Pathogenesis Of Type 1 Diabetes Research Articles

Gene Expression Signatures Reveal Common Virus Infection Pathways in Target Tissues of Type 1 Diabetes, Hashimoto's Thyroiditis, and Celiac Disease.

Type 1 diabetes (T1D) patients are at heightened risk for other autoimmune disorders, particularly Hashimoto’s thyroiditis (HT) and celiac disease (CD). Recent evidence suggests that target tissues of autoimmune diseases engage in a harmful dialogue with the immune system. However, it is unclear whether shared mechanisms drive similar molecular signatures at the target tissues among T1D, HT, and CD. In our current study, microarray datasets were obtained and mined to identify gene signatures from disease-specific targeted tissues including the pancreas, thyroid, and intestine from individuals with T1D, HT, and CD, as well as their matched controls. Further, the threshold-free algorithm rank-rank hypergeometric overlap analysis (RRHO) was used to compare the genomic signatures of the target tissues of the three autoimmune diseases. Next, promising drugs that could potentially reverse the observed signatures in patients with two or more autoimmune disorders were identified using the cloud-based CLUE software platform. Finally, microarray data of auto-antibody positive individuals but not diagnosed with T1D and single cell sequencing data of patients with T1D and HT were used to validate the shared transcriptomic fingerprint. Our findings revealed significant common gene expression changes in target tissues of the three autoimmune diseases studied, many of which are associated with virus infections, including influenza A, human T-lymphotropic virus type 1, and herpes simplex infection. These findings support the importance of common environmental factors in the pathogenesis of T1D, HT, and CD.

Selenium and Selenoproteins at the Intersection of Type 2 Diabetes and Thyroid Pathophysiology.

Type 2 diabetes (T2D) is considered one of the largest global public-health concerns, affecting approximately more than 400 million individuals worldwide. The pathogenesis of T2D is very complex and, among the modifiable risk factors, selenium (Se) has recently emerged as a determinant of T2D pathogenesis and progression. Selenium is considered an essential element with antioxidant properties, and is incorporated into the selenoproteins involved in the antioxidant response. Furthermore, deiodinases, the enzymes responsible for homeostasis and for controlling the activity of thyroid hormones (THs), contain Se. Given the crucial action of oxidative stress in the onset of insulin resistance (IR) and T2D, and the close connection between THs and glucose metabolism, Se may be involved in these fundamental relationships; it may cover a dual role, both as a protective factor and as a risk factor of T2D, depending on its basal plasma concentration and the individual’s diet intake. In this review we discuss the current evidence (from experimental, observational and randomized clinical studies) on how Se is associated with the occurrence of T2D and its influence on the relationship between thyroid pathophysiology, IR and T2D.

Genome-Wide Identification of N6-Methyladenosine Associated SNPs as Potential Functional Variants for Type 1 Diabetes.

ObjectivesN6-methyladenosine (m6A) is essential in the regulation of the immune system, but the role that its single nucleotide polymorphisms (SNPs) play in the pathogenesis of type 1 diabetes (T1D) remains unknown. This study demonstrated the association between genetic variants in m6A regulators and T1D risk based on a case-control study in a Chinese population.MethodsThe tagging SNPs in m6A regulators were genotyped in 1005 autoantibody-positive patients with T1D and 1257 controls using the Illumina Human OmniZhongHua-8 platform. Islet-specific autoantibodies were examined by radioimmunoprecipitation in all the patients. The mixed-meal glucose tolerance test was performed on 355 newly diagnosed patients to evaluate their residual islet function. The functional annotations for the identified SNPs were performed in silico. Using 102 samples from a whole-genome expression microarray, key signaling pathways associated with m6A regulators in T1D were comprehendingly evaluated.ResultsUnder the additive model, we observed three tag SNPs in the noncoding region of the PRRC2A (rs2260051, rs3130623) and YTHDC2 (rs1862315) gene are associated with T1D risk. Although no association was found between these SNPs and islet function, patients carrying risk variants had a higher positive rate for ZnT8A, GADA, and IA-2A. Further analyses showed that rs2260051[T] was associated with increased expression of PRRC2A mRNA (P = 7.0E-13), and PRRC2A mRNA was significantly higher in peripheral blood mononuclear cell samples from patients with T1D compared to normal samples (P = 0.022). Enrichment analyses indicated that increased PRRC2A expression engages in the most significant hallmarks of cytokine-cytokine receptor interaction, cell adhesion and chemotaxis, and neurotransmitter regulation pathways. The potential role of increased PRRC2A in disrupting immune homeostasis is through the PI3K/AKT pathway and neuro-immune interactions.ConclusionThis study found intronic variants in PRRC2A and YTHDC2 associated with T1D risk in a Chinese Han population. PRRC2A rs2260051[T] may be implicated in unbalanced immune homeostasis by affecting the expression of PRRC2A mRNA. These findings enriched our understanding of m6A regulators and their intronic SNPs that underlie the pathogenesis of T1D.

اكتشاف جين جديد يساهم في الإصابة بمرض السكري ويؤثر في استقلاب الغلوكوز

الملخص المقدمة وهدف الدراسة: يعدّ مرض السكري من النوع الثاني مرضًا متعدد العوامل والجينات. وقد تم اكتشاف أكثر من 140 متغيرًا جينيًا وراثيًا مرتبطًا بسببية المرض، ولكنها تفسر فقط 10% من الأسباب الوراثية للسكري. لهذا، تسعى هذه الدراسة إلى استخدام نهج جديد تُحدَّد من خلاله جينات جديدة مشارِكة في فسيولوجية مرض السكري وإفراز الإنسولين. طريقة البحث: تم تحليل بيانات تسلسل الحمض النووي الريبوزي من جزر البنكرياس البشرية جُمعت من 89 متبرعًا. كما أُجريت سلسلة من التجارب الوظيفية في خلايا بيتا الحيوانية (INS-1) من الفئران للتحقق من الدور المحتمل للجين المرشح بما في ذلك تثبيط نشاطه، وإفراز الإنسولين، وحيوية الخلية، وموت الخلية المبرمج، والتعبير الجيني. النتائج: قد أظهر تحليل التعبير الجيني التفاضلي لبيانات تسلسل الحمض النووي الريبوزي أن 231 جينًا كان لها تعبير منخفض على نحو ملحوظ في جزر البنكرياس من المتبرعين المرضى بالسكري مقارنة بالأصحاء. وتم خفض عدد الجينات إلى 37 من جراء تطبيق قطع إحصائي أكثر صرامة. ومن بين تلك الجينات، تم اختيار (PPP1R1A) كجين مرشح بسبب ارتباطه القوي مع معدل السكري التراكمي، وتعبيره الجيني المرتفع في جزر البنكرياس البشرية مقارنة بباقي الجينات. وأيضًا، وُجد أن تعبير الجينات الوظيفية المهمة في خلايا بيتا مثل (INS) و(PDX1) و(GLUT2) و(INSR) انخفض على نحو كبير في الخلايا التي ثُبّط فيها نشاط (PPP1R1A). وخلصت الدراسة إلى أن (PPP1R1A) جين منظّم لوظيفة خلايا بيتا وإفراز الإنسولين، كما سلطت الضوء على قائمة من الجينات التي قد يكون لها دور وتأثير في مرض السكري. Background: Type 2 diabetes (T2D) is a multifactorial polygenic disease with an unclear causative mechanism. Close to 140 genetic variants are associated with T2D, but they only explain 10% of the heritability. Aim: In this study, we employed a novel approach to identify novel genes involved in the pathophysiology of T2D and insulin secretion. Methods: We analyzed RNA-sequencing data from human pancreatic islets at a global level. Furthermore, we performed a serial of functional experiments in rat pancreatic β-cells to validate the potential role of the candidate gene including siRNA silencing, insulin secretion, cell viability, apoptosis, QPCR, and western blot expression of the key molecule in β-cells. Results: Differential expression analysis reveals those 231 genes are significantly (P<0.05) downregulated in diabetic islets compared to nondiabetics. However, the number of genes was restricted to 37 genes by applying a cutoff of (P<0.01). Of these genes, PPP1R1A was selected as a candidate gene due to its strong correlation with HbA1c and high expression in human pancreatic islets. Silencing of PPP1R1A in INS-1 cells was markedly reduced, insulin secretion while cell viability and apoptosis were not affected. In addition, the expression of Insulin, PDX1, GLUT2, and INSR was significantly down-regulated in PPP1R1A-silenced cells. Expression of NEUROD1 and GCK was not affected. Conclusion: The study identifies PPP1R1A as a novel regulator of pancreatic β-cell function and insulin secretion. Moreover, it introduces a list of potential genes to be explored for their role in the pathogenesis of T2D.

Transcriptional regulatory networks of circulating immune cells in type 1 diabetes: A community knowledgebase

SummaryInvestigator-generated transcriptomic datasets interrogating circulating immune cell (CIC) gene expression in clinical type 1 diabetes (T1D) have underappreciated re-use value. Here, we repurposed these datasets to create an open science environment for the generation of hypotheses around CIC signaling pathways whose gain or loss of function contributes to T1D pathogenesis. We firstly computed sets of genes that were preferentially induced or repressed in T1D CICs and validated these against community benchmarks. We then inferred and validated signaling node networks regulating expression of these gene sets, as well as differentially expressed genes in the original underlying T1D case:control datasets. In a set of three use cases, we demonstrated how informed integration of these networks with complementary digital resources supports substantive, actionable hypotheses around signaling pathway dysfunction in T1D CICs. Finally, we developed a federated, cloud-based web resource that exposes the entire data matrix for unrestricted access and re-use by the research community.

Lymphotoxins Serve as a Novel Orchestrator in T1D Pathogenesis.

Type 1 diabetes (T1D) stems from pancreatic β cell destruction by islet reactive immune cells. Similar as other autoimmune disorders, there is no curative remedy for T1D thus far. Chronic insulitis is the hallmark of T1D, which creates a local inflammatory microenvironment that impairs β cell function and ultimately leads to β cell death. Immune regulation shows promise in T1D treatment by providing a time window for β cell recovery. However, due to the complex nature of T1D pathogenesis, the therapeutic effect of immune regulation is often short-lasting and unsatisfying in monotherapies. Lymphotoxins (LTs) were first identified in 1960s as the lymphocyte-producing cytokine that can kill other cell types. As a biological cousin of tumor necrosis factor alpha (TNFα), LTs play unique roles in T1D development. Herein in this review, we summarized the advancements of LTs in T1D pathogenesis. We particularly highlighted their effect on the formation of peri-islet tertiary lymphoid organs (TLOs), and discussed their synergistic effect with other cytokines on β cell toxicity and autoimmune progression. Given the complex and dynamic crosstalk between immune cells and β cells in T1D setting, blockade of lymphotoxin signaling applied to the existing therapies could be an efficient approach to delay or even reverse the established T1D.

Rheumatoid arthritis and the risk of major cardiometabolic diseases: a Mendelian randomization study

Objective Rheumatoid arthritis (RA) is suggested to be implicated in the development of cardiometabolic diseases. We conducted a Mendelian randomization (MR) study to assess potential causality for associations of RA with the risk of cardiometabolic diseases, including type 2 diabetes (T2D), coronary artery disease (CAD), and ischaemic stroke. Method Seventy independent single-nucleotide polymorphisms (SNPs) associated with RA were identified as instrumental variables from a genome-wide association study (GWAS) of 58 284 European subjects. Summary-level data for the associations of the 70 genetic variants with T2D, CAD, and ischaemic stroke were taken from three GWASs with a total of 1 529 131 participants. Inverse-variance weighted (IVW) MR was used in the main analyses. Results The main IVW MR analysis showed that genetically determined RA was associated with higher risks of T2D [odds ratio (OR): 1.04, 95% confidence interval (CI) 1.02–1.05; p < 0.001] and CAD (OR: 1.02, 95% CI 1.00–1.03; p = 0.012), but not ischaemic stroke (OR: 1.00, 95% CI 0.99–1.02; p = 0.961). Sensitivity analyses with multiple MR methods confirmed these associations. MR-Egger regression showed no evidence of pleiotropy in the association between genetically determined RA and the risk of T2D, CAD, and ischaemic stroke. Leave-one-out sensitivity analysis showed that the association between genetically determined RA and the risk of T2D, CAD, and ischaemic stroke was not driven by any individual SNP. Conclusion Genetically determined RA was associated with increased risks of T2D and CAD, suggesting that RA plays a crucial role in the pathogenesis of T2D and CAD.

Identification of Type 2 Diabetes Biomarkers From Mixed Single-Cell Sequencing Data With Feature Selection Methods.

Diabetes is the most common disease and a major threat to human health. Type 2 diabetes (T2D) makes up about 90% of all cases. With the development of high-throughput sequencing technologies, more and more fundamental pathogenesis of T2D at genetic and transcriptomic levels has been revealed. The recent single-cell sequencing can further reveal the cellular heterogenicity of complex diseases in an unprecedented way. With the expectation on the molecular essence of T2D across multiple cell types, we investigated the expression profiling of more than 1,600 single cells (949 cells from T2D patients and 651 cells from normal controls) and identified the differential expression profiling and characteristics at the transcriptomics level that can distinguish such two groups of cells at the single-cell level. The expression profile was analyzed by several machine learning algorithms, including Monte Carlo feature selection, support vector machine, and repeated incremental pruning to produce error reduction (RIPPER). On one hand, some T2D-associated genes (MTND4P24, MTND2P28, and LOC100128906) were discovered. On the other hand, we revealed novel potential pathogenic mechanisms in a rule manner. They are induced by newly recognized genes and neglected by traditional bulk sequencing techniques. Particularly, the newly identified T2D genes were shown to follow specific quantitative rules with diabetes prediction potentials, and such rules further indicated several potential functional crosstalks involved in T2D.

1024-P: Identification of Sex-Specific Cytokine and Viral Infection Profiles in Type 1 Diabetes Patients

Type 1 Diabetes (T1D) is an autoimmune disease caused by the destruction of beta cells. Because both viral infections and cytokines are suggested to play a role in T1D pathogenesis, we analyzed the viral infection and cytokine profiles of T1D patients compared to age and sex-matched healthy controls. The median age in years of T1D patients was 16.9 ± 1.14 (mean ± SEM) and 17.88 ± 0.78 for the healthy subjects. The disease duration in years was 8 ± 1.1 (n=25, 13 females, 12 males) . We first assessed the viral infection history using a PepSeq-based highly multiplexed serological assay. This assay covers the full proteomes of human viruses and determines serum immunoglobulin-G (IgG) reactivity to 30mer viral peptides. We showed that enterovirus (EV) seropositivity were distinct between the two groups, with more EV-C and EV-D positives in the T1D samples and more EV-A and EV-B positives in the controls. The trends for the viruses showing higher seropositivity were primarily driven by the female patients. To determine the cytokine profiles, we measured the serum levels of 48 cytokines, chemokines and growth factors. Interestingly, we only observed significant sex-specific differences. For example, anti-inflammatory cytokines interleukin-4 (IL-4) , IL-13, IL-22, and pro-inflammatory cytokines IL-17E and tumor necrosis factor-β were significantly lower in female patients as compared to female controls. Male patients had increased levels of epidermal growth factor and platelet-derived growth factor compared to healthy males. IL-22 was unique, unlike the decrease in female patients, it increased in the male patients compared to healthy males. Altogether, we identified sex-dependent alterations in the cytokine profiles and observed a difference in EV exposure profiles between T1D patients and healthy subjects. Determining sex-specific cytokine profiles and the potential role of viral infections in T1D pathogenesis will help us to gain deeper insight into the pathogenesis of the disease. Disclosure K.Girdhar: n/a. A.Pina: None. J.Momirov: None. M.A.Atkinson: None. J.Ladner: None. E.Altindis: None. Funding NIH NIDDK 1K01DK117967-G. Harold &amp; Leila Y. Mathers Foundation grants to EA

184-OR: Antigen-Presenting Cells Can Generate Hybrid Peptides Identified in Type 1 Diabetes

Type 1 Diabetes (T1D) is an autoimmune disease characterized by selective loss of pancreatic β-cells. Aberrant reactivity to insulin and insulin precursor peptides has long been considered important in the pathogenesis of T1D. Recently, T cells recognizing hybrid insulin peptides (HIPs) have been described, first in a rodent model and later in human T1D. A HIP is a CD4 T-cell epitope that is formed by the post-translational fusion of two peptide fragments with at least one of the peptide fragments derived from insulin or a precursor. HIP formation can occur intra- or intermolecularly. The role of these HIPs in the pathogenesis of T1D remains unclear. Others have proposed that HIPs are formed in β-cells during crinophagy of secretory granules. As ultrastructural studies have demonstrated that β-cells can transfer secretory vesicles to local antigen presenting cells (APCs) , we hypothesized that APCs could similarly generate HIPs via protease mediated transpeptidation. To test this, we manufactured peptide-containing nanocarriers mimicking β-cell secretory vesicles to transfer selected peptides to APCs in both mouse and human in vitro systems utilizing donor APCs and CD4 TCR transgenic T cells or a CD4 transductant reporter cells respectively. Here, we demonstrate the subsets of APCs which are capable of intramolecular and intermolecular HIP formation. We further demonstrate that this formation can be blocked by proteosome inhibition. Our study identifies a novel mechanism for the generation of HIPs recognized in T1D. Disclosure S.A.Khokhar: None. M.Liu: None. J.L.Gaglia: Advisory Panel; Dompé, Regeneron Pharmaceuticals Inc., Consultant; Vertex Pharmaceuticals Incorporated, Research Support; Avotres Inc., Dompé, Janssen Research &amp; Development, LLC, Provention Bio, Inc., Stock/Shareholder; Vertex Pharmaceuticals Incorporated. Funding National Institutes of Health 5P30DK036836JDRF 5-ECR-2016-186-A-N

1443-P: Real-Time In Vivo Analysis of Beta-Cell Autophagy in Autoimmune Diabetes

Type 1 Diabetes (T1D) is an autoimmune disease caused by a combination of genetic and environmental factors. The onset of disease is associated with autoimmune attack against pancreatic beta-cells leading to a reduction of their number. While a role for the beta-cell in these events is widely hypothesized, a complete understanding of disease pathogenesis is still lacking. Our group recently found that beta-cell autophagy is defective in the context of human T1D as well as in the non-obese diabetic (NOD) mouse model of autoimmune diabetes. Importantly, our data suggested that defective autophagy is present prior to the onset of diabetes but stopped short of definitively demonstrating pre-existing defects. Therefore, here we evaluated autophagic flux in the pancreatic beta-cells of live mice using a fluorescent biosensor coupled to intravital microscopy. A custom beta-cell-selective autophagy biosensor (AAV8-INS-mCherry-EGFP-LC3B) was intraperitoneally (IP) injected into 7-week-old mice of three strains: wild type C57Bl/6J, NOD and NOD scid gamma (NSG) mice. Three weeks after biosensor injections, mice were placed under inhaled isoflurane anesthesia, then externalized pancreata were imaged using a LEICA SP8 DIVE two-photon microscope mounted with a 40x/1.1NA water objective. To evaluate autophagic flux, we assessed fluorescent signal over time in response to IP infusion of either saline or chloroquine, an autophagy inhibitor. Autophagic flux was assessed by quantifying the rate of change of the ph-sensitive GFP and the ph-insensitive RFP, as well as signal colocalization. In wild type mice, we observed clear evidence of autophagic flux over time that was altered in the presence of chloroquine. However, in contrast, in pre-diabetic NOD mice, islet autophagic flux did not respond effectively to chloroquine treatment. Collectively, these data support the conclusion that autophagy defects precede hyperglycemia and suggest a potential role for these defects in beta cell demise during T1D pathogenesis. Disclosure O.Melnyk: None. C.Muralidharan: None. M.M.Martinez irizarry: None. J.Crowder: None. A.K.Linnemann: Consultant; Janssen Research &amp; Development, LLC. Funding National Institutes of Health (R01DK124380) . Startup funds to AKL from the Herman B Wells Center for Pediatric Research at Indiana University School of Medicine

187-OR: Declines in ß-Cell Glucose Responsiveness Correlate with Loss of Glucose Metabolism during T1D Pathogenesis

Features of type 1 diabetes (T1D) include loss of first-phase insulin secretion in response to glucose, declining c-peptide, and glucose intolerance; indicating β cell dysfunction. Here, we investigate the mechanisms of this dysfunction with the hypothesis that immune dysregulation during the early stages of T1D development impacts β cell dysfunction in pathways affecting glucose metabolism. The live pancreas tissue slice (LPTS) model is ideal for the study of T1D pathogenesis due to its preservation of the pancreatic environment. LPTS were generated from organ donors without diabetes or autoantibodies (ND, n=9) , donors positive for one or more autoantibodies without a diagnosis of T1D (AAb+, n=6) , and donors with T1D (T1D, n=4) . Imaging studies were conducted to assess the impact of T cell infiltration on β cell function through Ca2+ imaging and slice perifusion. Islets from ND and AAb+ donors had no insulitis and exhibited Ca2+ responses to both high glucose (HG) and potassium chloride (KCl) . A majority of β cell+ islets in tissue from donors with T1D had infiltrating T cells with several having insulitis. Islet HG response from donors with T1D was heterogenous (∼50% failed to respond) while all T1D islets exhibited responses to KCl. Insulin secretion was significantly higher in LPTS from ND donors than in donors with T1D (p=0.0079) . To determine the basis for this loss of function, we assessed transcriptomics of islets within these cohorts. When comparing gene expression levels in islets from ND versus T1D, significant differences were observed in genes involved in glycolysis (GAPDH, p=3.27x10-21) , the citric acid cycle components (OGDH, p=1.88x10-18) , and the electric transport chain (F1FoATP synthase, p=2.69x10-13) . The decreased expression of glucose metabolism genes during T1D development along with the loss of β cell function in LPTS demonstrates β cell dysfunction before their demise and may be a contributory mechanism towards the pathogenesis of disease. Disclosure M.Huber: None. M.Slak rupnik: None. D.M.Drotar: None. H.Hiller: None. M.Beery: None. I.Kusmartseva: None. M.A.Atkinson: None. E.Phelps: Research Support; Immunocore, Ltd. C.E.Mathews: None. Funding National Institutes of Health (5T32DK108736-03) National Institutes of Health (PO1 AI42288)

1260-P: Gut Microbiome and Metabolic Activity in Type 1 Diabetes—An Analysis Based on the Presence of GADA

Background: Type 1 diabetes (T1D) progression is affected by the level of circulating glutamic acid decarboxylase antibody (GADA) , a main manifestation of islet autoimmunity. The gut microbiome and serum metabolites may contribute to islet autoimmunity in patients with T1D. Methods: We used radiobinding assay to measure GADA titers and identify the GADA+ ones (n=49) in 1T1D patients. The gut microbiome was assessed by 16S rRNA gene sequencing, and the serum metabolites were analysed with GC/MS. Results: T1D patients with and without GADA exhibited compositional and functional changes in the gut microbiome. Profiles in patients with GADA were distinct, with a significant increase in the abundances of Alistipes, Ruminococcus, Prevotella, Dialister, and marked depletion of Bacteroides, Bifidobacterium, Roseburia. For the untargeted serum metabolites, compared with those of GADA-, there were 54 significantly different metabolites with tryptophan metabolism: phenylalanine, and tyrosine and tryptophan biosynthesis decreased in patients with GADA. In addition, patients with GADA had elevated concentrations of Indole-3-acetic-acid, a marker of intestinal inflammation and epithelial damage. Co-occurrence network analysis revealed that gut microbiome disturbances affected tryptophan metabolism, suggesting that disturbed gut microbiome may mediate T1D immunotypes. Tryptophan metabolism may mediate inflammation in the pathogenesis and pathophysiology of T1D. Conclusion: These findings suggest that metabolites produced by the patients with GADA gut microbiota could cause damage to intestinal and systemic homeostasis and could be targeted for preventing the development of T1D. Disclosure T.Yue: None. X.Zheng: None. Z.Liu: None. Y.Ding: None. J.W.Wei: None. W.Xu: None. J.Weng: None. S.Luo: None. Funding the National Key r&amp;D Program (2017YFC1309600) the Anhui Provincial Natural science foundation (006212943003)

The signal regulatory protein gamma (SIRPγ) signaling constrains naïve CD8+ T cell activation with T1D risk associated polymorphisms leading to augmented T cell activation

Abstract Genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs; rs2281808 and rs6043409) in Signal Regulatory Protein Gamma (SIRPG) with increased susceptibility for type 1 diabetes (T1D). SIRPγ is highly expressed on both CD4+/CD8+ T cells, however, its influence on T cell activation state is insufficiently characterized. We hypothesize that SIRPγ restrains T cell activation and T1D-associated risk variants in SIRPγ influence interactions with its binding partner CD47 to augment CD8+ T cell activation leading to a cytotoxic phenotype. Flow cytometric analysis of PBMC identified SIRPγ/CD47 to be highly expressed on CD4+/CD8+ T cells, with a sequential decline to central memory (TCM), effector memory (TEM), and terminal effector memory cell expressing CD45RA (TEMRA). To test the impact of SIRPγ expression, we generated SIRPG and CD47 knockout (KO) of primary human CD8+ T cells by CRISPR-Cas9 gene editing. Following in vitro activation with anti-CD3/CD28, SIRPG/CD47 KO CD8+ T cells exhibited significantly higher surface activation markers (CD25/CD69) and lower co-inhibitory receptors (CTLA-4/PD-1) compared to controls. Moreover, naïve SIRPγ KO CD8+ T cells differentiated at a higher rate into TEMRA cells. In terms of effector function, SIRPG/CD47 KO CD8+ T cell cultures produced higher levels of the effector molecules TNFα, perforin, and granzyme B and exhibited significantly more cytotoxic killing potential when co-cultured with a targeted pancreatic cell line (βLox5). Overall, this study suggests the SIRPγ:CD47 signaling pathway serves as an immune checkpoint for T cell activation and differentiation of T cells, with the potential for therapeutic targeting during T1D pathogenesis.

A Contemporary Insight of Metabolomics Approach for Type 1 Diabetes: Potential for Novel Diagnostic Targets.

High-throughput omics has been widely applied in metabolic disease, type 1 diabetes (T1D) was one of the most typical diseases. Effective prevention and early diagnosis are very important because of infancy and persistent characteristics of T1D. The occurrence and development of T1D is a chronic and continuous process, in which the production of autoantibodies (ie serum transformation) occupies the central position. Metabolomics can evaluate the metabolic characteristics of serum before seroconversion, the changes with age and T1D complications. And the addition of natural drug metabolomics is more conducive to the systematic and comprehensive diagnosis and treatment of T1D. This paper reviewed the metabolic changes and main pathogenesis from pre-diagnosis to treatment in T1D. The metabolic spectrum of significant abnormal energy and glucose-related metabolic pathway, down-regulation of lipid metabolism and up-regulation of some antioxidant pathways has appeared before seroconversion, indicating that the body has been in the dual state of disease progression and disease resistance before T1D onset. Some metabolites (such as methionine) are closely related to age, and the types of autoantibodies produced are age-specific. Some metabolites may jointly predict DN with eGFR, and metabolomics can further contribute to the pathogenesis based on the correlation between DN and DR. Many natural drug components have been proved to act on abnormal metabolic pathways of T1D and have a positive impact on some metabolic levels, which is very important for further finding therapeutic targets and developing new drugs with small side effects. Metabolomics can provide auxiliary value for the diagnosis of T1D and provide a new direction to reveal the pathogenesis of T1D and find new therapeutic targets. The development of T1D metabolomics shows that high-throughput research methods are expected to be introduced into clinical practice.

Magnesium deficiency in type 2 diabetes mellitus andits effect on blood glucose control and diabetes complications

Background. Diabetes has become more often in all over the world, magnesium is an essential element of the body and has lots of vital functions. There has been a trend to investigate magnesium’s effect on type2 diabetes pathogenesis and its complications. Still, more data is needed to reveal magnesium and T2 diabetes mellitus (DM) association, therefore we aimed to investigate how common magnesium deficiency in Turkish T2DM patients, and its effect on diabetes control and diabetes complications. Materials and methods. 296 patients with type 2 DM and 96 healthy controls aged between 18–65 years were enrolled in the study. After exclusion criteria, T2DM patients were divided into 2 groups according to magnesium deficiency, metabolic and physical properties of the groups were compared. Also, hypertension, metabolic syndrome, coronary artery disease, and microalbuminuria were also compared according to magnesium deficiency. Results. Magnesium deficiency was found 35.5% (86/242) in patients with type 2 DM, 4.1% (4/96) in the control group. Magnesium deficiency was more in female patients (64/86, 74.4%), male patients had more normal magnesium levels 89/166, 53.6%) (p&lt;0.01). Hypomagnеsemia patients with T2 DM didn’t show difference in HbA1c (9.0±1.9% vs 8.8±1.6%, p=0.35), and fasting blood glucose levels (197.24±87.25 vs 177.85±57.22 mg/dl, p=0.14). Hypomagnеsemia patients with T2DM had significantly higher hyperlipidemia levels (48.8% (42/86) vs 41.0% (64/156), p=0.04). Metabolic syndrome (89.0% (73/82) vs 83.1% (123/148), p=0.22) and coronary artery syndrome (39.5% (34/86) vs 35.9% (56/156), p=0.85) didn’t differ between groups. Hypertension (81.4% (70/86) vs 67.9 (60/156), p=0.04) and microalbuminuria (66.7% (38/57) vs 43.7 (58/119), p=0.03) were significantly higher in the hypomagnеsemia T2DM group. Conclusions. Magnesium deficiency is not rare in T2DM, however, this deficiency didn’t impact blood glucose control at a significant level in current study, on the other hand, hypertension, microalbuminuria, and hyperlipidemia components of diabetes have been shown to increase with magnesium deficiency.

Viral infection‐related gene upregulation in monocytes in children with signs of β‐cell autoimmunity

ObjectiveThe pathogenesis of type 1 diabetes (T1D) is associated with genetic predisposition and immunological changes during presymptomatic disease. Differences in immune cell subset numbers and phenotypes between T1D patients and healthy controls have been described; however, the role and function of these changes in the pathogenesis is still unclear. Here we aimed to analyze the transcriptomic landscapes of peripheral blood mononuclear cells (PBMCs) during presymptomatic disease.MethodsTranscriptomic differences in PBMCs were compared between cases positive for islet autoantibodies and autoantibody negative controls (9 case–control pairs) and further in monocytes and lymphocytes separately in autoantibody positive subjects and control subjects (25 case–control pairs).ResultsNo significant differential expression was found in either data set. However, when gene set enrichment analysis was performed, the gene sets “defence response to virus” (FDR <0.001, ranking 2), “response to virus” (FDR <0.001, ranking 3) and “response to type I interferon” (FDR = 0.002, ranking 12) were enriched in the upregulated genes among PBMCs in cases. Upon further analysis, this was also seen in monocytes in cases (FDR = 0.01, ranking 2; FDR = 0.04, ranking 3 and FDR = 0.02, ranking 1, respectively) but not in lymphocytes.ConclusionGene set enrichment analysis of children with T1D‐associated autoimmunity revealed changes in pathways relevant for virus infection in PBMCs, particularly in monocytes. Virus infections have been repeatedly implicated in the pathogenesis of T1D. These results support the viral hypothesis by suggesting altered immune activation of viral immune pathways in monocytes during diabetes.

CircRNA hsa_circ_0071336 is associated with type 2 diabetes through targeting the miR-93-5p/GLUT4 axis.

Glucose transporter 4 (GLUT4) is a dominant regulator of whole-body glucose homeostasis. Accumulating evidence has shown that circular RNAs (circRNAs) play significant roles in the pathogenesis of disease. The aim of the present study was to identify the circRNA that can be used as a novel biomarker for type 2 diabetes (T2D) through regulating GLUT4. Based on previous microarray analysis comparing T2D cases and healthy controls, hsa_circ_0071336, which was predicted to be a regulator of GLUT4 by acting as a competitive endogenous RNAs (ceRNA) to sponge miR-93-5p, was selected for further validation. The clinical significance of circulating hsa_circ_0071336 was investigated in a large independent cohort. The results showed that circulating hsa_circ_0071336 was significantly downregulated in blood in T2D and had a high diagnostic accuracy for discriminating T2D and impaired fasting glucose (IFG) from healthy controls. Low expression of circ_0071336 was an independent predictor of T2D, IFG and insulin resistance. A luciferase reporter assay and western-blot analysis indicated that miR-93-5p was a direct target of hsa_circ_0071336, and miR-93-5p may negatively regulate the expression of GLUT4. The expression levels of hsa_circ_007136 were negatively related to miR-93-5p expression and positively correlated with the mRNA expression of GLUT4 in adipose tissues. In conclusion, hsa_circRNA_0071336 can be considered as a potential novel and stable biomarker for T2D and its early detection. hsa_circ_0071336 regulates the GLUT4 expression by sponging miR-93-5p and maybe involved in the pathogenesis of T2D. These findings may unveil new targets for the prevention, diagnosis and treatment of T2D.

Secretory granule exocytosis and its amplification by cAMP in pancreatic β-cells.

The sequence of events for secreting insulin in response to glucose in pancreatic β-cells is termed "stimulus-secretion coupling". The core of stimulus-secretion coupling is a process which generates electrical activity in response to glucose uptake and causes Ca2+ oscillation for triggering exocytosis of insulin-containing secretory granules. Prior to exocytosis, the secretory granules are mobilized and docked to the plasma membrane and primed for fusion with the plasma membrane. Together with the final fusion with the plasma membrane, these steps are named the exocytosis process of insulin secretion. The steps involved in the exocytosis process are crucial for insulin release from β-cells and considered indispensable for glucose homeostasis. We recently confirmed a signature of defective exocytosis process in human islets and β-cells of obese donors with type 2 diabetes (T2D). Furthermore, cyclic AMP (cAMP) potentiates glucose-stimulated insulin secretion through mechanisms including accelerating the exocytosis process. In this mini-review, we aimed to organize essential knowledge of the secretory granule exocytosis and its amplification by cAMP. Then, we suggest the fatty acid translocase CD36 as a predisposition in β-cells for causing defective exocytosis, which is considered a pathogenesis of T2D in relation to obesity. Finally, we propose potential therapeutics of the defective exocytosis based on a CD36-neutralizing antibody and on Apolipoprotein A-I (ApoA-I), for improving β-cell function in T2D.

Oxidative RNA Damage in the Pathogenesis and Treatment of Type 2 Diabetes.

Excessive production of free radicals can induce cellular damage, which is associated with many diseases. RNA is more susceptible to oxidative damage than DNA due to its single-stranded structure, and lack of protective proteins. Yet, oxidative damage to RNAs received little attention. Accumulating evidence reveals that oxidized RNAs may be dysfunctional and play fundamental role in the occurrence and development of type 2 diabetes (T2D) and its complications. Oxidized guanine nucleoside, 8-oxo-7, 8-dihydroguanine (8-oxoGuo) is a biomarker of RNA oxidation that could be associated with prognosis in patients with T2D. Nowadays, some clinical trials used antioxidants for the treatment of T2D, though the pharmacological effects remained unclear. In this review, we overview the cellular handling mechanisms and the consequences of the oxidative RNA damage for the better understanding of pathogenesis of T2D and may provide new insights to better therapeutic strategy.