The impact of the rs8005161 polymorphism on G protein-coupled receptor GPR65 (TDAG8) pH-associated activation in intestinal inflammation
The impact of the rs8005161 polymorphism on G protein-coupled receptor GPR65 (TDAG8) pH-associated activation in intestinal inflammation
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DOI：
10.1186/s12876-018-0922-8
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发表时间：
2019-01-07
影响因子：
2.4
通讯作者：
Zimmermann, Dorothee
中科院分区：
文献类型：
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作者：
Tcymbarevich, Irina V.;Eloranta, Jyrki J.;Zimmermann, Dorothee
炎症性肠病（IBD）的组织炎症与局部ph降低有关。最近有报道称，编码g蛋白偶联受体65 （GPR65）的基因是IBD的一个遗传危险因素。在细胞外酸化反应中，质子激活GPR65刺激cAMP和Rho信号通路。我们的目的是分析GPR65相关单核苷酸多态性（SNP） rs8005161的临床和功能相关性。方法采用Taqman SNP法对IBD患者和健康志愿者中1138人的GPR65 （rs8005161、rs3742704）和半乳糖神经酰胺酶（rs1805078）相关SNP进行基因分型。来自瑞士IBD队列研究（SIBDC）的2300例患者通过基于质谱的SNP基因分型对rs8005161进行了基因分型。从携带rs8005161基因的SIBDC中招募IBD患者TT、CT、CC和非IBD对照（CC）进行功能研究。从血液样本中分离出人CD14+细胞，并对其进行细胞外酸性pH变化，测量cAMP积累和RhoA激活。结果在我们的混合队列中，而不是在SIBDC患者中，次要变异rs8005161与UC显著相关。在SIBDC患者中，我们观察到携带rs8005161-TT和rs8005161-CT等位基因的患者疾病严重程度增加的一致趋势。当细胞外pH值发生酸性变化时，IBD （TT、CT、WT/CC）和非IBD （WT/CC）基因型携带者之间cAMP生成的pH相关激活没有显著差异。然而，我们观察到，无论rs8005161等位基因如何，IBD患者在细胞外酸性pH值改变后，RhoA激活显著受损。结论rs8005161的T等位基因可能导致IBD患者病程加重。来自IBD患者的人单核细胞在酸性pH值转移时显示出与pH相关的RhoA激活受损。
BackgroundTissue inflammation in inflammatory bowel diseases (IBD) is associated with a decrease in local pH. The gene encoding G-protein-coupled receptor 65 (GPR65) has recently been reported to be a genetic risk factor for IBD. In response to extracellular acidification, proton activation of GPR65 stimulates cAMP and Rho signalling pathways. We aimed to analyse the clinical and functional relevance of the GPR65 associated single nucleotide polymorphism (SNP) rs8005161.Methods1138 individuals from a mixed cohort of IBD patients and healthy volunteers were genotyped for SNPs associated with GPR65 (rs8005161, rs3742704) and galactosylceramidase (rs1805078) by Taqman SNP assays. 2300 patients from the Swiss IBD Cohort Study (SIBDC) were genotyped for rs8005161 by mass spectrometry based SNP genotyping. IBD patients from the SIBDC carrying rs8005161 TT, CT, CC and non-IBD controls (CC) were recruited for functional studies. Human CD14+ cells were isolated from blood samples and subjected to an extracellular acidic pH shift, cAMP accumulation and RhoA activation were measured.ResultsIn our mixed cohort, but not in SIBDC patients, the minor variant rs8005161 was significantly associated with UC. In SIBDC patients, we observed a consistent trend in increased disease severity in patients carrying the rs8005161-TT and rs8005161-CT alleles. No significant differences were observed in the pH associated activation of cAMP production between IBD (TT, CT, WT/CC) and non-IBD (WT/CC) genotype carriers upon an acidic extracellular pH shift. However, we observed significantly impaired RhoA activation after an extracellular acidic pH shift in IBD patients, irrespective of the rs8005161 allele.ConclusionsThe T allele of rs8005161 might confer a more severe disease course in IBD patients. Human monocytes from IBD patients showed impaired pH associated RhoA activation upon an acidic pH shift.