RESUMO
Naproxen is widely used for anti-inflammatory treatment but it can lead to serious side effects. To improve the anti-inflammatory activity and safety, a novel naproxen derivative containing cinnamic acid (NDC) was synthesized and used in combination with resveratrol. The results showed that the combination of NDC and resveratrol at different ratios have a synergistic anti-inflammatory efficacy in RAW264.7 macrophage cells. It was indicated that the combination of NDC and resveratrol at a ratio of 2:1 significantly inhibited the expression of carbon monoxide (NO), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), induced nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) and reactive oxygen species (ROS) without detectable side effects on cell viability. Further studies revealed that these anti-inflammatory effects were mediated by the activation of nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK) and phosphoinositide-3 kinase (PI3K)/protein kinase B (Akt) signaling pathways, respectively. Taken together, these results highlighted the synergistic NDC and resveratrol anti-inflammatory activity that could be further explored as a strategy for the treatment of inflammatory disease with an improved safety profile.
Assuntos
Proteínas Quinases Ativadas por Mitógeno , NF-kappa B , Animais , Camundongos , NF-kappa B/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Resveratrol/farmacologia , Naproxeno/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Transdução de Sinais , Anti-Inflamatórios/farmacologia , Células RAW 264.7 , Lipopolissacarídeos/farmacologia , Óxido Nítrico/metabolismo , Ciclo-Oxigenase 2/metabolismoRESUMO
Promoting energy expenditure is known to curb obesity and can be exploited for its treatment. Our previous study has demonstrated that activation of HSF1/PGC-1α axis efficiently induced mitochondrial biogenesis and adaptive oxidation and thus ameliorating lipid accumulation, however, whether it can be a therapeutic approach for metabolic disorders treatment needs explored. Here, a high-efficient and specific HSF1/PGC-1α activator screening system was established and the natural clinical liver-protecting agent matrine was identified as a robust HSF1/PGC-1α activator. Matrine treatment efficiently induced mitogenesis and thermogenic program in primary mouse adipose stem cell derived adipocytes by enriching HSF1 to the promoter of Pgc-1α. Deficiency of PGC-1α in adipocytes diminished the browning induction ability of matrine. Oral administration of matrine to the obese mice induced by high fat and high cholesterol diet increased energy expenditure and corrected the degeneration of thermogenesis in brown adipose tissue (BAT). Also, matrine treatment markedly induced the transformation of brown-like adipocytes in subcutaneous white adipose tissue (sWAT) via a mechanism of HSF1/PGC-1α, thereby attenuating obesity and myriads of metabolic disorders. This led to an improvement in adaptive thermogenesis to cold stimuli. These findings are of great significance in understanding the regulation mechanisms of the HSF1/PGC-1α axis in thermogenesis and providing a novel therapeutic approach for obesity treatment. Matrine may have potential therapeutic implications for the treatment of obesity in clinics.
Assuntos
Tecido Adiposo Marrom , Termogênese , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Alcaloides , Animais , Metabolismo Energético , Fatores de Transcrição de Choque Térmico/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Quinolizinas , MatrinasRESUMO
Metabolic-associated fatty liver disease (MAFLD) is the most common metabolic disease with a global prevalence of 25%. While MAFLD is serious and incurable at the later stage, it can be controlled or reversed at the early stage of hepatosteatosis originating from unhealthy diets. Recent laboratory evidence implicates a critical role of the mammalian target of rapamycin (mTOR)-autophagy signaling pathway in the pathogenesis of MAFLD induced by a high-fructose diet mimicking the overconsumption of sugar in humans. This review discusses the possible molecular mechanisms of mTOR-autophagy-endoplasmic reticulum (ER) stress in MAFLD. Based on careful analysis of recent studies, we suggest possible new therapeutic concepts or targets that can be explored for the discovery of new anti-MAFLD drugs.
Assuntos
Autofagia , Frutose/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Estresse do Retículo Endoplasmático , Frutose/efeitos adversos , Humanos , Transdução de SinaisRESUMO
Consumption of diet rich in fat and cigarette smoking (CS) are independent risk factors of non-alcoholic steatohepatitis (NASH), and they often occur together in some populations. The present study investigated the mechanisms of high-fat diet (HFD) and CS, individually and in combination, on the pathogenesis of NASH in mice. C57BL/6 male mice were subjected to either a low-fat chow (CH) or HFD with or without mainstream CS-exposure (4 cigarettes/day, 5 days/ week for 14 weeks). HFD alone caused hepatosteatosis (2.5-fold increase in TG content) and a significant increase in 3-nitrotyrisine (by â¼40-fold) but without an indication of liver injury, inflammation or fibrosis. CS alone in CH-fed mice increased in Tnfα expression and macrophage infiltration by 2-fold and relatively less increase in 3-nitrotyrosine (18-fold). Combination of HFD and CS precipitated hepatosteatosis to NASH reflected by exacerbated makers of liver inflammation and fibrosis which were associated with much severe liver oxidative stress (90-fold increase in 3-nitrotyrisine along with 6-fold increase in carbonylated proteins and 56% increase in lipid oxidations). Further studies were performed to administer the antioxidant tempol to CS exposed HFD mice and the results showed that the inhibition of liver oxidative stress prevented inflammatory and fibrotic changes in liver despite persisting hepatosteatosis. Our findings suggest that oxidative stress is a key mechanism underlying CS-promoted progression of simple hepatosteatosis to NASH. Targeting hepatic oxidative stress may be a viable strategy in halting the progression of metabolic associated fatty liver disease.
Assuntos
Cirrose Hepática/etiologia , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Estresse Oxidativo , Poluição por Fumaça de Tabaco/efeitos adversos , Animais , Antioxidantes/farmacologia , Óxidos N-Cíclicos/farmacologia , Dieta Hiperlipídica , Modelos Animais de Doenças , Progressão da Doença , Interleucina-1beta/metabolismo , Peroxidação de Lipídeos , Fígado/efeitos dos fármacos , Fígado/patologia , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Cirrose Hepática/prevenção & controle , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Estresse Oxidativo/efeitos dos fármacos , Carbonilação Proteica , Marcadores de Spin , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Cigarette smoking (CS) is known to reduce body weight and this often masks its real effect on insulin action. The present study tested the hypothesis that CS can divert lipid deposition to muscles to offset the supposed benefit of reduced body weight gain on insulin signalling in this major site for glucose tolerance (or insulin action). The study was conducted in mice exposed to chronic CS followed by either a chow (CH) diet or a high-fat (HF) diet. CS increased triglyceride (TG) levels in both plasma and muscle despite a reduced body weight gain and adiposity. CS led to glucose intolerance in CH-fed mice and they retained the glucose intolerance that was induced by the HF diet. In adipose tissue, CS increased macrophage infiltration and the mRNA expression of TNFα but suppressed the protein expression of adipose triglyceride lipase and PPARγ. While CS increased hormone-sensitive lipase and suppressed the mRNA expression of leptin, these effects were blunted in HF-fed mice. These results imply that CS impairs insulin signalling in skeletal muscle via accumulated intramuscular lipids from lipolysis and lipodystrophy of adipose tissues. This may explain why smokers may not benefit from insulin sensitising effects of reduced body weight gain.
Assuntos
Fumar Cigarros/efeitos adversos , Insulina/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Músculo Esquelético/metabolismo , Obesidade/metabolismo , Aumento de Peso/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Fumar Cigarros/genética , Fumar Cigarros/metabolismo , Fumar Cigarros/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Glucose/metabolismo , Humanos , Lipólise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/genética , Obesidade/fisiopatologia , PPAR gama/genética , PPAR gama/metabolismo , Triglicerídeos/metabolismoRESUMO
Chronic Obstructive Pulmonary Disease (COPD) is a major incurable global health burden and will become the third largest cause of death in the world by 2030. It is well established that an exaggerated inflammatory and oxidative stress response to cigarette smoke (CS) leads to, emphysema, small airway fibrosis, mucus hypersecretion, and progressive airflow limitation. Current treatments have limited efficacy in inhibiting chronic inflammation and consequently do not reverse the pathology that initiates and drives the long-term progression of disease. In particular, there are no effective therapeutics that target neutrophilic inflammation in COPD, which is known to cause tissue damage by degranulation of a suite of proteolytic enzymes including neutrophil elastase (NE). Matrine, an alkaloid compound extracted from Sophora flavescens Ait, has well known anti-inflammatory activity. Therefore, the aim of the present study was to investigate whether matrine could inhibit CS-induced lung inflammation in mice. Matrine significantly reduced CS-induced bronchoalveolar lavage fluid (BALF) neutrophilia and NE activity in mice. The reduction in BALF neutrophils in CS-exposed mice by matrine was not due to reductions in pro-neutrophil cytokines/chemokines, but rather matrine's ability to cause apoptosis of neutrophils, which we demonstrated ex vivo Thus, our data suggest that matrine has anti-inflammatory actions that could be of therapeutic potential in treating CS-induced lung inflammation observed in COPD.
Assuntos
Alcaloides/farmacologia , Anti-Inflamatórios/farmacologia , Apoptose/efeitos dos fármacos , Fumar Cigarros , Lesão Pulmonar/prevenção & controle , Pulmão/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Quinolizinas/farmacologia , Animais , Células Cultivadas , Citocinas/metabolismo , Modelos Animais de Doenças , Elastase de Leucócito/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Pulmão/patologia , Lesão Pulmonar/imunologia , Lesão Pulmonar/metabolismo , Lesão Pulmonar/patologia , Masculino , Camundongos Endogâmicos BALB C , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/patologia , Peroxidase/metabolismo , Fumaça , MatrinasRESUMO
Gluconeogenesis is a major source of hyperglycemia in patients with type 2 diabetes mellitus (T2DM), thus targeting gluconeogenesis to suppress glucose production is a promising strategy for anti-T2DM drug discovery. In our preliminary in vitro studies, we found that a small-molecule (E)-3-(2-(quinoline-4-yl)vinyl)-1H-indol-6-ol (QVO) inhibited the hepatic glucose production (HGP) in primary hepatocytes. We further revealed that QVO suppressed hepatic gluconeogenesis involving calmodulin-dependent protein kinase kinase ß- and liver kinase B1-adenosine monophosphate-activated protein kinase (AMPK) pathways as well as AMPK-independent mitochondrial function-related signaling pathway. To evaluate QVO's anti-T2DM activity in vivo, which was impeded by the complicated synthesis route of QVO with a low yield, we designed and synthesized 4-[2-(1H-indol-3-yl)vinyl]quinoline (IVQ) as a prodrug with easier synthesis route and higher yield. IVQ did not inhibit the HGP in primary hepatocytes in vitro. Pharmacokinetic studies demonstrated that IVQ was quickly converted to QVO in mice and rats following administration. In both db/db and ob/ob mice, oral administration of IVQ hydrochloride (IVQ-HCl) (23 and 46 mg/kg every day, for 5 weeks) ameliorated hyperglycemia, and suppressed hepatic gluconeogenesis and activated AMPK signaling pathway in the liver tissues. Furthermore, IVQ caused neither cardiovascular system dysfunction nor genotoxicity. The good druggability of IVQ has highlighted its potential in the treatment of T2DM and the prodrug design for anti-T2DM drug development.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Gluconeogênese/efeitos dos fármacos , Hipoglicemiantes/uso terapêutico , Indóis/uso terapêutico , Pró-Fármacos/uso terapêutico , Quinolinas/uso terapêutico , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Diabetes Mellitus Experimental/tratamento farmacológico , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Ativadores de Enzimas/uso terapêutico , Ativadores de Enzimas/toxicidade , Inibidores Enzimáticos/uso terapêutico , Inibidores Enzimáticos/toxicidade , Glucose-6-Fosfatase/antagonistas & inibidores , Hepatócitos/efeitos dos fármacos , Hipoglicemiantes/toxicidade , Indóis/toxicidade , Fígado/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Fosfoenolpiruvato Carboxiquinase (GTP)/antagonistas & inibidores , Pró-Fármacos/toxicidade , Quinolinas/toxicidade , Transdução de Sinais/efeitos dos fármacosRESUMO
The pathogenesis of Alzheimer's disease (AD) is characterized by both accumulation of ß-amyloid (Aß) plaque and formation of neurofibrillary tangles in the brain. Recent evidence shows that autophagy activation may potently promote intracellular Aß clearance. Thus targeting autophagy becomes a promising strategy for discovery of drug leads against AD. In the present study, we established a platform to discover autophagy stimulator and screened the lab in-house FDA-approved drug library. We found that anti-parasitic drug nitazoxanide (NTZ) was an autophagy activator and could efficiently improve learning and memory impairments in APP/PS1 transgenic mice. In BV2 cells and primary cortical astrocytes, NTZ stimulated autophagy and promoted Aß clearance by inhibiting both PI3K/AKT/mTOR/ULK1 and NQO1/mTOR/ULK1 signaling pathways; NTZ treatment attenuated LPS-induced inflammation by inhibiting PI3K/AKT/IκB/NFκB signaling. In SH-SY5Y cells and primary cortical neurons, NTZ treatment restrained tau hyperphosphorylation through inhibition of PI3K/AKT/GSK3ß pathway. The beneficial effects and related signaling mechanisms from the in vitro studies were also observed in APP/PS1 transgenic mice following administration of NTZ (90 mg·kg-1·d-1, ig) for 100 days. Furthermore, NTZ administration decreased Aß level and senile plaque formation in the hippocampus and cerebral cortex of APP/PS1 transgenic mice, and improved learning and memory impairments in Morris water maze assay. In conclusion, our results highlight the potential of NTZ in the treatment of AD.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Antiparasitários/farmacologia , Modelos Animais de Doenças , Aprendizagem/efeitos dos fármacos , Transtornos da Memória/tratamento farmacológico , Tiazóis/farmacologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Células Cultivadas , Humanos , Transtornos da Memória/metabolismo , Camundongos , NitrocompostosRESUMO
The present study investigated the efficacy of the hepatoprotective drug matrine (Mtr) for its new application for hepatosteatosis and associated disorders in glucose homeostasis. The study was performed in two nutritional models of hepatosteatosis in mice with various abnormal glucose homeostasis: (1) high-fructose diet (HFru) induced hepatosteatosis and glucose intolerance from hepatic, and (2) hepatosteatosis and hyperglycemia induced by high-fat (HF) diet in combination with low doses of streptozotocin (STZ). Administration of Mtr (100 mg/kg every day in diet for 4 weeks) abolished HFru-induced hepatosteatosis and glucose intolerance. These effects were associated with the inhibition of HFru-stimulated de novo lipogenesis (DNL) without altering hepatic fatty acid oxidation. Further investigation revealed that HFru-induced endoplasmic reticulum (ER) stress was inhibited, whereas heat-shock protein 72 (an inducible chaperon protein) was increased by Mtr. In a type 2 diabetic model induced by HF-STZ, Mtr reduced hepatosteatosis and improved attenuated hyperglycemia. The hepatoprotective drug Mtr may be repurposed for the treatment of hepatosteatosis and associated disorders in glucose homeostasis. The inhibition of ER stress associated DNL and fatty acid influx appears to play an important role in these metabolic effects.
Assuntos
Alcaloides/uso terapêutico , Reposicionamento de Medicamentos , Fígado Gorduroso/tratamento farmacológico , Intolerância à Glucose/tratamento farmacológico , Substâncias Protetoras/uso terapêutico , Quinolizinas/uso terapêutico , Adiposidade/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Ácidos Graxos/metabolismo , Frutose/efeitos adversos , Frutose/metabolismo , Proteínas de Choque Térmico HSP72/metabolismo , Homeostase/efeitos dos fármacos , Lipogênese/efeitos dos fármacos , Fígado/fisiopatologia , Camundongos Endogâmicos C57BL , Triglicerídeos/metabolismo , MatrinasRESUMO
The accumulation of unfolded proteins within the endoplasmic reticulum (ER) causes ER stress and activation of unfolded protein response (UPR). This response can trigger ER-associated degradation and autophagy, which clear unfolded proteins and restore protein homeostasis. Recently, it has become clear that ubiquitination plays an important role in the regulation of autophagy. In the present study, we investigated how the E3 ubiquitin ligase neural precursor cell-expressed, developmentally down-regulated protein 4-2 (Nedd4-2) interacts with ER stress and autophagy. In mice, we found that an increase in the expression of Nedd4-2, which was concomitant with the activation of the UPR and autophagy, was caused by a prolonged high-fructose and high-fat diet that induces ER stress in the liver. Pharmacologic induction of ER stress also led to an increase in Nedd4-2 expression in cultured cells, which was coincident with UPR and autophagy activation. The inhibition of inositol-requiring enzyme 1 significantly suppressed Nedd4-2 expression. Moreover, increased Nedd4-2 expression in vivo was closely associated with the activation of inositol-requiring enzyme 1 and increased expression of the spliced form of X-box binding protein 1. Furthermore, knockdown of Nedd4-2 in cultured cells suppressed both basal autophagy and ER stress-induced autophagy, whereas overexpression of Nedd4-2-induced autophagy. Taken together, our findings provide evidence that Nedd4-2 is up-regulated in response to ER stress by the spliced form of X-box binding protein 1 and that this is important in the induction of an appropriate autophagic response.-Wang, H. Sun, R.-Q., Camera, D., Zeng, X.-Y., Jo, E., Chan, S. M. H., Herbert, T. P., Molero, J. C., Ye, J.-M. Endoplasmic reticulum stress up-regulates Nedd4-2 to induce autophagy.
Assuntos
Autofagia/fisiologia , Retículo Endoplasmático/fisiologia , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Regulação da Expressão Gênica/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Regulação para Cima/fisiologia , Animais , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Fibroblastos/metabolismo , Células HEK293 , Células HeLa , Humanos , Fígado/metabolismo , Masculino , Camundongos , Ubiquitina-Proteína Ligases Nedd4 , Ubiquitina-Proteína Ligases/genética , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismoRESUMO
Dipeptidyl peptidase IV (DPP-IV) is a promising Type 2 diabetes mellitus (T2DM) drug target. DPP-IV inhibitors prolong the action of glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), improve glucose homeostasis without weight gain, edema, and hypoglycemia. However, the marketed DPP-IV inhibitors have adverse effects such as nasopharyngitis, headache, nausea, hypersensitivity, skin reactions and pancreatitis. Therefore, it is still expected for novel DPP-IV inhibitors with minimal adverse effects. The scaffolds of existing DPP-IV inhibitors are structurally diversified. This makes it difficult to build virtual screening models based upon the known DPP-IV inhibitor libraries using conventional QSAR approaches. In this paper, we report a new strategy to predict DPP-IV inhibitors with machine learning approaches involving naïve Bayesian (NB) and recursive partitioning (RP) methods. We built 247 machine learning models based on 1307 known DPP-IV inhibitors with optimized molecular properties and topological fingerprints as descriptors. The overall predictive accuracies of the optimized models were greater than 80%. An external test set, composed of 65 recently reported compounds, was employed to validate the optimized models. The results demonstrated that both NB and RP models have a good predictive ability based on different combinations of descriptors. Twenty "good" and twenty "bad" structural fragments for DPP-IV inhibitors can also be derived from these models for inspiring the new DPP-IV inhibitor scaffold design.
Assuntos
Desenho Assistido por Computador , Inibidores da Dipeptidil Peptidase IV/química , Inibidores da Dipeptidil Peptidase IV/farmacologia , Desenho de Fármacos , Aprendizado de Máquina , Teorema de Bayes , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dipeptidil Peptidase 4/química , Dipeptidil Peptidase 4/metabolismo , Humanos , Simulação de Acoplamento Molecular , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
Hepatic steatosis is often associated with insulin resistance as a hallmark of the metabolic syndrome in the liver. The present study investigated the effects of PPARα activation induced by fenofibrate (FB) on the relationship of insulin resistance and hepatic steatosis in mice fed a high-fat (HF) diet, which increases lipid influx into the liver. Mice were fed HF diet to induce insulin resistance and hepatic steatosis with or without FB. FB activated PPARα and ameliorated HF diet-induced glucose intolerance and hepatic insulin resistance without altering either hepatic steatosis or inflammation signaling (JNK or IKK). Interestingly, FB treatment simultaneously increased fatty acid (FA) synthesis (50%) and oxidation (66%, both p<0.01) into intermediate lipid metabolites, suggesting a FA oxidation-synthesis cycling in operation. Associated with these effects, diacylglycerols (DAGs) were sequestered within the lipid droplet/ER compartment, thus reducing their deposition in the cellular membrane, which is known to impair insulin signal transduction. These findings suggest that the reduction in membrane DAGs (rather than total hepatic steatosis) may be critical for the protection by fenofibrate-induced PPARα activation against hepatic insulin resistance induced by dietary fat.
Assuntos
Diglicerídeos/metabolismo , Retículo Endoplasmático/metabolismo , Fígado Gorduroso/metabolismo , Fenofibrato/farmacologia , Hipolipemiantes/farmacologia , Insulina/metabolismo , Gotículas Lipídicas/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Retículo Endoplasmático/efeitos dos fármacos , Fígado Gorduroso/etiologia , Gotículas Lipídicas/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , PPAR alfa/metabolismo , Transdução de SinaisRESUMO
The unfolded protein response (UPR) pathways have been implicated in the development of hepatic insulin resistance during high fructose (HFru) feeding. The present study investigated their roles in initiating impaired insulin signaling transduction in the liver induced by HFru feeding in mice. HFru feeding resulted in hepatic steatosis, increased de novo lipogenesis and activation of two arms of the UPR pathways (IRE1/XBP1 and PERK/eIF2α) in similar patterns from 3days to 8weeks. In order to identify the earliest trigger of impaired insulin signaling in the liver, we fed mice a HFru diet for one day and revealed that only the IRE1 branch was activated (by 2-fold) and insulin-mediated Akt phosphorylation was blunted (~25%) in the liver. There were significant increases in phosphorylation of JNK (~50%) and IRS at serine site (~50%), protein content of ACC and FAS (up to 2.5-fold) and triglyceride level (2-fold) in liver (but not in muscle or fat). Blocking IRE1 activity abolished increases in JNK activity, IRS serine phosphorylation and protected insulin-stimulated Akt phosphorylation without altering hepatic steatosis or PKCε activity, a key link between lipids and insulin resistance. Our findings together suggest that activation of IRE1-JNK pathway is a key linker of impaired hepatic insulin signaling transduction induced by HFru feeding.
Assuntos
Frutose/administração & dosagem , Frutose/metabolismo , Insulina/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/fisiologia , Triglicerídeos/metabolismo , Animais , Resistência à Insulina , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Serina-Treonina Quinases/genética , Resposta a Proteínas não DobradasRESUMO
Glycogen is a vital highly branched polymer of glucose that is essential for blood glucose homeostasis. In this article, the structure of liver glycogen from mice is investigated with respect to size distributions, degradation kinetics, and branching structure, complemented by a comparison of normal and diabetic liver glycogen. This is done to screen for differences that may result from disease. Glycogen α-particle (diameter â¼ 150 nm) and ß-particle (diameter â¼ 25 nm) size distributions are reported, along with in vitro γ-amylase degradation experiments, and a small angle X-ray scattering analysis of mouse ß-particles. Type 2 diabetic liver glycogen upon extraction was found to be present as large loosely bound, aggregates, not present in normal livers. Liver glycogen was found to aggregate in vitro over a period of 20 h, and particle size is shown to be related to rate of glucose release, allowing a structure-function relationship to be inferred for the tissue specific distribution of particle types. Application of branching theories to small angle X-ray scattering data for mouse ß-particles revealed these particles to be randomly branched polymers, not fractal polymers. Together, this article shows that type 2 diabetic liver glycogen is present as large aggregates in mice, which may contribute to the inflexibility of interconversion between glucose and glycogen in type 2 diabetes, and further that glycogen particles are randomly branched with a size that is related to the rate of glucose release.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Glucose/metabolismo , Glicogênio/química , Fígado/metabolismo , Animais , Glicogênio/metabolismo , CamundongosRESUMO
Bouchardatine (1), a naturally occurring ß-indoloquinazoline alkaloid, was synthesized. For the first time, the lipid-lowering effect and mechanism of 1 was investigated in 3T3-L1 adipocytes. Our study showed that 1 could significantly reduce lipid accumulation without cytotoxicity and mainly inhibited early differentiation of adipocyte through proliferation inhibition and cell cycle arrested in dose-dependent manner. Furthermore, the inhibition of early differentiation was reflected by down-regulation of key regulators of adipogenesis/lipogenesis, including CCAAT enhancer binding proteins (C/EBPß, C/EBPδ, C/EBPα), peroxisome proliferator-activated receptors γ (PPARγ) and sterol-regulatory element binding protein-1c (SREBP-1c), in both of mRNA and protein levels. Subsequently decreasing the protein levels of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS), and stearyl coenzyme A desaturated enzyme 1 (SCD-1), the rate-limited metabolic enzymes of fatty acid synthesis, were also observed. Further studies revealed that 1 persistently activated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) during differentiation, suggesting that the AMPK may be an upstream mechanism for the effect of 1 on adipogenesis and lipogenesis. Our data suggest that 1 can be a candidate for the development of new therapeutic drugs against obesity and related metabolic disorders.
Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Fármacos Antiobesidade/química , Fármacos Antiobesidade/farmacologia , Alcaloides Indólicos/química , Lipogênese/efeitos dos fármacos , Células 3T3-L1 , Proteínas Quinases Ativadas por AMP/metabolismo , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Proteína alfa Estimuladora de Ligação a CCAAT/genética , Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Proteína delta de Ligação ao Facilitador CCAAT/genética , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Alcaloides Indólicos/farmacologia , Camundongos , PPAR gama/genética , PPAR gama/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismoRESUMO
Hepatic fibrosis is intricately associated with dysregulation of gut microbiota and host metabolomes. Our previous studies have demonstrated that matrine can effectively reduce hepatosteatosis and associated disorders. However, it is poorly understood whether the gut microbiota involved in the attenuation of liver fibrosis by matrine. Herein we explored a novel mechanism of how oral administration of matrine alleviates liver fibrosis by modulating gut microbiota. Administration of matrine not only potently ameliorated liver fibrosis in carbon tetrachloride (CCl4)-induced mice, but also significantly preserved hepatic heat shock protein 72 (HSP72) in vivo and in vitro. Matrine was failed to reduce liver fibrosis when HSP72 upregulation was blocked by the HSP72 antagonist VER-155008. Also, consumption of matrine significantly alleviated gut dysbiosis and fecal metabonomic changes in CCl4-treated mice. Transplanted the faces of matrine-treated mice induced a remarkable upregulation of HSP72 and remission of fibrosis in liver in CCl4-exposed mice and inhibition of TGF-ß1-induced inflammatory response and epithelial-mesenchymal transition (EMT) in AML-12 cells. Furthermore, deficiency of HSP72 partly reversed the intestinal microbial composition that prevented matrine from reducing CCl4-induced liver fibrosis in mice. This study reveals the "gut microbiota-hepatic HSP72" axis as a key mechanism of matrine in reducing liver fibrosis and suggest that this axis may be targeted for developing other new therapies for liver fibrosis.
RESUMO
Aldose reductase reduces glucose to sorbitol. It plays a key role in many of the complications arising from diabetes. Thus, aldose reductase inhibitors (ARI) have been identified as promising therapeutic agents for treating such complications of diabetes, as neuropathy, nephropathy, retinopathy, and cataracts. In this paper, a virtual screening protocol applied to a library of compounds in house has been utilized to discover novel ARIs. IC50's were determined for 15 hits that inhibited ALR2 to greater than 50% at 50 µM, and ten of these have an IC50 of 10 µM or less, corresponding to a rather substantial hit rate of 14% at this level. The specificity of these compounds relative to their cross-reactivity with human ALR1 was also assessed by inhibition assays. This resulted in identification of novel inhibitors with IC50's comparable to the commercially available drug, epalrestat, and greater than an order of magnitude better selectivity.
Assuntos
Aldeído Redutase/antagonistas & inibidores , Aldeído Redutase/química , Inibidores Enzimáticos/farmacologia , Interface Usuário-Computador , Sítios de Ligação , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Humanos , Modelos Moleculares , Simulação de Dinâmica Molecular , Conformação Proteica , Relação Estrutura-AtividadeRESUMO
This review discusses issues largely from the biological point of view about the targeted approaches for the use of natural products for the discovery of anti-diabetic drugs in collaboration with medicinal chemists and computer-aided drug design. A major thrust of this review reflects the collaborative research of four institutions: RMIT University (Australia), Garvan Institute of Medical Research (Australia), Shanghai Institute of Materia Medica of the Chinese Academy of Science (China) and Sun-Yat Sen University (China) in the past eight years. By joining forces of biomedical research in diabetes and medicinal chemistry with a focus on traditional medicine, they are trying to bridge the West (the latest research discoveries in biomedical research) with the East (traditional medicine) to step forward in drug discovery from natural products.
Assuntos
Produtos Biológicos/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Animais , Descoberta de Drogas , Humanos , Medicina Tradicional Chinesa , Resultado do TratamentoRESUMO
Diets() rich in fat are a major() cause() of metabolic disease(), and nutritional() food has been widely() used() to counteract the metabolic disorders such() as obesity() and fatty() liver(). The present study investigated the effects of oleuropein-enriched extract() from Jasminum grandiflorum L. flowers (OLE-JGF) in high-fat diet() (HFD)-fed mice and oleic acid() (OA)-treated AML-12 cells. Treatment() of HFD-fed mice with 0.6% OLE-JGF for 8 weeks significantly reduced body and liver() weights, as well as attenuating lipid dysmetabolism and hepatic steatosis. OLE-JGF administration() prominently suppressed the mRNA expressions() of monocyte chemoattractant protein()-1 (MCP-1) and cluster of differentiation 68 (CD68), and it also downregulated acetyl-CoA carboxylase (ACC) and fatty() acid() synthase (FAS) as well as sterol-regulatory-element()-binding protein() (SREBP-1c) in the liver(). Meanwhile, mitochondrial DNA and uncoupling protein() 2 (UCP2) were upregulated along with the increased expression() of mitochondrial biogenic promoters including liver() kinase B1 (LKB1), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear() factor()-erythroid-derived 2-like 2 (Nrf2), and mitochondrial transcription factor() A (Tfam), but did not change AMP-activated protein() kinase (AMPK) in liver(). The lipid droplets were decreased significantly after treatment() with 80 µM oleuropein for 24 h in OA-induced AML-12 cells. Furthermore, oleuropein significantly inhibited ACC mRNA expression() and upregulated LKB1, PGC-1α, and Tfam mRNA levels, as well as increasing the binding level of LKB1 to PGC-1α promoter in OA-induced cells. These findings indicate() that OLE-JGF reduces hepatic lipid deposition in HFD-fed mice, as well as the fact that OA-induced liver() cells may be partly() attributed to upregulation of the LKB1-PGC-1α axis, which mediates hepatic lipogenesis and mitochondrial biogenesis. Our study provides a scientific() basis() for the benefits and potential() use() of the J. grandiflorum flower as a food supplement() for the prevention() and treatment() of metabolic disease().
Assuntos
Carcinoma Hepatocelular , Fígado Gorduroso , Glucosídeos Iridoides , Jasminum , Leucemia Mieloide Aguda , Neoplasias Hepáticas , Doenças Metabólicas , Animais , Camundongos , Proteínas Serina-Treonina Quinases , Fígado Gorduroso/tratamento farmacológico , Proteínas Quinases Ativadas por AMP/genética , Acetil-CoA Carboxilase , RNA Mensageiro , Extratos Vegetais/farmacologia , LipídeosRESUMO
Human chemokine receptor CXCR3 (hCXCR3) antagonists have potential therapeutic applications as antivirus, antitumor, and anti-inflammatory agents. A novel virtual screening protocol, which combines pharmacophore-based and structure-based approaches, was proposed. A three-dimensional QSAR pharmacophore model and a structure-based docking model were built to virtually screen for hCXCR3 antagonists. The hCXCR3 antagonist binding site was constructed by homology modeling and molecular dynamics (MD) simulation. By combining the structure-based and ligand-based screenings results, 95% of the compounds satisfied either pharmacophore or docking score criteria and would be chosen as hits if the union of the two searches was taken. The false negative rates were 15% for the pharmacophore model, 14% for the homology model, and 5% for the combined model. Therefore, the consistency of the pharmacophore model and the structural binding model is 219/273 = 80%. The hit rate for the virtual screening protocol is 273/286 = 95%. This work demonstrated that the quality of both the pharmacophore model and homology model can be measured by the consistency of the two models, and the false negatives in virtual screening can be reduced by combining two virtual screening approaches.