title: CaMKII regulates pericyte loss in the retina of early diabetic mouse.
abstract: Inducible nitric oxide synthase (iNOS) is an essential mediator in diabetic vascular lesions and known to be regulated by activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). The aim of this study was to investigate whether CaMKII affects iNOS-mediated pericyte death in the retina of diabetic mice with early stage disease. Total- and phospho-CaMKII, iNOS, and active caspase-3 protein levels were assessed by Western blotting, and CaMKII activity was measured by kinase assay. iNOS-related pericyte death was assessed by double immunofluorescent staining for iNOS and α-smooth muscle actin, followed by the TUNEL assay. Autocamtide-2-related inhibitory peptide (AIP), a specific inhibitor of CaMKII, was injected into the right vitreous 2 days before sacrifice of mice, to examine the effect of CaMKII inactivation in diabetic retinas. The levels of total- and phospho-CaMKII, iNOS, and active caspase-3 protein, and CaMKII activity were significantly increased in the diabetic retinas compared with those of control retinas. Furthermore, TUNEL-positive signals colocalized with iNOS-immunoreactive pericytes in the same retinas. However, inactivation of CaMKII by AIP treatment inhibited all these changes, which was accompanied by less pericyte loss. Our results demonstrate that CaMKII contributes to iNOS-related death of pericytes in the diabetic retina and that inactivation of this enzyme may be a potential treatment for retinal vascular lesion.
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, Brain Korea 21 Biomedical Center, Gyeongsang National University, Jinju, 660-751, Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Yoon Sook
authors.initials: YS
authors.lastname: Kim
authors.forename: So Yun
authors.initials: SY
authors.lastname: Park
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Park
authors.forename: Wan Sung
authors.initials: WS
authors.lastname: Choi
authors.forename: Gyeong Jae
authors.initials: GJ
authors.lastname: Cho
mesh_terms: D000818:Animals; D001813:Blood-Retinal Barrier / Q000187:drug effects / Q000473:pathology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology*; D004789:Enzyme Activation; D057075:Enzyme Assays; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D020286:Pericytes / Q000473:pathology*; D012160:Retina / Q000378:metabolism / Q000473:pathology*; D015854:Up-Regulation
chemical_list: D010455:Peptides; C514527:autocamptide-2-related inhibitory peptide II; D052247:Nitric Oxide Synthase Type II; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D053148:Caspase 3