Drug repurposing for renin inhibition: identifying panobinostat for hypertension management

Renin, an aspartyl protease enzyme, is a crucial part of the renin-angiotensin-aldosterone system (RAAS) that regulates blood pressure. However, numerous renin inhibitors, including Aliskiren, Zankiren, Enalkiren, Fasidotril, and Remikiren, are in the clinical arena of managing hypertension, but they are associated with numerous drawbacks. The important one includes modest efficacy in contrast to other antihypertensive agents, which reduces their use as monotherapy; secondly, the related side effects, including hyperkalemia and renal impairment. Thus, considering the unmet need to identify new renin inhibitors, we applied the drug repurposing technique on an 1880 US FDA-approved small molecules database. The research was achieved by performing the structure-based virtual screening (SBVD) on FDA-approved drugs, which was well supported by molecular docking, dynamics, and mechanics studies. This work identified Panobinostat as a possible lead renin inhibitor. The in vitro Elisa-based assay revealed Panobinostat has the potential to inhibit the renin enzyme at the half-maximal concentration (IC₅₀) of 201.27 nM, while standard renin inhibitor Aliskiren portrayed an IC₅₀ of 162.22 nM. The comparable potency to clinical renin inhibitors presents this HDAC inhibitor as a dual-functioning ligand. The findings are significant and well correlated with the plethora of evidence suggesting the role of HDACs in regulating RAAS and cardiovascular functions via the post-translational level modulation of chromatins' structures and functions.