Skin Organoids in Proteostasis Research: Early Insights into Aging.

The decline of proteostasis is a central hallmark of aging, the earliest manifestations of which have remained difficult to capture in human tissues with conventional model systems. The skin is a continuously renewing and environmentally exposed organ offering a uniquely accessible window into aging biology. Skin organoid technologies allow for long-term culturing of human epidermal and full-thickness skin-like tissues that accurately recapitulate important aspects of cellular heterogeneity, spatial organization, and stem cell dynamics. In this perspective, we discuss how skin organoids are beginning to reveal early proteostasis alterations-encompassing impaired protein folding, reduced proteasomal activity, and autophagy dysfunction-that precede overt structural and functional hallmarks of skin aging, with particular emphasis on underexplored regulators- sebaceous gland and sebocyte-specific proteostasis, autophagy, and inflammaging. We also highlight emerging insights, conceptual challenges, and experimental limitations, and outline future directions for integrating skin organoids with skin-on-a-chip, single-cell proteomics, and stress-reporting approaches to advance proteostasis-targeted interventions in skin aging.