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1.
Stem Cells ; 35(7): 1733-1746, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28436144

RESUMO

Muscle regeneration depends on satellite cells (SCs), quiescent precursors that, in consequence of injury or in pathological states such as muscular dystrophies, activate, proliferate, and differentiate to repair the damaged tissue. A subset of SCs undergoes self-renewal, thus preserving the SC pool and its regenerative potential. Unacylated ghrelin (UnAG) is a circulating hormone that protects muscle from atrophy, promotes myoblast differentiation, and enhances ischemia-induced muscle regeneration. Here we show that UnAG increases SC activity and stimulates Par polarity complex/p38-mediated asymmetric division, fostering both SC self-renewal and myoblast differentiation. Because of those activities on different steps of muscle regeneration, we hypothesized a beneficial effect of UnAG in mdx dystrophic mice, in which the absence of dystrophin leads to chronic muscle degeneration, defective muscle regeneration, fibrosis, and, at later stages of the pathology, SC pool exhaustion. Upregulation of UnAG levels in mdx mice reduces muscle degeneration, improves muscle function, and increases dystrophin-null SC self-renewal, maintaining the SC pool. Our results suggest that UnAG has significant therapeutic potential for preserving the muscles in dystrophies. Stem Cells 2017;35:1733-1746.


Assuntos
Distrofina/genética , Grelina/genética , Músculo Esquelético/metabolismo , Distrofia Muscular Animal/metabolismo , Regeneração/genética , Células Satélites de Músculo Esquelético/metabolismo , Acilação , Animais , Contagem de Células , Diferenciação Celular , Distrofina/metabolismo , Fibrose , Regulação da Expressão Gênica , Grelina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Músculo Esquelético/patologia , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/patologia , Fenótipo , Células Satélites de Músculo Esquelético/patologia , Transdução de Sinais , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
2.
Front Cell Dev Biol ; 4: 140, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27965956

RESUMO

Diacylglycerol kinases (DGKs) terminate diacylglycerol (DAG) signaling and promote phosphatidic acid (PA) production. Isoform specific regulation of DGKs activity and localization allows DGKs to shape the DAG and PA gradients. The capacity of DGKs to constrain the areas of DAG signaling is exemplified by their role in defining the contact interface between T cells and antigen presenting cells: the immune synapse. Upon T cell receptor engagement, both DGK α and ζ metabolize DAG at the immune synapse thus constraining DAG signaling. Interestingly, their activity and localization are not fully redundant because DGKζ activity metabolizes the bulk of DAG in the cell, whereas DGKα limits the DAG signaling area localizing specifically at the periphery of the immune synapse. When DGKs terminate DAG signaling, the local PA production defines a new signaling domain, where PA recruits and activates a second wave of effector proteins. The best-characterized example is the role of DGKs in protrusion elongation and cell migration. Indeed, upon growth factor stimulation, several DGK isoforms, such as α, ζ, and γ, are recruited and activated at the plasma membrane. Here, local PA production controls cell migration by finely modulating cytoskeletal remodeling and integrin recycling. Interestingly, DGK-produced PA also controls the localization and activity of key players in cell polarity such as aPKC, Par3, and integrin ß1. Thus, T cell polarization and directional migration may be just two instances of the general contribution of DGKs to the definition of cell polarity by local specification of membrane identity signaling.

3.
Sci Transl Med ; 8(321): 321ra7, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26764158

RESUMO

X-linked lymphoproliferative disease (XLP-1) is an often-fatal primary immunodeficiency associated with the exuberant expansion of activated CD8(+) T cells after Epstein-Barr virus (EBV) infection. XLP-1 is caused by defects in signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), an adaptor protein that modulates T cell receptor (TCR)-induced signaling. SAP-deficient T cells exhibit impaired TCR restimulation-induced cell death (RICD) and diminished TCR-induced inhibition of diacylglycerol kinase α (DGKα), leading to increased diacylglycerol metabolism and decreased signaling through Ras and PKCθ (protein kinase Cθ). We show that down-regulation of DGKα activity in SAP-deficient T cells restores diacylglycerol signaling at the immune synapse and rescues RICD via induction of the proapoptotic proteins NUR77 and NOR1. Pharmacological inhibition of DGKα prevents the excessive CD8(+) T cell expansion and interferon-γ production that occur in SAP-deficient mice after lymphocytic choriomeningitis virus infection without impairing lytic activity. Collectively, these data highlight DGKα as a viable therapeutic target to reverse the life-threatening EBV-associated immunopathology that occurs in XLP-1 patients.


Assuntos
Diacilglicerol Quinase/antagonistas & inibidores , Transtornos Linfoproliferativos/imunologia , Transtornos Linfoproliferativos/patologia , Animais , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/metabolismo , Morte Celular/efeitos dos fármacos , Citocinas/biossíntese , Diacilglicerol Quinase/metabolismo , Inativação Gênica/efeitos dos fármacos , Humanos , Sinapses Imunológicas/efeitos dos fármacos , Sinapses Imunológicas/metabolismo , Ativação Linfocitária , Contagem de Linfócitos , Transtornos Linfoproliferativos/tratamento farmacológico , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinonas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/deficiência , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/metabolismo , Tiazóis/farmacologia , Proteínas ras/metabolismo
4.
PLoS One ; 9(6): e97144, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24887021

RESUMO

Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5ß1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of ß1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and ß1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - ß1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Quimiocina CXCL12/farmacologia , Diacilglicerol Quinase/metabolismo , Integrina beta1/metabolismo , Proteína Quinase C/metabolismo , Transdução de Sinais/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Metaloproteinase 9 da Matriz/metabolismo , Invasividade Neoplásica , Transporte Proteico/efeitos dos fármacos , Pseudópodes/efeitos dos fármacos , Pseudópodes/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo
5.
J Immunol ; 192(10): 4921-31, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24729612

RESUMO

Vascular endothelial cells (ECs) and several cancer cells express B7h, which is the ligand of the ICOS T cell costimulatory molecule. We have previously shown that B7h triggering via a soluble form of ICOS (ICOS-Fc) inhibits the adhesion of polymorphonuclear and tumor cell lines to HUVECs; thus, we suggested that ICOS-Fc may act as an anti-inflammatory and antitumor agent. Because cancer cell migration and angiogenesis are crucial for metastasis dissemination, the aim of this work was to evaluate the effect of ICOS-Fc on the migration of cancer cells and ECs. ICOS-Fc specifically inhibited the migration of HUVECs, human dermal lymphatic ECs, and the HT29, HCT116, PC-3, HepG2, JR8, and M14 tumor cell lines expressing high levels of B7h, whereas it was ineffective in the RPMI7932, PCF-2, LM, and BHT-101 cell lines expressing low levels of B7h. Furthermore, ICOS-Fc downmodulated hepatocyte growth factor facilitated the epithelial-to-mesenchymal transition in HepG2 cells. Moreover, ICOS-Fc downmodulated the phosphorylation of focal adhesion kinase and the expression of ß-Pix in both HUVECs and tumor cell lines. Finally, treatment with ICOS-Fc inhibited the development of lung metastases upon injection of NOD-SCID-IL2Rγnull mice with CF-PAC1 cells, as well as C57BL/6 mice with B16-F10 cells. Therefore, the B7h-ICOS interaction may modulate the spread of cancer metastases, which suggests the novel use of ICOS-Fc as an immunomodulatory drug. However, in the B16-F10-metastasized lungs, ICOS-Fc also increased IL-17A/RORc and decreased IL-10/Foxp3 expression, which indicates that it also exerts positive effects on the antitumor immune response.


Assuntos
Movimento Celular/imunologia , Ligante Coestimulador de Linfócitos T Induzíveis/imunologia , Neoplasias Pulmonares/imunologia , Animais , Células Hep G2 , Xenoenxertos , Células Endoteliais da Veia Umbilical Humana , Humanos , Fragmentos Fc das Imunoglobulinas/genética , Fragmentos Fc das Imunoglobulinas/imunologia , Ligante Coestimulador de Linfócitos T Induzíveis/genética , Proteína Coestimuladora de Linfócitos T Induzíveis/genética , Proteína Coestimuladora de Linfócitos T Induzíveis/imunologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/secundário , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Metástase Neoplásica , Transplante de Neoplasias , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/farmacologia
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