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pubmed:abstractText |
Autophagy, a major degradation process for long-lived and aggregate-prone proteins, affects various human processes, such as development, immunity, cancer, and neurodegeneration. Several autophagy regulators have been identified in recent years. Here we show that nitric oxide (NO), a potent cellular messenger, inhibits autophagosome synthesis via a number of mechanisms. NO impairs autophagy by inhibiting the activity of S-nitrosylation substrates, JNK1 and IKK?. Inhibition of JNK1 by NO reduces Bcl-2 phosphorylation and increases the Bcl-2-Beclin 1 interaction, thereby disrupting hVps34/Beclin 1 complex formation. Additionally, NO inhibits IKK? and reduces AMPK phosphorylation, leading to mTORC1 activation via TSC2. Overexpression of nNOS, iNOS, or eNOS impairs autophagosome formation primarily via the JNK1-Bcl-2 pathway. Conversely, NOS inhibition enhances the clearance of autophagic substrates and reduces neurodegeneration in models of Huntington's disease. Our data suggest that nitrosative stress-mediated protein aggregation in neurodegenerative diseases may be, in part, due to autophagy inhibition.
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pubmed:affiliation |
Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0XY, UK.
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