different individuals but also in the same individual, between different lesions. There are therefore mild skin pigment disorders for which no topical treatment is effective today.

There is therefore a need to find more effective and more harmless treatments for this type of lesion. For this, it is necessary to identify the molecular deregulation and functional dysfunction that may exist in this type of pigment disorder in order to identify new targets and select assets to correct these defects.

In the prior art, concerning the treatment of pigment spots and more particularly of actinic lentigines, it is described the stimulation at the genomic or protein level of molecules which are closely associated with melanocytes and melanogenesis (melanogenesis enzymes, melanosome protein , key paracrine factors of melanogenesis). It is found in the epidermis or dermis for the following proteins: Tyrosinase, TRP1, DCT, Pmel-17, POMC, ET1, ETBR, SCF, c-KIT, KGF, KGFR, Hepatocyte growth factor (HGF), MIA, TRPM1, Melan-A, Pink eye dilution, P53 and IL1a. In addition, other studies describe molecular or cellular changes in solar or senile lentigo by gene or protein expression analyzes. However, from these different studies, there is no general mechanism or functional dysfunction underlying the appearance of pigment spots. No prior art document has reliably demonstrated molecular dysregulations or functional dysfunctions that may exist in this type of pigment disorder, beyond molecules closely associated with melanocytes and melanogenesis.

The present inventors have demonstrated for the first time the involvement of dermal genes linked to the extracellular matrix and to the dermal-epidermal junction in the pigment disorders resulting in pigmentary spots on the skin, and more particularly in the genes of the skin. the family of proteoglycans and extracellular glycoproteins. The extracellular matrix provides a structural role in the skin thanks to its ability to provide support and cohesion of tissues and cells and thanks to its mechanical properties which allow it to resist tensile stress (especially because of the presence of collagens), compression (especially because of the presence of proteoglycans). It plays an important biological role because it is also a major player in the regulation of epidermal and dermal homeostasis. Thanks, among other things, to its reservoir properties of growth factors and cytokines, it is involved in morphogenesis, proliferation, cell differentiation and tissue repair. The dermal-epidermal junction (DDE) is performed by the basement membrane which consists of an extracellular matrix leaflet and which separates the epidermis from the dermis. It constitutes a barrier of permeability and regulates the exchange of molecules, in particular nutrients, between the two tissues. It provides a function of attachment and anchoring of the epidermis to the underlying matrix and structural cohesion of the epithelium. It also plays an important role in the regulation of differentiation, and the migration of epidermal cells as well as the morphogenesis stages of the epidermis.

Proteoglycans are molecules with extracellular localization, membrane or intracellular, consisting of a protein called "core protein" on which are grafted polysaccharide chains called glycosaminoglycans. The structural diversity of proteoglycans allows the formation of protein and / or oside sites that interact specifically with other matrix or cell components, as well as with soluble mediators. This very large interactive capability allows proteoglycans to participate in the assembly of the matrix while giving it many rheological properties (hydration, resistance to compressive forces, filtration capacity, transparency). Proteoglycans also regulate many cellular activities (proliferation, differentiation, adhesion, migration) and participate in the control of the activity, bioavailability and stability of cytokines. Extracellular glycoproteins are proteins associated with sugars; they allow the cells to adhere to the extracellular matrix. Among the glycoproteins, fibulins constitute a family of secreted molecules associated in particular with the basement membrane, the elastic fibers.

For the first time, it has been shown by the present inventors that certain genes related to the extracellular matrix and more particularly genes of the family of proteoglycans and extracellular glycoproteins, have transcription levels significantly different between healthy skin and the skin resulting from a pigment spot, thus highlighting the link between dysregulation of proteoglycan components and extracellular glycoproteins within the extracellular matrix and modulation of pigmentation, in particular inducing the appearance of pigmentary spots. Without being bound by any theory, the modifications of expression of different genes linked to this family of genes in the dermis led the inventors to think that, because of the role played by the proteins of this family within the matrix organization, the deregulation of these genes, sign of a modification of the whole dermal compartment, disrupts the homeostasis of the epidermis and generates important modifications in particular of the histological architecture of the epidermis in the pigment spots (elongation -5- epidermal ridges in the dermis for example). As a result, the epidermal melanic charge is increased and gives rise to pigment spots.

The present invention relates to a molecular signature representative of the differences in gene expression existing between the skin resulting from pigment spot and the adjacent healthy skin, and to the various applications and methods making use of the knowledge of this signature, in particular for modulating pigmentation. skin, in the cosmetic treatment of pigment spots or to even out the complexion or to homogenize the color of the skin. This signature consists of the following 7 genes: EFEMP1 (Fibulin-like extracellular matrix-like protein 1 containing EGF, fibulin 3), ECM1 (extracellular matrix protein 1), ASPN (Asporin), HS3ST6 (heparan sulfate (glucosamine) 3- O-sulfotransferase 6), PAPLN (papiline, proteoglycan-like sulfated glycoprotein), CHSY1 (carbohydrate (chondroitin) synthase 1) and FLRT2 (leucine-rich fibronectin transembrane protein 2). Said genes are human genes so called.

The inventors have in fact demonstrated the significant and reproducible modulation of the level of expression of these genes between skin resulting from pigment spot and the corresponding healthy skin. The present invention relates in particular according to a first aspect to a method for characterizing a cutaneous pigment spot. Such a method makes it possible inter alia to confirm the nature of the pigment spot in the case where the latter is already apparent, for example visually to the naked eye. The method also makes it possible to predict the appearance of a stain, when the stain is not yet observed but only suspected, or to conclude that a skin is prone to the formation of skin spots, or prone to skin defects. pigmentation, for example when no stain is still apparent.

The skin pigment spots concerned are hyperpigmentary spots, or so-called hyperpigmented spots, corresponding to an excess of pigment, or hypopigmentary spots, or even hypo-pigmented, corresponding to pigmentation defects. Hypopigmentations that can be envisaged in the context of the present invention include vitiligo and albinism. Benign hyperpigmentary disorders that can be envisaged in the context of the invention, characterized by an abnormal accumulation (excluding bronzing) of melanin, are, for example, actinic lentigo, melasma, acne pigment sequelae, post-inflammatory pigmentation, dermatitis meadows, pigmentation related to the plant poison ivy or even benign dyschromias of the face. The pigment spots according to the present invention also include defects, imperfections or irregularities of pigmentation rendering the complexion uneven, or the color of the skin not homogeneous. The pigment spots in question are preferentially pigmented spots on human skin. However, the disorders at the level of the extracellular matrix and especially at the level of the family of proteoglycans and extracellular glycoproteins -6 in the dermis demonstrated by the present inventors being quite general, similar methods can be envisaged for other animal species also affected by pigment spots. In this case, the different methods, uses or compositions according to the invention will be implemented with the genes of the species considered, orthologous to the human genes of the invention. The method comprises comparing levels of expression within the skin from said stain and within the uninjured skin, preferably adjacent, of the same individual, at least one gene of the family of extracellular proteoglycans and glycoproteins , selected from the list consisting of genes EFEMP1, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2.

The genes EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 are the genes of the invention. They all encode constituents of the extracellular matrix, the family of extracellular proteoglycans and glycoproteins. Furthermore, said genes of the invention are called dermal genes because they are genes that are predominantly expressed in the dermis and give rise to characteristic proteins of the dermal compartment or of the dermal-epidermal junction as to its face. dermal; and this in contrast for example to keratinocyte proteins, intracellular proteins or epidermal protein in particular. The levels of expression of at least one of the genes of the invention are measured at the level of the skin resulting from a known or suspected spot, and at the level of the adjacent skin which has not been injured. Preferably, the levels are measured on skin samples taken within the spot and within an adjacent non-injured area. The samples are, for example, skin biopsies. Biopsies of a few millimeters in diameter are sufficient, for example a biopsy of 2 mm, or 3 mm in diameter. One can also consider the total excision of a lesion.

The non-lesioned area is preferably an adjacent area as close as possible to the spot but at a distance sufficient for the sample taken to contain no cells likely to belong to the pigment spot. Preferably, the non-injured adjacent area is an area having light and sun exposure comparable to the area of the pigment spot. Alternatively, the non-injured area may come from a symmetrical zone on the other part of the subject, having a perfectly identical location; for example in the case of a stain on the left hand, the uninjured area may be the corresponding area on the right hand. In this case, the non-injured area is not strictly speaking an adjacent area. The term "non-injured" means an area which does not have a pigment spot or pigment irregularity, preferably a zone that is homogeneous in terms of pigmentation.

Since the non-lesion area serves as a reference, it should in all cases be as comparable as possible to the area of the spot, but devoid of any pigment defect. By level of expression of a gene, it is preferentially understood, in the present description, the level of transcription of said gene. However, its level of expression can also be translated by its level of translation, assuming that it is a gene coding for a protein. This is the case for the genes of the invention. Concerning the evaluation of the transcription level of the chosen gene, it can be carried out by various means well known to those skilled in the art, directly or after reverse transcription. The level of transcription can in particular be evaluated by the use of commercially available RNA chips or microarrays for this purpose. A possible evaluation method is described in the experimental part. It is important to note also that the method according to the invention involves the comparison of the levels of expression of at least one of the genes of the invention. As a result, it may be sufficient to quantitatively or qualitatively assess the difference between the two levels of expression, without individually evaluating and quantifying each level of expression. The expression levels of at least one of the genes of the invention may be evaluated by reference or after normalization with the level of expression of other genes, the level of expression of which is assumed to be substantially identical within spot and in the area of non-injured skin chosen. Such genes for normalization are well known to those skilled in the art and may depend on the area of the body where the stain is located. By way of example, the following genes may be cited as being capable of serving for the normalization of the expression levels of the genes of the invention, coding for: L13a ribosomal protein (RPL13A), beta-2-microglobulin (B2M ), ribosomal protein S9 (RPS9), ribosomal protein S28 (RPS28) and G [yceraldehyde-3-phosphate dehydrogenase (GAPDH). The method according to the invention is preferably carried out in vitro or ex vivo. According to one embodiment of the method of the invention, the pigment spot is a non-pathological, benign spot, especially as opposed to pathological lesions such as naevi; it may be an irregularity in the pigmentation of the skin. Preferably, a method according to the invention comprises comparing the expression levels of at least two distinct genes among the genes of the invention, preferably at least three distinct genes, or even five distinct genes. It is also conceivable to compare the expression levels of at least 6 genes, or even 7 genes of the invention. When two genes are chosen, they are preferably selected from the lists of the following six preferred genes: EFEMP1, ECM1, ASPN, HS3ST6, PAPLN and CHSY1. For example, the selected genes may be EFEMPI and ECM1, or EFEMP1 and ASPN, or ECM1 and ASPN, or ECMI and PAPLN. All two by two combinations of the 6 preferred genes are preferred combinations for the practice of the invention. Likewise, all combinations involving one of the 6 preferred genes and one of the other 6 genes of the invention are particularly preferred. For the combinations of 3 genes, the following combinations are especially envisaged; EFEMP1, ECM1 and ASPN; EFEMP1, ECMI and HS3ST6; EFEMPI, ECMI and PAPLN; ECMI, ASPN and HS3ST6; EFEMP1, ASPN and CHSY1; and ECM1, ASPN, HS3ST6 and PAPLN. Possible combinations of 5 genes according to the present invention include the following combinations: EFEMPI, ECMI, ASPN, HS3ST6 and PAPLN; EFEMP1, ECMI, ASPN, PAPLN and CHSY1; and ECMI, ASPN, HS3ST6, PAPLN and CHSYI. A particular combination is that consisting of the EFEMPI, ASPN, PAPLN and CHSY1 genes, which have in common to be modulated in the same way, in particular to be overexpressed in hyperpigmentary spots. Another particular combination is that consisting of genes ECM1, HS3ST6 and FLRT2, which have in common to be modulated in the same way, in particular to be under-expressed in hyperpigmentary spots. Other combinations are also conceivable within the meaning of the present invention, in particular combinations comprising at least one of EFEMP1, ASPN, PAPLN and CHSY1; and at least one of ECM1, HS3ST6, FLRT2.

The 7 genes of the invention have in common that they belong to the family of extracellular proteoglycans and glycoproteins. Any of the preferred specific gene combinations or subgroups related to this aspect of the invention are also preferred for the other aspects of the invention. The implementation of the method according to the invention leads to the conclusion that the supposed or observed spot is a hyperpigmentary spot if the level of expression is higher in the skin resulting from the stain, or in the skin sample resulting from the stain, relative to the level in the adjacent uninjured skin, or in the adjacent uninjured skin sample, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSYI, and - inferior in the stained skin, or in the skin sample from the stain, relative to the level in the adjacent uninjured skin, or in the uninjured adjacent skin sample, if the gene is selected from ECM1, HS3ST6 and FLRT2. In fact, the present inventors have demonstrated the overexpression of the EFEMPI, ASPN, PAPLN and CHSYI genes in the skin resulting from hyperpigmentary stain, in particular of actinic lentigo, relative to the level of expression in the adjacent non-injured skin. They also demonstrated the under-expression of the ECMI, HS3ST6 and FLRT2 genes in hyperpigmentary stain-like skin, particularly actinic lentigo, relative to the level of expression in the adjacent uninjured skin. Conversely, the implementation of the method according to the invention leads to the conclusion that the supposed or observed spot is a hypopigmentation spot if the level of expression is: - lower in the skin resulting from the stain, or in the skin sample from the stain, relative to the level in the adjacent uninjured skin, or in the adjacent uninjured skin sample, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSYI, and - 9 - superior in the skin from the stain, or in the skin sample from the stain, relative to the level in the adjacent non-damaged skin, or in the adjacent skin sample, if the gene is chosen among ECM1, HS3ST6 and FLRT2. By higher or lower is meant a difference in expression levels that is statistically significant, superior to noise, and reproducible. For example, the difference in level of expression is at least 10%, that is, if the level of expression of a gene of the invention in the non-injured skin is set at 1, the modulation rate is at least 1.1 for a gene overexpressed in the lesion skin and at most 0.9 for a gene that is under-expressed in the lesional skin.

Preferably, the method according to the invention is implemented with at least two genes, one belonging to the category of genes overexpressed in hyperpigmentary spots, and under-expressed in hypopigmentary spots, and the other belonging to the category of genes modulated in a strictly inverse way. Preferably, the method is implemented with at least three genes: two genes selected from EFEMPI, ASPN, PAPLN and CHSYI and a gene selected from ECM1, HS3ST6 and FLRT2, modulated in contrast to the first two in pigment spots. Preferably, in the context of this method of characterization, the level of expression of one of the genes of the invention is compared within the skin of a Caucasian-type individual. Preferably, said individual is at least forty years old, preferably at least fifty years, or even sixty years old. The individual considered, in the context of the present invention, is preferably female. As previously detailed, the level of expression of one or more genes of the invention can be compared within the skin sample of said individual. Furthermore, the present inventors have also demonstrated the differential modulation of other dermal genes between skin from a pigment spot and from the non-damaged skin, preferably adjacent. The inventors have in particular demonstrated the modulation of the following dermal genes, linked to the extracellular matrix: TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDCI genes, encoding proteins involved in the signaling pathway TGF-RSMAD; - Genes MXRA5, LYZ, CTSL2, PLAU and TIMPI coding for proteins related to matrix remodeling, genes LEPREL1, PLOD2, COL6A3 and CRTAP coding for collagens, components of the extracellular matrix, and more particularly filamentous stroma collagens and for molecules associated with the biosynthesis and assembly of collagens; LAMC1, LAMB3 and LAMAS genes encoding laminins, adhesive proteins of the extracellular matrix; FRASI, MATN2 and DST genes encoding matrix proteins associated with the basement membrane region; ITGA2, ITGAV and ITGB1 genes encoding integrins involved in cell binding to the extracellular matrix; - ACTNI gene coding for actin, a component of the extracellular matrix. Therefore, the method of characterization according to the present invention also comprises the comparison of the levels of expression within the skin resulting from said spot and within the non-damaged skin, preferably adjacent, of at least one first dermal gene. of the family of proteoglycans and extracellular glycoproteins selected from the list consisting of the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, preferably from EFEMPI, ECM1, ASPN, HS3ST6, PAPLN and CHSY1; and at least one second gene selected from the list of the following genes: TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, SOSTDC1, MXRA5, LYZ, CTSL2, PLAU, TIMP1, FRASI, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMCI, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1; for example, the second gene is chosen from the list of the following genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDC1, or from the list of the following genes: MXRA5, LYZ, CTSL2, PLAU and TIMP1 , or even among the list of the following genes: FRASI, LEPRELI, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGB1 and ACTNI.

Preferred genes in the second list of dermal genes are the TGFBR2, TGFBI, BMP2, SMAD3, THBS2 and TGFBR3 genes, the MXRA5, LYZ, CTSL2, PLAU and TIMP1 genes as well as the FRASI, LEPRELI, MATN2, DST genes, PLOD2 and ITGA2. Preferably, the second gene is chosen from the TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDCI genes and preferably from the TGFBR2, TGFBI, BMP2, SMAD3, THBS2 and TGFBR3 genes. Alternatively, the second gene is selected from the genes MXRA5, LYZ, CTSL2, PLAU and TIMP1. According to yet another embodiment, the second gene is chosen from the FRASI, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTNI genes, and preferably among the FRASI genes. , LEPRELI, MATN2, DST, PLOD2 and ITGA2.

Alternatively, the second gene may be chosen from LEPREL1, PLOD2, COL6A3 and CRTAP, or from LAMCI, LAMB3 and LAMA3, or from among FRASI, MATN2 and DST, or else from ITGA2, ITGAV and ITGB1, or else be ACTNI. According to one particular embodiment, the method comprises the comparison of the expression levels of at least 3 distinct genes, one chosen from the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSYI and FLRT2 genes, a second one chosen from the TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDC1 genes and a third one selected from the MXRA5, LYZ, CTSL2, PLAU and TIMP1 genes. According to yet another embodiment, the method comprises the comparison of at least 4 distinct genes, the first three being chosen as described previously and the fourth in the list consisting of FRASI, LEPRELI, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1. All of the gene combinations described above are also preferred combinations within the scope of other aspects of the invention.

If an additional gene, or more, is selected from the genes THBS2, TGFBI, BMP2, SMAD3, TGFBR2, TGFBR3, SEMA5A, SMAD7, SOSTDCI, MXRA5, LYZ, CTSL2, PLAU, TIMP1, FRAS1, LEPREL1, MATN2, DST, PLOD2 , ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1, then the characterization method leads to confirm a hyperpigmental spot if the level of expression is higher in the skin resulting from the stain, or in the skin. skin sample from the stain, relative to the level in the adjacent uninjured skin, or in the uninjured adjacent skin sample, if the gene is selected from THBS2, TGFBI, BMP2, SMAD3, TGFBR2, TGFBR3, SEMA5A , SMAD7, MXRA5, LYZ, PLAU, TIMPI, FRAS1, LEPREL1, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1, and lower in the skin from the stain, or in the skin sample from the stain, relative to the level in the adjacent uninjured skin, or in the adjacent skin sample no n injured, if the gene is selected from SOSTDCI, PLOD2 and CTSL2. Conversely, the evaluation method confirms a hypopigmentation spot if the level of expression is: - lower in the stained skin, or in the skin sample resulting from the stain, by level ratio in the adjacent uninjured skin, or in the adjacent uninjured skin sample, if the gene is selected from THBS2, TGFBI, BMP2, SMAD3, TGFBR2, TGFBR3, SEMA5A, SMAD7, MXRA5, LYZ, PLAU, TIMP1 , FRAS1, LEPREL1, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGB1 and ACTN1, and higher in the skin from the stain, or in the skin sample from the stain, relative to the level in the adjacent uninjured skin, or in the adjacent uninjured skin sample, if the gene is selected from SOSTDCI, PLOD2 and CTSL2. The described method is also a test method for predicting the formation of cutaneous spots in a subject. According to this embodiment, the level of expression of at least one, and preferably more than one, gene of the invention is compared in a skin sample, to its level of expression in normal skin. A significant modulation of the level of expression relative to the normal skin makes it possible to conclude that the skin of the test subject is prone to the formation of cutaneous spots. By normal skin, it may be either the skin of the same subject, in a body area notoriously devoid of spots, for example areas not exposed to solar radiation, or areas not prone to the formation of pigment spots. It may also be the average level of expression of said genes, in the skin of persons without spots and preferably having the same skin type as the test subject. The normalization genes described above may be used to normalize the expression levels of the genes of the invention.

The present invention also relates, in a second aspect, to a method for evaluating the effectiveness of a treatment of pigmentary spots or irregularities, using the signature demonstrated by the inventors. The evaluated treatment can be a treatment aiming at the attenuation of pigment spot or any other modulation of the pigmentation, in particular to standardize the complexion, to homogenize the color of the skin or to fight against the dyschromias. According to a first implementation, this evaluation method comprises a step of comparing the levels of expression in the skin resulting from a pigment spot, before and after treatment, of at least one dermal gene chosen from the genes of the invention, namely EFEMPI, ECMI, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2.

According to this evaluation method, the comparison of the expression levels of the selected gene or genes is carried out within the skin resulting from a pigment spot, or within a corresponding sample, before and after treatment. There is therefore no comparison to a level of expression within healthy non-injured skin. As for the characterization method according to the first aspect of the invention, the expression levels are advantageously standardized using the expression levels of the genes encoding the ribosomal protein L13a (RPL13A), beta-2-microglobulin (B2M), ribosomal protein S9 (RPS9), ribosomal protein S28 (RPS28) and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH). By the evaluation method as described, a given treatment is considered effective for the treatment of a hyperpigmental spot if the level of expression is: lower after treatment compared to the level of expression before treatment, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSY1, and higher after treatment compared to the level of expression before treatment, if the gene is selected from ECMI, HS3ST6 and FLRT2.

Conversely, by the evaluation method of the invention, a given treatment is considered effective for the treatment of hypopigmentation spots when the level of expression is: higher after treatment compared to the level of expression before treatment, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSY1, and lower after treatment compared to the level of expression before treatment, if the gene is selected from ECMI, HS3ST6 and FLRT2. A treatment will be considered as having no effect if the expression levels of the chosen gene, before and after treatment, are substantially identical, or if the differences observed are not significant. When the expression levels of more than one gene are compared, the treatment is considered effective for the treatment of a spot or pigment irregularity if, for the majority of the genes tested, and preferably for the all genes tested, taken individually, the treatment is considered effective. For the other genes chosen, the treatment should preferably have no effect, but not have the opposite effect. According to another embodiment, the method for evaluating the efficacy of a treatment of cutaneous pigment spots includes the characterization of a spot or pigment irregularity according to the method of the invention, before and after treatment, and the comparison differences in expression levels observed between damaged skin of the spot or pigment irregularity and healthy skin. According to this implementation of the evaluation of the effectiveness of a treatment, the treatment is considered effective if the difference between the expression levels of the gene (s) selected in the damaged skin resulting from the stain compared to the healthy skin, preferably adjacent, is less after treatment than it was before treatment. When the expression levels of more than one gene are compared, it is preferably concluded that the treatment is effective when, for the majority of the genes chosen, and preferably for all the genes chosen, taken individually, can conclude to an effective treatment. Preferably, the comparison of the expression levels of the selected gene or genes is performed on skin samples taken from the pigment spot. The treatment considered, evaluated by the method of the invention, is not limited to a particular type of treatment. It may be a treatment with a chemical molecule, an active ingredient, a natural extract, in particular an essential oil, a nucleic acid, especially an RNAi, a protein complex or any other molecule or combination of molecules. It can also be a treatment by a physical means or waves, including electromagnetic waves. It is preferably a topical treatment, but it is also envisaged to evaluate the effectiveness of treatments administered orally, by injection, or by any other means of administration. The tested treatment can aim to attenuate or make disappear a cutaneous spot, to modulate the pigmentation of the skin, to standardize the complexion, to homogenize the color of the skin or to attenuate the dyschromias. Particularly preferred treatments in the context of this invention are cosmetic treatments, more particularly cosmetic topical treatments. In this case, the pigment spot considered is a patches or non-pathological pigment irregularity, for example it is an actinic, solar or senile lentigo. By the methods of the invention, it is also possible to evaluate the effectiveness of the combination of several treatments. It is indeed possible to evaluate combinations that best restore the expression levels of one, more or all of the genes of the invention, as expressed in non-damaged skin. By the evaluation methods described above, it is possible to evaluate the effectiveness of a new treatment envisaged, or else to quantify or qualify the effectiveness of existing treatments against age spots, which they are hyperpigmentary or hypopigmentary. In this way, it is also possible to envisage combinations of treatments that can be particularly effective, synergistic or complementary. As explained for the characterization methods according to the first aspect of the invention, it is preferably compared the expression levels of more than one gene, preferably at least two, three, five, six, or of the 7 genes of the invention. Particularly preferred genes or gene combinations have already been explained with respect to the first aspect of the invention; the same genes or combinations are preferred in this aspect. In particular, it is particularly preferred that the selected gene be one of the EFEMP1, ECM1, ASPN, HS3ST6, PAPLN and CHSY1 genes, and any two, two or three to three of the genes in this list are particularly preferred, as well as the combination consisting of the EFEMPI, ASPN, PAPLN and CHSY1 genes, as well as the combination consisting of ECM1, HS3ST6 and FLRT2 genes. Furthermore, because of the complementary results obtained by the inventors concerning other dermal genes whose level of expression is modulated within the pigment spot, the evaluation methods as described are preferably carried out with at least a gene selected from the EFEMPI, ECMI, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, and even preferably from the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN and CHSYI genes, and at least one second gene selected from among the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, SOSTDCI MXRA5, LYZ, CTSL2, PLAU, TIMP1, FRAS1, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV , ITGBI and ACTN '[. Alternatively, the second gene may be chosen from the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDC1 or among the MXRA5, LYZ, CTSL2, PLAU and TIMPI genes or among the FRASI genes, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGB1 and ACTN1. Preferred genes within the dermal genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDCI are the TGFBR2, TGFBI, BMP2, SMAD3, THBS2 and TGFBR3 genes. Preferred genes within the dermal genes FRAS1, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGB1 and ACTN1 are the FRAS1, LEPRELI, MATN2, DST, PLOD2 and ITGA2 genes. If an additional gene, or more, is selected from the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, SOSTDCI, MXRA5, LYZ, CTSL2, PLAU, TIMPI, FRAS1, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, 1TGBI and ACTN1, so the evaluation method leads to consider an effective treatment for the treatment of hyperpigmentary spots if the level of expression is lower after treatment relative to the level of expression before treatment, if the gene is selected from TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, MXRA5, LYZ, PLAU, TIMPI, FRAS1, LEPREL1, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGB1 and ACTN1, and - higher after treatment compared to the level of expression before treatment, if the gene is selected from SOSTDCI, PLOD2 and CTSL2. Conversely, the evaluation method leads to consider an effective treatment for the treatment of hypopigmentation spots if the level of expression is: - higher after treatment compared to the level of expression before treatment, if the gene is selected from TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, MXRA5, LYZ, PLAU, TIMPI, FRAS1, LEPRELI, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMCI, LAMB3, LAMA3, ITGAV, ITGBI and ACTNI, and - lower after treatment compared to the level of expression before treatment, if the gene is selected from SOSTDCI, PLOD2 and CTSL2.

The skin sample preferably comes from a human being of Caucasian type, preferably at least forty years old, preferably at least fifty years, or even at least sixty years old. Preferably, in the context of the present invention and in particular for the evaluation method described, it concerns the treatment of hyperpigmentary spots, and most preferably of actinic, solar or senile lentigines. The method for evaluating the efficacy of a treatment according to the present invention is preferably carried out in vitro or ex vivo. It can also be implemented in vivo. It is desirable that the skin sample before treatment and after treatment be taken from the same pigment spot, or a very close pigment spot if the size of the stain makes it difficult to obtain samples beforehand. and after treatment. The present invention also relates to an in vitro method for evaluating the efficacy of a treatment of pigment spots; such a method comprises the comparison, before and after treatment, of the level of expression in a representative cell model of the skin, of at least one dermal gene of the family of proteoglycans and extracellular glycoproteins selected from the list consisting of the EFEMP1 genes. , ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2, or the level of expression or activity of the expression product of said selected gene. The cellular model can be of any type considered appropriate by those skilled in the art. It may be in particular mono or co-cultured cell models, or three-dimensional models of reconstructed skin, or ex-vivo cultured skin. There are also cell models representative of pigment spots, more particularly of actinic lentigines, which can be used in the context of this method. Such cell models do not need to mimic pigment spots (or lentigo) in their entirety but must mimic biological events, morphological or pigmentary features observed in pigmented spots, including lentigo. Such in vitro models are well known to those skilled in the art. According to a preferred implementation of the in vitro method described above, it comprises the comparison of the expression levels of at least two genes, preferably at least three, five or six genes of the invention, such as explained for the other evaluation methods according to the invention. Particularly preferred genes are the EFEMP1, ECM1, ASPN, HS3ST6, PAPLN and CHSY1 genes. Likewise, as explained for the other evaluation methods, they are preferably used with at least two genes, one being selected from the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, and preferably among the genes EFEMPI, ECMI, ASPN, HS3ST6, PAPLN and CHSY1, and the second being chosen from the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, SOSTDC1, MXRA5, LYZ, CTSL2, PLAU, TIMP1, FRASI, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1, preferably among the TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 genes and SOSTDCI or among the genes MXRA5, LYZ, CTSL2, PLAU and TIMP1, or even among the genes FRASI, LEPRELI, MATN2, DST, PLOD2 and ITGA2. All the specific gene combinations described with respect to other aspects of the invention are also preferred in this aspect.

In addition, by means of these evaluation methods, it is possible to promote a treatment with consumers, by highlighting the results obtained with this treatment in the efficacy evaluation methods described in the present invention. The present invention therefore also provides a method for recommending a product by signaling its effect in a test protocol consisting of a method of evaluating the efficacy as described above. The invention therefore also relates to a method for the promotion of a cosmetic product or cosmetic treatment consisting in reporting an efficacy, action or property of said product or treatment, demonstrated by at least one method operated as described above. Such promotion of the product can be done by any communication channel. It may be made by the seller, directly on the point of sale, by radio and television, particularly in the context of commercials. It may also be done through the press, or through any other document, especially for advertising purposes (prospectus). It can also be done via the Internet, or any other appropriate computer network. It may also be made directly on the product, in particular on its packaging or on any explanatory note that may be associated with it. The present invention also relates to a method for screening molecules for the treatment of cutaneous pigment spots comprising the implementation of one of the evaluation methods described above for determining the effectiveness of a treatment based on this molecule.

According to another aspect, the present invention also relates to a cosmetic method for the treatment or prevention of non-pathological cutaneous spot or skin irregularity of the skin, comprising the modulation of the level of expression or the activity of a skin dermal gene. the family of proteoglycans and extracellular glycoproteins, wherein said gene is selected from the list consisting of EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes. Non-pathological skin pigment spots are benign spots, the removal of which is desirable only for aesthetic reasons and not for therapeutic reasons. Pigmentation irregularities include imperfections at the pigment level rendering the complexion uneven or the color of the skin uneven. The present inventors have shown the important role of genes of the invention within the dermis at the level of pigment spots, and in particular the link between dysregulation of the level of expression of these genes and appearance of pigment spots. As a result, suspending or reducing the modulation of these genes may make it possible to reduce or abolish the deregulation observed and thus make it possible to restore a situation at the level of the extracellular matrix that is compatible with the absence of a pigment spot, with therefore a uniform complexion and homogeneous skin color ..

For the same reasons as explained with regard to the other aspects of the invention, it is preferable to choose more than one gene within the genes of the invention, for example at least two genes, at least three, five, six . According to one embodiment, the purpose of the cosmetic method is to modulate the level of expression of the entirety of the genes of the invention. The cosmetic method according to the invention aims to restore expression levels close to those observed in healthy skin, adjacent for example of a pigment spot. Particularly preferred genes are the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN and CHSY1 genes. According to a preferred embodiment, said pigment spot is a hyperpigmentary spot, for example an actinic, senile or solar lentigo. In such a case, the modulation sought in the cosmetic methods according to the invention is a total, partial or temporary inhibition of the expression of at least one gene chosen from the EFEMPI, ASPN, PAPLN and CHSY1 genes or else a optionally increasing, temporarily, the expression of at least one gene chosen from the genes ECM1, HS3ST6 and FLRT2. Preferably, the inhibition is not a total but partial inhibition, tending to decrease the level of expression of the selected gene without inhibiting its expression entirely. According to another embodiment, said pigment spot is a hypopigmentary spot. In such a case, the desired modulation is the reverse of the previous situation, in particular such a method is intended to increase the expression of at least one gene chosen from the EFEMPI, ASPN, PAPLN and CHSY1 genes, or to inhibit or to reduce the level of expression of at least one gene selected from the genes ECM1, HS3ST6 and FLRT2. By increasing or decreasing the level of expression, it is included increasing or decreasing the level of transcription of said genes, and increasing or decreasing the level of translation of said genes, as well as increasing or decreasing the level of transcription. activity of the proteins encoded by these genes. Preferably, concomitantly with the modulation of the level of expression sought for one of the genes of the invention, a cosmetic method according to the invention preferably also comprises the modulation of at least one other dermal gene, chosen from the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, SOSTDCI, MXRA5, LYZ, CTSL2, PLAU, TIMP1, FRAS1, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMCI, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1. Preferred genes within this second list of dermal genes are the TGFBR2, TGFBI, BMP2, SMAD, THBS2 and TGFBR3 genes; the genes MXRA5, LYZ, CTSL2, PLAU and TIMP1; and FRAS1, LEPRELI, MATN2, DST, PLOD2 and ITGA2 genes. The modulations applied, if it is the treatment of a hyperpigmentation spot, are the decrease of the level of expression for the genes TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, MXRA5, LYZ, PLAU, TIMP1, FRAS1, LEPRELI, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1 and the increase in the level of expression for the SOSTDCI, PLOD2 and FLRT2 genes. In the case of hypopigmentation spot treatment, the applied modulations are reversed. A cosmetic method according to the present invention thus comprises the application of a product, in particular chemical molecule, natural extract, active agent, nucleic acids, peptides, or a treatment modulating the level of expression or the activity of the product of expression of at least one of the dermal genes of the invention. If it is a product, it is preferably applied topically. Preferably, the modulation is effected by using a modulator of one of the genes of the invention. Such modulators are described in example 3 and in table 3. For example, a cosmetic method according to the invention will advantageously comprise the application of a compound chosen from letrozole and anastrozole, or a combination of these modulators. . Moreover, a cosmetic method according to the invention is advantageously used after the characterization of the pigment spot that it is desired to treat by a method according to the first aspect. Indeed, this first step makes it possible to characterize the spot and thus to detect the genes whose level of expression is strongly modulated between the area of the spot and a non-damaged area, preferably adjacent. It is then possible to adapt a treatment which makes it possible to act on the gene or genes of the invention which are modulated differentially within this spot, by specifically applying modulators for said genes.

Whatever the treatment considered, the cosmetic method according to the invention may also comprise the application of one or more additional active compounds intended to enhance the desired effects, for example any substance described as depigmenting, keratolytic and / or desquamating agents. antioxidants, UV chemical or physical sunscreens, anti-inflammatory and / or soothing agents, deoxyribonucleic acids and their derivatives. The cosmetic method according to the present invention is also applicable in the case of the prevention of the appearance of pigment spots or other irregularities of the complexion or the color of the skin, and in particular of hyperpigmented spots such as the actinic lentigo. Indeed, the various data obtained by the inventors and detailed in the experimental part reveal that the damage to the extracellular matrix, in particular to its components proteoglycans and extracellular glycoproteins, through the genes identified by the inventors are likely to occur upstream , before the appearance of the spots. It may be thought that the sequence of biological events in hyperpigmentary spots may be as follows: 1) alteration of the dermis (due to the modulation of the expression of the genes identified in this application) which leads to 2) modification of the epidermis with epidermal crest formation in the dermis which leads to 3) an increase in the length of the dermo-epidermal junction and the formation of complex networks leading to 4) an increase in the melanic charge The present invention also relates to the use of a modulator of the expression level or the activity of the expression product of at least one dermal gene chosen from the list consisting of the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, for a cosmetic application in the treatment of non-pathological skin pigment spots or more generally in the modulation of skin pigmentation.

For the treatment of hyperpigmentary spots, the modulator that is used is an inhibitor of at least one gene selected from EFEMP1, ASPN, PAPLN and CHSYI, or else an activator of at least one gene selected from ECM1, HS3ST6 and FLRT2. . Preferably, the inhibitor is a partial inhibitor leading to the decrease in the level of expression or the decrease in the activity of the expression product of said gene, without completely abolishing the expression or activity of this gene. . Conversely, for the treatment of hypopigmentary spots, the modulator used is an activator of at least one gene selected from EFEMPI, ASPN, PAPLN and CHSY1, or an inhibitor of at least one gene chosen from ECM1, HS3ST6 and FLRT2. Examples of previously known and characterized inhibitors or activators are disclosed in Example 3 of the Experimental Part. Well known modulators are also antisense molecules, siRNAs, and microRNAs.

Preferred modulators in the context of the present invention include letrozole and anastrozole. It is also conceivable to use a combination of these two modulators. Modulators as described can be used in the cosmetic methods according to the invention in combination with modulators of the TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7 and SOSTDC1 genes, or modulators of the MXRA5, LYZ genes. , CTSL2, PLAU and TIMP1, or alternatively modulators of FRAS1, LEPREL1, MATN2, DST, PLOD2, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1 genes. Preferred gene combinations have already been described. Modulators can be used in combination with other products, actives or excipients. Preferably, they are packaged in a form suitable for topical application, for example in the form of ointment, cream or ointment. The various implementations detailed in the section relating to the cosmetic methods according to the invention are applicable to the uses for the cosmetic applications described above. The modulators according to the invention can be used in particular in cosmetic applications in order to standardize the complexion, to homogenize the color of the skin or to combat dyschromias. Furthermore, according to another aspect, the present invention relates to modulators of the expression level or the activity of the expression product of at least one dermal gene chosen from the genes EFEMP1, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2, for an application in the treatment of cutaneous pigment spots, for example in the context of therapeutic treatments. Said spots may be hyperpigmentary spots, or hypopigmentary spots. Preferred modulators have already been described for the other aspects of the invention. They can be combined with other products, actives or excipients. Preferably, they are packaged in a form suitable for topical application, for example in the form of ointment, cream or ointment. In the various methods and applications according to the present invention, the pigment spots considered are preferably hyperpigmentary spots and most preferably actinic, solar or senile lentigines. The methods and applications according to the invention are based on the demonstration by the inventors of a signature of such pigmented spots. This signature is characterized by the fact that it can be constituted by the whole of the list or a part of the genes mentioned. The present invention also relates to the use of this signature as a new method of selection and prediction of the actinic lentigo through deficiencies in its biological functions. This new method is based on studying the level of expression of all or part of the genes described in the present invention in a hyperpigmented lesion versus an adjacent non-injured skin. This invention is also part of the treatment of the actinic lentigo, through the use of these genes as a molecular signature of the differences in gene expression existing between a lesion and the adjacent healthy skin. This signature is also an obvious advantage to determine the choice of the appropriate treatment and to measure the effect of a product (active, molecule, natural extract), but also of a process (light, injection, orally) which is beneficial on the skin. The present invention indeed makes it possible to evaluate the efficacy of a product or process intended to treat the actinic lentigo by modulating at the level of the lesion the expression of all or part of the genes described so that their profile of expression is close to that of healthy skin. The invention also consists in a method of screening inhibition or prevention factors of actinic lentigines. It consists in evaluating compounds on their ability to inhibit or increase the expression of the mentioned genes and the expression or activity of the protein products of said genes and to select them as factors making it possible to prevent or treat the actinic lentigo. The verification of the effectiveness of the compounds can be carried out on mono or co-cultured cell models, or tri-dimensional models of reconstructed skin, or skin ex vivo, or in vivo. The subject of the invention is also the use of compounds modulating the expression of the genes identified among the biomarkers of the actinic lentigo, to prevent or correct the lesion in order to find a normal state of the skin, that is to say to recover an expression close to the expression of healthy non-injured skin. In particular, compounds acting on the proteins identified to prevent or treat pigmentary dyschromias (hyperpigmentation or hypopigmentation) have never been proposed. Such compounds exist and are reported in Table 3 of Example 3. The chosen agents are in particular negative modulators of overexpressed proteins of the family of proteoglycans and extracellular glycoproteins or positive modulators of the under-expressed proteins. Among the negative modulators of the proteins of the family of proteoglycans and extracellular glycoproteins mention may be made in particular of inhibitors of synthesis, and / or of the secretion and / or activator of the degradation of the proteins found overexpressed in the lentigo. In contrast, among the positive modulators, mention may be made of synthetic stimulants, secretion inducers or inhibitors of the degradation of proteins expressed in the lentigo.

Experimental part: Example 1: Transcriptional study A comparative study of the gene expression profile of the skin resulting from an injury of actinic lentigo (PL) and adage free skin (PN) was performed. The aim of this study is to identify relevant, reproducible and significant markers reflecting the alterations associated with actinic lentigo formation, in order to use them as targets for effective treatments, or as biomarkers to analyze the efficacy of a treatment. given. Briefly, 15 healthy female volunteers were recruited to participate in a full genome transcriptomic study (Affymetrix chips). For each volunteer, an actinic lentigo lesion was diagnosed on the back of the hand and the diagnosis of actinic lentigo was verified by epiluminescence. This examination allows 1 °) to verify the clinical diagnosis of the lesion (actinic lentigo exclusively) according to the pattern criteria of the dermal-epidermal junction (pigmented network structure, "fingerprint-like structure") to differentiate ephelides (absence of pigmented network structure, homogeneous pigmentation and areas of "moth-eaten edges") and flat seborrheic keratoses (multiple milia-like cysts or pseudocysts, areas of "moth-eaten edges", pseudofollicular openings and fingerprint-like patterns) [Menzies et al ; Stolz et al; Marghoob et al] 2 °) to delineate homogeneous areas in terms of structure / pattern within these lesions where cutaneous biopsies will be made, 3 °) to establish a phenotypic score based on a quantitative image analysis with the specific software developed on Matlab® (SQA software, CMLA, ENS Cachan, UMR CNRS 8536). A 3mm biopsy centered on the lesion was performed as well as a biopsy of identical size on an adjacent non-injured skin area. The total RNAs of these samples were extracted and amplified. Probes were generated for hybridization on Affymetrix chips. Gene expression profiles were generated for each of the biopsies (2 biopsies per volunteer), and a comparative analysis was performed between PN and PL by volunteer and on all volunteers. The statistically differentially expressed genes (geometric mean of patients) were compiled into lists and grouped by functional families. Surprisingly and unexpectedly, the inventors found a differential expression for several hundred genes between PN and PL. A list of 437 genes has been constructed and represents a broad molecular signature of the actinic lentigo lesion. Of the 437 genes identified, 169 genes were found to be positively regulated ("upregulated") in the "actinic lentigo" lesion compared to healthy skin while 269 genes were downregulated in the actinic lentigo ("upregulated"). regulated clown "). All these genes have been subdivided into several functional families.

Among the functional families or biological processes identified, the inventors have surprisingly found a family of genes reflecting at the molecular level a dysfunction of the extracellular matrix and the dermo-epidermal junction in the actinic lentigo. These genes, grouped in this functional family named "Extracellular Matrix" have never been previously described as associated with actinic lentigo and are listed below and in Tables 1 and 2:

Over-expressed genes in actinic lentigo compared to healthy skin TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, EFEMPI, ASPN, PAPLN, CHSY1, MXRA5, LYZ, PLAU, TIMPI, FRASI, LEPREL1, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMC1, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1. Under-expressed genes in actinic lentiqo compared to healthy skin SOSTDCI, ECMI, HS3ST6, FLRT2, CTSL2 and PLOD2.

These genes encode components of the dermis or proteins involved in the synthesis of extracellular matrix components, related to the renewal or remodeling of this conjunctive matrix, as well as genes encoding matrix proteins associated with the dermal-epidermal junction and the area of the basement membrane. This family also contains genes related to the TGFbeta pathway involved in the synthesis of extracellular matrix components. The genes of this family are mainly expressed in the actinic lentigo. This family of genes is quite original in a pigment disorder and implies a preponderant role of the stroma in the actinic lentigo.

Table 1: list of genes of the "extracellular matrix" family found overexpressed in the actinic lentigo Subfamily Denominated name Full name Pathway I function nation accession modulation TGFbISMAD THBS2 NM_003247 thrombospondin 2 3.41 TGFBI NM 000358 transforming growth factor, beta - 2,22 induced, 68kDa BMP2 NM_001200 bone morphogenetic protein 2 2,0330 -24- Subfamily Denomi- Number Full name Rate of path / function nation accession modulation SMAD3 NM_005902 SMAD family member 3 1.76 Transforming growth factor, beta TGFBR3 NM 003243 1.68 - receptor II I D50683 TGFb 1 SMAD transforming growth factor, beta TGFBR2 NM 001024847 1.61 receptor II (70180kDa) NM_003242 sema domain, seven thrombospondin SEMA5A NM_003966 repeats (semaphorin) 1.56 (semaphorin 5A, semaphorin F ) SMAD7 NM_005904 SMAD family member 7 1.52 LEPREL1 NM_018192 leprecan-like 1 2.64 Collagen COL6A3 NM_004369 collagen, type VI, alpha 3 1.90 cartilage associated protein CRTAP NM_00 6371 (LEPREL3) 1.60 laminin, gamma 1 (formerly LAMC1 NM_002293 LAMB2) 1.96 L25541 laminins NM_000228 LAMB3 laminin, beta 3 1.94 N M_001017402 N M_001127641 LAMA3 NM_000227 laminin, alpha 3 1.64 integrin, alpha 2 (CD49B , alpha 2 ITGA2 NM 002203 1 '62 - subunit of VLA-2 receptor) Integrins N M_001145000 ITGAV NM-001144999 integrin, alpha V (vitronectin receptor), 1.62 N M_002210 ITGB1 NM_133376 integrin, beta 1 1.55 MXRA5 NM_015419 matrix -remodelling associated 5 2.40 LYZ remodeling NM_000239 lysozyme (renal amyloidosis) 2.33 matrix TIMP1 NM_003254 TIMP metallopeptidase inhibitor 1 2.26 PLAID NM_002658 plasminogen activator, urokinase 1.81 -25- Subfamily Denomination- Full name Rate of pathway 1 function nation accession modulation NM_001039348 EGF-containing fibulin-like EFEMPI NM_001039349 extracellular matrix protein 1 3.86 NM_004105 (FIBULIN 3) Proteoglycans and glycoprotein ASPN NM_017680 Asporin 2.77 extracellular papilin, proteoglycan-like sulfated PAPLN NM_1 73462 glycoprotein 2.51 CHSY1 NM_014918 carbohydrate (chondroitin) synthase 1 1.50 FRAS1 NM_025074 Fraser syndrome 1 4.59 Membrane MATN2 NM_002380 matrilin 2 2.61 basal NM 001723 - DST Dystonin = BPAG1 2.24 NM_015548 NM_001130005 Actin ACTN1 NM_001130004 actinin, alpha 1 1.58 N M_001102 Table 2: list of genes of the "extracellular matrix" family found under-expressed in the actinic lentigo Subfamily Deno- Full name Route rate I function mination accession modulation Proteoglycans HS3ST6 NM_001009606 heparan sulfate (glucosamine) 3-0- 0.44 sulfotransferase 6 PLOD2 collagens NM_000935 procollagen-lysine, 2-oxoglutarate 0.45 NM_182943 5-dioxygenase 2 Proteoglycans FLRT2 NM 013231 fibronectin leucine rich 0.47 transmembrane protein 2 Remodeling CTSL2 NM_001333 cathepsin L2 (peptidase MEC 0.54 Matrix Degradation) Proteoglycans ECM1 U65932 Extracellular Matrix Protein 1 0.54 nm_004425 NM_022664 TGFb I SMAD SOSTDC NM_015464 sclerostin domain containing 1 0.62 1 (ectodin, BMP antagonist) Example 2: Material and methods 15 volunteers, women, phototypes II to IV, aged 50 to 70 years were selected. The actinic lentigines are chosen on the back of the hand, minimum size 3mm. They are characterized by Epiluminescence. The various advantages of epiluminsecence characterization are presented in Example 1. Two biopsies of 3 mm in diameter are performed on one of the hands of each patient. For each volunteer, one of the biopsies corresponds to the actinic lentigo lesion (PL) and the other to an adjacent zone of non-lesional skin (PN) (also verified in epiluminescence). The 3mm biopsies are placed, from the time of sampling, into RNA later (Qiagen reference 76106) from 16 to 24 h at 4 ° C. The next day the samples are placed at -20 ° C until the homogenization and extraction steps. Upon thawing, the samples are cut with a scalpel to facilitate homogenization, before transfer to the lysis buffer. The homogenization is carried out with a potter (Fisher Labosi ref A6391000) with RNase free polypropylene pistons (Fisher Labosi ref A1419753) allowing direct homogenization in the 1.5 ml Eppendorf tubes. The RNA was extracted with the RNeasy micro kits (Qiagen ref: 74004) following the instructions of the supplier. The quantification of the RNAs is carried out by a ribogreen assay (Molecular Probes ref R11490). Quality is validated with an Agilent 2100 bioassay analyzer which gives the ratio of 28S ribosomal RNA intensities over 18S as well as an RNA Integrity Number (RIN) which accounts for RNA degradation. Good RNA has a ratio> 1.5 and a RIN> 7. A reverse transcriptase (RT) reaction is performed to obtain the corresponding cDNAs. Two probes per sample were synthesized from 50 ng of RNAs with an amplification step. The cDNAs are labeled with fluorochromes and hybridized on affymetric DNA chips to reveal the level of expression of all the genes in the human genome. (Affymetrix U133A 2.0 U133A 2.0 type biochips containing 54,000 probes, allowing the study of the expression of 47,000 transcripts, including 38,500 characterized genes). Affymetrix Microarray suite (Mas 5.0) allows to obtain for each transcript, a detection signal. After revelation of specific hybridizations and raw data processing (extraction, subtraction of background, normalization), gene expression is compared between healthy skin and injured skin. 2 Affymetrix HG.U133 Plus 2 chips were hybridized by samples. The quality of the hybridization was carried out by the AffyPLM method (Bolstad et al., 2005) and by the PCA (Principal Component Analysis) method. Patients are retained for further analysis only if both Affymetrix chips have correct hybridization quality. For the present study, 13 of the original 15 patients could be analyzed. The realization of a transcriptomic profile of the healthy skin and the skin corresponding to the actinic lentigo made it possible to generate lists of genes differentially expressed in the two situations, and to identify biomarkers of the actinic lentigo. The lists are generated as an expression ratio between PL (damaged skin) versus PN (normal skin). The ratio representing the geometric mean of the 13 patients is retained.

Generation of lists of genes differentially expressed between damaged skin and healthy skin Steps: - Filter Affymetrix identifiers (ProbeSets): only ProbeSets that are present in the two replicates of at least one biopsy are retained. After this filter 23,968 ProbeSets are retained. Suppression of the patient effect: In order to suppress the patient effect observed in the results of the differential analyzes, the expression of each ProbeSet was divided by the geometric mean of the 4 ProbeSets values corresponding to the 4 chips. Differential analysis: it was generated by grouping the lists obtained by 2 methods, the cNMF analysis (Non Negative Matrix Factorization consensus (Lee and Seung (1999), Brunet et al (2004), Fogel et al (2007)). Fogel et al., (2008))), which identified 2638 ProbeSets (1521 induced and 1117 repressed) and Partial Least Squares Regression (PLS), which identified 610 ProbeSets modulated. The union of the 2 lists allowed to obtain a list of 3248 ProbeSets. 20 - Modulation filter: for the induced genes, selection of ProbeSets having a geometric mean of the 13 folds corrected (FC) 1.5: list of 562 ProbeSets induced. For repressed genes, selection of ProbeSets with a geometric mean of the 13 folds corrected FC e 0.67: list of 807 ProbeSets repressed. In total: 562 + 807 = 1369 ProbeSets modulated, ie 1007 ProbeSets after elimination of duplicates (1002 25 approach cNMF + 5 PLS approach) Filter on 13 patients: visualization of modulations of 1007 ProbeSets in the form of histograms and selection of modulated ProbeSets in the same direction in the 13 patients. Final list of 132 ProbeSets that differentiate lesional biopsies from non-lesional biopsies and are modulated in the same direction in the 13 patients in the study. Analysis of the list of 1007 Probe sets o Filter on the P value (5 0.00001) In order to retain only the most discriminating genes, we applied to the list of 1002 ProbeSets a filter on the P-value, P s 0.00001. After this new filter 827 ProbeSets to which are added ProbeSets from the PLS approach b list of 832 ProbeSets After searching for annotations, elimination of unannoted genes and elimination of duplicates, a list of 437 differentially expressed genes between PL and PN has been established. 169 genes are over-expressed in the LA and 269 are under-expressed. With the help of tools, Gene ontology, PubMed, Scopus gene functions are searched and genes are classified by functional families.

Example 3 Modulators There are known compounds for modulating in the desired sense the deregulated proteins in the lentigo. For the family of genes / proteins of the extracellular matrix, mention may be made of: fibrates, of which, for example, fenofibrate, which decreases the expression of SMAD3, alkaloids including the oxymatrin which decreases SMAD3, or polyphenols such as, for example, salvianolic acid B which decreases SMAD3 and TGFBR2, natural extracts including medicinal herbs such as Wen-pi-tang-hab-wuling-san which decreases SMAD3, 15 - compounds of the imidazole family of TGF- [3R1 antagonists as SB-431542 which decreases SMAD3, some miRNAs including miR183 and miR29b which decrease ITGBI, urokinase-type plasminogen activator (uPA) inhibitors such as paminobenzamidine or B428-subtituted benzo [b] thiophene-2-carboxamodine which 20 decrease the activity of PLAU, compounds of the family of phenylacetates such as NaPA which decreases expression of PLAU, - compounds of the chemical family of thiazolidinediones including for example pioglitazone which decreases BMP2 and COL6A3, compounds of the chemical family of thiazoles including, for example, GW-0742 which decreases the expression of BMP2; compounds of the tetrazole family such as Valsartan which decreases TIMP1.

Regarding the PLOD2 enzyme protein of the extracellular family sub expressed in the lentigo, the following compounds can be used to restore its level: compounds of the family of quinazolines such as Vandetanib (ZD64745 5) which increase PLOD2.

Other types of modulators may also be employed to enable correction of the expression / amount or activity of deregulated proteins. There may be mentioned: nucleic acids (preferably antisense RNA or RNAi), neutralizing antibody, electrical, light, mechanical or thermal means. For example, low intensity pulsed ultrasound (LIPUS) may be used to increase the amount or activity of PLOD2. Conversely, in the case of a hypopigmentary spot, preferred modulators will be those increasing the level of expression or activity of the proteins originating from the TGFBR2, TGFBI, BMP2, SMAD3, THBS2, TGFBR3, SEMA5A, SMAD7, EFEMPI and ASPN genes. , PAPLN, CHSYI, MXRA5, LYZ, PLAID, TIMP1, FRASI, LEPRELI, MATN2, DST, ITGA2, COL6A3, CRTAP, LAMCI, LAMB3, LAMA3, ITGAV, ITGBI and ACTN1 and those decreasing the level of expression or activity proteins derived from the SOSTDCI, ECM I, HS3ST6, FLRT2, CTSL2 and PLOD2 genes. Examples of such modulators are also listed in Table 3. Table 3. LIST OF GENE MODULATORS INVOLVED IN ACTINIC LENTIGO Subfamily 1 Name Modulator Gene / Protein TGFB / TGFBI modulation function function, transforming growth factor Powder demineralized bone powder (DBP) Increases SMAD j3-induced, 68kDa expression TGFBI BMP2, bone morphogenetic Pioglitazone Decreases expr. SMAD protein2 GW0742 Decreases expr. Cristata L flavonoid increases expr. TGFBI SMAD3, SMAD family member3 Fenofibrate Decreases SMAD expression Decreases phosphorylation Oxymatrine Salvianolic Acid B (Sa) B), component of Danshen (a traditional Chinese herb used for chronic kidney disease) antioxidant and cellular protection. SB-431542 (a specific Tj3R-1 kinase inhibitor) Wen-pi-tang-Hab-Wu-Ting-san (WHW) TGFB / TGFBR2 extract, transforming growth Salvianolic acid B (SA-B) Decreases SMAD factor, R receptor II (70180kDa) TGFB / SMAD7 expression, SMAD family member 7 Oxymatrin increases SMAD expression 3-deoxyglucosone (Advanced glycation endproduct precursor) Tetrandrin N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) Collagen COL6A3, collagen, type VI, alpha 3 Pioglitazone Decreases expression Integrin ITGB1, integrin, beta miR-183, miR-29b Decreases expression -31 - Subfamily 1 Name Modulator gene / protein Functional sense modulation LYZ remodeling, lysozyme (renal amyloidosis) Pituitary adenylate cyclase-activating polypeptide (PACAP) Increases matrix PACAP38 expression Remodeling TIMP1, Valsartan, (angiotensin II type 1 receptor blocker ARB) Decreases matrix expression metallopeptidase inhibitor 1 Plant extract of Lupinus albus LUI 0 demineralized bone powder (Demineralized bone p owder, DBP) Increases Express. PLAU remodeling, plasminogen activator, Sodium phenylacetate (NaPA) decreases matrix expression urokinase P-aminobenzamidine (Urokinase-type plasminogen activator (uPA) decreases inhibitor activity): B428 4, B392 -substituted benzo [b] thiophene-2-carboxamidines (Urokinase- plasminogen activator (uPA) inhibitor Thienopyridine SR 25989 (Angiogenesis inhibitor) esterified derivative of Increases ticlopidine, Notoginsenoside R1 expression (from PANAX notoginseng) Assimilated ASPN, Asporin letrozole, anastrozole Increases Protéoglycan expression Membrane MATN2, matrilin 2 vitamin K2 menaquinone Increases basal expression Collagen PLOD2, beta-aminopropionitrile (bAPN) Decreases expression procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 Low-intensity pulsed ultrasound (LIPUS) low-intensity pulsed ultrasound Increases expression / activity Vandetanib (ZD6474 5) Remodeling CTSL2, cathepsin L2 Derived phenylalanine decreases matrix activity

Claims (15)

REVENDICATIONS1. Method of characterizing a pigment spot CLAIMS1. A method of characterizing an apparent or suspected skin pigment spot in a human, comprising comparing levels of expression in skin samples from said stain and adjacent non-injured skin of at least one skin dermal gene. the family of proteoglycans and extracellular glycoproteins, chosen from the list consisting of the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes. The method of claim 1 comprising comparing the expression levels of at least two distinct genes, preferably at least four distinct genes selected from said list. 3. The method of claim 1 wherein said gene is selected from the list consisting of EFEMPI, ECM1, ASPN, HS3ST6, PAPLN and CHSY1 genes. The method of claim 1, wherein said stain is confirmed as a hyperpigmental spot when the level of expression is greater in the skin sample from the stain than in the adjacent skin sample without damage, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSY1, and lower in the skin sample from the stain relative to the level in the adjacent skin sample without injury, if the gene is selected from ECM1, HS3ST6 and FLRT2 . 25 5. Method according to claim 1, wherein said pigment spot is an actinic, senile or solar lentigo. 6. A method of evaluating the efficacy of a treatment of skin pigment spots, including comparing the levels of expression in a skin sample from such a spot, before and after treatment, of at least one dermal gene of the family of proteoglycans and extracellular glycoproteins selected from the list consisting of EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes. 35 7. Method according to claim 6, wherein said treatment is considered effective for the treatment of hyperpigmentary spots when the level of expression is: - lower after treatment compared to the level of expression before treatment, if the gene is selected from EFEMPI , ASPN, PAPLN and CHSY1, and higher after treatment compared to the level of expression before treatment, if the gene is selected from ECM1, HS3ST6 and FLRT2; and FR11 53534 B09403 CA / CS August 2011 - 32 - 2974371 - 33 - is considered effective for the treatment of hypopigmentary spots when the level of expression is: higher after treatment compared to the level of expression before treatment, if the gene is selected from EFEMPI, ASPN, PAPLN and CHSY1, and lower after treatment compared to the level of expression before treatment, if the gene is selected from ECM1, HS3ST6 and FLRT2. 8. In vitro method for evaluating the efficacy of a treatment of cutaneous pigment spots, comprising comparing, before and after treatment, the level of expression in a representative cell model of the skin, of at least one gene dermal of the family of proteoglycans and extracellular glycoproteins selected from the list consisting of EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, or the level of expression or activity of the expression product of said selected gene. 9. Cosmetic method for the treatment or prevention of non-pathological cutaneous pigmentary stain of human skin, comprising the modulation of the level of expression or the activity of a dermal gene of the family of proteoglycans and extracellular glycoproteins, wherein said gene is selected from the list consisting of the genes EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2, and wherein said modulation is performed through the use of an antisense molecule, a siRNA or a microRNA. The method of claim 9, wherein said method comprises modulating at least two genes, preferably at least four distinct genes, selected from the list consisting of EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2. 11. The method of claim 9, wherein said pigment spot is a hyperpigmentary spot, preferably an actinic, solar or senile lentigo, and wherein said modulation is an inhibition if the gene is selected from EFEMPI, ASPN, PAPLN and CHSY1; and an increase in expression level or activity if the gene is selected from ECM1, HS3ST6 and FLRT2. 12. Use of a modulator of the level of expression or the activity of the expression product of at least one dermal gene chosen from the list consisting of the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, for a cosmetic application in the treatment of non-pathological skin pigment spots, wherein said modulator is selected from an antisense molecule, siRNA, microRNA, letrozole and anastrozole. The use of claim 12, wherein said modulator is letrozole or anastrozole. FR11 53534 B09403 CA / CS August 2011- 34 - 14. Modulator of the level of expression or the activity of the expression product of at least one dermal gene chosen from the list consisting of the EFEMPI, ECM1, ASPN, HS3ST6, PAPLN, CHSY1 and FLRT2 genes, for an application in the treatment of cutaneous pigment spots, wherein said modulator is selected from an antisense molecule, an siRNA, a microRNA, letrozole and anastrozole. 15. Modulator according to claim 14, chosen from letrozole and anastrozole. FR11 53534 B09403 CA / CS August 2011