According to numerous animal studies, adverse environmental stimuli, including physical, chemical, and biological factors, can cause low‐grade chronic inflammation and subsequent tumor development. Human epidemiological evidence has confirmed the close relationship between chronic inflammation and tumorigenesis. However, the mechanisms driving the development of persistent inflammation toward tumorigenesis remain unclear. In this study, we assess the potential role of reactive oxygen species (ROS) and associated mechanisms in modulating inflammation‐induced tumorigenesis. Recent reports have emphasized the cross‐talk between oxidative stress and inflammation in many pathological processes. Exposure to carcinogenic environmental hazards may lead to oxidative damage, which further stimulates the infiltration of various types of inflammatory cells. In turn, increased cytokine and chemokine release from inflammatory cells promotes ROS production in chronic lesions, even in the absence of hazardous stimuli. Moreover, ROS not only cause DNA damage but also participate in cell proliferation, differentiation, and apoptosis by modulating several transcription factors and signaling pathways. We summarize how changes in the redox state can trigger the development of chronic inflammatory lesions into tumors. Generally, cancer cells require an appropriate inflammatory microenvironment to support their growth, spread, and metastasis, and ROS may provide the necessary catalyst for inflammation‐driven cancer. In conclusion, ROS bridge the gap between chronic inflammation and tumor development; therefore, targeting ROS and inflammation represents a new avenue for the prevention and treatment of cancer.
20 March 2023 in Free Radical Biology and Medicine
Mitochondrial dysfunction and oxidative stress are considered to be key events in acetaminophen (APAP)-induced acute liver injury. Mitochondrial quality control, including mitophagy and mitochondrial synthesis, can restore mitochondrial homeostasis and thus protect the liver. The role of PARK7, a mitochondrial stress protein, in regulating mitochondrial quality control in APAP-induced hepatotoxicity is unclear. In this study, L02 cells, AML12 cells and C57/BL6 mice were each used to establish models of APAP-induced acute liver injury. PARK7 was silenced in vitro by lentiviral transfection and knocked down in vivo by AAV adeno-associated virus. Changes in cell viability, apoptosis, reactive oxygen species (ROS) level, serum enzyme activity and pathological features were evaluated after APAP treatment. Western blotting, real-time PCR, immunofluorescence, electron microscopy and Seahorse assays were used to detect changes in key indicators of mitochondrial quality control. The results showed that APAP treatment decreased cell viability and increased the apoptosis rate, ROS levels, serum enzyme activity, pathological damage and PARK7 expression. PARK7 silencing or knockdown ameliorated APAP-induced damage to the cells and liver. Furthermore, PARK7 silencing enhanced mitophagy, increased mitochondrial synthesis, and led to a switch from oxidative phosphorylation to glycolysis. Taken together, these results suggest that PARK7 is involved in APAP-induced acute liver injury by regulating mitochondrial quality control and metabolic reprogramming. Therefore, PARK7 may be a promising therapeutic target for APAP-induced liver injury.
1 March 2021 in Diabetes, Metabolic Syndrome and Obesity
Purpose: The prevalence of nonalcoholic fatty liver disease (NAFLD), which has recently become known as metabolic-associated fatty liver disease (MAFLD), has risen. However, pharmacotherapies for this disease have not been approved. Electromagnetic fields (EMFs) have excellent bioeffects on multiple diseases. However, the effects of EMFs on NAFLD are unknown. This study investigated the bioeffects of EMF exposure on insulin resistance, liver redox homeostasis and hepatic steatosis in db/db mice. Methods: Animals were sacrificed after EMF exposure for 8 weeks. The fasting blood glucose and insulin levels in the serum were tested. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated by a formula. The levels of MDA, GSSG and GSH, biomarkers of redox, were assessed. The activities of CAT, SOD and GSH-Px were assessed. The body and liver weights were measured. Hepatic lipid accumulation was observed by Oil Red O staining. Hepatic CAT, GR, GSH-Px, SOD1, SOD2 and SREBP-1 expression was determined by Western blotting. Results: EMF exposure ameliorated insulin resistance and oxidative stress in the liver by downregulating the MDA and GSSG levels, increasing the reduced GSH levels, and promoting the GSH-Px levels in db/db mice. In addition, liver weight and triglyceride (TG) levels were reduced by EMF exposure. Simultaneously, EMF exposure improved hepatic steatosis by downregulating the protein expression of SREBP-1c. Conclusion: The present findings suggest that EMF exposure has positive effects in the treatment of NAFLD.
Objective: Hexafluoropropylene oxide dimer acid (HFPO-DA), also known as GenX, is widely used globally, raising concerns about its safety and public health implications. However, its toxicity mechanism remains unclear. The purpose of this study was to develop a reliable method for detecting HFPO-DA in mice and to investigate its absorption, distribution, and impact on hepatic lipid metabolism. Method: HFPO-DA levels were measured in the serum and eight tissues of C57BL/6J mice after oral administration using ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS). Lipid metabolites in the liver were also detected and analyzed. Results: HFPO-DA was rapidly absorbed into the bloodstream and widely distributed throughout all tested tissues. It penetrated the blood–brain barrier, with the highest concentration in the liver; however, long-term effects on the lungs also warrant attention. HFPO-DA disrupted liver lipid metabolism, leading to acylcarnitine accumulation while lowering triglycerides and cholesterol. Conclusion: This study on the pharmacokinetics and tissue distribution of HFPO-DA in mice following oral exposure revealed that HFPO-DA exacerbates liver injury by altering hepatic lipid metabolism. These findings provide theoretical support for toxicological studies on the emerging environmental pollutant HFPO-DA.