Chen Long, Wang Ziwen, Wu Jie, Yao Quan, Peng Jingjing, Zhang Chi, Chen Hongdan, Li Yingjie, Jiang Zhongyong, Liu Yunsheng, Shi Chunmeng
State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Rocket Force Medicine Army Medical University Chongqing China.
Shigatse Branch, Xinqiao Hospital, Army 953 Hospital Army Medical University Shigatse China.
Clin Transl Immunology. 2023 Jun 17;12(6):e1452. doi: 10.1002/cti2.1452. eCollection 2023.
Intestinal mucositis is the major side effect during abdominal or pelvic radiotherapy, but the underlying immunogen remains to be further characterised and few radioprotective agents are available. This study investigated the role of dsDNA-triggered inflammasomes in intestinal mucositis during radiotherapy.
Pro-inflammatory cytokines were detected by ELISA. Radiation-induced intestinal injury in mice was analyzed by means of survival curves, body weight, HE staining of intestines, and intestinal barrier integrity. Western blot, immunofluorescence staining, co-immunoprecipitation assay and flow cytometry were used to investigate the regulatory role of dsDNA on inflammasomes.
Here, we show that a high level of IL-1β and IL-18 is associated with diarrhoea in colorectal cancer (CRC) patients during radiotherapy, which accounts for intestinal radiotoxicity. Subsequently, we found that the dose-dependently released dsDNA from the intestinal epithelial cells (IECs) serves as the potential immunogenic molecule for radiation-induced intestinal mucositis. Our results further indicate that the released dsDNA transfers into the macrophages in an HMGB1/RAGE-dependent manner and then triggers absent in melanoma 2 (AIM2) inflammasome activation and the IL-1β and IL-18 secretion. Finally, we show that the FDA-approved disulfiram (DSF), a newly identified inflammasome inhibitor, could mitigate intestinal radiotoxicity by controlling inflammasome.
These findings indicate that the extracellular self-dsDNA released from the irradiated IECs is a potential immunogen to stimulate immune cells and trigger the subsequent intestinal mucositis, while blunting the dsDNA-triggered inflammasome in macrophages may represent an exciting therapeutic strategy for side effects control during abdominal radiotherapy.
肠道黏膜炎是腹部或盆腔放疗期间的主要副作用，但潜在的免疫原仍有待进一步明确，且可用的放射防护剂很少。本研究调查了双链DNA（dsDNA）触发的炎性小体在放疗期间肠道黏膜炎中的作用。
通过酶联免疫吸附测定（ELISA）检测促炎细胞因子。通过生存曲线、体重、肠道苏木精-伊红（HE）染色和肠道屏障完整性分析小鼠辐射诱导的肠道损伤。采用蛋白质免疫印迹法、免疫荧光染色、免疫共沉淀分析和流式细胞术研究dsDNA对炎性小体的调节作用。
在此，我们表明高水平的白细胞介素-1β（IL-1β）和白细胞介素-18与直肠癌（CRC）患者放疗期间的腹泻相关，这是肠道放射毒性的原因。随后，我们发现肠道上皮细胞（IECs）剂量依赖性释放的dsDNA作为辐射诱导肠道黏膜炎的潜在免疫原性分子。我们的结果进一步表明，释放的dsDNA以高迁移率族蛋白B1（HMGB1）/晚期糖基化终末产物受体（RAGE）依赖性方式转移到巨噬细胞中，然后触发黑色素瘤缺乏因子2（AIM2）炎性小体激活以及IL-1β和IL-18分泌。最后，我们表明美国食品药品监督管理局（FDA）批准的双硫仑（DSF），一种新鉴定的炎性小体抑制剂，可以通过控制炎性小体减轻肠道放射毒性。
这些发现表明，受辐射的IECs释放的细胞外自身dsDNA是刺激免疫细胞并引发随后肠道黏膜炎的潜在免疫原，而抑制巨噬细胞中dsDNA触发的炎性小体可能是腹部放疗期间控制副作用的一种令人兴奋的治疗策略。
