A functional polymorphism in the TIM-1 gene is associated with asthma in a Chinese Han 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.

Associations of TIM-1 Genetic Polymorphisms with Asthma: A Meta-analysis

PURPOSE

Recently, the roles of TIM-1 genetic polymorphisms in asthma have been extensively studied, with conflicting results. Therefore, we performed the present meta-analysis to better assess potential associations of TIM-1 genetic polymorphisms with asthma.

METHODS

Eligible articles were searched in PubMed, Medline, EMBASE, Google Scholar, and CNKI up to December 2016. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to detect any potential associations between TIM-1 genetic polymorphisms and asthma.

RESULTS

A total of 12 articles including 3120 asthma patients and 2825 control subjects were analyzed. The overall and subgroup analyses revealed that TIM-1-416G>C single nucleotide polymorphism was significantly associated with asthma for the Asian population in the codominant (G/G vs. G/C, p = 0.0003, OR 1.86, 95% CI 1.33-2.60) and dominant (G/G vs. G/C + C/C, p < 0.0001, OR 1.94, 95% CI 1.40-2.69) genetic models. Nevertheless, we failed to detect any significant associations between TIM-1-416G>C single nucleotide polymorphism and asthma in Caucasians. Additionally, according to our analyses, TIM-1 5383_5397 insertion/deletion polymorphism was not correlated with asthma in both Asians and Caucasians.

CONCLUSIONS

In conclusion, our findings suggest that TIM-1-416G>C single nucleotide polymorphism is associated with asthma susceptibility for the Asian ethnicity in certain genetic models. However, TIM-1 5383_5397 insertion/deletion polymorphism may not be correlated with the risk of asthma.

Association analysis of -416 G>C polymorphism of T-cell immunoglobulin and mucin domain-1 gene with asthma in Iran

TIM (T-cell immunoglobulin (Ig) and mucin domain)-1, one of the members of TIM family, expresses on Th2 cells and promotes the production of Th2 signature cytokines. This can increase a series of responses in these cells which could be one of the causes of asthma or asthma-related phenotypes. The aim of this study was to investigate whether a TIM-1 promoter single nucleotide polymorphism (SNP), -416 G>C, is associated with asthma in Iranian population. In this case-control study, existence of the -416 G>C polymorphism was assessed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in 300 patients with asthma (97 atopic, 203 nonatopic) and 309 healthy volunteers. Additionally, the relationship between these polymorphism genotypes and total serum IgE levels in this Iranian population was evaluated. We discovered a significant association between the -416 G>C polymorphism and atopic asthma susceptibility in the population, but this SNP showed no connection with nonatopic asthma (P < 0.05). However, our results showed significant relation between this polymorphism and serum IgE level (P < 0.05). Our results suggest that -416 G>C polymorphism in TIM-1 gene could be a predisposing factor for atopic asthma in Iranian population, and CC genotype of this SNP can be associated with increased level of IgE in patients with asthma in the same population.

Protective association of TIM1-1454G>a polymorphism with asthma in a North Indian population

PURPOSE

TIM1 is a key regulator of Th2-dominated immune responses, including allergy, asthma, autoimmunity, and response to the pathogens. They are mainly expressed by hepatocytes and lymphoid cells. Analysis of the sequence of TIM1 was found to have range of SNPs which increases the transcriptional activity of the TIM1 gene.

METHODS

A case-control study was conducted with a total of 964 subjects, including 483 healthy controls and 481 asthma patients in the present study. DNA samples were extracted from blood, and genotyping was done using polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

Statistical analysis revealed that both heterozygous (GA) as well as the mutant (AA) genotype of -1454G>A (rs41297579) polymorphism shows resistance toward asthma with OR = 0.74, 95 % CI (0.55-0.98), p = 0.029 and OR = 0.43, 95 % CI (0.28-0.65), p = 0.000, respectively. The mutant (A) allele was also found to be highly protective toward asthma with OR = 0.68, 95 % CI (0.56-0.82) p = 0.000. However, no statistical difference was found between the TIM1-416G>C (rs9313422) polymorphism and asthma patients (p > 0.05).

CONCLUSIONS

This is the first study conducted in India conferring -1454G>A polymorphism provides resistance toward asthma while lack of association was found between -416G>C polymorphism and asthma in the studied North Indian population.

Pooled-analysis of the association between TIM-1 5383_5397 insertion/deletion polymorphism and asthma susceptibility

The T cell immunoglobulin (Ig) domain and mucin domain 1 (TIM-1) gene play an important role in pathogenesis of asthma. We investigate the association between the TIM-1 5383_5397 insertion/deletion polymorphism (rs45623443) and the risk of asthma in an asthma case-control study, and added these data to a literature-based meta-analysis. The TIM-1 5383_5397 insertion/deletion polymorphism genotype was analyzed in 156 asthma patients and 162 healthy subjects from Han Chinese population. We combined our data with that from previously published studies and performed a meta-analysis to evaluate the effect of the gene. Through regression model, we found no significant association for TIM-1 5383_5397 insertion/deletion polymorphism in our cohort. Meta-analysis, comprising a total of 1,577 asthma cases and 1,781 controls, revealed that no significant association between and asthma susceptibility was observed (OR = 0.99, 95 % CI = 0.83-1.20 for Ins vs. Del; OR = 1.01, 95 % CI = 0.74-1.37 for Ins/Ins vs. Ins/Del + Del/Del; OR = 0.96, 95 % CI = 0.78-1.18 for Ins/Ins + Ins/Del vs. Del/Del). The present meta-analysis suggested that TIM-1 5383_5397 insertion/deletion polymorphism may not substantially contribute to asthma susceptibility. However, gene-gene and gene-environment interaction effects and other considerations involving this polymorphism may exit.

Association of Hepatitis A exposure and TIM-1 with childhood allergic asthma

BACKGROUND

Hepatitis A virus (HAV) receptor (TIM-1) polymorphism plays an important role in asthma and autoimmune diseases. Objective. To analyze the association of TIM-1 polymorphism and HAV infection with childhood allergic asthma in Southwest China.

METHODS

TIM-1 exon 4 (157insMTTTVP) and two polymorphism loci, -416G>C and -1454G>A, in the HAV receptor promoter region were studied. Polymerase chain reaction (PCR) was used to test the genotypes of three polymorphism loci among 579 cases of asthma and 524 controls. The HAV infection status was determined in a case-control study with stratified analysis.

RESULTS

HAV exposure associated with childhood allergic asthma in the study population was compared with controls (odds ratio (OR) = 0.181, 95% confidence interval (CI) 0.126-0.260, p < .001). The -416G>C polymorphism was associated with asthma (OR = 1.384, 95% CI 1.148-1.669, p < .001), but the insertion variant 157delMTTTVP of exon 4 and the -1454G>A polymorphism were not.

CONCLUSION

Our results indicated that the -416G>C polymorphism of the TIM-1 gene is associated with childhood allergic asthma, providing a better understanding of the pathogenesis of the allergic asthma among children aged below 15 years in Southwest China.

Polymorphisms of the TIM-1 gene are associated with rheumatoid arthritis in the Chinese Hui minority ethnic population

The T-cell immunoglobulin and mucin domain 1 (TIM-1) is known to be associated with susceptibility to rheumatoid arthritis (RA). We investigated the association of four single-nucleotide polymorphisms (SNPs) in the promoter region of the TIM-1 gene with susceptibility to RA in a Chinese Hui ethnic minority group. Using RFLP or sequence specific primer-PCR, 118 RA patients and 118 non-arthritis control individuals were analyzed for the -1637A>G, -1454G>A, -416G>C, and -232A>G SNPs in the TIM-1 gene. The polymorphisms -232A>G and -1637A>G in the promoter region of TIM-1 were found to be associated with susceptibility to the RA gene in the Hui population, while -416G>C and -1454G>A SNPs were not. Of these, the polymorphism of -232A>G is inconsistent with that found in a Korean population, suggesting that genetic variations of the TIM-1 gene contribute to RA susceptibility in different ways among different populations. Based on haplotype analysis, individuals with haplotypes AGCA (Χ(2) = 22.0, P < 0.01, OR (95%CI) >1), AGCG (Χ(2) = 18.16, P < 0.01, OR (95%CI) >1) and AGGA (Χ(2) = 5.58, P < 0.05, OR (95%CI) >1) are at risk to develop RA in the Chinese Hui population; those with the GAGA (Χ(2) = 7.44, P < 0.01, OR (95%CI) <1) haplotype may have a decreased likelihood of RA. GGCA and GGCG are more common in both RA and non-RA subjects. We conclude that -1637A>G and -232A>G polymorphisms of TIM-1 are associated with susceptibility to RA in the Chinese Hui population.

Tim1 and Tim3 are not essential for experimental allergic asthma

Background

Initial studies suggested that polymorphisms in Tim1 and Tim3 contribute to the development of airway hyperreactivity (AHR) in an acute mouse model of asthma. This was also mirrored in human genetic studies where polymorphisms in Tim1 and Tim3 have been associated with atopic populations.

Objective

Further studies using anti-Tim1 or -Tim3 antibodies, or Tim fusion proteins, have also suggested that these molecules may function as regulators of type-1 and type-2 immunity. However, their role in the development of AHR and airway inflammation remains unclear. Given the proposed roles for Tim1 and Tim3 in type-1 and type-2 responses, we sought to determine whether these molecules were important in regulating antigen-driven lung allergy and inflammation.

Method

We used Tim1- and Tim3-deficient mice and determined how the development of allergic lung inflammation was affected.

Results

AHR was induced normally in the absence of both Tim1 and Tim3, although Tim1-deficient mice did show a small but significant decrease in cell infiltration in the lung and blood eosinophilia. Although Tim3 was expressed on CD4⁺ T cells in the allergic lung, Tim1 expression was restricted to CD86⁺ B cells.

Conclusions and clinical relevance

Thus, Tim1 and Tim3 are not essential for the induction of the type-2 response in lung allergy. This is contrary to what was proposed in a number of other studies using neutralizing and activating antibodies and questions the clinical relevance of Tim1 and Tim3 for novel allergy therapies.

Cite this as: J. L. Barlow, S. H. Wong, S. J. Ballantyne, H. E. Jolin and A. N. J. McKenzie, Clinical & Experimental Allergy, 2011 (41) 1012–1021.

Polymorphisms of the TIM-1 and TIM-3 genes are not associated with systemic lupus erythematosus in a Chinese population

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune diseases, which affects multiple organ systems such as kidney. The imbalance of T-helper 1 (Th1)/Th2 cells is critical in the pathogenesis of SLE. The T-cell immunoglobulin mucin (TIM) proteins comprise a family of cell surface molecules expressed on T cells that regulate Th1- and Th2-cell-mediated immunity. Recent work has found increased expression of TIM-1 and TIM-3 ligand (galactin-9) mRNA in SLE patients and implied that TIM proteins might be involved in the pathogenesis of SLE. In this study, genotyping of single-nucleotide polymorphisms (SNPs) was performed for TIM-1 (rs1501909 and rs12522248) and TIM-3 (rs9313439 and rs10515746) in 202 SLE patients and 217 healthy individuals in a Chinese population. Results showed no significant differences existed between the patients with SLE and the controls as well as SLE patients with nephritis and those without nephritis, in all four SNPs. The findings suggest that the polymorphisms of TIM gene family might not contribute to SLE susceptibility in the Chinese population. However, it should be noted that the statistical power of our study is relatively low, which likely did not have adequate power to detect the actual correlation between the selected SNPs and SLE susceptibility; moreover, we cannot discard a possible association of other variants within the region covering TIM with SLE as a genetic risk factor, with larger samples in different populations.

Specific immunotherapy suppresses Th2 responses via modulating TIM1/TIM4 interaction on dendritic cells

BACKGROUND

Specific immunotherapy (SIT) is the only curable remedy for allergic disorders currently; however, the underlying mechanism is not fully understood yet. This study aimed to elucidate the mechanism of SIT on suppressing TIM4 (T cell immunoglobulin mucin domain molecule 4) expression in dendritic cells (DCs) and modulating the skewed T helper 2 (Th2) responses in patients with airway allergy.

METHODS

Twenty patients with allergic rhinitis (AR) were treated with SIT for 3 months. Before and after SIT, the expression of TIM4 in peripheral DC and TIM1 in Th2 cells was examined. The role of Fc gamma receptor (FcgammaR) I and II in modulating the expression of TIM4 in DCs was investigated.

RESULTS

The interaction of TIM1/TIM4 played a critical role in sustaining the polarization status of Th2 cells in AR patients. Cross-linking FcgammaRI by antigen/IgG complexes increased the production of TIM4 by dendritic cells via upregulating tumor necrosis factor-alpha in DCs. Exposure to microbial products promoted the expression of FcgammaRI in DCs that further increased the expression of TIM4. Exposure to specific antigens alone upregulated the expression of FcgammaRII in DCs, that suppressed the expression of TIM4.

CONCLUSIONS

We conclude that SIT suppresses the skewed Th2 responses via disrupting the interaction of TIM1/TIM4 in antigen-specific Th2 cells.

TIM genes: a family of cell surface phosphatidylserine receptors that regulate innate and adaptive immunity

The TIM (T cell/transmembrane, immunoglobulin, and mucin) gene family plays a critical role in regulating immune responses, including allergy, asthma, transplant tolerance, autoimmunity, and the response to viral infections. The unique structure of TIM immunoglobulin variable region domains allows highly specific recognition of phosphatidylserine (PtdSer), exposed on the surface of apoptotic cells. TIM-1, TIM-3, and TIM-4 all recognize PtdSer but differ in expression, suggesting that they have distinct functions in regulating immune responses. TIM-1, an important susceptibility gene for asthma and allergy, is preferentially expressed on T-helper 2 (Th2) cells and functions as a potent costimulatory molecule for T-cell activation. TIM-3 is preferentially expressed on Th1 and Tc1 cells, and generates an inhibitory signal resulting in apoptosis of Th1 and Tc1 cells. TIM-3 is also expressed on some dendritic cells and can mediate phagocytosis of apoptotic cells and cross-presentation of antigen. In contrast, TIM-4 is exclusively expressed on antigen-presenting cells, where it mediates phagocytosis of apoptotic cells and plays an important role in maintaining tolerance. TIM molecules thus provide a functional repertoire for recognition of apoptotic cells, which determines whether apoptotic cell recognition leads to immune activation or tolerance, depending on the TIM molecule engaged and the cell type on which it is expressed.

TIM genes: a family of cell surface phosphatidylserine receptors that regulate innate and adaptive immunity

The TIM (T cell/transmembrane, immunoglobulin, and mucin) gene family plays a critical role in regulating immune responses, including allergy, asthma, transplant tolerance, autoimmunity, and the response to viral infections. The unique structure of TIM immunoglobulin variable region domains allows highly specific recognition of phosphatidylserine (PtdSer), exposed on the surface of apoptotic cells. TIM-1, TIM-3, and TIM-4 all recognize PtdSer but differ in expression, suggesting that they have distinct functions in regulating immune responses. TIM-1, an important susceptibility gene for asthma and allergy, is preferentially expressed on T-helper 2 (Th2) cells and functions as a potent costimulatory molecule for T-cell activation. TIM-3 is preferentially expressed on Th1 and Tc1 cells, and generates an inhibitory signal resulting in apoptosis of Th1 and Tc1 cells. TIM-3 is also expressed on some dendritic cells and can mediate phagocytosis of apoptotic cells and cross-presentation of antigen. In contrast, TIM-4 is exclusively expressed on antigen-presenting cells, where it mediates phagocytosis of apoptotic cells and plays an important role in maintaining tolerance. TIM molecules thus provide a functional repertoire for recognition of apoptotic cells, which determines whether apoptotic cell recognition leads to immune activation or tolerance, depending on the TIM molecule engaged and the cell type on which it is expressed.

Association study between vitamin D receptor gene polymorphisms and asthma in the Chinese Han population: a case-control study

BACKGROUND

Modulation of the immune system is one of the principal roles of Vitamin D, for which the effects are exerted via the vitamin D receptor (VDR). Importantly, variants in the VDR gene have been susceptible in the past to raise the risk of asthma in several populations. These effects of VDR allelic markers remain speculative in the Chinese Han population.

RESULTS

A case-control study of 1090 individuals including 567 asthmatic patients was realized on five SNPs within the VDR gene. Only rs7975232 (ApaI) marker showed a significant association with asthma (P = 0.009). Haplotype analysis of the five VDR polymorphisms showed a significant association with asthma (global-p value = 0.012).

CONCLUSION

Although the susceptibility of VDR gene variants with asthma could not be confirmed for all SNPs tested in this study, the significant association obtained for rs7975232 provides evidence for a previously unknown report about the Chinese Han population and may raise the susceptibility of VDR to be a candidate gene for asthma.

Association of TIM4 promoter polymorphism -1419G>A with childhood asthma in a Chinese Han population

TIM4, which is expressed on dendritic cells and macrophages, plays an important role in the proliferation of T helper type 2 (Th2) cells. Asthma, as a complex genetic disease, is thought to arise from the development of a Th2-lymphocyte-predominant immune response. To evaluate the effects of the promoter polymorphisms (-1419G>A and -1609G>A) in TIM4 on asthma susceptibility, case-control and family-based association studies were conducted by polymerase chain reaction and restriction fragment length polymorphism. Our results showed that TIM4 -1419G>A polymorphism was associated with asthma susceptibility in our study population (chi(2)= 9.88, P < 0.001, OR = 1.91, 95% CI 1.37-2.64). The -1419A/A and -1419A/G genotypes were observed more common in asthmatic group (6.3%, 41.8%) than in control group (1.7%, 29.3%). No significant difference was found in genotype and allele frequencies of TIM4 -1619G>A polymorphism between asthmatic and control groups. No association between the two SNPs and total serum IgE levels, lung function was observed. In conclusion, the present findings suggest that TIM4 -1419G>A polymorphism might be the genetic factor for the risk of childhood asthma in Chinese Han population.

The Asian side of asthma and allergy

PURPOSE OF REVIEW

There is wide variation in the global epidemiology of allergic diseases, and the prevalence rates of asthma and allergy differ significantly among different Asian populations. The diversity of environment and ethnic background in Asia provide excellent opportunities for research into the environmental and genetic determinants of asthma and allergies. This review summarizes important lessons learnt from research findings from Asia on asthma and allergy.

RECENT FINDINGS

Recent epidemiologic studies revealed wide variation and increasing prevalence of asthma and allergy in many Asian countries. Comparative studies of population of the same ethnic background living in different environments revealed important environmental risk factors for asthma. Ambient air pollution plays an important role in the morbidity of patients with asthma but does not seem to affect the prevalence of asthma. There were many genetic association studies for allergic diseases from Asia. These studies identified novel gene targets, such as CD40, DCNP1 and PTGS2, for asthma and allergen sensitization whereas many others replicated the genetic associations on known candidate genes for asthma and atopic dermatitis.

SUMMARY

Epidemiologic and genetic researches in Asia advance our knowledge on the disease prevalence, healthcare burden and pathogenesis of asthma and allergy.

Distribution characteristics and linkage disequilibrium of TIM4 promoter polymorphisms in asthma patients of Chinese Han population

To investigate the distribution characteristics and linkage disequilibrium of T cell immunoglobulin domain and mucin domain protein 4 (TIM4) promoter polymorphisms in asthma patients of Chinese Han population, the promoter region of TIM4 was re-sequenced by PCR-sequencing, and linkage disequilibrium was analyzed by SHEsis software. Four single nucleotide polymorphisms (SNPs) in the promoter region of TIM4 were detected, including two new SNPs (at positions-1609,-153) and two reported SNPs (rs6874202, rs6882076). The frequency distribution of rs6882076 was different among different races (P<0.05). In addition, linkage disequilibrium among the SNPs of the promoter region of TIM4 was found and GGTG was the predominant haplotype. There were four SNPs in the promoter region of TIM4 in asthma patients of Chinese Han population, which were in linkage disequilibrium.