109 results on '"Ruas, Jorge L."'
Search Results
102. Transcriptional control of energy metabolism: studies on FXR and PGC-1á
- Author
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Correia, Jorge Miguel Pratas Camacho, Ribeiro, Vera, and Ruas, Jorge L.
- Subjects
Metabolismo ,Insulina ,Diabetes ,Energia ,Resistência ,Ciências Naturais::Ciências Biológicas [Domínio/Área Científica] ,Ciências biológicas ,Exercícios - Abstract
Tese de doutoramento, Ciências Biológicas, Faculdade de Ciências e Tenologia, Universidade do Algarve, 2014 Sedentary lifestyles, combined with an environment of caloric abundance, have led to a remarkable increase in the incidence of obesity and diabetes. The resistance to insulin action observed in type 2 diabetes is a complex and multifactorial metabolic disorder. Several factors have been implicated in the development of insulin resistance, including systemic low-grade inflammation and ectopic lipid accumulation. The transcriptional regulators FXR and PGC-1α have been shown to promote beneficial effects on energy metabolism, which can be explored to improve metabolic status in settings of insulin resistance. Here, we show that FXR regulates hepatic metabolism in an isoform-dependent manner. Expression of each human FXR variant in primary hepatocytes promoted robust and discrete changes in target gene expression. Importantly, expression of FXRα2 and FXRα4 decreased hepatocyte lipid accumulation and improved insulin sensitivity. Furthermore, FXRα2 expression increased fatty acid oxidation and β-hydroxybutyrate production. In line with these observations, we observed that FXR splicing was dynamically regulated in mouse liver in response to fasting and physical exercise, with an increase in the relative expression of FXRα2. In addition, FXR expression is elevated in white adipose tissue of skeletal muscle-specific PGC-1α1 transgenic mice (MCK-PGC-1α1) and regulates adipocyte expression of major lipolytic mediators. Finally, we show that PGC-1α1 promotes an anti-inflammatory biological response in skeletal muscle, repressing the classical NFκB pathway. MCK-PGC-1α1 mice have decreased IKKβ, p50 and p65 expression, which is accompanied by a strong increase in IκBα protein levels. Importantly, PGC-1α1 enhances insulin-stimulated glycogen synthesis in cultured myotubes upon pro-inflammatory stimulation. Taken together, our results suggest that FXRα2 and PGC-1α1 improve metabolic conditions implicated in the development of insulin resistance and therefore are attractive therapeutic targets for the treatment of obesityassociated metabolic disorders. O sedentarismo e o elevado consumo calórico têm conduzido a um aumento alarmante na incidência de obesidade e diabetes. A resistência à acção da insulina, que ocorre em diabetes tipo 2, é uma anomalia metabólica complexa e multifactorial. Vários factores estão associados ao desenvolvimento de resitência à insulina, incluindo inflamação sistémica e acumulação ectópica de lípidos. Os reguladores transcricionais FXR e PGC-1α promovem efeitos benéficos ao nível do metabolismo energético, que podem ser explorados para melhorar a condição metabólica em estados de resitência à insulina. Nestes estudos, demonstramos que a regulação exercida pelo FXR ao nível do metabolismo lipídico em hepatócitos depende da isoforma expressa. A expressão de cada isoforma do FXR em hepatócitos primários promove alterações distintas na expressão de genes alvo. A expressão de FXRα2 ou FXRα4 diminui a acumulação lipídica em hepatócitos, o que resulta num aumento da sensibilidade à insulina. Ademais, a expressão de FXRα2 promove a oxidação de ácidos gordos e produção de β-hidroxibutirato. Em linha com estas observações, o splicing do FXR é alterado em situações de jejum e exercício físico, com um aumento da expressão relativa de FXRα2. Também observámos que a expressão do FXR se encontra elevada no tecido adiposo de ratinhos com expressão transgénica de PGC-1α1 especificamente no músculo esquelético (MCK-PGC-1α1), participando na regulação de importantes fatores lipolíticos. Finalmente, PGC-1α1 promove uma resposta anti-inflamatória em músculo esquelético, caracterizada por um decréscimo na expressão de IKKβ, p50 e p65 e por um aumento dos níveis proteicos de IκBα, o que sugere um decréscimo significativo na atividade do sistema NFκB. Estas alterações resultam num aumento de sensibilidade à insulina em miotubos submetidos a estímulos pro-inflamatórios. Estes resultados sugerem que FXRα2 e PGC-1α1 promovem melhorias em condições metabólicas associadas com o desenvolvimento de resistência à insulina, sendo portanto alvos terapêuticos interessantes para o tratamento de doenças metabólicas associadas à obesidade. Fundação Para a Ciência e Tecnologia (FCT): SFRH/BD/44825/2008
- Published
- 2014
103. Zfp697 is an RNA-binding protein that regulates skeletal muscle inflammation and remodeling.
- Author
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Correia JC, Jannig PR, Gosztyla ML, Cervenka I, Ducommun S, Præstholm SM, Dias JM, Dumont KD, Liu Z, Liang Q, Edsgärd D, Emanuelsson O, Gregorevic P, Westerblad H, Venckunas T, Brazaitis M, Kamandulis S, Lanner JT, Teixeira AI, Yeo GW, and Ruas JL
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- Animals, Mice, Humans, Inflammation metabolism, Inflammation pathology, Inflammation genetics, Mice, Knockout, Muscular Atrophy metabolism, Muscular Atrophy genetics, Muscular Atrophy pathology, MicroRNAs genetics, MicroRNAs metabolism, Mice, Inbred C57BL, Interferon-gamma metabolism, Muscle, Skeletal metabolism, Muscle, Skeletal pathology, RNA-Binding Proteins metabolism, RNA-Binding Proteins genetics
- Abstract
Skeletal muscle atrophy is a morbidity and mortality risk factor that happens with disuse, chronic disease, and aging. The tissue remodeling that happens during recovery from atrophy or injury involves changes in different cell types such as muscle fibers, and satellite and immune cells. Here, we show that the previously uncharacterized gene and protein Zfp697 is a damage-induced regulator of muscle remodeling. Zfp697/ZNF697 expression is transiently elevated during recovery from muscle atrophy or injury in mice and humans. Sustained Zfp697 expression in mouse muscle leads to a gene expression signature of chemokine secretion, immune cell recruitment, and extracellular matrix remodeling. Notably, although Zfp697 is expressed in several cell types in skeletal muscle, myofiber-specific Zfp697 genetic ablation in mice is sufficient to hinder the inflammatory and regenerative response to muscle injury, compromising functional recovery. We show that Zfp697 is an essential mediator of the interferon gamma response in muscle cells and that it functions primarily as an RNA-interacting protein, with a very high number of miRNA targets. This work identifies Zfp697 as an integrator of cell-cell communication necessary for tissue remodeling and regeneration., Competing Interests: Competing interests statement:G.W.Y. is an Scientific Advisory Board (SAB) member of Jumpcode Genomics and a co-founder, member of the Board of Directors, on the SAB, equity holder, and paid consultant for Locanabio and Eclipse BioInnovations. G.W.Y. is a distinguished visiting professor at the National University of Singapore. G.W.Y.’s interests have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies.
- Published
- 2024
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104. Multivalent insulin receptor activation using insulin-DNA origami nanostructures.
- Author
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Spratt J, Dias JM, Kolonelou C, Kiriako G, Engström E, Petrova E, Karampelias C, Cervenka I, Papanicolaou N, Lentini A, Reinius B, Andersson O, Ambrosetti E, Ruas JL, and Teixeira AI
- Subjects
- Animals, Diabetes Mellitus drug therapy, Insulin, Zebrafish, DNA chemistry, Nanostructures chemistry, Receptor, Insulin drug effects, Receptor, Insulin metabolism
- Abstract
Insulin binds the insulin receptor (IR) and regulates anabolic processes in target tissues. Impaired IR signalling is associated with multiple diseases, including diabetes, cancer and neurodegenerative disorders. IRs have been reported to form nanoclusters at the cell membrane in several cell types, even in the absence of insulin binding. Here we exploit the nanoscale spatial organization of the IR to achieve controlled multivalent receptor activation. To control insulin nanoscale spatial organization and valency, we developed rod-like insulin-DNA origami nanostructures carrying different numbers of insulin molecules with defined spacings. Increasing the insulin valency per nanostructure markedly extended the residence time of insulin-DNA origami nanostructures at the receptors. Both insulin valency and spacing affected the levels of IR activation in adipocytes. Moreover, the multivalent insulin design associated with the highest levels of IR activation also induced insulin-mediated transcriptional responses more effectively than the corresponding monovalent insulin nanostructures. In an in vivo zebrafish model of diabetes, treatment with multivalent-but not monovalent-insulin nanostructures elicited a reduction in glucose levels. Our results show that the control of insulin multivalency and spatial organization with nanoscale precision modulates the IR responses, independent of the insulin concentration. Therefore, we propose insulin nanoscale organization as a design parameter in developing new insulin therapies., (© 2023. The Author(s).)
- Published
- 2024
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105. Zfp697 is an RNA-binding protein that regulates skeletal muscle inflammation and regeneration.
- Author
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Correia JC, Jannig PR, Gosztyla ML, Cervenka I, Ducommun S, Præstholm SM, Dumont K, Liu Z, Liang Q, Edsgärd D, Emanuelsson O, Gregorevic P, Westerblad H, Venckunas T, Brazaitis M, Kamandulis S, Lanner JT, Yeo GW, and Ruas JL
- Abstract
Muscular atrophy is a mortality risk factor that happens with disuse, chronic disease, and aging. Recovery from atrophy requires changes in several cell types including muscle fibers, and satellite and immune cells. Here we show that Zfp697/ZNF697 is a damage-induced regulator of muscle regeneration, during which its expression is transiently elevated. Conversely, sustained Zfp697 expression in mouse muscle leads to a gene expression signature of chemokine secretion, immune cell recruitment, and extracellular matrix remodeling. Myofiber-specific Zfp697 ablation hinders the inflammatory and regenerative response to muscle injury, compromising functional recovery. We uncover Zfp697 as an essential interferon gamma mediator in muscle cells, interacting primarily with ncRNAs such as the pro-regenerative miR-206. In sum, we identify Zfp697 as an integrator of cell-cell communication necessary for tissue regeneration., Competing Interests: Competing Interests: G.W.Y. is an SAB member of Jumpcode Genomics and a co-founder, member of the Board of Directors, on the SAB, equity holder, and paid consultant for Locanabio and Eclipse BioInnovations. G.W.Y. is a distinguished visiting professor at the National University of Singapore. G.W.Y.’s interests have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies.
- Published
- 2023
- Full Text
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106. Changes in plasma concentration of kynurenine following intake of branched-chain amino acids are not caused by alterations in muscle kynurenine metabolism.
- Author
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Jonsson WO, Ponette J, Horwath O, Rydenstam T, Söderlund K, Ekblom B, Azzolini M, Ruas JL, and Blomstrand E
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- Adult, Female, Humans, Kynurenine metabolism, Male, Oxygen Consumption physiology, Young Adult, Amino Acids, Branched-Chain administration & dosage, Exercise physiology, Kynurenine blood, Muscle, Skeletal drug effects, Muscle, Skeletal metabolism, Oxygen Consumption drug effects
- Abstract
Administration of branched-chain amino acids (BCAA) has been suggested to enhance mitochondrial biogenesis, including levels of PGC-1α, which may, in turn, alter kynurenine metabolism. Ten healthy subjects performed 60 min of dynamic one-leg exercise at ∼70% of W
max on two occasions. They were in random order supplied either a mixture of BCAA or flavored water (placebo) during the experiment. Blood samples were collected during exercise and recovery, and muscle biopsies were taken from both legs before, after, and 90 and 180 min following exercise. Ingestion of BCAA doubled their concentration in both plasma and muscle while causing a 30%-40% reduction ( P < 0.05 vs. placebo) in levels of aromatic amino acids in both resting and exercising muscle during 3-h recovery period. The muscle concentration of kynurenine decreased by 25% ( P < 0.05) during recovery, similar in both resting and exercising leg and with both supplements, although plasma concentration of kynurenine during recovery was 10% lower ( P < 0.05) when BCAA were ingested. Ingestion of BCAA reduced the plasma concentration of kynurenic acid by 60% ( P < 0.01) during exercise and recovery, whereas the level remained unchanged with placebo. Exercise induced a three- to fourfold increase ( P < 0.05) in muscle content of PGC-1α1 mRNA after 90 min of recovery under both conditions, whereas levels of KAT4 mRNA and protein were unaffected by exercise or supplement. In conclusion, the reduction of plasma levels of kynurenine and kynurenic acid caused by BCAA were not associated with any changes in the level of muscle kynurenine, suggesting that kynurenine metabolism was altered in tissues other than muscle.- Published
- 2022
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107. Complex regulation of the transactivation function of hypoxia-inducible factor-1 alpha by direct interaction with two distinct domains of the CREB-binding protein/p300.
- Author
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Ruas JL, Berchner-Pfannschmidt U, Malik S, Gradin K, Fandrey J, Roeder RG, Pereira T, and Poellinger L
- Subjects
- 2,2'-Dipyridyl pharmacology, Cell Line, Chelating Agents pharmacology, Cysteine metabolism, E1A-Associated p300 Protein chemistry, HeLa Cells, Histidine metabolism, Humans, Hypoxia metabolism, Kidney cytology, Mutagenesis, Protein Interaction Domains and Motifs drug effects, Protein Interaction Domains and Motifs physiology, Protein Structure, Tertiary, Transcriptional Activation physiology, Tumor Suppressor Protein p53 metabolism, p300-CBP Transcription Factors chemistry, E1A-Associated p300 Protein metabolism, Hypoxia physiopathology, Hypoxia-Inducible Factor 1, alpha Subunit chemistry, Hypoxia-Inducible Factor 1, alpha Subunit genetics, Hypoxia-Inducible Factor 1, alpha Subunit metabolism, p300-CBP Transcription Factors metabolism
- Abstract
Activation of transcription in response to low oxygen tension is mediated by the hypoxia-inducible factor-1 (HIF-1). HIF-1 is a heterodimer of two proteins: aryl hydrocarbon receptor nuclear translocator and the oxygen-regulated HIF-1 alpha. The C-terminal activation domain of HIF-1 alpha has been shown to interact with cysteine/histidine-rich region 1 (CH1) of the coactivator CBP/p300 in a hypoxia-dependent manner. However, HIF forms lacking C-terminal activation domain (naturally occurring or genetically engineered) are still able to activate transcription of target genes in hypoxia. Here, we demonstrate that the N-terminal activation domain (N-TAD) of HIF-1 alpha interacts with endogenous CBP and that this interaction facilitates its transactivation function. Our results show that interaction of HIF-1 alpha N-TAD with CBP/p300 is mediated by the CH3 region of CBP known to interact with, among other factors, p53. Using fluorescence resonance energy transfer experiments, we demonstrate that N-TAD interacts with CH3 in vivo. Coimmunoprecipitation assays using endogenous proteins showed that immunoprecipitation of CBP in hypoxia results in the recovery of a larger fraction of HIF-1 alpha than of p53. Chromatin immunoprecipitation demonstrated that at 1% O(2) CBP is recruited to a HIF-1 alpha but not to a p53 target gene. Upon activation of both pathways, lower levels of chromatin-associated CBP were detected at either target gene promoter. These results identify CBP as the coactivator directly interacting with HIF-1 alpha N-TAD and mediating the transactivation function of this domain. Thus, we suggest that in hypoxia HIF-1 alpha is a major CBP-interacting transcription factor that may compete with other CBP-dependent factors, including p53, for limiting amounts of this coactivator, underscoring the complexity in the regulation of gene expression by HIF-1 alpha.
- Published
- 2010
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108. Cell-type-specific regulation of degradation of hypoxia-inducible factor 1 alpha: role of subcellular compartmentalization.
- Author
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Zheng X, Ruas JL, Cao R, Salomons FA, Cao Y, Poellinger L, and Pereira T
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- Amino Acid Sequence, Animals, Carcinoma, Hepatocellular metabolism, Cattle, Cell Compartmentation, Cell Hypoxia, Cell Line, Cells, Cultured, Endothelium, Vascular cytology, Endothelium, Vascular metabolism, Gene Products, tat genetics, Gene Products, tat metabolism, Humans, Hypoxia-Inducible Factor 1, alpha Subunit genetics, Mice, Models, Biological, Neovascularization, Physiologic, Peptide Fragments genetics, Peptide Fragments metabolism, Proteasome Endopeptidase Complex metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Subcellular Fractions metabolism, Von Hippel-Lindau Tumor Suppressor Protein metabolism, Hypoxia-Inducible Factor 1, alpha Subunit metabolism
- Abstract
The hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a transcription factor that mediates adaptive cellular responses to decreased oxygen availability (hypoxia). At normoxia, HIF-1 alpha is targeted by the von Hippel-Lindau tumor suppressor protein (pVHL) for degradation by the ubiquitin-proteasome pathway. In the present study we have observed distinct cell-type-specific differences in the ability of various tested pVHL-interacting subfragments to stabilize HIF-1 alpha and unmask its function at normoxia. These properties correlated with differences in subcellular compartmentalization and degradation of HIF-1 alpha. We observed that the absence or presence of nuclear localization or export signals differently affected the ability of a minimal HIF-1 alpha peptide spanning residues 559 to 573 of mouse HIF-1 alpha to stabilize endogenous HIFalpha and induce HIF-driven reporter gene activity in two different cell types (primary mouse endothelial and HepG2 hepatoma cells). Degradation of HIF-1 alpha occurred mainly in the cytoplasm of HepG2 cells, whereas it occurs with equal efficiency in nuclear and cytoplasmic compartments of primary endothelial cells. Consistent with these observations, green fluorescent protein-HIF-1 alpha is differently distributed during hypoxia and reoxygenation in hepatoma and endothelial cells. Consequently, we propose that differential compartmentalization of degradation of HIF-1 alpha and the subcellular distribution of HIF-1 alpha may account for cell-type-specific differences in stabilizing HIF-1 alpha protein levels under hypoxic conditions.
- Published
- 2006
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109. Functional analysis of hypoxia-inducible factor-1 alpha-mediated transactivation. Identification of amino acid residues critical for transcriptional activation and/or interaction with CREB-binding protein.
- Author
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Ruas JL, Poellinger L, and Pereira T
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- Amino Acid Motifs, Amino Acid Sequence, Animals, CREB-Binding Protein, Cell Line, Cell Nucleus metabolism, Histone Acetyltransferases, Humans, Hypoxia-Inducible Factor 1, alpha Subunit, Leucine metabolism, Mice, Molecular Sequence Data, Mutation, Nuclear Receptor Coactivator 1, Protein Binding, Protein Structure, Tertiary, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Transcription Factors genetics, Nuclear Proteins metabolism, Protein Structure, Secondary, Trans-Activators metabolism, Transcription Factors metabolism, Transcriptional Activation physiology
- Abstract
The hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a key regulator of adaptive responses to hypoxia. HIF-1 alpha has two independent transactivation domains (TADs). Whereas the N-terminal TAD (N-TAD) also constitutes a degradation box, the C-terminal TAD (C-TAD) functions in a strictly hypoxia-inducible fashion. Oxygen-dependent hydroxylation of an asparagine residue has recently been reported to regulate C-TAD function by disrupting the interaction with the CH1 domain of the p300/CBP coactivator at normoxia. Here we have performed alanine-scanning mutagenesis of a predicted alpha-helix within the C-TAD of mouse HIF-1 alpha to identify residues important for transactivation and interaction of the C-TAD with transcriptional coactivators. We observed that several hydrophobic residues, Ile(802), Leu(808), Leu(814), Leu(815), and Leu(818), were critical for transactivation and binding to the CH1 domain of CBP in hypoxic cells. Moreover, E812A/E813A and D819A mutations impaired hypoxia-dependent transactivation without disrupting binding to CH1. In the context of full-length HIF-1 alpha, mutation of the leucine residues conferred conformational changes to the protein and significantly reduced the transactivation function as well as functional interaction with the transcriptional coactivators CBP and SRC-1. These mutations also affected intranuclear redistribution of HIF-1 alpha in the presence of CBP, indicating that the integrity of the C-TAD is critical for intracellular localization of mouse HIF-1 alpha.
- Published
- 2002
- Full Text
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