The Promoter SNP, but not the Alternative Splicing SNP, is Linked to Multiple Sclerosis Among Jordanian Patients

Association study of promoter polymorphisms of interferon alpha and beta receptor subunit 1 (IFNAR1) gene and therapeutic response to interferon-beta in patients with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease described by inflammatory neuronal losses and resultant failures. The disease could abate by interferon-beta (IFN-β) therapy in MS patients. However, the drug response productivity is changeable between patients, and the accurate mechanism of action of the IFN-β is not obvious. The present study aims to investigate the role of interferon alpha and beta receptor subunit 1 (IFNAR1) promoter polymorphisms towards IFN-β treatment response in MS patients.

METHODS

The subjects herein were separated into either responder (n = 57) or non-responder (n = 43) groups according to IFN-β treatment and Expanded Disability Status Scale score. The Sanger sequencing method was used for genotyping.

RESULTS

Among nearly 64 Single Nucleotide Polymorphisms (SNPs), we found a significant association between the rs2850015 polymorphism and the responders and non-responders to IFN-β treatment in the recessive model of inheritance (P = 0.02). The results also revealed a significant change in the two groups of responders and non-responders to the treatment for rs36158718 as an Insertion/Deletion (INDEL) (P = 0.02). Moreover, bioinformatic analyses predicted a remarkable role for both rs2850015 and rs36158718 related to the changes of binding affinity of transcription factors and alterations in their alleles.

CONCLUSION

The present study results suggest that the genetic heterogeneity in the promoter region of IFNAR1 could affect the response to IFN-β. However, further studies with a larger sample size are needed to further demonstrate this relationship.

Soluble IL-7Rα/sCD127 in Health, Disease, and Its Potential Role as a Therapeutic Agent

Soluble cytokine receptors can influence immune responses by modulating the biological functions of their respective ligands. These effects can be either agonistic or antagonistic and a number of soluble cytokine receptors have been shown to play critical roles in both maintenance of health and disease pathogenesis. Soluble IL-7Ra (sCD127) is one such example. With its impact on the IL-7/CD127 pathway, which is fundamental for the development and homeostasis of T cells, the role of sCD127 in health and disease has been extensively studied in recent years. Within this review, the role of sCD127 in maintaining host immune function is presented. Next, by addressing genetic factors affecting sCD127 expression and the associated levels of sCD127 production, the roles of sCD127 in autoimmune disease, infections and cancer are described. Finally, advances in the field of soluble cytokine therapy and the potential for sCD127 as a biomarker and therapeutic agent are discussed.

Association between IL7 Receptor Alpha (Il7ra) gene rs6897932 polymorphism and the risk of Multiple Sclerosis: A meta-regression and meta-analysis

BACKGROUND

In this systematic review and meta-analysis, we aimed to find a consistent conclusion for the association between the interleukin 7 receptor alpha (IL7RA) gene rs6897932 single nucleotide polymorphism (SNP) and multiple sclerosis (MS) risk.

METHODS

Here, we performed a comprehensive systematic search in PubMed, Scopus, and Web of Science to find relevant studies published before November 2020 investigating the association between rs6897932 SNP and MS risk. In the pooled analysis, we determined the odds ratio (OR) and the corresponding 95% confidence interval (CI) for the association level between rs6897932 SNP and the risk of MS.

RESULTS

In the current meta-analysis 33 case-control studies (30 articles) containing 19351 patients and 21005 healthy controls certify the inclusion criteria. According to the pooled analysis, a statistically significant association of IL7RA gene rs6897932 SNP with MS risk was found across recessive model (OR= 0.84, 95% CI= 0.77-0.92, P< 0.001, FEM), allelic model (OR= 0.91, 95% CI= 0.85-0.99, P= 0. 02, REM), TT vs. CC model (OR= 0.79, 95% CI= 0.67-0.93, P= 0.005, REM). Moreover, the subgroup analysis based on the ethnicity indicated a negative significant association in Europeans; dominant model (OR= 0.88, 95% CI= 0.78-1.01, P= 0.06, REM), recessive model (OR= 0.79, 95% CI= 0.71-0.88, P< 0.001, REM), allelic model (OR= 0.88, 95% CI= 0.81-0.96, P= 0.003, REM), TT vs. CC model (OR= 0.74, 95% CI= 0.61-0.88, P<0.001, REM) models. Nonetheless, no significant association was detected in Asians and Americans.

CONCLUSIONS

IL7RA gene rs6897932 SNP decreases MS susceptibility in overall population and Europeans.

Association Between IL7R Promoter Polymorphisms and Multiple Sclerosis in Turkish Population

Multiple sclerosis (MS) is a chronic progressive neurodegenerative disease that affects myelin fibers within the central nervous system resulting in neurological impairment. Although the etiology of MS is not fully understood, environmental and genetic factors are thought to play important roles. IL7R gene polymorphisms which are associated with several autoimmune diseases have also been implicated as a genetic factor for MS following genome-wide association studies. To further examine this association, we investigated the association between MS and IL7R gene - 449 (A/G), - 504 (T/C), and - 1085 (G/T) promoter polymorphisms in Turkish population. Three hundred sixty-four MS patients and 191 healthy controls were involved in this study. Three polymorphic regions in the promoter of IL7R were identified and these regions were amplified by appropriate primers. The PCR products were digested by PstI enzyme for - 504 (T/C) SNP and HphI enzyme for - 1085 (G/T) and - 449 (A/G) SNPs and genotyping was done based on digested PCR product sizes. Genotype distributions and allele frequencies of - 449 polymorphism did not show any significant association with MS directly (p = 0.120 and p = 0.490, respectively). But the genotypes of IL7R - 449 GA for AOMS and AA for EOMS were a risk factor in according to age of onset (p = 0.002, OR = 4.021, 95% CI = 1.642-9.845). Furthermore, IL7R - 449 A allele was found to be a risk factor for EOMS (p = 0.011, OR = 1.3, 95% CI = 1.107-1.527). Significant association was seen between IL7R - 504 TC heterozygote genotype and MS (p = 0.02, OR = 1.702, 95% CI = 1.169-2.478). The IL7R - 1085 (G/T) polymorphism did not show association with MS; however, the haplotype of ACG may be susceptibility to MS and RRMS (p = 0.035, OR = 1.349, 95% CI = 1.020-1.785, and p = 0.041, OR = 1.368, 95% CI = 1.012-1.850, respectively) and the haplotypes of ACG, ATT, and GTG demonstrate a protective effect in EOMS (p = 0.008, OR = 0.326, 95% CI = 0.136-0.782, p = 0.012 and p = 0.012, OR = 0.462, 95% CI = 0.249-0.859, respectively). RRMS frequency in the Turkish population was decreased and SPMS frequency was strongly increased based on comparison to results from other populations. Furthermore, male patients had an increased frequency of SPMS significantly (p = 0.033, OR = 1.667, 95% CI = 1.036-2.682). In conclusion, this is the first study to show a significant association between the IL7R promoter polymorphisms and the age of onset of MS.

Variants in the IL7RA gene confer susceptibility to multiple sclerosis in Caucasians: evidence based on 9734 cases and 10436 controls

Recently, numerous genome wide association studies (GWAS) and other case-control association studies examining the relationship between interleukin-7 receptor α chain (IL7RA) gene rs3194051, rs987107, rs11567686, and rs11567685 variants and multiple sclerosis (MS) risk have been conducted, but the conclusions have been inconsistent. The main objective of this meta-analysis was to more precisely explore the association of these four IL7RA variants with MS development. Twenty-seven eligible studies involving 9734 cases and 10436 controls were included in the present meta-analysis. Power calculation, publication bias, sensitivity analysis and cumulative meta-analysis were performed to derive a reliable conclusion. Our study indicated three IL7RA loci were significantly associated with increasing MS risk (rs3194051: recessive model: OR = 1.22, 95% CI 1.08–1.38; rs987107: recessive model: OR = 1.44, 95% CI 1.22–1.69; and rs11567686: dominant model: OR = 1.18, 95% CI 1.01–1.37). Additionally, IL7RA rs11567685 variants might not be related to MS development. In all, IL7RA locus polymorphisms could play an important role in the predisposition to MS, which could contribute to a better understanding the pathogenesis of multiple sclerosis.

Interleukin 7 receptor polymorphisms and the risk of multiple sclerosis: A meta-analysis

BACKGROUND

Multiple sclerosis (MS) is considered as the most common chronic inflammatory neurologic disorder diagnosed in young adults. Both environmental and genetic factors may influence risk of MS development. Interleukin 7 receptor (IL7R) is one of the most studied gene polymorphism on MS that may play a possible role in MS development. The most studied polymorphism of IL7R gene is "rs6897932" polymorphism on IL7Rα gene (IL7RA).

METHODS

PubMed, Scopus, and Google scholar databases were searched for all of related studies on the association of IL7RA polymorphism with single nucleotide polymorphism (SNP) ID of "rs6897932" and the risk of MS through August 07, 2015. After exclusion of irrelevant articles, 11 eligible studies were selected, which were analyzed to determine an association between the MS and IL7R T244I polymorphism (rs6897932). For identification of this association, odds ratios (ORs) and 95% confidence interval (95% CI) were calculated. Four models of allelic (T vs. C), co-dominant genotype (TT vs. CC), dominant (TT+CT vs. CC), and recessive genotypes (TT vs. CT+CC) were considered to check the possible role of rs6897932 polymorphism in MS. A sensitivity analysis was conducted to find the reliability of this study. Furthermore, funnel plots were used to evaluate publication bias.

RESULTS

A total of 11 case-control studies were identified through this meta-analysis, which containing 6752 cases and 7349 controls. In overall, the frequency of the C allele was found to be higher in patients with MS compared to healthy controls (75.66% vs. 72.19%). T allele was significantly associated with the decreased risk of MS in a random effect model (T vs. C: OR=0.84, 95% CI=0.77-0.92, P-value <0.001). In the co-dominant, dominant, and recessive genotypes models, a significant association between the IL7R T244I polymorphism and MS risk was demonstrated (TT vs. CC: OR=0.70, 95% CI=0.61-0.80, P-value <0.001; TT+CT vs. CC: OR=0.82, 95% CI=0.73-0.92, P-value <0.001; TT vs. CT+CC: OR=0.76, 95% CI=0.66-0.87, P-value <0.001). Sensitivity analysis revealed that this study is reliable. There was no evidence of publication bias.

CONCLUSION

It was demonstrated that the IL7R T244I polymorphism was associated with susceptibility to MS. However, more well-designed studies with large sample size are needed to validate this association between this single nucleotide polymorphism and MS.