Abstract：
Sepsis is a systemic inflammatory response syndrome caused by infection, which causes renal dysfunction known as sepsis-associated acute kidney injury (S-AKI). Ferroptosis is a form of lipid peroxidation dependent on iron and reactive oxygen species that differs from other forms of programmed cell death at the morphological and biochemical levels. Andrographolide (AG), a natural diterpenoid lactone compound extracted from Andrographis paniculata, has been shown to have therapeutic effects in kidney disease. In this study, we investigated the novel mechanism by which AG attenuates septic acute kidney injury by inhibiting ferroptosis in renal tubular epithelial cells (HK-2) through the Nrf2/FSP1 pathway. Cecum ligation and puncture (CLP)-induced septic rats and lipopolysaccharide (LPS)-induced HK-2 cells were used for in vivo and in vitro experiments. Firstly, in septic rats and HK-2 cells, AG effectively decreased the levels of kidney injury indicators, including blood creatinine, urea nitrogen, and markers of kidney injury such as neutrophil gelatinase-associated lipid transport protein and kidney injury molecule-1 (KIM-1). In addition, AG prevented ferroptotosis, by avoiding the accumulation of iron and lipid peroxidation, and an increase in SLC7A11 and GPX4 in AG-treated HK-2 cells. Furthermore, AG attenuated mitochondrial damage, including mitochondrial swelling, outer membrane rupture, and a reduction in mitochondrial cristae in LPS-treated HK-2 cells. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, significantly inhibited LPS-induced ferroptosis in HK-2 cells. Importantly, our results confirm that Nrf2/FSP1 is an important pathway for ferroptosis resistance. Nrf2 siRNA hindered the effect of AG in attenuating acute kidney injury and inhibiting ferroptosis. These findings demonstrate that Nrf2/FSP1-mediated HK-2 ferroptosis is associated with AG, alleviates septic acute kidney injury, and indicates a novel avenue for therapeutic interventions in the treatment of acute kidney injury in sepsis.
摘要：
脓毒症是由感染引起的全身性炎症反应综合征,导致肾功能障碍，称为脓毒症相关急性肾损伤（S-AKI）。铁凋亡是一种依赖于铁和活性氧的脂质过氧化形式，在形态和生化水平上不同于其他形式的程序性细胞死亡。穿心莲内酯(AG),从穿心莲中提取的天然二萜内酯化合物，已被证明对肾脏疾病有治疗作用。在这项研究中,我们研究了AG通过Nrf2/FSP1途径抑制肾小管上皮细胞(HK-2)的铁凋亡,从而减轻脓毒症急性肾损伤的新机制.盲肠结扎和穿刺（CLP）诱导的脓毒症大鼠和LPS诱导的HK-2细胞用于体内和体外实验。首先,在败血症大鼠和HK-2细胞中，AG有效降低肾损伤指标水平，包括血肌酐，尿素氮,和肾损伤标志物，如中性粒细胞明胶酶相关脂质转运蛋白（NGAL）和肾损伤分子-1（KIM-1）。此外,AG预防肥大病，通过避免铁和脂质过氧化的积累，和AG处理的HK-2细胞中SLC7A11和GPX4的增加。此外，AG减弱线粒体损伤，包括线粒体肿胀,外膜破裂,和LPS处理的HK-2细胞中线粒体cr的减少。Ferrostatin-1(Fer-1),一种铁凋亡抑制剂，显著抑制LPS诱导的HK-2细胞的铁凋亡。重要的是,我们的结果证实Nrf2/FSP1是铁凋亡抗性的重要通路。Nrf2siRNA阻碍了AG减轻急性肾损伤和抑制铁凋亡的作用。这些发现表明Nrf2/FSP1介导的HK-2铁凋亡与AG有关。减轻脓毒症急性肾损伤，并为脓毒症急性肾损伤的治疗提供了新的途径。
