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1.
BMC Med ; 22(1): 106, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454391

RESUMO

BACKGROUND: Breastfeeding (BF) confers metabolic benefits to infants, including reducing risks of metabolic syndrome such as obesity and diabetes later in life. However, the underlying mechanism is not yet fully understood. Hence, we aim to investigate the impacts of BF on the metabolic organs of infants. METHODS: Previous literatures directly studying the influences of BF on offspring's metabolic organs in both animal models and humans were comprehensively reviewed. A microarray dataset of intestinal gene expression comparing infants fed on breastmilk versus formula milk was analyzed. RESULTS: Reanalysis of microarray data showed that BF is associated with enhanced intestinal gluconeogenesis in infants. This resembles observations in other mammalian species showing that BF was also linked to increased gluconeogenesis. CONCLUSIONS: BF is associated with enhanced intestinal gluconeogenesis in infants, which may underpin its metabolic advantages through finetuning metabolic homeostasis. This observation seems to be conserved across species, hinting its biological significance.


Assuntos
Aleitamento Materno , Síndrome Metabólica , Lactente , Feminino , Animais , Humanos , Gluconeogênese , Mamíferos
2.
Genes Cells ; 29(3): 183-191, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38311861

RESUMO

Metformin is an anti-diabetic drug. Metformin mainly inhibits gluconeogenesis in the liver and reduces blood sugar. In addition to the anti-diabetic effects, many studies have revealed that metformin has anti-inflammatory effects. Various molecules were suggested to be the target of the metformin's anti-inflammatory effects. However, the conclusion is not clear. Metformin is related to a number of molecules and the identification of the main target in anti-inflammatory effects leads to the understanding of inflammation and metformin. In this article, I discuss each suggested molecule, involved mechanisms, and their relationship with various diseases.


Assuntos
Diabetes Mellitus Tipo 2 , Metformina , Humanos , Metformina/farmacologia , Metformina/uso terapêutico , Metformina/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Gluconeogênese , Fígado/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios/metabolismo
3.
Am J Physiol Endocrinol Metab ; 326(4): E428-E442, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38324258

RESUMO

Glucagon rapidly and profoundly stimulates hepatic glucose production (HGP), but for reasons that are unclear, this effect normally wanes after a few hours, despite sustained plasma glucagon levels. This study characterized the time course of glucagon-mediated molecular events and their relevance to metabolic flux in the livers of conscious dogs. Glucagon was either infused into the hepato-portal vein at a sixfold basal rate in the presence of somatostatin and basal insulin, or it was maintained at a basal level in control studies. In one control group, glucose remained at basal, whereas in the other, glucose was infused to match the hyperglycemia that occurred in the hyperglucagonemic group. Elevated glucagon caused a rapid (30 min) and largely sustained increase in hepatic cAMP over 4 h, a continued elevation in glucose-6-phosphate (G6P), and activation and deactivation of glycogen phosphorylase and synthase activities, respectively. Net hepatic glycogenolysis increased rapidly, peaking at 15 min due to activation of the cAMP/PKA pathway, then slowly returned to baseline over the next 3 h in line with allosteric inhibition by glucose and G6P. Glucagon's stimulatory effect on HGP was sustained relative to the hyperglycemic control group due to continued PKA activation. Hepatic gluconeogenic flux did not increase due to the lack of glucagon's effect on substrate supply to the liver. Global gene expression profiling highlighted glucagon-regulated activation of genes involved in cellular respiration, metabolic processes, and signaling, as well as downregulation of genes involved in extracellular matrix assembly and development.NEW & NOTEWORTHY Glucagon rapidly stimulates hepatic glucose production, but these effects are transient. This study links the molecular and metabolic flux changes that occur in the liver over time in response to a rise in glucagon, demonstrating the strength of the dog as a translational model to couple findings in small animals and humans. In addition, this study clarifies why the rapid effects of glucagon on liver glycogen metabolism are not sustained.


Assuntos
Glucagon , Insulina , Humanos , Cães , Animais , Glucagon/metabolismo , Insulina/metabolismo , Transcriptoma , Glucose/metabolismo , Fígado/metabolismo , Gluconeogênese/genética , Glicemia/metabolismo
4.
PLoS Negl Trop Dis ; 18(2): e0012007, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38394337

RESUMO

Trypanosoma brucei is a causative agent of the Human and Animal African Trypanosomiases. The mammalian stage parasites infect various tissues and organs including the bloodstream, central nervous system, skin, adipose tissue and lungs. They rely on ATP produced in glycolysis, consuming large amounts of glucose, which is readily available in the mammalian host. In addition to glucose, glycerol can also be used as a source of carbon and ATP and as a substrate for gluconeogenesis. However, the physiological relevance of glycerol-fed gluconeogenesis for the mammalian-infective life cycle forms remains elusive. To demonstrate its (in)dispensability, first we must identify the enzyme(s) of the pathway. Loss of the canonical gluconeogenic enzyme, fructose-1,6-bisphosphatase, does not abolish the process hence at least one other enzyme must participate in gluconeogenesis in trypanosomes. Using a combination of CRISPR/Cas9 gene editing and RNA interference, we generated mutants for four enzymes potentially capable of contributing to gluconeogenesis: fructose-1,6-bisphoshatase, sedoheptulose-1,7-bisphosphatase, phosphofructokinase and transaldolase, alone or in various combinations. Metabolomic analyses revealed that flux through gluconeogenesis was maintained irrespective of which of these genes were lost. Our data render unlikely a previously hypothesised role of a reverse phosphofructokinase reaction in gluconeogenesis and preclude the participation of a novel biochemical pathway involving transaldolase in the process. The sustained metabolic flux in gluconeogenesis in our mutants, including a triple-null strain, indicates the presence of a unique enzyme participating in gluconeogenesis. Additionally, the data provide new insights into gluconeogenesis and the pentose phosphate pathway, and improve the current understanding of carbon metabolism of the mammalian-infective stages of T. brucei.


Assuntos
Gluconeogênese , Trypanosoma brucei brucei , Animais , Humanos , Gluconeogênese/genética , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Transaldolase/metabolismo , Glicerol/metabolismo , Glucose/metabolismo , Fosfofrutoquinases/metabolismo , Carbono/metabolismo , Trifosfato de Adenosina/metabolismo , Mamíferos
5.
Chin Med J (Engl) ; 137(2): 190-199, 2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38184784

RESUMO

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a severe liver disease with complex pathogenesis. Clinical hypoglycemia is common in patients with ACLF and often predicts a worse prognosis. Accumulating evidence suggests that glucose metabolic disturbance, especially gluconeogenesis dysfunction, plays a critical role in the disease progression of ACLF. Lon protease-1 (LONP1) is a novel mediator of energy and glucose metabolism. However, whether gluconeogenesis is a potential mechanism through which LONP1 modulates ACLF remains unknown. METHODS: In this study, we collected liver tissues from ACLF patients, established an ACLF mouse model with carbon tetrachloride (CCl 4 ), lipopolysaccharide (LPS), and D-galactose (D-gal), and constructed an in vitro hypoxia and hyperammonemia-triggered hepatocyte injury model. LONP1 overexpression and knockdown adenovirus were used to assess the protective effect of LONP1 on liver injury and gluconeogenesis regulation. Liver histopathology, biochemical index, mitochondrial morphology, cell viability and apoptosis, and the expression and activity of key gluconeogenic enzymes were detected to explore the underlying protective mechanisms of LONP1 in ACLF. RESULTS: We found that LONP1 and the expressions of gluconeogenic enzymes were downregulated in clinical ACLF liver tissues. Furthermore, LONP1 overexpression remarkably attenuated liver injury, which was characterized by improved liver histopathological lesions and decreased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in ACLF mice. Moreover, mitochondrial morphology was improved upon overexpression of LONP1. Meanwhile, the expression and activity of the key gluconeogenic enzymes were restored by LONP1 overexpression. Similarly, the hepatoprotective effect was also observed in the hepatocyte injury model, as evidenced by improved cell viability, reduced cell apoptosis, and improved gluconeogenesis level and activity, while LONP1 knockdown worsened liver injury and gluconeogenesis disorders. CONCLUSION: We demonstrated that gluconeogenesis dysfunction exists in ACLF, and LONP1 could ameliorate liver injury and improve gluconeogenic dysfunction, which would provide a promising therapeutic target for patients with ACLF.


Assuntos
Insuficiência Hepática Crônica Agudizada , Protease La , Animais , Humanos , Camundongos , Insuficiência Hepática Crônica Agudizada/patologia , Proteases Dependentes de ATP/metabolismo , Gluconeogênese , Hepatócitos/patologia , Fígado/metabolismo , Proteínas Mitocondriais/metabolismo , Protease La/metabolismo
6.
Metabolism ; 152: 155772, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38176644

RESUMO

INTRODUCTION: The levels of the cellular energy sensor AMP-activated protein kinase (AMPK) have been reported to be decreased via unknown mechanisms in the liver of mice deficient in growth differentiation factor 15 (GDF15). This stress response cytokine regulates energy metabolism mainly by reducing food intake through its hindbrain receptor GFRAL. OBJECTIVE: To examine how GDF15 regulates AMPK. METHODS: Wild-type and Gdf15-/- mice, mouse primary hepatocytes and the human hepatic cell line Huh-7 were used. RESULTS: Gdf15-/- mice showed glucose intolerance, reduced hepatic phosphorylated AMPK levels, increased levels of phosphorylated mothers against decapentaplegic homolog 3 (SMAD3; a mediator of the fibrotic response), elevated serum levels of transforming growth factor (TGF)-ß1, as well as upregulated gluconeogenesis and fibrosis. In line with these observations, recombinant (r)GDF15 promoted AMPK activation and reduced the levels of phosphorylated SMAD3 and the markers of gluconeogenesis and fibrosis in the liver of mice and in mouse primary hepatocytes, suggesting that these effects may be independent of GFRAL. Pharmacological inhibition of SMAD3 phosphorylation in Gdf15-/- mice prevented glucose intolerance, the deactivation of AMPK and the increase in the levels of proteins involved in gluconeogenesis and fibrosis, suggesting that overactivation of the TGF-ß1/SMAD3 pathway is responsible for the metabolic alterations in Gdf15-/- mice. CONCLUSIONS: Overall, these findings indicate that GDF15 activates AMPK and inhibits gluconeogenesis and fibrosis by lowering the activity of the TGF-ß1/SMAD3 pathway.


Assuntos
Intolerância à Glucose , Fator de Crescimento Transformador beta1 , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Fibrose , Gluconeogênese , Intolerância à Glucose/metabolismo , Fator 15 de Diferenciação de Crescimento/genética , Fígado/metabolismo , Transdução de Sinais , Proteína Smad3 , Fator de Crescimento Transformador beta1/metabolismo
7.
Int J Biol Macromol ; 260(Pt 1): 129491, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38228202

RESUMO

In this study, the impact of prenatal exposure to Epigallocatechin gallate (EGCG) on the liver of adult offspring mice was investigated. While EGCG is known for its health benefits, its effects of prenatal exposure on the liver remain unclear. Pregnant C57BL/6 J mice were exposed to 1 mg/kg of EGCG for 16 days to assess hepatotoxicity effects of adult offspring. Transcriptomics and metabolomics were employed to elucidate the hepatotoxicity mechanisms. The findings revealed that prenatal EGCG exposure led to a decrease in liver somatic index, enhanced inflammatory responses and disrupted liver function through increased glycogen accumulation in adult mice. The integrated omics analysis revealed significant alterations in key pathways involved in liver glucose lipid metabolism, such as gluconeogenesis, dysregulation of insulin signaling, and induction of liver inflammation. Furthermore, the study found a negative correlation between the promoter methylation levels of Ppara and their mRNA levels, suggesting that EGCG could reduce hepatic lipid content through epigenetic modifications. The findings suggest that prenatal EGCG exposure can have detrimental impacts on the liver among adult individuals and emphasize the need for a comprehensive evaluation of the potential risks associated with EGCG consumption during pregnancy.


Assuntos
Catequina , Catequina/análogos & derivados , Doença Hepática Induzida por Substâncias e Drogas , Efeitos Tardios da Exposição Pré-Natal , Humanos , Gravidez , Feminino , Camundongos , Animais , Glicogênio Hepático/metabolismo , Glicogênio Hepático/farmacologia , Metabolismo dos Lipídeos , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Camundongos Endogâmicos C57BL , Fígado , Catequina/farmacologia , Catequina/metabolismo , Gluconeogênese , Doença Hepática Induzida por Substâncias e Drogas/metabolismo
8.
Life Sci ; 339: 122432, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38237764

RESUMO

AIMS: Anti-diabetic and anti-obesity effects of L-citrulline (Cit) have been reported in male rats. This study determined sex differences in response to Cit in Wistar rats. MAIN METHODS: Type 2 diabetes (T2D) was induced using a high-fat diet followed by low-dose of streptozotocin (30 mg/kg) injection. Male and female Wistar rats were divided into 4 groups (n = 6/group): Control, control+Cit, T2D, and T2D + Cit. Cit (4 g/L in drinking water) was administered for 8 weeks. Obesity indices were recorded, serum fasting glucose and lipid profile were measured, and glucose and pyruvate tolerance tests were performed during the Cit intervention. White (WAT) and brown (BAT) adipose tissues were weighted, and the adiposity index was calculated at the end of the study. KEY FINDINGS: Cit was more effective in decreasing fasting glucose (18 % vs. 11 %, P = 0.0100), triglyceride (20 % vs. 14 %, P = 0.0173), and total cholesterol (16 % vs. 11 %, P = 0.0200) as well as decreasing gluconeogenesis and improving glucose tolerance, in females compared to male rats with T2D. Following Cit administration, decreases in WAT weight (16 % vs. 14 % for gonadal, 21 % vs. 16 % for inguinal, and 18 % vs. 13 % for retroperitoneal weight, all P < 0.0001) and increases in BAT weight (58 % vs. 19 %, for interscapular and 10 % vs. 7 % for axillary, all P < 0.0001) were higher in females than male rats with T2D. The decrease in adiposity index was also higher (11 % vs. 9 %, P = 0.0007) in females. SIGNIFICANCE: The anti-obesity and anti-diabetic effects of Cit in rats are sex-dependent, with Cit being more effective in female than male rats.


Assuntos
Citrulina , Diabetes Mellitus Tipo 2 , Ratos , Feminino , Masculino , Animais , Ratos Wistar , Citrulina/farmacologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Obesidade/tratamento farmacológico , Glucose , Gluconeogênese
9.
PLoS Genet ; 20(1): e1011115, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38227606

RESUMO

Timely regulation of carbon metabolic pathways is essential for cellular processes and to prevent futile cycling of intracellular metabolites. In Halobacterium salinarum, a hypersaline adapted archaeon, a sugar-sensing TrmB family protein controls gluconeogenesis and other biosynthetic pathways. Notably, Hbt. salinarum does not utilize carbohydrates for energy, uncommon among Haloarchaea. We characterized a TrmB-family transcriptional regulator in a saccharolytic generalist, Haloarcula hispanica, to investigate whether the targets and function of TrmB, or its regulon, is conserved in related species with distinct metabolic capabilities. In Har. hispanica, TrmB binds to 15 sites in the genome and induces the expression of genes primarily involved in gluconeogenesis and tryptophan biosynthesis. An important regulatory control point in Hbt. salinarum, activation of ppsA and repression of pykA, is absent in Har. hispanica. Contrary to its role in Hbt. salinarum and saccharolytic hyperthermophiles, TrmB does not act as a global regulator: it does not directly repress the expression of glycolytic enzymes, peripheral pathways such as cofactor biosynthesis, or catabolism of other carbon sources in Har. hispanica. Cumulatively, these findings suggest rewiring of the TrmB regulon alongside metabolic network evolution in Haloarchaea.


Assuntos
Gluconeogênese , Fatores de Transcrição , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Gluconeogênese/genética , Archaea/genética , Regulação da Expressão Gênica em Archaea , Carboidratos , Carbono/metabolismo
10.
Endocrinol Metab (Seoul) ; 39(1): 98-108, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38171209

RESUMO

BACKGRUOUND: Sodium-dependent glucose cotransporter 2 (SGLT2) mediates glucose reabsorption in the renal proximal tubules, and SGLT2 inhibitors are used as therapeutic agents for treating type 2 diabetes mellitus. This study aimed to elucidate the effects and mechanisms of SGLT2 inhibition on hepatic glucose metabolism in both serum deprivation and serum supplementation states. METHODS: Huh7 cells were treated with the SGLT2 inhibitors empagliflozin and dapagliflozin to examine the effect of SGLT2 on hepatic glucose uptake. To examine the modulation of glucose metabolism by SGLT2 inhibition under serum deprivation and serum supplementation conditions, HepG2 cells were transfected with SGLT2 small interfering RNA (siRNA), cultured in serum-free Dulbecco's modified Eagle's medium for 16 hours, and then cultured in media supplemented with or without 10% fetal bovine serum for 8 hours. RESULTS: SGLT2 inhibitors dose-dependently decreased hepatic glucose uptake. Serum deprivation increased the expression levels of the gluconeogenesis genes peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), glucose 6-phosphatase (G6pase), and phosphoenolpyruvate carboxykinase (PEPCK), and their expression levels during serum deprivation were further increased in cells transfected with SGLT2 siRNA. SGLT2 inhibition by siRNA during serum deprivation induces nuclear localization of the transcription factor forkhead box class O 1 (FOXO1), decreases nuclear phosphorylated-AKT (p-AKT), and p-FOXO1 protein expression, and increases phosphorylated-adenosine monophosphate-activated protein kinase (p-AMPK) protein expression. However, treatment with the AMPK inhibitor, compound C, reversed the reduction in the protein expression levels of nuclear p- AKT and p-FOXO1 and decreased the protein expression levels of p-AMPK and PEPCK in cells transfected with SGLT2 siRNA during serum deprivation. CONCLUSION: These data show that SGLT2 mediates glucose uptake in hepatocytes and that SGLT2 inhibition during serum deprivation increases gluconeogenesis via the AMPK/AKT/FOXO1 signaling pathway.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Gluconeogênese/genética , Glucose , Fosfoenolpiruvato Carboxiquinase (ATP)/genética , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/farmacologia , Proteínas Proto-Oncogênicas c-akt/uso terapêutico , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/farmacologia , Transdução de Sinais , Sódio/metabolismo , Sódio/farmacologia , Sódio/uso terapêutico , Transportador 2 de Glucose-Sódio/metabolismo , Transportador 2 de Glucose-Sódio/farmacologia , Transportador 2 de Glucose-Sódio/uso terapêutico , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
11.
Adv Sci (Weinh) ; 11(4): e2302325, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38059818

RESUMO

Omega-6 fatty acids are the primary polyunsaturated fatty acids in most Western diets, while their role in diabetes remains controversial. Exposure of omega-6 fatty acids to an oxidative environment results in the generation of a highly reactive carbonyl species known as trans, trans-2,4-decadienal (tt-DDE). The timely and efficient detoxification of this metabolite, which has actions comparable to other reactive carbonyl species, such as 4-hydroxynonenal, acrolein, acetaldehyde, and methylglyoxal, is essential for disease prevention. However, the detoxification mechanism for tt-DDE remains elusive. In this study, the enzyme Aldh9a1b is identified as having a key role in the detoxification of tt-DDE. Loss of Aldh9a1b increased tt-DDE levels and resulted in an abnormal retinal vasculature and glucose intolerance in aldh9a1b-/- zebrafish. Transcriptomic and metabolomic analyses revealed that tt-DDE and aldh9a1b deficiency in larval and adult zebrafish induced insulin resistance and impaired glucose homeostasis. Moreover, alterations in hyaloid vasculature is induced by aldh9a1b knockout or by tt-DDE treatment can be rescued by the insulin receptor sensitizers metformin and rosiglitazone. Collectively, these results demonstrated that tt-DDE is the substrate of Aldh9a1b which causes microvascular damage and impaired glucose metabolism through insulin resistance.


Assuntos
Aldeídos , Resistência à Insulina , Insulina , Animais , Peixe-Zebra , Gluconeogênese , Ácidos Graxos Ômega-6
13.
Can J Physiol Pharmacol ; 102(1): 33-41, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37944129

RESUMO

Lipopolysaccharide (LPS) results in a lethal hypoglycemic response. However, the main molecular mechanism involved in LPS-induced glucose metabolism disorder is poorly understood. This study intends to investigate the signaling pathways involved in LPS-induced hypoglycemia and potential efficacy of extracellular signal-regulated kinase (ERK) inhibitor SCH772984. The effects of LPS and SCH772984 on gluconeogenesis, glucose absorption, and glycogenolysis were evaluated by pyruvate tolerance test, oral glucose tolerance test, and glucagon test, respectively. After a single intraperitoneal injection of 0.5 mg/kg LPS, the mice's blood glucose levels and gluconeogenesis ability were significantly lower than that of control group. Besides, mRNA and protein expression of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) decreased significantly after LPS treatment. LPS induced the phosphorylation of ERK1/2, MEK1/2 (mitogen-activated protein kinase), and Foxo1 while inhibited Foxo1 expression in the nucleus, indicating an important role of the MEK/ERK/Foxo1 signaling in the inhibition of gluconeogenesis by LPS. Furthermore, SCH772984 elevated blood glucose, increased the G6Pase and PEPCK expression, and inhibited pERK1/2 and pFoxo1 expression in LPS-induced mice. In summary, LPS inhibited gluconeogenesis and induced hypoglycemia through the MEK/ERK/Foxo1 signal pathway, and ERK inhibitor could effectively reverse decreased blood glucose in mice with LPS treatment. These findings provide a novel therapeutic target for LPS-induced hypoglycemia.


Assuntos
Gluconeogênese , Hipoglicemia , Camundongos , Animais , Glicemia/metabolismo , Lipopolissacarídeos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fígado , Glucose/metabolismo , Hipoglicemia/induzido quimicamente , Hipoglicemia/tratamento farmacológico , Hipoglicemia/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Camundongos Endogâmicos C57BL , Proteína Forkhead Box O1/metabolismo , Proteína Forkhead Box O1/farmacologia
14.
Can J Physiol Pharmacol ; 102(1): 42-54, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37523769

RESUMO

The beneficial effects of high-fat low-carbohydrate (HFLC) diets on glucose metabolism have been questioned and their effects on liver metabolism are not totally clear. The aim of this work was to investigate the effects of an HFLC diet under different energy conditions on glucose homeostasis, fatty liver development, and hepatic gluconeogenesis using the isolated perfused rat liver. HFLC diet (79% fat, 19% protein, and 2% carbohydrates in Kcal%) was administered to rats for 4 weeks under three conditions: ad libitum (hypercaloric), isocaloric, and hypocaloric (energy reduction of 20%). Fasting blood glucose levels and total fat in the liver were higher in all HFLC diet rats. Oral glucose tolerance was impaired in isocaloric and hypercaloric groups, although insulin sensitivity was not altered. HFLC diet also caused marked liver metabolic alterations: higher gluconeogenesis rate from lactate and a reduced capacity to metabolize alanine, the latter effect being more intense in the hypocaloric condition. Thus, even when HFLC diets are used for weight loss, our data imply that they can potentially cause harmful consequences for the liver.


Assuntos
Gorduras na Dieta , Fígado Gorduroso , Ratos , Animais , Gluconeogênese , Carboidratos da Dieta/efeitos adversos , Dieta com Restrição de Carboidratos , Fígado/metabolismo , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/metabolismo , Glicemia/metabolismo , Homeostase , Glucose/metabolismo
15.
Redox Biol ; 69: 102989, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38100882

RESUMO

Inspite of exerting independent cellular functions, the endoplasmic-reticulum (ER) and the mitochondria also physically connect at specific sites termed mitochondria-associated ER membranes (MAMs) and these sites consist of several tethering proteins that play varied roles in diverse cellular processes. However, the regulation of these tethering proteins within the cell is relatively less studied. Here, we show that several MAM proteins are significantly altered in the liver during diabetes and among these, the lncRNA, H19 regulates the levels of VDAC1. Inhibition of H19 expression using H19 specific siRNA altered VDAC1, mitochondrial Ca2+ and oxygen consumption rate, ATP and ROS levels and enhanced ER and mitochondria coupling in Hepa 1-6 cells. While H19 inhibition did not impact lipid accumulation, levels of gluconeogenic genes were significantly increased. JNK-phosphorylation and IRS1-Ser307-phosphorylation were increased by H19 inhibition and this was associated with abrogation of insulin-stimulated AKT (Ser-473) phosphorylation and glucose uptake in Hepa 1-6 cells. While inhibition of VDAC1 expression using siRNAs and with metformin significantly rescued the effects of H19 inhibition, VDAC1 overexpression alone exerted effects similar to H19 inhibition, suggesting that VDAC1 increase mediates the adverse effects of H19. In-vivo H19 inhibition using specific siRNAs increased hepatic VDAC1, pJNK and pIRS1 (Ser307) levels and decreased AKT (Ser-473) phosphorylation in mice. These suggest an important role of the H19-VDAC1 axis in ER-mitochondria coupling and regulation of gluconeogenesis in the liver during diabetes.


Assuntos
Diabetes Mellitus , RNA Longo não Codificante , Animais , Camundongos , Diabetes Mellitus/metabolismo , Gluconeogênese , Hepatócitos/metabolismo , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Longo não Codificante/genética
16.
Metabolism ; 152: 155766, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38145825

RESUMO

BACKGROUND: Excessive hepatic glucose production is a hallmark that contributes to hyperglycemia in type 2 diabetes (T2D). The regulatory network governing this process remains incompletely understood. Here, we demonstrate that TOX3, a high-mobility group family member, acts as a major transcriptional driver for hepatic glucose production. METHODS: Tox3-overexpressed and knockout mice were constructed to explore its metabolic functions. Transcriptomic and chromatin-immunoprecipitation sequencing (ChIP-seq) were used to identify downstream targets of TOX3. Both FoxO1 silencing and inhibitor approaches were used to assess the contribution of FoxO1. TOX3 expression levels were examined in the livers of mice and human subjects. Finally, Tox3 was genetically manipulated in diet-induced obese mice to evaluate its therapeutic potential. RESULTS: Hepatic Tox3 overexpression activates the gluconeogenic program, resulting in hyperglycemia and insulin resistance in mice. Hepatocyte-specific Tox3 knockout suppresses gluconeogenesis and improves insulin sensitivity. Mechanistically, integrated hepatic transcriptomic and ChIP-seq analyses identify FoxO1 as a direct target of TOX3. TOX3 stimulates FoxO1 transcription by directly binding to and activating its promoter, whereas FoxO1 silencing abrogates TOX3-induced dysglycemia in mice. In human subjects, hepatic TOX3 expression shows a significant positive correlation with blood glucose levels under normoglycemic conditions, yet is repressed by high glucose during T2D. Importantly, hepatic Tox3 deficiency markedly protects against and ameliorates the hyperglycemia and glucose intolerance in diet-induced diabetic mice. CONCLUSIONS: Our findings establish TOX3 as a driver for excessive gluconeogenesis through activating hepatic FoxO1 transcription. TOX3 could serve as a promising target for preventing and treating hyperglycemia in T2D.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Hiperglicemia , Resistência à Insulina , Animais , Humanos , Camundongos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Gluconeogênese/genética , Glucose/metabolismo , Hiperglicemia/genética , Hiperglicemia/metabolismo , Fígado/metabolismo , Camundongos Endogâmicos C57BL
17.
Int J Mol Sci ; 24(21)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37958545

RESUMO

Drug-induced liver injury (DILI) is a widespread and harmful disease, and is closely linked to acute endoplasmic reticulum (ER) stress. Previous reports have shown that acute ER stress can suppress hepatic gluconeogenesis and even leads to hypoglycemia. However, the mechanism is still unclear. MAPK phosphatase 3 (MKP-3) is a positive regulator for gluconeogenesis. Thus, this study was conducted to investigate the role of MKP-3 in the suppression of gluconeogenesis by acute ER stress, as well as the regulatory role of acute ER stress on the expression of MKP-3. Results showed that acute ER stress induced by tunicamycin significantly suppressed gluconeogenesis in both hepatocytes and mouse liver, reduced glucose production level in hepatocytes, and decreased fasting blood glucose level in mice. Additionally, the protein level of MKP-3 was reduced by acute ER stress in both hepatocytes and mouse liver. Mkp-3 deficiency eliminated the inhibitory effect of acute ER stress on gluconeogenesis in hepatocytes. Moreover, the reduction effect of acute ER stress on blood glucose level and hepatic glucose 6-phosphatase (G6pc) expression was not observed in the liver-specific Mkp-3 knockout mice. Furthermore, activation of protein kinase R-like ER kinase (PERK) decreased the MKP-3 protein level, while inactivation of PERK abolished the reduction effect of acute ER stress on the MKP-3 protein level in hepatocytes. Taken together, our study suggested that acute ER stress could suppress hepatic gluconeogenesis by stimulating MKP-3 degradation via PERK, at least partially. Thus, MKP-3 might be a therapeutic target for DILI-related hypoglycemia.


Assuntos
Fosfatase 6 de Especificidade Dupla , Gluconeogênese , Hipoglicemia , Animais , Camundongos , Glicemia/metabolismo , Estresse do Retículo Endoplasmático , Hepatócitos/metabolismo , Hipoglicemia/metabolismo , Fígado/metabolismo , Camundongos Knockout , Fosfatases da Proteína Quinase Ativada por Mitógeno/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Fosfatase 6 de Especificidade Dupla/metabolismo
18.
Int J Mol Sci ; 24(19)2023 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-37834051

RESUMO

The prevalence of hypothyroidism in patients with nonalcoholic fatty liver disease (NAFLD) is high (22.4%). Thyroid hormones (THs) regulate many metabolic activities in the liver by promoting the export and oxidation of lipids, as well as de novo lipogenesis. They also control hepatic insulin sensitivity and suppress hepatic gluconeogenesis. Because of its importance in lipid and carbohydrate metabolism, the involvement of thyroid dysfunction in the pathogenesis of NAFLD seems plausible. The mechanisms implicated in this relationship include high thyroid-stimulating hormone (TSH) levels, low TH levels, and chronic inflammation. The activity of the TH receptor (THR)-ß in response to THs is essential in the pathogenesis of hypothyroidism-induced NAFLD. Therefore, an orally active selective liver THR-ß agonist, Resmetirom (MGL-3196), was developed, and has been shown to reduce liver fat content, and as a secondary end point, to improve nonalcoholic steatohepatitis. The treatment of NAFLD with THR-ß agonists seems quite promising, and other agonists are currently under development and investigation. This review aims to shine a light on the pathophysiological and epidemiological evidence regarding this relationship and the effect that treatment with THs and selective liver THR-ß agonists have on hepatic lipid metabolism.


Assuntos
Hipotireoidismo , Hepatopatia Gordurosa não Alcoólica , Doenças da Glândula Tireoide , Humanos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fígado/metabolismo , Doenças da Glândula Tireoide/patologia , Hormônios Tireóideos/metabolismo , Hipotireoidismo/complicações , Gluconeogênese
19.
World J Gastroenterol ; 29(39): 5471-5482, 2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37900993

RESUMO

BACKGROUND: The small intestine is known to play a crucial role in the development and remission of diabetes mellitus (DM). However, the exact mechanism by which mid-small intestinal bypass improves glucose metabolism in diabetic rats is not fully understood. AIM: To elucidate the mechanisms by which mid-small intestinal bypass improves glucose metabolism. METHODS: Streptozotocin (STZ) was used to induce DM in Sprague-Dawley (SD) rats at a dose of 60 mg/kg. The rats were then randomly divided into two groups: The mid-small intestine bypass (MSIB) group and the sham group (underwent switch laparotomy). Following a 6-wk recovery period post-surgery, the rats underwent various assessments, including metabolic parameter testing, analysis of liver glycogen levels, measurement of key gluconeogenic enzyme activity, characterization of the gut microbiota composition, evaluation of hormone levels, determination of bile acid concentrations, and assessment of the expression of the intestinal receptors Takeda G protein-coupled receptor 5 and farnesoid X receptor. RESULTS: The MSIB group of rats demonstrated improved glucose metabolism and lipid metabolism, along with increased hepatic glycogen content. Furthermore, there was a decrease in the expression of the key gluconeogenic enzymes phosphoenolpyruvate carboxykinase 1 and glucose-6-phosphatase. Importantly, the MSIB group exhibited a substantial increase in the abundances of intestinal Lactobacillus, Clostridium symbiosum, Ruminococcus gnavus, and Bilophila. Moreover, higher levels of secondary bile acids, such as intestinal lithocholic acid, were observed in this group. Remarkably, the changes in the gut microbiota showed a significant correlation with the expression of key gluconeogenic enzymes and glucagon-like peptide 1 (GLP-1) at 6 wk postoperatively, highlighting their potential role in glucose regulation. These findings highlight the beneficial effects of mid-small intestine bypass on glucose metabolism and the associated modulation of the gut microbiota. CONCLUSION: The findings of this study demonstrate that the introduction of postoperative intestinal Clostridium symbiosum in the mid-small intestine contributes to the enhancement of glucose metabolism in nonobese diabetic rats. This improvement is attributed to the increased inhibition of hepatic gluconeogenesis mediated by GLP-1, resulting in a favorable modulation of glucose homeostasis.


Assuntos
Clostridium symbiosum , Diabetes Mellitus Experimental , Derivação Gástrica , Ratos , Animais , Gluconeogênese/fisiologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Clostridium symbiosum/metabolismo , Derivação Jejunoileal , Diabetes Mellitus Experimental/cirurgia , Ratos Sprague-Dawley , Glucose/metabolismo , Homeostase , Glicemia/metabolismo
20.
Front Immunol ; 14: 1232390, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37881434

RESUMO

Background: This study aimed to examine glycolysis/gluconeogenesis-related genes in hepatocellular carcinoma (HCC) and evaluate their potential roles in HCC progression and immunotherapy response. Methods: Data analyzed in this study were collected from GSE14520, GSE76427, GSE174570, The Cancer Genome Atlas (TCGA), PXD006512, and GSE149614 datasets, metabolic pathways were collected from MSigDB database. Differentially expressed genes (DEGs) were identified between HCC and controls. Differentially expressed glycolysis/gluconeogenesis-related genes (candidate genes) were obtained and consensus clustering was performed based on the expression of candidate genes. Bioinformatics analysis was used to evaluate candidate genes and screen prognostic genes. Finally, the key results were tested in HCC patients. Results: Thirteen differentially expressed glycolysis/gluconeogenesis-related genes were validated in additional datasets. Consensus clustering analysis identified two distinct patient clusters (C1 and C2) with different prognoses and immune microenvironments. Immune score and tumor purity were significantly higher in C1 than in C2, and CD4+ memory activated T cell, Tfh, Tregs, and macrophage M0 were higher infiltrated in HCC and C1 group. The study also identified five intersecting DEGs from candidate genes in TCGA, GSE14520, and GSE141198 as prognostic genes, which had a protective role in HCC patient prognosis. Compared with the control group, the prognostic genes all showed decreased expression in HCC patients in RT-qPCR and Western blot analyses. Flow cytometry verified the abnormal infiltration level of immune cells in HCC patients. Conclusion: Results showed that glycolysis/gluconeogenesis-related genes were associated with patient prognosis, immune microenvironment, and response to immunotherapy in HCC. It suggests that the model based on five prognostic genes may valuable for predicting the prognosis and immunotherapy response of HCC patients.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Gluconeogênese , Prognóstico , Neoplasias Hepáticas/genética , Glicólise/genética , Microambiente Tumoral/genética
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