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1.
Curr Top Med Chem ; 19(16): 1436-1444, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31512997

RESUMO

Type 2 diabetes is a major health issue worldwide with complex metabolic and endocrine abnormalities. Hyperglycemia, defects in insulin secretion and insulin resistance are classic features of type 2 diabetes. Insulin signaling regulates metabolic homeostasis by regulating glucose and lipid turnover in the liver, skeletal muscle and adipose tissue. Major treatment modalities for diabetes include the drugs from the class of sulfonyl urea, Insulin, GLP-1 agonists, SGLT2 inhibitors, DPP-IV inhibitors and Thiazolidinediones. Emerging antidiabetic therapeutics also include classes of drugs targeting GPCRs in the liver, adipose tissue and skeletal muscle. Interestingly, recent research highlights several shared intermediates between insulin and GPCR signaling cascades opening potential novel avenues for diabetic drug discovery.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Descoberta de Drogas , Hipoglicemiantes/farmacologia , Receptor de Insulina/antagonistas & inibidores , Receptores Acoplados a Proteínas-G/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Animais , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Hipoglicemiantes/química , Receptor de Insulina/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo
2.
Expert Opin Ther Pat ; 29(9): 689-702, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31402706

RESUMO

Introduction: Protein tyrosine phosphatase 1B (PTP1B) inhibition has been recommended as a crucial strategy to enhance insulin sensitivity in various cells and this fact is supported by human genetic data. PTP1B inhibitors improve the sensitivity of the insulin receptor and have the ability to cure insulin resistance-related diseases. In the latter years, targeting PTP1B inhibitors is being considered an attractive target to treat T2DM and therefore libraries of PTP1B inhibitors are being suggested as potent antidiabetic drugs. Areas covered: This review provides an overview of published patents from January 2015 to December 2018. The review describes the effectiveness of potent PTP1B inhibitors as pharmaceutical agents to treat type 2 diabetes. Expert opinion: Enormous developments have been made in PTP1B drug discovery which describes progress in natural products, synthetic heterocyclic scaffolds or heterocyclic hybrid compounds. Various protocols are being followed to boost the pharmacological effects of PTP1B inhibitors. Moreover these new advancements suggest that it is possible to get small-molecule PTP1B inhibitors with the required potency and selectivity. Furthermore, future endevours via an integrated strategy of using medicinal chemistry and structural biology will hopefully result in potent and selective PTP1B inhibitors as well as safer and more effective orally available drugs.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Antígenos CD/metabolismo , Diabetes Mellitus Tipo 2/enzimologia , Desenho de Drogas , Descoberta de Drogas/métodos , Inibidores Enzimáticos/farmacologia , Humanos , Patentes como Assunto , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Receptor de Insulina/metabolismo
3.
J Agric Food Chem ; 67(34): 9510-9521, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31382738

RESUMO

Glutamate (Glu) is a critical nutritional regulator of intestinal epithelial homeostasis. In addition, intestinal stem cells (ISCs) at crypt bases are known to play important roles in maintaining the renewal and homeostasis of the intestinal epithelium, and the aspects of communication between Glu and ISCs are still unknown. Here, we identify Glu and mammalian target of rapamycin complex 1 (mTORC1) as essential regulators of ISC expansion. The results showed that extracellular Glu promoted ISC expansion, indicated by increased intestinal organoid forming efficiency and budding efficiency as well as cell proliferation marker Ki67 immunofluorescence and differentiation marker Keratin 20 (KRT20) expression. Moreover, the insulin receptor (IR) mediating phosphorylation of the insulin receptor substrate (IRS) and downstream signaling phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway was involved in this response in ISCs. As expected, Glu-induced mTORC1 signaling activation was observed in the intestinal porcine enterocyte cell line (IPEC-J2), and Glu activated the PI3K/Akt/mTORC1 pathway. Accordingly, PI3K inhibition partially suppressed Glu-induced mTORC1 activation. In addition, Glu increased the phosphorylation levels of IR and IRS, and inhibiting IR downregulated the IRS/PI3K/Akt pathway. Collectively, our findings first indicate that extracellular Glu activates mTORC1 via the IR/IRS/PI3K/Akt pathway and stimulates ISC expansion, providing a new perspective for regulating the growth and health of the intestinal epithelium.


Assuntos
Ácido Glutâmico/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Mucosa Intestinal/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor de Insulina/metabolismo , Células-Tronco/metabolismo , Animais , Proteínas Substratos do Receptor de Insulina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Fosfatidilinositol 3-Quinases/genética , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética , Receptor de Insulina/genética , Transdução de Sinais , Suínos
4.
Nat Commun ; 10(1): 2692, 2019 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-31217420

RESUMO

Sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) is a lipid raft enzyme that regulates plasma membrane (PM) fluidity. Here we report that SMPDL3b excess, as observed in podocytes in diabetic kidney disease (DKD), impairs insulin receptor isoform B-dependent pro-survival insulin signaling by interfering with insulin receptor isoforms binding to caveolin-1 in the PM. SMPDL3b excess affects the production of active sphingolipids resulting in decreased ceramide-1-phosphate (C1P) content as observed in human podocytes in vitro and in kidney cortexes of diabetic db/db mice in vivo. Podocyte-specific Smpdl3b deficiency in db/db mice is sufficient to restore kidney cortex C1P content and to protect from DKD. Exogenous administration of C1P restores IR signaling in vitro and prevents established DKD progression in vivo. Taken together, we identify SMPDL3b as a modulator of insulin signaling and demonstrate that supplementation with exogenous C1P may represent a lipid therapeutic strategy to treat diabetic complications such as DKD.


Assuntos
Antígenos CD/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/metabolismo , Nefropatias Diabéticas/patologia , Insulina/metabolismo , Receptor de Insulina/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Animais , Caveolina 1/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Ceramidas/metabolismo , Ceramidas/uso terapêutico , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/genética , Nefropatias Diabéticas/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Knockout , Podócitos/citologia , Podócitos/metabolismo , Isoformas de Proteínas/metabolismo , Transdução de Sinais , Resultado do Tratamento
5.
Analyst ; 144(12): 3765-3772, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31089611

RESUMO

Investigation of the functions of insulin-secreting cells in response to glucose in single-living cells is essential for improving our knowledge on the pathogenesis of diabetes. Therefore, it is desired to develop a new convenient method that enables the direct detection of insulin secreted from single-living cells. Here, insulin-sensor-cells expressing a protein-based insulin-detecting probe immobilized on the extracellular membrane were developed to evaluate the insulin-secretion response in single-living pancreatic ß cells. The protein-based insulin-detecting probe (NαLY) was composed of a bioluminescent protein (nano-luc), the αCT segment of the insulin receptor, L1 and CR domains of the insulin receptor, and a fluorescent protein (YPet). NαLY exhibited a bioluminescence resonance energy transfer (BRET) signal in response to insulin; thus, cells of Hepa1-6 line were genetically engineered to express NαLY on the extracellular membrane. The cells were found to act as insulin-sensor-cells, exhibiting a BRET signal in response to insulin. When the insulin-sensor-cells and pancreatic ß cells (MIN6 cell line) were cocultured and stimulated with glucose, insulin-sensor-cells nearby pancreatic ß cells showed the spike-shaped BRET signal response, whereas the insulin-sensor-cells close to one pancreatic ß cell did not exhibit such signal response. However, all the insulin-sensor-cells showed a gradual increase in BRET signals, which were presumably attributed to the increase in insulin concentrations in the culture dish, confirming the function of these insulin-sensor-cells. Therefore, we demonstrated that heterogenetic insulin secretion in single-living pancreatic ß cells could be measured directly using the insulin sensor cells.


Assuntos
Técnicas de Transferência de Energia por Ressonância de Bioluminescência/métodos , Técnicas Biossensoriais/métodos , Células Secretoras de Insulina/metabolismo , Insulina/análise , Análise de Célula Única/métodos , Animais , Linhagem Celular Tumoral , Técnicas de Cocultura/métodos , Fluorescência , Glucose/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Engenharia de Proteínas/métodos , Receptor de Insulina/genética , Receptor de Insulina/metabolismo
6.
Graefes Arch Clin Exp Ophthalmol ; 257(7): 1427-1434, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31025213

RESUMO

PURPOSE: Diabetic retinopathy (DR) involves a proliferation of vascular endothelial cells and loss of pericytes. There is a link among the action of protein kinase C (PKC) and insulin signaling. Thus, we investigated the differences between these cells in insulin receptor (IR) phosphorylation in DR. METHODS: Retinas were removed from streptozotocin-induced diabetic or healthy rats, and IR expression levels were compared by immunoblot and immunohistochemistry. In vitro assays also were performed in order to determine the expressions of phosphorylated IR in both cells cultured under 5.5 or 25 mM glucose by immunoblot. Cell viability was determined in both cells cultured under different concentrations of phorbol myristate acetate (PMA), a PKC activator. To determine the involvement of the PI3 kinase pathway of IR, PMA with or without wortmannin-induced changes in Akt was also analyzed. RESULTS: Immunoreactivity to the IR was decreased in diabetic retina. High glucose (25 mM) increased phosphorylated IR levels in endothelial cells but not in pericytes. PMA (1 nM or higher) induced death of pericytes, while endothelial cells were increased. PMA increased phosphorylated Akt in endothelial cells and decreased in pericytes. Wortmannin suppressed the PMA-induced phosphorylation of Akt in endothelial cells. CONCLUSIONS: The different responses to 25 mM glucose and PMA were observed between retinal endothelial cells and pericytes. Thus, IR phosphorylation is likely important for retinal vascular cells to survive in diabetic retina.


Assuntos
Diabetes Mellitus Experimental , Retinopatia Diabética/metabolismo , Endotélio Vascular/metabolismo , Proteína Quinase C/metabolismo , Receptor de Insulina/metabolismo , Vasos Retinianos/metabolismo , Animais , Western Blotting , Proliferação de Células , Células Cultivadas , Retinopatia Diabética/patologia , Endotélio Vascular/patologia , Masculino , Fosforilação , Fotomicrografia , Ratos , Ratos Wistar , Vasos Retinianos/patologia
7.
Nat Commun ; 10(1): 1473, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30931927

RESUMO

Insulin controls glucose homeostasis and cell growth through bifurcated signaling pathways. Dysregulation of insulin signaling is linked to diabetes and cancer. The spindle checkpoint controls the fidelity of chromosome segregation during mitosis. Here, we show that insulin receptor substrate 1 and 2 (IRS1/2) cooperate with spindle checkpoint proteins to promote insulin receptor (IR) endocytosis through recruiting the clathrin adaptor complex AP2 to IR. A phosphorylation switch of IRS1/2 orchestrated by extracellular signal-regulated kinase 1 and 2 (ERK1/2) and Src homology phosphatase 2 (SHP2) ensures selective internalization of activated IR. SHP2 inhibition blocks this feedback regulation and growth-promoting IR signaling, prolongs insulin action on metabolism, and improves insulin sensitivity in mice. We propose that mitotic regulators and SHP2 promote feedback inhibition of IR, thereby limiting the duration of insulin signaling. Targeting this feedback inhibition can improve insulin sensitivity.


Assuntos
Complexo 2 de Proteínas Adaptadoras/metabolismo , Retroalimentação Fisiológica , Proteínas Substratos do Receptor de Insulina/metabolismo , Insulina/metabolismo , Sistema de Sinalização das MAP Quinases , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Receptor de Insulina/metabolismo , Animais , Endocitose , Células Hep G2 , Humanos , Resistência à Insulina , Pontos de Checagem da Fase M do Ciclo Celular , Camundongos , Fosforilação , Transdução de Sinais
8.
Chemistry ; 25(36): 8513-8521, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31012517

RESUMO

Insulin analogues, mainstays in the modern treatment of diabetes mellitus, exemplify the utility of protein engineering in molecular pharmacology. Whereas chemical syntheses of the individual A and B chains were accomplished in the early 1960s, their combination to form native insulin remains inefficient because of competing disulfide pairing and aggregation. To overcome these limitations, we envisioned an alternative approach: pairwise substitution of cysteine residues with selenocysteine (Sec, U). To this end, CysA6 and CysA11 (which form the internal intrachain A6-A11 disulfide bridge) were each replaced with Sec. The A chain[C6U, C11U] variant was prepared by solid-phase peptide synthesis; while sulfitolysis of biosynthetic human insulin provided wild-type B chain-di-S-sulfonate. The presence of selenium atoms at these sites markedly enhanced the rate and fidelity of chain combination, thus solving a long-standing challenge in chemical insulin synthesis. The affinity of the Se-insulin analogue for the lectin-purified insulin receptor was indistinguishable from that of WT-insulin. Remarkably, the thermodynamic stability of the analogue at 25 °C, as inferred from guanidine denaturation studies, was augmented (ΔΔGu ≈0.8 kcal mol-1 ). In accordance with such enhanced stability, reductive unfolding of the Se-insulin analogue and resistance to enzymatic cleavage by Glu-C protease occurred four times more slowly than that of WT-insulin. 2D-NMR and X-ray crystallographic studies demonstrated a native-like three-dimensional structure in which the diselenide bridge was accommodated in the hydrophobic core without steric clash.


Assuntos
Dissulfetos/química , Insulina/química , Selênio/química , Cristalografia por Raios X , Cisteína/química , Humanos , Insulina/genética , Insulina/metabolismo , Ligação Proteica , Dobramento de Proteína , Estabilidade Proteica , Estrutura Terciária de Proteína , Receptor de Insulina/química , Receptor de Insulina/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Selenocisteína/química , Termodinâmica
9.
Physiology (Bethesda) ; 34(3): 198-215, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30968756

RESUMO

Upon its secretion from pancreatic ß-cells, insulin reaches the liver through the portal circulation to exert its action and eventually undergo clearance in the hepatocytes. In addition to insulin secretion, hepatic insulin clearance regulates the homeostatic level of insulin that is required to reach peripheral insulin target tissues to elicit proper insulin action. Receptor-mediated insulin uptake followed by its degradation constitutes the basic mechanism of insulin clearance. Upon its phosphorylation by the insulin receptor tyrosine kinase, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) takes part in the insulin-insulin receptor complex to increase the rate of its endocytosis and targeting to the degradation pathways. This review summarizes how this process is regulated and how it is associated with insulin-degrading enzyme in the liver. It also discusses the physiological implications of impaired hepatic insulin clearance: Whereas reduced insulin clearance cooperates with increased insulin secretion to compensate for insulin resistance, it can also cause hepatic insulin resistance. Because chronic hyperinsulinemia stimulates hepatic de novo lipogenesis, impaired insulin clearance also causes hepatic steatosis. Thus impaired insulin clearance can underlie the link between hepatic insulin resistance and hepatic steatosis. Delineating these regulatory pathways should lead to building more effective therapeutic strategies against metabolic syndrome.


Assuntos
Antígenos CD/metabolismo , Moléculas de Adesão Celular/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Animais , Endocitose , Hepatócitos/metabolismo , Humanos , Insulisina/metabolismo , Receptor de Insulina/metabolismo , Transdução de Sinais
10.
Am J Chin Med ; 47(3): 675-689, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30966770

RESUMO

Pancreatic cancer cells overexpress the insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF1R). Activating these receptors, insulin and insulin-like growth factor-1 increase the growth and glycolysis of pancreatic cancer cells. The high glycolysis in pancreatic cancer cells increases whole-body energy expenditure and is therefore involved in the pathogenesis of cancer cachexia. The antagonism of IR and IGF1R may sabotage pancreatic cancer cells and attenuate cancer cachexia. Previous studies have shown that the intracellular regulating system of IR/IGF1R may be functionally interrelated to another intracellular system whose master regulator is hypoxia-inducible factor-1 (HIF-1). In this study, we investigated how the IR/IGF1R and HIF-1 systems are interrelated in pancreatic cancer cells. We also investigated whether a phytochemical, penta-O-galloyl- ß -D-glucose ( ß -PGG), antagonizes IR/IGF1R, sabotages pancreatic cancer cells and alleviates cancer cachexia. We found in MiaPaCa2 pancreatic cancer cells that IR/IGF1R activation increased both the α -subunit of HIF-1 and caveolin-1. This result suggests that IR/IGF1R, HIF-1 α , and caveolin-1 may constitute a feed-forward loop to mediate the effect of IR/IGF1R activation. ß -PGG inhibited IR/IGF1R activity and decreased glycolytic enzymes in MiaPaCa2 and Panc-1 pancreatic cancer cells. When MiaPaCa2 cells were transplanted in athymic mice, their growth was inhibited by ß -PGG or by a HIF-1 α inhibitor, rhein. ß -PGG and rhein also decreased glycolytic enzymes in the tumor grafts and reduced liver gluconeogenesis, skeletal-muscle proteolysis and fat lipolysis in the tumor carriers. Cancer-induced body-weight loss, however, was prevented by ß -PGG but not rhein. In conclusion, ß -PGG combats pancreatic cancer cells and cures cancer cachexia.


Assuntos
Caquexia/tratamento farmacológico , Taninos Hidrolisáveis/farmacologia , Taninos Hidrolisáveis/uso terapêutico , Neoplasias Pancreáticas/metabolismo , Animais , Caquexia/etiologia , Caveolina 1/metabolismo , Glicólise , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Transplante de Neoplasias , Neoplasias Pancreáticas/complicações , Receptor de Insulina/antagonistas & inibidores , Receptor de Insulina/metabolismo , Receptores de Somatomedina/antagonistas & inibidores , Receptores de Somatomedina/metabolismo , Células Tumorais Cultivadas
11.
EBioMedicine ; 42: 188-202, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30922963

RESUMO

BACKGROUND: Activation of brain insulin receptors modulates reward sensitivity, inhibitory control and memory. Variations in the functioning of this mechanism likely associate with individual differences in the risk for related mental disorders (attention deficit hyperactivity disorder or ADHD, addiction, dementia), in agreement with the high co-morbidity between insulin resistance and psychopathology. These neurobiological mechanisms can be explored using genetic studies. We propose a novel, biologically informed genetic score reflecting the mesocorticolimbic and hippocampal insulin receptor-related gene networks, and investigate if it predicts endophenotypes (impulsivity, cognitive ability) in community samples of children, and psychopathology (addiction, dementia) in adults. METHODS: Lists of genes co-expressed with the insulin receptor in the mesocorticolimbic system or hippocampus were created. SNPs from these genes (post-clumping) were compiled in a polygenic score using the association betas described in a conventional GWAS (ADHD in the mesocorticolimbic score and Alzheimer in the hippocampal score). Across multiple samples (n = 4502), the biologically informed, mesocorticolimbic or hippocampal specific insulin receptor polygenic scores were calculated, and their ability to predict impulsivity, risk for addiction, cognitive performance and presence of Alzheimer's disease was investigated. FINDINGS: The biologically-informed ePRS-IR score showed better prediction of child impulsivity and cognitive performance, as well as risk for addiction and Alzheimer's disease in comparison to conventional polygenic scores for ADHD, addiction and dementia. INTERPRETATION: This novel, biologically-informed approach enables the use of genomic datasets to probe relevant biological processes involved in neural function and disorders. FUND: Toxic Stress Research network of the JPB Foundation, Jacobs Foundation (Switzerland), Sackler Foundation.


Assuntos
Encéfalo/metabolismo , Endofenótipos , Estudos de Associação Genética , Predisposição Genética para Doença , Receptor de Insulina/genética , Encéfalo/fisiopatologia , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Estudo de Associação Genômica Ampla , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Humanos , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único , Receptor de Insulina/metabolismo , Reprodutibilidade dos Testes
12.
Nutrients ; 11(3)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875994

RESUMO

Inulin is considered an efficient prebiotic and is beneficial for metabolic diseases via promoting intestinal probiotic enrichment and the metabolites of short-chain fatty acids (SCFAs). However, the effect of inulin on patients with InR deficiencies has seldom been reported. In this study, the lifespan, related gene expression, and gut microbiota of InRp5545/TM3 (insulin receptor mutant) Drosophila melanogaster under inulin treatment were investigated. The results showed that the lifespan was extended in only males and not in females. Furthermore, distinctly different patterns of gene expression were found between males and females, especially in the insulin/insulin-like growth factor (IGF)-like signalling (IIS) and target of rapamycin (TOR) pathways. Additionally, as a link between inulin and lifespan responses, the gut microbiota was distinctly separated by gender in both the standard diet group and the inulin treatment group, and the relationship between lifespan and the gut microbiota community was stronger in male flies than in females. This study provides preliminary evidence for the gender-dependent lifespan responses to inulin in insulin signalling-deficient Drosophila. However, controls such as wild-type and TM3 flies, and more InR mutant strains with different genetic backgrounds need to be further investigated to elucidate the mechanisms underlying the phenomenon.


Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Inulina/farmacologia , Longevidade/efeitos dos fármacos , Animais , Drosophila melanogaster , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Masculino , Mutação/genética , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Transdução de Sinais/efeitos dos fármacos
13.
Bull Exp Biol Med ; 166(5): 641-645, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30903488

RESUMO

Metastatic cascade is associated with the process of epithelial-mesenchymal transition accompanied by changes in cell proliferation, migration, adhesion, and invasiveness mediated by the insulin-like growth factor (IGF) signal pathway. IGFBP6 protein binds IGF and prevents its interaction with receptors. IGFBP6 gene knockdown through RNA-interference inhibits cell migration and increased the rate of proliferation of breast cancer MDA-MB-231 cells. IGFBP6 knockdown cells are characterized by increased expression of MIR100 and MIRLET7A2 genes encoding hsa-miR-100-3p, hsa-miR-100-5p, hsa-let-7a-5p, and hsa-let-7a-2-3p miRNA. The target genes of these microRNAs are IGF2, IGF1R, INSR, and CCND1 associated with IGF signaling pathway and proliferative and migratory activity during the metastatic cascade. A significant decrease in the expression of INSR and CCND1 genes was demonstrated by PCR and microarray analysis.


Assuntos
Antígenos CD/metabolismo , Ciclina D1/metabolismo , MicroRNAs/metabolismo , Receptor de Insulina/metabolismo , Receptores de Somatomedina/metabolismo , Antígenos CD/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Movimento Celular/fisiologia , Proliferação de Células/genética , Proliferação de Células/fisiologia , Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes , Humanos , MicroRNAs/genética , Receptor de Insulina/genética , Receptores de Somatomedina/genética
14.
Int J Mol Sci ; 20(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875909

RESUMO

Insulin exists in the central nervous system, where it executes two important functions in the hypothalamus: the suppression of food intake and the improvement of glucose metabolism. Recent studies have shown that both are exerted robustly in rodents and humans. If intact, these functions exert beneficial effects on obesity and diabetes, respectively. Disruption of both occurs due to a condition known as hypothalamic insulin resistance, which is caused by obesity and the overconsumption of saturated fat. An enormous volume of literature addresses the molecular mechanisms of hypothalamic insulin resistance. IKKß and JNK are major players in the inflammation pathway, which is activated by saturated fatty acids that induce hypothalamic insulin resistance. Two major tyrosine phosphatases, PTP-1B and TCPTP, are upregulated in chronic overeating. They dephosphorylate the insulin receptor and insulin receptor substrate proteins, resulting in hypothalamic insulin resistance. Prolonged hyperinsulinemia with excessive nutrition activates the mTOR/S6 kinase pathway, thereby enhancing IRS-1 serine phosphorylation to induce hypothalamic insulin resistance. Other mechanisms associated with this condition include hypothalamic gliosis and disturbed insulin transport into the central nervous system. Unveiling the precise molecular mechanisms involved in hypothalamic insulin resistance is important for developing new ways of treating obesity and type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Hipotálamo/metabolismo , Resistência à Insulina , Obesidade/complicações , Transdução de Sinais , Animais , Diabetes Mellitus Tipo 2/imunologia , Ingestão de Alimentos , Humanos , Quinase I-kappa B/metabolismo , MAP Quinase Quinase 4/metabolismo , Obesidade/imunologia , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 2/metabolismo , Receptor de Insulina/metabolismo , Regulação para Cima
15.
PLoS Biol ; 17(3): e3000189, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30893295

RESUMO

Insulin resistance and obesity are associated with reduced gonadotropin-releasing hormone (GnRH) release and infertility. Mice that lack insulin receptors (IRs) throughout development in both neuronal and non-neuronal brain cells are known to exhibit subfertility due to hypogonadotropic hypogonadism. However, attempts to recapitulate this phenotype by targeting specific neurons have failed. To determine whether astrocytic insulin sensing plays a role in the regulation of fertility, we generated mice lacking IRs in astrocytes (astrocyte-specific insulin receptor deletion [IRKOGFAP] mice). IRKOGFAP males and females showed a delay in balanopreputial separation or vaginal opening and first estrous, respectively. In adulthood, IRKOGFAP female mice also exhibited longer, irregular estrus cycles, decreased pregnancy rates, and reduced litter sizes. IRKOGFAP mice show normal sexual behavior but hypothalamic-pituitary-gonadotropin (HPG) axis dysregulation, likely explaining their low fecundity. Histological examination of testes and ovaries showed impaired spermatogenesis and ovarian follicle maturation. Finally, reduced prostaglandin E synthase 2 (PGES2) levels were found in astrocytes isolated from these mice, suggesting a mechanism for low GnRH/luteinizing hormone (LH) secretion. These findings demonstrate that insulin sensing by astrocytes is indispensable for the function of the reproductive axis. Additional work is needed to elucidate the role of astrocytes in the maturation of hypothalamic reproductive circuits.


Assuntos
Astrócitos/metabolismo , Receptor de Insulina/metabolismo , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Prostaglandina-E Sintases/metabolismo , Puberdade Tardia/metabolismo
16.
Cell Prolif ; 52(3): e12575, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30838710

RESUMO

OBJECTIVES: Hyperinsulinemia is a risk factor for pancreatic cancer, but the function of insulin in carcinogenesis is unclear, so this study aimed to elucidate the carcinogenic effects of insulin and the synergistic effect with the KRAS mutation in the early stage of pancreatic cancer. MATERIALS AND METHODS: A pair of immortalized human pancreatic duct-derived cells, hTERT-HPNE E6/E7/st (HPNE) and its oncogenic KRASG12D variant, hTERT-HPNE E6/E7/KRASG12D /st (HPNE-mut-KRAS), were used to investigate the effect of insulin. Cell proliferation, migration and invasion were assessed using Cell Counting Kit-8 and transwell assays, respectively. The expression of E-cadherin, N-cadherin, vimentin and matrix metalloproteinases (MMP-2, MMP-7 and MMP-9) was evaluated by Western blotting and/or qRT-PCR. The gelatinase activity of MMP-2 and MMP-9 in conditioned media was detected using gelatin zymography. The phosphorylation status of AKT, GSK3ß, p38, JNK and ERK1/2 MAPK was determined by Western blotting. RESULTS: The migration and invasion ability of HPNE cells was increased after the introduction of the mutated KRAS gene, together with an increased expression of MMP-2. These effects were further enhanced by the simultaneous administration of insulin. The use of MMP-2 siRNA confirmed that MMP-2 was involved in the regulation of cell invasion. Furthermore, there was a concentration- and time-dependent increase in gelatinase activity after insulin treatment, which could be reversed by an insulin receptor tyrosine kinase inhibitor (HNMPA-(AM)3 ). In addition, insulin markedly enhanced the phosphorylation of PI3K/AKT, p38, JNK and ERK1/2 MAPK pathways, with wortmannin or LY294002 (a PI3K-specific inhibitor) and PD98059 (a MEK1-specific inhibitor) significantly inhibiting the insulin-induced increase in MMP-2 gelatinolytic activity. CONCLUSIONS: Taken together, these results suggest that insulin induced migration and invasion in HPNE and HPNE-mut-KRAS through PI3K/AKT and ERK1/2 activation, with MMP-2 gelatinolytic activity playing a vital role in this process. These findings may provide a new therapeutic target for preventing carcinogenesis and the evolution of pancreatic cancer with a background of hyperinsulinemia.


Assuntos
Insulina/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Antígenos CD/metabolismo , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Insulina/farmacologia , Sistema de Sinalização das MAP Quinases , Metaloproteinase 2 da Matriz/genética , Modelos Biológicos , Invasividade Neoplásica , Ductos Pancreáticos/citologia , Ductos Pancreáticos/metabolismo , Neoplasias Pancreáticas/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Mutação Puntual , RNA Interferente Pequeno/genética , Receptor de Insulina/metabolismo , Transdução de Sinais , Regulação para Cima
17.
Chemosphere ; 224: 71-76, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30818196

RESUMO

Fluoride is one of the common environmental pollutants. Internal exposure to fluoride is related to the lowered cognitive function and intelligence, particularly for children. Determination of protein content in brain tissue is a means to reflect the functional development of the central nervous system. Insulin and insulin receptor (IR) signaling systems are associated with cognitive ability. The present research focused on the assessment of the expressions of IR protein and mRNA in hippocampus and olfactory bulb (OB), as well as learning and memory ability of male Kunming mice. Mice were exposed to 50, 100, and 150 mg/L NaF for 90 continuous days. The results showed that learning and memory abilities as well as protein content of male mice brain was significantly decreased by fluoride. Fluoride could inhibit the protein and mRNA expressions of the IR in the hippocampus and OB of mice. IRs mainly distributed in the olfactory nerve layer of the outermost layer of the OB, and most distributed in the hippocampal cornu ammon 3 (CA3) region, followed by the dentate gyrus (DG) and cornu ammon 1 (CA1) regions. These findings suggested that inhibition of the IR protein and mRNA expressions in the hippocampus and OB by fluoride might in part affect learning and memory ability in male mice.


Assuntos
Fluoretos/toxicidade , Hipocampo/fisiopatologia , Aprendizagem/efeitos dos fármacos , Bulbo Olfatório/fisiopatologia , Receptor de Insulina/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Fluoretos/metabolismo , Hipocampo/metabolismo , Masculino , Memória/efeitos dos fármacos , Camundongos , Bulbo Olfatório/metabolismo , RNA Mensageiro/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/metabolismo
18.
Growth Horm IGF Res ; 45: 25-30, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30825797

RESUMO

Insulin (IR) and insulin-like growth factor I (IGF-IR) receptors share structural homology and can form hybrid heterodimers. While different observations suggest that hybrid receptors are important in physiology and pathology, little is known about their function in the brain. To gain further insight into the role of IR/IGF-IR hybrids in this organ, we analyzed their cellular distribution in the mouse brain. We combined proximity ligation assays (PLA) for IR and IGF-IR, a technique that detects close protein-protein interactions, with immunocytochemistry for brain cell markers to identify IR/IGF-IR hybrids in the major types of brain cells. Intriguingly, while all the types of brain cells analyzed co-express both receptors, only neurons, astroglia, and microglia show readily detectable IR/IGF-IR hybrids. Hybrid PLA signal was negligible in brain endothelial cells and was absent in oligodendrocytes. Hybrids were comparatively more abundant in neurons and peaked after brain development was completed. Cell-specific expression and greater abundance in the adult brain suggests specialized actions of IR/IGF-IR hybrids in this organ, particularly in neurons.


Assuntos
Astrócitos/metabolismo , Encéfalo/metabolismo , Microglia/metabolismo , Neurônios/metabolismo , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/metabolismo , Animais , Astrócitos/citologia , Encéfalo/citologia , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/citologia , Neurônios/citologia , Multimerização Proteica , Receptor IGF Tipo 1/genética , Receptor de Insulina/genética
19.
Proc Natl Acad Sci U S A ; 116(13): 6379-6384, 2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30765523

RESUMO

Previous studies have shown that insulin and IGF-1 signaling in the brain, especially the hypothalamus, is important for regulation of systemic metabolism. Here, we develop mice in which we have specifically inactivated both insulin receptors (IRs) and IGF-1 receptors (IGF1Rs) in the hippocampus (Hippo-DKO) or central amygdala (CeA-DKO) by stereotaxic delivery of AAV-Cre into IRlox/lox/IGF1Rlox/lox mice. Consequently, both Hippo-DKO and CeA-DKO mice have decreased levels of the GluA1 subunit of glutamate AMPA receptor and display increased anxiety-like behavior, impaired cognition, and metabolic abnormalities, including glucose intolerance. Hippo-DKO mice also display abnormal spatial learning and memory whereas CeA-DKO mice have impaired cold-induced thermogenesis. Thus, insulin/IGF-1 signaling has common roles in the hippocampus and central amygdala, affecting synaptic function, systemic glucose homeostasis, behavior, and cognition. In addition, in the hippocampus, insulin/IGF-1 signaling is important for spatial learning and memory whereas insulin/IGF-1 signaling in the central amygdala controls thermogenesis via regulation of neural circuits innervating interscapular brown adipose tissue.


Assuntos
Comportamento Animal , Núcleo Central da Amígdala/metabolismo , Hipocampo/metabolismo , Insulina/metabolismo , Transdução de Sinais , Tecido Adiposo Marrom/metabolismo , Animais , Ansiedade , Encefalopatias Metabólicas , Glucose/metabolismo , Intolerância à Glucose , Homeostase , Fator de Crescimento Insulin-Like I/metabolismo , Memória , Camundongos , Camundongos Knockout , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/metabolismo , Aprendizagem Espacial , Termogênese
20.
Int J Mol Sci ; 20(3)2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30754657

RESUMO

Insulin is a major endocrine hormone also involved in the regulation of energy and lipid metabolism via the activation of an intracellular signaling cascade involving the insulin receptor (INSR), insulin receptor substrate (IRS) proteins, phosphoinositol 3-kinase (PI3K) and protein kinase B (AKT). Specifically, insulin regulates several aspects of the development and function of adipose tissue and stimulates the differentiation program of adipose cells. Insulin can activate its responses in adipose tissue through two INSR splicing variants: INSR-A, which is predominantly expressed in mesenchymal and less-differentiated cells and mainly linked to cell proliferation, and INSR-B, which is more expressed in terminally differentiated cells and coupled to metabolic effects. Recent findings have revealed that different distributions of INSR and an altered INSR-A:INSR-B ratio may contribute to metabolic abnormalities during the onset of insulin resistance and the progression to type 2 diabetes. In this review, we discuss the role of insulin and the INSR in the development and endocrine activity of adipose tissue and the pharmacological implications for the management of obesity and type 2 diabetes.


Assuntos
Tecido Adiposo/metabolismo , Metabolismo Energético , Insulina/metabolismo , Organogênese , Receptor de Insulina/metabolismo , Animais , Humanos , Receptores de Somatomedina/metabolismo
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