Background and Purpose: The prostamides (prostaglandin-ethanolamides) and prostaglandin (PG) glyceryl esters are biosynthesized by COX-2 from the respective endocannabinoids anandamide and 2-arachidonyl glycerol. Agonist studies suggest that their pharmacologies are unique and unrelated to prostanoid receptors. This concept was further investigated using antagonists. Experimental Approach: The isolated feline iris was used as a key preparation, where prostanoid FP receptors and prostamide activity co-exist. Activity at human recombinant FP and other prostanoid receptors was determined using stable transfectants.
EP4-selective agonist may prevent indomethacin-induced gastric lesions and promote healing of existing and indomethacin-aggravated gastric ulcers, via promoting proliferation and survival of mucous epithelial cells.
Prostanoids are an important class of intraocular pressure (IOP)-lowering antiglaucoma agents that act primarily via increased uveo-scleral aqueous humor outflow through the ciliary body. We have developed two novel PGE(2) analogs that are specific agonists for the PGE(2) receptor subtypes EP2 and EP4, respectively. To identify gene regulatory networks and key players that mediate the physiological effects observed in vivo, we performed genomewide expression studies using human ciliary smooth muscle cells. Quantitative real-time RT-PCR confirmed a largely overlapping gene expression profile subsequent to EP2 and EP4 agonist treatment, with 65 significantly regulated genes identified overall, 5 being specific for the EP2 agonist and 6 specific for the EP4 agonist. We found predicted functional cAMP-response elements in promoter regions of a large fraction of the predominantly upregulated genes, which suggests that the cAMP signaling pathway is the most important intracellular signaling pathway for these agonists in these cells. Several target genes were identified that, as part of complex regulatory networks, are implicated in tissue remodeling processes and osmoregulation (e.g., AREG, LOXL3, BMP2, AQP3) and thus may help elucidate the mechanism of action of these IOP-lowering drugs involving the uveo-scleral outflow path.
Prodrugs of 5-aminosalicylic acid (5-ASA), such as sulfasalazine, have been the mainstay for the treatment and maintenance of inflammatory bowel disease (IBD) for decades, which is attributable to their antiadaptive immune activity. However, 5-ASA compromises regeneration of intestinal epithelia and induces apoptosis. The majority of patients eventually undergo colectomy. Agonists for the prostaglandin E 2 subtype 4 (EP4) receptor have been shown to protect epithelial barrier against colitis-inducing agents and could be valuable alternatives for sulfasalazine. Here, we compared sulfasalazine and a novel EP4 agonist for their abilities to prevent colitis induction and relieve symptoms of established colitis in a dextran sulfate sodium-indomethacin mouse model. The EP4 agonist dosedependently alleviated weight loss in colitis mice. Compared with sulfasalazine at 100 mg/kg on the colitis induction model, the EP4 agonist at 0.2 mg/kg was superior in reducing colitis symptoms, preventing increase of innate immune cells, and ameliorating inflammation in colon. In mice with established colitis, sulfasalazine quickly reversed weight loss but with fading efficacy. The EP4 agonist, in contrast, had slow but sustained effects on body weight gain and was more efficacious in epithelial regeneration. Such temporal differences between sulfasalazine and the EP4 agonist actions seemingly led to no additive effect in combination therapy. In conclusion, the EP4 agonist would be more efficacious in the maintenance of remission because of both anti-innate immune responses and epithelial regeneration activity, whereas sulfasalazine would be more suitable for induction of remission because of its rapid onset of antiadaptive inflammation action.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.