Modulation of elastin exon 26A mRNA and protein expression in human skin in vivo.

Photoaged skin contains elastotic materials in the upper reticular dermis, a result of a commonly known as solar elastosis. It is known that the primary transcript of elastin undergoes extensive alternative splicing and that this results in the translation of multiple heterogeneous protein isoforms. In this study, we found that UV irradiation and heat treatment increased the levels of elastin transcript containing exon 26A and its encoded elastin isoform in the epidermis of human skin in vivo and in cultured human keratinocytes in vitro.

Reactive oxygen species produced by NADPH oxidase, xanthine oxidase, and mitochondrial electron transport system mediate heat shock-induced MMP-1 and MMP-9 expression.

In addition to ultraviolet radiation, human skin is also exposed to infrared radiation (IR) from natural sunlight. IR typically increases the skin temperature. This study examined whether or not heat shock-induced ROS stimulates MMPs in keratinocyte HaCaT cells.