Humans ; Diabetes Mellitus, Type 2/genetics* ; Hyperlipidemias ; Mutation ; Insulin Resistance/genetics* ; Metabolic Diseases ; Proto-Oncogene Proteins c-akt ; Perilipin-1/genetics*

Insulinoma-associated protein-2 (IA-2) is a transmembrane glycoprotein belonging to the tyrosine phosphatase-like protein family as well as an important autoantigen in the diagnosis of type 1 diabetes. IA-2 products have been marketed in Europe and the United States. At present, commercially available IA-2 antigens are either the recombinant IA-2ic domain or the IA-2 naturally extracted from bovine islets. However, the recombinant IA-2 antigen displays weak positive in clinic practice, which often results in occasional detection failures, thus cannot completely replace the naturally extracted IA-2 antigen. In this study, an HEK293 expression system was used to explore the production of recombinant IA-2. An IA-2 transmembrane fragment (IA-2 TMF) located at amino acid position 449-979, also known as the natural membrane protein form of IA-2, was produced in HEK293 through transfection, and both the expression conditions and dissolution conditions of the membrane protein were also optimized. The purified membrane protein yield was 0.78 mg/L cell culture. Subsequently, the antigen activity of IA-2 TMF was compared with RSR rhIA-2 through enzyme linked immunosorbent assay. The serum of 77 type 1 diabetes patients and 32 healthy volunteers were detected. Receiver operating characteristic curve (ROC) curve was used to characterize the sensitivity and specificity of the test results. The results showed that the sensitivity of IA-2 TMF was 71.4% (55/77), while the sensitivity of RSR rhIA-2 was 63.6% (49/77), and the specificity of both antigens were all 100%. There was no significant difference in specificity between the two antigens, but the sensitivity of IA-2 TMF was appreciably better than that of the imported gold standard RSR rhIA-2 antigen. In conclusion, the recombinant IA-2 TMF produced in HEK293 cells can be used as a raw material to develop in vitro diagnostic reagents for type 1 diabetes.
Humans ; Animals ; Cattle ; HEK293 Cells ; Insulinoma ; Diabetes Mellitus, Type 1/genetics* ; Recombinant Proteins ; Membrane Proteins ; Pancreatic Neoplasms

Zinc transporter 8 (ZnT8) is an important candidate antigen for type Ⅰ diabetes. The autoantibody detection kit based on ZnT8 can be used to help diagnose type Ⅰ diabetes, and the related products have been launched in Europe and the United States. Since the recombinant production system of active ZnT8 has not been established in China, this key raw material is heavily dependent on imports. We used Saccharomyces cerevisiae to carry out the recombinant expression of ZnT8. First, multiple antigenic forms of ZnT8 were designed as C-terminal haploid (C), C-terminal diploid (C-C), and N-terminal and C-terminal concatemers (N-C). The proteins were expressed, purified and tested for antigenicity by bridging-type ELISA. The serum of 13 patients with type Ⅰ diabetes and the serum of 16 healthy volunteers were detected. C, N-C, and C-C proteins had similar detection rates, which were 53.8% (7/13), 61.5% (8/13) and 53.8% (7/13). The specificity of the three groups was 100% (16/16). The detection value on positive samples P3, P4, and P8 increased by more than 90%, indicating better serum antibody recognition ability. Finally, N-C protein was selected for further serum sample testing, and the test results were characterized by receiver operating characteristic (ROC) curve for sensitivity and specificity. Compared with imported gold standard antigen, the sensitivity was 76.9% (10/13) and the specificity was 87.5% (14/16). There was no significant difference in the sensitivity of the method, but the specificity needed to be improved. In conclusion, the ZnT8 N-terminal and C-terminal concatemer protein developed based on S. cerevisiae expression system is expected to be a key alternative raw material in the development of in vitro diagnostic reagents for type Ⅰ diabetes.
Antigens ; Autoantibodies ; Diabetes Mellitus, Type 1/diagnosis* ; Enzyme-Linked Immunosorbent Assay ; Humans ; Saccharomyces cerevisiae/genetics* ; Zinc Transporter 8/genetics*

OBJECTIVE: To report on the clinical features and result of genetic testing for a child featuring immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. METHODS: Clinical records, genetic testing, laboratory investigation and treatment of the child were summarized in addition with a comprehensive review of the literature. RESULTS: The 3-year-old boy was administered due to intractable diarrhea, recurrent infections, liver dysfunction and failure to thrive, though no diabetes or skin disorder was observed. Laboratory testing showed elevated liver enzymes and total IgE, decreased albumin and electrolyte imbalance. Gastrointestinal endoscopy revealed erosion and granules in the duodenum, and edema in the terminal ileum and colon. Biopsies showed villous atrophy in the duodenum and terminal ileum. Genetic testing revealed that the patient has carried a missense c.1087A>G (p.I363V) variant in the exon 10 of the FOXP3 gene. He was treated with enteral and parenteral nutrition, anti infection and Sirolimus, and was waiting for hemopoietic stem cell transplantation. CONCLUSION Although IPEX syndrome usually occur during infancy, it should not be ruled out solely based on the age, and its presentation can be variable. For male children with refractory diarrhea, autoimmune disorder and growth retardation, the diagnosis should be suspected and confirmed by genetic testing.
Child, Preschool ; Diabetes Mellitus, Type 1/genetics* ; Diarrhea/genetics* ; Forkhead Transcription Factors/genetics* ; Genetic Diseases, X-Linked/genetics* ; Genetic Testing ; Humans ; Immune System Diseases/genetics* ; Male ; Mutation ; Polyendocrinopathies, Autoimmune/genetics*

Type 1 diabetes (T1D) is an autoimmune disease that resulted from the severe destruction of the insulin-producing β cells in the pancreases of individuals with a genetic predisposition. Genome-wide studies have identified HLA and other risk genes associated with T1D susceptibility in humans. However, evidence obtained from the incomplete concordance of diabetes incidence among monozygotic twins suggests that environmental factors also play critical roles in T1D pathogenesis. Epigenetics is a rapidly growing field that serves as a bridge to link T1D risk genes and environmental exposures, thereby modulating the expression of critical genes relevant to T1D development beyond the changes of DNA sequences. Indeed, there is compelling evidence that epigenetic changes induced by environmental insults are implicated in T1D pathogenesis. Herein, we sought to summarize the recent progress in terms of epigenetic mechanisms in T1D initiation and progression, and discuss their potential as biomarkers and therapeutic targets in the T1D setting.
Diabetes Mellitus, Type 1/genetics* ; Epigenesis, Genetic/genetics* ; Genetic Predisposition to Disease/genetics* ; Humans ; Incidence ; Twins, Monozygotic

Type 1 diabetes mellitus (T1DM) is characterized by autoimmune destruction of pancreatic beta-cells in genetically predisposed individuals, eventually resulting in severe insulin deficiency. It is the most common form of diabetes in children and adolescents. Genetic susceptibility plays a crucial role in development of T1DM. The human leukocyte antigen complex plays a key role in the pathogenesis of T1DM. Furthermore, genome-wide association studies and linkage analysis have recently made a significant contribution to current knowledge relative to the impact of genetics on T1DM development and progression. This review focuses on current knowledge of genetics as a pathogenesis for T1DM. It also discusses mechanisms by which genes influence the risk of developing T1DM as well as the clinical and research applications of genetic risk scores in T1DM.
Adolescent ; Child ; Diabetes Mellitus, Type 1 ; Genetic Predisposition to Disease ; Genetics ; Genome-Wide Association Study ; Humans ; Insulin ; Leukocytes

OBJECTIVEThis study aimed to investigate the susceptibility of mice with streptozotocin(STZ)-induced diabetes mellitus (TIDM) to the uptake of pentavalent inorganic arsenic (iAsV) and the possible molecular mechanism.

METHODSTIDM was induced in mice by STZ. TIDM and normal mice were treated with 15.0 mg/kg Na2HAsO4·12H2O by intragastric administration. Then, the concentrations of arsenic in various tissues were measured by atomic fluorescence spectrometry. The gene expression levels of Pit1 and Pit2 were quantified by real-time RT-PCR, and their protein levels were detected by Western blotting in mouse heart, kidney, and liver tissues.

RESULTSThe concentrations of arsenic in STZ-induced TIDM mouse tissues were higher at 2 h after intragastric administration of Na2HAsO4·12H2O. Compared with the levels in normal mice, PIT1 and PIT2, which play a role in the uptake of iAsV, were upregulated in the livers and hearts of TIDM mice. PIT1 but not PIT2 was higher in TIDM mouse kidneys. The upregulation of Pit1 and Pit2 expression could be reversed by insulin treatment.

CONCLUSIONThe increased uptake of iAsV in TIDM mouse tissues may be associated with increased PIT1 and/or PIT2 expression.

Animals ; Arsenic ; pharmacokinetics ; Diabetes Mellitus, Experimental ; metabolism ; Environmental Pollutants ; pharmacokinetics ; Gene Expression Regulation ; physiology ; Male ; Mice ; Mice, Inbred ICR ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics ; metabolism ; Transcription Factor Pit-1 ; genetics ; metabolism

BACKGROUNDRecent studies have indicated that an imbalance of gut microbiota is associated with the development of type 1 diabetes mellitus (T1DM) and there is no literature regarding it in Chinese children yet. The aim of this study was to evaluate the alteration of gut microbiota between children with newly diagnosed T1DM and healthy controls and to determine if gut microbiota could partly explain the etiology of this disease.

METHODSA case-control study was carried out with 15 children with T1DM and 15 healthy children. The fecal bacteria composition was investigated by high-throughput sequencing of the V3-V4 region of the 16S rDNA gene and analyzed by the estimators of community richness (Chao) indexes.

RESULTSThere was a notable lower richness of fecal bacteria in T1DM group than controls (156.53 ± 36.96 vs. 130.0 ± 32.85, P = 0.047). At the genus level, the composition of Blautia was increased in T1DM group than control group whereas the composition of Haemophilus, Lachnospira, Dialister, and Acidaminococcus was decreased. In addition, we found that the percentage of Blautia was correlated positively with HbA1c (ρ = 0.40, P = 0.031), the numbers of T1DM autoantibodies (ρ = 0.42, P = 0.023), and the titers of tyrosine phosphatase autoantibodies (IA-2) (ρ = 0.82, P = 0.000) in the study.

CONCLUSIONSThis study showed that gut microbiota was associated with the development of T1DM by affecting the autoimmunity, and the results suggested a potential therapy for T1DM via modulating the gut microbiota.

Adolescent ; Autoantibodies ; immunology ; Case-Control Studies ; Child ; Computational Biology ; Diabetes Mellitus, Type 1 ; immunology ; microbiology ; Feces ; microbiology ; Female ; Gastrointestinal Microbiome ; genetics ; physiology ; Haemophilus ; genetics ; isolation & purification ; Humans ; Male ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S ; genetics

The loss of or decreased functional pancreatic β-cell is a major cause of type 1 and type 2 diabetes. Previous studies have shown that adult β-cells can maintain their ability for a low level of turnover through replication and neogenesis. Thus, a strategy to prevent and treat diabetes would be to enhance the ability of β-cells to increase the mass of functional β-cells. Consequently, much effort has been devoted to identify factors that can effectively induce β-cell expansion. This review focuses on recent reports on small molecules and protein factors that have been shown to promote β-cell expansion.
Cell Communication ; genetics ; Cell Differentiation ; genetics ; Cell Proliferation ; Diabetes Mellitus, Type 1 ; genetics ; pathology ; Diabetes Mellitus, Type 2 ; genetics ; pathology ; Humans ; Insulin-Secreting Cells ; chemistry ; metabolism ; pathology

OBJECTIVETo study the baseline distribution of polymorphisms in the promoter of peroxisome proliferators activated receptor co-activator 1 (PPARGC1A) gene in ethnic Hans from Beijing, and to assess their association with type 2 diabetes (T2DM).

METHODSA 2-stage study was designed. Firstly, the promoter region of PPAGC1A gene was screened with PCRRFLP in a small population (n=216, T2DM/control: 104/112), which was followed by a replication study of a larger group (n=1546, T2DM/control: 732/814). Fasting plasma glucose, insulin, blood lipid, height, weight, waist circumference, and blood pressure were measured in all subjects. Potential association was assessed by logistic regression. Linkage disequilibrium and haplotype analysis were conducted with Haploview software.

RESULTSFive polymorphisms were identified with Sanger sequencing, among which T-2120C (rs3755857), -1999C/G (rs2946386) and -1437T/C (rs2970870) were included for genotypic analysis based on their moderate levels of heterozygosity. No significant difference was found between the two groups. When adjusted for age and gender confounding, we have combined the OR values from population 1 and population 2 based on Mantel-Haenszel fixed model, and recognized a mild contribution of C allele of -1999C/G (rs2946386) to the 1.18-fold risk of T2DM (P=0.03, OR=118). No haplotype was associated with T2DM after permutation correction.

CONCLUSIONThe C allele of -1999C/G ( rs2946386) in the promoter region of the PPARGC1A gene is mildly associated with T2DM. Variations in the promoter region of the PPARGC1A gene seem not to confer the risk of T2DM in our population.

Adult ; Aged ; Asian Continental Ancestry Group ; ethnology ; genetics ; Blood Glucose ; metabolism ; Case-Control Studies ; China ; ethnology ; Diabetes Mellitus, Type 2 ; blood ; ethnology ; genetics ; Ethnic Groups ; genetics ; Female ; Genetic Variation ; Humans ; Lipids ; blood ; Male ; Middle Aged ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic ; Transcription Factors ; genetics