Inhibitory Effects of a Novel µ-Opioid Receptor Nonpeptide Antagonist, UD-030, on Morphine-Induced Conditioned Place Preference.

Although opioids are widely used to treat moderate to severe pain, opioid addiction and the opioid overdose epidemic are becoming more serious. Although opioid receptor antagonists/partial agonists, such as naltrexone and buprenorphine, have relatively low selectivity for the µ-opioid receptor (MOP), they have been used for the management of opioid use disorder. The utility of highly selective MOP antagonists remains to be evaluated. Here, we biologically and pharmacologically evaluated a novel nonpeptide ligand, UD-030, as a selective MOP antagonist. UD-030 had more than 100-fold higher binding affinity for the human MOP (Ki = 3.1 nM) than for δ-opioid, κ-opioid, and nociceptin receptors (Ki = 1800, 460, and 1800 nM, respectively) in competitive binding assays. The [35S]-GTPγS binding assay showed that UD-030 acts as a selective MOP full antagonist. The oral administration of UD-030 dose-dependently suppressed the acquisition and expression of morphine-induced conditioned place preference in C57BL/6J mice, and its effects were comparable to naltrexone. These results indicate the UD-030 may be a new candidate for the treatment of opioid use disorder, with characteristics that differ from traditional medications that are in clinical use.

Tetrahydropyridine derivatives with inhibitory activity on the production of proinflammatory cytokines: part 3.

In order to develop a new class of anti-rheumatic drug which inhibits production of proinflammatory cytokines such as TNFalpha, IL-1beta, IL-6, and IL-8, a series of 3-pyridylpyrrole derivatives possessing a bicyclic tetrahydropyridine moiety at the 4-position of the pyrrole ring were synthesized and their pharmacological activities were evaluated. The derivatives were found to have potent inhibitory activities on the production of the cytokines both in vitro and in vivo. Among them, compound 4a, (S)-2-(4-fluorophenyl)-4-(1,2,3,5,6,8a-hexahydroindolizin-7-yl)-3-(pyridin-4-yl)-1H-pyrrole (R-132811), achieved the most promising results in various in vitro and in vivo tests including several rheumatoid arthritis models ((i) inhibition of p38alpha, p38beta, p38gamma, and p38delta MAP kinases: IC(50)=0.034, 0.572, >10, and >10 microM, respectively; (ii) inhibition of TNFalpha, IL-1beta, IL-6, and IL-8 production in human whole blood: IC(50)=0.026, 0.020, 0.88, and 0.016 microM, respectively; (iii) inhibition of LPS induced TNFalpha, IL-1beta and IL-6 production in mice: ID(50)=0.93, 8.63, and 0.11 mg/kg, p.o., respectively; (iv) inhibition of anti-collagen antibody-induced arthritis in mice: ID(50)=2.22 mg/kg, p.o.; (v) inhibition of collagen-induced arthritis in mice: ID(50)=2.38 mg/kg, p.o.; (vi) prophylactic effect on adjuvant-induced arthritis in rats: ID(50)=3.1 mg/kg, p.o.; (vii) therapeutic effect on adjuvant-induced arthritis in rats: ID(50)=4.9 mg/kg, p.o.; (viii) analgesic effect on adjuvant-induced arthritic pain in rats: ID(50)=2.9 mg/kg, p.o.). As a result, compound 4a was chosen as a candidate for further pre-clinical studies.

Tetrahydropyridine derivatives with inhibitory activity on the production of proinflammatory cytokines: part 2.

We previously reported a novel pyrrole derivative 1 which possesses a tetrahydropyridine group at the beta-position with a proinflammatory cytokine TNFalpha production inhibitor. Herein, we report the synthesis and biological activity of N- and alpha-position substituted tetrahydropyridine derivatives. In this series, we found that compound 3o showed good inhibitory activity in vitro (inhibition of lipopolysaccharide (LPS)-induced TNFalpha production in human whole blood, IC(50)=0.44 microM) and compound 3i demonstrated potent inhibitory activity in vivo (inhibition of LPS-induced TNFalpha production in mice, ID(50)=1.42 mg/kg).

Tetrahydropyridine derivatives with inhibitory activity on the production of proinflammatory cytokines: part 1.

We investigated proinflammatory cytokine TNFalpha production inhibitors in order to develop novel anti-inflammatory agents. According to the results, we found that 17, a pyrrole derivative possessing a tetrahydropyridine group at the beta-position, showed potent inhibitory activity in vitro (inhibition of lipopolysaccharide (LPS) induced TNFalpha production in human whole blood, IC(50)=1.86 microM) and in vivo (inhibition of LPS induced TNFalpha production in mice, ID(50)=5.98 mg/kg).

Preclinical pharmacology profile of CS-706, a novel cyclooxygenase-2 selective inhibitor, with potent antinociceptive and anti-inflammatory effects.

We report here the preclinical anti-inflammatory profile of CS-706 [2-(4-ethoxyphenyl)-4-methyl-1-(4-sulfamoylphenyl)-1H-pyrrole], a novel cyclooxygenase-2 (COX-2) selective inhibitor. CS-706 selectively inhibited COX-2 in a human whole blood assay with an IC(50) of 0.31 microM, compared with an IC(50) of 2.2 microM for COX-1. The selectivity ratio of CS-706 was higher than those of the conventional non-steroidal anti-inflammatory drugs naproxen, indomethacin, and Diclofenac-Na, whereas it was lower than those of rofecoxib, valdecoxib and etoricoxib. It was similar to that of celecoxib. The pharmacokinetic profile of CS-706 showed rapid absorption and dose-proportional exposure after oral administration to rats. CS-706 inhibited prostaglandin E(2) production in inflamed tissue induced by yeast-injection in rats with potency similar to that of indomethacin. However, it inhibited gastric mucosal prostaglandin E(2) production in normal rats weakly compared with indomethacin. CS-706 ameliorated both yeast-induced inflammatory acute pain (ED(50)=0.0090 mg/kg) and adjuvant-induced chronic arthritic pain (ED(50)=0.30 mg/kg) in rats. CS-706 showed more potent antinociceptive activity than celecoxib and rofecoxib in these models. In an adjuvant-induced arthritic model in rats, CS-706 suppressed foot swelling prophylactically with an ID(50) of 0.10 mg/kg/day, and decreased foot swelling in the established arthritis therapeutically in a dose range of 0.040 to 1.0 mg/kg/day. Single administration of up to 100 mg/kg of CS-706 induced no significant gastric lesions in rats. In conclusion, CS-706 is a COX-2-selective inhibitor with a potent antinociceptive and anti-inflammatory activity and a gastric safety profile.

Novel p38 mitogen-activated protein kinase inhibitor R-130823 protects cartilage by down-regulating matrix metalloproteinase-1,-13 and prostaglandin E2 production in human chondrocytes.

In order to study the involvement of mitogen-activated protein kinase p38 in osteoarthritis, we investigated the effect of novel p38 inhibitor R-130823 {2-(4-fluorophenyl)-4-(1-phenethyl-1,2,3,6-tetrahydropyridin-4-yl)-3-(pyridin-4-yl)-1H-pyrrole} on human chondrocytes and bovine cartilage. In human primary chondrocytes, the production of matrix metalloproteinase-13 and -1 (MMP-13 and -1) and prostaglandin E2 (PGE2) was induced by interleukin-1beta. Pretreatment with R-130823 inhibited the release of MMP-13, MMP-1 and PGE2 with IC50 values of 20, 230 and 3.9 nM, respectively. The inhibitory activity was also confirmed by a decrease in MMP-13 release from human chondrosarcoma cell line SW1353 with an IC50 value of 17 nM. Ribonuclease protection assay on human primary chondrocytes indicated that MMP-13 and MMP-1 mRNA levels almost reached the maximum 14 h after IL-1 stimulation, while cyclooxygenase-2 (COX-2) mRNA quickly reached the maximum 4 h after the stimulation. R-130823 down-regulated the steady-state levels of MMP-13 and MMP-1 mRNA with IC50 values of 4.2 and 79 nM, respectively. The COX-2 mRNA level was also suppressed with an IC50 value of 21 nM. In the explant culture of bovine nasal cartilage, R-130823 suppressed the collagen cleavage induced by interleukin-1alpha and oncostatin M, but not IL-1beta-mediated glycosaminoglycan release. These results suggest that activated p38 accelerates cartilage breakdown by enhancing the expression of MMPs responsible for collagen cleavage, which thus implies chondroprotective effects of p38 inhibitors in osteoarthritis.

Novel p38 MAP kinase inhibitor R-130823 suppresses IL-6, IL-8 and MMP-13 production in spheroid culture of human synovial sarcoma cell line SW 982.

Synovial hyperplasia is a hallmark of rheumatoid arthritis (RA) and is regarded as a major destructive element of articular bone and cartilage. This pathological process is accompanied by the production of proinflammatory cytokines, prostaglandin E(2) (PGE(2)), and matrix metalloproteinases (MMPs) in synoviocytes. We studied the spontaneous production of these substances in RA synoviocytes in spheroid culture. Synovial sarcoma cell line SW 982 formed a single spheroid in non-adherent culture plates. It produced interleukin (IL)-1beta, IL-6, IL-8, PGE(2), MMP-2 and MMP-13. Neither the addition of integrin antagonizing oligopeptide (GRGDSP) nor that of vitronectin receptor inhibitor SB-265123 to the culture inhibited any production. Phosphorylation of p38 mitogen-activated protein (MAP) kinase was observed during the culture. A novel p38 MAP kinase inhibitor, R-130823, inhibited the release of IL-6, IL-8 and MMP-13 in a concentration-dependent manner, but not that of IL-1beta or MMP-2. Real-time RT-PCR analysis demonstrated that IL-6, IL-8 and MMP-13 were inhibited at the transcriptional level. R-130823 did not affect the production of PGE(2) in spheroid culture, while the addition of R-130823 suppressed IL-1beta-induced PGE(2) synthesis in monolayer culture of SW 982 cells. The results suggest that spheroid culture induced proinflammatory factors and MMPs in signaling pathways both dependent and independent of p38 MAP kinase.

R-130823, a novel inhibitor of p38 MAPK, ameliorates hyperalgesia and swelling in arthritis models.

We found that a novel compound, R-130823 {2-(4-fluorophenyl)-4-(1-phenethyl-1,2,3,6-tetrahydropyridin-4-yl)-3-(pyridin-4-yl)-1H-pyrrole}, had highly selective inhibition against mitogen-activated protein kinase p38alpha (IC50=22 nM). The release of tumor necrosis factor-alpha, interleukin-1beta, -6 and -8 was inhibited in lipopolysaccharide-stimulated human blood pretreated by R-130823, with IC50 values of 0.089, 0.066, 0.95 and 0.16 microM, respectively. R-130823 reduced the established hind paw swelling in rat adjuvant-induced arthritis, while methotrexate showed no suppression. In the same model, R-130823 ameliorated adjuvant-induced hyperalgesia with rapid onset and long duration comparable to a cyclooxygenase-2 inhibitor, celecoxib. In murine collagen-induced arthritis, R-130823 blocked the progress of arthritis when administered just after the onset of the arthritis. Histological analysis of the knee joints showed that proliferation of fibroblasts and synoviocytes and infiltration of neutrophils were ameliorated. In conclusion, R-130823 is expected to be an efficacious treatment for rheumatoid arthritis by blocking the p38 pathway.