Sarah Mosca, Grazia Bottillo, Enrica Flori, Daniela Kovacs, Miriam Maiellaro, Francesca Lozzi, Alessia Cavallo, Christos C Zouboulis, Giulia Simmini, Alessia Luppino, Claudia Novello, Valentina Leta, Gianfranco Gaudiano, Grazia Devigili, Roberto Eleopra, Fabrizio Tagliavini, Samanta Mazzetti, Emanuela Camera, Giorgia Cardinali
Pathological aggregation of α-synuclein (αSyn) is a hallmark of Parkinson's disease (PD), but increasing evidence indicates that αSyn deposits extend beyond the central nervous system to peripheral tissues, including the skin. In PD patients, cutaneous αSyn accumulation has been associated with seborrheic dermatitis (SD), a chronic inflammatory condition linked to sebocyte dysfunction and altered sebum production. Marked differences in sebum composition between PD patients and healthy controls have been described. We aimed to investigate whether pathological αSyn could contribute to dysregulated sebum production and composition by assessing key markers of sebocyte differentiation and lipogenesis in human sebaceous gland cells and skin biopsies from PD patients (n = 5) and matched controls (n = 5) without clinically recorded SD. O-αSyn exposure of immortalized sebaceous gland cells (SZ95) altered the transcriptional programs related to sebocyte differentiation, inflammation, metabolism, and lipogenesis. Consistently, protein markers of mid-to-late sebocyte differentiation were increased. Upregulation of PLIN2, together with elevated PPARγ, SREBP1, SCD1, and FADS2, indicated progression toward a mature and lipid-producing phenotype characterized by enhanced accumulation of neutral lipids within lipid droplets. Lipidomic profiling revealed remodeling of multiple lipid classes, with increases in triglycerides, ceramides, and selected phospholipids. Increased expression of PLIN2 and PPARγ was also observed in sebaceous glands from PD skin biopsies compared to controls. Collectively, our findings indicate that O-αSyn exposure is associated with molecular changes consistent with altered sebocyte differentiation and lipid remodeling. These results support a potential association between αSyn and lipid dysregulation in sebocytes and suggest that these cells may represent unrecognized peripheral targets of αSyn.