Expression profiling and cellular localization of genes associated with the hair cycle induced by wax depilation

The hair cycle is a highly regulated process controlled by multiple factors. Systematic analysis of gene expression patterns in each stage of the hair cycle would provide information useful for understanding this complicated process. To identify genes associated with the hair cycle, we used DNA microarray hybridization to analyze sequential gene expression patterns in mouse skin following hair cycle synchronization by wax depilation. Messenger RNA levels in mouse skin at various times after depilation were compared with those prior to depilation (resting phase). According to their expression patterns, upregulated genes were categorized into four groups: early anagen, middle anagen, late anagen/early catagen, and middle/late catagen, and processes that take place in each stage were evaluated. We identified 12 new components that are specifically expressed in the hair follicle, 11 genes in anagen including carbonic anhydrase 6, cytokeratin 12, and matrix metalloproteinase-11 in catagen that were confirmed using in situ hybridization. The strategy used here allowed us to identify unknown genes or process previously not suspected to have a role in hair biology. These analyses will contribute to elucidating the mechanisms of hair cycle regulation and should lead to the identification of novel molecular targets for hair growth and/or depilation agents.