Figure 1. A large-scale expression screen identifies microRNAs modulated by aging in human keratinocytes. (A) Hierarchical clustering of miRNA differentially expressed in keratinocytes from four infants (3-6 years), four young adults (20-40 years) or four aged adults (60-71 years). Green color corresponds to underexpression and red color to overexpression. The data are normalized to the first infant sample. (B) QPCR Validation of 6 modulated microRNAs indicated by arrows in the clustering data: miR-30a-3p, miR-30a-5p, miR-30c-2-3p, miR-30c-5p, miR-365a-5p, and miR-4443 expression levels were analyzed by QPCR in 8 independent cultures of keratinocytes from young and aged donors. Results are mean +/- SD from three independent samples. **P<0,01, ***P<0,001.