A Novel N-Substituted Valine Derivative with Unique Peroxisome Proliferator-Activated Receptor gamma Binding Properties and Biological Activities

A proprietary library of novel N-aryl-substituted amino acid derivatives bearing a hydroxamate head group allowed the identification of compound 3a that possesses weak proadipogenic and peroxisome proliferator-activated receptor gamma (PPAR gamma) activating properties. The systematic optimization of 3a, in order to improve its PPAR gamma agonist activity, led to the synthesis of compound 7j (N-aryl-substituted valine derivative) that possesses dual PPAR gamma/PPAR alpha agonistic activity. Structural and kinetic analyses reveal that 7j occupies the typical ligand binding domain of the PPAR gamma agonists with, however, a unique high-affinity binding mode. Furthermore, 7j is highly effective in preventing cyclin-dependent kinase 5-mediated phosphorylation of PPAR gamma serine 273. Although less proadipogenic than rosiglitazone, 7j significantly increases adipocyte insulin-stimulated glucose uptake and efficiently promotes white-to-brown adipocyte conversion. In addition, 7j prevents oleic acid-induced lipid accumulation in hepatoma cells. The unique biochemical properties and biological activities of compound 7j suggest that it would be a promising candidate for the development of compounds to reduce insulin resistance, obesity, and nonalcoholic fatty liver disease.