Novel fatty acid binding protein 4 (FABP4) inhibitors: Virtual screening, synthesis and crystal structure determination

• Compound m1 was discovered as an inhibitor of FABP4 by virtual screening.
• Derivatives of m1 were prepared for structure–activity relationship (SAR) studies.
• Compounds 9 and 10 exhibited remarkable inhibitory activities against FABP4.
• The binding mode of FABP4-9 and FABP4-10 were determined by X-ray diffraction analysis.

Fatty acid binding protein 4 (FABP4) is a potential drug target for diabetes and atherosclerosis. For discovering new chemical entities as FABP4 inhibitors, structure-based virtual screening (VS) was performed, bioassay demonstrated that 16 of 251 tested compounds are FABP4 inhibitors, among which compound m1 are more active than endogenous ligand linoleic acid (LA). Based on the structure of m1, new derivatives were designed and prepared, leading to the discovery of two more potent inhibitors, compounds 9 and 10. To further explore the binding mechanisms of these new inhibitors, we determined the X-ray structures of the complexes of FABP4-9 and FABP4-10, which revealed similar binding conformations of the two compounds. Residue Ser53 and Arg126 formed direct hydrogen bonding with the ligands. We also found that 10 could significantly reduce the levels of lipolysis on mouse 3T3-L1 adipocytes. Taken together, in silico, in vitro and crystallographic data provide useful hints for future development of novel inhibitors against FABP4.

Compound 10 was discovered as an inhibitor of FABP4, with an IC50 value of 4.0 μM. It could effectively inhibit forskolin-stimulated lipolysis on mouse 3T3-L1 adipocytes.Figure optionsDownload as PowerPoint slide