Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60.583
Filtrar
1.
Rev Assoc Med Bras (1992) ; 66(9): 1235-1240, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33027451

RESUMO

INTRODUCTION: Sarcopenia is characterized by the involuntary loss of lean body mass associated with a progressive reduction of muscle strength. OBJECTIVE: To determine the prevalence of sarcopenia in kidney transplant recipients and its association with the determining factors that control muscle homeostasis. METHODS: We evaluated renal transplant recipients undergoing follow-up at the University Hospital of the Federal University of Maranhão from June 2017 to July 2018 and who met the inclusion criteria. Sarcopenia was defined according to the European criteria. The skeletal muscle mass index was measured by dual-energy radiological absorptiometry; the values <7,26 kg/m2 for men and <5,5 kg/m2 for women were adopted for muscle depletion. For handgrip strength, values of <30 kg for men and <20 kg for women were considered as reduced muscle strength. In both sexes, the cutoff point for walking speed was <0,8 m/s. RESULTS: We evaluated 83 renal transplant recipients with a mean age of 48.8 ± 12,1 years and predominantly males (57,8%). The prevalence of sarcopenia was 19,3%. Among individuals without sarcopenia, 17,9% had a decrease in handgrip strength and 40,3% has altered gait speed. DISCUSSION: Individuals submitted to renal transplant may develop sarcopenia while still young and already present altered muscle function and strength even before the depletion of lean body mass. CONCLUSION: Early diagnosis may allow the prevention of sarcopenia and provide a better quality of life for patients.


Assuntos
Transplante de Rim , Sarcopenia , Adulto , Feminino , Força da Mão , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Qualidade de Vida
2.
Yakugaku Zasshi ; 140(10): 1207-1212, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32999199

RESUMO

T-type calcium channels are low-threshold voltage-gated calcium channel and characterized by unique electrophysiological properties such as fast inactivation and slow deactivation kinetics. All subtypes of T-type calcium channel (Cav3.1, 3.2 and 3.3) are widely expressed in the central nerve system, and they have an important role in homeostasis of sleep, pain response, and development of epilepsy. Recently, several reports suggest that T-type calcium channels may mediate neuronal plasticity in the mouse brain. We succeeded to develop T-type calcium channel enhancer ethyl 8'-methyl-2',4-dioxo-2-(piperidin-1-yl)-2'H-spiro[cyclopentane-1,3'-imidazo[1,2-a]pyridine]-2-ene-3-carboxylate (SAK3) which enhances Cav3.1 and 3.3 currents in each-channel expressed neuro2A cells. SAK3 can promote acetylcholine (ACh) release in the mouse hippocampus via enhancing T-type calcium channel. In this review, we have introduced the role of T-type calcium channel, especially Cav3.1 channel in the mouse hippocampus based on our previous data using SAK3 and Cav3.1 knockout mice.


Assuntos
Canais de Cálcio Tipo T/efeitos dos fármacos , Canais de Cálcio Tipo T/fisiologia , Imidazóis/farmacologia , Neurônios/fisiologia , Compostos de Espiro/farmacologia , Acetilcolina/metabolismo , Animais , Encéfalo/fisiologia , Canais de Cálcio Tipo T/genética , Canais de Cálcio Tipo T/metabolismo , Células Cultivadas , Sistema Nervoso Central/metabolismo , Fenômenos Eletrofisiológicos , Epilepsia/etiologia , Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Homeostase , Camundongos , Plasticidade Neuronal , Dor/etiologia , Ratos , Sono/fisiologia
6.
Nat Commun ; 11(1): 4718, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32948777

RESUMO

Disturbances in glucose homeostasis and low-grade chronic inflammation culminate into metabolic syndrome that increase the risk for the development of type 2 diabetes mellitus (T2DM). The recently discovered group 2 innate lymphoid cells (ILC2s) are capable of secreting copious amounts of type 2 cytokines to modulate metabolic homeostasis in adipose tissue. In this study, we have established that expression of Death Receptor 3 (DR3), a member of the TNF superfamily, on visceral adipose tissue (VAT)-derived murine and peripheral blood human ILC2s is inducible by IL-33. We demonstrate that DR3 engages the canonical and/or non-canonical NF-κB pathways, and thus stimulates naïve and co-stimulates IL-33-activated ILC2s. Importantly, DR3 engagement on ILC2s significantly ameliorates glucose tolerance, protects against insulin-resistance onset and remarkably reverses already established insulin-resistance. Taken together, these results convey the potent role of DR3 as an ILC2 regulator and introduce DR3 agonistic treatment as a novel therapeutic avenue for treating T2DM.


Assuntos
Tecido Adiposo/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Linfócitos/metabolismo , Membro 25 de Receptores de Fatores de Necrose Tumoral/metabolismo , Adipócitos/metabolismo , Adolescente , Adulto , Idoso , Animais , Citocinas/metabolismo , Proteínas de Ligação a DNA/genética , Feminino , Glucose/metabolismo , Homeostase , Humanos , Imunidade Inata , Resistência à Insulina , Interleucina-33/metabolismo , Gordura Intra-Abdominal/metabolismo , Masculino , Síndrome Metabólica/complicações , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Membro 25 de Receptores de Fatores de Necrose Tumoral/uso terapêutico , Adulto Jovem
7.
Wei Sheng Yan Jiu ; 49(4): 527-533, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928343

RESUMO

OBJECTIVE: To explore the effect of combined oral exposure of titanium dioxide nanoparticles(TiO_2 NPs) and glucose on blood glucose homeostasis in young SD rats. METHODS: Eighty 4-week-old young SD rats were randomly divided into 8 groups(10 rats in each group, half male and half female). The rats were exposed to TiO_2 NPs through intragastric administration at 0, 2, 10 and 50 mg/kg with or without 1. 8 g/kg glucose daily for 30 days. Blood glucose was monitored weekly during the experiment. Oral glucose tolerance test(OGTT) was carried out after subacute exposure(30 days), and the biomarkers related to blood glucose homeostasis were detected, including the contents of glycosylated serum protein(GSP), glycosylated hemoglobin(HbA1 c), insulin, C-peptide and glucagon. At the same time, the pancreatic pathology of rats was observed. RESULTS: TiO_2 NPs were anatase crystals, closely spherical shape, with an average particle size of(24±5)nm. Exposure of TiO_2 NPs alone had little effect on blood glucose homeostasis. Blood glucose decreased on the 16 th exposure day at dose of 10 mg/kg TiO_2 NPs, and postprandial blood glucose(2 h) decreased after 30 days of TiO_2 NPs exposure at doses of 2 and 50 mg/kg in male rats(P<0. 05). The combined effect of oral exposure of TiO_2 NPs and glucose on blood glucose homeostasis was more obvious than that of TiO_2 NPs alone. Blood glucose decreased on the 9 th exposure day at dose of 10 mg/kg TiO_2 NPs+glucose in female rats, and postprandial blood glucose(2 h) decreased at dose of 2 and 50 mg/kg TiO_2 NPs+glucose after 30 days of exposure in male rats(P<0. 05). Blood glucose decreased on the 9 th day after 10 mg/kg TiO_2 NPs+glucose exposure in female rats. The glycosylated serum protein decreased and postprandial blood glucose(30 and 60 min) as well as the area under curve of OGTT increased in male rats after 30 days of exposure(P<0. 05). The changes of blood glucose-regulating hormones were only found after the combined exposure of 10 mg/kg TiO_2 NPs+glucose for 30 days, including the decrease of insulin in female rats, as well as the decrease of insulin and the increase of glucagon in male rats(P<0. 05). The interaction analysis showed that TiO_2 NPs and glucose had significant synergistic effect on postprandial blood glucose(60 min) in male rats(P<0. 05). No abnormality was found in the pathological observation of pancreas in rats of experimental groups. CONCLUSION: Subacute combined oral exposure of TiO_2 NPs and glucose could affect the blood glucose homeostasis of young SD rats, resultsing in temporary hypoglycemia and impaired glucose tolerance, as well as adaptive changes of blood glucose-regulating hormones. The male rats were more sensitive. Compared with the exposure of TiO_2 NPs alone, the combined exposure of TiO_2 NPs and glucose induced more significant effects. Significant synergistic effect between them occurred on postprandial blood glucose.


Assuntos
Glicemia , Nanopartículas , Animais , Feminino , Glucose , Homeostase , Masculino , Ratos , Ratos Sprague-Dawley , Titânio
8.
Crit Care Resusc ; 22(3): 257-265, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32900333

RESUMO

Albumin is the most abundant and perhaps most important protein in human blood. Research has identified many of albumin's possible roles in modulating acid-base balance, modifying inflammation, maintaining vascular endothelial integrity, and binding endogenous and exogenous compounds. Albumin plays a key role in the homeostasis of vascular endothelium, offering protection from inflammation and damage to the glycocalyx. Albumin binds a diverse range of compounds. It transports, delivers and clears drugs, plus it helps with uptake, storage and disposal of potentially harmful biological products. The biological effects of albumin in critical illness are incompletely understood, but may enhance its clinical role beyond use as an intravenous fluid. In this article, we summarise the evidence surrounding albumin's biological and physiological effects beyond its use for plasma volume expansion, and explore potential mechanistic effects of albumin as a disease modifier in patients with critical illness.


Assuntos
Albuminas/farmacologia , Endotélio Vascular/efeitos dos fármacos , Glicocálix , Células Endoteliais/metabolismo , Homeostase , Humanos
9.
Nat Commun ; 11(1): 4549, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917889

RESUMO

Arterial macrophages have different developmental origins, but the association of macrophage ontogeny with their phenotypes and functions in adulthood is still unclear. Here, we combine macrophage fate-mapping analysis with single-cell RNA sequencing to establish their cellular identity during homeostasis, and in response to angiotensin-II (AngII)-induced arterial inflammation. Yolk sac erythro-myeloid progenitors (EMP) contribute substantially to adventitial macrophages and give rise to a defined cluster of resident immune cells with homeostatic functions that is stable in adult mice, but declines in numbers during ageing and is not replenished by bone marrow (BM)-derived macrophages. In response to AngII inflammation, increase in adventitial macrophages is driven by recruitment of BM monocytes, while EMP-derived macrophages proliferate locally and provide a distinct transcriptional response that is linked to tissue regeneration. Our findings thus contribute to the understanding of macrophage heterogeneity, and associate macrophage ontogeny with distinct functions in health and disease.


Assuntos
Artérias/citologia , Arterite/imunologia , Diferenciação Celular/fisiologia , Homeostase/fisiologia , Macrófagos/fisiologia , Envelhecimento/fisiologia , Angiotensina II/administração & dosagem , Angiotensina II/imunologia , Animais , Artérias/fisiologia , Medula Óssea/fisiologia , Transplante de Medula Óssea , Linhagem da Célula , Modelos Animais de Doenças , Feminino , Células-Tronco Hematopoéticas/fisiologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , RNA-Seq , Regeneração/fisiologia , Análise de Célula Única , Quimeras de Transplante
10.
Nat Commun ; 11(1): 4866, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978391

RESUMO

Mitochondria house evolutionarily conserved pathways of carbon and nitrogen metabolism that drive cellular energy production. Mitochondrial bioenergetics is regulated by calcium uptake through the mitochondrial calcium uniporter (MCU), a multi-protein complex whose assembly in the inner mitochondrial membrane is facilitated by the scaffold factor MCUR1. Intriguingly, many fungi that lack MCU contain MCUR1 homologs, suggesting alternate functions. Herein, we characterize Saccharomyces cerevisiae homologs Put6 and Put7 of MCUR1 as regulators of mitochondrial proline metabolism. Put6 and Put7 are tethered to the inner mitochondrial membrane in a large hetero-oligomeric complex, whose abundance is regulated by proline. Loss of this complex perturbs mitochondrial proline homeostasis and cellular redox balance. Yeast cells lacking either Put6 or Put7 exhibit a pronounced defect in proline utilization, which can be corrected by the heterologous expression of human MCUR1. Our work uncovers an unexpected role of MCUR1 homologs in mitochondrial proline metabolism.


Assuntos
Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Prolina/metabolismo , Saccharomyces cerevisiae/metabolismo , Canais de Cálcio , Regulação Fúngica da Expressão Gênica , Genes Fúngicos/genética , Homeostase , Humanos , Proteínas de Membrana/genética , Redes e Vias Metabólicas/genética , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Transcriptoma
11.
Nat Commun ; 11(1): 4755, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958772

RESUMO

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O2 in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance.


Assuntos
Homeostase , Oxigênio/metabolismo , RNA Longo não Codificante/fisiologia , Esteróis/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Colesterol/metabolismo , Estrogênios/metabolismo , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Humanos , Células MCF-7 , Fenótipo , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
12.
Med Sci Monit ; 26: e926178, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32978363

RESUMO

BACKGROUND The aim of this study was to assess the diagnostic utility of iron homeostasis determinations for prediction of severity of COVID-19. MATERIAL AND METHODS This was a retrospective study enrolling a total of 50 patients diagnosed with the novel coronavirus disease-19 (COVID-19) from February 27, 2020 to March 30, 2020, including a severe group (12 patients) and a mild group (38 patients). For the control group, 50 healthy people were examined during the same period. We compared clinical laboratory data and iron homeostasis biomarkers among the 3 groups. ROC curve analysis was used to assess diagnoses. RESULTS Patients diagnosed with severe COVID-19 had higher hepcidin and serum ferritin levels than in other groups (p<0.001). A combination test of hepcidin and serum ferritin provided the best specificity and sensitivity in the prognosis of COVID-19 severity. Logistic regression analysis showed hepcidin and serum ferritin independently contributed to the severity of COVID-19. Hepcidin and serum ferritin tandem testing predicted COVID-19 severity with 94.6% specificity, while hepcidin and serum ferritin parallel testing had a sensitivity of 95.7%. CONCLUSIONS Iron homeostasis had a robust association with the occurrence of severe COVID-19. Iron homeostasis determinations were specific and sensitive for the early prediction of disease severity in COVID-19 patients and thus have clinical utility.


Assuntos
Betacoronavirus , Infecções por Coronavirus/sangue , Ferritinas/sangue , Hepcidinas/sangue , Pandemias , Pneumonia Viral/sangue , Adulto , Idoso , Área Sob a Curva , Biomarcadores , Feminino , Homeostase , Humanos , Ferro/metabolismo , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prognóstico , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade
14.
Front Immunol ; 11: 1712, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32754164

RESUMO

During the current corona pandemic, new therapeutic options against this viral disease are urgently desired. Due to the rapid spread and immense number of affected individuals worldwide, cost-effective, globally available, and safe options with minimal side effects and simple application are extremely warranted. This review will therefore discuss the potential of zinc as preventive and therapeutic agent alone or in combination with other strategies, as zinc meets all the above described criteria. While a variety of data on the association of the individual zinc status with viral and respiratory tract infections are available, study evidence regarding COVID-19 is so far missing but can be assumed as was indicated by others and is detailed in this perspective, focusing on re-balancing of the immune response by zinc supplementation. Especially, the role of zinc in viral-induced vascular complications has barely been discussed, so far. Interestingly, most of the risk groups described for COVID-19 are at the same time groups that were associated with zinc deficiency. As zinc is essential to preserve natural tissue barriers such as the respiratory epithelium, preventing pathogen entry, for a balanced function of the immune system and the redox system, zinc deficiency can probably be added to the factors predisposing individuals to infection and detrimental progression of COVID-19. Finally, due to its direct antiviral properties, it can be assumed that zinc administration is beneficial for most of the population, especially those with suboptimal zinc status.


Assuntos
Antivirais/imunologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Suplementos Nutricionais , Pandemias/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Zinco/imunologia , Animais , Antivirais/farmacologia , Antivirais/uso terapêutico , Cílios/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Homeostase/imunologia , Humanos , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Mucosa Respiratória/imunologia , Internalização do Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Zinco/deficiência , Zinco/farmacologia , Zinco/uso terapêutico
16.
Cells ; 9(9)2020 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-32847034

RESUMO

The preservation of cellular homeostasis requires the synthesis of new proteins (proteostasis) and organelles, and the effective removal of misfolded or impaired proteins and cellular debris. This cellular homeostasis involves two key proteostasis mechanisms, the ubiquitin proteasome system and the autophagy-lysosome pathway. These catabolic pathways have been known to be involved in respiratory exacerbations and the pathogenesis of various lung diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF), acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and coronavirus disease-2019 (COVID-19). Briefly, proteostasis and autophagy processes are known to decline over time with age, cigarette or biomass smoke exposure, and/or influenced by underlying genetic factors, resulting in the accumulation of misfolded proteins and cellular debris, elevating apoptosis and cellular senescence, and initiating the pathogenesis of acute or chronic lung disease. Moreover, autophagic dysfunction results in an impaired microbial clearance, post-bacterial and/or viral infection(s) which contribute to the initiation of acute and recurrent respiratory exacerbations as well as the progression of chronic obstructive and restrictive lung diseases. In addition, the autophagic dysfunction-mediated cystic fibrosis transmembrane conductance regulator (CFTR) immune response impairment further exacerbates the lung disease. Recent studies demonstrate the therapeutic potential of novel autophagy augmentation strategies, in alleviating the pathogenesis of chronic obstructive or restrictive lung diseases and exacerbations such as those commonly seen in COPD, CF, ALI/ARDS and COVID-19.


Assuntos
Autofagia/imunologia , Betacoronavirus , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/metabolismo , Progressão da Doença , Pneumonia Viral/imunologia , Pneumonia Viral/metabolismo , Lesão Pulmonar Aguda/imunologia , Lesão Pulmonar Aguda/metabolismo , Infecções por Coronavirus/virologia , Fibrose Cística/imunologia , Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Homeostase , Humanos , Fibrose Pulmonar Idiopática/imunologia , Fibrose Pulmonar Idiopática/metabolismo , Lisossomos/metabolismo , Pandemias , Pneumonia Viral/virologia , Doença Pulmonar Obstrutiva Crônica/imunologia , Doença Pulmonar Obstrutiva Crônica/metabolismo , Síndrome do Desconforto Respiratório do Adulto/imunologia , Síndrome do Desconforto Respiratório do Adulto/metabolismo
17.
Nat Commun ; 11(1): 4071, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792491

RESUMO

Arrest of oligodendrocyte (OL) differentiation and remyelination following myelin damage in multiple sclerosis (MS) is associated with neurodegeneration and clinical worsening. We show that Glutathione S-transferase 4α (Gsta4) is highly expressed during adult OL differentiation and that Gsta4 loss impairs differentiation into myelinating OLs in vitro. In addition, we identify Gsta4 as a target of both dimethyl fumarate, an existing MS therapy, and clemastine fumarate, a candidate remyelinating agent in MS. Overexpression of Gsta4 reduces expression of Fas and activity of the mitochondria-associated Casp8-Bid-axis in adult oligodendrocyte precursor cells, leading to improved OL survival during differentiation. The Gsta4 effect on apoptosis during adult OL differentiation was corroborated in vivo in both lysolecithin-induced demyelination and experimental autoimmune encephalomyelitis models, where Casp8 activity was reduced in Gsta4-overexpressing OLs. Our results identify Gsta4 as an intrinsic regulator of OL differentiation, survival and remyelination, as well as a potential target for future reparative MS therapies.


Assuntos
Glutationa Transferase/metabolismo , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Animais , Apoptose/genética , Apoptose/fisiologia , Caspase 8/genética , Caspase 8/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Glutationa Transferase/genética , Homeostase/genética , Homeostase/fisiologia , Imuno-Histoquímica , Masculino , Microglia/citologia , Microglia/metabolismo , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo , Esclerose Múltipla/genética , Esclerose Múltipla/metabolismo , Fagocitose/genética , Fagocitose/fisiologia , Processamento de Proteína Pós-Traducional , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Remielinização/genética , Remielinização/fisiologia
18.
Nat Commun ; 11(1): 3798, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732867

RESUMO

Blood vascular endothelial cells (BECs) control the immune response by regulating blood flow and immune cell recruitment in lymphoid tissues. However, the diversity of BEC and their origins during immune angiogenesis remain unclear. Here we profile transcriptomes of BEC from peripheral lymph nodes and map phenotypes to the vasculature. We identify multiple subsets, including a medullary venous population whose gene signature predicts a selective role in myeloid cell (vs lymphocyte) recruitment to the medulla, confirmed by videomicroscopy. We define five capillary subsets, including a capillary resident precursor (CRP) that displays stem cell and migratory gene signatures, and contributes to homeostatic BEC turnover and to neogenesis of high endothelium after immunization. Cell alignments show retention of developmental programs along trajectories from CRP to mature venous and arterial populations. Our single cell atlas provides a molecular roadmap of the lymph node blood vasculature and defines subset specialization for leukocyte recruitment and vascular homeostasis.


Assuntos
Células Endoteliais/citologia , Endotélio Vascular/citologia , Linfonodos/irrigação sanguínea , Linfócitos/imunologia , Células Mieloides/imunologia , Animais , Sequência de Bases , Movimento Celular/imunologia , Feminino , Perfilação da Expressão Gênica , Homeostase/imunologia , Inflamação/imunologia , Tecido Linfoide/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Análise de Sequência de RNA , Análise de Célula Única , Transcriptoma/genética
19.
Nat Commun ; 11(1): 3822, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732898

RESUMO

Alveolar macrophages (AMs) derived from embryonic precursors seed the lung before birth and self-maintain locally throughout adulthood, but are regenerated by bone marrow (BM) under stress conditions. However, the regulation of AM development and maintenance remains poorly understood. Here, we show that histone deacetylase 3 (HDAC3) is a key epigenetic factor required for AM embryonic development, postnatal homeostasis, maturation, and regeneration from BM. Loss of HDAC3 in early embryonic development affects AM development starting at E14.5, while loss of HDAC3 after birth affects AM homeostasis and maturation. Single-cell RNA sequencing analyses reveal four distinct AM sub-clusters and a dysregulated cluster-specific pathway in the HDAC3-deficient AMs. Moreover, HDAC3-deficient AMs exhibit severe mitochondrial oxidative dysfunction and deteriorative cell death. Mechanistically, HDAC3 directly binds to Pparg enhancers, and HDAC3 deficiency impairs Pparg expression and its signaling pathway. Our findings identify HDAC3 as a key epigenetic regulator of lung AM development and homeostasis.


Assuntos
Histona Desacetilases/genética , Homeostase/genética , Pulmão/metabolismo , Macrófagos Alveolares/metabolismo , Animais , Apoptose/genética , Diferenciação Celular/genética , Linhagem Celular , Células Cultivadas , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica no Desenvolvimento , Ontologia Genética , Histona Desacetilases/deficiência , Histona Desacetilases/metabolismo , Pulmão/embriologia , Pulmão/crescimento & desenvolvimento , Macrófagos Alveolares/citologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos
20.
PLoS Comput Biol ; 16(8): e1008118, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32764742

RESUMO

Hebbian plasticity, a mechanism believed to be the substrate of learning and memory, detects and further enhances correlated neural activity. Because this constitutes an unstable positive feedback loop, it requires additional homeostatic control. Computational work suggests that in recurrent networks, the homeostatic mechanisms observed in experiments are too slow to compensate instabilities arising from Hebbian plasticity and need to be complemented by rapid compensatory processes. We suggest presynaptic inhibition as a candidate that rapidly provides stability by compensating recurrent excitation induced by Hebbian changes. Presynaptic inhibition is mediated by presynaptic GABA receptors that effectively and reversibly attenuate transmitter release. Activation of these receptors can be triggered by excess network activity, hence providing a stabilising negative feedback loop that weakens recurrent interactions on sub-second timescales. We study the stabilising effect of presynaptic inhibition in recurrent networks, in which presynaptic inhibition is implemented as a multiplicative reduction of recurrent synaptic weights in response to increasing inhibitory activity. We show that networks with presynaptic inhibition display a gradual increase of firing rates with growing excitatory weights, in contrast to traditional excitatory-inhibitory networks. This alleviates the positive feedback loop between Hebbian plasticity and network activity and thereby allows homeostasis to act on timescales similar to those observed in experiments. Our results generalise to spiking networks with a biophysically more detailed implementation of the presynaptic inhibition mechanism. In conclusion, presynaptic inhibition provides a powerful compensatory mechanism that rapidly reduces effective recurrent interactions and thereby stabilises Hebbian learning.


Assuntos
Modelos Neurológicos , Inibição Neural/fisiologia , Plasticidade Neuronal/fisiologia , Sinapses/fisiologia , Animais , Biologia Computacional , Homeostase , Aprendizagem , Memória , Neurônios/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA