NaAsO₂ regulates TLR4/MyD88/NF-κB signaling pathway through DNMT1/SOCS1 to cause apoptosis and inflammation in...

The exact molecular mechanism of arsenic-induced liver injury has not been fully elucidated. The aim of the study was to investigate the potential mechanism of NaAsO₂-induced cytotoxicity in BRL-3A cells and to provide a basis for the mechanism of arsenic poisoning. BRL-3A cells were treated with different doses of NaAsO₂, DNMT1 inhibitor (DC_517), TLR4 inhibitor (TAK-242), and transfection of SOCS1 plasmid. Cell activity, apoptosis, inflammation and protein expression of DNMT1, SOCS1, TLR4, MyD88, and NF-κB were detected by CCK8 assay, Annexin V-FITC and Western blot, respectively. With increasing NaAsO₂ doses, BAX and caspase-3 expression increased, Bcl-2 expression decreased, pro-inflammatory factors TNF-α, IL-1β, and IL-6 increased, and cell activity decreased causing increased apoptosis. When BRL-3A was intervened with 10, and 20 μmol/L NaAsO₂, DNMT1 expression was elevated, SOCS1 expression was decreased, and TLR4, MyD88, p-IκBα/IκBα, and p-p65/p65 expression were elevated. After the combination of NaAsO₂ and DC_517, compared to the NaAsO₂ group, apoptosis and inflammation were attenuated, SOCS1 expression was elevated and TLR4, MyD88, p-IκBα/IκBα and p-p65/p65 expression was decreased. Apoptosis and inflammation were attenuated after co-treatment of SOCS1 high expression with NaAsO₂ compared to the NaAsO₂ group. In addition, TLR4, MyD88, p-IκBα/IκBα and p-p65/p65 expression was reduced. When NaAsO₂ and TAK-242 were combined, apoptosis and inflammation were attenuated. Besides MyD88, p-IκBα/IκBα and p-p65/p65 expression was reduced compared to the NaAsO₂ group. We found that NaAsO₂ induce apoptosis and inflammation in BLR-3A cells, which may be related to inhibit SOCS1 through regulation of DNMT1 and thus activating the TLR4/MyD88/NF-κB signaling pathway.