CPT1B-Mediated Fatty Acid Oxidation Induces Pigmentation in Solar Lentigo

Cellular senescence is associated with altered lipid metabolism, including increased cellular lipid uptake, upregulated lipid biosynthesis, and deregulated lipid breakdown. Previous studies have reported that carnitine palmitoyltransferase (CPT), the rate-limiting enzyme in fatty acid oxidation that catalyzes the conversion of acyl-CoA to acylcarnitine, is involved in various senescence-related diseases. Although solar lentigo (SL) is an age-related pigmentary disorder characterized by the accumulation of senescent cells, its role in metabolic dysregulation has rarely been investigated. Integrated transcriptomic profiling of SL skin samples, combining mRNA sequencing, differential gene expression, pathway enrichment analyses, metabolic flux simulations, and protein-protein interaction analysis, was conducted to demonstrate the molecular alterations in SL compared to perilesional normal skin. We found transcriptomic alterations in mitochondrial energy metabolism-associated genes. Metabolic flux simulations revealed that carnitine-associated reactions involved in fatty acid oxidation were upregulated. Using a multi-omics approach, CPT1B was selected as a potential marker for SL. Using a zebrafish model, CPT1B was implicated in melanogenesis. CPT1B-mediated metabolic alteration is a key driver of SL pathogenesis. Targeting CPT1B and the associated lipid metabolism pathways is a novel therapeutic approach for managing SL and age-related pigmentation disorders.