Colchicine-derived compound CT20126 promotes skin allograft survival by regulating the balance of Th1 and Th2 cytokine production

Colchicine has been shown to regulate the expression of inflammatory gene, but this compound possesses much weaker anti-inflammatory activity. In this study, we synthesized a new colchicine derivative CT20126 and examined its immunomodulatory property. CT20126 was found to have immunosuppressive effects by inhibiting lymphocyte proliferation without cytotoxicity and effectively inhibit the transcriptional expression of the inflammatory genes, iNOS, TNF-alpha, and IL-1beta, in macrophages stimulated by LPS. This effect was nearly comparable to that of cyclosporine A. This compound also significantly suppressed the production of nitric oxide and Th1-related pro-inflammatory cytokines, IL-1beta, TNF-alpha, and IL-2, with minimal suppression of Th2-related anti-inflammatory cytokines IL-4 and IL-10 in the sponge matrix allograft model. Moreover, administration of CT20126 prolonged the survival of allograft skins from BALB/c mice (H-2d) to the dorsum of C57BL/6 (H-2b) mice. The in vivo immune suppressive effects of CT20126 were similar to that of cyclosporine A. These results indicate that this compound may have potential therapeutic value for transplantation rejection and other inflammatory diseases.

Prostaglandin E2 stimulates angiogenesis by activating the nitric oxide/cGMP pathway in human umbilical vein endothelial cells

Prostaglandin E2(PGE2), a major product of cyclooxygenase, has been implicated in modulating angiogenesis, vascular function, and inflammatory processes, but the underlying mechanism is not clearly elucidated. We here investigated the molecular mechanism by which PGE 2 regulates angiogenesis. Treatment of human umbilical vein endothelial cells (HUVEC) with PGE 2 increased angiogenesis. PGE 2 increased phosphorylation of Akt and endothelial nitric oxide synthase (eNOS), eNOS activity, and nitric oxide (NO) production by the activation of cAMP-dependent protein kinase (PKA) and phosphatidylinositol 3-kinase (PI3K). Dibutyryl cAMP (DB-cAMP) mimicked the role of PGE 2 in angiogenesis and the signaling pathway, suggesting that cAMP is a down-stream mediator of PGE 2. Furthermore, PGE 2 increased endothelial cell sprouting from normal murine aortic segments, but not from eNOS-deficient ones, on Matrigel. The angiogenic effects of PGE 2 were inhibited by the inhibitors of PKA, PI3K, eNOS, and soluble guanylate cyclase, but not by phospholipase C inhibitor. These results clearly show that PGE 2 increased angiogenesis by activating the NO/cGMP signaling pathway through PKA/PI3K/Akt-dependent increase in eNOS activity.