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1.
Annu Rev Cell Dev Biol ; 32: 649-675, 2016 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-27576121

RESUMO

In addition to their conventional role as a versatile transport system, blood vessels provide signals controlling organ development, regeneration, and stem cell behavior. In the skeletal system, certain capillaries support perivascular osteoprogenitor cells and thereby control bone formation. Blood vessels are also a critical component of niche microenvironments for hematopoietic stem cells. Here we discuss key pathways and factors controlling endothelial cell behavior in bone, the role of vessels in osteogenesis, and the nature of vascular stem cell niches in bone marrow.


Assuntos
Vasos Sanguíneos/metabolismo , Hematopoese , Osteogênese , Transdução de Sinais , Animais , Medula Óssea/irrigação sanguínea , Células Endoteliais/metabolismo , Humanos
2.
Immunity ; 45(4): 877-888, 2016 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-27760341

RESUMO

Lymph node (LN) expansion during an immune response relies on the transient remodeling of its vasculature. Although the mechanisms driving LN endothelial cell division are beginning to be understood, a comprehensive view of LN endothelial cell dynamics at the single-cell level is lacking. Here, we used multicolored fluorescent fate-mapping models to track the behavior of blood endothelial cells during LN expansion upon inflammation and subsequent return to homeostasis. We found that expansion of the LN vasculature relied on the sequential assembly of endothelial cell proliferative units. This segmented growth was sustained by the clonal proliferation of high endothelial venule (HEV) cells, which act as local progenitors to create capillaries and HEV neo-vessels at the periphery of the LN. Return to homeostasis was accompanied by the stochastic death of pre-existing and neo-synthesized LN endothelial cells. Thus, our fate-mapping studies unravel-at a single-cell level-the complex dynamics of vascular-tree remodeling during LN expansion and contraction.


Assuntos
Proliferação de Células/fisiologia , Células Endoteliais/imunologia , Células Endoteliais/fisiologia , Linfonodos/imunologia , Linfonodos/fisiologia , Animais , Capilares/imunologia , Capilares/fisiologia , Células Cultivadas , Homeostase/imunologia , Homeostase/fisiologia , Inflamação/imunologia , Inflamação/patologia , Camundongos
3.
Cell ; 143(1): 145-55, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20869108

RESUMO

The peripheral nervous system has astonishing regenerative capabilities in that cut nerves are able to reconnect and re-establish their function. Schwann cells are important players in this process, during which they dedifferentiate to a progenitor/stem cell and promote axonal regrowth. Here, we report that fibroblasts also play a key role. Upon nerve cut, ephrin-B/EphB2 signaling between fibroblasts and Schwann cells results in cell sorting, followed by directional collective cell migration of Schwann cells out of the nerve stumps to guide regrowing axons across the wound. Mechanistically, we find that cell-sorting downstream of EphB2 is mediated by the stemness factor Sox2 through N-cadherin relocalization to Schwann cell-cell contacts. In vivo, loss of EphB2 signaling impaired organized migration of Schwann cells, resulting in misdirected axonal regrowth. Our results identify a link between Ephs and Sox proteins, providing a mechanism by which progenitor cells can translate environmental cues to orchestrate the formation of new tissue.


Assuntos
Regeneração Nervosa , Nervos Periféricos/fisiologia , Receptor EphB2/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Células de Schwann/fisiologia , Animais , Axônios/metabolismo , Caderinas/metabolismo , Movimento Celular , Matriz Extracelular/metabolismo , Fibroblastos/fisiologia , Ratos , Células de Schwann/citologia , Transdução de Sinais
5.
Nature ; 569(7755): 222-228, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30971824

RESUMO

The bone marrow microenvironment has a key role in regulating haematopoiesis, but its molecular complexity and response to stress are incompletely understood. Here we map the transcriptional landscape of mouse bone marrow vascular, perivascular and osteoblast cell populations at single-cell resolution, both at homeostasis and under conditions of stress-induced haematopoiesis. This analysis revealed previously unappreciated levels of cellular heterogeneity within the bone marrow niche and resolved cellular sources of pro-haematopoietic growth factors, chemokines and membrane-bound ligands. Our studies demonstrate a considerable transcriptional remodelling of niche elements under stress conditions, including an adipocytic skewing of perivascular cells. Among the stress-induced changes, we observed that vascular Notch delta-like ligands (encoded by Dll1 and Dll4) were downregulated. In the absence of vascular Dll4, haematopoietic stem cells prematurely induced a myeloid transcriptional program. These findings refine our understanding of the cellular architecture of the bone marrow niche, reveal a dynamic and heterogeneous molecular landscape that is highly sensitive to stress and illustrate the utility of single-cell transcriptomic data in evaluating the regulation of haematopoiesis by discrete niche populations.


Assuntos
Medula Óssea/irrigação sanguínea , Microambiente Celular , Hematopoese , Células-Tronco Hematopoéticas , Análise de Célula Única , Nicho de Células-Tronco , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Diferenciação Celular , Linhagem da Célula , Endotélio Vascular/citologia , Feminino , Regulação da Expressão Gênica , Hematopoese/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Masculino , Camundongos , Células Mieloides/citologia , Células Mieloides/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , RNA-Seq , Receptores Notch/metabolismo , Nicho de Células-Tronco/genética , Estresse Fisiológico/genética , Transcriptoma/genética
6.
Circ Res ; 131(4): 308-327, 2022 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-35862101

RESUMO

BACKGROUND: Pericytes and vascular smooth muscle cells, collectively known as mural cells, are recruited through PDGFB (platelet-derived growth factor B)-PDGFRB (platelet-derived growth factor receptor beta) signaling. MCs are essential for vascular integrity, and their loss has been associated with numerous diseases. Most of this knowledge is based on studies in which MCs are insufficiently recruited or fully absent upon inducible ablation. In contrast, little is known about the physiological consequences that result from impairment of specific MC functions. Here, we characterize the role of the transcription factor SRF (serum response factor) in MCs and study its function in developmental and pathological contexts. METHODS: We generated a mouse model of MC-specific inducible Srf gene deletion and studied its consequences during retinal angiogenesis using RNA-sequencing, immunohistology, in vivo live imaging, and in vitro techniques. RESULTS: By postnatal day 6, pericytes lacking SRF were morphologically abnormal and failed to properly comigrate with angiogenic sprouts. As a consequence, pericyte-deficient vessels at the retinal sprouting front became dilated and leaky. By postnatal day 12, also the vascular smooth muscle cells had lost SRF, which coincided with the formation of pathological arteriovenous shunts. Mechanistically, we show that PDGFB-dependent SRF activation is mediated via MRTF (myocardin-related transcription factor) cofactors. We further show that MRTF-SRF signaling promotes pathological pericyte activation during ischemic retinopathy. RNA-sequencing, immunohistology, in vivo live imaging, and in vitro experiments demonstrated that SRF regulates expression of contractile SMC proteins essential to maintain the vascular tone. CONCLUSIONS: SRF is crucial for distinct functions in pericytes and vascular smooth muscle cells. SRF directs pericyte migration downstream of PDGFRB signaling and mediates pathological pericyte activation during ischemic retinopathy. In vascular smooth muscle cells, SRF is essential for expression of the contractile machinery, and its deletion triggers formation of arteriovenous shunts. These essential roles in physiological and pathological contexts provide a rationale for novel therapeutic approaches through targeting SRF activity in MCs.


Assuntos
Pericitos , Doenças Retinianas , Animais , Camundongos , Pericitos/metabolismo , Proteínas Proto-Oncogênicas c-sis/metabolismo , RNA/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Doenças Retinianas/metabolismo , Fator de Resposta Sérica/genética , Fator de Resposta Sérica/metabolismo
7.
Brain ; 146(9): 3634-3647, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36995941

RESUMO

Cerebral cavernous malformations (CCMs) and spinal cord cavernous malformations (SCCMs) are common vascular abnormalities of the CNS that can lead to seizure, haemorrhage and other neurological deficits. Approximately 85% of patients present with sporadic (versus congenital) CCMs. Somatic mutations in MAP3K3 and PIK3CA were recently reported in patients with sporadic CCM, yet it remains unknown whether MAP3K3 mutation is sufficient to induce CCMs. Here we analysed whole-exome sequencing data for patients with CCM and found that ∼40% of them have a single, specific MAP3K3 mutation [c.1323C>G (p.Ile441Met)] but not any other known mutations in CCM-related genes. We developed a mouse model of CCM with MAP3K3I441M uniquely expressed in the endothelium of the CNS. We detected pathological phenotypes similar to those found in patients with MAP3K3I441M. The combination of in vivo imaging and genetic labelling revealed that CCMs were initiated with endothelial expansion followed by disruption of the blood-brain barrier. Experiments with our MAP3K3I441M mouse model demonstrated that CCM can be alleviated by treatment with rapamycin, the mTOR inhibitor. CCM pathogenesis has usually been attributed to acquisition of two or three distinct genetic mutations involving the genes CCM1/2/3 and/or PIK3CA. However, our results demonstrate that a single genetic hit is sufficient to cause CCMs.


Assuntos
Hemangioma Cavernoso do Sistema Nervoso Central , Proteínas Proto-Oncogênicas , Animais , Camundongos , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Mutação/genética , Fenótipo , Medula Espinal/patologia
8.
Cell ; 137(6): 1124-35, 2009 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-19524514

RESUMO

The Notch pathway is a highly conserved signaling system that controls a diversity of growth, differentiation, and patterning processes. In growing blood vessels, sprouting of endothelial tip cells is inhibited by Notch signaling, which is activated by binding of the Notch receptor to its ligand Delta-like 4 (Dll4). Here, we show that the Notch ligand Jagged1 is a potent proangiogenic regulator in mice that antagonizes Dll4-Notch signaling in cells expressing Fringe family glycosyltransferases. Upon glycosylation of Notch, Dll4-Notch signaling is enhanced, whereas Jagged1 has weak signaling capacity and competes with Dll4. Our findings establish that the equilibrium between two Notch ligands with distinct spatial expression patterns and opposing functional roles regulates angiogenesis, a mechanism that might also apply to other Notch-controlled biological processes.


Assuntos
Vasos Sanguíneos/embriologia , Proteínas de Ligação ao Cálcio/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Neovascularização Fisiológica , Proteínas Adaptadoras de Transdução de Sinal , Animais , Vasos Sanguíneos/citologia , Proteínas de Ligação ao Cálcio/genética , Embrião de Mamíferos/metabolismo , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Feminino , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteína Jagged-1 , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Mutação , Receptores Notch/metabolismo , Retina/embriologia , Proteínas Serrate-Jagged
9.
Nature ; 557(7705): 439-445, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29743679

RESUMO

In vertebrate hearts, the ventricular trabecular myocardium develops as a sponge-like network of cardiomyocytes that is critical for contraction and conduction, ventricular septation, papillary muscle formation and wall thickening through the process of compaction 1 . Defective trabeculation leads to embryonic lethality2-4 or non-compaction cardiomyopathy (NCC) 5 . There are divergent views on when and how trabeculation is initiated in different species. In zebrafish, trabecular cardiomyocytes extrude from compact myocardium 6 , whereas in chicks, chamber wall thickening occurs before overt trabeculation 7 . In mice, the onset of trabeculation has not been described, but is proposed to begin at embryonic day 9.0, when cardiomyocytes form radially oriented ribs 2 . Endocardium-myocardium communication is essential for trabeculation, and numerous signalling pathways have been identified, including Notch2,8 and Neuregulin (NRG) 4 . Late disruption of the Notch pathway causes NCC 5 . Whereas it has been shown that mutations in the extracellular matrix (ECM) genes Has2 and Vcan prevent the formation of trabeculae in mice9,10 and the matrix metalloprotease ADAMTS1 promotes trabecular termination 3 , the pathways involved in ECM dynamics and the molecular regulation of trabeculation during its early phases remain unexplored. Here we present a model of trabeculation in mice that integrates dynamic endocardial and myocardial cell behaviours and ECM remodelling, and reveal new epistatic relationships between the involved signalling pathways. NOTCH1 signalling promotes ECM degradation during the formation of endocardial projections that are critical for individualization of trabecular units, whereas NRG1 promotes myocardial ECM synthesis, which is necessary for trabecular rearrangement and growth. These systems interconnect through NRG1 control of Vegfa, but act antagonistically to establish trabecular architecture. These insights enabled the prediction of persistent ECM and cardiomyocyte growth in a mouse NCC model, providing new insights into the pathophysiology of congenital heart disease.


Assuntos
Coração/embriologia , Miocárdio/citologia , Miocárdio/metabolismo , Neuregulina-1/metabolismo , Organogênese , Receptor Notch1/metabolismo , Animais , Modelos Animais de Doenças , Endocárdio/citologia , Endocárdio/metabolismo , Matriz Extracelular/metabolismo , Cardiopatias/congênito , Cardiopatias/metabolismo , Camundongos , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Neuregulina-1/genética , Receptor Notch1/genética , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/metabolismo
10.
Proc Natl Acad Sci U S A ; 118(17)2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33875597

RESUMO

G protein-coupled receptor 182 (GPR182) has been shown to be expressed in endothelial cells; however, its ligand and physiological role has remained elusive. We found GPR182 to be expressed in microvascular and lymphatic endothelial cells of most organs and to bind with nanomolar affinity the chemokines CXCL10, CXCL12, and CXCL13. In contrast to conventional chemokine receptors, binding of chemokines to GPR182 did not induce typical downstream signaling processes, including Gq- and Gi-mediated signaling or ß-arrestin recruitment. GPR182 showed relatively high constitutive activity in regard to ß-arrestin recruitment and rapidly internalized in a ligand-independent manner. In constitutive GPR182-deficient mice, as well as after induced endothelium-specific loss of GPR182, we found significant increases in the plasma levels of CXCL10, CXCL12, and CXCL13. Global and induced endothelium-specific GPR182-deficient mice showed a significant decrease in hematopoietic stem cells in the bone marrow as well as increased colony-forming units of hematopoietic progenitors in the blood and the spleen. Our data show that GPR182 is a new atypical chemokine receptor for CXCL10, CXCL12, and CXCL13, which is involved in the regulation of hematopoietic stem cell homeostasis.


Assuntos
Receptores Acoplados a Proteínas G/metabolismo , Animais , Quimiocina CXCL10 , Quimiocina CXCL12 , Quimiocina CXCL13 , Quimiocinas/metabolismo , Células Endoteliais/metabolismo , Feminino , Células HEK293 , Células-Tronco Hematopoéticas/metabolismo , Homeostase , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Quimiocinas/metabolismo , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/fisiologia , beta-Arrestinas/metabolismo
11.
Blood ; 138(21): 2051-2065, 2021 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-34370827

RESUMO

Hematopoietic stem and progenitor cell (HSPC) function in bone marrow (BM) is controlled by stroma-derived signals, but the identity and interplay of these signals remain incompletely understood. Here, we show that sympathetic nerve-derived dopamine directly controls HSPC behavior through D2 subfamily dopamine receptors. Blockade of dopamine synthesis, as well as pharmacological or genetic inactivation of D2 subfamily dopamine receptors, leads to reduced HSPC frequency, inhibition of proliferation, and low BM transplantation efficiency. Conversely, treatment with a D2-type receptor agonist increases BM regeneration and transplantation efficiency. Mechanistically, dopamine controls expression of the lymphocyte-specific protein tyrosine kinase (Lck), which, in turn, regulates MAPK-mediated signaling triggered by stem cell factor in HSPCs. Our work reveals critical functional roles of dopamine in HSPCs, which may open up new therapeutic options for improved BM transplantation and other conditions requiring the rapid expansion of HSPCs.


Assuntos
Dopamina/metabolismo , Células-Tronco Hematopoéticas/citologia , Receptores de Dopamina D2/metabolismo , Transdução de Sinais , Animais , Transplante de Medula Óssea , Proliferação de Células , Células Cultivadas , Células-Tronco Hematopoéticas/metabolismo , Camundongos
12.
Respir Res ; 24(1): 167, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37349733

RESUMO

BACKGROUND: The origin of αSMA-positive myofibroblasts, key players within organ fibrosis, is still not fully elucidated. Pericytes have been discussed as myofibroblast progenitors in several organs including the lung. METHODS: Using tamoxifen-inducible PDGFRß-tdTomato mice (PDGFRß-CreERT2; R26tdTomato) lineage of lung pericytes was traced. To induce lung fibrosis, a single orotracheal dose of bleomycin was given. Lung tissue was investigated by immunofluorescence analyses, hydroxyproline collagen assay and RT-qPCR. RESULTS: Lineage tracing combined with immunofluorescence for nitric oxide-sensitive guanylyl cyclase (NO-GC) as marker for PDGFRß-positive pericytes allows differentiating two types of αSMA-expressing myofibroblasts in murine pulmonary fibrosis: (1) interstitial myofibroblasts that localize in the alveolar wall, derive from PDGFRß+ pericytes, express NO-GC and produce collagen 1. (2) intra-alveolar myofibroblasts which do not derive from pericytes (but express PDGFRß de novo after injury), are negative for NO-GC, have a large multipolar shape and appear to spread over several alveoli within the injured areas. Moreover, NO-GC expression is reduced during fibrosis, i.e., after pericyte-to-myofibroblast transition. CONCLUSION: In summary, αSMA/PDGFRß-positive myofibroblasts should not be addressed as a homogeneous target cell type within pulmonary fibrosis.


Assuntos
Fibrose Pulmonar , Camundongos , Animais , Fibrose Pulmonar/metabolismo , Pericitos/metabolismo , Miofibroblastos/metabolismo , Guanilato Ciclase/metabolismo , Fibrose , Colágeno/metabolismo
13.
FASEB J ; 36(10): e22538, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36065631

RESUMO

Antipsychotic agents are clinically utilized to treat schizophrenia and other mental disorders. These drugs induce neurological and metabolic side effects, but their influence on blood vessels remains largely unknown. Here, we show that haloperidol, one of the most frequently prescribed antipsychotic agents, induces vascular defects in bone marrow. Acute haloperidol treatment results in vascular dilation that is specific to hematopoietic organs. This vessel dilation is associated with disruption of hematopoiesis and hematopoietic stem/progenitor cells (HSPCs), both of which are reversible after haloperidol withdrawal. Mechanistically, haloperidol treatment blocked the secretion of vascular endothelial growth factor A (VEGF-A) from HSPCs. Genetic blockade of VEGF-A secretion from hematopoietic cells or inhibition of VEGFR2 in endothelial cells result in similar vessel dilation in bone marrow during regeneration after irradiation and transplantation. Conversely, VEGF-A gain of function rescues the bone marrow vascular defects induced by haloperidol treatment and irradiation. Our work reveals an unknown effect of antipsychotic agents on the vasculature and hematopoiesis with potential implications for drug application in clinic.


Assuntos
Antipsicóticos , Fator A de Crescimento do Endotélio Vascular , Antipsicóticos/farmacologia , Células da Medula Óssea/metabolismo , Células Endoteliais/metabolismo , Haloperidol/metabolismo , Haloperidol/farmacologia , Hematopoese/fisiologia , Humanos , Fator A de Crescimento do Endotélio Vascular/metabolismo
14.
Nature ; 532(7599): 380-4, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-27074508

RESUMO

Blood vessels define local microenvironments in the skeletal system, play crucial roles in osteogenesis and provide niches for haematopoietic stem cells. The properties of niche-forming vessels and their changes in the ageing organism remain incompletely understood. Here we show that Notch signalling in endothelial cells leads to the expansion of haematopoietic stem cell niches in bone, which involves increases in CD31-positive capillaries and platelet-derived growth factor receptor-ß (PDGFRß)-positive perivascular cells, arteriole formation and elevated levels of cellular stem cell factor. Although endothelial hypoxia-inducible factor signalling promotes some of these changes, it fails to enhance vascular niche function because of a lack of arterialization and expansion of PDGFRß-positive cells. In ageing mice, niche-forming vessels in the skeletal system are strongly reduced but can be restored by activation of endothelial Notch signalling. These findings indicate that vascular niches for haematopoietic stem cells are part of complex, age-dependent microenvironments involving multiple cell populations and vessel subtypes.


Assuntos
Envelhecimento/fisiologia , Arteríolas/fisiologia , Osso e Ossos/irrigação sanguínea , Capilares/fisiologia , Células-Tronco Hematopoéticas/citologia , Nicho de Células-Tronco , Animais , Arteríolas/citologia , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Capilares/citologia , Contagem de Células , Células Endoteliais/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Camundongos , Osteogênese , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais , Fator de Células-Tronco/metabolismo
15.
Nature ; 532(7599): 323-8, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-27074509

RESUMO

Bone marrow endothelial cells (BMECs) form a network of blood vessels that regulate both leukocyte trafficking and haematopoietic stem and progenitor cell (HSPC) maintenance. However, it is not clear how BMECs balance these dual roles, and whether these events occur at the same vascular site. We found that mammalian bone marrow stem cell maintenance and leukocyte trafficking are regulated by distinct blood vessel types with different permeability properties. Less permeable arterial blood vessels maintain haematopoietic stem cells in a low reactive oxygen species (ROS) state, whereas the more permeable sinusoids promote HSPC activation and are the exclusive site for immature and mature leukocyte trafficking to and from the bone marrow. A functional consequence of high permeability of blood vessels is that exposure to blood plasma increases bone marrow HSPC ROS levels, augmenting their migration and differentiation, while compromising their long-term repopulation and survival. These findings may have relevance for clinical haematopoietic stem cell transplantation and mobilization protocols.


Assuntos
Vasos Sanguíneos/citologia , Vasos Sanguíneos/fisiologia , Medula Óssea/irrigação sanguínea , Hematopoese , Animais , Antígenos Ly/metabolismo , Artérias/citologia , Artérias/fisiologia , Células da Medula Óssea/citologia , Diferenciação Celular , Movimento Celular , Autorrenovação Celular , Sobrevivência Celular , Quimiocina CXCL12/metabolismo , Células Endoteliais/fisiologia , Feminino , Mobilização de Células-Tronco Hematopoéticas , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Leucócitos/citologia , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Nestina/metabolismo , Pericitos/fisiologia , Permeabilidade , Plasma/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores CXCR4/metabolismo
16.
Int J Mol Sci ; 23(21)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36361868

RESUMO

Pericytes at the blood-brain barrier (BBB) are located between the tight endothelial cell layer of the blood vessels and astrocytic endfeet. They contribute to central nervous system (CNS) homeostasis by regulating BBB development and maintenance. Loss of pericytes results in increased numbers of infiltrating immune cells in the CNS in experimental autoimmune encephalomyelitis (EAE), the mouse model for multiple sclerosis (MS). However, little is known about their competence to modulate immune cell activation or function in CNS autoimmunity. To evaluate the capacity of pericytes to directly interact with T cells in an antigen-specific fashion and potentially (re)shape their function, we depleted major histocompatibility complex (MHC) class II from pericytes in a cell type-specific fashion and performed T cell-pericyte cocultures and EAE experiments. We found that pericytes present antigen in vitro to induce T cell activation and proliferation. In an adoptive transfer EAE experiment, pericyte-specific MHC II KO resulted in locally enhanced T cell infiltration in the CNS; even though, overall disease course of mice was not affected. Thus, pericytes may serve as non-professional antigen-presenting cells affecting states of T cell activation, thereby locally shaping lesion formation in CNS inflammation but without modulating disease severity.


Assuntos
Encefalomielite Autoimune Experimental , Camundongos , Animais , Encefalomielite Autoimune Experimental/patologia , Pericitos/patologia , Linfócitos T , Sistema Nervoso Central/patologia , Barreira Hematoencefálica/patologia , Antígenos , Antígenos de Histocompatibilidade Classe II , Camundongos Endogâmicos C57BL
17.
Circulation ; 142(7): 688-704, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32466671

RESUMO

BACKGROUND: Pericytes regulate vessel stabilization and function, and their loss is associated with diseases such as diabetic retinopathy or cancer. Despite their physiological importance, pericyte function and molecular regulation during angiogenesis remain poorly understood. METHODS: To decipher the transcriptomic programs of pericytes during angiogenesis, we crossed Pdgfrb(BAC)-CreERT2 mice into RiboTagflox/flox mice. Pericyte morphological changes were assessed in mural cell-specific R26-mTmG reporter mice, in which low doses of tamoxifen allowed labeling of single-cell pericytes at high resolution. To study the role of phosphoinositide 3-kinase (PI3K) signaling in pericyte biology during angiogenesis, we used genetic mouse models that allow selective inactivation of PI3Kα and PI3Kß isoforms and their negative regulator phosphate and tensin homolog deleted on chromosome 10 (PTEN) in mural cells. RESULTS: At the onset of angiogenesis, pericytes exhibit molecular traits of cell proliferation and activated PI3K signaling, whereas during vascular remodeling, pericytes upregulate genes involved in mature pericyte cell function, together with a remarkable decrease in PI3K signaling. Immature pericytes showed stellate shape and high proliferation, and mature pericytes were quiescent and elongated. Unexpectedly, we demonstrate that PI3Kß, but not PI3Kα, regulates pericyte proliferation and maturation during vessel formation. Genetic PI3Kß inactivation in pericytes triggered early pericyte maturation. Conversely, unleashing PI3K signaling by means of PTEN deletion delayed pericyte maturation. Pericyte maturation was necessary to undergo vessel remodeling during angiogenesis. CONCLUSIONS: Our results identify new molecular and morphological traits associated with pericyte maturation and uncover PI3Kß activity as a checkpoint to ensure appropriate vessel formation. In turn, our results may open new therapeutic opportunities to regulate angiogenesis in pathological processes through the manipulation of pericyte PI3Kß activity.


Assuntos
Neovascularização Fisiológica , Pericitos/enzimologia , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais , Remodelação Vascular , Animais , Camundongos , Camundongos Transgênicos , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/genética
18.
EMBO J ; 36(16): 2373-2389, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28694244

RESUMO

Tumor progression alters the composition and physical properties of the extracellular matrix. Particularly, increased matrix stiffness has profound effects on tumor growth and metastasis. While endothelial cells are key players in cancer progression, the influence of tumor stiffness on the endothelium and the impact on metastasis is unknown. Through quantitative mass spectrometry, we find that the matricellular protein CCN1/CYR61 is highly regulated by stiffness in endothelial cells. We show that stiffness-induced CCN1 activates ß-catenin nuclear translocation and signaling and that this contributes to upregulate N-cadherin levels on the surface of the endothelium, in vitro This facilitates N-cadherin-dependent cancer cell-endothelium interaction. Using intravital imaging, we show that knockout of Ccn1 in endothelial cells inhibits melanoma cancer cell binding to the blood vessels, a critical step in cancer cell transit through the vasculature to metastasize. Targeting stiffness-induced changes in the vasculature, such as CCN1, is therefore a potential yet unappreciated mechanism to impair metastasis.


Assuntos
Comunicação Celular , Células Endoteliais/fisiologia , Melanócitos/fisiologia , Caderinas/análise , Linhagem Celular , Proteína Rica em Cisteína 61/análise , Regulação da Expressão Gênica , Humanos , Espectrometria de Massas , beta Catenina/análise
19.
Circ Res ; 124(4): 511-525, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30591003

RESUMO

RATIONALE: The microvasculature of the central nervous system includes the blood-brain barrier (BBB), which regulates the permeability to nutrients and restricts the passage of toxic agents and inflammatory cells. Canonical Wnt/ß-catenin signaling is responsible for the early phases of brain vascularization and BBB differentiation. However, this signal declines after birth, and other signaling pathways able to maintain barrier integrity at postnatal stage are still unknown. OBJECTIVE: Sox17 (SRY [sex-determining region Y]-box 17) constitutes a major downstream target of Wnt/ß-catenin in endothelial cells and regulates arterial differentiation. In the present article, we asked whether Sox17 may act downstream of Wnt/ß-catenin in inducing BBB differentiation and maintenance. METHODS AND RESULTS: Using reporter mice and nuclear staining of Sox17 and ß-catenin, we report that although ß-catenin signaling declines after birth, Sox17 activation increases and remains high in the adult. Endothelial-specific inactivation of Sox17 leads to increase of permeability of the brain microcirculation. The severity of this effect depends on the degree of BBB maturation: it is strong in the embryo and progressively declines after birth. In search of Sox17 mechanism of action, RNA sequencing analysis of gene expression of brain endothelial cells has identified members of the Wnt/ß-catenin signaling pathway as downstream targets of Sox17. Consistently, we found that Sox17 is a positive inducer of Wnt/ß-catenin signaling, and it acts in concert with this pathway to induce and maintain BBB properties. In vivo, inhibition of the ß-catenin destruction complex or expression of a degradation-resistant ß-catenin mutant, prevent the increase in permeability and retina vascular malformations observed in the absence of Sox17. CONCLUSIONS: Our data highlight a novel role for Sox17 in the induction and maintenance of the BBB, and they underline the strict reciprocal tuning of this transcription factor and Wnt/ß-catenin pathway. Modulation of Sox17 activity may be relevant to control BBB permeability in pathological conditions.


Assuntos
Barreira Hematoencefálica/metabolismo , Permeabilidade Capilar , Proteínas HMGB/metabolismo , Fatores de Transcrição SOXF/metabolismo , Via de Sinalização Wnt , Animais , Proteínas HMGB/genética , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Transcrição SOXF/genética
20.
Arterioscler Thromb Vasc Biol ; 40(4): 958-972, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32078339

RESUMO

OBJECTIVE: Angiocrine factors, mediating the endothelial-mural cell interaction in vascular wall construction as well as maintenance, are incompletely characterized. This study aims to investigate the role of endothelial cell-derived FSTL1 (follistatin-like protein 1) in vascular homeostasis. Approach and Results: Using conditional knockout mouse models, we show that loss of FSTL1 in endothelial cells (Fstl1ECKO) led to an increase of pulmonary vascular resistance, resulting in the heart regurgitation especially with tricuspid valves. However, this abnormality was not detected in mutant mice with Fstl1 knockout in smooth muscle cells or hematopoietic cells. We further showed that there was excessive αSMA (α-smooth muscle actin) associated with atrial endocardia, heart valves, veins, and microvessels after the endothelial FSTL1 deletion. There was also an increase in collagen deposition, as demonstrated in livers of Fstl1ECKO mutants. The SMAD3 (mothers against decapentaplegic homolog 3) phosphorylation (pSMAD3) was significantly enhanced, and pSMAD3 staining was colocalized with αSMA in vein walls, suggesting the activation of TGFß (transforming growth factor ß) signaling in vascular mural cells of Fstl1ECKO mice. Consistently, treatment with a TGFß pathway inhibitor reduced the abnormal association of αSMA with the atria and blood vessels in Fstl1ECKO mutant mice. CONCLUSIONS: The findings imply that endothelial FSTL1 is critical for the homeostasis of vascular walls, and its insufficiency may favor cardiovascular fibrosis leading to heart failure.


Assuntos
Endotélio Vascular/fisiopatologia , Fibrose/fisiopatologia , Proteínas Relacionadas à Folistatina/fisiologia , Proteína Smad3/fisiologia , Actinas/metabolismo , Animais , Modelos Animais de Doenças , Células Endoteliais/fisiologia , Proteínas Relacionadas à Folistatina/metabolismo , Homeostase , Humanos , Camundongos Knockout , Fosforilação , Proteína Smad3/metabolismo , Fator de Crescimento Transformador beta/fisiologia , Insuficiência da Valva Tricúspide/fisiopatologia , Resistência Vascular
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