islet isolation

The β-cell plays a crucial role in the pathogenesis of type 1 diabetes, in part through the posttranslational modification of self-proteins by biochemical processes such as deamidation. These neoantigens are potential triggers for breaking immune tolerance. We report the detection by LC-MS/MS of 16 novel Gln and 27 novel Asn deamidations in 14 disease-related proteins within inflammatory cytokine-stressed human islets of Langerhans. T-cell clones responsive against one Gln and three Asn deamidated peptides could be isolated from peripheral blood of individuals with type 1 diabetes...

Islets experience enormous stress during the isolation process, leading to suboptimal endocrine function after total pancreatectomy with islet autotransplantation (TPIAT). Our investigation focused on inducing isolation stress in islets ex vivo, where proinflammatory cytokines and hypoxia prompted the release of stress exosomes (exoS ) sized between 50 and 200 nm. Mass spectrometry analysis revealed 3 distinct subgroups of immunogenic proteins within these exoS : damage-associated molecular patterns (DAMPs), chaperones, and autoantigens...

Autoimmune responses are the most important pathogenic mechanisms underlying type 1 diabetes (T1D). Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have immunomodulatory effects. In this study, we investigated whether EVs derived from human umbilical cord MSCs (HucMSC-EVs) have treatment effects on nonobese diabetic (NOD) mice as model of T1D. HucMSC-EVs were isolated from human umbilical cord MSCs and characterized. NOD mice (aged 4 weeks) were administered with HucMSC-EVs or the same volume of phosphate-buffered saline (PBS) via caudal vein injection twice per week...

Target identification is a crucial step in elucidating the mechanisms by which functional food components exert their functions. Here, we identified the G-protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5) as a target of the triterpenoid mogrol, a class of aglycone mogroside derivative from Siraitia grosvenorii. Mogrol, but not mogrosides, activated cAMP-response element-mediated transcription in a TGR5-dependent manner. Additionally, mogrol selectively activated TGR5 but not the other bile acid-responsive receptors (i...

Impeded autophagy can impair pancreatic β cell function by causing apoptosis, of which DAP-related apoptosis-inducing kinase-2 (DRAK2) is a critical regulator. Here, we identified a marked up-regulation of DRAK2 in pancreatic tissue across humans, macaques, and mice with type 2 diabetes (T2D). Further studies in mice showed that conditional knockout (cKO) of DRAK2 in pancreatic β cells protected β cell function against high-fat diet feeding along with sustained autophagy and mitochondrial function...

Mammalian cells have three types of endoplasmic reticulum (ER) stress-sensing molecules: ATF6, IRE1, and PERK. Among these, ATF6 is unique in that it is processed in an ER-stress-specific manner and functions as a transcription factor for the activation of anti-ER stress genes (such as BiP). ATF6 is known to have two homologues, ATF6α and ATF6β, and a greater understanding of their functions has been achieved through analyses using cultured cells. Physiological functions are also gradually being investigated in mice lacking ATF6α or ATF6β...

PURPOSE OF REVIEW: This review discusses evidence regarding progenitor populations of the biliary tree in the tissue regeneration and homeostasis, and the pathobiology of cholangiopathies and malignancies. RECENT FINDINGS: In embryogenesis biliary multipotent progenitor subpopulation contributes cells not only to the pancreas and gall bladder but also to the liver. Cells equipped with a constellation of markers suggestive of the primitive endodermal phenotype exist in the peribiliary glands, the bile duct glands, of the intra- and extrahepatic bile ducts...

There is growing evidence that neonatal porcine islet-like cell clusters (NPCCs) isolated from piglets can be used to treat type 1 diabetes in humans. However, graft rejection is a common complication in humans owing to the prevalence of xenoantigens in porcine. Therefore, researchers have investigated various islet encapsulation techniques that could protect against these antigens. To this end, this study presents a robust nano-encapsulation method based on bifunctional polymersomes (PSomes), in which N-hydroxysuccinimide (NHS) and maleimide (Mal) groups conjugated to the PSomes terminal interact with the amine and thiol groups on the surface of NPCCs to induce dual targeting via two covalent bonds...

OBJECTIVE: Notch signaling, re-activated in β cells from obese mice and causal to β cell dysfunction, is determined in part by transmembrane ligand availability in a neighboring cell. We hypothesized that β cell expression of Jagged1 determines the maladaptive Notch response and resultant insulin secretory defects in obese mice. METHODS: We assessed expression of Notch pathway components in high-fat diet-fed (HFD) or leptin receptor-deficient (db/db) mice, and performed single-cell RNA sequencing (scRNA-Seq) in islets from patients with and without type 2 diabetes (T2D)...

CCR5-tropic simian/human immunodeficiency viruses (SHIV) with clade C transmitted/founder envelopes represent a critical tool for the investigation of HIV experimental vaccines and microbicides in nonhuman primates, although many such isolates lead to spontaneous viral control post infection. Here, we generated a high-titer stock of pathogenic SHIV-C109p5 by serial passage in two rhesus macaques (RM) and tested its virulence in aged monkeys. The co-receptor usage was confirmed before infecting five geriatric rhesus macaques (four female and one male)...

Dipeptidyl peptidase-4 (DPP-4), a ubiquitous proteolytic enzyme, inhibits insulin secretion from pancreatic beta cells by inactivating circulating incretin hormones GLP-1 and GIP. High circulating levels of DPP-4 is presumed to compromise insulin secretion in people with type 2 diabetes (T2D). Our group recently reported lipid induced DPP-4 expression in pancreatic beta cells, mediated by the TLR4-NF-kB pathway. In the present study, we looked at the role of Vildagliptin on pancreatic DPP-4 inhibition, preservation of islet mass and restoration of insulin secretion...

Hybrid insulin peptides (HIPs) formed through covalent cross-linking of proinsulin fragments to secretory granule peptides are detectable within murine and human islets. The 2.5HIP (C-peptide-Chromogranin A (CgA) HIP), recognized by the diabetogenic BDC-2.5 clone, is a major autoantigen in the NOD mouse. However, the relevance of this epitope in human disease is currently unclear. A recent study probed T-cell reactivity toward HIPs in patients with type 1 diabetes, documenting responses in one third of the subjects and isolating several HIP-reactive T-cell clones...

AIMS: Extracellular vesicles (EVs) are involved in intercellular communication and are a topic of increasing interest due to their therapeutic potential. The aim of this study was to determine whether human islet-derived EVs contain insulin, and if so, what role do they play in glucose stimulated insulin secretion. MAIN METHODS: We isolated EVs from human islets culture and plasma to probe for insulin. Plasma from hyperglycemic glucose clamp experiments were also used to isolate and measure EV insulin content in response to a secretory stimulus...

Skeletal muscle atrophy is a disorder characterized by reductions in muscle size and strength. Cumin extract (CE) possesses anti-inflammatory, antioxidant, and hypoglycemic properties. Its pharmaceutical applications are hindered by its low water solubility and by its cytotoxicity when administered at high doses. In this study, we have developed a simplified water distillation method using a rotary evaporator to isolate the active components in cumin seeds. The anti-inflammatory effects of CE and its potential to ameliorate skeletal muscle atrophy in rats with streptozotocin (STZ)-induced diabetes were evaluated...

Pancreatic islet transplantation is a promising treatment for type 1 diabetes, but the survival and function of transplanted islets are hindered by the loss of extracellular matrix (ECM) during islet isolation and by low oxygenation upon implantation. This study aimed to evaluate the impact of hypoxia on ECM using a cutting-edge imaging approach based on tissue clearing and 3D microscopy. Human and rat islets were cultured under normoxic (O2 21%) or hypoxic (O2 1%) conditions. Immunofluorescence staining targeting insulin, glucagon, CA9 (a hypoxia marker), ECM proteins (collagen 4, fibronectin, laminin), and E-cadherin (intercellular adhesion protein) was performed on fixed whole islets...

Auckland Island pigs represent an inbred population of feral pigs isolated on the sub-Antarctic island for over 100 years. The animals have been maintained under pathogen-free conditions in New Zealand; they are well characterized virologically and have been used as donor sources in first clinical trials of porcine neonatal islet cell transplantation for the treatment of human diabetes patients. The animals do not carry any of the xenotransplantation-relevant viruses, and in the first clinical trials, no porcine viruses, including porcine endogenous retroviruses (PERVs) were transmitted to the human recipients...

BACKGROUND AND AIMS: The incidence of statin-induced new-onset diabetes (NOD) is increasing but its underlying mechanisms remain unclear. We aimed to investigate the effects of various doses of atorvastatin (ATO)-induced autophagy on the development of NOD. METHODS AND RESULTS: The isolated rat islets and MIN6 cells-treated with ATO, exhibited impaired glucose-stimulated insulin secretion, reduced insulin content, and induced apoptosis. Additionally, autophagy was induced at all doses (in vitro: 5, 10, 20 μM; in vivo: 10, 15, 20 mg/kg) in ATO-treated MIN6 cells or western diet (WD)-fed mice...

Interesterified fats have been used to replace trans-fat in ultra-processed foods. However, their metabolic effects are not completely understood. Hence, this study aimed to investigate the effects related to glucose homeostasis in response to interesterified palm oil or refined palm oil intake. Four-week-old male Swiss mice were randomly divided into four experimental groups and fed the following diets for 8 weeks: a normocaloric and normolipidic diet containing refined palm oil (PO group) or interesterified palm oil (IPO group); a hypercaloric and high-fat diet containing refined PO (POHF group) or interesterified PO (IPOHF group)...

OBJECTIVE: Aggregation of human islet amyloid polypeptide (hIAPP), a β-cell secretory product, leads to islet amyloid deposition, islet inflammation and β-cell loss in type 2 diabetes (T2D), but the mechanisms that underlie this process are incompletely understood. Receptor interacting protein kinase 3 (RIPK3) is a pro-death signaling molecule that has recently been implicated in amyloid-associated brain pathology and β-cell cytotoxicity. Here, we evaluated the role of RIPK3 in amyloid-induced β-cell loss using a humanized mouse model of T2D that expresses hIAPP and is prone to islet amyloid formation...

Cell delivery and encapsulation platforms are under development for the treatment of Type 1 Diabetes among other diseases. For effective cell engraftment, these platforms require establishing an immune-protected microenvironment as well as adequate vascularization and oxygen supply to meet the metabolic demands of the therapeutic cells. Current platforms rely on 1) immune isolating barriers and indirect vascularization or 2) direct vascularization with local or systemic delivery of immune modulatory molecules...