RESUMEN
4-1BB, a member of the tumor necrosis factor receptor (TNFR) family, binds the 4-1BB ligand (4-1BBL), works as a costimulatory molecule, and regulates T cell-mediated immune responses. Although inflammation is an essential pathological feature of myocarditis, the role of 4-1BB in experimental autoimmune myocarditis (EAM) remains unclear. Lewis rats were immunized on day 0 with purified porcine cardiac myosin to establish EAM. 4-1BB-immunoglobulin (4-1BBIg) was administered intraperitoneally (n=6) a total of 9 times (3 times per week). Rats were killed on day 21 to study effects of 4-1BB/4-1BBL pathway blockade. For controls, isotype-matched human IgG was administered in other EAM rats (n=6). Histologic and echocardiographic examination showed development of EAM attenuated by 4-1BBIg. Suppression of mRNA expression for IL-1alpha, IL-1beta, IL-4, IL-6, and TNF-alpha was noted in the heart tissue treated with 4-1BBIg. Treatment with 4-1BBIg reduced production of Th1-type cytokines, and inhibited T cell proliferation in vitro. In the 4-1BB signaling pathway in splenocytes, 4-1BBIg suppressed JNK, p38, and IkappaB activity but not that of ERK1/2. Blockade of T cell activation through the 4-1BB/4-1BBL pathway regulates development of EAM; therefore, 4-1BB may be an effective target for treating myocarditis.
Asunto(s)
Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/prevención & control , Activación de Linfocitos/inmunología , Miocarditis/inmunología , Miocarditis/prevención & control , Linfocitos T/inmunología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Ligando 4-1BB/metabolismo , Ligando 4-1BB/farmacología , Animales , Enfermedades Autoinmunes/enzimología , Enfermedades Autoinmunes/patología , Proliferación Celular/efectos de los fármacos , Citocinas/genética , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Quinasa I-kappa B/metabolismo , Inmunohistoquímica , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Activación de Linfocitos/efectos de los fármacos , Masculino , Miocarditis/enzimología , Miocarditis/patología , Miocardio/enzimología , Miocardio/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas Lew , Sus scrofa , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Células TH1/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
4-1BB, a member of the tumor necrosis factor (TNF) receptor superfamily, binds the 4-1BB ligand (4-1BBL) and works as a costimulatory molecule and regulates T cell-mediated immune responses. Because T cell-mediated immunity is associated with graft arterial disease (GAD), we investigated the role of the 4-1BB pathway in the progression of GAD. Hearts from C57BL/6 mice were transplanted into Bm12 mice (class II mismatch). 4-1BB expression was induced on CD4(+) and CD8(+) splenocytes in allografts after cardiac transplantation. 4-1BBL was detected in the vessel wall of the rejecting cardiac allograft and in cultured smooth muscle cells (SMCs) stimulated with fetal calf serum. Recipients were injected intraperitoneally with 4-1BBIg every 7 days for 8 weeks. GAD was significantly attenuated by 4-1BBIg treatment (luminal occlusion, 15.4 +/- 3.1% versus control IgG treatment, 75.6 +/- 4.6%, P < 0.001). T-cell infiltration of cardiac allografts and expression of interferon-g , interleukin-6, and interleukin-15 in cardiac allografts were suppressed by 4-1BBIg treatment. Coculture of SMCs with sensitized splenocytes after transplantation induced SMC proliferation, and this was inhibited by addition of 4-1BBIg. The 4-1BB pathway regulates not only T-cell activation but also SMC proliferation. Blockade of the 4-1BB pathway is a promising strategy to prevent progression of GAD.
Asunto(s)
Enfermedad Injerto contra Huésped/prevención & control , Trasplante de Corazón , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/fisiología , Ligando 4-1BB/metabolismo , Animales , Células Cultivadas , Inmunohistoquímica , Técnicas In Vitro , Interferón gamma/análisis , Interleucina-15/análisis , Interleucina-6/análisis , Prueba de Cultivo Mixto de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Liso/citología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Linfocitos T/inmunología , Trasplante Homólogo , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunologíaRESUMEN
Chemokines play an important role in induction of chemotaxis of immune cells. CCR1 is a chemokine receptor expressed on neutrophils, monocytes, and T lymphocytes. The role of CCR1 in immunity is not well examined. We demonstrated the role of CCR1 on T lymphocytes and the effect of a CCR1 antagonist, BX471 in myocarditis. Lewis rats were immunized with cardiac myosin on day 0 to establish experimental autoimmune myocarditis. Rats were then administered BX471 subcutaneously every day (group BX0: n = 7) or from day 14 (group BX14: n = 7) and were killed on day 21. We confirmed expression of CCR1 in cells infiltrating the myocardium by immunohistochemistry and FACS analysis. The development of myocarditis was almost completely prevented in group BX0, and myocarditis-affected areas were significantly decreased in size in group BX14. Cardiac function was markedly improved. Ribonuclease protection assay showed that the CCR1 antagonist treatment suppressed mRNA expression for IL-6, IL-1beta, and TNF-alpha in the hearts. An antigen-specific T cell proliferation assay was performed with CD4-positive T cells isolated from control rats immunized with cardiac myosin. T cell proliferation was inhibited by the CCR1 antagonist. Additionally, we showed by Western blot that the CCR1 antagonist suppressed ERK1/2 and JNK activities in T cells stimulated with myosin and that IL-2 reversed this suppression. The CCR1 antagonist reduced the severity of EAM by inhibiting cytokine expression and inducing T cell inactivation. Thus, the CCR1 antagonist may provide a novel therapeutic strategy treatment of myocarditis.