海藻希瓦氏菌及其特异性脂多糖对结直肠腺瘤的影响及机制

The effect of lipopolysaccharide from Shewanella algae on the occurrence and development of colorectal adenoma

目的探讨海藻希瓦氏菌(Shewanella algae,S.algae)及其特异性脂多糖(lipopolysaccharide,LPS)对结直肠腺瘤(colorectal adenoma,CRA)的影响及机制。方法将24只C57BL/6J雌性小鼠分成4组:Control组、AOM/DSS组、AOM/DSS+LPS组、AOM/DSS+S.algae组。S.algae及其LPS采用灌胃干预,qRT-PCR和免疫组化法检测小鼠巨噬细胞水平及腺瘤细胞的增殖、周期改变。qRT-PCR和ELISA法评估肿瘤炎性微环境的改变。Western Blot检测小鼠TLR4/NF-κB通路蛋白的表达。体外实验验证M1巨噬细胞和S.algae特异性LPS对结直肠肿瘤细胞增殖、迁移和周期的影响。结果与AOM/DSS组相比,S.algae及其LPS干预后的肠上皮细胞不典型增生程度和M1巨噬细胞水平均升高,细胞增殖和周期蛋白表达增加,促炎因子水平升高,并激活了TLR4/NF-κB通路。体外共培养实验表明,S.algae及其LPS可能通过巨噬细胞促进结直肠肿瘤细胞的增殖、迁移和细胞周期。结论 S.algae特异性LPS可能通过M1巨噬细胞促进结直肠腺瘤的发生和发展。

Objective To investigate the effect and mechanism of Shewanella algae(S.algae)and its specific lipopolysaccharide(LPS)on colorectal adenoma(CRA). Methods Twenty-four female C57 BL/6 J mice were divided into four groups:the control group,the AOM/DSS group,the AOM/DSS+LPS group,and the AOM/DSS+S.algae group. q RT-PCR and immunohistochemistry(IHC)were used to detect the level of macrophages and the proliferation and cycle of tumor cells in mice. qRT-PCR and ELISA were used to evaluate the change of tumor inflammatory microenvironment. The expression of the TLR4/NF-κB pathway proteins in mice was detected by Western Blot. In vitro experiments were conducted to verify the effects of M1 macrophages and S.algae specific LPS on the proliferation,migration and cycle of colorectal tumor cells. Results Compared with the AOM/DSS group,the degree of atypical hyperplasia of intestinal epithelial cells and the level of M1 macrophage increased,the expression of cell proliferation,cyclin and proinflammatory factor also increased,and TLR4/NF-κB pathway was activated after S.algae and its LPS intervention. In vitro studies have also shown that S.algae and its LPS can promote the proliferation,migration and cycle of colorectal tumor cells. Conclusions S.algae specific LPS may promote the occurrence and development of colorectal adenoma through M1 macrophages.