Abstract: Objective To investigate how long non-coding RNA(lncRNA)GAS5 regulates Th17/Treg imbalance through targeting miR-155 in celiac disease(CeD). Methods Peripheral blood was collected from 20 CeD patients(CeD group)and 20 healthy individuals without CeD or other autoimmune diseases(healthy group),CD4⁺T cells were isolated from both groups.the expression levels of lncRNA GAS5 and miR-155 in CD4⁺T cells from CeD patients and the control group were dected by qRT-PCR.Flow cytometry was used to analyze the Th17/Treg ratio.Pearson statistical analysis was performed to evaluate the correlation between the expression levels of lncRNA GAS5 and miR-155 with the Th17/Treg ratio in CeD patients.In vitro,CD4⁺T cells from the CeD patients were divided into 7 groups:control group,pcDNA3.1-NC group,pcDNA3.1-GAS5 group,miR-NC group,miR-155-mimics group,pcDNA3.1-GAS5+miR-NC group,and pcDNA3.1-GAS5+miR-155-mimics group.qRT-PCR was used to detect the expression levels of lncRNA GAS5 and miR-155 in each group.Edu staining and Hoest33342 staining was used to detect the proliferation and apoptosis of CD4⁺T cells,respectively.Immunofluorescence staining was used to measure the expression of IL-17 and Foxp3.Flow cytometry was used to detect the proportion of IL-17⁺ and Foxp3⁺ cells in each group. Results Compared to those in the healthy group,the expression level of lncRNA GAS5 in the CeD group was decreased,while the expression level of miR-155 was increased.lncRNA GAS5 was negatively correlated with the Th17/Treg ratio(r=-0.65,P<0.05),and miR-155 was positively correlated with the Th17/Treg ratio(r=0.70,P<0.05).In CD4⁺T cells from the CeD group,the pcDNA3.1-GAS5 group showed increased expression levels of lncRNA GAS5 and Foxp3,increased proliferation rate of CD4⁺T cells,and increased proportion of Foxp3⁺ cells(allP<0.05),while the expression levels of miR-155 and IL-17,the apoptosis rate of CD4⁺T cells,and the proportion of IL-17⁺ cells were decreased(allP<0.05)when compared with those in the pcDNA3.1-NC group.When compared with the miR-NC group,the miR-155-mimics group showed decreased Foxp3 expression level,decreased proliferation rate of CD4⁺T cells,and decreased proportion of Foxp3⁺ cells(allP<0.05),while the expression levels of miR-155 and IL-17,the apoptosis rate of CD4⁺T cells,and the proportion of IL-17⁺ cells were increased(allP<0.05).Compared with the pcDNA3.1-GAS5+miR-NC group,the pcDNA3.1-GAS5 ⁺ miR-155-mimics group showed decreased Foxp3 expression level,decreased proliferation rate of CD4⁺T cells,and decreased proportion of Foxp3⁺ cells(allP<0.05),while the expression levels of miR-155 and IL-17,the apoptosis rate of CD4⁺T cells,and the proportion of IL-17⁺ cells were increased(allP<0.05). Conclusion lncRNA GAS5 regulates Th17/Treg imbalance by targeting miR-155,affecting the proliferation and apoptosis of CD4⁺T cells in CeD patients,thereby influencing IL-17 and Foxp3 expression.This suggests that lncRNA GAS5 may serve as a potential therapeutic target for CeD.

Key words: celiac disease, long non-coding RNA GAS5, microRNA-155, T help type 17 cells, regulatory T cells