Beiging of perivascular adipose tissue regulates its inflammation and vascular remodeling

Although inflammation plays critical roles in the development of atherosclerosis, its regulatory mechanisms remain incompletely understood. Perivascular adipose tissue (PVAT) has been reported to undergo inflammatory changes in response to vascular injury. Here, we showed that vascular injury induced the beiging (brown adipose tissue-like phenotype change) of PVAT, which fine-tunes inflammatory response and thus vascular remodeling as a protective mechanism. In a mouse model of endovascular injury, macrophages accumulated in PVAT, causing beiging phenotype change. Inhibition of PVAT beiging by genetically silencing PRDM16, a key regulator to beiging, exacerbated inflammation and vascular remodeling following injury. Conversely, activation of PVAT beiging attenuated inflammation and pathological vascular remodeling. Single-cell RNA sequencing revealed that beige adipocytes abundantly expressed neuregulin 4 (Nrg4) which critically regulated alternative macrophage activation. Importantly, significant beiging was observed in the diseased aortic PVAT in patients with acute aortic dissection. Taken together, vascular injury induced the beiging of adjacent PVAT with macrophage accumulation, where NRG4 secreted from the beige PVAT facilitated alternative activation of macrophages, leading to the resolution of vascular inflammation. Our study demonstrated the pivotal roles of PVAT in vascular inflammation and remodeling and will open a new avenue for treating atherosclerosis. Overall design: Tissue: Outer tissues surrounding the murine femoral arteries; 2 conditions: sham vs injury; 2 replicate for each condition.