Adipocyte-secreted PRELP promotes adipocyte differentiation and adipose tissue fibrosis by binding with p75 to activate FAK/MAPK signaling.

Adipocyte-secreted factors intricately regulate adipose tissue function, and the underlying molecular mechanisms are only partially understood. However, the function of PRELP, which is a key component of the extracellular matrix (ECM) in adipocytes, remains largely unknown. In this study, we demonstrate that PRELP was upregulated in both obese humans and mice, which exhibited a positive correlation with metabolic disorders. PRELP knockout could resist HFD-induced obesity and inhibit adipocyte differentiation. PRELP knockout improved glucose tolerance, insulin sensitivity and alleviated adipose tissue fibrosis. Mechanistically, PRELP was secreted into the ECM and bound to the extracellular domain of its receptor p75 in adipocytes, which further activated the FAK/MAPK (JNK, p38 MAPK, ERK1/2) signaling pathway, promoting adipocyte differentiation and exacerbating adipocyte fibrosis. Adipocyte PRELP plays a pivotal role in regulating obesity and adipose tissue fibrosis through an autocrine manner, and PRELP may be a therapeutic target for obesity and its related metabolic disorders.