Skin pigmentation and its control: From ultraviolet radiation to stem cells.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic biology without systematic search criteria or original empirical data.
PubMed 33320376 · doi:10.1111/exd.14260
What was done
This review summarized the current mechanistic understanding of epithelial and follicular pigmentation biology based on published literature. It detailed key pathways including ultraviolet radiation-induced delayed tanning, melanocortin 1 receptor signaling, hair bulge melanocyte stem cell dynamics in vitiligo repigmentation, and physiological or stress-accelerated hair greying.
What was found
The abstract reports qualitative biological mechanisms rather than quantitative numerical data. UVB-induced keratinocyte DNA damage activates p53-mediated pro-opiomelanocortin (POMC) expression, yielding alpha-melanocyte-stimulating hormone (which acts on MC1R to drive MITF expression and melanogenesis) and beta-endorphin (which promotes UV-seeking behavior). Additionally, UVB phototherapy drives hair bulge melanocyte stem cell differentiation and migration for perifollicular repigmentation in vitiligo, whereas melanocyte stem cell depletion or acute sympathetic hyperproliferation leads to hair greying.
Why it matters
Mapping the regulatory pathways of melanocyte stem cells and UV response clarifies the pathogenesis of pigmentation disorders and skin malignancies while highlighting potential molecular targets for vitiligo and hair greying.
Limits
The abstract provides no quantitative metrics, meta-analytic data, or search strategy details. As a narrative review, it describes molecular pathways largely derived from mechanistic models, with specific human clinical efficacy and safety of targeted interventions not quantified.
Cited by
- supports UV light causes DNA breaks in skin cells, which activates p53 to bind DNA and produce the prohormone pro-opiomelanocortin (POMC).