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2.
Transpl Int ; 37: 11900, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38304198

RESUMO

The generation of insulin-producing cells from human-induced pluripotent stem cells holds great potential for diabetes modeling and treatment. However, existing protocols typically involve incubating cells with un-physiologically high concentrations of glucose, which often fail to generate fully functional IPCs. Here, we investigated the influence of high (20 mM) versus low (5.5 mM) glucose concentrations on IPCs differentiation in three hiPSC lines. In two hiPSC lines that were unable to differentiate to IPCs sufficiently, we found that high glucose during differentiation leads to a shortage of NKX6.1+ cells that have co-expression with PDX1 due to insufficient NKX6.1 gene activation, thus further reducing differentiation efficiency. Furthermore, high glucose during differentiation weakened mitochondrial respiration ability. In the third iPSC line, which is IPC differentiation amenable, glucose concentrations did not affect the PDX1/NKX6.1 expression and differentiation efficiency. In addition, glucose-stimulated insulin secretion was only seen in the differentiation under a high glucose condition. These IPCs have higher KATP channel activity and were linked to sufficient ABCC8 gene expression under a high glucose condition. These data suggest high glucose concentration during IPC differentiation is necessary to generate functional IPCs. However, in cell lines that were IPC differentiation unamenable, high glucose could worsen the situation.


Assuntos
Células-Tronco Pluripotentes Induzidas , Células Secretoras de Insulina , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Insulina/metabolismo , Diferenciação Celular , Glucose/farmacologia , Glucose/metabolismo
3.
J Vis Exp ; (203)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38345259

RESUMO

Diabetes mellitus (DM) is caused by insufficient insulin release from the pancreatic ß-cells (Type1 DM) and insulin sensitivity in muscles, liver, and adipose tissues (Type2 DM). Insulin injection treats DM patients but leads to hypoglycemia as a side effect. Cortisol and catecholamines are released to activate glucose production from the liver to recover hypoglycemia, called counter-regulatory responses (CRR). In DM research using rodent models, glucose tolerance tests and 2-deoxy-glucose injection are used to measure insulin release and CRR, respectively. However, blood glucose concentrations change persistently during experiments, causing difficulties in assessing net insulin release and CRR. This article describes a method in which blood glucose is kept at 250 mg/dL or 50 mg/dL in conscious mice to compare the release of insulin and CRR hormones, respectively. Polyethylene tubing is implanted in the mice's carotid artery and jugular vein, and the mice are allowed to recover from the surgery. The jugular vein tubing is connected to a Hamilton syringe with a syringe pump to enable insulin or glucose infusion at a constant and variable rate. The carotid artery tubing is for blood collection. For the hyperglycemic clamp, 30% glucose is infused into the vein, and blood glucose levels are measured from the arterial blood every 5 min or 10 min. The infusion rate of 30% glucose is increased until the blood glucose level becomes 250 mg/dL. Blood is collected to measure insulin concentrations. For hypoglycemic clamp, 10 mU/kg/min insulin is infused together with 30% glucose, whose infusion rate is variable to maintain 50 mg/dL of blood glucose level. Blood is collected to measure counter-regulatory hormones when both glucose infusion and blood glucose reach a steady state. Both hyperglycemic and hypoglycemic clamps have the same surgical procedure and experimental setups. Thus, this method is useful for researchers of systemic glucose metabolism.


Assuntos
Diabetes Mellitus , Hipoglicemia , Humanos , Camundongos , Animais , Glicemia/metabolismo , Hipoglicemiantes/farmacologia , Técnica Clamp de Glucose , Hipoglicemia/metabolismo , Insulina/metabolismo , Glucose/metabolismo
4.
Ceska Slov Farm ; 72(6): 288-296, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38346906

RESUMO

Metabolic syndrome (MetS) is a symptomatic complex characterized by insulin resistance, impaired prooxidant-antioxidantbalance of the body with the development of subchronic inflammation, and dyslipidemia. The aim of the study is to investigate the effect of a complex pharmaceutical composition (CPC) (antioxidants and metabolitotropic agents), which is widely used in medical practice in Ukraine as a multivitamin complex, on experimental metabolic syndrome in rats. The effectof CPC on the correction of experimental MetS in rats, induced by a high content of carbohydrates and fats in the diet, was assessed. MetS in rats was characterized by a decrease in the sensitivity of cells to insulin, increased glucose content, and aviolation of its utilization, prooxidant-antioxidant disbalance. The results of the conducted studies indicate the positive effect of CPC, which contains ethyl esters of omega-3 acids, vitamin E, coenzyme Q10, zinc, vitamin A, biotin, and selenium, on the sensitivity of cells to insulin, glucose utilization, duration of hyperglycemia and indicators of free radical oxidation processes and antioxidant defense systems in rats with experimental MetS. These results prove the feasibility of using CPC to correct metabolic syndrome.


Assuntos
Resistência à Insulina , Síndrome Metabólica , Ratos , Animais , Síndrome Metabólica/tratamento farmacológico , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Estresse Oxidativo , Insulina/metabolismo , Insulina/farmacologia , Preparações Farmacêuticas , Glucose
5.
J Physiol Sci ; 74(1): 8, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38331728

RESUMO

The athlete's paradox phenomenon involves the accumulation of intramuscular triglycerides (IMTG) in both insulin-resistant and insulin-sensitive endurance athletes. Nevertheless, a complete understanding of this phenomenon is yet to be achieved. Recent research indicates that lactate, a common byproduct of physical activity, may increase the accumulation of IMTG in skeletal muscle. This is achieved through the activation of G protein-coupled receptor 81 (GPR81) leads to the suppression of the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) pathway. The mechanism accountable for the increase in mitochondrial content in skeletal muscle triggered by lactate remains incomprehensible. Based on current research, our objective is to explore the role of the GPR81-inhibited cAMP-PKA pathway in the aggregation of IMTG and the increase in mitochondrial content as a result of prolonged exercise. The GPR81-cAMP-PKA-signaling pathway regulates the buildup of IMTG caused by extended periods of endurance training (ET). This is likely due to a decrease in proteins related to fat breakdown and an increase in proteins responsible for fat production. It is possible that the GPR81-cAMP-PKA pathway does not contribute to the long-term increase in mitochondrial biogenesis and content, which is induced by chronic ET. Additional investigation is required to explore the possible hindrance of the mitochondrial biogenesis and content process during physical activity by the GPR81-cAMP-PKA signal.


Assuntos
Treino Aeróbico , Humanos , Ratos , Animais , Triglicerídeos , Resistência Física/fisiologia , Músculo Esquelético/metabolismo , Insulina/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Lactatos/metabolismo
6.
Cells ; 13(3)2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38334680

RESUMO

The aging process is inherently complex, involving multiple mechanisms that interact at different biological scales. The nematode Caenorhabditis elegans is a simple model organism that has played a pivotal role in aging research following the discovery of mutations extending lifespan. Longevity pathways identified in C. elegans were subsequently found to be conserved and regulate lifespan in multiple species. These pathways intersect with fundamental hallmarks of aging that include nutrient sensing, epigenetic alterations, proteostasis loss, and mitochondrial dysfunction. Here we summarize recent data obtained in C. elegans highlighting the importance of studying aging at both the tissue and temporal scale. We then focus on the neuromuscular system to illustrate the kinetics of changes that take place with age. We describe recently developed tools that enabled the dissection of the contribution of the insulin/IGF-1 receptor ortholog DAF-2 to the regulation of worm mobility in specific tissues and at different ages. We also discuss guidelines and potential pitfalls in the use of these new tools. We further highlight the opportunities that they present, especially when combined with recent transcriptomic data, to address and resolve the inherent complexity of aging. Understanding how different aging processes interact within and between tissues at different life stages could ultimately suggest potential intervention points for age-related diseases.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Insulina/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Envelhecimento/metabolismo
7.
Acta Biotheor ; 72(1): 2, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38334878

RESUMO

The calcium signals regulate the production and secretion of many signaling molecules like inositol trisphosphate ([Formula: see text]) and adenosine triphosphate (ATP) in various cells including pancreatic [Formula: see text]-cells. The calcium signaling mechanisms regulating [Formula: see text], ATP and insulin responsible for various functions of [Formula: see text]-cells are still not well understood. Any disturbance in these mechanisms can alter the functions of [Formula: see text]-cells leading to diabetes and metabolic disorders. Therefore, a mathematical model is proposed by incorporating the reaction-diffusion equation for calcium dynamics and a system of first-order differential equations for [Formula: see text], ATP-production and insulin secretion with initial and boundary conditions. The model incorporates the temporal dependence of [Formula: see text]-production and degradation, ATP production and insulin secretion on calcium dynamics in a [Formula: see text]-cell. The piecewise linear finite element method has been used for the spatial dimension and the Crank-Nicolson scheme for the temporal dimension to obtain numerical results. The effect of changes in source influxes and buffers on calcium dynamics and production of [Formula: see text], ATP and insulin levels in a [Formula: see text]-cell has been analyzed. It is concluded that the dysfunction of source influx and buffers can cause significant variations in calcium levels and dysregulation of [Formula: see text], ATP and insulin production, which can lead to various metabolic disorders, diabetes, obesity, etc. The proposed model provides crucial information about the changes in mechanisms of calcium dynamics causing proportionate disturbances in [Formula: see text], ATP and insulin levels in pancreatic cells, which can be helpful for devising protocols for diagnosis and treatment of various metabolic diseases.


Assuntos
Diabetes Mellitus , Doenças Metabólicas , Humanos , Insulina/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Insulina Regular Humana/metabolismo , Cálcio da Dieta
8.
Nutrients ; 16(3)2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38337679

RESUMO

This study aimed to compare newly developed diabetes-specific complete smoothie formulas with a standard diabetes-specific nutritional formula (DSNF) regarding their effects on glucose homeostasis, insulin levels, and lipid metabolism in obese type 2 diabetes (T2DM) patients. We conducted a randomized, double-blind, crossover study with 41 obese T2DM participants to compare two developed diabetes-specific complete smoothie formulas, a soy-based regular smoothie (SM) and a smoothie with modified carbohydrate content (SMMC), with the standard DSNF, Glucerna. Glycemic and insulin responses were assessed after the participants randomly consumed 300 kilocalories of each formulation on three separate days with a 7-day gap between. Postprandial effects on glycemic control, insulin levels, and lipid metabolism were measured. SMMC resulted in a significantly lower glucose area under the curve (AUC0-240) compared to Glucerna and SM (p < 0.05 for both). Insulin AUC0-240 after SMMC was significantly lower than that after SM and Glucerna (p < 0.05). During the diets, the suppression of NEFA was more augmented on SM, resulting in a less total AUC0-240 of NEFA compared to the SMMC diet (p < 0.05). C-peptide AUC0-240 after SMMC was significantly lower than that after Glucerna (p < 0.001). Conversely, glucagon AUC0-240 after SMMC was significantly higher than that after SM and Glucerna (p < 0.05). These results highlight SMMC as the better insulin-sensitive formula, potentially achieved through increased insulin secretion or a direct reduction in glucose absorption. The unique composition of carbohydrates, amino acids, and fats from natural ingredients in the smoothies may contribute to these positive effects, making them promising functional foods for managing diabetes and obesity.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Estudos Cross-Over , Ácidos Graxos não Esterificados , Insulina/metabolismo , Obesidade/complicações , Glucose , Período Pós-Prandial/fisiologia , Glicemia/metabolismo
9.
Int J Mol Sci ; 25(3)2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38339185

RESUMO

Impaired skeletal muscle glucose uptake is a key feature in the development of insulin resistance and type 2 diabetes. Skeletal muscle glucose uptake can be enhanced by a variety of different stimuli, including insulin and contraction as the most prominent. In contrast to the clearance of glucose from the bloodstream in response to insulin stimulation, exercise-induced glucose uptake into skeletal muscle is unaffected during the progression of insulin resistance, placing physical activity at the center of prevention and treatment of metabolic diseases. The two Rab GTPase-activating proteins (RabGAPs), TBC1D1 and TBC1D4, represent critical nodes at the convergence of insulin- and exercise-stimulated signaling pathways, as phosphorylation of the two closely related signaling factors leads to enhanced translocation of glucose transporter 4 (GLUT4) to the plasma membrane, resulting in increased cellular glucose uptake. However, the full network of intracellular signaling pathways that control exercise-induced glucose uptake and that overlap with the insulin-stimulated pathway upstream of the RabGAPs is not fully understood. In this review, we discuss the current state of knowledge on exercise- and insulin-regulated kinases, hypoxia, nitric oxide (NO) and bioactive lipids that may be involved in the regulation of skeletal muscle glucose uptake.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Proteínas Ativadoras de GTPase/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Músculo Esquelético/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Fosforilação , Insulina Regular Humana , Transportador de Glucose Tipo 4/metabolismo , Contração Muscular
10.
BMJ Paediatr Open ; 8(1)2024 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-38341196

RESUMO

OBJECTIVE: To explore the glucose-related hormone profile of very low birthweight (VLBW) infants and assess the association between neonatal hyperglycaemia and insulin resistance during the admission period. DESIGN: A prospective observational study-the Very Low Birth Weight Infants, Glucose and Hormonal Profiles over Time study. SETTING: A tertiary neonatal intensive care unit and four neonatal units in county hospitals in Sweden. PATIENTS: 48 infants born <1500 g (VLBW) during 2016-2019. OUTCOME MEASURES: Plasma concentrations of glucose-related hormones and proteins (C-peptide, insulin, ghrelin, glucagon-like peptide 1 (GLP-1), glucagon, leptin, resistin and proinsulin), insulin:C-peptide and proinsulin:insulin ratios, Homoeostatic Model Assessment 2 (HOMA2) and Quantitative Insulin Sensitivity Check (QUICKI) indices, measured on day of life (DOL) 7 and at postmenstrual age 36 weeks. RESULTS: Lower gestational age was significantly associated with higher glucose, C-peptide, insulin, proinsulin, leptin, ghrelin, resistin and GLP-1 concentrations, increased HOMA2 index, and decreased QUICKI index and proinsulin:insulin ratio. Hyperglycaemic infants had significantly higher glucose, C-peptide, insulin, leptin and proinsulin concentrations, and lower QUICKI index, than normoglycaemic infants. Higher glucose and proinsulin concentrations and insulin:C-peptide ratio, and lower QUICKI index on DOL 7 were significantly associated with longer duration of hyperglycaemia during the admission period. CONCLUSIONS: VLBW infants seem to have a hormone profile consistent with insulin resistance. Lower gestational age and hyperglycaemia are associated with higher concentrations of insulin resistance markers.


Assuntos
Hiperglicemia , Resistência à Insulina , Recém-Nascido , Humanos , Lactente , Proinsulina , Leptina , Grelina , Resistina , Estudos Prospectivos , Peptídeo C , Glicemia/metabolismo , Insulina/metabolismo , Recém-Nascido de muito Baixo Peso , Peptídeo 1 Semelhante ao Glucagon , Hiperglicemia/epidemiologia , Insulina Regular Humana
11.
Iran J Med Sci ; 49(2): 65-76, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38356490

RESUMO

Background: Some studies have evaluated the manipulation of the sonic hedgehog (Shh) signaling pathway to generate more efficient insulin-producing cells (IPCs). In a systematic review, we evaluated in vitro and in vivo studies on the effect of inhibition or activation of the Shh pathway on the production, differentiation, maintenance, and endocrine activity of IPCs. Methods: A systematic review was conducted using all available experimental studies published between January 2000 and November 2022. The review aimed at determining the effect of Shh manipulation on the differentiation of stem cells (SCs) into IPCs. Keywords and phrases using medical subject headings were extracted, and a complete search was performed in Web of Science, Embase, ProQuest, PubMed, Scopus, and Cochrane Library databases. The inclusion criteria were manipulation of Shh in SCs, SCs differentiation into IPCs, and endocrine activity of mature IPCs. Articles with incomplete data and duplications were excluded. Results: A total of 208 articles were initially identified, out of which 11 articles were included in the study. The effect of Shh inhibition in the definitive endoderm stage to produce functional IPCs were confirmed. Some studies showed the importance of Shh re-activation at late-stage differentiation for the generation of efficient IPCs. It is proposed that baseline concentrations of Shh in mature pancreatic ß-cells affect insulin secretion and endocrine activities of the cells. However, Shh overexpression in pancreatic ß-cells ultimately leads to improper endocrine function and inadequate glucose-sensing insulin secretion. Conclusion: Accurate manipulation of the Shh signaling pathway can be an effective approach in the production and maintenance of functional IPCs.


Assuntos
Proteínas Hedgehog , Células Secretoras de Insulina , Proteínas Hedgehog/metabolismo , Proteínas Hedgehog/farmacologia , Insulina/metabolismo , Insulina/farmacologia , Diferenciação Celular/fisiologia , Transdução de Sinais , Células Secretoras de Insulina/metabolismo
12.
Nat Struct Mol Biol ; 31(2): 336-350, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38332366

RESUMO

Phosphatidylinositol 3-kinase α, a heterodimer of catalytic p110α and one of five regulatory subunits, mediates insulin- and insulin like growth factor-signaling and, frequently, oncogenesis. Cellular levels of the regulatory p85α subunit are tightly controlled by regulated proteasomal degradation. In adipose tissue and growth plates, failure of K48-linked p85α ubiquitination causes diabetes, lipodystrophy and dwarfism in mice, as in humans with SHORT syndrome. Here we elucidated the structures of the key ubiquitin ligase complexes regulating p85α availability. Specificity is provided by the substrate receptor KBTBD2, which recruits p85α to the cullin3-RING E3 ubiquitin ligase (CRL3). CRL3KBTBD2 forms multimers, which disassemble into dimers upon substrate binding (CRL3KBTBD2-p85α) and/or neddylation by the activator NEDD8 (CRL3KBTBD2~N8), leading to p85α ubiquitination and degradation. Deactivation involves dissociation of NEDD8 mediated by the COP9 signalosome and displacement of KBTBD2 by the inhibitor CAND1. The hereby identified structural basis of p85α regulation opens the way to better understanding disturbances of glucose regulation, growth and cancer.


Assuntos
Proteínas Culina , Ubiquitina-Proteína Ligases , Humanos , Camundongos , Animais , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Culina/metabolismo , Insulina/metabolismo , Ubiquitinação , Ligação Proteica
13.
J Theor Biol ; 581: 111756, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38307451

RESUMO

The dominant paradigm for modeling the obesity-induced T2DM (type 2 diabetes mellitus) today focuses on glucose and insulin regulatory systems, diabetes pathways, and diagnostic test evaluations. The problem with this approach is that it is not possible to explicitly account for the glucose transport mechanism from the blood to the liver, where the glucose is stored, and from the liver to the blood. This makes it inaccurate, if not incorrect, to properly model the concentration of glucose in the blood in comparison to actual glycated hemoglobin (A1C) test results. In this paper, we develop a mathematical model of glucose dynamics by a system of ODEs. The model includes the mechanism of glucose transport from the blood to the liver, and from the liver to the blood, and explains how obesity is likely to lead to T2DM. We use the model to evaluate the efficacy of an anti-T2DM drug that also reduces weight.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glicemia/metabolismo , Glucose , Insulina/metabolismo , Obesidade/complicações , Obesidade/tratamento farmacológico , Modelos Teóricos
14.
FASEB J ; 38(4): e23490, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38363581

RESUMO

Appropriate Ca2+ concentration in the endoplasmic reticulum (ER), modulating cytosolic Ca2+ signal, serves significant roles in physiological function of pancreatic ß cells. To maintaining ER homeostasis, Ca2+ movement across the ER membrane is always accompanied by a simultaneous K+ flux in the opposite direction. KCNH6 was proven to modulate insulin secretion by controlling plasma membrane action potential duration and intracellular Ca2+ influx. Meanwhile, the specific function of KCNH6 in pancreatic ß-cells remains unclear. In this study, we found that KCNH6 exhibited mainly ER localization and Kcnh6 ß-cell-specific knockout (ßKO) mice suffered from abnormal glucose tolerance and impaired insulin secretion in adulthood. ER Ca2+ store was overloaded in islets of ßKO mice, which contributed to ER stress and ER stress-induced apoptosis in ß cells. Next, we verified that ethanol treatment induced increases in ER Ca2+ store and apoptosis in pancreatic ß cells, whereas adenovirus-mediated KCNH6 overexpression in islets attenuated ethanol-induced ER stress and apoptosis. In addition, tail-vein injections of KCNH6 lentivirus rescued KCNH6 expression in ßKO mice, restored ER Ca2+ overload and attenuated ER stress in ß cells, which further confirms that KCNH6 protects islets from ER stress and apoptosis. These data suggest that KCNH6 on the ER membrane may help to stabilize intracellular ER Ca2+ stores and protect ß cells from ER stress and apoptosis. In conclusion, our study reveals the protective potential of KCNH6-targeting drugs in ER stress-induced diabetes.


Assuntos
Diabetes Mellitus , Células Secretoras de Insulina , Camundongos , Animais , Secreção de Insulina , Diabetes Mellitus/metabolismo , Células Secretoras de Insulina/metabolismo , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Cálcio/metabolismo , Etanol , Insulina/metabolismo
15.
Mol Biol Rep ; 51(1): 354, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38400872

RESUMO

BACKGROUND: Type 2 diabetes is characterized by insulin resistance, which manifests mainly in skeletal muscles. SIRT1 has been found to play a role in the insulin signaling pathway. However, the molecular underpinnings of SIRT1's function in palmitate fatty acid-induced apoptosis still need to be better understood. METHODS: In this research, skeletal muscle cells are treated with palmitate to be insulin resistant. It is approached that SIRT1 is downregulated in C2C12 muscle cells during palmitate-induced apoptosis and that activating SIRT1 mitigates this effect. RESULTS: Based on these findings, palmitate-induced apoptosis suppressed mitochondrial biogenesis by lowering PGC-1 expression, while SIRT1 overexpression boosted. The SIRT1 inhibitor sirtinol, on the other hand, decreased mitochondrial biogenesis under the same conditions. This research also shows that ROS levels rise in the conditions necessary for apoptosis induction by palmitate, and ROS inhibitors can mitigate this effect. This work demonstrated that lowering ROS levels by boosting SIRT1 expression inhibited apoptotic induction in skeletal muscle cells. CONCLUSION: This study's findings suggested that SIRT1 can improve insulin resistance in type 2 diabetes by slowing the rate of lipo-apoptosis and boosting mitochondrial biogenesis, among other benefits.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Palmitatos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Linhagem Celular , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Insulina/metabolismo , Apoptose
16.
Int J Mol Sci ; 25(4)2024 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-38397072

RESUMO

Insulin is a polypeptide hormone synthesized and secreted by pancreatic ß-cells. It plays an important role as a metabolic hormone. Insulin influences the metabolism of glucose, regulating plasma glucose levels and stimulating glucose storage in organs such as the liver, muscles and adipose tissue. It is involved in fat metabolism, increasing the storage of triglycerides and decreasing lipolysis. Ketone body metabolism also depends on insulin action, as insulin reduces ketone body concentrations and influences protein metabolism. It increases nitrogen retention, facilitates the transport of amino acids into cells and increases the synthesis of proteins. Insulin also inhibits protein breakdown and is involved in cellular growth and proliferation. On the other hand, defects in the intracellular signaling pathways of insulin may cause several disturbances in human metabolism, resulting in several chronic diseases. Insulin resistance, also known as impaired insulin sensitivity, is due to the decreased reaction of insulin signaling for glucose levels, seen when glucose use in response to an adequate concentration of insulin is impaired. Insulin resistance may cause, for example, increased plasma insulin levels. That state, called hyperinsulinemia, impairs metabolic processes and is observed in patients with type 2 diabetes mellitus and obesity. Hyperinsulinemia may increase the risk of initiation, progression and metastasis of several cancers and may cause poor cancer outcomes. Insulin resistance is a health problem worldwide; therefore, mechanisms of insulin resistance, causes and types of insulin resistance and strategies against insulin resistance are described in this review. Attention is also paid to factors that are associated with the development of insulin resistance, the main and characteristic symptoms of particular syndromes, plus other aspects of severe insulin resistance. This review mainly focuses on the description and analysis of changes in cells due to insulin resistance.


Assuntos
Diabetes Mellitus Tipo 2 , Hiperinsulinismo , Resistência à Insulina , Humanos , Resistência à Insulina/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Insulina/metabolismo , Glucose/metabolismo , Hiperinsulinismo/complicações , Cetonas
17.
Int J Mol Sci ; 25(4)2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38397122

RESUMO

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its advanced subtype, metabolic dysfunction-associated steatohepatitis (MASH), have emerged as the most common chronic liver disease worldwide, yet there is no targeted pharmacotherapy presently available. This study aimed to investigate the possible in vivo function of STE20-type protein kinase MST4, which was earlier implicated in the regulation of hepatocellular lipotoxic milieu in vitro, in the control of the diet-induced impairment of systemic glucose and insulin homeostasis as well as MASLD susceptibility. Whole-body and liver-specific Mst4 knockout mice were generated by crossbreeding conditional Mst4fl/fl mice with mice expressing Cre recombinase under the Sox2 or Alb promoters, respectively. To replicate the environment in high-risk subjects, Mst4-/- mice and their wild-type littermates were fed a high-fat or a methionine-choline-deficient (MCD) diet. Different in vivo tests were conducted in obese mice to describe the whole-body metabolism. MASLD progression in the liver and lipotoxic damage to adipose tissue, kidney, and skeletal muscle were analyzed by histological and immunofluorescence analysis, biochemical assays, and protein and gene expression profiling. In parallel, intracellular fat storage and oxidative stress were assessed in primary mouse hepatocytes, where MST4 was silenced by small interfering RNA. We found that global MST4 depletion had no effect on body weight or composition, locomotor activity, whole-body glucose tolerance or insulin sensitivity in obese mice. Furthermore, we observed no alterations in lipotoxic injuries to the liver, adipose, kidney, or skeletal muscle tissue in high-fat diet-fed whole-body Mst4-/- vs. wild-type mice. Liver-specific Mst4-/- mice and wild-type littermates displayed a similar severity of MASLD when subjected to an MCD diet, as evidenced by equal levels of steatosis, inflammation, hepatic stellate cell activation, fibrosis, oxidative/ER stress, and apoptosis in the liver. In contrast, the in vitro silencing of MST4 effectively protected primary mouse hepatocytes against ectopic lipid accumulation and oxidative cell injury triggered by exposure to fatty acids. In summary, these results suggest that the genetic ablation of MST4 in mice does not mitigate the initiation or progression of MASLD and has no effect on systemic glucose or insulin homeostasis in the context of nutritional stress. The functional compensation for the genetic loss of MST4 by yet undefined mechanisms may contribute to the apparent discrepancy between in vivo and in vitro phenotypic consequences of MST4 silencing.


Assuntos
Fígado Gorduroso , Doenças Metabólicas , Hepatopatia Gordurosa não Alcoólica , Humanos , Camundongos , Animais , Camundongos Obesos , Hepatócitos/metabolismo , Fígado Gorduroso/metabolismo , Fígado/metabolismo , Glucose/metabolismo , Dieta Hiperlipídica/efeitos adversos , Camundongos Knockout , Colina/metabolismo , Insulina/metabolismo , Doenças Metabólicas/metabolismo , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo
18.
Sci Rep ; 14(1): 3244, 2024 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-38332164

RESUMO

Target identification is a crucial step in elucidating the mechanisms by which functional food components exert their functions. Here, we identified the G-protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5) as a target of the triterpenoid mogrol, a class of aglycone mogroside derivative from Siraitia grosvenorii. Mogrol, but not mogrosides, activated cAMP-response element-mediated transcription in a TGR5-dependent manner. Additionally, mogrol selectively activated TGR5 but not the other bile acid-responsive receptors (i.e., farnesoid X receptor, vitamin D receptor, or muscarinic acetylcholine receptor M3). Several amino acids in TGR5 (L71A2.60, W75AECL1, Q77AECL1, R80AECL1, Y89A3.29, F161AECL2, L166A5.39, Y240A6.51, S247A6.58, Y251A6.62, L262A7.35, and L266A7.39) were found to be important for mogrol-induced activation. Mogrol activated insulin secretion under low-glucose conditions in INS-1 pancreatic ß-cells, which can be inhibited by a TGR5 inhibitor. Similar effects of mogrol on insulin secretion were observed in the isolated mouse islets. Mogrol administration partially but significantly alleviated hyperglycemia in KKAy diabetic mice by increasing the insulin levels without affecting the ß-cell mass or pancreatic insulin content. These results suggest that mogrol stimulates insulin secretion and alleviates hyperglycemia by acting as a TGR5 agonist.


Assuntos
Diabetes Mellitus Experimental , Hiperglicemia , Lanosterol , Fenantrenos , Animais , Camundongos , Ácidos e Sais Biliares , Diabetes Mellitus Experimental/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Hiperglicemia/tratamento farmacológico , Insulina/metabolismo , Secreção de Insulina , Lanosterol/análogos & derivados , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo
19.
Ecotoxicol Environ Saf ; 272: 116056, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38301579

RESUMO

Using Caenorhabditis elegans as animal model, we investigated the effect of exposure to polystyrene nanoparticles (PS-NPs) in the range of µg/L on high glucose toxicity induction. With lifespan and locomotion behavior as endpoints, we observed that PS-NP (10 and 100 µg/L) enhanced toxicity in 50 mM glucose treated animals. In insulin signaling pathway, expressions of genes encoding insulin receptor (daf-2), kinases (age-1 and akt-1/2), and insulin peptides (ins-9, ins-6, and daf-28) were increased, and expressions of daf-16 and its target of sod-3 were decreased in high glucose treated nematodes followed by PS-NP exposure. Toxicity enhancement in high glucose treated nematodes by PS-NP exposure was inhibited by RNAi of daf-2, age-1, akt-2, akt-1, and 3 insulin peptides genes, but increased by RNAi of daf-16 and sod-3. The resistance of animals with RNAi of daf-2 to toxicity in high glucose treated nematodes followed by PS-NP exposure could be suppressed by RNAi of daf-16. Moreover, in high glucose treated animals followed by PS-NP exposure, daf-2 expression was inhibited by RNAi of ins-6, ins-9, and daf-28. Our data demonstrated the risk of PS-NP exposure in enhancing the high glucose toxicity. More importantly, alteration in expression of genes in insulin signaling pathway was associated with the toxicity enhancement in high glucose treated nematodes followed by PS-NP exposure.


Assuntos
Proteínas de Caenorhabditis elegans , Nanopartículas , Animais , Caenorhabditis elegans , Insulina/metabolismo , Poliestirenos/toxicidade , Poliestirenos/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Nanopartículas/toxicidade , Longevidade
20.
Sci Rep ; 14(1): 3158, 2024 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326350

RESUMO

Magnolol is a naturally occurring polyphenolic compound in many edible plants, which has various biological effects including anti-aging and alleviating neurodegenerative diseases. However, the underlying mechanism on longevity is uncertain. In this study, we investigated the effect of magnolol on the lifespan of Caenorhabditis elegans and explored the mechanism. The results showed that magnolol treatment significantly extended the  lifespan of nematode and alleviated senescence-related decline in the nematode model. Meanwhile, magnolol enhanced stress resistance to heat shock, hydrogen peroxide (H2O2), mercuric potassium chloride (MeHgCl) and paraquat (PQ) in nematode. In addition, magnolol reduced reactive oxygen species and malondialdehyde (MDA) levels, and increased superoxide dismutase and catalase (CAT) activities in nematodes. Magnolol also up-regulated gene expression of sod-3, hsp16.2, ctl-3, daf-16, skn-1, hsf-1, sir2.1, etc., down-regulated gene expression of daf-2, and promoted intranuclear translocation of daf-16 in nematodes. The lifespan-extending effect of magnolol were reversed in insulin/IGF signaling (IIS) pathway-related mutant lines, including daf-2, age-1, daf-16, skn-1, hsf-1 and sir-2.1, suggesting that IIS signaling is involved in the modulation of longevity by magnolol. Furthermore, magnolol improved the age-related neurodegeneration in PD and AD C. elegans models. These results indicate that magnolol may enhance lifespan and health span through IIS and sir-2.1 pathways. Thus, the current findings implicate magnolol as a potential candidate to ameliorate the symptoms of aging.


Assuntos
Compostos de Bifenilo , Proteínas de Caenorhabditis elegans , Lignanas , Longevidade , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Peróxido de Hidrogênio/metabolismo , Antioxidantes/metabolismo , Fatores de Transcrição de Choque Térmico/metabolismo , Insulina/metabolismo , Estresse Oxidativo , Fatores de Transcrição Forkhead/metabolismo
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