sirolimus and decamethrin

The autophagy pathway can be induced and upregulated in response to intracellular reactive oxygen species (ROS). In this study, we explored a novel pharmacotherapeutic approach involving the regulation of autophagy to prevent deltamethrin (DLM) neurotoxicity. We found that DLM-induced apoptosis in PC12 cells, as demonstrated by the activation of caspase-3 and -9 and by nuclear condensation. DLM treatment significantly decreased dopamine (DA) levels in PC12 cells. In addition, we observed that cells treated with DLM underwent autophagic cell death, by monitoring the expression of LC3-II, p62, and Beclin-1. Exposure of PC12 cells to DLM led to the production of ROS. Treatment with N-acetyl cysteine (NAC) effectively blocked both apoptosis and autophagy. In addition, mitogen-activated protein kinase (MAPK) inhibitors attenuated apoptosis as well as autophagic cell death. We also investigated the modulation of DLM-induced apoptosis in response to autophagy regulation. Pretreatment with the autophagy inducer, rapamycin, significantly enhanced the viability of DLM-exposed cells, and this enhancement of cell viability was partially due to alleviation of DLM-induced apoptosis via a decrease in levels of cleaved caspase-3. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), significantly increased DLM toxicity in these cells. Our results suggest that DLM-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against DLM-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 109-121, 2017.

Topics: Animals; Anti-Bacterial Agents; Apoptosis; Autophagy; Cell Survival; Dopamine; Humans; Insecticides; Nitriles; PC12 Cells; Pyrethrins; Rats; Reactive Oxygen Species; Sirolimus; TOR Serine-Threonine Kinases

The present study was undertaken to examine the physical and physiological interaction of protein phosphatase 2B, calcineurin, with the ryanodine receptor (RyR) in rat cardiac tissue and neonatal cardiomyocytes. The presence of calcineurin, the RyR and FK506-binding protein (FKBP)12.6 in rat cardiac sarcoplasmic reticulum (SR) was identified by Western blot analysis. The possible interactions between calcineurin, the RyR and FKBP12.6 were further studied by co-immunoprecipitation using CHAPS-solubilized cardiac-membrane fractions (CSMFs) or SR preparations. Physical interactions between the RyR and calcineurin were found in the CSMF in the presence of added 100 microM Ca(2+); however, the interactions were interrupted in the presence of 20 mM EGTA, 1 microM rapamycin or 1 microM FK506, suggesting that the interaction is Ca(2+)-dependent, and is mediated by FKBP12.6. The Ca(2+)-dependent interaction between FKBP12.6 and the RyR was also found by co-immunoprecipitation. Effects of calcineurin inhibitors were tested on neonatal-rat-heart cardiomyocytes. Treatment of neonatal cardiomyocytes with 20 microM deltamethrin, 10 microM cyclosporin A (CsA), or 10 mciroM FK506 led to Ca(2+) oscillations in originally quiescent cardiomyocytes. Preincubation of cardiomyocytes with 20 microM rapamycin which dissociates FKBP12.6 from the RyR, evoked Ca(2+) oscillations, probably due to the leakiness of the RyR. However, Ca(2+) oscillations by rapamycin were not further affected by 10 microM CsA or 10 mciroM deltamethrin, suggesting that only RyR-associated calcineurin could regulate the channel activities. In spontaneously Ca(2+)-oscillating cardiomyocytes, CsA or FK506 treatments increased the frequency of oscillations. In 10 microM ryanodine-treated cardiomyocytes, CsA failed to induce Ca(2+) oscillations. These data show evidence that calcineurin associated with the RyR could modulate Ca(2+) release in rat heart.

Topics: Animals; Animals, Newborn; Blotting, Western; Calcineurin; Calcium; Calcium Channels; Cells, Cultured; Chelating Agents; Cholic Acids; Cyclosporine; Detergents; Egtazic Acid; Fluorescent Antibody Technique; Immunosuppressive Agents; Insecticides; Microscopy, Confocal; Myocardium; Nitriles; Phosphorylation; Precipitin Tests; Protein Binding; Pyrethrins; Rats; Rats, Sprague-Dawley; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Sirolimus; Tacrolimus; Tacrolimus Binding Proteins; Time Factors