4-Hydroxynonenal Inhibits SIRT3 via Thiol-Specific Modification

Abstract

4-Hydroxynonenal (4-HNE) is an endogenous product of lipid peroxidation known to play a role in cellular signaling through protein modification and is a major precursor for protein carbonyl adducts found in alcoholic liver disease (ALD). In the present study, a greater than 2-fold increase in protein carbonylation of sirtuin 3 (SIRT3), a mitochondrial class III histone deacetylase, is reported in liver mitochondrial extracts of ethanol consuming mice. The consequence of this in vivo carbonylation on SIRT3 deacetylase activity is unknown. Interestingly, mitochondrial protein hyperacetylation was observed in a time-dependent increase in a model of chronic ethanol consumption; however, the underlying mechanisms for this remain unknown. Tandem mass spectrometry was used to identify and characterize the in vitro covalent modification of rSIRT3 by 4-HNE at Cys280, a critical zinc-binding residue, and the resulting inhibition of rSIRT3 activity via pathophysiologically relevant concentrations of 4-HNE. Computational-based molecular modeling simulations indicate that 4-HNE modification alters the conformation of the zinc-binding domain inducing minor changes within the active site, resulting in the allosteric inhibition of SIRT3 activity. These conformational data are supported by the calculated binding energies derived from molecular docking studies suggesting the substrate peptide of acetyl-CoA synthetase 2 (AceCS2-Kac), displays a greater affinity for native SIRT3 compared with the 4-HNE adducted protein. The results of this study characterize altered mitochondrial protein acetylation in a mouse model of chronic ethanol ingestion and thiol-specific allosteric inhibition of rSIRT3 resulting from 4-HNE adduction.

Alterations in fatty acid metabolism and sirtuin signaling characterize early type-2 diabetic hearts of fructose-fed rats

“…We speculate that the increased protein levels may represent an adaptive response to either a decrease in free NAD + , despite increased activity of complex I and related regeneration of NAD + (the total levels of which are increased in cardiac mitochondria from fructose‐fed rats), or SIRT3 carbonylation, which has been shown to negatively affect its activity (Fritz et al. 2011). Indeed, sirtuins are important in facilitating metabolic adaptations to nutritional stress (caloric restriction and overnutrition).…”

4-Hydroxynonenal Promotes Growth and Angiogenesis of Breast Cancer Cells through HIF-1α Stabilization

“…Furthermore, 4-HNE causes induction, phosphorylation, and nuclear accumulation of p53 (Patrick et al, 2005). SIRT3 and SIRT1 were reported to be covalently modified by 4-HNE (Fritz et al, 2011). This modification by 4-HNE can inhibit the catalytic activity of SIRT3 and SIRT1.…”

“…The activity of SIRT3 can be inhibited by 4-HNE (Fritz et al, 2011), we then investigated whether 4-HNE affects the levels of HIF-1α through SIRT3. Knockdown of SIRT3 increased the levels of HIF-1α and VEGF in MDA-MB-231 cells.…”

“…This modification by 4-HNE can inhibit SIRT3 deacetylase activity (Fritz et al, 2011). Moreover, SIRT3 was reported to destabilize HIF-1α protein and inhibit its activity (Finley et al, 2011).…”

“…Sirtuin-3 and Sirtuin-1 (SIRT3 and SIRT1) were reported to be covalently modified by 4-HNE (Caito et al, 2010;Fritz et al, 2011). This modification by 4-HNE can inhibit SIRT3 deacetylase activity (Fritz et al, 2011).…”