The present invention provides methods of diagnosing and treating fast aging skin, especially in young subjects, by measuring and/or adjusting a property selected from cell proliferation rate, NFKB1 gene expression, CDKN1A gene expression, CDKN2A gene expression, CEBPB gene expression, and combinations thereof.

Since skin condition is significantly influenced by environmental factors associated with lifestyle habits, it has been difficult to forecast skin condition by means of SNP analysis. The purpose of the present invention is to determine one's congenital skin characteristics, which has been difficult with the prior art. The present invention provides a method for determining not only one's congenital skin characteristics but also future skin type by determining skin condition from genetic and environmental factors.

Methods and systems for constructing a gene expression signature representative of a number of biological conditions, systems and methods for determining functional relationships between a skin-active agent and skin conditions of interest, and methods and systems for identifying skin-active agents with broad spectrum activity are provided.

Provided are methods and systems for determining functional relationships between ex vivo skin models and an inflammatory skin condition. Also provided are methods and systems for identifying modulators of inflammation of skin, as well as the use of modulators identified by such methods or systems for the preparation of cosmetic compositions, personal care products, or both.

The disclosure relates to the identification and the use of compounds which regulate the expression of at least one Sestrin gene, for preventing and/or attenuating skin ageing, and/or for hydrating the skin and/or for regulating skin pigmentation. The method includes the following steps: a. bringing at least one test compound in contact with a sample of human keratinocytes or melanocytes; b. measuring the expression of at least one Sestrin gene chosen from SESN3, SESN2 and SESN1 in the keratinocytes or melanocytes; c. selecting the compounds for which an activation of at least 1.6 fold of the expression of at least one of the genes is measured in the keratinocytes treated in a. compared with the untreated keratinocytes, or for which a significant modulation of the expression of at least one of the genes is measured in the melanocytes treated in a. compared with the untreated melanocytes.

The identification and the use of compounds which activate the expression of at least one gene selected from LARGE, HS6ST2 and ST8SIA1 is provided. An in vitro method for screening for candidate compounds includes: (a) bringing at least one test compound in contact with a sample of keratinocytes in vitro; (b) measuring the expression of at least one gene selected from LARGE, HS6ST2 and ST8SIA1, in the keratinocytes; and (c) selecting the compounds for which an activation of at least 1.4 fold of the expression of at least one of the LARGE, HS6ST2 and ST8SIA1 genes is measured in the keratinocytes treated in (a) compared with the untreated keratinocytes. The candidate compounds may be useful for preventing and/or attenuating ageing, and/or for hydrating skin.

The present invention relates to an in vitro method for identifying agents capable of inducing sensitization of human skin and arrays and diagnostic kits for use in such methods. In particular, the methods include measurement of the expression of the biomarkers listed in Table 3A and/or 3B in MUTZ-3 cells exposed to a test agent.

Methods of identifying potential skin moisturizing actives for the treatment of dry skin and method of formulating a moisturizing skin care composition using actives identified by the method. Moisturizing agents can be identified by comparing the transcriptional profile of a skin tissue sample contacted by a test agent to a negative or positive control to determine if the regulation of certain genes corresponds to the appropriate direction of regulation indicated by the control. Agents identified as skin moisturizing agents can then be incorporated into a skin moisturizing composition.

The present disclosure relates to HAPLN1 protein of an aged individual. The HAPLN1 protein exhibits reduced expression with aging, and when administered, its effect in alleviating and reversing skin aging including wrinkles is excellent. Therefore, by exploiting the difference in expression, provided are a biomarker composition for measuring skin aging, capable of diagnosing skin aging; a kit; and a method of screening for skin aging alleviating agents, comprising detecting the expression level of HAPLN1 protein or HAPLN1 gene. In addition, provided are a pharmaceutical composition, cosmetic composition, or health functional food for preventing or alleviating skin aging, and a cosmetic composition or health functional food for alleviating wrinkles, each containing any one or more selected from the group consisting of HAPLN1 protein, a gene encoding the same, and an effective agent for promoting the expression or activating the functions of HAPLN1 protein or gene.

The present invention relates to a method for identifying the skin sensitizer potency of a test agent, and arrays and analytical kits for use in such methods.