Endothelial TrkA Coordinates Vascularization and Innervation in Thermogenic Adipose Tissue and Can Be Targeted to Control Metabolism

Objective: Brown adipogenesis and thermogenesis in brown and beige adipose tissue (AT) involve vascular remodeling and sympathetic neuronal guidance. Here, we investigated the molecular mechanism coordinating these processes.

Methods: We used mouse models to identify the molecular target of a peptide CPATAERPC homing to the endothelium of brown and beige AT.

Results: We demonstrate that CPATAERPC mimics nerve growth factor (NGF) and identify a low molecular weight isoform of NGF receptor, TrkA, as the CPATAERPC cell surface target. We show that the expression of truncated endothelial TrkA is selective for brown and subcutaneous AT. Analysis of mice with endothelium-specific TrkA knockout revealed the role of TrkA in neuro-vascular coordination supporting the thermogenic function of brown adipocytes. A hunter-killer peptide D-BAT, composed of CPATAERPC and a pro-apoptotic domain, induced cell death in the endothelium and adipocytes. This resulted in thermogenesis impairment, and predisposed mice to obesity and glucose intolerance. We also tested if this treatment can inhibit the tumor recruitment of lipids mobilized from adipocytes from adjacent AT. Indeed, in a mouse model of breast cancer D-BAT suppressed tumor-associated AT lipolysis, which resulted in reduced fatty acid utilization by cancer cells.

Conclusion: Our study demonstrates that TrkA signaling in the endothelium supports neuro-vascular coordination enabling beige adipogenesis.