EP2276455A2 - Use of k1f13a and ap-1 inhibitors for inhibiting melanogenesis - Google Patents

Abstract

The present invention relates to novel pharmaceutical or cosmetic compositions comprising at least one inhibitor of a subunit of the AP-1 adaptor complex, of a kinesin which interacts with AP-1, in particular Kif13A, or of the interaction between a subunit of the AP-1 adaptor complex and said kinesin, and also to the use thereof for the manufacture of a medicament for use in the treatment of pigmentary disorders and as a depigmenting agent.

Description

 Novel compositions inhibiting melanogenesis and their uses

The present invention provides compositions for reducing the synthesis of melanin pigments in melanocytes and uses thereof.

Technological background of the invention

In humans, pigmentation results from the synthesis and distribution of melanin pigments, especially in the skin, hair and fur and the pigment epithelium of the iris. Thus, the color of the skin, hair and eyes depend mainly on the types of pigments present and their concentrations. This pigmentation is regulated by many internal or external factors, for example, exposure to ultraviolet.

Melanins are macromolecules produced by melanocytes by addition or condensation of monomers formed from tyrosine (eumelanin) or tyrosine and cysteine (pheomelanin). The mechanism of melanin synthesis, or melanogenesis, is particularly complex and involves different enzymes, the main ones being tyrosinase and tyrosine-associated protein (Tyrp-1). During melanogenesis, these enzymes catalyze, in particular, the conversion of tyrosine to DOPA (dihydroxyphenylalanine) and then to DOPAquinone. From this molecule, two metabolic pathways will allow the synthesis of either eumelanin or pheomelanin.

Melanogenesis occurs in specialized intracellular organelles contained in melanocytes: melanosomes. Although melanosomes are among the first cellular organelles to be described morphologically (Seiji et al., 1963), their protein composition and biogenesis remain relatively unknown.

The maturation of the melanosome can be segmented into four stages based on morphological criteria. Stage I corresponds to a compartment delimited by a membrane with a variable quantity of intraluminal membranes. Stage II is an ellipsoidal structure with characteristic striations of a protein nature. These striations play an important role in the concentration of melanin, in the elimination of toxic synthetic intermediates and in facilitating the transfer of melanin to keratinocytes (Seiji et al., 1963). Melanin is detected from stage III and in the form of electron-dense deposits along the striations. Stage IV is an electron-dense structure in which internal striations are no longer visible. This stage corresponds to the mature melanosome ready to be transferred to the keratinocytes (Van

Den Bossche et al, 2006).

During the process of biogenesis, the "pigmented" mature melanosome (stage III and IV) is obtained by adding key enzymes of melanin synthesis and effectors necessary for its transport to the periphery (Raposo et al., 2001) . The enzymes involved in melanogenesis are therefore synthesized in the Golgi apparatus and transferred to pre-melanosomes. The mechanisms involved in this transfer are still relatively unknown. This type of transfer requires, in particular, the participation of adaptive protein complexes (APs) which are heterotetramers whose role is to recruit the enzymes into the transport vesicles. There are four of these complexes, named AP-I to AP-4. The inventors have previously demonstrated that the AP-3 complex is involved in the transfer of tyrosinase to melanosomes. However, AP-3 deficiency does not abolish pigmentation and does not affect Tyrp-1 trafficking. They also observed that the AP-I adapter complex was able to interact with amino acid sequences of the tyrosinase and Tyrp-1 cytosolic domains without elucidating the exact function of this complex in melanogenesis (Theos and al., 2005). At the same time, it has also been shown that a kinesin, named Kif13A, is able to interact with an AP-I subunit (Nakagawa et al., 2000). This interaction was observed in cell lines lacking a melanosome. The existence of such interaction in melanocyte lineages as well as its role in melanogenesis are therefore not determined.

Malfunction of melanocytes may cause pigmentation abnormalities. Hypopigmentation can be caused by depigmenting diseases, especially albinism and vitiligo. Conversely, local hyperpigmentations may result from certain melanocytic disorders such as idiopathic melasmas or hyperactivity and benign melanocyte proliferation causing, for example, senile pigment spots (actinic lentigo). Hyperpigmentation can also be of accidental origin and caused for example by photosensitization or post-injury healing. These hyperpigmentations can be treated with depigmenting substances administered topically. A depigmenting molecule acts on the melanocytes of the epidermis and interferes with one or more stages of melanogenesis. Known depigmenting substances include hydroquinone and its derivatives, ascorbic acid and its derivatives, placental extracts, kojic acid, arbutin, iminophenols (WO 99/22707), the combination of carnitine and quinone (DE 19806947), amide derivatives of amino phenol (FR 2 772 607), and benzothiazole derivatives (WO 99/24035).

These substances may have various disadvantages due in particular to their instability, the need to use them at high concentrations, their non-specific action or their toxic, irritant or allergenic properties. Thus, effective and harmless depigmenting substances for treating or preventing topical hyperpigmentation are particularly sought after in cosmetology and dermatology. In recent years, new approaches to treat diseases caused by melanocyte dysfunction have emerged. The use of antisense oligonucleotides has been considered in particular. Indeed, WO 99/25819 discloses oligonucleotides used to increase pigmentation by regulating the expression of tenascin to treat vitiligo and other depigmenting diseases and FR 2 804 960 discloses antisense oligonucleotides for regulating the expression of expression of tyrosinase or Tyrp-1 to treat hyperpigmentations.

Summary of the invention

The object of the present invention is to provide novel non-toxic, non-irritating, non-allergenic depigmenting agents having specific action on melanogenesis and stable in formulations suitable for topical administration.

The present invention relates, first of all, to a pharmaceutical or cosmetic composition comprising at least one kinesin inhibitor interacting with the AP-I adapter complex, in particular Kif13A, an inhibitor of a subunit of the AP-1 adapter complex. I, or an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting therewith. In a first preferred embodiment of the invention, said inhibitor is an inhibitor of kinesin Kif13A. In a second preferred embodiment of the invention, said inhibitor is an inhibitor of a subunit of the AP-I adapter complex. In a third preferred embodiment of the invention, said inhibitor is an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting with it, in particular kinesin Kif13A. . In particular, said inhibitor is a small molecule, an aptamer, an antibody, a nucleic acid or a dominant negative peptide. Preferably, said inhibitor is an aptamer, an antibody, a nucleic acid or a dominant negative peptide.

In a preferred embodiment, the present invention relates to a pharmaceutical or cosmetic composition comprising at least one nucleic acid comprising or consisting of a sequence capable of specifically hybridizing with a gene or mRNA encoding a subunit of the AP-I adapter complex. or for a kinesin interacting with the AP-I adapter complex, in particular Kif13A, and decreasing or suppressing the expression of this protein. In a first preferred embodiment of the invention, said at least one nucleic acid comprises or consists of a sequence capable of hybridizing specifically with a gene or mRNA encoding a kinesin interacting with the AP-I adapter complex, in particular Kif13A. , and decrease or suppress the expression of this protein. In a second preferred embodiment of the invention, said at least one nucleic acid comprises or consists of a sequence capable of hybridizing specifically with a gene or mRNA coding for a subunit of the AP-I adapter complex and of decreasing or to suppress the expression of this protein. Preferably, said nucleic acid is an antisense oligonucleotide or RNAi, preferably siRNA. Said nucleic acid may have a sequence of 15 to 50 nucleotides, preferably 15 to 30 nucleotides. In a preferred embodiment, said nucleic acid comprises a sequence selected from SEQ ID Nos. 1 to 6 and 11 to 24.

The composition may further comprise one or more other active substances, preferably selected from the group consisting of ellagic acid; arbutin; resorcinol; vitamin C; pantothenate; kojic acid; placental extracts; molecules interfering directly or indirectly with melanotropin (MSH), its receptor or adrenocorticotropic hormone (ACTH); polyols such as glycerin, glycol or propylene glycol; vitamins ; keratolytic and / or desquamating agents such as salicylic acid; alpha-hydroxy acids such as lactic acid or malic acid; ascorbic acid; retinoic acid; retinaldehyde; retinol; palmitate, propionate or acetate; anti-glycation agents and / or antioxidants such as tocopherol, thiotaurine, hypotaurine, aminoguanidine, thiamine pyrophosphate, pyridoxamine, lysine, histidine, arginine, phenylalanine, pyridoxine, adenosine triphosphate; anti-inflammatory agents; soothing agents and mixtures thereof; chemical or physical sunscreens and deoxyribonucleic acids or ribonucleic, and derivatives thereof. Preferably, this composition is suitable for topical use.

In another aspect, the present invention relates to the use of a pharmaceutical or cosmetic composition according to the present invention for the preparation of a medicament for the treatment or prevention of a pigment disorder. Preferably, the pigmentary disorder is hyperpigmentation.

In another aspect, the present invention relates to the use of a pharmaceutical or cosmetic composition according to the present invention as a cosmetic agent. Preferably, the cosmetic agent is a depigmenting agent.

Brief description of the drawings

Figure IA shows the results obtained by Western-blot experiments on melanocyte cell lysates transfected with siRNA-control, si-AP-1 RNA

(μlA), siRNA-AP-3 (β3A) or siRNA-Kif13A. The primary antibody used is an anti-Kif13A.

Figure 1B presents the results of the immunoprecipitations with an anti-

Kif13A or with an anti-γ-adaptin antibody (AP-I) made from cell lysates of melanocytes. The primary antibody used for the revelation of the Western blot is an anti-

Kifl3A. Figure 1C presents the results obtained by Western-blot experiments on melanocyte protein extracts transfected with an siRNA-control or a siRNA.

Kifl3A. The expression levels of kinesin Kifl3A and of the μlA subunit of the AP-I complex are here quantitatively evaluated using the expression of β-tubulin as a reference. Figure 2 shows a diagram showing the percentage of melanin in melanocytes transfected with siRNA-control or siRNA-Kif13A. The amount of melanin in melanocytes transfected with siRNA-control is considered to be 100%. The amount of melanin was determined by measuring the optical density of the cell lysate at a wavelength of 492 nm. Figure 3 shows electron micrographs of melanocyte sections transfected with siRNA-control or siRNA-Kif13A.

Figure 4 shows the results obtained by Western-blot experiments on melanocyte protein extracts transfected with siRNA-control or siRNA-μlA. The expression of the μ1 and γ-adaptin subunits of the AP-I complex is here quantitatively evaluated using the level of expression of β-tubulin as a reference.

FIGS. 5A and 5B show diagrams showing the percentages of white cells, that is to say melanocytes not containing pigmented mature melanosome, among the melanocytes transfected with siRNA-control, siRNA-μlA or siRNA. γ-adaptin (FIG. 5A) or with the combination of a siRNA-γ-adaptin and a siRNA-μlA (FIG. 5B). These measurements were performed by direct counting by optical microscopy (phase contrast).

Figure 6 shows a diagram showing the percentage of melanin in melanocytes transfected with siRNA-control, siRNA-μlA or the combination of siRNA-γ-adaptin and siRNA-μlA. The amount of melanin in melanocytes transfected with siRNA-control is considered to be 100%. The amount of melanin was determined by measuring the optical density of the cell lysate at a wavelength of 492 nm. Figure 7 shows electron micrographs of melanocyte sections transfected with siRNA-control and siRNA-μlA. The Roman numerals in the photos correspond to the maturation stages of the melanosomes present in the cell.

Detailed Description of the Invention The inventors have surprisingly demonstrated that melanin pigment synthesis can be decreased by means of a subunit inhibitor of the AP-I adapter complex or an inhibitor of an kinesin interacting with AP-I, in particular by means of a nucleic acid blocking the expression of a subunit of the AP-I adapter complex or a kinesin interacting with AP-I in the melanocytes. They have indeed observed that such a nucleic acid was not only capable of disturbing the transport of the melanogenesis enzymes of the Golgi apparatus towards the pre-melanosomes, thus blocking the maturation of these organelles, but also of decreasing the expression of the enzymes of melanogenesis. The inventors have thus revealed that this type of nucleic acid makes it possible to reduce or inhibit the synthesis of melanin in melanocytes by acting on different stages of melanogenesis and therefore constitutes new particularly effective depigmentation agents.

The present invention relates, first of all, to a pharmaceutical or cosmetic composition comprising at least one kinesin inhibitor interacting with the AP-I adapter complex, in particular Kif13A, a subunit inhibitor of AP-I adapter complex, or an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interfering therewith.

The term "AP-I" as used herein refers to the AP-I adapter complex that is involved in the trans-Golgi network. It should not be confused with the transcription factor of the same name which consists of proteins encoded by genes members of jun and fos families. The AP-I adapter complex is composed of 4 subunits: γ, β1, σ1 and μ1, and activation of any one of these subunits is sufficient to destabilize the complex and render it inoperative (Braun, 2007).

In a first preferred embodiment of the invention, said inhibitor is an inhibitor of a kinesin interacting with AP-I, in particular kinesin Kif13A.

The present invention relates to any type of inhibitor of a kinesin interacting with AP-I, in particular Kif 13 A. The inhibitor may be any molecule capable of decreasing the activity or the expression of kinesin. The inhibitor may be, but is not limited to, a small molecule, aptamer, antibody, nucleic acid or dominant negative peptide.

The term "small molecule" refers to a molecule of less than 1,000 daltons, including organic or inorganic compounds. The small molecule inhibitors of kinesin include, but are not limited to, acepromazine, chlorfenethazine, chlorpromazine, N-methyl chlorpromazine, cyamemazine, fluphenazine, mepazine, methotrimeprazine, methoxypromazine, nor chlorpromazine, perazine , perphenazine, phenothiazine, prochlorperazine, promethazine, propiomazine, putaperazine, thiethylperazine, thiopropazate, thioridazine, trifluoperazine, triflupromazine and the inhibitory molecules described in patent applications and patents WO 01/98278 , WO 02/057244, WO 02/079169, WO 02/057244, WO 02/056880, WO 03/050122, WO 03/050064, WO 03/049679, WO 03/049678, WO 03/049527, WO 03/079973 , US 6,890,933, WO 2008/070739, WO 2006/060737, WO 2006/119146 and US 6,777,200.

According to one embodiment, the inhibitor is an aptamer, an antibody, a nucleic acid or a dominant negative peptide. As used herein, the term "dominant negative peptide" refers to a peptide comprising at least a portion of a kinesin interacting with AP-I and capable of suppressing or decreasing its activity. Preferably, the dominant negative peptide consists only of the part of the kinesin interacting with AP-I, that is to say the part corresponding to the tail of kinesin. This peptide is therefore capable of interacting with the AP-I complex but, in the absence of the corresponding to the head of kinesin, is unable to move along the microtubules and thus to fulfill its function.

Several dominant peptides negative for kinesin Kif13A have already been described. In particular, a dominant negative peptide of Kif13A was obtained by expressing only the portion of the Kif13A protein corresponding to the tail of kinesin (Nakagawa et al., 2000).

In a preferred embodiment of the invention, the kinesin inhibitor is a nucleic acid comprising or consisting of a sequence capable of specifically hybridizing with a gene or mRNA encoding kinesin interacting with AP-I, in particular Kifl3A, and decrease or suppress the expression of this protein. Such nucleic acids are more fully detailed below.

In a second preferred embodiment of the invention, said inhibitor is an inhibitor of a subunit of the AP-I adapter complex. The present invention relates to any type of inhibitor of one of the subunits of the AP-I adapter complex. By inhibitor of one of the AP-I adapter complex subunits is meant any molecule capable of decreasing the activity or expression of one of the AP-I adapter complex subunits. The inhibitor may be, but is not limited to, a small molecule, aptamer, antibody, nucleic acid or dominant negative peptide. Preferably, the inhibitor is an aptamer, an antibody, a nucleic acid or a dominant negative peptide. In particular, the inhibitors of the γ and μl subunits are preferred.

The term "small molecule" refers to a molecule of less than 1,000 daltons, including organic or inorganic compounds.

Several dominant peptides negative for a subunit of the AP-I adapter complex have already been described. Notably, a negative dominant mutant of the μ1 subunit has been obtained by introducing a mutation into the tyrosine binding pocket and is described in Wonderlich et al (2008, J. Biol Chem, Vol 283, 3011-3022). .

The inhibitor may be an antibody specific for one of the AP-I subunits. Several of these antibodies are commercially available, for example antibodies specific for the γ subunit or the β1 subunit (Sigma-Aldrich). By inhibitor, it is also understood in the present application any molecule capable of reducing or preventing the attachment of a subunit of the AP-I adapter complex to the other subunits of the complex, that is to say any molecule capable of diminishing or preventing the formation of the AP-I complex. For example, the inhibitory molecule may be able to bind to one of the AP-I subunits and cause a a conformational change preventing the attachment of said subunit to one or more of the other AP-I subunits and thereby blocking the formation of the AP-I complex. It can also hide areas of interaction between subunits.

In a preferred embodiment of the invention, the AP-I adapter complex inhibitor is a nucleic acid comprising or consisting of a sequence capable of specifically hybridizing with a gene or mRNA encoding a complex subunit. AP-I adapter and decrease or suppress the expression of this protein. Such nucleic acids are more fully detailed below.

In a third preferred embodiment of the invention, said inhibitor is an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting with it, in particular kinesin Kif13A. . The present invention relates to any type of inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting therewith. Preferably, kinesin is Kif 13 A. Preferably, the subunit of AP-I is the β1 subunit. The kinesin Kif 13A tail interacts with the β1 subunit of the AP-I complex (Nakagawa et al., 2000). The inhibitor may be any molecule capable of diminishing or suppressing the interaction between kinesin and the AP-I complex. The inhibitor may be, but is not limited to, a small molecule, aptamer or antibody. Preferably, the inhibitor is an antibody directed against the domain of the β1 subunit interacting with Kif13A or against the tail domain of kinesin Kif13A interacting with the β1 subunit. The antibody binds to one or the other molecule and thus blocks the interaction between Kif13A and the AP-I complex. In addition, the inhibitor could also be a lure reproducing the domain of the β1 subunit interacting with Kif13A or the tail domain of Kifl3A interacting with the β1 subunit, this lure competing with Kifl3A or AP. -I for the interaction between these two elements.

The term "antibody" as used in the present invention includes monoclonal antibodies, chimeric antibodies, humanized antibodies, recombinant antibodies and fragments of said antibodies. By antibody fragment is meant, for example, the F (ab) 2, Fab, Fab 'or sFv fragments. According to a particular embodiment, the antibody may be IgG, IgM, IgA, IgD or IgE, preferably IgG or IgM. Antibody production methods are well known to those skilled in the art.

The term "aptamer" as used herein refers to a nucleic acid molecule or a peptide capable of specifically binding to a subunit of the AP-I complex or to a kinesin interacting with AP-I, in particular Kif13A. . Preferably, the aptamers are nucleic acids, preferably RNAs, generally comprising between 5 and 120 nucleotides (Osborne et al., 1997). They can be selected in vitro according to a process known as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). In the present description, the terms "nucleic acid", "nucleic sequence",

"Polynucleotide", "oligonucleotide", "nucleotide sequence" are used interchangeably and refer to a sequence of deoxyribonucleotides and / or ribonucleotides.

The term "RNAi" or "interfering RNA" as used herein refers to any single or double stranded RNA that interferes with a specific messenger RNA thereby leading to its degradation and decrease in its translation into protein. This term encompasses small interfering RNAs (siRNAs), double-stranded RNAs (dsRNAs), single-stranded RNAs (ssRNAs), short hairpin RNAs (ssRNAs), DNA-directed RNAi (ddARNi) and microRNAs (miRNAs). ). The term "hybridizing" herein means that Watson-Crick hydrogen bonds can be established between the complementary bases of two nucleic acid strands to form a duplex. The term "specifically hybridizable" means herein that the nucleic acid used according to the invention is capable of hybridizing to a gene or transcript encoding an AP-I subunit or a kinesin interacting with AP-I under high stringency hybridization conditions. Conditions of high stringency are widely described in the literature, for example in Sambrook et al., (1989), Maniatis et al., (1982 or one of his recent reissues) and in Ausubel et al, (1995), and these conditions can be adapted by those skilled in the art depending on the size of the nucleotide fragments, according to the appropriate teachings known. As an illustration, conditions of high stringency are advantageously as follows. Hybridization between the two strands (in particular DNA-DNA, RNA-RNA or DNA-RNA) is carried out in two stages: (a) prehybridization at 42 ° C. for 3 hours in phosphate buffer (20 mM, pH 7.5) containing 5 x SSC (1 x SSC corresponds to a solution 0.15 M NaCl / 0.015 M sodium citrate), 50% formamide, 7% sodium dodecyl sulfate (SDS), 1O x Denhardt's solution, 5% dextran sulfate and 1% salmon sperm DNA; (b) hybridization proper for 20 hours at a temperature dependent on the size of the probe (for example, 42 ° C for a probe of size greater than 100 nucleotides) followed by two 20-minute washes at 20 ^° C. with a solution 2 x SSC / 2% SDS, a 20 minute wash at 20 ^° C. with a 0.1 × SSC / solution 0.1% SDS. The last washing is carried out with a 0.1 × SSC / 0.1% SDS solution for 30 minutes at 60 ^° C. for a probe of size greater than 100 nucleotides.

In the context of the present invention, the term "gene coding for a subunit of AP-I or for a kinesin interacting with AP-I" is used to designate the genomic sequence coding for one of the γ subunits, β1, σ1 and μl of AP-I or for a kinesin interacting with AP-I, in particular Kif13A. This term encompasses the 5 'non-coding region, the region containing the initiation codon, the coding region and the 3' non-coding region of the gene. The term "gene encoding a subunit of AP-I" is used to designate the genomic sequence encoding one of the subunits γ, β1, σ1 and μ1 of AP-I. This term encompasses the 5 'non-coding region, the region containing the initiation codon, the coding region and the 3' non-coding region of the gene. The term "gene encoding a kinesin interacting with AP-I" is used to designate the genomic sequence encoding a kinesin interacting with AP-I, in particular Kif13A. This term encompasses the 5 'non-coding region, the region containing the initiation codon, the coding region and the 3' non-coding region of the gene.

In the context of the present invention, the term "mRNA coding for a subunit of AP-I or for a kinesin interacting with AP-I" is used to designate the ribonucleotide sequence resulting from the transcription of the gene coding for the corresponding protein. . This term includes the 3 'and 5' untranslated regions (3'-UTR and 5'-UTR), the exons and possibly the unspliced introns. The term "mRNA encoding an AP-1 subunit" is used to designate the ribonucleotide sequence derived from the transcription of the gene encoding the corresponding protein. The term "mRNA encoding a kinesin interacting with AP-I" is used to designate the ribonucleotide sequence derived from the transcription of the gene coding for the corresponding protein. More particularly, the term "mRNA encoding kinesin Kif13A" is used to designate the ribonucleotide sequence derived from the transcription of the gene encoding kinesin Kif13A.

Genomic sequences and proteins can be identified by their number in the GenelD database (http://www.ncbi.nlm.nih.gov/Genbank/index.html). Thus the GenelD input numbers for the subunits γ, β1, σ1 and μ1 of AP-I are respectively GenelD 164, GenelD 162, GenelD 1174, GeneID8907 and the GenelD entry number for kinesin Kifl3A of the being Human is GeneID63971. The terms "melanin", "melanin" and "melanin pigments" are used interchangeably here. They encompass the different pigments that can be synthesized in melanosomes, including eumelanin or pheomelanin.

The term "pharmaceutical composition" refers in this document to a composition according to the invention comprising a pharmaceutically acceptable carrier and / or excipient.

The term "cosmetic composition" refers in this document to a composition according to the invention comprising a cosmetically acceptable carrier and / or excipient.

The term "depigmenting agent" refers in this specification to an active agent capable of inhibiting or decreasing melanin synthesis in melanocytes and thereby bleaching the skin.

The inhibitors used according to the invention are capable, when introduced into a melanocyte, of inducing a decrease or a suppression of the expression or the activity of one or more subunits of AP-1 or of kinesin interacting with AP-I, in particular Kif13A, or of inducing a decrease or suppression of the interaction of a subunit of the AP-I adapter complex or the AP-I complex with a kinesin interacting with that in particular kinesin Kif13A, resulting in a significant decrease in the synthesis of melanin pigments.

According to a preferred embodiment, the nucleic acids used according to the invention are capable, when introduced into a melanocyte, of inducing a decrease or a suppression of the expression of one or more AP-1 subunits. or a kinesin interacting with AP-I, in particular Kif13A, with a consequent significant decrease in the synthesis of melanin pigments. According to a particular embodiment, the nucleic acids used according to the invention are capable, when introduced into a melanocyte, of inducing a decrease or a suppression of the expression of one or more PA subunits. -1, resulting in a significant decrease in the synthesis of melanin pigments. According to another particular embodiment, the nucleic acids used according to the invention are capable, when introduced into a melanocyte, of inducing a decrease or a suppression of the expression of a kinesin interacting with AP-I, in particular Kif13A, resulting in a significant decrease in the synthesis of melanin pigments These nucleic acids can act at the transcriptional or translational level.

By "decrease" of expression is meant, for example, a decrease of 30, 50, 70, 80, 90 or 95% of the product of gene expression. The nucleic acids used according to the invention may be DNA, RNA or chimeric DNA / RNA molecules. They may be in single-stranded or duplex form or a mixture of both. They may optionally comprise at least one modified or non-natural nucleotide such as, for example, a nucleotide comprising a modified base, such as inosine, methyl-5-deoxycytidine, dimethylamino-5-deoxyuridine, deoxyuridine or diamino. -2,6-purine, bromo-5-deoxyuridine or any other modified base for hybridization. The nucleic acids used according to the invention may also be modified at the level of the internucleotide linkage, for example phosphorothioates, H-phosphonates or alkylphosphonates, or at the level of the backbone such as, for example, alpha-oligonucleotides, the 2 ' -O-alkyl ribose or PNA (Peptid Nucleic Acid) (M. Egholm et al, 1992). These nucleic acids can be prepared by any method known to those skilled in the art such as, for example, chemical synthesis, library screening, in vivo transcription or recombinant DNA or amplification techniques. In a particular embodiment of the invention, the nucleic acid may be a

DNA that, when introduced into a cell induces the production of an interfering RNA (ddRNAi) allowing the inhibition of the expression of a target gene in the cell. This technology is known to those skilled in the art as DNA-directed RNA interference. In another preferred embodiment, the nucleic acid is RNA, preferably interfering RNA (RNAi). These RNAs can be natural, synthetic RNA or produced by recombinant techniques. They may also contain modified nucleotides or chemical modifications allowing them, for example, to increase their resistance to nucleases and thus to increase their lifespan in the cell. RNA interference is a phenomenon well known to those skilled in the art which makes it possible to specifically inhibit the expression of the target gene at the post-transcriptional level. Numerous patents and patent applications have described the use of RNAi molecules to inhibit gene expression, for example, in WO 99/32619, US 20040053876, US 20040102408 and WO 2004/007718. Preferably, the RNAi molecule is a siRNA molecule in double-stranded form of about 15 to 50 nucleotides in length, preferably about 15 to 30 nucleotides.

In an alternative embodiment of the present invention, the nucleic acid used to decrease or suppress AP-1 subunit or AP-I interacting kinesin expression, in particular Kif113A, is an antisense nucleic acid. Of in particular, the nucleic acid used to decrease or suppress the expression of an AP-1 subunit is an antisense nucleic acid. In another particular manner, the nucleic acid used to decrease or suppress the expression of a kinesin interacting with AP-I, in particular Kif13A, is an antisense nucleic acid. This antisense nucleic acid may be complementary to all or part of a sense nucleic acid encoding an AP-1 subunit or a keasin interacting with AP-I. In particular, the antisense nucleic acid may be complementary to all or part of a sense nucleic acid encoding an AP-1 subunit. In another particular manner, the antisense nucleic acid may be complementary to all or part of a sense nucleic acid encoding a kinesin interacting with AP-I. It may, for example, be complementary to an mRNA. The antisense nucleic acid generally comprises a nucleotide sequence complementary to at least a portion of the transcript of an AP-1 subunit or an AP-I interacting kinesin, and selectively hybridizes to these nucleic acid sequences. transcribed by conventional Watson-Crick interactions. In particular, the antisense nucleic acid generally comprises a nucleotide sequence complementary to at least a portion of the transcript of an AP-1 subunit. In another particular manner, the antisense nucleic acid generally comprises a nucleotide sequence complementary to at least a portion of the transcript of a kinesin interacting with AP-I. The antisense-inhibiting nucleic acid (s) can therefore bind to the transcripts of a gene coding for the γ, β1, σ1 and μ1 subunits of AP-I or coding for a kinesin interacting with AP-I and, for example , block access to the translation machinery at the 5 'end of the transcript of interest when the latter is an mRNA, interfere with its translation into protein, and allow the deletion of the expression of the transcript of interest in vivo (Kumar et al, 1993). In particular, the antisense-inhibiting nucleic acid (s) can bind to the transcripts of a gene coding for the subunits γ, β1, σ1 and μ1 of AP-I. In another particular manner, the antisense-inhibiting nucleic acid (s) can bind to transcripts of a gene encoding a kinesin interacting with AP-I, in particular Kif113A. Such polynucleotides have, for example, been described in patent EP 0 092 574. Preferably, the antisense nucleic acid is complementary to an mRNA coding for an AP-I subunit or for a kinesin interacting with AP-I. especially Kifl 13A. In particular, the antisense nucleic acid is complementary to an mRNA encoding an AP-1 subunit. In another particular manner, the antisense nucleic acid is complementary to an mRNA encoding a kinesin interacting with AP-I, in particular Kifl 13A. When the inhibitory nucleic acid is of the antisense type, it may cover all or part of the coding sequence of the transcript of interest, or all or part of the 3 'or 5' non-coding sequence. Preferably, the antisense inhibitory nucleic acid is complementary to the ribosome binding sequence and translation initiation. The inhibitory nucleic acid generally has a length of at least 10 ribonucleotides, for example, 10, 15, 20, 25, 30, 35, 40, 45 or 50 ribonucleotides in length, preferably 15 to 30 ribonucleotides in length.

An antisense nucleic acid used according to the invention can be synthesized by chemical synthesis methods or by recombinant DNA techniques known to those skilled in the art. The DNA or antisense RNA can in particular be synthesized chemically, produced by in vitro transcription of linear matrices (for example, by PCR) or circular matrices (for example, from viral vectors or not), or produced by transcription in vivo from viral vectors or not. The antisense nucleic acids can be modified to increase their stability, their resistance to nucleases, their specificity or their pharmacological properties. For example, an antisense nucleic acid may have modified nucleotides used to increase the stability of the duplexes formed between sense and antisense nucleic acids.

According to another embodiment, the inhibitory nucleic acid is of the ribozyme type. Ribozymes are catalytic RNA molecules that possess a ribonuclease activity and are thus capable of cleaving single-stranded nucleic acids, such as mRNAs of which they are complementary. Transcription specific ribozymes encoding an AP-I subunit or an AP-I interacting kinesin can be designed, synthesized and produced according to methods well known to those skilled in the art (see, for example, Fanning and Symonds, 2006). The ribozyme generally has two distinct regions. A first region that has a certain specificity for the transcript of interest, that of a gene encoding an AP-I subunit or a kinesin interacting with AP-I, and is therefore able to bind to it , while the second region confers on the ribozyme its catalytic activity of cleavage, ligation and splicing of the transcript of interest. In particular, the first region has a certain specificity for the transcript of interest, that of a gene encoding an AP-1 subunit. In another particular manner, the first region has a certain specificity for the transcript of interest, that of a gene encoding a kinesin interacting with AP-1, in particular Kif113A. Various types of ribozymes can be used as per examples are hammerhead ribozymes or circular ribozymes, hairpin ribozymes or lasso ribozymes.

The interfering RNA or antisense nucleic acids used according to the invention can be administered in the form of precursors or DNA molecules coding for them.

The nucleic acid used according to the invention is generally from 15 to 50 nucleotides in length, preferably from 15 to 30 nucleotides in length.

In the present invention, the nucleic acid is capable of hybridizing specifically to a gene or transcript encoding a subunit of the AP-I complex or for a kinesin interacting with AP-I, in particular Kif113A. According to one embodiment, the nucleic acid is capable of hybridizing specifically to a gene or transcript encoding a subunit of the AP-I complex. According to another embodiment, the nucleic acid is capable of hybridizing specifically to a gene or transcript coding for a kinesin interacting with AP-I, in particular Kif113A. It is nevertheless understood that the nucleic acid according to the invention does not need to have a complementarity of 100% with the target sequence to hybridize specifically. In particular, a nucleic acid having a degree of complementarity of at least about 90% is able to hybridize specifically. Preferably, the degree of complementarity between the nucleic acid of the invention and the target sequence is 95, 96, 97, 98, 99 or 100%.

In a preferred embodiment, the nucleic acid used according to the invention comprises or consists of one or more sequences capable of specifically hybridizing with a gene or mRNA coding for a subunit of the AP-I adapter complex or for kinesin Kifl3A. Preferably, the nucleic acid comprises or consists of one or more sequences chosen from the sequences SEQ ID No. 1 to 6 and 11 to 24. In a particular embodiment, the nucleic acid used according to the invention comprises or consists of in one or more sequences capable of specifically hybridizing with a gene or mRNA encoding a subunit of the AP-I adapter complex. Preferably, the nucleic acid comprises or consists of one or more sequences selected from SEQ ID No. 5, 6 and 11 to 24. Most preferably, the nucleic acid comprises or consists of one or more sequences capable of to hybridize specifically with a gene or mRNA coding for the AP-I λ-β-adaptin subunit. In another particular embodiment, the nucleic acid used according to the invention comprises or consists of one or more sequences capable of hybridizing specifically with a gene or mRNA encoding kinesin Kif13A. Preferably, the nucleic acid comprises or consists of one or more sequences chosen from the sequences SEQ ID No. 1 to 4.

In a most particularly preferred embodiment, the nucleic acid used according to the invention comprises or consists of a double-stranded interfering RNA molecule formed by one of the following pairs: SEQ ID Nos. 1 and 2, SEQ ID Nos. 3 and 4, SEQ ID Nos. 5 and 6, SEQ ID Nos. 11 and 12, SEQ ID Nos. 13 and 14, SEQ ID Nos. 15 and 16, SEQ ID Nos. 17 and 18, SEQ ID Nos. 19 and 20, SEQ ID Nos. 21 and 22 and SEQ ID Nos. 23 and 24. In a particular embodiment, the nucleic acid used according to the invention comprises or consists of a double-stranded interfering RNA molecule formed by one of the following pairs: SEQ ID Nos. 1 and 2 and SEQ ID Nos. 3 and 4. In another particular embodiment, the nucleic acid used according to the invention comprises or consists of a double-stranded interfering RNA molecule formed by one of the following pairs: SEQ ID Nos. 5 and 6, SEQ ID Nos. 11 and 12, SEQ ID Nos. 13 and 14, SEQ ID Nos. 15 and 16, SEQ ID Nos. 17 and 18, SEQ ID Nos. 19 and 20, SEQ ID Nos. 21 and 22 and SEQ ID Nos. 23 and 24.

The present invention relates to a pharmaceutical or cosmetic composition comprising at least one inhibitor of a subunit of the AP-I adapter complex, an inhibitor of a kinesin interacting with the AP-I adapter complex, in particular Kifl 13A, or an inhibitor the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting therewith, in particular any inhibitor as defined in the present application.

According to a preferred embodiment, the present invention relates to a pharmaceutical or cosmetic composition comprising at least one nucleic acid comprising or consisting of a sequence capable of specifically hybridizing with a gene or mRNA coding for a subunit of the AP-I adapter complex. or for a kinesin interacting with the AP-I adapter complex, in particular Kif113A, and decreasing or suppressing the expression of this protein, as described in the present application. In a particular embodiment, the pharmaceutical or cosmetic composition comprises at least one nucleic acid comprising or consisting of a sequence capable of hybridizing specifically with a gene or an mRNA encoding a subunit of the AP-I adapter complex and of reduce or eliminate the expression of this protein, as described in the present application. In another particular embodiment, the pharmaceutical or cosmetic composition comprises at least one nucleic acid comprising or consisting of a sequence capable of hybridizing specifically with a gene or mRNA encoding a kinesin interacting with the AP adapter complex

1 and to decrease or eliminate the expression of this protein, as described in the present application. Preferably, kinesin is kinesin Kif13A.

Preferably, the composition is a pharmaceutical or cosmetic composition whose formulation is suitable for topical administration. The inhibitor used in the composition is present in an effective amount. Depending on the type of inhibitor used, an effective amount is an amount to achieve a decrease or suppression of the expression or activity of a subunit of the AP-I adapter complex or a interacting kinesin with the AP-I adapter complex, in particular Kif13A, or a decrease or suppression of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting therewith.

According to the preferred embodiment where the inhibitor is a nucleic acid, the nucleic acid used in the composition is present in an effective amount, for example, ranging from 0.00001% to 10% and preferably from 0.0003% to 3%. % (w / w) of the total weight of the composition. The term "effective amount" as used in the present application is an amount of inhibitor used according to the invention to achieve a significant decrease in melanin synthesis. According to a preferred embodiment, the term "effective amount" as used in the present application is an amount of nucleic acid used according to the invention to obtain a significant decrease in melanin synthesis. This decrease may, in particular, result in a visible change in the color of the skin. This decrease may, for example, be 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50% of the amount of melanin present in untreated cells. It can be measured by one of the methods described in the examples or known to those skilled in the art. The composition according to the invention may comprise several inhibitors whose type and target may be identical or different. It may comprise inhibitors of either a subunit of the AP-I adapter complex, or of a kinesin interacting with the AP-I adapter complex, in particular Kif133A, or of the interaction between a subunit of the complex AP-I adapter or the AP-I complex and a kinesin interacting therewith. It may comprise inhibitors of a similar nature (for example only nucleic acids) or different (for example aptamers, antibodies and / or nucleic acids). According to a preferred embodiment, this composition may comprise several nucleic acids comprising a sequence capable of hybridizing specifically with a gene or an mRNA coding for a subunit of the AP-I adapter complex or for a kinesin interacting with the AP-I adapter complex, in particular KifI 13A, and decreasing or suppressing the expression of this protein, as described in the present application. It may also comprise a combination of several nucleic acid inhibitors targeting either the same subunit of AP-1, or different AP-1 subunits, or the same kinesin interacting with AP-1, or different interacting kinesins. with AP-I. In a particular embodiment, the composition may comprise a plurality of nucleic acids comprising a sequence capable of specifically hybridizing with a gene or mRNA encoding a subunit of the AP-I adapter complex and of decreasing or eliminating the expression protein, as described in the present application. It may also comprise a combination of several inhibitory nucleic acids targeting either the same AP-1 subunit or different AP-1 subunits. In another particular embodiment, the composition may comprise a plurality of nucleic acids comprising a sequence capable of hybridizing specifically with a gene or mRNA encoding a kinesin interacting with the AP-I adapter complex, in particular KifI 13A, and of reduce or eliminate the expression of this protein, as described in the present application. It may also comprise a combination of several nucleic acid inhibitors targeting either the same kinesin interacting with AP-I, or different kinesins interacting with AP-I.

The composition according to the invention may also comprise one or more additional active substances intended to enhance the desired effects, for example ellagic acid; arbutin; resorcinol; vitamin C; pantothenate; kojic acid; placental extracts; molecules interfering directly or indirectly with melanotropin (MSH), its receptor or adrenocorticotropic hormone (ACTH); polyols such as glycerin, glycol or propylene glycol; vitamins ; keratolytic and / or desquamating agents such as salicylic acid; alpha-hydroxy acids such as lactic acid or malic acid; ascorbic acid; retinoic acid; retinaldehyde; retinol; palmitate, propionate or acetate; anti-glycation agents and / or antioxidants such as tocopherol, thiotaurine, hypotaurine, aminoguanidine, thiamine pyrophosphate, pyridoxamine, lysine, histidine, arginine, phenylalanine, pyridoxine, adenosine triphosphate; anti-inflammatory agents; soothing agents and mixtures thereof; chemical or physical sunscreens and deoxyribonucleic or ribonucleic acids, and derivatives thereof. The composition according to the invention may be in any galenical form normally used for topical application, especially in the form of an aqueous, aqueous-alcoholic or oily solution, an oil-in-water or water-in-oil or multiple emulsion, a gel aqueous or oily, a liquid anhydrous product, pasty or solid, an oil dispersion in a polymeric phase such as nanospheres and nanocapsules or better lipid vesicles of ionic and / or nonionic type as described in French patent FR 2534487.

In particular, the composition according to the invention may comprise at least one inhibitor, preferably an inhibitory nucleic acid, described in the present application, encapsulated in a liposome.

The term "liposome" is intended to denote, according to the present invention, small artificially manufactured vesicles consisting of lamellae of phospholipids separated from each other by aqueous compartments. They have a structure very close to that of cell membranes, which allows them to merge with them by releasing the active ingredient (s) they contain. The liposomes that may be used according to the invention may be multilamellar liposomes or MLVs (MultiLamellar Vesicle), small unilamellar liposomes or SUVs (Small Unilamellar Vesicle), or large unilamellar liposomes or LUVs (Large Unilamellar Vesicle). The liposome may also be a nonionic liposome whose wall is no longer composed of phospholipids but nonionic lipids. The composition according to the invention may be more or less fluid and have the appearance of a white or colored cream, an ointment, a milk, a lotion, a serum, a paste or of a foam. It can optionally be applied to the skin in the form of an aerosol. It may also be in pulverulent solid form or not, for example in stick form. It can still be in the form of patches, pencils, brushes and applicators allowing a localized application on the spots of the face or hands. It can be used as a care product and / or as a makeup product.

In a known manner, the composition according to the invention may also contain the usual adjuvants in the cosmetic and dermatological fields, such as hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents, preservatives, antioxidants, solvents, perfumes, fillers, filters, pigments, odor absorbers and dyestuffs. The amounts of these various adjuvants are those conventionally used in the fields under consideration. These adjuvants, according to their nature, may be introduced into the fatty phase, into the aqueous phase, into the lipid vesicles and / or into the nanoparticles.

When the cosmetic or dermatological composition of the invention is an emulsion, the proportion of the fatty phase can range from 5 to 80% by weight, and preferably from 5 to 50% by weight relative to the total weight of the composition. The oils, emulsifiers and co-emulsifiers used in the composition in emulsion form are chosen from those conventionally used in the field under consideration. The emulsifier and the co-emulsifier are present in the composition in a proportion ranging from 0.3% to 30% by weight, and preferably from 0.5% to 20% by weight relative to the total weight of the composition. composition.

As oils which can be used in combination with the inhibitors according to the invention, in particular with the nucleic acids according to the invention, mention may be made of mineral oils such as liquid petrolatum; vegetable oils such as avocado oil or soybean oil; oils of animal origin such as lanolin; synthetic oils such as perhydrosqualene; silicone oils such as cyclomethicone and fluorinated oils such as perfluoropolyethers. It is also possible to use fatty alcohols such as cetyl alcohol, fatty acids or waxes such as carnauba wax or ozokerite as fat.

Examples of emulsifiers and coemulsifiers that may be used in combination with the nucleic acids according to the invention include, for example, fatty acid and polyethylene glycol esters such as PEG-20 stearate and fatty acid and glycerol esters such as than glyceryl stearate.

As hydrophilic gelling agents that can be used in combination with the inhibitors, in particular the nucleic acids, according to the invention, it is possible to use, for example, carboxyvinyl polymers (carbomer), acrylic copolymers such as copolymers of acrylates / alkylacrylates, polyacrylamides , polysaccharides, natural gums and clays. As lipophilic gelling agents, it is possible to use, for example, modified clays such as bentones, metal salts of fatty acids, hydrophobic silica or polyethylenes. The present invention also relates to the use of a composition according to the invention as a cosmetic agent. According to a preferred embodiment, the cosmetic agent is a depigmenting agent.

The present invention relates to a pharmaceutical or cosmetic composition comprising at least one inhibitor of a subunit of the AP-I adapter complex, a inhibitor of a kinesin interacting with the AP-I adapter complex, in particular

Kif113A, or an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and a kinesin interacting therewith, for use in the treatment of pigment disorders. In a particular embodiment, the inhibitor may be, but is not limited to, a small molecule, an aptamer, an antibody, a nucleic acid or a dominant negative peptide.

According to a preferred embodiment, the present invention relates to a pharmaceutical composition comprising at least one nucleic acid comprising a sequence capable of hybridizing specifically with a gene or an mRNA coding for a subunit of the AP-I adapter complex or for a interacting kinesin. with the AP-I adapter complex, in particular Kif13A, and to decrease or suppress the expression of this protein, for the treatment of pigment disorders. In particular, the present invention relates to a pharmaceutical composition comprising at least one nucleic acid comprising a sequence capable of specifically hybridizing with a gene or mRNA encoding a subunit of the AP-I adapter complex and reducing or eliminating the expression of this protein, for the treatment of pigment disorders. In another particular manner, the present invention relates to a pharmaceutical composition comprising at least one nucleic acid comprising a sequence capable of hybridizing specifically with a gene or mRNA encoding a kinesin interacting with the AP-I adapter complex, in particular Kifl 13 A, and decrease or suppress the expression of this protein, for the treatment of pigment disorders.

The present invention also relates to the use of a pharmaceutical composition according to the invention, for the preparation of a medicament for the treatment or prevention of a pigment disorder. The present invention also relates to a cosmetic or pharmaceutical method for depigmenting and / or bleaching human skin or treating or preventing a pigmentary disorder consisting in applying to the skin depigmenting a cosmetic or pharmaceutical composition according to the invention .

The pigmentary disorders to be treated may be hyperpigmentations or hypopigmentations. In the case of local hyperpigmentations, these can result from certain melanocytic disorders and are characterized by an accumulation of melanin. The pigmentary disorder to be treated may be hyperpigmentation such as, for example, idiopathic melasma (not associated with pregnancy or taking oral contraceptives), melasma (also called chloasma or pregnancy mask), actinic lentigo (also called senile lentigo, senile stain, age task or solar lentigo), acne pigmentary sequelae, post-inflammatory pigmentations due to abrasion, burn, scarring, dermatitis and / or contact allergy, pigmentations due to the dermatitis of the meadows, pigmentations due to poison ivy (also called Poison Ivy plant), ephelids (also called freckles), nevi such as congenital giant nevi, Becker's nevus or Spitz's nevus. Hyperpigmentations may be hyperpigmentations with genetic determinism or hyperpigmentations of metabolic or medicinal origin. They may be of accidental origin and caused for example by photosensitization or post-injury healing. The pigment disorder can also result in hypopigmentation, such as vitiligo. In a preferred embodiment, the pigment disorder to be treated is hyperpigmentation. Preferably, the hyperpigmentation is a melasma, an idiopathic melasma or an actinic lentigo.

In the case of hyperpigmentation, the treatment aims to depigment the hyperpigmented areas and thus reduce or eliminate the visible symptoms associated with these specific pigment disorders.

In the case of hypopigmentation, the purpose of the treatment may be to standardize the color of the skin by depigmenting the residual pigmented areas.

In the case of hyperpigmentation, the aim of prevention is to prevent the appearance of hyperpigmented areas and, in the case of hypopigmentation, to avoid the appearance of skin color disparities.

The following examples are presented for illustrative and non-limiting purposes.

Examples Materials and Methods

Cells, Antibodies and Reagents

The human melanocyte line MNT-I is maintained in culture as previously described (Raposo et al., 2001).

The antibodies used in this example are listed below:

- A polyclonal antibody anti rabbit β-tubulin (ab6046, Abcam ^®);

- Anti-μlA rabbit polyclonal antibody (AP-I subunit) (Dr. Linton Traub, University of Pittsburgh);

- Monoclonal anti-γ-adaptin mouse (clone 100/3; SIGMA ^®); Anti-Tyrpl mouse monoclonal antibody (tyrosinase related protein-1) derived from culture supernatant TA99 (Mel-5) (American Type Culture Collection, Manassas, VA);

- anti-tyrosinase polyclonal antibody (abl5175, Abcam ^®);

- antibodies monoclonal anti-Pmel 17 (HMB50, Labvision ^®); Anti-Kif13A rabbit polyclonal antibody (Bethyl Laboratories, Montgomery, US);

- Rabbit polyclonal antibody and mouse monoclonal anti-horseradish peroxidase (HRP) (Jackson Immunoreserach ^® ); and

- Anti-mouse rabbit antibodies coupled to Texas Red (Invitrogen ^®).

Reagents other than the antibodies used in this example are listed below:

- Protein-A coupled to colloidal gold particles (Cell Microscopy Center, University of Utrecht, the Netherlands);

- Protein G Agarose (Invitrogen ^® , catalog number 15920-010)

- Kit for western blot containing NuPAGE Bis-Tris 4-12% gels, NuPAGE 3-8% Tris- Acetate gels, MES-SDS Migration and Transfer Buffer (Invitrogen ^® );

- ECL kit "western blotting detection reagents" (Amersham ^® ) for the revelation of HRP activity on PVDF membranes (Millipore ^® );

- Paraformaldehyde (PFA) and bovine serum albumin (BSA) (Sigma ^® );

- Saponin (Carlo Erba Reagents ^® ); and - Mounting medium of "ProLong ^® GoId Antifade Reagent" fluorescence microscope slides with DAPI (Invitrogen ^® ).

Interfering RNA sequences

SEQ ID N ⁰ I siRNA Kifl3A sense GGCGGGUAGCGAAAGAGUA dTdT

SEQ ID NO: 2 siRNA Kifl3A antisense UACUCUUUCGCUACCCGCC dAdG

SEQ ID NO: 5 siRNA AP-I μL A sense GGCAUCAAGUAUCGGAAGA dTdT

SEQ ID No. 6 siRNA AP-I μlA antisense UCUUCCGAUACUUGAUGCC dTdT

SEQ ID NO: 7 siRNA AP-3 (β3A) sense GGCUGAUCUUGAAGGUUUA dTdT

SEQ ID NO: 8 siRNA AP-3 (β3A) antisense UAAACCUUCAAGAUCAGCC dTdT

SEQ ID NO: 9 siRNA control sense UUCUCCGAACGUGUCACGU dTdT SEQ ID N ⁰ IO siRNA control antisense ACGUGACACGUUCGGAGAA dTdT SEQ ID NO: 19 siRNA γ-adaptin sense ACCGAAUUAAGAAAGUGGU dTdT

SEQ ID NO: 20 siRNA γ-adaptin antisense ACCACUUUCUUAAUUCGGU dTdT

Interference by V ARN

Ixio ⁶ cells were seeded in a culture dish of 10 cm for two days, then washed twice with PBS preheated before being placed in culture in 4 ml of OptiMEM medium (Invitrogen ^®) in an oven for 40 min.

A solution was obtained by mixing 10 μl of 20 μM siRNA with 840 μl of OptiMem medium and incubating this mixture for 20 min at room temperature. A solution B was obtained by mixing 50 L of Oligofectamine ™ (Invitrogen ^®) with 150 .mu.l of OptiMEM medium and incubating this mixture for 20 min at room temperature.

Solutions A and B were then mixed and left for 20 min at room temperature.

Then, this mixture was deposited on the cells which were kept in an oven for 4 hours. 5 ml of complete medium containing 40% fetal calf serum (FCS) was then added to the cells. 24 hours later, the cells were recovered and seeded in 6-well plates with a concentration of 1.5x10 ⁵ cells / well. This same protocol was repeated the next day by adapting the volumes.

Western blot

Following interference by the RNA, the cells were washed twice with PBS, and then incubated with 200 μl of lysis buffer (50 Mm Tris, 150 mM NaCl, 10 Mm EDTA, 1% Triton, 1% protease inhibitor, pH 8) per well on ice for 15 min. The cells were then scraped, centrifuged (15,000 rpm, 4 ° C) and the supernatants were collected. The amount of total protein was measured by the "BCA Protein Assay" kit (Pierce ^® ). 10 μg of each supernatant was deposited on a gel and the migration took place for 35 min at 200 V. The gel was then transferred to a PVDF membrane (Millipore ^® ) for 1 hour at 30 V. Then, the membrane was saturated with PBS / 0.1% Tween / 5% BSA for 1 hour at room temperature, incubated for 45 min with the primary antibody diluted in WB buffer (PBS / 0.1% Tween), rinsed 3 times 10 min. with WB buffer, incubated for 45 min with the corresponding secondary antibody coupled to HRP diluted in WB buffer and rinsed 3 times 10 min in WB buffer. HRP activity was then revealed using the ECL kit "western blotting detection reagents" (Amersham ^® ). Fluorescence microscopy

The cells previously seeded on glass slides (0.5 × 10 ⁵ cells / coverslip) were washed twice with preheated PBS and then fixed for 10 minutes in a solution of PBS / 4% PFA. After two washes at room temperature with PBS, excess unreacted PFA was neutralized by treatment with 50 mM Glycine / PBS for 10 minutes. The nonspecific binding sites were then saturated by two washes of 3 minutes with PBS supplemented with 2 mg / ml of BSA and the cells were permeabilized with permeabilization buffer (PBS / 2% BSA / 0.05% saponin). ). The coverslips were then contacted with 25 μl of primary antibody diluted in permeabilization buffer for 45 minutes at room temperature and the excess of antibody was removed by two washes of 3 minutes with the permeabilization buffer. The coverslips were then incubated for 45 minutes at room temperature with 25 μl of secondary antibody diluted in permeabilization buffer. After two washes of 3 minutes with the permeabilization buffer followed by washing with PBS, the slides were mounted on microscope slides with 15 μL of mounting medium (ProLong ^® GoId Antifade Reagent with DAPI, Invitrogen ^® ) allowing to attenuate the loss of fluorescence during the observation.

immunoprecipitation

The melanocyte cells were cultured in flasks of 75 cm ² until confluent, then lysed in lysis buffer (50 mm Tris, 150 mM NaCl, 10 mm EDTA, 1% Triton, 1% protease inhibitor, pH 7 , 3) for 20 minutes at 4 ° C. The cells were then scraped and centrifuged (15000 rpm, 4 ° C) and the supernatants were collected. The beads coupled to the agarose G protein were washed in the lysis buffer and 20 μl of these beads were incubated with the lysates for 1 hour at 4 ° C. under rotation. The lysates were then centrifuged at 4000 rpm and the supernatants were collected and then incubated with washed beads which had been incubated for 1 h with 1 μg of rabbit antibody (Kifl3A control) or mouse anti-CD9 (γ control AP-1 adaptin). Immunoprecipitation is then carried out by centrifuging the lysates at 4000 rpm and bringing the supernatants into contact with 20 μl of washed beads previously incubated for 2 h at 4 ° C. under rotation with 1 μg of rabbit antibody (Kifl3a control). anti-Kifl3a antibody (Kifl3a), anti-CD9 mouse antibody (AP-1 γ-adaptin control) or mouse anti-γ-adaptin (γ-adaptin AP-1). The lysates were then centrifuged at 4000 rpm, the supernatants collected and gel-deposited for Western Blot analysis.

Electron microscopy

The melanocyte cells previously seeded in 6-well dishes and treated with "control" siRNAs and siRNA-Kifl3A or siRNA-μlA were fixed either with a mixture of 2% PFA and 2% glutaraldehyde (conventional microscopy) or a mixture 2% PFA and 0.5% glutaraldehyde (immunolabeling) in 0.2 M phosphate buffer pH 7.4 for 4 hours at room temperature.

Conventional Microscopy: After several washes in 0.2M sodium cacodylate buffer, cells were fixed with 2% osmic acid solution (OsO ₄ ) for 45 min. After rinsing with distilled water, the cells were dehydrated with increasing concentrations of ethanol and then coated in Epon 812 resin. After polymerization for 48 hours at 60 ^° C., ultrafine sections were made, contrasted with 4% uranyl acetate for 5 min and observed under an electron microscope (Phillips CM120, FEI Company ^® ). Imaging was performed with a KeenView camera (SIS ^® , Germany). Immunolabeling: After several washes in 0.2M phosphate buffer containing 0.1M glycine, the cells were prepared for ultracryomicrotomy as previously described in Raposo et al. (1997).

Briefly, the cell pellets were first coated in 10% gelatin. After solidification at 4 ° C., 1 mm ³ blocks were cut and infused in 2.3M sucrose for 2 hours. The cell blocks were frozen on their support and ultrafine frozen sections were made with an ultracryo micro volume (Leica ^® , Austria). Sections recovered on electron microscopy grids were immunostained with anti-Tyrpl and anti-Pmell7 antibodies. These antibodies were visualized with protein A coupled to colloidal gold particles. The sections were contrasted and embedded in a mixture of uranyl acetate and methylcellulose before observation under an electron microscope (Phillips CM120, FEI Company ^® ). Imaging was performed with a KeenView camera (SIS ^® , Germany). Quantification of melanin

After the interference with the RNA, the cells were washed twice in PBS and incubated with 150 μl of melanine buffer (50 mM Tris, 2 mM EDTA, 150 Mm NaCl, 1% protease inhibitor, pH 7 4). They were then scraped and grouped in a single fraction before being sonicated for 20 seconds at maximum intensity. 10 μL were then taken to quantify the proteins (with the BCA Protein Assay kit, Pierce) and 200 μg of proteins were removed and centrifuged at 15,000 rpm for 15 min at 4 ° C. The supernatant was removed and the pellet washed with 500 μl of an ethanol / ether solution (1: 1). Finally, the pellet was solubilized with 230 μl of a 2 M NaOH / 20% DMSO solution at 55 ° C. Once solubilized, 200 μL was taken to measure the optical density at 492 nm.

Quantification of white cells

Quantification was performed on cells prepared for immunofluorescence using an epifluorescence microscope. The cells were observed in phase contrast and the presence (black) or absence (white) of pigmented mature melanosomes was quantified.

Example 1

Western blot experiments on melanocyte cell lysates transfected with siRNA-AP-1 (μlA), siRNA-Kif13A and siRNA-AP-3 (β3A) demonstrated that the expression of Kifl3A did not occur. is not disturbed by the inactivation of AP-I or AP-3 (Figure IA). In contrast, in melanocytes transfected with siRNA-Kif13A, the expression of Kif13A was completely suppressed (FIGS. 1A and 1C) whereas the expression of the AP-1 μlA subunit was not suppressed. disrupted. These results thus show the efficiency and the specificity of siRNAs for the inactivation of this protein in melanocytes.

In addition, immunoprecipitation experiments carried out on melanocytes have made it possible to demonstrate that the Kif13A protein co-precipitates with the γ-adaptin subunit of AP-1 and therefore that the interaction between Kif13A and AP-I previously observed. in non-melanocytic cell lines (Nakagawa et al., 2000) also exists in melanocyte lines (Figure 1B).

The relative amount of melanin in melanocytes transfected with siRNA-Kif13A compared to the amount present in cells transfected with siRNA control was determined by measuring the optical density of the cell lysate at a wavelength of 492 nm (Figure 2). The results presented in Figure 2 show that the use of siRNA-Kifl3A made it possible to obtain a reduction in the amount of melanin synthesized of the order of 40% compared to the cells transfected with the siRNA-control.

Electron microcopy observations were performed on melanocytes transfected with siRNA-Kif13A or siRNA-control either by conventional electron microscopy (FIG. 3) or with immunolabeling with anti-Tyrpl antibodies (data not shown). .

Conventional electron microscopy experiments have demonstrated that melanocytes transfected with siRNA-control contained numerous melanosomes with large amounts of melanin (black in Figure 3). In contrast, melanocytes transfected with RNsi-Kifl3A contained little or no pigments.

In cells transfected with siRNA control, immunostaining revealed numerous mature stage III or IV melanosomes concentrating Tyrpl proteins. In contrast, cells transfected with siRNA-Kif13A, no mature melanosome was visible and the Tyrpl enzyme was dispersed in vesicular structures with endosome characteristics.

Thus, the inactivation of kinesin Kif13A disrupts the transfer of melanogenesis enzymes in pre-melanosomes and thus blocks the maturation of these organelles, which are therefore unable to ensure the synthesis of melanin.

Conclusion

The results obtained by these experiments made it possible first of all to observe that the use of specific siRNA makes it possible to inactivate kinesin Kif13A in melanocytes.

The results obtained also demonstrate that the use of a siRNA specific for kinesin Kif13A significantly reduces:

the quantity of melanin produced in the melanocytes,

the amount of melanocytes containing pigmented mature melanosomes and the proportion of mature melanosomes (stage III or IV) in the melanocytes.

By these experiments, the inventors have therefore demonstrated that the kIASI-specific siRNAs interacting with AP-I, and in particular Kinesin Kif13A, have a significant effect on the production of melanin pigments and can therefore be effectively used as depigmenting agents. . Example 2

Western blot experiments on transfected melanocytes (FIG. 4) made it possible to demonstrate that the expression of the μLA subunit of AP-I is greatly decreased in melanocytes transfected with siRNA-μlA in comparison with those transfected with siRNA-control. This decrease in expression also led to a decrease in the expression of another subunit of AP-I, the γ-adaptin, with the consequence of destabilizing the AP-I adapter complex. These results therefore confirm that the inactivation of a single subunit of AP-I is sufficient to completely destabilize this complex. It has, moreover, been surprisingly observed that in cells transfected with siRNA-μlA and thus deficient in AP-I, the expression of tyrosinase, the key enzyme of melanogenesis, has been greatly reduced, as well as the expression of the enzyme Tyrp-1 although less importantly.

These results thus demonstrate that the inactivation of a single subunit of AP-I is sufficient to destabilize and inactivate the adapter complex but also disrupts the expression of the main enzymes of melanogenesis.

Quantification of the white cells, i.e. cells not containing pigmented mature melanosome, among the transfected melanocytes, was performed by direct counting under optical microscopy (phase contrast) (FIGS. 5A and 5B) and the The percentage of melanin in these cells relative to the amount present in siRNA-control transfected cells was determined by measuring the optical density of the cell lysate at a wavelength of 492 nm (Figure 6). FIGS. 5A, 5B and 6 show the results obtained on the melanocytes transfected with a siRNA control, an siRNA-1μA, an siRNA-γ-adaptin or an siRNA-1μA and siRNA-γ-adaptin combination. The results presented in FIGS. 5A and 5B show that the use of siRNA-1μA, siRNA-γ-adaptin (FIG. 5A) or both simultaneously (FIG. 5B) made it possible to significantly increase the proportion of white cells among the transfected melanocytes, compared with those transfected with the siRNA-control. This increase reached even 24% for cells transfected with siRNA-lμA alone. These results were confirmed by those presented in FIG. 6 where it appears that transfection of siRNA-1μA, siRNA-γ-adaptin or both simultaneously made it possible to significantly reduce the amount of melanin synthesized in the cells by comparison. with those transfected with siRNA-control. This decrease could reach more than 40% in cells transfected with siRNA-lμA. These results therefore demonstrate that the inactivation of one or more subunits of the AP-I complex by one or more siRNAs makes it possible to significantly reduce melanin synthesis in the melanocytes.

Observations in electron microcopy were performed on melanocytes transfected with siRNA-μlA or siRNA-control either by conventional microscopy (FIG. 7) or with immunolabeling with anti-Tyrpl antibodies.

(data not shown).

Conventional electron microscopy experiments have demonstrated that melanocytes transfected with the siRNA-control contained numerous melanosomes with large amounts of melanin (black in Figure 7). In contrast, melanocytes transfected with siRNA-μlA contained little or no pigment.

In cells transfected with siRNA control, immunostaining revealed numerous mature stage III or IV melanosomes concentrating Tyrpl proteins. In contrast, cells transfected with siRNA-μlA, in which the AP-I adapter complex was thus inactivated, contained only stage I or IL immature melanosomes. No mature melanosomes were visible in these cells. The Tyrpl enzyme was always detected by the antibody but was present only in vesicular structures with endosome characteristics and no pigment. These observations therefore indicate that the inactivation of the AP-I complex disrupts the transfer of the melanogenesis enzymes in the pre-melanosomes and thus blocks the maturation of these organelles, which are therefore incapable of ensuring the synthesis of melanin.

Conclusion

The results obtained by these experiments made it possible first of all to observe that the use of specific siRNA makes it possible to inactivate the AP-I complex in the melanocytes. It has furthermore been demonstrated that the inactivation of a single subunit of the AP-1 adapter complex is sufficient to destabilize and thus inactivate said complex. The results obtained also demonstrate that the use of a subunit-specific siRNA of the AP-I adapter complex makes it possible to significantly reduce:

the quantity of melanin produced in the melanocytes,

the amount of melanocytes containing pigmented mature melanosomes and

the proportion of mature melanosomes (stage III or IV) in the melanocytes. By these experiments, the inventors have therefore demonstrated that the subunit-specific siRNAs of the AP-I adapter complex have a significant effect on the production of melanin pigments and can therefore be effectively used as depigmenting agents.

Bibliographical references

Ausubel et al, 1995, Current Protocols in Molecular Biology, Greene Publishing and Wiley-Interscience.

Braun et al, 2007, Mol. Biol. CeIl, 18, 4921-4931. Egholm et al., 1992, J. Am. Chem. Soc., 114, 1895-1897.

Fanning and Symonds, 2006, RNA Towards Medicine, Handbook of Experimental Pharmacology, eds. Springer.

Kumar et al., 1993, Microbiol. Mol. Biol. Rev, 62, 1415-1434. Maniatis et al, 1982, Molecular cloning, A laboratory Manual, CoId Spring Harbor. Nakagawa et al, 2000, Cell, 103, 569-581.

Osborne et al. Aptamers as therapeutic and diagnostic reagents: problems and prospects. Curr Opin Chem Biol. 1997 Jun; l (l): 5-9

Raposo et al, 1997, Immunogold Labeling of Ultrathin Cryosections: Application in Immunology. In: Handbook of Exp. Immunol., Vol. 4, eds. L. A. Herzenberg, D. Weir, L. A. Herzenberg, and C. Blackwell, Cambridge, MA: Blackwell Science, Inc., 1-11

Raposo et al, 2001, J. Cell Biol. 152, 809-824.

Sambrook et al., 1989, Molecular cloning, A laboratory Manual, CoId Spring Harbor. Seiji et al., 1963, Nature, Mar. 16: 197: 1082-4. Theos et al, 2005, Mol. Biol. CeIl, 16, 5356-5372. Van Den Bossche et al, 2006, Traffic, 7, 769-778.

Claims

claims

A pharmaceutical or cosmetic composition comprising at least one kinesin inhibitor Kif13A, a subunit inhibitor of the AP-I adapter complex, and / or an inhibitor of the interaction between a subunit of the AP-I adapter complex, I or the AP-I complex and kinesin Kif13A.

2. Composition according to claim 1, characterized in that said inhibitor is an inhibitor of kinesin Kifl3A.

3. Composition according to claim 1, characterized in that said inhibitor is an inhibitor of a subunit of the AP-I adapter complex.

4. Composition according to claim 1, characterized in that said inhibitor is an inhibitor of the interaction between a subunit of the AP-I adapter complex or the AP-I complex and kinesin Kif13A.

5. Composition according to any one of claims 1 to 4, characterized in that said inhibitor is a small molecule, an aptamer, an antibody, a nucleic acid or a negative dominant peptide.

6. Composition according to any one of claims 1 to 5, characterized in that said inhibitor is a aptamer, an antibody, a nucleic acid or a negative dominant peptide.

7. Composition according to any one of claims 1 to 6, characterized in that said inhibitor is a nucleic acid comprising a sequence capable of hybridizing specifically with a gene or mRNA encoding a subunit of the AP-adapter complex. I or for kinesin Kif13A and to decrease or suppress the expression of said protein.

8. Composition according to claim 7, characterized in that said nucleic acid is an antisense oligonucleotide or an RNAi, preferably a siRNA.

9. Composition according to claim 5 to 8, characterized in that said nucleic acid has a sequence of 15 to 50 nucleotides, preferably from 15 to 30 nucleotides.

10. Composition according to any one of claims 5 to 9, characterized in that said nucleic acid comprises a sequence selected from the sequences SEQ ID No. 1 to 6 and 11 to 24.

11. Composition according to any one of claims 1 to 10, characterized in that it further comprises one or more other active substances, preferably selected from the group consisting of ellagic acid; arbutin; resorcinol; vitamin C; pantothenate; kojic acid; placental extracts; molecules interfering directly or indirectly with melanotropin (MSH), its receptor or adrenocorticotropic hormone (ACTH); polyols such as glycerine,

Glycol or propylene glycol; vitamins ; keratolytic and / or desquamating agents such as salicylic acid; alpha-hydroxy acids such as lactic acid or malic acid; ascorbic acid; retinoic acid; retinaldehyde; retinol; palmitate, propionate or acetate; anti-glycation agents and / or antioxidants such as tocopherol, thiotaurine, hypotaurine, aminoguanidine,

Thiamine pyrophosphate, pyridoxamine, lysine, histidine, arginine, phenylalanine, pyridoxine, adenosine triphosphate; anti-inflammatory agents; soothing agents and mixtures thereof; chemical or physical sunscreens and deoxyribonucleic or ribonucleic acids, and derivatives thereof.

12. Composition according to any one of claims 1 to 11, characterized in that it is suitable for topical administration.

13. Use of a pharmaceutical composition according to any one of claims 1 to 12, for the preparation of a medicament for the treatment or prevention of a pigment disorder.

The use according to claim 13, characterized in that the pigment disorder is hyperpigmentation.

15. Use of a composition according to any one of claims 1 to 12 as a cosmetic agent.

16. Use according to claim 15, characterized in that said cosmetic agent is a depigmenting agent.