Role of PU.1 Expression as an Inflammatory Marker in Experimental Autoimmune Uveoretinitis.

PURPOSE: PU.1 is an Ets family transcription factor, which is essential for the development of immune system through generation of myeloid and lymphoid lineages. In this study, we investigated PU.1 expression in the retina of mice with experimental autoimmune uveoretinitis (EAU) and the association between PU.1 expression level and inflammation in EAU. METHODS: IRBP 1-20 peptide-immunized mice were used. Quantitative PCR, ELISA analysis, cytometric bead array (CBA), assay and immunostaining were conducted using ocular tissues and lymph nodes. RESULTS: Quantitative PCR showed significant increases in mRNA levels of PU.1 in the retina at the peak of inflammation. Immunostaining of retina flat mounts revealed that most PU.1-positive cells were co-stained with anti-CD11c and anti-F4/80 antibodies. PU.1 knockdown in lymph node cells significantly suppressed IRBP-stimulated IFN-γ production measured by ELISA and IL-2 production measured by CBA. CONCLUSION: PU.1 may play crucial roles in the development and progression of inflammation in EAU.

Clinical Profile of Anti-Myelin Oligodendrocyte Glycoprotein Antibody Seropositive Cases of Optic Neuritis.

We have studied the clinical picture of anti-aquaporin antibody (AQP4-Ab)- and anti-myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-positive optic neuritis. However, optic neuritis associated with MOG-Abs has not been elucidated using new methods such as cell-based assay. Hence, we conducted a comprehensive investigation on its clinical profile. Serum samples from 70 patients (17 males and 53 females, mean age 43.1 years) with optic neuritis were tested for MOG-Abs by cell-based assay. In MOG-Ab seropositive patients, the disease type, recurrence status, and visual function outcome were analysed. Among 70 patients, 18 were MOG-Ab seropositive. The 18 patients comprised 2 with chronic relapsing inflammatory optic neuropathy, 2 with AQP4-Ab seropositive optic neuritis (neuromyelitis optica), 12 with idiopathic optic neuritis, and 2 with optic neuritis associated with multiple sclerosis. Excluding two cases that were also AQP4-Ab seropositive, MOG-Ab seropositive cases had relatively favourable visual acuity outcome (although not significantly different from seronegative cases) but had significant residual visual field deficit (p = 0.0015). Furthermore, the number of relapses of optic neuritis per year was significantly greater in MOG-Ab seropositive cases than in seronegative cases (0.82 vs. 0.40; p = 0.0005). MOG-Abs may contribute to the heterogeneous clinical picture of optic neuritis, and although visual acuity outcome is favourable, there is a tendency of residual visual field deficit and a possibility of repeated relapses.

Peroxisome proliferator-activated receptor-γ agonist pioglitazone suppresses experimental autoimmune uveitis.

Peroxisome proliferator-activated receptor (PPAR)-γ agonists are clinically used as anti-diabetes agents. Recent research has discovered that an anti-inflammatory effect of PPAR agonist may have the potential to treat autoimmune disease. In the present study, we investigated the anti-inflammatory effects of PPAR-γ agonist, pioglitazone, on murine model of endogenous uveitis. Experimental autoimmune uveoretinitis (EAU) was induced by immunizing C57BL/6 mice with human interphotoreceptor retinoid binding protein-derived peptide (1-20). Pioglitazone or vehicle was injected intravenously from day -1 (whole phase treatment) or day 8 (effector phase study) until day 20. Severity of EAU was assessed clinically and pathologically on day 21. Immunological status was assessed by measuring intraocular inflammatory factors, and activation and regulatory markers of CD4(+) T cells in draining lymph nodes (LNs). Treatment with pioglitazone suppressed both whole-phase and effector-phase of EAU. In effector-phase treatment, intraocular concentrations of TNF-α and IL-6 were significantly suppressed, and CD4(+)Foxp3(+) regulatory T cells and CD4(+)CD62L(high) naïve T cells increased in draining LNs, although there were no differences in CD4(+)CD44(high) effector T cells and IL-17 producing CD4(+) T cells between pioglitazone- and vehicle-treated mice. Administration of pioglitazone before and after the onset of EAU significantly reduced disease severity. The present results suggest that pioglitazone may be a novel therapeutic agent for endogenous uveitis.

Suppression of experimental autoimmune optic neuritis by the novel agent fingolimod.

PURPOSE: Fingolimod is an immunomodulating agent that has been approved for the treatment of multiple sclerosis. Fingolimod-phosphate is an antagonist of sphingosine-1-phosphate receptor and known to act by preventing infiltration of autoreactive lymphocytes into the central nervous system. In this study, we investigated whether fingolimod prevents experimental autoimmune optic neuritis (EAON). METHODS: EAON was induced by immunizing C57BL/6 mice with myelin oligodendrocyte glycoprotein-derived peptide 35-55 (MOG-p). After MOG-p immunization, fingolimod was administered intragastrically from day 1 (entire phase study) or from day 9 (effector phase study) until day 35. Visual acuity of the mice was measured using OptoMotry on days 7, 14, 21, 28, and 35 after immunization. On day 35 after immunization, the mice were killed and eyes and entire length of the optic nerves were submitted for histopathologic evaluation. RESULTS: In the positive control group, visual acuity decreased markedly from approximately day 14 after immunization, reaching a nadir on day 21. In the fingolimod-treated groups in both entire phase and effector phase studies, there was only minimal decline in visual acuity on day 14 after immunization, and mild deterioration on day 21, followed by recovery. Histopathologic study showed that fingolimod given throughout the entire phase or only from the effector phase suppressed murine EAON. Immunohistochemical study for neurofilament demonstrated no irregularity of the linear structure of the optic nerve in the fingolimod-treated mice compared with the positive control group. CONCLUSION: Fingolimod ameliorated EAON even when started after optic neuritis had developed. Further study is warranted to examine whether these findings are applicable to human disease.

Interleukin-10 gene-transfected mature dendritic cells suppress murine experimental autoimmune optic neuritis.

PURPOSE: We have reported that calcitonin gene-related peptide gene-transfected mature dendritic cells (mDC) suppress murine experimental autoimmune optic neuritis (EAON) and experimental autoimmune encephalitis (EAE) via interleukin-10 (IL-10) production. In our study, we examined whether IL-10-transfected mDC prevent development of EAON and EAE. METHODS: A plasmid expressing mouse IL-10 was constructed and used to transfect C57BL/6 mouse bone marrow-derived mDC by electroporation methods. C57BL/6 mice (with or without GFP expression) were immunized with myelo-oligodendrocyte glycoprotein35₋55 (MOG35₋55), and injected intravenously with IL-10-transfected mDC either in the induction or effector phase. RESULTS: When IL-10-transfected mDC were injected in the induction phase, EAE developed clinically in 60% of mice in the IL-10-transfected group compared to 100% in the mock-transfected group (P < 0.05), and mean pathologic score for EAON was 1.1 in the IL-10-transfected group compared to 2.1 in the mock-transfected group (P < 0.05). When IL-10-transfected mDC were injected in the effector phase, mean EAE clinical scores were not significantly different between the two groups (2.0 vs. 3.0), while the mean EAON pathologic score was lower in the IL-10-transfected group compared to the mock-transfected group (1.0 vs. 2.7, P < 0.05). Delayed hypersensitivity was suppressed significantly in the IL-10-transfected group. Interestingly, the proportions of CD80/86⁺ and MHC class II⁺ cells decreased significantly (P < 0.05), whereas Foxp3⁺ cells increased significantly in the spleen and lymph node in the IL-10-transfected group by flow cytometry analysis. Immunohistochemical analysis demonstrated the localization of IL-10-transfected GFP-expressing mDC not only in the spleen and lymph nodes but also in the inflamed optic nerve. CONCLUSIONS: Treatment with IL-10-expressing mDC was effective in suppressing the development of EAON and EAE.

Visual functional and histopathological correlation in experimental autoimmune optic neuritis.

PURPOSE: To elucidate the correlation between visual threshold of optokinetic tracking (OKT), visual evoked potential (VEP), and histopathology at different time points after induction of experimental autoimmune optic neuritis (EAON). METHODS: EAON was induced in C57BL/6 mice by subcutaneous immunization with an emulsified mixture of myelin oligodendrocyte glycoprotein (MOG)(35-55) peptide. OKT and VEP were measured on days 7, 14, 21, 28, and 42 postimmunization. After VEP measurements, the mice were killed and their eyes were enucleated for histopathological studies. Immunohistochemical staining was performed using cell-specific markers for characterization of cells in the optic nerve: CD3 (T cells), Iba-1 (microglia), MBP (myelin basic protein), and neurofilament (axons). RESULTS: Functionally, OKT threshold decreased as early as day 7, and VEP latency was significantly prolonged on day 21. Axon degeneration was observed as early as day 14. Activated microglia infiltration was also observed on day 14, before T cell infiltration, which peaked on day 21. Demyelination, confirmed by MBP staining, was observed on day 21. CONCLUSIONS: Microglial infiltration in the optic nerve coincided with decline in OKT threshold and preceded VEP latency prolongation, while VEP latency prolongation coincided with T cell infiltration and demyelination of the optic nerve. These findings may contribute to understanding of the pathophysiology of optic neuritis and future development of more effective therapeutic strategy for refractory optic neuritis.

Suppression of murine experimental autoimmune optic neuritis by mature dendritic cells transfected with calcitonin gene-related Peptide gene.

PURPOSE: Calcitonin gene-related peptide (CGRP) exhibits prominent anti-inflammatory actions. We examined whether CGRP-transfected dendritic cells (DC) prevent the development of experimental autoimmune optic neuritis (EAON) and experimental autoimmune encephalomyelitis (EAE). METHODS: A human CGRP-expressing plasmid was constructed, and used to transfect C57BL/6 mouse bone marrow-derived matured DC (mDC) by electroporation METHODS: Transfection efficiency was 50% with 80% cell viability. C57BL/6 mice were immunized with myelo-oligodendrocyte glycoprotein 35-55, and injected intravenously with CGRP-expressing mDC (CGRP gene-transfected group) or mock-transfected mDC (mock-transfected group) at the induction or effector phase. EAE was diagnosed clinically and EAON was assessed histopathologically. Delayed hypersensitivity was measured. Supernatants of spleen cell cultures were assayed for cytokines using ELISA. The CD4(+)CD25(+)Foxp3(+) fraction in spleen cells was analyzed using flow cytometry. RESULTS: For gene therapy in the induction phase, EAE developed in 50% of mice in the CGRP-transfected group compared with 80% in the mock-transfected group, and the mean pathological score for EAON was 1 in the CGRP-transfected group compared with 2 in the mock-transfected group (P < 0.05). For gene therapy in the effector phase, the mean EAE clinical score (1.5 vs. 3.0) and mean EAON pathological score (1.0 vs. 2.0) were both lower in the CGRP-transfected group compared with the mock-transfected group (P < 0.05). Delayed hypersensitivity was suppressed significantly in the CGRP-transfected group. IL-10 production by spleen cells in the CGRP-transfected group increased independent of MOG concentration, compared with the mock-transfected group. Interestingly, the proportion of CD4(+)CD25(+)Foxp3(+) cells increased significantly (P < 0.05) in the CGRP-transfected group compared with the mock-transfected group. CONCLUSIONS: Gene therapy with CGRP-expressing mDC was effective in suppressing the development of EAON and EAE.

Immune mediators in vitreous fluids from patients with vitreoretinal B-cell lymphoma.

PURPOSE: Various immune mediators are hypothesized to have important roles in the pathogenesis of vitreoretinal B-cell lymphoma, although the exact mechanisms remain unclear. We determined the immune mediator profile in the vitreous of eyes with vitreoretinal B-cell lymphoma. METHODS: We studied 28 eyes (23 patients) with vitreoretinal B-cell lymphoma, and 27 eyes (27 patients) undergoing vitrectomy for macular hole and epiretinal membrane served as controls. Undiluted vitreous samples were collected, and cytometric bead array and ELISA were used to determine the vitreous concentrations of 38 immune mediators, including 14 interleukins (IL); interferon (IFN)-γ; oncostatin M (OSM); IFN-γ-inducible protein (IP)-10; monocyte chemoattractant protein (MCP)-1; macrophage inflammatory protein (MIP)-1α; MIP-1ß, regulated on activation, normal T-cell expressed and secreted (RANTES); monokine induced by IFN-γ (Mig); stromal cell-derived factor (SDF)-1α; B-cell-attracting chemokine (BCA)-1; basic fibroblast growth factor (bFGF); Fas ligand; granzyme A; and granzyme B. RESULTS: Vitreous levels of BCA-1, bFGF, Fas ligand, granzyme A, granzyme B, IFN-γ, IL-6, IL-8, IL-10, IP-10, MCP-1, Mig, MIP-1α, MIP-1ß, OSM, RANTES, and SDF-1α were significantly higher in vitreoretinal B-cell lymphoma patients than in controls. A moderate-to-strong positive correlation was observed between granzyme A and BCA-1, IFN-γ, or MIP-1ß; between IFN-γ and Mig or SDF-1α; between IL-6 and IL-8, IL-10, IP-10, or MCP-1; between IL-8 and MCP-1, Mig, or MIP-1ß; between IL-10 and MCP-1 or MIP-1α; between Mig and IP-10 or Mig; and between MIP-1α and MIP-1ß. CONCLUSIONS: Our study suggested that elevated vitreous levels of various immune mediators inducing growth, migration, and apoptosis of B-cell lymphoma are involved possibly in the pathophysiology of vitreoretinal B-cell lymphoma.

Relationship between NMO-antibody and anti-MOG antibody in optic neuritis.

BACKGROUND: Damage to astrocytes by anti-aquaporin-4 antibody (AQP4-Ab), also known as NMO antibody, has been implicated as the cause of neuromyelitis optica. Myelin oligodendrocyte glycoprotein (MOG) is well known as the causative protein of multiple sclerosis (MS). MOG antigen is currently considered as a cause of optic neuritis (ON) associated with MS because immunization with MOG antigen derived from oligodendrocytes induces murine ON with myelitis. We investigated the relationship between NMO antibody (NMO-Ab) and anti-MOG antibody (MOG-Ab) and potential in patients with ON for recovery of vision. METHODS: Thirty-three eyes of 23 patients with ON were studied. At presentation, serum NMO-Ab was measured by immunofluorescence using HEK 293 cells transfected with AQP4-GFP, and anti-MOG1-125 antibody was measured by enzyme-linked immunosorbent assay. MOG-Ab seropositivity was defined by comparing with MOG-Ab level obtained from 8 healthy normal subjects. RESULTS: Eleven (47%) of 23 ON patients were NMO-Ab seropositive, while 8 (34%) of the 23 patients were MOG-Ab seropositive. Six (26%) of 23 patients were seropositive for both NMO-Ab and MOG-Ab. Ten (43%) of 23 patients were seronegative for both antibodies. Three (50%) of 6 eyes of patients seropositive for both antibodies did not respond to corticosteroid pulse therapy and plasmapheresis, and visual acuity remained unchanged. In the NMO-Ab/MOG-Ab group, visual acuity improved significantly (P < 0.0001). In the other 3 groups (NMO-Ab/MOG-Ab, NMO-Ab/MOG-Ab, and NMO-Ab/MOG-Ab), visual acuity did not change significantly (P = 0.53, 0.42, and 0.45, respectively). CONCLUSION: NMO-Ab and MOG-Ab could be potential biomarkers to determine visual prognosis in patients with ON.

Expression and function of inducible costimulator on peripheral blood CD4+ T cells in Behçet's patients with uveitis: a new activity marker?

PURPOSE: Inducible costimulator (ICOS) is an important costimulatory molecule involved in T-cell activation. In this study, the role of ICOS in the pathogenesis of uveitis in Behçet's disease (BD) was investigated. METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from BD patients with uveitis in the active or remission phase and in healthy subjects. Total RNA was isolated from PMBCs, and mRNA expression was analyzed on an oligonucleotide microarray. ICOS expression on CD4(+) T cells was determined by flow cytometry, and the functional costimulatory effect of ICOS/B7RP-1 interaction was assessed on stimulation with concanavalin A (conA) or IRBP in the presence or absence of anti-ICOS mAb. RESULTS: As the result of microarray analysis, ICOS in PBMCs showed the greatest difference in expression in BD patients with uveitis compared with healthy control subjects. ICOS expression on CD4(+) T cells in BD patients with uveitis was significantly higher than that in healthy individuals, both before and after conA stimulation. Among the BD patients, ICOS expression on CD4(+) T cells was significantly higher in those with active uveitis than in those with remitted uveitis. Blockade of ICOS/B7-related protein-1 (B7RP-1) interaction by anti-ICOS mAb significantly decreased IFN-γ, IL-17, and TNF-α production by PBMCs when stimulated with conA or IRBP in BD with active uveitis. CONCLUSIONS: High ICOS expression in BD patients with uveitis contributed to the upregulation of IFN-γ, IL-17, and TNF-α production, suggesting that abnormal ICOS costimulation may play an immunopathologic role in the pathogenesis of uveitis in BD.