Mechanosensitive Yes-Associated Protein in Human Skin during Aging

The goal of this work was to examine the level of Yes-associated protein (YAP) in the fibroblasts and blood microvessels of human dermis from development until deep aging (from 20 weeks of pregnancy until 85 years old) and to define the role of YAP in age-dependent changes in the number of fibroblasts and blood microvessels in the dermis. YAP, proliferating cell nuclear antigen (PCNA), endothelial-cell marker CD31 were detected with an indirect immunohistochemical technique. The results showed that the proportion of dermal fibroblasts positively stained for YAP steadily decreased from 20 weeks of pregnancy to 40 years of age. Then, the percent of YAP positive fibroblasts in dermis increased from 41 years of age to the age of 85. The YAP level in blood microvessels of the human dermis were decreasing from 20 weeks of pregnancy until 40 years old, and later it started to increase significantly up to 85 years old. An age-related decrease in the total number and percent of PCNA-positive fibroblasts in the number of blood vessels in the dermis was associated with age-related changes in the YAP content in fibroblasts and blood microvessels, although the change was not statistically significant.