RESUMO
Activation of endothelial YAP/TAZ signaling is crucial for physiological and pathological angiogenesis. The mechanisms of endothelial YAP/TAZ regulation are, however, incompletely understood. Here we report that the protocadherin FAT1 acts as a critical upstream regulator of endothelial YAP/TAZ which limits the activity of these transcriptional cofactors during developmental and tumor angiogenesis by promoting their degradation. We show that loss of endothelial FAT1 results in increased endothelial cell proliferation in vitro and in various angiogenesis models in vivo. This effect is due to perturbed YAP/TAZ protein degradation, leading to increased YAP/TAZ protein levels and expression of canonical YAP/TAZ target genes. We identify the E3 ubiquitin ligase Mind Bomb-2 (MIB2) as a FAT1-interacting protein mediating FAT1-induced YAP/TAZ ubiquitination and degradation. Loss of MIB2 expression in endothelial cells in vitro and in vivo recapitulates the effects of FAT1 depletion and causes decreased YAP/TAZ degradation and increased YAP/TAZ signaling. Our data identify a pivotal mechanism of YAP/TAZ regulation involving FAT1 and its associated E3 ligase MIB2, which is essential for YAP/TAZ-dependent angiogenesis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Transativadores , Humanos , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteólise , Transativadores/metabolismo , Células Endoteliais/metabolismo , Proteínas de Sinalização YAP , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Neovascularização Patológica/metabolismo , Fosfoproteínas/metabolismo , Caderinas/metabolismoRESUMO
G-protein-coupled receptors (GPCRs), especially chemokine receptors, play a central role in the regulation of T cell migration. Various GPCRs are upregulated in activated CD4 T cells, including P2Y10, a putative lysophospholipid receptor that is officially still considered an orphan GPCR, i.e., a receptor with unknown endogenous ligand. Here we show that in mice lacking P2Y10 in the CD4 T cell compartment, the severity of experimental autoimmune encephalomyelitis and cutaneous contact hypersensitivity is reduced. P2Y10-deficient CD4 T cells show normal activation, proliferation and differentiation, but reduced chemokine-induced migration, polarization, and RhoA activation upon in vitro stimulation. Mechanistically, CD4 T cells release the putative P2Y10 ligands lysophosphatidylserine and ATP upon chemokine exposure, and these mediators induce P2Y10-dependent RhoA activation in an autocrine/paracrine fashion. ATP degradation impairs RhoA activation and migration in control CD4 T cells, but not in P2Y10-deficient CD4 T cells. Importantly, the P2Y10 pathway appears to be conserved in human T cells. Taken together, P2Y10 mediates RhoA activation in CD4 T cells in response to auto-/paracrine-acting mediators such as LysoPS and ATP, thereby facilitating chemokine-induced migration and, consecutively, T cell-mediated diseases.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Encefalomielite Autoimune Experimental/imunologia , Esclerose Múltipla/imunologia , Receptores Purinérgicos P2Y/metabolismo , Receptores Purinérgicos P2/metabolismo , Trifosfato de Adenosina/metabolismo , Adulto , Idoso , Animais , Comunicação Autócrina/imunologia , Linfócitos T CD4-Positivos/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Quimiocinas/metabolismo , Quimiotaxia de Leucócito/imunologia , Encefalomielite Autoimune Experimental/sangue , Feminino , Técnicas de Silenciamento de Genes , Técnicas de Inativação de Genes , Humanos , Lisofosfolipídeos/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Comunicação Parácrina/imunologia , Cultura Primária de Células , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2Y/genética , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
White adipose tissue (WAT) expansion in obesity occurs through enlargement of preexisting adipocytes (hypertrophy) and through formation of new adipocytes (adipogenesis). Adipogenesis results in WAT hyperplasia, smaller adipocytes and a metabolically more favourable form of obesity. How obesogenic WAT hyperplasia is induced remains, however, poorly understood. Here, we show that the mechanosensitive cationic channel Piezo1 mediates diet-induced adipogenesis. Mice lacking Piezo1 in mature adipocytes demonstrated defective differentiation of preadipocyte into mature adipocytes when fed a high fat diet (HFD) resulting in larger adipocytes, increased WAT inflammation and reduced insulin sensitivity. Opening of Piezo1 in mature adipocytes causes the release of the adipogenic fibroblast growth factor 1 (FGF1), which induces adipocyte precursor differentiation through activation of the FGF-receptor-1. These data identify a central feed-back mechanism by which mature adipocytes control adipogenesis during the development of obesity and suggest Piezo1-mediated adipocyte mechano-signalling as a mechanism to modulate obesity and its metabolic consequences.
Assuntos
Adipócitos/metabolismo , Fator 1 de Crescimento de Fibroblastos/metabolismo , Canais Iônicos/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Adipogenia/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Calorimetria , Células Cultivadas , Feminino , Fator 1 de Crescimento de Fibroblastos/genética , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Insulina/sangue , Interleucina-6/sangue , Canais Iônicos/genética , Masculino , Camundongos , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
PTEN acts as a phosphatase for PIP3 and negatively regulates the PI3K/AKT pathway, and p27(KIP1) is a cyclin-dependent kinase inhibitor that regulates the G1 to S-phase transition by binding to and regulating the activity of cyclin-dependent kinases. Genetic alterations of PTEN or CDKN1B (p27(KIP1)) are common in hematological malignancies. To better understand how mutations in these two genes might cooperate in leukemogenesis, we inactivated both genes in the hematological compartment in mice. Here, we show that the combined inactivation of Pten and Cdkn1b results in a more severe myeloproliferative neoplasm phenotype associated with lower hemoglobin, enlarged spleen and liver, and shorter lifespan compared to inactivation of Pten alone. More severe anemia and increased myeloid infiltration and destruction of the spleen contributed to the earlier death of these mice, and elevated p-AKT, cyclin D1, and cyclin D3 might contribute to the development of this phenotype. In conclusion, PTEN and p27(KIP1) cooperate in tumor suppression in the hematological compartment.