Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 136
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Biomater Adv ; 164: 213980, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39126900

RESUMEN

New therapeutic approaches to treat type 1 diabetes mellitus relies on pancreatic islet transplantation. Here, developing immuno-isolation strategies is essential to eliminate the need for systemic immunosuppression after pancreatic islet grafts. A solution is the macro-encapsulation of grafts in semipermeable matrixes with a double function: separating islets from host immune cells and facilitating the diffusion of insulin, glucose, and other metabolites. This study aims to synthesize and characterize different types of gelatin-collagen matrixes to prepare a macro-encapsulation device for pancreatic islets that fulfill these functions. While natural polymers exhibit superior biocompatibility compared to synthetic ones, their mechanical properties are challenging to reproduce. To address this issue, we conducted a comparative analysis between photo-crosslinked gelatin matrixes and chemically crosslinked collagen matrixes. We show that the different crosslinkers and polymerization methods influence the survival and glucose-stimulated insulin production of pancreatic ß cells (INS1) in vitro, as well as the in vitro and in vivo stability of the matrix and the immuno-isolation in vivo. Among the matrixes, the stiff multilayer GelMA matrixes (8.5 kPa), fabricated by digital light processing, were the best suited for pancreatic ß cells macro-encapsulation regarding these parameters. Within the alveoli of this matrix, pancreatic ß cells spontaneously formed aggregates.


Asunto(s)
Gelatina , Células Secretoras de Insulina , Trasplante de Islotes Pancreáticos , Células Secretoras de Insulina/metabolismo , Animales , Trasplante de Islotes Pancreáticos/métodos , Gelatina/química , Ratas , Colágeno/metabolismo , Insulina/metabolismo , Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 1/metabolismo , Supervivencia Celular , Humanos , Materiales Biocompatibles , Glucosa/metabolismo
2.
Diabetes Obes Metab ; 26(10): 4147-4164, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39044309

RESUMEN

Obesity has increased dramatically worldwide. Being overweight or obese can lead to various conditions, including dyslipidaemia, hypertension, glucose intolerance and metabolic syndrome (MetS), which may further lead to type 2 diabetes mellitus (T2DM). Previous studies have identified a link between ß-cell dysfunction and the severity of MetS, with multiple organs and tissues affected. Identifying the associations between pancreatic ß-cell dysfunction and organs is critical. Research has focused on the interaction between the liver, gut and pancreatic ß-cells. However, the mechanisms and related core targets are still not perfectly elucidated. The aims of this review were to summarize the mechanisms of ß-cell dysfunction and to explore the potential pathogenic pathways and targets that connect the liver, gut, adipose tissue, muscle, and brain to pancreatic ß-cell dysfunction.


Asunto(s)
Tejido Adiposo , Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Hígado , Obesidad , Humanos , Células Secretoras de Insulina/fisiología , Células Secretoras de Insulina/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Diabetes Mellitus Tipo 2/metabolismo , Tejido Adiposo/metabolismo , Tejido Adiposo/fisiopatología , Obesidad/fisiopatología , Obesidad/metabolismo , Obesidad/complicaciones , Hígado/metabolismo , Síndrome Metabólico/fisiopatología , Síndrome Metabólico/metabolismo , Encéfalo/fisiopatología , Encéfalo/metabolismo , Animales , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatología
3.
Front Endocrinol (Lausanne) ; 15: 1344729, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38904034

RESUMEN

Cuproptosis, a recently discovered form of cell death, stems from an overabundance of copper ions infiltrating mitochondria. These ions directly engage lipoylated proteins, prompting their oligomerization and subsequent loss of iron-sulfur clusters. This sequence induces proteotoxic stress, ultimately culminating in cell death. Type 2 diabetes, a chronic metabolic disorder resulting from a complex interplay of genetic and environmental factors, has not yet been fully understood in terms of its etiology and pathogenesis. Intricately, it is linked to various modalities of cell death, including mitochondrial autophagy, apoptosis, pyroptosis, and ferroptosis. Studies have discovered impaired copper metabolism in individuals with Type 2 diabetes, hinting at a unique role for copper homeostasis in the progression of the disease. To this end, the present research aims to delineate the potential correlation between cuproptosis and Type 2 diabetes by exhaustively reviewing the existing literature. By synthesizing relevant research on cuproptosis, the paper intends to lay the groundwork for a thorough exploration of the pathogenesis of Type 2 diabetes and the development of targeted therapeutic interventions. The ultimate objective is to facilitate a deeper understanding of Type 2 diabetes and to identify novel therapeutic strategies associated with cuproptosis.


Asunto(s)
Cobre , Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Cobre/metabolismo , Animales , Mitocondrias/metabolismo , Muerte Celular
4.
Physiol Rep ; 12(11): e16091, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38862270

RESUMEN

Sildenafil, a phosphodiesterase-5 (PDE5) inhibitor, has been shown to improve insulin sensitivity in animal models and prediabetic patients. However, its other metabolic effects remain poorly investigated. This study examines the impact of sildenafil on insulin secretion in MIN6-K8 mouse clonal ß cells. Sildenafil amplified insulin secretion by enhancing Ca2+ influx. These effects required other depolarizing stimuli in MIN6-K8 cells but not in KATP channel-deficient ß cells, which were already depolarized, indicating that sildenafil-amplified insulin secretion is depolarization-dependent and KATP channel-independent. Interestingly, sildenafil-amplified insulin secretion was inhibited by pharmacological inhibition of R-type channels, but not of other types of voltage-dependent Ca2+ channels (VDCCs). Furthermore, sildenafil-amplified insulin secretion was barely affected when its effect on cyclic GMP was inhibited by PDE5 knockdown. Thus, sildenafil stimulates insulin secretion and Ca2+ influx through R-type VDCCs independently of the PDE5/cGMP pathway, a mechanism that differs from the known pharmacology of sildenafil and conventional insulin secretory pathways. Our results reposition sildenafil as an insulinotropic agent that can be used as a potential antidiabetic medicine and a tool to elucidate the novel mechanism of insulin secretion.


Asunto(s)
Calcio , Secreción de Insulina , Células Secretoras de Insulina , Insulina , Inhibidores de Fosfodiesterasa 5 , Citrato de Sildenafil , Citrato de Sildenafil/farmacología , Animales , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Ratones , Secreción de Insulina/efectos de los fármacos , Inhibidores de Fosfodiesterasa 5/farmacología , Calcio/metabolismo , Insulina/metabolismo , Línea Celular
5.
J Nat Med ; 78(4): 849-862, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38724866

RESUMEN

In this study, 14 abietene and pimarene diterpenoids were isolated from the woods of Agathis dammara. Among them, 4 new compounds, dammarone A-C and dammaric acid A (1-4), were firstly reported, respectively. The structure of the new compounds was determined by HR ESI-MS and 1D/2D NMR spectroscopy, and their absolute configuration was determined by electronic circular dichroism (ECD) exciton chirality method. The hypoglycemic effect of all compounds was evaluated by transgenic zebrafish model, and the structure-activity relationship was discussed. Hinokione (7, HO) has low toxicity and significant hypoglycemic effects on zebrafish, the mechanism is mainly by promoting the differentiation of zebrafish pancreatic endocrine precursor cells (PEP cells) into ß cells, thereby promoting the regeneration of pancreatic ß cells.


Asunto(s)
Diterpenos , Hipoglucemiantes , Células Secretoras de Insulina , Regeneración , Pez Cebra , Animales , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Diterpenos/química , Diterpenos/farmacología , Diterpenos/aislamiento & purificación , Hipoglucemiantes/farmacología , Hipoglucemiantes/química , Hipoglucemiantes/aislamiento & purificación , Estructura Molecular , Regeneración/efectos de los fármacos , Relación Estructura-Actividad , Madera/química , Animales Modificados Genéticamente , Thymelaeaceae/química
6.
Sci Rep ; 14(1): 12521, 2024 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-38822085

RESUMEN

Sirtuin1 (SIRT1) activity decreases the tuberous sclerosis complex 2 (TSC2) lysine acetylation status, inhibiting the mechanistic target of rapamycin complex 1 (mTORC1) signalling and concomitantly, activating autophagy. This study analyzes the role of TSC2 acetylation levels in its translocation to the lysosome and the mitochondrial turnover in both mouse embryonic fibroblast (MEF) and in mouse insulinoma cells (MIN6) as a model of pancreatic ß cells. Resveratrol (RESV), an activator of SIRT1 activity, promotes TSC2 deacetylation and its translocation to the lysosome, inhibiting mTORC1 activity. An improvement in mitochondrial turnover was also observed in cells treated with RESV, associated with an increase in the fissioned mitochondria, positive autophagic and mitophagic fluxes and an enhancement of mitochondrial biogenesis. This study proves that TSC2 in its deacetylated form is essential for regulating mTORC1 signalling and the maintenance of the mitochondrial quality control, which is involved in the homeostasis of pancreatic beta cells and prevents from several metabolic disorders such as Type 2 Diabetes Mellitus.


Asunto(s)
Lisosomas , Mitocondrias , Proteína 2 del Complejo de la Esclerosis Tuberosa , Animales , Ratones , Acetilación , Autofagia , Línea Celular Tumoral , Fibroblastos/metabolismo , Células Secretoras de Insulina/metabolismo , Lisosomas/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Mitocondrias/metabolismo , Transporte de Proteínas , Resveratrol/farmacología , Transducción de Señal , Sirtuina 1/metabolismo , Proteína 2 del Complejo de la Esclerosis Tuberosa/metabolismo , Proteína 2 del Complejo de la Esclerosis Tuberosa/genética
7.
Nutrients ; 16(7)2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-38613031

RESUMEN

In diabetes, pancreatic ß-cells gradually lose their ability to secrete insulin with disease progression. ß-cell dysfunction is a contributing factor to diabetes severity. Recently, islet cell heterogeneity, exemplified by ß-cell dedifferentiation and identified in diabetic animals, has attracted attention as an underlying molecular mechanism of ß-cell dysfunction. Previously, we reported ß-cell dedifferentiation suppression by calorie restriction, not by reducing hyperglycemia using hypoglycemic agents (including sodium-glucose cotransporter inhibitors), in an obese diabetic mice model (db/db). Here, to explore further mechanisms of the effects of food intake on ß-cell function, db/db mice were fed either a high-carbohydrate/low-fat diet (db-HC) or a low-carbohydrate/high-fat diet (db-HF) using similar calorie restriction regimens. After one month of intervention, body weight reduced, and glucose intolerance improved to a similar extent in the db-HC and db-HF groups. However, ß-cell dedifferentiation did not improve in the db-HC group, and ß-cell mass compensatory increase occurred in this group. More prominent fat accumulation occurred in the db-HC group livers. The expression levels of genes related to lipid metabolism, mainly regulated by peroxisome proliferator-activated receptor α and γ, differed significantly between groups. In conclusion, the fat/carbohydrate ratio in food during calorie restriction in obese mice affected both liver lipid metabolism and ß-cell dedifferentiation.


Asunto(s)
Restricción Calórica , Diabetes Mellitus Experimental , Animales , Ratones , Ratones Obesos , Dieta Alta en Grasa/efectos adversos , Desdiferenciación Celular , Dieta Baja en Carbohidratos , Hígado , Carbohidratos , Obesidad
8.
Cells ; 13(7)2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38607078

RESUMEN

Insulin-producing pancreatic ß cells play a crucial role in the regulation of glucose homeostasis, and their failure is a key event for diabetes development. Prolonged exposure to palmitate in the presence of elevated glucose levels, termed gluco-lipotoxicity, is known to induce ß cell apoptosis. Autophagy has been proposed to be regulated by gluco-lipotoxicity in order to favor ß cell survival. However, the role of palmitate metabolism in gluco-lipotoxcity-induced autophagy is presently unknown. We therefore treated INS-1 cells for 6 and 24 h with palmitate in the presence of low and high glucose concentrations and then monitored autophagy. Gluco-lipotoxicity induces accumulation of LC3-II levels in INS-1 at 6 h which returns to basal levels at 24 h. Using the RFP-GFP-LC3 probe, gluco-lipotoxicity increased both autophagosomes and autolysosmes structures, reflecting early stimulation of an autophagy flux. Triacsin C, a potent inhibitor of the long fatty acid acetyl-coA synthase, completely prevents LC3-II formation and recruitment to autophagosomes, suggesting that autophagic response requires palmitate metabolism. In contrast, etomoxir and bromo-palmitate, inhibitors of fatty acid mitochondrial ß-oxidation, are unable to prevent gluco-lipotoxicity-induced LC3-II accumulation and recruitment to autophagosomes. Moreover, bromo-palmitate and etomoxir potentiate palmitate autophagic response. Even if gluco-lipotoxicity raised ceramide levels in INS-1 cells, ceramide synthase 4 overexpression does not potentiate LC3-II accumulation. Gluco-lipotoxicity also still stimulates an autophagic flux in the presence of an ER stress repressor. Finally, selective inhibition of sphingosine kinase 1 (SphK1) activity precludes gluco-lipotoxicity to induce LC3-II accumulation. Moreover, SphK1 overexpression potentiates autophagic flux induced by gluco-lipotxicity. Altogether, our results indicate that early activation of autophagy by gluco-lipotoxicity is mediated by SphK1, which plays a protective role in ß cells.


Asunto(s)
Células Secretoras de Insulina , Fosfotransferasas (Aceptor de Grupo Alcohol) , Autofagia , Compuestos Epoxi , Glucosa/metabolismo , Células Secretoras de Insulina/metabolismo , Palmitatos/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Línea Celular , Animales , Ratas
9.
Islets ; 16(1): 2339558, 2024 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-38607959

RESUMEN

BACKGROUND: Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid receptors 2 and 3 (FFA2 and FFA3). As these are G-protein coupled receptors (GPCRs), they have potential therapeutic value as targets for treating type 2 diabetes (T2D). The exact mechanism by which these receptors regulate insulin secretion and other aspects of pancreatic ß cell function is unclear. It has been reported that glucose-dependent release of acetate from pancreatic ß cells negatively regulates glucose stimulated insulin secretion. While these data raise the possibility of acetate's potential autocrine action on these receptors, these findings have not been independently confirmed, and multiple concerns exist with this observation, particularly the lack of specificity and precision of the acetate detection methodology used. METHODS: Using Min6 cells and mouse islets, we assessed acetate and pyruvate production and secretion in response to different glucose concentrations, via liquid chromatography mass spectrometry. RESULTS: Using Min6 cells and mouse islets, we showed that both intracellular pyruvate and acetate increased with high glucose conditions; however, intracellular acetate level increased only slightly and exclusively in Min6 cells but not in the islets. Further, extracellular acetate levels were not affected by the concentration of glucose in the incubation medium of either Min6 cells or islets. CONCLUSIONS: Our findings do not substantiate the glucose-dependent release of acetate from pancreatic ß cells, and therefore, invalidate the possibility of an autocrine inhibitory effect on glucose stimulated insulin secretion.


Asunto(s)
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Animales , Ratones , Acetatos , Glucosa , Ácido Pirúvico
10.
Cell Metab ; 36(6): 1237-1251.e4, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38513648

RESUMEN

Pancreatic ß cells actively respond to glucose fluctuations through regulating insulin processing and secretion. However, how this process is elaborately tuned in circumstance of variable microenvironments as well as ß cell-intrinsic states and whether its dysfunction links to metabolic diseases remain largely elusive. Here, we show that the cytosolic pH (pHc) in ß cells is increased upon glucose challenge, which can be sensed by Smad5 via its nucleocytoplasmic shuttling. Lesion of Smad5 in ß cells results in hyperglycemia and glucose intolerance due to insulin processing and secretion deficiency. The role of Smad5 in regulating insulin processing and secretion attributes to its non-canonical function by regulating V-ATPase activity for granule acidification. Genetic mutation of Smad5 or administration of alkaline water to mirror cytosolic alkalization ameliorated glucose intolerance in high-fat diet (HFD)-treated mice. Collectively, our findings suggest that pHc is a direct nexus in linking environmental cues with insulin processing and secretion in ß cells.


Asunto(s)
Citosol , Secreción de Insulina , Células Secretoras de Insulina , Insulina , Ratones Endogámicos C57BL , Animales , Células Secretoras de Insulina/metabolismo , Concentración de Iones de Hidrógeno , Citosol/metabolismo , Ratones , Insulina/metabolismo , Masculino , Dieta Alta en Grasa , Intolerancia a la Glucosa/metabolismo , Glucosa/metabolismo , Humanos
11.
Reprod Biol ; 24(1): 100850, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38262267

RESUMEN

Gestational diabetes mellitus (GDM) is a prevalent metabolic disturbance in pregnancy. This article investigated the correlations between serum IGF1R and ATG7 with insulin resistance (IR) in GDM patients. Firstly, 100 GDM patients and 100 healthy pregnant women were selected as study subjects. The levels of serum IGF1, IGF1R, and ATG7 and their correlations with the insulin resistance index homeostasis model assessment of insulin resistance (HOMA-IR) were measured and analyzed by ELISA and Pearson. Additionally, in mouse pancreatic ß cells, IGF1R, ATG7, Beclin-1, and LC3-II/LC3-I levels, cell viability/apoptosis, and insulin level were assessed by western blot, CCK-8, flow cytometry, and ELISA. The GDM group exhibited obviously raised serum IGF1 level and diminished serum IGF1R/ATG7 levels. The IGF1 level was positively correlated with HOMA-IR, while IGF1R/ATG7 levels were negatively correlated with HOMA-IR in GDM patients. Collectively, IGF1R stimulated cell viability, suppressed apoptosis, amplified insulin secretion, and increased ATG7 expression to induce cell autophagy, which could be partially averted by ATG7 silencing.


Asunto(s)
Diabetes Gestacional , Resistencia a la Insulina , Células Secretoras de Insulina , Animales , Ratones , Embarazo , Humanos , Femenino , Diabetes Gestacional/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/química , Células Secretoras de Insulina/metabolismo , Glucemia/análisis , Glucemia/metabolismo , Insulina , Receptor IGF Tipo 1/metabolismo
12.
Rev Endocr Metab Disord ; 25(2): 259-278, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38048021

RESUMEN

Undernutrition is still a recurring nutritional problem in low and middle-income countries. It is directly associated with the social and economic sphere, but it can also negatively impact the health of the population. In this sense, it is believed that undernourished individuals may be more susceptible to the development of non-communicable diseases, such as diabetes mellitus, throughout life. This hypothesis was postulated and confirmed until today by several studies that demonstrate that experimental models submitted to protein undernutrition present alterations in glycemic homeostasis linked, in part, to the reduction of insulin secretion. Therefore, understanding the changes that lead to a reduction in the secretion of this hormone is essential to prevent the development of diabetes in undernourished individuals. This narrative review aims to describe the main molecular changes already characterized in pancreatic ß cells that will contribute to the reduction of insulin secretion in protein undernutrition. So, it will provide new perspectives and targets for postulation and action of therapeutic strategies to improve glycemic homeostasis during this nutritional deficiency.


Asunto(s)
Diabetes Mellitus Tipo 2 , Diabetes Mellitus , Desnutrición , Trastornos Nutricionales , Humanos , Secreción de Insulina , Insulina/metabolismo
13.
J Physiol Biochem ; 80(1): 175-188, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38032518

RESUMEN

Lipotoxicity-induced pancreatic ß cell damage is a strong predictor of type 2 diabetes mellitus (T2DM). Our previous work showed that Caveolin-1 (Cav-1) depletion decreased ß-cell apoptosis and improved ß-cell viability. Further microarray analysis indicated significant changes in the expression of genes related to fatty acid metabolism and inflammation. The objective of this study was to explore the role of Cav-1 in intracellular lipid accumulation and inflammation in ß cells under lipotoxic conditions. Here, we established a ß-cell-specific Cav-1 knockout (ß-Cav-1 KO) mouse model and a CAV-1 depleted ß cell line (NIT-1). We found that Cav-1 silencing significantly reduced palmitate (PA)-induced intracellular triglyceride (TG) accumulation and decreased proinflammatory factor expression in both the mouse and cell models. Further mechanistic investigation revealed that amelioration of lipid metabolism was achieved through the downregulation of lipogenic markers (SREBP-1c, FAS and ACC) and upregulation of a fatty acid oxidation marker (CPT-1). Meanwhile, decrease of inflammatory cytokines (IL-6, TNF-α, and IL-1ß) secretion was found with the involvement of the IKKß/NF-κB signaling pathways. Our findings suggest that Cav-1 is of considerable importance in regulating lipotoxicity-induced ß-cell intracellular lipid accumulation and inflammation.


Asunto(s)
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Ratones , Animales , Palmitatos/metabolismo , Palmitatos/farmacología , Células Secretoras de Insulina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Caveolina 1/genética , Inflamación/metabolismo
14.
Inflamm Regen ; 43(1): 60, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-38087385

RESUMEN

Metabolism in each organ of multi-organ organisms, including humans, is regulated in a coordinated manner to dynamically maintain whole-body homeostasis. Metabolic information exchange among organs/tissues, i.e., inter-organ communication, which is necessary for this purpose, has been a subject of ongoing research. In particular, it has become clear that metabolism of energy, glucose, lipids, and amino acids is dynamically regulated at the whole-body level mediated by the nervous system, including afferent, central, and efferent nerves. These findings imply that the central nervous system obtains metabolic information from peripheral organs at all times and sends signals selectively to peripheral organs/tissues to maintain metabolic homeostasis, and that the liver plays an important role in sensing and transmitting information on the metabolic status of the body. Furthermore, the utilization of these endogenous mechanisms is expected to lead to the development of novel preventive/curative therapies for metabolic diseases such as diabetes and obesity.(This is a summarized version of the subject matter presented at Symposium 7 presented at the 43rd Annual Meeting of the Japanese Society of Inflammation and Regeneration.).

15.
Bio Protoc ; 13(21): e4868, 2023 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-37969764

RESUMEN

Pancreatic islet ß cells preferentially secrete insulin toward the plasma membrane, making contact with the capillary extracellular matrix (ECM). Isolated islets separated from the exocrine acinar cells are the best system for cell biology studies of primary ß cells, whereas isolated islets lose their capillary network during ex vivo culture. Providing the appropriate extracellular signaling by attaching islets to vascular ECM-coated surfaces can restore the polarized insulin secretion toward the ECM. The guided secretion toward ECM-coated glass coverslips provides a good model for recording insulin secretion in real time to study its regulation. Additionally, ß cells attached to the ECM-coated coverslips are suitable for confocal live imaging of subcellular components including adhesion molecules, cytoskeleton, and ion channels. This procedure is also compatible for total internal reflection fluorescence (TIRF) microscopy, which provides optimal signal-to-noise ratio and high spatial precision of structures close to the plasma membrane. In this article, we describe the optimized protocol for vascular ECM-coating of glass coverslips and the process of attachment of isolated mouse islets on the coverslip. This preparation is compatible with any high-resolution microscopy of live primary ß cells. Key features • Optimized coating procedure to attach isolated islets, compatible for both confocal and TIRF microscopy. • The ECM-coated glass coverslip functions as the artificial capillary surface to guide secretion toward the coated surface for optimal imaging of secretion events. • Shows the process of islets attachment to the ECM-coated surface in a 6-day ex vivo culture.

16.
Environ Sci Pollut Res Int ; 30(59): 123286-123308, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37981611

RESUMEN

This study investigated the anti-hyperglycemic action of mango seed kernel extract (MKE) and various mechanisms involved in its actions to improve pancreatic ß cells and hepatic carbohydrate metabolism in diabetic rats. An intraperitoneal injection of 60 mg/kg of streptozotocin (STZ) followed by 30 consecutive days of treatment with MKE (250, 500, and 1000 mg/kg body weight) was used to establish a study group of diabetic rats. Using liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) for identification, 26 chemical compounds were found in MKE and the high-performance liquid chromatography (HPLC) analysis of the MKE also revealed the existence of mangiferin, gallic acid, and quercetin. The results confirmed that in each diabetes-affected rat, MKE mitigated the heightened levels of fasting blood glucose, diabetic symptoms, glucose intolerance, total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C). As demonstrated by a remarkable increment in serum and pancreatic insulin, the diabetic pancreatic ß cell function was potentiated by treating with MKE. The effect of MKE on diabetic pancreatic apoptosis clearly reduced the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells, which was related to diminished levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and Bax and an increase in Bcl-xL protein expression. Furthermore, diabetes-induced liver damage was clearly ameliorated along with a notable reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver histology. By enhancing anti-oxidant superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, MKE alleviated diabetes-induced pancreatic and liver oxidative damage, as demonstrated by diminished levels of malondialdehyde. In minimizing the expression levels of glucose 6-phosphatase and phosphoenolpyruvate carboxykinase-1 proteins in the diabetic liver, MKE also enhanced glycogen content and hexokinase activity. Collectively, these findings indicate that by suppressing oxidative and inflammatory processes, MKE exerts a potent anti-hyperglycemic activity in diabetic rats which serve to protect pancreatic ß cell apoptosis, enhance their function, and improve hepatic glucose metabolism.


Asunto(s)
Diabetes Mellitus Experimental , Hiperglucemia , Células Secretoras de Insulina , Mangifera , Ratas , Animales , Glucosa/metabolismo , Diabetes Mellitus Experimental/metabolismo , Espectrometría de Masas en Tándem , Glucemia/análisis , Antioxidantes/metabolismo , Hiperglucemia/metabolismo , Hígado , Apoptosis , Estrés Oxidativo , Extractos Vegetales/farmacología , Extractos Vegetales/metabolismo , Hipoglucemiantes/farmacología , Metabolismo de los Hidratos de Carbono , Colesterol/metabolismo
17.
Cell Rep ; 42(11): 113326, 2023 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-37897727

RESUMEN

Glucagon-like peptide 1 (GLP-1R) and glucose-dependent insulinotropic polypeptide (GIPR) receptors are G-protein-coupled receptors involved in glucose homeostasis. Diabetogenic conditions decrease ß-arrestin 2 (ARRB2) levels in human islets. In mouse ß cells, ARRB2 dampens insulin secretion by partially uncoupling cyclic AMP (cAMP)/protein kinase A (PKA) signaling at physiological doses of GLP-1, whereas at pharmacological doses, the activation of extracellular signal-related kinase (ERK)/cAMP-responsive element-binding protein (CREB) requires ARRB2. In contrast, GIP-potentiated insulin secretion needs ARRB2 in mouse and human islets. The GIPR-ARRB2 axis is not involved in cAMP/PKA or ERK signaling but does mediate GIP-induced F-actin depolymerization. Finally, the dual GLP-1/GIP agonist tirzepatide does not require ARRB2 for the potentiation of insulin secretion. Thus, ARRB2 plays distinct roles in regulating GLP-1R and GIPR signaling, and we highlight (1) its role in the physiological context and the possible functional consequences of its decreased expression in pathological situations such as diabetes and (2) the importance of assessing the signaling pathways engaged by the agonists (biased/dual) for therapeutic purposes.


Asunto(s)
Células Secretoras de Insulina , Ratones , Humanos , Animales , Células Secretoras de Insulina/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Insulina/metabolismo , Arrestina beta 2/metabolismo , beta-Arrestina 1/metabolismo , Glucosa/metabolismo
18.
Toxicol In Vitro ; 93: 105665, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37619648

RESUMEN

This study investigated whether scopoletin could protect INS-1 pancreatic ß cells from apoptosis and oxidative stress caused by high glucose. Cells were pretreated with glucose (5.5 or 30 mM) and then treated with 0, 5, 10, 25, or 50 µM Scopoletin. Cell viability and insulin secretion were measured in addition to ROS, TBARS, NO and antioxidant enzymes. Western blot analysis and flow cytometric assessment of apoptosis were also carried out. High glucose of 30 mM caused glucotoxicity and cell death in INS-1 pancreatic ß cells. However, 5, 10, 25 or 50 µM scopoletin increased the level of cell viability as concentrations increased. The levels of ROS, TBARS, and NO increased by high glucose were significantly decreased after scopoletin treatment. Scopoletin also raised antioxidant enzyme activities up against oxidative stress produced by high glucose. These effects influenced the apoptosis pathway, raising levels of anti-apoptotic protein, Bcl-2, and reducing levels of pro-apoptotic proteins, including JNK, Bax, cytochrome C, and caspase 9. Annexin V/propidium staining indicated that scopoletin significantly lowered high glucose-produced apoptosis. These results indicate that scopoletin can protect INS-1 pancreatic ß cells from glucotoxicity caused by high glucose and have potential as a pharmaceutical material to protect the pancreatic ß cells.


Asunto(s)
Células Secretoras de Insulina , Células Secretoras de Insulina/metabolismo , Escopoletina/farmacología , Escopoletina/metabolismo , Antioxidantes/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , Apoptosis , Estrés Oxidativo , Glucosa/toxicidad , Glucosa/metabolismo , Insulina/metabolismo
19.
Cell Tissue Res ; 394(1): 131-144, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37474621

RESUMEN

Pancreatic ß cell clusters produce insulin and play a central role in glucose homeostasis. The regenerative capacity of mammalian ß cells is limited and the loss of ß cells causes diabetes. In contrast, zebrafish ß cell clusters have a high regenerative capacity, making them an attractive model to study ß cell cluster regeneration. How zebrafish ß cell clusters regenerate, when the regeneration process is complete, and the identification of the cellular source of regeneration are fundamental questions that require investigation. Here, using larval and adult zebrafish, we demonstrate that pancreatic ß cell clusters undergo a two-step regeneration process, regenerating functionality and then ß cell numbers. Additionally, we found that all regenerating pancreatic ß cells arose from Neurod1-expressing cells and that cells from different lineages contribute to both functional and ß cell number recovery throughout their life. Furthermore, we found that during development and neogenesis, as well as regeneration, all ß cells undergo Neurod1expression in zebrafish. Together, these results shed light on the fundamental cellular mechanisms underlying ß cell cluster development, neogenesis, and regeneration.


Asunto(s)
Diabetes Mellitus , Células Secretoras de Insulina , Animales , Linaje de la Célula , Insulina , Mamíferos , Pez Cebra , Proteínas de Pez Cebra/metabolismo
20.
Acta Biomater ; 167: 38-53, 2023 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-37392934

RESUMEN

Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease characterized by autoimmune destruction of pancreatic ß cells. Transplantation of immunoisolated pancreatic islets might treat T1DM in the absence of chronic immunosuppression. Important advances have been made in the past decade as capsules can be produced that provoke minimal to no foreign body response after implantation. However, graft survival is still limited as islet dysfunction may occur due to chronic damage to islets during islet isolation, immune responses induced by inflammatory cells, and nutritional issues for encapsulated cells. This review summarizes the current challenges for promoting longevity of grafts. Possible strategies for improving islet graft longevity are also discussed, including supplementation of the intracapsular milieu with essential survival factors, promotion of vascularization and oxygenation near capsules, modulation of biomaterials, and co-transplantation of accessory cells. Current insight is that both the intracapsular as well as the extracapsular properties should be improved to achieve long-term survival of islet-tissue. Some of these approaches reproducibly induce normoglycemia for more than a year in rodents. Further development of the technology requires collective research efforts in material science, immunology, and endocrinology. STATEMENT OF SIGNIFICANCE: Islet immunoisolation allows for transplantation of insulin producing cells in absence of immunosuppression and might facilitate the use of xenogeneic cell sources or grafting of cells obtained from replenishable cell sources. However, a major challenge to date is to create a microenvironment that supports long-term graft survival. This review provides a comprehensive overview of the currently identified factors that have been demonstrated to be involved in either stimulating or reducing islet graft survival in immunoisolating devices and discussed current strategies to enhance the longevity of encapsulated islet grafts as treatment for type 1 diabetes. Although significant challenges remain, interdisciplinary collaboration across fields may overcome obstacles and facilitate the translation of encapsulated cell therapy from the laboratory to clinical application.


Asunto(s)
Diabetes Mellitus Tipo 1 , Células Secretoras de Insulina , Trasplante de Islotes Pancreáticos , Islotes Pancreáticos , Humanos , Diabetes Mellitus Tipo 1/terapia , Cápsulas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA