The Second Affiliated Hospital, The State Key Laboratory of Respiratory Disease, Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, Guangzhou Medical University, 510260, Guangzhou, China.
The First Affiliated Hospital, Guangdong Pharmaceutical University, 510006, Guangzhou, China.
Cell Death Dis. 2019 Apr 24;10(5):344. doi: 10.1038/s41419-019-1580-7.
Necroptosis of intestinal epithelial cells has been indicated to play an important role in the pathogenesis of inflammatory bowel disease (IBD). The identification of dysregulated proteins that can regulate necroptosis in dextran sulfate sodium (DSS)-induced colitis is the key to the rational design of therapeutic strategies for colitis. Through tandem mass tag (TMT)-based quantitative proteomics, HtrA2 was found to be downregulated in the colon of DSS-treated mice. UCF-101, a specific serine protease inhibitor of HtrA2, significantly alleviated DSS-induced colitis as indicated by prevention of body weight loss and decreased mortality. UCF-101 decreased DSS-induced colonic inflammation, prevented intestinal barrier function loss and inhibited necroptosis of intestinal epithelial cells. In vitro, UCF-101 or silencing of HtrA2 decreased necroptosis of HT-29 and L929 cells. UCF-101 decreased phosphorylation of RIPK1 and subsequent phosphorylation of RIPK3 and MLKL during necroptosis. Upon necroptotic stimulation, HtrA2 translocated from mitochondria to cytosol. HtrA2 directly interacted with RIPK1 and promoted its degradation during a specific time phase of necroptosis. Our findings highlight the importance of HtrA2 in regulating colitis by modulation of necroptosis and suggest HtrA2 as an attractive target for anti-colitis treatment.
肠上皮细胞的坏死性凋亡被认为在炎症性肠病（IBD）的发病机制中起重要作用。鉴定可调节葡聚糖硫酸钠（DSS）诱导的结肠炎中坏死性凋亡的失调蛋白是为结肠炎设计合理治疗策略的关键。通过串联质量标签（TMT）定量蛋白质组学，发现 HtrA2 在 DSS 处理的小鼠结肠中下调。UCF-101 是 HtrA2 的特异性丝氨酸蛋白酶抑制剂，可显著缓解 DSS 诱导的结肠炎，表现为体重减轻和死亡率降低的预防。UCF-101 降低 DSS 诱导的结肠炎症，防止肠道屏障功能丧失并抑制肠上皮细胞的坏死性凋亡。在体外，UCF-101 或 HtrA2 的沉默降低 HT-29 和 L929 细胞的坏死性凋亡。UCF-101 在坏死性凋亡过程中降低 RIPK1 的磷酸化以及随后的 RIPK3 和 MLKL 的磷酸化。在坏死性凋亡刺激下，HtrA2 从线粒体易位到细胞质。HtrA2 与 RIPK1 直接相互作用，并在坏死性凋亡的特定时间阶段促进其降解。我们的研究结果强调了 HtrA2 通过调节坏死性凋亡在调节结肠炎中的重要性，并表明 HtrA2 作为抗结肠炎治疗的有吸引力的靶标。
