ERBB3-rs2292239 as primary type 1 diabetes association locus among non-HLA genes in Chinese.

Type 1 diabetes (T1D) is an autoimmune disease that has strong contribution of genetic factors to its etiology. We aimed to assess the genetic association between non-HLA genes and T1D in a Chinese case-control cohort recruited from multiple centers consisting of 364 patients with T1D and 719 unrelated healthy children. We genotyped 55 single nucleotide polymorphisms (SNP) markers located in 16 non-HLA genes (VTCN1, PTPN22, CTLA4, SUMO4, CD274, IL2RA, INS, DHCR7, ERBB3, VDR, CYP27B1, CD69, CD276, PTPN2, UBASH3A, and IL2RB) using SNaPshot multiple single-base extension methods. After multivariate analysis and correction for multiple comparisons, we identified the SNP rs2292239 in ERBB3 gene were significantly associated with T1D. The frequency of the major G allele was significantly decreased in patients with T1D (68.8% in T1D vs 77.3% in controls, OR 0.65, 95% CI 0.53-0.79, P = 0.02), and the minor allele T was associated with an increased risk of T1D (OR 1.55, 95% CI 1.26-1.90, P = 0.02). Our haplotype analysis confirmed that rs2292239 was the primary T1D association locus in our current investigation. These results indicated that the ERBB3-rs2292239 was the primary T1D association locus among the investigated 55 SNPs in 16 non-HLA genes in Chinese Han population.

Relationship between initial treatment effect of recombinant human growth hormone and exon 3 polymorphism of growth hormone receptor in Chinese children with growth hormone deficiency.

The aim of this study is to investigate the frequency distribution of exon 3 deleted (d3-GHR) genetic polymorphism of growth hormone receptor (GHR) in growth hormone deficient (GHD) Chinese children and to explore the correlation between the growth promoting effects of recombinant human growth hormone (rhGH) and exon 3 genetic polymorphism of GHR in GHD children. In this study, 111 GHD (excluded small for gestational age) children were treated with rhGH (0.20 mg/kg/week) for six months. The body height (Ht), body weight, bone age (BA) and growth velocity (GV) were measured before and after six months of treatment. The d3-GHR and full length GHR (fl-GHR) were analyzed to detect the frequency distribution of two isoforms and their influence on growth promoting effect of rhGH. The results indicated that the frequencies of fl/fl, fl/d3 and d3/d3 GHR genotypes were 67.6%, 18.9% and 13.5%. After six months of GH therapy, there were significant differences of ΔGV (ΔGV: 10.77±3.40 cm/year vs 12.18±3.08 cm/year) (P<0.05) and ΔHt (ΔHt: 5.38±1.70 cm vs 6.09±1.54 cm) (P<0.05) were found among GHD children with different genotypes (fl/fl vs fl/d3 and d3/d3). In conclusion, the frequency distribution of three GHR genotypes in 111 Chinese GHD children was different from that reported in Caucasian, indicating the existence of ethnic difference of exon 3 GHR polymorphism. There was a closely relationship between GHR genotypes and growth-promoting effect of rhGH in Chinese GHD children.

SNPs in the exons of Toll-like receptors are associated with susceptibility to type 1 diabetes in Chinese population.

OBJECTIVE: Toll-like receptors (TLRs) recognize a wide range of pathogen-associated molecular patterns (PAMP) and mount the initiation of immune response. Single nucleotide polymorphisms (SNPs) in exons of genes encoding TLRs might be responsible for the generation of an abnormal immune response which could lead to autoimmune diseases. In this study, we investigated the SNPs in TLRs in a Chinese population, and we hypothesized that SNPs in TLRs are associated with type 1 diabetes (T1D), an autoimmune disease caused by destruction of insulin producing pancreatic ß-cells, in the studied population. RESEARCH DESIGN AND METHODS: We selected 28 SNPs in exons of TLRs with an aim to identify those that might have a direct correlation with T1D etiology and many have not been included in previous GWAS studies. Genotyping of those SNPs in TLRs was performed in 429 T1D patients and 300 age and gender-matched healthy controls in Chinese Han population which was not included in the earlier GWAS studies. RESULTS: Among the SNPs genotyped, the T allele of TLR1-626 was positively associated with T1D (OR=1.98, Pc=0.01). We identified another T1D association locus in TLR6: the homozygous AA genotype of TLR6-1329 was negatively and heterozygous GA was positively associated with T1D (OR=0.54, Pc=0.02 and OR=1.70, Pc=0.03, respectively). We also identified the haplotype T-G-A in TLR1 gene to be positively associated with T1D (OR=2.22, Pc=0.03). Additional haplotypes in TLR-6 also showed significant positive and negative association. In addition, our haplotype analysis and conditional analysis showed that these two SNPs are the primary T1D associated loci among the SNPs tested in our cohort in each TLR gene. CONCLUSION: SNPs and haplotypes in TLR1 and TLR6 gene were associated with T1D in Chinese Han population. Our study, for the first time, indicates that TLR1 and TLR6 gene might play important roles in the etiology of T1D.

Rapidly rising incidence of childhood type 1 diabetes in Chinese population: epidemiology in Shanghai during 1997-2011.

The aim of this study was to investigate incidence trend of childhood type 1 diabetes in Shanghai, a megalopolis in east China. We established a population-based retrospective registry for the disease in the city's registered population during 1997-2011 and collected 622 incident type 1 diabetes in children aged 0-14 years. Standardized incidence rates and 95 % CI were estimated by applying the capture-recapture method and assuming Poisson distribution. Incidence trend was analyzed using the Poisson regression model. The mean annual incidence of childhood type 1 diabetes was 3.1 per 100,000 person-years. We did not observe significant difference in incidence between boys and girls. The incidence is unstable and had a mean annual increase 14.2 % per year during the studied period. A faster annual increase was observed in boys, warmer seasons, and in the outer regions of the city. If present trends continue, the number of new type 1 diabetes cases will double from 2016 to 2020, and prevalent cases will sextuple by 2025. Our results showed the incidence of childhood type 1 diabetes was rising rapidly in Shanghai. More studies are needed to analyze incidence changes in other regions of China for appropriate allocation of healthcare resources.

[Protective effect of cotransfection of A20 and HO-1 gene against the apoptosis induced by TNF-α in rat islets in vitro].

OBJECTIVE: To establish the method for cotransferring human A20 gene and human heme oxygenase-1 (HO-1) gene into the isolated rat islets using lentiviral transfection system, and to study the protective effect of A20 and HO-1 protein against the apoptosis induced by cycloheximide (CHX) and TNF-α, and finally to explore the underlying mechanism. METHOD: The A20 gene and HO-1 gene were cloned and inserted into the lentiviral transfection system. The efficacy of gene transfer was measured by the intensity of the enhanced green fluorescent protein (EGFP) fluorescence-positive islets. Western blot was applied to verify the expression of the A20 and HO-1 genes. To induce apoptosis in vitro, the isolated islets were treated with CHX+TNF-α, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and the fluorescence-activated cell sorting (FACS) methods were used to evaluate the apoptosis of the islet cells and Western blot was used to detect caspase-3 activation. RESULT: (1) A20 and HO-1 genes were introduced into the isolated islets by lentiviral transfection, both of the genes were highly expressed in the islets after 96 hours culture detected by Western blot method. (2) The insulin levels in the cell culture medium from A20 and/or HO-1 transgenic islets were significantly higher than that in non-transgenic controls (P < 0.01). (3)After CHX + TNF-alpha treatment, the cell culture medium insulin concentration in the A20 gene transfected group [(93.58 ± 4.12)µg/ml], HO-1 gene transfected group [(88.98 ± 4.77) µg/ml ] and A20/HO-1 co-transfected group [(103.33 ± 3.16) µg/ml] were significantly higher than that in the EGFP group [(9.03 ± 0.65) µg/ml ] and the control group [(8.86 ± 0.38) µg/ml] (P < 0.001). Minimum expression level of the activated caspase-3 was found in the A20/HO-1 co-transfected group. CONCLUSION: The lentiviral gene transfer system was an efficient and stable gene transfer vector, the over-expressed A20 and HO-1 protein delivered via lentivirus could preserve rats' islets function and act against the apoptosis induced by CHX and TNF-α.

[The establishment of "two-step sequential filtration method" on the yield rate of purified islets in rats].

OBJECTIVE: To develop a simple, rapid and reliable method of purifying Sprague-Dawley (SD) rat islets by sequential filtration through two cell strainers of different sizes and to evaluate the efficacy of the method. METHODS: Islets were isolated from 8 to 12-week-old clean grade Sprague-Dawley rat pancreases using the standard collagenase digestion procedure and purified with either the generally used Ficoll density gradient method or the innovative two-step sequential filtration method. The purity and vitality of the isolated islets were visualized and assessed with DTZ and AO/PI staining. Glucose stimulating tests were performed to assay cell activity, and immunohistochemical staining was used to evaluate the synthesis function of islet cells. RESULTS: The yield of islets in the two-step filtration method group was 782±115 IEQ per rat, which was significantly higher than in the conventional Ficoll density gradient method group (598 ± 135 IEQ per rat, P < 0.01). Purity of the isolated islets in the two-step filtration method group was 90%-100% and vitality was over 95%. In the conventional Ficoll density gradient method group, islet purity was 65%-85% and vitality was 85%-95%. With regard to the high-sugar stimulation test in the two-step filtration method group, insulin concentrations in islets cultured for 24 hours were significantly higher than in those that were freshly purified (76.9 ± 6.1 µg/L vs 49.4 ± 3.9 µg/L; P < 0.01). CONCLUSIONS: A two-step sequential filtration method for rat islet purification was developed and the method was simple and reliable, with high islet vitality, purity and yield.

Killer cell immunoglobulin-like receptor along with HLA-C ligand genes are associated with type 1 diabetes in Chinese Han population.

OBJECTIVE: Killer cell immunoglobulin-like receptor (KIR) genes and their putative ligands human leukocyte antigen (HLA)-C genes have been associated with type 1 diabetes (T1D). We hypothesize that KIR genes and their ligands HLA-C genes are important in T1D aetiology. RESEARCH DESIGN AND METHODS: KIR and HLA-C ligand genotyping was performed in 259 T1D patients and 262 healthy children. RESULTS: No significant difference was observed in the distribution of KIR genes between T1D patients and healthy controls. However, frequency of HLA-C1 gene and HLA-C2 gene (marginal association) was higher in patient group. The combinations 2DL2-/HLA-C1+; 2DL3+/HLA-C1+; 2DS2-/HLAC1+ were positively associated with T1D. The combinations 2DL1+/HLA-C2-; 2DL2-/HLA-C1-; 2DL3+/HLA-C1-; 2DS2-/HLAC1- were found to be negatively associated with T1D. Among the genes we tested, a combination of HLA-C1 and -C2 conferred the strongest association with T1D and the strength of this association was higher than that of HLA-C1 alone. The frequencies of KIR 2DL1, 2DL2 and 2DL3 and HLA-C1 were higher in T1D patients positive for GAD65 autoantibody; frequency of KIR 2DS4 is higher in T1D patients positive for IA-2 autoantibody. The association between KIR/HLA-C gene and autoantibody status was not statistically significant after applying Bonferroni correction. CONCLUSION: In our study of a Han population (East China), we found no direct association of KIR genes with T1D. However, a combination of HLA-C1 and -C2 showed a positive association with T1D. Different combinations of HLA-C and KIR showed positive and negative association with T1D.

The growth hormone receptor (GHR) exon 3 polymorphism and its correlation with metabolic profiles in obese Chinese children.

OBJECTIVE: We investigated the correlation between the growth hormone receptor (GHR) exon 3 polymorphism and the metabolic profiles of Chinese children with obesity. SUBJECTS AND METHODS: A total of 409 obese/overweight children and 206 normal weight children were recruited. Anthropological and biochemical indexes including insulin and lipid profiles were measured. Genomic DNA was extracted from the peripheral blood leukocytes, and the GHR exon 3 polymorphism was genotyped by polymerase chain reaction. Homeostasis model of assessment for insulin resistance index (HOMA-IR) and insulin sensitivity index (ISI) were calculated using the homeostasis model. RESULTS: The frequency of the exon 3-deleted GHR (d3-GHR) polymorphism within the obese group was significantly higher than that of the control group (p < 0.05). Body mass index (BMI), fasting insulin (FIns), HOMA-IR, total cholesterol, and triglycerides were significantly lower in the d3-GHR (d3/d3 and d3/fl) group than in the full-length GHR (fl/fl, fl-GHR) group (p < 0.05). After adjustment for BMI, cholesterol level was still significantly lower and HOMA-IR was marginally lower (p = 0.079) in the d3-GHR obese group. There was no statistically significant difference in BMI, FIns, HOMA-IR, ISI, total cholesterol, or triglyceride levels between the two genotypes in the control group. CONCLUSION: We report that the d3-GHR polymorphism has a significant effect on BMI and the metabolic parameters of Chinese children with obesity. The d3 allele may have a protective effect on the development of metabolic syndrome by increasing insulin sensitivity.

Novel BSCL2 gene mutation E189X in Chinese congenital generalized lipodystrophy child with early onset diabetes mellitus.

CONTEXT: Congenital generalized lipodystrophy (CGL) is a rare and heterogeneous disease of autosomal recessive inheritance. Until now, no genetic findings had been reported in Chinese patients with CGL. OBJECTIVE: To analyze Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) and 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2) gene variation in a Chinese boy with CGL and his family. DESIGN, SETTING, AND PARTICIPANTS: All exons of BSCL2 and AGPAT2 with adjacent intron-exon junctions were analyzed using direct sequencing. MAIN OUTCOME MEASURES: Sequences of each exon and nearby intron of the BSCL2 and AGPAT2 genes of the family members were compared with the gene bank genomic sequences. RESULTS: DNA sequence analysis of the entire coding regions and surrounding uncoding regions disclosed a novel homozygous G-->T mutation at nucleotide 909 in exon 5 of the BSCL2 gene in the affected child. A heterozygous state of the G-->T mutation of the BSCL2 gene was also found in other family members. This mutation predicts the substitution of glutamic acid at codon 189 by the stop codon (Glu189X or E189X). No variation was found in the AGPAT2 gene. Conclusion E189X is a novel BSCL2 gene mutation that contributes to CGL formation in a family of Chinese origin.