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1.
Nat Commun ; 11(1): 4627, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009389

RESUMO

Animals have evolved responses to low oxygen conditions to ensure their survival. Here, we have identified the C. elegans zinc finger transcription factor PQM-1 as a regulator of the hypoxic stress response. PQM-1 is required for the longevity of insulin signaling mutants, but surprisingly, loss of PQM-1 increases survival under hypoxic conditions. PQM-1 functions as a metabolic regulator by controlling oxygen consumption rates, suppressing hypoxic glycogen levels, and inhibiting the expression of the sorbitol dehydrogenase-1 SODH-1, a crucial sugar metabolism enzyme. PQM-1 promotes hypoxic fat metabolism by maintaining the expression of the stearoyl-CoA desaturase FAT-7, an oxygen consuming, rate-limiting enzyme in fatty acid biosynthesis. PQM-1 activity positively regulates fat transport to developing oocytes through vitellogenins under hypoxic conditions, thereby increasing survival rates of arrested progeny during hypoxia. Thus, while pqm-1 mutants increase survival of mothers, ultimately this loss is detrimental to progeny survival. Our data support a model in which PQM-1 controls a trade-off between lipid metabolic activity in the mother and her progeny to promote the survival of the species under hypoxic conditions.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Hipóxia/metabolismo , Metabolismo dos Lipídeos , Transativadores/metabolismo , Animais , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Embrião de Mamíferos/metabolismo , Regulação da Expressão Gênica , Glicogênio/metabolismo , Insulina/metabolismo , Larva/metabolismo , Mutação/genética , Consumo de Oxigênio , Transdução de Sinais , Estresse Fisiológico , Análise de Sobrevida , Transativadores/genética , Transcrição Genética , Vitelogeninas/metabolismo
2.
PLoS One ; 15(9): e0239358, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970715

RESUMO

There is an extensive literature establishing, validating, and quantifying a wide range of responses of fishes to fasting. Our study complements this work by comparing fed and unfed treatments of hatchery-raised Delta Smelt (Hypomesus transpacificus)-an imperiled fish that is endemic to the San Francisco Estuary and its tributaries in California, USA-across a diverse suite of endpoints over a two-month time series. The experiment was conducted at 15.9°C, and individuals were sampled at 12 time points as starvation became increasingly severe. We found that hepatosomatic index and condition factor were relatively sensitive to starvation, becoming significantly depressed at Day 4 and 7, respectively. Histological analysis of liver showed elevated cytoplasmic inclusion bodies at Day 7, followed by increased glycogen depletion, single cell necrosis, and hydropic vacuolar degeneration at Day 14, 21, and 28, respectively. Of four antioxidants measured, glutathione decreased at Day 4, superoxide dismutase increased at Day 14, catalase increased at Day 56, and glutathione peroxidase was not affected by starvation. The net result was a ~2-fold increase in lipid peroxidation (malondialdehyde) in fasted fish that was highly inconsistent through time. RNA to DNA ratio and triglycerides in muscle were relatively insensitive to starvation, only consistently decreasing with fasting after mortality began increasing in the 'No Feeding' treatment, at Day 21. Together, these results suggest that Delta Smelt mobilize hepatic energy stores far more rapidly than lipids in muscle when subjected to fasting, leading to rapid atrophy of liver and the development of cytoplasmic inclusion bodies-possibly autophagosomes-in hepatocytes.


Assuntos
Osmeriformes/metabolismo , Inanição , Animais , Catalase/metabolismo , Glutationa/metabolismo , Glicogênio/metabolismo , Corpos de Inclusão/metabolismo , Fígado/metabolismo , Fígado/patologia , Malondialdeído/metabolismo , Músculos/metabolismo , Músculos/patologia , Necrose , Osmeriformes/crescimento & desenvolvimento , Superóxido Dismutase/metabolismo , Fatores de Tempo
3.
Nat Commun ; 11(1): 4706, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943618

RESUMO

Yeast physiology is temporally regulated, this becomes apparent under nutrient-limited conditions and results in respiratory oscillations (YROs). YROs share features with circadian rhythms and interact with, but are independent of, the cell division cycle. Here, we show that YROs minimise energy expenditure by restricting protein synthesis until sufficient resources are stored, while maintaining osmotic homeostasis and protein quality control. Although nutrient supply is constant, cells sequester and store metabolic resources via increased transport, autophagy and biomolecular condensation. Replete stores trigger increased H+ export which stimulates TORC1 and liberates proteasomes, ribosomes, chaperones and metabolic enzymes from non-membrane bound compartments. This facilitates translational bursting, liquidation of storage carbohydrates, increased ATP turnover, and the export of osmolytes. We propose that dynamic regulation of ion transport and metabolic plasticity are required to maintain osmotic and protein homeostasis during remodelling of eukaryotic proteomes, and that bioenergetic constraints selected for temporal organisation that promotes oscillatory behaviour.


Assuntos
Metabolismo Energético/fisiologia , Células Eucarióticas/fisiologia , Proteostase/fisiologia , Autofagia/fisiologia , Reatores Biológicos , Ritmo Circadiano , Glicogênio/metabolismo , Resposta ao Choque Térmico , Ionomicina , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metabolômica , Chaperonas Moleculares , Concentração Osmolar , Pressão Osmótica , Oxigênio/metabolismo , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteoma , Proteômica , Ribossomos , Leveduras/fisiologia
4.
PLoS Negl Trop Dis ; 14(8): e0008669, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866146

RESUMO

Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher's Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20-hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF.


Assuntos
Aedes/efeitos dos fármacos , Culicidae/efeitos dos fármacos , Inseticidas/farmacologia , Metoprene/metabolismo , Esterilização , Animais , Ecdisterona/farmacologia , Corpo Adiposo/crescimento & desenvolvimento , Feminino , Glicogênio/metabolismo , Proteínas de Insetos/genética , Hormônios Juvenis/farmacologia , Ovário/crescimento & desenvolvimento , Piridinas , Interferência de RNA , Triglicerídeos/metabolismo
5.
Ecotoxicol Environ Saf ; 204: 111005, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32738624

RESUMO

Freezing temperatures is an important stressor in the arctic regions and has a significant influence on the population dynamics and geographic distribution of terrestrial invertebrates. Toxic metals in the environment can interfere with protective cold-acclimation responses of organisms. It is therefore important to evaluate the combined effects of cold stress and environmental contaminants. Here, we aimed to investigate the effects of Hg (HgCl2) on various physiological aspects of freeze-tolerance in the earthworm (Enchytraeus albidus). We measured the levels of the cryoprotectant glucose, the glycogen content (source of glucose molecules for cryoprotection and fuel for metabolism), and changes in the composition of membrane phospholipid fatty acids (PLFA) as an indicator of lipid peroxidation. Freezing at -6 °C had no effect on survival in uncontaminated soil, however, survival of freezing in Hg contaminated soil was clearly reduced, especially at extended exposure times. Thus, the LC50 value in frozen soil decreased from 8.3 mg Hg kg-1 (when exposed for 17 days) to only 4.2 mg Hg kg-1 after 36 days' exposure indicating that combined effects of Hg and freezing became larger at prolonged exposure times. Hg caused a depletion of glycogen reserves (almost 50% at 12 mg kg-1 dry soil), but despite this effect worms were able to maintain a constant cryoprotectant level (about 0.12 mg glucose mg-1 dry weight) at all Hg concentrations. Hg had clear negative effects on the proportion of unsaturated PLFAs, which could be an indication of lipid peroxidation. Since a high proportion of unsaturated fatty acids in the membrane is important for invertebrate freeze-tolerance, our results suggest that the negative effect of Hg on freeze-tolerance in E. albidus is related to degraded membrane functionality at low temperature.


Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Congelamento , Cloreto de Mercúrio/efeitos adversos , Oligoquetos/efeitos dos fármacos , Animais , Crioprotetores/farmacologia , Relação Dose-Resposta a Droga , Ácidos Graxos/metabolismo , Glucose/farmacologia , Glicogênio/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Mercúrio/efeitos adversos
6.
PLoS Biol ; 18(6): e3000732, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32603375

RESUMO

Coordination of gene expression with nutrient availability supports proliferation and homeostasis and is shaped by protein acetylation. Yet how physiological/pathological signals link acetylation to specific gene expression programs and whether such responses are cell-type-specific is unclear. AMP-activated protein kinase (AMPK) is a key energy sensor, activated by glucose limitation to resolve nutrient supply-demand imbalances, critical for diabetes and cancer. Unexpectedly, we show here that, in gastrointestinal cancer cells, glucose activates AMPK to selectively induce EP300, but not CREB-binding protein (CBP). Consequently, EP300 is redirected away from nuclear receptors that promote differentiation towards ß-catenin, a driver of proliferation and colorectal tumorigenesis. Importantly, blocking glycogen synthesis permits reactive oxygen species (ROS) accumulation and AMPK activation in response to glucose in previously nonresponsive cells. Notably, glycogen content and activity of the ROS/AMPK/EP300/ß-catenin axis are opposite in healthy versus tumor sections. Glycogen content reduction from healthy to tumor tissue may explain AMPK switching from tumor suppressor to activator during tumor evolution.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Neoplasias Colorretais/metabolismo , Proteína p300 Associada a E1A/metabolismo , Glucose/farmacologia , Animais , Proteína de Ligação a CREB/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias Colorretais/patologia , Ativação Enzimática/efeitos dos fármacos , Glicogênio/metabolismo , Camundongos Endogâmicos C57BL , Ligação Proteica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , beta Catenina/metabolismo
7.
PLoS One ; 15(7): e0235702, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634159

RESUMO

Rheumatoid arthritis (RA) is accompanied by pain, inflammation and muscle weakness. Skeletal muscle inflammation and inactivity are independently associated with muscle insulin resistance and atrophy. Our objective was to identify early molecular and biochemical markers in muscle from a rodent model of RA relative to control and subsequently identify commonality in muscle gene expression between this model and muscle from RA patients. Pain behaviour and locomotor activity were measured in a collagen-induced arthritis (CIA) model of RA (n = 9) and control (n = 9) rats. Energy substrates and metabolites, total alkaline-soluble protein:DNA ratio and mRNA abundance of 46 targeted genes were also determined in Extensor digitorum longus muscle. Expression of targeted mRNAs was quantified in Vastus Lateralis muscle from RA patients (n = 7) and healthy age-matched control volunteers (n = 6). CIA rats exhibited pain behaviour (p<0.01) and reduced activity (p<0.05) compared to controls. Muscle glycogen content was less (p<0.05) and muscle lactate content greater (p<0.01) in CIA rats. The bioinformatics analysis of muscle mRNA abundance differences from the control, predicted the activation of muscle protein metabolism and inhibition of muscle carbohydrate and fatty acid metabolism in CIA rats. Compared to age-matched control volunteers, RA patients exhibited altered muscle mRNA expression of 8 of the transcripts included as targets in the CIA model of RA. In conclusion, muscle energy metabolism and metabolic gene expression were altered in the CIA model, which was partly corroborated by targeted muscle mRNA measurements in RA patients. This research highlights the negative impact of RA on skeletal muscle metabolic homeostasis.


Assuntos
Artrite Reumatoide/complicações , Músculo Esquelético/metabolismo , Doenças Musculares/etiologia , Idoso , Animais , Artrite Experimental/metabolismo , Artrite Reumatoide/metabolismo , Biomarcadores , Modelos Animais de Doenças , Feminino , Glicogênio/metabolismo , Humanos , Inflamação , Locomoção , Pessoa de Meia-Idade , Doenças Musculares/metabolismo , Mialgia/etiologia , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos Lew , Transcriptoma
8.
BMC Evol Biol ; 20(1): 93, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727355

RESUMO

BACKGROUND: The adaptive significance of phenotypic changes elicited by environmental conditions experienced early in life has long attracted attention in evolutionary biology. In this study, we used Drosophila melanogaster to test whether the developmental diet produces phenotypes better adapted to cope with similar nutritional conditions later in life. To discriminate among competing hypotheses on the underlying nature of developmental plasticity, we employed a full factorial design with several developmental and adult diets. Specifically, we examined the effects of early- and late-life diets (by varying their yeast and sugar contents) on reproductive fitness and on the amount of energy reserves (fat and glycogen) in two wild-caught populations. RESULTS: We found that individuals that had developed on either low-yeast or high-sugar diet showed decreased reproductive performance regardless of their adult nutritional environment. The lower reproductive fitness might be caused by smaller body size and reduced ovariole number. Overall, these results are consistent with the silver spoon concept, which posits that development in a suboptimal environment negatively affects fitness-associated traits. On the other hand, the higher amount of energy reserves (fat) in individuals that had developed in a suboptimal environment might represent either an adaptive response or a side-effect of compensatory feeding. CONCLUSION: Our findings suggest that the observed differences in the adult physiology induced by early-life diet likely result from inevitable and general effects of nutrition on the development of reproductive and metabolic organs, rather than from adaptive mechanisms.


Assuntos
Dieta , Drosophila melanogaster/metabolismo , Drosophila melanogaster/fisiologia , Tecido Adiposo/metabolismo , Animais , Tamanho Corporal , Metabolismo Energético , Feminino , Fertilidade , Aptidão Genética , Glicogênio/metabolismo , Masculino , Fenótipo , Reprodução , Açúcares/análise , Leveduras
9.
Food Chem ; 333: 127527, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32683263

RESUMO

The aim of this study was to develop a novel fermented soybean food (FSF) using selected Bacillus subtilis GD1, Bacillus subtilis N4, Bacillus velezensis GZ1, Lactobacillus delbrueckii subsp. bulgaricus and Hansenula anomala, as well as to assess its antioxidant and anti-fatigue activity. These Bacillus strains had excellent enzyme producing and soybean transformation capacity. FSF showed the highest peptide, total phenol, total flavonoid content, antioxidant activity, and suitable organic acid and biological amine content. In intense exercise mice, FSF treatment markedly increased hepatic glycogen level, decreased metabolite accumulation, improved the activities of antioxidant enzymes and decreased malondialdehyde (MDA) level in serum and liver, respectively. Furthermore, FSF treatment increased nuclear factor-erythroid 2-related factor 2 (Nrf2) and antioxidant response element (ARE)-dependent gene expression. Together, the selection of microbial starter culture and mixed culture fermentation are essential for the effective enrichment of bioactive compounds, and FSF has stronger antioxidant and anti-fatigue activity.


Assuntos
Antioxidantes/metabolismo , Bacillus/metabolismo , Alimentos e Bebidas Fermentados/análise , Lactobacillus/metabolismo , Pichia/metabolismo , Soja/metabolismo , Animais , Antioxidantes/farmacologia , Bacillus/crescimento & desenvolvimento , Nitrogênio da Ureia Sanguínea , Fadiga/metabolismo , Fadiga/patologia , Flavonoides/análise , Glicogênio/metabolismo , Lactobacillus/crescimento & desenvolvimento , Fígado/metabolismo , Masculino , Malondialdeído/sangue , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fenóis/análise , Condicionamento Físico Animal , Pichia/crescimento & desenvolvimento , Soja/química
11.
Proc Natl Acad Sci U S A ; 117(32): 19209-19220, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723826

RESUMO

Some organisms have evolved a survival strategy to withstand severe dehydration in an ametabolic state, called anhydrobiosis. The only known example of anhydrobiosis among insects is observed in larvae of the chironomid Polypedilum vanderplanki Recent studies have led to a better understanding of the molecular mechanisms underlying anhydrobiosis and the action of specific protective proteins. However, gene regulation alone cannot explain the rapid biochemical reactions and independent metabolic changes that are expected to sustain anhydrobiosis. For this reason, we conducted a comprehensive comparative metabolome-transcriptome analysis in the larvae. We showed that anhydrobiotic larvae adopt a unique metabolic strategy to cope with complete desiccation and, in particular, to allow recovery after rehydration. We argue that trehalose, previously known for its anhydroprotective properties, plays additional vital roles, providing both the principal source of energy and also the restoration of antioxidant potential via the pentose phosphate pathway during the early stages of rehydration. Thus, larval viability might be directly dependent on the total amount of carbohydrate (glycogen and trehalose). Furthermore, in the anhydrobiotic state, energy is stored as accumulated citrate and adenosine monophosphate, allowing rapid reactivation of the citric acid cycle and mitochondrial activity immediately after rehydration, before glycolysis is fully functional. Other specific adaptations to desiccation include potential antioxidants (e.g., ophthalmic acid) and measures to avoid the accumulation of toxic waste metabolites by converting these to stable and inert counterparts (e.g., xanthurenic acid and allantoin). Finally, we confirmed that these metabolic adaptations correlate with unique organization and expression of the corresponding enzyme genes.


Assuntos
Dípteros/metabolismo , Proteínas de Insetos/metabolismo , Monofosfato de Adenosina/metabolismo , Animais , Dessecação , Dípteros/química , Dípteros/genética , Secas , Glicogênio/genética , Glicogênio/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/genética , Larva/química , Larva/genética , Larva/metabolismo , Metaboloma , Transcriptoma , Trealose/metabolismo , Água/metabolismo
12.
J Toxicol Sci ; 45(6): 339-347, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32493876

RESUMO

The metabolomic profiles of rat primary hepatocytes following treatment with rotenone, FCCP, or (+)-usnic acid were determined using liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-mass spectrometry. Significant and similar changes in the levels of 283 biochemical metabolites were associated with the three treatments compared with solvent control samples. Overall, the three treatments generated similar global biochemical profiles, with some minor differences associated with rotenone treatment. All three treatments resulted in a shift in energy metabolism as demonstrated by decreased glycogen stores and glycolysis. A reduced antioxidant response was detected in cells following all treatments. In addition, bile acid biosynthesis decreased as a potential consequence of increased oxidative stress by all three treatments. Conversely, rotenone treatment induced a number of changes after 1 hr, which were not detected in FCCP- or (+)-usnic acid-treated samples; these changes were not sustained over time and included increased NAD+ salvage and lysine degradation. In conclusion, these biochemical profiles could provide new insights into the mechanism(s) of mitochondrial toxicity.


Assuntos
Benzofuranos/efeitos adversos , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/efeitos adversos , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Rotenona/efeitos adversos , Animais , Ácidos e Sais Biliares/metabolismo , Células Cultivadas , Cromatografia Líquida , Metabolismo Energético/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Glicogênio/metabolismo , Glicólise/efeitos dos fármacos , Metabolômica , Mitocôndrias Hepáticas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos Endogâmicos F344
13.
Food Chem ; 328: 127133, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32480263

RESUMO

To explore the molecular mechanisms of meat quality, four high-quality (HQ) samples and four low-quality (LQ) samples from longissimus dorsi muscles were chosen, and tandem mass tag (TMT) labeling combined with mass spectrometry (MS) were performed to find associations between meat quality and proteome profiles. The LQ meats had lower pH, lighter color, and higher drip loss compared to the HQ meats. About 140 differentially expressed proteins were identified. Functional analysis results of differentially expressed proteins showed that decreased release of Ca2+, lower contents of type II fibers, lower contents of glycogen, and decreased glycogenolysis in HQ meats indicated a lower degree of glycolysis in HQ as compared to LQ meats. Meanwhile, some differentially expressed proteins suggested that the levels of oxidative stress and apoptosis were lower in HQ meats than in LQ meats. This study reveals physiological changes between HQ and LQ meats according to the proteome profiles.


Assuntos
Proteínas de Carne/análise , Músculo Esquelético/química , Proteômica/métodos , Carne Vermelha/análise , Espectrometria de Massas em Tandem/métodos , Animais , Apoptose , Autopsia , Qualidade dos Alimentos , Glicogênio/análise , Glicogênio/metabolismo , Glicólise , Proteínas de Carne/metabolismo , Músculo Esquelético/metabolismo , Estresse Oxidativo , Suínos
14.
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
15.
Science ; 368(6490)2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32355002

RESUMO

Repeated bouts of exercise condition muscle mitochondria to meet increased energy demand-an adaptive response associated with improved metabolic fitness. We found that the type 2 cytokine interleukin-13 (IL-13) is induced in exercising muscle, where it orchestrates metabolic reprogramming that preserves glycogen in favor of fatty acid oxidation and mitochondrial respiration. Exercise training-mediated mitochondrial biogenesis, running endurance, and beneficial glycemic effects were lost in Il13-/- mice. By contrast, enhanced muscle IL-13 signaling was sufficient to increase running distance, glucose tolerance, and mitochondrial activity similar to the effects of exercise training. In muscle, IL-13 acts through both its receptor IL-13Rα1 and the transcription factor Stat3. The genetic ablation of either of these downstream effectors reduced running capacity in mice. Thus, coordinated immunological and physiological responses mediate exercise-elicited metabolic adaptations that maximize muscle fuel economy.


Assuntos
Adaptação Fisiológica/imunologia , Glicogênio/metabolismo , Interleucina-13/metabolismo , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Resistência Física/imunologia , Animais , Glicemia/metabolismo , Linhagem Celular , Ácidos Graxos/metabolismo , Feminino , Humanos , Interleucina-13/sangue , Interleucina-13/genética , Subunidade alfa1 de Receptor de Interleucina-13/genética , Subunidade alfa1 de Receptor de Interleucina-13/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mioblastos/metabolismo , Oxirredução , Condicionamento Físico Animal , Corrida , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo
16.
Am J Physiol Endocrinol Metab ; 318(6): E943-E955, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32369414

RESUMO

Myokines, such as irisin, have been purported to exert physiological effects on skeletal muscle in an autocrine/paracrine fashion. In this study, we aimed to investigate the mechanistic role of in vivo fibronectin type III domain-containing 5 (Fndc5)/irisin upregulation in muscle. Overexpression (OE) of Fndc5 in rat hindlimb muscle was achieved by in vivo electrotransfer, i.e., bilateral injections of Fndc5 harboring vectors for OE rats (n = 8) and empty vector for control rats (n = 8). Seven days later, a bolus of D2O (7.2 mL/kg) was administered via oral gavage to quantify muscle protein synthesis. After an overnight fast, on day 9, 2-deoxy-d-glucose-6-phosphate (2-DG6P; 6 mg/kg) was provided during an intraperitoneal glucose tolerance test (2 g/kg) to assess glucose handling. Animals were euthanized, musculus tibialis cranialis muscles and subcutaneous fat (inguinal) were harvested, and metabolic and molecular effects were evaluated. Muscle Fndc5 mRNA increased with OE (~2-fold; P = 0.014), leading to increased circulating irisin (1.5 ± 0.9 to 3.5 ± 1.2 ng/mL; P = 0.049). OE had no effect on protein anabolism or mitochondrial biogenesis; however, muscle glycogen was increased, along with glycogen synthase 1 gene expression (P = 0.04 and 0.02, respectively). In addition to an increase in glycogen synthase activation in OE (P = 0.03), there was a tendency toward increased glucose transporter 4 protein (P = 0.09). However, glucose uptake (accumulation of 2-DG6P) was identical. Irisin elicited no endocrine effect on mitochondrial biogenesis or uncoupling proteins in white adipose tissue. Hindlimb overexpression led to physiological increases in Fndc5/irisin. However, our data indicate limited short-term impacts of irisin in relation to muscle anabolism, mitochondrial biogenesis, glucose uptake, or adipose remodeling.


Assuntos
Fibronectinas/genética , Músculo Esquelético/metabolismo , Gordura Subcutânea/metabolismo , Animais , Desoxiglucose/metabolismo , Óxido de Deutério , Eletroporação , Fibronectinas/metabolismo , Expressão Gênica , Glucose/metabolismo , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 4/genética , Glucose-6-Fosfato/análogos & derivados , Glucose-6-Fosfato/metabolismo , Glicogênio/metabolismo , Glicogênio Sintase/genética , Glicogênio Sintase/metabolismo , Membro Posterior , Masculino , Proteínas de Desacoplamento Mitocondrial/genética , Biogênese de Organelas , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , Ratos
17.
J Food Sci ; 85(6): 1897-1906, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32449949

RESUMO

The anshenyizhi compound (AC), a mixture from Chinese medicine herbs, has numerous biological effects. In the present study, the acute exercise-treated mice model was established to explore the antifatigue properties of AC and its underlying mechanisms. AC increased exercise endurance in the weight-loaded forced swimming test and rota-rod test. The antifatigue properties of AC were closely correlated with enhancing the body's exercise endurance by increasing the levels of cyanmethemoglobin, testosterone/corticosterone, and creatine kinase, while decreasing the levels of lactic acid, lactate dehydrogenase, and blood urea nitrogen in serum. Moreover, our results confirmed the antioxidant ability of AC by improving the activities of superoxide dismutase while reducing reactive oxygen species and malondialdehyde levels in serum. The AC also improved the storage of glycogen by increasing the levels of succinate dehydrogenase, and malate dehydrogenase in liver and muscle. Additionally, AC displayed the antifatigue and antiapoptosis effects via regulating Nrf2-mediated oxidative stress, AMPK-related glucose metabolism, and p53 pathways. Our experimental results first provided a support that AC had effects on antifatigue through regulating AMPK/PGC-1α-related energy metabolism and Nrf2/ARE-mediated oxidative stress. Consequently, AC could be developed into a new functional food supplement for the prevention and treatment of diseases related to fatigue in the future.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Medicamentos de Ervas Chinesas/administração & dosagem , Fadiga/tratamento farmacológico , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Transativadores/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Elementos de Resposta Antioxidante/efeitos dos fármacos , Antioxidantes/metabolismo , Metabolismo Energético , Fadiga/genética , Fadiga/metabolismo , Glicogênio/metabolismo , Humanos , Fígado/metabolismo , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Fator 2 Relacionado a NF-E2/genética , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Natação , Transativadores/genética
18.
Am J Physiol Endocrinol Metab ; 319(1): E133-E145, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32459527

RESUMO

Bromocriptine mesylate treatment was examined in dogs fed a high fat diet (HFD) for 8 wk. After 4 wk on HFD, daily bromocriptine (Bromo; n = 6) or vehicle (CTR; n = 5) injections were administered. Oral glucose tolerance tests were performed before beginning HFD (OGTT1), 4 wk after HFD began (Bromo only), and after 7.5 wk on HFD (OGTT3). After 8 wk on HFD, clamp studies were performed, with infusion of somatostatin and intraportal replacement of insulin (4× basal) and glucagon (basal). From 0 to 90 min (P1), glucose was infused via peripheral vein to double the hepatic glucose load; and from 90 to 180 min (P2), glucose was infused via the hepatic portal vein at 4 mg·kg-1·min-1, with the HGL maintained at 2× basal. Bromo decreased the OGTT glucose ΔAUC0-30 and ΔAUC0-120 by 62 and 27%, respectively, P < 0.05 for both) without significantly altering the insulin response. Bromo dogs exhibited enhanced net hepatic glucose uptake (NHGU) compared with CTR (~33 and 21% greater, P1 and P2, respectively, P < 0.05). Nonhepatic glucose uptake (non-HGU) was increased ~38% in Bromo in P2 (P < 0.05). Bromo vs. CTR had higher (P < 0.05) rates of glucose infusion (36 and 30%) and non-HGU (~40 and 27%) than CTR during P1 and P2, respectively. In Bromo vs. CTR, hepatic 18:0/16:0 and 16:1/16:0 ratios tended to be elevated in triglycerides and were higher (P < 0.05) in phospholipids, consistent with a beneficial effect of bromocriptine on liver fat accumulation. Thus, bromocriptine treatment improved glucose disposal in a glucose-intolerant model, enhancing both NHGU and non-HGU.


Assuntos
Glicemia/efeitos dos fármacos , Bromocriptina/farmacologia , Dieta Hiperlipídica , Agonistas de Dopamina/farmacologia , Intolerância à Glucose/metabolismo , Fígado/efeitos dos fármacos , Animais , Glicemia/metabolismo , Cães , Ácidos Graxos não Esterificados/metabolismo , Glucagon/efeitos dos fármacos , Glucagon/metabolismo , Glucose/metabolismo , Técnica Clamp de Glucose , Teste de Tolerância a Glucose , Glicogênio/metabolismo , Veias Hepáticas , Insulina/metabolismo , Ácido Láctico/metabolismo , Fígado/metabolismo , Veia Porta , Somatostatina
19.
PLoS One ; 15(4): e0225922, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324778

RESUMO

Stored muscle carbohydrate supply and energetic efficiency constrain muscle functional capacity during exercise and are influenced by common physiological variables (e.g. age, diet, and physical activity level). Whether these constraints affect overall functional capacity or the timing of muscle energetic failure during acute hypoxia is not known. We interrogated skeletal muscle contractile properties in two anatomically distinct rodent hindlimb muscles that have well characterized differences in energetic efficiency (locomotory- extensor digitorum longus (EDL) and postural- soleus muscles) following a 24 hour fasting period that resulted in substantially reduced muscle carbohydrate supply. 180 mins of acute hypoxia resulted in complete energetic failure in all muscles tested, indicated by: loss of force production, substantial reductions in total adenosine nucleotide pool intermediates, and increased adenosine nucleotide degradation product-inosine monophosphate (IMP). These changes occurred in the absence of apparent myofiber structural damage assessed histologically by both transverse section and whole mount. Fasting and the associated reduction of the available intracellular carbohydrate pool (~50% decrease in skeletal muscle) did not significantly alter the timing to muscle functional impairment or affect the overall force/work capacities of either muscle type. Fasting resulted in greater passive tension development in both muscle types, which may have implications for the design of pre-clinical studies involving optimal timing of reperfusion or administration of precision therapeutics.


Assuntos
Jejum , Hipóxia/metabolismo , Contração Muscular , Músculo Esquelético/metabolismo , Nucleotídeos de Adenina/análise , Nucleotídeos de Adenina/metabolismo , Animais , Metabolismo Energético , Jejum/efeitos adversos , Glicogênio/análise , Glicogênio/metabolismo , Hipóxia/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Músculo Esquelético/fisiopatologia , Condicionamento Físico Animal
20.
PLoS One ; 15(4): e0230044, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236143

RESUMO

LEFTY2 (endometrial bleeding associated factor; EBAF or LEFTYA), a cytokine released shortly before menstrual bleeding, is a negative regulator of cell proliferation and tumour growth. LEFTY2 down-regulates Na+/H+ exchanger activity with subsequent inhibition of glycolytic flux and lactate production in endometrial cancer cells. Glucose can be utilized not only for glycolysis but also for glycogen formation. Both glycolysis and glycogen formation require cellular glucose uptake which could be accomplished by the Na+ coupled glucose transporter-1 (SGLT1; SLC5A1). The present study therefore explored whether LEFTY2 modifies endometrial SGLT1 expression and activity as well as glycogen formation. Ishikawa and HEC1a cells were exposed to LEFTY2, SGLT1 and glycogen synthase (GYS1) transcript levels determined by qRT-PCR. SGLT1, GYS1 and phospho-GYS1 protein abundance was quantified by western blotting, cellular glucose uptake from 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose (2-NBDG) uptake, and cellular glycogen content utilizing an enzymatic assay and subsequent colorimetry. As a result, a 48-hour treatment with LEFTY2 significantly increased SGLT1 and GYS1 transcript levels as well as SGLT1 and GYS1 protein abundance in both Ishikawa and HEC1a cells. 2-NBDG uptake and cellular glycogen content were upregulated significantly in Ishikawa (type 1) but not in type 2 endometrial HEC1a cells, although there was a tendency of increased 2-NBDG uptake. Further, none of the effects were seen in human benign endometrial cells (HESCs). Interestingly, in both Ishikawa and HEC1a cells, a co-treatment with TGF-ß reduced SGLT1, GYS and phospho-GYS protein levels, and thus reduced glycogen levels and again HEC1a cells had no significant change. In conclusion, LEFTY2 up-regulates expression and activity of the Na+ coupled glucose transporter SGLT1 and glycogen synthase GYS1 in a cell line specific manner. We further show the treatment with LEFTY2 fosters cellular glucose uptake and glycogen formation and TGF-ß can negate this effect in endometrial cancer cells.


Assuntos
Neoplasias do Endométrio/metabolismo , Endométrio/metabolismo , Glicogênio Sintase/metabolismo , Glicogênio/metabolismo , Fatores de Determinação Direita-Esquerda/fisiologia , Transportador 1 de Glucose-Sódio/metabolismo , Linhagem Celular Tumoral , Feminino , Glucose/metabolismo , Humanos , Sódio/metabolismo
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