Abstract：
BACKGROUND: Intestinal immune dysregulation is strongly linked to the occurrence and formation of tumors. RING finger protein 128 (RNF128) has been identified to play distinct immunoregulatory functions in innate and adaptive systems. However, the physiological roles of RNF128 in intestinal inflammatory conditions such as colitis and colorectal cancer (CRC) remain controversial.
OBJECTIVE: To elucidate the function and mechanism of RNF128 in colitis and CRC.
METHODS: Animal models of dextran sodium sulfate (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced CRC were established in WT and Rnf128-deficient mice and evaluated by histopathology. Co-immunoprecipitation and ubiquitination analyses were employed to investigate the role of RNF128 in IL-6-STAT3 signaling.
RESULTS: RNF128 was significantly downregulated in clinical CRC tissues compared with paired peritumoral tissues. Rnf128-deficient mice were hypersusceptible to both colitis induced by DSS and CRC induced by AOM/DSS or APC mutation. Loss of RNF128 promoted the proliferation of CRC cells and STAT3 activation during the early transformative stage of carcinogenesis in vivo and in vitro when stimulated by IL-6. Mechanistically, RNF128 interacted with the IL-6 receptor α subunit (IL-6Rα) and membrane glycoprotein gp130 and mediated their lysosomal degradation in ligase activity-dependent manner. Through a series of point mutations in the IL-6 receptor, we identified that RNF128 promoted K48-linked polyubiquitination of IL-6Rα at K398/K401 and gp130 at K718/K816/K866. Additionally, blocking STAT3 activation effectively eradicated the inflammatory damage of Rnf128-deficient mice during the transformative stage of carcinogenesis.
CONCLUSIONS: RNF128 attenuates colitis and colorectal tumorigenesis by inhibiting IL-6-STAT3 signaling, which sheds novel insights into the modulation of IL-6 receptors and the inflammation-to-cancer transition.
OBJECTIVE: To elucidate the function and mechanism of RNF128 in colitis and CRC.
METHODS: Animal models of dextran sodium sulfate (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced CRC were established in WT and Rnf128-deficient mice and evaluated by histopathology. Co-immunoprecipitation and ubiquitination analyses were employed to investigate the role of RNF128 in IL-6-STAT3 signaling.
RESULTS: RNF128 was significantly downregulated in clinical CRC tissues compared with paired peritumoral tissues. Rnf128-deficient mice were hypersusceptible to both colitis induced by DSS and CRC induced by AOM/DSS or APC mutation. Loss of RNF128 promoted the proliferation of CRC cells and STAT3 activation during the early transformative stage of carcinogenesis in vivo and in vitro when stimulated by IL-6. Mechanistically, RNF128 interacted with the IL-6 receptor α subunit (IL-6Rα) and membrane glycoprotein gp130 and mediated their lysosomal degradation in ligase activity-dependent manner. Through a series of point mutations in the IL-6 receptor, we identified that RNF128 promoted K48-linked polyubiquitination of IL-6Rα at K398/K401 and gp130 at K718/K816/K866. Additionally, blocking STAT3 activation effectively eradicated the inflammatory damage of Rnf128-deficient mice during the transformative stage of carcinogenesis.
CONCLUSIONS: RNF128 attenuates colitis and colorectal tumorigenesis by inhibiting IL-6-STAT3 signaling, which sheds novel insights into the modulation of IL-6 receptors and the inflammation-to-cancer transition.
摘要：
背景：肠道免疫失调与肿瘤的发生和形成密切相关。环指蛋白128(RNF128)已被鉴定为在先天和适应性系统中发挥不同的免疫调节功能。然而,RNF128在结肠炎和结直肠癌(CRC)等肠道炎症中的生理作用仍存在争议.
目的：阐明RNF128在结肠炎和CRC中的作用和机制。
方法：在WT和Rnf128缺陷小鼠中建立葡聚糖硫酸钠（DSS）诱导的结肠炎和氧化甲烷（AOM）/DSS诱导的CRC动物模型，并通过组织病理学进行评估。采用免疫共沉淀和泛素化分析来研究RNF128在IL-6-STAT3信号传导中的作用。
结果：与配对的肿瘤周围组织相比，RNF128在临床CRC组织中显著下调。Rnf128缺陷型小鼠对DSS诱导的结肠炎和AOM/DSS或APC突变诱导的CRC均高度敏感。当IL-6刺激时，RNF128的缺失在体内和体外癌变的早期转化阶段促进了CRC细胞的增殖和STAT3的激活。机械上,RNF128与IL-6受体α亚基（IL-6Rα）和膜糖蛋白gp130相互作用，并以连接酶活性依赖性方式介导其溶酶体降解。通过一系列IL-6受体的点突变,我们发现RNF128在K398/K401促进IL-6Rα的K48连接多泛素化,在K718/K816/K866促进gp130。此外,阻断STAT3激活可有效根除Rnf128缺陷小鼠在癌变转化阶段的炎症损伤。
结论：RNF128通过抑制IL-6-STAT3信号传导减弱结肠炎和结直肠肿瘤发生，这为IL-6受体的调节和炎症到癌症的转变提供了新的见解。
目的：阐明RNF128在结肠炎和CRC中的作用和机制。
方法：在WT和Rnf128缺陷小鼠中建立葡聚糖硫酸钠（DSS）诱导的结肠炎和氧化甲烷（AOM）/DSS诱导的CRC动物模型，并通过组织病理学进行评估。采用免疫共沉淀和泛素化分析来研究RNF128在IL-6-STAT3信号传导中的作用。
结果：与配对的肿瘤周围组织相比，RNF128在临床CRC组织中显著下调。Rnf128缺陷型小鼠对DSS诱导的结肠炎和AOM/DSS或APC突变诱导的CRC均高度敏感。当IL-6刺激时，RNF128的缺失在体内和体外癌变的早期转化阶段促进了CRC细胞的增殖和STAT3的激活。机械上,RNF128与IL-6受体α亚基（IL-6Rα）和膜糖蛋白gp130相互作用，并以连接酶活性依赖性方式介导其溶酶体降解。通过一系列IL-6受体的点突变,我们发现RNF128在K398/K401促进IL-6Rα的K48连接多泛素化,在K718/K816/K866促进gp130。此外,阻断STAT3激活可有效根除Rnf128缺陷小鼠在癌变转化阶段的炎症损伤。
结论：RNF128通过抑制IL-6-STAT3信号传导减弱结肠炎和结直肠肿瘤发生，这为IL-6受体的调节和炎症到癌症的转变提供了新的见解。
