Redox modulation via a synthetic thiol compound reshapes energy metabolism in endothelial cells and ameliorates angiogenic expression in a co-culture study with activated macrophages

: The vascular endothelium is the first interface exposed to circulating compounds and oxidative as well as pro-inflammatory stimuli. Nowadays, cysteine pro-drugs are emerging as new and potential therapies in cardiovascular and inflammatory diseases due to their cytoprotective effects. In this study, the effects of redox modulation by a synthetic thiol compound, i.e., I-152, a precursor of N-acetylcysteine (NAC) and cysteamine (MEA), were evaluated after 6 h and 24 h treatment on human umbilical cord endothelial cell (HUVECs) energy metabolism. Following I-152 treatment, higher cysteine and glutathione (GSH) content were detected via HPLC, in concomitance with I-152 derivatives, i.e., NAC and MEA. Untargeted metabolomics confirmed GSH upregulation and NAC presence in addition to I-152 itself and other metabolites, such as dithiol compound (NACMEAA) and triacetylated I-152. Mass spectrometry revealed that I-152 boosted ATP production, specifically through the mitochondrial OXPHOS, as determined via Seahorse assay without inducing oxidative stress. Additionally, I-152 treatment of HUVECs before co-culture with LPS-stimulated macrophages provided GSH and cysteine sustainment and attenuated the transcription of adhesion molecules as well as iNOS expression. Identifying the impact of redox regulation in physiological conditions and the possible metabolic targets could aid the application of novel thiol-based therapeutics.