The genetic and regulatory architecture of ERBB3-type 1 diabetes susceptibility locus

Liver-derived Neuregulin1α stimulates compensatory pancreatic β cell hyperplasia in insulin resistance

Compensatory pancreatic islet hyperplasia is an adaptive response to increased systemic insulin demand, although factors meditating this response remain poorly understood. Here, we show that a liver-derived secreted protein, Neuregulin1α, promotes compensatory proliferation of pancreatic β cells in type 2 diabetes. Liver Neuregulin1α expression and serum Neuregulin1α levels increase in male mice fed an obesity-inducing diet. Male mice lacking either Neuregulin1 in liver or its receptor, ErbB3, in β cells deteriorate systemic glucose disposal due to impaired β cell expansion with reduced insulin secretion when fed the obesity-inducing diet. Mechanistically, Neuregulin1α activates ERBB2/3-ERK signaling to stimulate β cell proliferation without altering glucose-stimulated insulin secretion potential. In patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and obesity but without type 2 diabetes serum Neuregulin1α levels increase, while in patient with MASLD and type 2 diabetes show markedly reduced levels of Neuregulin1α. These results suggest that Neuregulin1α serves as a hepatokine that can expand functional β cell mass in type 2 diabetes.

Based on systematic druggable genome-wide Mendelian randomization identifies therapeutic targets for diabetes

Purpose

Diabetes and its complications cause a heavy burden of disease worldwide. In recent years, Mendelian randomization (MR) has been widely used to discover the pathogenesis and epidemiology of diseases, as well as to discover new therapeutic targets. Therefore, based on systematic "druggable" genomics, we aim to identify new therapeutic targets for diabetes and analyze its pathophysiological mechanisms to promote its new therapeutic strategies.

Material and method

We used double sample MR to integrate the identified druggable genomics to evaluate the causal effect of quantitative trait loci (eQTLs) expressed by druggable genes in blood on type 1 and 2 diabetes (T1DM and T2DM). Repeat the study using different data sources on diabetes and its complications to verify the identified genes. Not only that, we also use Bayesian co-localization analysis to evaluate the posterior probabilities of different causal variations, shared causal variations, and co-localization probabilities to examine the possibility of genetic confounding. Finally, using diabetes markers with available genome-wide association studies data, we evaluated the causal relationship between established diabetes markers to explore possible mechanisms.

Result

Overall, a total of 4,477 unique druggable genes have been gathered. After filtering using methods such as Bonferroni significance (P<1.90e-05), the MR Steiger directionality test, Bayesian co-localization analysis, and validation with different datasets, Finally, 7 potential druggable genes that may affect the results of T1DM and 7 potential druggable genes that may affect the results of T2DM were identified. Reverse MR suggests that C4B may play a bidirectional role in the pathogenesis of T1DM, and none of the other 13 target genes have a reverse causal relationship. And the 7 target genes in T2DM may each affect the biomarkers of T2DM to mediate the pathogenesis of T2DM.

Conclusion

This study provides genetic evidence supporting the potential therapeutic benefits of targeting seven druggable genes, namely MAP3K13, KCNJ11, REG4, KIF11, CCNE2, PEAK1, and NRBP1, for T2DM treatment. Similarly, targeting seven druggable genes, namely ERBB3, C4B, CD69, PTPN22, IL27, ATP2A1, and LT-β, has The potential therapeutic benefits of T1DM treatment. This will provide new ideas for the treatment of diabetes and also help to determine the priority of drug development for diabetes.

Protection of β cells against pro-inflammatory cytokine stress by the GDF15-ERBB2 signaling

Aim/hypothesis

Growth/differentiation factor 15 (GDF15) is a therapeutic target for a variety of metabolic diseases, including type 1 diabetes (T1D). However, the nausea caused by GDF15 is a challenging point for therapeutic development. In addition, it is unknown why the endogenous GDF15 fails to protect from T1D development. Here, we investigate the GDF15 signaling in pancreatic islets towards opening possibilities for therapeutic targeting in β cells and to understand why this protection fails to occur naturally.

Methods

GDF15 signaling in islets was determined by proximity-ligation assay, untargeted proteomics, pathway analysis, and treatment of cells with specific inhibitors. To determine if GDF15 levels would increase prior to disease onset, plasma levels of GDF15 were measured in a longitudinal prospective study of children during T1D development (n=132 cases vs. n=40 controls) and in children with islet autoimmunity but normoglycemia (n=47 cases vs. n=40 controls) using targeted mass spectrometry. We also investigated the regulation of GDF15 production in islets by fluorescence microscopy and western blot analysis.

Results

The proximity-ligation assay identified ERBB2 as the GDF15 receptor in islets, which was confirmed using its specific antagonist, tucatinib. The untargeted proteomics analysis and caspase assay showed that ERBB2 activation by GDF15 reduces β cell apoptosis by downregulating caspase 8. In plasma, GDF15 levels were higher (p=0.0024) during T1D development compared to controls, but not in islet autoimmunity with normoglycemia. However, in the pancreatic islets GDF15 was depleted via sequestration of its mRNA into stress granules, resulting in translation halting.

Conclusions/interpretation

GDF15 protects against T1D via ERBB2-mediated decrease of caspase 8 expression in pancreatic islets. Circulating levels of GDF15 increases pre-T1D onset, which is insufficient to promote protection due to its localized depletion in the islets. These findings open opportunities for targeting GDF15 downstream signaling for pancreatic β cell protection in T1D and help to explain the lack of natural protection by the endogenous protein.

Deconstructing a Syndrome: Genomic Insights Into PCOS Causal Mechanisms and Classification

Polycystic ovary syndrome (PCOS) is among the most common disorders in women of reproductive age, affecting up to 15% worldwide, depending on the diagnostic criteria. PCOS is characterized by a constellation of interrelated reproductive abnormalities, including disordered gonadotropin secretion, increased androgen production, chronic anovulation, and polycystic ovarian morphology. It is frequently associated with insulin resistance and obesity. These reproductive and metabolic derangements cause major morbidities across the lifespan, including anovulatory infertility and type 2 diabetes (T2D). Despite decades of investigative effort, the etiology of PCOS remains unknown. Familial clustering of PCOS cases has indicated a genetic contribution to PCOS. There are rare Mendelian forms of PCOS associated with extreme phenotypes, but PCOS typically follows a non-Mendelian pattern of inheritance consistent with a complex genetic architecture, analogous to T2D and obesity, that reflects the interaction of susceptibility genes and environmental factors. Genomic studies of PCOS have provided important insights into disease pathways and have indicated that current diagnostic criteria do not capture underlying differences in biology associated with different forms of PCOS. We provide a state-of-the-science review of genetic analyses of PCOS, including an overview of genomic methodologies aimed at a general audience of non-geneticists and clinicians. Applications in PCOS will be discussed, including strengths and limitations of each study. The contributions of environmental factors, including developmental origins, will be reviewed. Insights into the pathogenesis and genetic architecture of PCOS will be summarized. Future directions for PCOS genetic studies will be outlined.

The rs705708 A allele of the ERBB3 gene is associated with lower prevalence of diabetic retinopathy and arterial hypertension and with improved renal function in type 1 diabetic patients

INTRODUCTION

The Erb-b2 receptor tyrosine kinase 3 (ERBB3) is involved in autoimmune processes related to type 1 diabetes mellitus (T1DM) pathogenesis. Accordingly, some studies have suggested that single nucleotide polymorphisms (SNPs) in the ERBB3 gene confer risk for T1DM. Proliferation-associated protein 2G4 (PA2G4) is another candidate gene for this disease because it regulates cell proliferation and adaptive immunity. Moreover, PA2G4 regulates ERBB3. To date, no study has evaluated the association of PA2G4 SNPs and T1DM.

AIM

To evaluate the association of ERBB3 rs705708 (G/A) and PA2G4 rs773120 (C/T) SNPs with T1DM and its clinical and laboratory characteristics.

METHODS

This case-control study included 976 white subjects from Southern Brazil, categorized into 501 cases with T1DM and 475 non-diabetic controls. The ERBB3 and PA2G4 SNPs were genotyped by allelic discrimination-real-time PCR.

RESULTS

ERBB3 rs705708 and PA2G4 rs773120 SNPs were not associated with T1DM considering different inheritance models and also when controlling for covariables. However, T1DM patients carrying the ERBB3 rs705708 A allele developed T1DM at an earlier age vs. G/G patients. Interestingly, in the T1DM group, the rs705708 A allele was associated with lower prevalence of diabetic retinopathy and arterial hypertension as well as with improved renal function (higher estimated glomerular filtration rate and lower urinary albumin excretion levels) compared to G/G patients.

CONCLUSIONS

Although no association was observed between the ERBB3 rs705708 and PA2G4 rs773120 SNPs and T1DM, the rs705708 A allele was associated, for the first time in literature, with lower prevalence of diabetic retinopathy and arterial hypertension. Additionally, this SNP was associated with improved renal function.

Genetic variation at ERBB3/IKZF4 and sexual dimorphism in epitope spreading in single autoantibody-positive relatives

AIMS/HYPOTHESIS

We examined whether the non-HLA susceptibility locus ERBB3/IKZF4 influences progression of type 1 diabetes stage specifically according to sex.

METHODS

SNPs of ERBB3 (rs2292239 T/G) and IKZF4 (rs1701704 G/T) were screened by allelic discrimination quantitative PCR assay in first-degree relatives of type 1 diabetes patients who had developed at least one circulating autoantibody. The effect of ERBB3/IKZF4 genotypes and sex, on the progression of single autoantibody positivity to multiple autoantibody positivity and from multiple autoantibody positivity to diabetes, was studied by Kaplan-Meier analysis and multivariate Cox regression.

RESULTS

In the cohort of autoantibody-positive first-degree relatives, the risk allele frequencies for ERBB3 rs2292239 (T) and IKZF4 rs1701704 (G) were increased. There was a significant male excess at the stage of multiple autoantibody positivity (p = 0.021). In Kaplan-Meier survival analysis, progression from single to multiple antibody positivity was delayed in female participants with genotype ERBB3 GG (p = 0.018, vs ERBB3 TG+TT) or IKZF4 TT (p = 0.023, vs IKZF4 GT+GG), but not in male participants. In multivariate Cox regression models, the interaction effects between female sex and ERBB3 GG (p = 0.012; HR = 0.305 [95% CI 0.120, 0.773]) or between female sex and IKZF4 TT (p = 0.011; HR = 0.329 [95% CI 0.140, 0.777]) emerged as potential determinants of delayed progression to multiple autoantibodies. The progression from multiple autoantibody positivity to type 1 diabetes appeared not to be influenced by ERBB3/IKZF4.

CONCLUSIONS/INTERPRETATION

In siblings and offspring of type 1 diabetes patients, polymorphism in region ERBB3/IKZF4 may affect disease progression at the level of epitope spreading in female individuals. Our findings suggest that interaction between sex and ERBB3/IKZF4 may contribute to the post-pubertal male excess in type 1 diabetes.

Low-dose interleukin-2-loaded nanoparticle effect on NK and T-reg cell expression in experimentally induced type 1 diabetes mellitus

Introduction

Type 1 diabetes mellitus is an autoimmune disorder characterized by inflammatory damage to pancreatic β cells resulting in loss of insulin secretion. In autoimmune type 1 diabetes mellitus (T1D) natural killer cells (NK) initiate pancreatic islets cell lyses in autoimmune T1D. Loss of T regulatory cells (Treg) at disease onset facilitates the activation and accumulation of NKs in the pancreatic microenvironment. A proper low-dose interleukin 2 (IL-2) could enhance Tregs and enforce control and regulation of pro-inflammatory NKs.

Aim

This relation needs to be studied to improve therapeutic strategies aimed at resetting the balance between Tregs and proinflammatory cells.

Material and methods

We used novel formulations of low-dose IL-2 loaded on chitosan nanoparticles. The study included 116 T1D BALB/c mice experimentally induced by streptozotocin, divided into groups. Their splenocytes were maintained in a short-term culture for assessment of expression of CD4+FOXP3+ Treg and NKp46+NK by both flow cytometry and enzyme-linked immunoassay (ELISA). Morphological, immunohistochemical, and morphometrical analyses were done.In vitro suppressor assay was used to assess the suppressor effect of Treg cells after exogenous IL-2 treatment.

Results

NK cell expression, NKp46 level, and NK cell functions were modulated more in mice injected with IL-2-loaded chitosan nanoparticles than in other groups. A statistical inverse correlation was found between Treg and NK cell expression in IL-2-loaded chitosan with 0.3 µIU (p = 0.047), and this correlation was related to FOXP3 expression on Treg cells. The modified expression of NK and NKp46 was noticed in mice injected with 0.3 µIU for longer duration (3 weeks) (p < 0.001), but the NK functions did not show any significant changes with prolonged treatment.

Conclusions

Prolonged administration of low-dose IL-2 results in the vigorous expression of NKp46, indicating a significant role of Tregs in NK stimulation and motivation. Low-dose IL-2 selectively modulates NKp46 NK and FOXP3+ Tregs and increases their expression.

Study of long non-coding RNA and mitochondrial dysfunction in diabetic rats

Diabetes mellitus (DM) is a worldwide health problem. The Micro- and macro-vascular complications are the major causes of morbidity and mortality of DM. Molecular regulation of mitochondrial fission/fusion cycles is being studied, but the results were not conclusive. The aim of this study is to investigate the possible functional role of lncRNA H19 and its relation to mitofusin-2 (Mfn-2) gene expression in diabetic rats with cardiac and renal complications. Streptozotocin-induced diabetic male, albino rats and a matched control group were investigated. Cardiac weights, blood pressure and ECG were recorded. Biochemical evaluation of cardiac and renal functions was performed. Molecular determination of lncRNA H19 and Mfn-2 gene expression and histological examination by light and electron microscopy for cardiac and renal tissues were performed. Diabetic rats showed a significant increase of left ventricle weight/whole body weight ratio, R wave voltage, and a significant decrease of blood pressure, heart rate, and P wave voltage. At the molecular level, lncRNA H19 and Mfn-2 mRNA showed altered expression with a statistically significant downregulation of Mfn-2 mRNA expression in renal tissues. In conclusion, the changes in lncRNA H19 and Mfn-2 mRNA expression may help better understanding of the pathogenesis of cardiac and renal dysfunctions associated with type 1 DM.

Long non-coding RNA-regulated pathways in pancreatic β cells: Their role in diabetes

Long non-coding RNAs (lncRNAs) are transcripts of more than 200 nucleotides that have not coding potential, but act as gene expression regulators through several molecular mechanisms. Several studies have identified tons of lncRNAs that are expressed in pancreatic β cells and many of them have been shown to have β cell-specific expression, suggesting a potential role in the regulation of basal β cell functions. Indeed, accumulating evidence based on numerous studies, has highlighted the implication of lncRNAs in the regulation of pancreatic β cell differentiation and proliferation, insulin synthesis and secretion, and apoptosis. In addition, several lncRNAs have shown to be implicated in pancreatic β cell dysfunction linked to different types of diabetes, including type 1 and type 2 diabetes, and monogenic forms of the disease. Pathogenic conditions linked to diabetes (inflammation or lipoglucotoxicity, for example) dysregulate the expression of several lncRNAs, suggesting that changes in lncRNA may alter potentially important pathways for β cell function, and eventually leading to β cell dysfunction and diabetes development. In this sense, functional characterization of some lncRNAs has demonstrated that these non-coding molecules participate in the regulation of several crucial pathways at the pancreatic β cell level, and dysregulation of these pathways leads to pathogenic phenotypes. In this review, we provide an overview of the action mechanisms of functionally characterized lncRNAs in healthy β cells and describe the contribution of some diabetes-associated lncRNAs to pancreatic β cell failure.

Long Non-Coding RNAs as Key Modulators of Pancreatic β-Cell Mass and Function

Numerous studies have sought to decipher the genetic and other mechanisms contributing to β-cell loss and dysfunction in diabetes mellitus. However, we have yet to fully understand the etiology of the disease or to develop satisfactory treatments. Since the majority of diabetes susceptibility loci are mapped to non-coding regions within the genome, understanding the functions of non-coding RNAs in β-cell biology might provide crucial insights into the pathogenesis of type 1 (T1D) and type 2 (T2D) diabetes. During the past decade, numerous studies have indicated that long non-coding RNAs play important roles in the maintenance of β-cell mass and function. Indeed, lncRNAs have been shown to be involved in controlling β-cell proliferation during development and/or β-cell compensation in response to hyperglycaemia. LncRNAs such as TUG-1 and MEG3 play a role in both β-cell apoptosis and function, while others sensitize β-cells to apoptosis in response to stress signals. In addition, several long non-coding RNAs have been shown to regulate the expression of β-cell-enriched transcription factors in cis or in trans. In this review, we provide an overview of the roles of lncRNAs in maintaining β-function and mass, and discuss their relevance in the development of diabetes.

Effect of low dose IL-2 loaded chitosan nanoparticles on natural killer and regulatory T cell expression in experimentally induced autoimmune type 1 diabetes mellitus

Introduction

Natural killer cells (NK) initiate pancreatic islets cell lyses in autoimmune type 1 diabetes mellitus (T1D). Loss of T regulatory cells (Treg) at disease onset facilitates activation and accumulation of NKs in the pancreatic microenvironment. A proper low dose interleukin 2 (IL-2) could enhance Tregs and enforce control and regulation of pro-inflammatory NKs. This relation needs to be studied to improve therapeutic strategies aimed at resetting the balance between Tregs and proinflammatory cells.

Material and methods

We used novel formulations of low dose IL-2 loaded on chitosan nanoparticles. The study included 116 T1D BALB/c mice experimentally induced by streptozotocin, divided into groups. Their splenocytes were maintained in a short-term culture for assessment of expression of CD4⁺Foxp3⁺ Treg and NKp46⁺NK by both flow cytometry and enzyme linked immunoassay (ELISA). In vitro suppressor-assay was used in order to assess the suppressor effect of Treg cells after exogenous IL-2 treatment.

Results

NK cell expression, NKp46 level and NK cell functions were modulated in mice injected with IL-2 loaded chitosan nanoparticles than other groups. A statistical inverse correlation was found between Treg and NK cell expression in IL-2 loaded chitosan with (0.3 µIU) (p = 0.047) and this correlation was related to Foxp3 expression on Treg cells. The modified expression of NK and NKp46 was noticed in mice injected with (0.3 µIU) for longer duration (three weeks) (p < 0.001) but the NK functions did not show any significant changes with prolonged treatment.

Conclusions

Low dose (0.3) µIU IL-2 nanoparticles effectively modulated NK and NKp46 expression. It selectively modulates the suppressive activity of Tregs indicating a significant role of Tregs in NK activation and function by controlling the availability of IL-2 in the microenvironment.

The Rac2 GTPase contributes to cathepsin H-mediated protection against cytokine-induced apoptosis in insulin-secreting cells

The type 1 diabetes (T1D) risk locus on chromosome 15q25.1 harbors the candidate gene CTSH (cathepsin H). We previously demonstrated that CTSH regulates β-cell function in vitro and in vivo. CTSH overexpression protected insulin-secreting INS-1 cells against cytokine-induced apoptosis. The purpose of the present study was to identify the genes through which CTSH mediates its protective effects. Microarray analysis identified 63 annotated genes differentially expressed between CTSH-overexpressing INS-1 cells and control cells treated with interleukin-1β and interferon-γ for up to 16h. Permutation test identified 10 significant genes across all time-points: Elmod1, Fam49a, Gas7, Gna15, Msrb3, Nox1, Ptgs1, Rac2, Scn7a and Ttn. Pathway analysis identified the "Inflammation mediated by chemokine and cytokine signaling pathway" with Gna15, Ptgs1 and Rac2 as significant. Knockdown of Rac2 abolished the protective effect of CTSH overexpression on cytokine-induced apoptosis, suggesting that the small GTPase and T1D candidate gene Rac2 contributes to the anti-apoptotic effect of CTSH.

Diabetes Mellitus Is a Chronic Disease that Can Benefit from Therapy with Induced Pluripotent Stem Cells

Diabetes mellitus (DM) is one of the main causes of morbidity and mortality, with an increasing incidence worldwide. The impact of DM on public health in developing countries has triggered alarm due to the exaggerated costs of the treatment and monitoring of patients with this disease. Considerable efforts have been made to try to prevent the onset and reduce the complications of DM. However, because insulin-producing pancreatic β-cells progressively deteriorate, many people must receive insulin through subcutaneous injection. Additionally, current therapies do not have consistent results regarding the prevention of chronic complications. Leveraging the approval of real-time continuous glucose monitors and sophisticated algorithms that partially automate insulin infusion pumps has improved glycemic control, decreasing the burden of diabetes management. However, these advances are facing physiologic barriers. New findings in molecular and cellular biology have produced an extraordinary advancement in tissue development for the treatment of DM. Obtaining pancreatic β-cells from somatic cells is a great resource that currently exists for patients with DM. Although this therapeutic option has great prospects for patients, some challenges remain for this therapeutic plan to be used clinically. The purpose of this review is to describe the new techniques in cell biology and regenerative medicine as possible treatments for DM. In particular, this review highlights the origin of induced pluripotent cells (iPSCs) and how they have begun to emerge as a regenerative treatment that may mitigate the pathology of this disease.

The heterogeneous pathogenesis of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) results from the destruction of pancreatic β-cells that is mediated by the immune system. Multiple genetic and environmental factors found in variable combinations in individual patients are involved in the development of T1DM. Genetic risk is defined by the presence of particular allele combinations, which in the major susceptibility locus (the HLA region) affect T cell recognition and tolerance to foreign and autologous molecules. Multiple other loci also regulate and affect features of specific immune responses and modify the vulnerability of β-cells to inflammatory mediators. Compared with the genetic factors, environmental factors that affect the development of T1DM are less well characterized but contact with particular microorganisms is emerging as an important factor. Certain infections might affect immune regulation, and the role of commensal microorganisms, such as the gut microbiota, are important in the education of the developing immune system. Some evidence also suggests that nutritional factors are important. Multiple islet-specific autoantibodies are found in the circulation from a few weeks to up to 20 years before the onset of clinical disease and this prediabetic phase provides a potential opportunity to manipulate the islet-specific immune response to prevent or postpone β-cell loss. The latest developments in understanding the heterogeneity of T1DM and characterization of major disease subtypes might help in the development of preventive treatments.

The Association between rs2292239 Polymorphism in ERBB3 Gene and Type 1 Diabetes: A Meta-Analysis

Objectives

The purpose of this study was to explore the association between rs2292239 polymorphism in ERBB3 gene and type 1 diabetes (T1D).

Methods

A systematic search of studies on the association of rs2292239 polymorphism in ERBB3 gene with T1D susceptibility was conducted in PubMed, Web of science, Elsevier Science Direct, and Cochrane Library. Eventually, 9 published studies were included. The strength of association between rs2292239 polymorphism and T1D susceptibility was assessed by odds ratios (ORs) with its 95% confidence intervals (CIs).

Results

A total of 9 case-control studies, consisting of 5369 T1D patients and 6920 controls, were included in the meta-analysis. This meta-analysis showed significant association between ERBB3 rs2292239 polymorphism and T1D susceptibility in overall population (A vs. C, OR: 1.292, 95% CI= 1.224-1.364, P _H=0.450, P _H is P value for the heterogeneity test). Similar results were found in subgroup analysis by ethnicity.

Conclusions

ERBB3 rs2292239 polymorphism is associated with T1D susceptibility and rs2292239-A allele is a risk factor for T1D. However, more large-scale studies are warranted to replicate our findings.

Natural compounds acting at P2 receptors alleviate peripheral neuropathy

Neuropathic pain is generally resistant to currently available treatments, and it is often a consequence of nerve injury due to surgery, diabetes or infection. Myocardial ischemic nociceptive signaling increases the sympathoexcitatory reflex to aggravate myocardial injury. Elucidation of the pathogenetic factors might provide a target for optimal treatment. Abundant evidence in the literature suggests that P2X and P2Y receptors play important roles in signal transmission. Traditional Chinese medicines, such as emodin, puerarin and resveratrol, antagonize nociceptive transmission mediated by purinergic 2 (P2) receptors in primary afferent neurons. This review summarizes recently published data on P2 receptor-mediated neuropathic pain and myocardial ischemia in dorsal root ganglia (DRG), superior cervical ganglia (SCG) and stellate ganglia (SG), with a special focus on the beneficial role of natural compounds.

A systematic review of non-genetic predictors and genetic factors of glycated haemoglobin in type 1 diabetes one year after diagnosis

Type 1 diabetes (T1D) results from autoimmune destruction of the pancreatic βcells. Although all T1D patients require daily administration of exogenous insulin, their insulin requirement to achieve good glycaemic control may vary significantly. Glycated haemoglobin (HbA1c) level represents a stable indicator of glycaemic control and is a reliable predictor of long-term complications of T1D. The purpose of this article is to systematically review the role of non-genetic predictors and genetic factors of HbA1c level in T1D patients after the first year of T1D, to exclude the honeymoon period. A total of 1974 articles published since January 2011 were identified and 78 were finally included in the analysis of non-genetic predictors. For genetic factors, a total of 277 articles were identified and 14 were included. The most significantly associated factors with HbA1c level are demographic (age, ethnicity, and socioeconomic status), personal (family characteristics, parental care, psychological traits...) and features related to T1D (duration of T1D, adherence to treatment …). Only a few studies have searched for genetic factors influencing HbA1c level, most of which focused on candidate genes using classical genetic statistical methods, with generally limited power and incomplete adjustment for confounding factors and multiple testing. Our review shows the complexity of explaining HbA1c level variations, which involves numerous correlated predictors. Overall, our review underlines the lack of studies investigating jointly genetic and non-genetic factors and their interactions to better understand factors influencing glycaemic control for T1D patients.

Investigating genetic-and-epigenetic networks, and the cellular mechanisms occurring in Epstein-Barr virus-infected human B lymphocytes via big data mining and genome-wide two-sided NGS data identification

Epstein-Barr virus (EBV), also known as human herpesvirus 4, is prevalent in all human populations. EBV mainly infects human B lymphocytes and epithelial cells, and is therefore associated with their various malignancies. To unravel the cellular mechanisms during the infection, we constructed interspecies networks to investigate the molecular cross-talk mechanisms between human B cells and EBV at the first (0-24 hours) and second (8-72 hours) stages of EBV infection. We first constructed a candidate genome-wide interspecies genetic-and-epigenetic network (the candidate GIGEN) by big database mining. We then pruned false positives in the candidate GIGEN to obtain the real GIGENs at the first and second infection stages in the lytic phase by their corresponding next-generation sequencing data through dynamic interaction models, the system identification approach, and the system order detection method. The real GIGENs are very complex and comprise protein-protein interaction networks, gene/microRNA (miRNA)/long non-coding RNA regulation networks, and host-virus cross-talk networks. To understand the molecular cross-talk mechanisms underlying EBV infection, we extracted the core GIGENs including host-virus core networks and host-virus core pathways from the real GIGENs using the principal network projection method. According to the results, we found that the activities of epigenetics-associated human proteins or genes were initially inhibited by viral proteins and miRNAs, and human immune responses were then dysregulated by epigenetic modification. We suggested that EBV exploits viral proteins and miRNAs, such as EBNA1, BPLF1, BALF3, BVRF1 and miR-BART14, to develop its defensive mechanism to defeat multiple immune attacks by the human immune system, promotes virion production, and facilitates the transportation of viral particles by activating the human genes NRP1 and CLIC5. Ultimately, we propose a therapeutic intervention comprising thymoquinone, valpromide, and zebularine to act as inhibitors of EBV-associated malignancies.

Islet Long Noncoding RNAs: A Playbook for Discovery and Characterization

Diabetes is a complex group of metabolic disorders that can be accompanied by several comorbidities, including increased risk of early death. Decades of diabetes research have elucidated many genetic drivers of normal islet function and dysfunction; however, a lack of suitable treatment options suggests our knowledge about the disease remains incomplete. The establishment of long noncoding RNAs (lncRNAs), once dismissed as "junk" DNA, as essential gene regulators in many biological processes has redefined the central role for RNA in cells. Studies showing that misregulation of lncRNAs can lead to disease have contributed to the emergence of lncRNAs as attractive candidates for drug targeting. These findings underscore the need to reexamine islet biology in the context of a regulatory role for RNA. This review will 1) highlight what is known about lncRNAs in the context of diabetes, 2) summarize the strategies used in lncRNA discovery pipelines, and 3) discuss future directions and the potential impact of studying the role of lncRNAs in diabetes.

Deciphering Non-coding RNAs in Cardiovascular Health and Disease

After being long considered as “junk” in the human genome, non-coding RNAs (ncRNAs) currently represent one of the newest frontiers in cardiovascular disease (CVD) since they have emerged in recent years as potential therapeutic targets. Different types of ncRNAs exist, including small ncRNAs that have fewer than 200 nucleotides, which are mostly known as microRNAs (miRNAs), and long ncRNAs that have more than 200 nucleotides. Recent discoveries on the role of ncRNAs in epigenetic and transcriptional regulation, atherosclerosis, myocardial ischemia/reperfusion (I/R) injury and infarction (MI), adverse cardiac remodeling and hypertrophy, insulin resistance, and diabetic cardiomyopathy prompted vast interest in exploring candidate ncRNAs for utilization as potential therapeutic targets and/or diagnostic/prognostic biomarkers in CVDs. This review will discuss our current knowledge concerning the roles of different types of ncRNAs in cardiovascular health and disease and provide some insight on the cardioprotective signaling pathways elicited by the non-coding genome. We will highlight important basic and clinical breakthroughs that support employing ncRNAs for treatment or early diagnosis of a variety of CVDs, and also depict the most relevant limitations that challenge this novel therapeutic approach.

Long non-coding RNAs in rheumatoid arthritis

Rheumatoid arthritis, a disabling autoimmune disease, is associated with altered gene expression in circulating immune cells and synovial tissues. Accumulating evidence has suggested that long non-coding RNAs (lncRNAs), which modulate gene expression through multiple mechanisms, are important molecules involved in immune and inflammatory pathways. Importantly, many studies have reported that lncRNAs can be utilized as biomarkers for disease diagnosis and prognostication. Recently, dysregulation of lncRNAs in rheumatoid arthritis and other autoimmune diseases has been revealed. Experimental studies also confirmed their crosstalk with matrix metalloproteinases, nuclear factor-κB signalling and T-cell response pertinent to autoimmunity and inflammation. Circulating lncRNAs, such as HOTAIR, differentiated patients with rheumatoid arthritis from healthy subjects. Taken together, lncRNAs are good candidates as biomarkers and therapeutic targets in rheumatoid arthritis. Further investigation on in vivo delivery of these regulatory molecules and large-cohort validation of their clinical applicability may be useful.

On type 1 diabetes mellitus pathogenesis

Type 1 diabetes mellitus (T1DM) results from the autoimmune destruction of β cells of the endocrine pancreas. Pathogenesis of T1DM is different from that of type 2 diabetes mellitus, where both insulin resistance and reduced secretion of insulin by the β cells play a synergistic role. We will present genetic, environmental and immunologic factors that destroy β cells of the endocrine pancreas and lead to insulin deficiency. The process of autoimmune destruction takes place in genetically susceptible individuals under the triggering effect of one or more environmental factors and usually progresses over a period of many months to years, during which period patients are asymptomatic and euglycemic, but positive for relevant autoantibodies. Symptomatic hyperglycemia and frank diabetes occur after a long latency period, which reflects the large percentage of β cells that need to be destroyed before overt diabetes become evident.

The Big Entity of New RNA World: Long Non-Coding RNAs in Microvascular Complications of Diabetes

A major part of the genome is known to be transcribed into non-protein coding RNAs (ncRNAs), such as microRNA and long non-coding RNA (lncRNA). The importance of ncRNAs is being increasingly recognized in physiological and pathological processes. lncRNAs are a novel class of ncRNAs that do not code for proteins and are important regulators of gene expression. In the past, these molecules were thought to be transcriptional "noise" with low levels of evolutionary conservation. However, recent studies provide strong evidence indicating that lncRNAs are (i) regulated during various cellular processes, (ii) exhibit cell type-specific expression, (iii) localize to specific organelles, and (iv) associated with human diseases. Emerging evidence indicates an aberrant expression of lncRNAs in diabetes and diabetes-related microvascular complications. In the present review, we discuss the current state of knowledge of lncRNAs, their genesis from genome, and the mechanism of action of individual lncRNAs in the pathogenesis of microvascular complications of diabetes and therapeutic approaches.

The rs2292239 polymorphism in ERBB3 gene is associated with risk for type 1 diabetes mellitus in a Brazilian population

The Erb-b2 receptor tyrosine kinase 3 (ERBB3) belongs to a family of epidermal growth factor receptors of protein tyrosine kinases, and regulates cell survival, differentiation and proliferation in several cell types. Previous studies have suggested that ERBB3 contributes to T1DM pathogenesis by modulating antigen presenting cell function, autoimmunity and cytokine-induced beta-cell apoptosis. Accordingly, some genome-wide association studies identified ERBB3 gene as a susceptibility locus for T1DM, with the strongest association signal being observed for the rs2292239 single nucleotide polymorphism (SNP) in intron 7 of the gene. Therefore, the aim of the present study was to replicate the association of the ERBB3 rs2292239 SNP with T1DM in a Brazilian population. We analyzed 421 T1DM patients (cases) and 510 nondiabetic subjects (controls). All subjects were self-declared as white. The ERBB3 rs2292239 (A/C) SNP was genotyped by real-time PCR using TaqMan MGB probes. Genotype (P=0.001) and allele (P=0.002) frequencies of the ERBB3 rs2292239 SNP were differently distributed between T1DM patients and nondiabetic controls. Moreover, the A allele was significantly associated with risk for T1DM when considering recessive (OR=1.58, 95% CI 1.11-2.27; P=0.015), additive (OR=1.78, 95% CI 1.21-2.62; P=0.004), and dominant (OR=1.39, 95% CI 1.07-1.81; P=0.016) models of inheritance. However, after adjustment for presence of high-risk HLA DR/DQ genotypes, the rs2292239 SNP remained independently associated with T1DM only for the additive model (OR=1.62, 95% CI 1.02-2.59; P=0.043). Our results suggest that the A/A genotype of the ERBB3 rs2292239 SNP is associated with risk for T1DM in a white Brazilian population.

LncRNAs: key players and novel insights into diabetes mellitus

Long non-coding RNAs (LncRNAs) are a class of endogenous RNA molecules, which have a transcribing length of over 200 nt, lack a complete functional open reading frame (ORF), and rarely encode a functional short peptide. Recent studies have revealed that disruption of LncRNAs levels correlates with several human diseases, including diabetes mellitus (DM), a complex multifactorial metabolic disorder affecting more than 400 million people worldwide. LncRNAs are emerging as pivotal regulators in various biological processes, in the progression of DM and its associated complications, involving pancreatic β-cell disorder, insulin resistance, and epigenetic regulation, etc. Further investigation into the mechanisms of action of LncRNAs in DM will be of great value in the thorough understanding of pathogenesis. However, prior to successful application of LncRNAs, further search for molecular biomarkers and drug targets to provide a new strategy for DM prevention, early diagnosis, and therapy is warranted.

Long non-coding RNAs as novel players in β cell function and type 1 diabetes

Background

Long non-coding RNAs (lncRNAs) are a sub-class within non-coding RNA repertoire that have emerged as crucial regulators of the gene expression in various pathophysiological conditions. lncRNAs display remarkable versatility and wield their functions through interactions with RNA, DNA, or proteins. Accumulating body of evidence based on multitude studies has highlighted the role of lncRNAs in many autoimmune and inflammatory diseases, including type 1 diabetes (T1D).

Main body of abstract

This review highlights emerging roles of lncRNAs in immune and islet β cell function as well as some of the challenges and opportunities in understanding the pathogenesis of T1D and its complications.

Conclusion

We accentuate that the lncRNAs within T1D-loci regions in consort with regulatory variants and enhancer clusters orchestrate the chromatin remodeling in β cells and thereby act as cis/trans-regulatory determinants of islet cell transcriptional programs.

Type 1 Diabetes Candidate Genes Linked to Pancreatic Islet Cell Inflammation and Beta-Cell Apoptosis

Type 1 diabetes (T1D) is a chronic immune-mediated disease resulting from the selective destruction of the insulin-producing pancreatic islet β-cells. Susceptibility to the disease is the result of complex interactions between environmental and genetic risk factors. Genome-wide association studies (GWAS) have identified more than 50 genetic regions that affect the risk of developing T1D. Most of these susceptibility loci, however, harbor several genes, and the causal variant(s) and gene(s) for most of the loci remain to be established. A significant part of the genes located in the T1D susceptibility loci are expressed in human islets and β cells and mounting evidence suggests that some of these genes modulate the β-cell response to the immune system and viral infection and regulate apoptotic β-cell death. Here, we discuss the current status of T1D susceptibility loci and candidate genes with focus on pancreatic islet cell inflammation and β-cell apoptosis.

Genetic risk factors for type 1 diabetes

Type 1 diabetes is diagnosed at the end of a prodrome of β-cell autoimmunity. The disease is most likely triggered at an early age by autoantibodies primarily directed against insulin or glutamic acid decarboxylase, or both, but rarely against islet antigen-2. After the initial appearance of one of these autoantibody biomarkers, a second, third, or fourth autoantibody against either islet antigen-2 or the ZnT8 transporter might also appear. The larger the number of β-cell autoantibody types, the greater the risk of rapid progression to clinical onset of diabetes. This association does not necessarily mean that the β-cell autoantibodies are pathogenic, but rather that they represent reproducible biomarkers of the pathogenesis. The primary risk factor for β-cell autoimmunity is genetic, mainly occurring in individuals with either HLA-DR3-DQ2 or HLA-DR4-DQ8 haplotypes, or both, but a trigger from the environment is generally needed. The pathogenesis can be divided into three stages: 1, appearance of β-cell autoimmunity, normoglycaemia, and no symptoms; 2, β-cell autoimmunity, dysglycaemia, and no symptoms; and 3, β-cell autoimmunity, dysglycaemia, and symptoms of diabetes. The genetic association with each one of the three stages can differ. Type 1 diabetes could serve as a disease model for organ-specific autoimmune disorders such as coeliac disease, thyroiditis, and Addison's disease, which show similar early markers of a prolonged disease process before clinical diagnosis.