Hiroshi Mochimaru

Immune Suppression and Resistance Mediated by Constitutive Activation of Wnt/β-Catenin Signaling in Human Melanoma Cells

Cancer-induced immunosuppression is a major problem reducing antitumor effects of immunotherapies, but its molecular mechanism has not been well understood. We evaluated immunosuppressive roles of activated Wnt/β-catenin pathways in human melanoma for dendritic cells (DCs) and CTLs. IL-10 expression was associated with β-catenin accumulation in human melanoma cell lines and tissues and was induced by direct β-catenin/TCF binding to the IL-10 promoter. Culture supernatants from β-catenin–accumulated melanoma have activities to impair DC maturation and to induce possible regulatory DCs. Those immunosuppressive culture supernatant activities were reduced by knocking down β-catenin in melanoma cells, partly owing to downregulation of IL-10. Murine splenic and tumor-infiltrating DCs obtained from nude mice implanted with human mutant β-catenin–overexpressed melanoma cells had less ability to activate T cells than did DCs from mice with control melanoma cells, showing in vivo suppression of DCs by activated Wnt/β-catenin signaling in human melanoma. This in vivo DC suppression was restored by the administration of a β-catenin inhibitor, PKF115-584. β-catenin–overexpressed melanoma inhibited IFN-γ production by melanoma-specific CTLs in an IL-10–independent manner and is more resistant to CTL lysis in vitro and in vivo. These results indicate that Wnt/β-catenin pathways in human melanoma may be involved in immunosuppression and immunoresistance in both induction and effector phases of antitumor immunoresponses partly through IL-10 production, and they may be attractive targets for restoring immunocompetence in patients with Wnt/β-catenin–activated melanoma.

Predictive factors for non-response to intravitreal ranibizumab treatment in age-related macular degeneration

Background/aims To study the initial characteristics and response to intravitreal ranibizumab (IVR) treatment of age-related macular degeneration (AMD). Methods We reviewed the clinical records of 141 eyes in 141 AMD patients who received monthly IVR for 3 months and thereafter pro re nata (PRN) injections for 9 months as the first treatment for AMD. Patients whose best corrected visual acuity (BCVA) worsened at month 12, and those with increased exudative fundus findings after IVR or an increased central retinal thickness of more than 100 μm at month 12, were considered to be non-responders as judged by BCVA and fundus findings, respectively. Non-responders’ initial characteristics were analysed using logistic regression models. Results 14.9% of eyes were non-responders as judged by BCVA, and 17.0% were non-responders as judged by fundus findings. Initial fibrovascular pigment epithelial detachment (PED) (OR 22.9, 95% CI 2.61 to 201) and serous PED (OR 4.12, 95% CI 1.08 to 15.8) were associated with non-response as judged by BCVA. Initial fibrovascular PED (OR 33.5, 95% CI 2.95 to 381) and type 1 choroidal neovascularization (OR 6.46, 95% CI 1.39 to 30.0) were associated with non-response, as judged by fundus findings. Conclusions Although most AMD responded to IVR, non-responders had initial clinical characteristics that might be informative for managing their treatment.

Suppression of Alkali Burn-Induced Corneal Neovascularization by Dendritic Cell Vaccination Targeting VEGF Receptor 2

PURPOSE To investigate whether the induction of cytotoxic T lymphocytes (CTLs) targeting VEGF receptor 2 inhibits corneal neovascularization caused by alkali injury. METHODS H-2Db-restricted peptide corresponding to amino acids 400 to 408 of VEGF receptor 2 (VEGFR2(400-408)) was used as an epitope peptide. Dendritic cells (DCs) were harvested from bone marrow progenitors of C57BL/6 mice. Six-week-old C57BL/6 mice received subcutaneous injections of VEGFR2(400-408)- or gp70-pulsed mature DCs three times at 6-day intervals. After the third immunization, corneal neovascularization was induced by alkali injury. Two weeks after the injury, the corneal vascularized area was evaluated by lectin angiography. To confirm the peptide-specific CTL activities in C57BL/6 mice, CD8(+) T cells from immunized mice were subjected to ELISA for interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production and (51)Cr-release cytotoxicity assay. To determine the in vivo effector T cells, the immunized mice were intraperitoneally injected with an anti-CD4 or -CD8 depletion antibody. RESULTS Corneal neovascularization was significantly attenuated in mice immunized with VEGFR2(400-408) compared with those not immunized or immunized with gp70. VEGFR2(400-408) or gp70, but not beta-gal(96-103), application led to dose-dependent induction of IFN-gamma and TNF-alpha in the CD8(+) T cells cocultured with stimulator cells. Cytotoxicity assays showed the specific lysis of major histocompatibility complex-matched cells expressing VEGFR2, but not beta-gal(96-103). In vivo depletion of CD8(+), but not CD4(+), T cells significantly reversed the suppressive effect of VEGFR2(400-408) immunization on corneal neovascularization to the level observed in nonimmunized or gp70-immunized animals. CONCLUSIONS These results indicate the possibility of DC vaccination targeting VEGFR2 as a novel therapeutic strategy for corneal chemical injury.

Involvement of hyaluronan and its receptor CD44 with choroidal neovascularization

PURPOSE CD44 is a cell-surface adhesion molecule and receptor for hyaluronan (HA), one of the major extracellular matrix components. The purpose of the present study was to clarify a role of HA and CD44 in the development of choroidal neovascularization (CNV). METHODS Laser photocoagulation was used to induce CNV in C57BL/6 mice or CD44-deficient mice. The mRNA expression of CD44 and HA synthase (HAS)-2 in the retinal pigment epithelium (RPE)-choroid complex was evaluated by DNA microarray and real-time RT-PCR analyses 3 days after laser treatment. HA synthesis and CD44 expression were examined by immunohistochemistry 1 week after photocoagulation. Mice with laser-induced CNV were systemically administered the HA synthesis inhibitor 4-methylumbelliferone (MU) or an anti-CD44-neutralizing antibody. The response of CNV was analyzed by volumetric measurements 1 week after photocoagulation. Macrophage infiltration into CNV lesions was evaluated by real-time RT-PCR for F4/80 3 days after laser-induced injury. RESULTS The induction of CNV led to a significant increase in expression of CD44 and HAS2 mRNA. HA and CD44 were immunopositive in the CNV lesions. Compared with vehicle treatment, the systemic application of MU significantly attenuated CNV volume in a dose-dependent fashion, together with macrophage infiltration into the lesions. Consistently, antibody-based blockade of CD44 resulted in a significant reduction of CNV volume, compared with the isotype control. In contrast, genetic ablation of CD44 significantly augmented CNV formation together with HA accumulation and macrophage infiltration, compared with wild-type mice. CONCLUSIONS These results indicate a significant role of HA and its receptor CD44 in the development of CNV.

Detection of early visual impairment in patients with epiretinal membrane.

Purpose:  Patients with epiretinal membrane sometimes complain of impaired central visual function, despite good best corrected visual acuity (BCVA), as measured by visual acuity (VA) charts. Here, we evaluate early epiretinal membrane–induced changes in central VA.

Association of macular pigment optical density with serum concentration of oxidized low-density lipoprotein in healthy adults

Purpose: To analyze the association between macular pigment optical density (MPOD), which reflects lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) in the macula, and background characteristics. Methods: Fifty-five healthy adult volunteers were analyzed. Macular pigment optical density was measured using a heterochromatic flicker photometry technique, and serum concentrations of carotenoids and lipoproteins were by high-performance liquid chromatography and enzyme-linked immunosorbent assay, respectively. Dietary intake of nutrient was determined by a validated self-administered questionnaire on ingestion frequency. Results: Macular pigment optical density was positively correlated with serum concentrations of L and Z and dietary L intake and inversely correlated with serum oxidized low-density lipoprotein (LDL). Although MPOD decreased with age (95% confidence interval, −0.011 to −0.002; correlation coefficient, −0.269; P = 0.007), serum L/Z and dietary L intake did not. In contrast, serum oxidized LDL was positively correlated with age (95% confidence interval, 0.69–2.34; correlation coefficient, 0.333; P = 0.0004). After adjusting for age, sex, and oxidized LDL, serum L was positively correlated with MPOD (95% confidence interval, 0.88–1.69; P = 0.000001). After adjusting for age, sex, and serum L, serum oxidized LDL was inversely correlated with MPOD (95% confidence interval, −0.002 to −0.0004; P = 0.006). Conclusion: Macular pigment optical density was inversely correlated with serum oxidized LDL. Further study to know the impact of oxidized LDL on MPOD may be warranted.

Functional Visual Acuity in Age-Related Macular Degeneration.

Purpose We evaluated whether a functional visual acuity (FVA) system can detect subtle changes in central visual acuity that reflect pathological findings associated with age-related macular degeneration (AMD). Methods Twenty-eight patients with unilateral AMD and logMAR monocular best corrected VA better than 0 in both eyes, as measured by conventional chart examination, were analyzed between November 2012 and April 2013. After measuring conventional VA, FVA, and contrast VA with best correction, routine eye examinations including spectral domain–optical coherence tomography were performed. Standard Schirmer test was performed, and corneal and lens densities were measured. Results The FVA score (p < 0.001) and visual maintenance ratio (p < 0.001) measured by the FVA system, contrast VA (p < 0. 01), and conventional VA (p < 0.01) were significantly worse in the AMD-affected eyes than in the fellow eyes. No significant differences were observed in the anterior segment conditions. Forward stepwise regression analysis demonstrated that the length of interdigitation zone disruption, as visualized by optical coherence tomography imaging, correlated with the FVA score (p < 0.01) but not with any other parameters investigated. Conclusions The FVA system detects subtle changes in best corrected VA in AMD-affected eyes and reflects interdigitation zone disruption, an anatomical change in the retina recorded by optical coherence tomography. Further studies are required to understand the value of the FVA system in detecting subtle changes in AMD.

Association of Maternal Age to Development and Progression of Retinopathy of Prematurity in Infants of Gestational Age under 33 Weeks

Aim. To find predictive and indicative markers of risk for development of retinopathy of prematurity (ROP) and its progression to the stage requiring laser treatment, in premature infants whose gestational age (GA) was under 33 weeks. Methods. We retrospectively reviewed medical records of 197 premature infants born in 2005–2010 whose GA < 33 weeks and underwent eye screening at Keio University Hospital. The association between candidate risk factors and development or progression of ROP was assessed. Results. Among the 182 eligible infants (median GA, 29.1 weeks; median birth weight (BW), 1028 g), 84 (46%) developed any stage of ROP, of which 45 (25%) required laser treatment. Multivariate analysis using a stepwise method showed that GA (P = 0.002; 95% confidence interval (CI), 0.508–0.858), BW (P < 0.001; 95% CI, 0.994–0.998), and lower maternal age (P = 0.032; 95% CI, 0.819–0.991) were the risk factors for ROP development and GA (P < 0.001; 95% CI, 0.387–0.609) and lower maternal age (P = 0.012; 95% CI, 0.795–0.973) were for laser treatment. The odds ratio of requiring laser treatment was 3.3 when the maternal age was <33 years. Conclusion. ROP was more likely to be developed and progressed in infants born from younger mother and low GA.