Human adipose-derived stem cell exosomes reduce mitochondrial DNA common deletion through PINK1/Parkin-mediated mitophagy to improve skin photoaging.

Backgroud: Mitochondrial DNA (mtDNA) deletion and oxidative stress are key contributors to skin photoaging. Mitophagy helps mitigate oxidative stress. Human adipose-derived stem cell exosomes (hADSC-Exos) have been shown to counteract skin photoaging. This study aimed to explore the role and mechanism of hADSC-Exos in addressing skin photoaging.

Methods: hADSC-Exos were isolated, and their surface markers were identified. Human dermal fibroblasts (HDFs) and nude mice were exposed to ultraviolet-B (UVB) irradiation, and treated with hADSC-Exos. Oxidative stress and photoaging were assessed through SA-β-gal staining, p21 expression, mtDNA deletion, reactive oxygen species (ROS) levels, and histological analysis. The PINK1, Parkin, LC3b, and p62 protein levels were measured to evaluate mitophagy. The PINK1 small-interfering RNA (siPINK1) was then used in HDFs to investigate the role of hADSC-Exos in mitophagy.

Results: In UVB-exposed HDFs and nude mice, the number of SA-β-gal-positive cells, along with levels of p21, ROS, and mtDNA deletion, were significantly increased, but these effects were reduced by hADSC-Exos. Moreover, hADSC-Exos treatment significantly elevated PINK1 and Parkin levels, as well as the LC3bII/I ratio, while reducing p62 expression. In photoaged HDFs treated with hADSC-Exos, PINK1 knockout using siRNA decreased the LC3bII/I ratio and levels of PINK1 and Parkin, while increasing p62, ROS, and mtDNA deletion compared to the negative control (NC) group.

Conclusion: hADSC-Exos can mitigate skin photoaging by promoting PINK1/Parkin-mediated mitophagy, thereby reducing mtDNA deletion and oxidative stress.