The Correlation between Crohn’s Disease and the Expression of IL-32 and Gene Polymorphisms
|Keywords||Crohn’s disease IL-32 expression susceptibility gene CARD15/NOD2 IRGM ATG16L1 NKX2-3 single nucleotide polymorphisms|
Objective:To explore the expression of interleukin-32(IL-32), a novel pro-inflammatory cytokine in the intestinal mucosa of patients with Crohn’s disease (CD). Nowadays, it has been reported that some sequence variants and other multiple replicating loci contribute to Crohn’s disease susceptibility, such as CARD15(NOD2), IRGM, ATG16L1, NKX2-3, etc. We study the correlations of these single nucleotide polymorphisms(SNPs ) associated with Chinese CD, in order that study the pathogenesis of CD in-depth, and provide experimental basis for prevention and treatment of this disease.Methods:The biopsy specimens of clinical diagnosis of CD patients (47 cases) and healthy controls (16 cases) were collected, after pathological examinations, the expressions of IL-32 were detected by immunohistochemistry (IHC) and western blot, the results were used for analysis. To evaluate the relations between gene polymorphisms and CD, peripheral blood from CD patients (32 cases) and healthy controls (30 cases)were extracted, genomic DNA was isolated from leukocyte in the peripheral blood, to estimate the relationships of SNPs about CARD15_rs2066842, IRGM_ rs13361189, ATG16L1_rs2241880 and NKX2-3_rs10883365 mutations associated with CD, matched primers were designed according to the target sequences, the fragments of target sequences were amplified by PCR, after purified, the PCR products were sequencing, and the sequencing results were compared, and make statistical analysis. Results:Compared to controls, the expression of IL-32 in intestinal mucosa with CD patients were up-regulation, and the protein levels of these two groups were significant difference(P﹤0.05). Gene frequencies and genotype frequencies between CD and healthy control groups comparisons showed that: the frequency distributions of the SNPs about CARD15_rs2066842, IRGM_rs13361189, ATG16L1_rs2241880 and NKX2-3 _rs10883365 were no significant difference. It is suggesting that these SNPs of genes variants with Chinese CD patients susceptibility has no correlations.Conclusion:In spite of the pro-inflammatory cytokine IL-32 was expressed in intestinal mocusa of CD patients and controls, the expression levels of this protein in CD was increased, our studies show that IL-32 up-expression could aggravate chronic inflammatory response in CD. The abroad researchers have reported the SNPs about CARD15_rs2066842, IRGM_rs13361189, ATG16L1_rs2241880 and NKX2-3_ rs10883365 associated with the Caucasians or Japanese CD, but we found that the SNPs of these gene sites variants associated with susceptibility of Chinese CD might not be related, and the SNPs variants at most increased the risk of suffering from CD.