Structural basis for the hepatoprotective effects of antihypertensive 1,4-dihydropyridine drugs.

BACKGROUND: The 1,4-dihydropyridines (DHPs) are one of the most frequently prescribed classes of antihypertensive monotherapeutic agents worldwide. In addition to treating hypertension, DHPs also exert other beneficial effects, including hepatoprotective effects. However, the mechanism underlying the hepatoprotection remains unclear. METHODS: Biochemical AlphaScreen and cell-based reporter assays were employed to detect the activities of DHPs towards FXR. A crystallographic analysis was adopted to study the binding modes of four DHPs in complex with FXR. Acetaminophen (APAP)-treated wild-type and FXR knockout mice were used to investigate the functional dependence of the effects of the selected DHPs on FXR. RESULTS: A series of DHPs were uncovered as FXR ligands with different activities for FXR, suggesting FXR might serve as an alternative drug target for DHPs. The structural analysis illustrated the specific three-blade propeller binding modes of four DHPs to FXR and explained the detailed mechanisms by which DHPs bind to and are recognized by FXR. The results in mice demonstrated that cilnidipine protected the liver from APAP-induced injury in an FXR-dependent manner. CONCLUSIONS: This study reports the crystal structures of FXR in complex with four DHPs, and confirms that DHPs exert hepatoprotection by targeting FXR. GENERAL SIGNIFICANCE: Our research not only reveals valuable insight for the design and development of next-generation Ca2+ blocker drugs to provide safer and more effective treatments for cardiovascular disorders but also provides a novel and safe structural template for the development of drugs targeting FXR. Moreover, DHPs might be potentially repurposed to treat FXR-mediated diseases other than hypertension.