Targeting STAT3 with Conditional Knockout or PROTAC Technology Alleviates Renal Injury by Limiting Pyroptosis [ChIP-seq]

The role of signal transducer and activator of transcription protein 3 (STAT3) in AKI remains controversial. Our study demonstrated an upregulation of total STAT3 protein in AKI mouse models induced by cecal ligation and puncture (CLP) or ischemia-reperfusion (I/R), correlating with patient biopsy results. This increase may be attributed to histone H3K27 acetylation. STAT3 knockout in renal tubular epithelial cells significantly reduced AKI injury and inflammation in mice. Mechanistically, STAT3 induces the transcription of tripartite motif-containing protein 21 (TRIM21), triggering a cascade that activates gasdermin D (GSDMD), resulting in pyroptosis. Administration of the novel proteolysis-targeting chimera (PROTAC) compound E034, which selectively targets STAT3 for ubiquitination and degradation, significantly alleviated renal injury in a low-dose, single-dose regimen, underscoring its substantial therapeutic potential with infrequent dosing requirements. In the context of renal injury, PROTAC emerges as a promising modality by specifically targeting the STAT3/TRIM21/GSDMD axis, which our study has identified as a potential therapeutic target, thereby potentially endowing novel and clinically significant therapeutic strategies. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for the control group of mTEC cells stimulated by LPS and the STAT3 silenced group.

信号转导与转录激活因子3（signal transducer and activator of transcription protein 3, STAT3）在急性肾损伤（acute kidney injury, AKI）中的作用仍存在争议。本研究证实，在盲肠结扎穿刺术（cecal ligation and puncture, CLP）或缺血再灌注（ischemia-reperfusion, I/R）诱导的AKI小鼠模型中，总STAT3蛋白表达上调，且该变化与临床患者的活检结果具有相关性。该蛋白表达上调可能与组蛋白H3K27乙酰化有关。在小鼠肾小管上皮细胞中敲除STAT3，可显著减轻AKI小鼠的肾损伤与炎症反应。机制研究显示，STAT3可诱导含三结构域蛋白21（tripartite motif-containing protein 21, TRIM21）的转录，进而触发级联反应以活化成孔蛋白D（gasdermin D, GSDMD），最终引发细胞焦亡。本研究使用新型蛋白水解靶向嵌合体（proteolysis-targeting chimera, PROTAC）化合物E034——该化合物可特异性靶向STAT3并介导其泛素化降解——采用低剂量单次给药方案给药后，可显著缓解小鼠肾损伤，这充分体现了其给药频率低的显著治疗潜力。在肾损伤的病理背景下，PROTAC通过特异性靶向本研究已确认的潜在治疗靶点STAT3/TRIM21/GSDMD信号轴，展现出极具前景的治疗策略，有望为临床提供全新且具有重要临床价值的治疗方案。本研究还针对脂多糖（lipopolysaccharide, LPS）刺激的mTEC细胞对照组与STAT3沉默组开展了染色质免疫沉淀测序（Chromatin immunoprecipitation DNA-sequencing, ChIP-seq）。