The impact of the rs8005161 polymorphism on G protein-coupled receptor GPR65 (TDAG8) pH-associated activation in intestinal inflammation.

Tcymbarevich, Irina V; Eloranta, Jyrki J; Rossel, Jean-Benoît; Obialo, Nicole; Spalinger, Marianne; Cosin-Roger, Jesus; Lang, Silvia; Kullak-Ublick, Gerd A; Wagner, Carsten A; Scharl, Michael; Seuwen, Klaus; Ruiz, Pedro A; Rogler, Gerhard; de Vallière, Cheryl; Misselwitz, Benjamin (2019). The impact of the rs8005161 polymorphism on G protein-coupled receptor GPR65 (TDAG8) pH-associated activation in intestinal inflammation. BMC gastroenterology, 19(1), p. 2. BioMed Central 10.1186/s12876-018-0922-8

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BACKGROUND

Tissue 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.

METHODS

1138 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.

RESULTS

In 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.

CONCLUSIONS

The 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.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Paediatric Medicine
09 Interdisciplinary Units > Centre for University Continuing Education
04 Faculty of Medicine > Department of Gastro-intestinal, Liver and Lung Disorders (DMLL) > Clinic of Visceral Surgery and Medicine

UniBE Contributor:

Misselwitz, Benjamin

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1471-230X

Publisher:

BioMed Central

Language:

English

Submitter:

Anette van Dorland

Date Deposited:

30 Jan 2019 13:51

Last Modified:

05 Dec 2022 15:24

Publisher DOI:

10.1186/s12876-018-0922-8

PubMed ID:

30616622

Additional Information:

Uni-Be Authors Susanne Schibli, Johannes Spalinger, and Christiane Sokollik are explicitly mentioned as contributors of the Swiss IBD Cohort Study Group.

Uncontrolled Keywords:

Acidic pH CD IBD Inflammatory bowel diseases RhoA UC cAMP pH-sensing

BORIS DOI:

10.7892/boris.123513

URI:

https://boris.unibe.ch/id/eprint/123513

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