Abstract 17073: Accumulation of P62 by Dysregulation of Autophagy Induces Rip1-dependent Necroptosis in Cardiomyocytes: a Novel Interplay Between Autophagy and Necroptosis

Background: Necroptosis, a recently recognized form of cell death, has been implicated in various pathological conditions including myocardial infarction. Activation of receptor-interacting protein kinase (RIP) 1, leading to RIP1-RIP3 complex formation, is a trigger event of necroptosis, but the mechanism for RIP1 activation has not been characterized fully. Objective: We examined the relationship between RIP1-dependent necroptosis and autophagy in cardiomyocytes. Methods: In H9c2 cardiomyoblasts, the necroptotic pathway was activated using TNF-α (TNF, 50 ng/ml) alone or co-incubation of TNF-α with 20 μM z-VAD-fmk, a pan-caspase inhibitor (TNF/zVAD). As an index of necrosis, the amount of LDH released into the culture medium 24 h after serum withdrawal was expressed as a percentage of total LDH. Necrostatin-1 (Nec-1, 20 μM) and cyclosporine A (CsA, 1 μM) were used for inhibiting RIP1-dependent necroptosis and mitochondrial permeability transition pore opening, respectively. Results: Treatment with TNF ind...