Islet Beta Cells Research Articles

Quantitative analysis of islet prohormone convertase 1/3 expression in human pancreas donors with diabetes.

Islet prohormone-processing enzymes convert peptide hormone precursors to mature hormones. Defective beta cell prohormone processing and the release of incompletely processed peptide hormones are observed prior to the onset of diabetes, yet molecular mechanisms underlying impaired prohormone processing during the development of diabetes remains largely unknown. Previous studies have shown that prohormone convertase 1/3 (PC1/3) protein and mRNA expression levels are reduced in whole islets from donors with type 1 diabetes, although whether PC1/3-mediated prohormone processing in alpha and beta cells is disrupted in type 1 diabetes remained to be explored. Herein, we aimed to analyse the expression of PC1/3 in islets from non-diabetic donors, autoantibody-positive donors and donors diagnosed with type 1 diabetes or type 2 diabetes. Immunostaining and high-dimensional image analysis were performed on pancreatic sections from a cross-sectional cohort of 54 donors obtained from the Network for Pancreatic Organ Donors with Diabetes (nPOD) repository, to evaluate PC1/3 expression patterns in islet alpha, beta and delta cells at different stages of diabetes. Alpha and beta cell morphology were altered in donors with type 1 diabetes, including decreased alpha and beta cell size. As expected, the insulin-positive and PC1/3-positive areas in the islets were both reduced, and this was accompanied by a reduced percentage of PC1/3-positive and insulin-positive/PC1/3-positive cells in islets. PC1/3 and insulin co-localisation was also reduced. The glucagon-positive area, as well as the percentage of glucagon-positive and glucagon-positive/PC1/3-positive cells in islets, was increased. PC1/3 and glucagon co-localisation was also increased in donors with type 1 diabetes. The somatostatin-positive cell area and somatostatin staining intensity were elevated in islets from donors with recent-onset type 1 diabetes. Our high-resolution histomorphological analysis of human pancreatic islets from donors with and without diabetes has uncovered details of the cellular origin of islet prohormone peptide processing defects. Reduced beta cell PC1/3 and increased alpha cell PC1/3 in islets from donors with type 1 diabetes pinpointed the functional deterioration of beta cells and the concomitant potential increase in PC1/3 usage for prohormone processing in alpha cells during the pathogenesis of type 1 diabetes. Our finding of PC1/3 loss in beta cells may inform the discovery of new prohormone biomarkers as indicators of beta cell dysfunction, and the finding of elevated PC1/3 expression in alpha cells may encourage the design of therapeutic targets via leveraging alpha cell adaptation in diabetes.

7815 Pembrolizumab-Induced Autoimmune Hypophysitis with “Isolated” ACTH Deficiency: Need for Heightened Awareness and Action Among Medical Fraternity

Abstract Disclosure: S. Shankar: None. S.S. Sundar: None. M.S. Vaishnav: None. L. Lekkala: None. K. Thummala: None. S. Srikanta: None. T. Deepak: None. R.B. Vijay: None. K. Muniraj: None. V. Nath: None. C. Siddlingappa: None. P. Ravikumar: None. M.D. Chitra: None. Introduction: Autoimmune hypophysitis caused by immune checkpoint inhibitors [ICIs; anti-CTLA-4 (Ipilimumab alone 7.9%), anti-PD-1 (Pembrolizumab alone 1.7%; nivolumab alone 0%)] are being increasingly documented, with anterior hypopituitarism affecting corticotrophs more commonly than thyrotrophs and gonadotrophs (large time span of onset; different recovery patterns). Clinical Case 2021 Sep Age 65 years (type 2 diabetes, hypertension). Renal Cell Carcinoma S/P radical nephrectomy. 2023 Jul PET-CT= Metastatic pleuropulmonary nodules. Four admissions to Specialist Oncology Hospital [Four 2 weekly cycles of Inj Pembrolizumab 200 mg (with Tab Axitinib 10 mg/day)]. After first cycle: progressive fatigue, body aches, drowsiness. S Sodium= Pre-pembrolizumab= 137 mEq/L (135-145); Post-pembrolizumab= 124, 134, 132, 124; T3= 1.63 to 0.60 to 1.24 to 1.35 ng/mL (0.97-1.69); T4= 6.83 to 4.93 to 10.44 to 11.44 mcg/dL (5.53-11); TSH= 10.46 to 6.28 to 5.39 to 9.48 mIU/mL (0.46-4.68); S Cortisol 8 am= 1.54 mcg/dL (5-25); S Potassium= 4.59 mEq/dL (3.5-5.1)]. One episode of loss of consciousness; EEG= abnormal; MRI Brain= normal. During every hospital admission, oncology, medical, endocrinology and nephrology teams attributed the same to “illness” (no specific diagnosis) and provided symptomatic treatment (IV 3% saline, tolvaptan and sodium bicarbonate tablets).2023 Nov Medicine: Very severe nausea, anorexia, generalised weakness, myalgia, hiccoughs, and inability to walk. Frustrated family members sought admission in “new” General Hospital. S Sodium= 119, 120; S Potassium= 4.8; S Creatinine= 1.67 mg/dL (0.7-1.3); S Uric acid= 4.5 mg/dL (4.40-7.60); Urine spot Sodium= 84 mmol/L; ESR= 144 mm. Endocrinology: S Cortisol 8 am= 0.09 mcg/dL;S Cortisol post 250 mcg Inj Synacthen= 3.76 (>20);Plasma ACTH= 5.4 pg/ml (9-52). S T3= 1.35; S T4= 11.44; S TSH= 9.48; LH= 3.61mIU/mL (1.5-9.3); FSH= 1.4mIU/mL (1.4-18.1); PRL= 30.1 (2.6-13.3); Testosterone total= 314 ng/dL (241-827); TPO antibodies negative. MRI-Pituitary: Partial empty sella; infundibulum neurohypophysis normal; mild asymmetric enhancement (5.5 mm) left cavernous sinus. Treatment: Tab Hydrocortisone 25 mg/day, with complete clinical and biochemical response [Suggestion of gonadotroph dysfunction and partial recovery of thyrotrope dysfunction/ injury. Hence, not on thyroxine replacement]. Clinical Lessons: Mechanisms for differential cellular vulnerability for ICI induced autoimmune pathologies [thyroid (destructive versus stimulatory), islet beta cells, adrenal cortical cells, various anterior pituitary cells (corticotrophs vs thyrotrophs and gonadotrophs] need elucidation. Specific molecular and cellular immunopathogenic pathways in different autoimmune endocrinopathies appear distinct and disparate. Presentation: 6/2/2024

8343 The Role Of Pancreatic Nerve Activity On The Development Of Beta Cell Dysfunction With The Macrophage-Beta Cell Interaction

Abstract Disclosure: J. Yu: None. Y. Wang: None. L. Sha: None. Islet inflammation is a vital factor to the beta cell dysfunction which is driven by inflammatory cytokines TNF-α and IL-1β released by resident macrophages. Pancreatic nerve innervates islet function and our previous study suggested that pancreatic nerve activity might involved in the development of pancreatic beta cell dysfunction. However, it is not known whether pancreatic nerve activity modulates macrophage activity and contributes to the macrophage - beta cell interaction. The aim of our study was to investigate the role of nerve activity on it and the possible mechanism. Methods: Sprague Dawley Rats and high fat diet-induced obese rates were used. An intrapancreatic nerve truck with its intact innervated pancreatic islets were used for the study. The nerve activity was evoked with electric nerve stimulation and insulin and ATP released by beta cells, TNF-α released by macrophages, and IL-1β released mainly by macrophages were measured with nerve activation. Results: Insulin secretion was induced significantly with the nerve activation (8 Hz). With nerve activation, ATP level was significantly increased by 25.5 ± 11.7%. The increased releases of insulin and ATP were abolished with cholinergic M receptor blocker atropine. With nerve activation, TNF-α and IL-1β levels were increased by 25.3±7.6% and 51.8±11.7%, respectively (p<0.05). Interestingly, the increases of TNF-α and IL-1β with nerve activation were also blocked by atropine. Since it is known that acetylcholine does not induce pro-inflammatory cytokine release in macrophages, we suspected that the nerve activity induced TNF-α and IL-1β releases were indirect. ATP is likely a candidate for the indirect effect as receptors. With applying Suramin, a ATP receptor blocker, nerve activation increased TNF-α release was inhibited significantly and IL-1β release was trended to inhibited. atropine, an M receptor blocker, compared with the Control group, decreased by 88.0±3.7% and 63.1±19.6%, respectively (p< 0.01). In obese rats, nerve activation increased TNF-α and IL-1β content by 68.1 ± 22.6% and 39.7 ± 7.4%, respectively, and suramin significantly inhibited the nerve activation induced increase of TNF-α release and trended to inhibit IL-1β release. Conclusion: Our results suggested that the pancreatic nerve activity contribute to the macrophage-beta cell interaction in the development of beta cells dysfunction by enhancing ATP release from islet beta cells. Presentation: 6/3/2024

8010 Potent MSB-61 as Type 1 Diabetes (T1D) therapy: mechanism of action in insulin secretion

Abstract Disclosure: N. Ajmal: None. M. Bogart: None. K. Corbin: None. P. Khan: None. M. Shafqat: None. S. Bergmeier: None. G. Gu: None. X. Tong: None. C.S. Nunemaker: None. Type 1 diabetes (T1D) is a chronic autoimmune disorder caused by proinflammatory cytokines (Interleukin 1-beta; IL1-β, Tumor Necrosis Factor-alpha; TNF-α, and Interferon-gamma; IFN-ϒ) from immune cells that destroy insulin-producing beta cells in pancreatic islets and lead to hyperglycemia. The development of possible treatments to cure T1D is needed besides intensive insulin therapy that does not halt disease progression. We have identified a small molecule called MSB-61 that can protect islet cells from endoplasmic reticulum stressors (66% protection) and cytokines (33% protection) as measured by propidium iodide in islets isolated from mice using 50uM MSB-61. Importantly, we observed large increases in insulin secretion during overnight exposure to 50uM MSB-61. Insulin secretion began to increase in response to MSB-61 at ∼4h, reaching a plateau at ∼8h of greater than 4-fold insulin release compared to controls. The Kegg pathway analysis of RNA-seq data on MSB-61 suggested that multiple genes upregulated by MSB-61 are involved in insulin secretion through an amplifying pathway that includes cAMP/PKA and Pi3k/Akt signaling cascades. Based on RNA sequencing data, this study aimed to test MSB-61 for identifying pathway by which it potentiates insulin secretion. Islets from CD-1 mice and mouse insulinoma Min-6 cell lines were used to test amplifying pathways by using cAMP/PKA and Pi3k/Akt analogs and antagonists with and without MSB-61, and overnight insulin secretion and insulin content will be measured by enzyme-linked immunosorbent assay (ELISA). MSB-61 showed no potential effects on insulin secretion when tested for Pi3k/Akt pathway in the presence of analogs and antagonists such as 740-Y-P and wortmannin. It further suggests MSB-61 might potentiate insulin secretion through the cAMP/PKA pathway, which is still under investigation. RNA sequencing analysis of mouse islets showed several genes that belong to Ras family member-2 and have GTPase activity. Genes with GTPase activity will be further investigated to help identify if MSB-61 stimulates insulin secretion through an amplifying pathway involving the cAMP/PKA downstream signaling cascade. Identifying the mechanism of action and signaling pathway by which MSB-61 potentiates insulin secretion will open new ways of identifying T1D therapeutic interventions that would help replace standard insulin therapy. Presentation: 6/3/2024

9185 Pembrolizumab-Induced New-Onset Type 1 Diabetes Mellitus: A Case Report

Abstract Disclosure: D. Teng: None. T.L. Connelly: None. M. Ahmad: None. R. Saeed: None. Introduction: Immune checkpoint inhibitors are becoming essential in the treatment of various cancers. Pembrolizumab is a monoclonal antibody that binds PD-1 receptors, thereby enabling an anti-tumor response by preventing T-cell suppression. Common side effects associated with pembrolizumab include thyroid disorders, hepatitis, pneumonitis, and acute kidney injury, among others. We describe an interesting case of a woman presenting with diabetic ketoacidosis (DKA) in the setting of pembrolizumab-associated new-onset type 1 diabetes mellitus, which was reported at 0.1% during initial clinical trials but is now being increasingly recognized as a complication of immune checkpoint therapy. Case Description: The patient is a 70-year-old female with past medical history notable for stage IIIA vulvar squamous cell carcinoma initially diagnosed and treated in 2017, with recurrence in 2022 and in 2023, at which point pembrolizumab therapy was initiated. Approximately one month after her first dose, the patient presented to the emergency department with palpitations, nausea, non-bloody vomiting, polydipsia, and non-bloody diarrhea. On arrival, the patient’s vital signs were as follows: 97.2 °F, BP 128/74 mmHg, heart rate 80 bpm, respiratory rate 18 per minute, and SpO2 100% on room air. No acute findings were noted on physical exam. Initial blood work was notable for: pH 7.146, lactate 2.4 mmol/L, bicarbonate 8 mmol/L, anion gap 37 mmol/L, creatinine 1.59 mg/dL, glucose 563 mg/dL, C-peptide 0.16 ng/mL, HbA1c 6.9%, and WBC 18.8 B/L with neutrophilic predominance. Urinalysis was notable for 4+ glucose and 4+ ketones. The patient was admitted to the progressive care unit and DKA protocol was initiated including the administration of IV fluids, insulin infusion, and electrolyte replacement. Additional blood work was unrevealing, including insulin autoantibodies <0.4 U/mL, negative islet cell IgG cytoplasmic autoantibodies, and negative anti-GAD65 antibodies. The patient was eventually discharged with outpatient Endocrinology follow-up. Discussion: Immunotherapy is quickly redefining the standard of care in the treatment of several types of malignancies through the leveraging of the body’s immune defense apparatus. Pembrolizumab prevents the deactivation of T-cells via the PD-1/PD-L1 pathway. Unfortunately, this also predisposes non-cancerous cells to autoimmune destruction by these T-cells. It is proposed that such is the mechanism by which pancreatic beta islet cells are destroyed in the setting of pembrolizumab use, thereby resulting in a rapid reduction in insulin production capability. New-onset type 1 diabetes complicated by DKA is potentially life-threatening, and so we believe this case highlights the need for both pre-treatment counseling as well as follow-up screening following initiation of pembrolizumab therapy. Presentation: 6/2/2024

Comparative Ability of Various Immunosuppressants as Adjuvants on the Activity of T1D Vaccine

Background: Type 1 diabetes (T1D) is an autoimmune disorder characterised by the destruction of insulin-producing beta cells in the pancreatic islets, resulting from a breakdown in immunological tolerance. Currently, T1D treatment primarily relies on insulin replacement or immunosuppressive therapies. However, these approaches often have significant drawbacks, including adverse effects, high costs, and limited long-term efficacy. Consequently, there is a pressing need for innovative immunotherapeutic strategies capable of inducing antigen-specific tolerance and protecting beta cells from autoimmune destruction. Among the various antigens, β-cell antigens like 65 kDa glutamic acid decarboxylase (GAD65) have been explored as vaccine candidates for T1D. Despite their potential, their effectiveness in humans remains modest, necessitating the use of appropriate adjuvants to enhance the vaccine’s protective effects. Methods: In this study, we evaluated the therapeutic potential of kynurenine (KYN), dexamethasone (DXMS), tacrolimus (FK506), and aluminium hydroxide (Alum) in combination with the GAD65 phage vaccine as adjuvants. Results: Our findings demonstrate that KYN, when used in conjunction with the GAD65 vaccine, significantly enhances the vaccine’s immunosuppressive effects. Compared to dexamethasone, FK506, and Alum adjuvants, KYN more effectively reduced the incidence and delayed the onset of T1D, preserved β-cell function, and promoted the induction of regulatory T cells and antigen-specific tolerance. These results suggest that KYN combined with vaccines could offer superior preventive and therapeutic benefits for T1D compared to existing treatments. Additionally, we investigated the dose-dependent effects of the GAD65 vaccine by including a low-dose group in our study. The results indicated that reducing the vaccine dose below 1010 plaque-forming units (pfu) did not confer any protective advantage or therapeutic benefit in combination with KYN. This finding underscores that 1010 pfu is the minimum effective dose for the GAD65 vaccine in achieving a protective response. In conclusion, KYN shows considerable promise as an adjuvant for the GAD65 vaccine in T1D therapy, potentially offering a more effective and durable treatment option than current immunosuppressive strategies.

Targeting the Autoreactive CD8 T-cell Receptor in Type 1 Diabetes: Insights from scRNA-seq for Immunotherapy

Type 1 Diabetes (T1D) is an autoimmune disease characterized by the attack and destruction of Pancreatic islet beta cells by T cells. Understanding the role of T-cell receptor (TCR) in the development of T1D is of paramount importance. This study employs single-cell RNA sequencing (scRNA-seq) to delve into the mechanistic actions and potential therapeutic applications of autoreactive stem cell-like CD8 TCR in T1D. By retrieving T-cell data from non-obese diabetic (NOD) mice via the GEO database, it was revealed that CD8+ T cells are the predominant T-cell subset in the pancreatic tissue of T1D mice, along with the identification of T-cell marker genes closely associated with T1D. Moreover, the gene TRAJ23 exhibits a preference for T1D, and its knockout alleviates T1D symptoms and adverse reactions in NOD mice. Additionally, engineered TCR-T cells demonstrate significant cytotoxicity towards β cells in T1D.

The use of Oral Anti-Diabetic Medications in Diabetes Mellitus type 1: An Educational Article and Expert Opinion

Diabetes mellitus type 1 is lifelong condition resulting from failure of production of insulin because of the loss of pancreatic islet beta-cells because of autoimmune damage. Patients with this type of diabetes need lifelong treatment with insulin to remain alive. Poor diabetic control which predisposes to a variety of complications is not uncommon in patients treated with insulin alone. Therefore, the use of medications that can possibly enhance the therapeutic effect of insulin and reduce the risk of diabetic complications has been considered. Oral anti-diabetics including acarbose, an inhibitor of intestinal α-glucosidase, metformin, a biguanide, sulfonylureas including glipizide, and sitagliptin, an inhibitor of dipeptidyl peptidase 4 (DPP-4) are primarily used for the treatment of non-insulin dependent diabetes (Type 2). The aim of this paper is to provide an overview of the use of oral anti-diabetics in the treatment of insulin dependent diabetes (Type 1). Expert opinion: The current evidence-based expert opinion recommends the judicious use of oral anti-diabetics especially acarbose and metformin in the treatment of unsatisfactorily controlled insulin dependent diabetes type 1. These medications can help in improving diabetic control through reducing glucose levels after meals, and can contribute to lowering the levels of glycosylated hemoglobin (HbA1c). The use of these oral anti-diabetics can also help in reducing insulin requirement.

A capsule-based scaffold incorporating decellularized extracellular matrix and curcumin for islet beta cell therapy in type 1 diabetes mellitus

The transplantation of islet beta cells offers an alternative to heterotopic islet transplantation for treating type 1 diabetes mellitus (T1DM). However, the use of systemic immunosuppressive drugs in islet transplantation poses significant risks to the body. To address this issue, we constructed an encapsulated hybrid scaffold loaded with islet beta cells. This article focuses on the preparation of the encapsulated structure using 3D printing, which incorporates porcine pancreas decellularized extracellular matrix (dECM) to the core scaffold. The improved decellularization method successfully preserved a substantial proportion of protein (such as Collagen I and Laminins) architecture and glycosaminoglycans in the dECM hydrogel, while effectively removing most of the DNA. The inclusion of dECM enhanced the physical and chemical properties of the scaffold, resulting in a porosity of 83.62% ± 1.09% and a tensile stress of 1.85 ± 0.16 MPa. In teams of biological activity, dECM demonstrated enhanced proliferation, differentiation, and expression of transcription factors such as Ki67, PDX1, and NKX6.1, leading to improved insulin secretion function in MIN-6 pancreatic beta cells. In the glucose-stimulated insulin secretion experiment on day 21, the maximum insulin secretion from the encapsulated structure reached 1.96 ± 0.08 mIU ml-1, representing a 44% increase compared to the control group. Furthermore, conventional capsule scaffolds leaverage the compatibility of natural biomaterials with macrophages to mitigate immune rejection. Here, incorporating curcumin into the capsule scaffold significantly reduced the secretion of pro-inflammatory cytokine (IL-1β, IL-6, TNF-α, IFN-γ) secretion by RAW264.7 macrophages and T cells in T1DM mice. This approach protected pancreatic islet cells against immune cell infiltration mediated by inflammatory factors and prevented insulitis. Overall, the encapsulated scaffold developed in this study shows promise as a natural platform for clinical treatment of T1DM.

Abstract PR-05: Endocrine beta-cell stress promotes pancreatic ductal adenocarcinoma through endocrine-exocrine cell crosstalk

Abstract For a long time, the pancreas was thought to have separate cellular compartments that functioned distinctly from one another. The endocrine pancreas (islets of Langerhans) regulates glucose homeostasis, while the exocrine pancreas (acini and ducts) produces and secretes digestive enzymes. However, it has recently become clear that the endocrine and exocrine compartments communicate with one another, and dysfunction in one leads to dysfunction in the other, resulting in diabetes or pancreatitis. However, whether and how the endocrine pancreas drives the development of pancreatic ductal adenocarcinoma (PDAC), an exocrine tumor, remains unresolved. Strikingly, we found that genetic ablation of insulin-producing islet beta (β) cells (Akita) in a faithful Kras/Trp53-driven PDAC model (KPC: Kras LSL-G12D /+; Trp 53172 /+; Pdx1-Cre) suppressed PDAC progression. Conversely, obesity-induced β cell hormone dysregulation promoted Kras-driven PDAC development. Single-cell RNA sequencing (scRNA-seq) analysis of wild-type and obese mice (high-fat diet-fed and leptin-deficient (Lep ob/ob )) revealed increased expression of the peptide hormone cholecystokinin (CCK) in a subset of β cells concordant with increasing obesity, and transgenic β cell overexpression of CCK was sufficient to promote exocrine tumorigenesis in KC mice. Combined in silico (pseudotime (TrajectoryNET) and archetypal (AANet) analysis) and experimental (CreER) lineage tracing demonstrated that CCK-expressing β cells originated from a pre-existing immature β cell population (virgin β cells). Grainger causality analysis of transcriptional networks uncovered a stress-induced JNK-cJun pathway that promotes CCK expression β cells, which we confirmed using JNK inhibitors in β cell models. Together, our findings identify cellular and molecular mechanisms of β cell adaptation to obesity that contribute to obesity-driven pancreatic cancer. Furthermore, we define a critical role for endocrine-exocrine signaling in PDAC progression and stress-induced β cell pathways which could be leveraged to target the endocrine pancreas to subvert exocrine tumorigenesis. Citation Format: Cathy Garcia, Aarthi Venkat, Daniel McQuaid, Sherry Agabiti, Alex Tong, Rebecca Cardone, Richard Kibbey, Smita Krishnaswamy, Mandar Muzumdar. Endocrine beta-cell stress promotes pancreatic ductal adenocarcinoma through endocrine-exocrine cell crosstalk [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-05.

Long-term TNF-alpha therapy for preserving beta cell function in new onset type 1 diabetes: a case report

BackgroundType 1 diabetes mellitus (T1D) is an autoimmune disease caused by destruction of pancreatic islet beta-cells. There is significant residual beta-cell function, measured through circulating C-peptide, present at the time of T1D diagnosis but this subsequently decreases with time. Higher residual beta-cell function at diagnosis associates with better glycaemic control and less glucose variability, and later in the disease course with less hypoglycaemia, lower glucose variability and fewer microvascular complications. There is therefore value in preserving residual beta cell function in new onset T1D Immunotherapeutic agents can protect residual beta-cell function in type 1 diabetes. However, clinical trials of such agents, whilst demonstrating C-peptide preservation in short term studies, have yet to be taken forward into routine clinical care due to concerns around safety and long-term efficacy. Here we report the case of a gentleman with newly diagnosed T1D whose glycaemic control and insulin requirement improved whilst on a five year infusion programme of infliximab, a monoclonal antibody against TNF-alpha, for colitis.Case presentationA 52-year-old White Caucasian man was diagnosed with T1D in August 2018. Glucose was 25.6 mmol/L, HbA1c was 98mmol/mol and GAD antibodies were strongly positive. HbA1c marginally improved to 91mmol/mol following initiation of insulin detemir 5 units at night and 1:10 g of insulin aspart (November 2018). In June 2019, he developed rectal bleeding and abdominal pain. Following colonoscopy, he was diagnosed with “indeterminate colitis” and commenced on 6-weekly infusions of 400-450 mg infliximab. Thus far, he has received 32 doses and achieved colitis remission. Following infliximab initiation there was increased frequency of mild-moderate hypoglycaemia and he was gradually weaned off and discontinued detemir in June 2020. Since then, HbA1c improved from 57mmol/mol in August 2019 to 52mmol/mol in April 2022, remaining stable at 51mmol/mol. His most recent HbA1c is 54mmol/mol in February 2024. His c-peptide was 550pmol/L in October 2022 and 442pmol/L in February 2024, suggesting well-preserved beta-cell function almost 6 years post-diagnosis.ConclusionsOur patient’s improvement in glycaemic control can be explained by immunomodulation and C peptide preservation from infliximab. With the growing focus on type 1 diabetes disease modulation and working towards an ‘insulin free T1D’, our findings strengthen the evidence base for the repurposing of and long-term treatment with anti-TNF-α agents to preserve beta-cell function in new onset T1D.

Drug Repurposing for Thioredoxin Interacting Protein Through Molecular Networking, Pharmacophore Modelling, and Molecular Docking Approaches

Background: Diabetes Mellitus (DM) has emerged as one of the major causes behind global all-cause mortality between the age group of 20-79 years. Thioredoxin Interacting Protein (TXNIP) is a naturally occurring protein that primarily acts by binding to TRX protein, thereby inhibiting its ability to maintain the cellular reduced environment and subsequent oxidative stress, which leads to dysfunctional insulin production and pancreatic islet beta cell apoptosis. Objective: By inhibiting the levels of TXNIP, a search for new molecules was carried out by employing an in-silico approach. Methods: Molecular networking study was carried out using Cytoscape, wherein previously FDAapproved drugs were screened to check their ability to interact with TXNIP. This provided 14 drug molecules, which along with 11 previously obtained drug molecules that inhibit TXNIP, were subjected to pharmacophore generation. A pharmacophore was generated using the PharmaGist web server, which when visualised showed two hydrogen bond acceptors and one aromatic ring. Based on the generated pharmacophore model, we carried out virtual screening using ZINCPharmer. A total of 116 HITs were generated based on this pharmacophore model. We then subjected the 116 molecules to Molecular Docking against TXNIP (PDB: 4GEI) by using PyRx and the standard molecules, metformin and rosiglitazone. Results: Compared to the standard, we found 10 molecules that had a better binding affinity towards TXNIP. These 10 molecules were further taken for ADMET studies. From this, all 10 compounds showed good significant ADMET properties. Conclusion: From the preliminary studies, these 10 molecules showed good activity in the reversal of diabetes mellitus by reducing the levels of TXNIP.

Structural and biochemical analysis of highly similar HLA-B allotypes differentially associated with type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease involving T cell-mediated destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans. CD8+ T cells, responding to beta cell peptides presented by class I major histocompatibility complex (MHC) molecules, are important effectors leading to beta cell elimination. Human leukocyte antigen (HLA) B*39:06, B*39:01, and B*38:01 are closely related class I MHC allotypes that nonetheless show differential association with T1D. HLA-B*39:06 is the most predisposing of all HLA class I molecules and is associated with early age at disease onset. B*39:01 is also associated with susceptibility to T1D, but to a lesser extent, though differing from B*39:06 by only two amino acids. HLA-B*38:01, in contrast, is associated with protection from the disease. Upon identifying a peptide that binds to both HLA-B*39:06 and B*39:01, we determined the respective X-ray structures of the two allotypes presenting this peptide to 1.7 Å resolution. The peptide residues available for T cell receptor contact and those serving as anchors were identified. Analysis of the F pocket of HLA-B*39:06 and B*39:01 provided an explanation for the distinct peptide C-terminus preferences of the two allotypes. Structure-based modeling of the protective HLA-B*38:01 suggested a potential reason for its peptide preferences and its reduced propensity to present 8-mer peptides compared to B*39:06. Notably, the three allotypes showed differential binding to peptides derived from beta cell autoantigens. Taken together, our findings should facilitate identification of disease-relevant candidate T cell epitopes and structure-guided therapeutics to interfere with peptide binding.

Exploring pancreatic beta-cell subgroups and their connectivity.

Functional pancreatic islet beta cells are essential to ensure glucose homeostasis across species from zebrafish to humans. These cells show significant heterogeneity, and emerging studies have revealed that connectivity across a hierarchical network is required for normal insulin release. Here, we discuss current thinking and areas of debate around intra-islet connectivity, cellular hierarchies and potential "controlling" beta-cell populations. We focus on methodologies, including comparisons of different cell preparations as well as in vitro and in vivo approaches to imaging and controlling the activity of human and rodent islet preparations. We also discuss the analytical approaches that can be applied to live-cell data to identify and study critical subgroups of cells with a disproportionate role in control Ca2+ dynamics and thus insulin secretion (such as "first responders", "leaders" and "hubs", as defined by Ca2+ responses to glucose stimulation). Possible mechanisms by which this hierarchy is achieved, its physiological relevance and how its loss may contribute to islet failure in diabetes mellitus are also considered. A glossary of terms and links to computational resources are provided.

Mechanisms of spinophilin-dependent pancreas dysregulation in obesity.

Spinophilin is an F-actin binding and protein phosphatase 1 (PP1) targeting protein that acts as a scaffold of PP1 to its substrates. Spinophilin knockout (Spino-/-) mice have decreased fat mass, increased lean mass, and improved glucose tolerance, with no difference in feeding behaviors. Although spinophilin is enriched in neurons, its roles in nonneuronal tissues, such as β cells of the pancreatic islets, are unclear. We have corroborated and expanded upon previous studies to determine that Spino-/- mice have decreased weight gain and improved glucose tolerance in two different models of obesity. We have identified multiple putative spinophilin-interacting proteins isolated from intact pancreas and observed increased interactions of spinophilin with exocrine, ribosomal, and cytoskeletal protein classes that normally act to mediate peptide hormone production, processing, and/or release in Leprdb/db and/or high-fat diet-fed (HFF) models of obesity. In addition, we have found that spinophilin interacts with proteins from similar classes in isolated islets, suggesting a role for spinophilin in the pancreatic islet. Consistent with a pancreatic β cell type-specific role for spinophilin, using our recently described conditional spinophilin knockout mice, we found that loss of spinophilin specifically in pancreatic β cells improved glucose tolerance without impacting body weight in chow-fed mice. Our data further support the role of spinophilin in mediating pathophysiological changes in body weight and whole body metabolism associated with obesity. Our data provide the first evidence that pancreatic spinophilin protein interactions are modulated by obesity and that loss of spinophilin specifically in pancreatic β cells impacts whole body glucose tolerance.NEW & NOTEWORTHY To our knowledge, these data are the first to demonstrate that obesity impacts spinophilin protein interactions in the pancreas and identify spinophilin specifically in pancreatic β cells as a modulator of whole body glucose tolerance.

GLP-1 analogue semaglutide regulates pancreatic beta-cell proliferation via PDX-1 expression control

Semaglutide as an agonist of glucagon-like peptide-1 receptor was shown to potentiate insulin release and suppress food motivation targeting pancreatic islet beta cells and brain region including subfornical organ and hypothalamus, which effectively treats type 2 diabetes and obesity. The investigation of prolonged response with semaglutide on beta cells triggering proliferation and apoptotic resistance is yet to be confirmed. Previous research findings have shown that glucagon-like peptide-1 and liraglutide as agonists for glucagon-like peptide-1 receptors on beta cells result in proliferation through upregulation of PDX-1 transcription factor. Semaglutide is investigated to show whether long-term beta cell survival regulation is achieved through the same downstream signalling pathways. Both in vivo and in vitro methods were designed to show the proliferation effect of the semaglutide in C57BL/6 mice using tissue imaging, cell counting and immunosorbent assay for quantitative analysis of PDX-1 expression. The proliferation effect would broaden the application of semaglutide from insulin augmentation to the sustained benefit of beta cell survival.

Global research on type 1 diabetes: A bibliometric study during 2001-2022

Objective. Type 1 diabetes (T1D) publications have increased over the past three decades. However, there is no study to address and identify gaps in this area and to plan future research. This study aims to analyze the global scientific production of T1D in terms of overall structure and hotspots. Methodology. The research literature on T1D from 2001 to 2022 was obtained and examined from the Scopus database. We then performed bibliometric analysis and network visualization using MS Excel and VOSviewer software. Results and Discussion. The global T1D research comprised 20473 publications, which witnessed 6.19% and 58.91% annual average and 10-year cumulative growth during 2001-2022. These together received 596950 citations, with an average Citation Per Paper (CPP) of 29.16. Of the total global publications, 6030 (29.45%) received external funding support from international agencies and 19553 citations (with an average CPP of 32.43). The global publications were sourced from more than 150 countries and were published in 2665 journals by 63747 authors from 24899 organizations. There is an uneven distribution of countries, organizations, and authors in T1D research, wherein 88.37%, 45.15%, and 20.66% of the global literature was contributed by the top 12 countries and top 30 organizations and authors each. The most productive countries were the USA and UK, with a global share of 30% and 11.1% respectively. The most impactful countries were Finland and the UK regarding CPP & Relative Citation Index (RCI). The Barbara Davis Center for Childhood Diabetes, USA, and the University of Colorado Anschutz Medical Campus, USA, were the most productive organizations, with 735 and 679 publications. Jaeb Center for Health Research, USA (77.03 and 2.64) and Harvard Medical School, USA (67.42 and 2.31) were the most impactful organizations regarding CPP & RCI. Pediatric Diabetes (n=1447) and Diabetes Care (n=1191) were the most productive journals, with 1447 and 1191 papers. Diabetes and Diabetes Care registered the highest CPP (81.54 and 73.88 CPP). The most significant and frequently appearing keywords were “diabetes mellitus, type 1”) (92441), “insulin dependent diabetes mellitus” (95750), “metabolism” (24911), “genetics” (11229), “autoantibodies” (8942), “c peptide” (9931) and “pancreas islet beta cell” (7191). Only 5.54% (1134) of the global publications (considered highly-cited papers) received 100 to 4654 citations since their publications and registered a total of 220.28 CPP. Conclusion. This bibliometric study indicated that most of the contributions came from developed countries and only a meager contribution from developing countries, especially South Asia, despite a significant disease burden. This analysis provides a comprehensive overview of the present status of T1D research. It enables a better understanding of T1D research over the years. It should give the researchers structured information and a comprehensive analysis to help identify gaps in the research and the hot spots in this area of research.

Silencing the FABP3 gene in insulin-secreting cells reduces fatty acid uptake and protects against lipotoxicity.

Long-term exposure of pancreatic islets to fatty acids (FAs), common in obesity, metabolic syndrome, and type 2 diabetes, leads to a compensatory hyperactivity followed by inflammation, apoptosis, dysfunctional beta cells, and results in insulin dependence of the patient. Restriction of fatty uptake by islet beta cells may protect them from lipotoxicity. Pancreatic islet beta cells express the fatty acid binding protein 3 (FABP3) to bind FAs and to orchestrate lipid signals. Based on this, we investigated whether downregulation of FABP3, by Fabp3 silencing, might slow lipid metabolism and protect against lipotoxicity in insulin-secreting cells. Neither Fabp3 silencing, nor overexpression affected the glucose-stimulated insulin secretion in absence of FAs. Fabp3 silencing decreased FA-uptake, lipid droplets formation, and the expression of the lipid accumulation-regulating gene Dgat1 in Ins1E cells. It reduced FA-induced inflammation by deactivation of NF-κB, which was associated with upregulation of IκBα and deactivation of the NF-κB p65 nuclear translocation, and the downregulation of the cytokines ILl-6, IL-1β, and TNFα. Ins1E cells were protected from the FA-induced apoptosis as assessed by different parameters including DNA degradation and cleaved caspase-3 immunoblotting. Furthermore, FABP3 silencing improved the viability, Pdx1 gene expression, and the insulin-secreting function in cells long-term cultured with palmitic acid. All results were confirmed by the opposite action rendered by FABP3 overexpression. The present data reveals that pancreatic beta cells can be protected from lipotoxicity by inhibition of FA-uptake, intracellular utilization and accumulation. FABP3 inhibition, hence, may be a useful pharmaceutical approach in obesity, metabolic syndrome, and type 2 diabetes.

Pathological evaluation of the pathogenesis of diabetes mellitus and diabetic peripheral neuropathy.

Currently, there are more than 10 million patients with diabetes mellitus in Japan. Therefore, the need to explore the pathogenesis of diabetes and the complications leading to its cure is becoming increasingly urgent. Pathological examination of pancreatic tissues from patients with type 2 diabetes reveals a decrease in the volume of beta cells because of a combination of various stresses. In human type 2 diabetes, islet amyloid deposition is a unique pathological change characterized by proinflammatory macrophage (M1) infiltration into the islets. The pathological changes in the pancreas with islet amyloid were different according to clinical factors, which suggests that type 2 diabetes can be further subclassified based on islet pathology. On the other hand, diabetic peripheral neuropathy is the most frequent diabetic complication. In early diabetic peripheral neuropathy, M1 infiltration in the sciatic nerve evokes oxidative stress or attenuates retrograde axonal transport, as clearly demonstrated by in vitro live imaging. Furthermore, islet parasympathetic nerve density and beta cell volume were inversely correlated in type 2 diabetic Goto-Kakizaki rats, suggesting that diabetic peripheral neuropathy itself may contribute to the decrease in beta cell volume. These findings suggest that the pathogenesis of diabetes mellitus and diabetic peripheral neuropathy may be interrelated.

The selective serotonin reuptake inhibitors, sertraline and paroxetine, improve islet beta-cell mass and function in vitro.

To investigate the effects of the selective serotonin reuptake inhibitors (SSRIs) sertraline and paroxetine at therapeutically relevant concentrations on beta-cell mass and function. Viability was quantified in mouse insulinoma (MIN6) beta cells and mouse islets after 48-h exposure to sertraline (1-10 μM) or paroxetine (0.01-1 μM) using the Trypan blue exclusion test. The effects of therapeutic concentrations of these SSRIs on insulin secretion were determined by static incubation and perifusion experiments, while islet apoptosis was investigated by Caspase-Glo 3/7 assay, TUNEL staining and quantitative PCR analysis. Finally, proliferation of MIN6 and mouse islet beta cells was assessed by bromodeoxyuridine (BrdU) enzyme-linked immunosorbent assay and immunofluorescence. Sertraline (0.1-1 μM) and paroxetine (0.01-0.1 μM) were well tolerated by MIN6 beta cells and islets, whereas 10 μM sertraline and 1 μM paroxetine were cytotoxic. Exposure to 1 μM sertraline and 0.1 μM paroxetine significantly potentiated glucose-stimulated insulin secretion from mouse and human islets. Moreover, they showed protective effects against cytokine- and palmitate-induced apoptosis of islets, they downregulated cytokine-induced Stat1 and Traf1 mRNA expression, and they significantly increased proliferation of mouse beta cells. Our data demonstrate that sertraline and paroxetine act directly on beta cells to enhance glucose-stimulated insulin secretion and stimulate beta-cell mass expansion by increasing proliferation and decreasing apoptosis. These drugs are therefore likely to be appropriate for treating depression in people with type 2 diabetes.