Ricerc@Sapienza

Biochemical mechanisms of hyperglycaemic injury are potential targets for novel therapeutic intervention aimed at reducing glucose toxicity, which is decreased but not completely prevented by current glucose-lowering treatment strategies. The glycolytic side product methylglyoxal (MGO) is a major mediator of glucose toxicity. Trapping MGO with ¿-carnosine (CAR), a selective scavenger of carbonyl species, was shown effective in protecting against diabetic vascular complications, an effect that was associated with suppressed Hypoxia-inducible factor 1-alpha (HIF-1¿) upregulation in the vasculature of diabetic mice. As part of a project financed by funds from the Sapienza University of Rome ( Bando Ricerca 2017), we investigated the role of MGO in driving high glucose (HG)-mediated HIF-1alfa induction and the associated Warburg effect and found that 1) CAR is able to reverse HIF-1¿ induction and related metabolic changes induced by HG; 2) MGO mimics the effect of HG on cellular bioenergetics. From a mechanistic view, we observed that glucose-derived MGO activates HIF-1¿ and leads to accumulation of toxic glucose metabolites (i.e., sorbitol and advanced glycation end-products). The aim of this project is twofold: 1) to assess the role of HIF-1¿, pyruvate kinase M2 (PKM2) and their interplay in renal cell dysfunction induced by HG; 2) to investigate the reciprocal modulating effects of HIF-1alfa and PKM2 expression and activity in HG conditions, resulting in a Warburg-like effect and glucose toxicity. PKM2 is a glycolytic enzyme that catalyzes the last step within glycolysis and has been recently involved in the pathogenesis of diabetic nephropathy in both humans and preclinical models. Though PKM2 is a well-known transcriptional target of HIF-1¿ and its pharmacological activation has been shown to reverse HG-induced mitochondrial dysfunction, the relationship between HIF-1¿ and PKM2 activity in cellular bioenergetics changes induced by HG has not yet been investigated