WTAP mediates the anti-inflammatory effect of Astragalus mongholicus polysaccharide on THP-1 macrophages
Haijiao Long, Haiyue Lin, Pan Zheng, Lianjie Hou, Ming Zhang, Shuyun Lin, Kai Yin, Guojun Zhao
Abstract
Background: Astragalus mongholicus polysaccharides (APS) have anti-inflammatory, antioxidant and immunomodulatory effects. Recent studies have demonstrated the epigenetic regulation of N6-methyladenosine (m 6 A) in the development of inflammation. However, the effect of APS on m 6 A modification is unclear. Here, for the first time, we investigate the mechanism of m 6 A modification in APS regulation of THP-1 macrophage inflammation. Methods: We treated LPS-induced THP-1 macrophages with APS at different concentrations and times, and detected IL-6 mRNA and protein levels by quantitative real-time PCR (qRT-PCR) and western blot, respectively. The m 6 A modification level was detected by m 6 A quantification kit. The proteins that regulate m 6 A modification were screened by western blot. Wilms’ tumor 1-associating protein (WTAP) was overexpressed in APS-treated THP-1 macrophages and the m 6 A modification level and IL-6 expressions were detected. Results: These findings confirmed that APS significantly abolished LPS-induced IL-6 levels in THP-1 macrophages. Meanwhile, APS reduced m 6 A modification levels and WTAP gene expression in THP-1 macrophages. Further overexpression of WTAP can significantly reverse APS-induced m 6 A modification level and IL-6 expression. Mechanistically, APS regulates IL-6 expression through WTAP-mediated p65 nuclear translocation. Conclusion: Overall, our study suggested that WTAP mediates the anti-inflammatory effect of APS by regulating m 6 A modification levels in THP-1 macrophages. This study reveals a new dimension of APS regulation of inflammation at the epigenetic level.