Abstract 18650: Ninjurin1, a Novel Regulatory Factor of Pericytes to Interact With Endothelial Cells, Mediates the Circulation Recovery in the Hind Limb Ischemia
Background: Microvascular maturation/stabilization is crucial phenomenon for patho-physiological situations such as ischemic diseases. Vascular maturation/stabilization is regulated through the interaction between pericytes (PCs) and endothelial cells (ECs). In order to clarify the mechanisms for vascular maturation/stabilization, we detected a novel factor, which is involved in the interaction between PCs and ECs using capillary-derived PCs cell lines, and examined the role of this factor on angiogenesis.
Methods and Results: We have established immortalized capillary-derived PCs from temperature sensitive SV40T-antigen-harboring mice. After GFP-expressing PCs were co-incubated with/without the sprouting EC tubes in 3D-gel, GFP-positive cells were collected by FACS and applied to microarray analysis. Ninjurin1 (nerve injured protein; Ninj1) have been selected among several candidate genes, of which expression levels in PCs were changed after interaction with sprouting EC tubes. When expression of Ninj1 in PCs was reduced by Ninj1-specific siRNA, the migration of PCs was enhanced. When Ninj1-reduced PCs was co-incubated with aorta ring in 3D-gel, the length of EC tubes sprouting from aorta ring was significantly increased compared to control PCs. Overexpression of Ninj1 in PCs affected the expression profile of angiogenic factors; potent ECs-growth factors such as VEGF and angiopoietin 1 (Ang1) were decreased, but Ang2 (vascular stabilizing factor) was increased. Expression of Ninj1 in PCs was enhanced by hypoxia culture condition in addition to the interaction with ECs. Expression of Ninj1 in ischemic skeletal muscle tissues was increased at 7~14 days after mouse hind limb ischemia operation. When the expression of Ninj1 was attenuated by the intra-muscular application of biodegradable hydrogel microbeads containing Ninj1-siRNA, the color-Doppler-assessed flow recovery in the ischemic hind limb was significantly reduced compared to the microbeads containing control siRNA.
Conclusion: Ninj1 regulates the EC-PC interactions and does not reduces mere EC-tubing formation, but adversely accelerates the maturation of microvessels, which may induce effective perfusion recovery in the ischemic tissues.
Author Disclosures: M. Matsuki: None. J. Kawabe: None. T. Aonuma: None. M. Kabara: None. A. Yamauchi: None. K. Shimamura: None. A. Minoshima: None. N. Takehara: None. Y. Saito: None. N. Hasebe: None.
- © 2014 by American Heart Association, Inc.