溶质相关载体26A3基因多态性及其在结肠组织中的表达水平与克罗恩病的关系

Relation between gene polymorphisms and the expression in colonic tissues of solute-linked carrier family 26 member A3 and Crohn＇s disease

目的研究浙江省汉族人群溶质相关载体26A3（SLC26A3）基因多态性及其在结肠组织中的表达水平与CD易感性的关系。方法纳入265例CD患者和566名性别、年龄相匹配的健康对照者，采用SNaPshot技术检测SLC26A3（rs17154444、rs7810937、rs7785539、rs2108225、rs6951457）的等位基因和基因型，并进行连锁不平衡和单倍型分析。选取8例结肠型CD患者和8例性别、年龄相匹配的良性结肠息肉患者（对照），采用免疫组织化学法检测结肠组织中SLC26A3蛋白质的表达水平。统计学方法采用t检验或秩和检验，并以非条件Logistic回归分析SLC26A3基因多态性分布差异及其对CD患者临床病理特征的影响。结果CD组rs2108225、rs7785539、rs6951457的突变等位基因频率分别为53.77%（285/530）、4.72%（25/530）、2.83%（15/530），突变基因型频率分别为76.23%（202/265）、9.43%（25/265）、5.66%（15/265），分别低于对照组的60.95%（690/1 132）、8.13%（92/1 132）、6.10%（69/1 132）和83.92%（475/566）、15.37%（87/566）、11.84%（67/566），差异均有统计学意义（P均〈0.05）；CD组rs17154444、rs7810937的突变等位基因频率分别为10.19%（54/530）、34.91%（185/530），突变基因型频率分别为18.49%（49/265）、56.23%（149/265），与对照组的8.30%（94/1 132）、30.92%（350/1 132）和15.55%（88/566）、51.77%（293/566）比较，差异均无统计学意义（P均〉0.05）。回肠末段型CD患者rs2108225突变等位基因G的频率为47.89%（91/190），突变基因型AG＋GG的频率为65.26%（62/95），分别低于结肠型的61.62%（122/198）和85.86%（85/99），差异均有统计学意义（P均〈0.012 5）。rs7810937、rs7785539、rs2108225彼此紧密连锁。CD组单倍型AGG和ACA的频率分别为53.96%（286/530）和4.34%（23/530），分别低于对照组的60.07%（680/1 132）和7.51%（85/1 132），差异均有统计学意义（χ^2＝5.534，P＝0.019；χ^2＝5.967，P＝0.015）；CD组单倍型AGA的频率为8.30%（44/530），高于对照组的1.15%（13/1 132），差异有统计学意义（χ^2＝7.793，P〈0.01）。8例结肠型CD患者结肠组织SLC26A3蛋白质的表达水平为0.19±0.07，低于良性结肠息肉患者的0.26±0.03，差异有统计学意义（t＝2.55，P＝0.023）。携带rs2108225基因型GG和AG的患者结肠组织SLC26A3蛋白质的表达水平分别为0.19±0.03和0.10±0.01，均低于基因型AA携带者的0.26±0.02，差异均有统计学意义（t＝3.19，P＝0.033; t＝9.06，P＝0.003）。结论SLC26A3 rs2108225、rs7785539和rs6951457基因多态性及其构建的单倍型与CD易感性相关。rs2108225基因多态性能影响结肠组织中SLC26A3的蛋白质表达水平。

Objective To explore the relation between genetic polymorphisms and the expression in colonic tissues of solute-linked carrier family 26 member A3 （SLC26A3） and susceptibility of Crohn＇s disease （CD） in Han population of Zhejiang Province. Methods A total of 265 CD patients and 566 gender- and age- matched healthy individuals were enrolled. Alleles and genotypes of SLC26A3 （rs17154444, rs7810937, rs7785539, rs2108225, rs6951457） were examined by SNaPshot. The linkage disequilibrium （LD） and haplotype were also analyzed. Eight patients with colonic CD and eight gender- and age- matched patients with benign colonic polyps （control group） were selected. The expression level of SLC26A3 protein in the colonic tissue was detected by immunohistochemistry. T test and rank-sum test were performed for statistical analysis. Unconditional Logistic regression analysis was used to analyze the distributions of SLC26A3 polymorphisms and their effects on the clinicopathological features of CD patients. Results The frequencies of mutant allele of rs2108225, rs7785539 and rs6951457 of the CD group were 53.77% （285/530）, 4.72% （25/530） and 2.83% （15/530）, and the frequencies of mutant genotype were 76.23%（202/265）, 9.43%（25/265） and 5.66% （15/265）, which were lower than those of the control group （60.95%, 690/1 1323 8.13%, 92/1 1323 6.10%, 69/1 132; 83.92%, 475/566; 15.37 %, 87/566 and 11.84%, 67/566）, and the differences were statistically significant （all P〈0. 05）. The frequencies of mutant allele of rs17154444 and rs7810937 of the CD group were 10. 19% （54/530） and 34.91%（185/530）, and the frequencies of mutant genotype were 18.49% （49/265） and 56.23%（149/ 265）, compared with those of the control group （8.30%, 94/1 132% 30.92%, 350/1 132;15.55%, 88/ 566 and 51.77%, 293/566）, the differences were not statistically significant （all P〉0. 05）. The frequency of mutant allele G of rs2108225 in patients with ileal CD was 47.89% （91/190）, and the frequency of mutant genotype AG＋GG was 65. 26% （62/95）, which were both lower than those of colonic CD （61. 62%, 122/198 and 85.86%, 85/99）, and the differences were statistically significant （both P〈0. 012 5）. rs7810937, rs7785539 and rs2108225 were in a strong linkage disequilibrium. The frequencies of haplotypes AGG and ACA of the CD group were 53.96% （286/530） and 4.34% （23/530）, which were lower than those of the control group （60.07%, 680/1 132 and 7.51%, 85/1 132）, and the differences were statistically significant （χ^2=5. 534, P〈0. 019; χ^2=5. 967, P=0. 015）. And the frequency of haplotype AGA of the CD group was 8.30% （44/530）, which was higher than that of the control group （1.15%, 13/1 132）, and the difference was statistically significant （X2 = 7. 793, P〈0.01）. Furthermore, the expression level of SLC26A3 protein in colonic tissues of eight colonic CD patients was 0.19±0. 07, which was lower than that of patients with benign colonic polyps （0. 26 ± 0. 03）, and the difference was statistically significant （t=2.55, P=0. 023）. In addition, the expression levels of SLC26A3 protein in patients carrying genotype GG or AG of rs2108225 were 0.19±0.03 and 0.10±0.01, respectively, which were lower than that of patients carrying genotype AA （0.26 ±0.02）, and the differences were statistically significant （t=3. 19, P=0. 033; t=9. 06, P=0. 003）. Conclusions The genetic polymorphisms and their haplotypes of SLC26A3 （rs7785539, rs2108225 and rs6951457） are associated with the susceptibility of CD, and SLC26A3 （rs2108225） polymorphism may affect the expression level of SLC26A3 protein in the colonic tissues.