Functions of mucosal associated invariant T cells in eye diseases.

Mucosal-associated invariant T (MAIT) cells are a unique subset of T cells that recognizes metabolites derived from the vitamin B2 biosynthetic pathway. Since the identification of cognate antigens for MAIT cells, knowledge of the functions of MAIT cells in cancer, autoimmunity, and infectious diseases has been rapidly expanding. Recently, MAIT cells have been found to contribute to visual protection against autoimmunity in the eye. The protective functions of MAIT cells are induced by T-cell receptor (TCR)-mediated activation. However, the underlying mechanisms remain unclear. Thus, this mini-review aims to discuss our findings and the complexity of MAIT cell-mediated immune regulation in the eye.

Intraocular human cytomegaloviruses of ocular diseases are distinct from those of viremia and are capable of escaping from innate and adaptive immunity by exploiting HLA-E-mediated peripheral and central tolerance.

Human cytomegalovirus (HCMV) infections develop into CMV diseases that result in various forms of manifestations in local organs. CMV-retinitis is a form of CMV disease that develops in immunocompromised hosts with CMV-viremia after viruses in the peripheral circulation have entered the eye. In the HCMV genome, extensive diversification of the UL40 gene has produced peptide sequences that modulate NK cell effector functions when loaded onto HLA-E and are subsequently recognized by the NKG2A and NKG2C receptors. Notably, some HCMV strains carry UL40 genes that encode peptide sequences identical to the signal peptide sequences of specific HLA-A and HLA-C allotypes, which enables these CMV strains to escape HLA-E-restricted CD8+T cell responses. Variations in UL40 sequences have been studied mainly in the peripheral blood of CMV-viremia cases. In this study, we sought to investigate how ocular CMV disease develops from CMV infections. CMV gene sequences were compared between the intraocular fluids and peripheral blood of 77 clinical cases. UL40 signal peptide sequences were more diverse, and multiple sequences were typically present in CMV-viremia blood compared to intraocular fluid. Significantly stronger NK cell suppression was induced by UL40-derived peptides from intraocular HCMV compared to those identified only in peripheral blood. HCMV present in intraocular fluids were limited to those carrying a UL40 peptide sequence corresponding to the leader peptide sequence of the host's HLA class I, while UL40-derived peptides from HCMV found only in the peripheral blood were disparate from any HLA class I allotype. Overall, our analyses of CMV-retinitis inferred that specific HCMV strains with UL40 signal sequences matching the host's HLA signal peptide sequences were those that crossed the blood-ocular barrier to enter the intraocular space. UL40 peptide repertoires were the same in the intraocular fluids of all ocular CMV diseases, regardless of host immune status, implying that virus type is likely to be a common determinant in ocular CMV disease development. We thus propose a mechanism for ocular CMV disease development, in which particular HCMV types in the blood exploit peripheral and central HLA-E-mediated tolerance mechanisms and, thus, escape the antivirus responses of both innate and adaptive immunity.

Panuveitis induced by donor-derived CD8+ T cells after allogeneic hematopoietic stem cell transplantation for adult T-cell leukemia.

Purpose: This article presents a case of panuveitis that occurred after unrelated allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a patient with lymphoma-type human T-cell leukemia virus type-1 (HTLV-1)-associated adult T-cell leukemia (ATL). Observations: A 45-year-old man developed unilateral panuveitis 18 months after undergoing allo-HSCT. He underwent vitrectomy, and depositions of grey-white granules localized on the retinal artery were observed in the eye. Cytological examination of the vitreous aspirates showed that the atypical lymphoid cells stained positive for CD3 and CD8, but negative for CD4, B-cell markers, and cytomegalovirus antigen. Interphase fluorescence in situ hybridization using X- and Y-chromosome probes revealed complete donor chimerism in CD8+ T cells in the vitreous aspirates. Conclusions and importance: Donor-derived CD8+ T lymphocytes can induce panuveitis like HTLV-1-assiciated uveitis after allo-HSCT in patients with ATL. Pathological diagnosis of vitreous infiltration by vitrectomy is helpful in patients with ATL. Donor-derived CD8+ T lymphocytes-induced panuveitis is recurrent but susceptible to regional corticosteroid treatment.

Increased vitreous levels of B cell activation factor (BAFF) and soluble interleukin-6 receptor in patients with macular edema due to uveitis related to Behçet's disease and sarcoidosis.

PURPOSE: Uveitis accounts for 10-15% of all cases of blindness in the developed world. Uveitic macular edema (UME) is a primary cause of permanent visual impairment in patients with uveitis. Because proinflammatory mediators elicit inflammation and lead to UME, we determined the profiles of proinflammatory mediators associated with complications, such as ME, in the vitreous humor of patients with panuveitis related to Behçet's disease (BD) and sarcoidosis. METHODS: In this retrospective study, we enrolled 21 patients with uveitis, including 6 with BD and 15 with sarcoidosis, and 15 patients with idiopathic epiretinal membrane (iERM) at the Department of Ophthalmology, Kyushu University Hospital, between January 2008 and April 2016. Vitreous concentrations of 32 proinflammatory mediators, including cytokines and soluble receptors of tumor necrosis factor (TNF) and interleukin (IL)-6 families, were assessed using a bead-based multiplex assay and their association with clinical data was examined. RESULTS: The levels of proinflammatory mediators, including a proliferation-inducing ligand (APRIL), B cell activating factor belonging to the TNF family (BAFF), soluble cluster of differentiation 30 (sCD30), soluble TNF receptor-1 (sTNFR1), sTNFR2, TNF-α, IL-6, and soluble IL-6 receptor-α (sIL-6Rα), were significantly higher in patients with uveitis. With regard to clinical parameters in patients with uveitis, vitreous levels of BAFF and sIL-6Rα were prominently elevated in patients with UME compared to in those without UME (P < 0.01, respectively). CONCLUSIONS: Our results suggest that elevated vitreous levels of BAFF and sIL-6Rα are associated with the pathogenesis of UME in patients with panuveitis related to BD and sarcoidosis.

Surgical Outcomes of Contrast Sensitivity and Visual Acuity in Uveitis-Associated Cataract.

PURPOSE: To evaluate the pre- and post-operative outcomes of phacoemulsification in patients with uveitis-associated cataract in remission, such as conventional visual acuity (VA), photopic and mesopic contrast visual acuity (CVA), and flares in the anterior chamber objectively assessed as intraocular inflammation. PATIENTS AND METHODS: This prospective study included 26 eyes of 19 patients with uveitis and 45 eyes of 26 controls who underwent cataract surgery at the Kyushu University Hospital and Kyushu Medical Center in Fukuoka, Japan, from October 2016 to December 2018. Conventional VA and flare values in the anterior chamber were evaluated preoperatively and 1 and 3 months postoperatively. Photopic and mesopic CVAs were assessed preoperatively and 3 months postoperatively. RESULTS: The best-corrected VA (BCVA) was improved significantly from baseline to 1 and 3 months postoperatively in both groups (P < 0.01 in both groups). The mean preoperative 100% and 10% CVAs under the photopic condition were significantly lower in the uveitis group than in the control group (P < 0.05 for both CVA), whereas the mean preoperative 100% CVA under the mesopic condition was comparable between the two groups. Although the mean preoperative 100% and 10% CVAs improved significantly from baseline under both photopic and mesopic conditions in both groups (P < 0.01 in both groups), the postoperative contrast sensitivities under both photopic and mesopic conditions remained lower in the uveitis group than in the control group (P < 0.01 for both conditions). The postoperative complications included recurrence of active inflammation in five eyes and cystoid macular edema in one eye and were managed by topical steroid therapy alone. CONCLUSION: Cataract surgery for uveitis-associated cataracts during remission is well tolerated. However, the present results suggest that amelioration of hemeralopia and/or nyctalopia is not as good as expected after cataract surgery in patients with uveitis.

Distinguishing Features of Anterior Uveitis Caused by Herpes Simplex Virus, Varicella-Zoster Virus, and Cytomegalovirus.

PURPOSE: To determine distinguishing features of the clinical characteristics of anterior uveitis (AU) caused by herpes simplex virus (HSV), varicella-zoster virus (VZV), and cytomegalovirus (CMV). DESIGN: Retrospective, multicenter case series. METHODS: Consecutive patients with herpetic AU examined at 11 tertiary centers in Japan between January 2012 and December 2017 and who were followed for ≥3 months were evaluated. Diagnosis was made by polymerase chain reaction (PCR) for HSV, VZV, or CMV in the aqueous humor, or classical signs of herpes zoster ophthalmicus. RESULTS: This study enrolled 259 herpetic AU patients, including PCR-proven HSV-AU (30 patients), VZV-AU (50), and CMV-AU (147), and herpes zoster ophthalmicus (32). All HSV-AU and VZV-AU patients were unilateral, while 3% of CMV-AU patients were bilateral. Most HSV-AU and VZV-AU patients were sudden onset with an acute clinical course, while CMV-AU had a more insidious onset and chronic course. There were no significant differences for all surveyed symptoms, signs, and complications between HSV-AU and VZV-AU. However, significant differences were detected for many items between CMV-AU and the other two herpetic AU types. Ocular hyperemia and pain, blurring of vision, ciliary injection, medium-to-large keratic precipitates (KPs), cells and flare in the anterior chamber, and posterior synechia significantly more often occurred in HSV-AU and VZV-AU vs CMV-AU. In contrast, small KPs, coin-shaped KPs, diffuse iris atrophy, elevated intraocular pressure, and glaucoma surgery were significantly more frequent in CMV-AU vs HSV-AU and VZV-AU. CONCLUSION: This multicenter, retrospective study identified distinguishing features of HSV-AU, VZV-AU, and CMV-AU.

Epidemiology of uveitis in Japan: a 2016 retrospective nationwide survey.

PURPOSE: To investigate the epidemiology of uveitis in Japan and assess its changes over time. STUDY DESIGN: Retrospective multicenter study METHODS: Sixty-six hospitals in Japan with uveitis specialty clinics participated in this retrospective nationwide survey. A questionnaire was sent to each hospital to survey the total number of patients who made a first visit to the outpatient uveitis clinic of each hospital between 1 April 2016 and 31 March 2017. The diagnosis of uveitis was based on guidelines when available or on commonly used diagnostic criteria. RESULTS: In 2016, new patients with uveitis accounted for 3.2% of the total number of new patients with ophthalmic diseases. A total of 5378 patients were enrolled in the survey; 3408 cases could be classified with a specific uveitis entity, and 1970 cases were described as unclassified intraocular inflammation. Among the classified cases, the most frequent disease was sarcoidosis (10.6%), followed by Vogt-Koyanagi-Harada disease (8.1%), herpetic iritis (6.5%), acute anterior uveitis (5.5%), sclerouveitis (4.4%), Behçet's disease (4.2%), malignant disease (2.6%), acute retinal necrosis (1.7%), Posner-Schlossman syndrome (1.7%), and diabetic iritis (1.4%). The rates of sarcoidosis, Vogt-Koyanagi-Harada disease, and Behçet's disease were similar; however, the rate of herpes iritis increased (4.2-6.5%) when compared with the 2009 survey. CONCLUSIONS: Some changes were observed between the previous nationwide surveys (2002 and 2009) and the present survey. It must be valuable to continue such nationwide epidemiologic surveys at regular intervals.

Vitreous levels of interleukin-35 as a prognostic factor in B-cell vitreoretinal lymphoma.

Vitreoretinal lymphoma (VRL) is a rare disease of B-cell origin with poor prognosis. Regulatory cytokines promote tumor development by suppressing antitumor immunity in several cancer types, including B-cell malignancies. To identify the regulatory cytokines associated with poor prognosis in patients with B-cell VRL, we determined the regulatory cytokines profiles in the vitreous humor of patients with VRL. This retrospective study included 22 patients with VRL, 24 with non-infectious uveitis (NIU), and 20 with idiopathic epiretinal membrane (control). Vitreous concentrations of regulatory cytokines were assessed using a cytometric beads assay and association with clinical data was examined. IL-35 and soluble IL-2 receptor α levels were significantly higher in patients with VRL and NIU than those in the control group. The 5-year overall survival (OS) rates for the group with high intravitreal IL-35 was significantly poorer than those for the group with low intravitreal IL-35, who were diagnosed with VRL at the onset (P = 0.024, log-rank test). The 5-year OS rates with intravitreal IL-35 levels above and below the median were 40.0% and 83.3%, respectively. Our results suggest that high intravitreal IL-35 levels indicate poor prognosis for patients diagnosed with B-cell VRL at the onset.

RIP1 kinase mediates angiogenesis by modulating macrophages in experimental neovascularization.

Inflammation plays an important role in pathological angiogenesis. Receptor-interacting protein 1 (RIP1) is highly expressed in inflammatory cells and is known to play an important role in the regulation of apoptosis, necroptosis, and inflammation; however, a comprehensive description of its role in angiogenesis remains elusive. Here, we show that RIP1 is abundantly expressed in infiltrating macrophages during angiogenesis, and genetic or pharmacological inhibition of RIP1 kinase activity using kinase-inactive RIP1K45A/K45A mice or necrostatin-1 attenuates angiogenesis in laser-induced choroidal neovascularization, Matrigel plug angiogenesis, and alkali injury-induced corneal neovascularization in mice. The inhibitory effect on angiogenesis is mediated by caspase activation through a kinase-independent function of RIP1 and RIP3. Mechanistically, infiltrating macrophages are the key target of RIP1 kinase inhibition to attenuate pathological angiogenesis. Inhibition of RIP1 kinase activity is associated with caspase activation in infiltrating macrophages and decreased expression of proangiogenic M2-like markers but not M1-like markers. Similarly, in vitro, catalytic inhibition of RIP1 down-regulates the expression of M2-like markers in interleukin-4-activated bone marrow-derived macrophages, and this effect is blocked by simultaneous caspase inhibition. Collectively, these results demonstrate a nonnecrotic function of RIP1 kinase activity and suggest that RIP1-mediated modulation of macrophage activation may be a therapeutic target of pathological angiogenesis.

The effectiveness of adalimumab treatment for non-infectious uveitis.

Uveitis, which is a major cause of blindness worldwide, is defined as intraocular inflammation that affects the iris, ciliary body, vitreous, retina and choroid. Tumor necrosis factor-alpha (TNF-α) is a key cytokine involved in the pathogenesis of many inflammatory diseases including uveitis. Corticosteroids and immunosuppressive agents are the conventional therapy to treat non-infectious uveitis. In cases that are resistant to these therapies, anti-TNF agents are added. An anti-TNF-α agent, adalimumab, was recently approved for the treatment of refractory non-infectious uveitis. In this review, we provide an introduction to uveitis and summarize the effectiveness and safety of adalimumab in the treatment of non-infectious uveitis.

Risk factors for failure of vitrectomy cell block technique in cytological diagnosis of vitreoretinal lymphoma.

PURPOSE: To determine the factors that may affect the accuracy of vitrectomy cell block technique in detecting atypical lymphoid cells in patients with vitreoretinal lymphoma (VRL). METHODS: We retrospectively reviewed 43 eyes in 39 patients who underwent vitrectomy for definitive histological diagnosis of VRL with vitrectomy cell block technique and/or smear preparation at Kyushu University Hospital from January 2001 to March 2016. The association of detection of atypical lymphoid cells using vitrectomy cell block technique with the following factors was assessed using logistic regression analysis: age at diagnosis, sex, presence or absence of concurrent cataract surgery with vitrectomy, clinical grading of vitreous haze, presence or absence of subretinal tumor infiltration, interval between initial symptoms and vitrectomy, and presence or absence of systemic corticosteroid therapy before vitrectomy. RESULTS: Atypical lymphoid cells were more significantly detected using vitrectomy cell block technique compared to that using smear preparation (p = 0.018). After adjusting for age and sex, concurrent cataract surgery (odds ratio [OR], 10.41; 95% confidence interval [CI], 1.42-76.41) and subretinal tumor infiltration (OR, 5.06; 95% CI, 1.06-24.32) were significantly associated with failure of histological analysis with vitrectomy cell blocks. In multivariable logistic regression analysis, similar results were obtained, although subretinal tumor infiltration was only marginally associated with the detective capability of the technique. CONCLUSION: Vitrectomy cell block technique significantly improved the definitive diagnosis of VRL. Concurrent cataract surgery with vitrectomy and subretinal tumor infiltration were risk factors for failure in vitrectomy cell blocks.

Preoperative estimation of distance between retinal break and limbus with wide-field fundus imaging: Potential clinical utility for conventional scleral buckling.

OBJECTIVE: Accurate scleral marking of retinal breaks is essential for successful scleral buckling. This study aimed to investigate the use of wide-field fundus images obtained with an Optos for preoperative estimation of the distance from the limbus to the retinal breaks. METHODS AND ANALYSIS: This is a retrospective review of 29 eyes from 26 patients with rhegmatogenous retinal detachment who received scleral buckling with anatomically successful repair. They underwent wide-field fundus photography with Optos California. In the pre- and postoperative fundus images, we measured distances from the macula to the retinal tears (TM), to the center of the vortex veins (VM), to the optic disc (DM), and to the posterior edge of the scleral buckle (BM). RESULTS: (BM-VM) / DM was significantly correlated with the distance from the limbus to the posterior edge of the scleral buckle that had been determined intraoperatively. (r = 0.705; p<0.001) We applied a regression line derived from this correlation with the value of (TM -VM) / DM in order to calculate estimated distances between retinal breaks and the limbus. The calculated distances were all within the range of distances from the limbus to the anterior and posterior edges of the scleral buckles. CONCLUSION: Preoperative analysis of Optos images may be useful for estimating the distance from the limbus to retinal breaks, which might aid scleral marking during scleral buckling surgery.

Cytochrome P450 monooxygenase lipid metabolites are significant second messengers in the resolution of choroidal neovascularization.

Age-related macular degeneration (AMD) is the most common cause of blindness for individuals age 50 and above in the developed world. Abnormal growth of choroidal blood vessels, or choroidal neovascularization (CNV), is a hallmark of the neovascular (wet) form of advanced AMD and leads to significant vision loss. A growing body of evidence supports a strong link between neovascular disease and inflammation. Metabolites of long-chain polyunsaturated fatty acids derived from the cytochrome P450 (CYP) monooxygenase pathway serve as vital second messengers that regulate a number of hormones and growth factors involved in inflammation and vascular function. Using transgenic mice with altered CYP lipid biosynthetic pathways in a mouse model of laser-induced CNV, we characterized the role of these lipid metabolites in regulating neovascular disease. We discovered that the CYP-derived lipid metabolites epoxydocosapentaenoic acids (EDPs) and epoxyeicosatetraenoic acids (EEQs) are vital in dampening CNV severity. Specifically, overexpression of the monooxygenase CYP2C8 or genetic ablation or inhibition of the soluble epoxide hydrolase (sEH) enzyme led to increased levels of EDP and EEQ with attenuated CNV development. In contrast, when we promoted the degradation of these CYP-derived metabolites by transgenic overexpression of sEH, the protective effect against CNV was lost. We found that these molecules work in part through their ability to regulate the expression of key leukocyte adhesion molecules, on both leukocytes and endothelial cells, thereby mediating leukocyte recruitment. These results suggest that CYP lipid signaling molecules and their regulators are potential therapeutic targets in neovascular diseases.

Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury.

Degeneration of photoreceptors is a primary cause of vision loss worldwide, making the underlying mechanisms surrounding photoreceptor cell death critical to developing new treatment strategies. Retinal detachment, characterized by the separation of photoreceptors from the underlying retinal pigment epithelium, is a sight-threatening event that can happen in a number of retinal diseases. The detached photoreceptors undergo apoptosis and programmed necrosis. Given that photoreceptors are nondividing cells, their loss leads to irreversible visual impairment even after successful retinal reattachment surgery. To better understand the underlying disease mechanisms, we analyzed innate immune system regulators in the vitreous of human patients with retinal detachment and correlated the results with findings in a mouse model of retinal detachment. We identified the alternative complement pathway as promoting early photoreceptor cell death during retinal detachment. Photoreceptors down-regulate membrane-bound inhibitors of complement, allowing for selective targeting by the alternative complement pathway. When photoreceptors in the detached retina were removed from the primary source of oxygen and nutrients (choroidal vascular bed), the retina became hypoxic, leading to an up-regulation of complement factor B, a key mediator of the alternative pathway. Inhibition of the alternative complement pathway in knockout mice or through pharmacological means ameliorated photoreceptor cell death during retinal detachment. Our current study begins to outline the mechanism by which the alternative complement pathway facilitates photoreceptor cell death in the damaged retina.

Characterization of a spontaneous retinal neovascular mouse model.

BACKGROUND: Vision loss due to vascular disease of the retina is a leading cause of blindness in the world. Retinal angiomatous proliferation (RAP) is a subgroup of neovascular age-related macular degeneration (AMD), whereby abnormal blood vessels develop in the retina leading to debilitating vision loss and eventual blindness. The novel mouse strain, neoretinal vascularization 2 (NRV2), shows spontaneous fundus changes associated with abnormal neovascularization. The purpose of this study is to characterize the induction of pathologic angiogenesis in this mouse model. METHODS: The NRV2 mice were examined from postnatal day 12 (p12) to 3 months. The phenotypic changes within the retina were evaluated by fundus photography, fluorescein angiography, optical coherence tomography, and immunohistochemical and electron microscopic analysis. The pathological neovascularization was imaged by confocal microscopy and reconstructed using three-dimensional image analysis software. RESULTS: We found that NRV2 mice develop multifocal retinal depigmentation in the posterior fundus. Depigmented lesions developed vascular leakage observed by fluorescein angiography. The spontaneous angiogenesis arose from the retinal vascular plexus at postnatal day (p)15 and extended toward retinal pigment epithelium (RPE). By three months of age, histological analysis revealed encapsulation of the neovascular lesion by the RPE in the photoreceptor cell layer and subretinal space. CONCLUSIONS: The NRV2 mouse strain develops early neovascular lesions within the retina, which grow downward towards the RPE beginning at p15. This retinal neovascularization model mimics early stages of human retinal angiomatous proliferation (RAP) and will likely be a useful in elucidating targeted therapeutics for patients with ocular neovascular disease.

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.

Forced expression of stabilized c-Fos in dendritic cells reduces cytokine production and immune responses in vivo.

Intracellular cyclic adenosine monophosphate (cAMP) suppresses innate immunity by inhibiting proinflammatory cytokine production by monocytic cells. We have shown that the transcription factor c-Fos is responsible for cAMP-mediated suppression of inflammatory cytokine production, and that c-Fos protein is stabilized by IKKß-mediated phosphorylation. We found that S308 is one of the major phosphorylation sites, and that the S308D mutation prolongs c-Fos halflife. To investigate the role of stabilized c-Fos protein in dendritic cells (DCs) in vivo, we generated CD11c-promoter-deriven c-FosS308D transgenic mice. As expected, bone marrow-derived DCs (BMDCs) from these Tg mice produced smaller amounts of inflammatory cytokines, including TNF-α, IL-12, and IL-23, but higher levels of IL-10, in response to LPS, than those from wild-type (Wt) mice. When T cells were co-cultured with BMDCs from Tg mice, production of Th1 and Th17 cytokines was reduced, although T cell proliferation was not affected. Tg mice demonstrated more resistance to experimental autoimmune encephalomyelitis (EAE) than did Wt mice. These data suggest that c-Fos in DCs plays a suppressive role in certain innate and adaptive immune responses.

IL-27 inhibits pathophysiological intraocular neovascularization due to laser burn.

AMD is the most common disease leading to acquired blindness in developed countries. CNV is the foremost cause of AMD and is thought to be induced by regional inflammation as a result of age-related conformational changes of the chorioretinal interface. Here, we show that IL-27, a member of the IL-6/IL-12 cytokine family, has an angiostatic effect and regulates the development of laser-induced experimental CNV in mice. In this model, IL-27 expression increased in the damaged choroid and peaked at the 24 h-time-point. IL-27 neutralization, induced by inoculating an antagonistic antibody into the vitreous cavity, enhanced VEGF production and the extent of CNV. By contrast, the administration of rIL-27 reduced VEGF production and the extent of CNV. Mice deficient in the EBI3, which lack IL-27, also showed more CNV than C57BL/6 mice, and this was reduced by IL-27 supplementation. We additionally investigated the effect of IL-27 on the function of macrophages, which play a critical role in CNV. IL-27 did not affect macrophage migration but inhibited its VEGF production. IL-27 therefore appears to regulate CNV and is a promising candidate target for treating sight-threatening diseases caused by ocular neovascularization.

Suppression of SOCS3 in macrophages prevents cancer metastasis by modifying macrophage phase and MCP2/CCL8 induction.

Inflammation has been demonstrated to play important roles in tumorigenesis, tumor progression, and metastasis. STAT3 has been shown to be frequently activated in a variety of human cancer cells and STAT3 signaling promotes the growth and survival of tumor cells. However, the role of STAT3 of myeloid cells associated with tumors is currently unknown. Suppressor of cytokine signaling-3 (SOCS3) has been shown to be a negative regulator of STAT3. In this study, we used macrophage specific SOCS3 conditional knockout (cKO) mice to investigate the effect of the hyperactivation of STAT3 in macrophages on tumor development and metastasis. In a subcutaneous transplantation model of B16F10 melanoma cells, although tumor sizes were not significantly different, SOCS3-cKO mice survived longer than wild-type (WT) mice did. SOCS3-cKO mice exhibited fewer lung and liver metastatic tumor nodules than WT mice when B16F10 was challenged intravenously. SOCS3(-/-) macrophages stimulated with tumor lysates in vitro exhibited prolonged STAT3 phosphorylation and produced less amount of TNFα and IL-6, and higher amount of MCP2/CCL8 than WT macrophages. MCP/CCL8 was induced via STAT3 and exhibited anti-tumor metastatic effect in WT mice. These data suggest that hyperactivation of STAT3 in myeloid cells simultaneously exerted an anti-inflammatory as well as anti-tumor effects. Thus, the targeted inhibition of SOCS3 activity in macrophages may be therapeutic for the suppression of tumor metastasis.

Choroidal neovascularization enhanced by Chlamydia pneumoniae via Toll-like receptor 2 in the retinal pigment epithelium.

PURPOSE: Choroidal neovascularization (CNV) is directly related to visual loss in persons with age-related macular degeneration (AMD) and other macular disorders. Chlamydia pneumoniae, a prokaryotic pathogen that causes chronic inflammation, is recognized as a risk factor for cardiovascular diseases. In this study, the authors investigated the association between C. pneumoniae infection and AMD using a laser-induced CNV model in mice. METHODS: C57BL/6 mice, myeloid differentiation factor (MyD) 88 knockout (KO) mice, Toll-like receptor (TLR) 2 KO mice, and TLR4 KO mice were used. Experimental CNV was induced by rupturing the Bruch's membrane by laser photocoagulation (PC). Seven days after PC, the eyes were enucleated and the areas of CNV were measured in choroidal flat mounts. Cytokine gene expression by quantitative real-time PCR in the primary cultured retinal pigment epithelium (RPE) cells was also examined. RESULTS: Vitreous injection of the C. pneumoniae antigen increased the size of CNV. Although lipopolysaccharide stimulation can induce multiple cytokines, cultured mouse RPE cells from C57BL/6 mice expressed IL-6 and VEGF, but not TNF-alpha mRNA, in response to C. pneumoniae antigen. RPE cells from either MyD88 KO mice or TLR2 KO mice did not respond to the C. pneumoniae antigen. TLR2 KO mice did not augment the size increase of experimental CNV by C. pneumoniae antigen in vivo. CONCLUSIONS: C. pneumoniae can trigger inflammatory responses in the eye and promote experimental CNV in a TLR2-dependent manner. These data provide experimental evidence to imply persistent C. pneumoniae infection is a risk factor for AMD.