HIF1α/miR-146α/TRAF6/NF-κB axis modulates hepatic iron overload-induced inflammation

Proteomics-Based Exploration of the Hepatoprotective Mechanism of α-Lipoic Acid in Rats with Iron Overload-Induced Liver Injury

Excessive iron accumulation poses a significant threat to liver health, primarily through oxidative stress and autophagy dysregulation. α-Lipoic acid (ALA), a natural antioxidant with hepatoprotective properties, may alleviate iron-induced liver damage, but its underlying mechanisms are not fully understood. This study utilized male Sprague Dawley rats and BRL-3A cells to explore the protective effects of ALA against iron overload in vivo and in vitro, respectively. ALA treatment significantly reduced hepatic iron accumulation, improved liver morphology, and alleviated iron-induced ultrastructural damage in rats. ALA also improved liver function markers in plasma, including alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), total bilirubin (TBIL), and the AST/ALT ratio. Furthermore, ALA mitigated iron-induced oxidative stress by lowering hepatic reactive oxygen species (ROS) and malondialdehyde (MDA), while increasing the antioxidant enzyme activities of glutathione peroxidase (GSH-Px) and catalase (CAT). In BRL-3A cells, ALA improved cell viability, decreased intracellular ROS, and reduced iron levels. Proteomics analysis indicates that NAD(P)H: quinone oxidoreductase 1 (NQO1) may play a critical role in the protective effects of ALA against iron overload-induced hepatic damage in rats. Mechanistically, ALA upregulated NQO1 expression while downregulating autophagy-related proteins, including light chain 3B (LC3B), lysosomal-associated membrane protein 1 (LAMP1), and cathepsin D (CTSD). Inhibition or knockdown of NQO1 abolished ALA's protective effects, confirming its role in reducing oxidative stress and excessive autophagy. These findings highlight the potential of ALA as a therapeutic agent for managing hepatic iron toxicity through iron chelation and activation of NQO1.

MiR-146a-5p downregulated TRAF6/NF-κB p65 pathway to attenuate the injury of HT-22 cells induced by oxygen-glucose deprivation/reoxygenation

MicroRNA-146a-5p (miR-146a-5p) actively participates in the process of cerebral ischemia-reperfusion (CI/R) injury. Dysregulation of the tumor necrosis factor receptor-associated factor 6 (TRAF6)/nuclear factor kappa-B (NF-κB) p65 axis is closely associated with inflammatory response. This study aimed to investigate the potential involvement of miR-146a-5p and TRAF6/NF-κB p65 in mediating CI/R progression in vitro. HT-22 cells were challenged with oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate CI/R in vitro. HT-22 cells were transfected with miR-146a-5p mimics or TRAF6 overexpression constructs. The impact of miR-146a-5p on apoptosis, inflammation, and TRAF6/NF-κB p65 activation were investigated. OGD/R inhibited HT-22 cell viability, induced apoptosis, reduced miR-146a-5p levels and activated the TRAF6/NF-κB p65 pathway. MiR-146a-5p mimics reduced pro-inflammatory factor release, limited apoptosis-related protein expression, and inactivated the TRAF6/NF-κB p65 pathway in OGD/R-challenged HT-22 cells. Mechanistically, miR-146a-5p was verified to bind to TRAF6 3'UTR. TRAF6 overexpression reversed the beneficial effects of miR-146a-5p mimics on apoptosis, inflammation, and TRAF6/NF-κB p65 activation. This work revealed that miR-146a-5p targeted TRAF6 and suppressed the TRAF6/NF-κB p65 pathway, thereby reducing OGD/R-induced inflammation and apoptosis in HT-22 cells. These findings suggest the potential of the miR-146a-5p/TRAF6/NF-κB p65 axis in the treatment of CI/R.