Arsenic causes mitochondrial biogenesis obstacles by inhibiting the AMPK/PGC-1α signaling pathway and also induces apoptosis and dysregulated mitophagy in the duck liver

Proteomic-miRNA Biomics Profile Reveals 2D Cultures of Human iPSC-Derived Neural Progenitor Cells More Sensitive than 3D Spheroid System Against the Experimental Exposure to Arsenic

The iPSC-derived 3D models are considered to be a connective link between 2D culture and in vivo studies. However, the sensitivity of such 3D models is yet to be established. We assessed the sensitivity of the hiPSC-derived 3D spheroids against 2D cultures of neural progenitor cells. The sub-toxic dose of Sodium Arsenite (SA) was used to investigate the alterations in miRNA-proteins in both systems. Though SA exposure induced significant alterations in the proteins in both 2D and 3D systems, these proteins were uncommon except for 20 proteins. The number and magnitude of altered proteins were higher in the 2D system compared to 3D. The association of dysregulated miRNAs with the target proteins showed their involvement primarily in mitochondrial bioenergetics, oxidative and ER stress, transcription and translation mechanism, cytostructure, etc., in both culture systems. Further, the impact of dysregulated miRNAs and associated proteins on these functions and ultrastructural changes was compared in both culture systems. The ultrastructural studies revealed a similar pattern of mitochondrial damage, while the cellular bioenergetics studies confirm a significantly higher energy failure in the 2D system than to 3D. Such a higher magnitude of changes could be correlated with a higher amount of internalization of SA in 2D cultures than in 3D spheroids. Our findings demonstrate that a 2D culture system seems better responsive than a 3D spheroid system against SA exposure.

New insights into brain injury in chickens induced by bisphenol A and selenium deficiency-Mitochondrial reactive oxygen species and mitophagy-apoptosis crosstalk homeostasis

Bisphenol A (BPA), a component of plastic products, can penetrate the blood-brain barrier and pose a threat to the nervous system. Selenium (Se) deficiency can also cause nervous system damage. Resulting from the rapid industrial development, BPA pollution and Se deficiency often coexist. However, it is unclear whether brain damage in chickens caused by BPA exposure and Se deficiency is related to the crosstalk disorder between mitophagy and apoptosis. In this study, 60 chickens (1 day old) were fed with a diet that contained 20 mg/kg BPA but was insufficient in Se (only 0.039 mg/kg) for 42 days to establish a chicken brain injury model. In vitro, the primary chicken embryo brain neurons were treated for 24 h with Se-deficient medium containing 75 μM BPA. The results showed that BPA exposure and Se deficiency inhibited the expression of the mitochondrial respiratory chain complex in brain neurons, and a large number of mitochondrial reactive oxygen species were released. Furthermore, the expression levels of mitochondrial fusion proteins (OPA1, Mfn1, and Mfn2) decreased, while the expression levels of mitochondrial fission proteins (Drp1, Mff, and Fis1) increased, thus exacerbating mitochondrial division. In addition, the results of immunofluorescence and flow cytometry analysis, as well as the elevated expressions of mitophagy related genes (PINK1, Parkin, ATG5, and LC3II/I) and pro-apoptotic markers (Bax, Cytc, Caspase3, and Caspase9) indicated that BPA exposure and Se deficiency disrupted the crosstalk homeostasis between mitophagy and apoptosis. However, this crosstalk homeostasis was restored after Mito-Tempo and Rapamycin treatment. In contrast, 3-methyladenine treatment exacerbated this crosstalk disorder. In conclusion, BPA exposure and Se deficiency can induce mitochondrial reactive oxygen species bursts and disorders of mitochondrial dynamics by destroying the mitochondrial respiratory chain complex. The result is indicative of an imbalance in mitochondrial autophagy and apoptosis crosstalk homeostasis, which damages the chicken brain.

m6A methylation-mediated PGC-1α contributes to ferroptosis via regulating GSTK1 in arsenic-induced hepatic insulin resistance

Arsenic exposure has been closely linked to hepatic insulin resistance (IR) and ferroptosis with the mechanism elusive. Peroxisome proliferator γ-activated receptor coactivator 1-α (PGC-1α) is essential for glucose metabolism as well as for the production of reactive oxygen species (ROS). However, it was unclear whether there is a regulatory connection between PGC-1α and ferroptosis. Besides, the definitive mechanism of arsenic-induced hepatic IR progression remains to be determined. Here, we found that hepatic insulin sensitivity impaired by sodium arsenite (NaAsO2) could be reversed by inhibiting ferroptosis. Mechanistically, we found that PGC-1α suppression inhibited the protein expression of glutathione s-transferase kappa 1 (GSTK1) via nuclear respiratory factor 1 (NRF1), thereby increasing ROS accumulation and promoting ferroptosis. Furthermore, we showed that NaAsO2 induced hepatic IR and ferroptosis via methyltransferase-like 14 (METTL14) and YTH domain-containing family protein 2 (YTHDF2)-mediated N6-methyladenosine (m6A) of PGC-1α mRNA. In conclusion, NaAsO2-mediated PGC-1α suppression was m6A methylation-dependent and induced ferroptosis via the PGC-1α/NRF1/GSTK1 pathway in hepatic IR. The data might provide insight into potential targets for diabetes prevention and treatment.

Quercetin alleviates cadmium-induced BRL-3A cell apoptosis by inhibiting oxidative stress and the PERK/IRE1α/ATF6 signaling pathway

Cadmium (Cd) is a highly toxic environmental pollutant. The liver is an important metabolic organ in the body and is susceptible to Cd toxicity attacks. Quercetin (Que) is a flavonoid compound with pharmacological activities of scavenging free radicals and antioxidant activity. Previous studies have shown that Que can alleviate Cd caused hepatocyte apoptosis in rats, but the specific mechanism remains unclear. To explore the specific mechanism, we established a model of Cd toxicity and Que rescue in BRL-3A cells and used 4-phenylbutyrate (4-PBA), an endoplasmic reticulum stress (ERS) inhibitor, as positive control. Set up a control group, Cd treatment group, Cd and Que co treatment group, Que treatment group, Cd and 4-PBA co treatment group, and 4-PBA treatment group. Cell Counting Kit-8 (CCK-8) method was employed to measure cell viability. Fluorescence staining was applied to observe cell apoptosis. Flow cytometry was performed to detect reactive oxygen species levels. Real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot method was adopted to detect the mRNA and protein expression levels of ERS and apoptosis-related genes. The results showed that compared with the control group, the Cd treated group showed a significant decrease in cell viability (P < 0.01), an increase in intracellular ROS levels, and apoptosis. The mRNA and protein expression levels of ERS and apoptosis related factors such as GRP78, IRE1α, XBP1, ATF6, Caspase-12, Caspase-3 and Bax in the cells were significantly increased (P < 0.01), while the mRNA and protein expression levels of Bcl-2 were significantly reduced (P < 0.01). Compared with the Cd treatment group, the Cd and Que co treatment group and the Cd and 4-PBA co treatment group showed a significant increase in cell viability (P < 0.01), a decrease in intracellular ROS levels, a decrease in cell apoptosis, and a significant decrease in the expression levels of ERS and apoptosis related factors mRNA and protein (P < 0.01), as well as a significant increase in Bcl-2 mRNA and protein expression (P < 0.01). We confirmed that Que could alleviate the apoptosis caused by Cd in BRL-3A cells, and the effects of Que were similar to those of ERS inhibitor.

Reduced Peripheral Blood Mitochondrial DNA Copy Number as Identification Biomarker of Suspected Arsenic-Induced Liver Damage

Arsenic (As) can cause liver damage and liver cancer and is capable of seriously affecting human health. Therefore, it is important to identify biomarkers of arsenic-induced liver damage. Mitochondria are key targets of hepatotoxicity caused by arsenic. The mitochondrial DNA copy number (mtDNAcn) is the number of mitochondrial DNA (mtDNA) copies in the genome. mtDNA is vulnerable to exogenous chemical attacks, thus causing mtDNAcn to change after exposure to environmental pollutants. Therefore, mtDNAcn can serve as a potential marker to identify and assess the risk of diseases caused by exposure to environmental pollutants. In this study, we selected 272 arsenicosis patients (155 cases without liver damage and 117 cases with liver damage) and 218 participants not exposed to arsenic (155 cases without liver damage and 63 cases with liver damage) as subjects to investigate the correlation between peripheral blood mtDNAcn and arsenic-induced liver damage, as well as the ability of peripheral blood mtDNAcn to identify and assess the risk of arsenic-induced liver damage. Peripheral blood mtDNAcn in patients with arsenic-induced liver damage is significantly decreased and negatively correlated with serum ALT, AST, and GGT levels. The decrease of peripheral blood mtDNAcn was associated with an increased risk of arsenic-induced liver damage. The receiver operating characteristic (ROC) curve analysis indicated that peripheral blood mtDNAcn could specifically identify patients with liver damage in the arsenicosis group. The decision tree C5.0 model was established to identify arsenicosis in all patients with liver damage. Peripheral blood mtDNAcn was included in the model and played the most important role in the identification of arsenic-induced liver damage. This study provided a basis for the identification and evaluation of arsenic-induced liver damage by peripheral blood mtDNAcn, indicating that peripheral blood mtDNAcn is expected to be a potential biomarker of arsenic-induced liver damage, and provides clues for exploring the mechanism of arsenic-induced liver damage from mitochondria damage.

Ligand-Modified Gold Nanoparticles as Mitochondrial Modulators: Regulation of Intestinal Barrier and Therapy for Constipation

Intestinal metabolism-related diseases, such as constipation, inflammatory bowel disease, irritable bowel syndrome, and colorectal cancer, could be associated with the dysfunction of intestinal mitochondria. The mitochondria of intestinal epithelial cells are of great significance for promoting intestinal motility and maintaining intestinal metabolism. It is necessary for the prophylaxis and therapy of intestinal metabolism-related diseases to improve mitochondrial function. We investigated the effect of 4,6-diamino-2-pyrimidinethiol-modified gold nanoparticles (D-Au NPs) on intestinal mitochondria and studied the regulatory role of D-Au NPs on mitochondria metabolism-related disease. D-Au NPs improved the antioxidation capability of mitochondria, regulated the mitochondrial metabolism, and maintained intestinal cellular homeostasis via the activation of AMPK and regulation of PGC-1α with its downstream signaling (UCP2 and DRP1), enhancing the intestinal mechanical barrier. D-Au NPs improved the intestinal mitochondrial function to intervene in the emergence of constipation, which could help develop drugs to treat and prevent mitochondrial metabolism-related diseases. Our findings provided an in-depth understanding of the mitochondrial effects of Au NPs for improving human intestinal barriers.

Long-Term Copper Exposure Induced Excessive Autophagy of the Porcine Spleen

Copper (Cu) is one of the essential trace elements and is widespread in the environment. However, excessive exposure will induce toxicity in animals. To investigate the potential mechanisms of Cu-induced porcine spleen toxicity, sixty 30-day-old pigs were randomly divided into three groups. The control group was fed a basal diet and two treatment groups were separately fed the diet with 125 mg/kg and 250 mg/kg of Cu for 80 days. The result of immunohistochemical staining showed that the autophagy marker p62 was significantly increased under Cu exposure, and the immunofluorescence results showed the same trend as LC33-. Meanwhile, Cu intensified autophagy by increasing the expression levels of autophagy-related genes and proteins (LC3, p62, ATG5, Beclin1, and PINK1). These results suggested that long-term Cu exposure induced excessive autophagy in the porcine spleen, laying the groundwork for future studies on Cu-induced immunotoxicity in the spleen and increasing the public safety awareness of the excessive Cu-induced contamination in the environment.

Hepatorenal Toxicity of Inorganic Arsenic in White Pekin Ducks and Its Amelioration by Using Ginger

The toxic metalloid arsenic is known to cause liver and kidney injury in many humans and animals. The goal of this paper was to exemplify the antagonism of ginger against arsenic (As)-induced hepato-renal toxicity. In addition, the pathways Nrf2/Keap1 and NF/κB were studied to reveal the molecular mechanism of the stress. One hundred twenty 7-day-old White Pekin ducks were randomly allocated into five groups, having 24 birds in each. Each group contained three replicates having 8 birds in each replicate and maintained for 90 days. The groups were as follows: T-1 [control-basal diet with normal water], T-2 [T1 + As at 28 ppm/L of water], T-3 [T2 + ginger powder at 100 mg/kg feed], T-4 [T2 + ginger powder at 300 mg/kg feed], and T-5 [T2 + ginger powder at 1 g/kg feed]. It was observed that there was a significant increase in oxidative parameters whereas a significant decrease in antioxidant parameters in hepato-renal tissues in T-2. The exposure to As not only decreased the mRNA expression of antioxidant parameters like Nrf2, SOD-1, CAT, GPX, and HO-1and anti-inflammatory markers like IL-4 and IL-10 but also increased the m-RNA expression of NF-κB, Keap-1 and pro-inflammatory markers like IL-2, Il-6, IL-18, IL-1β, and TNF-α. There was also an accumulation of As in hepatic and renal tissue, confirmed by residual analysis of these tissues. By correlating the above parameters, As at 28 ppm showed significant toxic effects, and ginger powder at 1 g/kg feed effectively counteracted the toxic effects of As in ducks.

Combined effect of arsenic and polystyrene-nanoplastics at environmentally relevant concentrations in mice liver: Activation of apoptosis, pyroptosis and excessive autophagy

The ecological risks caused by the coexistence of pollutants such as arsenic (As) and polystyrene-nanoplastics (PSNPs) in the environment have become a non-negligible problem. However, the effects of As and PSNPs co-exposure on mammals and the underlying toxicity mechanisms have remained unclear. Therefore, the present study established mouse models of As and/or PSNPS exposure to systematically analyze the underlying role of autophagy, apoptosis and pyroptosis in hepatotoxicity induced by co-exposure of As and PSNPs. Our findings demonstrated for the first time that mice co-exposure to As and PSNPs displayed significant pathological changes in the liver, while exposure to As or PSNPs alone did not produce significant toxic effects. More importantly, As and PSNPs co-exposure activated excessive autophagy through altered expression levels of PI3K, mTOR, Beclin-1, ATG5, LC3 and P62. Meanwhile, co-treatment with As and PSNPs induced apoptosis in the liver, which was confirmed by ultrastructure observation and changes in the expression of apoptosis indicators (P53, Bax, Bcl-2, Caspase-3, Caspase-9, Cleaved-Caspase-3 and Cytc). Additionally, co-exposure of As and PSNPs induced pyroptosis in the liver through NLRP3/Caspase-1 pathway via targeting NLRP3, ASC, Pro-Caspase-1, GSDMD and Cleaved-Caspase-1 expressions. Overall, our findings provide deeper insight into the roles of apoptosis, pyroptosis and excessive autophagy in the aggravation of liver injury, which could contribute to a better understanding of the interactions between As and PSNPS exposure and the molecular mechanisms of hepatotoxicity.