1. Inhibition of mitochondrial complex II in neuronal cells triggers unique pathways culminating in autophagy with implications for neurodegeneration.
- Author
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Ranganayaki S, Jamshidi N, Aiyaz M, Rashmi SK, Gayathri N, Harsha PK, Padmanabhan B, and Srinivas Bharath MM
- Subjects
- 1-Methyl-4-phenylpyridinium pharmacology, Animals, Cell Death, Cell Line, Cell Survival, Cells, Cultured, Electron Transport Complex I antagonists & inhibitors, Electron Transport Complex I metabolism, Electron Transport Complex II antagonists & inhibitors, Gene Expression genetics, Gene Expression Profiling methods, Mitochondria metabolism, Movement Disorders physiopathology, Neurodegenerative Diseases metabolism, Neurodegenerative Diseases physiopathology, Neuroprotection, Neurotoxins toxicity, Nitro Compounds pharmacology, Propionates pharmacology, Rats, Transcriptome genetics, Autophagy physiology, Electron Transport Complex II metabolism, Neurons metabolism
- Abstract
Mitochondrial dysfunction and neurodegeneration underlie movement disorders such as Parkinson's disease, Huntington's disease and Manganism among others. As a corollary, inhibition of mitochondrial complex I (CI) and complex II (CII) by toxins 1-methyl-4-phenylpyridinium (MPP
+ ) and 3-nitropropionic acid (3-NPA) respectively, induced degenerative changes noted in such neurodegenerative diseases. We aimed to unravel the down-stream pathways associated with CII inhibition and compared with CI inhibition and the Manganese (Mn) neurotoxicity. Genome-wide transcriptomics of N27 neuronal cells exposed to 3-NPA, compared with MPP+ and Mn revealed varied transcriptomic profile. Along with mitochondrial and synaptic pathways, Autophagy was the predominant pathway differentially regulated in the 3-NPA model with implications for neuronal survival. This pathway was unique to 3-NPA, as substantiated by in silico modelling of the three toxins. Morphological and biochemical validation of autophagy markers in the cell model of 3-NPA revealed incomplete autophagy mediated by mechanistic Target of Rapamycin Complex 2 (mTORC2) pathway. Interestingly, Brain Derived Neurotrophic Factor (BDNF), which was elevated in the 3-NPA model could confer neuroprotection against 3-NPA. We propose that, different downstream events are activated upon neurotoxin-dependent CII inhibition compared to other neurotoxins, with implications for movement disorders and regulation of autophagy could potentially offer neuroprotection.- Published
- 2021
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