RESUMO
Birth presents a metabolic challenge to cardiomyocytes as they reshape fuel preference from glucose to fatty acids for postnatal energy production1,2. This adaptation is triggered in part by post-partum environmental changes3, but the molecules orchestrating cardiomyocyte maturation remain unknown. Here we show that this transition is coordinated by maternally supplied γ-linolenic acid (GLA), an 18:3 omega-6 fatty acid enriched in the maternal milk. GLA binds and activates retinoid X receptors4 (RXRs), ligand-regulated transcription factors that are expressed in cardiomyocytes from embryonic stages. Multifaceted genome-wide analysis revealed that the lack of RXR in embryonic cardiomyocytes caused an aberrant chromatin landscape that prevented the induction of an RXR-dependent gene expression signature controlling mitochondrial fatty acid homeostasis. The ensuing defective metabolic transition featured blunted mitochondrial lipid-derived energy production and enhanced glucose consumption, leading to perinatal cardiac dysfunction and death. Finally, GLA supplementation induced RXR-dependent expression of the mitochondrial fatty acid homeostasis signature in cardiomyocytes, both in vitro and in vivo. Thus, our study identifies the GLA-RXR axis as a key transcriptional regulatory mechanism underlying the maternal control of perinatal cardiac metabolism.
Assuntos
Ácidos Graxos , Glucose , Coração , Leite Humano , Ácido gama-Linolênico , Feminino , Humanos , Recém-Nascido , Gravidez , Cromatina/genética , Ácidos Graxos/metabolismo , Ácido gama-Linolênico/metabolismo , Ácido gama-Linolênico/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Coração/efeitos dos fármacos , Coração/embriologia , Coração/crescimento & desenvolvimento , Homeostase , Técnicas In Vitro , Leite Humano/química , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Receptores X de Retinoides/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Hematopoietic stem cells (HSCs) balance self-renewal and differentiation to maintain hematopoietic fitness throughout life. In steady-state conditions, HSC exhaustion is prevented by the maintenance of most HSCs in a quiescent state, with cells entering the cell cycle only occasionally. HSC quiescence is regulated by retinoid and fatty-acid ligands of transcriptional factors of the nuclear retinoid X receptor (RXR) family. Herein, we show that dual deficiency for hematopoietic RXRα and RXRß induces HSC exhaustion, myeloid cell/megakaryocyte differentiation, and myeloproliferative-like disease. RXRα and RXRß maintain HSC quiescence, survival, and chromatin compaction; moreover, transcriptome changes in RXRα;RXRß-deficient HSCs include premature acquisition of an aging-like HSC signature, MYC pathway upregulation, and RNA intron retention. Fitness loss and associated RNA transcriptome and splicing alterations in RXRα;RXRß-deficient HSCs are prevented by Myc haploinsufficiency. Our study reveals the critical importance of RXRs for the maintenance of HSC fitness and their protection from premature aging.
Assuntos
Células-Tronco Hematopoéticas , Transdução de Sinais , Receptores X de Retinoides , Células-Tronco Hematopoéticas/metabolismo , Diferenciação Celular/genética , HomeostaseRESUMO
BACKGROUND: The diagnosis of acute myocarditis typically requires either endomyocardial biopsy (which is invasive) or cardiovascular magnetic resonance imaging (which is not universally available). Additional approaches to diagnosis are desirable. We sought to identify a novel microRNA for the diagnosis of acute myocarditis. METHODS: To identify a microRNA specific for myocarditis, we performed microRNA microarray analyses and quantitative polymerase-chain-reaction (qPCR) assays in sorted CD4+ T cells and type 17 helper T (Th17) cells after inducing experimental autoimmune myocarditis or myocardial infarction in mice. We also performed qPCR in samples from coxsackievirus-induced myocarditis in mice. We then identified the human homologue for this microRNA and compared its expression in plasma obtained from patients with acute myocarditis with the expression in various controls. RESULTS: We confirmed that Th17 cells, which are characterized by the production of interleukin-17, are a characteristic feature of myocardial injury in the acute phase of myocarditis. The microRNA mmu-miR-721 was synthesized by Th17 cells and was present in the plasma of mice with acute autoimmune or viral myocarditis but not in those with acute myocardial infarction. The human homologue, designated hsa-miR-Chr8:96, was identified in four independent cohorts of patients with myocarditis. The area under the receiver-operating-characteristic curve for this novel microRNA for distinguishing patients with acute myocarditis from those with myocardial infarction was 0.927 (95% confidence interval, 0.879 to 0.975). The microRNA retained its diagnostic value in models after adjustment for age, sex, ejection fraction, and serum troponin level. CONCLUSIONS: After identifying a novel microRNA in mice and humans with myocarditis, we found that the human homologue (hsa-miR-Chr8:96) could be used to distinguish patients with myocarditis from those with myocardial infarction. (Funded by the Spanish Ministry of Science and Innovation and others.).
Assuntos
MicroRNA Circulante/sangue , MicroRNAs/sangue , Infarto do Miocárdio/diagnóstico , Miocardite/diagnóstico , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/metabolismo , Biomarcadores/sangue , Antígenos CD4 , Diagnóstico Diferencial , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Miocardite/genética , Reação em Cadeia da Polimerase , Curva ROC , Linfócitos T/imunologia , Linfócitos T/metabolismo , Células Th17/metabolismoRESUMO
INTRODUCTION: Collaboration between Primary Care (PC) and Gastroenterology in inflammatory bowel disease (IBD) is crucial to provide high-quality healthcare. The aim of this study is to analyse the relationship between PC and gastroenterologists at a national level in order to identify areas for improvement in the management of patients with inflammatory bowel disease (IBD) and how to address them, with the aim of subsequently developing concrete proposals and projects between SEMERGEN and GETECCU. METHODS: Descriptive, observational, cross-sectional study, was carried out using an anonymous online questionnaire between October 2021 and March 2022. RESULTS: A total of 157 surveys from Gastroenterology and 222 from PC were collected. 43.8% and 34.3% of gastroenterologists and family practitioners, respectively, considered that there was a good relationship between the units. The level of knowledge from family practitioners regarding different aspects of IBD out of 10 was: clinical 6.67±1.48, diagnosis 6.47±1.46, treatment 5.63±1.51, follow-up 5.53±1.68 and complications 6.05±1.54. The perception of support between both units did not exceed 4.5 on a scale from 0 to 10 in either of the surveys. The most highly voted improvement proposals were better coordination between the units, implementation of IBD units, and nursing collaboration. CONCLUSION: There are deficiencies in the relationship between PC and Gastroenterology with special dedication to IBD that require the efforts of the scientific societies that represent them for greater coordination with the development of joint protocols and agile, fast, and effective communication channels.
Assuntos
Colite Ulcerativa , Doença de Crohn , Doenças Inflamatórias Intestinais , Médicos de Atenção Primária , Humanos , Colite Ulcerativa/terapia , Doença de Crohn/terapia , Estudos Transversais , Doenças Inflamatórias Intestinais/terapia , Inquéritos e QuestionáriosRESUMO
Nuclear receptors (NRs) are a superfamily of ligand-activated transcription factors that act as biological sensors and use a combination of mechanisms to modulate positively and negatively gene expression in a spatial and temporal manner. The highly orchestrated biological actions of several NRs influence the proliferation, differentiation, and apoptosis of many different cell types. Synthetic ligands for several NRs have been the focus of extensive drug discovery efforts for cancer intervention. This review summarizes the roles in tumour growth and metastasis of several relevant NR family members, namely androgen receptor (AR), estrogen receptor (ER), glucocorticoid receptor (GR), thyroid hormone receptor (TR), retinoic acid receptors (RARs), retinoid X receptors (RXRs), peroxisome proliferator-activated receptors (PPARs), and liver X receptors (LXRs). These studies are key to develop improved therapeutic agents based on novel modes of action with reduced side effects and overcoming resistance.
Assuntos
Hormônios , Lipídeos , Neoplasias , Receptores Citoplasmáticos e Nucleares , Animais , HumanosRESUMO
RARA and RXRA contribute to myeloid maturation in both mice and humans, and deletion of Rxra and Rxrb augments leukemic growth in mice. While defining the domains of RXRA that are required for anti-leukemic effects in murine KMT2A-MLLT3 leukemia cells, we unexpectedly identified RXRA DT448/9PP as a constitutively active variant capable of inducing maturation and loss of their proliferative phenotype. RXRA DT448/9PP was associated with ligand-independent activity in reporter assays, with enhanced co-activator interactions, reduced engraftment in vivo, and activation of myeloid maturation transcriptional signatures that overlapped with those of cells treated with the potent RXRA agonist bexarotene, suggestive of constitutive activity that leads to leukemic maturation. Phenotypes of RXRA DT448/9PP appear to differ from those of two other RXRA mutations with forms of constitutive activity (F318A and S427F), in that DT448/9PP activity was resistant to mutations at critical ligand-interacting amino acids (R316A/L326A) and was resistant to pharmacological antagonists, suggesting it may be ligand-independent. These data provide further evidence that activated retinoid X receptors can regulate myeloid maturation and provide a novel constitutively active variant that may be germane for broader studies of retinoid X receptors in other settings.
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Leucemia Mieloide Aguda , Leucemia Promielocítica Aguda , Receptor X Retinoide alfa , Animais , Proteínas de Ligação a DNA , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Promielocítica Aguda/tratamento farmacológico , Camundongos , Receptor X Retinoide alfa/genética , Receptor X Retinoide alfa/metabolismoRESUMO
Microelimination strategies for the hepatitis C virus (HCV) in vulnerable populations, such as users of Addiction Centres (AC), are key for the elimination of hepatitis C. The aim of the HepCelentes project was to design a certification program for AC from the generation of a guide with the criteria to favour the prevention, diagnosis, control, and treatment of HCV in Spain. The project was structured in 4 phases: normalisation, implementation, certification, and communication. In the first phase, developed between July and December 2020, a Steering Committee was created (formed by representatives of scientific societies, healthcare professionals from AC, primary care centres and hospital units, and patient associations) that, from of an exhaustive bibliographic review, generated by consensus an accreditation guide for AC. The guide consists of 22 criteria (15 mandatory and 7 recommended) structured based on the requirements to be met by AC, justification for the selection, level of action (management, prevention, diagnosis and treatment/follow-up), measurement of the indicator, objective level to be achieved, evidence of compliance, clarifications to improve understanding, and mandatory / recommendation (depending on their relevance to achieve HCV elimination and its feasibility for implementation in real practice). The development of a certification system for the AC, based on consensus and coordination of multidisciplinary teams, is intended to favour the management of hepatitis C and its elimination in AC users, supporting the international, national, and regional elimination strategies.
Las estrategias de microeliminación del virus de la hepatitis C (VHC) en poblaciones vulnerables, como los usuarios de los centros de adicciones (CA), son fundamentales para lograr la eliminación de la hepatitis C. El objetivo del proyecto HepCelentes fue diseñar un programa de certificación para los CA, a partir de la generación de una guía con los criterios para favorecer la prevención, diagnóstico, control y tratamiento del VHC en España. El proyecto se estructuró en 4 fases: normalización, implementación, certificación y comunicación. En la primera fase, desarrollada entre julio y diciembre de 2020, se creó un Comité de Normalización (formado por representantes de sociedades científicas, profesionales sanitarios de CA, centros de atención primaria, unidades hospitalarias, y asociaciones de pacientes) que, a partir de una revisión bibliográfica exhaustiva, generó por consenso una guía de certificación de los CA. La guía consta de 22 criterios (15 obligatorios y 7 recomendados) estructurados en base a la definición del criterio, justificación de su selección, nivel de actuación (gestión, prevención, diagnóstico y tratamiento/seguimiento), fórmula de medición, nivel objetivo a alcanzar, evidencias de su cumplimiento, aclaraciones para mejorar su comprensión y obligatoriedad/recomendación (en función de la relevancia en la eliminación y capacidad de implementación). El desarrollo de un sistema de certificación para los CA, a partir del consenso y la coordinación de equipos multidisciplinares, pretende favorecer el manejo de la hepatitis C y su eliminación en los usuarios de los CA, apoyando las estrategias de eliminación internacionales, nacionales y autonómicas.
RESUMO
Retinoid therapy transformed response and survival outcomes in acute promyelocytic leukemia (APL), but has demonstrated only modest activity in non-APL forms of acute myeloid leukemia (AML). The presence of natural retinoids in vivo could influence the efficacy of pharmacologic agonists and antagonists. We found that natural RXRA ligands, but not RARA ligands, were present in murine MLL-AF9-derived myelomonocytic leukemias in vivo and that the concurrent presence of receptors and ligands acted as tumor suppressors. Pharmacologic retinoid responses could be optimized by concurrent targeting RXR ligands (e.g. bexarotene) and RARA ligands (e.g. all-trans retinoic acid, ATRA), which induced either leukemic maturation or apoptosis depending on cell culture conditions. Co-repressor release from the RARA:RXRA heterodimer occurred with RARA activation, but not RXRA activation, providing an explanation for the combination synergy. Combination synergy could be replicated in additional, but not all, AML cell lines and primary samples, and was associated with improved survival in vivo, although tolerability of bexarotene administration in mice remained an issue. These data provide insight into the basal presence of natural retinoids in leukemias in vivo and a potential strategy for clinical retinoid combination regimens in leukemias beyond acute promyelocytic leukemia.
Assuntos
Leucemia Promielocítica Aguda , Retinoides , Animais , Diferenciação Celular , Camundongos , Receptores do Ácido Retinoico/genética , Tretinoína/farmacologiaRESUMO
The heart is the first organ to acquire its physiological function during development, enabling it to supply the organism with oxygen and nutrients. Given this early commitment, cardiomyocytes were traditionally considered transcriptionally stable cells fully committed to contractile function. However, growing evidence suggests that the maintenance of cardiac function in health and disease depends on transcriptional and epigenetic regulation. Several studies have revealed that the complex transcriptional alterations underlying cardiovascular disease (CVD) manifestations such as myocardial infarction and hypertrophy is mediated by cardiac retinoid X receptors (RXR) and their partners. RXRs are members of the nuclear receptor (NR) superfamily of ligand-activated transcription factors and drive essential biological processes such as ion handling, mitochondrial biogenesis, and glucose and lipid metabolism. RXRs are thus attractive molecular targets for the development of effective pharmacological strategies for CVD treatment and prevention. In this review, we summarize current knowledge of RXR partnership biology in cardiac homeostasis and disease, providing an up-to-date view of the molecular mechanisms and cellular pathways that sustain cardiomyocyte physiology.
Assuntos
Doenças Cardiovasculares/patologia , Fenômenos Fisiológicos Cardiovasculares , Regulação da Expressão Gênica , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/metabolismo , Humanos , Receptores Citoplasmáticos e Nucleares/genéticaRESUMO
Peroxisome proliferator-activated receptors (PPARs) are ligand-modulated nuclear receptors that play pivotal roles in nutrient sensing, metabolism, and lipid-related processes. Correct control of their target genes requires tight regulation of the expression of different PPAR isoforms in each tissue, and the dysregulation of PPAR-dependent transcriptional programs is linked to disorders, such as metabolic and immune diseases or cancer. Several PPAR regulators and PPAR-regulated factors are epigenetic effectors, including non-coding RNAs, epigenetic enzymes, histone modifiers, and DNA methyltransferases. In this review, we examine advances in PPARα and PPARγ-related epigenetic regulation in metabolic disorders, including obesity and diabetes, immune disorders, such as sclerosis and lupus, and a variety of cancers, providing new insights into the possible therapeutic exploitation of PPAR epigenetic modulation.
Assuntos
Epigênese Genética , Doenças do Sistema Imunitário/genética , Doenças Metabólicas/genética , Neoplasias/genética , PPAR alfa/genética , PPAR gama/genética , Animais , Metilação de DNA , Regulação da Expressão Gênica , Humanos , Doenças do Sistema Imunitário/metabolismo , Doenças do Sistema Imunitário/terapia , Doenças Metabólicas/metabolismo , Doenças Metabólicas/terapia , Neoplasias/metabolismo , Neoplasias/terapia , PPAR alfa/metabolismo , PPAR gama/metabolismoRESUMO
Background and Purpose- Phagocytic cells, such as microglia and blood-derived macrophages, are a key biological modality responsible for phagocytosis-mediated clearance of damaged, dead, or displaced cells that are compromised during senescence or pathological processes, including after stroke. This process of clearance is essential to eliminate the source of inflammation and to allow for optimal brain repair and functional recovery. Transcription factor, RXR (retinoic-X-receptor) is strongly implicated in phagocytic functions regulation, and as such could represent a novel target for brain recovery after stroke. Methods- Primary cultured microglia and bone marrow macrophages were used for phagocytic study. Mice with deleted RXR-α in myeloid phagocytes (Mac-RXR-α-/-) were subjected to transient middle cerebral artery occlusion to mimic ischemic stroke and then treated with RXR agonist bexarotene. RNA-sequencing and long-term recovery were evaluated. Results- Using cultured microglia, we demonstrated that the RXR-α promotes the phagocytic functions of microglia toward apoptotic neurons. Using mice with deleted RXR-α in myeloid phagocytes (Mac-RXR-α-/-), we have shown that despite behaving similarly to the control at early time points (up to 3 days, damage established histologically and behaviorally), these Mac-RXR-α-/- mice demonstrated worsened late functional recovery and developed brain atrophy that was larger in size than that seen in control mice. The RXR-α deficiency was associated with reduced expression of genes known to be under control of the prominent transcriptional RXR partner, PPAR (peroxisome proliferator-activated receptor)-γ, as well as genes encoding for scavenger receptors and genes that signify microglia/macrophages polarization to a reparative phenotype. Finally, we demonstrated that the RXR agonist, bexarotene, administered as late as 1 day after middle cerebral artery occlusion, improved neurological recovery, and reduced the atrophy volume as assessed 28 days after stroke. Bexarotene did not improve outcome in Mac-RXR-α-/- mice. Conclusions- Altogether, these data suggest that phagocytic cells control poststroke recovery and that RXR in these cells represents an attractive target with exceptionally long therapeutic window.
Assuntos
Isquemia Encefálica/imunologia , Encéfalo/imunologia , Regulação da Expressão Gênica/imunologia , Fagócitos/imunologia , Fagocitose , Receptor X Retinoide alfa/imunologia , Acidente Vascular Cerebral/imunologia , Animais , Bexaroteno/farmacologia , Encéfalo/patologia , Isquemia Encefálica/genética , Isquemia Encefálica/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Camundongos Knockout , Fagócitos/patologia , Receptor X Retinoide alfa/genética , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/patologiaRESUMO
RATIONALE: Myocardial infarction is a major cause of adult mortality worldwide. The origin(s) of cardiac fibroblasts that constitute the postinfarct scar remain controversial, in particular the potential contribution of bone marrow lineages to activated fibroblasts within the scar. OBJECTIVE: The aim of this study was to establish the origin(s) of infarct fibroblasts using lineage tracing and bone marrow transplants and a robust marker for cardiac fibroblasts, the Collagen1a1-green fluorescent protein reporter. METHODS AND RESULTS: Using genetic lineage tracing or bone marrow transplant, we found no evidence for collagen-producing fibroblasts derived from hematopoietic or bone marrow lineages in hearts subjected to permanent left anterior descending coronary artery ligation. In fact, fibroblasts within the infarcted area were largely of epicardial origin. Intriguingly, collagen-producing fibrocytes from hematopoietic lineages were observed attached to the epicardial surface of infarcted and sham-operated hearts in which a suture was placed around the left anterior descending coronary artery. CONCLUSIONS: In this controversial field, our study demonstrated that the vast majority of infarct fibroblasts were of epicardial origin and not derived from bone marrow lineages, endothelial-to-mesenchymal transition, or blood. We also noted the presence of collagen-producing fibrocytes on the epicardial surface that resulted at least in part from the surgical procedure.
Assuntos
Células da Medula Óssea/citologia , Linhagem da Célula , Infarto do Miocárdio/terapia , Miofibroblastos/citologia , Animais , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea/efeitos adversos , Células Cultivadas , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/patologia , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Pericárdio/citologiaRESUMO
The characterization of specialized cell subpopulations in a heterogeneous tissue is essential for understanding organ function in health and disease. A popular method of cell isolation is fluorescence-activated cell sorting (FACS) based on probes that bind surface or intracellular markers. In this study, we analyze the impact of FACS on the cell metabolome of mouse peritoneal macrophages. Compared with directly pelleted macrophages, FACS-treated cells had an altered content of metabolites related to the plasma membrane, activating a mechanosensory signaling cascade causing inflammation-like stress. The procedure also triggered alterations related to energy consumption and cell damage. The observed changes mostly derive from the physical impact on cells during their passage through the instrument. These findings provide evidence of FACS-induced biochemical changes, which should be taken into account in the design of robust metabolic assays of cells separated by flow cytometry.
Assuntos
Separação Celular , Citometria de Fluxo/normas , Metaboloma , Animais , Células Cultivadas , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/metabolismo , Camundongos , Projetos de PesquisaRESUMO
INTRODUCTION: Dyspepsia and Helicobacter pylori are two of the most relevant digestive conditions in primary care. Several consensuses on the subject have been published, but the assimilation/implementation of these guidelines is uncertain. AIMS AND METHODS: To evaluate the attitudes, perceptions, limitations, and adherence to recommendations of Spanish primary care physicians using an open online survey. Responses were anonymously codified. Estimated margin of error was 3.4%. Responses were weighted by province, gender, age, and type of practice. Survey was performed using the AEG-REDCap platform. RESULTS: A total of 1445 responses, received between December 2017 and April 2018, were analyzed. Women represented 54%, and the average age was 48 years; 59% were from urban context, 20% from semi-urban, and 21% from rural; 93% provided public practice. Over 40% had read at least one Maastricht consensus (24% Maastricht V), and 34% had attended a course related to H. pylori. 16% reported no direct access to any validated diagnostic method, only 44% to urea breath test, and 33% did not systematically refer to eradication confirmation test. The first-line treatment of choice was standard triple therapy in 56%, followed by concomitant therapy (28%). Only 20% of physicians had optimal adherence to recommendations. CONCLUSION: Even though some improvements from guidelines have been partially incorporated, the level of penetration of recommendations is still poor and delayed. To provide optimal primary care, the barriers for implementation, access to diagnostic tests and to continuous medical education, should be removed. Rigorous dissemination, implementation, and evaluation programs are desired in future consensuses.
Assuntos
Atitude Frente a Saúde , Dispepsia/psicologia , Infecções por Helicobacter/psicologia , Médicos de Atenção Primária/psicologia , Adulto , Idoso , Tomada de Decisões , Dispepsia/etnologia , Dispepsia/terapia , Feminino , Infecções por Helicobacter/etnologia , Infecções por Helicobacter/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Percepção , Atenção Primária à Saúde/estatística & dados numéricos , Espanha , Inquéritos e QuestionáriosRESUMO
Retinoid X receptors (RXRs) form a unique subclass within the nuclear receptor (NR) superfamily of ligand-dependent transcription factors. RXRs are obligatory partners for a number of other NRs, placing RXRs in a coordinating role at the crossroads of multiple signaling pathways. In addition, RXRs can function as self-sufficient homodimers. Recent advances have revealed RXRs as novel regulators of osteoclastogenesis and bone remodeling. This review outlines the versatility of RXR action in the control of transcription of bone-forming osteoblasts and bone-resorbing osteoclasts, both through heterodimerization with other NRs and through RXR homodimerization. RXR signaling is currently a major therapeutic target and, therefore, knowledge of how RXR signaling affects bone remodeling creates enormous potential for the translation of basic research findings into successful clinical therapies to increase bone mass and improve bone quality.
Assuntos
Remodelação Óssea , Receptores X de Retinoides/metabolismo , Animais , Reabsorção Óssea/patologia , Humanos , Modelos Biológicos , Multimerização ProteicaRESUMO
Pregnancy requires the adaptation of maternal energy metabolism including expansion and functional modifications of adipose tissue. Insulin resistance (IR), predominantly during late gestation, is a physiological metabolic adaptation that serves to support the metabolic demands of fetal growth. The molecular mechanisms underlying these adaptations are not fully understood and may contribute to gestational diabetes mellitus. Peroxisome proliferator-activated receptor gamma (PPARγ) controls adipogenesis, glucose and lipid metabolism and insulin sensitivity. The PPARγ2 isoform is mainly expressed in adipocytes and is thus likely to contribute to adipose tissue adaptation during late pregnancy. In the present study, we investigated the contribution of PPARγ2 to the metabolic adaptations occurring during the late phase of pregnancy in the context of IR. Using a model of late pregnancy in PPARγ2 knockout (KO) mice, we found that deletion of PPARγ2 exacerbated IR in association with lower serum adiponectin levels, increased body weight and enhanced lipid accumulation in liver. Lack of PPARγ2 provoked changes in the distribution of fat mass and preferentially prevented the expansion of the perigonadal depot while at the same time exacerbating inflammation. PPARγ2KO pregnant mice presented adipose tissue depot-dependent decreased expression of genes involved in lipid metabolism. Collectively, these data indicate that PPARγ2 is essential to promote healthy adipose tissue expansion and immune and metabolic functionality during pregnancy, contributing to the physiological adaptations that lead gestation to term.
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UNLABELLED: Despite the plethora of methods available for the functional analysis of omics data, obtaining comprehensive-yet detailed understanding of the results remains challenging. This is mainly due to the lack of publicly available tools for the visualization of this type of information. Here we present an R package called GOplot, based on ggplot2, for enhanced graphical representation. Our package takes the output of any general enrichment analysis and generates plots at different levels of detail: from a general overview to identify the most enriched categories (bar plot, bubble plot) to a more detailed view displaying different types of information for molecules in a given set of categories (circle plot, chord plot, cluster plot). The package provides a deeper insight into omics data and allows scientists to generate insightful plots with only a few lines of code to easily communicate the findings. AVAILABILITY AND IMPLEMENTATION: The R package GOplot is available via CRAN-The Comprehensive R Archive Network: http://cran.r-project.org/web/packages/GOplot. The shiny web application of the Venn diagram can be found at: https://wwalter.shinyapps.io/Venn/. A detailed manual of the package with sample figures can be found at https://wencke.github.io/ CONTACT: fscabo@cnic.es or mricote@cnic.es.
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Biologia Computacional/métodos , Gráficos por Computador , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Linguagens de Programação , Análise de Sequência de DNA/métodos , Software , Interpretação Estatística de Dados , Humanos , NavegadorRESUMO
The efficiency of central nervous system remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study, we show that expression of genes involved in the retinoid X receptor pathway are decreased with ageing in both myelin-phagocytosing human monocytes and mouse macrophages using a combination of in vivo and in vitro approaches. Disruption of retinoid X receptor function in young macrophages, using the antagonist HX531, mimics ageing by reducing myelin debris uptake. Macrophage-specific RXRα (Rxra) knockout mice revealed that loss of function in young mice caused delayed myelin debris uptake and slowed remyelination after experimentally-induced demyelination. Alternatively, retinoid X receptor agonists partially restored myelin debris phagocytosis in aged macrophages. The agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in multiple sclerosis patient monocytes to a more youthful profile and enhanced myelin debris phagocytosis by patient cells. These results reveal the retinoid X receptor pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics.
Assuntos
Envelhecimento/metabolismo , Envelhecimento/patologia , Bainha de Mielina/metabolismo , Fagocitose , Receptor X Retinoide alfa/metabolismo , Adulto , Animais , Benzoatos/farmacologia , Bexaroteno , Compostos de Bifenilo/farmacologia , Feminino , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Monócitos/citologia , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Esclerose Múltipla/metabolismo , Fagocitose/efeitos dos fármacos , Receptor X Retinoide alfa/agonistas , Receptor X Retinoide alfa/antagonistas & inibidores , Receptor X Retinoide alfa/genética , Transdução de Sinais/fisiologia , Tetra-Hidronaftalenos/farmacologia , Transcriptoma/efeitos dos fármacos , Adulto JovemRESUMO
Autoimmune glomerulonephritis is a common manifestation of systemic lupus erythematosus (SLE). In this study, we show that mice lacking macrophage expression of the heterodimeric nuclear receptors PPARγ or RXRα develop glomerulonephritis and autoantibodies to nuclear Ags, resembling the nephritis seen in SLE. These mice show deficiencies in phagocytosis and clearance of apoptotic cells, and they are unable to acquire an anti-inflammatory phenotype upon feeding of apoptotic cells, which is critical for the maintenance of self-tolerance. These results demonstrate that stimulation of PPARγ and RXRα in macrophages facilitates apoptotic cell engulfment, and they provide a potential strategy to avoid autoimmunity against dying cells and to attenuate SLE.