Zhimin Miao

Genetic analysis of ABCG2 gene C421A polymorphism with gout disease in Chinese Han male population

Gout is the most frequent inXammatory joint disease in men above 40 years of age (Luk and Simkin 2005). Recently, a genome-wide association study identiWed substantial associations between single nucleotide polymorphism (SNPs), rs2231142, in the ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2) and uric acid concentration and gout in both white and black individuals and may be a causal candidate variant (Dehghan et al. 2008). To clarify the global relevance of the variant rs2231142 (c. C421A), the association needs to be conWrmed by independent studies in diVerent ethnic groups. The objective of this study is to assess the genetic association of SNP in ABCG2 gene with gout in a Chinese Han male population. A total of 200 gout patients and 235 gout-free control were recruited in this study from Qingdao University. The diagnosis of gout was based on the preliminary criteria which was published by the American College of Rheumatology in 1977 for the classiWcation of gout for use in either clinical settings or population-based epidemiologic studies (Wallace et al. 1977). The rs2231142 and nearby regions were ampliWed by polymerase chain reaction (PCR) (PCR primers were shown on supplementary Table 1) and PCR product was sequenced by ABI 3730XL (Applied Biosystems, Foster City, CA) to perform mutational analysis. The associations between biochemical data and gout are listed in Table 1. There were signiWcant diVerence in rs2231142 genotypic and allelic frequencies between gout cases and controls (shown in Table 2). Compared with controls, there was a higher A/A genotype and A allele frequency of rs2231142 in the gout cases (21.8 vs. 8.4% by genotype; 44.9 vs. 32.3% by allele). And the association to gout reached signiWcance ( 2 = 15.91, P < 0.001, crude OR = 3.02, 95% CI 1.36–4.90 and OR (adjusted by age) = 1.80, 95% CI 1.32–2.45 by dominant mode; 2 = 6.82, P = 0.009, OR = 1.67 95% CI 1.54–2.27 by recessive mode). Compared with C/C genotype carriers, there was higher uric acid level in A allele carriers in the gout cases. However, the diVerence did not reach signiWcance (P = 0.066). Rs2231142, the missense SNP in ABCG2 (Q141 K) was associated with uric acid concentration and gout in both white and black individuals and may be a causal candidate variant also for Chinese Han people. The eVects of the polymorphism on the functions of ABCG2 in vitro have been revealed using transfectants that the individuals with the C/C genotype are presumed to have the highest transporter activity (Imai et al. 2002; Kondo et al. 2004; Mizuarai et al. 2004; Woodward et al. 2009). C421A also aVects the B. Wang and Z. Miao contributed equally to the work.

Association of the T1799A BRAF mutation with tumor extrathyroidal invasion, higher peripheral platelet counts, and over- expression of platelet-derived growth factor-B in papillary thyroid cancer

The relationship among BRAF mutation, platelet counts, and platelet-derived growth factor (PDGF) with respect to clinicopathological outcomes of papillary thyroid cancer (PTC) may play a role in PTC pathogenesis but remains undefined. We examined the T1799A BRAF mutation by direct genomic DNA sequencing in 108 primary PTC samples from a Chinese cohort and analyzed its relationship with clinicopathological, hematological, and other laboratory results as well as the levels of expression of PDGF in tumors. We found that the BRAF mutation was significantly associated with extrathyroidal invasion and advanced tumor stages III and IV. Specifically, extrathyroidal invasion was seen in 30/54 (56%) PTC with BRAF mutation versus 18/54 (33%) PTC without the mutation (P=0.02). Tumor stages III and IV were seen in 16/54 (30%) PTC with BRAF mutation versus 7/54 (13%) PTC without the mutation (P=0.04). The BRAF mutation was also significantly associated with a higher platelet count, with 249.28+/-53.76 x 10(9)/l in the group of patients with BRAF mutation versus 207.79+/-58.98 x 10(9)/l in the group without the mutation (P=0.001). An association of higher platelet accounts with extrathyroidal invasion was also seen, with 242.66+/-51.85 x 10(9)/l in patients with extrathyroidal invasion versus 218.49+/-59.10 x 10(9)/l in patients without extrathyroidal invasion (P=0.03). The BRAF T1799A-positive PTC tissues harbored a significantly higher level of PDGF-B than BRAF T1799A-negative PTC tissues. The data suggest that the BRAF T1799A mutation is associated with aggressive pathological outcomes of PTC in which high platelet counts and increased PDGF production may play a role.

Multiple single nucleotide polymorphisms in the human urate transporter 1 (hURAT1) gene are associated with hyperuricaemia in Han Chinese

Objective The present study investigated whether single nucleotide polymorphisms (SNPs) in the human urate transporter 1 (hURAT1) gene are associated with primary hyperuricaemia (HUA) in Han Chinese people. Methods A total of 538 subjects (215 cases and 323 control subjects) were recruited from Qingdao, China. SNPs in potentially functional regions of the gene were identified and genotypes determined by direct sequencing. Association analyses were conducted using Fishers exact test and logistic regression assuming a genotype model. Results By sequencing the promoter, 10 exons, and the exon-intron junctions of the hURAT1 gene, 14 SNPs were identified. Two of the SNPs identified were associated with susceptibility to HUA. The first was a rare intron 3 (11 G→A) SNP (p=0.0005), where carriers of the ‘A’ allele had a 3.4-fold (95% CI 1.67 to 6.93) increased risk of HUA. The second was a common exon 8 (T1309C) SNP (rs7932775), where carriers of one and two ‘C’ alleles had respective fold increased risks of 1.64 (95% CI 1.07 to 2.52) and 2.32 (95% CI 1.37 to 3.95). These SNPs had a joint additive effect of risk of HUA, with those individuals carrying at least one ‘A’ allele at the intron 3 SNP and two ‘C’ alleles at rs7932775 having a 5.88-fold (95% CI 1.25 to 15.57) increased risk of HUA in comparison to those with no risk alleles. Conclusion In conjunction with other studies, our results suggest that there are multiple genetic variants within or near hURAT1 that are associated with susceptibility to HUA in Han Chinese, including a novel SNP located in intron 3.

Polymorphisms in the Presumptive Promoter Region of the SLC2A9 Gene Are Associated with Gout in a Chinese Male Population

Background Glucose transporter 9 (GLUT9) is a high-capacity/low-affinity urate transporter. To date, several recent genome-wide association studies (GWAS) and follow-up studies have identified genetic variants of SLC2A9 associated with urate concentrations and susceptibility to gout. We therefore investigated associations between gout and polymorphisms and haplotypes in the presumptive promoter region of GLUT9 in Chinese males. Methodology/Principal Findings The approximately 2000 bp presumptive promoter region upstream of the start site of exon 1 of GLUT9 was sequenced and subjected to genetic analysis. A genotype-phenotype correlation was performed and polymorphisms-induced changes in transcription factor binding sites were predicted. Of 21 SNPs identified in GLUT9, five had not been previously reported. Two of the SNPs (rs13124007 and rs6850166) were associated with susceptibility to gout (p = 0.009 and p = 0.042, respectively). The C allele of rs13124007 appeared to be the risk allele for predisposition to gout (p = 0.006, OR 1.709 [95% CI 1.162–2.514]). For rs6850166, an increased risk of gout was associated with the A allele (p = 0.029, OR 1.645 [95% CI 1.050–2.577]). After Bonferroni correction, there was statistically difference in rs13124007 allele frequencies between gout cases and controls (P = 0.042). Haplotype analyses showed that haplotype GG was a protective haplotype (p = 0.0053) and haplotype CA was associated with increased risk of gout (p = 0.0326). Genotype-phenotype analysis among gout patients revealed an association of rs13124007 with serum triglycerides levels (P = 0.001). The C to G substitution in polymorphism rs13124007 resulted in a loss of a binding site for transcription factor interferon regulatory factor 1 (IRF-1). Conclusions/Significance Polymorphisms rs13124007 and rs6850166 are associated with susceptibility to gout in Chinese males.

Genetic analysis of the ELOVL6 gene polymorphism associated with type 2 diabetes mellitus

Recent animal studies have indicated that overexpression of the elongation of long-chain fatty acids family member 6 (Elovl6) gene can cause insulin resistance and β-cell dysfunction. These are the major factors involved in the development of type 2 diabetes mellitus (T2DM). To identify the relationship between single nucleotide polymorphisms (SNP) of ELOVL6 and T2DM pathogenesis, we conducted a case-control study of 610 Han Chinese individuals (328 newly diagnosed T2DM and 282 healthy subjects). Insulin resistance and islet first-phase secretion function were evaluated by assessment of insulin resistance in a homeostasis model (HOMA-IR) and an arginine stimulation test. Three SNPs of the ELOVL6 gene were genotyped with polymerase chain reaction-restriction fragment length polymorphism, with DNA sequencing used to confirm the results. Only genotypes TT and CT of the ELOVL6 SNP rs12504538 were detected in the samples. Genotype CC was not observed. The T2DM group had a higher frequency of the C allele and the CT genotype than the control group. Subjects with the CT genotype had higher HOMA-IR values than those with the TT genotype. In addition, no statistical significance was observed between the genotype and allele frequencies of the control and T2DM groups for SNPs rs17041272 and rs6824447. The study indicated that the ELOVL6 gene polymorphism rs12504538 is associated with an increased risk of T2DM, because it causes an increase in insulin resistance.

The Lipid-Bound Apolipoprotein A-I Cysteine Mutant (N74C) Inhibits the Activation of NF-κB, JNK and p38 in Endotoxemic Mice and RAW264.7 Cells

Our previous studies showed that recombinant high-density lipoprotein (rHDL) rHDL74 exhibited higher anti-inflammatory capabilities compared to wild-type rHDL (rHDLwt), while rHDL228 showed hyper-proinflammation. In this paper, we further investigated the potential mechanisms involved in their different inflammatory functions using two models: endotoxemic mice and the RAW264.7 inflammation model. Our results showed that 24 h after the injection of lipopolysaccharide (LPS), mice treated with rHDL74 had a significant decrease in plasma CRP (P<0.01 vs. rHDLwt; P<0.01 vs. LPS), MCP-1 (P<0.05 vs. rHDLwt; P<0.01 vs. LPS) and CD14 (P<0.01 vs. LPS) compared with the mice treated with rHDLwt or the controls that received LPS only. Similar to our previous study, rHDL228 increased the plasma level of CRP (P<0.05 vs. LPS) and MCP-1 (P<0.01 vs. LPS). Our immunohistochemistry and western blot analysis showed that rHDL74 inhibited the activation of NF-κB in endotoxemic mice and JNK and p38 in the RAW264.7 inflammation model, while rHDL228 exacerbated the activation of NF-κB and ERK. In summary, our data suggest that rHDL74 exhibits higher anti-inflammatory activity by decreasing inflammatory factors and inhibiting the activation of NF-κB, JNK and p38, while rHDL228 appears to be hyper-proinflammation by increasing these inflammatory factors and aggravating the activation of NF-κB and ERK.

Deletion of microRNA miR-146a does not prevent streptozotocin-induced murine autoimmune type 1 diabetes.

Diabetes & Metabolism - In Press.Proof corrected by the author Available online since mardi 26 avril 2016