Yunjie Dan

Regulatory polymorphisms in the IL-10 gene promoter and HBV-related acute liver failure in the Chinese population

Summary.  Recent reports indicated that high levels of interleukin 10 (IL‐10) contribute to the monocytes paralysis and poor clinical outcome in acute liver failure (ALF). Polymorphisms in the promoter region of IL‐10 affect IL‐10 production and confer susceptibility to inflammatory diseases. The aim of this study was to determine the possible association of the three polymorphisms (A‐1082G, T‐819C, A‐592C) in the IL‐10 gene promoter with the susceptibility to hepatitis B virus (HBV)‐related ALF in a Chinese population. The IL‐10 gene promoter polymorphisms were genotyped in 414 unrelated healthy blood donors, 367 asymptomatic HBV carriers and 345 HBV‐related ALF patients. Functional analyses were conducted to verify the biological significances of the associated genetic variations. The allele frequencies of IL‐10−592C and −819C were significantly higher in HBV‐related ALF patients than in blood donors and asymptomatic HBV carriers. Logistic regression analysis and stratification analysis with adjustment for age and sex indicated that the polymorphisms of A‐592C and T‐819C were associated with susceptibility to HBV‐related ALF (P = 6.9 × 10−7), and the ‐1082A‐819C‐592C haplotype in the IL‐10 gene promoter were associated with an increased susceptibility to ALF in HBV carriers (dominant model, P = 0.0002, odds ratio = 1.60, 95% CI 1.25–2.07). Functional analyses showed that the A‐592C polymorphism is a nuclear proteins binding site, and the disease susceptible −592C allele had a higher transcription activity compared with −592A allele. This study emphasizes the importance of IL‐10 in the pathophysiology of HBV‐related ALF on the population level.

A Common Promoter Variant of TBX21 is Associated with Allele Specific Binding to Yin‐Yang 1 and Reduced Gene Expression

T‐bet is a key regulator for the lineage commitment in CD4 T helper (Th) 1 cells by activating the hallmark production of interferon‐γ, and its expression level is linked to autoimmune, infectious, and allergic diseases. A T to C base substitution has been identified at position ‐1993 in the TBX21 (encoding T‐bet) promoter and has been associated with asthma and systemic lupus erythematosus. This study aimed to investigate the molecular mechanisms responsible for the influence of the T‐1993C polymorphism on transcription and its functional effect by luciferase reporter, EMSAs, Chromatin immunoprecipitation assay, and flow cytometric analysis of intracellular T‐bet, IFN‐γ and IL‐4 expression in activated CD4+ T cells. The presence of a ‐1993T allele obviously increases promoter activity compared with that of a promoter with a ‐1993C allele. TBX21 promoter carrying ‐1993C allele possesses significantly stronger binding affinity to the Yin Yang 1 (YY1) transcription factor than that carrying ‐1993T allele. YY1 overexpression decreased TBX21 promoter function in a T cell line, demonstrating that this element functions as a repressor. The C to T base exchange relieves the repression mediated by YY1. The individuals carrying ‐1993C allele were determined to have significantly diminished expression of TBX21 and IFN‐γ and increased IL‐4 production in cells compared with the individuals carrying ‐1993T allele (P < 0.05). These findings demonstrate that the TBX21 T‐1993C polymorphism represses TBX21 expression and Th1 cytokine production through control of YY1, which might result in the imbalance between Th1 and Th2 immune responses in autoimmune or allergic diseases.

Association of TBX21 gene haplotypes in a Chinese population with systemic lupus erythematosus

Objective: T-cell-specific T-box transcription factor (T-bet) is a member of the T-box family of transcription factors regulating type 1 T-helper (Th1) cell development and is thought to be linked with several autoimmune diseases including systemic lupus erythematosus (SLE). The aim of this study was to evaluate whether T-bet gene (TBX21) polymorphisms or its haplotypes are associated with SLE in a Chinese population. Methods: The study included 248 cases with SLE and 261 gender- and age-matched healthy controls. The polymorphisms T-1993C (rs4794067) and T-1514C (rs17250932) in the TBX21 promoter were identified by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Results: The frequency of both the -1993T and the -1514T allele were significantly higher in SLE patients than in controls. By haplotype analysis, there was significantly decreased frequency of the haplotype at positions -1993C/-1514C in the case group compared with the control group (p = 0.0002). Multifactorial logistic regression analysis showed that individuals with CC/CC haplotype homozygotes had a decreased susceptibility to SLE [p = 0.0004, odds ratio (OR) 0.316, 95% confidence interval (CI) 0.167–0.599]. Conclusion: Our results suggest that the -1993C/-1514C haplotype may be a protective factor for genetic susceptibility to SLE in the Chinese population.

SLCO1B1 *15 haplotype is associated with rifampin-induced liver injury

The organic anion transporting polypeptide 1B1 (OATP1B1, encoded by SLCO1B1) plays an important role in the transport of endogenous and xenobiotic compounds, such as bile acids and rifampin. In this study, the association between OATP1B1 polymorphisms and rifampin hepatotoxicity was investigated using integrated population genetic analysis and functional studies. A total of 273 unrelated patients treated with rifampin were recruited. The allele frequencies were examined in patients with drug (rifampin)-induced liver injury (DILI) (n = 118) and without (non-DILI) (n = 155). Functional analyses were conducted to determine whether the inhibition of bile acids by rifampin was associated with OATP1B1 variants. In the present study, 24 single nucleotide polymorphisms (SNPs) in OATP1B1 were detected in a Chinese population, with two of them causing an amino acid change (rs2306283 and rs4149056). The haplotypes constructed by these two SNPs were OATP1B1 *1a, *1b, *5 and *15, with their respective frequencies being 23.44, 66.30, 0.73 and 9.52% in a total of 273 individuals. The logistic regression analysis indicated that the *15 haplotype was associated with susceptibility to DILI (p = 0.03, OR = 2.04, 95% CI 1.05-3.96). The frequency of the *15 haplotype in DILI patients was significantly higher than that in non-DILI patients (p = 0.03). In the subgroup analysis, the *15 haplotype was associated with susceptibility to cholestatic/mixed injury (p = 0.03, OR = 2.31, 95% CI 1.06-5.02). Functional assessment of the OATP1B1 *15 haplotype revealed that the activity of bile acid uptake was markedly reduced compared to the three other haplotypes. In the inhibition study, the inhibition by rifampin in the *15 haplotype was greater compared to that in the other haplotypes. These results suggest that the OATP1B1 *15 haplotype is an important predisposing factor for rifampin-induced liver injury.

Relationship between HLA-DP gene polymorphisms and clearance of chronic hepatitis B virus infections: Case–control study and meta-analysis

Hepatitis B virus (HBV) infection is a serious public health problem worldwide. Two common genetic variants (rs3077 and rs9277535) of human leukocyte antigen DP (HLA-DP) have been reported to be associated with persistent HBV infection in populations of Japan and Thailand. To confirm whether the association can be replicated in Chinese populations, an independent case-control study were conducted, and two polymorphisms (rs3077 and rs9277535) were genotyped using the TaqMan SNP genotyping assay in 282 persistent chronic HBV carriers and 64 spontaneously HBV recovered carriers. To provide a more definitive conclusion, a meta-analysis combining and summarizing five studies was performed by random-effects model using the DerSimonian and Lairds method. By using logistic regression analysis with adjustment for covariates, including age, sex, and alcohol consumption, the results of our independent case-control study showed that the minor alleles homozygote (AA genotype) of rs3077 and rs9277535 was significantly associated with decreasing risk/protection of HBV persistent chronic infection (for rs3077: P=0.0017, OR=0.29, 95% CI=0.13-0.62; for rs9277535, P=0.0004, OR=0.26, 95% CI=0.12-0.54). The results of meta-analysis pooling all eligible studies also showed that rs3077-A and rs9277535-A alleles were associated with an increased clearance rate to HBV infection (rs3077: OR=0.57, 95% CI=0.44-0.75; rs9277535: OR=0.56, 95% CI=0.47-0.63). These results further confirmed the strong influence of HLA-DP gene variants on risk of spontaneous HBV clearance from persistent HBV infection. Both A alleles of HLA-DP SNP rs3077 and rs9277535 showed strong protective effects for spontaneous HBV clearance from persistent HBV infection in the Han Chinese population.

A cis-acting regulatory variation of the estrogen receptor α (ESR1) gene is associated with hepatitis B virus-related liver cirrhosis.

The hepatic fibrogenesis and sexual dimorphism of hepatitis B virus‐related liver cirrhosis (HBV‐LC) are related to estrogen and its receptors. Abnormal expression of estrogen receptor α (ESR1) is implicated in the development of cirrhosis in both animal models and humans. Here, we examine whether the ESR1 polymorphisms are related to HBV‐LC risk among chronic HBV carriers, and we investigate the functional significance of positively associated polymorphisms. A total of 2,404 unrelated Chinese HBV carriers were recruited to conduct the two‐stage designed case–control study. Two ESR1 haplotype tagging polymorphisms, c.30T>C (rs2077647) and c.453‐397T>C (rs2234693), were genotyped in 1,285 patients with HBV‐LC and in 1,119 asymptomatic HBV carriers. We observed a significantly increased susceptibility to HBV‐LC associated with the c.30C allele (P = 4.2×10−8), c.453‐397C allele (P = 2.0×10−8), and [c.30C; c.453‐397C] haplotype (Dominant model, P = 8.85×10−10, odds ratio = 1.50, 95% CI 1.32∼1.71) compared with the T alleles and (c.30T; c.453‐397T) haplotype of c.30T>C and c.453‐397T>C polymorphisms, respectively. Functional analyses were conducted to verify the biological functions of the associated genetic variations and showed that the c.453‐397T>C polymorphism is a novel c.453‐397C allele‐specific and c‐myb‐dependent enhancer‐like cis‐acting regulatory variation and could be part of the genetic variations underlying the susceptibility of individuals to HBV‐LC. Hum Mutat 32:1128–1136, 2011. ©2011 Wiley‐Liss, Inc.

Effect of HLA-DP and IL28B gene polymorphisms on response to interferon treatment in hepatitis B e-antigen seropositive chronic hepatitis B patients

The reason why the majority of chronic hepatitis B (CHB) patients do not respond to conventional interferon (IFN)‐α or pegylated interferon (PEG IFN) treatment has not been formally demonstrated. The aim of this study was to investigate the association between single nucleotide polymorphisms (SNPs) and response to IFN‐α or PEG IFN therapy in Chinese patients with CHB.

Estrogen receptor alpha gene polymorphisms and risk of HBV-related acute liver failure in the Chinese population

BackgroundThe sexual dimorphism of hepatitis B virus (HBV) -related liver diseases is related with estrogen and its receptors. Recent reports indicate that abnormal expression of estrogen receptor alpha (ESR1) may be a hallmark for the progression of liver disease and HBV carriers presenting variant ESR1 have an extremely aggressive clinical course. Here we examine whether the ESR1 polymorphisms or its haplotypes are related to HBV-related acute liver failure (ALF) risk among chronic HBV carriers in a Chinese population.MethodsA total of 1216 unrelated Han Chinese HBV carriers were recruited in this hospital-based case–control study, including 359 HBV surface antigen (HBsAg) carriers affected with ALF and 857 asymptomatic HBsAg carriers. Two ESR1 haplotype tagging polymorphisms, c.30 T > C (rs2077647) and c.453-397 T > C (rs2234693), were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay.ResultsWe observed a significantly increased susceptibility to HBV-ALF associated with the c.30 C allele (P = 8.65 × 10-4), c.453-397 C allele (5.37 × 10-4) and [c.30 C; c.453-397 C] haplotype (Dominant model, P =0.0004, odds ratio = 1.53, 95% CI 1.23 ~ 1.96) compared with the T alleles and [c.30 T; c.453-397 T] haplotype of c.30 T > C and c.453-397 T > C polymorphisms, respectively.ConclusionsOur study suggests that [c.30 C; c.453-397 C] hapotype may be a risk factor for genetic susceptibility to HBV-related ALF in the Chinese population. It also emphasizes the importance of ESR1 in the pathophysiology of HBV-related ALF on the population level.

Association of TBX21 promoter polymorphisms with type 1 autoimmune hepatitis in a Chinese population

The T-box transcription factor T-bet is a key regulator for the lineage commitment in CD4 Th1 cells and CD8 T cells by activating the hallmark production of interferon-γ, and its expression level is linked to autoimmune diseases. T-1993C and T-1514C polymorphisms in the TBX21 gene (encoding T-bet) promoter can affect transcription activity. We investigated the distributions of these functional polymorphisms in 84 adult patients with type 1 autoimmune hepatitis (AIH-1) and 318 healthy controls. Intracellular T-bet staining of polarized CD4 Th1 cells from healthy controls corresponding to T-1993C genotypes were analyzed by flow cytometry. The -1993C allele frequency was 3.0% in AIH-1 and 11.8% in controls (p = 0.000 25). Individuals carrying the -1993C allele had a decreased risk to AIH-1 compared with those without the -1993C allele (p = 0.0016, odds ratio [OR] = 0.22, 95% confidence interval = 0.09-0.56). No association was found between the T-1514C polymorphism and AIH-1. The onset age of AIH-1 was also accelerated among -1993TT homozygotic individuals (p = 0.013). The fractions of T-bet positive Th1 cells in the -1993TT homozygotes were 2.2-fold higher than those in -1993CC homozygotes (p = 0.002). Our results suggest that the T-1993C polymorphism in the TBX21 promoter influences susceptibility to AIH-1 in a Chinese population.

Association of TBX21 T-1993C polymorphism with viral persistence but not disease progression in hepatitis B virus carriers

Aim:  Transcription factor T‐bet is responsible for the differentiation of naive T lymphocytes, and its expression level is linked with different responses to some viral infections, including hepatitis B virus (HBV) infection. In this report we examine whether promoter polymorphisms of the TBX21 gene (encoding T‐bet) are associated with susceptibility to HBV persistence or disease progression in chronic HBV carriers.