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.

Purpose. To establish a mouse model for the pharmacological analysis of antiglaucoma drugs, considering the effect of variations in IOP during 24 hours on the drugs’ effects, and to evaluate the effect of a newly developed FP agonist, tafluprost, on mouse IOP, in comparison with three clinically available prostaglandin (PG) analogues. methods. Inbred adult ddY mice were bred and acclimatized under a 12-hour light–dark cycle. With mice under general anesthesia, a microneedle method was used to measure IOP. A single drop of 3 μL of either drug or vehicle solution was topically applied once into one eye in each mouse, in a blinded manner, with the contralateral, untreated eye serving as the control. IOP reduction was evaluated by the difference in IOP between the treated and untreated eyes in the same mouse. First, to determine the period feasible for demonstrating a larger magnitude of ocular hypotensive effect, the 24-hour diurnal variation in mouse IOP was measured, and 0.005% latanoprost was applied at the peak or trough time of variation in 24-hour IOP. The time point of the most hypotensive effect was selected for further studies, to evaluate the effects of PG analogues. Second, mice received tafluprost (0.0003%, 0.0015%, 0.005%, or 0.015%), latanoprost (0.001%, 0.0025%, or 0.005%), travoprost (0.001%, 0.002%, or 0.004%), or isopropyl unoprostone (0.03%, 0.06%, or 0.12%), and each corresponding vehicle solution. IOP was then measured at 1, 2, 3, 6, 9, and 12 hours after drug administration. The ocular hypotensive effects of the other three PG analogues were compared with that of tafluprost. All experiments were conducted in a masked study design. results. The IOP in the untreated mouse eye was higher at night than during the day. Latanoprost significantly lowered IOP at night (21.4%), compared with the IOP in the untreated contralateral eye 2 hours after administration. The maximum IOP reduction was 20.2% ± 2.0%, 18.7% ± 2.5%, and 11.2% ± 1.8% of that in the untreated eye 2 hours after administration of 0.005% tafluprost, 0.005% latanoprost, and 0.12% isopropyl unoprostone, respectively, whereas it was 20.8% ± 4.6% at 6 hours with 0.004% travoprost (n = 7∼17). The order of ocular hypotensive effects of three clinically used PG analogues in mice was comparable to that in humans. Area under the curve (AUC) analysis revealed dose-dependent IOP reductions for each PG analogue. Tafluprost 0.005% decreased IOP more than 0.005% latanoprost at 3, 6, and 9 hours (P = 0.001–0.027) or 0.12% unoprostone at 2, 3, and 6 hours (P = 0.0004–0.01). conclusions. The 24-hour variation in mouse eyes should be taken into consideration when evaluating the reduction of IOP. The mouse model was found to be useful in evaluating the pharmacological response to PG analogues. A newly developed FP agonist, 0.005% tafluprost, lowered normal mouse IOP more effectively than did 0.005% latanoprost.

Purpose: To compare the levels of autotaxin (ATX), lysophosphatidic acid (LPA), and lysophosphatidylcholine (LPC) in the aqueous humor (AH) of healthy control subjects with those of patients with different subtypes of glaucoma, and also to investigate the relationship of the ATX–LPA pathway with IOP and subtype of glaucoma. Methods: This study included 164 eyes of 164 consecutive cases of cataract and glaucoma surgery (37 healthy, 31 normal tension glaucoma, 49 primary open angle glaucoma, 28 secondary open angle glaucoma, and 19 exfoliation glaucoma). Aqueous levels of LPA, LPC, and ATX were quantified using liquid chromatography-tandem mass spectrometry and a two-site immunoenzymetric assay. The association between aqueous levels of ATX/LPA/LPC and IOP elevation in different glaucoma subtypes was investigated. The diagnostic values of indices of the ATX–LPA pathway were compared using receiver operating characteristic curve analysis. Results: Notable increases in ATX/LPA/LPC levels in glaucoma patients were observed. The ATX–LPA pathway was significantly related to IOP elevation and the subtype of glaucoma, especially in SOAG and XFG patients, and the area under the curve was significant for discriminating glaucoma eyes from healthy eyes. Conclusions: Bioactive ATX/LPA/LPC concentrations were present in aqueous humor, and higher ATX and LPA concentrations were significantly correlated with IOP in all study subjects. Furthermore, the ATX–LPA pathway was significantly related to glaucoma subtype. These results reveal the potentially important role of the ATX–LPA pathway for IOP regulation in healthy subjects and glaucoma patients.

Glutathione peroxidase 4 (GPx4) is known for its unique function in the direct detoxification of lipid peroxides in the cell membrane and as a key regulator of ferroptosis, a form of lipid peroxidation–induced nonapoptotic cell death. However, the cytosolic isoform of GPx4 is considered to play a major role in inhibiting ferroptosis in somatic cells, whereas the roles of the mitochondrial isoform of GPx4 (mGPx4) in cell survival are not yet clear. In the present study, we found that mGPx4 KO mice exhibit a cone–rod dystrophy-like phenotype in which loss of cone photoreceptors precedes loss of rod photoreceptors. Specifically, in mGPx4 KO mice, cone photoreceptors disappeared prior to their maturation, whereas rod photoreceptors persisted through maturation but gradually degenerated afterward. Mechanistically, we demonstrated that vitamin E supplementation significantly ameliorated photoreceptor loss in these mice. Furthermore, LC–MS showed a significant increase in peroxidized phosphatidylethanolamine esterified with docosahexaenoic acid in the retina of mGPx4 KO mice. We also observed shrunken and uniformly condensed nuclei as well as caspase-3 activation in mGPx4 KO photoreceptors, suggesting that apoptosis was prevalent. Taken together, our findings indicate that mGPx4 is essential for the maturation of cone photoreceptors but not for the maturation of rod photoreceptors, although it is still critical for the survival of rod photoreceptors after maturation. In conclusion, we reveal novel functions of mGPx4 in supporting development and survival of photoreceptors in vivo.