Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32.423
Filtrar
1.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445431

RESUMO

The insulin receptor (IR) presents two isoforms (IR-A and IR-B) that differ for the α-subunit C-terminal. Both isoforms are expressed in all human cells albeit in different proportions, yet their functional properties-when bound or unbound to insulin-are not well characterized. From a cell model deprived of the Insulin-like Growth Factor 1 Receptor (IGF1-R) we therefore generated cells exhibiting no IR (R-shIR cells), or only human IR-A (R-shIR-A), or exclusively human IR-B (R-shIR-B) and we studied the specific effect of the two isoforms on cell proliferation and cell apoptosis. In the absence of insulin both IR-A and IR-B similarly inhibited proliferation but IR-B was 2-3 fold more effective than IR-A in reducing resistance to etoposide-induced DNA damage. In the presence of insulin, IR-A and IR-B promoted proliferation with the former significantly more effective than the latter at increasing insulin concentrations. Moreover, only insulin-bound IR-A, but not IR-B, protected cells from etoposide-induced cytotoxicity. In conclusion, IR isoforms have different effects on cell proliferation and survival. When unoccupied, IR-A, which is predominantly expressed in undifferentiated and neoplastic cells, is less effective than IR-B in protecting cells from DNA damage. In the presence of insulin, particularly when present at high levels, IR-A provides a selective growth advantage.


Assuntos
Antígenos CD/genética , Resistência a Medicamentos/efeitos dos fármacos , Insulina/farmacologia , RNA Interferente Pequeno/farmacologia , Receptor de Insulina/genética , Animais , Apoptose , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Etoposídeo/farmacologia , Humanos , Camundongos , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Receptor IGF Tipo 1/genética , Receptor de Insulina/antagonistas & inibidores
2.
Int J Nanomedicine ; 16: 4677-4691, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34262275

RESUMO

Background: The clinical use of therapeutic peptides has been limited because of their inefficient delivery approaches and, therefore, inadequate delivery to target sites. Buccal administration of therapeutic peptides offers patients a potential alternative to the current invasive routes of administration. Purpose: The aim of the study was to fabricate hydrophobic ion-pairing (HIP)-nanocomplexes (C1 and C2) utilizing anionic bile salts and cationic peptides, and to assess their permeability across TR146 buccal cell layers and porcine buccal tissue. Methods: C1 and C2-nanocomplexes were fabricated using the HIP approach. In addition, their physiochemical and morphological attributes, in vitro and ex vivo permeability properties, and qualitative and quantitative cellular uptake were evaluated and compared. The localization of C1 and C2-nanocomplexes in porcine buccal tissue was determined using confocal laser scanning microscopy. Results: The C1-nanocomplex was the superior nanocarrier and significantly enhanced the transport of insulin across TR146 cell layers and porcine buccal tissue, exhibiting a 3.00- and 51.76-fold increase in permeability coefficient, respectively, when compared with insulin solution (p < 0.01). C1-nanocomplex was more efficient than C2-nanocomplex at facilitating insulin permeability, with a 2.18- and 27.64-fold increase across TR146 cell layers and porcine buccal tissue, respectively. The C1-nanocomplex demonstrated immense uptake and localization of insulin in TR146 cells and porcine buccal tissue, as evidenced by a highly intense fluorescence in TR146 cells, and a great shift of fluorescence intensity towards the inner region of buccal tissue over time. The increase in fluorescence intensity was observed in the order of C1 > C2 > insulin solution. Conclusion: In this study, we highlighted the efficacy of potential nanocarriers in addressing the daunting issues associated with the invasive administration of insulin and indicated a promising strategy for the buccal administration and delivery of this life-saving peptide hormone.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Insulina/administração & dosagem , Insulina/farmacologia , Mucosa Bucal/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Endocitose/efeitos dos fármacos , Humanos , Íons , Nanopartículas/química , Nanopartículas/ultraestrutura , Suínos
3.
FASEB J ; 35(8): e21828, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34325494

RESUMO

Since prenatal glucocorticoids (GC) excess increases the risk of metabolic dysfunctions in the offspring and its effect on ß-cell recovery capacity remains unknown we investigated these aspects in offspring from mice treated with dexamethasone (DEX) in the late pregnancy. Half of the pups were treated with streptozotocin (STZ) on the sixth postnatal day (PN). Functional and molecular analyses were performed in male offspring on PN25 and PN225. Prenatal DEX treatment resulted in low birth weight. At PN25, both the STZ-treated offspring developed hyperglycemia and had lower ß-cell mass, in parallel with higher α-cell mass and glucose intolerance, with no impact of prenatal DEX on such parameters. At PN225, the ß-cell mass was partially recovered in the STZ-treated mice, but they remained glucose-intolerant, irrespective of being insulin sensitive. Prenatal exposition to DEX predisposed adult offspring to sustained hyperglycemia and perturbed islet function (lower insulin and higher glucagon response to glucose) in parallel with exacerbated glucose intolerance. ß-cell-specific knockdown of the Hnf4α in mice from the DS group resulted in exacerbated glucose intolerance. We conclude that high GC exposure during the prenatal period exacerbates the metabolic dysfunctions in adult life of mice exposed to STZ early in life, resulting in a lesser ability to recover the islets' function over time. This study alerts to the importance of proper management of exogenous GCs during pregnancy and a healthy postnatal lifestyle since the combination of adverse factors during the prenatal and postnatal period accentuates the predisposition to metabolic disorders in adult life.


Assuntos
Dexametasona/toxicidade , Glucocorticoides/toxicidade , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/fisiologia , Animais , Animais Geneticamente Modificados , Animais Recém-Nascidos , Dexametasona/administração & dosagem , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Glucocorticoides/administração & dosagem , Teste de Tolerância a Glucose , Insulina/farmacologia , Camundongos , Neoplasias Experimentais , Gravidez , Efeitos Tardios da Exposição Pré-Natal , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
4.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203120

RESUMO

Activated alpha-2 Macroglobulin (α2M*) is specifically recognized by the cluster I/II of LRP1 (Low-density lipoprotein Receptor-related Protein-1). LRP1 is a scaffold protein for insulin receptor involved in the insulin-induced glucose transporter type 4 (GLUT4) translocation to plasma membrane and glucose uptake in different types of cells. Moreover, the cluster II of LRP1 plays a critical role in the internalization of atherogenic lipoproteins, such as aggregated Low-density Lipoproteins (aggLDL), promoting intracellular cholesteryl ester (CE) accumulation mainly in arterial intima and myocardium. The aggLDL uptake by LRP1 impairs GLUT4 traffic and the insulin response in cardiomyocytes. However, the link between CE accumulation, insulin action, and cardiac dysfunction are largely unknown. Here, we found that α2M* increased GLUT4 expression on cell surface by Rab4, Rab8A, and Rab10-mediated recycling through PI3K/Akt and MAPK/ERK signaling activation. Moreover, α2M* enhanced the insulin response increasing insulin-induced glucose uptake rate in the myocardium under normal conditions. On the other hand, α2M* blocked the intracellular CE accumulation, improved the insulin response and reduced cardiac damage in HL-1 cardiomyocytes exposed to aggLDL. In conclusion, α2M* by its agonist action on LRP1, counteracts the deleterious effects of aggLDL in cardiomyocytes, which may have therapeutic implications in cardiovascular diseases associated with hypercholesterolemia.


Assuntos
Membrana Celular/metabolismo , Insulina/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Macroglobulinas/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Western Blotting , Linhagem Celular , Glucose/metabolismo , Insulina/farmacologia , Lipoproteínas LDL/genética , Lipoproteínas LDL/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Camundongos , Microscopia Confocal , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/fisiologia
5.
Int J Mol Sci ; 22(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203166

RESUMO

Placental dysfunction can lead to fetal growth restriction which is associated with perinatal morbidity and mortality. Fetal growth restriction increases the risk of obesity and diabetes later in life. Placental O-GlcNAc transferase (OGT) has been identified as a marker and a mediator of placental insufficiency in the setting of prenatal stress, however, its role in the fetal programming of metabolism and glucose homeostasis remains unknown. We aim to determine the long-term metabolic outcomes of offspring with a reduction in placental OGT. Mice with a partial reduction and a full knockout of placenta-specific OGT were generated utilizing the Cre-Lox system. Glucose homeostasis and metabolic parameters were assessed on a normal chow and a high-fat diet in both male and female adult offspring. A reduction in placental OGT did not demonstrate differences in the metabolic parameters or glucose homeostasis compared to the controls on a standard chow. The high-fat diet provided a metabolic challenge that revealed a decrease in body weight gain (p = 0.02) and an improved insulin tolerance (p = 0.03) for offspring with a partially reduced placental OGT but not when OGT was fully knocked out. Changes in body weight were not associated with changes in energy homeostasis. Offspring with a partial reduction in placental OGT demonstrated increased hepatic Akt phosphorylation in response to insulin treatment (p = 0.02). A partial reduction in placental OGT was protective from weight gain and insulin intolerance when faced with the metabolic challenge of a high-fat diet. This appears to be, in part, due to increased hepatic insulin signaling. The findings of this study contribute to the greater understanding of fetal metabolic programming and the effect of placental OGT on peripheral insulin sensitivity and provides a target for future investigation and clinical applications.


Assuntos
Acetilglucosamina/metabolismo , Peso Corporal/fisiologia , Resistência à Insulina/fisiologia , Insulina/farmacologia , N-Acetilglucosaminiltransferases/metabolismo , Placenta/efeitos dos fármacos , Placenta/metabolismo , Animais , Peso Corporal/genética , Feminino , Resistência à Insulina/genética , Masculino , Camundongos , N-Acetilglucosaminiltransferases/genética , Gravidez
6.
Comput Biol Med ; 135: 104640, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34261004

RESUMO

Cisplatin is a DNA-damaging chemotherapeutic agent used for treating cancer. Based on cDNA dataset analysis, we investigated how cisplatin modified gene expression and observed cisplatin-induced dysregulation and system-level variations relating to insulin resistance and type 2 diabetes mellitus (T2DM). T2DM is a multifactorial disease affecting 462 million people in the world, and drug-induced T2DM is a serious issue. To understand this etiology, we designed an integrative, system-level study to identify associations between cisplatin-induced differentially expressed genes (DEGs) and T2DM. From a list of differential expressed genes, cisplatin downregulated the cyclin-dependent kinase inhibitor 1 (CDKN1A), tumor necrosis factor (FAS), and sestrin-1 (SESN1) genes responsible for modifying signaling pathways, including the p53, JAK-STAT, FOXO, MAPK, mTOR, P13-AKT, Toll-like receptor (TLR), adipocytokine, and insulin signaling pathways. These enriched pathways were expressively associated with the disease. We observed significant gene signatures, including SMAD3, IRS, PDK1, PRKAA1, AKT, SOS, RAS, GRB2, MEK1/2, and ERK, interacting with source genes. This study revealed the value of system genetics for identifying the cisplatin-induced genetic variants responsible for the progression of T2DM. Also, by cross-validating gene expression data for T2DM islets, we found that downregulating IRS and PRK families is critical in insulin and T2DM signaling pathways. Cisplatin, by inhibiting CDKN1A, FAS, and SESN1, promotes IRS and PRK activity in a similar way to rosiglitazone (a popular drug used for T2DM treatment). Our integrative, network-based approach can help in understanding the drug-induced pathophysiological mechanisms of diabetes.


Assuntos
Antineoplásicos , Diabetes Mellitus Tipo 2 , Antineoplásicos/farmacologia , Cisplatino/farmacologia , Inibidor de Quinase Dependente de Ciclina p21/farmacologia , Inibidor de Quinase Dependente de Ciclina p21/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/genética , Proteínas de Choque Térmico/farmacologia , Proteínas de Choque Térmico/uso terapêutico , Humanos , Insulina/farmacologia , Transdução de Sinais
7.
Molecules ; 26(14)2021 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-34299620

RESUMO

Type 2 diabetes mellitus (T2DM) is linked to insulin resistance and a loss of insulin sensitivity, leading to millions of deaths worldwide each year. T2DM is caused by reduced uptake of glucose facilitated by glucose transporter 4 (GLUT4) in muscle and adipose tissue due to decreased intracellular translocation of GLUT4-containing vesicles to the plasma membrane. To treat T2DM, novel medications are required. Through a fluorescence microscopy-based high-content screen, we tested more than 600 plant extracts for their potential to induce GLUT4 translocation in the absence of insulin. The primary screen in CHO-K1 cells resulted in 30 positive hits, which were further investigated in HeLa and 3T3-L1 cells. In addition, full plasma membrane insertion was examined by immunostaining of the first extracellular loop of GLUT4. The application of appropriate inhibitors identified PI3 kinase as the most important signal transduction target relevant for GLUT4 translocation. Finally, from the most effective hits in vitro, four extracts effectively reduced blood glucose levels in chicken embryos (in ovo), indicating their applicability as antidiabetic pharmaceuticals or nutraceuticals.


Assuntos
Glicemia/efeitos dos fármacos , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Extratos Vegetais/farmacologia , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Células CHO , Linhagem Celular , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cricetulus , Diabetes Mellitus Tipo 2 , Transportador de Glucose Tipo 4/metabolismo , Células HeLa , Humanos , Resistência à Insulina/fisiologia , Camundongos , Transporte Proteico/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
8.
Nutrients ; 13(6)2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34200105

RESUMO

Consumption of prebiotic inulin has been found to increase calcium absorption, which may protect against gut diseases such as colorectal cancer. This dietary relation may be modulated by compositional changes in the gut microbiota; however, no human study has addressed this hypothesis. We determined the feasibility of a randomized crossover trial to evaluate the effect of three interventions (combined calcium and inulin supplementation, calcium supplementation alone, and inulin supplementation alone) on the intestinal microbiota composition and function. We conducted a 16-week pilot study in 12 healthy adults who consumed the three interventions in a random sequence. Participants provided fecal and blood samples before and after each intervention. Each intervention period lasted four weeks and was flanked by one-week washout periods. 16S ribosomal RNA sequencing and quantification of short chain fatty acids (SCFA) was determined in fecal samples. Systemic lipopolysaccharide binding protein (LBP) was quantified in serum. Of the 12 individuals assigned to an intervention sequence, seven completed the study. Reasons for dropout included time (n = 3), gastrointestinal discomfort (n = 1), and moving (n = 1). Overall, participants reported positive attitudes towards the protocol (n = 9) but were unsatisfied by the practicalities of supplement consumption (44%) and experienced digestive discomfort (56%). We found no appreciable differences in microbial composition, SCFA concentration, nor LBP concentrations when comparing intervention periods. In conclusion, an intervention study using a randomized crossover design with calcium and a prebiotic fiber is feasible. Improvements of our study design include using a lower dose prebiotic fiber supplement and a larger sample size.


Assuntos
Cálcio na Dieta/farmacologia , Fibras na Dieta/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Proteínas de Fase Aguda , Adolescente , Adulto , Cálcio na Dieta/administração & dosagem , Proteínas de Transporte/sangue , Estudos Cross-Over , Fibras na Dieta/administração & dosagem , Suplementos Nutricionais , Quimioterapia Combinada , Ácidos Graxos Voláteis/análise , Estudos de Viabilidade , Fezes/química , Feminino , Microbioma Gastrointestinal/genética , Haptoglobinas , Humanos , Insulina/administração & dosagem , Insulina/farmacologia , Masculino , Glicoproteínas de Membrana/sangue , Prebióticos , Precursores de Proteínas/sangue , RNA Ribossômico 16S/genética , Inquéritos e Questionários , Adulto Jovem
9.
Nat Commun ; 12(1): 4386, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34282152

RESUMO

Acute pancreatitis (AP) is serious inflammatory disease of the pancreas. Accumulating evidence links diabetes with severity of AP, suggesting that endogenous insulin may be protective. We investigated this putative protective effect of insulin during cellular and in vivo models of AP in diabetic mice (Ins2Akita) and Pancreatic Acinar cell-specific Conditional Insulin Receptor Knock Out mice (PACIRKO). Caerulein and palmitoleic acid (POA)/ethanol-induced pancreatitis was more severe in both Ins2Akita and PACIRKO vs control mice, suggesting that endogenous insulin directly protects acinar cells in vivo. In isolated pancreatic acinar cells, insulin induced Akt-mediated phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2 (PFKFB2) which upregulated glycolysis thereby preventing POA-induced ATP depletion, inhibition of the ATP-dependent plasma membrane Ca2+ ATPase (PMCA) and cytotoxic Ca2+ overload. These data provide the first mechanistic link between diabetes and severity of AP and suggest that phosphorylation of PFKFB2 may represent a potential therapeutic strategy for treatment of AP.


Assuntos
Células Acinares/metabolismo , Trifosfato de Adenosina/metabolismo , Cálcio/metabolismo , Glicólise/efeitos dos fármacos , Insulina/metabolismo , Insulina/farmacologia , Pancreatite/metabolismo , Substâncias Protetoras/farmacologia , Células Acinares/efeitos dos fármacos , Doença Aguda , Animais , ATPases Transportadoras de Cálcio/metabolismo , Ceruletídeo , Diabetes Mellitus Experimental/metabolismo , Ácidos Graxos Monoinsaturados , Masculino , Camundongos , Camundongos Knockout , Pâncreas/metabolismo , Pancreatite/tratamento farmacológico , Pancreatite/patologia
10.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201755

RESUMO

Diabetes mellitus is a debilitating disease, plaguing a significant number of people around the globe. Attempts to develop new drugs on well-defined atoxic metalloforms, which are capable of influencing fundamental cellular processes overcoming insulin resistance, has triggered an upsurge in molecular research linked to zinc metallodrugs. To that end, meticulous efforts were launched toward the design and synthesis of materials with insulin mimetic potential. Henceforth, trigonelline and N-(2-hydroxyethyl)-iminodiacetic acid (HEIDAH2) were selected as organic substrates seeking binding to zinc (Zn(II)), with new crystalline compounds characterized by elemental analysis, FT-IR, X-rays, thermogravimetry (TGA), luminescence, NMR, and ESI-MS spectrometry. Physicochemical characterization was followed by in vitro biochemical experiments, in which three out of the five zinc compounds emerged as atoxic, exhibiting bio-activity profiles reflecting enhanced adipogenic potential. Concurrently, well-defined qualitative-quantitative experiments provided links to genetic loci responsible for the observed effects, thereby unraveling their key involvement in signaling pathways in adipocyte tissue and insulin mimetic behavior. The collective results (a) signify the quintessential role of molecular studies in unearthing unknown facets of pathophysiological events in diabetes mellitus II, (b) reflect the close associations of properly configured molecular zincoforms to well-defined biological profiles, and (c) set the stage for further physicochemical-based development of efficient zinc antidiabetic metallodrugs.


Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia , Insulina/farmacologia , Compostos Organometálicos/farmacocinética , Zinco/química , Células 3T3-L1 , Animais , Hipoglicemiantes/farmacologia , Camundongos , Transdução de Sinais
11.
J Biol Regul Homeost Agents ; 35(3): 1029-1040, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34155876

RESUMO

Proliferation of vascular smooth muscle cells (VSMCs) participates in multiple cardiovascular disorders, while the mechanism remains unclear. This study aims to investigate the effects of insulin on VSMC. Insulin was used to stimulate rat VSMCs, and the effects on cell cycle and proliferation were subsequently analyzed using flow cytometry. Furthermore, AP-1 and SM-α overexpression vectors were constructed and transfected into VSMCs. AP-1 and SM-α were inhibited by SR11302 and SM-α siRNA, respectively. The mRNA and protein expression levels were subsequently detected using the reversetranscription quantitative polymerase chain reaction and western blotting, respectively. AP-1 and SM-α gene promoter binding sites were determined using luciferase and chromatin immunoprecipitation assays. As a result, we found that high dose of insulin promoted proliferation of VSMCs and increased the percentage of cells in the S phase by downregulating AP-1. AP-1 was identified to bind to the SM-α gene promoter at locus 2-177 to upregulate SM-α gene expression. Inhibition of AP-1 led to the decrease of SM-α expression. Overexpression of SM-α directly suppressed proliferation of VSMCs, while knocking it down promoted the process. Therefore, this study revealed that insulin downregulated the expression of the SM-α gene by inhibiting AP-1, which in turn facilitated proliferation of VSMCs.


Assuntos
Músculo Liso Vascular , Fator de Transcrição AP-1 , Actinas , Animais , Proliferação de Células , Células Cultivadas , Insulina/farmacologia , Miócitos de Músculo Liso , Ratos , Fator de Transcrição AP-1/genética
12.
Nat Commun ; 12(1): 3838, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-34158480

RESUMO

Chronic dietary protein-restriction can create essential amino acid deficiencies and induce metabolic adaptation through the hepatic FGF21 pathway which serves to maintain host fitness during prolonged states of nutritional imbalance. Similarly, the gut microbiome undergoes metabolic adaptations when dietary nutrients are added or withdrawn. Here we confirm previous reports that dietary protein-restriction triggers the hepatic FGF21 adaptive metabolic pathway and further demonstrate that this response is mediated by the gut microbiome and can be tuned through dietary supplementation of fibers that alter the gut microbiome. In the absence of a gut microbiome, we discover that FGF21 is de-sensitized to the effect of protein-restriction. These data suggest that host-intrinsic adaptive pathways to chronic dietary protein-restriction, such as the hepatic FGF21 pathway, may in-fact be responding first to adaptive metabolic changes in the gut microbiome.


Assuntos
Adaptação Fisiológica/fisiologia , Dieta com Restrição de Proteínas , Proteínas na Dieta/administração & dosagem , Fatores de Crescimento de Fibroblastos/metabolismo , Microbioma Gastrointestinal/fisiologia , Estresse Fisiológico/fisiologia , Animais , Bactérias/classificação , Bactérias/genética , Celulose/administração & dosagem , Celulose/farmacologia , Proteínas na Dieta/metabolismo , Microbioma Gastrointestinal/efeitos dos fármacos , Insulina/administração & dosagem , Insulina/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Dinâmica Populacional , RNA Ribossômico 16S/genética , Fatores de Tempo
13.
FASEB J ; 35(7): e21728, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34110658

RESUMO

Proliferation and differentiation of preadipocytes, and other cell types, is accompanied by an increase in glucose uptake. Previous work showed that a pulse of high glucose was required during the first 3 days of differentiation in vitro, but was not required after that. The specific glucose metabolism pathways required for adipocyte differentiation are unknown. Herein, we used 3T3-L1 adipocytes as a model system to study glucose metabolism and expansion of the adipocyte metabolome during the first 3 days of differentiation. Our primary outcome measures were GLUT4 and adiponectin, key proteins associated with healthy adipocytes. Using complete media with 0 or 5 mM glucose, we distinguished between developmental features that were dependent on the differentiation cocktail of dexamethasone, insulin, and isobutylmethylxanthine alone or the cocktail plus glucose. Cocktail alone was sufficient to activate the capacity for 2-deoxglucose uptake and glycolysis, but was unable to support the expression of GLUT4 and adiponectin in mature adipocytes. In contrast, 5 mM glucose in the media promoted a transient increase in glucose uptake and glycolysis as well as a significant expansion of the adipocyte metabolome and proteome. Using genetic and pharmacologic approaches, we found that the positive effects of 5 mM glucose on adipocyte differentiation were specifically due to increased expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a key regulator of glycolysis and the ancillary glucose metabolic pathways. Our data reveal a critical role for PFKFB3 activity in regulating the cellular metabolic remodeling required for adipocyte differentiation and maturation.


Assuntos
Adipócitos/metabolismo , Glucose/metabolismo , Fosfofrutoquinase-2/metabolismo , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adiponectina/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Linhagem Celular , Dexametasona/farmacologia , Transportador de Glucose Tipo 4/metabolismo , Glicólise/efeitos dos fármacos , Glicólise/fisiologia , Insulina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Xantinas/farmacologia
14.
Toxicol Lett ; 349: 40-50, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34118311

RESUMO

Previously, we reported that prolonged arsenic exposure impaired neuronal insulin signaling. Here we have further identified novel molecular mechanisms underlying neuronal insulin signaling impairment by arsenic. Arsenic treatment altered insulin dose-response curve and reduced maximum insulin response in differentiated human neuroblastoma SH-SY5Y cells, suggesting that arsenic hindered neuronal insulin signaling in a non-competitive like manner. Mechanistically, arsenic suppressed insulin receptor (IR) kinase activity, as witnessed by a decreased insulin-activated autophosphorylation of IR at Y1150/1151. Arsenic decreased the level of insulin receptor substrate 1 (IRS1) but increased the protein ratio between PI3K regulatory subunit, p85, and PI3K catalytic subunit, p110. Interestingly, co-immunoprecipitation demonstrated that arsenic did not alter a level of PI3K-p110/PI3K-p85 complex while increased PI3K-p85 levels in a PI3K-p110 depletion supernatant resulted from PI3K-p110 immunoprecipitation. These results indicated that arsenic increased PI3K-p85 which was free from PI3K-p110 binding. In addition, arsenic significantly increased interaction between IRS1 and PI3K-p85 but not PI3K-p110, suggesting that there may be a fraction of free PI3K-p85 interacting with IRS1. In vitro PI3K activity demonstrated that arsenic lowered PI3K activity in both basal and insulin-stimulated conditions. These results suggested that the increase in free PI3K-p85 by arsenic might compete with PI3K heterodimer for the same IRS1 binding site, in turn blocking the activation of its catalytic subunit, PI3K-p110. Taken together, our results provide additional insights into mechanisms underlying the impairment of neuronal insulin signaling by arsenic through the reduction of IR autophosphorylation, the increase in free PI3K-p85, and the impeding of PI3K activity.


Assuntos
Arsenitos/toxicidade , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Insulina/farmacologia , Neurônios/efeitos dos fármacos , Compostos de Sódio/toxicidade , Antígenos CD/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Neurônios/enzimologia , Neurônios/patologia , Fosforilação , Ligação Proteica , Receptor de Insulina/agonistas , Receptor de Insulina/metabolismo , Transdução de Sinais
15.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072724

RESUMO

At the onset of lactation, dairy cows suffer from insulin resistance, insulin deficiency or both, similar to human diabetes, resulting in lipolysis, ketosis and fatty liver. This work explored the combined effects of different levels of magnesium (0.1, 0.3, 1 and 3 mM) and insulin (25, 250 and 25,000 pM) on metabolic pathways and the expression of magnesium-responsive genes in a bovine adipocyte model. Magnesium starvation (0.1 mM) and low insulin (25 pM) independently decreased or tended to decrease the accumulation of non-polar lipids and uptake of the glucose analog 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-6-deoxyglucose (6-NBDG). Activity of glycerol 3-phosphate dehydrogenase (GPDH) was highest at 25 pM insulin and 3 mM magnesium. Expression of SLC41A1 and SLC41A3 was reduced at 0.1 mM magnesium either across insulin concentrations (SLC41A1) or at 250 pM insulin (SLC41A3). MAGT1 expression was reduced at 3 mM magnesium. NIPA1 expression was reduced at 3 mM and 0.1 mM magnesium at 25 and 250 pM insulin, respectively. Expression of SLC41A2, CNNM2, TRPM6 and TRPM7 was not affected. We conclude that magnesium promotes lipogenesis in adipocytes and inversely regulates the transcription of genes that increase vs. decrease cytosolic magnesium concentration. The induction of GAPDH activity by surplus magnesium at low insulin concentration can counteract excessive lipomobilization.


Assuntos
Adipócitos/metabolismo , Metabolismo Energético , Regulação da Expressão Gênica , Homeostase , Insulina/metabolismo , Magnésio/metabolismo , Adipócitos/efeitos dos fármacos , Animais , Bovinos , Células Cultivadas , Metabolismo Energético/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Insulina/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Magnésio/farmacologia , Álcool Oxidorredutases Dependentes de NAD(+) e NADP(+)/metabolismo
16.
Int J Mol Sci ; 22(11)2021 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-34071138

RESUMO

Schwann cells play an important role in peripheral nerve function, and their dysfunction has been implicated in the pathogenesis of diabetic neuropathy and other demyelinating diseases. The physiological functions of insulin in Schwann cells remain unclear and therefore define the aim of this study. By using immortalized adult Fischer rat Schwann cells (IFRS1), we investigated the mechanism of the stimulating effects of insulin on the cell proliferation and expression of myelin proteins (myelin protein zero (MPZ) and myelin basic protein (MBP). The application of insulin to IFRS1 cells increased the proliferative activity and induced phosphorylation of Akt and ERK, but not P38-MAPK. The proliferative potential of insulin-stimulated IFRS1 was significantly suppressed by the addition of LY294002, a PI3 kinase inhibitor. The insulin-stimulated increase in MPZ expression was significantly suppressed by the addition of PD98059, a MEK inhibitor. Furthermore, insulin-increased MBP expression was significantly suppressed by the addition of LY294002. These findings suggest that both PI3-K/Akt and ERK/MEK pathways are involved in insulin-induced cell growth and upregulation of MPZ and MBP in IFRS1 Schwann cells.


Assuntos
Insulina/farmacologia , Células de Schwann/efeitos dos fármacos , Animais , Divisão Celular/efeitos dos fármacos , Linhagem Celular Transformada , Cromonas/farmacologia , Neuropatias Diabéticas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Flavonoides/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Morfolinas/farmacologia , Proteínas da Mielina/biossíntese , Proteínas da Mielina/genética , Fosfatidilinositol 3-Quinases/efeitos dos fármacos , Fosforilação , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Endogâmicos F344 , Receptor de Insulina/biossíntese , Receptor de Insulina/genética , Transdução de Sinais/efeitos dos fármacos
17.
Diabetes ; 70(8): 1826-1842, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33980689

RESUMO

Ethnic groups are physiologically and genetically adapted to their diets. Inuit bear a frequent AS160R684X mutation that causes type 2 diabetes. Whether this mutation evolutionarily confers adaptation in Inuit and how it causes metabolic disorders upon dietary changes are unknown due to limitations in human studies. Here, we develop a genetically modified rat model bearing an orthologous AS160R693X mutation, which mimics human patients exhibiting postprandial hyperglycemia and hyperinsulinemia. Importantly, a sugar-rich diet aggravates metabolic abnormalities in AS160R693X rats. The AS160R693X mutation diminishes a dominant long-variant AS160 without affecting a minor short-variant AS160 in skeletal muscle, which suppresses muscle glucose utilization but induces fatty acid oxidation. This fuel switch suggests a possible adaptation in Inuit who traditionally had lipid-rich hypoglycemic diets. Finally, induction of the short-variant AS160 restores glucose utilization in rat myocytes and a mouse model. Our findings have implications for development of precision treatments for patients bearing the AS160R684X mutation.


Assuntos
Alelos , Ácidos Graxos/metabolismo , Proteínas Ativadoras de GTPase/genética , Músculo Esquelético/metabolismo , Mutação , Animais , Proteínas Ativadoras de GTPase/metabolismo , Insulina/farmacologia , Camundongos , Músculo Esquelético/efeitos dos fármacos , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Ratos
18.
Diabetes ; 70(8): 1857-1873, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34031123

RESUMO

The brain is now recognized as an insulin-sensitive tissue; however, the role of changing insulin concentrations in the peripheral circulation in gene expression in the brain is largely unknown. Here, we performed a hyperinsulinemic-euglycemic clamp on 3-month-old male C57BL/6 mice for 3 h. We show that, in comparison with results in saline-infused controls, increases in peripheral insulin within the physiological range regulate expression of a broad network of genes in the brain. Insulin regulates distinct pathways in the hypothalamus (HTM), hippocampus, and nucleus accumbens. Insulin shows its most robust effect in the HTM and regulates multiple genes involved in neurotransmission, including upregulating expression of multiple subunits of GABA-A receptors, Na+ and K+ channels, and SNARE proteins; differentially modulating glutamate receptors; and suppressing multiple neuropeptides. Insulin also strongly modulates metabolic genes in the HTM, suppressing genes in the glycolysis and pentose phosphate pathways, while increasing expression of genes regulating pyruvate dehydrogenase and long-chain fatty acyl-CoA and cholesterol biosynthesis, thereby rerouting of carbon substrates from glucose metabolism to lipid metabolism required for the biogenesis of membranes for neuronal and glial function and synaptic remodeling. Furthermore, based on the transcriptional signatures, these changes in gene expression involve neurons, astrocytes, oligodendrocytes, microglia, and endothelial cells. Thus, peripheral insulin acutely and potently regulates expression of a broad network of genes involved in neurotransmission and brain metabolism. Dysregulation of these pathways could have dramatic effects in normal physiology and diabetes.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Hipotálamo/metabolismo , Insulina/farmacologia , Lipogênese/fisiologia , Núcleo Accumbens/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Técnica Clamp de Glucose , Hipocampo/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Lipogênese/efeitos dos fármacos , Masculino , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleo Accumbens/efeitos dos fármacos
19.
Am J Physiol Endocrinol Metab ; 321(1): E156-E163, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34056920

RESUMO

The brain has been traditionally thought to be insensitive to insulin, primarily because insulin does not stimulate glucose uptake/metabolism in the brain (as it does in classic insulin-sensitive tissues such as muscle, liver, and fat). However, over the past 20 years, research in this field has identified unique actions of insulin in the brain. There is accumulating evidence that insulin crosses into the brain and regulates central nervous system functions such as feeding, depression, and cognitive behavior. In addition, insulin acts in the brain to regulate systemic functions such as hepatic glucose production, lipolysis, lipogenesis, reproductive competence, and the sympathoadrenal response to hypoglycemia. Decrements in brain insulin action (or brain insulin resistance) can be observed in obesity, type 2 diabetes (T2DM), aging, and Alzheimer's disease (AD), indicating a possible link between metabolic and cognitive health. Here, we describe recent findings on the pleiotropic actions of insulin in the brain and highlight the precise sites, specific neuronal population, and roles for supportive astrocytic cells through which insulin acts in the brain. In addition, we also discuss how boosting brain insulin action could be a therapeutic option for people at an increased risk of developing metabolic and cognitive diseases such as AD and T2DM. Overall, this perspective article serves to highlight some of these key scientific findings, identify unresolved issues, and indicate future directions of research in this field that would serve to improve the lives of people with metabolic and cognitive dysfunctions.


Assuntos
Encéfalo/fisiologia , Insulina/fisiologia , Doença de Alzheimer , Ansiedade , Barreira Hematoencefálica/metabolismo , Peso Corporal , Encéfalo/efeitos dos fármacos , Colesterol/biossíntese , Cognição , Depressão , Ingestão de Alimentos , Glucose/biossíntese , Humanos , Insulina/metabolismo , Insulina/farmacologia , Metabolismo dos Lipídeos/fisiologia
20.
J Med Chem ; 64(13): 8942-8950, 2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-33944562

RESUMO

Here, we describe the molecular engineering of insulin icodec to achieve a plasma half-life of 196 h in humans, suitable for once-weekly subcutaneously administration. Insulin icodec is based on re-engineering of the ultra-long oral basal insulin OI338 with a plasma half-life of 70 h in humans. This systematic re-engineering was accomplished by (1) further increasing the albumin binding by changing the fatty diacid from a 1,18-octadecanedioic acid (C18) to a 1,20-icosanedioic acid (C20) and (2) further reducing the insulin receptor affinity by the B16Tyr → His substitution. Insulin icodec was selected by screening for long intravenous plasma half-life in dogs while ensuring glucose-lowering potency following subcutaneous administration in rats. The ensuing structure-activity relationship resulted in insulin icodec. In phase-2 clinical trial, once-weekly insulin icodec provided safe and efficacious glycemic control comparable to once-daily insulin glargine in type 2 diabetes patients. The structure-activity relationship study leading to insulin icodec is presented here.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Animais , Cães , Esquema de Medicação , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Injeções Intravenosas , Injeções Subcutâneas , Insulina/administração & dosagem , Insulina/análogos & derivados , Masculino , Ratos , Ratos Sprague-Dawley
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...