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1.
Cancer Immunol Res ; 3(6): 661-7, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25600437

RESUMO

Inefficient T-cell homing to tissues limits adoptive T-cell immunotherapy of solid tumors. αLß2 and α4ß1 integrins mediate trafficking of T cells into tissues via engagement of ICAM-1 and VCAM-1, respectively. Inhibiting protein kinase A (PKA)-mediated phosphorylation of α4 integrin in cells results in an increase in αLß2-mediated migration on mixed ICAM-1-VCAM-1 substrates in vitro, a phenomenon termed "integrin trans-regulation." Here, we created an α4(S988A)-bearing mouse, which precludes PKA-mediated α4 phosphorylation, to examine the effect of integrin trans-regulation in vivo. The α4(S988A) mouse exhibited a dramatic and selective increase in migration of lymphocytes, but not myeloid cells, to sites of inflammation. Importantly, we found that the α4(S988A) mice exhibited a marked increase in T-cell entry into and reduced growth of B16 melanomas, consistent with antitumor roles of infiltrating T cells and progrowth functions of tumor-associated macrophages. Thus, increased α4 trans-regulation of αLß2 integrin function biases leukocyte emigration toward lymphocytes relative to myeloid cells and enhances tumor immunity.


Assuntos
Integrinas/metabolismo , Neoplasias/imunologia , Neoplasias/metabolismo , Animais , Quimiotaxia de Leucócito/imunologia , Modelos Animais de Doenças , Humanos , Integrina alfa4/genética , Integrina alfa4/metabolismo , Integrinas/genética , Antígeno-1 Associado à Função Linfocitária/genética , Antígeno-1 Associado à Função Linfocitária/metabolismo , Camundongos , Camundongos Transgênicos , Mutação , Neoplasias/genética , Neoplasias/patologia , Ligação Proteica , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Carga Tumoral
2.
J Immunol ; 187(2): 851-60, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21670318

RESUMO

CD98 H chain (4F2 Ag, Slc3a2) was discovered as a lymphocyte-activation Ag. Deletion of CD98 H chain in B cells leads to complete failure of B cell proliferation, plasma cell formation, and Ab secretion. In this study, we examined the role of T cell CD98 in cell-mediated immunity and autoimmune disease pathogenesis by specifically deleting it in murine T cells. Deletion of T cell CD98 prevented experimental autoimmune diabetes associated with dramatically reduced T cell clonal expansion. Nevertheless, initial T cell homing to pancreatic islets was unimpaired. In sharp contrast to B cells, CD98-null T cells showed only modestly impaired Ag-driven proliferation and nearly normal homeostatic proliferation. Furthermore, these cells were activated by Ag, leading to cytokine production (CD4) and efficient cytolytic killing of targets (CD8). The integrin-binding domain of CD98 was necessary and sufficient for full clonal expansion, pointing to a role for adhesive signaling in T cell proliferation and autoimmune disease. When we expanded CD98-null T cells in vitro, they adoptively transferred diabetes, establishing that impaired clonal expansion was responsible for protection from disease. Thus, the integrin-binding domain of CD98 is required for Ag-driven T cell clonal expansion in the pathogenesis of an autoimmune disease and may represent a useful therapeutic target.


Assuntos
Doenças Autoimunes/genética , Doenças Autoimunes/prevenção & controle , Proliferação de Células , Cadeia Pesada da Proteína-1 Reguladora de Fusão/genética , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/patologia , Transferência Adotiva , Animais , Doenças Autoimunes/patologia , Células Clonais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/prevenção & controle , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/prevenção & controle , Humanos , Cadeias beta de Integrinas/química , Cadeias beta de Integrinas/fisiologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Estrutura Terciária de Proteína/genética , Subpopulações de Linfócitos T/transplante
3.
Diabetes ; 57(7): 1842-51, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18426864

RESUMO

OBJECTIVE: Many prevalent diseases of advanced societies, such as obesity-induced type 2 diabetes, are linked to indolent mononuclear cell-dependent inflammation. We previously proposed that blockade of alpha4 integrin signaling can inhibit inflammation while limiting mechanism-based toxicities of loss of alpha4 function. Thus, we hypothesized that mice bearing an alpha4(Y991A) mutation, which blocks signaling, would be protected from development of high-fat diet-induced insulin resistance. RESEARCH DESIGN AND METHODS: Six- to eight-week-old wild-type and alpha4(Y991A) C57Bl/6 male mice were placed on either a high-fat diet that derived 60% calories from lipids or a chow diet. Metabolic testing was performed after 16-22 weeks of diet. RESULTS: Alpha4(Y991A) mice were protected from development of high-fat diet-induced insulin resistance. This protection was conferred on wild-type mice by alpha4(Y991A) bone marrow transplantation. In the reverse experiment, wild-type bone marrow renders high-fat diet-fed alpha4(Y991A) acceptor animals insulin resistant. Furthermore, fat-fed alpha4(Y991A) mice showed a dramatic reduction of monocyte/macrophages in adipose tissue. This reduction was due to reduced monocyte/macrophage migration rather than reduced monocyte chemoattractant protein-1 production. CONCLUSIONS: Alpha4 integrins contribute to the development of HFD-induced insulin resistance by mediating the trafficking of monocytes into adipose tissue; hence, blockade of alpha4 integrin signaling can prevent the development of obesity-induced insulin resistance.


Assuntos
Gorduras na Dieta , Integrina alfa4/fisiologia , Obesidade/etiologia , Obesidade/fisiopatologia , Polimorfismo de Nucleotídeo Único , Tecido Adiposo/fisiologia , Tecido Adiposo/fisiopatologia , Substituição de Aminoácidos , Animais , Movimento Celular , Ácidos Graxos não Esterificados/sangue , Teste de Tolerância a Glucose , Insulina/sangue , Resistência à Insulina , Integrina alfa4/efeitos dos fármacos , Integrina alfa4/genética , Leptina/sangue , Lipídeos/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/fisiologia , Obesidade/sangue , Obesidade/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
4.
J Cell Biol ; 178(4): 701-11, 2007 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-17682053

RESUMO

Integrin-dependent assembly of the fibronectin (Fn) matrix plays a central role in vertebrate development. We identify CD98hc, a membrane protein, as an important component of the matrix assembly machinery both in vitro and in vivo. CD98hc was not required for biosynthesis of cellular Fn or the maintenance of the repertoire or affinity of cellular Fn binding integrins, which are important contributors to Fn assembly. Instead, CD98hc was involved in the cell's ability to exert force on the matrix and did so by dint of its capacity to interact with integrins to support downstream signals that lead to activation of RhoA small GTPase. Thus, we identify CD98hc as a membrane protein that enables matrix assembly and establish that it functions by interacting with integrins to support RhoA-driven contractility. CD98hc expression can vary widely; our data show that these variations in CD98hc expression can control the capacity of cells to assemble an Fn matrix, a process important in development, wound healing, and tumorigenesis.


Assuntos
Fibronectinas/metabolismo , Cadeia Pesada da Proteína-1 Reguladora de Fusão/metabolismo , Integrinas/metabolismo , Animais , Células-Tronco Embrionárias , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteína rhoA de Ligação ao GTP/metabolismo
5.
Proc Natl Acad Sci U S A ; 102(2): 355-60, 2005 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-15625115

RESUMO

Integrins regulate cellular behaviors through signaling pathways, including Rho GTPases and kinases. CD98 heterodimers, comprised of a heavy chain (CD98hc, SLC3A2) and one of several light chains, interact with integrins through CD98hc. CD98hc overexpression leads to anchorage-independent cell growth and tumorigenesis in 3T3 fibroblasts and activates certain integrin-regulated signaling pathways. To establish the biological function of CD98hc, we disrupted the gene and analyzed CD98hc-null cells. Here we report that CD98hc contributes to integrin-dependent cell spreading, cell migration, and protection from apoptosis. Furthermore, CD98hc is required for efficient adhesion-induced activation of Akt and Rac GTPase, major contributors to the integrin-dependent signals involved in cell survival and cell migration. CD98 promotes amino acid transport through its light chains; however, a CD98hc mutant that interacts with beta1 integrins, but not CD98 light chains, restored integrin-dependent signaling and protection from apoptosis. beta1 integrins are involved in the pathogenesis of certain cancers. CD98hc deletion markedly impaired the ability of embryonic stem cells to form teratocarcinomas in mice; teratocarcinoma formation was reconstituted by reexpression of CD98hc or of the mutant that interacts exclusively with integrins. Thus, CD98hc is an integrin-associated protein that mediates integrin-dependent signals, which promote tumorigenesis.


Assuntos
Cadeia Pesada da Proteína-1 Reguladora de Fusão/fisiologia , Integrinas/fisiologia , Transdução de Sinais/fisiologia , Animais , Apoptose , Adesão Celular , Movimento Celular , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/etiologia , Fosforilação
6.
J Biol Chem ; 277(23): 20887-94, 2002 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-11919182

RESUMO

The alpha(4) integrins play important roles in embryogenesis, hematopoiesis, cardiac development, and the immune responses. The alpha(4) integrin subunit is indispensable for these biological processes, possibly because the alpha(4) subunit regulates cellular functions differently from other integrin alpha subunits. We have previously reported that the alpha(4) cytoplasmic domain directly and tightly binds paxillin, an intracellular signaling adaptor molecule, and this interaction accounts for some of the unusual functional responses to alpha(4) integrin-mediated cell adhesion. We also have identified a conserved 9-amino acid region (Glu(983)-Tyr(991)) in the alpha(4) cytoplasmic domain that is sufficient for paxillin binding, and an alanine substitution at either Glu(983) or Tyr(991) within this region disrupted the alpha(4)-paxillin interaction and reversed the effects of the alpha(4) cytoplasmic domain on cell spreading and migration. In the current study, we have mapped the alpha(4)-binding site within paxillin using mutational analysis, and examined its effects on the alpha(4) tail-mediated functional responses. Here we report that sequences between residues Ala(176) and Asp(275) of paxillin are sufficient for binding to the alpha(4) tail. We found that the alpha(4) tail, paxillin, and FAT, the focal adhesion targeting domain of pp125(FAK), could form a ternary complex and that the alpha(4)-binding paxillin fragment, P(Ala(176)-Asp(275)), specifically blocked paxillin binding to the alpha(4) tail more efficiently than it blocked binding to FAT. Furthermore, when expressed in cells, this alpha(4)-binding paxillin fragment specifically inhibited the alpha(4) tail-stimulated cell migration. Thus, paxillin binding to the alpha(4) tail leads to enhanced cell migration and inhibition of the alpha(4)-paxillin interaction selectively blocks the alpha4-dependent cellular responses.


Assuntos
Antígenos CD/metabolismo , Movimento Celular/efeitos dos fármacos , Citoplasma/metabolismo , Proteínas do Citoesqueleto/metabolismo , Fragmentos de Peptídeos/farmacologia , Fosfoproteínas/metabolismo , Animais , Antígenos CD/fisiologia , Sítios de Ligação , Células CHO , Cricetinae , Proteínas do Citoesqueleto/química , Proteína-Tirosina Quinases de Adesão Focal , Integrina alfa4 , Paxilina , Fosfoproteínas/química , Ligação Proteica , Proteínas Tirosina Quinases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo
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