Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.547
Filtrar
1.
Endocrinology ; 161(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31748790

RESUMO

Decidualization, the process by which fibroblastic human endometrial stromal cells (HESC) differentiate into secretory decidual cells, is a critical event during the establishment of pregnancy. It is dependent on the steroid hormone progesterone acting through the nuclear progesterone receptor (PR). Previously, we identified insulin receptor substrate 2 (IRS2) as a factor that is directly regulated by PR during decidualization. IRS2 is an adaptor protein that functionally links receptor tyrosine kinases, such as insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R), and their downstream effectors. IRS2 expression was induced in HESC during in vitro decidualization and siRNA-mediated downregulation of IRS2 transcripts resulted in attenuation of this process. Further use of siRNAs targeted to IR or IGF1R transcripts showed that downregulation of IR, but not IGF1R, led to impaired decidualization. Loss of IRS2 transcripts in HESC suppressed phosphorylation of both ERK1/2 and AKT, downstream effectors of insulin signaling, which mediate gene expression associated with decidualization and regulate glucose uptake. Indeed, downregulation of IRS2 resulted in reduced expression and membrane localization of the glucose transporters GLUT1 and GLUT4, resulting in lowered glucose uptake during stromal decidualization. Collectively, these data suggest that the PR-regulated expression of IRS2 is necessary for proper insulin signaling for controlling gene expression and glucose utilization, which critically support the decidualization process to facilitate pregnancy. This study provides new insight into the mechanisms by which steroid hormone signaling intersects with insulin signaling in the uterus during decidualization, which has important implications for pregnancy complications associated with insulin resistance and infertility.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Decídua/efeitos dos fármacos , Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina , Progesterona/farmacologia , Diferenciação Celular/genética , Células Cultivadas , Decídua/citologia , Decídua/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Facilitadoras de Transporte de Glucose/genética , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Fosforilação/efeitos dos fármacos , Gravidez , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Células Estromais/citologia , Células Estromais/metabolismo , Útero/citologia , Útero/metabolismo
2.
J Food Sci ; 84(10): 3045-3053, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31529802

RESUMO

Insulin resistance (IR) and inflammatory mediators are correlated with hepatic fibrosis. Quercetin is a bioflavonoid with well-known antidiabetic and antifibrotic properties. Bile duct ligation (BDL) is a surgical model performed on animals to produce a murine model in which increased oxidative stress occurs, which results in liver fibrosis. Our study aimed to determine whether quercetin improves hepatic IR as well as hepatic fibrosis in rats experiencing BDL. Male Wistar rats were allocated to four groups according to a random pattern, including a sham group, a sham and quercetin group (30 mg/kg/day), a BDL alone group, and a BDL and quercetin group (30 mg/kg/day). Evaluation of STAT3, SOCS3, IRS1, Rac1, Rac1-GTP, Sp1, NOX1, HIF-1α, and ERK1 expression was performed by RT-PCR along with the western blot analytical technique in liver tissue. The antidiabetic impact of quercetin was associated with reduction in mRNA and expression of protein in STAT3 and SOCS3, along with an increase in IRS1. The antifibrotic effect of quercetin was also determined by downregulation of mRNA or the levels of protein expression of Rac1-GTP, Rac1, HIF-1α, NOX1, and Sp1, along with ERK1. Our study indicates that quercetin may improve hepatic fibrosis via inhibiting ROS-associated inflammation as well as ameliorating hepatic IR by beneficial regulation of the STAT3/SOCS3/IRS1 signaling pathway.


Assuntos
Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina , Cirrose Hepática/tratamento farmacológico , Quercetina/administração & dosagem , Fator de Transcrição STAT3/metabolismo , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Animais , Ductos Biliares/cirurgia , Regulação para Baixo/efeitos dos fármacos , Proteínas Substratos do Receptor de Insulina/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Cirrose Hepática/genética , Cirrose Hepática/metabolismo , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Fator de Transcrição STAT3/genética , Transdução de Sinais/efeitos dos fármacos , Proteína 3 Supressora da Sinalização de Citocinas/genética
3.
J Agric Food Chem ; 67(42): 11657-11664, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31549821

RESUMO

The therapeutic benefits of whole grains on diabetes mellitus have been continuously confirmed by in-depth research. To date, limited studies have investigated the effect of extruded products of whole grains on the insulin signaling pathway in vivo. This study investigated the effects of oral consumption of whole grain extrudate, including 97% brown rice and 3% defatted rice bran (w/w, BRD), on glucose metabolism and the hepatic insulin signaling pathway in C57BL/KsJ-db/db mice. BRD treatment induced a remarkable reduction in blood glucose. Moreover, glucose intolerance and insulin resistance were ameliorated in the BRD-treated group compared with those in the db/db control group. BRD also increased the hepatic glycogen content by reducing the expression and increasing the phosphorylation of glycogen synthase kinase 3ß (GSK3ß). The activities of glucose-6-phosphatase and phosphoenolpyruvate carboxylase and their respective mRNA expression levels in the liver were simultaneously decreased in the BRD-treated group. BRD also significantly upregulated the expression of phosphatidylinositol 3-kinase (PI3K) and increased the phosphorylation of insulin receptor substrate 1 (IRS1) and protein kinase B (AKT). These results indicate that BRD exhibits antidiabetic potential by activating the IRS1/PI3K/AKT signaling pathway, further regulating the expression of the FOXO1 gene and p-GSK3ß protein, thus inhibiting hepatic gluconeogenesis, increasing hepatic glycogen storage, and improving insulin resistance. Therefore, BRD could be used as a functional ingredient to alleviate the symptoms of hyperglycemia.


Assuntos
Diabetes Mellitus Tipo 2/dietoterapia , Proteínas Substratos do Receptor de Insulina/metabolismo , Insulina/metabolismo , Oryza/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Teste de Tolerância a Glucose , Glicogênio Sintase Quinase 3 beta/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Oryza/química , Fosfatidilinositol 3-Quinase/genética , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/efeitos dos fármacos
4.
Mol Cell Biol ; 39(22)2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31501273

RESUMO

Brain insulin resistance is a key pathological feature contributing to obesity, diabetes, and neurodegenerative disorders, including Alzheimer's disease (AD). Besides the classic transcriptional mechanism mediated by hormones, posttranscriptional regulation has recently been shown to regulate a number of signaling pathways that could lead to metabolic diseases. Here, we show that microRNA 7 (miR-7), an abundant microRNA in the brain, targets insulin receptor (INSR), insulin receptor substrate 2 (IRS-2), and insulin-degrading enzyme (IDE), key regulators of insulin homeostatic functions in the central nervous system (CNS) and the pathology of AD. In this study, we found that insulin and liver X receptor (LXR) activators promote the expression of the intronic miR-7-1 in vitro and in vivo, along with its host heterogeneous nuclear ribonucleoprotein K (HNRNPK) gene, encoding an RNA binding protein (RBP) that is involved in insulin action at the posttranscriptional level. Our data show that miR-7 expression is altered in the brains of diet-induced obese mice. Moreover, we found that the levels of miR-7 are also elevated in brains of AD patients; this inversely correlates with the expression of its target genes IRS-2 and IDE. Furthermore, overexpression of miR-7 increased the levels of extracellular Aß in neuronal cells and impaired the clearance of extracellular Aß by microglial cells. Taken together, these results represent a novel branch of insulin action through the HNRNPK-miR-7 axis and highlight the possible implication of these posttranscriptional regulators in a range of diseases underlying metabolic dysregulation in the brain, from diabetes to Alzheimer's disease.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Insulina/metabolismo , Receptores X do Fígado/metabolismo , MicroRNAs/metabolismo , Receptor de Insulina/metabolismo , Animais , Encéfalo/metabolismo , Linhagem Celular Tumoral , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/metabolismo , Humanos , Insulina/genética , Resistência à Insulina , Insulisina/metabolismo , Receptores X do Fígado/genética , Camundongos , MicroRNAs/genética , Neurônios/metabolismo , Processamento Pós-Transcricional do RNA , Receptor de Insulina/genética , Transdução de Sinais
5.
Invest Ophthalmol Vis Sci ; 60(12): 3786-3793, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31504080

RESUMO

Purpose: Light-emitting diodes that emit high-intensity blue light are associated with blue-light hazard. Here, we report that blue light disturbs circadian rhythms by interfering with the clock gene in the suprachiasmatic nucleus (SCN) and that suppression of blue light at night ameliorates metabolic abnormalities by controlling circadian rhythms. Methods: C57BL/6J mice were exposed to 10-lux light for 30 minutes at Zeitgeber time 14 for light pulse with blue light or blue-light cut light to induce phase shift of circadian rhythms. Phase shift, clock gene expression in SCN, and metabolic parameters were analyzed. In the clinical study, healthy participants wore blue-light shield eyewear for 2 to 3 hours before bed. Anthropometric data analyses, laboratory tests, and sleep quality questionnaires were performed before and after the study. Results: In mice, phase shift induced with a blue-light cut light pulse was significantly shorter than that induced with a white light pulse. The phase of Per2 expression in the SCN was also delayed after a white light pulse. Moreover, blood glucose levels 48 hours after the white light pulse were higher than those after the blue-cut light pulse. Irs2 expression in the liver was decreased with white light but significantly recovered with the blue-cut light pulse. In a clinical study, after 1 month of wearing blue-light shield eyeglasses, there were improvements in fasting plasma glucose levels, insulin resistance, and sleep quality. Conclusions: Our results suggest that suppression of blue light at night effectively maintains circadian rhythms and metabolism.


Assuntos
Glicemia/metabolismo , Ritmo Circadiano/efeitos da radiação , Luz , Metabolismo dos Lipídeos/fisiologia , Proteção Radiológica , Sono/fisiologia , Adulto , Animais , Antropometria , Proteínas CLOCK/genética , Regulação da Expressão Gênica/fisiologia , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Fígado/metabolismo , Masculino , Melatonina/urina , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Atividade Motora , Reação em Cadeia da Polimerase em Tempo Real , Núcleo Supraquiasmático/metabolismo , Inquéritos e Questionários
6.
Pol J Vet Sci ; 22(3): 589-598, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31560477

RESUMO

Insulin receptor substrate 2 (IRS-2) modulates the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which controls the suppression of gluconeogenic genes; IRS-2 is also a critical node of insulin signaling. Because of the high homology between pig and human IRS-2, we investigated the expression pattern and function of porcine IRS-2. QPCR and immunoblotting were used to detect the IRS-2 expression level in different tissues. There were high IRS-2 levels in the cerebral cortex, hypothalamus, and cerebellum in the central nervous system. In peripheral tissues, IRS-2 was expressed at relatively high levels in the liver. Immunohistochemistry analysis revealed that IRS-2 was mainly distributed in the hypothalamus and cerebral cortex. Furthermore, IRS-2 knockdown porcine hepatocytes and porcine aortic endothelial cells (PAECs) were generated. The IRS-2 knockdown induced abnormal expression of genes involved in glycolipid metabolism in hepatocytes and reduced the antiatherosclerosis ability in PAECs. In addition, we disrupted IRS-2 in porcine embryonic fibroblasts (PEFs) using the CRISPR/Cas9 genome editing system, before finally generating IRS-2 knockout embryos by somatic cell nuclear transfer (SCNT). Taken together, our results indicate that IRS-2 might be a valuable target to establish diabetes and vascular disease models in the pig.


Assuntos
Células Endoteliais/metabolismo , Hepatócitos/metabolismo , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/metabolismo , Suínos , Animais , Aorta , Clonagem Molecular , Proteínas Substratos do Receptor de Insulina/química , Distribuição Tecidual
7.
Med Sci Monit ; 25: 6719-6726, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31493329

RESUMO

BACKGROUND Bariatric procedures such as left gastric artery ligation (LGAL) and sleeve gastrectomy (SG) have emerged as important procedures for treating morbid obesity. In this study, we compared the effects of LGAL vs. SG on obesity-induced adipose tissue macrophage infiltration and inflammation in diet-induced obese rats. MATERIAL AND METHODS Sprague-Dawley (SD) rats were fed a high-fat diet (HFD) for 16 weeks to induce obesity. SG, GLAL, or corresponding sham surgeries were performed in anesthetized rats. Inflammatory factor expression in serum and epididymal and retroperitoneal adipose tissues were analyzed 4 weeks after surgery. Macrophage infiltration and phenotype transformation were also assessed with Western blot analysis and immunofluorescence. RESULTS Both LGAL and SG strongly attenuated high-fat diet (HFD)-induced fat accumulation in retroperitoneal and epididymal tissues. The expressions of inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and monocyte chemoattractant protein (MCP)-1 were downregulated after LGAL and after SG by promoting activation of M2 macrophages, despite continued exposure to HFD. Furthermore, both LGAL and SG resulted in increased macrophage infiltration, but did not contribute to phenotype transformation of macrophages to M1. CONCLUSIONS LGAL and SG both reduced fat accumulation caused by HFD feeding. Therapies designed to ameliorate the inflammatory response by promoting activation of M2 macrophages may be valuable.


Assuntos
Tecido Adiposo/patologia , Dieta Hiperlipídica , Gastrectomia , Artéria Gástrica/ultraestrutura , Inflamação/patologia , Macrófagos/patologia , Obesidade/patologia , Animais , Epididimo/patologia , Mediadores da Inflamação/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Ligadura , Masculino , NF-kappa B/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais
8.
J Diabetes Res ; 2019: 4021623, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396538

RESUMO

Background: It has been suggested that visfatin, which is an adipocytokine, exhibits proinflammatory properties and is associated with insulin resistance. Insulin resistance and inflammation are the principal pathogeneses of nonalcoholic fatty liver disease (NAFLD), but the relationship, if any, between visfatin and NAFLD remains unclear. Here, we evaluated the effects of visfatin on hepatic inflammation and insulin resistance in HepG2 cells and examined the molecular mechanisms involved. Methods: After treatment with visfatin, the inflammatory cytokines IL-6, TNF-α, and IL-1ß were assessed by real-time polymerase chain reaction (RT-PCR) and immunocytochemical staining in HepG2 cells. To investigate the effects of visfatin on insulin resistance, we evaluated insulin-signaling pathways, such as IR, IRS-1, GSK, and AKT using immunoblotting. We assessed the intracellular signaling molecules including STAT3, NF-κB, IKK, p38, JNK, and ERK by western blotting. We treated HepG2 cells with both visfatin and either AG490 (a JAK2 inhibitor) or Bay 7082 (an NF-κB inhibitor); we examined proinflammatory cytokine mRNA levels using RT-PCR and insulin signaling using western blotting. Results: In HepG2 cells, visfatin significantly increased the levels of proinflammatory cytokines, reduced the levels of proteins (e.g., phospho-IR, phospho-IRS-1 (Tyr612), phospho-AKT, and phospho-GSK-3α/ß) involved in insulin signaling, and increased IRS-1 S307 phosphorylation compared to controls. Interestingly, visfatin increased the activities of the JAK2/STAT3 and IKK/NF-κB signaling pathways but not those of the JNK, p38, and ERK pathways. Visfatin-induced inflammation and insulin resistance were regulated by JAK2/STAT3 and IKK/NF-κB signaling; together with AG490 or Bay 7082, visfatin significantly reduced mRNA levels of IL-6, TNF-α and IL-1ß and rescued insulin signaling. Conclusion: Visfatin induced proinflammatory cytokine production and inhibited insulin signaling via the STAT3 and NF-κB pathways in HepG2 cells.


Assuntos
Hepatócitos/efeitos dos fármacos , Inflamação/induzido quimicamente , Resistência à Insulina , NF-kappa B/metabolismo , Nicotinamida Fosforribosiltransferase/farmacologia , Fator de Transcrição STAT3/metabolismo , Citocinas/genética , Citocinas/metabolismo , Células Hep G2 , Hepatócitos/metabolismo , Humanos , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina/fisiologia , Fator de Transcrição STAT3/genética , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
9.
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
10.
Nat Methods ; 16(8): 703-706, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31363206

RESUMO

Proteins can be phosphorylated at neighboring sites resulting in different functional states, and studying the regulation of these sites has been challenging. Here we present Thesaurus, a search engine that detects and quantifies phosphopeptide positional isomers from parallel reaction monitoring and data-independent acquisition mass spectrometry experiments. We apply Thesaurus to analyze phosphorylation events in the PI3K/AKT signaling pathway and show neighboring sites with distinct regulation.


Assuntos
Fosfopeptídeos/análise , Fosfoproteínas/análise , Proteoma/análise , Ferramenta de Busca/métodos , Células HeLa , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Isomerismo , Células MCF-7 , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Espectrometria de Massas em Tandem
11.
Food Funct ; 10(9): 5853-5862, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31464308

RESUMO

Gymnemic acid (GA) is a naturally occurring herbal ingredient that improves glucose metabolism in patients with diabetes mellitus. In this study, we evaluated the ameliorative effects of GA on obesity-induced inflammation and insulin resistance (IR), and identified the mechanisms for these effects in db/db mice. In these mice, GA effectively lowered fasting blood glucose concentrations from 26.3 ± 4.09 to 17.4 ± 3.38 mmol L-1, and improved oral glucose and insulin tolerance. Furthermore, GA treatment accelerated lipid transport and promoted fatty acid oxidation, which reduced lipid accumulation and inhibited expression of inflammatory cytokines, including those involved in the proliferator-activated receptor δ (PPARδ)- and nuclear factor κB (NFκB)-mediated signaling pathways. In addition, the anti-inflammatory effects increased the ratio of insulin to glucagon. It also regulated the insulin signal transduction with reduced phosphorylation of IRS-1 (Ser) and increased phosphorylation of IRS (Tyr) in liver, skeletal muscle and adipose tissue. In summary, we demonstrated in db/db mice that GA induces fatty acid oxidation, and alleviates inflammation and IR in liver, skeletal muscle and adipose tissue through PPARδ- and NFκB-mediated signaling pathways.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Resistência à Insulina , Insulina/metabolismo , NF-kappa B/imunologia , PPAR delta/imunologia , Saponinas/administração & dosagem , Triterpenos/administração & dosagem , Animais , Diabetes Mellitus/genética , Diabetes Mellitus/imunologia , Diabetes Mellitus/metabolismo , Modelos Animais de Doenças , Glucose/metabolismo , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Fígado/efeitos dos fármacos , Fígado/imunologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/imunologia , Músculo Esquelético/metabolismo , NF-kappa B/genética , PPAR delta/genética , Transdução de Sinais
12.
Nutrients ; 11(8)2019 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-31426549

RESUMO

The biological effects of insulin signaling are regulated by the phosphorylation of insulin receptor substrate 1 (IRS1) at serine (Ser) residues. In the brain, phosphorylation of IRS1 at specific Ser sites increases in patients with Alzheimer's disease (AD) and its animal models. However, whether the activation of Ser sites on neural IRS1 is related to any type of memory decline remains unclear. Here, we show the modifications of IRS1 through its phosphorylation at etiology-specific Ser sites in various animal models of memory decline, such as diabetic, aged, and amyloid precursor protein (APP) knock-in NL-G-F (APPKINL-G-F) mice. Substantial phosphorylation of IRS1 at specific Ser sites occurs in type 2 diabetes- or age-related memory deficits independently of amyloid-ß (Aß). Furthermore, we present the first evidence that, in APPKINL-G-F mice showing Aß42 elevation, the increased phosphorylation of IRS1 at multiple Ser sites occurs without memory impairment. Our findings suggest that the phosphorylation of IRS1 at specific Ser sites is a potential marker of Aß-unrelated memory deficits caused by type 2 diabetes and aging; however, in Aß-related memory decline, the modifications of IRS1 may be a marker of early detection of Aß42 elevation prior to the onset of memory decline in AD.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Insulina/metabolismo , Transtornos da Memória/metabolismo , Memória , Envelhecimento , Doença de Alzheimer/complicações , Animais , Encéfalo/metabolismo , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Masculino , Transtornos da Memória/etiologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosforilação , Serina/metabolismo , Transdução de Sinais
13.
Mol Cells ; 42(8): 604-616, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31446747

RESUMO

Phosphoserine phosphatase (PSPH) is one of the key enzymes of the L-serine synthesis pathway. PSPH is reported to affect the progression and survival of several cancers in an L-serine synthesis-independent manner, but the mechanism remains elusive. We demonstrate that PSPH promotes lung cancer progression through a noncanonical L-serine-independent pathway. PSPH was significantly associated with the prognosis of lung cancer patients and regulated the invasion and colony formation of lung cancer cells. Interestingly, L-serine had no effect on the altered invasion and colony formation by PSPH. Upon measuring the phosphatase activity of PSPH on a serine-phosphorylated peptide, we found that PSPH dephosphorylated phospho-serine in peptide sequences. To identify the target proteins of PSPH, we analyzed the protein phosphorylation profile and the PSPH-interacting protein profile using proteomic analyses and found one putative target protein, IRS-1. Immunoprecipitation and immunoblot assays validated a specific interaction between PSPH and IRS1 and the dephosphorylation of phospho-IRS-1 by PSPH in lung cancer cells. We suggest that the specific interaction and dephosphorylation activity of PSPH have novel therapeutic potential for lung cancer treatment, while the metabolic activity of PSPH, as a therapeutic target, is controversial.


Assuntos
Progressão da Doença , Proteínas Substratos do Receptor de Insulina/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Monoéster Fosfórico Hidrolases/metabolismo , Serina/metabolismo , Células A549 , Animais , Humanos , Camundongos , Invasividade Neoplásica , Fosforilação , Transdução de Sinais , Análise de Sobrevida , Ensaio Tumoral de Célula-Tronco
14.
Mol Cell Biochem ; 461(1-2): 65-72, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31327095

RESUMO

Azoramide is identified as a new compound with the dual properties for the improvement of ER-folding capacity in various cells as well as for the treatment of T2DM. Although the effect of azoramide in glucose-homeostasis in mammalians is not known very well, a limited number of experimental studies showed that it could improve the insulin sensitivity in genetically obese mice. Therefore, here, we aimed to investigate the direct effect of azoramide on insulin signaling in insulin-resistant (IR) cardiomyocytes using IR-modelled ventricular cardiomyocytes. This model was established in H9c2 cells using palmitic acid incubation (50-µM for 24-h). The development of IR in cells was verified by monitoring the cellular 2-DG6P uptake assays in these treated cells. The 2-DG6P uptake was 50% less in the IR-cells compared to the control cells, while azoramide treatment (20-µM for 48-h) could prevent fully that decrease. In addition, azoramide treatment markedly preserved the IR-induced less ATP production and high-ROS production in these IR-cells. Furthermore, this treatment prevented the functional changes in mitochondria characterized by depolarized mitochondrial membrane potential and mitochondrial fusion or fusion-related protein levels as well as cellular ATP level. Moreover, this treatment provided marked protection against IR-associated changes in the insulin signaling pathway in cells, including recovery in the phosphorylation of IRS1 and Akt as well as the protein level of GLUT4 and Akt. Our present results, for the first time, demonstrated that azoramide plays an important protective role in IR-cardiomyocytes, at most, protective action on mitochondria. Therefore, one can suggest that azoramide, as a novel regulator, can provide direct cardioprotection in the IR-heart, at most, via affecting mitochondria and can be a good candidate as a new drug for the treatment of IR-associated cardiovascular disorders in mammalians with systemic IR.


Assuntos
Amidas/farmacologia , Resistência à Insulina , Mitocôndrias/metabolismo , Ácido Palmítico/toxicidade , Tiazóis/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Glucose/metabolismo , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Ratos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
15.
J Agric Food Chem ; 67(30): 8348-8360, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31304751

RESUMO

We have recently demonstrated that tau hyperphosphorylation causes diabetic synaptic neurodegeneration of retinal ganglion cells (RGCs), which might be the earliest affair during the pathogenesis of diabetic retinopathy (DR). Thus, there is a pressing need to seek therapeutic agents possessing neuroprotective effects against tau hyperphosphorylation in RGCs for arresting the progression of DR. Here, using a well-characterized diabetes model of db/db mouse, we discovered that topical ocular application of 10 mg/kg/day of ginsenoside Rg1 (GRg1), one of the major active ingredients extracted from Panax ginseng and Panax notoginseng, ameliorated hyperphosphorylated tau-triggered RGCs synaptic neurodegeneration in diabetic mice. The neuroprotective effects of GRg1 on diabetic retinae were abrogated when retinal IRS-1 or Akt was suppressed by intravitreal injection with si-IRS-1 or topically coadministered with a specific inhibitor of Akt, respectively. However, selective repression of retinal GSK3ß by intravitreal administration of si-GSK3ß rescued the neuroprotective properties of GRg1 when Akt was inactivated. Therefore, the present study showed for the first time that GRg1 can prevent hyperphosphorylated tau-induced synaptic neurodegeneration of RGCs via activation of IRS-1/Akt/GSK3ß signaling in the early phase of DR. Moreover, our data clarify the potential therapeutic significance of GRg1 for neuroprotective intervention strategies of DR.


Assuntos
Retinopatia Diabética/tratamento farmacológico , Ginsenosídeos/administração & dosagem , Glicogênio Sintase Quinase 3 beta/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Fármacos Neuroprotetores/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Ganglionares da Retina/efeitos dos fármacos , Proteínas tau/metabolismo , Animais , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Glicogênio Sintase Quinase 3 beta/genética , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Degeneração Neural/tratamento farmacológico , Degeneração Neural/genética , Degeneração Neural/metabolismo , Panax notoginseng/química , Fosforilação , Extratos Vegetais/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/genética , Retina/patologia , Células Ganglionares da Retina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas tau/genética
16.
BMC Complement Altern Med ; 19(1): 136, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215434

RESUMO

BACKGROUND: Tomato fruit (Lycopersicon esculentum Mill.) has been suggested to be useful for the prevention of diabetes. Esculeoside A is the main saponin compounds in tomatoes. This study investigated the hypoglycemic effects and the underlying mechanism of esculeoside A in C57BLKS/Leprdb (db/db) mice. METHODS: Wild-type C57BLKS (db/dm) mice were used in the db/dm mouse group and db/db mice were randomly divided into 2 groups: untreated and treated db/db mouse groups. Esculeoside A (100 mg/kg) was administered by gavage for 56 days to the treated db/db mouse group. Distilled water was administered to the db/dm mouse group and the untreated db/db mouse group. The blood and liver biochemical parameters and the expression of liver insulin signaling-related proteins were examined. RESULTS: The results showed that esculeoside A reduced the fasting blood glucose (FBG) levels and improved the glucose tolerance. Further investigation revealed that hepatic protein expressions of total AMP-activated protein kinase (T-AMPK), phosphorylated AMP-activated protein kinase (p-AMPK), insulin receptor substrate-1 (IRS-1), and glucokinase (GCK) were significantly upregulated after esculeoside A treatment. In contrast, the hepatic protein expression of phosphoenolpyruvate carboxykinase (PEPCK) was significantly downregulated by esculeoside A treatment. CONCLUSION: These findings suggested that esculeoside A has a potential of alleviating the metabolic abnormalities in db/db mice via regulation of AMPK/IRS-1 pathway. Our findings supported a possible application of esculeoside A as a functional supplement for diabetes treatment.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Proteínas Substratos do Receptor de Insulina/genética , Sapogeninas/administração & dosagem , Proteínas Quinases Ativadas por AMP/genética , Animais , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Glucoquinase/genética , Glucoquinase/metabolismo , Humanos , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Regulação para Cima
17.
J Ethnopharmacol ; 241: 112009, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31158442

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Agriophyllum squarrosum (L.) Moq. is a traditional Mongol medicine commonly used in the treatment of diabetes. AIM OF THE STUDY: To examine the effects of Agriophyllum squarrosum extract (ASE) on glucose metabolism in type 2 diabetic KKAy mice, and to investigate the mechanisms underlying these effects. MATERIAL AND METHODS: KKAy mice were divided into a model control group (MCG), a low-dose Agriophyllum squarrosum extract group (LASEG), a medium-dose Agriophyllum squarrosum extract group (MASEG), a high-dose Agriophyllum squarrosum extract group (HASEG), and a metformin group (MEG). Syngeneic C57BL/6 mice were used as a normal control group (NCG). Drugs were administered to all mice by gavage for 8 weeks. Random blood glucose levels were measured in the mice at baseline and after 2, 4, and 8 weeks of treatment. Glucose tolerance was measured after 6 weeks of drug administration. After 8 weeks, glycated serum proteins (GSP) and advanced glycation end-products (AGEs) in the serum of all mice were measured. Sections of mouse liver tissues were used for periodic acid-Schiff staining (PAS) and the content of hepatic glycogen was determined. Immunohistochemistry was used to determine the effects of ASE on liver phospho-insulin receptor substrate 2 (P-IRS2) protein expression. Western blotting was used to quantify the protein expression levels of phosphatidylinositol 3-kinase (PI3K), AKT, phospho-AKT (S473) (P-AKT), glycogen synthase kinase 3ß (GSK3ß), and glucose transporters 4 (GLUT4), while PCR was used to quantify the mRNA expression levels of insulin receptor substrate 2 (IRS2), PI3K, AKT, GSK3ß, and GLUT4. RESULTS: ASE treatment decreased random blood glucose levels in type 2 diabetic KKAy mice; increased glucose tolerance; decreased serum GSP and AGEs content; increased glycogen synthesis in liver tissues; upregulated the protein expression levels of PI3K, AKT, GLUT4, and P-IRS2; downregulated the protein expression level of GSK3ß in liver tissues; upregulated the mRNA expression levels of IRS2, PI3K, AKT, and GLUT4; and downregulated the mRNA expression level of GSK3ß in liver tissues. CONCLUSION: ASE treatment may increase glucose metabolism in KKAy mice and improve glucose tolerance. The underlying mechanisms of the beneficial effects of ASE may be associated with the increase of glycogen synthesis, the inhibition of AGEs production, the upregulation of IRS2, PI3K, AKT, and GLUT4 protein and mRNA expression, and the downregulation of GSK3ß protein and mRNA expression.


Assuntos
Chenopodiaceae , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Obesidade/metabolismo , Extratos Vegetais/farmacologia , Animais , Proteínas Sanguíneas/análise , Diabetes Mellitus Experimental/sangue , Modelos Animais de Doenças , Feminino , Produtos Finais de Glicação Avançada/sangue , Glicogênio/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Obesidade/sangue , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
18.
Molecules ; 24(9)2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31035366

RESUMO

Limonoids are phytochemicals with a variety of biological properties. In the present study, we elucidated the molecular mechanism of suppression of adipogenesis in adipocytes by a limonoid, 7-deacetoxy-7-oxogedunin (CG-1) from Carapa guianensis (Meliaceae), known as andiroba. CG-1 reduced the accumulation of intracellular triglycerides in a concentration-dependent manner. The expression levels of the adipogenic, lipogenic, and lipolytic genes were decreased by CG-1 treatment, whereas the glycerol release level was not affected. When CG-1 was added into the medium during days 0-2 of 6-days-adipogenesis, the accumulation of intracellular lipids and the mRNA levels of the adipogenesis-related genes were decreased. In addition, the phosphorylation level of insulin receptor substrate-1 (IRS-1) and Akt in the early phase of adipocyte differentiation (within 1 day after initiating adipocyte differentiation) was reduced by CG-1. Furthermore, insulin-activated translocation of glucose transporter 4 to the plasma membranes in adipocytes was suppressed by CG-1, followed by decreased glucose uptake into the cells. These results indicate that an andiroba limonoid CG-1 suppressed the accumulation of intracellular lipids in the early phase of adipocyte differentiation through repression of IRS-1/Akt-mediated glucose uptake in adipocytes.


Assuntos
Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Transportador de Glucose Tipo 4/genética , Glucose/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Limoninas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células 3T3-L1 , Adipogenia/efeitos dos fármacos , Animais , Transportador de Glucose Tipo 4/metabolismo , Limoninas/química , Meliaceae/química , Camundongos , Estrutura Molecular
19.
Phytother Res ; 33(6): 1697-1705, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31074547

RESUMO

The aim of this study was to evaluate the effect and mechanism of hesperidin (HES) on insulin resistance (IR) in the human hepatocellular carcinoma cell line (HepG2 cells). HepG2 cells were induced with lipopolysaccharide (LPS) as a model of IR and treated with HES at three dosages. Next, the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), the glucose content, and glucose uptake were evaluated by enzyme-linked immunosorbent assay, glucose oxidase-peroxidase method (GOD-POD), or (2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl)amino)-2-deoxyglucose) (2-NBDG). Moreover, the protein expression of toll-like receptors 4 (TLR4), insulin receptor substrate 1 (IRS1), nuclear factor kappa B (NF-κB), and glucose transporter 2 (GLUT2) in HepG2 cells treated with HES were assessed via western blotting analysis. In addition, GLUT2 protein expression exposed to HES was detected following treatment with TLR4 inhibitor (HTA125). Our results demonstrated that HES decreased the levels of TNF-α and IL-6, attenuated the glucose content in culture medium and increased glucose uptake in insulin-resistant HepG2 cells in vitro. Moreover, HES upregulated the expression of IRS1 and GLUT2 protein and downregulated the protein expression of TLR4 and NF-κB in insulin-resistant HepG2 cells. The expression of GLUT2 protein had no significant changes when treated with HES after blockade of TLR4. HES attenuated IR in LPS-inducedinsulin-resistant HepG2 cells. Therefore, regulating the IRS1-GLUT2 pathway via TLR4 represents a potential mechanism of HES on IR in HepG2 cells.


Assuntos
Transportador de Glucose Tipo 2/metabolismo , Hesperidina/farmacologia , Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina , Receptor 4 Toll-Like/metabolismo , Animais , Glucose/metabolismo , Células Hep G2 , Humanos , Insulina/metabolismo , Resistência à Insulina/fisiologia , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
20.
Cells ; 8(5)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31052442

RESUMO

Glucocorticoids represent some of the most prescribed drugs that are widely used in the treatment of neuromuscular diseases, but their usage leads to side effects such as muscle atrophy. However, different synthetic glucocorticoids can lead to different muscle effects, depending upon its chemical formulation. Here, we intended to demonstrate the muscle histologic and molecular effects of administering different glucocorticoids in equivalency and different dosages. Methods: Seventy male Wistar rats distributed into seven groups received different glucocorticoids in equivalency for ten days or saline solution. The study groups were: Control group (CT) saline solution; dexamethasone (DX) 1.25 or 2.5 mg/kg/day; methylprednisolone (MP) 6.7 or 13.3mg/kg/day; and deflazacort (DC) 10 or 20 mg/kg/day. At the end of the study, the animals were euthanized, and the tibialis anterior and gastrocnemius muscles were collected for metachromatic ATPase (Cross-sectional area (CSA) measurement), Western blotting (protein expression of IGF-1 and Ras/Raf/MEK/ERK pathways) and RT-PCR (MYOSTATIN, MuRF-1, Atrogin-1, REDD-1, REDD-2, MYOD, MYOG and IRS1/2 genes expression) experiments. Results: Muscle atrophy occurred preferentially in type 2B fibers in all glucocorticoid treated groups. DC on 10 mg/kg/day was less harmful to type 2B fibers CSA than other doses and types of synthetic glucocorticoids. In type 1 fibers CSA, lower doses of DC and DX were more harmful than high doses. DX had a greater effect on the IGF-1 pathway than other glucocorticoids. MP more significantly affected P-ERK1/2 expression, muscle fiber switching (fast-to-slow), and expression of REDD1 and MyoD genes than other glucocorticoids. Compared to DX and MP, DC had less of an effect on the expression of atrogenes (MURF-1 and Atrogin-1) despite increased MYOSTATIN and decreased IRS-2 genes expression. Conclusions: Different glucocorticoids appears to cause muscle atrophy affecting secondarily different signaling mechanisms. MP is more likely to affect body/muscles mass, MEK/ERK pathway and fiber type transition, DX the IGF-1 pathway and IRS1/2 expression. DC had the smallest effect on muscle atrophic response possibly due a delayed timing on atrogenes response.


Assuntos
Dexametasona/farmacologia , Metilprednisolona/farmacologia , Músculo Esquelético/efeitos dos fármacos , Pregnenodionas/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Dexametasona/administração & dosagem , Regulação da Expressão Gênica/efeitos dos fármacos , Glucocorticoides/administração & dosagem , Glucocorticoides/farmacologia , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/metabolismo , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Metilprednisolona/administração & dosagem , Desenvolvimento Muscular/efeitos dos fármacos , Desenvolvimento Muscular/genética , Fibras Musculares Esqueléticas/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Pregnenodionas/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA