The ATPase Inhibitory Factor 1 (IF1) is an inhibitor of the mitochondrial H+-ATP synthase that regulates the activity of both oxidative phosphorylation (OXPHOS) and cell death. Here, we have developed transgenic Tet-On and Tet-Off mice that express a mutant active form of hIF1 in the hepatocytes to restrain OXPHOS in the liver to investigate the relevance of mitochondrial activity in hepatocarcinogenesis. The expression of hIF1 promotes the inhibition of OXPHOS in both Tet-On and Tet-Off mouse models and induces a state of metabolic preconditioning guided by the activation of the stress kinases AMPK and p38 MAPK. Expression of the transgene significantly augmented proliferation and apoptotic resistance of carcinoma cells, which contributed to an enhanced diethylnitrosamine-induced liver carcinogenesis. Moreover, the expression of hIF1 also diminished acetaminophen-induced apoptosis, which is unrelated to differences in permeability transition pore opening. Mechanistically, cell survival in hIF1-preconditioned hepatocytes results from a nuclear factor-erythroid 2-related factor (Nrf2)-guided antioxidant response. The results emphasize in vivo that a metabolic phenotype with a restrained OXPHOS in the liver is prone to the development of cancer.
SIRT1 protein levels are downregulated by IL1β/NFκB signaling in APAP hepatotoxicity, resulting in inflammation and oxidative stress. Thus, maintenance of SIRT1 during APAP overdose by inhibiting NFκB might be clinically relevant. Rebound Track: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16:293-296, 2012) with the following serving as open reviewers: Rafael de Cabo, Joaquim Ros, Kalervo Hiltunen, and Neil Kaplowitz. Antioxid. Redox Signal. 28, 1187-1208.
Acute hepatic failure secondary to acetaminophen (APAP) poisoning is associated with high mortality. Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of tyrosine kinase growth factor signaling. In the liver, this pathway confers protection against injury. However, the involvement of PTP1B in the intracellular networks activated by APAP is unknown. We have assessed PTP1B expression in APAP-induced liver failure in humans and its role in the molecular mechanisms that regulate the balance between cell death and survival in human and mouse hepatocytes, as well as in a mouse model of APAP-induced hepatotoxicity. PTP1B expression was increased in human liver tissue removed during liver transplant from patients for APAP overdose. PTP1B was upregulated by APAP in primary human and mouse hepatocytes together with the activation of c-jun (NH2) terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), resulting in cell death. Conversely, Akt phosphorylation and the antiapoptotic Bcl2 family members BclxL and Mcl1 were decreased. PTP1B deficiency in mouse protects hepatocytes against APAP-induced cell death, preventing glutathione depletion, reactive oxygen species (ROS) generation and activation of JNK and p38 MAPK. APAP-treated PTP1B−/− hepatocytes showed enhanced antioxidant defense through the glycogen synthase kinase 3 (GSK3)β/Src kinase family (SKF) axis, delaying tyrosine phosphorylation of the transcription factor nuclear factor-erythroid 2-related factor (Nrf2) and its nuclear exclusion, ubiquitination and degradation. Insulin-like growth factor-I receptor-mediated signaling decreased in APAP-treated wild-type hepatocytes, but was maintained in PTP1B−/− cells or in wild-type hepatocytes with reduced PTP1B levels by RNA interference. Likewise, both signaling cascades were modulated in mice, resulting in less severe APAP hepatotoxicity in PTP1B−/− mice. Our results demonstrated that PTP1B is a central player of the mechanisms triggered by APAP in hepatotoxicity, suggesting a novel therapeutic target against APAP-induced liver failure.
Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial proliferation and bone destruction. Adenosine deaminase (ADA) is a key inflammatory enzyme that increases joint stiffness and pain in RA. In this study, we evaluated the in-silico, and in vivo inhibitory effect of quercetin isolated from Egyptian Fenugreek on ADA enzyme activity. We also determined the combinatorial effect of quercetin on methotrexate mediated anti-inflammatory efficacy and toxicity. In-silico molecular docking was conducted and confirmed in an in vivo RA rat model. The results showed that the inhibition constant of quercetin on joint ADA by docking and in-vitro was 61.9 and 55.5 mM, respectively. Therefore, quercetin exhibits anti-inflammatory effect in a rat RA model as evidenced by reducing the specific activity of ADA in joint tissues, lower jaw volume, enhance body weight, downregulate ADA gene expression, reduce levels of RA cytokines interleukin-1β, interleukin-6, tumor necrosis factor-α, also, rheumatoid factor, C-reactive protein, and anti-cyclic citrullinated peptide RA biomarker levels. These findings demonstrate that the purified quercetin has a promising anti-inflammatory effect against RA disease through its inhibitory effects on the ADA enzyme. Furthermore, isolated quercetin improved the anti-inflammatory efficacy of methotrexate, reduced its toxic effects by increasing antioxidant enzymes and reducing oxidative stress.
In a recent study, the treatment of different human cancer cell lines in vitro with ethylene diamine tetra-acetic acid (EDTA) showed a promising anticancer activity which could be a novel promising approach for cancer treatment. The aim of this study is to address the ability of EDTA to enhance the antitumor efficacy of the low dose of cisplatin (Cis) treatment in Ehrlich ascetic carcinoma (EAC) bearing mice. Sixty female albino mice were divided into six groups. The 1 st group of mice was served as a negative control. 2 nd -6 th groups were inoculated intraperitoneal (i.p) with 2×10 6 EAC cells/mouse. After one day of inoculation, the 2 nd , 3 rd and 4 th groups were injected daily for 6 days (early treatment) with phosphate buffer saline, low dose of Cis and Cis/EDTA, respectively. After six days, the 5 th and 6 th groups were injected with the low dose of Cis and Cis/EDTA for 6 consecutive days (late treatment), respectively. At day 14, all groups of mice were sacrificed, sera were collected for biochemical assessment, HIGHLIGHTS• EDTA enhanced the antitumor efficacy of the low dose of Cisplatin.• Low dose of Cisplatin did not inhibit tumor growth • Co-treatment with EDTA delayed and decreased tumor growth.• EDTA decreased the toxicity of Cisplatin. 2 El-Naggar, S.A.; et al.
Background: Several studies have found an association between Diabetes mellitus (DM) and an increased risk for hepatocellular carcinoma (HCC). Evidence suggests that Metformin (Met) may have a therapeutic and protective effect against both DM and HCC. Therefore, the aim of this study was to evaluate the antioxidant effect of Met against DM and HCC-induced oxidative stress in rat model. Methods: Forty-two male albino rats were randomly divided into six groups. Group 1 (Gp1) was the control group, Gp2 received an intraperitoneal (i.p.) injection with streptozotocin (STZ), Gp3 was injected i.p. with diethyl nitrosamine (DEN), Gp4 received an oral administration of Met, Gp5 and Gp6 received the same injections as Gp2 and Gp3, respectively, then received an additional injection of Met. Oxidative stress biomarkers, including superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and malondialdehyde (MDA), were examined. Furthermore, biochemical parameters including liver function tests were assessed. Histopathological and immunohistochemical alterations of the liver were also examined. Results: Our results demonstrate that Gp2 and Gp3 had significant signs of liver dysfunction and had elevated levels of MDA and reduced levels of SOD, CAT, and GSH. Additionally, Gp2 and Gp3 showed significant alterations in the liver architecture shown by high PCNA and caspase-3 expression. In the Gp5 and Gp6, treatment with Met showed an improvement in liver function, oxidative stress biomarkers, and reduced histopathological changes in hepatocytes. Conclusions: This study offers insight into the potential for Metformin as a novel therapeutic against the oxidative stress induced by DM or HCC.
Background: PTP1B is a negative modulator of insulin receptor-mediated signaling. Results: Acetaminophen increased PTP1B in hepatocytes and impaired insulin signaling. Conclusion: PTP1B plays an essential role in the impairment of insulin signaling mediated by acetaminophen in hepatocytes. Significance: Chronic acetaminophen administration might be associated with insulin resistance in the liver.
The possible renal and hepatic toxicities of ethylenediaminetetraacetic acid (EDTA) in bean cooking media were studied using 100 male albino mice. Two sublethal doses of EDTA were used to explore their toxic effects; 20 mg/kg and 200 mg/kg, which corresponded to 1/100th and 1/10th of LD50, respectively. Accordingly, the toxicity study was performed using 50 mice, divided into five groups ( n = 10/group) as follows: group 1 (Gp1) served as a negative control and was orally administered normal saline; group 2 (Gp2) was administered the bean cooking medium; group 3 (Gp3) was administered EDTA (200 mg/kg); group 4 (Gp4) was administered bean cooking medium containing 20 mg/kg of EDTA; and group 5 (Gp5) was administered bean cooking medium containing 200 mg/kg of EDTA. The results showed no significant changes in liver and kidney functions in Gp2 while Gp3, Gp4, and Gp5 exhibited significant increases in adverse liver and kidney function markers. Hematocrit values were significantly decreased in Gp3 and Gp5, while the total white blood cells counts were significantly decreased in Gp3 and significantly increased in Gp5. The number of platelets was decreased in Gp3, Gp4, and Gp5. The blood levels of sodium (Na+), iron (Fe2+), and calcium (Ca2+) were decreased in Gp3, Gp4, and Gp5 due to the chelating effects of EDTA. The hepatic and renal architectures were disorganized in Gp3, Gp4, and Gp5 with some hemorrhagic manifestations in livers and kidneys of mice. These results demonstrate that EDTA in bean cooking is harmful in mice under the conditions of this study, and the potentially harmful effects in humans supports restricting its use.
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