LRP1 Controls Intracellular Cholesterol Storage and Fatty Acid Synthesis through Modulation of Wnt Signaling.
Résumé
The low-density lipoprotein receptor-related protein LRP1 is a cell surface receptor with functions in diverse physiological pathways, including lipid metabolism. Here we show that LRP1-deficient fibroblasts accumulate high levels of intracellular cholesterol and cholesteryl-ester when stimulated for adipocyte differentiation. We demonstrate that LRP1 stimulates a canonical Wnt5a signaling pathway that prevents cholesterol accumulation. Moreover, we show that LRP1 is required for lipolysis and stimulates fatty acid synthesis independently of the noradrenergic pathway, through inhibition of GSK3beta and its previously unknown target acetyl-CoA carboxylase (ACC). As a result of ACC inhibition, mature LRP1-deficient adipocytes of adult mice are hypotrophic, and lower uptake of fatty acids into adipose tissue leads to their redistribution to the liver. These results establish LRP1 as a novel integrator of adipogenic differentiation and fat storage signals.