FR3143040A1 - Method for prognosis and/or diagnosis of loss of hair density - Google Patents

Abstract

Method for prognosis and/or diagnosis of loss of hair density The present invention relates to a method for prognosis and/or diagnosis of hair density loss, comprising measuring the expression level of at least one gene chosen from 63 specific genes, in a scalp sample of a subject. The present invention also relates to a method of cosmetic treatment of the scalp, a method of identifying compounds that prevent hair loss and/or promote hair growth and/or promote an increase in hair thickness. Finally, the present invention relates to a kit and its use for the identification of a compound that prevents hair loss and/or promotes hair growth and/or promotes an increase in hair thickness. Figure for the abstract: none

Description

Method of prognosis and/or diagnosis of hair density loss

The present invention relates to a method for prognosis and/or diagnosis of hair density loss. The present invention also relates to a method for cosmetic treatment of the scalp, a method for identifying compounds that prevent hair loss and/or promote hair growth and/or promote an increase in hair thickness. Finally, the present invention relates to a kit and its use for identifying a compound that prevents hair loss and/or promotes hair growth and/or promotes an increase in hair thickness.

In humans, hair growth is cyclical and consists of three successive phases: the anagen phase, the catagen phase and the telogen phase. Each hair follicle is therefore constantly renewed, cyclically and independently of the adjacent follicles. The anagen phase or growth phase, during which the hair grows longer, lasts several years. The catagen phase which follows the anagen phase is very short and lasts only a few weeks. During this phase, the hair undergoes involution, the follicle atrophies and its dermal implantation appears higher and higher. The telogen phase, which lasts a few months, corresponds to a period of rest of the follicle where the hair ends up falling out. After this rest phase a new follicle is regenerated, on site, and a new cycle begins again.

At any given moment, not all hairs are in the same phase at the same time. Thus, of the approximately 150,000 hairs in a head of hair, only about 10% of them are at rest and will therefore be replaced in a few months according to a biological clock specific to each hair.

Natural hair loss or shedding can be estimated, on average, at a few hundred hairs per day for a normal physiological state. However, it happens that the hair cycle can become disrupted and hair loss accelerates and leads to temporary or permanent hair loss called alopecia. Different causes can be at the origin of alopecia.

It can be a massive loss or alterations of the hair called telogen effluvium , during pregnancy, during states of malnutrition or dietary imbalances, or during states of asthenia, hormonal dysfunction or hormonal changes as can be the case during menopause. It can also be hair loss or alterations related to seasonal phenomena. In certain scalp dermatoses with inflammatory characteristics, such as psoriasis or seborrheic dermatitis, hair loss can be greatly accentuated or lead to severely disrupted follicle cycles.

It can also be alopecia which is essentially due to a disruption in hair renewal which initially leads to an acceleration in the frequency of cycles at the expense of the quality of the hair and then its quantity. The successive growth cycles result in increasingly fine and increasingly shorter hair, gradually transforming into non-pigmented down. Areas are preferentially affected, in particular the temporal or frontal gulfs in men, and in women, there is diffuse alopecia of the vertex. This is more particularly androgenic alopecia. In a significant number of cases, early hair loss occurs in genetically predisposed subjects, this is then androgenetic alopecia; this form of alopecia more preferentially affects men. It is also known that certain factors such as hormonal imbalance, physiological stress or malnutrition can accentuate the phenomenon.

There is therefore a need for new biomarkers allowing the characterization of a loss of hair density, in particular linked to hair loss and/or hair thinning.

There is also a need for a method of screening active ingredients for hair loss prevention and/or hair growth promotion and/or hair thickness enhancement.

The present invention aims to meet this need.

The present invention results from the unexpected discovery by the inventors that a certain number of specific genes, identified below, are involved in the loss of hair density, in particular linked to hair loss and/or thinning of hair.

1. mesurer le niveau d’expression d’au moins un gène choisi parmi les 63 gènes suivants, dans un échantillon de cuir chevelu dudit sujet :

The present invention thus relates to a method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject, said method comprising the following step:

1. measuring the level of expression of at least one gene chosen from the following 63 genes, in a scalp sample from said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

The present invention also relates to a method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject, said method comprising the following steps:

a. measure the level of expression of at least one gene chosen from the following 63 genes, in a scalp sample from said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;

b. deducing from step a) whether the scalp of said subject exhibits a loss of hair density or whether the scalp of said subject is likely to develop a loss of hair density; then

c. if the scalp is identified as having hair loss or as being likely to develop hair loss in step b), treating said scalp with a cosmetic composition against hair loss.

The present invention also relates to a method for identifying an anti-hair loss compound and/or a compound promoting hair growth and/or a compound promoting an increase in hair thickness, said method comprising the following steps:

a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT;

b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and

c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when a decrease in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound.

The present invention also relates to a method for identifying an anti-hair loss compound and/or a compound promoting hair growth and/or a compound promoting an increase in hair thickness, said method comprising the following steps:

a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:

TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16- 1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;

b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and

c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when an increase in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound.

The present invention also relates to a kit comprising:

a. a means for measuring in a scalp sample, the level of expression of at least one gene selected from the following 63 genes, in a scalp sample of said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72, and

b. an instruction manual.

The present invention also relates to the use of a kit according to the invention for the identification of an anti-hair loss compound and/or promoting hair growth and/or promoting an increase in hair thickness.

The present invention also relates to the use of a kit according to the invention for the prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject.

All methods described in the present invention are in vitro methods.

Detailed description of the invention

Met prognosis and/or diagnosis method

The present invention thus relates to a method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject, said method comprising the following step:

a. measure the level of expression of at least one gene chosen from the following 63 genes, in a scalp sample from said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

“Hair density” of a scalp means the number of hairs per square centimeter (cm²) of that scalp. Average hair density is typically greater than 220 hairs/cm². Low hair density is typically less than or equal to 200 hairs/cm², preferably less than or equal to 190 hairs/cm², preferably less than or equal to 185 hairs/cm².

The method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, according to the invention, comprises a step a) of measuring the level of expression of at least one gene chosen from the following 63 genes, in a sample of scalp of said subject: CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

Preferably, step a) comprises measuring the expression levels of at least 2 genes, preferably at least 3 genes, preferably at least 5 genes, preferably at least 10 genes, preferably at least 15 genes, preferably at least 20 genes, preferably at least 30 genes, preferably all genes, selected from the following 63 genes, in a scalp sample of said subject: CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

CCL23 is the gene encoding the chemokine “Chemokine (C-C motif) ligand 23”. The human gene has NCBI accession number ID 6368.

CD300C is the gene encoding CMRF35-like molecule 6 (CLM-6). The human gene has NCBI accession number ID 10871.

CCL8 is the gene encoding the chemokine “C-C motif chemokine 8”. The human gene has NCBI accession number ID 6355.

C7 is the gene encoding the complement component C7. The human gene has NCBI accession number ID 730.

FCN1 is the gene encoding ficolin 1 (in English "ficolin-1"). The human gene has accession number ID 2219 in the NCBI bank.

FCER1G is the gene encoding the high affinity immunoglobulin epsilon receptor subunit gamma. The human gene has NCBI accession number ID 2207.

CCL24 is the gene encoding the chemokine “C-C motif chemokine 24”. The human gene has NCBI accession number ID 6369.

FCGR2A is the gene encoding the low affinity immunoglobulin gamma Fc region receptor II-a (LARI). The human gene has NCBI accession number ID 2212.

VSIG4 is the gene encoding V-set and immunoglobulin domain-containing protein 4. The human gene has NCBI accession number ID 11326.

PPBP is the gene encoding platelet basic protein. The human gene has NCBI accession number ID 5473.

CD14 is the gene encoding the monocyte differentiation antigen CD14 protein. The human gene has NCBI accession number ID 929.

C3AR1 is the gene encoding the anaphyllatoxin chemotactic receptor C3a. The human gene has NCBI accession number ID 719.

IFITM1, IFITM2 or IFITM3 are the genes encoding interferon-induced transmembrane protein 1, 2 or 3, respectively. The human genes have NCBI accession numbers ID 8519 (IFITM1), 10581 (IFITM2) and 10410 (IFITM3).

SPP1 is the gene encoding sphingosine-1-phosphate phosphatase 1. The human gene has NCBI accession number ID 81537.

TIMP4 or TIMP1 are the respective genes encoding metalloproteinase inhibitor 4 or 1. The human genes have NCBI accession ID 7079 or 7076.

PCOLCE is the gene encoding “procollagen C-endopeptidase enhancer-1”. The human gene has NCBI accession number ID 5118.

POSTN is the gene encoding periostin. The human gene has NCBI accession number ID 10631.

DPT is the gene encoding dermatopontin. The human gene has NCBI accession number ID 1805.

TDGF1 is the gene encoding teratocarcinoma-derived growth factor 1. The human gene has NCBI accession number ID 6997.

POU5F1 is the gene encoding POU domain class 5 transcription factor 1. The human gene has NCBI accession number ID 5460.

RUNX2 is the gene encoding Runt-related transcription factor 2. The human gene has NCBI accession number ID 860.

LIN28A is the gene encoding the protein “protein lin-28 homolog A”. The human gene has accession number ID 79727 in the NCBI bank.

ANGPTL3, ANGPTL4 or ANGPTL7 are the genes encoding angiopoietin-related protein 3, 4 or 7, respectively. The human genes have NCBI accession numbers 27329 (ANGPTL3), 51129 (ANGPTL4) and 10218 (ANGPTL7).

KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4- 9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10- 2, KRTAP10-11 and KRTAP10-10, are all proteins associated with keratin. In NCBI, the human genes have accession numbers ID 81870 (KRTAP9-9), 100507608 (KRTAP9-6), 337878 (KRTAP7-1), 387266 (KRTAP5-9), 57830 (KRTAP5-8), 440050 ( KRTAP5-7), 439915 (KRTAP5-5), 387267 (KRTAP5-4), 387266 (KRTAP5-3), 440021 (KRTAP5-2), 440051 (KRTAP5-11), 387273 (KRTAP5-10), 100132386 (KRTAP4 -9), 81871 (KRTAP4-6), 85289 (KRTAP4-5), 84616 (KRTAP4-4), 85291 (KRTAP4-2), 83755 (KRTAP4-12), 653240 (KRTAP4-11), 85285 (KRTAP4-1), 83897 (KRTAP3-2), 85294 ( KRTAP2-4), 728279 (KRTAP2-2), 100505753 (KRTAP16-1), 386676 (KRTAP10-9), 386681 (KRTAP10-8), 386675 (KRTAP10-7), 386682 (KRTAP10-3), 386679 (KRTAP10-2), 386678 (KRTAP10-11) and 353333 (KRTAP10-10).

KRT4, KRT32, KRT39, and KRT72 are also keratin proteins. In NCBI, the human genes have accession numbers ID 3851 (KRT4), 3882 (KRT32), 390792 (KRT39), and 140807 (KRT72).

The genes according to the invention are typically involved in inflammation and/or immunity, and/or in the differentiation of keratinocytes. In particular, they are involved in inflammation, in the extracellular matrix, in the formation or development of stem cells, and/or in the keratinization of hair.

The expression level of a gene refers to the amount of mRNA produced, or the amount of protein produced, by the expression of that gene. This amount can be expressed, for example, as a concentration or as a ratio.

The expression level of each gene can be measured by any suitable technique known in the prior art. To measure mRNA expression, RNAs can be extracted by any method for extracting RNA from skin such as scalp, for example by the method described in the Materials and Methods section of the example below, and then can be processed for specific quantification of mRNA by any method for quantifying mRNA, for example by quantitative PCR. To measure protein expression, proteins can be extracted using a buffer suitable for extracting proteins from skin, for example a RIPA buffer or a urea buffer, and then can be processed by any method for evaluating specific proteins, for example Western blot or ELISA.

The scalp sample of the subject used in the prognosis and/or diagnosis method according to the invention is a sample taken from the scalp of the subject, in particular from the vertex.

By "subject" here is meant a human being, preferably aged 20 to 80 years, preferably aged 50 to 75 years, even better aged 65 to 75 years.

In a particular embodiment, the prognosis and/or diagnosis method according to the invention further comprises the steps consisting of:

b. deducing from step a) whether the scalp of said subject exhibits a loss of hair density or whether the scalp of said subject is likely to develop a loss of hair density; and

c. if the scalp is identified as having hair loss or as being likely to develop hair loss in step b), treating said scalp with a cosmetic composition against hair loss.

By "likely to develop hair loss" is meant a subject who has the onset of hair loss; it also means a subject with a scalp without symptoms of hair loss type.

In a particular embodiment, the scalp of said subject is diagnosed as exhibiting a loss of hair density or likely to develop a loss of hair density, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is modulated, in particular significantly modulated, compared to a control.

In a particular embodiment, the control is a reference value.

In a particular embodiment, the reference value is determined by the average value of the level of expression of a gene, measured in a specific population, for example a population in a specific age range, and/or having a defined scalp type.

Preferably, the scalp of said subject is diagnosed as having a loss of hair density or likely to develop a loss of hair density, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is higher, in particular significantly higher, than a control, said gene(s) being chosen from CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT. Preferably, for each gene, the control is a reference value determined by the average value of the level of expression of the gene, measured in a given population, for example a population aged 50 to 75 years, and/or having an average hair density.

Preferably, the scalp of said subject is diagnosed as having hair density loss or likely to develop hair density loss, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is at least 1.2 times, preferably at least 1.25 times, higher than a control, said gene(s) being selected from CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT.

Preferably, the scalp of said subject is diagnosed as having a loss of hair density or likely to develop a loss of hair density, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is lower, in particular significantly lower, than a control, said gene(s) being selected from TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72. Preferably, for each gene, the control is a reference value determined by the average value of the level of expression of the gene, measured in a given population, for example a population aged 50 to 75 years, and/or having an average hair density.

Preferably, the scalp of said subject is diagnosed as having hair density loss or likely to develop hair density loss, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is at least 1.2 times, preferably at least 1.25 times, lower than a control, said gene(s) being selected from TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

In a particular embodiment, the reference value is determined by a ROC study (“The ROC (receiver operating characteristic) curve: principles and main applications in clinical biology”, H. Delacour et al., Ann Biol Clin 2005; 63 (2): 145-54).

For the purposes of the invention, “significantly higher” and “significantly lower” means a statistically significant variation in the level of expression of a given gene.

Cosmetic treatment method

The present invention also relates to a method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject, said method comprising the following steps:

a. measure the level of expression of at least one gene chosen from the following 63 genes, in a scalp sample from said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;

b. deducing from step a) whether the scalp of said subject exhibits a loss of hair density or whether the scalp of said subject is likely to develop a loss of hair density; and

c. if the scalp is identified as having hair loss or as being likely to develop hair loss in step b), treating said scalp with a cosmetic composition against hair loss.

The measurement in step a) is preferably carried out as described in the section “ Prognostic and/or diagnostic method ” above.

The scalp sample from said subject and the subject may be as described in the “ Prognostic and/or diagnostic method ” section above.

By “cosmetic composition against hair loss” we mean here any type of cosmetic composition (topical or oral for example) intended to improve hair density and/or reduce hair loss and/or hair thinning.

The cosmetic composition may be applied by any suitable route of administration, in particular topically or orally. Preferably, the cosmetic composition is leave-in. It may be presented, for example, in the form of a lotion, a hair mask or a conditioner or cream.

Cosmetic compositions allowing the increase of hair density and/or the reduction of hair loss and/or the thinning of hair, may comprise at least one anti-hair loss active ingredient such as minoxidil.

In a particular embodiment, the scalp of said subject is diagnosed as having a loss of hair density or likely to develop a loss of hair density, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is higher, in particular significantly higher, than a control, said gene(s) being chosen from CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT.

Preferably, the scalp of said subject is diagnosed as having a loss of hair density or likely to develop a loss of hair density, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is lower, in particular significantly lower, than a control, said gene(s) being selected from TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

Method for identifying a compound anti-hair loss and/or promoting hair growth and/or promoting increased hair thickness

The present invention also relates to a method for identifying an anti-hair loss compound and/or a compound promoting hair growth and/or promoting an increase in hair thickness, said method comprising the following steps:

a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT;

b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and

c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when a decrease in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound.

The present invention also relates to a method for identifying an anti-hair loss compound and/or a compound promoting hair growth and/or a compound promoting an increase in hair thickness, said method comprising the following steps:

a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:

TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16- 1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;

b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and

c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when an increase in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound.

The identification method of the invention is preferably carried out ex vivo .

According to one embodiment, the scalp sample used in the identification method according to the invention is a sample taken, invasively or non-invasively, from the scalp of a subject having low hair density.

The measurement in step a) is preferably carried out as described in the section “ Prognostic and/or diagnostic method ” above.

In one variant, the invention relates to a method for evaluating the effectiveness of a cosmetic treatment against hair loss and/or reduction in hair thickness in a subject, said method comprising, after a step of applying the cosmetic composition, a step (a) of measuring at least one gene, in a sample of scalp from said subject.

Preferably this evaluation method further comprises the steps of:

b. compare the said quantity measured in step a) with a control;

c. determine whether said cosmetic treatment against hair loss and/or promoting hair growth and/or promoting an increase in hair thickness is effective in said subject.

The method for evaluating efficacy is preferably implemented in vitro or ex vivo .

The subject is preferably a human being. The subject is preferably between 20 and 80 years old, preferably between 40 and 75 years old, preferably between 60 and 75 years old.

The scalp sample from said subject may be as described in the “ Prognostic and/or diagnostic method ” section above.

The measurement in step a) is preferably carried out as described in the section “ Prognostic and/or diagnostic method ” above.

In a particular embodiment, the control is the level of expression of the gene in a scalp sample of said subject prior to application of said cosmetic treatment.

Preferably, said cosmetic treatment is evaluated as being effective in said subject, if the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is lower, in particular significantly lower, than the control, said gene(s) being chosen from CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT.

Preferably, said cosmetic treatment is evaluated as being effective in said subject, if the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is higher, in particular significantly higher, than the control, said gene(s) being chosen from TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72.

Kit

The present invention relates to a kit comprising:

a. a means for measuring in a scalp sample, the level of expression of at least one gene selected from the following 63 genes, in a scalp sample of said subject:

CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10- 3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72, and

b. an instruction manual.

By “means for measuring in a scalp sample, the level of expression of at least one gene” is meant a means for quantifying the expression of said gene.

In a particular embodiment of the invention, this means is a microfluidic cartridge comprising at least one antibody specific to one of the proteins expressed by one of the genes. This means may also be a means for measuring the expression of the mRNA expressed by one of the genes.

The invention also relates to the use of a kit according to the invention for the identification of an anti-hair loss compound and/or promoting hair growth and/or promoting an increase in hair thickness.

The present invention also relates to the use of a kit according to the invention for the prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject.

The present invention will be described in more detail by the examples below.

Example : Diagnostic/prognostic method of aging scalp, especially scalp with chronological hair loss and thinning hair

Materials and methods

Clinical samples

A single-center case-control clinical study with blinded clinical assessments was conducted at the Sabouraud Health Center (Paris, France). All volunteers were informed of the study objectives and were included after providing written informed consent and granting their rights to the different analyses. The protocol complied with the Declaration of Helsinki and was approved by the local ethics committee (EudraCT#2014-A01704-43 approved by the Comité de Protection des Personnes Ile de France IV).

All study participants were healthy female volunteers or those with no active unstable disease (no change in treatment in the 3 months prior to study participation), aged 65 to 75 years, with skin phototype II or III according to the Fitzpatrick classification, who agreed not to dye their hair for the entire duration of the study and who had last colored or dyed their hair more than 10 days prior to inclusion. Women taking or having taken anti-hair loss treatment in the past were excluded from the study, as were subjects with severe alopecia (type II or type III according to the Ludwig scale).

Subjects were randomized to one of the study groups based on hair density at baseline: high hair density (HD) group for subjects with hair density greater than 220/cm² or low hair density (LD) group for subjects with hair density less than 185/cm².

Scalp images (0.651 cm²) were acquired on the vertex using Fotofinder Medicam immediately after hair cutting and 48 h later. Quality checks performed during the first weeks of the study showed that the quality of the automated image analysis software (Trichoscan v1.1) was not good on this population with a lot of white hair, despite several efforts to improve contrast using hair dye. It was therefore decided that for inclusion purposes, a manual hair count performed on the reference image would be used to confirm total hair density and assign volunteers to the high hair density (HD) or low hair density (LD) groups. A more detailed analysis was done using the Tiff counting method (phototrichogram reference) to determine anagen and telogen hair density (in hairs/cm²). Fine hair (<40µm in diameter) and terminal hair were counted separately.

The volunteers' skin was assessed by a dermatologist who noted the scalp and skin type (oily/dry), various elements of hair quality (density, volume, thickness, diversity of diameter (de Lacharrière, Deloche et al. 2001), percentage of gray hair, length, curliness, presence of damaged hair split ends), scalp assessments (dandruff, atrophic signs such as cupules or halos, presence of telangiectasias) and the presence and severity of signs of photoaging on the face (elastosis, hyperpigmentation, actinic keratosis, seborrheic keratosis, cherry hemangioma).

Sebum level was assessed using a sebumeter (Courage & Khazaka) on the scalp (vertex) and forehead. The areas were then degreased with a cotton pad soaked in ethanol (70°) and the sebum excretion rate was measured 30 min later on the forehead and 48 h later on the scalp.

Volunteers also completed a self-assessment questionnaire with questions about their hair, scalp and skin type and quality, as well as questions about their health and lifestyle (medical history, diet, cosmetic habits, smoking, sun exposure history).

RNA sequencing

Scalp biopsies, 2.5 mm in diameter, were taken from the vertex area of the scalp of each volunteer and used for gene expression profiling (RNA sequencing). The biopsies were placed in Qiagen tubes containing 1 ml of RNA Later buffer (QIAGEN 76106) and transported to the laboratory where the epidermis was isolated within 24 hours of collection.

RNA isolation

Total RNA was isolated from samples with the RNeasy kit (Qiagen, Germantown, MD). RNA purity and integrity were assessed on the Agilent 2100 Bioanalyzer with the RNA 6000 NanoLabChip reagent set (Agilent Technologies, Palo Alto, CA) and the Nanodrop spectrophotometer (ThermoScientific, Wilmington, DE). All samples had RNA integrity number values >7.

Preparation of bank s and RNA sequencing

Library preparation and RNA sequencing were performed as described in the Illumina TruSeq stranded mRNA User Guide (Illumina Inc., San Diego, CA, USA). Briefly, the first step was to purify poly-A-containing mRNA molecules from 1 µg of total RNA using magnetic beads attached to poly-T oligos. After purification, mRNA was fragmented into small pieces using divalent cations at elevated temperature. The cleaved RNA fragments were copied into first-strand cDNA using reverse transcriptase and random primers. The cDNA fragments were then purified with Agencourt AMPure XP beads (Beckman Coulter, Missisauga, Ontario, Canada) and enriched with 13 cycles of PCR to create the final cDNA library. cDNA quality was assessed on the TapeStation 2200 (Agilent technologies, Santa Clara, CA, USA) and the library was quantified using the Qbit 3.0 fluorometer (ThermoFischer Scientific, Canada). Equimolar amounts of each library were sequenced on a HiSeq 2500 instrument (Illumina Inc., San Diego, CA, USA), for 125-nucleotide paired-end sequencing.

Bioinformatics analyses

Raw read quality was assessed using FastQC (v0.11.2) and MultiQC (v1.3). Transcript expression quantification was performed from raw read data (raw counts) using Kallisto (v0.43.1). To generate normalized signals, raw count values were transformed to TPM (Transcript per Million) using Kallisto, or to FPKM (Fragments Per Kilobase per Million aligned reads) using R scripts (v.3.4.0). Differential expression analyses were first calculated using the standard DESeq2 package (v1.16.1) (Love et al., 2014: Love, M.I., Huber, W., & Anders, S. 2014. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biology 15, 550), which returns the results table with log2 change and Wald test p-values (adjusted by the Benjamini-Hochberg (BH) method and unadjusted).

Results

Selected genes who are modulated in scalp with low hair density (compared to normal (high) hair density) that can be used for diagnosis c scalp

Differential expression analysis between LD and HD scalps identified 63 relevant genes, which are as follows:

Genes (15) involved in inflammation

Embarrassed Fold change V al eur p adjusted CCL23 1.37 1.36E-02 CD300C 1.36 1.00E-02 CCL8 1.35 2.01E-02 C7 1.35 1.02E-02 FCN1 1.33 2.54E-02 FCER1G 1.33 1.03E-02 CCL24 1.32 2.87E-02 FCGR2A 1.32 1.46E-02 VSIG4 1.3 1.41E-02 PPBP 1.29 4.24E-02 CD14 1.27 2.11E-02 C3AR1 1.27 3.94E-02 IFITM2 1.27 2.57E-02 IFITM1 1.27 9.24E-03 IFITM3 1.26 1.40E-02

Genoa (6) involved in the extracellular matrix

Embarrassed Fold change Adjusted p-value SPP1 1.46 9.57E-04 TIMP4 1.43 3.10E-03 TIMP1 1.42 1.67E-03 PCOLCE 1.42 1.06E-03 POSTN 1.30 1.96E-02 DPT 1.28 7.34E-03

Genoa (7 ) involved in the the formation or development of stem cells

Embarrassed Fold change Adjusted p-value TDGF1 -1.31 3.16E-02 POU5F1 -1.40 2.89E-03 RUNX2 -1.38 3.98E-04 LIN28A -1.29 2.59E-02 ANGPTL7 -1.42 3.69E-03 ANGPTL4 -1.26 4.84E-02 ANGPTL3 -1.29 4.96E-02

Genoa (35) involved in the hair keratinization

Embarrassed Fold change Adjusted p-value KRTAP9-9 -1.26 4.32E-02 KRTAP9-6 -1.31 4.06E-02 KRTAP7-1 -1.25 2.24E-02 KRTAP5-9 -1.32 2.35E-02 KRTAP5-8 -1.44 4.19E-03 KRTAP5-7 -1.33 2.44E-02 KRTAP5-5 -1.30 3.95E-02 KRTAP5-4 -1.43 4.19E-03 KRTAP5-3 -1.28 4.84E-02 KRTAP5-2 -1.39 1.13E-02 KRTAP5-11 -1.37 9.49E-03 KRTAP5-10 -1.37 1.07E-02 KRTAP4-9 -1.43 4.71E-03 KRTAP4-6 -1.29 3.98E-02 KRTAP4-5 -1.37 3.61E-03 KRTAP4-4 -1.39 4.04E-03 KRTAP4-2 -1.32 1.20E-02 KRTAP4-12 -1.55 5.00E-04 KRTAP4-11 -1.29 1.86E-02 KRTAP4-1 -1.28 3.79E-02 KRTAP3-2 -1.25 3.80E-02 KRTAP2-4 -1.42 2.83E-03 KRTAP2-2 -1.33 1.90E-02 KRTAP16-1 -1.42 3.69E-03 KRTAP10-9 -1.32 1.04E-02 KRTAP10-8 -1.30 2.97E-02 KRTAP10-7 -1.43 2.83E-03 KRTAP10-3 -1.29 4.11E-02 KRTAP10-2 -1.33 2.15E-02 KRTAP10-11 -1.37 6.62E-03 KRTAP10-10 -1.32 2.02E-02 KRT72 -1.29 4.93E-02 KRT4 -1.30 2.65E-02 KRT39 -1.32 2.31E-02 KRT32 -1.35 1.68E-02

These genes represent scalp markers characteristic of hair thinning status and can be used to diagnose scalp condition with respect to hair thinning (and/or hair loss).

Diagnostic methods

A scalp sample is taken from the subject (epilated hair, scalp biopsy). Diagnosis is based on the assessment of the level of expression of specific markers, either at the mRNA level or at the protein level.

For mRNA level assessment, RNAs are extracted by any skin RNA extraction method, e.g. the method described in the Materials and Methods section above, and then processed for specific mRNA quantification by any mRNA quantification method, e.g. by quantitative PCR. The expression level of the marker of interest is then compared to the expression level of the housekeeping genes.

For protein level assessment, proteins are extracted using a buffer suitable for skin protein extraction, e.g. RIPA buffer or urea buffer, and then processed by any specific protein assessment method, e.g. Western blot or ELISA. The expression level of the marker is compared to a reference protein (similar to housekeeping genes).

Claims (12)

Method for prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject, said method comprising the following steps:
a. measuring the level of expression of at least one gene chosen from the following 63 genes, in a scalp sample from said subject:
CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;
b. deducing from step a) whether the scalp of said subject exhibits a loss of hair density or whether the scalp of said subject is likely to develop a loss of hair density; and
c. if the scalp is identified as having hair loss or as being likely to develop hair loss in step b), treating said scalp with a cosmetic composition against hair loss. The method of claim 1, wherein the scalp of said subject is diagnosed as having hair density loss or likely to develop hair density loss, when the level of expression of the gene(s) measured in step a) in the scalp sample of the subject is higher, in particular significantly higher, than a control, said gene(s) being selected from CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT. The method of claim 1, wherein the scalp of said subject is diagnosed as having hair density loss or susceptible to developing hair density loss, when the level of expression of the gene(s) measured in step (a) in the scalp sample of the subject is lower, in particular significantly lower, than a control, said gene(s) being selected from TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72. Method according to claim 2 or 3, in which, for each gene, the control is a reference value determined by the average value of the level of expression of the gene, measured in a given population, for example a population aged 50 to 75 years, and/or having an average hair density. Method according to one of claims 1 to 4, in which the cosmetic composition against loss of hair density comprises at least one anti-hair loss active ingredient such as minoxidil. Method for identifying a compound that prevents hair loss and/or promotes hair growth and/or promotes an increase in hair thickness, said method comprising the following steps:
a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:
CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN and DPT;
b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and
c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when a decrease in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound. Method for identifying a compound that prevents hair loss and/or promotes hair growth and/or promotes an increase in hair thickness, said method comprising the following steps:
a. contacting at least one candidate compound with a scalp sample from a subject, then measuring the level of expression of at least one gene selected from the following genes, in said sample:
TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72;
b. comparing the expression measured in step a) to the expression of the same gene(s) in a scalp sample not exposed to said compound; and
c. identifying said candidate compound as an anti-hair loss or hair growth promoting compound, or promoting an increase in hair thickness, when an increase in the expression of the gene(s) in the scalp sample that has been exposed to said candidate compound is detected, compared to the expression of the gene(s) in the scalp sample that has not been exposed to the candidate compound. Method according to one of the preceding claims, in which the level of expression of a gene is either the quantity of mRNA produced, or the quantity of protein produced, by the expression of this gene. Method according to one of the preceding claims, in which the level of expression of each gene is measured by quantitative PCR, or Western blot or ELISA. Kit including:
a. a means for measuring in a scalp sample, the level of expression of at least one gene selected from the following 63 genes:
CCL23, CD300C, CCL8, C7, FCN1, FCER1G, CCL24, FCGR2A, VSIG4, PPBP, CD14, C3AR1, IFITM1, IFITM2, IFITM3, SPP1, TIMP4, TIMP1, PCOLCE, POSTN, DPT, TDGF1, POU5F1, RUNX2, LIN28A, ANGPTL3, ANGPTL4, ANGPTL7, KRTAP9-9, KRTAP9-6, KRTAP7-1, KRTAP5-9, KRTAP5-8, KRTAP5-7, KRTAP5-5, KRTAP5-4, KRTAP5-3, KRTAP5-2, KRTAP5-11, KRTAP5-10, KRTAP4-9, KRTAP4-6, KRTAP4-5, KRTAP4-4, KRTAP4-2, KRTAP4-12, KRTAP4-11, KRTAP4-1, KRTAP3-2, KRTAP2-4, KRTAP2-2, KRTAP16-1, KRTAP10-9, KRTAP10-8, KRTAP10-7, KRTAP10-3, KRTAP10-2, KRTAP10-11, KRTAP10-10, KRT4, KRT32, KRT39 and KRT72, and
b. an instruction manual. Use of a kit according to claim 10 for the identification of an anti-hair loss compound and/or promoting hair growth and/or promoting an increase in hair thickness. Use of a kit according to claim 10 for the prognosis and/or diagnosis of a loss of hair density, in particular linked to hair loss and/or thinning of hair, in a subject.