Method for screening skin barrier function enhancing agent based on epidermal serine racemase and/or d-serine level, and skin barrier function evaluation method

Abstract

The object of the invention is to develop a screening method for drugs having effects of increasing skin barrier function in in vitro experimentation, and to evaluate skin barrier function for skin. Serine racemase activity and/or expression level are used as an indicator to allow screening of candidate drugs.

What is claimed is: 
     
         1 . A method for screening a skin barrier function enhancing agent, using the activity or expression level of serine racemase and/or D-serine level in keratinocytes as an indicator. 
     
     
         2 . The screening method according to  claim 1 , comprising:
 adding a candidate drug to keratinocytes;   measuring the activity or expression level of serine racemase and/or the D-serine level in the keratinocytes; and   determining the skin barrier function enhancing effect of the candidate drug based on the activity or expression level of serine racemase and/or the D-serine level.   
     
     
         3 . The screening method according to  claim 2 , further comprising a step of inducing differentiation of the keratinocytes. 
     
     
         4 . The screening method according to  claim 3 , wherein the screening method is conducted in the differentiation-induced keratinocytes. 
     
     
         5 . The screening method according to  claim 1 , wherein the measurement of the serine racemase expression level is carried out by measuring the amount of serine racemase mRNA or protein. 
     
     
         6 . The screening method according to  claim 1 , wherein the measurement of serine racemase activity is carried out by measuring the substrate conversion efficiency by serine racemase, or measuring the amount of D-amino acid product. 
     
     
         7 . A serine racemase activating agent comprising one or more substances selected from the group consisting of hydrolyzed oat protein, Lempuyang extract, and  Elephantopus mollis  extract as an active ingredient, which is obtained by the screening method according to  claim 1 . 
     
     
         8 . A method for evaluating a skin barrier function, using an activity or expression level of serine racemase and/or D-serine level from a skin sample isolated from human skin as an indicator. 
     
     
         9 . The skin barrier function evaluation method according to  claim 8 , comprising:
 measuring the activity or expression level of serine racemase and/or D-serine level in a skin sample isolated from a subject, and   determining the skin barrier function of the subject from the activity or expression level of serine racemase and/or D-serine level.   
     
     
         10 . The skin barrier function evaluation method according to  claim 8 , wherein measurement of the serine racemase expression level is carried out by measuring amounts of mRNA or protein of serine racemase. 
     
     
         11 . The method according to  claim 8 , wherein the measurement of serine racemase activity is carried out by measuring the substrate conversion efficiency or amount of D-amino acid product by serine racemase.