Genetic epidemiology of diabetes

Genetics and epigenetics of diabetes and its complications in India

Diabetes mellitus (DM) has become a significant health concern with an increasing rate of morbidity and mortality worldwide. India ranks second in the number of diabetes cases in the world. The increasing burden of DM can be explained by genetic predisposition of Indians to type 2 diabetes mellitus (T2DM) coupled with rapid urbanization and socio-economic development in the last 3 decades leading to drastic changes in lifestyle. Environment and lifestyle changes contribute to T2DM development by altering epigenetic processes such as DNA methylation, histone post-translational modifications, and long non-coding RNAs, all of which regulate chromatin structure and gene expression. Although the genetic predisposition of Indians to T2DM is well established, how environmental and genetic factors interact and lead to T2DM is not well understood. In this review, we discuss the prevalence of diabetes and its complications across different states in India and how various risk factors contribute to its pathogenesis. The review also highlights the role of genetic predisposition among the Indian population and epigenetic factors involved in the etiology of diabetes. Lastly, we review current treatments and emphasize the knowledge gap with respect to genetic and epigenetic factors in the Indian context. Further understanding of the genetic and epigenetic determinants will help in risk prediction and prevention as well as therapeutic interventions, which will improve the clinical management of diabetes and associated macro- and micro-vascular complications.

Benefits and risks of drug combination therapy for diabetes mellitus and its complications: a comprehensive review

Diabetes is a chronic metabolic disease, and its therapeutic goals focus on the effective management of blood glucose and various complications. Drug combination therapy has emerged as a comprehensive treatment approach for diabetes. An increasing number of studies have shown that, compared with monotherapy, combination therapy can bring significant clinical benefits while controlling blood glucose, weight, and blood pressure, as well as mitigating damage from certain complications and delaying their progression in diabetes, including both type 1 diabetes (T1D), type 2 diabetes (T2D) and related complications. This evidence provides strong support for the recommendation of combination therapy for diabetes and highlights the importance of combined treatment. In this review, we first provided a brief overview of the phenotype and pathogenesis of diabetes and discussed several conventional anti-diabetic medications currently used for the treatment of diabetes. We then reviewed several clinical trials and pre-clinical animal experiments on T1D, T2D, and their common complications to evaluate the efficacy and safety of different classes of drug combinations. In general, combination therapy plays a pivotal role in the management of diabetes. Integrating the effectiveness of multiple drugs enables more comprehensive and effective control of blood glucose without increasing the risk of hypoglycemia or other serious adverse events. However, specific treatment regimens should be tailored to individual patients and implemented under the guidance of healthcare professionals.

Differential Gene Expression in the Penile Cavernosum of Streptozotocin-Induced Diabetic Rats

PURPOSE

Men with diabetes mellitus (DM) often present with severe erectile dysfunction (ED). This ED is less responsive to current pharmacological therapies. If we know the upregulated or downregulated genes of diabetic ED, we can inhibit or enhance the expression of such genes through RNA or gene overexpression.

METHODS

To investigate gene changes associated with ED in type 1 DM, we examined the alterations of gene expression in the cavernosum of streptozotocin-induced diabetic rats. Specifically, we considered 11,636 genes (9,623 upregulated and 2,013 downregulated) to be differentially expressed in the diabetic rat cavernosum group (n=4) compared to the control group (n=4). The analysis of differentially expressed genes using the gene ontology (GO) classification indicated that the following were enriched: downregulated genes such as cell cycle, extracellular matrix, glycosylphosphatidylinositol-anchor biosynthesis and upregulated genes such as calcium signaling, neurotrophin signaling, apoptosis, arginine and proline metabolism, gap junction, transforming growth factor-β signaling, tight junction, vascular smooth muscle contraction, and vascular endothelial growth factor (VEGF) signaling. We examined a more than 2-fold upregulated or downregulated change in expression, using real time polymerase chain reaction. Analysis of differentially expressed genes, using the GO classification, indicated the enrichment.

RESULTS

Of the 41,105 genes initially considered, statistical filtering of the array analysis showed 9,623 upregulated genes and 2,013 downregulated genes with at least 2-fold changes in expression (P<0.05). With Bonferroni correction, SLC2A9 (solute carrier family 2 member 9), LRRC20 (leucine rick repeat containing 20), PLK1 (polo like kinase 1), and AATK (apoptosis-associated tyrosine kinase) were all 2-fold changed genes.

CONCLUSION

This study broadens the scope of candidate genes that may be relevant to the pathophysiology of diabetic ED. In particular, their enhancement or inhibition could represent a novel treatment for diabetic ED.

Role of Oxidative Stress in Tuberculosis Meningitis Infection in Diabetics

Tuberculosis meningitis (TBM) is a result of the invasion of the meninges with the bacilli of Mycobacterium tuberculosis (Mtb), leading to inflammation of the meninges around the brain or spinal cord. Oxidative stress occurs when the body's cells become overwhelmed with free radicals, particularly reactive oxygen species (ROS). ROS plays a significant role in the pathogenesis of TBM due to their toxic nature, resulting in impairment of the body's ability to fight off infection. ROS damages the endothelial cells and impairs the defense mechanisms of the blood-brain barrier (BBB), which contributes to CNS susceptibility to the bacteria causing TBM. Diabetes mellitus (DM) is a common condition that is characterized by the impairment of the hormone insulin, which is responsible for modulating blood glucose levels. The increased availability of glucose in individuals with diabetes results in increased cellular activity and metabolism, leading to heightened ROS production and, in turn, increased susceptibility to TBM. In this review, we summarize our current understanding of oxidative stress and its role in both TBM and DM. We further discuss how increased oxidative stress in DM can contribute to the likelihood of developing TBM and potential therapeutic approaches that may be of therapeutic value.

Differentially Expressed mRNA in Streptozotocin-Induced Diabetic Bladder Using RNA Sequencing Analysis

PURPOSE

To detect elements governing the pathogenesis of diabetic cystopathy (DC), mRNA sequencing was carried out for bladder tissues from normal rats and those with induced diabetes mellitus (DM). This research therefore offers possible underlying molecular pathways for the advancement of DC in relation to differential mRNA expression, together with visceral functional and architectural alterations noted in individuals with this condition.

METHODS

An intraperitoneal injection of streptozotocin (STZ) was utilized to provoke DM in male Sprague-Dawley rats. Dysregulation and significant variations between normal rats and those with induced DM were then identified by a fold change of ≥ 1.5 with a false discovery rate P < 0.05. Hierarchical clustering/heat map and Gene Ontology/DAVID reference sources were generated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and protein-protein interaction analysis were then performed.

RESULTS

The diabetic rodent group exhibited a greater residual urine volume (4.0 ± 0.4 mL) than their control counterparts (0.7 ± 0.2 mL, P < 0.01) at 12 weeks after diagnosis of diabetes. Expression analysis revealed 16 upregulated and 4 downregulated genes in STZDM bladder samples. A notable increase in expression was seen in PTHLH, TNFAIP6, PRC1, MAPK10, LOC686120, CASQ2, ACTG2, PDLIM3, FCHSD1, DBN1, NKD2, PDLIM7, ATF4, RBPMS2, ITGB1 and HSPB8. A notable decrease in expression was seen in SREBLF1, PBGFR1, PBLD1 and CELF1. Major genetic themes associated with mRNA upregulation and downregulation ware identified via Gene Ontology analysis and KEGG pathways. Protein to protein interaction analysis detected PDLIM3, PDLIM7, ITGB1, ACTG2 as core high frequency nodes within the network.

CONCLUSION

Changes in mRNA expression together with biological process and pathways that contribute to the etiologies underlying visceral impairment of the bladder in DM are evident. Our strategy is promising for recognizing mRNAs exclusive to the bladder in DM that might offer useful targets for diagnosis and treatment.

Association of CAPN10 gene (rs3842570) polymorphism with the type 2 diabetes mellitus among the population of Noakhali region in Bangladesh: a case-control study

Type 2 diabetes mellitus (T2DM) is a multifactorial, polygenic, and metabolically complicated disease. A large number of genes are responsible for the biogenesis of T2DM and calpain10 (CAPN10) is one of them. The association of numerous CAPN10 genetic polymorphisms in the development of T2DM has been widely studied in different populations and noticed inconclusive results. The present study is an attempt to evaluate the plausible association of CAPN10 polymorphism SNP-19 (rs3842570) with T2DM and T2DM-related anthropometric and metabolic traits in the Noakhali region of Bangladesh. This case-control study included 202 T2DM patients and 75 healthy individuals from different places in Noakhali. A significant association (p < 0.05) of SNP-19 with T2DM in co-dominant 2R/3R vs. 3R/3R (odds ratio [OR], 2.7; p=0.0014) and dominant (2R/3R) + (2R/2R) vs. 3R/3R (OR, 2.47; p=0.0011) genetic models was observed. High-risk allele 2R also showed a significant association with T2DM in the allelic model (OR, 1.67; p=0.0109). The genotypic frequency of SNP-19 variants showed consistency with Hardy-Weinberg equilibrium (p > 0.05). Additionally, SNP-19 genetic variants showed potential associations with the anthropometric and metabolic traits of T2DM patients in terms of body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol, and triglycerides. Our approach identifies the 2R/3R genotype of SNP-19 as a significant risk factor for biogenesis of T2DM in the Noakhali population. Furthermore, a large-scale study could be instrumental to correlate this finding in overall Bangladeshi population.

Association of GCK (rs1799884), GCKR (rs780094), and G6PC2 (rs560887) Gene Polymorphisms with Type 2 Diabetes among Malay Ethnics

Background  Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder, and the underlying causes remain unknown and have not been fully elucidated. Several candidate genes have been associated with T2DM in various populations with conflicting results. The variations found in glucokinase ( GCK ), glucokinase regulatory protein ( GCKR ), and glucose-6-phosphatase 2 ( G6PC2 ) genes were not well studied, particularly among Asians. Aims  The main objective of this study was to determine the candidate genetic polymorphisms of GCK (rs1799884), GCKR (rs780094), and G6PC2 (rs560887) genes in T2DM among Malay ethnics. Methods  In this candidate gene association study, a total of 180 T2DM subjects and 180 control subjects were recruited to determine the genotypes using polymerase chain reaction-restriction fragment length polymorphism and Taqman probe assay methods. Genotype and allele frequencies in case and control samples were compared using the chi-squared test to determine a significant difference. Results  The body mass index, fasting blood glucose, hemoglobin A1c, systolic and diastolic blood pressure, and total cholesterol were significantly different ( p  < 0.05) between T2DM and control subjects. The genotypic and allelic frequencies of GCK (rs1799884), GCKR (rs780094), and G6PC2 (rs560887) gene polymorphisms were significantly different between T2DM and controls ( p  < 0.05). Conclusion  Hence, rs1799884 of GCK gene and rs780094 of GCKR gene and rs560887 of the G6PC2 gene are possible genetic biomarkers in T2DM development among Malay ethnics in Malaysia.

The Effects of Race and Socioeconomics on the Relationship Between Gestational Diabetes Mellitus and Birth Outcomes: An Analysis of Southern US PRAMS data

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications. Uncontrolled GDM increases the risk of negative pregnancy outcomes for both the pregnant individual and the infant. African Americans (AAs) have higher maternal morbidity and infant mortality rates than non-Hispanic whites (NHWs). The goal of the current study was to examine racial differences in the effect of GDM on birth outcomes. The data from the Pregnancy Risk Assessment Monitoring System (PRAMS) was analyzed with a focus on four states in the southern U.S. (Alabama, Georgia, Louisiana, and Mississippi). The results presented suggest that AAs are at lower risk of GDM than NHW individuals. Even with the lower risk of GDM, AAs are at higher risk of pre-term births. In addition, socioeconomic factors and access to prenatal care play a role in birth outcomes including moderating the effect of GDM on outcomes. A discussion of potential policy interventions that may improve pregnancy outcomes is discussed including increased use of doulas to support pregnant people.

Co-transplantation of Islets-Laden Microgels and Biodegradable O2-Generating Microspheres for Diabetes Treatment

Pancreatic islets transplantation is an optimal alternative to exogenous insulin injection for long-term effective type 1 diabetes treatment. However, direct islets transplantation without any protection can induce cell necrosis due to severe host immune rejection. Insufficient O₂ supply induced by the lack of capillary network at the early stage of islets transplantation is another critical constraint limiting islets survival and insulin-secretion function. In this paper, we design a novel co-transplantation system composed of islets-laden nanocomposite microgels and O₂-generating microspheres. In particular, nanocomposite microgels confer the encapsulated islets with simultaneous physical protection and chemical anti-inflammation/immunosuppression by covalently anchoring rapamycin-loaded cyclodextrin nanoparticles to microgel network. Meanwhile, O₂-generating microspheres prepared by blending inorganic peroxides in biodegradable polycaprolactone and polylactic acid can generate in situ O₂ gas and thus avoid hypoxia environment around transplanted islets. In vivo therapeutic effect of diabetic mice proves the reversion of the high blood glucose level back to normoglycemia and superior glucose tolerance for at least 90 days post co-transplantation. In brief, the localized drug and oxygen codelivery, as well as physical protection provided by our co-transplantation system, has the potential to overcome to a large extent the inflammatory, hypoxia, and host immune rejection after islets transplantation. This new strategy may have wider application in other cell replacement therapies.

Type 2 Diabetes Mellitus: Pathogenic Features and Experimental Models in Rodents

Type 2 diabetes mellitus (T2DM) is the most common endocrine disorder (90%) in the world; it has numerous clinical, immunological, and genetic differences from type 1 diabetes mellitus. The pathogenesis of T2DM is complex and not fully clear. To date, animal models remain the main tool by which to study the pathophysiology and therapy of T2DM. Rodents are considered the best choice among animal models, because they are characterized by a small size, short induction period, easy diabetes induction, and economic efficiency. This review summarizes data on experimental models of T2DM that are currently used, evaluates their advantages and disadvantages vis-a-vis research, and describes in detail the factors that should be taken into account when using these models. Selection of a suitable model for tackling a particular issue is not always trivial; it affects study results and their interpretation.

Adenosine deaminase gene variant in diabetes and obesity

Purpose

Personal medicine is a new notion for individualizing treatment in the future. Studying pathogenic markers including genetic variants would be beneficial in better diagnosis and management of complex diseases such as diabetes and obesity. Adenosine deaminase (ADA) is a purine metabolic enzyme and modulates insulin activity in various tissues through several different mechanisms. Increased ADA activity is associated with decreased glucose uptake. A significant increase in serum deaminase activity has been reported in patients with T2DM and obesity. ADA gene polymorphisms seem to affect ADA enzymatic activity and a polymorphism at the position 4223 in the first intron of ADA gene (ADA 4223 A/C) has been previously associated with obesity. The aim of this study was to explore ADA gene 4223 A/C polymorphism and its association with obesity in patients with Type 2 diabetes.

Methods

Obese patients (N = 133: 64 diabetic +69 non-diabetic) with BMI ≥ 30 and subjects with BMI < 30 (N = 152: 83 diabetics +69 non-diabetic) were recruited into a case-control association study. Blood samples were collected and after DNA extraction, the allele and genotype frequency for ADA gene polymorphism was determined using PCR-RFLP technique.

Results

We observed a significant increase for the frequency of AA+CA genotype in non-obese patients with diabetes compared to obese patients with diabetes (P = 0.04, OR = 2.1, 95%CI; 0.93-4.9).

Conclusion

The higher frequency of AA+CA genotype in none obese diabetes individuals and lower frequency of this genotype in obese diabetes subjects indicates an important role for ADA gene polymorphism in diabetes subjects without obesity.

The effect of Chinese herbal formulas combined with metformin on modulating the gut microbiota in the amelioration of type 2 diabetes mellitus: A systematic review and meta-analysis

To assess and analyse the effectiveness and safety of combined Chinese herbal formula (CHF) and metformin treatment in the modulation of the gut microbiota in the amelioration of type 2 diabetes mellitus(T2DM), all publications addressing the effect of this combination treatment on the quantitative alterations in the gut microbiota and glucose parameters were collected. Rob tool in the Cochrane handbook was performed to evaluate the methodological quality of all included studies. Relevant information and statistics were abstracted and synthesized in Review Manager 5.4 to evaluate the efficacy of combination treatment. Sensitivity analyses and subgroup analyses were used to analyse the sources of heterogeneity. Publication bias analyses were performed by Stata software to assess the robustness and quality of the outcomes. As a result, a total of 12 eligible RCTs with 1307 T2DM participants from 7 electronic databases were included. Combined CHF with metformin treatment showed better efficacies than metformin monotherapy in regulating the structure of the gut microbiota, characterized by increased Bifidobacterium, Lactobacillus and Bacteroidetes and decreased Enterobacteriaceae, Enterococcus, and Saccharomyces along with better decreases in glycated haemoglobin, fasting plasma glucose, 2-hour postprandial blood glucose, fasting insulin and homeostasis model assessment of insulin resistance. Subgroup analyses further analysed the effect of metformin doses and CHF classifications on controlling hyperglycaemia and altering the gut microbiota. In conclusion, our meta-analysis suggested that combined CHF with metformin treatment is promising for the modulation of the gut microbiota along with ameliorating hyperglycemia in T2DM patients. Importantly, more well-designed RCTs are needed to validate the outcomes and verify the treatment value for clinical purposes.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021291524, identifier CRD42021291524.

Ischemic brain injury in diabetes and endoplasmic reticulum stress

Diabetes is a widespread disease characterized by high blood glucose levels due to abnormal insulin activity, production, or both. Chronic diabetes causes many secondary complications including cardiovascular disease: a life-threatening complication. Cerebral ischemia-related mortality, morbidity, and the extent of brain injury are high in diabetes. However, the mechanism of increase in ischemic brain injury during diabetes is not well understood. Multiple mechanisms mediate diabetic hyperglycemia and hypoglycemia-induced increase in ischemic brain injury. Endoplasmic reticulum (ER) stress mediates both brain injury as well as brain protection after ischemia-reperfusion injury. The pathways of ER stress are modulated during diabetes. Free radical generation and mitochondrial dysfunction, two of the prominent mechanisms that mediate diabetic increase in ischemic brain injury, are known to stimulate the pathways of ER stress. Increased ischemic brain injury in diabetes is accompanied by a further increase in the activation of ER stress. As there are many metabolic changes associated with diabetes, differential activation of the pathways of ER stress may mediate pronounced ischemic brain injury in subjects suffering from diabetes. We presently discuss the literature on the significance of ER stress in mediating increased ischemia-reperfusion injury in diabetes.

Gene expression atlas of energy balance brain regions

Energy balance is controlled by interconnected brain regions in the hypothalamus, brainstem, cortex, and limbic system. Gene expression signatures of these regions can help elucidate the pathophysiology underlying obesity. RNA sequencing was conducted on P56 C57BL/6NTac male mice and E14.5 C57BL/6NTac embryo punch biopsies in 16 obesity-relevant brain regions. The expression of 190 known obesity-associated genes (monogenic, rare, and low-frequency coding variants; GWAS; syndromic) was analyzed in each anatomical region. Genes associated with these genetic categories of obesity had localized expression patterns across brain regions. Known monogenic obesity causal genes were highly enriched in the arcuate nucleus of the hypothalamus and developing hypothalamus. The obesity-associated genes clustered into distinct “modules” of similar expression profile, and these were distinct from expression modules formed by similar analysis with genes known to be associated with other disease phenotypes (type 1 and type 2 diabetes, autism, breast cancer) in the same energy balance–relevant brain regions.

Type 1 diabetes: genes associated with disease development

Type 1 diabetes (T1D) is the third most common autoimmune disease which develops due to genetic and environmental risk factors. Based on the World Health Organization (WHO) report from 2014 the number of people suffering from all types of diabetes ascended to 422 million, compared to 108 million in 1980. It was calculated that this number will double by the end of 2030. In 2015 American Diabetes Association (ADA) announced that 30.3 million Americans (that is 9.4% of the overall population) had diabetes of which only approximately 1.25 million had T1D. Nowadays, T1D represents roughly 10% of adult diabetes cases total. Multiple genetic abnormalities at different loci have been found to contribute to type 1 diabetes development. The analysis of genome-wide association studies (GWAS) of T1D has identified over 50 susceptible regions (and genes within these regions). Many of these regions are defined by single nucleotide polymorphisms (SNPs) but molecular mechanisms through which they increase or lower the risk of diabetes remain unknown. Genetic factors (in existence since birth) can be detected long before the emergence of immunological or clinical markers. Therefore, a comprehensive understanding of the multiple genetic factors underlying T1D is extremely important for further clinical trials and development of personalized medicine for diabetic patients. We present an overview of current studies and information about regions in the human genome associated with T1D. Moreover, we also put forward information about epigenetic modifications, non-coding RNAs and environmental factors involved in T1D development and onset.

Identification and analysis of circulating long non-coding RNAs with high significance in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) lacks diagnostic biomarkers. Circulating long non-coding RNAs (lncRNAs) can serve as valuable diagnostic biomarkers in cardiovascular disease. To seek potential lncRNAs as a diagnostic biomarker for DCM, we investigated the genome-wide expression profiling of circulating lncRNAs and mRNAs in type 2 diabetic db/db mice with and without DCM and performed bioinformatic analyses of the deregulated lncRNA-mRNA co-expression network. Db/db mice had obesity and hyperglycemia with normal cardiac function at 6 weeks of age (diabetes without DCM) but with an impaired cardiac function at 20 weeks of age (DCM) on an isolated Langendorff apparatus. Compared with the age-matched controls, 152 circulating lncRNAs, 127 mRNAs and 3355 lncRNAs, 2580 mRNAs were deregulated in db/db mice without and with DCM, respectively. The lncRNA-mRNA co-expression network analysis showed that five deregulated lncRNAs, XLOC015617, AK035192, Gm10435, TCR-α chain, and MouselincRNA0135, have the maximum connections with differentially expressed mRNAs. Bioinformatic analysis revealed that these five lncRNAs were highly associated with the development and motion of myofilaments, regulation of inflammatory and immune responses, and apoptosis. This finding was validated by the ultrastructural examination of myocardial samples from the db/db mice with DCM using electron microscopy and changes in the expression of myocardial tumor necrosis factor-α and phosphorylated p38 mitogen-activated protein kinase in db/db mice with DCM. These results indicate that XLOC015617, AK035192, Gm10435, TCR-α chain, and MouselincRNA0135 are crucial circulating lncRNAs in the pathogenesis of DCM. These five circulating lncRNAs may have high potential as a diagnostic biomarker for DCM.

Amygdalin alleviates renal injury by suppressing inflammation, oxidative stress and fibrosis in streptozotocin-induced diabetic rats

AIMS

To explore the protective efficacies and potent mechanism of amygdalin on high glucose-cultured renal cell HBZY-1 in vitro and streptozotocin (STZ)-induced diabetic nephropathy (DN) rat in vivo.

MAIN METHODS

The cellar proliferation and generation of ROS in high-glucose cultured HBZY-1 cell were assessed by MTT and DCFH-DA assay, respectively. The fasting blood glucose levels, renal function and inflammation indexes as well as oxidative stress markers in STZ-induced diabetic rats were all measured. The histologic renal section was stained with Mason and periodic acid-Schiff (PAS) method. Immunohistochemistry and western blotting methods were applied to assess expression levels of extracellular matrix (ECM), epithelial-mesenchymal transition (EMT)-related as well as TGF-β1/Smad signaling pathway-related proteins.

KEY FINDINGS

Firstly, amygdalin significantly suppressed the excessive cell proliferation and ROS generation in HBZY-1 cells cultured with high glucose. The hyperglycemia, 24 h-UP excretion, BUN and Scr of DN rats were significantly attenuated after the chronic treatment of amygdalin. Moreover, MDA, SOD, IFN-γ and IL-12 levels in kidney tissues were all effectively reduced. Besides, amygdalin can suppress the ECM accumulation and EMT transformation by inhibiting Smad/TGF-β pathway to alleviate the renal fibrosis in renal tissues of DN model rats.

SIGNIFICANCE

Amygdalin ameliorates excessive oxidative stress, inflammation and renal tissue fibrosis of DN mainly by suppressing TGF-β1/Smad signaling pathway and regulating the key enzymes of ECM degradation.

Whole exome sequencing identifies the novel putative gene variants related with type 2 diabetes in Mizo population, northeast India

The contribution of genes towards T2D development varies among different population groups across the world. It has been reported that a number of loci involved in T2D susceptibility are common across certain population groups, but ethnicity specific variants are also observed. The population of Mizoram has an independent ethnic identity and there are no scientific records about the history of the Mizo people; which makes this ethnic group unique and interesting to study. The aim of the study focuses on the identification of the gene variants which may contribute to T2D susceptibility in Mizo-Mongloid ethnic tribe of North east India through whole exome sequencing. The variants like 328G > C (KRT18), 997G > T (CYP4A11), 2368 T > C (SLC4A3), 508G > A (SLC26A5), 1659C > T (KCNS1), 650C > A (ABCD1) 821A > T (YTHDC2), 931G > T (PINX1), 3280C > A (TNRC6A), 48C > A(TACO1), 6035A > T(LAMA1), 805C > A(ACP7) and 806A > G(ACP7) variants were not reported for any disease in the database and were found to be pathogenic in different insilico analysis softwares. The changes in protein stability upon mutation has been predicted where 35.71% increases the stability of the protein, while 64.28% of the variants decrease the stability of the protein. These findings present the population specific variants which might involve in the susceptibility to T2D in Mizo population. Further, in this study some gene variants have contribution as a possible diagnostic or prognostic marker for other diseases as well, which suggests the need for performing association analysis for different disease manifestations in Mizo population in the near future.

Family history of diabetes mellitus and long-term endocrine morbidity of the offspring

Background: Little is known regarding the long-term outcomes of offsprings to non-diabetic mothers with family history of diabetes mellitus (FHDM).Objective: The aim of the study was to determine whether being born to a non-diabetic mother with FHDM increases the risk for long-term endocrine morbidity.Methods: This is a population-based cohort study, comparing long-term endocrine morbidity between offspring born to non-diabetic mothers with and without FHDM. The Kaplan-Meier survival curve was used to compare cumulative morbidity incidence. Cox proportional hazards model was performed to control for confounders.Results: During the study period, 208,728 children met the inclusion criteria. Using a Kaplan-Meier survival curve, offspring born to non-diabetic mothers with a FHDM had higher cumulative incidence of endocrine morbidity compared to their counterparts without FHDM (Log rank test p = .014). Using a Cox model, controlling for confounders, being born to a non-diabetic mother with FHDM was an independent risk factor for long-term endocrine morbidity of the offspring (adjusted HR = 1.24, 95%CI 1.001-1.54; p = .043).Conclusion: Being born to a non-diabetic mother with a FHDM is independently associated with higher risk for long-term endocrine morbidity of the offspring.

The challenges of diagnosing diabetes in childhood

Diabetes is one of the most prevalent diseases worldwide, whereby type 1 diabetes mellitus (T1DM) alone involves nearly 15 million patients. Although T1DM and type 2 diabetes mellitus (T2DM) are the most common types, there are other forms of diabetes which may remain often under-diagnosed, or that can be misdiagnosed as being T1DM or T2DM. After an initial diagnostic step, the differential diagnosis among T1DM, T2DM, Maturity-Onset Diabetes of the Young (MODY) and others forms has important implication for both therapeutic and behavioral decisions. Although the criteria used for diagnosing diabetes mellitus are well defined by the guidelines of the American Diabetes Association (ADA), no clear indications are provided on the optimal approach to be followed for classifying diabetes, especially in children. In this circumstance, both routine and genetic blood test may play a pivotal role. Therefore, the purpose of this article is to provide, through a narrative literature review, some elements that may aid accurate diagnosis and classification of diabetes in children and young people.

TCF7L2 polymorphism a prominent marker among subjects with Type-2-Diabetes with a positive family history of diabetes

The greatest risk of developing type2 diabetes (T2DM) was conferred by rs7903146 SNP of Transcription factor7-like2 (TCF7L2) gene in many ethnic populations. The aim was to investigate the association of TCF7L2 (rs7903146) gene polymorphism among newly diagnosed diabetes subjects with different parental diabetes registry. A total of 171 subjects were categorized into 3 groups based on parental diabetes registry i.e. Conjugal Diabetes Registry (CDR) (n = 50), One Parental Diabetes Registry (OPDR) (n = 56) and Non Parental Diabetes Registry (NPDR) (n = 62) (control group). Kompetitive allele specific PCR (KASP) genotyping assay was used in real time PCR for identifying the genotypes. None of the biochemical parameters showed any significant difference between groups except age at onset of diabetes (p = 0.001). The T allele of TCF7L2 (rs7903146) was associated with significant risk of diabetes. TT genotype which doubles the diabetes risk showed significant association among OPDR whereas in CDR both CT and TT genotypes showed significant association than CC wild type. The 'T' allele of TCF7L2 SNP was associated with significant risk when compared between OPDRvsNPDR (OR 2.45, p = 0.003) and CDRvsNPDR (OR 2.82, p = 0.0007). In conclusion, TCF7L2 gene polymorphism and positive family history of diabetes are strongly associated irrespective of the presence of other risk factors among diabetes subjects.

Is there an association between family history of diabetes mellitus and long-term cardiovascular hospitalizations of offspring?

OBJECTIVE

Gestational diabetes mellitus (GDM) was previously found to be an independent risk factor for long-term cardiovascular morbidity of parturients and their offspring. The objective of this study was to investigate the association between family history of diabetes mellitus (DM) in non-diabetic mothers and long-term pediatric cardiovascular hospitalizations of their offspring.

STUDY DESIGN

In a hospital-based cohort study, the incidence of cardiovascular disorders was compared between offspring of non-diabetic mothers with and without a family history of DM. Cardiovascular hospitalizations were assessed up until 18years of age according to a predefined set of ICD-9 codes associated with hospitalization of offspring. Exclusion criteria included multiple gestations, mothers with pre-gestational or gestational diabetes, lack of prenatal care, and children with congenital malformations and chromosomal abnormalities. A Kaplan-Meier survival curve was used to compare cumulative hospitalizations incidence. A cox proportional hazards model was performed to control for confounders.

RESULTS

A total of 208,728 deliveries were included in the study. Of them, 17,040 (8.2%) offspring were born to non-diabetic mothers with a family history of DM. Significant differences in the rates of IVF, induction of labor, obesity, hypertensive disorders of pregnancy, smoking and birth weight were found between the two study groups. Total cardiovascular hospitalizations were comparable between the study groups (0.6% vs. 0.7%, p=0.416). The Kaplan-Meier survival curve exhibited no difference in the cumulative incidence of total cardiovascular hospitalizations of the offspring (log-rank test, p=0.271). A Cox regression model found that a family history of DM in non-diabetic mothers was not independently associated with long-term cardiovascular hospitalizations of the offspring after controlling for the following confounders: maternal age, birth weight, caesarian section and maternal hypertensive disorders (aHR=1.130, 95% CI 0.930-1.374, p=0.220).

CONCLUSION

A family history of DM in non-diabetic parturients, does not increase the risk for cardiovascular hospitalizations of their offspring.

Gut microbiota imbalances in Tunisian participants with type 1 and type 2 diabetes mellitus

Gut microbiota plays an important role in the regulation of the immune system and host's metabolism. We aimed to characterize the gut microbiota of Tunisian participants with and without diabetes.We enrolled ten participants with type 1 diabetes mellitus (T1DM), ten patients with type 2 diabetes mellitus (T2DM), and 11 subjects without diabetes. Bacteria was quantified in fecal samples by quantitative PCR (qPCR). Statistical tests and multivariate analysis were performed using RStudio program.Results showed that the proportions of Firmicutes, Akkermansia muciniphila, and Faecalibacterium prausnitzii (P≤0.041), as well as, the ratio Firmicutes/Bacteroidetes decreased in participants with T1DM compared with those without diabetes (p = 0.036). Participants with T2DM presented a reduction in the amounts of A. muciniphila and F. prausnitzii compared with those without diabetes (P≤0.036). Furthermore, A. muciniphila is negatively correlated with glucose level (P=0.022) and glycated hemoglobin (HbA1c) (P=0.035). Multivariate analysis revealed that participants with diabetes formed a cluster apart compared with those without diabetes.In conclusion the gut bacteria of Tunisian participants with diabetes was altered. The gut bacterial profile, especially the distribution of A muciniphila in participants with diabetes was affected by glycemic dysregulation. The investigation of the gut microbiota may help clinicians to improve diagnosis and treatment of diabetes and its complications.

Identifying Pathogenic Variants of Monogenic Diabetes Using Targeted Panel Sequencing in an East Asian Population

PURPOSE

Monogenic diabetes is a specific type of diabetes in which precision medicine could be applied. In this study, we used targeted panel sequencing to investigate pathogenic variants in Korean patients clinically suspected to have monogenic diabetes.

METHODS

The eligibility criteria for inclusion were non-type 1 diabetes patients with an age of onset ≤ 30 years and a BMI (body mass index) ≤ 30 kg/m2. Among the 2,090 non-type 1 diabetes patients, 109 were suspected to have monogenic diabetes and subjected to genetic testing. We analyzed 30 monogenic diabetes genes using targeted panel sequencing. The pathogenicity of the genetic variants was evaluated according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines.

RESULTS

Among the 109 suspected monogenic diabetes patients, 23 (21.1%) patients harbored pathogenic/likely pathogenic variants. A total of 14 pathogenic/likely pathogenic variants of common maturity onset diabetes of the young (MODY) genes were identified in GCK, HNF1A, HNF4A, and HNF1B. Other pathogenic/likely pathogenic variants were identified in WFS1, INS, ABCC8 and FOXP3. The mitochondrial DNA 3243 A>G variant was identified in five participants. Patients with pathogenic/likely pathogenic variants had a significantly higher MODY probability, a lower BMI, and a lower C-peptide level than those without pathogenic/likely pathogenic variants (P=0.007, P=0.001, and P=0.012, respectively).

CONCLUSIONS

Using targeted panel sequencing followed by pathogenicity evaluation, we were able to make molecular genetic diagnoses for 23 (21.1%) suspected monogenic diabetes patients. Lower BMI, higher MODY probability, and lower C-peptide levels were characteristics of these participants.

Advances in immunotherapy of type I diabetes

Type 1 diabetes mellitus (T1DM) is an autoimmune disease affecting 3 million individuals in the U.S. The pathogenesis of T1DM is driven by immune-mediated destruction of pancreatic β cells, the source of glucose regulator insulin. While T1DM can be successfully managed with insulin replacement therapy, approaches that can modify the underlying immuno-pathology of β cell destruction has been long sought after. Immunotherapy can attenuate T cell responses against β cell antigens. Given the detailed cellular and molecular definitions of T1DM immune responses, rational immunomodulation can be and have been developed in mouse models, and in some instances, tested in humans. The possibility of identifying individuals who are predisposed to T1DM through genotyping lend to the possibility of preventive vaccines. While much has been accomplished in delineating the mechanisms of immunotherapies, some of which are being tested in humans, long-term preservation of β cells and insulin independency has not been achieved. In this regard, the drug delivery field has much to offer in maximizing the benefits of immune modulators by optimizing spatiotemporal presentation of antigens and costimulatory signals. In this review, we attempt to capture the current state of T1DM immunotherapy by highlighting representative studies.

Two Novel Candidate Genes for Insulin Secretion Identified by Comparative Genomics of Multiple Backcross Mouse Populations

To identify novel disease genes for type 2 diabetes (T2D) we generated two backcross populations of obese and diabetes-susceptible New Zealand Obese (NZO/HI) mice with the two lean mouse strains 129P2/OlaHsd and C3HeB/FeJ. Subsequent whole-genome linkage scans revealed 30 novel quantitative trait loci (QTL) for T2D-associated traits. The strongest association with blood glucose [12 cM, logarithm of the odds (LOD) 13.3] and plasma insulin (17 cM, LOD 4.8) was detected on proximal chromosome 7 (designated Nbg7p, NZO blood glucose on proximal chromosome 7) exclusively in the NZOxC3H crossbreeding, suggesting that the causal gene is contributed by the C3H genome. Introgression of the critical C3H fragment into the genetic NZO background by generating recombinant congenic strains and metabolic phenotyping validated the phenotype. For the detection of candidate genes in the critical region (30-46 Mb), we used a combined approach of haplotype and gene expression analysis to search for C3H-specific gene variants in the pancreatic islets, which appeared to be the most likely target tissue for the QTL. Two genes, Atp4a and Pop4, fulfilled the criteria from our candidate gene approaches. The knockdown of both genes in MIN6 cells led to decreased glucose-stimulated insulin secretion, indicating a regulatory role of both genes in insulin secretion, thereby possibly contributing to the phenotype linked to Nbg7p In conclusion, our combined- and comparative-cross analysis approach has successfully led to the identification of two novel diabetes susceptibility candidate genes, and thus has been proven to be a valuable tool for the discovery of novel disease genes.

The rs1256031 of estrogen receptor β gene is associated with type 2 diabetes

AIM

To determine the association between the rs1256031 polymorphism and risk of developing type 2 diabetes.

MATERIALS AND METHODS

Cases and controls study. 597 individuals with type 2 diabetes and 605 without it participated. Genotyping of the rs1256031 polymorphism of the ERβ gene was performed by real-time PCR using TaqMan assay. For the multivariate analysis, a multiple logistic regression was performed that included the main confounding variables.

RESULTS AND CONCLUSION

A multiple logistic regression analysis was performed, adjusting for age, WHR, BMI and gender. The dominant model showed a protective effect compared to the TT genotype (OR = 0.596, IC95% [0.458-0.776]).

DISCUSSION

The proportions of native American, European and African ancestry were characterized and no difference was found in the study groups. The protective effect obtained in the dominant model could to be due a regulatory function in the transcription or the processing of the primary transcript. Our result are the first to report an association between the polymorphism rs1256031 and the reduction of the risk of T2D in the Mexican population. The rs1256031 polymorphism show reduced risk of developing T2D and is potential markers for predicting T2D.

Hydroxytyrosol ameliorates insulin resistance by modulating endoplasmic reticulum stress and prevents hepatic steatosis in diet-induced obesity mice

Endoplasmic reticulum (ER) is a principal organelle responsible for energy and nutrient management. Its dysfunction has been viewed in the context of obesity and related glucolipid metabolic disorders. However, therapeutic approaches to improve ER adaptation and systemic energy balance in obesity are limited. Thus, we examined whether hydroxytyrosol (HT), an important polyphenolic compound found in virgin olive oil, could correct the metabolic impairments in diet-induced obesity (DIO) mice. Here, we found that HT gavage for 10 weeks significantly ameliorated glucose homeostasis and chronic inflammation and decreased hepatic steatosis in DIO mice. At the molecular level, ER stress indicators, inflammatory and insulin signaling markers demonstrated that high-fat diet (HFD)-induced ER stress and insulin resistance (IR) in insulin sensitive tissue were corrected by HT. In vitro studies confirmed that HT supplementation (100 μM) attenuated palmitate-evoked ER stress, thus rescuing the downstream JNK/IRS pathway. As a result from suppression of ER stress in the liver, HT further decreased hepatic sterol regulatory element-binding protein-1 expression (SREBP1). Additionally, aberrant expression of genes involved in hepatic lipogenesis (SREBP1, ACC, FAS, SCD1) caused by HFD was restored by HT. These findings suggested that HT ameliorated chronic inflammation and IR and decreased hepatic steatosis in obesity by beneficial modulation of ER stress.

Gene Expression Meta-Analysis of Seven Candidate Gene Sets for Diabetes Traits Following a GWAS Pathway Study

Seven gene sets were significantly enriched for SNP associations with diabetes, and considered as potential diabetes pathways in a previous meta-analysis of diabetes GWAS. This study aims to examine if these gene sets also have expression associations with diabetes. The analysis was conducted using pooled data from 23 diabetes gene expression studies. Gene associations were examined using linear modeling with an empirical Bayes approach, and pathway associations were investigated by testing enrichment for significant genes. Meta-analyses were performed to investigate gene and pathway associations in all studies and tissue types. The analysis showed that six gene sets and three member genes of ACADSB, RASSF2, and KLF12 had significant associations with diabetes traits. The findings suggest that these gene sets are related to diabetes regulation, and their functions tend to be tissue non-specific.

The FTO variant is associated with chronic complications of diabetes mellitus in Czech population

BACKGROUND

Genome-wide association studies have resulted in the identification of the FTO gene as an important genetic determinant of diabetes mellitus. The aim of this study was to confirm the role of this gene in the development of DM in the Czech-Slavonic population and to analyse whether this gene is associated with common DM complications.

METHODS

Two groups of patients (814 with T1DM and 848 with T2DM) and a group of healthy controls (2339 individuals) - both of Czech origin - were genotyped for the FTO rs17817449 SNP. ANOVA and logistic regression were used for the statistical evaluations.

RESULTS

The frequency of the GG genotype was significantly higher in T2DM (25.4% vs. 16.7%, P<0.0005) but not in T1DM patients (19.3% vs. 16.7%, P=0.20) than in controls. The increased risk of development of diabetic nephropathy was observed both for T1DM patients (GG vs. TT homozygotes, P<0.01) and T2DM patients (G carriers vs. TT homozygotes, P<0.05). FTO genotype predicted the development of diabetic neuropathy (GG vs. TT comparison; P<0.01) in the T2DM patients only. No association between FTO genotype and development of retinopathy was detected. All presented values are after adjustment for age, sex, BMI and duration of diabetes.

CONCLUSIONS

We confirm the association between the FTO rs17817449 SNP and susceptibility to T2DM in the Czech-Slavonic population. The same variant is associated with a spectrum of chronic complications in both types of diabetes.

DNA methylation links genetics, fetal environment, and an unhealthy lifestyle to the development of type 2 diabetes

Type 2 diabetes is a complex trait with both environmental and hereditary factors contributing to the overall pathogenesis. One link between genes, environment, and disease is epigenetics influencing gene transcription and, consequently, organ function. Genome-wide studies have shown altered DNA methylation in tissues important for glucose homeostasis including pancreas, liver, skeletal muscle, and adipose tissue from subjects with type 2 diabetes compared with nondiabetic controls. Factors predisposing for type 2 diabetes including an adverse intrauterine environment, increasing age, overweight, physical inactivity, a family history of the disease, and an unhealthy diet have all shown to affect the DNA methylation pattern in target tissues for insulin resistance in humans. Epigenetics including DNA methylation may therefore improve our understanding of the type 2 diabetes pathogenesis, contribute to development of novel treatments, and be a useful tool to identify individuals at risk for developing the disease.

DNA methylation alters transcriptional rates of differentially expressed genes and contributes to pathophysiology in mice fed a high fat diet

OBJECTIVE

Overnutrition can alter gene expression patterns through epigenetic mechanisms that may persist through generations. However, it is less clear if overnutrition, for example a high fat diet, modifies epigenetic control of gene expression in adults, or by what molecular mechanisms, or if such mechanisms contribute to the pathology of the metabolic syndrome. Here we test the hypothesis that a high fat diet alters hepatic DNA methylation, transcription and gene expression patterns, and explore the contribution of such changes to the pathophysiology of obesity.

METHODS

RNA-seq and targeted high-throughput bisulfite DNA sequencing were used to undertake a systematic analysis of the hepatic response to a high fat diet. RT-PCR, chromatin immunoprecipitation and in vivo knockdown of an identified driver gene, Phlda1, were used to validate the results.

RESULTS

A high fat diet resulted in the hypermethylation and decreased transcription and expression of Phlda1 and several other genes. A subnetwork of genes associated with Phlda1 was identified from an existing Bayesian gene network that contained numerous hepatic regulatory genes involved in lipid and body weight homeostasis. Hepatic-specific depletion of Phlda1 in mice decreased expression of the genes in the subnetwork, and led to increased oil droplet size in standard chow-fed mice, an early indicator of steatosis, validating the contribution of this gene to the phenotype.

CONCLUSIONS

We conclude that a high fat diet alters the epigenetics and transcriptional activity of key hepatic genes controlling lipid homeostasis, contributing to the pathophysiology of obesity.

4-PBA reverses autophagic dysfunction and improves insulin sensitivity in adipose tissue of obese mice via Akt/mTOR signaling

BACKGROUND

4-phenyl butyric acid (4-PBA) has been considered as a key regulator of insulin resistance in obesity. However the mechanism of 4-PBA involved in insulin resistance remains elusive.

METHODS

We evaluated the effect of 4-PBA on abnormal autophagy and endoplasmic reticulum (ER) stress in obese mice. 4-PBA was administered in obese mice and adipocyte models, and metabolic parameters, autophagy markers, ER stress indicators, Akt/mTOR signaling and insulin signaling molecular were assessed.

RESULTS

4-PBA treatment not only reversed autophagic dysfunction and ER stress, but also improved impaired insulin signaling in tunicamycin-induced adipocytes, and 4-PBA also inhibited activated ER stress and elevated insulin sensitivity in adipocytes with Atg7 siRNA. Additionally, administration of 4-PBA improves glucose tolerance and insulin sensitivity in obese mice via regulating abnormal autophagy and ER stress in adipose tissue. The protective effects of 4-PBA were nullified by suppression of Akt and mTOR in adipocytes, suggesting that 4-PBA inhibits autophagy and restores insulin sensitivity via Akt/mTOR signaling partially.

CONCLUSIONS

4-PBA reverses autophagic dysfunction and improves insulin sensitivity in adipose tissue of obese mice via Akt/mTOR signaling partly, which could be regarded as novel opportunities for treatment of insulin resistance.

Genome-scale transcriptional analysis reveals key genes associated with the development of type II diabetes in mice

Diabetes mellitus is one of the primary diseases that pose a threat to human health. The focus of the present study is type II diabetes (T2D), which is caused by obesity and is the most prevalent type of diabetes. However, genome-scale transcriptional analysis of diabetic liver in the development process of T2D is yet to be further elucidated. Microassays were performed on liver tissue samples from three-, six- and nine-week-old db/db mice with diabetes and db/m mice to investigate differentially expressed mRNA. Based on the results of genome-scale transcriptional analysis, five genes were screened in the present study: chromobox 8 (CBX8), de-etiolated homolog 1 and damage specific DNA binding protein 1 associated 1 (DDA1), Phosphoinositide-3-kinase regulatory subunit 6 (PIK3R6), WD repeat domain 41 (WDR41) and Glycine Amidinotransferase (GATM). At three weeks of age, no significant differences in levels or ratios of expression were observed. However, at six and nine weeks, expression of CBX8, DDA1, PIK3R6 and WDR41 was significantly upregulated (P<0.05) in the db/db model group compared with the control group, whereas GATM expression was significantly downregulated (P<0.05). These results suggest that T2D-related differential expression of genes becomes more marked with age, which was confirmed via reverse transcription-quantitative polymerase chain reaction. Genome-scale transcriptional analysis in diabetic mice provided a novel insight into the molecular. events associated with the role of mRNAs in T2D development, with specific emphasis upon CBX8, DDA1, PIK3R6, GATM and WDR41. The results of the present study may provide rationale for the investigation of the target genes of these mRNAs in future studies.

Novel variants of mitochondrial DNA associated with Type 2 diabetes mellitus in Moroccan population

In this study, we investigated the association of mtDNA variants and haplogroups with Type 2 diabetes (T2D) in Moroccan patients. The Hypervariable Segments 1 of the mtDNA was sequenced in 108 diabetic patients and 97 controls. Association analyses were performed using Fisher's exact test and multivariate logistic regression. The prevalence of five mtDNA variants (C16187T, C16270T, T16172C, A16293G, and C16320T) was significantly higher in cases than in controls. Among these variants, only C16270T (p = .02) and C16320T (p = .03) remains significant after adjusting by age and gender. We showed that C16270T and C16320T variants were strongly associated with increased risk of T2D in Moroccan patients.

Anti-diabetic effect of 3-hydroxy-2-naphthoic acid, an endoplasmic reticulum stress-reducing chemical chaperone

Lots of experimental and clinical evidences indicate that chronic exposure to saturated fatty acids and high level of glucose is implicated in insulin resistance, beta cell failure and ultimately type 2 diabetes. In this study, we set up cell-based experimental conditions to induce endoplasmic reticulum (ER) stress and insulin resistance using high concentration of palmitate (PA). Hydroxynaphthoic acids (HNAs) were formerly identified as novel chemical chaperones to resolve ER stress induced by tunicamycin. In this study, we found the compounds have the same suppressive effect on PA-induced ER stress in HepG2 cells. The representing compound, 3-HNA reduced PA-induced phosphorylation of JNK, IKKβ and IRS1 (S307) and restored insulin signaling cascade which involves insulin receptor β, IRS1 and Akt. The insulin sensitizing effect of 3-HNA was confirmed in 3T3-L1 adipocytes, where the compound augmented insulin signaling and glucose transporter 4 (GLUT4) membrane translocation. 3-HNA also protected the pancreatic beta cells from PA-induced apoptosis by reducing ER stress. Upon 3-HNA treatment to ob/ob mice at 150mg/kg/day dosage, the diabetic parameters including glucose tolerance and systemic insulin sensitivity were significantly improved. Postmortem examination showed that 3-HNA markedly reduced ER stress and insulin resistance in the liver tissues and it sensitized insulin signaling in the liver and the skeletal muscle. Our results demonstrated that 3-HNA can sensitize insulin signaling by coping with lipotoxicity-induced ER stress as a chemical chaperone and suggested it holds therapeutic potential for insulin resistance and type 2 diabetes.

High-fat-diet induced development of increased fasting glucose levels and impaired response to intraperitoneal glucose challenge in the collaborative cross mouse genetic reference population

Background

The prevalence of Type 2 Diabetes (T2D) mellitus in the past decades, has reached epidemic proportions. Several lines of evidence support the role of genetic variation in the pathogenesis of T2D and insulin resistance. Elucidating these factors could contribute to developing new medical treatments and tools to identify those most at risk. The aim of this study was to characterize the phenotypic response of the Collaborative Cross (CC) mouse genetic resource population to high-fat diet (HFD) induced T2D-like disease to evluate its suitability for this purpose.

Results

We studied 683 mice of 21 different lines of the CC population. Of these, 265 mice (149 males and 116 females) were challenged by HFD (42 % fat); and 384 mice (239 males and145 females) of 17 of the 21 lines were reared as control group on standard Chow diet (18 % fat). Briefly, 8 week old mice were maintained on HFD until 20 weeks of age, and subsequently assessed by intraperitoneal glucose tolerance test (IPGTT). Biweekly body weight (BW), body length (BL), waist circumstance (WC), and body mass index (BMI) were measured. On statistical analysis, trait measurements taken at 20 weeks of age showed significant sex by diet interaction across the different lines and traits. Consequently, males and females were analyzed, separately. Differences among lines were analyzed by ANOVA and shown to be significant (P <0.05), for BW, WC, BMI, fasting blood glucose, and IPGTT-AUC. We use these data to infer broad sense heritability adjusted for number of mice tested in each line; coefficient of genetic variation; genetic correlations between the same trait in the two sexes, and phenotypic correlations between different traits in the same sex.

Conclusions

These results are consistent with the hypothesis that host susceptibility to HFD-induced T2D is a complex trait and controlled by multiple genetic factors and sex, and that the CC population can be a powerful tool for genetic dissection of this trait.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0321-x) contains supplementary material, which is available to authorized users.

Paternal long-term exercise programs offspring for low energy expenditure and increased risk for obesity in mice

Obesity has more than doubled in children and tripled in adolescents in the past 30 yr. The association between metabolic disorders in offspring of obese mothers with diabetes has long been known; however, a growing body of research indicates that fathers play a significant role through presently unknown mechanisms. Recent observations have shown that changes in paternal diet may result in transgenerational inheritance of the insulin-resistant phenotype. Although diet-induced epigenetic reprogramming via paternal lineage has recently received much attention in the literature, the effect of paternal physical activity on offspring metabolism has not been adequately addressed. In the current study, we investigated the effects of long-term voluntary wheel-running in C57BL/6J male mice on their offspring's predisposition to insulin resistance. Our observations revealed that fathers subjected to wheel-running for 12 wk produced offspring that were more susceptible to the adverse effects of a high-fat diet, manifested in increased body weight and adiposity, impaired glucose tolerance, and elevated insulin levels. Long-term paternal exercise also altered expression of several metabolic genes, including Ogt, Oga, Pdk4, H19, Glut4, and Ptpn1, in offspring skeletal muscle. Finally, prolonged exercise affected gene methylation patterns and micro-RNA content in the sperm of fathers, providing a potential mechanism for the transgenerational inheritance. These findings suggest that paternal exercise produces offspring with a thrifty phenotype, potentially via miRNA-induced modification of sperm.

Genetic polymorphism of APOB is associated with diabetes mellitus in sickle cell disease

Environmental variations have strong influences in the etiology of type 2 diabetes mellitus. In this study, we investigated the genetic basis of diabetes in patients with sickle cell disease (SCD), a Mendelian disorder accompanied by distinct physiological conditions of hypoxia and hyperactive erythropoiesis. Compared to the general African American population, the prevalence of diabetes as assessed in two SCD cohorts of 856 adults was low, but it markedly increased with older age and overweight. Meta-analyses of over 5 million single-nucleotide polymorphisms (SNPs) in the two SCD cohorts identified a SNP, rs59014890, the C allele of which associated with diabetes risk at P = 3.2 × 10(-8) and, surprisingly, associated with decreased APOB expression in peripheral blood mononuclear cells (PBMCs). The risk allele of the APOB polymorphism was associated with overweight in 181 SCD adolescents, with diabetes risk in 592 overweight, non-SCD African Americans ≥ 45 years of age, and with elevated plasma lipid concentrations in general populations. In addition, lower expression level of APOB in PBMCs was associated with higher values for percent hemoglobin A1C and serum total cholesterol and triglyceride concentrations in patients with Chuvash polycythemia, a congenital disease with elevated hypoxic responses and increased erythropoiesis at normoxia. Our study reveals a novel, environment-specific genetic polymorphism that may affect key metabolic pathways contributing to diabetes in SCD.

Examination of the brain natriuretic peptide rs198389 single-nucleotide polymorphism on type 2 diabetes mellitus and related phenotypes in an Algerian population

BACKGROUND

In European populations, the NPPB rs198389 single nucleotide polymorphism (SNP) is associated with a reduced risk of type 2 diabetes mellitus (T2DM). We investigated the putative associations between NPPB rs198389, the T2DM risk and quantitative metabolic traits in an Algerian population.

METHODS

The association analysis was performed as a T2DM case-control study (with 78 cases and 645 controls) nested into the ISOR population-based study.

RESULTS

The NPPB rs198389 SNP was not associated with T2DM (odds ratio (OR) [95% confidence interval (CI)]=0.73 [0.51-1.04], p=0.08). However, the C allele was associated with lower fasting plasma insulin levels (p=0.05) and a lower homeostatic model assessment insulin resistance index (p=0.05) in non-diabetic individuals.

CONCLUSION

The NPPB rs198389 SNP might modulate fasting insulin levels in an Algerian population.

The uniform-score gene set analysis for identifying common pathways associated with different diabetes traits

Background

Genetic heritability and expression study have shown that different diabetes traits have common genetic components and pathways. A computationally efficient pathway analysis of GWAS results will benefit post-GWAS study of SNP associations and identification of common genetic pathways from diabetes GWAS can help to improve understanding of the disease pathogenesis.

Results

We proposed a uniform-score gene-set analysis (USGSA) with implemented package to unify different gene measures by a uniform score for identifying pathways from GWAS data, and use a pre-generated permutation distribution table to quickly obtain multiple-testing adjusted p-value. Simulation studies of uniform score for four gene measures (minP, 2ndP, simP and fishP) have shown that USGSA has strictly controlled family-wise error rate. The power depends on types of gene measure. USGSA with a two-stage study strategy was applied to identify common pathways associated with diabetes traits based on public dbGaP GWAS results. The study identified 7 gene sets that contain binding motifs at promoter region of component genes for 5 transcription factors (TFs) of FOXO4, TCF3, NFAT, VSX1 and POU2F1, and 1 microRNA of mir-218. These gene sets include 25 common genes that are among top 5% of the gene associations over genome for all GWAS. Previous evidences showed that nearly all of these genes are mainly expressed in the brain.

Conclusions

USGSA is a computationally efficient approach for pathway analysis of GWAS data with promoted interpretability and comparability. The pathway analysis suggested that different diabetes traits share common pathways and component genes are potentially regulated by common TFs and microRNA. The result also indicated that the central nervous system has a critical role in diabetes pathogenesis. The findings will be important in formulating novel hypotheses for guiding follow-up studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1515-3) contains supplementary material, which is available to authorized users.

Selecting a prospective test for early detection of diabetic polyneuropathy

Microneurolysis of entrapped peripheral nerve has the best chance of success when compression has not created significant axonal loss. The purpose of this study is to learn the best way to identify potential surgical candidates at the earliest time for intervention, by examining patients in a clinical setting using objective, electrodiagnostic nerve conduction studies (NCS), and subjective touch threshold studies, Semmes-Weinstein monofilaments (SWM) and Pressure-Specified Sensory Device™ (PSSD). Fifty-five patients with diabetic polyneuropathy over the age of 30 years were included. Neuropathy symptom score was the gold standard for statistical calculation, with a prevalence of 70%. In the symptomatic population, prevalence was 64% for NCS (n = 25), 59% for SWM (n = 43), and 88% for PSSD (n = 51). In the asymptomatic population, prevalence was 70% for NCS, 27% for SWM, and 92% for PSSD. It is concluded that the PSSD is the most sensitive device of those tested for identifying peripheral neuropathy in an at risk population of patients.

Toll-like receptor 4 gene Asp299Gly and Thr399Ile polymorphisms in type 2 diabetes mellitus: a meta-analysis of 15,059 subjects

AIMS

Toll-like receptor 4 (TLR4) gene Asp299Gly and Thr399Ile polymorphisms have been reported to be associated with susceptibility to type 2 diabetes mellitus (T2DM) with inconsistent results. In an effort to clarify earlier inconclusive results, a meta-analysis evaluating the precise associations between TLR4 gene Asp299Gly and Thr399Ile polymorphisms and T2DM risk was performed.

METHODS

We searched the PubMed, Embase, Web of Science, CBMdisc, CNKI, and Google Scholar until July 17, 2014. Additionally, hand searching of the references of identified articles were performed. Original observational studies dealing with the associations between TLR4 gene Asp299Gly and Thr399Ile polymorphisms and T2DM risk were selected. Heterogeneity and publication bias were determined and the meta-analysis was performed by Review Manager 5.1.4 and Stata 11.0.

RESULTS

Seventeen articles involving 25 studies were included in the final meta-analysis, covering a total of 5963 T2DM cases and 9096 controls. For TLR4 gene Asp299Gly polymorphism, 17 studies were combined showing no evidence for association between TLR4 gene Asp299Gly polymorphism and T2DM risk. For TLR4 gene Thr399Ile polymorphism, eight studies were combined. There was also lack of evidence for significant association between TLR4 gene Thr399Ile polymorphism and T2DM risk. In addition, the similar results were obtained in the sensitivity analyses.

CONCLUSIONS

The present meta-analysis indicates that TLR4 gene Asp299Gly and Thr399Ile polymorphisms are not associated with increased T2DM risk.

Effect of resveratrol on behavioral performance of streptozotocin-induced diabetic mice in anxiety tests

The aim of this study was to evaluate with anxiety tests the effect of resveratrol (RSV) on streptozotocin (STZ)-induced diabetic mouse behavioral performance at the second and fourth week of treatment. Confirmed diabetic mice (>250 mg/dl of glucose in blood after STZ injection) were treated with RSV (RDM, n=12) or control treated (DM, n=12) for 4 weeks. DM and RDM were tested in the Open Field Test (OFT) and Elevated Plus Maze (EPM). In the second week of RSV treatment, a higher grooming frequency (P<0.05) and a lower defecation and rearing frequency (P<0.05) were detected in the OFT in the RDM group compared with the DM. There was a higher grooming frequency (P<0.05) and higher percentage of entries in open arms (P<0.05) in the RDM group than in the DM group in the EPM. However, in the fourth week of RSV treatment, the only effect observed was a higher grooming frequency in the RDM group than in the DM group (P<0.05) in the EPM. In conclusion, RSV treatment in diabetic mice provoked anxiolytic-like effects in both tests (OFT and EPM), and these effects were observed in a short time window (2 weeks). It is suggested that RSV may help diabetic animals to adapt to new stressing and anxiety situations and thus to improve their welfare.