title: Inhibition of PKR impairs angiogenesis through a VEGF pathway.
abstract: Peripheral artery disease (PAD) is a common clinical problem, and its pathophysiological mechanisms are incompletely understood. Double-stranded RNA-activated protein kinase (PKR) is a ubiquitously expressed serine/threonine protein kinase. Although PKR has been reported in antivirus and the immune system, the role of PKR in vascular function, especially in angiogenesis, is still unclear. PKR(-/-) mice were used in our experiments. Blood flow recovery was significantly delayed in PKR(-/-) vs. WT mice (Laser Doppler detection, n = 9, P < 0.01), accompanied by 34% reduced CD31-positive stain in ischemic muscle 28 days after procedure (immunohistochemistry, n = 9, P < 0.05). PKR expression decreased in the first 12 h and increased to peak at 24 h in human umbilical vein endothelial cells (HUVECs) in response to hypoxia (Western blot analyses, n = 3, P < 0.05). Accordingly, phospho-PKR expression increased in HUVECs 24 h after treatment with hypoxia (Western blot analyses, n = 3, P < 0.05). Inhibition of PKR (siRNA transfection) reduced microtubule formation (Matrigel tube formation, n = 3, vs. control siRNA, P < 0.05) and migration (wound healing, n = 3, vs. control siRNA, P < 0.05) by 33 and 59%, respectively. Vascular endothelial growth factor (VEGF) expression in ischemic muscle from PKR(-/-) mice was significantly decreased by 54% 1 day after procedure (n = 3, P < 0.05, vs. WT) and by 63% 7 days after procedure (n = 3, P < 0.01, vs. WT), respectively. At the same time, VEGF expression in HUVECs decreased by 21% (n = 3, P < 0.05, PKR siRNA vs. control siRNA). These findings demonstrate that PKR mediates angiogenesis through a VEGF pathway, which may form the basis for future intervention of PAD.
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Zhaowei
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: The Third Xiangya Hospital and the College of Pharmacy, Central South University, Changsha, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Xinqun
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Dandan
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Jiemei
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Jinze
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Cai
authors.affiliation: The Third Xiangya Hospital and the College of Pharmacy, Central South University, Changsha, China.
authors.forename: Shenghua
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, China; and afychen@yahoo.com.
authors.forename: Alex F
authors.initials: AF
authors.lastname: Chen
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000235:genetics*; D058729:Peripheral Arterial Disease / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*; D019892:eIF-2 Kinase / Q000037:antagonists & inhibitors / Q000235:genetics*
chemical_list: D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D019892:eIF-2 Kinase
keywords: angiogenesis; double-stranded RNA-activated protein kinase; peripheral artery disease; vascular endothelial cell growth factor