Objectives: Hyperandrogenism is usually accompanied with central obesity and metabolic disorders. We aim to elucidate the mechanism underlying hyperandrogenism-evoked expansion of visceral adipose tissue.
Methods: A hyperandrogenic mouse model was established by chronic dihydrotestosterone (DHT) infusion. The metabolic phenotypes were measured. The non-immune cell fraction in gonadal adipose stromal vascular cells were subjected to 10x single-cell seq. Mesothelial cells were isolated using FACS. ER stress was measured by qPCR. Androgen receptor-regulated genes were profiled by CUT&Tag. White adipose tissue organoids were cultured by suspension culture. Tissue or organoid ECM content was measured by Sirius red staining and hydroxyproline assay.
Results: The gonadal white adipose tissue of the hyperandrogenic mice was hypertrophic, but accompanied with a significantly disrupted extracellular matrix (ECM). By single-cell sequencing, we found the number of mesothelial cells was reduced by 50% upon hyperandrogenism, which was experimentally verified by flow cytometry and immunofluorescent staining. The reduction in mesothelial cell number was caused by androgen-evoked induction of Inmt, which in turn enhanced ER stress and apoptosis in mesothelial cells. Mesothelial cells play an essential role in normal formation of ECM, since mesothelial cell null mice exhibited ECM destruction and adipocyte hypertrophy in gonadal white adipose tissue. Furthermore, in visceral adipose organoids, depletion of mesothelial cells caused a loss of ECM, which was restored by supplementation with mesothelial cell conditioned medium. Proteomics analysis on mesothelial cell conditioned medium revealed DCN as a secreted factor by mesothelial cells. DCN expression was reduced in mesothelial cells of DHT mice. Neutralization of DCN abolished the effect of mesothelial cell conditioned medium to enhance ECM formation in organoid culture, demonstrating the key role of DCN in linking mesothelial cell function and ECM formation. Supplementation of DCN in gonadal white adipose tissue of hyperandrogenic mice reversed the central obesity and metabolic disorders.
Conclusions: Mesothelial cell is a major target of androgen and assists ECM formation in visceral adipose tissue.
Funding Sources: This work was supported by Early Career Scheme (24110224).
