Search Results (1,173)

Apolipoprotein A-IV (ApoA-IV) is a glycoprotein secreted by the small intestine to regulate lipid metabolism and satiety. Its role in insulin-independent glucose homeostasis remains largely unknown. In this study, we demonstrate that intestinal ApoA-IV overexpression significantly attenuates diet-induced obesity and hyperglycemia following severe β-cell loss. Over a 20-week high-fat diet challenge, ApoA-IV transgenic (ApoA-IV-Tg) mice maintained significantly lower adiposity than wild-type controls, driven by elevated energy expenditure and fatty acid oxidation rather than reduced caloric intake. Beyond weight maintenance, ApoA-IV maintained excellent systemic glycemic control and enhanced peripheral insulin sensitivity. Most notably, ApoA-IV significantly attenuated hyperglycemia following streptozotocin (STZ)-induced β-cell ablation, maintaining glucose stability despite severe insulin deficiency. Mechanistically, this protection results from a blunted glucagon response and the subsequent suppression of the hepatic pCREB-G6Pase gluconeogenic signaling pathway. In vitro evidence confirms that ApoA-IV directly inhibits pancreatic α-cell glucagon secretion through an LDL receptor-related protein 1 (LRP1)-dependent pathway, reinforced by the precise co-localization of LRP1 and glucagon in pancreatic islets. Furthermore, ApoA-IV-Tg mice were protected from the STZ-induced corticosterone surge and systemic lipolysis. Collectively, these findings establish the ApoA-IV–LRP1 signaling axis as a potent metabolic switch, providing a promising insulin-independent strategy for managing obesity and diabetes. Full article

The protective effect of Compound terminalia chebula extract (HL) against colonic injury induced by Porcine epidemic diarrhea virus (PEDV) infection in neonatal piglets remains unclear. This study aimed to evaluate the mitigating effects of HL on PEDV-induced colonic injury and elucidate the underlying mechanisms. Eighteen 7-day-old Duroc × Landrace × Large White piglets (2.58 ± 0.05 kg) were randomly assigned to three groups (n = 6/group): CON (blank control), PEDV (infected), and HL + PEDV (HL-supplemented + infected). The 11-day trial included 3 days of acclimatization (days 0–3) and an 8-day experimental period (days 4–11). HL (10 mg/kg BW) was orally administered daily to the HL + PEDV group. On day 8, PEDV and HL + PEDV groups were challenged with 3 mL PEDV (3 × 10⁶ TCID₅₀/mL), while CON received Dulbecco’s Modified Eagle Medium (DMEM). All piglets were euthanized on day 11 for colonic tissue collection. Results indicated that PEDV infection induced colonic injury, manifested by a significant increase in crypt depth and disruption of intestinal homeostasis. This was evidenced by impaired barrier integrity (upregulation of matrix metalloproteinase-7 gene [MMP7] and matrix metalloproteinase 13 gene [MMP13], mucus disorganization (elevation of mucin 5AC gene [MUC5AC]), oxidative stress (reduced catalase [CAT] activity and increased malondialdehyde [MDA] levels in serum and colon), and inflammation (upregulation of regenerative islet-derived protein 3γ gene [REG3G], S100 calcium-binding protein A8/A9 gene [S100A8/A9], and interleukin-1β gene [IL-1β]). Additionally, PEDV impaired colonic ion transport by downregulating calcium channel genes (Transient Receptor Potential Cation Channel Subfamily V Member 6 gene [TRPV6], Transient Receptor Potential Cation Channel Subfamily M Member 6 gene [TRPM6]). Notably, HL supplementation effectively reversed these adverse effects. HL restored colonic morphology, increased CAT activity, reduced MDA accumulation, and suppressed inflammatory gene expression. Furthermore, HL modulated the expression of genes involved in water and ion transport upregulating Aquaporin 7 gene (AQP7), Chloride Channel Accessory 4 gene (CLCA4), Sodium-Hydrogen Exchanger 3 gene (NHE3), Transient Receptor Potential Vanilloid 6 (TRPV6), and Transient Receptor Potential Melastatin 6 gene (TRPM6) and significantly inhibited PEDV replication, as indicated by the downregulation of the transcription levels of PEDV membranegene (M), nucleocapsid gene (N), and spike gene (S). Taken together, HL alleviates PEDV-triggered colonic tissue damage in suckling piglets via improving colonic antioxidant capacity, mitigating inflammatory response, partially regulating intestinal barrier and ion/water transport-related genes, and downregulating the transcription of PEDV structural genes at molecular and histological levels. Full article

Background: Impaired insulin secretion by pancreatic beta cells drives chronic hyperglycemia, which characterizes type 2 diabetes mellitus. The mechanosensitive ion channel Piezo2 has been implicated in various physiological processes. However, its expression and functional role in pancreatic endocrine cells remain poorly understood. Methods: We investigated the expression, cellular localization, and potential functional significance of Piezo2 in the pancreatic islets of mice fed normal- and high-fat diets (HFD) using molecular, immunohistochemical, and immunofluorescence approaches. Results: Piezo2 mRNA and protein expression were detected in rat pancreatic tissue and the pancreatic beta cell line INS-1 via polymerase chain reaction and Western blotting analyses. Hematoxylin and eosin staining and histopathological analysis were performed to determine the localization of Piezo2, insulin, and glucagon in the islets of Langerhans from mouse pancreas. Immunofluorescence revealed that Piezo2 colocalized with insulin, glucagon, pancreatic polypeptide (PP, a pancreatic cell marker), and insulin/PP (suggesting Ppy-lineage beta cells). Piezo2 expression is significantly reduced in islets from HFD-fed mice and downregulated under high glucose conditions in INS-1 cells. Stretch stimulation, with or without D-GsMTx4 (a Piezo2-specific inhibitor), enhanced glucose-stimulated insulin secretion, whereas ruthenium red (a non-specific Piezo channel inhibitor) did not alter the response to high glucose. Conclusions: These findings demonstrate Piezo2 expression in pancreatic islets and suggest that it is enriched in beta cells and Ppy-lineage beta cells, minority in alpha cells and is responsive to metabolic stress. Although Piezo2 may contribute to beta-cell adaptation, its role in insulin secretion remains unclear. Full article

It is unknown whether the glucagon-like peptide-1 (GLP-1) receptor agonists have a significant protective effect against acute islet injury. High mobility group box 1 (HMGB1) is a damage-associated molecular pattern (DAMP) molecule released from stressed or injured pancreatic β-cells, which triggers inflammatory responses through toll-like receptor 4 (TLR4) signaling. This study investigated the protective effect and mechanism of liraglutide on acute islet injury induced by low doses of streptozotocin (STZ). The results showed that liraglutide pretreatment preserved the structural integrity of pancreatic islets, improved insulin levels and glucose tolerance, and significantly reduced the incidence of diabetes in STZ-treated mice. Liraglutide was also found to inhibit STZ-induced release of HMGB1 and reduce the expression of TLR4 and inflammatory factors IFN-γ, IL-1β, and CXCL10. Moreover, administration of exogenous HMGB1 or antagonism of the GLP-1 receptor diminished liraglutide’s protective effects. These findings suggest that liraglutide has a strong protective effect on STZ-induced acute islet injury, most likely through the inhibition of HMGB1 release, which provides an experimental basis for the application of liraglutide as a protective agent for acute islet injury. Full article

Background/Objectives: Gamma-aminobutyric acid (GABA) is increasingly recognized as an important modulator of pancreatic beta-cell function, but the mechanisms by which it regulates intracellular Ca²⁺ oscillations and coordinated beta-cell activity remain insufficiently understood. The aim of this study was to investigate how GABA influences the amplitude, frequency, phase adjustment, entrainment, and synchronization of beta-cell Ca²⁺ oscillations. Methods: We developed a reduced ATP–Ca²⁺ oscillation model, based on established beta-cell oscillatory frameworks, and coupled it to the GABA-shunt subsystem derived from our previously established Dual Anaplerotic Model. The model incorporates explicit dynamics of cytosolic Ca²⁺, endoplasmic reticulum Ca²⁺, ATP, and a regulatory variable controlling Ca²⁺ influx, while the interstitial GABA signal is represented as a delayed feedback signal acting on cellular excitability. Single-cell and two-cell simulations were performed to analyze GABA-dependent oscillatory regulation and intercellular coupling. Results: The model reproduced key experimental observations under both control and GABA-deficient conditions, including reduced Ca²⁺-oscillation amplitude and a prolonged oscillation period when GABA production was suppressed. Mechanistically, GABA affected single-cell oscillations through two complementary pathways: metabolically, by modulating ATP production through PEP-related and TCA-related contributions linked to the GABA shunt, and as an interstitial/paracrine signal, by adjusting the phase of Ca²⁺ influx through fast and delayed inhibitory feedback. In the reduced two-cell model, delayed interstitial GABA signaling could phase-lock non-identical oscillators over finite ranges of parameter mismatch. When included as an additional weak effective term, electrical coupling broadened these ranges, consistent with a complementary interaction between GABA-mediated phase adjustment and established electrical coupling. Conclusions: GABA acts as a dual regulator of beta-cell dynamics, linking intracellular metabolism to Ca²⁺-oscillation patterning and promoting coordinated activity through intercellular phase adjustment. The model provides a mechanistic framework connecting GABA metabolism, ATP dynamics, Ca²⁺ signaling, and beta-cell synchronization in pancreatic islets. Full article

Dynamic insulin secretion and glucose homeostasis are dependent on the appropriate maturation and function of pancreatic β-cells. The islet-enriched musculoaponeurotic fibrosarcoma oncogene family A (MAFA) transcription factor acts as a master regulator of β-cell identity and function, coordinating gene expression networks required for glucose-stimulated insulin secretion. Dysregulation of MAFA contributes to β-cell dysfunction, as reduced expression is detected early in the pathogenesis of Type 1 Diabetes and Type 2 Diabetes, while long-lived variants can drive monogenic forms of diabetes. In this review, we summarize the current understanding of MAFA on β-cell maturation and function in both the mouse and human. This includes structural features of the MAFA protein, regulation of MAFA transcription, post-translational modifications, and emerging areas of research for therapeutic potential. Full article

Rotavirus infection is a major cause of acute gastroenteritis in children, which is characterized by fever, emesis, and diarrhea. In some children, rotaviral infection can spread beyond the gastrointestinal tract and affect the nervous system, kidneys, liver, or pancreas. There are relatively few longitudinal studies of such long-term sequalae. One area of interest has been damage to pancreatic beta islet cells, the lack of which causes type 1 diabetes mellitus. This chronic disease can be life threatening, especially in young children, and is associated with lifelong elevated risks of cardiovascular disease, neuropathy, nephropathy, and retinopathy. This narrative review summarizes the scientific evidence relevant to rotavirus infection and early-onset type 1 diabetes. The results of epidemiologic, animal, and laboratory research indicate that rotavirus infection increases the risk of type 1 diabetes in young children (<5 years of age). Rotavirus vaccination is associated with lower incidence rates; the data suggest a somewhat stronger effect with the pentavalent vaccine than the monovalent vaccine. Continued surveillance of both rotavirus infection and type 1 diabetes are necessary, considering the increases in vaccine hesitancy. The benefits of rotavirus vaccination should be discussed with parents and individuals planning to have children. Full article

Type 1 diabetes (T1D) is an autoimmune disease characterized by β-cell destruction as a common trait, in which variability in age at onset, progression rate, and clinical presentation shape heterogeneous phenotypes. Disentangling this heterogeneity is pivotal for a better understanding of clinical risk, evolution and a precision medicine approach to the disease. In this context, circulating islet autoantibodies, including the last discovered Zinc Transporter 8 autoantibodies (ZnT8A), represent crucial tools. This narrative review provides an overview of the current knowledge on ZnT8A in autoimmune diabetes from its structural and pathogenetic basis to its clinical relevance and therapeutic perspectives. A literature search was conducted in PubMed, Scopus, Google Scholar, and ResearchGate up to March 2026, that included preclinical, pediatric, adult, and assay-comparison studies. While the identification of ZnT8-targeted antigenic determinants is still ongoing, we discuss the pathogenic role of a newly identified specific class of antibodies directed against extracellular ZnT8 epitopes (ZnT8ecA). According to this finding, ZnT8ecA could facilitate the identification of an early phase of islet injury process, holding promise to provide a framework for new therapeutic strategies based on masking or modulating surface-exposed ZnT8 epitopes and interfering with the early stages of the disease. Moving from the role of ZnT8A in various clinical settings, we also focus on recent advancements in detection technologies, whose implementation accounts for invaluable contributions to diagnosis, disease risk, and, contextually, to a better understanding of autoimmune diabetes. Finally, we provide future perspectives, in T1D and T1-related diseases, for the potential clinical application of ZnT8A in early diagnosis, risk stratification and profiling, as well as in the development of targeted therapies as part of precision medicine. Full article

Background/Objectives: Type 1 diabetes (T1D) is an autoimmune disease characterized by progressive β-cell loss. Apolipoprotein CIII (apoCIII), a lipid metabolism regulator, is elevated in T1D and implicated in β-cell apoptosis. Antisense oligonucleotide–mediated apoCIII reduction delays diabetes onset in diabetes-prone BioBreeding (DPBB) rats. This study examined whether small-interfering RNA (siRNA) targeting apoCIII during the final prediabetic month preserves islet integrity and delays T1D onset. Methods: Two siRNAs targeting rat apoCIII were evaluated in 30-day-old DPBB rats for efficacy and off-target effects. Hepatic and plasma apoCIII levels were measured, and neighboring apolipoprotein gene expression was assessed. The most specific candidate (apoCIII-siRNA2) was selected. Duration of action was determined after a single injection. To study the effects of apoCIII-lowering treatment in vivo, islets from 25-day-old DPBB rats were transplanted into the anterior chamber of the eye of age-matched DPBB recipients. Rats received weekly intravenous injections of apoCIII-siRNA2 from day 30 until diabetes onset. Islet morphology, vascularization, and phagocyte infiltration were assessed by confocal imaging three and five weeks post-transplantation. Results: Both siRNAs reduced apoCIII, but one showed off-target effects and was excluded. A single injection of apoCIII-siRNA2 suppressed plasma apoCIII for approximately one week and weekly treatment maintained low circulating apoCIII levels. Five weeks after transplantation islet morphology and vascularization were preserved, and there was no increase in phagocyte infiltration. This resulted in a delayed onset of diabetes. Conclusions: siRNA-mediated apoCIII reduction delays pancreatic islet deterioration and T1D onset in DPBB rats, supporting apoCIII as a contributing factor to β-cell vulnerability and thereby a potential therapeutic target. Full article

Variants in the human PAX4 gene are associated with both monogenic and complex forms of diabetes, yet their pathogenic effects remain difficult to define in models that accurately mimic human islet architecture and neonatal metabolic transitions. Here, we created a porcine PAX4 loss-of-function model using CRISPR/Cas9 cytidine deaminase base editing to introduce a premature stop codon in the PAX4 coding sequence. PAX4 knockout piglets developed severe hyperglycemia within 24 h of birth, followed by rapid postnatal clinical deterioration and uniform death by day 3. Biochemical analysis showed significant diabetic decompensation, including electrolyte imbalances, hyperosmolality, azotemia, dyslipidemia, and metabolic acidosis. Gross and histological examinations revealed notable pancreatic hypoplasia with preservation of exocrine tissue. Single-nucleus RNA sequencing and immunohistochemistry demonstrated an almost complete loss of insulin- and somatostatin-producing β- and δ-cells, respectively, with relative preservation of glucagon-expressing α-cells. Overall, these results establish PAX4 as a crucial factor in pancreatic endocrine development and postnatal glucose regulation in a large-animal model. This platform offers a human-relevant system for studying diabetes-associated PAX4 variants and for testing regenerative and gene-based therapies for insulin-deficient diabetes. Full article

Diabetes mellitus represents a major global health challenge with rapidly increasing prevalence and substantial morbidity driven by metabolic and vascular complications. Extracellular vesicles (EVs) have emerged as critical mediators of intercellular communication and are increasingly implicated in the pathogenesis and progression of diabetes. This review summarizes current knowledge on EV biology, including their classification, cellular sources, biogenesis, uptake mechanisms, and molecular cargo. We discuss the contribution of EV-associated microRNAs to immune dysregulation and β-cell damage in type 1 diabetes mellitus (T1DM), as well as the role of EVs in insulin resistance, metabolic signaling, and vascular dysfunction in type 2 diabetes mellitus (T2DM). Particular emphasis is placed on EV-mediated modulation of endothelial function, angiogenesis, and tissue repair, alongside their involvement in the impairment of insulin receptor integrity. We further explore how lifestyle factors may influence EV composition and function, highlighting their potential integration into preventive strategies. Finally, we evaluate the emerging therapeutic potential of EVs as biomarkers and delivery systems, while addressing current limitations and future directions. Collectively, EVs represent a promising frontier in understanding diabetes pathophysiology and developing innovative diagnostic and therapeutic approaches. Unlike previous reviews that examine EVs separately as biomarkers or therapeutic vehicles, this review integrates emerging evidence supporting EVs as mediators of systemic communication linking pancreatic islets, adipose tissue, immune cells, vascular endothelium, kidney, heart, and retina throughout diabetes progression. We further critically evaluate translational barriers that currently limit clinical implementation of EV-based diagnostics and therapeutics. Full article

Gallotia simonyi and G. bravoana are large lacertids inhabiting the islands of El Hierro and La Gomera, respectively, in the Canary Archipelago. Both species are critically endangered, but over the last several decades, they have been bred in outdoor terraria (G. simonyi since the 1990s and G. bravoana since 2000). In this study: (1) we describe all procedures carried out in the breeding centres and quantitatively analyse the long-term trajectory of breeding success throughout the study period; (2) we examine whether any parental individuals or specific pairs had a stronger influence on the number of successfully hatched offspring; (3) we report the trials of reintroducing individuals into the wild on each island in different years; (4) we provide information on several predator (cat-control) campaigns conducted on each island; (5) we detail the veterinary protocols and the results obtained when assessing the health status of breeding lizards; and (6) we report several educational activities carried out on each island. Gravid females laid eggs in suitable laying boxes; the eggs were then kept inside incubators with controlled temperature and humidity until hatching. Breeding produced 1267 offspring during the years considered for G. simonyi and 499 for G. bravoana. The mean NEL was 8.8 for G. simonyi and 5.2 for G. bravoana, and the mean HO was 6.4 and 3.54, respectively. Both NEL and HO were significantly higher in G. simonyi than in G. bravoana. NEL was significantly influenced by species and year, and by female snout–vent length (SVL) as a covariate, but not by male SVL. HO was significantly affected by year and by both male and female SVL, but not by species. There were significantly higher or lower values of both variables in specific years, but no clear long-term trend. Some breeding pairs had a greater influence on the dependent variables. Reintroduction into the wild has resulted in a currently stable population of G. simonyi on a small islet off the north-western coast of El Hierro, and some individuals are still present at an inland reintroduction site. For G. bravoana, some live specimens have recently been detected at a new reintroduction site. We conclude that: (1) captive breeding has been successfully carried out over the years in both centres; (2) there have been significant differences between the two species in NEL and HO; (3) female SVL was significantly related to both NEL and HO; and (4) reintroduction attempts have been only partially successful in each species. Veterinary monitoring revealed high dehydration tolerance, seasonal fluctuations in microbial flora, previous mineral imbalances that were corrected by improved nutrition, and effective parasite control that maintained overall lizard health. Except for a few individuals, most lizards were in good health. Full article

Background: Pathological aggregation of islet amyloid polypeptide (IAPP) contributes to β-cell dysfunction in type 2 diabetes. Our previous studies demonstrated that caveolin-1 (Cav-1) deficiency protects β-cells from palmitate-induced apoptosis. Microarray profiling further indicated that Cav-1 silencing alters IAPP expression. This study aimed to investigate the effects of Cav-1 depletion on IAPP secretion and expression and to explore the potential involvement of thioredoxin-interacting protein (TXNIP). Methods: We performed lentiviral-mediated Cav-1 knockdown in NIT-1 cells and isolated murine islets, and simultaneously generated an inducible β-cell-specific Cav-1 knockout (iβ-Cav1 KO) mouse model. IAPP secretion and expression were assessed by ELISA, Western blot, qPCR and immunofluorescence. The expression of IAPP-processing enzymes (PAM, PC1, and PC2) and degradation factors (IDE and BACE2) was examined. Co-immunoprecipitation (Co-IP) and immunofluorescence were performed to investigate the interaction between Cav-1 and TXNIP. Results: Cav-1 depletion significantly reduced both IAPP secretion and expression in vitro and in vivo. High-fat-diet-fed iβ-Cav1 KO mice exhibited the lowest serum IAPP levels. Mechanistically, Cav-1 depletion was associated with downregulation of PAM, PC1, and PC2 and upregulation of IDE and BACE2. Additionally, Cav-1 depletion decreased TXNIP expression. Immunofluorescence revealed co-localization of Cav-1 and TXNIP, and co-immunoprecipitation further demonstrated their direct physical interaction. Conclusions: Cav-1 is essential for IAPP secretion and expression in β-cells. The direct physical interaction between Cav-1 and TXNIP suggests that TXNIP may mediate the regulatory effects of Cav-1 on IAPP processing or secretion. These findings identify the Cav-1–TXNIP axis as a potential target for mitigating IAPP-related β-cell dysfunction. Full article

Background: Type 2 diabetes is projected to affect millions of people annually as the number of cases rises year on year. This includes children. Treating diabetes and its related comorbidities has a huge economic impact and puts pressure on healthcare providers. Understanding the disease at a molecular level is key for developing better therapeutics. The protein Islet Amyloid Polypeptide (IAPP) or amylin is important for glucose regulation; however, it is also instrumental in type 2 diabetes pathology. Human IAPP can misfold into oligomers and amyloid fibrillar aggregates within pancreatic islets, promoting β-cell dysfunction and death, contributing to progressive insulin deficiency and worsening hyperglycaemia. Methods: Based on previous studies on mutations at residues 18, 28 and 31,we have designed three novel IAPP analogues (two double and one triple mutant) to assess whether the combined amino acid substitutions impact fibril formation, solubility and toxicity. Results: All three of our analogues show a reduced propensity to aggregate and are more soluble than wild type IAPP. Compared with pramlintide, a clinically prescribed synthetic analogue of human amylin, all of our analogues appeared to have similarly reduced toxicity and improved solubility relative to human IAPP. Additionally, two of our analogues exhibited a markedly slower rate of fibril formation. Conclusions: Our results highlight the importance of targeting multiple residues as a promising strategy for developing improved diabetes therapeutics in the future. Full article

Type 1 diabetes is caused by autoimmune destruction of insulin-secreting β-cells within islets of Langerhans. Transplantation of donor islets can improve glycaemic control, but current clinical islet transplantation protocols are compromised by extensive loss of β-cell functional mass soon after implantation. Co-incubation in vitro or co-transplantation in vivo of mesenchymal stromal cells (MSCs) with isolated islets improves their functional survival, although the underlying mechanisms remain obscure. Here, we show that MSC-derived extracellular vesicles (MSC-EVs) are alone sufficient to recapitulate many of the beneficial effects of MSCs on islet functional survival, offering the possibility of simple cell-free treatments to improve the outcomes of islet transplantation. We used LC- analysis and small RNA sequencing to analyse the protein and microRNA (miRNA) molecular cargos of MSC-EVs. Proteomic analysis identified >100 proteins from the Uniprot Mouse Database, including β-cell G protein-coupled receptor (GPCR) agonists which we have previously shown to enhance β-cell functional survival. MSC-EVs contained ~300 distinct miRNAs and we identified five highly enriched miRNAs that were significantly upregulated in MSC-EV-treated islets, notably miR-21a-5p. MSC-EV treatment also altered the expression of a distinct set of islet mRNAs known to be involved in islet metabolism and function. These observations may enable the further simplification of the islet pretreatment strategy by focusing on defined GMP-grade biologically active molecules rather than whole heterogeneous EV populations. Full article