👤 Yukitoshi Aoyagi

Gout is a common type of acute arthritis that results from elevated serum uric acid (SUA) levels. Recent genome-wide association studies (GWASs) have revealed several novel single nucleotide polymorphism (SNPs) associated with SUA levels. Of these, rs10821905 of A1CF and rs1178977 of BAZ1B showed the greatest and the second greatest significant effect size for increasing SUA level in the Japanese population, but their association with gout is not clear. We examined their association with gout using 1411 clinically-defined Japanese gout patients and 1285 controls, and meta-analyzed our previous gout GWAS data to investigate any association with gout. Replication studies revealed both SNPs to be significantly associated with gout (P = 0.0366, odds ratio [OR] with 95% confidence interval [CI]: 1.30 [1.02-1.68] for rs10821905 of A1CF, P = 6.49 × 10 Show less

We previously showed that the -1131T→C polymorphism (rs662799) of the apolipoprotein A-V gene (APOA5) and the C→T polymorphism (rs6929846) of the butyrophilin, subfamily 2, member A1 gene (BTN2A1) were significantly associated with an increased serum concentration of triglycerides, a decreased serum concentration of high density lipoprotein (HDL)-cholesterol, and the prevalence of metabolic syndrome (MetS) in Japanese individuals. The purpose of the present study was to examine whether these polymorphisms synergistically affect the prevalence of dyslipidemia and MetS in East Asian populations. The study populations comprised 7471 Japanese and 3529 Korean individuals in the dyslipidemia study, and 3474 Japanese and 1671 Korean individuals in the MetS study. Multivariable logistic regression analysis of combined genotypes with adjustment for age, gender and diabetes mellitus revealed that rs662799 and rs6929846 significantly and synergistically affected dyslipidemia. Japanese or Korean individuals with the C allele of APOA5 and the T allele of BTN2A1 had a 2.05- or 1.92-fold increased risk for hypertriglyceridemia and a 1.82- or 1.56-fold increased risk for hypo-HDL-cholesterolemia, respectively, compared to those with the TT genotype of APOA5 and the CC genotype of BTN2A1. Similar analysis with adjustment for age and gender revealed that Japanese individuals, but not Korean individuals, with the C allele of APOA5 and the T allele of BTN2A1 had a 2.87-fold increased risk for MetS compared to those with the TT genotype of APOA5 and the CC genotype of BTN2A1. Genetic variants of APOA5 and BTN2A1 may synergistically affect the prevalence of dyslipidemia in East Asian populations and of MetS in Japanese individuals. Show less

The aetiology of metabolic syndrome is complex, being determined by the interplay of both genetic and environmental factors. The aim of this study was to identify genetic polymorphisms that confer susceptibility to metabolic syndrome, to allow prediction of genetic risk for this condition. The study population comprised 2417 unrelated Japanese subjects (1522 with metabolic syndrome and 895 controls). The genotypes for 44 polymorphisms of 31 candidate genes related to lipid metabolism were determined using a combination of PCR and sequence-specific oligonucleotide probes with suspension array technology. The chi(2) test and subsequent multivariate logistic regression analysis with adjustment for age, sex and smoking status found that the-3A-->G and 553G-->T (Gly185Cys) polymorphisms of APOA5, the 2052T-->C (Val653Val) and 1866C-->T (Asn591Asn) polymorphisms of LDLR, the 13989A-->G (Ile118Val) polymorphism of CYP3A4 and the 1014T-->A polymorphism of C1QTNF5 were significantly (false discovery rate <0.05) associated with the prevalence of metabolic syndrome, with the variant alleles of APOA5 and C1QTNF5 representing risk factors for and those of LDLR and CYP3A4 being protective against this condition. Serum levels of triglycerides and high-density lipoprotein (HDL) cholesterol differed significantly (p<0.05) among APOA5 genotypes; the serum level of HDL cholesterol differed among LDLR genotypes; and the fasting plasma glucose level and body mass index differed between CYP3A4 and C1QTNF5 genotypes, respectively. APOA5, LDLR, CYP3A4 and C1QTNF5 are susceptibility loci for metabolic syndrome in Japanese people. Genotypes for these polymorphisms may prove informative for prediction of genetic risk for metabolic syndrome. Show less

Voltage-gated cation channels regulate neuronal excitability through selective ion flux. NALCN, a member of a protein family that is structurally related to the alpha1 subunits of voltage-gated sodium/calcium channels, was recently shown to regulate the resting membrane potentials by mediating sodium leak and the firing of mouse neurons. We identified a role for the Caenorhabditis elegans NALCN homologues NCA-1 and NCA-2 in the propagation of neuronal activity from cell bodies to synapses. Loss of NCA activities leads to reduced synaptic transmission at neuromuscular junctions and frequent halting in locomotion. In vivo calcium imaging experiments further indicate that while calcium influx in the cell bodies of egg-laying motorneurons is unaffected by altered NCA activity, synaptic calcium transients are significantly reduced in nca loss-of-function mutants and increased in nca gain-of-function mutants. NCA-1 localizes along axons and is enriched at nonsynaptic regions. Its localization and function depend on UNC-79, and UNC-80, a novel conserved protein that is also enriched at nonsynaptic regions. We propose that NCA-1 and UNC-80 regulate neuronal activity at least in part by transmitting depolarization signals to synapses in C. elegans neurons. Show less

The purpose of the present study was to identify genetic variants that confer susceptibility to dyslipidemia. A total of 5213 individuals from two independent populations were examined: Subject panel A comprised 3794 individuals who visited participating hospitals; subject panel B comprised 1419 community-dwelling elderly individuals. The genotypes for 100 polymorphisms of 65 candidate genes were determined. The chi(2) test and multivariable logistic regression analysis revealed that seven polymorphisms of APOA5, APOC3, APOA1, ACAT2, and LPL were significantly associated with hypertriglyceridemia, six polymorphisms of APOA5, LIPC, and CYP3A4 with low HDL-cholesterol, and three polymorphisms of APOE and CCR2 with high LDL-cholesterol in subject panel A. For validation of these associations, the same polymorphisms were examined in subject panel B. Six polymorphisms of APOA5, APOC3, APOA1, and LPL were again significantly associated with hypertriglyceridemia, three polymorphisms of APOA5 with low HDL-cholesterol, and two polymorphisms of APOE with high LDL-cholesterol. Serum triglyceride, HDL-cholesterol, and LDL-cholesterol concentrations differed significantly among genotypes of these corresponding polymorphisms in both subject panels. These results indicate that polymorphisms of APOA5, APOC3, APOA1, and LPL are determinants of hypertriglyceridemia and that those of APOA5 and APOE are determinants of low HDL-cholesterol and high LDL-cholesterol, respectively, in Japanese individuals. Show less