Structure-guided discovery of potent and oral soluble epoxide hydrolase inhibitors for the treatment of neuropathic pain

Soluble epoxide hydrolase (sEH) is related to arachidonic acid cascade and is over-expressed in a variety of diseases, making sEH an attractive target for the treatment of pain as well as inflammatory-related diseases. A new series of memantyl urea derivatives as potent sEH inhibitors was obtained using our previous reported compound 4 as lead compound. A preferential modification of piperidinyl to 3-carbamoyl piperidinyl was identified for this series via structure-based rational drug design. Compound A20 exhibited moderate percentage plasma protein binding (88.6%) and better metabolic stability in vitro. After oral administration, the bioavailability of A20 was 28.6%. Acute toxicity test showed that A20 was well tolerated and there was no adverse event encountered at dose of 6.0 g/kg. Inhibitor A20 also displayed robust analgesic effect in vivo and dose-dependently attenuated neuropathic pain in rat model induced by spared nerve injury, which was better than gabapentin and sEH inhibitor (±)-EC-5026. In one word, the oral administration of A20 significantly alleviated pain and improved the health status of the rats, demonstrating that A20 was a promising candidate to be further evaluated for the treatment of neuropathic pain.

Runx2 is Involved in Regulating Osterix Promoter Activity and Gene Expression / 生物化学与生物物理进展

Though Runx2 and Osterix are both key transcription factors in the pathway of osteoblast differentiation, whether Runx2 positively regulates Osterix being unknown. It was showed that Runx2 induced the gene expression of Osterix both in the non-osteoblastic cell lines, either pluripotent or differentiated, and in the osteoblastic cell lines. At the same time, the results also indicated that Runx2 up-regulated the activity of the 3.2 kb human Osterix promoter. Further experiments identified a highly conserved and functional Runx2 binding site "AGTGGTT" within the promoter. Thus the results support the hypothesis that Runx2 is involved in the regulation of the Osterix gene expression. Moreover, the transient transfection and dual-luciferase assay showed Osterix up-regulated the activity of the 2.3 kb type Ⅰ collagen promoter in the non-osteoblastic cells, but Runx2 did not. This difference implies that Osterix, the down stream transcription factor of Runx2 during osteoblast differentiation, is needed to stimulate the osteoblast-specific gene expression of type Ⅰ collagen.