Association Between the UBE2Z Rs46522 and TCF7L2 Rs7903146 Polymorphisms with Type 2 Diabetes in South Western Iran
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Association between the UBE2Z rs46522 and TCF7L2 rs7903146 polymorphisms with type 2 diabetes in south western Iran Ali Mohammad Foroughmand1, Sana Shafidelpour1, Merhrnoosh Zakerkish2, Mehdi Pourmehdi Borujeni3 1. Department of Genetics, Faculty of Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran. 2. Department of Endocrinology and Metabolism, Health Research Institute, Diabetes Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 3. Department of Food Hygiene and Quality control, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran. Abstract Background: Transcription factor 7-like 2 Protein (TCF7L2) has a strong role in the pathogenesis of type 2 diabetes melli- tus (T2DM). Association between rs7903146 and T2D risk reported in some of populations. Also many loci such as UBE2Z rs46522 are affecting by TCF7L2 transcription factor have been found associated with T2D. The present study aimed to evaluate association of the SNPs with risk of T2D among our population. Methods: This case-control study was conducted on 150 T2D patients and 150 healthy people (as a control group) in south western Iran. Genotyping was performed by PCR-RFLP. Results: The frequency of genotypes showed no remarkable difference between T2DM patients and control group. The odds ratios of rs7903146 (C/T) poly¬morphism for CC and TC genotypes were 1.9 (95% CI, 0.85 to 4.24; P=0.12) and 0.81 (95% CI, 0.47 to 1.38; P=0.43) compared with the TT genotype, respectively. The odds ratios of rs46522 (C/T) poly¬morphism for TT and TC genotypes were 1.75 (95% CI, 0.86 to 3.59; P=0.13) and 1.38 (95% CI, 0.81to 2.35; P=0.24) compared with the CC genotype, respectively. Conclusion: Our study indicates no association of T2D in south western Iran with the rs7903146 and rs46522 variants. Keywords: Transcription Factor 7-Like 2 Protein, Diabetes Mellitus, Polymorphism. DOI: https://dx.doi.org/10.4314/ahs.v19i3.24 Cite as: Foroughmand AM, Shafidelpour S, Zakerkish M, Borujeni MP. Association between the UBE2Z rs46522 and TCF7L2 rs7903146 polymorphisms with type 2 diabetes in south western Iran. Afri Health Sci. 2019;19(3): 2484-2490. https://dx.doi. org/10.4314/ahs.v19i3.24 Introduction tors have a role in the occurrence and development of Diabetes mellitus type 2 (T2DM) is known as one of the T2DM6,7. most common metabolic diseases. During the five years The single nucleotide polymorphisms (SNPs) of the (from 2008 to 2012), the diabetes prevalence increased transcription factor 7-like 2 gene, on 10q25.3 locus, have with a growth rate of 22.5% for the world and 23.4% for showed strong association with T2DM risk in different- Iran1. The prevalence of diabetes in Iran is reported to populations, however most loci have been reported to be be 9.9 to 13.6%2,3. Obesity, dietary factors and inactive associated with small effect sizes8. The single nucleotide lifestyle are risk factors for T2DM4,5. Also, genetic fac- polymorphisms within the TCF7L2 gene have the stron- gest effect on T2DM9. Also, this gene shows association with the risk of gestational diabetes and PTDM (Post Corresponding author: transplantation diabetes mellitus)10,11. Among the T2DM, Mehrnoosh Zakerkish, the rs7903146(C/T) polymorphism of TCF7L2 gene Health Research Institute, have shown the most significant associations in nearly all Diabetes Research Center, populations and ethnics. However, the frequency of the Ahvaz Jundishapur University rs7903146 risk allele is considerably less in Asian stud- of Medical Sciences, Ahvaz, Iran. ies. Some studies reported no association with T2DM in Email: [email protected] some Asian ethnic populations12,13. African © 2019 Foroughmand et al. Licensee African Health Sciences. This is an Open Access article distributed under the terms of the Creative commons Attribution Health Sciences License (https://creativecommons.org/licenses/BY/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. African Health Sciences Vol 19 Issue 3, September, 2019 2484 TCF7L2 as a transcription factor affects several intercel- the TCF7L2 genoe-wide occupancy behavior study with lular functions. It acts as a member of the Wnt signaling cross referencing GWAS-derived statistics with specific pathway. With ligand banding of Wnt to it's receptor, the data, and analyzing the result, revealed UBE2Z rs46522 Wnt signaling pathway turns on. At the following, β-cat- as a novel type 2 diabetes locus23. To our knowledge no enin interacts with BCL9 and translocate to the nucleus. study has yet concerned the association of this SNP with The association of β-catenin with TCF7L2 in the nucle- T2DM in a case-control study. The aim of this study was us result in the activation of some target genes such as to evaluate the association between the UBE2Z rs46522 proglucagon gene14. TCF7L2 represses the expression of and TCF7L2 rs7903146 variants with T2D in a khuzesta- proglucagon gene in endocrine cells15,16. Recently, it was nian population (south western Iran). clear that disruption of the Wnt signaling pathway could lead to emerging T2DM. Wilfred et al show that the CT/ Materials and methods TT genotypes of SNP rs7903146 are strongly associated Participants with the risk of T2D in two independent cohorts. Their Total sample of this case –control study was 300 subjects investigations on pancreatic islets cell of T2DM cases randomly selected from the Khuzestan provinces situated show the increase of TCF7L2 mRNA levels. Besides, the in the south west of Iran and representative of Arab and study of TCF7L2 expression in pancreatic islets of the non- Arab populations. The T2DM patients group were T allele carriers show a considerable increase in mRNA recognized based on ADA criteria (fasting plasma glucose production of TCF7L2, which is associated with abnor- ≥ 126 mg/dl and /or 2 h plasma glucose ≥ 200 mg/ mal insulin secretion and incretin efficacy17. dl) and consist of 150 individuals (males/females:73/77). The control group too, consist of 150 individuals (males/ Until now two incertins have been identified (GIP and females: 77/73) that were not recognized with T2DM ac- GLP-1)18. GLP-1 is the central player in glucose ho- cording to clinical and laboratory examinations. For both meostasis and insulin secretion. Thus, it is indicated that case and control groups, personal data (age, gender, dia- TCF7L2 genetic variants increase the risk of T2DM by betes family history and the degree of obesity using the altering GLP-1 levels19 and affecting the beta cell prolifer- body mass index (BMI) and clinical data (fasting plasma ation and apoptosis level. The regulation of TCF7L2, the glucose, triglyceride and total cholesterol) were analyzed. effects on the protein level and its outcomes are not per- The rationale behind the minimum age selection was to fectly understood. More investigations are needed to find ensure the absence of silent diabetics within the control out the molecular mechanism which an intronic region in group. TCF7L2 affects pancreatic islet function20. One of the genes affecting TCF7L2, which its associ- DNA genotyping ation with T2DM has recently been found, is UBE2Z A 5 mL blood sample was collected in EDTA containing gene. This gene is located on 17q21.32 locus and includes tubes and stored at -40oC for DNA extraction. Leuko- 6 exons. It has been shown that UBE2Z has a high ex- cyte genomic DNA was extracted from the blood spec- pression level in human tissues, especially in the pancre- imen using salting- out method and was quantified by as. It has a major role in the ubiquitin system21. Ubiquiti- Nano Drop and agarose electrophoresis in order to being nation is the process of binding ubiquitin protein to a used in the polymerase chain reaction (PCR). Genotyp- cellular protein. Ubiquitin conjugating enzyme (E2) has ing was done employing PCR-RFLP method. The TC- a significant role in the ubiquitination process. Unfortu- F7L2 rs7903146 polymorphic site (C/T) was amplified by nately not much information was detected about human M-PCR (in Miss-match primer PCR; a Miss match base in UBE2Z21. However, the polymorphism rs46522 within the third position from 3′ end of forward primer in order the second intron of UBE2Z gene already was found to make restriction site for the restriction enzyme RsaI to have an association with coronary heart disease and was used) using the primer pair 5′ - TTAGAGAGCTA- this association has been confirmed by subsequent stud- AGCACTTTTTAGG TA - 3′( Miss-match forward prim- ies22. Recently Johnson et al, by integrating the data from er) and 5′ - AGA GAT GAA ATG TAG CAG TGA AGT G - 3′ (reverse primer). 2485 African Health Sciences Vol 19 Issue 3, September, 2019 PCR was carried out by the use of a thermal cycler. TC- GAATAGGGC-3´ (reverse). The primers were designed F7L2 primers were designed based on previous study24. employing Allel ID 6. Oligonucleotide primers were pre- PCR cycling conditions included initial denaturation at pared from the Pishgam company for both PCRs. PCR 95°C for 4 minutes, 35 cycles of denaturation at 95°C for conditions were as follows: initial denaturation at 95°C 30 seconds, annealing at 58°C for 30 seconds, extension for 7 min, 35 cycles of denaturation at 95°C for 30 s, at 72°C for 45 seconds, and final extension at 72°C for annealing at 57°C for 40s, extension at 72°C for 25s and 5 minutes. PCR product (201-bp) was verified on 1.5% final extension at 72°C for 10 min. PCR product (342-bp) agarose gel using safe stain (figure 1.A). was verified on 1.5% agarose gel (figure 1.C). The PCR The 201-bp product was digested with 0.8 µl of restric- product was digested with 0.5 µl of Restriction enzyme tion enzyme RsaI for 4 hours at 37°C followed by 3% BseGI (BtScI) at 55°C for 4 hours followed by 2.5 % aga- agarose gel electrophoresis gel.