RESUMEN
In obesity, inflammation of white adipose tissue (AT) is associated with diminished generation of beige adipocytes ('beige adipogenesis'), a thermogenic and energy-dissipating function mediated by beige adipocytes that express the uncoupling protein UCP1. Here we delineated an inflammation-driven inhibitory mechanism of beige adipogenesis in obesity that required direct adhesive interactions between macrophages and adipocytes mediated by the integrin α4 and its counter-receptor VCAM-1, respectively; expression of the latter was upregulated in obesity. This adhesive interaction reciprocally and concomitantly modulated inflammatory activation of macrophages and downregulation of UCP1 expression dependent on the kinase Erk in adipocytes. Genetic or pharmacological inactivation of the integrin α4 in mice resulted in elevated expression of UCP1 and beige adipogenesis of subcutaneous AT in obesity. Our findings, established in both mouse systems and human systems, reveal a self-sustained cycle of inflammation-driven impairment of beige adipogenesis in obesity.
Asunto(s)
Adipocitos Beige , Adipogénesis/inmunología , Tejido Adiposo Blanco/inmunología , Diferenciación Celular/inmunología , Inflamación/inmunología , Macrófagos/inmunología , Obesidad/inmunología , Células 3T3-L1 , Adipocitos/inmunología , Adipocitos/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Animales , Adhesión Celular/inmunología , Dieta Alta en Grasa , Regulación hacia Abajo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Retroalimentación , Femenino , Técnicas de Silenciamiento del Gen , Humanos , Immunoblotting , Integrina alfa4/genética , Macrófagos/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Monocitos/inmunología , Obesidad/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Grasa Subcutánea , Linfocitos T/inmunología , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Molécula 1 de Adhesión Celular Vascular/genética , Molécula 1 de Adhesión Celular Vascular/metabolismo , Adulto JovenRESUMEN
Exosomes and other small extracellular vesicles (sEVs) provide a unique mode of cell-to-cell communication in which microRNAs (miRNAs) produced and released from one cell are taken up by cells at a distance where they can enact changes in gene expression1-3. However, the mechanism by which miRNAs are sorted into exosomes/sEVs or retained in cells remains largely unknown. Here we demonstrate that miRNAs possess sorting sequences that determine their secretion in sEVs (EXOmotifs) or cellular retention (CELLmotifs) and that different cell types, including white and brown adipocytes, endothelium, liver and muscle, make preferential use of specific sorting sequences, thus defining the sEV miRNA profile of that cell type. Insertion or deletion of these CELLmotifs or EXOmotifs in a miRNA increases or decreases retention in the cell of production or secretion into exosomes/sEVs. Two RNA-binding proteins, Alyref and Fus, are involved in the export of miRNAs carrying one of the strongest EXOmotifs, CGGGAG. Increased miRNA delivery mediated by EXOmotifs leads to enhanced inhibition of target genes in distant cells. Thus, this miRNA code not only provides important insights that link circulating exosomal miRNAs to tissues of origin, but also provides an approach for improved targeting in RNA-mediated therapies.
Asunto(s)
Vesículas Extracelulares , MicroARNs , Adipocitos/citología , Comunicación Celular , Endotelio/citología , Exosomas/genética , Exosomas/metabolismo , Vesículas Extracelulares/genética , Vesículas Extracelulares/metabolismo , Hígado/citología , MicroARNs/genética , MicroARNs/metabolismo , Músculos/citologíaRESUMEN
Muscle regeneration is a complex process relying on precise teamwork between multiple cell types, including muscle stem cells (MuSCs) and fibroadipogenic progenitors (FAPs). FAPs are also the main source of intramuscular adipose tissue (IMAT). Muscles without FAPs exhibit decreased IMAT infiltration but also deficient muscle regeneration, indicating the importance of FAPs in the repair process. Here, we demonstrate the presence of bidirectional crosstalk between FAPs and MuSCs via their secretion of extracellular vesicles (EVs) containing distinct clusters of miRNAs that is crucial for normal muscle regeneration. Thus, after acute muscle injury, there is activation of FAPs leading to a transient rise in IMAT. These FAPs also release EVs enriched with a selected group of miRNAs, a number of which come from an imprinted region on chromosome 12. The most abundant of these is miR-127-3p, which targets the sphingosine-1-phosphate receptor S1pr3 and activates myogenesis. Indeed, intramuscular injection of EVs from immortalized FAPs speeds regeneration of injured muscle. In late stages of muscle repair, in a feedback loop, MuSCs and their derived myoblasts/myotubes secrete EVs enriched in miR-206-3p and miR-27a/b-3p. The miRNAs repress FAP adipogenesis, allowing full muscle regeneration. Together, the reciprocal communication between FAPs and muscle cells via miRNAs in their secreted EVs plays a critical role in limiting IMAT infiltration while stimulating muscle regeneration, hence providing an important mechanism for skeletal muscle repair and homeostasis.
Asunto(s)
Vesículas Extracelulares , MicroARNs , Células Satélite del Músculo Esquelético , Fibras Musculares Esqueléticas , Comunicación , MicroARNs/genética , Regeneración/genéticaRESUMEN
Senescence in pancreatic beta cells plays a major role in beta cell dysfunction, which leads to impaired glucose homeostasis and diabetes. Therefore, prevention of beta cell senescence could reduce the risk of diabetes. Treatment of nonobese diabetic (NOD) mice, a model of type 1 autoimmune diabetes (T1D), with palmitic acid hydroxy stearic acids (PAHSAs), a novel class of endogenous lipids with antidiabetic and antiinflammatory effects, delays the onset and reduces the incidence of T1D from 82% with vehicle treatment to 35% with PAHSAs. Here, we show that a major mechanism by which PAHSAs protect islets of the NOD mice is by directly preventing and reversing the initial steps of metabolic stress-induced senescence. In vitro PAHSAs increased Mdm2 expression, which decreases the stability of p53, a key inducer of senescence-related genes. In addition, PAHSAs enhanced expression of protective genes, such as those regulating DNA repair and glutathione metabolism and promoting autophagy. We demonstrate the translational relevance by showing that PAHSAs prevent and reverse early stages of senescence in metabolically stressed human islets by the same Mdm2 mechanism. Thus, a major mechanism for the dramatic effect of PAHSAs in reducing the incidence of type 1 diabetes in NOD mice is decreasing cellular senescence; PAHSAs may have a similar benefit in humans.
Asunto(s)
Diabetes Mellitus Tipo 1 , Células Secretoras de Insulina , Humanos , Ratones , Animales , Ácido Palmítico/farmacología , Ácidos Esteáricos , Ratones Endogámicos NOD , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/prevención & control , Proteína p53 Supresora de Tumor/genética , Senescencia Celular/genética , Estrés Fisiológico , Proteínas Proto-Oncogénicas c-mdm2/genéticaRESUMEN
Adipose tissue is a major site of energy storage and has a role in the regulation of metabolism through the release of adipokines. Here we show that mice with an adipose-tissue-specific knockout of the microRNA (miRNA)-processing enzyme Dicer (ADicerKO), as well as humans with lipodystrophy, exhibit a substantial decrease in levels of circulating exosomal miRNAs. Transplantation of both white and brown adipose tissue-brown especially-into ADicerKO mice restores the level of numerous circulating miRNAs that are associated with an improvement in glucose tolerance and a reduction in hepatic Fgf21 mRNA and circulating FGF21. This gene regulation can be mimicked by the administration of normal, but not ADicerKO, serum exosomes. Expression of a human-specific miRNA in the brown adipose tissue of one mouse in vivo can also regulate its 3' UTR reporter in the liver of another mouse through serum exosomal transfer. Thus, adipose tissue constitutes an important source of circulating exosomal miRNAs, which can regulate gene expression in distant tissues and thereby serve as a previously undescribed form of adipokine.
Asunto(s)
Tejido Adiposo/metabolismo , Regulación de la Expresión Génica , MicroARNs/sangre , MicroARNs/metabolismo , Comunicación Paracrina , Regiones no Traducidas 3'/genética , Adipoquinas/metabolismo , Tejido Adiposo/trasplante , Tejido Adiposo Pardo/citología , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Pardo/trasplante , Tejido Adiposo Blanco/metabolismo , Tejido Adiposo Blanco/trasplante , Animales , Exosomas/genética , Factores de Crecimiento de Fibroblastos/sangre , Factores de Crecimiento de Fibroblastos/genética , Genes Reporteros/genética , Prueba de Tolerancia a la Glucosa , Hígado/metabolismo , Masculino , Ratones , MicroARNs/genética , Modelos Biológicos , Especificidad de Órganos/genética , ARN Mensajero/genética , Ribonucleasa III/deficiencia , Ribonucleasa III/genética , Transcripción GenéticaRESUMEN
BACKGROUND: Local relapse and peritoneal carcinomatosis (PC) for pT4 colon cancer is estimated in 15,6% and 36,7% for 12 months and 36 months from surgical resection respectively, achieving a 5 years overall survival of 6%. There are promising results using prophylactic HIPEC in this group of patients, and it is estimated that up to 26% of all T4 colon cancer could benefit from this treatment with a minimal morbidity. Adjuvant HIPEC is effective to avoid the possibility of peritoneal seeding after surgical resection. Taking into account these results and the cumulative experience in HIPEC use, we will lead a randomized controlled trial to determine the effectiveness and safety of adjuvant treatment with HIPEC vs. standard treatment in patients with colon cancer at high risk of peritoneal recurrence (pT4). METHODS/DESIGN: The aim of this study is to determine the effectiveness and safety of adjuvant HIPEC in preventing the development of PC in patients with colon cancer with a high risk of peritoneal recurrence (cT4). This study will be carried out in 15 Spanish HIPEC centres. Eligible for inclusion are patients who underwent curative resection for cT4NxM0 stage colon cancer. After resection of the primary tumour, 200 patients will be randomized to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy in the experimental arm, or to systemic chemotherapy only in the control arm. Adjuvant HIPEC will be performed simultaneously after the primary resection. Mitomycin C will be used as chemotherapeutic agent, for 60 min at 42-43 °C. Primary endpoint is loco-regional control (LC) in months and the rate of loco-regional control (%LC) at 12 months and 36 months after resection. DISCUSSION: We assumed that adjuvant HIPEC will reduce the expected absolute risk of peritoneal recurrence from 36% to 18% at 36 months for T4 colon-rectal carcinoma. TRIAL REGISTRATION: NCT02614534 ( clinicaltrial.gov ) Nov-2015.
Asunto(s)
Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/terapia , Hipertermia Inducida/métodos , Mitomicina/uso terapéutico , Adulto , Anciano , Antibióticos Antineoplásicos/uso terapéutico , Terapia Combinada , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Resultado del Tratamiento , Adulto JovenRESUMEN
Emerging evidence points to a close crosstalk between metabolic organs and innate immunity in the course of metabolic disorders. In particular, cellular and humoral factors of innate immunity are thought to contribute to metabolic dysregulation of the adipose tissue or the liver, as well as to dysfunction of the pancreas; all these conditions are linked to the development of insulin resistance and diabetes mellitus. A central component of innate immunity is the complement system. Interestingly, the classical view of complement as a major system of host defense that copes with infections is changing to that of a multi-functional player in tissue homeostasis, degeneration, and regeneration. In the present review, we will discuss the link between complement and metabolic organs, focusing on the pancreas, adipose tissue, and liver and the diverse effects of complement system on metabolic disorders.
Asunto(s)
Proteínas del Sistema Complemento/fisiología , Diabetes Mellitus/inmunología , Enfermedades Metabólicas/inmunología , Pancreatitis/inmunología , Tejido Adiposo/inmunología , Animales , Homeostasis , Humanos , Inmunidad Innata , Resistencia a la Insulina , Hígado/inmunología , Hígado/metabolismo , Regeneración HepáticaRESUMEN
The immune system plays an instrumental role in obesity and insulin resistance. Here, we unravel the role of the costimulatory molecule CD40 and its signaling intermediates, TNF receptor-associated factors (TRAFs), in diet-induced obesity (DIO). Although not exhibiting increased weight gain, male CD40(-/-) mice in DIO displayed worsened insulin resistance, compared with wild-type mice. This worsening was associated with excessive inflammation of adipose tissue (AT), characterized by increased accumulation of CD8(+) T cells and M1 macrophages, and enhanced hepatosteatosis. Mice with deficient CD40-TRAF2/3/5 signaling in MHCII(+) cells exhibited a similar phenotype in DIO as CD40(-/-) mice. In contrast, mice with deficient CD40-TRAF6 signaling in MHCII(+) cells displayed no insulin resistance and showed a reduction in both AT inflammation and hepatosteatosis in DIO. To prove the therapeutic potential of inhibition of CD40-TRAF6 in obesity, DIO mice were treated with a small-molecule inhibitor that we designed to specifically block CD40-TRAF6 interactions; this compound improved insulin sensitivity, reduced AT inflammation, and decreased hepatosteatosis. Our study reveals that the CD40-TRAF2/3/5 signaling pathway in MHCII(+) cells protects against AT inflammation and metabolic complications associated with obesity whereas CD40-TRAF6 interactions in MHCII(+) cells aggravate these complications. Inhibition of CD40-TRAF6 signaling by our compound may provide a therapeutic option in obesity-associated insulin resistance.
Asunto(s)
Antígenos CD40/metabolismo , Resistencia a la Insulina/inmunología , Obesidad/inmunología , Transducción de Señal/inmunología , Factor 6 Asociado a Receptor de TNF/metabolismo , Tejido Adiposo/citología , Tejido Adiposo/inmunología , Tejido Adiposo/patología , Análisis de Varianza , Animales , Compuestos Azo , Antígenos CD40/antagonistas & inhibidores , Antígenos CD40/genética , Linfocitos T CD8-positivos/inmunología , Calorimetría , Hígado Graso/etiología , Hígado Graso/patología , Citometría de Flujo , Ligandos , Espectroscopía de Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/complicaciones , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal/efectos de los fármacos , Resonancia por Plasmón de Superficie , Factor 6 Asociado a Receptor de TNF/antagonistas & inhibidoresRESUMEN
The neural crest-derived adrenal medulla is closely related to the sympathetic nervous system; however, unlike neural tissue, it is characterized by high plasticity which suggests the involvement of stem cells. Here, we show that a defined pool of glia-like nestin-expressing progenitor cells in the adult adrenal medulla contributes to this plasticity. These glia-like cells have features of adrenomedullary sustentacular cells, are multipotent, and are able to differentiate into chromaffin cells and neurons. The adrenal is central to the body's response to stress making its proper adaptation critical to maintaining homeostasis. Our results from stress experiments in vivo show the activation and differentiation of these progenitors into new chromaffin cells. In summary, we demonstrate the involvement of a new glia-like multipotent stem cell population in adrenal tissue adaptation. Our data also suggest the contribution of stem and progenitor cells in the adaptation of neuroendocrine tissue function in general.
Asunto(s)
Adaptación Fisiológica , Médula Suprarrenal/citología , Diferenciación Celular/fisiología , Células Cromafines/citología , Células Madre Multipotentes/citología , Neuronas/citología , Estrés Fisiológico , Animales , Ratones Endogámicos C57BL , Ratones Transgénicos , Neuroglía/citologíaAsunto(s)
Taponamiento Cardíaco/etiología , Quistes/complicaciones , Hepatopatías/complicaciones , Anciano , Taponamiento Cardíaco/diagnóstico por imagen , Quistes/diagnóstico por imagen , Ecocardiografía , Femenino , Humanos , Hepatopatías/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
UNLABELLED: The low-grade inflammatory state present in obesity contributes to obesity-related metabolic dysregulation, including nonalcoholic steatohepatitis (NASH) and insulin resistance. Intercellular interactions between immune cells or between immune cells and hepatic parenchymal cells contribute to the exacerbation of liver inflammation and steatosis in obesity. The costimulatory molecules, B7.1 and B7.2, are important regulators of cell-cell interactions in several immune processes; however, the role of B7 costimulation in obesity-related liver inflammation is unknown. Here, diet-induced obesity (DIO) studies in mice with genetic inactivation of both B7.1 and B7.2 (double knockout; DKO) revealed aggravated obesity-related metabolic dysregulation, reduced insulin signalling in the liver and adipose tissue (AT), glucose intolerance, and enhanced progression to steatohepatitis resulting from B7.1/B7.2 double deficiency. The metabolic phenotype of B7.1/B7.2 double deficiency upon DIO was accompanied by increased hepatic and AT inflammation, associated with largely reduced numbers of regulatory T cells (Tregs) in these organs. In order to assess the role of B7 costimulation in DIO in a non-Treg-lacking environment, we performed antibody (Ab)-mediated inhibition of B7 molecules in wild-type mice in DIO. Antibody-blockade of both B7.1 and B7.2 improved the metabolic phenotype of DIO mice, which was linked to amelioration of hepatic steatosis and reduced inflammation in liver and AT. CONCLUSION: Our study demonstrates a dual role of B7 costimulation in the course of obesity-related sequelae, particularly NASH. The genetic inactivation of B7.1/B7.2 deteriorates obesity-related liver steatosis and metabolic dysregulation, likely a result of the intrinsic absence of Tregs in these mice, rendering DKO mice a novel murine model of NASH. In contrast, inhibition of B7 costimulation under conditions where Tregs are present may provide a novel therapeutic approach for obesity-related metabolic dysregulation and, especially, NASH.
Asunto(s)
Antígenos B7/fisiología , Síndrome Metabólico/fisiopatología , Enfermedad del Hígado Graso no Alcohólico/fisiopatología , Obesidad/fisiopatología , Animales , Antígenos B7/deficiencia , Antígenos B7/genética , Comunicación Celular/fisiología , Modelos Animales de Enfermedad , Hígado/patología , Masculino , Ratones , Ratones Noqueados , Fenotipo , Linfocitos T Reguladores/patologíaRESUMEN
Obese adipose tissue (AT) inflammation contributes critically to development of insulin resistance. The complement anaphylatoxin C5a receptor (C5aR) has been implicated in inflammatory processes and as regulator of macrophage activation and polarization. However, the role of C5aR in obesity and AT inflammation has not been addressed. We engaged the model of diet-induced obesity and found that expression of C5aR was significantly upregulated in the obese AT, compared with lean AT. In addition, C5a was present in obese AT in the proximity of macrophage-rich crownlike structures. C5aR-sufficient and -deficient mice were fed a high-fat diet (HFD) or a normal diet (ND). C5aR deficiency was associated with increased AT weight upon ND feeding in males, but not in females, and with increased adipocyte size upon ND and HFD conditions in males. However, obese C5aR(-/-) mice displayed improved systemic and AT insulin sensitivity. Improved AT insulin sensitivity in C5aR(-/-) mice was associated with reduced accumulation of total and proinflammatory M1 macrophages in the obese AT, increased expression of IL-10, and decreased AT fibrosis. In contrast, no difference in ß cell mass was observed owing to C5aR deficiency under an HFD. These results suggest that C5aR contributes to macrophage accumulation and M1 polarization in the obese AT and thereby to AT dysfunction and development of AT insulin resistance.
Asunto(s)
Tejido Adiposo/inmunología , Tejido Adiposo/metabolismo , Resistencia a la Insulina/inmunología , Macrófagos/inmunología , Receptor de Anafilatoxina C5a/metabolismo , Adipocitos/inmunología , Adipocitos/metabolismo , Animales , Complemento C5a/metabolismo , Grasas de la Dieta/inmunología , Grasas de la Dieta/metabolismo , Femenino , Fibrosis/inmunología , Inflamación/inmunología , Células Secretoras de Insulina/metabolismo , Interleucina-10/biosíntesis , Activación de Macrófagos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/inmunología , Obesidad/metabolismo , Receptor de Anafilatoxina C5a/biosíntesis , Receptor de Anafilatoxina C5a/inmunología , Regulación hacia ArribaRESUMEN
Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing chromaffin cell tumors with diverse phenotypic features reflecting mutations in numerous genes, including MYC-associated factor X (MAX). To explore whether phenotypic differences among PPGLs reflect a MAX-mediated mechanism and opposing influences of hypoxia-inducible factor (HIF)s HIF2α and HIF1α, we combined observational investigations in PPGLs and gene-manipulation studies in two pheochromocytoma cell lines. Among PPGLs from 140 patients, tumors due to MAX mutations were characterized by gene expression profiles and intermediate phenotypic features that distinguished these tumors from other PPGLs, all of which fell into two expression clusters: one cluster with low expression of HIF2α and mature phenotypic features and the other with high expression of HIF2α and immature phenotypic features due to mutations stabilizing HIFs. Max-mutated tumors distributed to a distinct subcluster of the former group. In cell lines lacking Max, re-expression of the gene resulted in maturation of phenotypic features and decreased cell cycle progression. In cell lines lacking Hif2α, overexpression of the gene led to immature phenotypic features, failure of dexamethasone to induce differentiation and increased proliferation. HIF1α had opposing actions to HIF2α in both cell lines, supporting evolving evidence of their differential actions on tumorigenic processes via a MYC/MAX-related pathway. Requirement of a fully functional MYC/MAX complex to facilitate differentiation explains the intermediate phenotypic features in tumors due to MAX mutations. Overexpression of HIF2α in chromaffin cell tumors due to mutations affecting HIF stabilization explains their proliferative features and why the tumors fail to differentiate even when exposed locally to adrenal steroids.
Asunto(s)
Neoplasias de las Glándulas Suprarrenales/patología , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Biomarcadores de Tumor/metabolismo , Proliferación Celular , Células Cromafines/patología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Paraganglioma/patología , Feocromocitoma/patología , Neoplasias de las Glándulas Suprarrenales/genética , Neoplasias de las Glándulas Suprarrenales/metabolismo , Animales , Apoptosis , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Biomarcadores de Tumor/genética , Western Blotting , Ciclo Celular , Diferenciación Celular , Células Cromafines/metabolismo , Perfilación de la Expresión Génica , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Mutación/genética , Paraganglioma/genética , Paraganglioma/metabolismo , Feocromocitoma/genética , Feocromocitoma/metabolismo , ARN Mensajero/genética , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales CultivadasRESUMEN
Tissues release microRNAs (miRNAs) in small extracellular vesicles (sEVs) including exosomes, which can regulate gene expression in distal cells, thus acting as modulators of local and systemic metabolism. Here, we show that insulin regulates miRNA secretion into sEVs from 3T3-L1 adipocytes and that this process is differentially regulated from cellular expression. Thus, of the 53 miRNAs upregulated and 66 miRNAs downregulated by insulin in 3T3-L1 sEVs, only 12 were regulated in parallel in cells. Insulin regulated this process in part by phosphorylating hnRNPA1, causing it to bind to AU-rich motifs in miRNAs, mediating their secretion into sEVs. Importantly, 43% of insulin-regulated sEV-miRNAs are implicated in obesity and insulin resistance. These include let-7 and miR-103, which we show regulate insulin signaling in AML12 hepatocytes. Together, these findings demonstrate an important layer to insulin's regulation of adipose biology and provide a mechanism of tissue crosstalk in obesity and other hyperinsulinemic states.
Asunto(s)
Vesículas Extracelulares , Insulina , MicroARNs , Animales , Humanos , Ratones , Células 3T3-L1 , Adipocitos/metabolismo , Adipocitos/efectos de los fármacos , Vesículas Extracelulares/metabolismo , Regulación de la Expresión Génica , Hepatocitos/metabolismo , Ribonucleoproteína Nuclear Heterogénea A1/metabolismo , Ribonucleoproteína Nuclear Heterogénea A1/genética , Insulina/metabolismo , Resistencia a la Insulina , MicroARNs/metabolismo , MicroARNs/genética , Obesidad/metabolismo , Obesidad/genética , Fosforilación , Transducción de SeñalRESUMEN
Oxidative stress-induced myocardial apoptosis and necrosis are critically involved in ischemic infarction, and several sources of extracellular vesicles appear to be enriched in therapeutic activities. The central objective was to identify and validate the differential exosome miRNA repertoire in human cardiac progenitor cells (CPC). CPC exosomes were first analyzed by LC-MS/MS and compared by RNAseq with exomes of human mesenchymal stromal cells and human fibroblasts to define their differential exosome miRNA repertoire (exo-miRSEL). Proteomics demonstrated a highly significant representation of cardiovascular development functions and angiogenesis in CPC exosomes, and RNAseq analysis yielded about 350 different miRNAs; among the exo-miRSEL population, miR-935 was confirmed as the miRNA most significantly up-regulated; interestingly, miR-935 was also found to be preferentially expressed in mouse primary cardiac Bmi1+high CPC, a population highly enriched in progenitors. Furthermore, it was found that transfection of an miR-935 antagomiR combined with oxidative stress treatment provoked a significant increment both in apoptotic and necrotic populations, whereas transfection of a miR-935 mimic did not modify the response. Conclusion. miR-935 is a highly differentially expressed miRNA in exo-miRSEL, and its expression reduction promotes oxidative stress-associated apoptosis. MiR-935, together with other exosomal miRNA members, could counteract oxidative stress-related apoptosis, at least in CPC surroundings.
RESUMEN
Exosomes/small extracellular vesicles (sEVs) can serve as multifactorial mediators of cell-to-cell communication through their miRNA and protein cargo. Quantitative proteomic analysis of five cell lines representing metabolically important tissues reveals that each cell type has a unique sEV proteome. While classical sEV markers such as CD9/CD63/CD81 vary markedly in abundance, we identify six sEV markers (ENO1, GPI, HSPA5, YWHAB, CSF1R, and CNTN1) that are similarly abundant in sEVs of all cell types. In addition, each cell type has specific sEV markers. Using fat-specific Dicer-knockout mice with decreased white adipose tissue and increased brown adipose tissue, we show that these cell-type-specific markers can predict the changing origin of the serum sEVs. These results provide a valuable resource for understanding the sEV proteome of the cells and tissues important in metabolic homeostasis, identify unique sEV markers, and demonstrate how these markers can help in predicting the tissue of origin of serum sEVs.
Asunto(s)
Biomarcadores/sangre , Exosomas/metabolismo , Proteoma/metabolismo , Células 3T3 , Adiponectina/sangre , Tejido Adiposo/metabolismo , Animales , RatonesRESUMEN
We identified a microRNA (miRNA) profile characterizing HIV lipodystrophy and explored the downstream mechanistic implications with respect to adipocyte biology and the associated clinical phenotype. miRNA profiles were extracted from small extracellular vesicles (sEVs) of HIV-infected individuals with and without lipodystrophic changes and individuals without HIV, among whom we previously showed significant reductions in adipose Dicer expression related to HIV. miR-20a-3p was increased and miR-324-5p and miR-186 were reduced in sEVs from HIV lipodystrophic individuals. Changes in these miRNAs correlated with adipose Dicer expression and clinical markers of lipodystrophy, including fat redistribution, insulin resistance, and hypertriglyceridemia. Human preadipocytes transfected with mimic miR-20a-3p, anti-miR-324-5p, or anti-miR-186 induced consistent changes in latent transforming growth factor beta binding protein 2 (Ltbp2), Wisp2, and Nebl expression. Knockdown of Ltbp2 downregulated markers of adipocyte differentiation (Fabp4, Pparγ, C/ebpa, Fasn, adiponectin, Glut4, CD36), and Lamin C, and increased expression of genes involved in inflammation (IL1ß, IL6, and Ccl20). Our studies suggest a likely unique sEV miRNA signature related to dysregulation of Dicer in adipose tissue in HIV. Enhanced miR-20a-3p or depletion of miR-186 and miR-324-5p may downregulate Ltbp2 in HIV, leading to dysregulation in adipose differentiation and inflammation, which could contribute to acquired HIV lipodystrophy and associated metabolic and inflammatory perturbations.
Asunto(s)
Tejido Adiposo/metabolismo , ARN Helicasas DEAD-box/metabolismo , Síndrome de Lipodistrofia Asociada a VIH/sangre , MicroARNs/sangre , MicroARNs/genética , Ribonucleasa III/metabolismo , Adipocitos/fisiología , Adipogénesis , Adiposidad , Adolescente , Adulto , Animales , Proteínas CCN de Señalización Intercelular/genética , Proteínas Portadoras/genética , Diferenciación Celular/genética , Proteínas del Citoesqueleto/genética , ARN Helicasas DEAD-box/genética , Regulación hacia Abajo , Vesículas Extracelulares/metabolismo , Femenino , Silenciador del Gen , Humanos , Inflamación/genética , Resistencia a la Insulina , Proteínas con Dominio LIM/genética , Proteínas de Unión a TGF-beta Latente/genética , Masculino , Células Madre Mesenquimatosas/fisiología , Ratones , Ratones Noqueados , Persona de Mediana Edad , Proteínas Represoras/genética , Ribonucleasa III/genética , Adulto JovenRESUMEN
The brain is now recognized as an insulin-sensitive tissue; however, the role of changing insulin concentrations in the peripheral circulation in gene expression in the brain is largely unknown. Here, we performed a hyperinsulinemic-euglycemic clamp on 3-month-old male C57BL/6 mice for 3 h. We show that, in comparison with results in saline-infused controls, increases in peripheral insulin within the physiological range regulate expression of a broad network of genes in the brain. Insulin regulates distinct pathways in the hypothalamus (HTM), hippocampus, and nucleus accumbens. Insulin shows its most robust effect in the HTM and regulates multiple genes involved in neurotransmission, including upregulating expression of multiple subunits of GABA-A receptors, Na+ and K+ channels, and SNARE proteins; differentially modulating glutamate receptors; and suppressing multiple neuropeptides. Insulin also strongly modulates metabolic genes in the HTM, suppressing genes in the glycolysis and pentose phosphate pathways, while increasing expression of genes regulating pyruvate dehydrogenase and long-chain fatty acyl-CoA and cholesterol biosynthesis, thereby rerouting of carbon substrates from glucose metabolism to lipid metabolism required for the biogenesis of membranes for neuronal and glial function and synaptic remodeling. Furthermore, based on the transcriptional signatures, these changes in gene expression involve neurons, astrocytes, oligodendrocytes, microglia, and endothelial cells. Thus, peripheral insulin acutely and potently regulates expression of a broad network of genes involved in neurotransmission and brain metabolism. Dysregulation of these pathways could have dramatic effects in normal physiology and diabetes.
Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Hipocampo/metabolismo , Hipotálamo/metabolismo , Insulina/farmacología , Lipogénesis/fisiología , Núcleo Accumbens/metabolismo , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Técnica de Clampeo de la Glucosa , Hipocampo/efectos de los fármacos , Hipotálamo/efectos de los fármacos , Lipogénesis/efectos de los fármacos , Masculino , Ratones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Núcleo Accumbens/efectos de los fármacosRESUMEN
miRNAs can be found in serum and other body fluids and serve as biomarkers for disease. More importantly, secreted miRNAs, especially those in extracellular vesicles (EVs) such as exosomes, may mediate paracrine and endocrine communication between different tissues and thus modulate gene expression and the function of distal cells. When impaired, these processes can lead to tissue dysfunction, aging, and disease. Adipose tissue is an especially important contributor to the pool of circulating exosomal miRNAs. As a result, alterations in adipose tissue mass or function, which occur in many metabolic conditions, can lead to changes in circulating miRNAs, which then function systemically. Here we review the findings that led to these conclusions and discuss how this sets the stage for new lines of investigation in which extracellular miRNAs are recognized as important mediators of intercellular communication and potential candidates for therapy of disease.