Pharmacological Down Regulation of PRMT1 Exhibits Antagonistic Effect on Cellular Senescence Mediated by DAHP: Computational Modelling and Experimental Validation

Abstract

Metformin is intended to function as an agonist of SIRT1, a nicotinamide adenine dinucleotide (NAD +)-dependent deacetylase that mediates a number of beneficial metabolic responses. We investigated the effect of metformin in DAHP (GTPCH1 inhibitor) treated EAhy926 endothelial cells on cellular senescence. Cellular senescence was evaluated through senescence associated parameters viz., namely Beta galactosidase assay, p21 and p53 mRNA expression, nicotinamide (NAD+ content), asymmetric dimethylarginine content (ADMA) content, protein arginine methylation (PRMT1) and Sirt 1 protein expression. We also performed an in silico investigation of the possible interactions between metformin and SIRT1 that focuses on molecular docking which revealed that metformin binds with Sirt1 and that the binding affinity of metformin with Sirt1 is prominent through docking score. Oxidative stress (OS) indices such as intracellular biopterin concentrations (tetrahydrobiopterin-BH4 and dihydrobiopterin-BH2) were also determined. Metformin treatment exhibited distinct anti senescence effect in endothelial cells by downregulating the senescence markers such as beta galactosidase activity, p21 and p53 gene expression and PRMT1 protein expression while upregulating NAD+ content and Sirt1 content compared to the respective controls. We postulate that metformin restores early onset of cellular senescence potentially through oxidative stress mediated cellular events in endothelial cells, one of a kind report.