肠上皮脂解刺激脂蛋白受体减轻葡聚糖硫酸钠诱导的小鼠结肠炎

Lipolysis-stimulated lipoprotein receptor in intestinal epithelium attenuates dextran sodium sulfate-induced colitis in mice

目的:探索脂解刺激脂蛋白受体(lipolysis-stimulated lipoprotein receptor,LSR)在葡聚糖硫酸钠(dextran sodium sulfate,DSS)诱导的结肠炎小鼠中的表达变化,以及肠上皮Lsr特异性敲除及过表达对结肠炎小鼠肠道炎症的影响。方法:C57BL/6J小鼠饮水中加入浓度为3%(w/v)的DSS,自由饮用6 d诱导小鼠结肠炎模型;实验结束后,通过RNA-seq对对照组和实验组中差异表达的基因进行筛选,通过RT-qPCR、Western blot和免疫荧光染色的方法检测LSR表达变化。接下来,通过Cre-loxP系统构建肠上皮Lsr特异性敲除小鼠,建立DSS诱导的结肠炎模型,检测体重变化、疾病活动度指数(disease activity index,DAI)评分、结肠长度并进行HE染色来评估小鼠肠炎症状;同时,通过ELISA检测血清中促炎细胞因子肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)、IL-6和IL-18水平;免疫荧光染色检测结肠组织中性粒细胞和巨噬细胞浸润情况;PAS染色观察杯状细胞数量。最后,腹腔注射腺相关病毒(AAV-Lsr)构建LSR过表达小鼠,确定LSR过表达成功后,通过上述方法诱导小鼠结肠炎模型后观察肠道炎症情况。结果:LSR在DSS诱导的结肠炎小鼠中表达下调,同时,肠上皮Lsr特异性敲除小鼠对DSS诱导的结肠炎的易感性增加,表现为体重显著减轻(P<0.05),DAI得分显著升高(P<0.01),结肠长度显著缩短(P<0.05),病理损伤加重,促炎细胞因子TNF-α(P<0.05)、IL-1β(P<0.01)、IL-6(P<0.05)和IL-18(P<0.01)水平显著升高,炎症细胞浸润增加,结肠杯状细胞数量减少。此外,LSR过表达显著减轻DSS诱导的结肠炎小鼠肠道炎症。结论:LSR在DSS诱导的结肠炎小鼠中表达降低,LSR缺失加重DSS诱导的结肠炎小鼠的肠道炎症,AAV介导LSR过表达能减轻DSS诱导的结肠炎小鼠的肠道炎症。

AIM:To investigate the expression of lipolysis-stimulated lipoprotein receptor(LSR)in dextran sodium sulfate(DSS)-induced colitis mice,and the effects of Lsr-specific knockout and overexpression in intestinal epithe-lium on intestinal inflammation in colitis mice.METHODS:C57BL/6J mice were administered 3%(w/v)DSS in drink-ing water for 6 days to induce colitis.Following the experiment,RNA-seq was employed to screen differentially expressed genes between the control group and experimental group.Changes in LSR expression were assessed using RT-qPCR,Western blot,and immunofluorescence staining.Intestinal epithelial Lsr-specific knockout mice were generated using the Cre-loxP system and subjected to DSS-induced colitis.Colitis severity was evaluated through changes in body weight,dis-ease activity index(DAI)score,colon length,and hematoxylin-eosin(HE)staining.Additionally,serum levels of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6,and IL-18 were measured via ELISA.Immunofluorescence staining was utilized to detect neutrophil and macrophage infiltration in colon tissues,while periodic acid-Schiff(PAS)staining was used to observe goblet cell numbers.Furthermore,adeno-associated virus(AAV-Lsr)was intraperitoneally injected to achieve LSR overexpression.Successful LSR overexpression was confirmed,and a DSS-induced colitis model was established using similar methods to observe intestinal inflammation.RESULTS:Results showed decreased LSR ex-pression in DSS-induced colitis mice.Intestinal epithelial Lsr-specific knockout mice exhibited increased susceptibility to DSS-induced colitis,evidenced by significantly reduced body weight(P<0.05),increased DAI(P<0.01),shortened co-lon length(P<0.05),and exacerbated pathological injury.Levels of pro-inflammatory cytokines TNF-α(P<0.05),IL-1β(P<0.01),IL-6(P<0.05),and IL-18(P<0.01)were significantly elevated,along with increased inflammatory cell infiltration and reduced goblet cell numbers in the colon.Conversely,LSR overexpression via AAV significantly alleviated intestinal inflammation in DSS-induced colitis mice.CONCLUSION:In conclusion,LSR expression decreased in DSS-induced colitis mice,and its loss exacerbated intestinal inflammation in this model.AAV-mediated LSR overexpression provided therapeutic relief from intestinal inflammation in DSS-induced colitis mice.