Reiko Yamagishi

Activation of the Prostanoid FP Receptor Inhibits Adipogenesis Leading to Deepening of the Upper Eyelid Sulcus in Prostaglandin-Associated Periorbitopathy

PURPOSE To investigate the effects of prostaglandin (PG) analogues on adipogenesis so as to clarify the mechanism of a side effect of topical PG analogues: deepening of the upper eyelid sulcus (DUES), which has been reported in this decade. METHODS The 3T3-L1 preadipocytes were treated to promote differentiation into mature adipocytes. During the early and late stages of differentiation (days 0, 2, and 7), 1 to 1000 nM latanoprost acid (LAT-A), travoprost acid (TRA-A), tafluprost acid (TAF-A), bimatoprost (BIM), bimatoprost acid (BIM-A), unoprostone (UNO), or prostaglandin F2a (PGF2α) was applied to cells. Oil red O staining was used to detect intracellular lipids on day 10. Stained areas measured on a photograph were compared with those in control cultures. All experiments were performed in a masked manner. Next, similar experiments were performed using primary cultured mouse adipocytes from FP receptor knockout and wild-type mice. RESULTS When PGs were added on day 0 or 2, LAT-A, TAF-A, BIM-A, and PGF2α significantly inhibited adipogenesis (P < 0.01 on day 0, P < 0.05 on day 2) at concentrations of 10 nM and 100 nM, and TRA-A inhibited adipogenesis only at 100 nM. Bimatoprost and UNO did not affect adipogenesis at any concentration. When PGs were added on day 7, 100 nM LAT-A, BIM-A, or PGF2α significantly suppressed adipogenesis (P < 0.05). In mouse primary adipocyte cultures, LAT-A, TAF-A, BIM-A, TRA-A, and PGF2α significantly suppressed adipogenesis in wild-type adipocytes (P < 0.05), but adipogenesis was not suppressed by any of the PG compounds in FP knockout mouse adipocytes. CONCLUSIONS Prostaglandin analogues have the potential to inhibit adipogenesis through FP receptor stimulation. Although these findings should be further analyzed in model systems more closely related to orbital fat, PG analogues may directly lead to reduced orbital fat by inhibiting adipogenesis.

Renin–angiotensin system involvement in the oxidative stress-induced neurodegeneration of cultured retinal ganglion cells

PurposeTo analyze the influence of oxidative stress on retinal ganglion cells (RGCs) by using a selective culture system of rat RGCs.MethodsRat RGCs were purified by a two-step immunopanning procedure and cultured either with or without antioxidant (AO) compounds. Reactive oxygen species (ROS) in RGCs were analyzed using dihydroethidium. Expression of angiotensin II, cleaved caspase 3, and netrin-1 was analyzed by immunocytochemistry. Live RGCs were detected by use of calcein-acetoxymethyl ester. The roles of angiotensin II type 1 receptor (AT1R) signaling and netrin-1 were analyzed by use of an AT1R blocker (telmisartan) and an anti-netrin-1 neutralizing antibody, respectively.ResultsROS and angiotensin II were induced in RGCs cultured without AO compounds (AO−). In these cultures, the number of live RGCs decreased and expression of cleaved and activated caspase 3 increased, but these changes were attenuated by addition of the AT1R blocker. Reduction in netrin-1 expression under the AO− condition was also prevented by the AT1R blocker. The AT1R blocker’s effects on RGC survival and reduction in cleaved caspase 3-positive cells were cancelled by the anti-netrin-1 neutralizing antibody.ConclusionsOxidative stress induced cell death through AT1R signaling and netrin-1 reduction in cultured RGCs.

Choroidal neovascularization is inhibited via an intraocular decrease of inflammatory cells in mice lacking complement component C3

In early age-related macular degeneration (AMD), complement component C3 can be observed in drusen, which is the accumulation of material beneath the retinal pigment epithelium. The complement pathways, via the activation of C3, can upregulate the expression of cytokines and their receptors and the recruitment of inflammatory leukocytes, both of which play an important role in the development of choroidal neovascularization (CNV) in exudative AMD. Laser-induced CNV lesions were found to be significantly smaller in C3−/− mice than in wild-type mice. By using flow cytometry, we demonstrated that the proportions of intraocular granulocytes, CD11b+F4/80+Ly6Chi and CD11b+F4/80+Ly6Clo cells, were lower in C3−/− mice than in wild-type mice as early as day 1 after laser injury, and the proportions of granulocytes and three macrophage/monocyte subsets were significantly lower on day 3. In contrast, C3−/− mice had more granulocytes and CD11b+F4/80+Ly6Chi cells in peripheral blood than wild-type mice after injury. Further, the expression levels of Vegfa164 were upregulated in intraocular Ly6Chi macrophages/monocytes of C3−/− mice, but not as much as in wild-type mice. Collectively, our data demonstrate that despite a more pronounced induction of systemic inflammation, inhibition of complement factor C3 suppresses CNV by decreasing the recruitment of inflammatory cells to the lesion.

The Anti-Inflammatory Effect of Ripasudil (K-115), a Rho Kinase (ROCK) Inhibitor, on Endotoxin-Induced Uveitis in Rats

Purpose To investigate the anti-inflammatory properties of ripasudil, a Rho kinase (ROCK) inhibitor, using endotoxin-induced uveitis (EIU) in rats. Methods Endotoxin-induced uveitis was induced by footpad injection of lipopolysaccharide (LPS). Ripasudil was administered intraperitoneally 1 hour before and after LPS injection. The aqueous humor was collected 24 hours after injection, and the infiltrating cells, protein concentration, and levels of monocyte chemotactic protein-1 (MCP-1) were determined. Infiltrating cells in the iris ciliary body (ICB) and adherent leukocytes in retinal vessels were evaluated. The mRNA levels of IL-1β, IL-6, TNF-α, and MCP-1 in the retina and ICB were determined. A mouse macrophage cell line, RAW264.7, was stimulated with LPS in the presence or absence of ripasudil, and the expression of MCP-1 and nuclear translocation of nuclear factor (NF)-κB was analyzed. Results Ripasudil significantly reduced infiltrating cells and protein exudation in the aqueous humor, as well as the number of infiltrating cells in the ICB and adherent leukocytes in retinal vessels in EIU. Additionally, the protein level of MCP-1 in the aqueous humor and mRNA levels of IL-1β, IL-6, TNF-α, MCP-1, and intercellular adhesion molecule-1 in the ICB and retina were suppressed by ripasudil. The production of MCP-1 and nuclear translocation of NF-κB in RAW264.7 cells were also suppressed by ripasudil. Conclusions The Rho/ROCK pathway plays a role in adhesion molecule expression and inflammatory cell infiltration in EIU, and ripasudil is a potent anti-inflammatory agent against ocular inflammatory diseases, including acute uveitis and possibly uveitic glaucoma.

Sphingosine-1-Phosphate (S1P)-Related Response of Human Conjunctival Fibroblasts After Filtration Surgery for Glaucoma

Purpose To investigate levels of sphingosine-1-phosphate (S1P) in aqueous fluid samples taken before and after filtration surgery and S1P-induced human conjunctival fibroblast (HCF) responses. Methods Levels of S1P and its related sphingophospholipids in aqueous fluid obtained immediately before and after filtration surgery were determined by liquid chromatography-tandem mass spectrometry. HCFs were used for all in vitro experiments. The expression of five S1P receptor subtypes in HCFs was examined by quantitative real-time PCR. The effect of S1P and receptor-specific antagonists on HCF viability and cell migration was assessed by WST-1 assay and scratch migration assay, respectively. Differentiation to myofibroblasts and extracellular matrix production was evaluated by examining changes in F-actin, α-smooth muscle actin (αSMA), and collagen expression with immunocytochemistry, Western blotting, and collagen accumulation assay, respectively. Results No significant S1P levels in the aqueous fluid samples were detectable immediately before surgery, but postoperative levels of several lysophospholipids, including S1P, dehydro-S1P, and sphingosine, were significantly increased to bioactive concentrations in aqueous fluid in the blebs (P < 0.0001). mRNA expression of the three main S1P receptor subtypes was detected in HCFs. Although S1P levels did not influence HCF proliferation, S1P enhanced cell migration, which could be inhibited by the S1P2 antagonist JTE 013. F-actin, αSMA, and collagen expression was significantly increased by S1P stimulation and was reduced by JTE 013. Conclusions Bioactive S1P concentrations were present in the aqueous fluid at the end of filtration surgery. S1P activated HCFs via S1P2 receptors. These results revealed the potential of S1P2 antagonists in preventing scarring after glaucoma filtration surgery.

Choroidal Neovascularization Is Inhibited in Splenic-Denervated or Splenectomized Mice with a Concomitant Decrease in Intraocular Macrophage

Purpose To determine the involvement of sympathetic activity in choroidal neovascularization (CNV) using laser-induced CNV in a mouse model. Methods We investigated changes in the proportions of intraocular lymphocytes, granulocytes, and three macrophage subtypes (Ly6Chi, Ly6Cint, and Ly6Clo) after laser injury in mice using flow cytometry, and evaluated CNV lesion size in mice lacking inflammatory cells. Further, we evaluated the lesion size in mice administered the β3 receptor antagonist, splenic-denervated and splenectomized mice. We also assessed changes in the proportions of intraocular macrophages and peripheral blood monocytes in splenic-denervated and splenectomized mice. Lastly, lesion size was compared between splenic-denervated mice with or without adoptive transfer of macrophages following laser injury. After Ly5.1 mice spleen-derived Ly6Chi cells were transferred into Ly5.2 mice, the proportions of intraocular Ly5.1+Ly6Chi cells were compared. Results In WT mice, the proportion of CD4+ T cells recruited into the eye increased progressively from day 3 to day 7 after laser injury, whereas, intraocular CD8+ T cells did not change significantly. Proportions of B220+ cells, granulocytes, and two subtypes of intraocular macrophages (Ly6Chi and Ly6Clo) peaked at day 3 following laser injury. In contrast, Ly6Cint/loCD64+ subtype showed a significantly higher percentage at day 7 after laser injury. There were no differences in lesion size between CD4–/–or Rag2–/–mice and controls, whereas lesion size was significantly reduced in CCR2−/− mice and clodronate liposome-treated mice. CNV lesion area was significantly reduced in mice with β3 blocker treatment, splenic-denervated and splenectomized mice compared with controls. Intraocular Ly6Chi macrophages were also reduced by splenic denervation or splenectomy. Adoptive transfer of spleen-derived Ly6Chi cells increased the lesion size in splenic-denervated mice. Compared with controls, intraocular donor-derived Ly6Chi cells recruited into the eye were reduced in splenic-denervated and splenectomized mice. Conclusions Although lymphocytes had little effect on CNV formation, Ly6Chi macrophages/monocytes exacerbated CNV in mice. Sympathetic activity might contribute to CNV via the recruitment of macrophages to the eye.