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1.
Cell ; 152(5): 1065-76, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23452854

RESUMO

Medulloblastoma is the most common pediatric malignant brain tumor. Although current therapies improve survival, these regimens are highly toxic and are associated with significant morbidity. Here, we report that placental growth factor (PlGF) is expressed in the majority of medulloblastomas, independent of their subtype. Moreover, high expression of PlGF receptor neuropilin 1 (Nrp1) correlates with poor overall survival in patients. We demonstrate that PlGF and Nrp1 are required for the growth and spread of medulloblastoma: PlGF/Nrp1 blockade results in direct antitumor effects in vivo, resulting in medulloblastoma regression, decreased metastasis, and increased mouse survival. We reveal that PlGF is produced in the cerebellar stroma via tumor-derived Sonic hedgehog (Shh) and show that PlGF acts through Nrp1-and not vascular endothelial growth factor receptor 1-to promote tumor cell survival. This critical tumor-stroma interaction-mediated by Shh, PlGF, and Nrp1 across medulloblastoma subtypes-supports the development of therapies targeting PlGF/Nrp1 pathway.


Assuntos
Neoplasias Cerebelares/patologia , Cerebelo/metabolismo , Meduloblastoma/patologia , Neuropilina-1/metabolismo , Proteínas da Gravidez/metabolismo , Transdução de Sinais , Animais , Células Cultivadas , Neoplasias Cerebelares/metabolismo , Humanos , Meduloblastoma/metabolismo , Camundongos , Camundongos Knockout , Transplante de Neoplasias , Comunicação Parácrina , Fator de Crescimento Placentário , Transplante Heterólogo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo
2.
Mol Cell Neurosci ; 57: 63-72, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24141049

RESUMO

During the first postnatal days in the mouse, granule cells (GCs) undergo massive proliferation, which then gradually decreases. Matrix metalloproteinase-2 (MMP-2), a Zn(2+)-dependent proteolytic enzyme, is involved in a wide variety of pathological and physiological pathways. Evidence for a role of this proteinase in cell proliferation is emerging, reporting its involvement in pathological proliferation, as well as during neurogenesis and developmental proliferation of non-CNS tissues. In this study, MMP-2 protein expression was observed within the early postnatal cerebellar cortex, predominantly in Purkinje cells and within the GC proliferative zone, i.e. the superficial external granular layer (EGL). Consistently, the spatiotemporal MMP-2 mRNA and protein profiles highly correlated with the peak of GC precursor (GCP) proliferation and detailed morphometric analyses of MMP-2 deficient cerebella revealed a thinner EGL due to a decreased GCP proliferation. BrdU cumulative experiments, performed to measure the length of different cell cycle phases, further disclosed a transiently prolonged S-phase in MMP-2 deficient GCPs during early cerebellar development. In consequence, MMP-2 deficient animals displayed a transient delay in GC migration towards the IGL. In conclusion, our findings provide important evidence for a role for MMP-2 in neuronal proliferation and cell cycle kinetics in the developing CNS.


Assuntos
Proliferação de Células , Cerebelo/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Células de Purkinje/metabolismo , Animais , Movimento Celular , Cerebelo/citologia , Cerebelo/enzimologia , Cerebelo/crescimento & desenvolvimento , Metaloproteinase 2 da Matriz/genética , Camundongos , Camundongos Endogâmicos C57BL , Células de Purkinje/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
3.
Proc Natl Acad Sci U S A ; 108(33): 13782-7, 2011 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-21804034

RESUMO

NMDA type glutamate receptors (NMDARs) are best known for their role in synaptogenesis and synaptic plasticity. Much less is known about their developmental role before neurons form synapses. We report here that VEGF, which promotes migration of granule cells (GCs) during postnatal cerebellar development, enhances NMDAR-mediated currents and Ca(2+) influx in immature GCs before synapse formation. The VEGF receptor Flk1 forms a complex with the NMDAR subunits NR1 and NR2B. In response to VEGF, the number of Flk1/NR2B coclusters on the cell surface increases. Stimulation of Flk1 by VEGF activates Src-family kinases, which increases tyrosine phosphorylation of NR2B. Inhibition of Src-family kinases abolishes the VEGF-dependent NR2B phosphorylation and amplification of NMDAR-mediated currents and Ca(2+) influx in GCs. These findings identify VEGF as a modulator of NMDARs before synapse formation and highlight a link between an activity-independent neurovascular guidance cue (VEGF) and an activity-regulated neurotransmitter receptor (NMDAR).


Assuntos
Cerebelo/citologia , Neurônios/ultraestrutura , Receptores de N-Metil-D-Aspartato/fisiologia , Fator A de Crescimento do Endotélio Vascular/fisiologia , Quinases da Família src/metabolismo , Indutores da Angiogênese , Animais , Cálcio/metabolismo , Camundongos , Complexos Multiproteicos , Fosforilação , Receptores de Neurotransmissores , Sinapses , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
4.
Nat Chem Biol ; 7(10): 701-11, 2011 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-21873995

RESUMO

Oxygen (O(2)) is a prerequisite for cellular respiration in aerobic organisms but also elicits toxicity. To understand how animals cope with the ambivalent physiological nature of O(2), it is critical to elucidate the molecular mechanisms responsible for O(2) sensing. Here our systematic evaluation of transient receptor potential (TRP) cation channels using reactive disulfides with different redox potentials reveals the capability of TRPA1 to sense O(2). O(2) sensing is based upon disparate processes: whereas prolyl hydroxylases (PHDs) exert O(2)-dependent inhibition on TRPA1 activity in normoxia, direct O(2) action overrides the inhibition via the prominent sensitivity of TRPA1 to cysteine-mediated oxidation in hyperoxia. Unexpectedly, TRPA1 is activated through relief from the same PHD-mediated inhibition in hypoxia. In mice, disruption of the Trpa1 gene abolishes hyperoxia- and hypoxia-induced cationic currents in vagal and sensory neurons and thereby impedes enhancement of in vivo vagal discharges induced by hyperoxia and hypoxia. The results suggest a new O(2)-sensing mechanism mediated by TRPA1.


Assuntos
Oxigênio/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Animais , Células Cultivadas , Humanos , Hipóxia , Camundongos , Camundongos Knockout , Estrutura Molecular , Oxigênio/química , Pró-Colágeno-Prolina Dioxigenase/química , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Estereoisomerismo , Canal de Cátion TRPA1 , Canais de Potencial de Receptor Transitório/química , Canais de Potencial de Receptor Transitório/deficiência
5.
J Neurosci ; 30(45): 15052-66, 2010 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-21068311

RESUMO

Vascular endothelial growth factor (VEGF) regulates angiogenesis, but also has important, yet poorly characterized roles in neuronal wiring. Using several genetic and in vitro approaches, we discovered a novel role for VEGF in the control of cerebellar granule cell (GC) migration from the external granule cell layer (EGL) toward the Purkinje cell layer (PCL). GCs express the VEGF receptor Flk1, and are chemoattracted by VEGF, whose levels are higher in the PCL than EGL. Lowering VEGF levels in mice in vivo or ectopic VEGF expression in the EGL ex vivo perturbs GC migration. Using GC-specific Flk1 knock-out mice, we provide for the first time in vivo evidence for a direct chemoattractive effect of VEGF on neurons via Flk1 signaling. Finally, using knock-in mice expressing single VEGF isoforms, we show that pericellular deposition of matrix-bound VEGF isoforms around PC dendrites is necessary for proper GC migration in vivo. These findings identify a previously unknown role for VEGF in neuronal migration.


Assuntos
Movimento Celular/fisiologia , Cerebelo/fisiologia , Neurônios/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Apoptose/fisiologia , Western Blotting , Células Cultivadas , Cerebelo/citologia , Ensaio de Imunoadsorção Enzimática , Cones de Crescimento/metabolismo , Células HEK293 , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Neurônios/citologia , Isoformas de Proteínas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética
7.
Cell Rep ; 14(11): 2653-67, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-26972007

RESUMO

Neuronal function is highly sensitive to changes in oxygen levels, but how hypoxia affects dendritic spine formation and synaptogenesis is unknown. Here we report that hypoxia, chemical inhibition of the oxygen-sensing prolyl hydroxylase domain proteins (PHDs), and silencing of Phd2 induce immature filopodium-like dendritic protrusions, promote spine regression, reduce synaptic density, and decrease the frequency of spontaneous action potentials independently of HIF signaling. We identified the actin cross-linker filamin A (FLNA) as a target of PHD2 mediating these effects. In normoxia, PHD2 hydroxylates the proline residues P2309 and P2316 in FLNA, leading to von Hippel-Lindau (VHL)-mediated ubiquitination and proteasomal degradation. In hypoxia, PHD2 inactivation rapidly upregulates FLNA protein levels because of blockage of its proteasomal degradation. FLNA upregulation induces more immature spines, whereas Flna silencing rescues the immature spine phenotype induced by PHD2 inhibition.


Assuntos
Espinhas Dendríticas/metabolismo , Filaminas/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Sinapses/metabolismo , Aminoácidos Dicarboxílicos/farmacologia , Animais , Hipóxia Celular , Linhagem Celular Tumoral , Células Cultivadas , Filaminas/antagonistas & inibidores , Filaminas/genética , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/antagonistas & inibidores , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética , Camundongos , Camundongos Knockout , Oxigênio/metabolismo , Ratos , Ratos Wistar , Tubulina (Proteína)/metabolismo , Regulação para Cima/efeitos dos fármacos , Proteína Supressora de Tumor Von Hippel-Lindau/antagonistas & inibidores , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo
8.
Neuron ; 70(5): 966-78, 2011 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-21658588

RESUMO

Growing axons are guided to their targets by attractive and repulsive cues. In the developing spinal cord, Netrin-1 and Shh guide commissural axons toward the midline. However, the combined inhibition of their activity in commissural axon turning assays does not completely abrogate turning toward floor plate tissue, suggesting that additional guidance cues are present. Here we show that the prototypic angiogenic factor VEGF is secreted by the floor plate and is a chemoattractant for commissural axons in vitro and in vivo. Inactivation of Vegf in the floor plate or of its receptor Flk1 in commissural neurons causes axon guidance defects, whereas Flk1 blockade inhibits turning of axons to VEGF in vitro. Similar to Shh and Netrin-1, VEGF-mediated commissural axon guidance requires the activity of Src family kinases. Our results identify VEGF and Flk1 as a novel ligand/receptor pair controlling commissural axon guidance.


Assuntos
Axônios/fisiologia , Quimiotaxia/fisiologia , Quiasma Óptico/citologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Células Cultivadas , Quimiotaxia/genética , Embrião de Mamíferos , Ensaio de Imunoadsorção Enzimática/métodos , Glicosídeo Hidrolases/metabolismo , Cones de Crescimento/metabolismo , Proteínas Hedgehog/metabolismo , Técnicas In Vitro , Camundongos , Camundongos Transgênicos , Fatores de Crescimento Neural/metabolismo , Netrina-1 , Neurônios/citologia , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Proteínas Supressoras de Tumor/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Proteína Wnt1/genética
9.
Cancer Cell ; 19(1): 31-44, 2011 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-21215706

RESUMO

Polarization of tumor-associated macrophages (TAMs) to a proangiogenic/immune-suppressive (M2-like) phenotype and abnormal, hypoperfused vessels are hallmarks of malignancy, but their molecular basis and interrelationship remains enigmatic. We report that the host-produced histidine-rich glycoprotein (HRG) inhibits tumor growth and metastasis, while improving chemotherapy. By skewing TAM polarization away from the M2- to a tumor-inhibiting M1-like phenotype, HRG promotes antitumor immune responses and vessel normalization, effects known to decrease tumor growth and metastasis and to enhance chemotherapy. Skewing of TAM polarization by HRG relies substantially on downregulation of placental growth factor (PlGF). Besides unveiling an important role for TAM polarization in tumor vessel abnormalization, and its regulation by HRG/PlGF, these findings offer therapeutic opportunities for anticancer and antiangiogenic treatment.


Assuntos
Regulação para Baixo/genética , Macrófagos/imunologia , Neoplasias/imunologia , Neoplasias/patologia , Neovascularização Patológica/imunologia , Proteínas da Gravidez/metabolismo , Proteínas/metabolismo , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fatores Quimiotáticos/metabolismo , Ácido Clodrônico/farmacologia , Meios de Cultivo Condicionados/farmacologia , Citocinas/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Células Dendríticas/patologia , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/genética , Humanos , Hipóxia/genética , Hipóxia/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/secundário , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/patologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microvasos/efeitos dos fármacos , Microvasos/patologia , Microvasos/ultraestrutura , Metástase Neoplásica/genética , Metástase Neoplásica/imunologia , Metástase Neoplásica/patologia , Neoplasias/irrigação sanguínea , Neoplasias/genética , Neoplasias/metabolismo , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Fator de Crescimento Placentário , Proteínas da Gravidez/genética , Proteínas da Gravidez/imunologia , Proteínas/genética , Proteínas/farmacologia
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