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I. Suzuma, K. Suzuma, H. Takagi, Y. Honda; Cyclic Stretch induced Reactive Oxygen Species (ROS) Generation in Porcine Retinal Pericytes (PRPC) through PKC– Activation . Invest. Ophthalmol. Vis. Sci. 2004;45(13):3202.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Hypertension is well known to exacerbate diabetic retinopathy. Previously we reported that hypertension exacerbates diabetic retinopathy through not only augmenting VEGF–mediated neovascular system (Diabetes 50:444–454,2001) but also enhancement of pericyte apoptosis ROS–mediatedly (ARVO2003). Recent studies suggest ROS plays a crucial role in the pathogenesis of diabetic complications. The enhanced rennin–angiotensin–system(RAS) has been implicated to be involved in ROS generation in several cell systems. In this study, we investigated detailed mechanisms of stretch–induced ROS generation. Methods: PRPCs were exposed to cardiac–profile uniform radial cyclic stretch using a Flexcell apparatus. Production of ROS was measured with DCFH–DA. The activation of specific kinases were accessed by immunoblot analysis. Apoptosis was evaluated by DNA fragmentation and TUNEL methods. The role of PKC–δ was confirmed by overexpressing wild type (WT–) or dominant negative (DN–) mutants using adenovirus–mediated gene transfer. Results: Cyclic stretch (10%/60cpm) increased ROS generation (260%, p<0.01). Stretch–induced ROS generation was decreased by NAC, DPI, or rottlerin. Either AngiotensinII type 1 Receptor(AT1) or type 2 Receptor(AT2) blockade using specific inhibitors failed stretch–induced ROS generation. Stretch–induced PKC–δ activation increased association with p47phox subunit of NADPH Oxidase. PKC–δ depletion decreased caspase–3 activity by 75% (p<0.01) and rescued stretch–induced TUNEL positive cells (95%, p<0.01). Conclusions: These data indicates that cyclic stretch increases ROS generation through PKC–δ mediated NADPH Oxidase activation, suggesting that blood pressure control may have therapeuitic value for ameriolation of diabetic retinopathy progressionnone
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