RESUMEN
Choroidal neovascularization (CNV) is directly related to visual loss in age-related macular degeneration and other macular disorders. We have investigated the role of CD1d-restricted invariant natural killer T (NKT) cells in laser-induced experimental CNV. Quantitative real-time PCR detected increased expression of NKT cell-related genes (Valpha14 and CXCL16) in whole eyes undergoing CNV, indicating local accumulation of NKT cells. We found a significant reduction of CNV and lower concentrations of vascular endothelial growth factor (VEGF) in ocular fluid in two different NKT cell-deficient mice, CD1d knockout (KO) and Jalpha18 KO mice. We also established in vitro co-cultures of retinal pigment epithelial cells and splenic NKT cells, and confirmed NKT cells could produce VEGF in the dish. Moreover, inoculating alpha-galactosylceramide, the ligand for NKT cells, into the vitreous cavity of C57BL/6 mice promoted CNV. We concluded that NKT cells play an important role in CNV as an inducer of VEGF.
Asunto(s)
Antígenos CD1/fisiología , Neovascularización Coroidal/inmunología , Células Asesinas Naturales/inmunología , Linfocitos T/inmunología , Animales , Anticuerpos/inmunología , Antígenos CD1/genética , Antígenos CD1d , Quimiocina CXCL16 , Quimiocina CXCL6/genética , Neovascularización Coroidal/inducido químicamente , Neovascularización Coroidal/genética , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Células Epiteliales/citología , Femenino , Galactosilceramidas/toxicidad , Genes Codificadores de la Cadena alfa de los Receptores de Linfocito T , Interleucina-6/genética , Interleucina-6/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Epitelio Pigmentado Ocular/citología , Bazo/citología , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Recently, the proinflammatory cytokine IL-18 has been shown to have a role in angiogenesis. This study aimed to elucidate its role in abnormal neovascularization (NV) in an oxygen-induced retinopathy (OIR) mouse model of the retinopathy seen in human premature newborns. IL-18 was constitutively expressed in the retina in C57BL/6 mice, but expression transiently dropped on Day 17 after birth in mice exposed to 75% oxygen for 5 days between Days 7 and 12. Coincident with the IL-18 reduction in oxygen-treated mice, vascular endothelial growth factor was expressed in the retina, and OIR developed. By Day 24, NV in the retina had regressed to normal levels. By contrast, IL-18 knockout mice, exposed to elevated oxygen concentrations, developed more severe OIR on Day 17, and it is important that this persisted until Day 24. This suggested that IL-18 negatively regulated retinal NV. To investigate this further, we administrated recombinant IL-18 to C57BL/6 mice during the development of OIR but found no significant inhibition of retinopathy. However, when IL-18-binding protein was administered during the OIR recovery phase to neutralize endogenous IL-18, OIR was still apparent on Day 24. We therefore concluded that IL-18 regulates pathogenic retinal NV by promoting its regression rather than inhibiting its development. This suggests some useful, new approaches to treating retinopathy in humans.
Asunto(s)
Regulación de la Expresión Génica , Interleucina-18/metabolismo , Oxígeno/farmacología , Retina/metabolismo , Neovascularización Retiniana/metabolismo , Animales , Citocinas/metabolismo , Modelos Animales de Enfermedad , Péptidos y Proteínas de Señalización Intercelular/farmacología , Interferón gamma/metabolismo , Interleucina-18/genética , Interleucina-18/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neovascularización Retiniana/inducido químicamente , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Inflammatory angiogenesis is a critical process in tumor progression and other diseases. The inflammatory cytokine IL-1beta promotes angiogenesis, tumor growth, and metastasis, but its mechanisms remain unclear. We examined the association between IL-1beta-induced angiogenesis and cell inflammation. IL-1beta induced neovascularization in the mouse cornea at rates comparable to those of VEGF. Neutrophil infiltration occurred on day 2. Macrophage infiltration occurred on days 4 and 6. The anti-Gr-1 Ab-induced depletion of infiltrating neutrophils did not affect IL-1beta- or VEGF-induced angiogenesis. The former was reduced in monocyte chemoattractant protein-1-deficient (MCP-1(-/-)) mice compared with wild-type mice. After day 4, clodronate liposomes, which kill macrophages, reduced IL-1beta-induced angiogenesis and partially inhibited VEGF-induced angiogenesis. Infiltrating macrophages near the IL-1beta-induced neovasculature were COX-2 positive. Lewis lung carcinoma cells expressing IL-1beta (LLC/IL-1beta) developed neovasculature with macrophage infiltration and enhanced tumor growth in wild-type but not MCP-1(-/-) mice. A COX-2 inhibitor reduced tumor growth, angiogenesis, and macrophage infiltration in LLC/IL-1beta. Thus, macrophage involvement might be a prerequisite for IL-1beta-induced neovascularization and tumor progression.
Asunto(s)
Movimiento Celular , Ciclooxigenasa 2/genética , Interleucina-1/fisiología , Macrófagos/enzimología , Macrófagos/patología , Neoplasias/enzimología , Neoplasias/patología , Neovascularización Patológica/metabolismo , Animales , Movimiento Celular/fisiología , Quimiocina CCL2/deficiencia , Quimiocina CCL2/genética , Córnea/patología , Ciclooxigenasa 2/biosíntesis , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Factor A de Crecimiento Endotelial Vascular/fisiologíaRESUMEN
The immune privilege that exists in the eye is maintained by various mechanisms. One of the best studied is a form of systemic tolerance termed anterior chamber-associated immune deviation (ACAID). We have investigated the mechanisms by which ocular inflammation associated with the vitreous cavity (VC) is reduced, by injecting either ovalbumin (OVA) or allogeneic splenocytes into the VCs of mice, and assessed the effect of this on delayed type hypersensitivity (DTH) responses. After antigen inoculation into the VC, antigen-specific DTH responses were significantly impaired and we named this phenomenon 'vitreous cavity-associated immune deviation' (VCAID). VCAID could also be induced by inoculating antigen-pulsed macrophages into the VC. However, VCAID did not develop either in mice with inflamed eyes, whether as a result of experimental autoimmune uveitis or coadministration of interleukin (IL)-6 in the VC, or in knockout mice deficient for natural killer T (NKT) cells. Finally, we found that so-called 'hyalocytes' are the only cells present in the VCs of normal mice, uniformly distributed on the retinal surface. Interestingly, they express F4/80, suggesting that hyalocytes are candidate antigen-presenting cells (APCs) responsible for mediating VCAID. As for the anterior chamber model, systemic tolerance can be induced in the VC in non-inflamed eyes and in the presence of invariant NKT cells.