Sediment pollutant exposures caused hepatotoxicity and disturbed glycogenesis.

Liver metabolic syndrome, which involves impaired hepatic glycogen synthesis, is persistently increased by exposure to environmental pollutants. Most studies have investigated the pathogenesis of liver damage caused by single metal species or pure organics. However, under normal circumstances, the pollutants that we are exposed to are usually chemical mixtures that accumulate over time. Sediments are long-term repositories for environmental pollutants due to their environmental cycles, which make them good samples for evaluating the effect of environmental pollutants on the liver via bioaccumulation. This study aimed to clarify the effects of sediment pollutants on liver damage. Our results indicate that industrial wastewater sediment (downstream) is more cytotoxic than sediments from other zones. Downstream sediment extract (DSE) causes hepatotoxicity, stimulates reactive oxygen species (ROS) generation, triggers mitochondrial dysfunction, induces cell apoptosis, and results in the release of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) proteins. Additionally, to elucidate the underlying mechanism by which sediment pollutants disturb hepatic glycogen synthesis, we investigated the effects of different sediment samples from different pollution situations on glycogen synthesis in liver cell lines. It was found that DSE induced multiple severe impairments in liver cells, and disturbed glycogen synthesis more than under other conditions. These impairments include decreased hepatic glycogen synthesis via inhibition and insulin receptor substrate 1 (IRS-1) /AKT /glycogen synthase kinase3ß (GSK3ß)-mediated glycogen synthase (GYS) inactivation. To our knowledge, this study provides the first detailed evidence of in vitro sediment-accumulated toxicity that interferes with liver glycogen synthesis, leading to hepatic cell damage through apoptosis.

Characterization of TGF-ß by Induced Oxidative Stress in Human Trabecular Meshwork Cells.

Oxidative stress generated by reactive oxygen species (ROS) plays a critical role in the pathomechanism of glaucoma, which is a multifactorial blinding disease that may cause irreversible damage within human trabecular meshwork cells (HTMCs). It is known that the transforming growth factor-ß (TGF-ß) signaling pathway is an important component of oxidative stress-induced damage related to extracellular matrix (ECM) fibrosis and activates cell antioxidative mechanisms. To elucidate the dual potential roles and regulatory mechanisms of TGF-ß in effects on HTMCs, we established an in vitro oxidative model using hydrogen peroxide (H2O2) and further focused on TGF-ß-related oxidative stress pathways and the related signal transduction. Via a series of cell functional qualitative analyses to detect related protein level alterations and cell fibrosis status, we illustrated the role of TGF-ß1 and TGF-ß2 in oxidative stress-induced injury by shTGF-ß1 and shTGF-ß2 knockdown or added recombinant human TGF-ß1 protein (rhTGF-ß1). The results of protein level showed that p38 MAPK, TGF-ß, and its related SMAD family were activated after H2O2 stimulation. Cell functional assays showed that HTMCs with H2O2 exposure duration had a more irregular actin architecture compared to normal TM cells. Data with rhTGF-ß1 (1 ng/mL) pretreatment reduced the cell apoptosis rate and amount of reactive oxygen species (ROS), while it also enhanced survival. Furthermore, TGF-ß1 and TGF-ß2 in terms of antioxidant signaling were related to the activation of collagen I and laminin, which are fibrosis-response proteins. Succinctly, our study demonstrated that low concentrations of TGF-ß1 (1 ng/mL) preserves HTMCs from free radical-mediated injury by p-p38 MAPK level and p-AKT signaling balance, presenting a signaling transduction mechanism of TGF-ß1 in HTMC oxidative stress-related therapies.