Monocrotophos Induced Apoptosis in PC12 Cells: Role of Xenobiotic Metabolizing Cytochrome P450s

Abstract

Monocrotophos (MCP) is a widely used organophosphate (OP) pesticide. We studied apoptotic changes and their correlation with expression of selected cytochrome P450s (CYPs) in PC12 cells exposed to MCP. A significant induction in reactive oxygen species (ROS) and decrease in glutathione (GSH) levels were observed in cells exposed to MCP. Following the exposure of PC12 cells to MCP (10−5 M), the levels of protein and mRNA expressions of caspase-3/9, Bax, Bcl2, P53, P21, GSTP1-1 were significantly upregulated, whereas the levels of Bclw, Mcl1 were downregulated. A significant induction in the expression of CYP1A1/1A2, 2B1/2B2, 2E1 was also observed in PC12 cells exposed to MCP (10−5 M), whereas induction of CYPs was insignificant in cells exposed to 10−6 M concentration of MCP. We believe that this is the first report showing altered expressions of selected CYPs in MCP-induced apoptosis in PC12 cells. These apoptotic changes were mitochondria mediated and regulated by caspase cascade. Our data confirm the involvement of specific CYPs in MCP-induced apoptosis in PC12 cells and also identifies possible cellular and molecular mechanisms of organophosphate pesticide-induced apoptosis in neuronal cells.

Induction of DNA base damage and strand breaks in peripheral erythrocytes and the underlying mechanism in goldfish (Carassius auratus) exposed to monocrotophos

“…Results of Kashyap et al (2011) indicated that Fish Physiol Biochem induced expression of CYPs might have up-regulated the production of ROS in cells after monocrotophos exposure. The antioxidant enzymes, on the other hand, play an important role in scavenging the overproduced ROS in tissues, but whether monocrotophos can interfere with the scavenging of ROS is still unknown.…”

“…Yu et al (2008) reported that chlorpyrifos increases the levels of DNA damage and lipid peroxidation and decreases activities of antioxidant enzymes superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) in the retina of mice, suggesting that inhibition of antioxidant enzyme activities may increase the level of ROS and further lead to the damage of DNA. Recently, Kashyap et al (2011) found that exposure of 10 -5 M monocrotophos increased the level of ROS in PC12 cells by elevating the mRNA expressions of CYP1A1/1A2, 2B1/2B2, 2E1 enzymes; however, whether the DNA damage induced by this pesticide is associated with alterations in the antioxidant system and accumulation of ROS is still equivocal. Therefore, to investigate the types of DNA damage induced by monocrotophos, different versions of the comet assay were applied in peripheral erythrocytes of goldfish (Carassius auratus) exposed to 0.01, 0.10, and 1.00 mg/L of this pesticide: The alkaline (pH [ 13), pH 12.1, and neutral (pH 8.2-8.5) comet assays were used to identify the global DNA damage (includes DSB, SSB, and ALS), DSB and SSB, and DSB, respectively; and the alkaline comet assay combined with endonuclease III (Endo III) or formamidopyrimidine DNA glycosylase (FPG) and with fluorescence in situ hybridization (FISH) was used to detect oxidative damage in DNA bases and telomeric DNA, respectively.…”

Placental Toxicology of Pesticides

“…Differential susceptibility to chlorpyrifos in these two cell lines may be explained, at least in part, by the fact that the transcription factor HNF1 (hepatic nuclear factor 1) is expressed ten times more in JAR than in JEG-3 cells , with this transcription factor playing an important role in CYP regulation. Although the involvement of CYPs in OP-induced apoptosis in neuronal cells has been previously reported (Kashyap et al, 2011), it is still not clear whether OP metabolism by CYPs and the induction of oxidative stress are implicated in trophoblast cell death.…”

Oxygen–Glucose Deprivation (OGD) Modulates the Unfolded Protein Response (UPR) and Inflicts Autophagy in a PC12 Hypoxia Cell Line Model

“…Apoptotic nuclei were assessed by fluorescence microscopy using the Zeiss Axioimager, and images were captured using the Isis software (Metasystems,Altlussheim, Germany). PC12 cells exposed to camptothecin at a concentration of 3 lg/ml (Sigma-Aldrich C-9911) for 6 h (Kashyap et al 2011) were used as a positive control.…”