Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells.
Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders.
Department of Pharmacology, Hanyang University, Republic of Korea.
Jae Hyeon
JH
Park
Jeong Eun
JE
Lee
In Chul
IC
Shin
Hyun Chul
HC
Koh
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004390:Chlorpyrifos / Q000633:toxicity*; D006801:Humans; D007306:Insecticides / Q000633:toxicity*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D020258:Neurotoxicity Syndromes / Q000209:etiology / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D000071456:Sequestosome-1 Protein; D020123:Sirolimus / Q000494:pharmacology; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D007306:Insecticides; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; D051028:bcl-2-Associated X Protein; C025946:3-methyladenine; D053148:Caspase 3; D000225:Adenine; D004390:Chlorpyrifos; D020123:Sirolimus