IRG1 increases MHC class I level in macrophages through STAT-TAP1 axis depending on NADPH oxidase mediated reactive oxygen species.

The major histocompatibility complex (MHC) is the connection between innate immunity and acquired immune system. Recently, many studies reported that the immunoresponsive gene 1 (IRG1) play an important role on innate immunity including reactive oxygen species (ROS), antiviral effect and expression of inflammatory factors. However, the function of IRG1 in antigen presenting remains unclear. In this study, we found that overexpressed-IRG1 promoted MHC I level instead of MHC II in macrophages membrane. Besides, IRG1 increased expression of some transporter proteins associated with antigen processing involving TAP1, PSMB9 depending on ROS. By detecting the activation of glucose-6-phosphate dehydrogenase (G6PD), we confirmed that IRG1 could increase ROS level by promoting pentose phosphate pathway (PPP). DPI, an inhibitor of NADPH oxidase (NOX), also significant attenuated TAP1 and MHC I level in IRG1-overexpressed macrophages. Finally, results showed that phosphorylation of STAT1/3 involved in IRG1-mediated TAP1 and MHC I expression. In conclusion, IRG1 increased MHC class I level in macrophages through STAT1/3-TAP1 axis depending on PPP and NOX mediated ROS.

Polymorphisms in IRG1 gene associated with immune responses to hepatitis B vaccination in a Chinese Han population and function to restrain the HBV life cycle.

Vaccination against the hepatitis B virus (HBV) is extensively used as an effective method to prevent HBV infection. However, nearly 10% of healthy adults fail to produce a protective level of antibodies against the hepatitis B vaccine, and multiple genetic variants are known to affect the immune response to the hepatitis B vaccine. The aim of the present study was to investigate the association between polymorphisms in immunoresponsive gene 1 (IRG1) gene and the immune response to hepatitis B vaccination in a Chinese Han population. Four single nucleotide polymorphisms (SNPs) located in the IRG1 gene were genotyped in 1230 high-responders and 451 non-responders to hepatitis B vaccination. The SNPs rs17470171 and rs17385627 were associated with the immune response to hepatitis B vaccination (P = 0.014 and 0.029, respectively). In addition, the haplotypes G-A-A-A (rs614171-rs17470171-rs9530614-rs17385627, P = 0.0042, OR = 0.68) and A-A (rs17470171-rs17385627, P = 0.0065, OR = 0.72) exerted a protective role in the immune response to hepatitis B vaccination. Allele 'A' of rs17470171 and allele 'A' of rs17385627 show higher levels of expression for the IRG1 gene compared with allele 'C' of rs17470171 and allele 'T' of rs17385627 as demonstrated by luciferase reporter and overexpression assays. In addition, we observed that IRG1 inhibited the HBV life cycle and that IRG1 rs17385627 allele 'A' was more effective than rs17385627 allele 'T' at eliminating HBV in HepG2.2.15 cells. These findings suggest that polymorphisms in the IRG1 gene are associated with the immune response to hepatitis B vaccination. The antiviral effect of IRG1 was confirmed using HBV infection cell models.

Positive Association Between Type 2 Diabetes Risk Alleles Near CDKAL1 and Reduced Birthweight in Chinese Han Individuals.

BACKGROUND: Fetal insulin hypothesis was proposed that the association between low birth weight and type 2 diabetes is principally genetically mediated. The aim of this study was to investigate whether common variants in genes CDKAL1, HHEX, ADCY5, SRR, PTPRD that predisposed to type 2 diabetes were also associated with reduced birthweight in Chinese Han population. METHODS: Twelve single nucleotide polymorphisms (rs7756992/rs10946398 in CDKAL1, rs1111875 in HHEX, rs391300 in SRR, rs17584499 in PTPRD, rs1170806/rs9883204/rs4678017/rs9881942/rs7641344/rs6777397/rs6226243 in ADCY5) were genotyped in 1174 unrelated individuals born in Peking Union Medical College Hospital from 1921 to 1954 by TaqMan allelic discrimination assays, of which 645 had normal glucose tolerance, 181 had developed type 2 diabetes and 348 impaired glucose regulation. Associations of these 12 genetic variants with birthweight and glucose metabolism in later life were analyzed. RESULTS: Birthweight was inversely associated with CDKAL1-rs10946398 (ß = -41 g [95% confidence interval [CI]: -80, -3], P = 0.034), common variants both associated with increased risk of impaired glucose metabolism and decreased insulin secretion index later in life. After adjusting for sex, gestational weeks, parity and maternal age, the risk allele of CDKAL1-rs7756992 was associated with reduced birthweight (ß = -36 g [95% CI: -72, -0.2], P = 0.048). The risk allele in SRR showed a trend toward a reduction of birthweight (P = 0.085). CONCLUSIONS: This study identified the association between type 2 diabetes risk variants in CDKAL1 and birthweight in Chinese Han individuals, and the carrier of risk allele within SRR had the trend of reduced birthweight. This demonstrates that there is a clear overlap between the genetics of type 2 diabetes and fetal growth, which proposes that lower birth weight and type 2 diabetes may be two phenotypes of one genotype.

Genetic variants in five novel loci including CFB and CD40 predispose to chronic hepatitis B.

UNLABELLED: Hepatitis B virus affects more than 2 billion people worldwide, 350 million of which have developed chronic hepatitis B (CHB). The genetic factors that confer CHB risk are still largely unknown. We sought to identify genetic variants for CHB susceptibility in the Chinese population. We undertook a genome-wide association study (GWAS) in 2,514 CHB cases and 1,130 normal controls from eastern China. We replicated 33 of the most promising signals and eight previously reported CHB risk loci through a two-stage validation totaling 6,600 CHB cases and 8,127 controls in four independent populations, of which two populations were recruited from eastern China, one from northern China and one from southern China. The joint analyses of 9,114 CHB cases and 9,257 controls revealed significant association of CHB risk with five novel loci. Four loci are located in the human leukocyte antigen (HLA) region at 6p21.3, including two nonsynonymous variants (rs12614 [R32W] in complement factor B [CFB], Pmeta =1.28 × 10(-34) ; and rs422951 [T320A] in NOTCH4, Pmeta = 5.33 × 10(-16) ); one synonymous variant (rs378352 in HLA-DOA corresponding to HLA-DOA*010101, Pmeta = 1.04 × 10(-23) ); and one noncoding variant (rs2853953 near HLA-C, Pmeta = 5.06 × 10(-20) ). Another locus is located at 20q13.1 (rs1883832 in the Kozak sequence of CD40, Pmeta = 2.95 × 10(-15) ). Additionally, we validated seven of eight previously reported CHB susceptibility loci (rs3130542 at HLA-C, rs1419881 at TCF19, rs652888 at EHMT2, rs2856718 at HLA-DQB1, rs7453920 at HLA-DQB2, rs3077 at HLA-DPA1, and rs9277535 at HLA-DPA2, which are all located in the HLA region, 9.84 × 10(-71) ≤ Pmeta ≤ 9.92 × 10(-7) ). CONCLUSION: Our GWAS identified five novel susceptibility loci for CHB. These findings improve the understanding of CHB etiology and may provide new targets for prevention and treatment of this disease.

CD3Z genetic polymorphism in immune response to hepatitis B vaccination in two independent Chinese populations.

Vaccination against hepatitis B virus is an effective and routine practice that can prevent infection. However, vaccine-induced immunity to hepatitis B varies among individuals. CD4(+) T helper cells, which play an important role in both cellular and humoral immunity, are involved in the immune response elicited by vaccination. Polymorphisms in the genes involved in stimulating the activation and proliferation of CD4(+) T helper cells may influence the immune response to hepatitis B vaccination. In the first stage of the present study, a total of 111 single nucleotide polymorphisms (SNPs) in 17 genes were analyzed, using the iPLEX MassARRAY system, among 214 high responders and 107 low responders to hepatitis B vaccination. Three SNPs (rs12133337 and rs10918706 in CD3Z, rs10912564 in OX40L) were associated significantly with the immune response to hepatitis B vaccination (P = 0.008, 0.041, and 0.019, respectively). The three SNPs were analyzed further with the TaqMan-MGB or TaqMan-BHQ probe-based real-time polymerase chain reaction in another independent population, which included 1090 high responders and 636 low responders. The minor allele 'C' of rs12133337 continued to show an association with a lower response to hepatitis B vaccination (P = 0.033, odds radio = 1.28, 95% confidence interval = 1.01-1.61). Furthermore, in the stratified analysis for both the first and second populations, the association of the minor allele 'C' of rs12133337 with a lower response to hepatitis B vaccination was more prominent after individuals who were overweight or obese (body mass index ≥25 kg/m(2)) were excluded (1(st) stage: P = 0.003, 2(nd) stage: P = 0.002, P-combined = 9.47e-5). These findings suggest that the rs12133337 polymorphism in the CD3Z gene might affect the immune response to hepatitis B vaccination, and that a lower BMI might increase the contribution of the polymorphism to immunity to hepatitis B vaccination.

Evaluation of genetic susceptibility loci for chronic hepatitis B in Chinese: two independent case-control studies.

BACKGROUND: A recent genome-wide scan has identified two genetic variants in the HLA-DP region strongly associated with hepatitis B infection in Japanese. This study evaluates the effects of these risk variants in Chinese, where the HBV infection is the most popular in the world. METHODS AND FINDINGS: We have assessed the relationship between these two single nucleotide polymorphisms (rs3077 and rs9277535) and chronic hepatitis B infection in two independent case-control studies. The first population in Chinese Han included 736 patients and 782 spontaneously recovered controls. The second set was established in Chinese Zhuang minority of 177 patients and 208 controls. Both A alleles of rs3077 and rs9277535 significantly deceased the risk to CHB in Chinese Han (OR = 0.540, 95%CI: 0.464-0.628, P = 4.068×10(-16) and OR = 0.696, 95%CI: 0.601-0.806, P = 1.062×10(-6), respectively). Conceivably, rs9277535 was found to be associated with decreased risk of the disease in Chinese Zhuang, with an OR of 0.606 (95%CI, 0.441-0.833, P = 0.002). CONCLUSION: Chronic hepatitis B susceptibility loci in HLA-DP region (rs3077 and rs9277535) identified by genome-wide scan in Japanese population were validated in Chinese population. These findings might provide clues to develop screening and surveillance strategies.