RESUMO
Butyrate is a short-chain fatty acid (SCFA) derived from microbiota and is involved in a range of cell processes in a concentration-dependent manner. Low concentrations of sodium butyrate (NaBu) were shown to be proangiogenic. However, the mechanisms associated with these effects are not yet fully known. Here, we investigated the contribution of the SCFA receptor GPR43 in the proangiogenic effects of local treatment with NaBu and its effects on matrix remodeling using the sponge-induced fibrovascular tissue model in mice lacking the Gpr43 gene (Gpr43-KO) and the wild-type (WT) mice. We demonstrated that NaBu (0.2 mM intraimplant) treatment enhanced the neovascularization process, blood flow, and VEGF levels in a GPR43-dependent manner in the implants. Moreover, NaBu was able to modulate matrix remodeling aspects of the granulation tissue such as proteoglycan production, collagen deposition, and α-smooth muscle actin (α-SMA) expression in vivo, besides increasing transforming growth factor (TGF)-ß1 levels in the fibrovascular tissue, in a GPR43-dependent manner. Interestingly, NaBu directly stimulated L929 murine fibroblast migration and TGF-ß1 and collagen production in vitro. GPR43 was found to be expressed in human dermal fibroblasts, myofibroblasts, and endothelial cells. Overall, our findings evidence that the metabolite-sensing receptor GPR43 contributes to the effects of low dose of NaBu in inducing angiogenesis and matrix remodeling during granulation tissue formation. These data provide important insights for the proposition of new therapeutic approaches based on NaBu, beyond the highly explored intestinal, anti-inflammatory, and anticancer purposes, as a local treatment to improve tissue repair, particularly, by modulating granulation tissue components.NEW & NOTEWORTHY Our data show the contribution of the metabolite-sensing receptor GPR43 in the effects of low dose of sodium butyrate (NaBu) on stimulating angiogenesis and extracellular matrix remodeling in a model of granulation tissue formation in mice. We also show that human dermal fibroblasts, myofibroblasts, and endothelial cells express the receptor GPR43. These data provide important insights for the use of NaBu in local therapeutic approaches applicable to tissue repair in sites other than the intestine.
Assuntos
Indutores da Angiogênese/administração & dosagem , Ácido Butírico/administração & dosagem , Matriz Extracelular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Tecido de Granulação/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Receptores Acoplados a Proteínas G/metabolismo , Animais , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Colágeno/metabolismo , Modelos Animais de Doenças , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Tecido de Granulação/metabolismo , Tecido de Granulação/patologia , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/genética , Tampões de Gaze Cirúrgicos , Fator de Crescimento Transformador beta1/metabolismoRESUMO
In taste buds, glutamate plays a double role as a gustatory stimulus and neuromodulator. The detection of glutamate as a tastant involves several G protein-coupled receptors, including the heterodimer taste receptor type 1, member 1 and 3 as well as metabotropic glutamate receptors (mGluR1 and mGluR4). Both receptor types participate in the detection of glutamate as shown with knockout animals and selective antagonists. At the basal part of taste buds, ionotropic glutamate receptors [N-methyl-d-aspartate (NMDA) and non-NMDA] are expressed and participate in the modulation of the taste signal before its transmission to the brain. Evidence suggests that glutamate has an efferent function on taste cells and modulates the release of other neurotransmitters such as serotonin and ATP. This short article reviews the recent developments in the field with regard to glutamate receptors involved in both functions as well as the influence of glutamate on the taste signal.
Assuntos
Ácido Glutâmico/farmacologia , Neurotransmissores , Papilas Gustativas/efeitos dos fármacos , Paladar/efeitos dos fármacos , Animais , Humanos , Camundongos , Camundongos Knockout , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/fisiologia , Papilas Gustativas/anatomia & histologia , Papilas Gustativas/fisiologiaRESUMO
Herpes simplex virus type 1 (HSV-1) is a human pathogen that may cause severe encephalitis. The exacerbated immune response against the virus contributes to the disease severity and death. Platelet activating factor (PAF) is a mediator capable of inducing increase in vascular permeability, production of cytokines on endothelial cells and leukocytes. We aimed to investigate the activation of PAF receptor (PAFR) and its contribution to the severity of the inflammatory response in the brain following HSV-1 infection. C57BL/6 wild-type (WT) and PAFR deficient (PAFR-/-) mice were inoculated intracranially with 104 plaque-forming units (PFU) of HSV-1. Visualization of leukocyte recruitment was performed using intravital microscopy. Cells infiltration in the brain tissue were analyzed by flow cytometry. Brain was removed for chemokine assessment by ELISA and for histopathological analysis. The pharmacological inhibition by the PAFR antagonist UK-74,505 was also analyzed. In PAFR-/- mice, there was delayed lethality but no difference in viral load. Histopathological analysis of infected PAFR-/- mice showed that brain lesions were less severe when compared to their WT counterparts. Moreover, PAFR-/- mice showed less TCD4+, TCD8+ and macrophages in brain tissue. This reduction of the presence of leukocytes in parenchyma may be mechanistically explained by a decrease in leukocytes rolling and adhesion. PAFR-/- mice also presented a reduction of the chemokine CXCL9 in the brain. In addition, by antagonizing PAFR, survival of C57BL/6 infected mice increased. Altogether, our data suggest that PAFR plays a role in the pathogenesis of experimental HSV-1 meningoencephalitis, and its blockade prevents severe disease manifestation.
Assuntos
Herpes Simples/metabolismo , Herpesvirus Humano 1 , Meningoencefalite/metabolismo , Glicoproteínas da Membrana de Plaquetas/antagonistas & inibidores , Glicoproteínas da Membrana de Plaquetas/deficiência , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/deficiência , Índice de Gravidade de Doença , Animais , Encéfalo/patologia , Encéfalo/virologia , Di-Hidropiridinas/farmacologia , Di-Hidropiridinas/uso terapêutico , Herpes Simples/patologia , Herpes Simples/prevenção & controle , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Masculino , Meningoencefalite/patologia , Meningoencefalite/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
INTRODUCTION: The angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas axis could modulate the heart rate (HR) and blood pressure variabilities (BPV) which are important predictors of cardiovascular risk and provide information about the autonomic modulation of the cardiovascular system. Therefore we investigated the effect of Mas deficiency on autonomic modulation in wild type and Mas-knockout (KO) mice. METHODS: Blood pressure was recorded at high sample rate (4000 Hz). Stationary sequences of 200-250 beats were randomly chosen. Frequency domain analysis of HR and BPV was performed with an autoregressive algorithm on the pulse interval sequences and on respective systolic sequences. RESULTS: The KO group presented an increase of systolic arterial pressure (SAP; 127.26±11.20 vs 135.07±6.98 mmHg), BPV (3.54±1.54 vs 5.87±2.12 mmHg(2)), and low-frequency component of systolic BPV (0.12±0.11 vs 0.47±0.34 mmHg(2)). CONCLUSIONS: The deletion of Mas receptor is associated with an increase of SAP and with an increased BPV, indicating alterations in autonomic control. Increase of sympathetic vascular modulation in absence of Mas evidences the important role of Ang-(1-7)/Mas on cardiovascular regulation. Moreover, the absence of significant changes in HR and HRV can indicate an adaptation of autonomic cardiac balance. Our results suggest that the Ang-(1-7)/Mas axis seems more important in autonomic modulation of arterial pressure than HR.
Assuntos
Vasos Sanguíneos/metabolismo , Proteínas Proto-Oncogênicas/deficiência , Receptores Acoplados a Proteínas G/deficiência , Sistema Nervoso Simpático/metabolismo , Animais , Hemodinâmica , Masculino , Camundongos Knockout , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , SístoleRESUMO
Metabolic dysfunction is associated with adipose tissue inflammation and macrophage infiltration. PAFR (platelet-activating factor receptor) is expressed in several cell types and binds to PAF (platelet-activating factor) and oxidized phospholipids. Engagement of PAFR in macrophages drives them towards the anti-inflammatory phenotype. In the present study, we investigated whether genetic deficiency of PAFR affects the phenotype of ATMs (adipose tissue macrophages) and its effect on glucose and insulin metabolism. PARFKO (PAFR-knockout) and WT (wild-type) mice were fed on an SD (standard diet) or an HFD (high-fat diet). Glucose and insulin tolerance tests were performed by blood monitoring. ATMs were evaluated by FACS for phenotypic markers. Gene and protein expression was investigated by real-time reverse transcription-quantitative PCR and Western blotting respectively. Results showed that the epididymal adipose tissue of PAFRKO mice had increased gene expression of Ccr7, Nos2, Il6 and Il12, associated with pro-inflammatory mediators, and reduced expression of the anti-inflammatory Il10. Moreover, the adipose tissue of PAFRKO mice presented more pro-inflammatory macrophages, characterized by an increased frequency of F4/80(+)CD11c(+) cells. Blood monocytes of PAFRKO mice also exhibited a pro-inflammatory phenotype (increased frequency of Ly6C(+) cells) and PAFR ligands were detected in the serum of both PAFRKO and WT mice. Regarding metabolic parameters, compared with WT, PAFRKO mice had: (i) higher weight gain and serum glucose concentration levels; (ii) decreased insulin-stimulated glucose disappearance; (iii) insulin resistance in the liver; (iv) increased expression of Ldlr in the liver. In mice fed on an HFD, some of these changes were potentiated, particularly in the liver. Thus it seems that endogenous ligands of PAFR are responsible for maintaining the anti-inflammatory profile of blood monocytes and ATMs under physiological conditions. In the absence of PAFR signalling, monocytes and macrophages acquire a pro-inflammatory phenotype, resulting in adipose tissue inflammation and metabolic dysfunction.
Assuntos
Tecido Adiposo/metabolismo , Metabolismo Energético , Inflamação/prevenção & controle , Macrófagos/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Glicemia/metabolismo , Células Cultivadas , Dieta Hiperlipídica , Modelos Animais de Doenças , Regulação da Expressão Gênica , Genótipo , Homeostase , Inflamação/genética , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Insulina/sangue , Resistência à Insulina , Ligantes , Camundongos Endogâmicos BALB C , Camundongos Knockout , Fenótipo , Glicoproteínas da Membrana de Plaquetas/deficiência , Glicoproteínas da Membrana de Plaquetas/genética , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais , Fatores de Tempo , Aumento de PesoRESUMO
Beyond the classical actions of the renin-angiotensin system on the regulation of cardiovascular homeostasis, several studies have shown its involvement in acute and chronic inflammation. The G protein-coupled receptor Mas is a functional binding site for the angiotensin-(1-7); however, its role in the immune system has not been fully elucidated. In this study, we evaluated the effect of genetic deletion of Mas receptor in lipopolysaccharide (LPS)-induced systemic and cerebral inflammation in mice. Inflammatory response was triggered in Mas deficient (Mas(-/-)) and C57BL/6 wild-type (WT) mice (8-12 weeks-old) by intraperitoneal injection of LPS (5 mg/kg). Mas(-/-) mice presented more intense hypothermia compared to WT mice 24 h after LPS injection. Systemically, the bone marrow of Mas(-/-) mice contained a lower number of neutrophils and monocytes 3 h and 24 h after LPS injection, respectively. The plasma levels of inflammatory mediators KC, MCP-1 and IL-10 were higher in Mas(-/-) mice 24 h after LPS injection in comparison to WT. In the brain, Mas(-/-) animals had a significant increase in the number of adherent leukocytes to the brain microvasculature compared to WT mice, as well as, increased number of monocytes and neutrophils recruited to the pia-mater. The elevated number of adherent leukocytes on brain microvasculature in Mas(-/-) mice was associated with increased expression of CD11b - the alpha-subunit of the Mac-1 integrin - in bone marrow neutrophils 3h after LPS injection, and with increased brain levels of chemoattractants KC, MIP-2 and MCP-1, 24 h later. In conclusion, we demonstrated that Mas receptor deficiency results in exacerbated inflammation in LPS-challenged mice, which suggest a potential role for the Mas receptor as a regulator of systemic and brain inflammatory response induced by LPS.
Assuntos
Inflamação/genética , Inflamação/imunologia , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/genética , Animais , Biomarcadores , Temperatura Corporal , Peso Corporal , Medula Óssea/patologia , Encéfalo/irrigação sanguínea , Encéfalo/imunologia , Encéfalo/metabolismo , Encéfalo/patologia , Antígeno CD11b/genética , Antígeno CD11b/metabolismo , Circulação Cerebrovascular , Quimiocinas/sangue , Quimiocinas/metabolismo , Quimiotaxia de Leucócito , Citocinas/sangue , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Inflamação/sangue , Inflamação/patologia , Contagem de Leucócitos , Lipopolissacarídeos/efeitos adversos , Masculino , Camundongos , Camundongos Knockout , Microcirculação , Monócitos/imunologia , Monócitos/metabolismo , Monócitos/patologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/patologia , Proto-Oncogene MasRESUMO
BACKGROUND & AIMS: Bile acids (BAs) regulate energy expenditure by activating G-protein Coupled Bile Acid Receptor Gpbar1/TGR5 by cAMP-dependent mechanisms. Cholecystectomy (XGB) increases BAs recirculation rates resulting in increased tissue exposure to BAs during the light phase of the diurnal cycle in mice. We aimed to determine: 1) the effects of XGB on basal metabolic rate (BMR) and 2) the roles of TGR5 on XGB-dependent changes in BMR. METHODS: BMR was determined by indirect calorimetry in wild type and Tgr5 deficient (Tgr5-/-) male mice. Bile flow and BAs secretion rates were measured by surgical diversion of biliary duct. Biliary BAs and cholesterol were quantified by enzymatic methods. BAs serum concentration and specific composition was determined by liquid chromatography/tandem mass spectrometry. Gene expression was determined by qPCR analysis. RESULTS: XGB increased biliary BAs and cholesterol secretion rates, and elevated serum BAs concentration in wild type and Tgr5-/- mice during the light phase of the diurnal cycle. BMR was ~25% higher in cholecystectomized wild type mice (p <0.02), whereas no changes were detected in cholecystectomized Tgr5-/- mice compared to wild-type animals. CONCLUSION: XGB increases BMR by TGR5-dependent mechanisms in mice.
Assuntos
Técnicas de Ablação , Metabolismo Basal , Colecistectomia , Vesícula Biliar/cirurgia , Receptores Acoplados a Proteínas G/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Ácidos e Sais Biliares/sangue , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Ritmo Circadiano , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/metabolismo , Oxirredução , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Acoplados a Proteínas G/deficiênciaRESUMO
The renin-angiotensin (Ang) system is involved in maintaining cardiovascular function by regulating blood pressure and electrolyte homeostasis. More recently, alternative pathways within the renin-angiotensin system have been described, such as the ACE-2/Ang-(1-7)/Mas axis, with opposite effects to the ones of the ACE/Ang-II/AT1 axis. Correspondingly, our previous work reported that Ang-(1-7) via its receptor Mas inhibits the mRNA expression of the proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor-α increased by lipopolysaccharide (LPS) in mouse peritoneal macrophages. These data led us to investigate the functional role of the Ang-(1-7)/Mas axis in an in vivo LPS model. In this work, we present evidence that Ang-(1-7) via Mas significantly reduced the LPS-increased production of circulating cytokines, such as IL-6, IL-12, and CXCL-1. This inhibitory effect was mediated by Mas because it was not detectable in Mas-deficient (Mas) mice. Accordingly, IL-6, CXCL-1, and CXCL-2 levels were higher after LPS treatment in the absence of Mas. Mas mice were less resistant to LPS-induced endotoxemia, their survival rate being 50% compared with 95% in wild-type mice. Telemetric analyses showed that Mas mice presented more pronounced LPS-induced hypothermia with a 3°C lower body temperature compared with wild-type mice. Altogether, our findings suggest that Ang-(1-7) and Mas inhibit LPS-induced cytokine production and hypothermia and thereby protect mice from the fatal consequences of endotoxemia.
Assuntos
Endotoxemia/complicações , Hipotermia/prevenção & controle , Proteínas Proto-Oncogênicas/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Angiotensina I/fisiologia , Animais , Células Cultivadas , Citocinas/biossíntese , Endotoxemia/metabolismo , Hipotermia/etiologia , Hipotermia/metabolismo , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos , Macrófagos Peritoneais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fragmentos de Peptídeos/fisiologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/deficiência , Receptores Acoplados a Proteínas G/deficiênciaRESUMO
OBJECTIVE: The role of platelet-activating factor (PAF) on diet-induced inflammatory and metabolic dysfunction is unknown. The effects of diet-induced metabolic and inflammatory dysfunction in mice with deletion of the PAF receptor (PAFR(-/-) ) were evaluated in this study. METHODS: Wild-type and PAFR(-/-) mice were fed chow (WT-C and PAFR(-/-) -C) or high-refined carbohydrate-containing diet (WT-HC and PAFR(-/-) -HC). PAFR(-/-) - RESULTS: HC mice gained more weight and adiposity than PAFR(-/-) -C and WT-HC mice. Lipogenesis increased and hormone-sensitive lipase expression decreased in PAFR(-/-) -HC compared to WT-HC mice. WT-HC mice had impaired glucose tolerance and insulin sensitivity compared to WT-C mice. In contrast, glucose tolerance and insulin sensitivity in PAFR(-/-) -HC mice were similar to that of lean littermates. PAFR(-/-) -HC mice expressed significantly more peroxisome proliferator-activator receptor gamma (PPARγ) than PAFR(-/-) -C and WT-C mice. Resistin increased in WT-HC mice compared to WT-C mice. However, the levels of resistin were 35% lower in PAFR(-/-) -HC mice than WT-HC mice. PAFR(-/-) presented with less HC diet-induced adipose tissue inflammation than WT mice. Adipocytes isolated from PAFR(-/-) mice incubated in media containing normal or high levels of glucose secreted less interleukin-6 and tumor necrosis factor alpha and presented lower rate of lipolysis than WT mice. CONCLUSION: PAFR deficiency resulted in less inflammation in adipose tissue and improvement in glucose homeostasis when fed the HC diet. The higher adiposity observed in PAFR(-/-) mice fed HC diet could be owing to the maintenance of insulin sensitivity, decreased adipocyte lipolysis rate, high lipogenesis and PPARγ expression, and lower inflammatory milieu in adipose tissue.
Assuntos
Dieta , Carboidratos da Dieta/efeitos adversos , Inflamação/metabolismo , Glicoproteínas da Membrana de Plaquetas/deficiência , Glicoproteínas da Membrana de Plaquetas/metabolismo , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/metabolismo , Adipócitos/metabolismo , Tecido Adiposo , Adiposidade/fisiologia , Animais , Carboidratos da Dieta/administração & dosagem , Intolerância à Glucose , Resistência à Insulina , Interleucina-6/metabolismo , Lipogênese , Lipólise/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , PPAR gama/genética , PPAR gama/metabolismo , Glicoproteínas da Membrana de Plaquetas/genética , Receptores Acoplados a Proteínas G/genética , Resistina/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Aumento de PesoRESUMO
Periodontal disease (PD) is a chronic inflammatory and alveolar bone destructive disease triggered by oral biofilm-producing microorganisms, such as Aggregatibacter actinomycetemcomitans. The levels of the phospholipid platelet-activating factor (PAF) in the saliva, gingival crevicular fluid, and periodontal tissues are significantly increased during inflammatory conditions, such as PD, but the exact mechanism that links PAF to alveolar bone resorption is not well understood. In the current study, alveolar bone resorption was induced by experimental PD through the oral inoculation of A. actinomycetemcomitans in wild-type (WT) and PAF receptor knockout (Pafr(-/-)) mice. In vitro experiments using A. actinomycetemcomitans lipopolysaccharide (LPS)-stimulated RAW 264.7 cells treated with a PAF receptor antagonist (UK74505) were also performed. The expression of lyso-PAF acetyltransferase in periodontal tissues was significantly increased 3 h after A. actinomycetemcomitans LPS injection in mice. WT and Pafr(-/-) mice that were subjected to oral inoculation of A. actinomycetemcomitans presented neutrophil accumulation and increased levels of CXCL-1 and tumor necrosis factor alpha (TNF-α) in periodontal tissues. However, Pafr(-/-) mice presented less alveolar bone loss than WT mice. The in vitro blockade of the PAF receptor impaired the resorptive activity of A. actinomycetemcomitans LPS-activated osteoclasts. In conclusion, this study shows for the first time that the blockade of PAF receptor may contribute to the progression of PD triggered by A. actinomycetemcomitans by directly affecting the differentiation and activity of osteoclasts.