RGD Reference Report - 1-Methyl-4-phenylpyridinium-induced apoptosis in cerebellar granule neurons is mediated by transferrin receptor iron-dependent depletion of tetrahydrobiopterin and neuronal nitric-oxide synthase-derived superoxide. - Rat Genome Database

RGD Reference Report - 1-Methyl-4-phenylpyridinium-induced apoptosis in cerebellar granule neurons is mediated by transferrin receptor iron-dependent depletion of tetrahydrobiopterin and neuronal nitric-oxide synthase-derived superoxide. - Rat Genome Database

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1-Methyl-4-phenylpyridinium-induced apoptosis in cerebellar granule neurons is mediated by transferrin receptor iron-dependent depletion of tetrahydrobiopterin and neuronal nitric-oxide synthase-derived superoxide.
Authors:	Shang, Tiesong Kotamraju, Srigiridhar Kalivendi, Shasi V Hillard, Cecilia J Kalyanaraman, B
Citation:	Shang T, etal., J Biol Chem. 2004 Apr 30;279(18):19099-112. doi: 10.1074/jbc.M400101200. Epub 2004 Jan 29.
RGD ID:	13824992
Pubmed:	PMID:14752097 (View Abstract at PubMed)
DOI:	DOI:10.1074/jbc.M400101200 (Journal Full-text)
In this study, we investigated the molecular mechanisms of toxicity of 1-methyl-4-phenylpyridinium (MPP(+)), an ultimate toxic metabolite of a mitochondrial neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, that causes Parkinson-like symptoms in experimental animals and humans. We used rat cerebellar granule neurons as a model cell system for investigating MPP(+) toxicity. Results show that MPP(+) treatment resulted in the generation of reactive oxygen species from inhibition of complex I of the mitochondrial respiratory chain, and inactivation of aconitase. This, in turn, stimulated transferrin receptor (TfR)-dependent iron signaling via activation of the iron-regulatory protein/iron-responsive element interaction. MPP(+) caused a time-dependent depletion of tetrahydrobiopterin (BH(4)) that was mediated by H(2)O(2) and transferrin iron. Depletion of BH(4) decreased the active, dimeric form of neuronal nitric-oxide synthase (nNOS). MPP(+)-mediated "uncoupling" of nNOS decreased *NO and increased superoxide formation. Pretreatment of cells with sepiapterin to promote BH(4) biosynthesis or cell-permeable iron chelator and TfR antibody to prevent iron-catalyzed BH(4) decomposition inhibited MPP(+) cytotoxicity. Preincubation of cerebellar granule neurons with nNOS inhibitor exacerbated MPP(+)-induced iron uptake, BH(4) depletion, proteasomal inactivation, and apoptosis. We conclude that MPP(+)-dependent aconitase inactivation, Tf-iron uptake, and oxidant generation result in the depletion of intracellular BH(4), leading to the uncoupling of nNOS activity. This further exacerbates reactive oxygen species-mediated oxidative damage and apoptosis. Implications of these results in unraveling the molecular mechanisms of neurodegenerative diseases (Parkinson's and Alzheimer's disease) are discussed.

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Object Symbol	Species	Term	Qualifier	Evidence	With	Notes	Source	Original Reference(s)
Nos1	Rat	negative regulation of iron ion transmembrane transport		IMP			RGD
Nos1	Rat	negative regulation of neuron apoptotic process		IMP			RGD

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Genes (Rattus norvegicus)

Nos1 (nitric oxide synthase 1)

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