cytochrome-c-t and perfluorooctane-sulfonic-acid

Perfluorinated chemicals (PFCs) are ubiquitously distributed in the environments including stainless pan-coating, raincoat, fire extinguisher, and semiconductor products. The PPAR family has been shown to contribute to the toxic effects of PFCs in thymus, immune and excretory systems. Herein, we demonstrated that perfluorooctanesulfonate (PFOS) caused cell apoptosis through increasing ratio of Bcl-xS/xL, cytosolic cytochrome C, and caspase 3 activation in renal tubular cells (RTCs). In addition, PFOS increased transcription of inflammatory cytokines (i.e., TNFα, ICAM1, and MCP1) by NFκB activation. Conversely, PFOS reduced the mRNA levels of antioxidative enzymes, such as glutathione peroxidase, catalase, and superoxide dismutase, as a result of reduced PPARγ transactivational activity by using reporter and chromatin immuoprecipitation (ChIP) assays. PFOS reduced the protein interaction between PPARγ and PPARγ coactivator-1 alpha (PGC1α) by PPARγ deacetylation through Sirt1 upregulation, of which the binding of PPARγ and PGC1α to a peroxisome proliferator response element (PPRE) in the promoter regions of these antioxidative enzymes was alleviated in the ChIP assay. Furthermore, Sirt1 also deacetylated p53 and then increased the binding of p53 to Bax, resulting in increased cytosolic cytochrome C. The effect of PPARγ inactivation by PFOS was validated using the PPARγ antagonist GW9662, whereas the adverse effects of PFOS were prevented by PPARγ overexpression and activators, rosiglitozone and L-carnitine, in RTCs. The in vitro finding of protective effect of L-carnitine was substantiated in vivo using Balb/c mice model subjected to PFOS challenge. Altogether, we provide in vivo and in vitro evidence for the protective mechanism of L-carnitine in eliminating PFOS-mediated renal injury, at least partially, through PPARγ activation.

Topics: Acetylation; Alkanesulfonic Acids; Animals; Antioxidants; Apoptosis; bcl-2-Associated X Protein; Carnitine; Cell Line; Cell Proliferation; Cytochromes c; Cytosol; Fluorocarbons; Genes, Reporter; Inflammation; Kidney Function Tests; Kidney Tubules; Male; Mice, Inbred BALB C; Oxidation-Reduction; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; PPAR gamma; Protective Agents; Protein Binding; Rats; Response Elements; Rosiglitazone; Signal Transduction; Sirtuin 1; Thiazolidinediones; Tumor Suppressor Protein p53

Perfluorooctanyl sulfonate (PFOS), a cardiac toxicity compound, has been widely detected in the environment and in organisms. However, the toxic mechanism is not clear. Our previous study indicated that prenatal PFOS exposure led to swollen mitochondrial with vacuolar structure and loss of cristae in offsping's heart. The purpose of this study was to investigate the effect of PFOS on the apoptosis in developing heart and mitochondria-mediated apoptosis pathway. Pregnant Sprague-Dawley (SD) rats were exposed to PFOS at doses of 0.1, 0.6, and 2.0 mg/kg-d and 0.05% Tween 80 as control by gavage from gestation day 2 (GD 2) to GD 21. Apoptosis, as well as expression of apoptosis related genes associated with mitochondrial-mediated apoptosis pathway, including p53, bcl-2, bax, cytochrome c, caspase-9, and caspase-3 were analyzed in heart tissues from weaned (postnatal day 21, PND 21) offspring. The results showed that prenatal PFOS exposure resulted in apoptosis in the offspring's heart. The mRNA and protein expression levels of p53, bax, cytochrome c, caspase-9, and caspase-3 in the offspring's heart were enhanced in various PFOS-treated groups, meanwhile, the bcl-2 expression levels were decreased. Our results indicated that prenatal PFOS exposure induced the apoptosis of weaned offspring rat heart tissue via mitochondria-mediated apoptotic pathway.

Topics: Alkanesulfonic Acids; Animals; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cytochromes c; Female; Fluorocarbons; Heart; Male; Mitochondria; Myocardium; Pregnancy; Prenatal Exposure Delayed Effects; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tumor Suppressor Protein p53; Weaning

Perfluorooctane sulfonate (PFOS) could induce neonatal pulmonary injuries in rodents. The aim of this study was to investigate the underlying mode of action. Pregnant rats were dosed orally with PFOS (0, 0.1 and 2.0mg/kgd) from gestation days (GD) 1 to 21. Lung samples from postnatal day (PND) 0 and 21 pups were analyzed for the toxic effects of PFOS. The results showed that maternal exposure to 2.0mg/kgd PFOS caused severe histopathological changes along with marked oxidative injuries and cell apoptosis in offspring lungs; at the same time, the ratio of Bax to Bcl-2, release of cytochrome c (Cyt c) from mitochondria to cytoplasm, expressions of Fas and Fas-L, and activities of caspase-3, -8 and -9 were up-regulated correspondingly. The results indicate that oxidative stress and both intrinsic and extrinsic cell death pathways were involved in prenatal PFOS exposure-induced injuries in postnatal lungs.

Topics: Alkanesulfonic Acids; Animals; Apoptosis; Blotting, Western; Cytochromes c; Cytosol; Environmental Pollutants; Female; Fluorocarbons; Gene Expression; Gestational Age; In Situ Nick-End Labeling; Lung; Maternal Exposure; Oxidative Stress; Pregnancy; Prenatal Exposure Delayed Effects; Protein Transport; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction

Perfluorooctane sulfonate (PFOS) is a persistent environmental contaminant found in human and wildlife tissues. It has been reported that PFOS can cause atrophy of the immune organs and apoptosis of immunocytes in rodents. However, the mechanism behind such cause is still unclear. To understand the model of cell death and its mechanism on lymphoid cells in vivo, we conducted a dose/response experiment in which 4 groups of male adult C57BL/6 mice (12 mice per group) were dosed daily by oral gavage with PFOS at 0, 0.0167, 0.0833, or 0.8333mg/kg/day, yielding targeted Total Administered Dose (TAD) of 0, 1, 5, or 50mg PFOS/kg, respectively, over 60days. The results showed that spleen and thymus weight were significantly reduced in the highest PFOS-dose-group (TAD 50mg PFOS/kg) compared to the control group, whereas liver weight was significantly increased. We analyzed the cell death via apoptosis with an annexin-V/propidium iodide assay by flow cytometry, and observed that both the percentage of apoptosis and the expression of the pro-apoptotic proteins p53 in splenocytes and thymocytes increased in a dose-related manner after PFOS treatment. We also observed that PFOS induced p53-dependent apoptosis through the cooperation between the Bcl-xl down regulation without changing the Bcl-2 and Bax expression. The down regulation of Bcl-xl was strongly indicating mitochondrial involvement in apoptosis. It is confirmed by the release of cytochrome c and activation of caspase-3. All of these findings establish an important role of p53 and mitochondrial function in PFOS induced toxic environment in the host.

Topics: Alkanesulfonic Acids; Animals; Apoptosis; Apoptosis Inducing Factor; bcl-2-Associated X Protein; bcl-X Protein; Caspase 3; Cell Count; Cell Cycle; Cell Separation; Cell Survival; Cytochromes c; Flow Cytometry; Fluorocarbons; Immunosuppressive Agents; Male; Membrane Potential, Mitochondrial; Mice; Mice, Inbred C57BL; Necrosis; Organ Size; Spleen; Thymocytes; Tumor Suppressor Protein p53