Researchers ID proteins benefiting skin

San Diego - A new study offers insight into the role and importance of exosomes and their targeted gene transcripts - information that could lead to new treatments for skin diseases and other disorders.

The study, headed by George L. Sen, Ph.D., assistant professor of cellular and molecular medicine at the University of California, San Diego School of Medicine, explains how human epidermal progenitor and stem cells control transcription factors to avoid premature differentiation, preserving their ability to produce new skin cells throughout life, Newswise.com reports.

 “The exosome functions as a surveillance system in cells to regulate the normal turnover of RNAs as well as to destroy RNAs with errors in them,” Newswise quotes Dr. Sen as saying.

Investigators discovered that in the epidermis, the exosome functions to target and destroy messenger RNAs that encode for transcription factors that induce differentiation. Specifically, they found that the exosome degrades a transcription factor called GRHL3 in epidermal progenitor cells, keeping the latter undifferentiated. Upon receiving differentiation-inducing signals, the progenitor cells lose expression of certain subunits of the exosome which leads to higher levels of GRHL3 protein. This increase in GRHL3 levels promotes the differentiation of the progenitor cells.

“Without a functioning exosome in progenitor cells, the progenitor cells prematurely differentiate due to increased levels of GRHL3, resulting in loss of epidermal tissue over time,” Dr. Sen told Newswise, adding that the study’s findings could have particular relevance if future research determines that mutations in exosome genes are linked to skin disorders or other diseases. “Once mutations in exosome complex genes are identified in either skin diseases or other diseases … it may be possible to design drugs targeting these defects.”

The study was published in the July 6 issue of Cell Stem Cell.

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