Starfish-Derived Extracts Enhance Mitophagy and Suppress Senescence-Associated Markers in Human Dermal Fibroblasts

While the starfish species <i>Asterias pectinifera</i> (<i>Ap</i>) and <i>Asterias amurensis</i> (<i>Aa</i>) are considered ecological threats to marine environments and the fishing industry, recent studies have identified them as rich sources of highly water-soluble, non-toxic collagen peptides. Mitochondrial dysfunction is a key driver of cellular senescence and skin aging, yet the therapeutic potential of marine-derived extracts in modulating mitophagy remains largely unexplored. In this study, we investigated whether starfish-derived extracts could mitigate senescence-associated phenotypes in human dermal fibroblasts (HDFs) through the modulation of mitophagy. Treatment with <i>Ap</i>- or <i>Aa</i>-derived extracts led to reduced senescence-associated β-galactosidase (SA-β-gal) activity, decreased expression of matrix metalloproteinase-1 (MMP-1), and suppression of pro-inflammatory cytokines including interleukin-6 (IL-6) and interleukin-8 (IL-8). <i>Ap</i>- or <i>Aa</i>-derived extracts significantly increased mitophagy in HDFs stably expressing mitochondrial-targeted Keima (HDF-mtKeima), while knockdown of PINK1, the essential regulator of mitophagy, abolished the mitophagy-inducing effects of <i>Ap</i>- or <i>Aa</i>-treatment, indicating that <i>Ap</i>- or <i>Aa</i>-derived extracts activate PINK1/Parkin-dependent mitophagy pathways. Importantly, PINK1 knockdown reversed starfish-induced suppression of MMP-1 and p21, demonstrating its crucial role in regulating senescence-associated gene expression. Additionally, <i>Ap</i> or <i>Aa</i> treatments significantly reduced reactive oxygen species (ROS) accumulation, improved mitochondrial function, and enhanced both basal and maximal respiratory capacity in senescent HDFs. These findings highlight that extracts derived from starfish promote mitophagy through PINK1-dependent mechanisms, exhibiting significant anti-senescence effects in HDFs. This suggests their potential application in the development of novel cosmeceuticals with skin-protective and rejuvenating properties.