Simon D.P. Baugh

Inhibition of Sphingosine-1-Phosphate Lyase for the Treatment of Autoimmune Disorders

During nearly a decade of research dedicated to the study of sphingosine signaling pathways, we identified sphingosine-1-phosphate lyase (S1PL) as a drug target for the treatment of autoimmune disorders. S1PL catalyzes the irreversible decomposition of sphingosine-1-phosphate (S1P) by a retro-aldol fragmentation that yields hexadecanaldehyde and phosphoethanolamine. Genetic models demonstrated that mice expressing reduced S1PL activity had decreased numbers of circulating lymphocytes due to altered lymphocyte trafficking, which prevented disease development in multiple models of autoimmune disease. Mechanistic studies of lymphoid tissue following oral administration of 2-acetyl-4(5)-(1(R),2(S),3(R),4-tetrahydroxybutyl)-imidazole (THI) 3 showed a clear relationship between reduced lyase activity, elevated S1P levels, and lower levels of circulating lymphocytes. Our internal medicinal chemistry efforts discovered potent analogues of 3 bearing heterocycles as chemical equivalents of the pendant carbonyl present in the parent structure. Reduction of S1PL activity by oral administration of these analogues recapitulated the phenotype of mice with genetically reduced S1PL expression.

Design, synthesis, and in vivo activity of novel inhibitors of delta-5 desaturase for the treatment of metabolic syndrome

The synthesis, SAR, and in vivo activity of inhibitors of delta-5 desaturase are described. Ring-constraint of the initial series provided access to a variety of in vitro active chemotypes, from which the indazole was selected. Examples from the indazole series displayed in vivo activity in reducing the enzymatic activity of liver delta-5 desaturase.