Destruction Of Beta Cells Research Articles

I. How can you choose the fate of iPSCs and stem cells, Regeneration or Carcinogenesis? A hypothetical insight.: II. Modelling human beta cell development with pluripotent stem cells.

It is nowadays taken granted that induced pluripotent stem cells (iPSCs) are available for the regeneration therapy since iPSCs differentiate into any kind of phenotypes. If iPSCs can choose their fate in every way of differentiation why they do not choose cancer phenotype. As a body develops for one fertilized egg, embryonic stem cell must choose every phenotype of tissues such as blood, neuron, lung, liver, pancreas and so on depending on the stages. And sometimes the cells get cancer. So do iPSCs because iPSCs are almost equivalent to embryonic cells. Then how can the safety of the regeneration therapy be maintained with iPSCs? When inducing the differentiation of iPSCs it is considered important to choose the proper conditions of culture such as 3D-platform for embryoid, supplement of cytokines and growth factors, inhibition of signaling and so on. On the other hand, several conditions have been reported to induce cancer stem cells. The cancer inducing conditions are possibly summarized as the factors chronically exposed to iPSCs. It is further worthwhile noticing that the conditions do not appear to induce mutations but affecting the epigenetics. Collectively, to secure the safety of regeneration therapy, it appears the best way to avoid the conditions to induce cancer stem cells. Further insights in details will be discussed in the lecture. Type 1 Diabetes (T1D) is an autoimmune disease characterized by destruction of the pancreatic beta cells and loss of insulin. Using the Edmonton protocol, donor-derived islets seeded into the liver successfully restore glycemia in 58% of T1D patients. However, donor scarcity, risks associated with immunosuppressants and poor engraftment limit this therapeutic application to a small number of patients. To overcome these challenges, the developmental potential of human embryonic stem cells and human induced pluripotent stem cells is being harnessed to produce surrogate islets in vitro. We and others have been able to mimic human embryonic development and generate pancreatic progenitors (PP) that have the ability to mature into insulin-producing beta-like cells both in vitro and in vivo. Transplantation of pancreatic progenitors in the kidney capsule of immunodeficient mice leads to formation of islet-like structures that secrete human insulin. However, there are some limitations to the use of pancreatic progenitors for the treatment of T1D. First and foremost, their safety as the PP population can be heterogenous and highly proliferative, which might lead to formation of cellular outgrowth or teratoma after transplantation. Second, while insulin-producing cells develop in vivo 6 weeks after transplantation, restoration of normoglycemia occurs ~5 months later, suggesting that these "early" insulin-producing cells are immature, or poorly connected to the host vasculature. We have been addressing these two limitations and developed approaches to 1) improve safety by identifying markers to purify the PP populations and 2) accelerate functionality by improving vascularization at the time of transplantation.

Type 1 diabetes mellitus in patients with recurrent acute and chronic pancreatitis: A case series

Background/objectivesPancreatogenic diabetes mellitus has been assumed to result from non-immune beta cell destruction when the pancreas is replaced by fibrotic tissue secondary to acute and chronic pancreatitis. We hypothesize that recurrent episodes of pancreatic inflammation may increase the risk for developing β-cell autoimmunity in susceptible individuals. MethodsWe describe 11 patients who had both recurrent acute and/or chronic pancreatitis and type 1 diabetes (T1D) requiring insulin therapy. ResultsAll 11 patients had positive autoantibodies and 8 patients tested had minimal to undetectable (7/8) or moderate (1/8) stimulated C-peptide at 12 months after T1D onset. Three had biopsy confirmation of insulitis. ConclusionsThese cases lend support to the theory that pancreatitis may increase risk for T1D. We postulate that the pro-inflammatory conditions of pancreatitis may increase posttranslational protein modifications of β-cell antigens and neoepitope generation, which are potential initiating events for loss of β-cell self-tolerance.

Insulin Modulates Inflammatory Cytokine Release in Acute Stages and Augments Expression of Adhesion Molecules and Leukocytes in Lungs on Chronic Stages of Paracoccidioidomycosis.

Type 1 diabetes mellitus (T1D) is caused by partial destruction of the insulin-producing beta cells in the pancreas and is a major issue for public health care worldwide. Reduced or impaired immunological responses, which render patients more susceptible to infections, have been observed in T1D, and this dysfunction is often related to a lack of insulin in the blood. Paracoccidioidomycosis is an important systemic mycosis endemic in Latin America. To evaluate the effects of T1D on this fungal infection and the modulatory effects of insulin, we induced diabetes in C57Bl/6 male mice (alloxan, 60 mg/kg), infected the mice (Pb18, 1 x 106 cells), and treated the mice with neutral protamine Hagedorn (NPH) insulin (2 IU/600 mg/dL blood glucose). Twenty-four hours after infection, infected diabetic mice showed reduced secretion of interferon (IFN)-γ and interleukine (IL)-12 p70 compared to infected nondiabetic controls. On the 45th day of infection, infected diabetic mice presented higher IFN-γ levels, a higher tumor necrosis factor (TNF)-α:IL-10 ratio, and lower adhesion molecule expression levels than nondiabetic mice. In the in vitro experiments, alveolar macrophages from diabetic animals showed reduced phagocytic activity compared to those from control animals at 4, 12, and 24 h. In infected diabetic mice, treatment with insulin restored IL-12 p70 levels at 24 h of infection, reduced IFN-γ levels and the TNF-α:IL-10 ratio at 45 days, and restored vascular cell adhesion molecule (VCAM)-1 expression in pulmonary blood vessels, and this treatment reduced the diminished phosphorylation of extracellular signal-regulated kinases (ERK) and increased nuclear factor-kappa-B(iκb)-α and jun amino-terminal kinases (JNK) p46 levels in infected nondiabetic mice. In addition, insulin promoted increased phagocytic activity in the alveolar macrophages of diabetic mice. These data suggest that T1D mice are more susceptible to Pb18 infection and that insulin modulates this inflammation in diabetic mice by augmenting the expression of adhesion molecules and leukocytes in the lungs and by reducing chronic inflammation.

Role of Adiponectin and Tumor Necrosis Factor-Alpha in the Pathogenesis and Evolution of Type 1 Diabetes Mellitus in Children and Adolescents.

Type 1 diabetes mellitus (T1DM) is a complex condition caused by the destruction of pancreatic beta cells by autoimmune mechanisms. As a result, insulin deficiency and subsequent hyperglycemia occur. The aim of the present study is to investigate the role of adiponectin and tumor necrosis factor alpha (TNF-α) in the development of T1DM. The study is designed as an observational case-control study, involving 52 diabetic patients and 66 controls. Z scores for Body Mass Index (BMI), weight, height, and adiponectin and TNF-α serum levels were assessed in both groups. The T1DM group had significantly higher TNF-α levels and a significantly higher proportion of high-risk patients for inflammation based on TNF-α values as compared to the control group, while both groups had statistically similar adiponectin levels and a similar proportion of high/medium-risk patients based on adiponectin values. TNF-α plays a significant role in the pathogenesis and evolution of T1DM and it may represent an additional marker of disease progression, as well as a potential target of immunotherapeutic strategies. In the present study, no statistically significant differences were recorded in adiponectin levels neither in diabetic patients and controls, nor in high/medium severity risk diabetic patients.

Prevalence of IA-2 antibody in patients suffering from diabetes and their first-degree relatives

Type 1 diabetes mellitus (T1DM) is an autoimmune disorder accompanied by activation of auto-reactive B cells, autoantibody production, and consequently insulin-producing beta cell destruction. Some evidences support the value of autoantibodies such as anti-islet cell antigen (IA-2) auto-antibody in T1DM diagnosis and prognosis. The present study investigated the presence of IA-2 antibody in T1DM patients and their first-degree relatives as well as T2DM patients and healthy people to evaluate the diagnostic and prognostic value of anti-IA-2 in T1DM. In total 264 cases including 38 T1DM patients, 36 first-degree relatives, 88 T2DM patients, and 102 age-/sex-matched healthy controls participated in this study. After venous blood collection, sera were isolated and the level of IA-2 antibody was measured by ELISA method. Routine hematologic and biochemical tests including complete blood count (CBC), fasting blood sugar (FBS), hemoglobin A1c (HbA1C), urea, creatinine, as well as lipid profile and liver function tests were analyzed. Upregulated level of IA-2 antibody was observed in 47.4 and 5.6% of T1DM and their relatives, respectively; however, the level was significantly higher in T1DM compared to T1DM first-degree relatives (p < 0.05). In addition, none of the T2DM patients nor healthy controls were positive for IA-2 autoantibody. There was not any significant correlation between anti-IA-2 levels and total daily dose of insulin and the biochemical and hematological parameters. It seems that the measurement of anti-IA-2 antibody has no value in prediction or management of T1DM. Further studies need to reveal the reason for high anti-IA-2 titer in some patients.

Administration of metrnl delays the onset of diabetes in non-obese diabetic mice.

Type 1 diabetes is a chronic metabolic disease characterized by hyperglycemia due to progressive destruction of pancreatic beta cells via autoimmune attack. Meteorin-like protein (metrnl) is a secreted protein homologous to the neurotrophin metrn and it is induced after exercise in the skeletal muscle. In our paper published previously, we showed that the serum level of metrnl was significantly correlated with the lipid profile, glucose profile and insulin resistance. In this experiment, we asked whether intravenous administration of metrnl could delay the onset of diabetes in non-obese diabetic (NOD) mice. 4-week-old NOD mice were injected intravenously with metrnl. Blood glucose levels were measured weekly. Insulitis scoring, intraperitoneal glucose tolerance test, adoptive T cell transfer, flow cytometry analysis and real-time PCR were performed to investigate the underlying mechanism. The results showed that intravenous administration of metrnl delayed the onset of diabetes in NOD mice. Histology of pancreas showed a decreased infiltration of leukocytes, which was in association with augmentation of regulatory T cells, suppression of autoreactive T cells and altered cytokine secretion. To sum up, the present study showed that intravenous administration of metrnl ameliorated islet lymphocyte infiltration and modulated immune cell responses, raising the possibility that it might be beneficial in improving islet function clinically.

Novel genetic risk factors influence progression of islet autoimmunity to type 1 diabetes

Type 1 diabetes arises from the autoimmune destruction of insulin-producing beta-cells of the pancreas, resulting in dependence on exogenously administered insulin to maintain glucose homeostasis. In this study, our aim was to identify genetic risk factors that contribute to progression from islet autoimmunity to clinical type 1 diabetes. We analyzed 6.8 million variants derived from whole genome sequencing of 160 islet autoantibody positive subjects, including 87 who had progressed to type 1 diabetes. The Cox proportional-hazard model for survival analysis was used to identify genetic variants associated with progression. We identified one novel region, 20p12.1 (TASP1; genome-wide P < 5 × 10–8) and three regions, 1q21.3 (MRPS21–PRPF3), 2p25.2 (NRIR), 3q22.1 (COL6A6), with suggestive evidence of association (P < 8.5 × 10–8) with progression from islet autoimmunity to type 1 diabetes. Once islet autoimmunity is initiated, functional mapping identified two critical pathways, response to viral infections and interferon signaling, as contributing to disease progression. These results provide evidence that genetic pathways involved in progression from islet autoimmunity differ from those pathways identified once disease has been established. These results support the need for further investigation of genetic risk factors that modulate initiation and progression of subclinical disease to inform efforts in development of novel strategies for prediction and intervention of type 1 diabetes.

Histone Deacetylase 3 Aggravates Type 1 Diabetes Mellitus by Inhibiting Lymphocyte Apoptosis Through the microRNA-296-5p/Bcl-xl Axis.

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by immune-mediated destruction of pancreatic beta-cells. Multiple microRNAs (miRNAs) have been implicated in T1DM pathogenesis. Although histone deacetylase 3 (HDAC3) has been reported to be involved in T1DM, the underlying mechanisms remain to be further elucidated. This study was designed to investigate the potential regulatory role of Hdac3 on T1DM progression. The expression of miR-296-5p and B-cell leukemia-XL (BCL-XL) was determined using RT-qPCR and Western blot assay in peripheral blood mononuclear cells (PBMCs) of patients with T1DM, tumor necrosis factor-α (TNF-α)- and cycloheximide (CHX)-induced cell model, and streptozotocin (STZ)-induced rat model. The binding affinity between miR-296-5p and Bcl-xl was verified by using dual-luciferase reporter gene assay, and the binding between Hdac3 and the promoter region of miR-296-5p was validated using chromatin immunoprecipitation assay. Western blot analysis and flow cytometry were conducted to assess the apoptotic events of lymphocytes. miR-296-5p expression was downregulated while BCL-XL expression was upregulated in PBMCs of patients with T1DM. An adverse correlation was identified between miR-296-5p and Bcl-xl in mouse TE15 B lymphocytes. Bcl-xl was further validated to be targeted and negatively regulated by miR-296-5p in 293 T cells. Hdac3 inhibited miR-296-5p expression by binding to its promoter region. The effects of overexpressed Hdac3 on lymphocyte apoptosis was counterweighed via downregulation of Bcl-xl or upregulation of miR-296-5p, the mechanism of which was further validated in a rat model of DM. Taken together, the Hdac3-mediated upregulation of Bcl-xl via inhibiting miR-296-5p promoter activity enhanced the anti-apoptotic capacity of lymphocytes to accelerate the occurrence of T1DM.

Dog leucocyte antigen (DLA) class II haplotypes and risk of canine diabetes mellitus in specific dog breeds

BackgroundCanine diabetes mellitus (DM) is a common endocrine disease in domestic dogs. A number of pathological mechanisms are thought to contribute to the aetiopathogenesis of relative or absolute insulin deficiency, including immune-mediated destruction of pancreatic beta cells. DM risk varies considerably between different dog breeds, suggesting that genetic factors are involved and contribute susceptibility or protection. Associations of particular dog leucocyte antigen (DLA) class II haplotypes with DM have been identified, but investigations to date have only considered all breeds pooled together. The aim of this study was to analyse an expanded data set so as to identify breed-specific diabetes-associated DLA haplotypes.MethodsThe 12 most highly represented breeds in the UK Canine Diabetes Register were selected for study. DLA-typing data from 646 diabetic dogs and 912 breed-matched non-diabetic controls were analysed to enable breed-specific analysis of the DLA. Dogs were genotyped for allelic variation at DLA-DRB1, -DQA1, -DQB1 loci using DNA sequence-based typing. Genotypes from all three loci were combined to reveal three-locus DLA class II haplotypes, which were evaluated for statistical associations with DM. This was performed for each breed individually and for all breeds pooled together.ResultsFive dog breeds were identified as having one or more DLA haplotype associated with DM susceptibility or protection. Four DM-associated haplotypes were identified in the Cocker Spaniel breed, of which one haplotype was shared with Border Terriers. In the three breeds known to be at highest risk of DM included in the study (Samoyed, Tibetan Terrier and Cairn Terrier), no DLA haplotypes were found to be associated with DM.ConclusionsNovel DLA associations with DM in specific dog breeds provide further evidence that immune response genes contribute susceptibility to this disease in some cases. It is also apparent that DLA may not be contributing obvious or strong risk for DM in some breeds, including the seven breeds analysed for which no associations were identified.

Lentivirus Mediated Pancreatic Beta-Cell-Specific Insulin Gene Therapy for STZ-Induced Diabetes

Autoimmune destruction of pancreatic beta cells is the characteristic feature of type 1 diabetes mellitus. Consequently, both short- and intermediate-acting insulin analogs are under development to compensate for the lack of endogenous insulin gene expression. Basal insulin is continuously released at low levels in response to hepatic glucose output, while post-prandial insulin is secreted in response to hyperglycemia following a meal. As an alternative to multiple daily injections of insulin, glucose-regulated insulin gene expression by gene therapy is under development to better endure postprandial glucose excursions. Controlled transcription and translation of proinsulin, presence of glucose-sensing machinery, prohormone convertase expression, and a regulated secretory pathway are the key features unique to pancreatic beta cells. To take advantage of these hallmarks, we generated a new lentiviral vector (LentiINS) with an insulin promoter driving expression of the proinsulin encoding cDNA to sustain pancreatic beta-cell-specific insulin gene expression. Intraperitoneal delivery of HIV-based LentiINS resulted in the lowering of fasting plasma glucose, improved glucose tolerance and prevented weight loss in streptozoticin (STZ)-induced diabetic Wistar rats. However, the combinatorial use of LentiINS and anti-inflammatory lentiviral vector (LentiVIP) gene therapy was required to increase serum insulin to a level sufficient to suppress non-fasting plasma glucose and diabetes-related inflammation.

Faecal microbiota transplantation halts progression of human new-onset type 1 diabetes in a randomised controlled trial

ObjectiveType 1 diabetes (T1D) is characterised by islet autoimmunity and beta cell destruction. A gut microbiota–immunological interplay is involved in the pathophysiology of T1D. We studied microbiota-mediated effects on disease...

Risk Factors of Type 1 Diabetes Mellitus in Children Attending Aswan University Hospital

Background: Type 1 diabetes (T1DM) is a chronic disease caused by immune-mediated destruction of insulin producing beta cells in the pancreas. The destruction of beta cells results in insulin insufficiency, and patients develop life-threatening hyperglycemia that clinically manifests with weight loss, polyuria, and polydipsia. Objective: This study aimed to search for disease prediction and disease prevention. Patients and methods: The present cross-sectional study was conducted at Aswan University Hospital. One hundred children with T1DM were included during the period from April to November 2018. The mean age of the included patients was 7.2 ± 4.3 years and the age at onset of the disease was 4.56 ± 2.9 years. 56% of the patients were males. Results: In our cohort, we found that, in terms of obstetric history, 76% of the mothers delivered by CS and 12% of them had history of preeclampsia. 13% had a history of gestational diabetes. On the other hand, 13% and 29% of the mothers had a history of infectious diseases and use of antibiotics, respectively. There were no statistically significant associations between age group and preeclampsia (p =0.33), gestational diabetes and use of insulin (p =0.67), infectious diseases (p =0.91), use of antibiotic (p =0.26), use of antihypertensives (p =0.22), and mode of delivery (p =0.067). Conclusion: In conclusion, Egyptian children with T1DM had wide range of genetics, environmental, maternal, and neonatal risk factors that may have contributed to the development of T1DM.

Characterization of plasma lipidomics in adolescent subjects with increased risk for type 1 diabetes in the DiPiS cohort

IntroductionType 1 diabetes (T1D) is caused by the destruction of pancreatic islet beta cells resulting in total loss of insulin production. Recent studies have suggested that the destruction may be interrelated to plasma lipids.ObjectivesSpecific lipids have previously been shown to be decreased in children who develop T1D before four years of age. Disturbances of plasma lipids prior to clinical diagnosis of diabetes, if true, may provide a novel way to improve prediction, and monitor disease progression.MethodsA lipidomic approach was utilized to analyze plasma from 67 healthy adolescent subjects (10–15 years of age) with or without islet autoantibodies but all with increased genetic risk for T1D. The study subjects were enrolled at birth in the Diabetes Prediction in Skåne (DiPiS) study and after 10–15 years of follow-up we performed the present cross-sectional analysis. HLA-DRB345, -DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 genotypes were determined using next generation sequencing. Lipidomic profiles were determined using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. Lipidomics data were analyzed according to genotype.ResultsVariation in levels of several specific phospholipid species were related to level of autoimmunity but not development of T1D. Five glycosylated ceramides were increased in insulin autoantibody (IAA) positive adolescent subjects compared to adolescent subjects without this autoantibody. Additionally, HLA genotypes seemed to influence levels of long chain triacylglycerol (TG).ConclusionLipidomic profiling of adolescent subjects in high risk of T1D may improve sub-phenotyping in this high risk population.

B cell helper T cells and type 1 diabetes

Type 1 diabetes is an autoimmune disease typically starting in childhood that culminates in the destruction of insulin‐producing beta cells in the pancreas. Although type 1 diabetes is considered to be a primarily T cell–mediated disease, B cells clearly participate in the autoimmune process, as autoantibodies recognizing pancreatic islet antigen commonly appear in circulation before the onset of the disease. T cells providing helper functions to B cells have recently been shown to be involved in the pathogenesis of a wide range of antibody‐associated immune disorders. These T cells include CXCR5‐positive follicular T helper (Tfh) cells, and a recently described closely related CXCR5‐negative subset coined peripheral T helper (Tph) cells. Here, we review the current state of knowledge on different B cell helper T cell subsets, focusing on their potential involvement in the development of type 1 diabetes.

Type 2 diabetes mellitus: pathogenesis and genetic diagnosis.

Type 2 diabetes mellitus (T2DM) is a heterogeneous condition that is related to both defective insulin secretion and peripheral insulin resistance. Beta cells are the major organ for secreting insulin hence, it is important to maintain an adequate beta-cell mass in response to various changes. Insulin resistance is a major cause of T2DM leads to elevated free fatty acid (FFA) levels which increases beta-cell mass and insulin secretion to compensate for insulin insensitivity. Chronic increase of plasma FFA levels results in disturbances in lipid metabolism, which contributes to decreased beta-cell function and lipotoxicity thus promoting T2DM. In the present review, we have discussed the process of beta-cell destruction, the role of genes in contributing to the fast increase in the progression of T2DM in detail. More than 130 variants in various T2DM susceptibility and candidate genes have been discovered to be associated with T2DM. Still, these variants elucidate only a small amount of total heritability of T2DM. Further, there is also an inventory of presently used therapeutic tools and a review of novel therapeutic approaches like incretin-based therapies or sodium-glucose transporter-2 inhibitors. Additionally, providing a concise but comprehensive update, this review will be essential to every clinician involved in the treatment of diabetes mellitus.

Automatically accounting for physical activity in insulin dosing for type 1 diabetes

Background and ObjectiveType 1 diabetes is a disease characterized by lifelong insulin administration to compensate for the autoimmune destruction of insulin-producing pancreatic beta-cells. Optimal insulin dosing presents a challenge for individuals with type 1 diabetes, as the amount of insulin needed for optimal blood glucose control depends on each subject's varying needs. In this context, physical activity represents one of the main factors altering insulin requirements and complicating treatment decisions. This work aims to develop and test in simulation a data-driven method to automatically incorporate physical activity into daily treatment decisions to optimize mealtime glycemic control in individuals with type 1 diabetes. MethodsWe leveraged glucose, insulin, meal and physical activity data collected from twenty-three individuals to develop a method that (i) tracks and quantifies the accumulated glycemic impact from daily physical activity in real-time, (ii) extracts an individualized routine physical activity profile, and (iii) adjusts insulin doses according to the prolonged changes in insulin needs due to deviations in daily physical activity in a personalized manner. We used the data replay simulation framework developed at the University of Virginia to “re-simulate” the clinical data and estimate the performances of the new decision support system for physical activity informed insulin dosing against standard insulin dosing. The paired t-test is used to compare the performances of dosing methods with p < 0.05 as the significance threshold. ResultsSimulation results show that, compared with standard dosing, the proposed physical-activity informed insulin dosing could result in significantly less time spent in hypoglycemia (15.3± 8% vs. 11.1± 4%, p = 0.007) and higher time spent in the target glycemic range (66.1± 11.7% vs. 69.6± 12.2%, p < 0.01) and no significant difference in the time spent above the target range(26.6± 1.4 vs. 27.4± 0.1, p = 0.5). ConclusionsIntegrating daily physical activity, as measured by the step count, into insulin dose calculations has the potential to improve blood glucose control in daily life with type 1 diabetes.

Retro-inverso D-peptides as a novel targeted immunotherapy for Type 1 diabetes

Over the past four decades, the number of people with Type 1 Diabetes (T1D) has increased by 4% per year, making it an important public health challenge. Currently, no curative therapy exists for T1D and the only available treatment is insulin replacement. HLA-DQ8 has been shown to present antigenic islet peptides driving the activation of CD4+ T-cells in T1D patients. Specifically, the insulin peptide InsB:9-23 activates self-reactive CD4+ T-cells, causing pancreatic beta cell destruction. The aim of the current study was to identify retro-inverso-d-amino acid based peptides (RI-D-peptides) that can suppress T-cell activation by blocking the presentation of InsB:9-23 peptide within HLA-DQ8 pocket. We identified a RI-D-peptide (RI-EXT) that inhibited InsB:9-23 binding to recombinant HLA-DQ8 molecule, as well as its binding to DQ8 expressed on human B-cells. RI-EXT prevented T-cell activation in a cellular antigen presentation assay containing human DQ8 cells loaded with InsB:9-23 peptide and murine T-cells expressing a human T-cell receptor specific for the InsB:9-23–DQ8 complex. Moreover, RI-EXT blocked T-cell activation by InsB:9-23 in a humanized DQ8 mice both ex vivo and in vivo, as shown by decreased production of IL-2 and IFN-γ and reduced lymphocyte proliferation. Interestingly, RI-EXT also blocked lymphocyte activation and proliferation by InsB:9-23 in PBMCs isolated from recent onset DQ8-T1D patients. In summary, we discovered a RI-D-peptide that blocks InsB:9-23 binding to HLA-DQ8 and its presentation to T-cells in T1D. These findings set the stage for using our approach as a novel therapy for patients with T1D and potentially other autoimmune diseases.

Hybrid Polydimethylsiloxane Bioscaffold-Intravascular Catheter for Cellular Therapies.

Type-1 diabetes (T1D) is caused by immune-mediated destruction of insulin-producing beta-cells, resulting in insulin deficiency and hyperglycemia. Islet transplantation is a potential treatment for T1D, but clinical implementation is hampered by islet availability and poor islet survival post-transplantation. To overcome these issues, we developed an intravascular multiside hole catheter with an interior polydimethylsiloxane (PDMS) bioscaffold capable of housing a cellular cargo. We used computational fluid dynamics to determine an optimized catheter design, which we then fabricated. Using our hybrid PDMS bioscaffold-intravascular catheter, we demonstrated that this platform can successfully maintain in vitro islet function and viability.

Presumption of innocence for beta cells: why are they vulnerable autoimmune targets in type 1 diabetes?

It is increasingly appreciated that the pathogenic mechanisms of type 1 diabetes involve both the autoimmune aggressors and their beta cell targets, which engage in a conflicting dialogue within and possibly outside the pancreas. Indeed, autoimmune CD8+ T cells, which are the final mediators of beta cell destruction, circulate at similar frequencies in type 1 diabetic and healthy individuals. Hence a universal state of 'benign' islet autoimmunity exists, and we hypothesise that its progression to type 1 diabetes may at least partially rely on a higher vulnerability of beta cells, which play a key, active role in disease development and/or amplification. We posit that this autoimmune vulnerability is rooted in some features of beta cell biology: the stress imposed by the high rate of production of insulin and other granule proteins, their dense vascularisation and the secretion of their products directly into the bloodstream. Gene variants that may predispose individuals to this vulnerability have been identified, e.g. MDA5, TYK2, PTPN2. They interact with environmental cues, such as viral infections, that may drive this genetic potential towards exacerbated local inflammation and progressive beta cell loss. On top of this, beta cells set up compensatory responses, such as the unfolded protein response, that become deleterious in the long term. The relative contribution of immune and beta cell drivers may vary and phenotypic subtypes (endotypes) are likely to exist. This dual view argues for the use of circulating biomarkers of both autoimmunity and beta cell stress for disease staging, and for the implementation of both immunomodulatory and beta cell-protective therapeutic strategies. Graphical abstract.

Angiotensin-converting enzyme 2 influences pancreatic and renal function in diabetic mice

AbstractType 1 diabetes is a T-cell mediated autoimmune disease characterized by pancreatic beta cells destruction. Angiotensin-converting enzyme 2 (ACE2), a component of renin–angiotensin system (RAS) has been identified in pancreas from type 2 diabetic mice and its overexpression prevents beta cell dysfunction. We studied the effect of ACE2 deletion on pancreatic and renal function in the nonobese diabetic mice, a model that mimics type 1 diabetes. ACE2-deficient NOD mice and the respective controls were generated. Pancreas function and immunohistochemistry studies were performed. Renal function and RAS gene expression were also analyzed. Renal proximal tubular cells were obtained from these animals to dissect the effect of ACE2 deficiency in these cells. In NOD mice, ACE2 deletion significantly worsened glucose homeostasis, decreased islet insulin content, increased beta cell oxidative stress, and RIPK1-positive islets as compared with control mice. Angiotensin-converting enzyme and angiotensin II type 1 receptor (AT1R) were also increased in ACE2-deficient mice. In kidneys of 30-day diabetic mice, ACE2 deletion decreased podocyte number within the glomeruli, and altered renal RAS gene expression in tubules. ACE2 deletion influenced the expression of fibrosis-related genes in isolated primary renal proximal tubular cells before diabetes onset in NOD mice. Our findings suggest that ACE2 deletion may have a deleterious impact on beta cell and renal function, by promoting oxidative stress and increasing necroptosis mediators. In addition, this effect is accompanied by RAS alterations in both pancreas and renal proximal tubular cells, indicating that ACE2 may exert a renopancreatic protective effect on type 1 diabetes, which is activated before diabetes starts.This study examined the contribution of ACE2 in diabetes onset and the role of ACE2 in the progression of diabetic nephropathy in NOD mouse. ACE2 loss leads to an impaired glucose and insulin homeostasis, RAS activation, increase in oxidative stress, and RIPK1 within the pancreas. In the kidney, ACE2 deletion induced podocyte loss, RAS modulation, and renal fibrosis activation in an early phase of diabetes.