Proeryptotic Activity of 4-Hydroxynonenal: A New Potential Physiopathological Role for Lipid Peroxidation Products

• Main Authors: Mario Allegra, Ignazio Restivo, Alberto Fucarino, Alessandro Pitruzzella, Sonya Vasto, Maria Antonia Livrea, Luisa Tesoriere, Alessandro Attanzio
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Biomolecules
• Subjects: 4-hydroxynonenal; lipid peroxidation products; eryptosis; prostaglandins; RBC; inflammation
• Online Access: https://www.mdpi.com/2218-273X/10/5/770

Background: Eryptosis is a physiological, apoptosis-like death of injured erythrocytes crucial to prevent premature haemolysis and the pathological sequalae generated by cell-free haemoglobin. When dysregulated, the process is associated to several inflammatory-based pathologies. 4-Hydroxy-trans-2-nonenal (HNE) is an endogenous signalling molecule at physiological levels and, at higher concentrations, is involved in the pathogenesis of several inflammatory-based diseases. This work evaluated whether HNE could induce eryptosis in human erythrocytes. Methods: Measurements of phosphatidylserine, cell volume, intracellular oxidants, Ca⁺⁺, glutathione, ICAM-1, and ceramide were assessed by flow cytometry. Scanning electron microscopy evaluated morphological alterations of erythrocytes. Western blotting assessed caspases. PGE₂ was measured by ELISA. Adhesion of erythrocytes on endothelial cells was evaluated by gravity adherence assay. Results: HNE in the concentration range between 10–100 µM induces eryptosis, morphological alterations correlated to caspase-3 activation, and increased Ca⁺⁺ levels. The process is not mediated by redox-dependent mechanisms; rather, it strongly depends on PGE₂ and ceramide. Interestingly, HNE induces significant increase of erythrocytes adhesion to endothelial cells (ECs) that are in turn dysfunctionated as evident by overexpression of ICAM-1. Conclusions: Our results unveil a new physiopathological role for HNE, provide mechanistic details of the HNE-induced eryptosis, and suggest a novel mechanism through which HNE could exert pro-inflammatory effects.