RESUMEN

Sodium butyrate (NaB) improves ß-cell function in preclinical models of diabetes; however, the mechanisms underlying these beneficial effects have not been fully elucidated. In this study, we investigated the impact of NaB on ß-cell function and calcium (Ca2+) signaling using ex vivo and in vitro models of diabetes. Our results show that NaB significantly improved glucose-stimulated insulin secretion in islets from human organ donors with type 2 diabetes and in cytokine-treated INS-1 ß cells. Consistently, NaB improved glucose-stimulated Ca2+ oscillations in mouse islets treated with proinflammatory cytokines. Because the oscillatory phenotype of Ca2+ in the ß cell is governed by changes in endoplasmic reticulum (ER) Ca2+ levels, we explored the relationship between NaB and store-operated calcium entry (SOCE), a rescue mechanism that acts to refill ER Ca2+ levels through STIM1-mediated gating of plasmalemmal Orai channels. We found that NaB treatment preserved basal ER Ca2+ levels and restored SOCE in IL-1ß-treated INS-1 cells. Furthermore, we linked these changes with the restoration of STIM1 levels in cytokine-treated INS-1 cells and mouse islets, and we found that NaB treatment was sufficient to prevent ß-cell death in response to IL-1ß treatment. Mechanistic experiments revealed that NaB mediated these beneficial effects in the ß-cell through histone deacetylase (HDAC) inhibition, iNOS suppression, and modulation of AKT-GSK-3 signaling. Taken together, these data support a model whereby NaB treatment promotes ß-cell function and Ca2+ homeostasis under proinflammatory conditions through pleiotropic effects that are linked with maintenance of SOCE. These results also suggest a relationship between ß-cell SOCE and gut microbiome-derived butyrate that may be relevant in the treatment and prevention of diabetes.

Asunto(s)

Ácido Butírico , Calcio , Células Secretoras de Insulina , Molécula de Interacción Estromal 1 , Animales , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Molécula de Interacción Estromal 1/metabolismo , Ratones , Humanos , Ácido Butírico/farmacología , Calcio/metabolismo , Citocinas/metabolismo , Señalización del Calcio/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Retículo Endoplásmico/metabolismo , Diabetes Mellitus Tipo 2/metabolismo

RESUMEN

Dual-specificity tyrosine phosphorylation-regulated kinase A (DYRK1A) is a potential drug target for diabetes. The DYRK1A inhibitor can promote ß cells proliferation, increase insulin secretion and reduce blood sugar in diabetes. In this paper, a series ß-carboline-cinnamic acid skeletal derivatives were designed, synthesized and evaluated to inhibit the activity of DYRK1A and promote pancreatic islet ß cell proliferation. Pharmacological activity showed that all of the compounds could effectively promote pancreatic islet ß cell proliferation at a concentration of 1 µM, and the cell viability of compound A1, A4 and B4 reached to 381.5 %, 380.2 % and 378.5 %, respectively. Compound A1, A4 and B4 could also inhibit the expression of DYRK1A better than positive drug harmine. Further mechanistic studies showed that compound A1, A4 and B4 could inhibit DYRK1A protein expression via promoting its degradation and thus enhancing the expression of proliferative proteins PCNA and Ki67. Molecular docking showed that ß-carboline scaffold of these three compounds was fully inserted into the ATP binding site and formed hydrophobic interactions with the active pocket. Besides, these three compounds were predicted to possess better drug-likeness properties using SwissADME. In conclusion, compounds A1, A4 and B4 were potent pancreatic ß cell proliferative agents as DYRK1A inhibitors and might serve as promising candidates for the treatment of diabetes.

Asunto(s)

Carbolinas , Proliferación Celular , Cinamatos , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Quinasas DyrK , Simulación del Acoplamiento Molecular , Inhibidores de Proteínas Quinasas , Proteínas Serina-Treonina Quinasas , Proteínas Tirosina Quinasas , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Carbolinas/farmacología , Carbolinas/química , Carbolinas/síntesis química , Proliferación Celular/efectos de los fármacos , Relación Estructura-Actividad , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Estructura Molecular , Cinamatos/farmacología , Cinamatos/química , Cinamatos/síntesis química , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Hipoglucemiantes/farmacología , Hipoglucemiantes/síntesis química , Hipoglucemiantes/química , Humanos , Animales , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/metabolismo , Supervivencia Celular/efectos de los fármacos

RESUMEN

Macroautophagy/autophagy is an essential degradation process that removes abnormal cellular components, maintains homeostasis within cells, and provides nutrition during starvation. Activated autophagy enhances cell survival during stressful conditions, although overactivation of autophagy triggers induction of autophagic cell death. Therefore, early-onset autophagy promotes cell survival whereas late-onset autophagy provokes programmed cell death, which can prevent disease progression. Moreover, autophagy regulates pancreatic ß-cell functions by different mechanisms, although the precise role of autophagy in type 2 diabetes (T2D) is not completely understood. Consequently, this mini-review discusses the protective and harmful roles of autophagy in the pancreatic ß cell and in the pathophysiology of T2D.

RESUMEN

Polypeptide N-Acetylgalactosaminyl transferase 14 (GALNT14) plays important roles in cancer progression and chemotherapy response. Here, we show that GALNT14 is highly expressed in pancreatic ß cells and regulates ß cell function and growth. We found that the expression level of Ganlt14 was significantly decreased in the primary islets from three rodent type-2 diabetic models. Single-Cell sequencing defined that Galnt14 was mainly expressed in ß cells of mouse islets. Galnt14 knockout (G14KO) INS-1 cell line, constructed by using CRISPR/Cas9 technology were growth normal, but showed blunt shape, and increased basal insulin secretion. Combined proteomics and glycoproteomics demonstrated that G14KO altered cell-to-cell junctions, communication, and adhesion. Insulin receptor (IR) and IGF1-1R were indirectly confirmed for GALNT14 substrates, contributed to diminished IGF1-induced p-AKT levels and cell growth in G14KO cells. Overall, this study uncovers that GALNT14 is a novel modulator in regulating ß cells biology, providing a missing link of ß cells O-glycosylation to diabetes development.

Asunto(s)

Proliferación Celular , Células Secretoras de Insulina , N-Acetilgalactosaminiltransferasas , Polipéptido N-Acetilgalactosaminiltransferasa , N-Acetilgalactosaminiltransferasas/metabolismo , N-Acetilgalactosaminiltransferasas/genética , Animales , Células Secretoras de Insulina/metabolismo , Ratones , Receptor IGF Tipo 1/metabolismo , Receptor IGF Tipo 1/genética , Ratones Endogámicos C57BL , Receptor de Insulina/metabolismo , Receptor de Insulina/genética , Masculino , Línea Celular , Ratones Noqueados , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patología , Transducción de Señal , Insulina/metabolismo , Secreción de Insulina/efectos de los fármacos

RESUMEN

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 ATF6ß, 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 ATF6ß. However, little is known about the effects on mouse organisms of the deletion of both the ATF6α and ATF6ß genes, since such double-knockout (DKO) mice suffer embryonic lethality at an early developmental stage. In this study, we generated and analyzed ATF6 DKO mice in which embryonic lethality was evaded by using Cre/loxP technology. Pancreatic ß cell-specific ATF6 DKO mice were born normally and lived without dysregulation of blood-glucose levels but had a reduced tolerance to glucose. Islets isolated from ATF6 DKO mice also showed low production and secretion of insulin and mild enhancement of IRE1 and PERK activity. We further examined the developmental abnormalities of systemic ATF6 DKO mice. The phenotypes of ATF6α-/-; ATF6ß-/- mice were similar to those previously reported, but ATF6α+/-; ATF6ß-/- and ATF6α-/-; ATF6ß+/- mice showed embryonic lethality at middle developmental stages, unlike those reported. Analysis of embryonic fibroblasts derived from these mice revealed that ATF6α and ATF6ß have a gene-dose-dependent functional redundancy and display distinct differences in their ability to induce BiP expression. (250 words).

Asunto(s)

Retículo Endoplásmico , Factores de Transcripción , Ratones , Animales , Retículo Endoplásmico/metabolismo , Factores de Transcripción/metabolismo , Respuesta de Proteína Desplegada , Estrés del Retículo Endoplásmico , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Glucosa/metabolismo , Factor de Transcripción Activador 6/genética , Factor de Transcripción Activador 6/metabolismo , Mamíferos

RESUMEN

OBJECTIVE: Numerous studies have highlighted the role of clock genes in diabetes disease and pancreatic ß cell functions. However, whether rhythmic long non-coding RNAs involve in this process is unknown. METHODS: RNA-seq and 3' rapid amplification of cDNA ends (RACE)-PCR were used to identify the rat LncCplx2 in pancreatic ß cells. The subcellular analysis with qRT-PCR and RNA-Scope were used to assess the localization of LncCplx2. The effects of LncCplx2 overexpression or knockout (KO) on the regulation of pancreatic ß cell functions were assessed in vitro and in vivo. RNA-seq, immunoblotting (IB), Immunoprecipitation (IP), RNA pull-down, and chromatin immunoprecipitation (ChIP)-PCR assays were employed to explore the regulatory mechanisms through LncRNA-protein interaction. Metabolism cage was used to measure the circadian behaviors. RESULTS: We first demonstrate that LncCplx2 is a conserved nuclear long non-coding RNA and enriched in pancreatic islets, which is driven by core clock transcription factor BMAL1. LncCplx2 is downregulated in the diabetic islets and repressed by high glucose, which regulates the insulin secretion in vitro and ex vivo. Furthermore, LncCplx2 KO mice exhibit diabetic phenotypes, such as high blood glucose and impaired glucose tolerance. Notably, LncCplx2 deficiency has significant effects on circadian behavior, including prolonged period duration, decreased locomotor activity, and reduced metabolic rates. Mechanistically, LncCplx2 recruits EZH2, a core subunit of polycomb repression complex 2 (PRC2), to the promoter of target genes, thereby silencing circadian gene expression, which leads to phase shifts and amplitude changes in insulin secretion and cell cycle genes. CONCLUSIONS: Our results propose LncCplx2 as an unanticipated transcriptional regulator in a circadian system and suggest a more integral mechanism for the coordination of circadian rhythms and glucose homeostasis.

Asunto(s)

Proteínas Adaptadoras del Transporte Vesicular , Diabetes Mellitus , Células Secretoras de Insulina , Proteínas del Tejido Nervioso , ARN Largo no Codificante , Animales , Ratones , Ratas , Diabetes Mellitus/metabolismo , Glucosa/metabolismo , Homeostasis/genética , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas Adaptadoras del Transporte Vesicular/genética

RESUMEN

Histone deacetylase inhibitors (HDIs) modulate ß cell function in preclinical models of diabetes; however, the mechanisms underlying these beneficial effects have not been determined. In this study, we investigated the impact of the HDI sodium butyrate (NaB) on ß cell function and calcium (Ca2+) signaling using ex vivo and in vitro models of diabetes. Our results show that NaB significantly improved glucose-stimulated insulin secretion in islets from human organ donors with type 2 diabetes and in cytokine-treated INS-1 ß cells. Consistently, NaB partially rescued glucose-stimulated Ca2+ oscillations in mouse islets treated with proinflammatory cytokines. Because the oscillatory phenotype of Ca2+ in the ß cell is governed by changes in endoplasmic reticulum (ER) Ca2+ levels, next we explored the relationship between NaB and store-operated calcium entry (SOCE), a rescue mechanism that acts to refill ER Ca2+ levels through STIM1-mediated gating of plasmalemmal Orai channels. We found that NaB treatment preserved basal ER Ca2+ levels and restored SOCE in IL-1ß-treated INS-1 cells. Furthermore, we linked these changes with the restoration of STIM1 levels in cytokine-treated INS-1 cells and mouse islets, and we found that NaB treatment was sufficient to prevent ß cell death in response to IL-1ß treatment. Mechanistically, NaB counteracted cytokine-mediated reductions in phosphorylation levels of key signaling molecules, including AKT, ERK1/2, glycogen synthase kinase-3α (GSK-3α), and GSK-3ß. Taken together, these data support a model whereby HDI treatment promotes ß cell function and Ca2+ homeostasis under proinflammatory conditions through STIM1-mediated control of SOCE and AKT-mediated inhibition of GSK-3.

RESUMEN

Pancreatic islet microencapsulation allows transplantation of insulin producing cells in absence of systemic immunosuppression, but graft survival is still limited. In vivo studies have demonstrated that many islet-cells die in the immediate period after transplantation. Here we test whether intracapsular inclusion of ECM components (collagen IV and RGD) with necrostatin-1 (Nec-1), as well as amino acids (AA) have protective effects on islet survival. Also, the inclusion of pectin was tested as it enhances the mitochondrial health of ß-cells. To enhance the longevity of encapsulated islets, we studied the impact of the incorporation of the mentioned components into the alginate-based microcapsules in vitro. The efficacy of the different composite microcapsules on MIN6 ß-cell or human islet-cell survival and function, as well as suppression of DAMP-induced immune activation, were determined. Finally, we examined the mitochondrial dynamic genes. This was done in the absence and presence of a cytokine cocktail. Here, we found that composite microcapsules of APENAA improved insulin secretion and enhanced the mitochondrial activity of ß-cells. Under cytokine exposure, they prevented the cytokine-induced decrease of mitochondrial activity as well as viability till day 5. The rescuing effects of the composite capsules were accompanied by alleviated mitochondrial dynamic gene expression. The composite capsule strategy of APENAA might support the longevity of microencapsulated ß-cells by lowering susceptibility to inflammatory stress. Our data demonstrate that combining strategies to support ß-cells by changing the intracapsular microenvironment might be an effective way to preserve islet graft longevity in the immediate period after transplantation.

Asunto(s)

Células Secretoras de Insulina , Trasplante de Islotes Pancreáticos , Humanos , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Cápsulas , Citocinas/metabolismo

RESUMEN

Ferroptosis, a new type of cell death, is associated with pancreatic ß cell damage. However, the role of glucolipotoxicity in inducing ß cell ferroptosis remains unclear. Metformin (Met), exenatide (Exe), and saxagliptin (Sax) are frequently used anti-hyperglycaemic drugs. However, their protective effects on ß cells through ferroptosis modulation are not well-established. In this study, we observed significant ferroptosis in NIT-1 cells and primary mouse islets after exposure to high glucose and palmitate (HG/PA). Compared to Exe and Sax, Met significantly alleviated glucolipotoxicity-induced pancreatic ß cell ferroptosis. Blocking the activity of glutathione peroxidase 4 (GPX4) with Ras-selective lethal 3 or inhibiting its expression by small interfering RNA transfection significantly attenuated the anti-ferroptosis effects of Met. Mechanistically, Met alleviates HG/PA-induced ß cell ferroptosis by regulating the GPX4/ACSL4 axis. Collectively, our findings highlight the significance of ferroptosis in pancreatic ß cell glucolipotoxicity-induced injury and provide novel insights into the protective effects of Met on islet ß cells.

Asunto(s)

Ferroptosis , Células Secretoras de Insulina , Islotes Pancreáticos , Metformina , Animales , Ratones , Muerte Celular , Células Secretoras de Insulina/metabolismo , Metformina/farmacología

RESUMEN

The adaptive increase in insulin secretion in early stages of obesity serves as a safeguard mechanism to maintain glucose homeostasis that cannot be sustained, and the eventual decompensation of ß cells is a key event in the pathogenesis of diabetes. Here we describe a crucial system orchestrated by a transcriptional cofactor CtBP2. In cultured ß cells, insulin gene expression is coactivated by CtBP2. Global genomic mapping of CtBP2 binding sites identifies a key interaction between CtBP2 and NEUROD1 through which CtBP2 decompacts chromatin in the insulin gene promoter. CtBP2 expression is diminished in pancreatic islets in multiple mouse models of obesity, as well as human obesity. Pancreatic ß cell-specific CtBP2-deficient mice manifest glucose intolerance with impaired insulin secretion. Our transcriptome analysis highlights an essential role of CtBP2 in the maintenance of ß cell integrity. This system provides clues to the molecular basis in obesity and may be targetable to develop therapeutic approaches.

Asunto(s)

Células Secretoras de Insulina , Islotes Pancreáticos , Obesidad , Animales , Humanos , Ratones , Glucosa/metabolismo , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Obesidad/metabolismo

RESUMEN

Pancreatic ß cell secretion of insulin is crucial to the maintenance of glucose homeostasis and prevention of diseases related to glucose regulation, including diabetes. Pancreatic ß cells accomplish efficient insulin secretion by clustering secretion events at the cell membrane facing the vasculature. Regions at the cell periphery characterized by clustered secretion are currently termed insulin secretion hot spots. Several proteins, many associated with the microtubule and actin cytoskeletons, are known to localize to and serve specific functions at hot spots. Among these proteins are the scaffolding protein ELKS, the membrane-associated proteins LL5ß and liprins, the focal adhesion-associated protein KANK1, and other factors typically associated with the presynaptic active zone in neurons. These hot spot proteins have been shown to contribute to insulin secretion, but many questions remain regarding their organization and dynamics at hot spots. Current studies suggest microtubule- and F-actin are involved in regulation of hot spot proteins and their function in secretion. The hot spot protein association with the cytoskeleton networks also suggests a potential role for mechanical regulation of these proteins and hot spots in general. This perspective summarizes the existing knowledge of known hot spot proteins, their cytoskeletal-mediated regulation, and discuss questions remaining regarding mechanical regulation of pancreatic beta cell hot spots.

RESUMEN

Maternal overnutrition is associated with increased susceptibility to type 2 diabetes in the offspring. Rodent models have shown that maternal overnutrition influences islet function in offspring. To determine whether maternal Western-style diet (WSD) alters prejuvenile islet function in a model that approximates that of human offspring, we utilized a well-characterized Japanese macaque model. We compared islet function from offspring exposed to WSD throughout pregnancy and lactation and weaned to WSD (WSD/WSD) compared with islets from offspring exposed only to postweaning WSD (CD/WSD) at 1 yr of age. WSD/WSD offspring islets showed increased basal insulin secretion and an exaggerated increase in glucose-stimulated insulin secretion, as assessed by dynamic ex vivo perifusion assays, relative to CD/WSD-exposed offspring. We probed potential mechanisms underlying insulin hypersecretion using transmission electron microscopy to evaluate ß-cell ultrastructure, qRT-PCR to quantify candidate gene expression, and Seahorse assay to assess mitochondrial function. Insulin granule density, mitochondrial density, and mitochondrial DNA ratio were similar between groups. However, islets from WSD/WSD male and female offspring had increased expression of transcripts known to facilitate stimulus-secretion coupling and changes in the expression of cell stress genes. Seahorse assay revealed increased spare respiratory capacity in islets from WSD/WSD male offspring. Overall, these results show that maternal WSD feeding confers changes to genes governing insulin secretory coupling and results in insulin hypersecretion as early as the postweaning period. The results suggest a maternal diet leads to early adaptation and developmental programming in offspring islet genes that may underlie future ß-cell dysfunction.NEW & NOTEWORTHY Programed adaptations in islets in response to maternal WSD exposure may alter ß-cell response to metabolic stress in offspring. We show that islets from maternal WSD-exposed offspring hypersecrete insulin, possibly due to increased components of stimulus-secretion coupling. These findings suggest that islet hyperfunction is programed by maternal diet, and changes can be detected as early as the postweaning period in nonhuman primate offspring.

Asunto(s)

Diabetes Mellitus Tipo 2 , Islotes Pancreáticos , Embarazo , Animales , Masculino , Femenino , Humanos , Insulina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Dieta Occidental/efectos adversos , Primates/metabolismo , Expresión Génica , Islotes Pancreáticos/metabolismo

RESUMEN

Cellular exposure to free fatty acids (FFAs) is implicated in the pathogenesis of obesity-associated diseases. However, there are no scalable approaches to comprehensively assess the diverse FFAs circulating in human plasma. Furthermore, assessing how FFA-mediated processes interact with genetic risk for disease remains elusive. Here, we report the design and implementation of fatty acid library for comprehensive ontologies (FALCON), an unbiased, scalable, and multimodal interrogation of 61 structurally diverse FFAs. We identified a subset of lipotoxic monounsaturated fatty acids associated with decreased membrane fluidity. Furthermore, we prioritized genes that reflect the combined effects of harmful FFA exposure and genetic risk for type 2 diabetes (T2D). We found that c-MAF-inducing protein (CMIP) protects cells from FFA exposure by modulating Akt signaling. In sum, FALCON empowers the study of fundamental FFA biology and offers an integrative approach to identify much needed targets for diverse diseases associated with disordered FFA metabolism.

Asunto(s)

Diabetes Mellitus Tipo 2 , Ácidos Grasos no Esterificados , Humanos , Ácidos Grasos no Esterificados/metabolismo , Ácidos Grasos , Transducción de Señal , Biología

RESUMEN

Background: The pathogenesis of diabetes mellitus is mediated mainly by oxidative stress produced by damaged pancreatic ß-cells. We identified that an ethyl-acetate fraction (EA) from a cinnamon-cortex extract (CCE) is rich in flavonoid, and showed no toxicity to ß cells. Objective: In this study, we evaluated the pharmacologic activities of EA on pancreatic ß cells using a model of oxidative stress induced by H2O2 or alloxan. Results: The results showed that EA could significantly reduce reactive oxygen (ROS) accumulation to improve the survival of cells. Western blot showed that EA treatment upregulated expression of nuclear factor erythroid 2 related factor 2, heme oxygenase-1, and gamma glutamylcysteine synthetase. The same model study found that EA also can protect ß cells against the apoptosis induced by oxidative stress. Furthermore, EA can enhance insulin secretion in rat and mouse ß cell lines treated or not with alloxan or H2O2. The expression of the insulin transcription factor PDX-1 increased in an EA concentration-dependent manner. At last, the major functional compounds of EA analysis showed that three compounds, cinnamyl alcohol, coumarin, and cinnamic acid, had similar effects as EA. Conclusions: In sum, our data suggested that EA fraction from CCE can protect ß cells from oxidative stress, and increase insulin secretion to improve the function of ß cells. This function might be due to these three compounds found in EA. Our findings provide a theoretical basis and functional molecules for the use of CCE against diabetes mellitus.

RESUMEN

The prevalence of type 2 diabetes (T2D) is increasing worldwide. Decreased nitric oxide (NO) bioavailability is involved in the pathophysiology of T2D and its complications. L-citrulline (Cit), a precursor of NO production, has been suggested as a novel therapeutic agent for T2D. Available data from human and animal studies indicate that Cit supplementation in T2D increases circulating levels of Cit and L-arginine while decreasing circulating glucose and free fatty acids and improving dyslipidemia. The underlying mechanisms for these beneficial effects of Cit include increased insulin secretion from the pancreatic ß cells, increased glucose uptake by the skeletal muscle, as well as increased lipolysis and ß-oxidation, and decreased glyceroneogenesis in the adipose tissue. Thus, Cit has antihyperglycemic, antidyslipidemic, and antioxidant effects and has the potential to be used as a new therapeutic agent in the management of T2D. This review summarizes available literature from human and animal studies to explore the effects of Cit on metabolic parameters in T2D. It also discusses the possible mechanisms underlying Cit-induced improved metabolic parameters in T2D.

Asunto(s)

Diabetes Mellitus Tipo 2 , Animales , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Citrulina/metabolismo , Citrulina/farmacología , Citrulina/uso terapéutico , Arginina , Músculo Esquelético/metabolismo , Hipoglucemiantes/uso terapéutico

RESUMEN

Thioredoxin interacting protein (TXNIP) is a potential drug target for type 2 diabetes mellitus (T2DM) treatment. A series of quinazoline derivatives were designed, synthesised, and evaluated to inhibit TXNIP expression and protect from palmitate (PA)-induced ß cell injury. In vitro cell viability assay showed that compounds D-2 and C-1 could effectively protect ß cell from PA-induced apoptosis, and subsequent results showed that these two compounds decreased TXNIP expression by accelerating its protein degradation. Mechanistically, compounds D-2 and C-1 reduced intracellular reactive oxygen species (ROS) production and modulated TXNIP-NLRP3 inflammasome signalling, and thus alleviating oxidative stress injury and inflammatory response under PA insult. Besides, these two compounds were predicted to possess better drug-likeness properties using SwissADME. The present study showed that compounds D-2 and C-1, especially compound D-2, were potent pancreatic ß cell protective agents to inhibit TXNIP expression and might serve as promising lead candidates for the treatment of T2DM.

Asunto(s)

Diabetes Mellitus Tipo 2 , Proteína con Dominio Pirina 3 de la Familia NLR , Humanos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Línea Celular , Inflamasomas/metabolismo , Inflamasomas/farmacología , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Portadoras/metabolismo , Proteínas Portadoras/farmacología

RESUMEN

MODY3 is a monogenic hereditary form of diabetes caused by mutations in the transcription factor HNF1A. The patients progressively develop hyperglycemia due to perturbed insulin secretion, but the pathogenesis is unknown. Using patient-specific hiPSCs, we recapitulate the insulin secretion sensitivity to the membrane depolarizing agent sulfonylurea commonly observed in MODY3 patients. Unexpectedly, MODY3 patient-specific HNF1A+/R272C ß cells hypersecrete insulin both in vitro and in vivo after transplantation into mice. Consistently, we identified a trend of increased birth weight in human HNF1A mutation carriers compared with healthy siblings. Reduced expression of potassium channels, specifically the KATP channel, in MODY3 ß cells, increased calcium signaling, and rescue of the insulin hypersecretion phenotype by pharmacological targeting ATP-sensitive potassium channels or low-voltage-activated calcium channels suggest that more efficient membrane depolarization underlies the hypersecretion of insulin in MODY3 ß cells. Our findings identify a pathogenic mechanism leading to ß cell failure in MODY3.

Asunto(s)

Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Humanos , Ratones , Animales , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Diabetes Mellitus Tipo 2/genética , Fenotipo

RESUMEN

Type 2 diabetes (T2D) is a global health challenge with increased morbidity and mortality rates yearly. Herbal medicine has provided an alternative approach to treating T2D with limited access to formal healthcare. Tectona grandis is being used traditionally in the treatment of diabetes. The present study investigated the antidiabetic potential of T. grandis leaves in different solvent extractions, and the crude extract that demonstrated the best activity was further fractionated through solvent-solvent partitioning. The ethyl acetate fraction of the ethanol crude extract showed the best antidiabetic activity in inhibiting α-glucosidase, delaying glucose absorption at the small intestine's lumen, and enhancing the muscle's postprandial glucose uptake. The ethyl acetate fraction was further elucidated for its ability to reduce hyperglycemia in diabetic rats. The ethyl acetate fraction significantly reduced high blood glucose levels in diabetic rats with concomitant modulation in stimulated insulin secretions through improved pancreatic ß-cell function, insulin sensitivity by increasing liver glycogen content, and reduced elevated levels of liver glucose-6-phosphatase activity. These activities could be attributed to the phytochemical constituents of the plant.

Asunto(s)

Acetatos , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Hiperglucemia , Animales , Ratas , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Estreptozocina , Glucosa , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Experimental/tratamiento farmacológico , Hiperglucemia/tratamiento farmacológico , Fructosa , Solventes

RESUMEN

A central goal of physiological research is the understanding of cell-specific roles of disease-associated genes. Cre-mediated recombineering is the tool of choice for cell type-specific analysis of gene function in preclinical models. In the type 1 diabetes (T1D) research field, multiple lines of nonobese diabetic (NOD) mice have been engineered to express Cre recombinase in pancreatic ß cells using insulin promoter fragments, but tissue promiscuity remains a concern. Constitutive Ins1tm1.1(cre)Thor (Ins1Cre) mice on the C57/bl6-J background have high ß-cell specificity with no reported off-target effects. We explored whether NOD:Ins1Cre mice could be used to investigate ß-cell gene deletion in T1D disease modeling. We studied wild-type (Ins1WT/WT), Ins1 heterozygous (Ins1Cre/WT or Ins1Neo/WT), and Ins1 null (Ins1Cre/Neo) littermates on a NOD background. Female Ins1Neo/WT mice exhibited significant protection from diabetes, with further near-complete protection in Ins1Cre/WT mice. The effects of combined neomycin and Cre knockin in Ins1Neo/Cre mice were not additive to the Cre knockin alone. In Ins1Neo/Cre mice, protection from diabetes was associated with reduced insulitis at age 12 weeks. Collectively, these data confirm previous reports that loss of Ins1 alleles protects NOD mice from diabetes development and demonstrates, for the first time, that Cre itself may have additional protective effects. This has important implications for the experimental design and interpretation of preclinical T1D studies using ß-cell-selective Cre in NOD mice.

Asunto(s)

Diabetes Mellitus Tipo 1 , Dosificación de Gen , Células Secretoras de Insulina , Insulina , Animales , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/prevención & control , Femenino , Insulina/genética , Células Secretoras de Insulina/metabolismo , Integrasas , Ratones , Ratones Endogámicos NOD , Neomicina/metabolismo

RESUMEN

Perfluorooctanoic acid (PFOA), a widely used chemical substance, causes an increased risk of human type 2 diabetes (T2D), but its underlying mechanism is not well elucidated. The aim of the present study was to investigate whether PFOA regulates the functions of pancreatic ß cells, which are specialized for the biosynthesis and secretion of insulin. The treatment of the mouse pancreatic ß cell line (MIN6 cells) with PFOA caused a time- and dose-dependent inhibition of cell viability in CCK-8 assays. Annexin V/PI and TUNEL staining results confirmed that exposure to a high PFOA dose (500 µM) promoted apoptosis of ß cells, while a low dose (300 µM) had no effects on ß cell survival. PFOA treatment, even at a low dose, diminished glucose-stimulated insulin secretion (GSIS) in both primary islet perfusion and MIN6 cell experiments. RNA-sequencing data showed significantly increased expression of endoplasmic reticulum (ER) stress-associated genes, with tribbles homolog 3 (Trib3) ranking first among the altered genes. The activation of ER stress pathways was verified by qRT-PCR assays, and the ATF4/CHOP/TRIB3 pathway contributed to PFOA-induced ß cell damage. The inhibition of TRIB3 expression significantly protected MIN6 cells from PFOA-induced GSIS defects and apoptosis by ameliorating ER stress. These findings reveal a link between ER stress and PFOA-induced ß cell defects, opening up a new set of questions about the pathogenesis of T2D due to environmental chemicals.

Asunto(s)

Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Animales , Humanos , Ratones , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismo , Factor de Transcripción Activador 4/farmacología , Apoptosis , Proteínas de Ciclo Celular/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Estrés del Retículo Endoplásmico , Glucosa/metabolismo , Proteínas Serina-Treonina Quinasas , Proteínas Represoras/genética