Abstract
BackgroundHydrogen peroxide (H2O2)-induced mitochondrial oxidative damage is critical to intestinal ischemia/reperfusion (I/R) injury, and PRDX3 is an efficient H2O2 scavenger that protects cells from mitochondrial oxidative damage and apoptosis. However, the function of PRDX3 in intestinal I/R injury is unclear. The aim of this study was to investigate the precise mechanism underlying the involvement of PRDX3 in intestinal I/R injury. MethodsAn intestinal I/R model was established in mice with superior mesenteric artery occlusion, and Caco-2 cells were subjected to hypoxia/reoxygenation (H/R) for the in vivo simulation of I/R. ResultsPRDX3 expression was decreased during intestinal I/R injury, and PRDX3 overexpression significantly attenuated H/R-induced mitochondrial oxidative damage and apoptosis in Caco-2 cells. The level of acetylated PRDX3 was clearly increased both in vivo and in vitro. The inhibition of SIRTs by nicotinamide (NAM) increased the level of acetylated PRDX3 and impaired the antioxidative activity of PRDX3. Furthermore, NAM did not increase the acetylation of PRDX3 in sirtuin-3 (SIRT3)-knockdown Caco-2 cells. Importantly, PRDX3 acetylation was increased in mice lacking SIRT3, and this effect was accompanied by serious mitochondrial oxidative damage, apoptosis and remote organ damage after intestinal I/R injury. We screened potential sites of PRDX3 acetylation in the previously reported acetylproteome through immunoprecipitation (IP) experiments and found that SIRT3 deacetylates K253 on PRDX3 in Caco-2 cells. Furthermore, PRDX3 with the lysine residue K253 mutated to arginine (K253R) increased its dimerization in Caco-2 cells after subjected to 12 h hypoxia and followed 4 h reoxygenation. Caco-2 cells transfected with the K253R plasmid exhibited notably less mitochondrial damage and apoptosis, and transfection of the K253Q plasmid abolished the protective effect of PRDX3 overexpression. Analysis of ischemic intestines from clinical patients further verified the correlation between SIRT3 and PRDX3. ConclusionsPRDX3 is a key protective factor for intestinal I/R injury, and SIRT3-mediated PRDX3 deacetylation can alleviate intestinal I/R-induced mitochondrial oxidative damage and apoptosis.
Highlights
Intestinal ischemia/reperfusion (I/R) is a life-threatening condition involving mucosal barrier damage and bacterial translocation that initially occurs in the intestine and is a trigger for systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) [1,2,3]
The results showed that PRDX3 monomer was clearly decreased after 45 min of ischemia followed by 1–4 h of reperfusion, at 4 h, and gradually increased during the remaining 8 h of reperfusion (Fig. 1A)
Mitochondrial oxidative stress and cell apoptosis are the key pathogenic events resulting from intestinal I/R injury [5,50,51,52]
Summary
Intestinal ischemia/reperfusion (I/R) is a life-threatening condition involving mucosal barrier damage and bacterial translocation that initially occurs in the intestine and is a trigger for systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) [1,2,3]. Hydrogen peroxide (H2O2)-induced mitochondrial oxidative damage is critical to intestinal ischemia/reperfusion (I/R) injury, and PRDX3 is an efficient H2O2 scavenger that protects cells from mitochondrial oxidative damage and apoptosis. Results: PRDX3 expression was decreased during intestinal I/R injury, and PRDX3 overexpression significantly attenuated H/R-induced mitochondrial oxidative damage and apoptosis in Caco-2 cells. NAM did not increase the acetylation of PRDX3 in sirtuin-3 (SIRT3)-knockdown Caco-2 cells. PRDX3 acetylation was increased in mice lacking SIRT3, and this effect was accompanied by serious mitochondrial oxidative damage, apoptosis and remote organ damage after intestinal I/R injury. Caco-2 cells transfected with the K253R plasmid exhibited notably less mitochondrial damage and apoptosis, and transfection of the K253Q plasmid abolished the protective effect of PRDX3 overexpression. Conclusions: PRDX3 is a key protective factor for intestinal I/R injury, and SIRT3-mediated PRDX3 deacetylation can alleviate intestinal I/R-induced mitochondrial oxidative damage and apoptosis
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