Effects Of Interaction Between Moesin And CD44 On Pericyte Loss And Immature Neovessel Formation In Diabetes

BackgroundRetinopathy,a serious microvascular complication of diabetes,is the leading cause of new cases of blindness in adults.The pathology develops in two different stages:non-proliferative diabetic retinopathy(NPDR)and proliferative diabetic retinopathy(PDR).Persistent,uncontrolled formation of premature blood vessels is a key pathological characteristic of PDR.Neovessels covered with enough numbers of pericytes is a hallmark of vessel maturation.Pericyte loss is the classic histologic lesion in early diabetic retinopathy,which might be a result of migration.We previously demonstrated that advanced glycation endproducts(AGEs)promoted human umbilical vein endothelial cells(HUVECs)angiogenesis by inducing moesin phosphorylation.ObjectiveTo investigate the effects and possible mechanism of interaction between CD44 and phospho-moesin on AGE-induced RMPs(retinal microvascular pericyte,RMP),migration and neovessle maturation.MethodsAGE-treated mouse model was developed in WT mice by intraperitoneal injection of AGE-BSA.The coverage of pericyte in retinal capillary vessel was observed by immunofluorescence staining NG2 in CLSM.Primary RMPs were isolated,purified from weanling rats,and identified by cellular markers ?-SMA,PDGFR-?,NG2 and desmin using immunofluorescence microscopy.Cell proliferation and migration were induced in different concentration of AGE-BSA and indicated time detected by CCK-8,wound heal and transwell assy.The effects of activating and inhibiting mutant of moesin phosphorylation of Thr 558,or ROCK inhibitor Y27632 on AGE-induced RMP loss were also detected.The expression of phospho-moesin was measured using western blotting.Colocalization and interaction between CD44,phospho-moesin and F-actin was detected by confocal laser scanning microscopy(CLSM)and co-immunoprecipitation.ResultsAGE-BSA decreased cell proliferation,while increased moesin phosphorylation,which was in consistent with RMP migration accumulation in a dose-and time-dependent manner.Similarly,AGE-BSA induced RMPs loss in retinal capillary in WT mice after 6 months' treatment.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 mimicked AGE-induced cell migration and F-actin alteration.The inhibition of ROCK inhibitor Y27632 decreased AGE-induced moesin phosphorylation and subsequently attenuated pericyte migration.AGE-BSA promoted CD44 and phospho-moesin interaction and redistribution of altered F-actin in RMPs,which can be suppressed by Y27632.ConclusionThe interaction of phospho-moesin and CD44 was induced by AGE-BSA,which mediating moesin phosphorylation at T558 site through ROCK activation,leading to RMPs migration and loss.It might provide a new target for immature neovessel formation in diabetes.