Involvement of brain pericytes in the development of obesity

脑周细胞是血脑屏障（BBB）的周围内皮附属结构，是神经血管单元的组成部分。尽管神经元与神经胶质细胞之间的相互作用对大脑功能至关重要，但周细胞与神经元之间的相互作用尚不清楚。结果表明，在生理条件下，周细胞通过可溶性因子增加下丘脑神经元的胰岛素敏感性，减少AgRP的产生。另一方面，我们证明了高脂肪饮食引起的糖耐量受损的肥胖小鼠血脑屏障通透性显着增加。肥胖时升高的TNF-α诱导周细胞源性MMP-9，导致血脑屏障功能障碍。因此，周细胞和周细胞MMP-9可能参与了血脑屏障功能障碍和肥胖的发展。

Brain pericytes are periendothelial accessory structures of the blood-brain barrier (BBB) and integral members of the neurovascular unit. Although neuron-glial cell interactions are essential for cerebral functions, an interaction between pericytes and neuron has still unknown. Our results suggested that pericytes would increase insulin sensitivity and decrease production of AgRP in hypothalamic neuron through soluble factors under physiological condition. On the other hand, we demonstrated that BBB permeability was significantly increased at obese mice with impaired glucose tolerance induced by high-fat diet. TNF-α, which is increased in obesity, induced pericyte-derived MMP-9, leading to BBB dysfunction. Therefore, pericytes and pericytal MMP-9 may be involved in BBB dysfunction in and development of obesity.