Infection of human brain vascular pericytes (HBVPs) by Bartonella henselae

Angiogenesis is an important physiological and pathological process. Bartonella is the only genus of bacteria known to induce pathological angiogenesis in the mammalian host. Bartonella-induced angiogenesis leads to the formation of vascular tumors including verruga peruana and bacillary angiomatosis. The mechanism of Bartonella-induced angiogenesis is not completely understood. Pericytes, along with endothelial cells, play an important role in physiological angiogenesis, and their role in tumor angiogenesis has been extensively studied. Abnormal signaling between endothelial cells and pericytes contributes to tumor angiogenesis and metastasis; however, the role of pericytes in Bartonella-induced angiogenesis is not known. In this study, after infecting human brain vascular pericytes (HBVPs) with Bartonella henselae, we found that these bacteria were able to invade HBVPs and that bacterial infection resulted in decreased pericyte proliferation and increased pericyte production of vascular endothelial growth factor (VEGF) when compared to the uninfected control cells. In the context of pathological angiogenesis, reduced pericyte coverage, accompanied by increased VEGF production, may promote endothelial cell proliferation and the formation of new vessels.