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1.
PLoS One ; 15(9): e0236081, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32960890

RESUMO

Type 2 diabetes mellitus (T2DM), one of the most common metabolic diseases, is characterized by insulin resistance and inadequate insulin secretion of ß cells. Glycogen phosphorylase (GP) is the key enzyme in glycogen breakdown, and contributes to hepatic glucose production during fasting or during insulin resistance. Pharmacological GP inhibitors are potential glucose lowering agents, which may be used in T2DM therapy. A natural product isolated from the cultured broth of the fungal strain No. 138354, called 2,3-bis(4-hydroxycinnamoyloxy)glutaric acid (FR258900), was discovered a decade ago. In vivo studies showed that FR258900 significantly reduced blood glucose levels in diabetic mice. We previously showed that GP inhibitors can potently enhance the function of ß cells. The purpose of this study was to assess whether an analogue of FR258900 can influence ß cell function. BF142 (Meso-Dimethyl 2,3-bis[(E)-3-(4-acetoxyphenyl)prop-2-enamido]butanedioate) treatment activated the glucose-stimulated insulin secretion pathway, as indicated by enhanced glycolysis, increased mitochondrial oxidation, significantly increased ATP production, and elevated calcium influx in MIN6 cells. Furthermore, BF142 induced mTORC1-specific phosphorylation of S6K, increased levels of PDX1 and insulin protein, and increased insulin secretion. Our data suggest that BF142 can influence ß cell function and can support the insulin producing ability of ß cells.


Assuntos
Cinamatos/farmacologia , Inibidores Enzimáticos/farmacologia , Glutaratos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Ácido Succínico/farmacologia , Animais , Linhagem Celular Tumoral , Cinamatos/química , Inibidores Enzimáticos/química , Glucose/metabolismo , Glutaratos/química , Glicogênio Fosforilase/metabolismo , Glicólise/efeitos dos fármacos , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Metilação , Camundongos , Ácido Succínico/química
2.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R96-R105, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32459971

RESUMO

The rectal gland of the spiny dogfish Squalus acanthias secretes a salt solution isosmotic with plasma that maintains the salt homeostasis of the fish. It secretes salt against an electrochemical gradient that requires the expenditure of energy. Isolated rectal glands perfused without glucose secrete salt, albeit at a rate about 30% of glands perfused with 5 mM glucose. Gradually reducing the glucose concentration is associated with a progressive decrease in the secretion of chloride. The apparent Km for the exogenous glucose-dependent chloride secretion is around 2 mM. Phloretin and cytochalasin B, agents that inhibit facilitated glucose carriers of the solute carrier 2 (Slc2) family such as glucose transporter 2 (GLUT2), do not inhibit the secretion of chloride by the perfused rectal glands. Phloridzin, which inhibits Slc5 family of glucose symporters, or α-methyl-d-glucoside, which competitively inhibits the uptake of glucose through Slc5 symporters, inhibit the secretion of chloride. Thus the movement of glucose into the rectal gland cells appears to be mediated by a sodium-glucose symporter. Sodium-glucose cotransporter 1 (SGLT1), the first member of the Slc5 family of sodium-linked glucose symporters, was cloned from the rectal gland. No evidence of GLUT2 was found. The persistence of secretion of chloride in the absence of glucose in the perfusate suggests that there is an additional source of energy within the cells. The use of 2-mercapto-acetate did not result in any change in the secretion of chloride, suggesting that the oxidation of fatty acids is not the source of energy for the secretion of chloride. Perfusion of isolated glands with KCN in the absence of glucose further reduces the secretion of chloride but does not abolish it, again suggesting that there is another source of energy within the cells. Glucose was measured in the rectal gland cells and found to be at concentrations in the range of that in the perfusate. Glycogen measurements indicated that there are significant stores of glucose in the rectal gland. Moreover, glycogen synthase was partially cloned from rectal gland cells. The open reading frame of glycogen phosphorylase was also cloned from rectal gland cells. Measurements of glycogen phosphorylase showed that the enzyme is mostly in its active form in the cells. The cells of the rectal gland of the spiny dogfish require exogenous glucose to fully support the active secretion of salt. They have the means to transport glucose into the cells in the form of SGLT1. The cells also have an endogenous supply of glucose as glycogen and have the necessary elements to synthesize, store, and hydrolyze it.


Assuntos
Cloretos/metabolismo , Glucose/metabolismo , Glândula de Sal/metabolismo , Squalus/metabolismo , Animais , Sequência de Bases , Glucose/farmacologia , Transportador de Glucose Tipo 2/metabolismo , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Homeostase , Técnicas In Vitro , Cianeto de Potássio/farmacologia , Glândula de Sal/efeitos dos fármacos , Transportador 1 de Glucose-Sódio/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo II/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-31954198

RESUMO

This study investigated the effects of low salinity exposure on glycogen and its metabolism biomarkers, glycogen synthase (GS) and glycogen phosphorylase (GP), representing glycogen synthesis and catabolism, respectively, in the gills and liver of great blue-spotted mudskippers (Boleophthalmus pectinirostris). The fish were accumulated at 10‰ salinity seawater for 1 week, then 270 healthy great blue-spotted mudskippers with similar size were randomly transferred to 10‰ (control group) or 3‰ (low salinity group) seawater for 72-hour stress experiment. Fish significantly elevated their blood glucose levels 12 h after low salinity challenge. At the end of experiments, a decrease in liver glycogen contents was observed in both the control and low salinity groups, the latter showing a pronounced decrease, while the gill glycogen contents were not changed for either group. The mRNA abundance and enzyme activity of GS and GP were both elevated in gill tissues, showing a rising glycogen synthesis and catabolism, probably resulting in the unchanging gill glycogen content. While in liver tissues, the mRNA abundance and enzyme activity were decreased for GS and increased for GP, showing a net increase for breaking down glycogen in liver, probably for supplying a sufficient glucose level for gills and other tissues/organs involved in the response to salinity changes.


Assuntos
Peixes/metabolismo , Brânquias/metabolismo , Glicogênio/metabolismo , Fígado/metabolismo , Estresse Salino/fisiologia , Animais , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Salinidade
4.
Food Chem ; 314: 126203, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31978718

RESUMO

The activity, expression and S-nitrosylation of glycogen phosphorylase (GP), phosphofructokinase (PFK) and pyruvate kinase (PK) was compared between pale, soft and exudative (PSE) and red, firm and non-exudative (RFN) pork. The nitric oxide synthase (NOS) activity of RFN pork was higher than PSE pork (P < 0.05). Glycogen and lactic acid content were significantly different between PSE and RFN samples at 1 h postmortem (P < 0.05). Compared to PSE pork, RFN pork had lower activities and higher S-nitrosylation levels of GP, PFK and PK (P < 0.05). Moreover, GP expression in RFN pork was lower (P < 0.05) while no significant differences of PFK and PK expression were observed between these two groups. These data suggest that protein S-nitrosylation can presumably regulate glycolysis by modulating glycolytic enzymes activities and then regulate the development of PSE pork.


Assuntos
Glicólise , Músculo Esquelético/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/metabolismo , Carne de Porco/análise , Animais , Cor , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Músculo Esquelético/enzimologia , Fosfofrutoquinases/metabolismo , Piruvato Quinase/metabolismo , Suínos
5.
Org Biomol Chem ; 18(5): 931-940, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-31922157

RESUMO

The design of glycogen phosphorylase (GP) inhibitors targeting the catalytic site of the enzyme is a promising strategy for a better control of hyperglycaemia in the context of type 2 diabetes. Glucopyranosylidene-spiro-heterocycles have been demonstrated as potent GP inhibitors, and more specifically spiro-oxathiazoles. A new synthetic route has now been elaborated through 1,3-dipolar cycloaddition of an aryl nitrile oxide to a glucono-thionolactone affording in one step the spiro-oxathiazole moiety. The thionolactone was obtained from the thermal rearrangement of a thiosulfinate precursor according to Fairbanks' protocols, although with a revisited outcome and also rationalised with DFT calculations. The 2-naphthyl substituted glucose-based spiro-oxathiazole 5h, identified as one of the most potent GP inhibitors (Ki = 160 nM against RMGPb) could be produced on the gram-scale from this strategy. Further evaluation in vitro using rat and human hepatocytes demonstrated that compound 5h is a anti-hyperglycaemic drug candidates performing slightly better than DAB used as a positive control. Investigation in Zucker fa/fa rat model in acute and subchronic assays further confirmed the potency of compound 5h since it lowered blood glucose levels by ∼36% at 30 mg kg-1 and ∼43% at 60 mg kg-1. The present study is one of the few in vivo investigations for glucose-based GP inhibitors and provides data in animal models for such drug candidates.


Assuntos
Inibidores Enzimáticos/farmacologia , Glucose/metabolismo , Glicogênio Fosforilase/antagonistas & inibidores , Hipoglicemiantes/farmacologia , Compostos de Espiro/farmacologia , Tiazóis/farmacologia , Animais , Glicemia/metabolismo , Ciclização , Teoria da Densidade Funcional , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Concentração Inibidora 50 , Cinética , Lactonas/síntese química , Lactonas/química , Oxirredução , Ratos Zucker , Compostos de Espiro/síntese química , Compostos de Espiro/química , Estereoisomerismo , Temperatura , Tiazóis/síntese química , Tiazóis/química
6.
Food Chem ; 313: 126162, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31951884

RESUMO

The aim of this study was to assess the effects of the phosphorylation levels of glycogen phosphorylase on its activity in mutton sarcoplasmic protein samples during incubation at 4 °C. Samples of sarcoplasmic proteins from mutton longissimus thoracis muscles were prepared and separated into three treatment groups to obtain glycogen phosphorylase with different phosphorylation levels, which were (1) treated with protein kinase A, (2) treated with alkaline phosphatase, and (3) left untreated (control). Glycogen phosphorylase phosphorylation levels and activity as well as the levels of related endogenous substances were assessed. The results showed that phosphorylation of glycogen phosphorylase in mutton promoted its activity during incubation at 4 °C. The activity of glycogen phosphorylase was also influenced by other factors (glycogen, glucose, glucose 6-phosphate, ATP, etc.) in vitro. The combined effects of phosphorylation and endogenous substances on glycogen phosphorylase activity varied at different incubation times.


Assuntos
Glicogênio Fosforilase/metabolismo , Carne , Proteínas Musculares/metabolismo , Ovinos , Fosfatase Alcalina/metabolismo , Animais , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Glucose/metabolismo , Glicogênio/metabolismo , Masculino , Fosforilação , Temperatura
7.
Int J Mol Sci ; 20(23)2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31775340

RESUMO

McArdle disease, also known as glycogen storage disease type V (GSDV), is characterized by exercise intolerance, the second wind phenomenon, and high serum creatine kinase activity. Here, we recapitulate PYGM mutations in the population responsible for this disease. Traditionally, McArdle disease has been considered a metabolic myopathy caused by the lack of expression of the muscle isoform of the glycogen phosphorylase (PYGM). However, recent findings challenge this view, since it has been shown that PYGM is present in other tissues than the skeletal muscle. We review the latest studies about the molecular mechanism involved in glycogen phosphorylase activity regulation. Further, we summarize the expression and functional significance of PYGM in other tissues than skeletal muscle both in health and McArdle disease. Furthermore, we examine the different animal models that have served as the knowledge base for better understanding of McArdle disease. Finally, we give an overview of the latest state-of-the-art clinical trials currently being carried out and present an updated view of the current therapies.


Assuntos
Glicogênio Fosforilase/metabolismo , Doença de Depósito de Glicogênio Tipo V/patologia , Músculo Esquelético/patologia , Animais , Doença de Depósito de Glicogênio Tipo V/enzimologia , Humanos , Músculo Esquelético/enzimologia
8.
Adv Neurobiol ; 23: 125-145, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31667807

RESUMO

Glycogen constitutes the main store of glucose in animal cells. Being present at much lower concentrations in the brain than in liver and muscles, brain glycogen has long been considered as an emergency source of glucose, mobilized under stress conditions (including hypoglyceamia). Nevertheless, over the past decade, multiple studies have shed a new light on the roles of brain glycogen, being notably an energy supply critical for high-cognitive processes such as learning and memory consolidation. Glycogen phosphorylase (GP) is the key enzyme regulating the mobilization of glycogen in cells. It is found in humans as three isozymes: muscle (mGP), liver (lGP) and brain GP (bGP). In the brain, astrocytes express both mGP and bGP while neurons only express the brain isoform. Although GP isozymes are very similar, their distinct regulatory features confer them distinct metabolic functions that are strongly related to the roles of glycogen in different tissues. Here, we provide an overview of the functions, the regulations and the structures of GPs in the brain and their relation to the specific roles of glycogen in astrocytes and neurons. We also discuss novel findings concerning the specific regulations of bGP by oxidative stress, and the potential of these enzymes as therapeutic targets in the brain.


Assuntos
Encéfalo/enzimologia , Glicogênio Fosforilase/química , Glicogênio Fosforilase/metabolismo , Glicogênio , Animais , Encéfalo/metabolismo , Glicogênio/metabolismo , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Fígado/enzimologia , Fígado/metabolismo , Músculos/enzimologia , Músculos/metabolismo
9.
Brain ; 142(12): 3771-3790, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31647549

RESUMO

It is important to understand how the disease process affects the metabolic pathways in amyotrophic lateral sclerosis and whether these pathways can be manipulated to ameliorate disease progression. To analyse the basis of the metabolic defect in amyotrophic lateral sclerosis we used a phenotypic metabolic profiling approach. Using fibroblasts and reprogrammed induced astrocytes from C9orf72 and sporadic amyotrophic lateral sclerosis cases we measured the production rate of reduced nicotinamide adenine dinucleotides (NADH) from 91 potential energy substrates simultaneously. Our screening approach identified that C9orf72 and sporadic amyotrophic lateral sclerosis induced astrocytes have distinct metabolic profiles compared to controls and displayed a loss of metabolic flexibility that was not observed in fibroblast models. This loss of metabolic flexibility, involving defects in adenosine, fructose and glycogen metabolism, as well as disruptions in the membrane transport of mitochondrial specific energy substrates, contributed to increased starvation induced toxicity in C9orf72 induced astrocytes. A reduction in glycogen metabolism was attributed to loss of glycogen phosphorylase and phosphoglucomutase at the protein level in both C9orf72 induced astrocytes and induced neurons. In addition, we found alterations in the levels of fructose metabolism enzymes and a reduction in the methylglyoxal removal enzyme GLO1 in both C9orf72 and sporadic models of disease. Our data show that metabolic flexibility is important in the CNS in times of bioenergetic stress.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Astrócitos/metabolismo , Proteína C9orf72/metabolismo , Mitocôndrias/metabolismo , Neurônios Motores/metabolismo , Adulto , Idoso , Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Progressão da Doença , Metabolismo Energético , Feminino , Glicogênio Fosforilase/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade
10.
Cell Metab ; 30(5): 903-916.e7, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31523006

RESUMO

Nuclear glycogen was first documented in the early 1940s, but its role in cellular physiology remained elusive. In this study, we utilized pure nuclei preparations and stable isotope tracers to define the origin and metabolic fate of nuclear glycogen. Herein, we describe a key function for nuclear glycogen in epigenetic regulation through compartmentalized pyruvate production and histone acetylation. This pathway is altered in human non-small cell lung cancers, as surgical specimens accumulate glycogen in the nucleus. We demonstrate that the decreased abundance of malin, an E3 ubiquitin ligase, impaired nuclear glycogenolysis by preventing the nuclear translocation of glycogen phosphorylase and causing nuclear glycogen accumulation. Re-introduction of malin in lung cancer cells restored nuclear glycogenolysis, increased histone acetylation, and decreased growth of cancer cells transplanted into mice. This study uncovers a previously unknown role for glycogen metabolism in the nucleus and elucidates another mechanism by which cellular metabolites control epigenetic regulation.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Núcleo Celular/metabolismo , Glicogenólise/genética , Histonas/metabolismo , Neoplasias Pulmonares/metabolismo , Células A549 , Acetilação , Animais , Carbono/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Glicogênio/biossíntese , Glicogênio Fosforilase/metabolismo , Células HEK293 , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Knockout , Camundongos Nus , Transfecção , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
11.
J Food Biochem ; 43(3): e12764, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31353550

RESUMO

This study investigated the effects of Raffia palm wine (RPW) on redox imbalance, glycolytic and cholinergic enzymes, and ATPase activities in hyperglycemia-induced oxidative testicular injury. Type 2 diabetes (T2D) was induced in male albino rats (Sprague-Dawley) by first administering 10% fructose solution for 14 days, before injecting with an intraperitoneal injection (40 mg/kg body weight) of streptozotocin. Raffia palm wine was administered to two diabetic groups at 150 and 300 mg/kg body weight (bw), when untreated diabetic group was used as a negative control, and metformin-fed group was served as a positive control. The rats were sacrificed after 5 weeks of treatment, and testes were harvested. Treatment with RPW led to lower levels of nitric oxide, malondialdehyde and myeloperoxidase activity, with concomitant elevation of reduced glutathione level, superoxide dismutase, catalase and ATPase activities. Raffia palm wine also inhibited glycogen phosphorylase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and acetylcholinesterase, while restoring the altered testicular morphology to near-normal. The results of this study suggest the therapeutic potentials of RPW against the effects of T2D on testicular functions and morphology. PRACTICAL APPLICATIONS: Diabetes mellitus is one of the fastest growing global epidemy, with most developing countries being at the receiving end owing to the cost of treatment. Testicular damage has been recognized as one of the complications of diabetes, and if left untreated will lead to erectile dysfunction followed by infertility. Raffia palm wine is among the common natural beverage in West Africa, which is utilized for both social and medicinal purposes. In this study, for the first time we showed its ability to protect diabetes-induced testicular injury in type 2 diabetic rats. This may be of great benefit in managing diabetes associated erectly dysfunction and male infertility, as Raffia palm wine is readily available in all seasons. This study will also improve the medicinal use of this wine, which may also indirectly improve its commercial benefit.


Assuntos
Arecaceae/química , Diabetes Mellitus Tipo 2/complicações , Hiperglicemia/complicações , Doenças Testiculares/dietoterapia , Testículo/lesões , Vinho/análise , Animais , Catalase/metabolismo , Glicogênio Fosforilase/metabolismo , Glicólise , Humanos , Masculino , Malondialdeído/metabolismo , Óxido Nítrico/metabolismo , Oxirredução , Estresse Oxidativo , Peroxidase/metabolismo , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo , Doenças Testiculares/enzimologia , Doenças Testiculares/etiologia , Doenças Testiculares/metabolismo , Testículo/enzimologia , Testículo/metabolismo
12.
Biosci Rep ; 39(7)2019 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-31324732

RESUMO

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy with high morbidity and mortality rates and ranks as the sixth most common cancer all over the world. Despite numerous advancements in therapeutic methods, the prognosis of HNSCC patients still remains poor. Therefore, there is an urgent need to have a better understanding of the molecular mechanisms underlying HNSCC progression and to identify essential genes that could serve as effective biomarkers and potential treatment targets. In the present study, original data of three independent datasets were downloaded from the Gene Expression Omnibus database (GEO) and R language was applied to screen out the differentially expressed genes (DEGs). PYGM and TNNC2 were finally selected from the overlapping DEGs of three datasets for further analyses. Transcriptional and survival data related to PYGM and TNNC2 was detected through multiple online databases such as Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioportal, and UALCAN. Quantitative real-time polymerase chain reaction (qPCR) analysis was adopted for the validation of PYGM and TNNC2 mRNA level in HNSCC tissues and cell lines. Survival curves were plotted to evaluate the association of these two genes with HNSCC prognosis. It was demonstrated that PYGM and TNNC2 were significantly down-regulated in HNSCC and the aberrant expression of PYGM and TNNC2 were correlated with HNSCC prognosis, implying the potential of exploiting them as therapeutic targets for HNSCC treatment or potential biomarkers for diagnosis and prognosis.


Assuntos
Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/genética , Biologia Computacional , Glicogênio Fosforilase/genética , Neoplasias de Cabeça e Pescoço/genética , Proteínas de Neoplasias/genética , Troponina C/genética , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Bases de Dados de Ácidos Nucleicos , Glicogênio Fosforilase/metabolismo , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Proteínas de Neoplasias/metabolismo , Troponina C/metabolismo
13.
Top Curr Chem (Cham) ; 377(4): 19, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31165274

RESUMO

This review is an effort to summarize recent developments in synthesis of O-glycosides and N-, C-glycosyl molecules with promising antidiabetic potential. Articles published after 2000 are included. First, the O-glycosides used in the treatment of diabetes are presented, followed by the N-glycosides and finally the C-glycosides constituting the largest group of antidiabetic drugs are described. Within each group of glycosides, we presented how the structure of compounds representing potential drugs changes and when discussing chemical compounds of a similar structure, achievements are presented in the chronological order. C-Glycosyl compounds mimicking O-glycosides structure, exhibit the best features in terms of pharmacodynamics and pharmacokinetics. Therefore, the largest part of the article is concerned with the description of the synthesis and biological studies of various C-glycosides. Also N-glycosides such as N-(ß-D-glucopyranosyl)-amides, N-(ß-D-glucopyranosyl)-ureas, and 1,2,3-triazolyl derivatives belong to the most potent classes of antidiabetic agents. In order to indicate which of the compounds presented in the given sections have the best inhibitory properties, a list of the best inhibitors is presented at the end of each section. In summary, the best inhibitors were selected from each of the summarizing figures and the results of the ranking were placed. In this way, the reader can learn about the structure of the compounds having the best antidiabetic activity. The compounds, whose synthesis was described in the article but did not appear on the figures presenting the structures of the most active inhibitors, did not show proper activity as inhibitors. Thus, the article also presents studies that have not yielded the desired results and show directions of research that should not be followed. In order to show the directions of the latest research, articles from 2018 to 2019 are described in a separate Sect. 5. In Sect. 6, biological mechanisms of action of the glycosides and patents of marketed drugs are described.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Descoberta de Drogas/métodos , Glicosídeos/química , Glicosídeos/farmacologia , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Animais , Diabetes Mellitus/enzimologia , Diabetes Mellitus/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Glicogênio Fosforilase/antagonistas & inibidores , Glicogênio Fosforilase/metabolismo , Glicosídeos/farmacocinética , Glicosídeos/uso terapêutico , Humanos , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/uso terapêutico , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Inibidores do Transportador 2 de Sódio-Glicose/química , Inibidores do Transportador 2 de Sódio-Glicose/farmacocinética , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Relação Estrutura-Atividade
14.
ACS Chem Biol ; 14(7): 1460-1470, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31243960

RESUMO

Several C-ß-d-glucopyranosyl azoles have recently been uncovered as among the most potent glycogen phosphorylase (GP) catalytic site inhibitors discovered to date. Toward further exploring their translational potential, ex vivo experiments have been performed for their effectiveness in reduction of glycogenolysis in hepatocytes. New compounds for these experiments were predicted in silico where, for the first time, effective ranking of GP catalytic site inhibitor potencies using the molecular mechanics-generalized Born surface area (MM-GBSA) method has been demonstrated. For a congeneric training set of 27 ligands, excellent statistics in terms of Pearson (RP) and Spearman (RS) correlations (both 0.98), predictive index (PI = 0.99), and area under the receiver operating characteristic curve (AU-ROC = 0.99) for predicted versus experimental binding affinities were obtained, with ligand tautomeric/ionization states additionally considered using density functional theory (DFT). Seven 2-aryl-4(5)-(ß-d-glucopyranosyl)-imidazoles and 2-aryl-4-(ß-d-glucopyranosyl)-thiazoles were subsequently synthesized, and kinetics experiments against rabbit muscle GPb revealed new potent inhibitors with best Ki values in the low micromolar range (5c = 1.97 µM; 13b = 4.58 µM). Ten C-ß-d-glucopyranosyl azoles were then tested ex vivo in mouse primary hepatocytes. Four of these (5a-c and 9d) demonstrated significant reduction of glucagon stimulated glycogenolysis (IC50 = 30-60 µM). Structural and predicted physicochemical properties associated with their effectiveness were analyzed with permeability related parameters identified as crucial factors. The most effective ligand series 5 contained an imidazole ring, and the calculated pKa (Epik: 6.2; Jaguar 5.5) for protonated imidazole suggests that cellular permeation through the neutral state is favored, while within the cell, there is predicted more favorable binding to GP in the protonated form.


Assuntos
Azóis/farmacologia , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Glicogenólise/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Animais , Azóis/química , Células CACO-2 , Desenho de Fármacos , Inibidores Enzimáticos/química , Glicogênio Fosforilase/metabolismo , Hepatócitos/metabolismo , Humanos , Modelos Moleculares , Coelhos , Relação Estrutura-Atividade
15.
J Med Chem ; 62(13): 6116-6136, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31251604

RESUMO

Epimeric series of aryl-substituted glucopyranosylidene-spiro-imidazolinones, an unprecedented new ring system, were synthesized from the corresponding Schiff bases of O-perbenzoylated (gluculopyranosylamine)onamides by intramolecular ring closure of the aldimine moieties with the carboxamide group elicited by N-bromosuccinimide in pyridine. Test compounds were obtained by Zemplén O-debenzoylation. Stereochemistry and ring tautomers of the new compounds were investigated by NMR, time-dependent density functional theory (TDDFT)-electronic circular dichroism, and DFT-NMR methods. Kinetic studies with rabbit muscle and human liver glycogen phosphorylases showed that the (R)-imidazolinones were 14-216 times more potent than the (S) epimers. The 2-naphthyl-substituted (R)-imidazolinone was the best inhibitor of the human enzyme (Ki 1.7 µM) and also acted on HepG2 cells (IC50 177 µM). X-ray crystallography revealed that only the (R) epimers bound in the crystal. Their inhibitory efficacy is based on the hydrogen-bonding interactions of the carbonyl oxygen and the NH of the imidazolinone ring.


Assuntos
Inibidores Enzimáticos/farmacologia , Glucosídeos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Imidazolinas/farmacologia , Compostos de Espiro/farmacologia , Animais , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Glucosídeos/síntese química , Glucosídeos/metabolismo , Glicogênio Fosforilase/química , Glicogênio Fosforilase/metabolismo , Células Hep G2 , Humanos , Ligação de Hidrogênio , Imidazolinas/síntese química , Imidazolinas/metabolismo , Cinética , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Coelhos , Compostos de Espiro/síntese química , Compostos de Espiro/metabolismo , Estereoisomerismo
16.
Food Chem ; 293: 537-544, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151645

RESUMO

To verify the effect of protein phosphorylation on glycolysis and elucidate the regulatory mechanism from the perspective of enzyme activity, ovine muscle was treated with a kinase inhibitor, dimethyl sulfoxide, or a phosphatase inhibitor and the activities of glycogen phosphorylase, pyruvate kinase and phosphofructokinase were determined. The protein phosphorylation level was significantly different after incubation of muscle with kinase or phosphatase inhibitors. The pH value and lactate content revealed that a high phosphorylation level was the reason for the fast glycolysis. The glycogen phosphorylase, pyruvate kinase and phosphofructokinase activities were significantly higher in the phosphatase inhibitor group than in the other two groups (p < 0.05). Therefore, protein phosphorylation is involved in activating these three enzymes. In summary, protein phosphorylation plays a role in post-mortem glycolysis through the regulation of enzyme activity in ovine muscle.


Assuntos
Glicogênio Fosforilase/metabolismo , Músculos/enzimologia , Fosfofrutoquinases/metabolismo , Piruvato Quinase/metabolismo , Animais , Ensaios Enzimáticos , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Glicólise/efeitos dos fármacos , Fosfofrutoquinases/antagonistas & inibidores , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Piruvato Quinase/antagonistas & inibidores , Ovinos
17.
Biomed Pharmacother ; 112: 108715, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30970519

RESUMO

BACKGROUND: Dysregulation of glucose and glycogen metabolism are crucial mechanisms implicated in type 2 diabetes mellitus (T2DM). Centella asiatica (L.) Urban (Apiaceae) has been utilized as a traditional medicine in Africa and Asia for centuries and is commercially available as a dietary supplement. AIM: We explored for the first time, the possible efficacy of Centella asiatica (CA) extract in ameliorating T2DM-induced changes in key enzymes involved in glucose and glycogen metabolism in the rat skeletal muscle. METHODS: Diabetic rats were orally treated with vehicle, CA (500 and 1000 mg/kg) or metformin (300 mg/kg) daily for 14 days. Skeletal muscle activities of hexokinase (HK), phosphofructokinase (PFK) and fructose 1,6-bisphosphatase (FBPase) were determined by spectrophotometric assays while those of glycogen synthase (GS) and glycogen phosphorylase (GP) were assayed radio-chemically. Histological examination of skeletal muscle was also performed. RESULTS: Rats with induced T2DM had reduced activities of HK (25%), PFK (88%), and GS (38%) when compared to non-diabetic rats. Treatment of diabetic rats with CA500 increased the activities of PFK (7-fold), and FBPase (23%). Further, treatment of diabetic rats with CA1000 also increased the activities of GS (27%) and GP (50%) with little change in these parameters for diabetic rats treated with CA500. These effects probably led to the reduced blood glucose level and elevated skeletal muscle glycogen content observed in CA-treated rats relative to diabetic controls. Furthermore, CA treated rats had reduced the morphological damage of skeletal muscle fibres compared to the non-treated diabetic control rats. CONCLUSION: Our findings strongly suggest that the anti-diabetic effects of CA in part target muscle glucose and glycogen metabolism and hence supporting its folkloric medical use as an anti-diabetic remedy.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucose/metabolismo , Glicogênio/metabolismo , Hipoglicemiantes/uso terapêutico , Músculo Esquelético/efeitos dos fármacos , Triterpenos/uso terapêutico , Animais , Glicemia/análise , Centella/química , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Hipoglicemiantes/farmacologia , Masculino , Medicina Tradicional , Músculo Esquelético/enzimologia , Músculo Esquelético/patologia , Folhas de Planta/química , Ratos Sprague-Dawley , Estreptozocina , Triterpenos/farmacologia
18.
PLoS Biol ; 17(3): e2006146, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30860988

RESUMO

Stress responses are crucial processes that require activation of genetic programs that protect from the stressor. Stress responses are also energy consuming and can thus be deleterious to the organism. The mechanisms coordinating energy consumption during stress response in multicellular organisms are not well understood. Here, we show that loss of the epigenetic regulator G9a in Drosophila causes a shift in the transcriptional and metabolic responses to oxidative stress (OS) that leads to decreased survival time upon feeding the xenobiotic paraquat. During OS exposure, G9a mutants show overactivation of stress response genes, rapid depletion of glycogen, and inability to access lipid energy stores. The OS survival deficiency of G9a mutants can be rescued by a high-sugar diet. Control flies also show improved OS survival when fed a high-sugar diet, suggesting that energy availability is generally a limiting factor for OS tolerance. Directly limiting access to glycogen stores by knocking down glycogen phosphorylase recapitulates the OS-induced survival defects of G9a mutants. We propose that G9a mutants are sensitive to stress because they experience a net reduction in available energy due to (1) rapid glycogen use, (2) an inability to access lipid energy stores, and (3) an overinduced transcriptional response to stress that further exacerbates energy demands. This suggests that G9a acts as a critical regulatory hub between the transcriptional and metabolic responses to OS. Our findings, together with recent studies that established a role for G9a in hypoxia resistance in cancer cell lines, suggest that G9a is of wide importance in controlling the cellular and organismal response to multiple types of stress.


Assuntos
Histona Metiltransferases/metabolismo , Animais , Antioxidantes/metabolismo , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Epigênese Genética/genética , Glicogênio Fosforilase/genética , Glicogênio Fosforilase/metabolismo , Histona Metiltransferases/genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Masculino , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Filogenia , Análise de Sequência de RNA
19.
Phys Chem Chem Phys ; 21(14): 7685-7696, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30912774

RESUMO

A fluorescence study of N1-(ß-d-glucopyranosyl)-N4-[2-acridin-9(10H)-onyl]-cytosine (GLAC), the first fluorescent potent inhibitor of glycogen phosphorylase (GP), in neutral aqueous solution, is presented herein. Quantum chemistry (TD-DFT) calculations show the existence of several conformers both in the ground and first excited states. They result from rotations of the acridone and cytosine moieties around an NH bridge which may lead to the formation of non-emitting charge-transfer states. The fingerprints of various conformers have been detected by time-resolved fluorescence spectroscopy (fluorescence upconversion and time-correlated single photon counting) and identified using as criteria their energy, polarization and relative population resulting from computations. Such an analysis should contribute to the design of new GP inhibitors with better fluorescence properties, suitable for imaging applications.


Assuntos
Inibidores Enzimáticos/metabolismo , Glicogênio Fosforilase/metabolismo , Teoria Quântica , Acridonas/síntese química , Acridonas/química , Acridonas/metabolismo , Benzoatos/síntese química , Benzoatos/química , Benzoatos/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Glicogênio Fosforilase/antagonistas & inibidores , Espectrometria de Fluorescência , Termodinâmica
20.
Development ; 146(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30918052

RESUMO

The polysaccharide glycogen is an evolutionarily conserved storage form of glucose. However, the physiological significance of glycogen metabolism on homeostatic control throughout the animal life cycle remains incomplete. Here, we describe Drosophila mutants that have defective glycogen metabolism. Null mutants of glycogen synthase (GlyS) and glycogen phosphorylase (GlyP) displayed growth defects and larval lethality, indicating that glycogen plays a crucial role in larval development. Unexpectedly, however, a certain population of larvae developed into adults with normal morphology. Semi-lethality in glycogen mutants during the larval period can be attributed to the presence of circulating sugar trehalose. Homozygous glycogen mutants produced offspring, indicating that glycogen stored in oocytes is dispensable for embryogenesis. GlyS and GlyP mutants showed distinct metabolic defects in the levels of circulating sugars and triglycerides in a life stage-specific manner. In adults, glycogen as an energy reserve is not crucial for physical fitness and lifespan under nourished conditions, but glycogen becomes important under energy stress conditions. This study provides a fundamental understanding of the stage-specific requirements for glycogen metabolism in the fruit fly.


Assuntos
Proteínas de Drosophila/metabolismo , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Animais , Drosophila , Proteínas de Drosophila/genética , Feminino , Glicogênio/metabolismo , Glicogênio Fosforilase/genética , Glicogênio Sintase/genética , Masculino , Trealose/metabolismo
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