RESUMEN
Men with nonalcoholic fatty liver disease (NAFLD) are more exposed to nonalcoholic steatohepatitis (NASH) and liver fibrosis than women. However, the underlying molecular mechanisms of NALFD sex dimorphism are unclear. We combined gene expression, histological and lipidomic analyses to systematically compare male and female liver steatosis. We characterized hepatosteatosis in three independent mouse models of NAFLD, ob/ob and lipodystrophic fat-specific (PpargFΔ/Δ) and whole-body PPARγ-null (PpargΔ/Δ) mice. We identified a clear sex dimorphism occurring only in PpargΔ/Δ mice, with females showing macro- and microvesicular hepatosteatosis throughout their entire life, while males had fewer lipid droplets starting from 20 weeks. This sex dimorphism in hepatosteatosis was lost in gonadectomized PpargΔ/Δ mice. Lipidomics revealed hepatic accumulation of short and highly saturated TGs in females, while TGs were enriched in long and unsaturated hydrocarbon chains in males. Strikingly, sex-biased genes were particularly perturbed in both sexes, affecting lipid metabolism, drug metabolism, inflammatory and cellular stress response pathways. Most importantly, we found that the expression of key sex-biased genes was severely affected in all the NAFLD models we tested. Thus, hepatosteatosis strongly affects hepatic sex-biased gene expression. With NAFLD increasing in prevalence, this emphasizes the urgent need to specifically address the consequences of this deregulation in humans.
Asunto(s)
Enfermedad del Hígado Graso no Alcohólico/patología , PPAR gamma/deficiencia , Caracteres Sexuales , Animales , Modelos Animales de Enfermedad , Ácidos Grasos/metabolismo , Femenino , Regulación de la Expresión Génica , Hormonas Esteroides Gonadales/metabolismo , Inflamación/patología , Gotas Lipídicas/metabolismo , Hígado/metabolismo , Hígado/patología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/genética , PPAR gamma/metabolismo , Fenotipo , Transducción de Señal , Triglicéridos/metabolismoRESUMEN
Long-term neurological recovery after severe traumatic brain injury (TBI) is strongly linked to the repair and functional restoration of injured white matter. Emerging evidence suggests that the anti-inflammatory cytokine interleukin-4 (IL-4) plays an important role in promoting white matter integrity after cerebral ischemic injury. Here, we report that delayed intranasal delivery of nanoparticle-packed IL-4 boosted sensorimotor neurological recovery in a murine model of controlled cortical impact, as assessed by a battery of neurobehavioral tests for up to five weeks. Post-injury IL-4 treatment failed to reduce macroscopic brain lesions after TBI, but preserved the structural and functional integrity of white matter, at least in part through oligodendrogenesis. IL-4 directly facilitated the differentiation of oligodendrocyte progenitor cells (OPCs) into mature myelin-producing oligodendrocytes in primary cultures, an effect that was attenuated by selective PPARγ inhibition. IL-4 treatment after TBI in vivo also failed to stimulate oligodendrogenesis or improve white matter integrity in OPC-specific PPARγ conditional knockout (cKO) mice. Accordingly, IL-4-afforded improvements in sensorimotor neurological recovery after TBI were markedly impaired in the PPARγ cKO mice compared to wildtype controls. These results support IL-4 as a potential novel neurorestorative therapy to improve white matter functionality and mitigate the long-term neurological consequences of TBI.
Asunto(s)
Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Interleucina-4/uso terapéutico , Oligodendroglía/metabolismo , PPAR gamma/metabolismo , Sustancia Blanca/patología , Administración Intranasal , Animales , Conducta Animal/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Interleucina-4/química , Interleucina-4/farmacología , Liposomas/química , Masculino , Ratones , Ratones Transgénicos , Vaina de Mielina/metabolismo , Oligodendroglía/citología , PPAR gamma/deficiencia , PPAR gamma/genética , Recuperación de la FunciónRESUMEN
BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) agonists frequently induce cell death in human non-small-cell lung cancer (NSCLC) cells. However, majority of NSCLC patients acquire resistance after cancer therapy, and it is still unclear. METHODS: In this study we investigated the apoptotic mechanism and the anti-cancer effects of a novel purine-based PPARγ agonist, CB11 (8-(2-aminophenyl)-3-butyl-1,6,7-trimethyl-1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione), on human NSCLC cells. CB11 mediates PPARγ-dependent cell death, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) collapse, cell cycle arrest, lactate dehydrogenase (LDH) cytotoxicity, and caspase-3 activity in human NSCLC cells. RESULTS: CB11 causes cell death via ROS-mediated ATM-p53-GADD45α signalling in human NSCLC cells, and diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, decreases cell death by inhibiting CB11-mediated ATM signalling. In a xenograft experiment, CB11 dramatically reduced tumour volume when compared to a control group. Furthermore, CB11 induced cell death by inhibiting epithelial-to-mesenchymal transition (EMT) under radiation exposure in radiation-resistant human NSCLC cells. However, PPARγ deficiency inhibited cell death by blocking the ATM-p53 axis in radiation/CB11-induced radiation-resistant human NSCLC cells. CONCLUSIONS: Taken together, our results suggest that CB11, a novel PPARγ agonist, may be a novel anti-cancer agent, and it could be useful in a therapeutic strategy to overcome radio-resistance in radiation-exposed NSCLC.
Asunto(s)
Apoptosis/efectos de los fármacos , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Imidazoles/uso terapéutico , Neoplasias Pulmonares/radioterapia , PPAR gamma/agonistas , Purinas/uso terapéutico , Tolerancia a Radiación/efectos de los fármacos , Células 3T3 , Adipocitos/citología , Anilidas/farmacología , Animales , Proteínas de la Ataxia Telangiectasia Mutada/antagonistas & inhibidores , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Compuestos Azo , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Caspasa 3/metabolismo , Caspasa 9/metabolismo , Puntos de Control del Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Muerte Celular , Diferenciación Celular , Línea Celular Tumoral , Daño del ADN , Transición Epitelial-Mesenquimal/efectos de los fármacos , Transición Epitelial-Mesenquimal/efectos de la radiación , Femenino , Humanos , L-Lactato Deshidrogenasa , Ligandos , Luciferasas/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Potencial de la Membrana Mitocondrial , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Compuestos Onio/farmacología , PPAR gamma/deficiencia , PPAR gamma/metabolismo , ARN Interferente Pequeño , Tolerancia a Radiación/fisiología , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Tiazolidinedionas/farmacología , Carga Tumoral/efectos de los fármacos , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
RATIONALE: Peroxisome Proliferator Activator receptors (PPARs) are intracellular receptors that function as transcription factors, which regulate specific metabolic and inflammatory processes. PPARs are broadly distributed in the body and are also expressed in the central nervous system, especially in areas involved in addiction-related behavioral responses. Recent studies support a role of PPARs in alcoholism and pioglitazone: a PPARγ agonist used for treatment of type 2 diabetes showed efficacy in reducing alcohol drinking, stress-induced relapse, and alcohol withdrawal syndrome in rats. OBJECTIVES AND METHODS: In the current work, we tested the pharmacological effects of pioglitazone on binge-like alcohol consumption using an intermittent two-bottle choice paradigm in Wistar rats and on the "drinking in the dark" (DID) model in mice with selective deletion of PPARγ in neurons. RESULTS: Our data show that repeated administration of pioglitazone (10, 30 mg/kg) reduces high voluntary alcohol consumption in Wistar rats. Pre-treatment with the selective PPARγ antagonist GW9662 (5 mg/kg) completely prevented the effect of pioglitazone, demonstrating that its action is specifically mediated by activation of PPARγ. In line with this result, repeated administration of pioglitazone (30 mg/kg) attenuated binge alcohol consumption in PPARγ(+/+) mice. Whereas in PPARγ(-/-) mice, which exhibit reduced alcohol consumption, pioglitazone had no effect. Of note, PPARγ(-/-) mice exhibited lower patterns of alcohol drinking without showing difference in sucrose (control) intake. Interestingly, PPARγ(-/-) mice displayed a higher sensitivity to the sedative and ataxic effect of alcohol compared with their wild-type counterpart. CONCLUSIONS: Collectively, these data suggest that PPARγ agonists, and specifically pioglitazone, could be potential therapeutics for the treatment of binge alcohol drinking.
Asunto(s)
Consumo de Bebidas Alcohólicas/tratamiento farmacológico , Etanol/administración & dosificación , PPAR gamma/agonistas , PPAR gamma/antagonistas & inhibidores , Pioglitazona/uso terapéutico , Consumo de Bebidas Alcohólicas/metabolismo , Consumo de Bebidas Alcohólicas/psicología , Anilidas/farmacología , Animales , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , PPAR gamma/deficiencia , Pioglitazona/farmacología , Ratas , Ratas Wistar , Roedores/metabolismoRESUMEN
Mast cells (MCs) play a central role in IgE-dependent immune responses. PPARγ is a nuclear receptor that is essential for adipocyte differentiation and insulin sensitivity. Although PPARγ is expressed in activated MCs, the effect of PPARγ suppression in IgE-mediated activation of MCs is largely unknown. In the current study, we evaluated the effect of PPARγ knockdown on the function of IgE plus antigen (Ag)-stimulated MCs using siRNA-transfected bone marrow-derived MCs (BMMCs). We found that the mRNA expression level of cytokines in IgE/Ag-stimulated BMMCs was significantly increased in PPARγ knockdown BMMCs, and IgE/Ag-mediated degranulation and the protein production level of TNF-α was moderately increased by PPARγ knockdown, whereas the cell surface expression level of FcεRI was not affected by PPARγ knockdown. Oral administration of pioglitazone (PPARγ agonist) significantly suppressed body temperature change of mice in passive systemic anaphylaxis, supporting the inhibitory functions of PPARγ in IgE/Ag-dependent activation of MCs in vivo. IgE-mediated up-regulation of mRNA levels of Ptgs2 (encoding COX-2) was drastically enhanced in PPARγ knockdown BMMCs. Although several prostaglandin (PG) derivatives are known to be ligands for PPARγ, treatment with a COX inhibitor, acetyl salicylic acid, up-regulated the IgE-mediated increase of Il13, Tnf and Ptgs2 mRNA levels in a synergistic manner with PPARγ siRNA. Knockdown of COX-1 and/or COX-2 by siRNA showed that suppression of IgE/Ag-mediated activation was mainly dependent on COX-1. Taken together, these results indicate that PPARγ suppresses IgE/Ag-induced transactivation of cytokine genes and the Ptgs2 gene in MCs in a manner distinguishable from that of PGs.
Asunto(s)
Células de la Médula Ósea/inmunología , Inmunoglobulina E/inmunología , Mastocitos/inmunología , PPAR gamma/inmunología , Animales , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , PPAR gamma/agonistas , PPAR gamma/deficiencia , ARN Interferente Pequeño/farmacologíaRESUMEN
BACKGROUND: Despite its established significance in fibrotic cardiac remodeling, clinical benefits of global inhibition of TGF (transforming growth factor)-ß1 signaling remain controversial. LRG1 (leucine-rich-α2 glycoprotein 1) is known to regulate endothelial TGFß signaling. This study evaluated the role of LRG1 in cardiac fibrosis and its transcriptional regulatory network in cardiac fibroblasts. METHODS: Pressure overload-induced heart failure was established by transverse aortic constriction. Western blot, quantitative reverse transcription polymerase chain reaction, immunofluorescence, and immunohistochemistry were used to evaluate the expression level and pattern of interested targets or pathology during fibrotic cardiac remodeling. Cardiac function was assessed by pressure-volume loop analysis. RESULTS: LRG1 expression was significantly suppressed in left ventricle of mice with transverse aortic constriction-induced fibrotic cardiac remodeling (mean difference, -0.00085 [95% CI, -0.0013 to -0.00043]; P=0.005) and of patients with end-stage ischemic-dilated cardiomyopathy (mean difference, 0.13 [95% CI, 0.012-0.25]; P=0.032). More profound cardiac fibrosis (mean difference, -0.014% [95% CI, -0.029% to -0.00012%]; P=0.048 for interstitial fibrosis; mean difference, -1.3 [95% CI, -2.5 to -0.2]; P=0.016 for perivascular fibrosis), worse cardiac dysfunction (mean difference, -2.5 ms [95% CI, -4.5 to -0.4 ms]; P=0.016 for Tau-g; mean difference, 13% [95% CI, 2%-24%]; P=0.016 for ejection fraction), and hyperactive TGFß signaling in transverse aortic constriction-operated Lrg1-deficient mice (mean difference, -0.27 [95% CI, -0.47 to -0.07]; P<0.001), which could be reversed by cardiac-specific Lrg1 delivery mediated by adeno-associated virus 9. Mechanistically, LRG1 inhibits cardiac fibroblast activation by competing with TGFß1 for receptor binding, while PPAR (peroxisome proliferator-activated receptor)-ß/δ and TGFß1 collaboratively regulate LRG1 expression via SMRT (silencing mediator for retinoid and thyroid hormone receptor). We further demonstrated functional interactions between LRG1 and PPARß/δ in cardiac fibroblast activation. CONCLUSIONS: Our results established a highly complex molecular network involving LRG1, TGFß1, PPARß/δ, and SMRT in regulating cardiac fibroblast activation and cardiac fibrosis. Targeting LRG1 or PPARß/δ represents a promising strategy to control pathological cardiac remodeling in response to chronic pressure overload.
Asunto(s)
Fibroblastos/metabolismo , Glicoproteínas/metabolismo , Cardiopatías/metabolismo , Miocardio/metabolismo , PPAR gamma/metabolismo , PPAR-beta/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Función Ventricular Izquierda , Remodelación Ventricular , Adulto , Anciano , Animales , Células Cultivadas , Enfermedad Crónica , Modelos Animales de Enfermedad , Femenino , Fibroblastos/patología , Fibrosis , Glicoproteínas/deficiencia , Glicoproteínas/genética , Cardiopatías/patología , Cardiopatías/fisiopatología , Humanos , Masculino , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Miocardio/patología , Co-Represor 2 de Receptor Nuclear/metabolismo , PPAR gamma/deficiencia , PPAR gamma/genética , PPAR-beta/deficiencia , PPAR-beta/genética , Transducción de SeñalRESUMEN
Influenza virus causes a heterogeneous respiratory infectious disease ranging from self-limiting symptoms to non-resolving pathology in the lungs. Worldwide, seasonal influenza infections claim ~500,000 lives annually. Recent reports describe pathologic pulmonary sequelae that result in remodeling the architecture of lung parenchyma following respiratory infections. These dysfunctional recovery processes that disproportionately impact the elderly have been understudied. Macrophages are involved in tissue remodeling and are critical for survival of severe influenza infection. Here, we found intrinsic deficiency of the nuclear receptor PPAR-γ in myeloid cells delayed the resolution of pulmonary inflammation following influenza infection. Mice with myeloid cell-specific PPAR-γ deficiency subsequently presented with increased influenza-induced deposition of pulmonary collagen compared to control mice. This dysfunctional lung remodeling was progressive and sustained for at least 3 months following infection of mice with myeloid PPAR-γ deficiency. These progressive changes were accompanied by a pro-fibrotic gene signature from lung macrophages and preceded by deficiencies in activation of genes involved with damage repair. Importantly similar aberrant gene expression patterns were also found in a secondary analysis of a study where macrophages were isolated from patients with fibrotic interstitial lung disease. Quite unexpectedly, mice with PPAR-γ deficient macrophages were more resistant to bleomycin-induced weight loss whereas extracellular matrix deposition was unaffected compared to controls. Therefore PPAR-γ expression in macrophages may be a pathogen-specific limiter of organ recovery rather than a ubiquitous effector pathway in response to generic damage.
Asunto(s)
Virus de la Influenza A , Macrófagos Alveolares/metabolismo , Infecciones por Orthomyxoviridae/complicaciones , PPAR gamma/metabolismo , Fibrosis Pulmonar/etiología , Fibrosis Pulmonar/metabolismo , Animales , Biomarcadores , Bleomicina/efectos adversos , Colágeno/metabolismo , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Expresión Génica , Mediadores de Inflamación/metabolismo , Macrófagos Alveolares/inmunología , Ratones , Ratones Transgénicos , Células Mieloides/inmunología , Células Mieloides/metabolismo , Infecciones por Orthomyxoviridae/virología , PPAR gamma/deficiencia , PPAR gamma/genética , Neumonía/complicaciones , Neumonía/etiología , Neumonía/patología , Fibrosis Pulmonar/patologíaRESUMEN
BACKGROUND: Obesity is associated with cardiovascular complications, including pulmonary hypertension (PH). Reports suggest that peroxisome proliferator-activated receptor-γ (PPARγ) has direct action in preventing vascular remodelling in PH. Here we dissected the specific role of high-fat-diet (HFD)-induced obesity and vascular smooth muscle cell (VSMC)-PPARγ for remodelling of small pulmonary arteries. METHODS: Wild-type (WT) and VSMC-specific PPARγ-knockout (SmPparγ-/-) mice were fed a low-fat-diet (LFD, 10% kcal from fat) or HFD (60% kcal from fat) for 24 weeks. Mice were metabolically phenotyped (e.g. weight development, insulin/glucose tolerance) at the beginning, and after 12 and 24 weeks, respectively. At 24 weeks additionally pulmonary pressure, heart structure, pulmonary vascular muscularization together with gene and protein expression in heart and lung tissues were determined. RESULTS: HFD increased right ventricular systolic pressure (RVSP) to a similar extent in WT and SmPparγ-/- mice. HFD decreased glucose tolerance and insulin sensitivity in both WT and SmPparγ-/- mice. Importantly, the increase in RVSP correlated with the degree of insulin resistance. However, VSMC-PPARγ deficiency increased pulmonary vascular muscularization independently of the diet-induced rise in RVSP. This increase was associated with elevated expression of early growth response protein 1 in heart and osteopontin in lung tissue. CONCLUSIONS: Here we demonstrate a correlation of insulin resistance and pulmonary pressure. Further, deficiency of PPARγ in VSMCs diet-independently leads to increased pulmonary vascular muscularization.
Asunto(s)
Hipertensión Pulmonar/metabolismo , Músculo Liso Vascular/metabolismo , Obesidad/metabolismo , PPAR gamma/deficiencia , Arteria Pulmonar/metabolismo , Remodelación Vascular/fisiología , Animales , Células Cultivadas , Dieta Alta en Grasa/efectos adversos , Hipertensión Pulmonar/patología , Resistencia a la Insulina/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Liso Vascular/patología , Obesidad/patología , Arteria Pulmonar/patología , Distribución AleatoriaRESUMEN
We established a murine model of multiwall carbon nanotube (MWCNT)-elicited chronic granulomatous disease that bears similarities to human sarcoidosis pathology, including alveolar macrophage deficiency of peroxisome proliferator-activated receptor γ (PPARγ). Because lymphocyte reactivity to mycobacterial antigens has been reported in sarcoidosis, we hypothesized that addition of mycobacterial ESAT-6 (early secreted antigenic target protein 6) to MWCNT might exacerbate pulmonary granulomatous pathology. MWCNTs with or without ESAT-6 peptide 14 were instilled by the oropharyngeal route into macrophage-specific PPARγ-knockout (KO) or wild-type mice. Control animals received PBS or ESAT-6. Lung tissues, BAL cells, and BAL fluid were evaluated 60 days after instillation. PPARγ-KO mice receiving MWCNT + ESAT-6 had increased granulomas and significantly elevated fibrosis (trichrome staining) compared with wild-type mice or PPARγ-KO mice that received only MWCNT. Immunostaining of lung tissues revealed elevated fibronectin and Siglec F expression on CD11c+ infiltrating alveolar macrophages in the presence of MWCNT + ESAT-6 compared with MWCNT alone. Analyses of BAL fluid proteins indicated increased levels of transforming growth factor (TGF)-ß and the TGF-ß pathway mediator IL-13 in PPARγ-KO mice that received MWCNT + ESAT-6 compared with wild-type or PPARγ-KO mice that received MWCNT. Similarly, mRNA levels of matrix metalloproteinase 9, another requisite factor for TGF-ß production, was elevated in PPARγ-KO mice by MWCNT + ESAT-6. Analysis of ESAT-6 in lung tissues by mass spectrometry revealed ESAT-6 retention in lung tissues of PPARγ-KO but not wild-type mice. These data indicate that PPARγ deficiency promotes pulmonary ESAT-6 retention, exacerbates macrophage responses to MWCNT + ESAT-6, and intensifies pulmonary fibrosis. The present findings suggest that the model may facilitate understanding of the effects of environmental factors on sarcoidosis-associated pulmonary fibrosis.
Asunto(s)
Antígenos Bacterianos/farmacología , Proteínas Bacterianas/farmacología , Macrófagos Alveolares/metabolismo , PPAR gamma/deficiencia , Fibrosis Pulmonar/microbiología , Sarcoidosis Pulmonar/microbiología , Animales , Lavado Broncoalveolar , Líquido del Lavado Bronquioalveolar , Antígenos CD11/metabolismo , Modelos Animales de Enfermedad , Fibronectinas/metabolismo , Fibrosis/metabolismo , Inflamación , Pulmón/patología , Macrófagos/metabolismo , Espectrometría de Masas , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Nanotubos de Carbono/química , PPAR gamma/genética , Fibrosis Pulmonar/genética , Sarcoidosis Pulmonar/patologíaRESUMEN
Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor γ (PPARγ) agonists that represent an effective class of insulin-sensitizing agents; however, clinical use is associated with weight gain and peripheral edema. To elucidate the role of PPARγ expression in endothelial cells (ECs) in these side effects, EC-targeted PPARγ knockout (Pparg ΔEC) mice were placed on a high-fat diet to promote PPARγ agonist-induced plasma volume expansion, and then treated with the TZD rosiglitazone. Compared with Pparg-floxed wild-type control (Pparg f/f) mice, Pparg ΔEC treated with rosiglitazone are resistant to an increase in extracellular fluid, water content in epididymal and inguinal white adipose tissue, and plasma volume expansion. Interestingly, histologic assessment confirmed significant rosiglitazone-mediated capillary dilation within white adipose tissue of Pparg f/f mice, but not Pparg ΔEC mice. Analysis of ECs isolated from untreated mice in both strains suggested the involvement of changes in endothelial junction formation. Specifically, compared with cells from Pparg f/f mice, Pparg ΔEC cells had a 15-fold increase in focal adhesion kinase, critically important in EC focal adhesions, and >3-fold significant increase in vascular endothelial cadherin, the main component of focal adhesions. Together, these results indicate that rosiglitazone has direct effects on the endothelium via PPARγ activation and point toward a critical role for PPARγ in ECs during rosiglitazone-mediated plasma volume expansion.
Asunto(s)
Tejido Adiposo/metabolismo , Células Endoteliales/metabolismo , Hipoglucemiantes/farmacología , PPAR gamma/deficiencia , Rosiglitazona/farmacología , Remodelación Vascular/fisiología , Tejido Adiposo/irrigación sanguínea , Tejido Adiposo/efectos de los fármacos , Animales , Células Endoteliales/efectos de los fármacos , Eliminación de Gen , Masculino , Ratones , Ratones Transgénicos , PPAR gamma/genética , Volumen Plasmático/efectos de los fármacos , Volumen Plasmático/fisiología , Remodelación Vascular/efectos de los fármacosRESUMEN
BACKGROUND: Exercise is a powerful tool for prevention and treatment of many conditions related to the cardiovascular system and also chronic low-grade inflammation. Peroxisome proliferator-activated receptors γ (PPARγ) exerts an import role on the regulation of metabolic profile and subsequent inflammatory response, especially in macrophages. PURPOSE: To investigate the effects of 8-week moderate-exercise training on metabolic and inflammatory parameters in mice with PPARγ deficiency in myeloid cells. METHODS: Twelve-week old mice bearing PPARγ deletion exclusively in myeloid cells (PPARγlox/lox Lys Cre -/+ , knockout [KO]) and littermate controls (PPARγlox/lox Lys Cre -/- , wild type [WT]) were submitted to 8-week exercise training (treadmill running at moderate intensity, 5 days/week). Animals were evaluated for food intake, glucose homeostasis, serum metabolites, adipose tissue and peritoneal macrophage inflammation, and basal and stimulated cytokine secretion. RESULTS: Exercise protocol did not improve glucose metabolism or adiponectin concentrations in serum of KO mice. Moreover, the absence of PPARγ in macrophages exacerbated the proinflammatory profile in sedentary mice. Peritoneal cultured cells had higher tumor necrosis factor-α (TNF-α) secretion in nonstimulated and lipopolysaccharide (LPS)-stimulated conditions and higher Toll-4 receptor (TLR4) gene expression under LPS stimulus. Trained mice showed reduced TNF-α content in adipose tissue independently of the genotype. M2 polarization ability was impaired in KO peritoneal macrophages after exercise training, while adipose tissue-associated macrophages did not present any effect by PPARγ ablation. CONCLUSION: Overall, PPARγ seems necessary to maintain macrophages appropriate response to inflammatory stimulus and macrophage polarization, affecting also whole body lipid metabolism and adiponectin profile. Exercise training showed as an efficient mechanism to restore the immune response impaired by PPARγ deletion in macrophages.
Asunto(s)
Plasticidad de la Célula , Metabolismo Energético , Mediadores de Inflamación/metabolismo , Macrófagos Peritoneales/metabolismo , PPAR gamma/deficiencia , Condicionamiento Físico Animal/métodos , Adiponectina/sangre , Tejido Adiposo/metabolismo , Animales , Células Cultivadas , Eliminación de Gen , Lípidos/sangre , Macrófagos Peritoneales/inmunología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , PPAR gamma/genética , Fenotipo , Resistencia Física , Factores de TiempoRESUMEN
Pathogen immune responses are profoundly attenuated in fetuses and premature infants, yet the mechanisms underlying this developmental immaturity remain unclear. Here we show transcriptomic, metabolic and polysome profiling and find that monocytes isolated from infants born early in gestation display perturbations in PPAR-γ-regulated metabolic pathways, limited glycolytic capacity and reduced ribosomal activity. These metabolic changes are linked to a lack of translation of most cytokines and of MALT1 signalosome genes essential to respond to the neonatal pathogen Candida. In contrast, they have little impact on house-keeping phagocytosis functions. Transcriptome analyses further indicate a role for mTOR and its putative negative regulator DNA Damage Inducible Transcript 4-Like in regulating these metabolic constraints. Our results provide a molecular basis for the broad susceptibility to multiple pathogens in these infants, and suggest that the fetal immune system is metabolically programmed to avoid energetically costly, dispensable and potentially harmful immune responses during ontogeny.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Inmunidad Innata , Monocitos/inmunología , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/inmunología , PPAR gamma/inmunología , Factores de Transcripción/inmunología , Adulto , Proteína 10 de la LLC-Linfoma de Células B/deficiencia , Proteína 10 de la LLC-Linfoma de Células B/genética , Proteína 10 de la LLC-Linfoma de Células B/inmunología , Proteínas Adaptadoras de Señalización CARD/deficiencia , Proteínas Adaptadoras de Señalización CARD/genética , Proteínas Adaptadoras de Señalización CARD/inmunología , Candida albicans/inmunología , Candida parapsilosis/inmunología , Humanos , Recién Nacido , Recien Nacido Prematuro , Interleucinas/deficiencia , Interleucinas/genética , Interleucinas/inmunología , Lectinas Tipo C/deficiencia , Lectinas Tipo C/genética , Lectinas Tipo C/inmunología , Lipopolisacáridos/farmacología , Análisis por Micromatrices , Monocitos/citología , Monocitos/efectos de los fármacos , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/deficiencia , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , PPAR gamma/deficiencia , PPAR gamma/genética , Cultivo Primario de Células , Biosíntesis de Proteínas/inmunología , Serina-Treonina Quinasas TOR/deficiencia , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/inmunología , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Transcriptoma/inmunología , Factor de Necrosis Tumoral alfa/deficiencia , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
Despite the important functions of PPARγ in various cell types of the lung, PPARγ-deficiency in club cells induces only mild emphysema. Peroxisomes are distributed in a similar way as PPARγ in the lung and are mainly enriched in club and AECII cells. To date, the effects of PPARγ-deficiency on the overall peroxisomal compartment and its metabolic alterations in pulmonary club cells are unknown. Therefore, we characterized wild-type and club cell-specific PPARγ knockout-mice lungs and used C22 cells to investigate the peroxisomal compartment and its metabolic roles in the distal airway epithelium by means of 1) double-immunofluorescence labelling for peroxisomal proteins, 2) laser-assisted microdissection of the bronchiolar epithelium and subsequent qRT-PCR, 3) siRNA-transfection of PPARγand PPRE dual-luciferase reporter activity in C22 cells, 4) PPARg inhibition by GW9662, 5) GC-MS based lipid analysis. Our results reveal elevated levels of fatty acids, increased expression of PPARα and PPRE activity, a strong overall upregulation of the peroxisomal compartment and its associated gene expression (biogenesis, α-oxidation, ß-oxidation, and plasmalogens) in PPARγ-deficient club cells. Interestingly, catalase was significantly increased and mistargeted into the cytoplasm, suggestive for oxidative stress by the PPARγ-deficiency in club cells. Taken together, PPARα-mediated metabolic induction and proliferation of peroxisomes via a PPRE-dependent mechanism could compensate PPARγ-deficiency in club cells.
Asunto(s)
Bronquios/metabolismo , Regulación de la Expresión Génica , PPAR alfa/biosíntesis , PPAR gamma/deficiencia , Peroxisomas/metabolismo , Enfisema Pulmonar/metabolismo , Anilidas/farmacología , Animales , Bronquios/patología , Ratones , Ratones Noqueados , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/genética , PPAR alfa/antagonistas & inhibidores , PPAR alfa/genética , Peroxisomas/genética , Enfisema Pulmonar/genética , Enfisema Pulmonar/patologíaRESUMEN
Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear transcription factor belonging to the superfamily of ligand-activated nuclear receptors. It is activated by diverse endogenous lipid metabolites as well as by exogenous ligands such as the thiazolidinediones. It regulates cellular metabolism, proliferation, differentiation, and inflammation, the latter in part through trans-repression of pro-inflammatory cytokines. PPARγ is highly expressed in alternatively activated alveolar macrophages (AMs), a primary host cell for airborne Mycobacterium tuberculosis (M.tb). Our previous in vitro study identified the importance of PPARγ activation through the mannose receptor (CD206) on human macrophages in enabling M. tb growth. The aim of the current study was to investigate the role of PPARγ in vivo during M. tb infection using a macrophage-specific PPARγ knock out mouse model with special emphasis on the lung environment. Our data show that the absence of PPARγ in lung macrophages reduces the growth of virulent M. tb, enhances pro-inflammatory cytokines and reduces granulomatous infiltration. These findings demonstrate that PPARγ activation, which down-regulates macrophage pro-inflammatory responses, impacts the lung's response to M. tb infection, thereby supporting PPARγ's role in tuberculosis (TB) pathogenesis.
Asunto(s)
Eliminación de Gen , Pulmón/metabolismo , Macrófagos Alveolares/metabolismo , Mycobacterium tuberculosis/patogenicidad , PPAR gamma/genética , Tuberculosis Pulmonar/prevención & control , Animales , Carga Bacteriana , Células Cultivadas , Citocinas/inmunología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Interacciones Huésped-Patógeno , Mediadores de Inflamación/inmunología , Mediadores de Inflamación/metabolismo , Pulmón/inmunología , Pulmón/microbiología , Macrófagos Alveolares/inmunología , Macrófagos Alveolares/microbiología , Ratones Endogámicos BALB C , Ratones Noqueados , Mycobacterium tuberculosis/crecimiento & desarrollo , Mycobacterium tuberculosis/inmunología , Mycobacterium tuberculosis/metabolismo , PPAR gamma/deficiencia , PPAR gamma/inmunología , Transducción de Señal , Tuberculosis Pulmonar/genética , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/microbiología , VirulenciaRESUMEN
PURPOSE: Arterial stiffness is an inevitable consequence of the aging process and is considered an early stage in the development of cardiovascular diseases. The perivascular adipose tissue (PVAT) is a distinct functional integral layer of the vasculature actively involved in blood pressure regulation and atherosclerosis development via PVAT-derived paracrine/autocrine factors. However, there is little knowledge regarding the relationship between PVAT and arterial stiffness. METHODS: Using unique mice lacking PVAT, high-fat diet-induced obesity, and in mice overexpressing brown adipocyte selective mitoNEET, we investigated the relationship between PVAT and arterial stiffness in mice. RESULTS: We found that lack of PVAT enhanced arterial stiffness in aging mice. High-fat diet feeding of aging C57BL/6J wild-type mice significantly induced hypertrophic PVAT and enhanced arterial stiffness. Furthermore, the expression of mitoNEET, a mitochondrial membrane protein related to energy expenditure, was significantly increased by pioglitazone treatment, while reduced in the hypertrophic PVAT induced by high-fat diet. Overexpression of mitoNEET in PVAT reduced the expression of inflammatory genes and was associated with lower pulse wave velocity in aging mice. CONCLUSIONS: These data indicate that local PVAT homeostasis especially inflammation in PVAT is associated with arterial stiffness development. Pioglitazone-induced mitoNEET in PVAT prevents PVAT inflammation and is negatively associated with arterial stiffness. These findings provide new experimental insight into the roles of pioglitazone on PVAT in arterial stiffness and indicate that PVAT might be a target to treat or prevent cardiovascular disease.
Asunto(s)
Tejido Adiposo Pardo/metabolismo , Envejecimiento/metabolismo , Enfermedades Cardiovasculares/metabolismo , Proteínas de Unión a Hierro/metabolismo , Proteínas de la Membrana/metabolismo , Obesidad/metabolismo , Rigidez Vascular , Tejido Adiposo Pardo/efectos de los fármacos , Tejido Adiposo Pardo/fisiopatología , Adiposidad , Factores de Edad , Envejecimiento/genética , Animales , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/fisiopatología , Enfermedades Cardiovasculares/prevención & control , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados para ApoE , Obesidad/genética , Obesidad/fisiopatología , PPAR gamma/deficiencia , PPAR gamma/genética , Pioglitazona/farmacología , Transducción de Señal , Rigidez Vascular/efectos de los fármacosRESUMEN
Objective- Perivascular adipose tissue (PVAT) contributes to vascular homeostasis by producing paracrine factors. Previously, we reported that selective deletion of PPARγ (peroxisome proliferator-activated receptor γ) in vascular smooth muscle cells resulted in concurrent loss of PVAT and enhanced atherosclerosis in mice. To address the causal relationship between loss of PVAT and atherosclerosis, we used BA-PPARγ-KO (brown adipocyte-specific PPARγ knockout) mice. Approach and Results- Deletion of PPARγ in brown adipocytes did not affect PPARγ in white adipocytes or vascular smooth muscle cells or PPARα and PPARδ expression in brown adipocytes. However, development of PVAT and interscapular brown adipose tissue was remarkably impaired, associated with reduced expression of genes encoding lipogenic enzymes in the BA-PPARγ-KO mice. Thermogenesis in brown adipose tissue was significantly impaired with reduced expression of thermogenesis genes in brown adipose tissue and compensatory increase in subcutaneous and gonadal white adipose tissues. Remarkably, basal expression of inflammatory genes and macrophage infiltration in PVAT and brown adipose tissue were significantly increased in the BA-PPARγ-KO mice. BA-PPARγ-KO mice were crossbred with ApoE KO (apolipoprotein E knockout) mice to investigate the development of atherosclerosis. Flow cytometry analysis confirmed increased systemic and PVAT inflammation. Consequently, atherosclerotic lesions were significantly increased in mice with impaired PVAT development, thus indicating that the lack of normal PVAT is sufficient to drive increased atherosclerosis. Conclusions- PPARγ is required for functional PVAT development. PPARγ deficiency in PVAT, while still expressed in vascular smooth muscle cell, enhances atherosclerosis and results in vascular and systemic inflammation, providing new insights on the specific roles of PVAT in atherosclerosis and cardiovascular disease at large.
Asunto(s)
Adipocitos Marrones/metabolismo , Adipogénesis , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Enfermedades de la Aorta/metabolismo , Aterosclerosis/metabolismo , PPAR gamma/deficiencia , Adipocitos Marrones/patología , Tejido Adiposo Pardo/patología , Tejido Adiposo Pardo/fisiopatología , Tejido Adiposo Blanco/patología , Tejido Adiposo Blanco/fisiopatología , Adiposidad , Animales , Enfermedades de la Aorta/genética , Enfermedades de la Aorta/patología , Enfermedades de la Aorta/fisiopatología , Aterosclerosis/genética , Aterosclerosis/patología , Aterosclerosis/fisiopatología , Modelos Animales de Enfermedad , Femenino , Regulación de la Expresión Génica , Mediadores de Inflamación/metabolismo , Lipogénesis/genética , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados para ApoE , PPAR gamma/genética , Placa Aterosclerótica , Transducción de Señal , TermogénesisRESUMEN
Peroxisome proliferator-activated receptor-γ (PPARγ), is a transcription factor that governs pathways, such as lipid metabolism and immune response, that have been implicated in the etiology of LOAD. Previously, we established HepG2-derived cell-lines with stable knockdown of PPARγ gene, and showed an increase in mRNA levels of genes mapped in the APOE linkage disequilibrium (LD) region on chromosome 19q13.32, with the greatest effect observed for APOE-mRNA. Here, we extended the analysis using our PPARγ knockdown model system and investigated the broader effect on expression changes of genes implicated in LOAD via genome wide association studies (GWAS). We applied the nCounter gene expression assay (NanoString) using a panel of twenty-four LOAD-associated genes inferred by proximity to the top significantly associated SNPs. Two independent PPARγ knockdown cell-lines showed changes in mRNA levels of a total of seven genes compared to a control HepG2 cell-line; six of which, ABCA7, APOE, CASS4, CELF1, PTK2B, and ZCWPW1, were upregulated and one, DSG2, was downregulated upon PPARγ knockdown. Our results propose that PPARγ may act as a master regulator of the transcription of several genes involved in LOAD pathogenesis. Our study provided the premise for further analyses including a larger set of genes positioned within a wider range of linkage disequilibrium (LD) regions tagged by all LOAD significantly associated SNPs.
Asunto(s)
Enfermedad de Alzheimer/genética , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , PPAR gamma/genética , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Edad de Inicio , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/fisiopatología , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Proteínas CELF1/genética , Proteínas CELF1/metabolismo , Desmogleína 2/genética , Desmogleína 2/metabolismo , Quinasa 2 de Adhesión Focal/genética , Quinasa 2 de Adhesión Focal/metabolismo , Perfilación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Estudio de Asociación del Genoma Completo , Células Hep G2 , Humanos , Desequilibrio de Ligamiento , Modelos Biológicos , PPAR gamma/antagonistas & inhibidores , PPAR gamma/deficiencia , Polimorfismo de Nucleótido Simple , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND AND AIMS: Agonists of peroxisome proliferator-activated receptor gamma (Pparγ) have been demonstrated to reduce the risk of myocardial infarction (MI) in clinical trials and animal experiments. However, the cellular and molecular mechanisms are not completely understood. We aimed to reveal the functions of myeloid Pparγ in MI and explore the potential mechanisms in this study. METHODS: Myeloid Pparγ knockout (MPGKO) mice (nâ¯=â¯12) and control mice (nâ¯=â¯8) underwent coronary artery ligation to induce MI. Another cohort of MPGKO mice and control mice underwent coronary artery ligation and were then treated with IgG or neutralizing antibodies against interleukin (IL)-1ß. Infarct size was determined by TTC staining and cardiac function was measured using echocardiography. Conditioned media from GW9662- or vehicle-treated macrophages were used to treat H9C2 cardiomyocyte cell line. Gene expression was analyzed using quantitative PCR. Reactive oxygen species were measured using flow cytometry. RESULTS: Myeloid Pparγ deficiency significantly increased myocardial infarct size. Cardiac hypertrophy was also exacerbated in MPGKO mice, with upregulation of ß-myosin heavy chain (Mhc) and brain natriuretic peptide (Bnp) and downregulation of α-Mhc in the non-infarcted zone. Conditioned media from GW9662-treated macrophages increased expression of ß-Mhc and Bnp in H9C2 cells. Echocardiographic measurements showed that MPGKO mice had worsen cardiac dysfunction after MI. Myeloid Pparγ deficiency increased gene expression of NADPH oxidase subunits (Nox2 and Nox4) in the non-infarcted zone after MI. Conditioned media from GW9662-treated macrophages increased reactive oxygen species in H9C2 cells. Expression of inflammatory genes such as IL-1ß and IL-6 was upregulated in the non-infarcted zone of MPGKO mice after MI. With the injection of neutralizing antibodies against IL-1ß, control mice and MPGKO mice had comparable cardiac function and expression of inflammatory genes after MI. CONCLUSIONS: Myeloid Pparγ deficiency exacerbates MI, likely through increased oxidative stress and cardiac inflammation.
Asunto(s)
Macrófagos Peritoneales/metabolismo , Infarto del Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , PPAR gamma/deficiencia , Animales , Línea Celular , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Predisposición Genética a la Enfermedad , Hipertrofia Ventricular Izquierda/genética , Hipertrofia Ventricular Izquierda/metabolismo , Hipertrofia Ventricular Izquierda/patología , Hipertrofia Ventricular Izquierda/fisiopatología , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Ratones Noqueados , Infarto del Miocardio/genética , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/patología , Cadenas Pesadas de Miosina/genética , Cadenas Pesadas de Miosina/metabolismo , NADPH Oxidasa 2/genética , NADPH Oxidasa 2/metabolismo , NADPH Oxidasa 4/genética , NADPH Oxidasa 4/metabolismo , Péptido Natriurético Encefálico/genética , Péptido Natriurético Encefálico/metabolismo , Estrés Oxidativo , PPAR gamma/genética , Fenotipo , Transducción de Señal , Factores de Tiempo , Función Ventricular Izquierda , Remodelación VentricularRESUMEN
It is well established that aging is associated with metabolic dysfunction such as increased adiposity and impaired energy dissipation; however, the transcriptional mechanisms regulating energy balance during late life stages have not yet been fully elucidated. Here, we show that ablation of the nuclear receptor PPARγ specifically in inguinal fat tissue in aging mice is associated with increased fat tissue expansion and insulin resistance. These metabolic effects are accompanied by decreased thermogenesis, reduced levels of brown fat genes, and browning of subcutaneous adipose tissue. Comparative studies of the effects of PPARγ downregulation in young and mid-aged mice demonstrate a preferential regulation of brown fat gene programs in inguinal fat in an age-dependent manner. In conclusion, our study uncovers an essential role for PPARγ in maintaining energy expenditure during the aging process and suggests the possibility of targeting PPARγ to counteract age-associated metabolic dysfunction.
Asunto(s)
Obesidad/metabolismo , PPAR gamma/metabolismo , Grasa Subcutánea/metabolismo , Adiposidad , Animales , Ratones , PPAR gamma/deficiencia , TermogénesisRESUMEN
Peroxisome proliferator-activated receptor-γ (PPARγ) plays an important role in lipid and glucose metabolism. In this study, the function of PPARγ on lung development was investigated. Lung-specific Pparg conditional knockout mice (PpargΔLuEpC) were developed using Cre-Lox system. PpargΔLuEpC mice showed abnormal lung development with enlarged airspaces and followed by increase of apoptotic cells at E14.5 to E18.5. Gene analysis revealed that expression of Pmaip1, a gene related to apoptosis, was significantly increased while expression of Retnla, a gene related to anti-apoptosis, was dramatically decreased in the fetal lung (E14.5) of PpargΔLuEpC mice. In addition, expression of Pthlh, a gene phenotypically expressed in the congenital cystic adenomatoid malformation (CCAM), was increased at E14.5 to E18.5 in the lung of PpargΔLuEpC mice. Cell culture studies revealed that PPARγ could bind to promoter region of Pthlh gene as a repressor in the immortalized mouse lung epithelial cell line MLE-15. Surprisingly, phenotypic changes in MLE-15-shPparg cells, stably transfected with shPparg plasmid, were similar to the PpargΔLuEpC mice model. In addition, MLE-15-shPparg cells were easily detached from the cultured plate when cold phosphate buffered saline was applied. Furthermore, expression of Cdh1, a gene related to cell adhesion, was significantly reduced in the MLE-15-shPparg cells. Taken together, PPARγ may play an important role in fetal lung development via alveolar cell-to-cell adhesion system.