α-ketoglutarate augments prolyl hydroxylase-2 mediated inactivation of phosphorylated-Akt to inhibit induced-thrombosis and inflammation

Abstract

Phosphorylation of Akt (pAkt) regulates multiple physiological and pathological processes including thrombosis and inflammation. In an approach to inhibit the pathological signalling of pAkt by prolyl-hydroxylase-2 (PHD2) we employed alpha-ketoglutarate (AKG), a cofactor of PHD2. Octyl-AKG supplementation to platelets promoted PHD2 activity through elevated intracellular AKG:succinate ratio and reduced aggregation in vitro by suppressing pAkt1(Thr308). Augmented PHD2 activity was confirmed by increased hydroxylated-proline alongside enhanced binding of PHD2 to pAkt in AKG-treated platelets. Contrastingly, inhibitors of PHD2 significantly increased pAkt1 in platelets. Octyl-AKG followed similar mechanism in monocytes to inhibit cytokine secretion in vitro. Our data also describe a suppressed pAkt1 and reduced activation of platelet and leukocyte obtained from mice supplemented with dietary-AKG, unaccompanied by alteration in their counts. Dietary-AKG significantly reduced clot formation and leukocyte accumulation in various organs including lung of mice treated with thrombosis-inducing agent carrageenan. Importantly, we observed a significant rescue effect of dietary-AKG on inflamed lung of SARS-CoV-2 infected hamsters. AKG significantly reduced leukocyte accumulation, clot formation and viral load alongside downmodulation of pAkt in lung of the infected animals. Therefore, our study suggests a safe implementation of dietary-AKG in prevention of Akt-driven anomalies including thrombosis and inflammation, highlighting a better pulmonary management in COVID-19.