lincRNA-p21在酒精性肠道损伤中的作用

Role of lincRNA-p21 in alcohol-induced intestinal injury

目的探讨基因间长链非编码RNA-p21(lincRNA-p21)在酒精性肠道损伤中的作用。方法将15只C57BL/6Cnc小鼠适应性喂养一周,随机取10只,随机分为lincRNA-p21过表达组和对照组各5只,分别于尾静脉注射lincRNAp21-over-AAV8-U6-GFP病毒、control-AAV8-U6-GFP病毒;以5只Trp53cor1基因敲除C57BL/6小鼠(lincRNA-p21-/-)为突变组,以5只C57BL/6Cnc小鼠作为野生组。各组分别予含5%酒精的液体饲料连续喂养4周,最后3天同时予40%酒精5 g/kg灌胃,建立酒精性损伤模型。模型构建成功后,处死小鼠,留取小肠组织,采用RT-qPCR法检测小肠组织lincRNA-p21表达;HE染色,观察小肠组织病理形态变化;免疫组化法检测小肠组织紧密连接蛋白claudin-1、ZO-1表达;取盲肠内容物,提取其微生物DNA,并进行16S扩增子测序,分析菌群多态性和组成等。结果lincRNA-p21过表达组小肠组织lincRNA-p21相对表达量高于对照组(t=5.31,P<0.05);突变组lincRNA-p21相对表达量低于野生组(t=3.95,P<0.01)。HE染色显示,各组均出现肠道损伤,肠黏膜可见粒细胞、单核细胞浸润。与对照组比较,lincRNA-p21过表达组肠道损伤较重,肠绒毛空泡化增多,肠黏膜细胞结构较紊乱,肠壁水肿和肠壁隐窝损伤较重;与野生组比较,突变组肠绒毛空泡化减少,肠黏膜细胞结构较条理,肠壁水肿和肠壁隐窝损伤较轻。lincRNA-p21过表达组claudin-1、ZO-1相对表达量均低于对照组(t分别为20.84、7.57,P均<0.01);突变组claudin-1、ZO-1相对表达量均高于野生组(t分别为5.53、6.69,P均<0.01)。肠道菌群测序结果显示,lincRNA-p21过表达组与对照组、突变组与野生组肠道优势菌群均为厚壁菌门或拟杆菌门。lincRNA-p21过表达组肠道菌群中放线菌门丰度高于对照组(t=4.21,P<0.01);突变组肠道菌群中蓝藻菌门丰度低于野生组(t=2.62,P<0.05)。KEGG分析发现,lincRNA-p21过表达和基因敲减对酒精暴露小鼠肠道菌群功能的影响涉及氨基酸代谢、脂质代谢、营养物质消化吸收以及细胞生长和死亡等方面。结论lincRNA-p21过表达能够加重酒精性肠道损伤,而敲减lincRNA-p21则可减轻酒精性肠道损伤,其机制可能与增加或减轻肠道屏障损伤以及改变肠道菌群结构有关。

Objective To investigate the role of intergenic long non-coding RNA-p21(lincRNA-p21)in alcoholinduced intestinal injury.Methods C57BL/6Cnc mice were fed adaptively for one week,and we randomly selected 10 mice and randomly divided them into the lincRNA-p21 overexpression group and control group,with 5 mice in each group.The mice in the above two groups were injected with lincRNA-p21-over-AAV8-U6-GFP virus and Control-AAV8-U6-GFP virus through the tail vein,respectively.Five Trp53cor1 knockout C57BL/6 mice(lincRNA-p21-/-)were used as KO group,and five C57BL/6Cnc mice were used as wild control group(WT group).Each group was fed a liquid diet containing 5%alcohol for 4 weeks,and 40%alcohol was given 5 g/kg for the last 3 days to establish the alcohol injury models.After the successful modeling,the mice were killed and the intestinal tissues were retained.The expression of lincRNA-p21 in the intestinal tissues was detected by RT-qPCR.The pathological morphological changes of intestinal tissue were observed by HE staining.The expression levels of claudin-1 and ZO-1 in the intestinal tissues were detected by immunohistochemistry.Microbial DNA was extracted from cecum contents of mice,and 16S amplicon sequencing was performed to analyze the polymorphism and composition of microflora.Results The relative expression level of lincRNA-p21 in intestinal tissues of the overexpression group was higher than that of the control group(t=5.31,P<0.05).The relative expression of lincRNA-p21 in the KO group was lower than that in the WT group(t=3.95,P<0.01).HE staining showed that intestinal injury and infiltration of granulocyte and monocyte in intestinal mucosa were observed in all groups.Compared with the control group,the intestinal injury of lincRNA-p21 overexpression group was more serious,intestinal villi vacuolation increased,intestinal mucosal cell structure was more disordered,intestinal wall edema and intestinal wall recess damage were more serious.Compared with the WT group,intestinal villi vacuolation was reduced in the KO group,intestinal mucosal cell structure was more orderly,intestinal wall edema and intestinal wall recess injury were less severe.The relative expression levels of claudin-1 and ZO-1 in the lincRNA-p21 overexpression group were lower than those in the control group(t=20.84 and 7.57,respectively;both P<0.01).The relative expression levels of claudin-1 and ZO-1 in the KO group were higher than those in the WT group(t=5.53 and 6.69,respectively;both P<0.01).The intestinal flora sequencing results showed that the dominant intestinal flora of the lincRNA-p21 overexpression group and control group,KO group and WT group were firmicutes or bacteroides.The abundance of actinomycetes in intestinal flora of the lincRNA-p21 overexpression group was higher than that of the control group(t=4.21,P<0.01).The abundance of cyanobacteria in the intestinal flora of the KO group was lower than that of the WT group(t=2.62,P<0.05).KEGG analysis showed that the effects of lincRNA-p21 overexpression and gene knockout on intestinal microflora function in alcohol-exposed mice were related to amino acid metabolism,lipid metabolism,nutrient digestion and absorption,and cell growth and death,etc.Conclusions Overexpression of lincRNA-p21 can exacerbate alcoholic intestinal injury,while knockdown of lincRNA-p21 can alleviate alcoholic intestinal injury.The mechanism may be related to increasing intestinal barrier damage and altering intestinal microbiota structure.