Downregulation of COL12A1 and COL13A1 by a selective EP2 receptor agonist, omidenepag, in human trabecular meshwork cells.

Omidenepag isopropyl (OMDI) is an intraocular pressure (IOP)-lowering drug used to treat glaucoma. The active form of OMDI, omidenepag (OMD), lowers elevated IOP, the main risk factor for glaucoma, by increasing the aqueous humor outflow; however, a detailed understanding of this mechanism is lacking. To clarify the IOP-lowering mechanism of OMDI, the effects of OMD on the mRNA expression of the extracellular matrix, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs) were evaluated in human trabecular meshwork cells. Under 2D culture conditions, the mRNA expression of FN1, COL1A1, COL1A2, COL12A1, and COL13A1 decreased in a concentration-dependent manner after 6 or 24 h treatment with 10 nM, 100 nM, and 1 µM OMD, while that of COL18A1 decreased after 6 h treatment with 1 µM OMD. Significant changes in expression were observed for many MMP and TIMP genes. Under 3D culture conditions, the extracellular matrix-related genes COL12A1 and COL13A1 were downregulated by OMD treatment at all three concentrations. Under both 2D and 3D culture conditions, COL12A1 and COL13A1 were downregulated following OMD treatment. Reduction in the extracellular matrix contributes to the decrease in outflow resistance, suggesting that the downregulation of the two related genes may be one of the factors influencing the IOP-lowering effect of OMDI. Our findings provide insights for the use of OMDI in clinical practice.

Additive Intraocular Pressure-Lowering Effects of a Novel Selective EP2 Receptor Agonist, Omidenepag Isopropyl, Combined with Existing Antiglaucoma Agents in Conscious Ocular Normotensive Monkeys.

Purpose: To investigate the intraocular pressure (IOP)-lowering effects of omidenepag isopropyl (OMDI), a potent and highly selective prostanoid EP2 receptor agonist, as a potential first-line ocular hypotensive agent when combined with existing antiglaucoma agents in conscious ocular normotensive monkeys. Methods: Male cynomolgus monkeys were examined under conscious conditions. OMDI ophthalmic solution alone was topically applied to an eye or combined with other ophthalmic solutions at 5-min intervals. The contralateral eye was left untreated. IOP was measured before and at 2, 4, 6, and 8 h after instillation. Results: Topical application of OMDI to the eye resulted in statistically significant IOP reduction, which lasted for at least 6 h. The IOP-lowering effects of OMDI concomitantly administered with any of the tested antiglaucoma agents (timolol, brinzolamide, netarsudil, ripasudil, and brimonidine) were greater than those of OMDI alone. Furthermore, these enhanced IOP responses to their concomitant use were statistically significant compared with those of the tested antiglaucoma agents alone. Any combination of OMDI with the tested agents did not lead to serious abnormalities either systemically or locally in the eye. Conclusions: We demonstrated that OMDI has additive IOP-lowering effects when administered in combination with various antiglaucoma agents, namely, ß-adrenergic antagonist, carbonic anhydrase inhibitor, Rho-associated coiled-coil containing protein kinase inhibitors, and α2-adrenergic agonist. These results suggest that OMDI provides additional clinical benefits because of its unique mechanisms of action when combination therapy is required.

The Antiglaucoma Agent and EP2 Receptor Agonist Omidenepag Does Not Affect Eyelash Growth in Mice.

Purpose: The present study investigated the effects of the antiglaucoma agent and selective E2 receptor agonist omidenepag isopropyl (OMDI) on eyelash growth in comparison with a prostaglandin analog (prostamide receptor agonist) in mice. Methods: Four-week-old female mice (C57BL/6J) were divided into 3 groups of n = 10 each. The groups were administered 3 µL of 0.003% OMDI solution, the vehicle (negative control), or a 0.03% bimatoprost solution (positive control) on the upper eyelids of the right eyes once daily for 14 days. On the 15th day, all animals were euthanized, and the upper eyelids with eyelashes were fixed with 10% neutral formalin. Eyelashes were evaluated for number, length, and thickness using a stereomicroscope. Specimens were then paraffin-embedded and stained with hematoxylin and eosin, followed by microscopic examination to assess eyelash morphology and growth cycle. Results: Eyelash number (143.5 ± 6.7/eyelid), thickness, and percentage of dermal papilla in the anagen phase in the OMDI group were similar to those observed in the vehicle group (eyelash number, 144.2 ± 5.7/eyelid). In contrast, eyelash number (166.7 ± 7.0/eyelid), thickness, and the percentage of dermal papilla in the anagen phase were significantly greater in the bimatoprost group compared with those of the vehicle group. Conclusions: Unlike existing prostaglandin analogs, our findings indicate that OMDI has no effect on eyelash growth in mice, suggesting that it may be a promising antiglaucoma agent with a reduced number of adverse effects.

Effects of the Selective EP2 Receptor Agonist Omidenepag on Adipocyte Differentiation in 3T3-L1 Cells.

Purpose: We aimed at comparing the effects of omidenepag (OMD) with those of prostaglandin F (FP) receptor agonists (FP agonists) on adipogenesis in mouse 3T3-L1 cells. Methods: To evaluate the agonistic activities of OMD against the mouse EP2 (mEP2) receptor, we determined cAMP contents in mEP2 receptor-expressing CHO cells by using radioimmunoassays. Overall, 3T3-L1 cells were cultured in differentiation medium for 10 days and adipocyte differentiation was assessed according to Oil Red O-stained cell areas. Changes in expression levels of the adipogenic transcription factors Pparg, Cebpa, and Cebpb were determined by using real-time polymerase chain reaction (PCR). OMD at 0.1, 1, 10, and 40 µmol/L, latanoprost free acid (LAT-A) at 0.1 µmol/L, or prostaglandin F2α (PGF2α), at 0.1 µmol/L were added to cell culture media during adipogenesis. Oil Red O-stained areas and expression patterns of transcription factor targets of OMD or FP agonists were compared with those of untreated controls. Results: The 50% effective concentration (EC50) of OMD against the mEP2 receptor was 3.9 nmol/L. Accumulations of Oil Red O-stained lipid droplets were observed inside control cells on day 10. LAT-A and PGF2α significantly inhibited the accumulation of lipid droplets; however, OMD had no effect on this process even at concentrations up to 40 µmol/L. LAT-A and PGF2α significantly suppressed Pparg, Cebpa, and Cebpb gene expression levels during adipocyte differentiation. Conversely, OMD had no obvious effects on the expression levels of these genes. Conclusions: A selective EP2 receptor agonist, OMD, did not affect the adipocyte differentiation in 3T3-L1 cells, whereas FP agonists significantly inhibited this process.

Imaging of the Mouse Lymphatic Sinus during Early Stage Lymph Node Metastasis Using Intranodal Lymphangiography with X-ray Micro-computed Tomography.

PURPOSE: Lymph node (LN) metastasis is detected prior to distant metastasis in many types of cancer. Detecting early stage LN metastasis can improve treatment outcomes. However, there are few clinical imaging modalities capable of diagnosing metastatic LNs of clinical N0 status (i.e., before their volume increases) with high precision. Here, we report a new method for diagnosing metastatic LNs of clinical N0 status in a mouse model of LN metastasis. PROCEDURES: The method involved using intranodal lymphangiography with x-ray micro-computed tomography (micro-CT). Contrast agent was injected into an upstream LN to deliver it to a downstream LN, which was then removed and analyzed by micro-CT. RESULTS: We found that using an intranodal injection rate of 10-60 µl/min filled the lymphatic sinus of the downstream LN with contrast agent, although the accumulation of contrast agent in the upstream LN increased with a faster injection rate. Furthermore, breast cancer cells growing in the lymphatic sinus of the downstream LN (which was of clinical N0 status) impeded the flow of contrast agent from the upstream LN, resulting in areas deficient of contrast agent in the metastatic downstream LN. The formation of defect areas in the downstream LN manifested as a difference in position between the centroid of the entire LN area and the centroid of the region that filled with contrast agent. CONCLUSION: The present study indicates that intranodal lymphangiography with micro-CT has the potential to be used as a new method for diagnosing metastatic LNs of clinical N0 status.

Effects of a Novel Selective EP2 Receptor Agonist, Omidenepag Isopropyl, on Aqueous Humor Dynamics in Laser-Induced Ocular Hypertensive Monkeys.

PURPOSE: To investigate the mechanism of the intraocular pressure (IOP)-lowering effect of a novel selective prostaglandin E2 receptor 2 (EP2) receptor agonist, omidenepag isopropyl (OMDI). METHODS: The effect of OMDI on IOP and aqueous humor dynamics was evaluated in cynomolgus monkeys with unilateral laser-induced ocular hypertension. In a crossover manner, the hypertensive eye of each monkey was dosed once daily with 20 µL of either 0.002% OMDI or vehicle. On day 7 of dosing, IOP was measured by pneumatonometry, aqueous humor flow and outflow facility were evaluated by fluorophotometry, and uveoscleral outflow was calculated mathematically. Treatments were compared by paired t-tests. RESULTS: OMDI at 0.002% significantly lowered IOP by 27%, 35%, and 44% at 0.5, 1.5, and 4 h after the last dosing, respectively. There was no difference in aqueous humor flow between vehicle and OMDI treatments. When comparing OMDI to the vehicle treatment, outflow facility and uveoscleral outflow were significantly (P < 0.05) increased by 71% and 176%, respectively. CONCLUSIONS: OMDI, a novel IOP-lowering compound, reduced IOP by increasing outflow facility and uveoscleral outflow in nonhuman primates.

Identification of a Selective, Non-Prostanoid EP2 Receptor Agonist for the Treatment of Glaucoma: Omidenepag and its Prodrug Omidenepag Isopropyl.

EP2 receptor agonists are expected to be effective ocular hypotensive agents; however, it has been suggested that agonism to other EP receptor subtypes may lead to undesirable effects. Through medicinal chemistry efforts, we identified a scaffold bearing a (pyridin-2-ylamino)acetic acid moiety as a promising EP2-selective receptor agonist. (6-((4-(Pyrazol-1-yl)benzyl)(pyridin-3-ylsulfonyl)aminomethyl)pyridin-2-ylamino)acetic acid 13ax (omidenepag, OMD) exerted potent and selective activity toward the human EP2 receptor (h-EP2). Low doses of omidenepag isopropyl (OMDI), a prodrug of 13ax, lowered intraocular pressure (IOP) in ocular normotensive monkeys. OMDI was selected as a clinical candidate for the treatment of glaucoma.

Pharmacologic Characterization of Omidenepag Isopropyl, a Novel Selective EP2 Receptor Agonist, as an Ocular Hypotensive Agent.

Purpose: The objective of this study was to investigate the pharmacologic characteristics of omidenepag isopropyl (OMDI), a compound developed as a novel intraocular pressure (IOP)-lowering agent, with better IOP control and fewer side effects than other prostanoid receptor agonists such as prostaglandin F receptor (FP) agonists. Methods: Binding activities of OMDI and its hydrolyzed form, omidenepag (OMD), to human recombinant prostanoid receptors (DP1-2, EP1-4, FP, and IP) were evaluated. Based on these binding assays, the agonistic activities of OMDI and OMD were further evaluated using cultured cells expressing selected prostanoid receptors. The pharmacokinetics of OMDI after topical administration was assessed in rabbits by measurement of the concentrations of both OMDI and OMD in aqueous humor. The ocular hypotensive effect of OMDI was evaluated in ocular normotensive rabbits, dogs, and both ocular normotensive and hypertensive monkeys. Results: OMD was determined to be a selective EP2 receptor agonist. OMDI weakly bound to EP1; however, the agonistic activity of OMDI to this receptor was not demonstrated in the functional assay. After topical administration of OMDI, OMD was detected in aqueous humor whereas OMDI was not detectable. OMDI significantly lowered IOP in both ocular normotensive and hypertensive animals. The significant ocular hypotensive effects of OMDI were demonstrated by both single and repeated dosing, and its effective duration suggests sufficient efficacy by once-daily dosing. Conclusions: These studies demonstrated that OMDI is hydrolyzed in the eye to OMD, an EP2 receptor agonist, with a significant ocular hypotensive effect in both ocular normotensive and hypertensive animal models.