Yueran Zhao

Genome-wide association study identifies susceptibility loci for polycystic ovary syndrome on chromosome 2p16.3, 2p21 and 9q33.3

Polycystic ovary syndrome (PCOS) is a common metabolic disorder in women. To identify causative genes, we conducted a genome-wide association study (GWAS) of PCOS in Han Chinese. The discovery set included 744 PCOS cases and 895 controls; subsequent replications involved two independent cohorts (2,840 PCOS cases and 5,012 controls from northern Han Chinese; 498 cases and 780 controls from southern and central Han Chinese). We identified strong evidence of associations between PCOS and three loci: 2p16.3 (rs13405728; combined P-value by meta-analysis Pmeta = 7.55 × 10−21, odds ratio (OR) 0.71); 2p21 (rs13429458, Pmeta = 1.73 × 10−23, OR 0.67); and 9q33.3 (rs2479106, Pmeta = 8.12 × 10−19, OR 1.34). These findings provide new insight into the pathogenesis of PCOS. Follow-up studies of the candidate genes in these regions are recommended.

Polymorphisms of KIRs Gene and HLA-C Alleles in Patients with Ankylosing Spondylitis: Possible Association with Susceptibility to the Disease

IntroductionAn emerging body of evidence is accumulating to suggest that killer cell immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I ligands contribute to the pathogenesis of diverse kinds of autoimmune diseases. However, the functional effects of their polymorphism remain largely unknown to date. Thus, the present study was undertaken to determine the association of the polymorphisms KIRs gene and HLA-C alleles with the susceptibility to ankylosing spondylitis (AS) by means of polymerase chain reaction/sequence-specific primers for genotyping KIRs from genomic DNA of 119 patients with AS together with 128 healthy donors as a control group.Results and DiscussionWe found that the frequencies of KIR3DS1 and KIR2DL5 were statistically significantly higher in the patient group than those in the control group (P = 0.016 and P = 0.003, respectively). Meanwhile, the percentage of patients, who were carrying two or more of the activating KIRs, was higher than that of control group. With respect to HLA-C alleles, individuals with AS showed an increased frequency of HLA-Cw02. If HLA-C was divided into group 1 or group 2 based on whether there was an asparagine or lysine present at position 80 of the alpha-chain, HLA-C group 2 was more common in subjects with AS compared to control subjects. The genotype 2DS1+/HLA-C lys80+ was more common in subjects with AS. Moreover, the CD69 expression, a NK activation marker, remarkably increased in patient with AS.ConclusionIn conclusions, this study suggests that KIR3DS1 may severe as AS susceptive genes to trigger continuous injury of arthrosis. The imbalance of activating and inhibitory KIR as well as HLA-C group 1 and group 2 may be the key factor, which influences the pathogenesis of AS. Moreover, KIR2DS1 might associate with the susceptibility of AS by influencing NK cell activity once group 2 HLA-C ligands are present.

Association of +45G15G(T/G) and +276(G/T) polymorphisms in the ADIPOQ gene with polycystic ovary syndrome among Han Chinese women.

OBJECTIVE Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance (IR) and consequently with increased risk of metabolic disorders. Adiponectin is the most abundant adipocytokine and may play a role in the regulation of insulin sensitivity and IR in PCOS. The aim of the present study was to evaluate the genetic influence of the adiponectin (ADIPOQ) gene polymorphisms in the development of PCOS among Han Chinese women. METHODS Two single nucleotide polymorphisms (SNPs),+45G15G(T/G) and +276(G/T), in the ADIPOQ gene were genotyped in 120 patients with PCOS and 120 healthy control subjects. All of them were Han Chinese women. RESULTS Both SNPs were found to be significantly associated with PCOS (P=0.021, odds ratios=1.629, 95% confidence intervals: 1.074-2.469 and P=0.015, 1.576, 1.091-2.279 respectively). In SNP +276(G/T), the allele G was found to be significantly associated with increased fasting insulin levels, homeostasis model assessment to assess IR index, and area under the curve glucose levels, but decreased glucose and insulin ratio in the PCOS patients. Furthermore, the patients carrying genotypes G/G and G/T had significantly decreased levels of serum adiponectin (6.16+/-3.18 plus 5.93+/-3.23 vs 8.96+/-3.21 microg/ml, P=0.030) compared with the patients with genotype T/T. CONCLUSIONS The present study provides evidence that SNPs +45G15G(T/G) and +276(G/T) in the ADIPOQ gene are associated with PCOS in Han Chinese women. SNP +276(G/T) may contribute to an impact of insulin levels and IR, which are implicated in the susceptibility for PCOS.

Mutation analysis of NOBOX homeodomain in Chinese women with premature ovarian failure.

The newborn ovary homeobox gene (NOBOX) is an oocyte-specific homeobox gene that plays a critical role in early folliculogenesis, thus representing an attractive candidate gene for nonsyndromic ovarian failure. We investigated whether perturbation in the homeodomain region of NOBOX was present in Chinese women with premature ovarian failure (POF). We sequenced 200 Chinese patients with POF, and discovered only two known single nucleotide polymorphisms: in intron 6 (c.1154+11 T>C and c.1155-22 G>A); neither offers plausible explanations for POF. Failing to find causative mutation contrasts with our previous study in a caucasian sample, in which we found plausible homeobox mutation in 1 of 96 POF cases. Mutations in the homeobox domain of NOBOX are not common explanations for POF in Chinese women.

Polymorphisms of KIR Gene and HLA-C Alleles: Possible Association with Susceptibility to HLA-B27-Positive Patients with Ankylosing Spondylitis

AbstractAccumulating evidences indicate that killer cell immunoglobulin-like receptors (KIRs) and their corresponding specific HLA-C ligands contribute to the pathogenesis of multiple autoimmune diseases via the modulation of natural killer (NK) cell and T cell functions. The present study was performed to investigate whether the polymorphism of KIR genes and HLA ligands associates with the susceptibility of ankylosing spondylitis (AS). Previous studies have demonstrated a strong association between HLA-B27 gene and the pathogenesis of AS. In this study, 115 unrelated HLA-B27-positive AS patients and 119 HLA-B27-positive healthy controls were recruited. Polymerase chain reaction using sequence-specific primers was used to determine the genotypes of KIR genes and HLA-C alleles. The results showed that the frequencies of KIR2DL1 and KIR2DL5 were significantly higher in the AS patient group than those in the control group (p = 0.012 and p = 0.009, respectively). Meanwhile, individuals with AS showed an increased frequency of HLA-Cw*08 (p = 0.001, pc  = 0.008) compared with that in controls. Our findings indicate that with the genetic background of HLA-B27, variation at the KIRs and their corresponding specific HLA-C ligands may influence the ability of NK cells and T cells to recognize and lyse targets in immune responses, which thereby contributes to pathogenesis of AS.

Inhibitory KIR and specific HLA-C gene combinations confer susceptibility to or protection against chronic hepatitis B.

Antiviral activity of natural killer (NK) cells is regulated partially through inhibitory and activating killer cell immunoglobulin-like receptors (KIR) interacting with human leukocyte antigen C (HLA-C) ligands. The highly polymorphic nature of HLA-C and KIR genes endows individuals with diverse HLA-C/KIR combinations, which may confer susceptibility to or protection against a certain challenge. We analyzed the genes encoding KIR receptors and HLA-C ligands and HLA-C/KIR combinations in patients with chronic hepatitis B and healthy subjects. We found that inhibitory receptor KIR2DL1 in combination with HLA-C2 ligand confers susceptibility to chronic hepatitis B (CHB), whereas inhibitory receptor KIR2DL3 or KIR2DL3 homozygote in the presence of HLA-C1C1 genotype shows protection against CHB. Our data reveal that inhibitory NK cell interactions are important in determining antiviral immunity and that distinct affinity inhibitory responses will exert different impact on the development of CHB.

Immune complexes activate human endothelium involving the cell-signaling HMGB1-RAGE axis in the pathogenesis of lupus vasculitis.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the formation of immune complexes (ICs), which contain a complex mixture of autoantigens nucleic acids, nucleic acids-associated proteins and corresponding autoantibodies. In SLE, ICs are deposited in multiple organs. Vasculopathy and vasculitis in SLE are typical complications and are associated with deposition of ICs on endothelium, endothelial activation and inflammatory cell infiltration. However, the effects of ICs on endothelial cells and the mechanisms involved remain unclear. In this study, we have demonstrated for the first time that ICs upregulated cell surface expression of the receptor for advanced glycation end products (RAGE), the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), increased the secretion of the chemokines interleukin 8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), the proinflammatoy cytokines interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and promoted the activation of the transcription factor NF-κB p65 in human endothelial cells (P<0.05). ICs also increased transendothelial migration of monocytes (P<0.05). One of the mechanisms underlying these activating effects of ICs on human endothelial cells involves cell signaling by high-mobility group box 1 protein (HMGB1)-RAGE axis, as these effects can be partially blocked by HMGB1 A-box, soluble RAGE (sRAGE), SB203580, PD98059, Bay 117082 (P<0.05) and co-treatment with these agents (P<0.05). In conclusion, ICs elicit proinflammatory responses in human endothelial cells and alter their function involving cellular signaling via the HMGB1-RAGE axis in the pathogenesis of SLE vasculitis.

Association of KIR Genotypes and Haplotypes with Susceptibility to Chronic Hepatitis B Virus Infection in Chinese Han Population

Killer immunoglobulin-like receptor (KIR) genes can regulate the activation of NK and T cells upon interaction with HLA class I molecules. Hepatitis B virus (HBV) infection has been regarded as a multi-factorial disorder disease. Previous studies revealed that KIRs were involved in HCV and HIV infection or clearance. The aim of this study was to explore the possibility of the inheritance of KIR genotypes and haplotypes as a candidate for susceptibility to persistent HBV infection or HBV clearance. The sequence specific primer polymerase chain reaction (SSP-PCR) was employed to identify the KIR genes and pseudogenes in 150 chronic hepatitis B (CHB) patients, 251 spontaneously recovered (SR) controls, and 412 healthy controls. The frequencies of genotype G, M, FZ1 increased in CHB patients compared with healthy control subjects. The frequency of genotype AH was higher in SR controls than that in both CHB patients and healthy controls. The carriage frequencies of genotype G and AH were higher; while, the frequencies of AF and AJ were lower in SR controls than those in healthy control subjects. The frequency of A haplotype was lower, whereas, the frequency of B haplotype was higher in CHB patients and SR controls than those in healthy controls. In healthy controls, haplotype 4 was found lower compared with that in CHB patients and SR controls and the frequency of haplotype 5 was higher in SR controls than that in other two groups. Based on these findings, it seems that the genotypes M and FZ1 are HBV susceptive genotypes; AH, on the other hand, may be protective genotypes that facilitate the clearance of HBV. It appears that the haplotype 4 is HBV susceptive haplotype, whereas, haplotype 5 may be the protective haplotype that facilitates the clearance of HBV.

Family-based analysis of susceptibility loci for polycystic ovary syndrome on chromosome 2p16.3, 2p21 and 9q33.3

BACKGROUND Polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder. A previous genome-wide association study (GWAS) identified five single nucleotide polymorphisms (SNPs) which were independently associated with PCOS in Han Chinese. To overcome population stratification, a family-based analysis was conducted to validate whether these five SNPs are associated with PCOS. METHODS A total of 276 family trios (828 participants) having a proband with PCOS were included in the family-based study. The transmission disequilibrium test (TDT) was used to analyze the association between PCOS and five SNPs rs13429458, rs12478601, rs13405728, rs10818854 and rs2479106 in three susceptible loci 2p16.3, 2p21 and 9q33.3. RESULTS A positive association was observed for the SNP rs13429458 (P= 3.74 × 10(-5)). CONCLUSIONS TDT confirms that SNP rs13429458, in the THADA gene, is significantly associated with risk of PCOS. This family-based analysis enhances our previous case-control GWAS and provides further support for the role of susceptibility loci in PCOS.

Disparate distribution of activating and inhibitory killer cell immunoglobulin-like receptor genes in patients with systemic lupus erythematosus

The genes of killer cell immunoglobulin-like receptors (KIRs), which are involved in the activation of T cells and natural killer cells, are highly variable. In recent years, the role of KIRs in autoimmune diseases has received increasing attention. The present study was undertaken to determine the association of the polymorphism of KIR genes with the susceptibility to systemic lupus erythematosus (SLE). The polymorphism of KIR genes of 93 patients with SLE together with 123 healthy donors as the control group was determined by polymerase chain reaction with sequence-specific primers. Twenty-seven novel gene combinations were found. Genotypic frequencies of KIR2DL2 (p < 0.001) and KIR2DS1 (p < 0.001) were much higher in patients with SLE than in control subjects. Individuals with two and more than two activating KIR genes were found more frequently in patients than in control subjects (80.7% versus 66.7%, p = 0.022). The results suggest that a genetic disturbance between activating and inhibitory KIR genes may be one of the key factors underlying the pathogenesis of SLE.