Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Leukoc Biol ; 114(3): 202-204, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37431614

RESUMO

FasL has divergent roles in both causing graft-vs-host disease and preventing this condition, which depends on the immune cell type that expresses it.


Assuntos
Doença Enxerto-Hospedeiro , Humanos , Proteína Ligante Fas/metabolismo , Doença Aguda
2.
Mol Immunol ; 160: 12-19, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37295053

RESUMO

Hypoxia inducible factor-1ɑ (HIF-1ɑ) is the regulatory subunit of the HIF-1 transcription factor that is a regulator of cell physiological responses to hypoxia. However, the biological function and regulatory mechanisms controlling HIF-1α in normoxia are poorly understood. Here, we first examined the role of HIF-1α in the inflammatory activation of A549 human lung carcinoma cells in normoxia. Inactivation of the HIF-1α gene by CRISPR/Cas9 reduced the secretion of CXCL8 induced by stimulation with a cytokine mixture (CM) consisting of IL-1, TNFα and IFNγ. We next determined that cytokines act co-operatively to induce expression and nuclear accumulation of HIF-1α. To investigate the signalling mechanisms by which cytokines induce HIF-1α in normoxia, pharmacological inhibitors against the Jak/STAT, PI3K, NFκB, MEK/ERK, and JNK pathways were used. Inhibition of the Jak/STAT and JNK pathways inhibited the induction and nuclear accumulation of HIF-1ɑ by cytokines. Furthermore, siRNA knockdown of STAT1 and JNK also reduced the induction of HIF-1α by cytokines. Finally, pharmacological inhibition of these two pathways also blocked the trans-activation of HIF-1. These findings have implications for understanding the role and regulatory mechanisms of HIF-1ɑ in inflammation and cell biology.


Assuntos
Carcinoma , Neoplasias Pulmonares , Humanos , Citocinas/metabolismo , Sistema de Sinalização das MAP Quinases , Neoplasias Pulmonares/metabolismo , Hipóxia/metabolismo , Pulmão/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia Celular , Fator de Transcrição STAT1/metabolismo
3.
Transplantation ; 106(11): 2155-2165, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35485447

RESUMO

BACKGROUND: The gut microbiota affects immune responses that cause organ transplant rejection, but the mechanisms by which this occurs remain poorly understood. METHODS: We have examined, in a murine model, how disruption of the gut microbiota with antibiotics early in life alters this microbial community later in life to affect immune responses that injure vascular allografts. RESULTS: Analysis of 16S rRNA and whole genome sequencing of the gut microbiota demonstrated that early life disruption of this microbial community with antibiotics caused a reduction in taxa and enzymatic genes involved in the synthesis of acetate, an immunoregulatory metabolite in mice and humans. When allograft vascular injury was examined, early life disruption of the gut microbiota increased neutrophil accumulation and related medial injury of transplanted arteries. Normalizing the gut microbiota by co-housing and oral administration of acetate prevented neutrophil-mediated vascular allograft injury. CONCLUSIONS: Dysbiosis of the gut microbiome that reduces its production of the immunoregulatory metabolite acetate exacerbates neutrophil-mediated allograft vascular injury.


Assuntos
Microbioma Gastrointestinal , Lesões do Sistema Vascular , Humanos , Camundongos , Feminino , Animais , Disbiose , RNA Ribossômico 16S/genética , Neutrófilos , Lesões do Sistema Vascular/complicações , Antibacterianos , Imunidade , Acetatos , Aloenxertos
4.
Nat Biomed Eng ; 5(10): 1202-1216, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34373602

RESUMO

Systemic immunosuppression for the mitigation of immune rejection after organ transplantation causes adverse side effects and constrains the long-term benefits of the transplanted graft. Here we show that protecting the endothelial glycocalyx in vascular allografts via the enzymatic ligation of immunosuppressive glycopolymers under cold-storage conditions attenuates the acute and chronic rejection of the grafts after transplantation in the absence of systemic immunosuppression. In syngeneic and allogeneic mice that received kidney transplants, the steric and immunosuppressive properties of the ligated polymers largely protected the transplanted grafts from ischaemic reperfusion injury, and from immune-cell adhesion and thereby immunocytotoxicity. Polymer-mediated shielding of the endothelial glycocalyx following organ procurement should be compatible with clinical procedures for transplant preservation and perfusion, and may reduce the damage and rejection of transplanted organs after surgery.


Assuntos
Glicocálix , Rejeição de Enxerto , Aloenxertos , Animais , Rejeição de Enxerto/prevenção & controle , Imunossupressores , Camundongos , Polímeros
5.
Am J Physiol Cell Physiol ; 320(4): C554-C565, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33471622

RESUMO

IL-6 affects tissue protective/reparative and inflammatory properties of vascular endothelial cells (ECs). This cytokine can signal to cells through classic and trans-signaling mechanisms, which are differentiated based on the expression of IL-6 receptor (IL-6R) on the surface of target cells. The biological effects of these IL-6-signaling mechanisms are distinct and have implications for vascular pathologies. We have directly compared IL-6 classic and trans-signaling in ECs. Human ECs expressed IL-6R in culture and in situ in coronary arteries from heart transplants. Stimulation of human ECs with IL-6, to model classic signaling, triggered the activation of phosphatidylinositol 3-kinase (PI3K)-Akt and ERK1/2 signaling pathways, whereas stimulation with IL-6 + sIL-6R, to model trans-signaling, triggered activation of STAT3, PI3K-Akt, and ERK1/2 pathways. IL-6 classic signaling reduced persistent injury of ECs in an allograft model of vascular rejection and inhibited cell death induced by growth factor withdrawal. When inflammatory effects were examined, IL-6 classic signaling did not induce ICAM or CCL2 expression but was sufficient to induce secretion of CXCL8 and support transmigration of neutrophil-like cells. IL-6 trans-signaling induced all inflammatory effects studied. Our findings show that IL-6 classic and trans-signaling have overlapping but distinct properties in controlling EC survival and inflammatory activation. This has implications for understanding the effects of IL-6 receptor-blocking therapies as well as for vascular responses in inflammatory and immune conditions.


Assuntos
Aorta Abdominal/efeitos dos fármacos , Receptor gp130 de Citocina/agonistas , Células Endoteliais/efeitos dos fármacos , Rejeição de Enxerto/prevenção & controle , Interleucina-6/farmacologia , Receptores de Interleucina-6/agonistas , Adulto , Idoso , Animais , Aorta Abdominal/metabolismo , Aorta Abdominal/patologia , Aorta Abdominal/transplante , Células Cultivadas , Receptor gp130 de Citocina/metabolismo , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Células Endoteliais/transplante , Feminino , Rejeição de Enxerto/metabolismo , Rejeição de Enxerto/patologia , Humanos , Mediadores da Inflamação/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores de Interleucina-6/metabolismo , Transdução de Sinais
6.
Clin Lab Med ; 39(1): 185-195, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30709506

RESUMO

The microbiota is a community of microbes that colonizes body surfaces. It has many effects that influence immune activation and regulation. The success of organ transplantation is limited by rejection of grafts by the immune system so it is important to understand how immunologic responses are controlled in this setting. This review discusses the immunologic effects of the microbiota and how this microbial community may affect organ transplant rejection.


Assuntos
Microbioma Gastrointestinal/imunologia , Rejeição de Enxerto/microbiologia , Fatores Imunológicos/uso terapêutico , Transplante de Órgãos , Humanos , Fatores Imunológicos/efeitos adversos , Terapia de Imunossupressão
7.
Free Radic Biol Med ; 130: 278-287, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30391674

RESUMO

The production of nitric oxide (NO) by inducible NO synthase (iNOS) and the regulation of gene expression by hypoxia-inducible factors (HIFs) are important for many aspects of human cell biology. However, little is known about whether iNOS expression is controlled by HIFs in human cells. Stimulation of A549 human lung epithelial cells with cytokines (TNF, IL-1 and IFNγ) increased the nuclear accumulation of HIF-1 in normoxic conditions. Activation of HIF-1 by hypoxia or CoCl2 was not sufficient to induce iNOS expression. However, pharmacological inhibition of HIF-1 reduced the induction of iNOS expression in A549 cells and primary human astrocytes. Moreover, elimination of HIF-1α expression and activity by CRISPR/Cas9 gene editing significantly reduced the induction of human iNOS gene promoter, mRNA and protein expression by cytokine stimulation. Three putative hypoxia response elements (HRE) are present within the human iNOS gene promoter and elimination of an HRE at -4981 bp reduced the induction of human iNOS promoter activity in response to cytokine stimulation. These findings establish an important role for HIF-1α in the induction of human iNOS gene expression in response to cytokine stimulation.


Assuntos
Hipóxia Celular/genética , Citocinas/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Óxido Nítrico Sintase Tipo II/genética , Células A549 , Astrócitos/metabolismo , Sistemas CRISPR-Cas/genética , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Interferon gama/efeitos dos fármacos , Interferon gama/genética , Interferon gama/farmacologia , Interleucina-1/farmacologia , Óxido Nítrico/biossíntese , Óxido Nítrico/metabolismo , Regiões Promotoras Genéticas/genética , Elementos de Resposta/genética , Fator de Necrose Tumoral alfa/farmacologia
8.
Transplantation ; 102(7): 1085-1095, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29538261

RESUMO

BACKGROUND: The gut microbiota influences many immunological processes but how its disruption affects transplant rejection is poorly understood. METHODS: Interposition grafting of aortic segments was used to examine vascular rejection. The gut microbiota was disrupted in graft recipients using an antibiotic cocktail (ampicillin, vancomycin, metronidazole, neomycin sulfate) in their drinking water. RESULTS: Treatment of mice with antibiotics severely reduced total bacterial content in the intestine and disrupted the bacterial composition. Short-term treatment of mice for only the first 3 weeks of life resulted in the population of the intestine in mature mice with bacterial communities that were mildly different from untreated mice, containing slightly more Clostridia and less Bacteroides. Antibiotic disruption of the gut microbiota of graft recipients, either for their entire life or only during the first 3 weeks of life, resulted in increased medial injury of allograft arteries that is reflective of acute vascular rejection but did not affect intimal thickening reflective of transplant arteriosclerosis. Exacerbated vascular rejection resulting from disruption of the gut microbiota was related to increased infiltration of allograft arteries by neutrophils. CONCLUSIONS: Disruption of the gut microbiota early in life results in exacerbation of immune responses that cause acute vascular rejection.


Assuntos
Antibacterianos/efeitos adversos , Bactérias/imunologia , Disbiose/imunologia , Microbioma Gastrointestinal/efeitos dos fármacos , Rejeição de Enxerto/imunologia , Enxerto Vascular/efeitos adversos , Animais , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Modelos Animais de Doenças , Disbiose/induzido quimicamente , Disbiose/microbiologia , Feminino , Microbioma Gastrointestinal/imunologia , Rejeição de Enxerto/microbiologia , Humanos , Mucosa Intestinal/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fatores de Tempo
9.
Cardiovasc Pathol ; 33: 55-61, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29414433

RESUMO

Giant cell arteritis (GCA) is the most common vasculitis in adults affecting large and medium-sized arteries. IL-6 and T cell accumulation within the arterial wall contribute to the pathogenesis of GCA, and blockade of IL-6 activity is efficacious in its treatment. We examined the relationship between levels of IL-6 expression and immunological processes that control the expansion of T cells in GCA-positive temporal artery biopsies. CD4 T cells accumulated in clusters within the media and deep intima of all GCA lesions. There was a significant positive correlation between the expression of IL-6 mRNA and increased frequency of proliferating CD4 T cells. The expansion of T cells can be inhibited by T regs but IL-6 expression was not correlated with differences in T reg accumulation. Increased IL-6 levels were also significantly correlated with lower frequencies of CD4 T cells undergoing apoptotic cell death. In conclusion, IL-6 may contribute to the accumulation of CD4 T cells in GCA by supporting their proliferation and survival within the arterial wall through mechanisms that are independent of effects on local T reg expansion.


Assuntos
Linfócitos T CD4-Positivos/química , Proliferação de Células , Arterite de Células Gigantes/genética , Arterite de Células Gigantes/patologia , Interleucina-6/genética , Ativação Linfocitária , Artérias Temporais/química , Artérias Temporais/patologia , Idoso , Idoso de 80 Anos ou mais , Apoptose , Linfócitos T CD4-Positivos/imunologia , Sobrevivência Celular , Feminino , Arterite de Células Gigantes/imunologia , Humanos , Masculino , RNA Mensageiro/genética , Linfócitos T Reguladores/química , Linfócitos T Reguladores/imunologia , Artérias Temporais/imunologia
10.
Front Microbiol ; 8: 2706, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29403452

RESUMO

Aspergillus fumigatus is a filamentous fungus that can cause a life-threatening invasive pulmonary aspergillosis (IPA) in immunocompromised individuals. We previously characterized an exo-sialidase from A. fumigatus that prefers the sialic acid substrate, 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (Kdn); hence it is a Kdnase. Sialidases are known virulence factors in other pathogens; therefore, the goal of our study was to evaluate the importance of Kdnase in A. fumigatus. A kdnase knockout strain (Δkdnase) was unable to grow on medium containing Kdn and displayed reduced growth and abnormal morphology. Δkdnase was more sensitive than wild type to hyperosmotic conditions and the antifungal agent, amphotericin B. In contrast, Δkdnase had increased resistance to nikkomycin, Congo Red and Calcofluor White indicating activation of compensatory cell wall chitin deposition. Increased cell wall thickness and chitin content in Δkdnase were confirmed by electron and immunofluorescence microscopy. In a neutropenic mouse model of invasive aspergillosis, the Δkdnase strain had attenuated virulence and a significantly lower lung fungal burden but only in animals that received liposomal amphotericin B after spore exposure. Macrophage numbers were almost twofold higher in lung sections from mice that received the Δkdnase strain, possibly related to higher survival of macrophages that internalized the Δkdnase conidia. Thus, A. fumigatus Kdnase is important for fungal cell wall integrity and virulence, and because Kdnase is not present in the host, it may represent a potential target for the development of novel antifungal agents.

11.
Transplantation ; 100(11): 2332-2341, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27222933

RESUMO

BACKGROUND: IL-6 is an inflammatory cytokine that controls effector T cell responses but the mechanisms by which it controls allogeneic immune responses and vascular rejection that leads to transplant arteriosclerosis (TA) are poorly understood. METHODS: We have examined the mechanism by which IL-6 contributes to the pathogenesis of vascular rejection and TA using a murine aortic interposition model of vascular rejection. RESULTS: The absence of IL-6 production from artery graft cells reduced the development of vascular rejection and arteriosclerotic thickening. There was no apparent effect of donor-derived IL-6 on endothelial cell integrity or on the intimal accumulation of smooth muscle cells, macrophages, and anti-donor antibodies. However, reduced vascular pathology in IL-6 artery grafts was accompanied by a significant reduction in the accumulation of CD4 and CD8 T cells. Further, the absence of graft-derived IL-6 resulted in a significant decrease in the activation and proliferation of alloreactive CD4 and CD8 T cells after transplantation as well as in a marked increase in cell death of effector T cells. Alloreactive effector T cells that expanded in the absence of IL-6 were also more susceptible to Fas-mediated activation-induced cell death in vitro. Finally, systemic neutralization of IL-6R did not reduce arteriosclerotic thickening but reduced endothelial integrity in allograft arteries, indicating differential effects of specific elimination of IL-6 in graft cells and systemic IL-6 neutralization. CONCLUSIONS: Donor-derived IL-6 amplifies the expansion of allogeneic T cell responses that cause vascular rejection and TA by increasing T cell proliferation and preventing Fas-mediated T cell death.


Assuntos
Arteriosclerose/etiologia , Rejeição de Enxerto/etiologia , Transplante de Coração/efeitos adversos , Interleucina-6/farmacologia , Isoantígenos/imunologia , Ativação Linfocitária/efeitos dos fármacos , Linfócitos T/imunologia , Animais , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Receptores de Interleucina-6/fisiologia
12.
Arterioscler Thromb Vasc Biol ; 34(6): 1290-7, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24700126

RESUMO

OBJECTIVE: Bim is a proapoptotic Bcl-2 protein known to downregulate immune responses and to also be required for antigen-induced T-cell activation. However, it is not known how the effect of Bim on these offsetting processes determines the outcome of allogeneic immune responses. We have defined the role of Bim in regulating alloantigen-driven T-cell responses in a model of vascular rejection. APPROACH AND RESULTS: Bim was required for proliferation of CD4 and CD8 T cells, and for interleukin-2 production, in T cells stimulated with alloantigen in vitro. Moreover, a partial reduction in Bim expression was sufficient to attenuate T-cell activation, whereas a complete elimination of Bim was required to prevent CD4 T-cell death in response to cytokine withdrawl. When alloimmune-mediated vascular rejection was examined using an aortic interposition model, there was significantly less intimal thickening in Bim(+/-), but not Bim(-/-), graft recipients. T-cell proliferation in response to allograft arteries was significantly reduced in both Bim(+/-) and Bim(-/-) mice, but cell death was attenuated only in Bim(-/-) animals. CONCLUSIONS: Bim controls both T-cell activation and death in response to alloantigen stimulation. These processes act cooperatively to determine the outcome of immune responses in allograft arteries.


Assuntos
Proteínas Reguladoras de Apoptose/fisiologia , Apoptose , Isoantígenos/imunologia , Ativação Linfocitária , Proteínas de Membrana/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Linfócitos T/imunologia , Doenças Vasculares/etiologia , Animais , Proteína 11 Semelhante a Bcl-2 , Citocinas/fisiologia , Feminino , Rejeição de Enxerto/etiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Transplante Homólogo
13.
Front Immunol ; 5: 684, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25628623

RESUMO

Solid organ transplantation is the only treatment for end-stage organ failure but this life-saving procedure is limited by immune-mediated rejection of most grafts. Blood vessels within transplanted organs are targeted by the immune system and the resultant vascular damage is a main contributor to acute and chronic graft failure. The vasculature is a unique tissue with specific immunological properties. This review discusses the interactions of the immune system with blood vessels in transplanted organs and how these interactions lead to the development of transplant arteriosclerosis, a leading cause of heart transplant failure.

14.
J Biol Chem ; 288(22): 15677-86, 2013 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-23599434

RESUMO

The production of nitric oxide (NO) by inducible NO synthase (iNOS) regulates many aspects of physiology and pathology. The expression of iNOS needs to be tightly regulated to balance the broad ranging properties of NO. We have investigated the feedback regulation of cytokine-induced iNOS expression by NO in human cells. The pharmacological inhibition of iNOS activity reduced iNOS protein levels in response to cytokine stimulation in a human epithelial cell line (A549 cells) as well as in primary human astrocytes and bronchial epithelial cells. The addition of exogenous NO using a NO donor prevented the reduction in iNOS levels caused by blockade of iNOS activity. Examination of signaling pathways affected by iNOS indicated that NO S-nitrosylated Ras. Transfection of cells with a S-nitrosylation-resistant Ras mutant reduced iNOS protein levels, indicating a role for this Ras modification in the amplification of iNOS levels. Further, the induction of iNOS protein levels correlated with the late activation of the phosphatidylinositol 3-kinase/Akt and mammalian target of rapamycin (mTOR) pathways, and inhibition of these signaling molecules reduced iNOS levels. Altogether, our findings reveal a previously unknown regulatory pathway that amplifies iNOS expression in human cells.


Assuntos
Células Epiteliais/metabolismo , Óxido Nítrico Sintase Tipo II/biossíntese , Óxido Nítrico/metabolismo , Transdução de Sinais/fisiologia , Proteínas ras/metabolismo , Linhagem Celular , Indução Enzimática/fisiologia , Células Epiteliais/citologia , Humanos , Óxido Nítrico/genética , Óxido Nítrico Sintase Tipo II/genética , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Proteínas ras/genética
15.
J Immunol ; 188(3): 1544-50, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22219320

RESUMO

IL-17 is a signature cytokine of Th17 cells, a recently described subset of effector CD4 T cells implicated in the development of several pathologies. We have examined the role of IL-17 in regulating endothelial NO synthase (eNOS) expression in human vascular endothelial cells (ECs) because of the key role of eNOS in determining the pathological outcome of immune-mediated vascular diseases. In cultured ECs, IL-17 increased expression of eNOS, eNOS phosphorylation at Ser(1177), and NO production. The induction of eNOS expression by IL-17 was prevented by the pharmacological inhibition of NF-κB, MEK, and JNK, as well as by small interfering RNA-mediated gene silencing of these signaling pathways. The expression of IL-17 was then examined by immunohistochemistry in human arteries affected by transplant vasculopathy (TV), a vascular condition that is a leading reflection of chronic heart transplant rejection. IL-17 was expressed by infiltrating leukocytes in the intima of arteries with TV, and the majority of IL-17-positive cells were T cells. The number of IL-17-positive cells was not correlated with the intima/media ratio, but was negatively correlated with the amount of luminal occlusion. There was also a significant positive correlation between the number of IL-17-positive cells and the density of eNOS-expressing luminal ECs in arteries with TV. Altogether, these findings show that IL-17 induces the expression of eNOS in human ECs and that this may facilitate outward expansion of arteries afflicted with TV.


Assuntos
Células Endoteliais/metabolismo , Interleucina-17/farmacologia , Óxido Nítrico Sintase Tipo III/genética , Ativação Transcricional/efeitos dos fármacos , Doenças Vasculares/imunologia , Artérias , Células Endoteliais/imunologia , Endotélio Vascular/imunologia , Endotélio Vascular/metabolismo , Transplante de Coração/efeitos adversos , Humanos , Interleucina-17/análise , Óxido Nítrico Sintase Tipo III/biossíntese , Linfócitos T , Doenças Vasculares/etiologia
16.
J Biol Chem ; 286(24): 21137-44, 2011 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-21518761

RESUMO

The nature of inflammatory signals determines the outcome of T cell responses. However, little is known about how inflammatory cytokines provided to human CD8 T cells during activation affects their susceptibility to post-activation cell death. We have examined and compared the effects of the inflammatory cytokine IL-12, as well as the combination of IL-1, IL-6, and IL-23 (IL-1/6/23) on the susceptibility of primary human CD8 T cells to post-activation cell death. Human CD8 T cells activated in the presence of IL-1/6/23 underwent significantly less cell death after activation as compared with those activated in IL-12. This was due to reduced susceptibility to Fas-mediated activation-induced cell death (AICD). Mechanistically, the reduced level of cell death in CD8 T cells activated in IL-1/6/23 was a result of a low level of FasL expression and high level of c-FLIP(S) expression. When the effect of IL-1, IL-6, and IL-23 individually was examined, IL-1 or IL-6 alone was sufficient to inhibit CD8 T cell death that occurs after activation in IL-12. IL-1, but not IL-6, inhibited expression of FasL, whereas IL-6, but not IL-1, increased c-FLIP(S) expression. Our findings show that the presence of IL-1 and/or IL-6 during activation of human CD8 T cells attenuates Fas-mediated AICD, whereas IL-12 increases the susceptibility of activated CD8 T cells to this form of cell death.


Assuntos
Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/metabolismo , Linfócitos T CD8-Positivos/citologia , Citocinas/metabolismo , Proteína Ligante Fas/metabolismo , Regulação da Expressão Gênica , Receptor fas/metabolismo , Apoptose , Morte Celular , Sobrevivência Celular , Humanos , Inflamação , Interleucina-1/metabolismo , Interleucina-12/metabolismo , Interleucina-6/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo
17.
Arterioscler Thromb Vasc Biol ; 31(5): 1177-84, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21330602

RESUMO

OBJECTIVE: CD155 is a cell surface protein that has recently been described to exert immune regulatory functions. We have characterized the expression of CD155 on human vascular endothelial cells (ECs) and examined its role in the regulation of T-cell activation. METHODS AND RESULTS: CD155 was expressed on resting human vascular ECs and was upregulated in an interferon-γ (IFNγ)-dependent manner. When the function of CD155 in regulating T-cell activation was examined, antibody-mediated neutralization of CD155 did not affect CD8 T-cell proliferation in response to stimulation with ECs. However, neutralization of CD155 activity or small interfering RNA-mediated inhibition of CD155 expression in ECs increased expression of IFNγ and cytotoxic effector function in activated CD8 T cells. CONCLUSIONS: CD155 is an IFNγ-inducible immune regulatory protein on the surface of human ECs that attenuates the acquisition of effector functions in CD8 T cells.


Assuntos
Proteínas ADAM/metabolismo , Linfócitos T CD8-Positivos/imunologia , Comunicação Celular , Células Endoteliais/imunologia , Ativação Linfocitária , Proteínas de Membrana/metabolismo , Proteínas ADAM/genética , Anticorpos Neutralizantes , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Humanos , Interferon gama/metabolismo , Interleucina-1alfa/metabolismo , Interleucina-6/metabolismo , Proteínas de Membrana/genética , Interferência de RNA , Linfócitos T Citotóxicos/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima
18.
J Immunol ; 185(2): 1283-94, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20562257

RESUMO

Atherosclerosis of native coronary arteries and graft arteriosclerosis in transplanted hearts are characterized by activation of innate and adaptive immune responses. Nucleic acids generated by infections or cell death have been detected within arteriosclerotic lesions, and it is known that microbial and synthetic nucleic acids evoke inflammatory responses in cultured vascular cells. In this study, we report that model RNA, but not DNA, instigated robust cytokine and chemokine production from intact human coronary arteries containing both intrinsic vascular cells and resident/infiltrating leukocytes. An ssRNA analog induced TNF-alpha and IFN-gamma-induced protein of 10 kDa secretion by isolated human PBMCs, but not vascular cells. Conversely, synthetic dsRNA induced these inflammatory mediators by vascular cells, but not PBMCs. IFN-gamma, a cytokine linked to atherosclerosis and graft arteriosclerosis, potentiated the inflammatory responses of intact arteries and cultured vascular smooth muscle cells (VSMCs) to polyinosinic:polycytidylic acid [poly(I:C)] and was necessary for inflammatory responses of VSMC to self-RNA derived from autologous cells. IFN-gamma also induced the expression of TLR3, melanoma differentiation-associated gene 5, and retinoic acid-inducible gene I dsRNA receptors. Small interfering RNA knockdown revealed that TLR3 mediated VSMC activation by poly(I:C), whereas melanoma differentiation-associated gene 5 was more important for VSMC stimulation by self-RNA. IFN-gamma-mediated induction of dsRNA receptors and priming for inflammatory responses to poly(I:C) was confirmed in vivo using immunodeficient mice bearing human coronary artery grafts. These findings suggest that IFN-gamma, and by inference adaptive immunity, sensitizes the vasculature to innate immune activators, such as RNA, and activation of IFN-gamma-primed vascular cells by exogenous or endogenous sources of RNA may contribute to the inflammatory milieu of arteriosclerosis.


Assuntos
Vasos Coronários/imunologia , RNA Helicases DEAD-box/metabolismo , Interferon gama/imunologia , Miócitos de Músculo Liso/imunologia , Poli I-C/farmacologia , Receptor 2 Toll-Like/metabolismo , Animais , Células Cultivadas , Quimiocina CXCL10/metabolismo , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/transplante , RNA Helicases DEAD-box/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Immunoblotting , Técnicas In Vitro , Helicase IFIH1 Induzida por Interferon , Interferon gama/genética , Interferon gama/metabolismo , Camundongos , Camundongos SCID , Músculo Liso Vascular/citologia , Músculo Liso Vascular/imunologia , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Interferência de RNA , RNA de Cadeia Dupla/imunologia , RNA de Cadeia Dupla/metabolismo , RNA de Cadeia Dupla/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Receptor 2 Toll-Like/genética , Transplante Heterólogo , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima
19.
J Heart Lung Transplant ; 27(12): 1333-9, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19059114

RESUMO

BACKGROUND: We reported previously that inducible nitric oxide synthase (iNOS) expression in graft-infiltrating human T cells that is confined to the bystander population contributes to T- cell-mediated rejection of allograft arteries in a humanized mouse model. Herein we examine whether CXCL12, a chemokine thought to contribute to recruitment of bystander T cells, induces iNOS in human CD8 T cells. METHODS: Human CD8 T cells were treated with CXCL12 and iNOS expression was examined. Also, human allograft arteries were immunohistochemically stained for iNOS and CD8, and adjacent sections stained for CXCL12 to determine their localization in human tissues. RESULTS: Resting human CD8 and CD4 T cells expressed the CXCR4, but not the CXCR7, receptor for CXCL12. Treatment with CXCL12 induced expression of both iNOS mRNA and protein in primary human CD8 T cells in a dose-dependent manner, but had no effect on CD4 T cells. Induction of iNOS expression in CD8 T cells was mediated by increased gene transcription. T-cell-receptor (TCR)-activated CD8 T cells rapidly downregulated CXCR4, which coincided with diminished ability of CXCL12 to induce iNOS in activated T cells. iNOS expression in infiltrating human CD8 T cells was spatially associated with CXCL12 expression both in the humanized mouse model of allograft artery rejection and in clinical specimens of coronary arteries displaying allograft vasculopathy. CONCLUSIONS: CXCL12 induces iNOS expression in human CD8 T cells and this response may contribute to allograft rejection.


Assuntos
Linfócitos T CD8-Positivos/enzimologia , Quimiocina CXCL12/farmacologia , Rejeição de Enxerto/patologia , Óxido Nítrico Sintase Tipo II/genética , Animais , Artérias/imunologia , Artérias/patologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/enzimologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Células Cultivadas , Quimiocina CXCL12/fisiologia , Vasos Coronários/enzimologia , Modelos Animais de Doenças , Citometria de Fluxo , Genes Reporter , Transplante de Coração/patologia , Humanos , Camundongos , Camundongos Endogâmicos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Homólogo
20.
J Biol Chem ; 283(11): 6832-42, 2008 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-18192275

RESUMO

Interferon (IFN)-gamma actions on the vessel wall play an important role in the pathogenesis of arteriosclerosis, yet the contribution of different IFN-gamma signaling pathways to the phenotypic modulation of vascular smooth muscle cells (VSMCs) are poorly understood. We investigated the effects of IFN-gamma on VSMCs and arteries through interactions involving signal transducer and activator of transcription (STAT) proteins. In addition to STAT1 activation, IFN-gamma consistently phosphorylated STAT3 in human VSMCs but weakly or not at all in human endothelial cells or mouse VSMCs. STAT3 activation resulted in nuclear translocation of this transcription factor. By selectively inhibiting STAT3 and not STAT1 signaling, we identified a number of candidate IFN-gamma-inducible, STAT3-dependent gene products by microarray analysis. Results for selected genes, including the pro-apoptotic molecules X-linked inhibitor of apoptosis associated factor-1 (XAF1) and Noxa, were verified by real time quantitative reverse transcription-PCR and immunoblot analyses. IFN-gamma-induced STAT3 and STAT1 signaling in VSMCs demonstrated reciprocal inhibition. STAT3 activation by IFN-gamma sensitized VSMCs to apoptosis triggered by both death receptor- and mitochondrial-mediated pathways. Knock down of XAF1 and Noxa expression inhibited the priming of VSMCs to apoptotic stimuli by IFN-gamma. Finally, we confirmed the in vivo relevance of our observations using a chimeric animal model of immunodeficient mice bearing human coronary artery grafts in which the expression of XAF1 and Noxa as well as the pro-apoptotic effects induced by IFN-gamma were dependent on STAT3. The data suggest STAT1-independent signaling by IFN-gamma via STAT3 that promotes the death of human VSMCs.


Assuntos
Proteínas F-Box/metabolismo , Regulação da Expressão Gênica , Interferon gama/fisiologia , Músculo Liso Vascular/patologia , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fator de Transcrição STAT3/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Apoptose , Proteínas Reguladoras de Apoptose , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Modelos Biológicos , Transdução de Sinais , Transplante de Tecidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...