Astragalus Polysaccharide Alleviated Septic Associated Acute Kidney Injury Through Dual Mechanisms of RIPK1-Dependent Necroptosis and Autophagy in Macrophage.

Acute kidney injury (AKI) is a significant risk factor for high morbidity and disability in patients with sepsis, where systemic inflammation and immune dysregulation are key drivers of sepsis-associated AKI (SA-AKI). Astragalus polysaccharide (AP), a natural, low-toxicity compound derived from Traditional Chinese Medicine Astragalus membranaceus (AM), possesses notable anti-inflammatory and immunoregulatory activities. This study was therefore designed to investigate the role of AP in SA-AKI, specifically focusing on its underlying anti-inflammatory mechanism. To elucidate the core inflammatory pathology driving SA-AKI, we established an LPS/zVAD-induced endotoxemia mouse model and a corresponding LPS/zVAD-stimulated Raw264.7 macrophage model. The renoprotective effect of AP and its underlying mechanisms were systematically investigated using H&E, ELISA, RT-qPCR, Western blot, immunofluorescence, and siRNA silencing. In vivo results suggested that AP improved renal dysfunction and inflammation in LPS/zVAD-induced septic mice. Furthermore, AP inhibited RIPK1/RIPK3/MLKL activation and restored autophagic flux in renal macrophages of SA-AKI mice. In vitro, AP suppressed LPS/zVAD-induced cell death and inflammatory cytokine expression by inhibiting the RIPK1/RIPK3/MLKL pathway. Concurrently, AP alleviated LPS/zVAD-induced autophagy dysfunction by promoting TFEB nuclear translocation, an effect potentially mediated by RIPK1. Consistently, downregulation of TFEB expression in the kidney tissue of septic mice was reversed following AP administration. Collectively, AP demonstrated a therapeutic effect against SA-AKI. Mechanistically, this effect was associated with the modulation of RIPK1, as AP concurrently inhibited necroptosis and restored autophagic flux via TFEB activation, both of which are RIPK1-dependent processes. This dual modulation ultimately attenuated macrophage inflammation.