ABSTRACT
Objective To explore the role of interleukin (IL)-38 in inhibiting inflammatory bowel disease (IBD) in children and to investigate the potential molecular mechanisms.Methods From January 2014 to October 2017,67 patients with ulcerative colitis (UC) and 115 patients with Crohn's disease (CD)admitted to Wuhan Children's Hospital were recruited,and 40 individuals with normal endoscopic findings were selected as control.Serum levels of IL-38 of IBD patients and healthy control were determined by enzyme-linked immunosorbent assay (ELISA).Immunohistochemical staining (IHC) was used to detect the expression level of IL-38,nuclear factor κB (NF-κB),phosphorylated signal transduction and activator of transcription 3 (p-STAT3),C-reaction protein (CRP) and erythrocyte sedimentation rate (ESR) in the intestinal mucosa of IBD patients and healthy controls.The extent of disease,therapeutic agents and disease activity scores (Mayo score system for UC patients,Crohn's disease activity index (CDAI) for CD patients) were evaluated.IL-38-C57BL/6 transgenic mice model was established,and dextran sulfate sodium was used to induce IBD mice model.The intestinal inflammation levels were compared between the wild type IBD mice and IL-38 transgenic IBD mice.The levels of IL-38,NF-κB and p-STAT3 in intestinal mucosa of mice of different groups were determined by IHC.The ratio of CD4 + IL-17 + T helper (Th) 17 cells in peripheral blood of mice of different groups was detected by flow cytometry.Independent sample t test,chi square test and Pearson correlation were performed for statistical analysis.Results The results of ELISA showed that the serum levels of IL-38 of UC and CD patients were (6.1 ± 1.9) ng/L and (9.8 ±2.1) ng/L,respectively,which both were lower than that of healthy controls ((16.4 ± 2.7) ng/L),and the differences were statistically significant (t =23.107 and 15.853,both P ＜ 0.05).The results of IHC indicated that the levels of IL-38 in the intestinal mucosal tissues of UC and CD patients were 0.04 ± 0.01 and 0.03 ± 0.01,respectively,which were both lower than that of healthy controls (0.18 ± 0.02),and the differences were statistically significant (t =48.186 and 69.443,both P ＜ 0.05).The levels of NF-κB and p-STAT3 of UC and CD patients were 0.150 ± 0.030,0.160 ± 0.040 and 0.130 ±0.030,0.110 ±0.010,which were all higher than those of healthy controls (0.020 ±0.003 and 0.010 ± 0.002),and the differences were statistically significant (tUC =27.273 and 23.078,tCD =23.657 and 62.684;all P ＜ 0.05).The number of patients with disease at active phase,CRP level,ESR and disease activity scores of UC and CD patients with low IL-38 expression were all significantly higher than those of patients with high IL-38 expression (x2UC =11.552,tUC =7.118,8.991 and 7.086;x2CD =5.675,tCD =9.559,9.358 and 11.268;all P ＜ 0.05).The results of Pearson correlation analysis demonstrated that the level of IL-38 in the intestinal mucosal tissue of UC patients was negatively correlated with CRP,ESR and Mayo scores (r =-0.291,-0.672 and-0.639;all P ＜ 0.05).And the level of IL-38 in the intestinal mucosal tissue of CD patients was negatively correlated withCRP,ESRandCDAI (r=-0.559,-0.471 and-0.353;allP＜0.05).The IHC results showed that the levels of NF-κB and p-STAT3 of IL-38 transgenic IBD mice were lower than those of wild type IBD mice (0.14±0.02 vs.0.32 ±0.06,0.12 ±0.02 vs.0.44 ±0.07),and the differences were statistically significant (t =6.971 and 10.767,both P ＜ 0.05).The results of flow cytometry showed that the ratio of CD4 + IL.-17+ Th17 cells in the peripheral blood of IL-38 transgenic IBD mice was lower than that of wild type IBD mice (0.030±0.006 vs.0.280 ±0.050),and the difference was statistically significant (t =12.160,P ＜0.05).Conclusions The expression level of IL-38 significantly decreases in the intestinal mucosal tissues of IBD patients,while the level of NF-κB and p-STAT3 significantly increases.IL-38 may inhibit IBD by regulating NF-κB and p-STAT3 signaling pathway to alleviate intestinal immune reaction.
ABSTRACT
Interleukin ( IL) -38 is the most recently discovered cytokine, which is the tenth member of IL-1 cytokine family. IL-38 shares a high homology with IL-1 receptor antagonist ( IL-1 Ra) and IL-36 Ra. IL-36 R is the specific receptor of IL-38 which is the partial receptor antagonist of IL-36. Now, research has shown that IL-38 not only had relationship with intracellular infection and inflammation, but also with many clinical diseases such as autoimmune diseases, osteoarthritis, tumor and cardiopulmonary diseases. However, the molecular immune regulation mechanism of IL-38 is complicated, involving specific receptor recruitment, apoptosis mediated phagocyte regulation, regulation of Th17 cell differentiation and many other processes. It also provides several new clues to the treatment of diseases. IL-38 is a new cytokine research hot spot with extensive application prospects and need deep exploration.
ABSTRACT
Objective To investigate the effect of interleukin (IL)-38 on T helper 17 (Th17) cells in patients with rheumatoid arthritis (RA).Methods Total RNA were extracted and reverse transcribed into complementary DNA.Real-time polymerase chain reaction (PCR) technique was used to determine the gene expression of IL-38 at transcription level.Enzyme linked immune sorbent assay (ELISA) was used to detect the levels of IL-38 and IL-17 in peripheral blood.The percentage of peripheral blood Th17 cells was determined by Flow cytometry.Statistical analysis was conducted with t-test and Mann-Whitney U rank test.Results ① IL-38 mRNA expression from RA patients (2.9±4.0) was significantly reduced as compared with normal controls (5.8±3.6),(Z=-1.28,P＜0.05).IL-38 protein expression from RA patients (0.44±0.03) was lower than healthy controls (0.72±0.58),(Z=-1.59,P＜0.05).② The number of Th17 cells from RA patients (11.7±3.2) increased compared with healthy controls (7.9±2.3),(Z=-1.98,P＜0.05).The counts of Th17 cells from RA patients was negatively correlated with IL-38 (r=-0.38,P＜0.05).③ The level of peripheral blood IL-17 in RA (64±52) was significantly higher than normal controls (35±8),(Z=-2.17,P＜0.05).The level of IL-17 in RA was negatively correlated with IL-38 (r=-0.31,P＜0.05).④ IL-38 caused a significant decrease in the number of Th17 cells from RA patients (5.7±1.2) compared with untreated cells (7.9±2.3),(Z=-1.57,P＜0.05).Conclusion The decrease of IL-38 level in RA patients has resulted in the excessive activation of Th17 cells,which triggers the occurrence of RA.