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Mitochondrial complex I in the post-ischemic heart: reperfusion-mediated oxidative injury and protein cysteine sulfonation.

ABSTRACT: A serious consequence of ischemia-reperfusion injury (I/R) is oxidative damage leading to mitochondrial dysfunction. Such I/R-induced mitochondrial dysfunction is observed as impaired state 3 respiration and overproduction of O2-. The cascading ROS can propagate cysteine oxidation on mitochondrial complex I and add insult to injury. Herein we employed LC-MS/MS to identify protein sulfonation of complex I in mitochondria from the infarct region of rat hearts subjected to 30-min of coronary ligation and 24-h of reperfusion in vivo as well as the mitochondria of sham controls. Mitochondrial preparations from the I/R regions had enhanced sulfonation levels on the cysteine ligands of iron?sulfur clusters, including N3 (C425), N1b (C92), N4 (C226), N2 (C158/C188), and N1a (C134/C139). The 4Fe-4S centers of N3, N1b, N4, and N2 are key redox-active components of complex I, thus sulfonation of metal-binding sites impaired the main electron transfer pathway. The binuclear N1a has a very low redox potential and an antioxidative function. Increased C134/C139 sulfonation by I/R impaired the N1a cluster, potentially contributing to overall O2- generation by the FMN moiety of complex I. MS analysis also revealed I/R-mediated increased sulfonation at the core subunits of 51?kDa (C125, C187, C206, C238, C255, C286), 75?kDa (C367, C554, C564, C727), 49?kDa (C146, C326, C347), and PSST (C188). These results were consistent with the consensus indicating that 51?kDa and 75?kDa are two of major subunits hosting regulatory thiols, and their enhanced sulfonation by I/R predisposed the myocardium to further oxidant stress with impaired ubiquinone reduction. MS analysis further showed I/R-mediated enhanced sulfonation at the supernumerary subunits of 42?kDa (C67, C112, C183, C253), 15?kDa (C43), and 13?kDa (C79). The 42?kDa protein is metazoan-specific, which was reported to stabilize mammalian complex I. C43 of the 15?kDa subunit forms an intramolecular disulfide bond with C56, which was reported to stabilize complex I structure. C79 of the 13?kDa subunit is involved in Zn2+-binding, which was reported functionally important for complex I assembly. C79 sulfonation by I/R was found to impair Zn2+-binding. No significant enhancement of protein sulfonation was observed in mitochondrial complex I from the rat heart subjected to 30-min ischemia alone in vivo despite a decreased state 3 respiration, suggesting that the physiologic conditions of hyperoxygenation during reperfusion mediated an increase in complex I sulfonation and oxidative injury. In conclusion, sulfonation of specific cysteines of complex I mediates I/R-induced mitochondrial dysfunction via impaired ETC activity, increasing •O2- production, and mediating redox dysfunction of complex I.

SUBMITTER: Kang PT

PROVIDER: S-EPMC6103816 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Mitochondrial complex I in the post-ischemic heart: reperfusion-mediated oxidative injury and protein cysteine sulfonation.

Kang Patrick T PT Chen Chwen-Lih CL Lin Paul P Zhang Liwen L Zweier Jay L JL Chen Yeong-Renn YR

Journal of molecular and cellular cardiology 20180720

A serious consequence of ischemia-reperfusion injury (I/R) is oxidative damage leading to mitochondrial dysfunction. Such I/R-induced mitochondrial dysfunction is observed as impaired state 3 respiration and overproduction of O<sub>2</sub><sup>-</sup>. The cascading ROS can propagate cysteine oxidation on mitochondrial complex I and add insult to injury. Herein we employed LC-MS/MS to identify protein sulfonation of complex I in mitochondria from the infarct region of rat hearts subjected to 30- ...[more]

PMID: 30031815

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Project description:A serious consequence of myocardial ischemia-reperfusion injury (I/R) is oxidative damage, which causes mitochondrial dysfunction. The cascading ROS can propagate and potentially induce heme bleaching and protein cysteine sulfonation (PrSO3H) of the mitochondrial electron transport chain. Herein we studied the mechanism of I/R-mediated irreversible oxidative injury of complex III in mitochondria from rat hearts subjected to 30-min of ischemia and 24-h of reperfusion in vivo. In the I/R region, the catalytic activity of complex III was significantly impaired. Spectroscopic analysis indicated that I/R mediated the destruction of hemes b and c + c1 in the mitochondria, supporting I/R-mediated complex III impairment. However, no significant impairment of complex III activity and heme damage were observed in mitochondria from the risk region of rat hearts subjected only to 30-min ischemia, despite a decreased state 3 respiration. In the I/R mitochondria, carbamidomethylated C122/C125 of cytochrome c1 via alkylating complex III with a down regulation of HCCS was exclusively detected, supporting I/R-mediated thioether defect of heme c1. LC-MS/MS analysis showed that I/R mitochondria had intensely increased complex III PrSO3H levels at the C236 ligand of the [2Fe2S] cluster of the Rieske iron‑sulfur protein (uqcrfs1), thus impairing the electron transport activity. MS analysis also indicated increased PrSO3H of the hinge protein at C65 and of cytochrome c1 at C140 and C220, which are confined in the intermembrane space. MS analysis also showed that I/R extensively enhanced the PrSO3H of the core 1 (uqcrc1) and core 2 (uqcrc2) subunits in the matrix compartment, thus supporting the conclusion that complex III releases ROS to both sides of the inner membrane during reperfusion. Analysis of ischemic mitochondria indicated a modest reduction from the basal level of complex III PrSO3H detected in the mitochondria of sham control hearts, suggesting that the physiologic hyperoxygenation and ROS overproduction during reperfusion mediated the enhancement of complex III PrSO3H. In conclusion, reperfusion-mediated heme damage with increased PrSO3H controls oxidative injury to complex III and aggravates mitochondrial dysfunction in the post-ischemic heart.

Project description:DJ-1 is a ubiquitously expressed protein that protects cells from stress through its conversion into an active protease. Recent work found that the active form of DJ-1 was induced in the ischemic heart as an endogenous mechanism to attenuate glycative stress-the non-enzymatic glycosylation of proteins. However, specific proteins protected from glycative stress by DJ-1 are not known. Given that mitochondrial electron transport proteins have a propensity for being targets of glycative stress, we investigated if DJ-1 regulates the glycation of Complex I and Complex III after myocardial ischemia-reperfusion (I/R) injury. Initial studies found that DJ-1 localized to the mitochondria and increased its interaction with Complex I and Complex III 3 days after the onset of myocardial I/R injury. Next, we investigated the role DJ-1 plays in modulating glycative stress in the mitochondria. Analysis revealed that compared to wild-type control mice, mitochondria from DJ-1 deficient (DJ-1 KO) hearts showed increased levels of glycative stress following I/R. Additionally, Complex I and Complex III glycation were found to be at higher levels in DJ-1 KO hearts. This corresponded with reduced complex activities, as well as reduced mitochondrial oxygen consumption ant ATP synthesis in the presence of pyruvate and malate. To further determine if DJ-1 influenced the glycation of the complexes, an adenoviral approach was used to over-express the active form of DJ-1(AAV9-DJ1ΔC). Under I/R conditions, the glycation of Complex I and Complex III were attenuated in hearts treated with AAV9-DJ1ΔC. This was accompanied by improvements in complex activities, oxygen consumption, and ATP production. Together, this data suggests that cardiac DJ-1 maintains Complex I and Complex III efficiency and mitochondrial function during the recovery from I/R injury. In elucidating a specific mechanism for DJ-1's role in the post-ischemic heart, these data break new ground for potential therapeutic strategies using DJ-1 as a target.

Project description:Acute kidney injury (AKI) is associated with an abrupt loss of kidney function that results in significant morbidity and mortality. Considerable effort has focused around the identification of diagnostic biomarkers and the analysis of molecular events. Most studies have adopted organ-wide approaches that do not fully capture the interplay among different cell types in the pathophysiology of AKI. To extend our understanding of molecular and cellular events in AKI, we developed a mouse line that enables the identification of translational profiles in specific cell types by CRE recombinase-dependent activation of an eGFP-tagged L10a ribosomal protein subunit, and consequently, translating ribosome affinity purification (TRAP) of mRNA populations. By utilizing cell-type specific CRE-driver lines, in this study we identify distinct cellular responses in an ischemia reperfusion injury (IRI) model of AKI. Cell-specific translational expression profiles were uncovered 24 hours after IRI from four populations enriched for distinct anatomical and cellular subgroups: nephron, interstitial cell populations, vascular endothelium, and macrophages/monocytes by Affymetrix microarray. A construct containing the CAGGS promoter driving eGFP-L10a, with a loxP-site flanked triple SV40 polyA cassette between promoter and eGFP-L10a cassette was targeted into the ubiquitously active Rosa26 locus. The upstream polyA cassette is designed to block activity of the downstream eGFP-L10a cassette. CRE-dependent removal of this transcriptional block activates eGFP::L10a production within the CRE-producing cell, and all of its descendants. Mice carrying the conditional eGFP-L10a allele, referred to as L10a, were maintained in a homozygous state. L10a mice were crossed to four CRE strains to activate eGFP::L10a expression in four predominantly non-overlapping cellular compartments in the kidney. A Six2-Tet-GFP::CRE allele is active exclusively within nephron progenitors; consequently, historical labeling results in eGFP::L10a expression throughout the main body of the nephron. A Foxd1-GFP::CRE allele is active in the progenitors of many of the interstitial cell lineages including those generating mesangial and non-glomerular pericytes. In addition, Foxd1 is normally expressed in podocytes. Cdh5-CRE is reported to be active throughout the vascular endothelium, and finally, Lyz2-CRE specifically labels cells of the myeloid lineage, notably macrophages, monocytes and dendritic cells. Mice carrying any CRE allele and the L10a allele are designated generically CRE-L10a. six2-L10a, foxd1-L10a, cdh5-L10a and lyz2-L10a denote specifically mice that are compound heterozygotes for the indicated CRE driver and L10a. CRE-L10a, L10a heterozygous littermates without CRE allele, C57BL/6 wild type mice were subjected to renal bilateral warm ischemia 28 minutes followed by 24-hour reperfusion when the kidney TRAP RNA and total RNA were isolated and subjected to Affymetrix microarray. Biological triplicates for each CRE-L10a line underwent no Surgery; sham Surgery and IRI treatment.

Project description:This study demonstrates that in mice subjected to hypoxia-ischemia (HI) brain injury isoflurane anesthesia initiated upon reperfusion limits a release of mitochondrial oxidative radicals by inhibiting a recovery of complex-I dependent mitochondrial respiration. This significantly attenuates an oxidative stress and reduces the extent of HI brain injury. Neonatal mice were subjected to HI, and at the initiation of reperfusion were exposed to isoflurane with or without mechanical ventilation. At the end of HI and isoflurane exposure cerebral mitochondrial respiration, H2O2 emission rates were measured followed by an assessment of cerebral oxidative damage and infarct volumes. At 8 weeks after HI navigational memory and brain atrophy were assessed. In vitro, direct effect of isoflurane on mitochondrial H2O2 emission was compared to that of complex-I inhibitor, rotenone. Compared to controls, 15 minutes of isoflurane anesthesia inhibited recovery of the compex I-dependent mitochondrial respiration and decreased H2O2 production in mitochondria supported with succinate. This was associated with reduced oxidative brain injury, superior navigational memory and decreased cerebral atrophy compared to the vehicle-treated HI-mice. Extended isoflurane anesthesia was associated with sluggish recovery of cerebral blood flow (CBF) and the neuroprotection was lost. However, when isoflurane anesthesia was supported with mechanical ventilation the CBF recovery improved, the event associated with further reduction of infarct volume compared to HI-mice exposed to isoflurane without respiratory support. Thus, in neonatal mice brief isoflurane anesthesia initiated at the onset of reperfusion limits mitochondrial release of oxidative radicals and attenuates an oxidative stress. This novel mechanism contributes to neuroprotective action of isoflurane. The use of mechanical ventilation during isoflurane anesthesia counterbalances negative effect of isoflurane anesthesia on recovery of cerebral circulation which potentiates protection against reperfusion injury.

Dataset Information

Mitochondrial complex I in the post-ischemic heart: reperfusion-mediated oxidative injury and protein cysteine sulfonation.

Publications

Mitochondrial complex I in the post-ischemic heart: reperfusion-mediated oxidative injury and protein cysteine sulfonation.

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