Characterization of PKCα-rutin interactions and its application as a treatment strategy for PAH by inhibiting ferroptosis

As a common plant-derived dietary flavonoid, rutin receives the widespread attention because of its good antioxidant bioactivities. Protein kinase Cα (PKCα) is a serine/threonine kinase that is involved in uncountable cellular processes, among which ferroptosis, a novel form of cell death, is triggered by lipid peroxidation and has been reported to associate with pulmonary arterial hypertension (PAH). But it is still not well appreciated how rutin inhibits ferroptosis in PAH and what function of PKCα plays in this process. In this study, we firstly observed whether rutin could prevent PAH by attenuating ferroptosis with PAH animal model and pulmonary artery smooth muscle cells (PASMCs) under hypoxia. Mitochondrial metabolomics and network pharmacology were employed to clarify the metabolic alteration and screen target proteins, results showed PKCα was a vital node in rutin regulating mitochondrial metabolism related to ferroptosis in PAH. Based on molecular docking and multispectral analysis, we found rutin could directly interact with PKCα through hydrogen bonds, which could induce static quenching, and then influence the secondary structure of PKCα. In conclusion, these findings mainly point to a novel mechanism that rutin protect PAH rat by modifying the structure, altering activity of PKCα, and then suppressing ferroptosis. This work was great helpful to reveal that the interaction behaviours between small molecules and bio-macromolecules are the critical point to develop the natural biological active ingredients and give an insight into the potential applications of flavonoid in health and disease.