title: TRPC1-mediated inhibition of 1-methyl-4-phenylpyridinium ion neurotoxicity in human SH-SY5Y neuroblastoma cells.
abstract: Mammalian homologues of the Drosophila canonical transient receptor potential (TRP) proteins have been implicated to function as plasma membrane Ca(2+) channels. This study examined the role of TRPC1 in human neuroblastoma (SH-SY5Y) cells. SH-SY5Y cells treated with an exogenous neurotoxin, 1-methyl-4-phenylpyridinium ion (MPP(+)) significantly decreased TRPC1 protein levels. Confocal microscopy on SH-SY5Y cells treatment with MPP(+) showed decreased plasma membrane staining of TRPC1. Importantly, overexpression of TRPC1 reduced neurotoxicity induced by MPP(+). MPP(+)-induced alpha-synuclein expression was also suppressed by TRPC1 overexpression. Protection of SH-SY5Y cells against MPP(+) was significantly decreased upon the overexpression of antisense TRPC1 cDNA construct or the addition of a nonspecific transient receptor potential channel blocker lanthanum. Activation of TRPC1 by thapsigargin or carbachol decreased MPP(+) neurotoxicity, which was partially dependent on external Ca(2+). Staining of SH-SY5Y cells with an apoptotic marker (YO-PRO-1) showed that TRPC1 protects SH-SY5Y neuronal cells against apoptosis. Further, TRPC1 overexpression inhibited cytochrome c release and decreased Bax and Apaf-1 protein levels. Interpretation of the above data suggests that reduction in the cell surface expression of TRPC1 following MPP(+) treatment may be involved in dopaminergic neurodegeneration. Furthermore, TRPC1 may inhibit degenerative apoptotic signaling to provide neuroprotection against Parkinson's disease-inducing agents.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203, USA.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Bollimuntha
authors.forename: Brij B
authors.initials: BB
authors.lastname: Singh
authors.forename: Shaik
authors.initials: S
authors.lastname: Shavali
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Manuchair
authors.initials: M
authors.lastname: Ebadi
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D015220:Calcium Channels / Q000502:physiology*; D045744:Cell Line, Tumor; D017931:DNA Primers; D006801:Humans; D018613:Microscopy, Confocal; D009447:Neuroblastoma / Q000473:pathology*; D050052:TRPC Cation Channels
chemical_list: D015220:Calcium Channels; D017931:DNA Primers; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D015655:1-Methyl-4-phenylpyridinium