Interaction of Phospho‐Moesin and CD44 in Pericytes Attenuated the Maturation of Neovessles in AGE‐induced Angiogenesis

Abstract

BackgroundWe have previously demonstrated that advanced glycation endproducts (AGEs) promoted angiogenesis by inducing ERM phosphorylation, especially, moesin phosphorylation in human umbilical vein endothelial cells (HUVECs). This study was to investigate the effect of moesin phosphorylation on angiogenesis and neovessel maturation in aortic ring and retina in AGE‐treated mice. This study also focus on the impact of interaction between phospho‐moesin and CD44 on AGE‐induced retinal microvascular pericyte (RMP) migration and neovessel maturation.MethodsAGE‐treated mouse model was developed in WT mice, in receptor for AGEs (RAGE)‐knockout (RAGE(−/−)) mice and in WT postnatal mice by intraperitoneal injection of AGEs. retinal vessels were observed by whole mount immunofluorescence staining for isolectin B4 (IB4). Mouse aorta rings were embedded in 3D collagen and the sprouted vascular endothelial cells was identified by immunofluorescent staining IB4. Pericytes were identified with NG2 or α‐SMA in retina and aortic ring. Primary RMPs were isolated, purified from weanling rats, and identified by cellular markers α‐SMA, PDGFR‐β, NG2 and desmin using immunofluorescence microscopy. Migration of RMPs was induced in different condition and detected with transwell. The phosphorylation of moesin was measured using western blotting. Colocalization and interaction between CD44, phospho‐moesin and F‐actin was detected by confocal laser scanning microscopy and coimmunoprecipitation.ResultsThe number of neovessels in retina and the phosphorylation of moesin were increased in WT mice after AGE treatment for 1, 2, and 6 months, and the increase of retinal neovessels was more obvious with time extension. There were no significant alteration in RAGE(−/−) mice after AGE treatment for six months. The phosphorylation of moesin and the number of neovessels in retina were increased in WT postnatal mice after AGE treatment for 7 d. Both in vivo and in vitro AGE treatment could enhanced the phosphorylation of moesin and promoted neovessel sprouting in mouse aortic ring, while there were not significant changes in RAGE(−/−) mouse aortic ring. The pericyte cover rate was reduced in neovessels in AGE‐treated mouse aortic ring, as well as in retinal microvessels in AGE‐treated mice. AGE‐BSA increased moesin phosphorylation in RMPs, which was in consistent with RMP migration in a dose‐ and time‐dependent manner. AGE‐BSA promoted CD44 and phospho‐moesin interaction, as well as the F‐actin stress fiber reassembly. The inhibition of ROCK by specific inhibitor Y27632 decreased AGE‐induced moesin phosphorylation and subsequently attenuated pericyte migration, suppressed the formation of CD44‐phospho‐ERM complex and redistribution of F‐actin. The inhibiting mutant of phosphorylation of Thr 558 in moesin suppressed AGE‐induced migration and F‐actin rearrangement, while the activating mutant of moesin phosphorylation of Thr 558 promoted cell migration and F‐actin alteration.ConclusionsAGEs promoted angiogenesis in mice by inducing moesin phosphorylation. The interaction of phospho‐moesin and CD44 participates in the pathogenesis of AGE‐induced RMP migration through ROCK activation and might hamper the maturation of neovessels.Support or Funding InformationSponsored by General Program from Natural Science Foundation of China (81370226, 81170297, and 80971201)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.