Design, synthesis, and pharmacological evaluation of N-(3-carbamoyl-1H-pyrazol-4-yl)-1,3-oxazole-4-carboxamide derivatives as interleukin-1 receptor-associated kinase 4 inhibitors with reduced potential for cytochrome P450 1A2 induction.

Interleukin-1 receptor-associated kinase 4 (IRAK4) is a critical molecule in Toll-like receptor/interleukin-1 receptor signaling and an attractive therapeutic target for a wide range of inflammatory and autoimmune diseases as well as cancers. In our search for novel IRAK4 inhibitors, we conducted structural modification of a thiazolecarboxamide derivative 1, a lead compound derived from high-throughput screening hits, to elucidate structure-activity relationship and improve drug metabolism and pharmacokinetic (DMPK) properties. First, conversion of the thiazole ring of 1 to an oxazole ring along with introduction of a methyl group at the 2-position of the pyridine ring aimed at reducing cytochrome P450 (CYP) inhibition were conducted to afford 16. Next, modification of the alkyl substituent at the 1-position of the pyrazole ring of 16 aimed at improving CYP1A2 induction properties revealed that branched alkyl and analogous substituents such as isobutyl (18) and (oxolan-3-yl)methyl (21), as well as six-membered saturated heterocyclic groups such as oxan-4-yl (2), piperidin-4-yl (24, 25), and dioxothian-4-y (26), are effective for reducing induction potential. Representative compound AS2444697 (2) exhibited potent IRAK4 inhibitory activity with an IC50 value of 20 nM and favorable DMPK properties such as low risk of drug-drug interactions mediated by CYPs as well as excellent metabolic stability and oral bioavailability.

Patch esophagoplasty using an in-body-tissue-engineered collagenous connective tissue membrane.

AIM: Although many approaches to esophageal replacement have been investigated, these efforts have thus far only met limited success. In-body-tissue-engineered connective tissue tubes have been reported to be effective as vascular replacement grafts. The aim of this study was to investigate the usefulness of an In-body-tissue-engineered collagenous connective tissue membrane, "Biosheet", as a novel esophageal scaffold in a beagle model. METHODS: We prepared Biosheets by embedding specially designed molds into subcutaneous pouches in beagles. After 1-2months, the molds, which were filled with ingrown connective tissues, were harvested. Rectangular-shaped Biosheets (10×20mm) were then implanted to replace defects of the same size that had been created in the cervical esophagus of the beagle. An endoscopic evaluation was performed at 4 and 12weeks after implantation. The esophagus was harvested and subjected to a histological evaluation at 4 (n=2) and 12weeks (n=2) after implantation. The animal study protocols were approved by the National Cerebral and Cardiovascular Centre Research Institute Committee (No. 16048). RESULTS: The Biosheets showed sufficient strength and flexibility to replace the esophagus defect. All animals survived with full oral feeding during the study period. No anastomotic leakage was observed. An endoscopic study at 4 and 12weeks after implantation revealed that the anastomotic sites and the internal surface of the Biosheets were smooth, without stenosis. A histological analysis at 4weeks after implantation demonstrated that stratified squamous epithelium was regenerated on the internal surface of the Biosheets. A histological analysis at 12weeks after implantation showed the regeneration of muscle tissue in the implanted Biosheets. CONCLUSION: The long-term results of patch esophagoplasty using Biosheets showed regeneration of stratified squamous epithelium and muscular tissues in the implanted sheets. These results suggest that Biosheets may be useful as a novel esophageal scaffold.

Antinociceptive effects of AS1892802, a novel Rho kinase inhibitor, in rat models of inflammatory and noninflammatory arthritis.

Rho kinase (ROCK) is involved in various physiological functions, including cell motility, vasoconstriction, and neurite extension. Although a functional role of ROCK in nociception in the central nervous tissue has been reported in neuropathy, the peripheral function of this protein in hyperalgesia is not known. In this study, antinociceptive effects of AS1892802 [1-[(1S)-2-hydroxy-1-phenylethyl]-3-[4-(pyridin-4-yl)phenyl]urea], a novel and highly selective ROCK inhibitor, were investigated in two rat models of arthritis. Orally administered AS1892802 exhibited potent antinociceptive effect in both an adjuvant-induced arthritis (AIA) model (inflammatory arthritis model) and a monoiodoacetate-induced arthritis (MIA) model (noninflammatory arthritis model), with an ED(50) of 0.15 mg/kg (MIA model). Fasudil, a ROCK inhibitor, and tramadol were also effective in both models; however, diclofenac was effective only in the AIA model. The onset of antinociceptive effect of AS1892802 was as fast as those of tramadol and diclofenac. AS1892802 did not induce gastric irritation or abnormal behavior. Because AS1892802 rarely penetrates the central nervous tissue and is also effective by intra-articular administration, it seemed to function peripherally. These results suggest that AS1892802 has an attractive analgesic profile for the treatment of severe osteoarthritis pain.