Genetic variation and significant association of polymorphism rs7700944 G>A of TIM-4 gene with rheumatoid arthritis susceptibility in Chinese Han and Hui populations

Novel Roles of the Tim Family in Immune Regulation and Autoimmune Diseases

T cell Ig and mucin domain (Tim) protein family members were identified to be important regulators of the immune response. As their name indicates, Tim proteins were originally considered a T cell-specific markers, and they mainly regulate the responses of T helper cells. However, accumulating evidence indicates that Tims are also expressed on antigen-presenting cells (APCs), such as monocytes, macrophages, dendritic cells (DCs) and B cells, and even plays various roles in natural killer cells (NKs) and mast cells. In recent years, the expression and function of Tims on different cells and the identification of new ligands for the Tim family have suggested that the Tim family plays a crucial role in immune regulation. In addition, the relationship between Tim family gene polymorphisms and susceptibility to several autoimmune diseases has expanded our knowledge of the role of Tim proteins in immune regulation. In this review, we discuss how the Tim family affects immunomodulatory function and the potential role of the Tim family in typical autoimmune diseases, including multiple sclerosis (MS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and type 1 diabetes (T1D). A deeper understanding of the immunoregulatory mechanism of the Tim family might provide new insights into the clinical diagnosis and treatment of autoimmune diseases.

Correlations Between TIMD-4 Gene Variants and the Risk and Clinical Features of Rheumatoid Arthritis in a Chinese Population

Introduction

T-cell immunoglobulin and mucin domain-4 (TIMD-4) are likely to impact autoimmune diseases (e.g., rheumatoid arthritis (RA)). It is hypothesized here that TIMD-4 gene polymorphism is likely to display a correlation with the RA risk.

Methods

For examining the effect exerted by TIMD-4 genetic variant in the RA risk, a case–control study containing 379 RA cases and 432 healthy control groups in Chinese population was performed. This study conducted genotyping with the use of a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ Kit. Blood serum conditions of TIMD-4 in RA cases and matched control groups were measured by enzyme-connected immunosorbent assay (ELISA).

Results

Our results demonstrated that the TIMD-4 rs7700944 polymorphism could increase the RA risk in Chinese population. According to stratification analyzing processes, the TIMD-4 rs7700944 polymorphism displayed the correlation to the elevated RA risk in the females, smokers and cases aged ≥55 years. Cross-over analyses also indicated that the combined effect of smoking or drinking and GA genotype of rs7700944 locus contributed to an elevated risk of RA. In addition, the TIMD-4 rs7700944 polymorphism was also related to RA cases with DAS ≥ 3.20, ESR ≥25.00 mm/h and positive anti-ccp. Moreover, compared with the control groups, the average expression level of TIMD-4 in the serum of RA cases was apparently increased.

Conclusion

In conclusion, the TIMD-4 rs7700944 polymorphism may increase the sensitivity to RA in Chinese population.

Tim-4 in Health and Disease: Friend or Foe?

T-cell immunoglobulin and mucin domain containing 4 (Tim-4) is a phosphatidylserine receptor and is selectively expressed on antigen presenting cells. Recently, Tim-4 was reported to be expressed on iNKT cells, B1 cells, and tumor cells, suggesting it has multiple biological functions. In this review, we mainly summarize the expression and regulation of Tim-4 in immune cells including T cells, macrophages, dendritic cells, NKT cells, B cells, and mast cells. The expression of Tim-4 in these cells implies that Tim-4 might participate in immune related diseases. Emerging evidence emphasizes a substantial role for Tim-4 in maintaining homeostasis by regulating various immune responses, including viral infection, allergy, autoimmunity, and tumor immunity. Here, we collectively evaluated the role of Tim-4 in health and diseases. This summary will be extremely useful to fully understand the function of Tim-4 in the pathogenesis of immune related diseases, which would provide novel clues for the diagnosis and treatment of diseases.

TIM family gene polymorphism and susceptibility to rheumatoid arthritis: Systematic review and meta-analysis

BACKGROUND

TIM-family proteins are expressed on different immune cells such as dendritic cells, macrophages, type 1 and 2 T helper (Th) cells. Therefore, they have the ability to contribute to the various intracellular signals and immune responses, importantly the regulation of Th1 and Th17 cell differentiation, which plays a remarked role in fight against inflammatory and autoimmune diseases. Association of TIM family gene polymorphisms with rheumatoid arthritis (RA) has been frequently investigated. The findings however are not entirely consistent. Therefore, we carried out the present meta-analysis to examine the association between RA and the following TIM family gene polymorphisms: rs41297579, rs1036199, rs10515746, and rs7700944.

METHODS

A systematic search of Scopus, PubMed, and Web of Science databases was conducted through December 2018. Combined odds ratios (OR) with their corresponding 95% confidence intervals (CI) were calculated under different possible genetic models.

RESULTS

A total of eight case-control studies were included in the present meta-analysis. The results demonstrated significant association of RA with TIM-3 rs1036199 polymorphism under dominant (OR, 1.93, 95% CI, 1.43-2.61) and allelic models (OR, 1.74, 95% CI, 1.31-2.30). None of the other examined polymorphisms indicated significant association with RA.

CONCLUSIONS

The present meta-analysis revealed that the TIM-3 rs1036199 polymorphism might confer susceptibility to RA. Further studies are required to reassert our findings.

TIM-3 rs1036199 polymorphism increases susceptibility to autoimmune diseases: evidence based on 4200 subjects

Conflicting results have been reported regarding differing studies on the association between T-cell immunoglobulin and mucin domain 3 polymorphisms and autoimmune disease. The purpose of the present study was to evaluate the association of TIM-3 rs1036199 (4259 G/T) polymorphism with autoimmune disease susceptibility. A meta-analysis was performed to obtain a more precise evaluation of the association. Ten eligible studies were retrieved by searching PubMed, Embase and Web of Science databases, and statistical analyses were performed using STATA software. The pooled results indicated that TIM-3 rs1036199 polymorphism was significantly associated with an increased risk of overall autoimmune disease in allele comparison (G versus T: OR = 1.59, 95%CI: 1.17-2.17) and heterozygous comparison (GT versus TT: OR = 1.68, 95%CI: 1.37-2.06). Subgroup analyses based on disease type demonstrated that TIM-3 rs1036199 polymorphism was associated with an increased risk of rheumatic arthritis (G versus T: OR = 1.88, 95%CI: 1.45-2.44; GT versus TT: OR = 2.02, 95%CI: 1.53-2.65), especially in Asian populations.

Association Study between Polycystic Ovarian Syndrome and the Susceptibility Genes Polymorphisms in Hui Chinese Women

Introduction

Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders. Evidence of familial aggregation analysis and different clinical traits among different regions and ethnicities indicated that the pathogenesis of PCOS is associated with multiple genetic and environmental factors. Our previous research had identified three susceptibility loci (rs2479106, DENND1A; rs13405728, LHCGR; rs13429458, THADA) for PCOS in Han Chinese women. The overall aim of this study was to investigate the relationship between three susceptibility gene polymorphisms and PCOS in Hui ethnic women.

Methods

151 patients with PCOS (case group) and 99 healthy women (control group) were recruited from the Reproductive Medicine Center of the General Hospital of Ningxia Medical University. Clinical data and serum hormone characteristics of case and control groups were collected and analyzed. The three susceptibility single-nucleotide polymorphisms have been replicated in both case and control groups. Gene polymorphisms were detected by direct sequencing after polymerase chain reaction.

Results

The Body Mass Index, LH, LH/FSH ratio and total testosterone were significantly elevated in PCOS patients compared to control group (P<0.05). The frequencies of genotype and allele in rs13405728 were significantly different between the PCOS and the control groups (P<0.05). Of the SNP rs13405728, the PCOS cases with TT genotype stayed at a higher level of total testosterone, TG and LDL than those with the CC and CT genotypes. In contrary, there was no statistical difference between the two groups for SNP rs13429458 and rs2479106 (P>0.05).

Conclusion

The present study suggested that the SNP rs13405728 in the LHCGR gene was associated with PCOS in Hui ethnic women, and its TT genotype characterized with higher level of TT, TG and LDL.

TIM-1 rs41297579 G>A (-1454) and TIM-4 rs7700944 gene polymorphisms as possible risk factor for rheumatoid arthritis: relation to activity and severity

This study was aimed to evaluate the impact of both TIM-1 rs41297579 G>A (-1454) and TIM-4 rs7700944 polymorphisms on susceptibility to rheumatoid arthritis (RA) in a cohort of Egyptian population and to evaluate for the first time their relation to activity, severity, disease-related disability and erosion. TIM-1 rs41297579 G>A (-1454) and TIM-4 rs7700944 gene polymorphisms were typed by RFLP for 128 patients with RA and 125 healthy controls. The A allele, A-containing genotypes (GA and AA) of the TIM-4 and GA haplotype were present with significant higher frequency in patients with RA than healthy controls (Pc  < 0.001). These findings suggest that the A allele, A-containing genotypes (GA and AA) and GA haplotype may be a susceptibility risk factor for RA [OR = 5.83 (3.6-9.4), OR = 9.41 (5.0-17.6) and OR = 4.21 (1.07-19.2), respectively]. No associations were found between TIM genotypes and disease activity, severity or presence of erosion. However, the RA patients with GA genotype of TIM-4 have higher grade of rheumatoid factor (RF) positivity (P = 0.018), and have worse disease-related disability (P = 0.007) and worse pain (0.025). TIM-4 rs7700944 and not TIM-1 rs41297579 G>A (-1454) is associated with RA in the present cohort of Egyptian and may be a risk factor for development of RA in Egyptian. Both SNPs have no effect on disease activity, severity or erosion. However, TIM-4 GA genotype is associated with higher grade of RF positivity and worse disease-related disability and pain.

Tim-3 polymorphism downregulates gene expression and is involved in the susceptibility to ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disorder primarily affecting the sacroiliac joints and the spine. T-cell immunoglobulin- and mucin-domain-containing molecule 3 (TIM-3) has been established as a negative regulatory molecule that plays a critical role in controlling inflammation. Studies have shown that polymorphisms in TIM-3 gene may be associated with inflammatory diseases. The current study investigated the association between polymorphisms in the TIM-3 gene and susceptibility to AS, and it examined the effects of these polymorphisms on gene expression. Two polymorphisms in TIM-3 -574G/T and +4259T/G polymorphisms were identified by polymerase chain reaction-restriction fragment length polymorphism in 282 AS patients and 298 healthy controls. Results showed that frequency of the TIM-3 -574GT genotype was significantly increased in cases than in controls (Odd ratio [OR]=2.50, 95% confidence interval [CI]: 1.39-4.48, p=0.002). Similarly, TIM-3 -574T allele revealed a positive association with the disease (OR=2.39, p=0.002). The TIM-3 +4259T/G polymorphism did not show any correlation with AS. We further evaluated TIM-3 mRNA and protein levels in CD4(+) T cells, CD8(+) T cells, and monocytes from subjects carrying different TIM-3 genotypes. Results revealed that subjects carrying polymorphic -574GT genotype had significantly lower TIM-3 mRNA and protein levels in CD4(+) T cells, CD8(+) T cells, and monocytes than those with wild-type GG genotype. These data suggest that TIM-3 polymorphism is associated with increased susceptibility to AS possibly by downregulating gene expression.

Genetic association of rs1800780 (A→G) polymorphism of the eNOS gene with susceptibility to essential hypertension in a Chinese Han population

To investigate the association of eNOS gene polymorphism with essential hypertension in the Chinese Han population, we examined polymorphisms of the rs2070744 (T→C), rs1800780 (A→G), and rs3918181 (A→G) loci. The results demonstrated that the genotypic frequency at the rs1800780 (A→G) locus was significantly different between patients with essential hypertension and the control cohorts (P < 0.05); while genotypic frequencies and allelic frequencies at rs2070744 (T→C) and rs3918181 (A→G) loci had no statistical difference between the patient group and controls (P > 0.05). In addition, haplotype analysis found a statistically significant difference for haplotype TGA, with OR (95% CI) of 1.549 (1.116-2.150) (P < 0.05). These findings suggest that polymorphism of rs1800780 (A→G) in the eNOS gene may be one of the most important genetic factors associated with essential hypertension susceptibility, and those who have haplotype TGA may be at risk to develop essential hypertension.