IL-23-independent induction of IL-17 from γδT cells and innate lymphoid cells promotes experimental intraocular neovascularization.

Choroidal neovascularization (CNV) is a characteristic of age-related macular degeneration. Genome-wide association studies have provided evidence that the immune system is involved in the pathogenesis of age-related macular degeneration; however, the role of inflammatory cytokines in CNV has not been established. In this study, we demonstrated that IL-17 had a strong potential for promoting neovascularization in a vascular endothelial growth factor-independent manner in laser-induced experimental CNV in mice. Infiltrated γδT cells and Thy-1(+) innate lymphoid cells, but not Th17 cells, were the main sources of IL-17 in injured eyes. IL-23 was dispensable for IL-17 induction in the eye. Instead, we found that IL-1ß and high-mobility group box 1 strongly promoted IL-17 expression by γδT cells. Suppression of IL-1ß and high-mobility group box 1, as well as depletion of γδT cells, reduced IL-17 levels and ameliorated experimental CNV. Our findings suggest the existence of a novel inflammatory cytokine network that promotes neovascularization in the eye.

EBI3 is pivotal for the initiation of experimental autoimmune uveitis.

Murine experimental autoimmune uveitis (EAU) is a model for human autoimmune uveitis, whose pathogenesis is caused by both Th1 and Th17 cell responses. Epstein-Barr virus-induced gene 3 (EBI3) is a component of the heterodimeric cytokines: interleukin (IL)-27 and IL-35. Although IL-27 was shown to initiate Th1 cell development, it is also recognized as a negative regulator of fully activated CD4+ T cells, including Th17 cells. Recently, IL-35 also has also been reported to play immunosuppressive roles in autoimmunity. To investigate the roles of EBI3 in EAU, EBI3(-/-) mice were immunized with human interphotoreceptor retinoid binding protein peptide 1-20 (IRBP) to induce EAU. We observed that the clinical score in EBI3(-/-) mice was diminished compared with that in EBI3(+/+) mice up to day 22 after immunization, whereas the score in EBI3(-/-) mice reached the same levels as that of EBI3(+/+) mice after day 28. Histological analysis revealed a significant reduction of cellular infiltration into the retina in EBI3(-/-) mice on day 16. Although Th1 cell responses and IRBP-specific IL-10 production were reduced in EBI3(-/-) mice, the development of Th17 cell responses was unaffected on day 9. On day 21, Th1 cell responses and IRBP-specific IL-10 production was restored to the same levels as that in EBI3(+/+) mice, and Th17 cell responses significantly increased in EBI3(-/-) mice. Furthermore, Foxp3 expression in CD4+ T cells was comparable between EBI3(+/+) and EBI3(-/-) mice on days 9 and 21. Therefore, these results indicate that EBI3 may be important in EAU initiation by Th1 cell responses and may suppress EAU by inhibition of both Th1 and Th17 cell responses in the late/maintenance phase.

[A case report of malignant lymphoma receiving infliximab therapy with Behçet's disease].

BACKGROUND: To report a case of malignant lymphoma occurring in Behçet's disease (BD) with infliximab therapy. CASE: A 62-year-old man was diagnosed with BD in 1997. Despite treatment with colchicine, cyclosporine and prednisolone, he had frequent bilateral posterior ocular attacks. He was started on infliximab in August 2007 and for 6 months had no ocular attacks. Cyclosporine was therefore reduced. After 4 years of infliximab administration, he had neither ocular attacks nor general symptoms. However, he had general malaise and weight loss from the end of March 2012. Peripheral blood examination showed abnormal cells, so we terminated the infliximab. Bone marrow aspiration showed diffuse proliferation of medium to large lymphoid cells, and the histological diagnosis was diffuse large B-cell lymphoma. He was treated with 8 cycles of chemotherapy and 4 times intrathecal chemotherapy, and is now in remission. After termination of infliximab, he had no further ocular attacks. CONCLUSION: Although malignant lymphoma associated with BD is rare, attending ophthalmologists need to keep it in mind.

Loss of SOCS3 in T helper cells resulted in reduced immune responses and hyperproduction of interleukin 10 and transforming growth factor-beta 1.

Suppressor of cytokine signaling (SOCS)3 is a major negative feedback regulator of signal transducer and activator of transcription (STAT)3-activating cytokines. Transgenic mouse studies indicate that high levels of SOCS3 in T cells result in type 2 T helper cell (Th2) skewing and lead to hypersensitivity to allergic diseases. To define the physiological roles of SOCS3 in T cells, we generated T cell-specific SOCS3 conditional knockout mice. We found that the mice lacking SOCS3 in T cells showed reduced immune responses not only to ovalbumin-induced airway hyperresponsiveness but also to Leishmania major infection. In vitro, SOCS3-deficient CD4+ T cells produced more transforming growth factor (TGF)-beta1 and interleukin (IL)-10, but less IL-4 than control T cells, suggesting preferential Th3-like differentiation. We found that STAT3 positively regulates TGF-beta1 promoter activity depending on the potential STAT3 binding sites. Furthermore, chromatin immunoprecipitation assay revealed that more STAT3 was recruited to the TGF-beta1 promoter in SOCS3-deficient T cells than in control T cells. The activated STAT3 enhanced TGF-beta1 and IL-10 expression in T cells, whereas the dominant-negative form of STAT3 suppressed these. From these findings, we propose that SOCS3 regulates the production of the immunoregulatory cytokines TGF-beta1 and IL-10 through modulating STAT3 activation.

Sjögren's syndrome-like ocular surface disease in thrombospondin-1 deficient mice.

Thrombospondin-1 (TSP-1) is a major activator of latent transforming growth factor-beta in vitro as well as in vivo. Mice deficient in TSP-1, despite appearing normal at birth, develop a chronic form of ocular surface disease that is marked by increased apoptosis and deterioration in the lacrimal gland, associated dysfunction, and development of inflammatory infiltrates that result in abnormal tears. The increase in CD4(+) T cells in the inflammatory infiltrates of the lacrimal gland, and the presence of anti-Sjögren's syndrome antigen A and anti-Sjögren's syndrome antigen B antibodies in the serum resemble autoimmune Sjögren's syndrome. These mice develop an ocular surface disorder dry eye that includes disruption of the corneal epithelial layer, corneal edema, and a significant decline in conjuctival goblet cells. Externally, several mice develop dry crusty eyes that eventually close. The inflammatory CD4(+) T cells detected in the lacrimal gland, as well as those in the periphery of older TSP-1 null mice, secrete interleukin-17A, a cytokine associated with chronic inflammatory diseases. Antigen-presenting cells, derived from TSP-1 null, but not from wild-type mice, activate T cells to promote the Th17 response. Together, these results indicate that TSP-1 deficiency results in a spontaneous form of chronic dry eye and aberrant histopathology associated with Sjögren's syndrome.

Increased IkappaB alpha expression is essential for the tolerogenic property of TGF-beta-exposed APCs.

IkappaB alpha is an inhibitor of the transcriptional factor NF-kappaB, and it is an essential component of the signaling pathways that lead to expression of inflammatory molecules. These include cytokines and costimulatory molecules associated with antigen presentation in an inflammatory immune response. In this study, we report that antigen-presenting cells exposed to TGF-beta induce peripheral tolerance by increasing IkappaB alpha expression. Exposure of antigen presenting cells (APCs) to TGF-beta is known to impair their ability to secrete IL-12, and such impairment correlated with reduced NF-kappaB activity as indicated by significantly reduced nuclear levels of p50, an essential subunit of NF-kappaB for IL-12 transcription. Blockade of increased nuclear IkappaB alpha in APCs by expression of small interfering RNA molecules (siRNAs) targeting IkappaB alpha transcripts prevented IL-12 impairment and the decline in nuclear p50 levels. Furthermore, such IkappaB alpha blockade also interfered with the tolerogenic property of TGF-beta-exposed APCs. However, increased expression of IkappaB alpha in APCs, independent of TGF-beta exposure, reduced nuclear p50 levels and permitted tolerance induction by APCs. Thus, our findings attribute a direct and significant role to IkappaB alpha in the tolerogenic potential of APCs. Increased IkappaB alpha expression in APCs may therefore offer a therapeutic approach to achieve antigen-specific immunomodulation.

Involvement of Th17 cells and the effect of anti-IL-6 therapy in autoimmune uveitis.

OBJECTIVES: Human endogenous uveitis is one of the sight-threatening diseases associated with variety of systemic disorders, such as Behcet's disease and sarcoidosis. Recently, biosynthesized antibodies against inflammatory cytokines have been recognized to be useful to control the regional inflammation. In this study, we focused on the possibility of IL-6-based biological therapies for endogenous uveitis. We initially confirmed the significant increase of several inflammatory soluble factors including IL-6 in the vitreous fluids from refractory/chronic engogenous uveitis patients. METHODS: To investigate the role of IL-6 in the formation of refractory ocular inflammation, we used the mouse experimental autoimmune uveitis (EAU) model. Both IL-6 and IL-23 are required for the development of IL-17-producing helper T subset (Th17) from naïve CD4(+) T cells. Results. In the EAU model, neither IL-6-deficient mice nor IL-23-deficient mice could induce Th17 cells and the EAU score was decreased in these mice in the entire time course. We also confirmed that systemic administration of anti-il-6 receptor antibody ameliorates EAU By suppressing both systemic and regional TH17 responses. CONCLUSIONS: IL-6 is responsible for causing ocular inflammation, and it is, at least partially, due to IL-6-dependent Th17 differentiation. IL-6 may be a target for therapy of refractory endogenous uveitis in humans.

Differential roles for IFN-gamma and IL-17 in experimental autoimmune uveoretinitis.

IL-17-producing CD4(+) T cells, so called T(h)17 cells, constitute a newly identified inflammatogenic cell population, which is critically involved in some inflammatory diseases. To explore the role of T(h)17 cells in murine experimental autoimmune uveoretinitis (EAU), a model of human autoimmune uveitis where T(h)1 responses predominantly participate in the pathogenesis, IL-17(-/-) mice were immunized with interphotoreceptor retinoid-binding protein peptide 1-20 for disease induction. Funduscopic examination revealed that EAU was induced in IL-17(-/-) mice just like in wild-type (WT) mice at early phases of the disease. However, at later/maintenance phases, the severity was significantly reduced in IL-17(-/-) mice. Expression of IFN-gamma and MCP-1 was comparable between WT and IL-17(-/-) mice during the time course. In vivo blockade of IFN-gamma and IL-4 resulted in exacerbation of EAU at later phases with augmented IL-17 production. Taken together, our data demonstrated that IL-17/T(h)17 participates in the late phases of EAU and also that T(h)1 and T(h)17 responses are differentially required for EAU.

Interleukin-18 regulates pathological intraocular neovascularization.

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.

Crucial role of P2X7 receptor for effector T cell activation in experimental autoimmune uveitis.

PURPOSE: To investigate the roles of P2X7 receptors (P2RX7) in the pathogenesis of experimental autoimmune uveoretinitis (EAU). STUDY DESIGN: Experimental. METHODS: Either wild-type (P2rx7 +/+ ) or P2rx7-deficient (P2rx7 -∕- ) mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) peptide 1-20. Severity of EAU was evaluated clinically and histopathologically. The induction of IRBP-specific proliferation and cytokines in draining lymph nodes was assessed by enzyme-linked immunosorbent assays (ELISA). The frequency of activation markers was examined by flow cytometry. Furthermore, inhibitory roles of systemic administration of Brilliant Blue G (BBG), an antagonist for P2RX7, in EAU were also assessed in the wild-type mice. RESULTS: The severity of EAU in P2rx7 -∕- mice was reduced as compared with that in P2rx7 +/+ mice, both clinically and histopathologically. IRBP-specific proliferation in P2rx7 -∕- on day 16 was slightly decreased compared to that in P2rx7 +/+ mice. The induction of IRBP-specific interferon (IFN)-γ and interleukin (IL)-17 in P2rx7 -∕- mice on day 16 was lower than that in P2rx7 +/+ mice. The up-regulation of surface expression of activation markers such as CD25, CD44, and CD69 in response to TCR stimulation in P2rx7 -∕- mice was decreased as compared with that in P2rx7 +/+ mice. Furthermore, neutralization of P2RX7 in vivo by BBG suppressed EAU clinically and histopathologically. IRBP-specific IFN-γ and IL-17 induction in BBG-treated mice was significantly lower than that in vehicle-treated mice. CONCLUSION: The results suggest that P2RX7 is a novel preventative therapeutic target for uveitis as it suppresses the effector functions of both Th1 and Th17 cell responses.

Different distributions of M1 and M2 macrophages in a mouse model of laser-induced choroidal neovascularization.

Choroidal neovascularization (CNV) is a serious complication of age­related macular degeneration. The aim of the present study was to investigate the expression and distribution of M1 and M2 macrophages in a laser­induced CNV adult mouse model. The mRNA expression levels of M1, M2 and pan macrophage markers, and macrophage­associated angiogenic cytokines, were determined by reverse transcription­quantitative polymerase chain reaction. Immunofluorescence studies were performed to determine the location of the macrophages. The expression levels of M1 macrophage markers increased to a greater extent compared with M2 markers in the retinal pigment epithelium (RPE)­choroid complexes following laser photocoagulation. By contrast, the expression levels of M2 macrophage markers increased primarily in the retinas. Immunofluorescence studies revealed that the increased number of cluster of differentiation (CD)206­positive cells were located primarily in the retina, whereas the CD80­positive cells were located around the site of CNVs in the RPE­choroid. In addition, the M1­associated cytokines increased to a greater extent in the RPE­choroid complexes, whereas the M2­associated cytokines were highly expressed in the retinas. These findings indicate that M1 and M2 macrophage numbers increased following CNV; however, the locations were different in this mouse model of laser­induced CNV. The results of the present study suggest that M1 macrophages have a more direct role in inhibiting the development of CNV.

Gene Expression Analysis of the Irrigation Solution Samples Collected during Vitrectomy for Idiopathic Epiretinal Membrane.

PURPOSE: The analysis of gene expression in idiopathic epiretinal membranes (iERMs) may help elucidate ERM formation and its pathology. Here, we conducted a case-control study, in order to determine the expression levels of cytokines and other genes in eyes with macular hole (MH) or iERM. METHODS: Twenty eyes, obtained from seven male and 13 female patients, were included in the study. The average age of the study subjects was 69.1 ± 7.67 years, and 15 eyes had iERM, while five eyes had MH. Irrigation solution samples were collected during vitrectomy, centrifuged, and the levels of cytokine and other mRNAs in the sediment were assessed using real-time PCR. The expression level of 11 cytokine genes, four transcription factor genes, two cytoskeletal genes, and genes encoding two extracellular matrix proteins in eyes with MH or iERM were determined and compared. RESULTS: The expression levels of interleukin 6 (IL6), tumor growth factor B2 (TGFB2), vascular endothelial growth factor A (VEGFA), chemokine C-X-C motif ligand 1 (CXCL1), v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA), glial fibrillary acidic protein (GFAP), and tenascin C (TNC) were significantly higher in eyes with iERM than in eyes with MH. The expression of these genes was not associated with the preoperative visual acuity of the investigated patients. CONCLUSIONS: The obtained results indicate that real-time PCR analysis of irrigation solution samples collected during vitrectomy can help assess the expression levels of several genes, and that iERM is associated with the expression of pro-inflammatory genes and the genes expressed during angiogenesis and wound healing process (IL6, TGFB2, VEGFA, CXCL1, RELA, GFAP, and TNC).

M2 Macrophages Enhance Pathological Neovascularization in the Mouse Model of Oxygen-Induced Retinopathy.

PURPOSE: To investigate the roles played by M2 macrophages in a mouse model of oxygen-induced retinopathy (OIR). METHODS: Oxygen-induced retinopathy was induced in C57BL/6J mice by exposing postnatal day seven (P7) pups to 75% oxygen and then returning them to room air at P12. Real-time RT-PCR and immunofluorescence staining were used to assess the levels and distributions of different macrophage markers. Bone marrow-derived M1 and M2 macrophages and mannosylated clodronate liposomes (MCLs) were injected into the vitreous on P12 to examine the effects at P17. M2 macrophages were cocultured with human retinal endothelial cells (HRECs) to examine their effects on proliferation and tube formation. RESULTS: The results showed that the M2 macrophages, rather than M1 phenotype, were highly expressed in OIR mice. The number of M2 macrophages had increased significantly at P17, and the increase was closely associated with the presence of neovascular tufts in the OIR retinas. Selective depletion of M2 macrophages suppressed the pathological neovascularization and promoted physiological revascularization. In contrast, intravitreal injection of bone marrow-derived M2 macrophages or the culture supernatants promoted pathological neovascularization and inhibited physiological revascularization. In an in vitro coculture system, M2-polarized macrophages significantly promoted proliferation and tube formation of HRECs. CONCLUSIONS: These results indicated that M2 macrophages, rather than M1, play an important role in promoting retinal pathological neovascularization probably by producing secreted factors. Thus, targeting M2 macrophages could be a potential therapeutic option for inhibiting retinal pathological neovascularization.

Dietary Omega-3 Fatty Acids Suppress Experimental Autoimmune Uveitis in Association with Inhibition of Th1 and Th17 Cell Function.

Omega (ω)-3 long-chain polyunsaturated fatty acids (LCPUFAs) inhibit the production of inflammatory mediators and thereby contribute to the regulation of inflammation. Experimental autoimmune uveitis (EAU) is a well-established animal model of autoimmune retinal inflammation. To investigate the potential effects of dietary intake of ω-3 LCPUFAs on uveitis, we examined the anti-inflammatory properties of these molecules in comparison with ω-6 LCPUFAs in a mouse EAU model. C57BL/6 mice were fed a diet containing ω-3 LCPUFAs or ω-6 LCPUFAs for 2 weeks before as well as after the induction of EAU by subcutaneous injection of a fragment of human interphotoreceptor retinoid-binding protein emulsified with complete Freund's adjuvant. Both clinical and histological scores for uveitis were smaller for mice fed ω-3 LCPUFAs than for those fed ω-6 LCPUFAs. The concentrations of the T helper 1 (Th1) cytokine interferon-γ and the Th17 cytokine interleukin-17 in intraocular fluid as well as the production of these cytokines by lymph node cells were reduced for mice fed ω-3 LCPUFAs. Furthermore, the amounts of mRNAs for the Th1- and Th17-related transcription factors T-bet and RORγt, respectively, were reduced both in the retina and in lymph node cells of mice fed ω-3 LCPUFAs. Our results thus show that a diet enriched in ω-3 LCPUFAs suppressed uveitis in mice in association with inhibition of Th1 and Th17 cell function.

[Pathophysiology and new treatment of uveitis].

Uveitis is narrow-defined inflammation of the uvea, also clinically include all inflammatory conditions in the eye. Uveitis may occur as a consequence of various causes and background, such as autoimmune diseases, infections, and hematopoietic malignancy. We have to treat uveitis not only controlling the inflammation but also maintaining up the visual function of the eye because the most uveitis is chronic and relapsing inflammatory disorder. Behçét's disease is a systemic disease and results in loss of vision without adequate treatment. Behçét's disease was a representative of vision loss uveitis because Behçét's patient usually had treatment resistance of conventional treatment, such as colchicine and cyclosporine. However, biological therapy with TNF-α, which started from 2007, has revolutionized the treatment strategy of Behçét's disease. It is not too much to say that Behçét's patient is free from fear of vision loss by the dramatic decrease of ocular attach. Biological therapy is not approved as a treatment of uveitis except Behçét's disease. Some protracted cases of Sarcoidosis and Vogt-Koyanagi-Harada disease are resistant to corticosteroid therapy and require new treatment. In this review, we discuss the pathophysiology of uveitis and report new treatment of Behçét's disease by biological therapy.

Melanocyte-secreted fibromodulin promotes an angiogenic microenvironment.

Studies have established that pigmentation can provide strong, protective effects against certain human diseases. For example, angiogenesis-dependent diseases such as wet age-related macular degeneration and infantile hemangioma are more common in light-skinned individuals of mixed European descent than in African-Americans. Here we found that melanocytes from light-skinned humans and albino mice secrete high levels of fibromodulin (FMOD), which we determined to be a potent angiogenic factor. FMOD treatment stimulated angiogenesis in numerous in vivo systems, including laser-induced choroidal neovascularization, growth factor-induced corneal neovascularization, wound healing, and Matrigel plug assays. Additionally, FMOD enhanced vascular sprouting during normal retinal development. Deletion of Fmod in albino mice resulted in a marked reduction in the amount of neovascularization induced by retinal vein occlusion, corneal growth factor pellets, and Matrigel plugs. Our data implicate the melanocyte-secreted factor FMOD as a key regulator of angiogenesis and suggest an underlying mechanism for epidemiological differences between light-skinned individuals of mixed European descent and African-Americans. Furthermore, inhibition of FMOD in humans has potential as a therapeutic strategy for treating angiogenesis-dependent diseases.

Suppression of autoimmune retinal inflammation by an antiangiogenic drug.

Chronic and recurrent uveitis account for approximately 10% of legal blindness in the western world. Autoimmune uveitis is driven by activated CD4(+) T cells that differentiate into effector T helper cells (Th1, Th2, and Th17) which release proinflammatory cytokines that damage the retina. In this study we investigated the effect of the methionine aminopeptidase 2 (MetAP2) inhibitor, Lodamin, on T cell activation and differentiation. MetAp2 is an enzyme which regulates cellular protein synthesis and is highly expressed in T cells. Lodamin was found to suppress T cell receptor (TCR) mediated T cell proliferation and reduced the production of Th1 and Th17 cells. Further, Lodamin suppressed overall inflammation in the mouse model of experimental autoimmune uveitis (EAU) by a six fold. This effect was attributed in part to a reduction in retinal proinflammatory cytokines, down regulation of MetAP2 expression in purified lymph node CD4(+) T cells, and a general normalization of the systemic immune reaction.

IL-10 is significantly involved in HSP70-regulation of experimental subretinal fibrosis.

Subretinal fibrosis is directly related to severe visual loss, especially if occurs in the macula, and is frequently observed in advanced age-related macular degeneration and other refractory eye disorders such as diabetic retinopathy and uveitis. In this study, we analyzed the immunosuppressive mechanism of subretinal fibrosis using the novel animal model recently demonstrated. Both TLR2 and TLR4 deficient mice showed significant enlargement of subretinal fibrotic area as compared with wild-type mice. A single intraocular administration of heat shock protein 70 (HSP70), which is an endogenous ligand for TLR2 and TLR4, inhibited subretinal fibrosis in wild-type mice but not in TLR2 and TLR4-deficient mice. Additionally, HSP70 induced IL-10 production in eyes from wild-type mice but was impaired in both TLR2- and TLR4-deficient mice, indicating that HSP70-TLR2/TLR4 axis plays an immunomodulatory role in subretinal fibrosis. Thus, these results suggest that HSP70-TLR2/TLR4 axis is a new therapeutic target for subretinal fibrosis due to prognostic CNV.

A Novel Platelet-Activating Factor Receptor Antagonist Inhibits Choroidal Neovascularization and Subretinal Fibrosis.

Choroidal neovascularization (CNV) is a critical pathogenesis in age-related macular degeneration (AMD), the most common cause of blindness in developed countries. To date, the precise molecular and cellular mechanisms underlying CNV have not been elucidated. Platelet-activating factor (PAF) has been previously implicated in angiogenesis; however, the roles of PAF and its receptor (PAF-R) in CNV have not been addressed. The present study reveals several important findings concerning the relationship of the PAF-R signaling with CNV. PAF-R was detected in a mouse model of laser-induced CNV and was upregulated during CNV development. Experimental CNV was suppressed by administering WEB2086, a novel PAF-R antagonist. WEB2086-dependent suppression of CNV occurred via the inhibition of macrophage infiltration and the expression of proangiogenic (vascular endothelial growth factor) and proinflammatory molecules (monocyte chemotactic protein-1 and IL-6) in the retinal pigment epithelium-choroid complex. Additionally, WEB2086-induced PAF-R blockage suppresses experimentally induced subretinal fibrosis, which resembles the fibrotic subretinal scarring observed in neovascular AMD. As optimal treatment modalities for neovascular AMD would target the multiple mechanisms of AMD-associated vision loss, including neovascularization, inflammation and fibrosis, our results suggest PAF-R as an attractive molecular target in the treatment of AMD.

Aminoimidazole carboxamide ribonucleotide ameliorates experimental autoimmune uveitis.

PURPOSE: To investigate the anti-inflammatory effect of an adenosine monophosphate (AMP) analog, aminoimidazole carboxamide ribonucleotide (AICAR), in experimental autoimmune uveoretinitis (EAU). METHODS: C57BL/6 mice were injected daily with AICAR (200 mg/kg, intraperitoneally [IP]) from day 0, the day of interphotoreceptor retinoid-binding protein (IRBP) immunization, until day 21. The severity of uveitis was assessed clinically and histopathologically. T-cell proliferation and cytokine production of IFN-γ, IL-17, and IL-10 in response to IRBP stimulation were determined. In addition, regulatory T-cell (Treg) populations were measured. Co-stimulatory molecule expression (CD40, 80, 86, and I-Ab) on dendritic cells (DCs) in EAU and on bone marrow-derived dendritic cells (BMDCs) treated with AICAR was measured. RESULTS: AICAR treatment significantly reduced clinical and histologic severity of EAU as well as ocular cytokine production. An anti-inflammatory effect associated with the inhibition of T-cell proliferation and Th1 and Th17 cytokine production was observed. Increases in the Th2 response and Treg population were not observed with AICAR treatment. AICAR did significantly inhibit BMDC maturation by reducing co-stimulatory molecule expression. CONCLUSIONS: AICAR attenuates EAU by preventing generation of Ag-specific Th1 and Th17 cells. Impaired DC maturation may be an underlying mechanism for this anti-inflammatory effect observed with AICAR.