The pathogenesis and natural history of type 1 diabetes

The Role of T Cell Receptor Signaling in the Development of Type 1 Diabetes

T cell receptor (TCR) signaling influences multiple aspects of CD4⁺ and CD8⁺ T cell immunobiology including thymic development, peripheral homeostasis, effector subset differentiation/function, and memory formation. Additional T cell signaling cues triggered by co-stimulatory molecules and cytokines also affect TCR signaling duration, as well as accessory pathways that further shape a T cell response. Type 1 diabetes (T1D) is a T cell-driven autoimmune disease targeting the insulin producing β cells in the pancreas. Evidence indicates that dysregulated TCR signaling events in T1D impact the efficacy of central and peripheral tolerance-inducing mechanisms. In this review, we will discuss how the strength and nature of TCR signaling events influence the development of self-reactive T cells and drive the progression of T1D through effects on T cell gene expression, lineage commitment, and maintenance of pathogenic anti-self T cell effector function.

Negative regulation of FOXP3 expression by c-Rel O-GlcNAcylation

O-GlcNAcylation is a reversible post-translational protein modification that regulates fundamental cellular processes including immune responses and autoimmunity. Previously, we showed that hyperglycemia increases O-GlcNAcylation of the transcription factor, nuclear factor kappaB c-Rel at serine residue 350 and enhances the transcription of the c-Rel-dependent proautoimmune cytokines interleukin-2, interferon gamma and granulocyte macrophage colony stimulating factor in T cells. c-Rel also plays a critical role in the transcriptional regulation of forkhead box P3 (FOXP3)-the master transcription factor that governs development and function of Treg cells. Here we show that the regulatory effect of c-Rel O-GlcNAcylation is gene-dependent, and in contrast to its role in enhancing the expression of proautoimmune cytokines, it suppresses the expression of FOXP3. Hyperglycemia-induced O-GlcNAcylation-dependent suppression of FOXP3 expression was found in vivo in two mouse models of autoimmune diabetes; streptozotocin-induced diabetes and spontaneous diabetes in nonobese diabetic mice. Mechanistically, we show that both hyperglycemia-induced and chemically enhanced cellular O-GlcNAcylation decreases c-Rel binding at the FOXP3 promoter and negatively regulates FOXP3 expression. Mutation of the O-GlcNAcylation site in c-Rel, (serine 350 to alanine), augments T cell receptor-induced FOXP3 expression and resists the O-GlcNAcylation-dependent repression of FOXP3 expression. This study reveals c-Rel S350 O-GlcNAcylation as a novel molecular mechanism inversely regulating immunosuppressive FOXP3 expression and proautoimmune gene expression in autoimmune diabetes with potential therapeutic implications.

Stress Hyperglycemia in Children and Adolescents as a Prognostic Indicator for the Development of Type 1 Diabetes Mellitus

Hyperglycemia is a common manifestation in the course of severe disease and is the result of acute metabolic and hormonal changes associated with various factors such as trauma, stress, surgery, or infection. Numerous studies demonstrate the association of adverse clinical events with stress hyperglycemia. This article briefly describes the pathophysiological mechanisms which lead to hyperglycemia under stressful circumstances particularly in the pediatric and adolescent population. The importance of prevention of hyperglycemia, especially for children, is emphasized and the existing models for the prediction of diabetes are presented. The available studies on the association between stress hyperglycemia and progress to type 1 diabetes mellitus are presented, implying a possible role for stress hyperglycemia as part of a broader prognostic model for the prediction and prevention of overt disease in susceptible patients.

Comprehensive Analyses of Type 1 Diabetes Ketosis- or Ketoacidosis-Related Genes in Activated CD56+CD16+ NK Cells

OBJECTIVES

Alterations in natural killer (NK) cells activity cause damage to pancreatic islets in type 1 diabetes mellitus (T1DM). The aim of this study is to identify T1DM ketosis- or ketoacidosis-related genes in activated CD56⁺CD16⁺ NK cells.

METHODS

Microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using the GEO2R tool. Enrichment analyses were performed using Metascape online database and GSEA software. Cell-specific gene co-expression network was built using NetworkAnalyst tools. Cytoscape software was used to identify hub genes and construct co-expressed networks. Target miRNAs were predicted based on the DIANA-micro T, miRDB, and miRWalk online databases.

RESULTS

A total of 70 DEGs were identified between T1DM patients recovered from ketosis or ketoacidosis and healthy control blood samples in GSE44314. Among the DEGs, 10 hub genes were screened out. The mature NK cell-specific gene co-expression network for DEGs in T1DM was built using NetworkAnalyst tools. DEGs between activated CD56⁺CD16⁺ NK cells and CD56^brightCD16^- NK cells were identified from GSE1511. After intersection, 13 overlapping genes between GSE44314 and GSE1511 microarray datasets were screened out, in which 7 hub genes were identified. Additionally, 59 target miRNAs were predicted according to the 7 hub genes. After validating with the exosome miRNA expression profile dataset of GSE97123, seven differentially expressed miRNAs (DEmiRNAs) in plasma-derived exosome were selected. Finally, a mRNA-miRNA network was constructed, which was involved in the T1DM ketosis or ketoacidosis process.

CONCLUSION

This work identified seven hub genes in activated CD56⁺CD16⁺ NK cells and seven miRNAs in plasma-derived exosome as potential predictors of T1DM ketoacidosis, which provided a novel insight for the pathogenesis at the transcriptome level.

Epigenetic Effects of Gut Metabolites: Exploring the Path of Dietary Prevention of Type 1 Diabetes

Type 1 diabetes (T1D) has increased over the past half century and has now become the second most frequent autoimmune disease in childhood and one of major public health concern worldwide. Evidence suggests that modern lifestyles and rapid environmental changes are driving factors that underlie this increase. The integration of these two factors brings about changes in food intake. This, in turn, alters epigenetic regulations of the genome and intestinal microbiota composition, which may ultimately play a role in pathogenesis of T1D. Recent evidence shows that dysbiosis of the gut microbiota is closely associated with T1D and that a dietary intervention can influence epigenetic changes associated with this disease and may modify gene expression patterns through epigenetic mechanisms. In this review focus on how a diet can shape the gut microbiome, its effect on the epigenome in T1D, and the future of T1D management by microbiome therapy.

Autoimmune Endocrinopathies: An Emerging Complication of Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (CPIs) reverse immune suppression that is thought to allow malignant growth. Despite remarkable efficacy in a subset of cancers, their use is accompanied by immune-related adverse events, including endocrinopathies such as hypophysitis, thyroid dysfunction, diabetes, and adrenalitis. These conditions are heterogenous, with differing incidence across CPI types, but are unified by the acuity and extremity of tissue-specific organ failure. Their occurrence may be associated with beneficial tumor control. Further understanding of the risk factors and mechanisms of these endocrine immunotoxicities can help optimize CPI use as well as improve understanding of spontaneous autoimmune diseases.

Patients’ and healthcare professionals’ perspectives towards technology-assisted diabetes self-management education. A qualitative systematic review

Introduction

Diabetes self-management education is a key aspect in the long-term management of type 2 diabetes. The patient and healthcare professional (HCP) perspective on the use of technology-assisted DSME has yet to be studied. Hence, the objective of this study was to better understand the factors that facilitate or hinder the adoptions of such education by adults with type 2 diabetes and their HCPs.

Methods

We systematically searched five databases (Medline, Embase, CINAHL, Web of Science Core Collection, and PsycINFO) until August 2019. The search included qualitative and mixed-method studies that reported the views of patients and HCPs regarding features, uses, and implementations of technology-assisted DSME. Data were synthesized through an inductive thematic analysis.

Results

A total of 13 articles were included, involving 242 patients, ranging from 18 to 81 years and included web-based, mobile application, digital versatile disc (DVD), virtual reality or telehealth interventions. Patients and HCPs had mixed views towards features of the technology-assisted interventions, with patients’ personal qualities and HCPs’ concerns affecting uses of the interventions. Patients generally preferred technologies that were easy to access, use, and apply and that had reliable information. Patients’ ambitions motivated them, and personal attributes such as poor competence with technology, poor literacy, and language barriers acted as barriers. Patients especially liked the peer support that they received but did not like it when there was no regulation of advice on these platforms. HCPs believed that while the interventions were useful to patients, they faced difficulties with integration into their clinical workflows.

Conclusion

This review explored the features of technology-assisted diabetes self-management education interventions that enhanced positive patient engagements and the negative aspects of both the platforms and the target groups. Technical support and training will be effective in managing these concerns and ensuring meaningful use of these platforms.

Procyanidin B2 Improves Oocyte Maturation and Subsequent Development in Type 1 Diabetic Mice by Promoting Mitochondrial Function

Type 1 diabetes (T1D) results in decreased oocyte quality and compromised early embryonic development. Procyanidin B2 (PB2) is a natural compound extracted from grape seeds and has strong antioxidant activity in vivo. This study evaluated the effect of PB2 on oocyte maturation in diabetic mice. Diabetic mice were induced by streptozotocin (STZ) injection. PB2 was supplemented in the in vitro maturation medium, and the ratio of germinal vesicle breakdown (GVBD) and polar body extrusion (PBE), reactive oxygen species (ROS) levels, mitochondrial function, developmental ability, as well as crotonylation at H4K5 were determined in oocytes. PB2 can promote the extrusion of PBE (88.34% vs. 75.02%, P < 0.05); reduce the generation of ROS (1.12 vs. 1.96, P < 0.05); and improve the level of mitochondrial membrane potential (0.87 vs. 0.79 Δφm, P < 0.05), ATP level (1.31 vs. 0.71 pmol, P < 0.05), and mitochondria temperature (618.25 vs. 697.39 pixels, P < 0.05). The addition of PB2 also improved the level of oocyte crotonylation at H4K5 (crH4K5) (47.26 vs. 59.68 pixels, P < 0.05) and increased the blastocyst rate (61.51% vs. 36.07%, P < 0.05) after parthenogenetic activation. Our results are the first to reveal a role for PB2 in promoting the viability of oocytes by regulating the mitochondrial function. Moreover, we uncover that PB2 can improve the level of crH4K5, which provides a new strategy to combat the decline in oocyte quality of diabetic.

Emerging roles of non-coding RNAs in the pathogenesis of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1D) is a lifelong autoimmune disorder that is increasingly prevalent in populations worldwide. As well as affecting adults, T1D is one of the most prevalent chronic childhood disorders. Several lines of evidence point to dysregulation of both cellular and humoral immune responses in this disorder. Several genetic loci have been associated with risk of T1D, implying the presence of a complex multifactorial pattern of inheritance for this disorder. Moreover, recent studies have reported dysregulation of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in animal models of T1D or clinical samples. Several immune-related molecules and pathways such as NF-κB, PI3K/Akt/FOXO, JAK, MAPK, mTOR and STAT pathways are regulated by non-coding RNAs in the context of T1D. Improved understanding of the role of lncRNAs and miRNAs in the pathogenesis of T1D would facilitate design of preventive therapeutic modalities. In the current review, we summarize the results of animal and human studies that report dysregulation of these transcripts and their function in T1D.

Designing a bioelectronic treatment for Type 1 diabetes: targeted parasympathetic modulation of insulin secretion

The pancreas is a visceral organ with exocrine functions for digestion and endocrine functions for maintenance of blood glucose homeostasis. In pancreatic diseases such as Type 1 diabetes, islets of the endocrine pancreas become dysfunctional and normal regulation of blood glucose concentration ceases. In healthy individuals, parasympathetic signaling to islets via the vagus nerve, triggers release of insulin from pancreatic β-cells and glucagon from α-cells. Using electrical stimulation to augment parasympathetic signaling may provide a way to control pancreatic endocrine functions and ultimately control blood glucose. Historical data suggest that cervical vagus nerve stimulation recruits many visceral organ systems. Simultaneous modulation of liver and digestive function along with pancreatic function provides differential signals that work to both raise and lower blood glucose. Targeted pancreatic vagus nerve stimulation may provide a solution to minimizing off-target effects through careful electrode placement just prior to pancreatic insertion.

Targeting Glycoproteins as a therapeutic strategy for diabetes mellitus and its complications

OBJECTIVES

Glycoproteins are organic compounds formed from proteins and carbohydrates, which are found in many parts of the living systems including the cell membranes. Furthermore, impaired metabolism of glycoprotein components plays the main role in the pathogenesis of diabetes mellitus. The aim of this study is to investigate the influence of glycoprotein levels in the treatment of diabetes mellitus.

METHODS

All relevant papers in the English language were compiled by searching electronic databases, including Scopus, PubMed and Cochrane library. The keywords of glycoprotein, diabetes mellitus, glycan, glycosylation, and inhibitor were searched until January 2019.

RESULTS

Glycoproteins are pivotal elements in the regulation of cell proliferation, growth, maturation and signaling pathways. Moreover, they are involved in drug binding, drug transportation, efflux of chemicals and stability of therapeutic proteins. These functions, structure, composition, linkages, biosynthesis, significance and biological effects are discussed as related to their use as a therapeutic strategy for the treatment of diabetes mellitus and its complications.

CONCLUSIONS

The findings revealed several chemical and natural compounds have significant beneficial effects on glycoprotein metabolism. The comprehension of glycoprotein structure and functions are very essential and inevitable to enhance the knowledge of glycoengineering for glycoprotein-based therapeutics as may be required for the treatment of diabetes mellitus and its associated complications. Graphical abstract.

Neuroprotective and memory-enhancing effects of methanolic leaf extract of Peristrophe bicalyculata in rat model of type 2 diabetes mellitus

This study investigated the effect of methanolic leaf extract of Peristrophe Bicalyculata (MEPb) on type 2 diabetes mellitus (T2DM) associated cognitive decline in Wistar rats. 36 male rats weighing 130-200 g were assigned into 6 groups (n = 6) as follows: normal control, diabetic control, pioglitazone-treated diabetic and three MEPb-treated diabetic groups, type 2 diabetes mellitus was induced with low dose streptozocin (STZ) injection following 3 weeks of high fat diet (HFD) intake. Thirty days after diabetes induction, rats exhibited marked and persistent hyperglycemia, animals were treated with MEPb (50, 100 and 200 mg/kg) and pioglitazone (10 mg/kg) as standard. Morris water maze (MWM) test and Novel object recognition test (NORT) were used to assess learning and memory. Blood glucose level, oxidative stress makers, pro-inflammatory marker and acetylcholinestarase activities were analysed. Both MEPb and pioglitazone significantly (P < 0.05) reduced escape latency in treated animals compared to the diabetic control group in the MWM test. Methanolic leaf extract of Peristrophe bicalyculata and pioglitazone also significantly (P < 0.05) increased discrimination index in treated animals compared to the diabetic control group in the novel object recognition test. Serum, brain and liver MDA levels were significantly (P < 0.05) decreased in MEPb and pioglitazone treated rats compared to diabetic control. Serum and liver GSH as well as CAT levels were significantly (P < 0.05) increased while brain GSH and CAT levels shows apparent increase in MEPb and pioglitazone treated rats compared with diabetic control. Treatment with MEPb caused a significant (P < 0.05) decrease in brain nitrite level, interleukin 6 and acetylcholinesterase activity compared to diabetic control group. We conclude that Methanolic leaf extract of Peristrophe bicalyculata enhanced antioxidant capacity and prevented neuroinflammation, consequently improving brain neuronal cholinergic function in experimental animals.

Tracking of an Oral Salmonella-Based Vaccine for Type 1 Diabetes in Non-obese Diabetic Mice

Type 1 diabetes (T1D) arises secondary to immune-driven destruction of pancreatic β-cells and manifests as insulin-deficient hyperglycemia. We showed that oral vaccination with live attenuated Salmonella, which simultaneously delivers autoantigens and a TGFβ expression vector to immune cells in the gut mucosa, provides protection against the progression of T1D in non-obese diabetic (NOD) mice. In this study we employed the Sleeping Beauty (SB) transposon system that is composed of a transposase and transposon encoding the td-Tomato to express red fluorescent protein (RFP) to permanently mark the cells that take up the Salmonella vaccine. After animal vaccination, the transposon labeled-dendritic cells (DCs) with red fluorescence appeared throughout the secondary lymphoid tissues. Furthermore, Sleeping Beauty containing tgfβ1 gene (SB-tgfβ1) co-expressed TGFβ and RFP. The labeled DCs were detected predominantly in Peyer's patches (PP) and mesenteric lymph nodes (MLN) and expressed CD103 surface marker. CD103+ DCs induced tolerogenic effects and gut homing. TGFβ significantly increased programmed death-ligand-1 (PDL-1 or CD274) expression in the DCs in the MLN and PP of treated mice. Also, TGFβ increased cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) levels in CD4+ cells in MLN and PP. Interestingly, DCs increased in all lymphatic organs of mice vaccinated with oral live Salmonella-based vaccine expressing preproinsulin (PPI), in combination with TGFβ, IL10, and subtherapeutic-doses of anti-CD3 mAb compared with vehicle-treated mice. These DCs are mostly tolerogenic in MLN and PP. Furthermore the DCs obtained from vaccine-treated but not vehicle-treated mice suppressed in vitro T cell proliferation. These data suggest that the MLN and the PP are a central hub for the beneficial anti-diabetic effects of an oral Salmonella-based vaccine prevention of diabetes in rodents.

Beta Cell Dedifferentiation Induced by IRE1α Deletion Prevents Type 1 Diabetes

Immune-mediated destruction of insulin-producing β cells causes type 1 diabetes (T1D). However, how β cells participate in their own destruction during the disease process is poorly understood. Here, we report that modulating the unfolded protein response (UPR) in β cells of non-obese diabetic (NOD) mice by deleting the UPR sensor IRE1α prior to insulitis induced a transient dedifferentiation of β cells, resulting in substantially reduced islet immune cell infiltration and β cell apoptosis. Single-cell and whole-islet transcriptomics analyses of immature β cells revealed remarkably diminished expression of β cell autoantigens and MHC class I components, and upregulation of immune inhibitory markers. IRE1α-deficient mice exhibited significantly fewer cytotoxic CD8⁺ T cells in their pancreata, and adoptive transfer of their total T cells did not induce diabetes in Rag1^-/- mice. Our results indicate that inducing β cell dedifferentiation, prior to insulitis, allows these cells to escape immune-mediated destruction and may be used as a novel preventive strategy for T1D in high-risk individuals.

Pancreatic islets seeded in a novel bioscaffold forms an organoid to rescue insulin production and reverse hyperglycemia in models of type 1 diabetes

Therapeutic approaches to combat type 1 diabetes (T1D) include donor pancreas transplantation, exogenous insulin administration and immunosuppressive therapies. However, these clinical applications are limited due to insufficient tissue compatible donors, side effects of exogenous insulin administration and/or increased onset of opportunistic infections attributable to induced global immunosuppression. An alternative approach to alleviate disease states is to utilize insulin-producing pancreatic islets seeded in a bioscaffold for implantation into diabetic recipients. The present studies now report that a newly developed cationic polymer biomaterial serves as an efficient bioscaffold for delivery of donor syngeneic pancreatic islet cells to reverse hyperglycemia in murine streptozotocin induced- or non-obese diabetic mouse models of T1D. Intraperitoneal implantation of pancreatic islets seeded within the copolymer bioscaffold supports long-term cell viability, response to extracellular signaling cues and ability to produce soluble factors into the microenvironment. Elevated insulin levels were measured in recipient diabetic mice upon implantation of the islet-seeded biomaterial coupled with reduced blood glucose levels, collectively resulting in increased survival and stabilization of metabolic indices. Importantly, the implanted islet-seeded biomaterial assembled into a solid organoid substructure that reorganized the extracellular matrix compartment and recruited endothelial progenitors for neovascularization. This allowed survival of the graft long-term in vivo and access to the blood for monitoring glucose levels. These results highlight the novelty, simplicity and effectiveness of this biomaterial for tissue regeneration and in vivo restoration of organ functions.

Proposing BCG Vaccination for Mycobacterium avium ss. paratuberculosis (MAP) Associated Autoimmune Diseases

Bacille Calmette-Guerin (BCG) vaccination is widely practiced around the world to protect against the mycobacterial infection tuberculosis. BCG is also effective against the pathogenic mycobacteria that cause leprosy and Buruli's ulcer. BCG is part of the standard of care for bladder cancer where, when given as an intravesicular irrigant, BCG acts as an immunomodulating agent and lessens the risk of recurrence. Mycobacterium avium ss. paratuberculosis (MAP) causes a fatal enteritis of ruminant animals and is the putative cause of Crohn's disease of humans. MAP has been associated with an increasingly long list of inflammatory/autoimmune diseases: Crohn's, sarcoidosis, Blau syndrome, Hashimoto's thyroiditis, autoimmune diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis, lupus and Parkinson's disease. Epidemiologic evidence points to BCG providing a "heterologous" protective effect on assorted autoimmune diseases; studies using BCG vaccination for T1D and MS have shown benefit in these diseases. This article proposes that the positive response to BCG in T1D and MS is due to a mitigating action of BCG upon MAP. Other autoimmune diseases, having a concomitant genetic risk for mycobacterial infection as well as cross-reacting antibodies against mycobacterial heat shock protein 65 (HSP65), could reasonably be considered to respond to BCG vaccination. The rare autoimmune disease, relapsing polychondritis, is one such disease and is offered as an example. Recent studies suggesting a protective role for BCG in Alzheimer's disease are also explored. BCG-induced energy shift from oxidative phosphorylation to aerobic glycolysis provides the immunomodulating boost to the immune response and also mitigates mycobacterial infection-this cellular mechanism unifies the impact of BCG on the disparate diseases of this article.

Standard mortality rates and years of life lost for serologically defined adult-onset type 1 and type 2 diabetes - A fifteen year follow-up

AIMS

The Diabetes Incidence in Kronoberg (DIK) study of adult-onset diabetes used serological classification. Standard Mortality Rates (SMR) and Years of Life Lost (YLL) 15 years after adult-onset (18-100 years) of diabetes were compared to the population of Kronoberg.

METHODS

Of 1609/1660 (97%) patients, 112 (7%) had type 1 (T1D) (GADA⁺ and/or ICA⁺, and/or C-peptide < 0.25 nmol/l), and 1497 (93%) had type 2 diabetes (T2D) (antibody^- and C-peptide ≥ 0.25 nmol/l). The National Swedish Mortality Register provided time of death.

RESULTS

For T1D SMR did not differ from the Kronoberg population in any age group. In T2D SMR was 1.20 (1.12-1.29). After 15 years 26% (29/112) T1D and 52% (785/1497) T2D patients had died, p < 0.0001. In T2D SMR was 5.6 (30-39 years), 2 (40-59 years), 1.4 (60-69 years), and thereafter no difference. There were no significant sex differences in mortality, and no YLL to adult-onset T1D, but five YLL to T2D for onset at ages 20-60 years.

CONCLUSIONS

For adult-onset T1D SMR did not differ from the general population, in contrast to previous findings in childhood-onset (< 30 years of age) T1D. The difference in mortality between persons with diabetes and the general population was due to higher mortality in T2D.

Insulin Therapy in Adults with Type 1 Diabetes Mellitus: a Narrative Review

Here, we review insulin management options and strategies in nonpregnant adult patients with type 1 diabetes mellitus (T1DM). Most patients with T1DM should follow a regimen of multiple daily injections of basal/bolus insulin, but those not meeting individual glycemic targets or those with frequent or severe hypoglycemia or pronounced dawn phenomenon should consider continuous subcutaneous insulin infusion. The latter treatment modality could also be an alternative based on patient preferences and availability of reimbursement. Continuous glucose monitoring may improve glycemic control irrespective of treatment regimen. A glycemic target of glycated hemoglobin < 7% (53 mmol/mol) is appropriate for most nonpregnant adults. Basal insulin analogues with a reduced peak profile and an extended duration of action with lower intraindividual variability relative to neutral protamine Hagedorn insulin are preferred. The clinical advantages of basal analogues compared with older basal insulins include reduced injection burden, better efficacy, lower risk of hypoglycemic episodes (especially nocturnal), and reduced weight gain. For prandial glycemic control, any rapid-acting prandial analogue (aspart, glulisine, lispro) is preferred over regular human insulin. Faster-acting insulin aspart is a relatively new option with the advantage of better postprandial glucose coverage. Frequent blood glucose measurements along with patient education on insulin dosing based on carbohydrate counting, premeal blood glucose, and anticipated physical activity is paramount, as is education on the management of blood glucose under different circumstances.Plain Language Summary: Plain language summary is available for this article.

Glycated Plasma Proteins as More Sensitive Markers for Glycemic Control in Type 1 Diabetes

PURPOSE

Glycated hemoglobin (HbA1c) is used clinically for diagnosis and therapeutic management of diabetes. However, HbA1c reflects average blood glucose level over a long period. The aim of this study is to look for short period, more sensitive protein markers that correlate better with glycemic level.

EXPERIMENTAL DESIGN

The glycated proteome of human plasma from type 1 diabetic individuals with good and poor (n = 20 each) glycemic control are analyzed using an online two-dimensional proteomics approach. Selected glycated peptides are further validated for their potential as candidate biomarkers using parallel reaction monitoring.

RESULTS

305 glycated peptides are quantified and 290 are significantly increased in samples with poor glycemic control. 76 of the 88 selected glycated peptides have receiver operating characteristic area under curve (AUC) values greater than 0.8. Six validated glycated peptides with high AUC show high correlation with HbA1c and have higher fold changes between poor and good glycemic control than HbA1c. The parent proteins have half-lives shorter than HbA1c.

CONCLUSIONS AND CLINICAL RELEVANCE

Using an advanced proteomics platform for protein glycation analysis, glycated peptides and proteins are identified that are promising as more sensitive, shorter term indicators of glycemic control in diabetic patients than the commonly used HbA1c.

The Role of β Cell Stress and Neo-Epitopes in the Immunopathology of Type 1 Diabetes

Due to their secretory function, β cells are predisposed to higher levels of endoplasmic reticulum (ER) stress and greater sensitivity to inflammation than other cell types. These stresses elicit changes in β cells that alter their function and immunogenicity, including defective ribosomal initiation, post-translational modifications (PTMs) of endogenous β cell proteins, and alternative splicing. Multiple published reports confirm the presence of not only CD8+ T cells, but also autoreactive CD4+ T cells within pancreatic islets. Although the specificities of T cells that infiltrate human islets are incompletely characterized, they have been confirmed to include neo-epitopes that are formed through stress-related enzymatic modifications of β cell proteins. This article summarizes emerging knowledge about stress-induced changes in β cells and data supporting a role for neo-antigen formation and cross-talk between immune cells and β cells that provokes autoimmune attack - leading to a breakdown in tissue-specific tolerance in subjects who develop type 1 diabetes.

Therapeutic Effects of BCG Vaccination on Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Type 1 diabetes mellitus (T1DM) causes the irreversible destruction of pancreatic beta cells. The Bacillus Calmette-Guerin (BCG) vaccine can modulate the immune response and decelerate disease progression. The aim of this study is to investigate the efficacy of the BCG vaccine for the treatment of T1DM.

OBJECTIVE

Six databases were systematically searched from inception to the end of August 2019. The randomized controlled trials (RCTs) that evaluated glycemic control in response to the BCG vaccine for T1DM were enrolled. The primary outcome was glycated hemoglobin (HbA1c) level, and secondary outcomes included fasting and stimulated C-peptide level, daily insulin dosage, and clinical remission. The revised Cochrane risk of bias tool was used for quality assessment, and meta-analyses were conducted to evaluate the efficacy of the BCG vaccine.

RESULTS

Four studies with a total of 198 subjects were included. The results of HbA1c and fasting C-peptide levels were extracted for further quantitative assessment. The pooled meta-analysis demonstrated no significant difference in HbA1c levels (mean difference [MD], -0.12; 95% confidence interval [CI], -0.53 to 0.30; I ² = 56%) or fasting C-peptide levels (MD, -0.15; 95% CI, -0.35 to 0.06; I ² = 0%) in the BCG intervention group as compared with that in the placebo group.

CONCLUSIONS

There is no robust evidence to support the use of the BCG vaccine for the treatment of T1DM although the HbA1c levels tended to improve. Additional RCTs to assess the long-term effects of the BCG vaccine on glycemic control are warranted.

Gene Expression Analysis of the Pre-Diabetic Pancreas to Identify Pathogenic Mechanisms and Biomarkers of Type 1 Diabetes

Type 1 Diabetes (T1D) occurs as a result of the autoimmune destruction of pancreatic β-cells by self-reactive T cells. The etiology of this disease is complex and difficult to study due to a lack of disease-relevant tissues from pre-diabetic individuals. In this study, we performed gene expression analysis on human pancreas tissues obtained from the Network of Pancreatic Organ Donors with Diabetes (nPOD), and showed that 155 genes were differentially expressed by ≥2-fold in the pancreata of autoantibody-positive (AA+) at-risk individuals compared to healthy controls. Only 48 of these genes remained changed by ≥2-fold in the pancreata of established T1D patients. Pathway analysis of these genes showed a significant association with various immune pathways. We were able to validate the differential expression of eight disease-relevant genes by QPCR analysis: A significant upregulation of CADM2, and downregulation of TRPM5, CRH, PDK4, ANGPL4, CLEC4D, RSG16, and FCGR2B was confirmed in the pancreata of AA+ individuals versus controls. Studies have already implicated FCGR2B in the pathogenesis of disease in non-obese diabetic (NOD) mice. Here we showed that CADM2, TRPM5, PDK4, and ANGPL4 were similarly changed in the pancreata of pre-diabetic 12-week-old NOD mice compared to NOD.B10 controls, suggesting a possible role for these genes in the pathogenesis of both T1D and NOD disease. The loss of the leukocyte-specific gene, FCGR2B, in the pancreata of AA+ individuals, is particularly interesting, as it may serve as a potential whole blood biomarker of disease progression. To test this, we quantified FCGR2B expression in peripheral blood samples of T1D patients, and AA+ and AA- first-degree relatives of T1D patients enrolled in the TrialNet Pathway to Prevention study. We showed that FCGR2B was significantly reduced in the peripheral blood of AA+ individuals compared to AA- controls. Together, these findings demonstrate that gene expression analysis of pancreatic tissue and peripheral blood samples can be used to identify disease-relevant genes and pathways and potential biomarkers of disease progression in T1D.

Past, present and future of latent autoimmune diabetes in adults

Latent autoimmune diabetes in adults (LADA) is the most common form of autoimmune diabetes diagnosed in adults. Similar to type 1 diabetes, the prevalence of LADA is impacted by ethnicity and geography. LADA is characterized by β cell loss due to autoimmunity and insulin resistance and has highly heterogeneous clinical features, autoimmunity, and genetics in a glutamic acid decarboxylase antibody (GADA) titre-dependent manner, suggesting LADA is part of a continuum spectrum between type 1 and type 2 diabetes. Although LADA is the most frequent form of autoimmune diabetes diagnosed in adults, clinical trials involving LADA are scarce. Here we review the recent advancements in LADA epidemiology, clinical features, pathogenesis, and interventions. We also highlight the environmental factors that are thought to play an important role in addition to genetics in the pathogenesis of LADA. In the future, high-throughput molecular profiles might shed light on the nature of LADA among the wide spectrum of diabetes and offer new opportunities to identify novel LADA-specific biomarkers.

Modulatory Mechanisms of the NLRP3 Inflammasomes in Diabetes

The inflammasome is a multiprotein complex that acts to enhance inflammatory responses by promoting the production and secretion of key cytokines. The best-known inflammasome is the NLRP3 (nucleotide-binding oligomerization domain-like receptor [NLR] family pyrin domain-containing 3) inflammasome. The evidence has shown that the NLRP3 inflammasome, IL-1β, thioredoxin-interacting protein (TXNIP), and pyroptosis play vital roles in the development of diabetes. This review summarizes the regulation of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) by NLRP3 via modulation of glucose tolerance, insulin resistance, inflammation, and apoptosis mediated by endoplasmic reticulum stress in adipose tissue. Moreover, NLRP3 participates in intestinal homeostasis and inflammatory conditions, and NLRP3-deficient mice experience intestinal lesions. The diversity of an individual's gut microbiome and the resultant microbial metabolites determines the extent of their involvement in the physiological and pathological mechanisms within the gut. As such, further study of the interaction between the NLRP3 inflammasome and the complex intestinal environment in disease development is warranted to discover novel therapies for the treatment of diabetes.

Human Antigen Leucocyte (HLA)-G and HLA-E are differentially expressed in pancreatic disorders

BACKGROUND

Little information is available regarding the expression of the immunomodulatory Human Leukocyte Antigen (HLA)-G and -E molecules in pancreatic disorders.

AIM

To analyze HLA-G and -E expression in specimens of alcoholic chronic pancreatitis (ACP), idiopathic chronic pancreatitis (ICP), type 1 (T1D) and type 2 diabetes (T2D) and in histologically normal pancreas (HNP).

METHODS

HLA-G and -E expression (ACP = 30, ICP = 10, T1D = 10, T2D = 30 and HNP = 20) was evaluated by immunohistochemistry in three different areas (acini, islets and inflammatory infiltrate).

RESULTS

Acini and islets from HNP specimens exhibited higher HLA-G and -E expression compared to corresponding areas from all other patient groups. In inflammatory infiltrate, HLA-G and -E expression was observed only among the pancreatic disorders. We observed higher HLA-G and -E expression in acini from T2D compared to ACP, as well as higher HLA-G expression compared to ICP.

CONCLUSION

The decreased expression of HLA-G and -E in islets and acini together with the expression of these molecules in the inflammatory infiltrating cells were shared features among chronic inflammatory and autoimmune pancreatic disorders evaluated in this study, possibly reflecting tissue damage.

Cows Get Crohn's Disease and They're Giving Us Diabetes

Increasingly, Johne's disease of ruminants and human Crohn's disease are regarded as the same infectious disease: paratuberculosis. Mycobacterium avium ss. paratuberculosis (MAP) is the cause of Johne's and is the most commonly linked infectious cause of Crohn's disease. Humans are broadly exposed to MAP in dairy products and in the environment. MAP has been found within granulomas such as Crohn's disease and can stimulate autoantibodies in diseases such as type 1 diabetes (T1D) and Hashimoto's thyroiditis. Moreover, beyond Crohn's and T1D, MAP is increasingly associated with a host of autoimmune diseases. This article suggests near equivalency between paucibacillary Johne's disease of ruminant animals and human Crohn's disease and implicates MAP zoonosis beyond Crohn's disease to include T1D.

Targeting Inflammation by Flavonoids: Novel Therapeutic Strategy for Metabolic Disorders

A balanced metabolic profile is essential for normal human physiological activities. Disproportions in nutrition give rise to imbalances in metabolism that are associated with aberrant immune function and an elevated risk for inflammatory-associated disorders. Inflammation is a complex process, and numerous mediators affect inflammation-mediated disorders. The available clinical modalities do not effectively address the underlying diseases but rather relieve the symptoms. Therefore, novel targeted agents have the potential to normalize the metabolic system and, thus, provide meaningful therapy to the underlying disorder. In this connection, polyphenols, the well-known and extensively studied phytochemical moieties, were evaluated for their effective role in the restoration of metabolism via various mechanistic signaling pathways. The various flavonoids that we observed in this comprehensive review interfere with the metabolic events that induce inflammation. The mechanisms via which the polyphenols, in particular flavonoids, act provide a promising treatment option for inflammatory disorders. However, detailed clinical studies of such molecules are required to decide their clinical fate.

Incidence, prevalence and clinical manifestations at onset of juvenile diabetes in Tanzania

Better knowledge on incidence, prevalence and clinical manifestations is needed for planning diabetes care in Sub Saharan Africa.

AIMS

To find a crude incidence/prevalence of diabetes in children and young adults in a low resource setting, classify the diabetes and audit the health record keeping.

METHODS

A retrospective observational study based on medical recordings 2010-2016. Target population was children and adolescent registered in Changing Diabetes in Children (CDiC) or Life for a Child (LFAC) programs for children with T1DM and diagnosed at 5 diabetes clinics in three geographical regions of Tanzania. 604 patients' files were available from five hospitals.

RESULTS

336/604 files covered patients <15 years of age at diagnosis. The prevalence of diabetes <15 years of age ranged from 10.1 to 11.9 per 100,000 children and the annual incidence 1.8-1.9/100,000 children, with peak incidence at 10-14 years. A lot of data were missing. The great majority of the patients presented with typical signs and symptoms of T1D, 83.7% with plausible ketoacidosis (DKA).

CONCLUSIONS

Diabetes incidence and prevalence is still low. T1D seems to dominate with very high frequency of DKA at diagnosis. Increased awareness of diabetes both in health care and community is needed.

A GLIS3-CD133-WNT-signaling axis regulates the self-renewal of adult murine pancreatic progenitor-like cells in colonies and organoids

The existence and regenerative potential of resident stem and progenitor cells in the adult pancreas are controversial topics. A question that has been only minimally addressed is the capacity of a progenitor cell to self-renew, a key attribute that defines stem cells. Previously, our laboratory has identified putative stem and progenitor cells from the adult murine pancreas. Using an ex vivo colony/organoid culture system, we demonstrated that these stem/progenitor-like cells have self-renewal and multilineage differentiation potential. We have named these cells pancreatic colony-forming units (PCFUs) because they can give rise to three-dimensional colonies. However, the molecular mechanisms by which PCFUs self-renew have remained largely unknown. Here, we tested the hypothesis that PCFU self-renewal requires GLIS family zinc finger 3 (GLIS3), a zinc-finger transcription factor important in pancreas development. Pancreata from 2- to 4-month-old mice were dissociated, sorted for CD133^highCD71^low ductal cells, known to be enriched for PCFUs, and virally transduced with shRNAs to knock down GLIS3 and other proteins. We then plated these cells into our colony assays and analyzed the resulting colonies for protein and gene expression. Our results revealed a previously unknown GLIS3-to-CD133-to-WNT signaling axis in which GLIS3 and CD133 act as factors necessary for maintaining WNT receptors and signaling molecules in colonies, allowing responses to WNT ligands. Additionally, we found that CD133, but not GLIS3 or WNT, is required for phosphoinositide 3-kinase (PI3K)/AKT Ser/Thr kinase (AKT)-mediated PCFU survival. Collectively, our results uncover a molecular pathway that maintains self-renewal of adult murine PCFUs.

Loss of MafA and MafB expression promotes islet inflammation

Maf transcription factors are critical regulators of beta-cell function. We have previously shown that reduced MafA expression in human and mouse islets is associated with a pro-inflammatory gene signature. Here, we investigate if the loss of Maf transcription factors induced autoimmune processes in the pancreas. Transcriptomics analysis showed expression of pro-inflammatory as well as immune cell marker genes. However, clusters of CD4+ T and B220+ B cells were associated primarily with adult MafA^−/−MafB^+/−, but not MafA^−/− islets. MafA expression was detected in the thymus, lymph nodes and bone marrow suggesting a novel role of MafA in regulating immune-cell function. Analysis of pancreatic lymph node cells showed activation of CD4+ T cells, but lack of CD8+ T cell activation which also coincided with an enrichment of naïve CD8+ T cells. Further analysis of T cell marker genes revealed a reduction of T cell receptor signaling gene expression in CD8, but not in CD4+ T cells, which was accompanied with a defect in early T cell receptor signaling in mutant CD8+ T cells. These results suggest that loss of MafA impairs both beta- and T cell function affecting the balance of peripheral immune responses against islet autoantigens, resulting in local inflammation in pancreatic islets.

Dynamic Immune Phenotypes of B and T Helper Cells Mark Distinct Stages of T1D Progression

Multiple studies of B- and T-cell compartments and their response to stimuli demonstrate alterations in established type 1 diabetes (T1D). Yet it is not known whether these alterations reflect immune mechanisms that initiate islet autoimmunity, promote disease progression, or are secondary to disease. To address these questions, we used samples from the TrialNet Pathway to Prevention study to investigate T-cell responses to interleukin (IL)-2 and regulatory T cell-mediated suppression, the composition of the B-cell compartment, and B-cell responses to B-cell receptor and IL-21 receptor engagement. These studies revealed stage-dependent T- and B-cell functional and immune phenotypes; namely, early features that differentiate autoantibody-positive at-risk first-degree relatives (FDRs) from autoantibody-negative FDRs and persisted through clinical diagnosis; late features that arose at or near T1D diagnosis; and dynamic features that were enhanced early and blunted at later disease stages, indicating evolving responses along the continuum of T1D. We further explored how these specific phenotypes are influenced by therapeutic interventions. Our integrated studies provide unique insights into stable and dynamic stage-specific immune states and define novel immune phenotypes of potential clinical relevance.

Deletion of pancreatic β-cell adenosine kinase improves glucose homeostasis in young mice and ameliorates streptozotocin-induced hyperglycaemia

Severe reduction in the β‐cell number (collectively known as the β‐cell mass) contributes to the development of both type 1 and type 2 diabetes. Recent pharmacological studies have suggested that increased pancreatic β‐cell proliferation could be due to specific inhibition of adenosine kinase (ADK). However, genetic evidence for the function of pancreatic β‐cell ADK under physiological conditions or in a pathological context is still lacking. In this study, we crossed mice carrying LoxP‐flanked Adk gene with Ins2‐Cre mice to acquire pancreatic β ‐cell ADK deficiency (Ins2‐Cre^±Adk^fl/fl) mice. Our results revealed that Ins2‐Cre^+/‐Adk^fl/fl mice showed improved glucose metabolism and β‐cell mass in younger mice, but showed normal activity in adult mice. Moreover, Ins2‐Cre^±Adk^fl/fl mice were more resistant to streptozotocin (STZ) induced hyperglycaemia and pancreatic β‐cell damage in adult mice. In conclusion, we found that ADK negatively regulates β‐cell replication in young mice as well as under pathological conditions, such as STZ induced pancreatic β‐cell damage. Our study provided genetic evidence that specific inhibition of pancreatic β‐cell ADK has potential for anti‐diabetic therapy.

Current Status on Immunological Therapies for Type 1 Diabetes Mellitus

PURPOSE OF REVIEW

Type 1 diabetes (T1D) occurs when there is destruction of beta cells within the islets of Langerhans in the pancreas due to autoimmunity. It is considered a complex disease, and different complications can surface and worsen the condition if T1D is not managed well. Since it is an incurable disease, numerous treatments and therapies have been postulated in order to control T1D by balancing hyperglycemia control while minimizing hypoglycemic episodes. The purpose of this review is to primarily look into the current state of the available immunological therapies and their advantages for the treatment of T1D.

RECENT FINDINGS

Over the years, immunological therapy has become the center of attraction to treat T1D. Immunomodulatory approaches on non-antigens involving agents such as cyclosporine A, mycophenolate mofetil, anti-CD20, cytotoxic T cells, anti-TNF, anti-CD3, and anti-thymocyte globulin as well as immunomodulative approaches on antigens such as insulin, glutamic acid decarboxylase, and heat shock protein 60 have been studied. Aside from these two approaches, studies and trials have also been conducted on regulatory T cells, dendritic cells, interleukin 2, interleukin 4, M2 macrophages, and rapamycin/interleukin 2 combination therapy to test their effects on patients with T1D. Many of these agents have successfully suppressed T1D in non-obese diabetic (NOD) mice and in human trials. However, some have shown negative results. To date, the insights into the management of the immune system have been increasing rapidly to search for potential therapies and treatments for T1D. Nevertheless, some of the challenges are still inevitable. A lot of work and effort need to be put into the investigation on T1D through immunological therapy, particularly to reduce complications to improve and enhance clinical outcomes.

Multiplexed In Situ Imaging Mass Cytometry Analysis of the Human Endocrine Pancreas and Immune System in Type 1 Diabetes

The interaction between the immune system and endocrine cells in the pancreas is crucial for the initiation and progression of type 1 diabetes (T1D). Imaging mass cytometry (IMC) enables multiplexed assessment of the abundance and localization of more than 30 proteins on the same tissue section at 1-μm resolution. Herein, we have developed a panel of 33 antibodies that allows for the quantification of key cell types including pancreatic exocrine cells, islet cells, immune cells, and stromal components. We employed this panel to analyze 12 pancreata obtained from donors with clinically diagnosed T1D and 6 pancreata from non-diabetic controls. In the pancreata from donors with T1D, we simultaneously visualized significant alterations in islet architecture, endocrine cell composition, and immune cell presentation. Indeed, we demonstrate the utility of IMC to investigate complex events on the cellular level that will provide new insights on the pathophysiology of T1D.

Reversal of New Onset Type 1 Diabetes by Oral Salmonella-Based Combination Therapy and Mediated by Regulatory T-Cells in NOD Mice

Autoimmune diseases such as type 1 diabetes (T1D) involve the loss of regulatory mechanisms resulting in increased tissue-specific cytotoxicity. The result is destruction of pancreatic insulin-producing β-cells and loss of glucose homeostasis. We are developing a novel oral vaccine using live attenuated Salmonella to deliver TGFβ, IL10, and the diabetic autoantigen preproinsulin combined with low-doses of anti-CD3 mAb. Here we show that oral administration of Salmonella-based anti-CD3 mAb combined therapy reverses new-onset T1D in non-obese diabetic (NOD) mice. The therapeutic effect of the combined therapy was associated with induction of immune suppressive CD4⁺CD25⁺Foxp3⁺ Treg and CD4⁺CD49b⁺LAG3⁺ Tr1 cells. In adoptive transfer experiments, adding or depleting Treg or Tr1 cells indicated that both are important for preventing diabetes in combined therapy-treated mice, but that Tr1 cells may have a more central role. Furthermore, induced Tr1 cells were found to be antigen-specific responding to peptide stimulation by secreting tolerance inducing IL10. These preclinical data demonstrate a role for Treg and Tr1 cells in combined therapy-mediated induction of tolerance in NOD mice. These results also demonstrate the potential of oral Salmonella-based combined therapy in the treatment of early T1D.

The role of ERAP1 in autoinflammation and autoimmunity

Autoimmune and autoinflammatory diseases affect millions worldwide. These classes of disease involve abnormal immune activation of both the innate and adaptive immune systems. While both classes of disease represent a spectrum of aberrant immune activation, excessive activation of the innate immune system has been considered causal for the inflammation and tissue damage found in autoinflammatory diseases, while excessive activation of the adaptive immune system has been thought to primarily contribute to end-organ symptoms noted in autoimmune diseases. Interestingly, the endoplasmic reticulum aminopeptidase 1 (ERAP1) protein, well known for its aminopeptidase function as a "molecular ruler", trimming peptides prior to their loading onto MHC-I molecules for antigen presentation in the ER, has also been shown to be genetically associated with both autoinflammatory and autoimmune diseases. Indeed, this multifaceted protein has been found to have many functions that affect both the innate and adaptive immune responses. In this review, we summarize these findings, with an attempt to identify the possible ERAP1 dependent mechanisms responsible for the pathogenesis of multiple, ERAP1 associated diseases.

Stem-cell based organ-on-a-chip models for diabetes research

Diabetes mellitus (DM) ranks among the severest global health concerns of the 21st century. It encompasses a group of chronic disorders characterized by a dysregulated glucose metabolism, which arises as a consequence of progressive autoimmune destruction of pancreatic beta-cells (type 1 DM), or as a result of beta-cell dysfunction combined with systemic insulin resistance (type 2 DM). Human cohort studies have provided evidence of genetic and environmental contributions to DM; yet, these studies are mostly restricted to investigating statistical correlations between DM and certain risk factors. Mechanistic studies, on the other hand, aimed at re-creating the clinical picture of human DM in animal models. A translation to human biology is, however, often inadequate owing to significant differences between animal and human physiology, including the species-specific glucose regulation. Thus, there is an urgent need for the development of advanced human in vitro models with the potential to identify novel treatment options for DM. This review provides an overview of the technological advances in research on DM-relevant stem cells and their integration into microphysiological environments as provided by the organ-on-a-chip technology.

An Overview on Probiotics as an Alternative Strategy for Prevention and Treatment of Human Diseases

Probiotics are viable and useful microorganisms, which are beneficial factors for human and animal health by altering their microbial flora. Most of the probiotics belong to a large group of bacteria in the human gastrointestinal tract. There are several clinical shreds of evidence that show anti-carcinogenic effects of probiotics through altering digestive enzymes, inhibition of carcinogenic agents, and modulating the immune responses in experimental animals. Many studies have been performed to evaluate the potential effectiveness of probiotics in treating or preventing neurological diseases such as MS and novel treatment modality for T1D. The purpose of this study is to have an overview on probiotic microorganisms and to review the previous researches on the effects of probiotics on health through currently available literatures. The study was performed using following keywords; Probiotics, Cancer, Immune system, Multiple Sclerosis (MS) and Diabetes mellitus. PubMed/Medline, Clinicaltrials.gov, Ovid, Google Scholar, and Reaxcys databases used to find the full text of related articles. According to the current available data on probiotics and related health-promoting benefits, it seems that, consumption of probiotics can lead to the prevention and reduction the risk of cancer, diabetes, and multiple sclerosis. Although for the better and more decisive conclusion, there is a need to larger sample size clinical studies with more focus on the safety of these biological agents and their possible beneficial effects on different population.

An Insight Into the Intestinal Web of Mucosal Immunity, Microbiota, and Diet in Inflammation

The rising global incidence of autoimmune and inflammatory conditions can be attributed to changes in the large portion of the immune system that belongs to our gastrointestinal tract (GI). The intestinal immune system serves as a gatekeeper to prevent pathogenic invasions and to preserve a healthier gut microbiota. The gut microbiota has been increasingly studied as a fundamental contributor to the state of health and disease. From food fermentation, the gut microbiota releases metabolites or short chain fatty acids (SCFAs), which have anti-inflammatory properties and preserve gut homeostasis. Immune responses against food and microbial antigens can cause inflammatory disorders such as inflammatory bowel disease (IBD) and celiac disease. As such, many autoimmune and inflammatory diseases also have a “gut origin”. A large body of evidence in recent years by ourselves and others has uncovered the link between the immune system and the SCFAs in specific diseases such as autoimmune type 1 diabetes (T1D), obesity and type 2 diabetes (T2D), cardiovascular disease, infections, allergies, asthma, and IBD. Thus, the power of these three gut dynamic components—the mucosal immunity, the microbiota, and diet—can be harnessed in tandem for the prevention and treatment of many inflammatory and infectious diseases.

Factors affecting Salmonella-based combination immunotherapy for prevention of type 1 diabetes in non-obese diabetic mice

We previously reported the development of an oral vaccine for diabetes based on live attenuated Salmonella-expressing preproinsulin (PPI) as the autoantigen. When combined with host cell-expressed TGFβ, the vaccine prevented the onset of diabetes in non-obese diabetic (NOD) mice. Herein, we investigated factors that could affect vaccine efficacy including vaccination number, optimization of the autoantigen codon sequence, Salmonella SPI2-TTSS promoter/effector combinations, concurrent short-course low-dose anti-CD3. We also evaluated autoantigen GAD65 and cytokine IL10 treatment upon vaccine efficacy. T-cells we employed to elucidate the mechanism of the vaccine action. Our results showed that GAD65+TGFβ or PPI+TGFβ+IL10 prevented the onset of diabetes in the NOD mice and maintained glucose tolerance. However, increasing the number of vaccine doses, codon-optimization of the autoantigen(s) or use of other Salmonella promoter/effector combinations had no in vivo effect. Interestingly, two doses of vaccine (PPI+TGFβ+IL10) combined with a sub-therapeutic dose of anti-CD3 prevented diabetes and decreased hyperglycemia in mice. The combined therapy also increased splenic Tregs and local Tregs in pancreatic lymph nodes (PLN) and increased regulatory (IL10 and IL2) but reduced inflammatory (IFNγ and TNFα) cytokines. Together, these results indicate that the combination of low vaccine dose number, less vaccine autoantigen expression and short-course low-dose anti-CD3 can increase regulatory mechanisms and suppress autoimmunity.

Immune Response to Extracellular Vesicles From Human Islets of Langerhans in Patients With Type 1 Diabetes

The autoimmune response that characterizes type 1 diabetes (T1D) has no clear cause. Extracellular vesicles (EVs) play an important role in triggering the immune response in other contexts. Here, we propose a model by which EVs isolated from human islets stimulate proinflammatory immune responses and lead to peripheral blood mononuclear cell (PBMC) activation. We show that human islet EVs are internalized by monocytes and B cells and lead to an increase in T-helper 1, 2, and 17 cytokine expression, as well as T and B cell proliferation. Importantly, we demonstrate memory T and B cell activation by EVs selectively in PBMCs of patients with T1D. Additionally, human islet EVs induce an increase in antibodies against glutamic acid decarboxylase 65 (GAD65) in T1D PBMCs. Furthermore, pretreatment of T1D PBMCs with ibrutinib, an inhibitor of Bruton tyrosine kinase, dampens EV-induced memory B cell activation and GAD65 antibody production. Collectively, our findings indicate a role for human islet EVs in mediating activation of B and T cells and GAD65 autoantibody production.

Healthy Donor Polyclonal IgMs Diminish B-Lymphocyte Autoreactivity, Enhance Regulatory T-Cell Generation, and Reverse Type 1 Diabetes in NOD Mice

Autoimmune diseases such as type 1 diabetes (T1D) arise from unrestrained activation of effector lymphocytes that destroy target tissues. Many efforts have been made to eliminate these effector lymphocytes, but none has produced a long-term cure. An alternative to depletion therapy is to enhance endogenous immune regulation. Among these endogenous alternatives, naturally occurring Igs have been applied for inflammatory disorders but have lacked potency in antigen-specific autoimmunity. We hypothesized that naturally occurring polyclonal IgMs, which represent the majority of circulating, noninduced antibodies but are present only in low levels in therapeutic Ig preparations, possess the most potent capacity to restore immune homeostasis. Treatment of diabetes-prone NOD mice with purified IgM isolated from Swiss Webster (SW) mice (nIgM_SW) reversed new-onset diabetes, eliminated autoreactive B lymphocytes, and enhanced regulatory T-cell (Treg) numbers both centrally and peripherally. Conversely, IgM from prediabetic NOD mice could not restore this endogenous regulation, which represents an unrecognized component of T1D pathogenesis. Of note, IgM derived from healthy human donors was similarly able to expand human CD4 Tregs in humanized mice and produced permanent diabetes protection in treated NOD mice. Overall, these studies demonstrate that a potent, endogenous regulatory mechanism, nIgM, is a promising option for reversing autoimmune T1D in humans.

Lifestyle Factors Affecting the Gut Microbiota's Relationship with Type 1 Diabetes

PURPOSE OF REVIEW

The incidence of type 1 diabetes (T1D) is rising drastically for the past decades at a rate that cannot be explained by genetic changes alone. Environmental changes are considered to be the main drivers of this change. Recently, the gut microbiota has been suggested as a missing link between known environmental disease modulators and T1D promotion. Lifestyle factors have changed over time and have altered the gut microbiota-host interaction affecting T1D development. The purpose of this review is to discuss recent data emphasizing the modulatory potential of early lifestyle factors on gut microbiota and to elucidate their implication for T1D.

RECENT FINDINGS

Recent findings show that lifestyle factors, especially those that affect the early establishment of gut homeostasis and the education of the immune system, are crucial disease modulators. Changing lifestyle factors affecting the early establishment of gut homeostasis are suggested to be key drivers of the rising T1D incidence.

A Contrast in Pathogenic Responses between C57BL/6J and BALB/cJ Mice Using a Model of Retinal Injury

Ischemia is associated with the pathogenesis of retinal disease, including diabetic retinopathy and glaucoma. As a result, the retinal ischemia/reperfusion injury model has been used to study neurovascular changes. Historically, murine models of retinal disease are established in C57BL/6J (B6) mice, which have been described as type 1-dominant responders. In bacterial keratitis models, B6 mice are susceptible, whereas BALB/cJ (BALB/c; type 2-dominant) mice exhibit a resistant phenotype. As such, we questioned whether the type 1/type 2 paradigm could be extrapolated to events associated with retinal pathogenesis. The current study compares the retinal response of B6 with BALB/c mice to investigate strain-specific differences. Retinas were collected at 2 and 10 days after ischemia/reperfusion injury to examine differences in neurovascular degeneration, leukostasis, oxidative stress, glial activation, and select inflammatory mediators. Although both strains showed signs of retinal injury, significantly more damage was observed in B6 mice. Retinal thickness was reduced and vascular damage was more severe in B6 mice. Exacerbated response to injury in B6 versus BALB/c retinas was further supported by increased leukostasis, inflammatory mediators, reactive oxygen species, and lipid peroxidation. In addition, more terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells and increased glial activation were detected in B6 mice. These data indicate that B6 and BALB/c retinas differentially respond to injury, which has broader implications regarding the development and study of retinal diseases.

Oral insulin does not alter gut microbiota composition of NOD mice

BACKGROUND

Oral insulin as a preventive strategy and/or treatment of type 1 diabetes has been the target of much research. Producing oral insulins is a complex and challenging task, with numerous pitfalls, due to physiological, physical, and biochemical barriers. Our aim was to determine the impact of oral insulin on the delicate gut microbiota composition.

METHODS

Female nonobese diabetic mice were given oral porcine insulin 2 times a week from 5 weeks of age for 4 weeks, and then subsequently once a week for 21 weeks, or until euthanized. The mice were divided into groups on a gluten-reduced diet or a standard diet. Gut microbiota composition was analysed based on faecal samples, and the type 1 diabetes incidence of the mice was monitored.

RESULTS

We observed no influence of the oral porcine insulin on the gut microbiota composition of mice on a gluten-reduced or a standard diet at 9 weeks of age. Also, the administration of oral insulin did not influence the incidence of type 1 diabetes at 30 weeks of age.

CONCLUSIONS

Oral porcine insulin does not alter the gut microbiota composition of nonobese diabetic mice on either a gluten-reduced diet or standard diet. Also, the oral porcine insulin did not influence the incidence of type 1 diabetes in the groups.

Immune Mechanisms and Pathways Targeted in Type 1 Diabetes

PURPOSE OF REVIEW

The immunosuppressive agent cyclosporine was first reported to lower daily insulin dose and improve glycemic control in patients with new-onset type 1 diabetes (T1D) in 1984. While renal toxicity limited cyclosporine's extended use, this observation ignited collaborative efforts to identify immunotherapeutic agents capable of safely preserving β cells in patients with or at risk for T1D.

RECENT FINDINGS

Advances in T1D prediction and early diagnosis, together with expanded knowledge of the disease mechanisms, have facilitated trials targeting specific immune cell subsets, autoantigens, and pathways. In addition, clinical responder and non-responder subsets have been defined through the use of metabolic and immunological readouts. Herein, we review emerging T1D biomarkers within the context of recent and ongoing T1D immunotherapy trials. We also discuss responder/non-responder analyses in an effort to identify therapeutic mechanisms, define actionable pathways, and guide subject selection, drug dosing, and tailored combination drug therapy for future T1D trials.