Colistin is commonly regarded as the “last-resort” antibiotic for combating life-threatening infections caused by multidrug-resistant (MDR) gram-negative bacteria. Neurotoxicity is a potential adverse event associated with colistin application in clinical settings, yet the exact molecular mechanisms remain unclear. This study examined the detrimental impact of colistin exposure on PC12 cells and the associated molecular mechanisms. Colistin treatment at concentrations of 0–400 μM decreased cell viability and induced apoptotic cell death in both time- and concentration-dependent manners. Exposure to colistin triggered the production of reactive oxygen species (ROS) and caused oxidative stress damage in PC12 cells. N-acetylcysteine (NAC) supplementation partially mitigated the cytotoxic and apoptotic outcomes of colistin. Evidence of mitochondrial dysfunction was observed through the dissipation of membrane potential. Additionally, colistin treatment upregulated the expression of AhR and CYP1A1 mRNAs in PC12 cells. Pharmacological inhibition of AhR (e.g., using α-naphthoflavone) or intervention with the CYP1A1 gene significantly decreased the production of ROS induced by colistin, subsequently lowering caspase activation and cell apoptosis. In conclusion, our findings demonstrate, for the first time, that the activation of the AhR/CYP1A1 pathway contributes partially to colistin-induced oxidative stress and apoptosis, offering insights into the cytotoxic effects of colistin.

Chelerythrine (CHE) is a majorly harmful isoquinoline alkaloid ingredient in Chelidonium majus that could trigger potential hepatotoxicity, but the pivotal molecular mechanisms remain largely unknown. In the present study, CHE-induced cytotoxicity and the underlying toxic mechanisms were investigated using human HepG2 cells in vitro. Data showed that CHE treatment (at 1.25–10 μM)-induced cytotoxicity in HepG2 cells is dose-dependent. CHE treatment increased the production of ROS and induced oxidative stress in HepG2 cells. Additionally, CHE treatment triggered the loss of mitochondrial membrane potential, decreased the expression of mitochondrial complexes, upregulated the expression of Bax, CytC, and cleaved-PARP1 proteins and the activities of caspase-9 and caspase-3, and downregulated the expression of Bcl-XL, and HO-1 proteins, finally resulting in cell apoptosis. N-acetylcysteine supplementation significantly inhibited CHE-induced ROS production and apoptosis. Furthermore, CHE treatment significantly downregulated the expression of phosphorylation (p)-Akt (Ser473), p-mTOR (Ser2448), and p-AMPK (Thr172) proteins in HepG2 cells. Pharmacology inhibition of Akt promoted CHE-induced the downregulation of HO-1 protein, caspase activation, and apoptosis. In conclusion, CHE-induced cytotoxicity may involve the inhibition of Akt pathway and the activation of oxidative stress-mediated mitochondrial apoptotic pathway in HepG2 cells. This study sheds new insights into understanding the toxic mechanisms and health risks of CHE.

Cisplatin (CDDP), an important chemotherapeutic agent, could result in potential hepatotoxicity, but the precious molecular mechanisms remain unclear. In this study, the protective effect of ellagic acid (EA) on CDDP exposure-induced hepatotoxicity and underlying molecular mechanisms were investigated using a mouse model. Mice were randomly divided into control, CDDP model, EA100 (i.e., EA 100 mg/kg/day), and CDDP plus EA 25, 50, and 100 mg/kg/day. Mice in all CDDP-treated groups were intraperitoneally injected with CDDP 20 mg/kg/day for 2 days. In all EA co-treatments, mice were orally administrated with EA for 7 days. Our results found that, compared to the control group, CDDP treatment resulted in liver dysfunction, oxidative stress, and hepatocyte necrosis, which are effectively revised by EA supplementation in a dose-dependent manner. Meanwhile, EA supplementation inhibited CDDP-induced the elevation of caspases-9 and -3 activities in the liver tissues of mice. Furthermore, EA supplementation significantly downregulated CDDP exposure-induced the increases of NF-κB, IL-1β, TNF-α, and IL-6 proteins and mRNAs, while further upregulated the expression of Nrf2, and HO-1 proteins and mRNAs. Taken together, our results reveal that EA supplementation could ameliorate CCDP-induced liver injury in mice via the opposite regulation of Nrf2/HO-1 and NF-kB pathways.