Naoya Ono

Amelioration of Collagen-Induced Arthritis by a Novel S1P1 Antagonist with Immunomodulatory Activities

Sphingosine 1-phosphate (S1P) regulates lymphocyte trafficking through the type 1 sphingosine 1-phosphate receptor (S1P1) and participates in many pathological conditions, including autoimmune diseases. We developed a novel S1P1-selective antagonist, TASP0277308, which is structurally unrelated to S1P. This antagonist competitively inhibited S1P-induced cellular responses, such as chemotaxis and receptor internalization. Furthermore, differing from previously reported S1P1 antagonists, TASP0277308 demonstrated in vivo activities to induce lymphopenia, a block in T cell egress from the thymus, displacement of marginal zone B cells, and upregulation of CD69 expression on both T and B cells, all of which recapitulate phenotypes of S1P1-deficient lymphocytes. In a mouse collagen-induced arthritis model, TASP0277308 significantly suppressed the development of arthritis, even after the onset of disease. These findings provide the first chemical evidence to our knowledge that S1P1 antagonism is responsible for immunosuppression in the treatment of autoimmune diseases and also resolve the discrepancies between genetic and chemical studies on the functions of S1P1 in lymphocytes.

20-hydroxyeicosatetraenoic acid (20-HETE): structural determinants for renal vasoconstriction.

The effects of natural and synthetic eicosanoids on the diameter of rat interlobular arteries studied in vitro were compared to that of the potent, endogenous vasoconstrictor 20-HETE. Vasoconstrictor activity was optimum for chain lengths of 20-22 carbons with at least one olefin or epoxide between located between C(13)-C(15) and an oxygen substituent at C(20)-C(22). The presence of delta (Zou et al. Am. J. Physiol. 1996, 270, R228; Gebremedhin, D. et al. Am. J. Physiol. 1998, 507, 771)-, delta (Carroll et al. Am. J. Physiol. 1996, 271, R863; Vazquez et al. Life Sci. 1995, 56, 1455)-, or delta (Imig et al. Hypertension 2000, 35, 307; Lopez et al. Amer. J. Physiol. 2001, 281, F420)-olefins had no influence on the vasoconstrictor response whereas the introduction of a C(7)-thiomethylene enhanced potency. A sulfonamide or alcohol, but not a lactone, could replace the C(1)-carboxylate. These data were used to construct a putative binding domain map of the 20-HETE receptor consisting of: (i) a comparatively open, hydrophilic binding site accommodating the C(1)-functionality; (ii) a hydrophobic trough spanning the olefins; (iii) a shallow pocket containing a critical pi-pi binding site in the vicinity of the pi (Ito et al. Am. J. Physiol. 1998, 274, F395; Quigley, R.; Baum, M.; Reddy, K. M.; Griener, J. C.; Falck, J. R. Am. J. Physiol. 2000, 278, F949)-olefin; and (iv) an oxyphilic binding site proximate to the omega-terminus.

Palladiurn(0)-catalysed transfer hydrogenation of alkynes to cis-alkenes with HCO2H–NEt3

Transfer hydrogenation of alkynes using HCO2H–NEt3 as a hydrogen donor in the presence of Pd0-catalyst proceeds highly stereoselecively to afford cis-alkenes in excellent yields, thus providing a practical method for conversion of alkynes to cis-alkenes.

A highly practical synthesis of natural PGE1, Δ2-trans-PGE1 and 2,2,3,3-tetradehydro-PGE1 via two-component coupling process using zinc-copper reagents

Abstract A highly practical synthesis of natural PGE 1 , Δ 2 -trans-PGE 1 and 2,2,3,3-tetradehydro-PGE 1 has been achieved in which the 1,4-addition reaction of the corresponding functionalized zinc-copper reagents to the enones 2 and/or 4 plays a key role.

Blocking S1P interaction with S1P1 receptor by a novel competitive S1P1-selective antagonist inhibits angiogenesis

Sphingosine 1-phosphate receptor type 1 (S1P(1)) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P(1) and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P(1)-selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P(1) antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P(1) is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

Synthesis and structure-activity relationships of a new class of selective EP3 receptor agonist, 13,14-didehydro-16-phenoxy analogues of prostaglandin E1.

A series of 13,14-didehydro-16-phenoxy analogues of prostaglandin E1 was synthesized and their agonistic activity on EP receptor subtypes was evaluated. 13,14-Didehydro-16-phenoxy-1-decarboxy analogues, 7e and 7f, display highly selective activity on the EP3 receptor subtype, thus, their utility as a selective anti-ulcer agent can be expected.

Design, synthesis, and evaluation of novel 4-thiazolylimidazoles as inhibitors of transforming growth factor-β type I receptor kinase.

A novel series of 4-thiazolylimidazoles was synthesized as transforming growth factor-β (TGF-β) type I receptor (also known as activin receptor-like kinase 5 or ALK5) inhibitors. These compounds were evaluated for their ALK5 inhibitory activity in an enzyme assay and their TGF-β-induced Smad2/3 phosphorylation inhibitory activity in a cell-based assay. N-{[5-(1,3-benzothiazol-6-yl)-4-(4-methyl-1,3-thiazol-2-yl)-1H-imidazol-2-yl]methyl}butanamide 20, a potent and selective ALK5 inhibitor, exhibited good enzyme inhibitory activity (IC(50)=8.2nM) as well as inhibitory activity against TGF-β-induced Smad2/3 phosphorylation at a cellular level (IC(50)=32nM).

A highly efficient approach to prostaglandins via radical addition of α side-chains to methylenecyclopentanones. Total synthesis of natural PGE1, limaprost and new prostaglandin derivatives.

Abstract Reaction of methylenecyclopentanones 2 with alkyl iodides via radical 1,4-addition pathway proceeds in good yields, thus providing an easy method for synthesis of not only known prostaglandins such as PGE 1 and Limafrost but also new prostaglandin derivatives.

5-(1,3-Benzothiazol-6-yl)-4-(4-methyl-1,3-thiazol-2-yl)-1H-imidazole derivatives as potent and selective transforming growth factor-β type I receptor inhibitors

A series of 5-(1,3-benzothiazol-6-yl)-4-(4-methyl-1,3-thiazol-2-yl)-1H-imidazole derivatives was synthesized as transforming growth factor-β (TGF-β) type I receptor (also known as activin-like kinase 5 or ALK5) inhibitors. These compounds were evaluated for their ALK5 inhibitory activity in an enzyme assay and for their TGF-β-induced Smad2/3 phosphorylation inhibitory activity in a cell-based assay. As a representative compound, 16i was a potent and selective ALK5 inhibitor, exhibiting a good enzyme inhibitory activity (IC(50) = 5.5 nM) as well as inhibitory activity against TGF-β-induced Smad2/3 phosphorylation at a cellular level (IC(50) = 36 nM). Furthermore, the topical application of 3% 16i lotion significantly inhibited Smad2 phosphorylation in Mouse skin (90% inhibition compared with vehicle-treated animals).

Synthesis of the key component for preparation of 6-ketoprostaglandins by a two-component coupling process: synthesis of 6-keto-prostaglandin E1, ornoprostil and Δ2-trans-6-ketoprostaglandin E1

Starting with commercially available (3S, 4R)-3-(methoxymethyloxy)-2-methylidene-4-siloxycyclopentanone 2, useful 6-keto-prostaglandin intermediates 1 have been prepared in good yields by a sequence of reactions which includes treatment with NaBr in the presence of BF3·OEt2, Pd-catalysed coupling of the resulting 2-bromomethyl-4-siloxycyclopent-2-enone 3 with the alkenylborane 4 or 9 and conversion of the alkenyl moiety into an epoxy and then into a keto group. The synthesis of 6-keto-PGE1, ornoprostil and Δ2-trans-6-keto-PGE1 by using 1 is also described.