An Anoxia-starvation Model for Ischemia/Reperfusion in <em>C. elegans</em>

Protocols for anoxia/starvation in the genetic model organism C. elegans simulate ischemia/reperfusion. Worms are separated from bacterial food and placed ...

Universidade De São Paulo (USP)

Universidade de São Paulo

Mitochondrial calcium-activated K(+) (mitoK(Ca)) channels have been described as channels that are activated by Ca(2+), inner mitochondrial membrane depolarization and drugs such as NS-1619. NS-1619 is cardioprotective, leading to the assumption that this effect is related to the opening of mitoK(Ca) channels. Here, we show several weaknesses in this hypothesis.

Pharmacological and physiological stimuli do not promote Ca(2+)-sensitive K+ channel activity in isolated heart mitochondria.

Mitochondria are the central coordinators of energy metabolism and alterations in their function and number have long been associated with metabolic disorders such as obesity, diabetes and hyperlipidemias. Since oxidative phosphorylation requires an electrochemical gradient across the inner mitochondrial membrane, ion channels in this membrane certainly must play an important role in the regulation of energy metabolism. However, in many experimental settings, the relationship between the activity of mitochondrial ion transport and metabolic disorders is still poorly understood. This review briefly summarizes some aspects of mitochondrial H+ transport (promoted by uncoupling proteins, UCPs), Ca2+ and K+ uniporters which may be determinant in metabolic disorders.

Mitochondrial ion transport pathways: role in metabolic diseases.

The mitochondrial ATP-sensitive potassium channel (mK(ATP)) is important in the protective mechanism of ischemic preconditioning (IPC). The channel is reportedly sensitive to reactive oxygen and nitrogen species, and the aim of this study was to compare such species in parallel, to build a more comprehensive picture of mK(ATP) regulation. mK(ATP) activity was measured by both osmotic swelling and Tl(+) flux assays, in isolated rat heart mitochondria. An isolated adult rat cardiomyocyte model of ischemia-reperfusion (IR) injury was also used to determine the role of mK(ATP) in cardioprotection by nitroxyl. Key findings were as follows: (i) mK(ATP) was activated by O(2)(-) and H(2)O(2) but not other peroxides. (ii) mK(ATP) was inhibited by NADPH. (iii) mK(ATP) was activated by S-nitrosothiols, nitroxyl, and nitrolinoleate. The latter two species also inhibited mitochondrial complex II. (iv) Nitroxyl protected cardiomyocytes against IR injury in an mK(ATP)-dependent manner. Overall, these results suggest that the mK(ATP) channel is activated by specific reactive oxygen and nitrogen species, and inhibited by NADPH. The redox modulation of mK(ATP) may be an underlying mechanism for its regulation in the context of IPC. This article is part of a Special Issue entitled: Mitochondria and Cardioprotection.

Redox regulation of the mitochondrial K(ATP) channel in cardioprotection.

Conocimiento de ubicaci&oacute;n y subcompartmentalization intracelular es esencial para la comprensi&oacute;n de los procesos redox, porque deben generarse oxidantes, debido a su naturaleza reactiva, cerca de las mol&eacute;culas modificadas en se&ntilde;alizaci&oacute;n y da&ntilde;ar los procesos. Aqu&iacute; discutimos redox conocidas caracter&iacute;sticas de varios microambientes mitocondriales. Puntos cubiertos son los lugares de generaci&oacute;n mitocondrial oxidante, caracter&iacute;sticas de los sistemas antioxidantes en varios compartimientos mitocondriales y caracter&iacute;sticas de la difusi&oacute;n de oxidantes en las mitocondrias. Tambi&eacute;n repasamos las t&eacute;cnicas utilizadas para medir el estado redox en subcompartimientos mitocondriales, antioxidantes dirigidos a subcompartimientos mitocondriales y los problemas metodol&oacute;gicos que deben ser abordados al utilizar estas herramientas.

Compartimentaci&oacute;n mitocondrial de procesos redox.

&#x4F4D;&#x7F6E;&#x548C;&#x80DE;&#x5185; subcompartmentalization &#x7684;&#x77E5;&#x8BC6;&#x7406;&#x89E3;&#x7684;&#x6C27;&#x5316;&#x8FD8;&#x539F;&#x8FC7;&#x7A0B;&#x81F3;&#x5173;&#x91CD;&#x8981;&#xFF0C;&#x56E0;&#x4E3A;&#x6C27;&#x5316;&#x5242;&#xFF0C;&#x7531;&#x4E8E;&#x5176;&#x65E0;&#x529F;&#x6027;&#x8D28;&#xFF0C;&#x5FC5;&#x987B;&#x751F;&#x6210;&#x63A5;&#x8FD1;&#x7684;&#x5206;&#x5B50;&#x4FE1;&#x53F7;&#x8F6C;&#x5BFC;&#x548C;&#x7834;&#x574F;&#x8FC7;&#x7A0B;&#x4E2D;&#x4FEE;&#x6539;&#x3002;&#x5728;&#x8FD9;&#x91CC;&#x6211;&#x4EEC;&#x8BA8;&#x8BBA;&#x5DF2;&#x77E5;&#x6C27;&#x5316;&#x8FD8;&#x539F;&#x7279;&#x6027;&#x7684;&#x5404;&#x79CD;&#x7EBF;&#x7C92;&#x4F53;&#x7684;&#x5FAE;&#x89C2;&#x73AF;&#x5883;&#x3002;&#x6DB5;&#x76D6;&#x7684;&#x8981;&#x70B9;&#x662F;&#x7EBF;&#x7C92;&#x4F53;&#x6C27;&#x5316;&#x751F;&#x6210;&#x3001; &#x5404;&#x79CD;&#x7684;&#x7EBF;&#x7C92;&#x4F53;&#x8F66;&#x53A2;&#x5185;&#x6297;&#x6C27;&#x5316;&#x7CFB;&#x7EDF;&#x7684;&#x7279;&#x6027;&#x548C;&#x6269;&#x6563;&#x7279;&#x6027;&#x7684;&#x6C27;&#x5316;&#x5242;&#x5728;&#x7EBF;&#x7C92;&#x4F53;&#x4E2D;&#x7684;&#x4F4D;&#x7F6E;&#x3002;&#x6211;&#x4EEC;&#x4EA6;&#x68C0;&#x8BA8;&#x4E86;&#x7528;&#x6765;&#x8861;&#x91CF;&#x5728;&#x7EBF;&#x7C92;&#x4F53; subcompartments&#xFF0C;&#x6709;&#x9488;&#x5BF9;&#x6027;&#x7684;&#x5BF9;&#x7EBF;&#x7C92;&#x4F53; subcompartments&#xFF0C;&#x5E76;&#x4F7F;&#x7528;&#x8FD9;&#x4E9B;&#x5DE5;&#x5177;&#x65F6;&#x5FC5;&#x987B;&#x5904;&#x7406;&#x7684;&#x65B9;&#x6CD5;&#x5173;&#x6CE8;&#x6297;&#x6C27;&#x5316;&#x5242;&#x7684;&#x6C27;&#x5316;&#x8FD8;&#x539F;&#x72B6;&#x6001;&#x7684;&#x6280;&#x672F;&#x3002;

&#x7EBF;&#x7C92;&#x4F53;&#x7684;&#x6C27;&#x5316;&#x8FD8;&#x539F;&#x8FC7;&#x7A0B;&#x5404;&#x81EA;&#x4E3A;&#x653F;&#x7684;&#x73B0;&#x8C61;&#x3002;

Knowledge of location and intracellular subcompartmentalization is essential for the understanding of redox processes, because oxidants, owing to their reactive nature, must be generated close to the molecules modified in both signaling and damaging processes. Here we discuss known redox characteristics of various mitochondrial microenvironments. Points covered are the locations of mitochondrial oxidant generation, characteristics of antioxidant systems in various mitochondrial compartments, and diffusion characteristics of oxidants in mitochondria. We also review techniques used to measure redox state in mitochondrial subcompartments, antioxidants targeted to mitochondrial subcompartments, and methodological concerns that must be addressed when using these tools.

Mitochondrial compartmentalization of redox processes.

Connaissance de l&#39;emplacement et subcompartmentalization intracellulaire est essentiel pour la compr&eacute;hension des processus d&#39;oxydor&eacute;duction, car oxydants, en raison de leur nature r&eacute;active, doivent &ecirc;tre produites pr&egrave;s les mol&eacute;cules en signalisation et endommager le processus de modification. Ici nous discutons des caract&eacute;ristiques connues r&eacute;dox de divers micro-environnements mitochondriales. Points trait&eacute;s sont les emplacements de la g&eacute;n&eacute;ration de l&#39;oxydant mitochondrique, caract&eacute;ristiques des syst&egrave;mes antioxydants dans divers compartiments mitochondriales et caract&eacute;ristiques de propagation des oxydants dans les mitochondries. Nous examinons &eacute;galement les techniques utilis&eacute;es pour mesurer l&#39;&eacute;tat d&#39;oxydor&eacute;duction en sous-compartiments mitochondriales, antioxydants cibl&eacute;s sous-compartiments mitochondriales et les pr&eacute;occupations m&eacute;thodologiques qui doivent &ecirc;tre abord&eacute;es lors de l&#39;utilisation de ces outils.

Compartimentation mitochondriale des processus r&eacute;dox.

Kenntnis der Lage und intrazellul&auml;re Subcompartmentalization ist wesentlich f&uuml;r das Verst&auml;ndnis von Redox-Prozessen, weil Oxidantien, aufgrund ihrer reaktive Natur generiert werden m&uuml;ssen, in der N&auml;he der Molek&uuml;le signalisieren sowohl sch&auml;dliche Prozesse ge&auml;ndert. Hier diskutieren wir bekannte Redox-Merkmale der verschiedenen mitochondrialen Mikroumgebungen. Punkte abgedeckt sind die Standorte der Generierung mitochondrischen Oxidationsmittel, Merkmale der antioxidativen Systeme in verschiedenen mitochondrialen F&auml;cher und Verbreitung Merkmale von Oxidantien in den Mitochondrien. Wir &uuml;berpr&uuml;fen auch Techniken zur Messung der Redox-Zustand in mitochondrialen Subcompartments, Antioxidantien, die gezielt auf mitochondriale Subcompartments und methodischen Bedenken, die angegangen werden m&uuml;ssen, wenn Sie diese Tools verwenden.

Mitochondriale Untergliederung von Redox-Prozessen.

Conoscenza della posizione e subcompartmentalization intracellulare &egrave; essenziale per la comprensione dei processi redox, perch&eacute; ossidanti, a causa della loro natura reattiva, devono essere generati vicino le molecole modificate nella segnalazione sia danneggiando i processi. Qui discutiamo caratteristiche redox noto dei vari microambienti mitocondriale. Punti coperti sono le posizioni di generazione mitocondriale ossidante, caratteristiche dei sistemi antiossidanti in vari compartimenti mitocondriali e diffusione di ossidanti nei mitocondri. Rivediamo anche tecniche utilizzate per la misura dello stato redox in subcompartments mitocondriale, antiossidanti mirati a subcompartments mitocondriale e le preoccupazioni metodologiche che devono essere affrontate quando si utilizzano questi strumenti.

Compartimentazione mitocondriale dei processi redox.

&#x30AA;&#x30AD;&#x30B7;&#x30C0;&#x30F3;&#x30C8;&#x3001;&#x305D;&#x306E;&#x53CD;&#x5FDC;&#x6027;&#x306E;&#x6027;&#x8CEA;&#x306B;&#x3088;&#x308A;&#x30B7;&#x30B0;&#x30CA;&#x30EA;&#x30F3;&#x30B0;&#x3068;&#x640D;&#x50B7;&#x306E;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x306E;&#x4E21;&#x65B9;&#x3067;&#x5909;&#x66F4;&#x5206;&#x5B50;&#x306E;&#x8FD1;&#x304F;&#x306B;&#x751F;&#x6210;&#x3059;&#x308B;&#x5FC5;&#x8981;&#x304C;&#x3042;&#x308A;&#x307E;&#x3059;&#x306E;&#x3067;&#x5834;&#x6240;&#x3068;&#x7D30;&#x80DE;&#x5185; subcompartmentalization &#x306E;&#x77E5;&#x8B58;&#x306F;&#x9178;&#x5316;&#x9084;&#x5143;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x306E;&#x7406;&#x89E3;&#x306E;&#x305F;&#x3081;&#x306B;&#x4E0D;&#x53EF;&#x6B20;&#x3067;&#x3059;&#x3002;&#x3053;&#x3053;&#x3067;&#x69D8;&#x3005; &#x306A;&#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;&#x5FAE;&#x5C0F;&#x306E;&#x77E5;&#x3089;&#x308C;&#x3066;&#x3044;&#x308B;&#x9178;&#x5316;&#x9084;&#x5143;&#x7279;&#x6027;&#x3092;&#x8B70;&#x8AD6;&#x3057;&#x307E;&#x3059;&#x3002;&#x8986;&#x308F;&#x308C;&#x3066;&#x30DD;&#x30A4;&#x30F3;&#x30C8; &#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2; &#x30AA;&#x30AD;&#x30B7;&#x30C0;&#x30F3;&#x30C8;&#x751F;&#x6210;, &#x69D8;&#x3005; &#x306A;&#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;&#x306E;&#x30B3;&#x30F3;&#x30D1;&#x30FC;&#x30C8;&#x30E1;&#x30F3;&#x30C8;&#x306B;&#x304A;&#x3051;&#x308B;&#x6297;&#x9178;&#x5316;&#x7CFB;&#x306E;&#x7279;&#x6027;&#x3068;&#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;&#x306B;&#x304A;&#x3051;&#x308B;&#x30AA;&#x30AD;&#x30B7;&#x30C0;&#x30F3;&#x30C8;&#x6FC3;&#x5EA6;&#x306E;&#x62E1;&#x6563;&#x7279;&#x6027;&#x306E;&#x5834;&#x6240;&#x3067;&#x3059;&#x3002;&#x307E;&#x305F;&#x3001;&#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2; &#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;, &#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;&#x306E;&#x30DF;&#x30C8;&#x30B3;&#x30F3;&#x30C9;&#x30EA;&#x30A2;&#x304A;&#x3088;&#x3073;&#x3053;&#x308C;&#x3089;&#x306E;&#x30C4;&#x30FC;&#x30EB;&#x3092;&#x4F7F;&#x7528;&#x3059;&#x308B;&#x3068;&#x304D;&#x306B;&#x5BFE;&#x51E6;&#x3059;&#x308B;&#x5FC5;&#x8981;&#x304C;&#x3042;&#x308B;&#x65B9;&#x6CD5;&#x8AD6;&#x7684;&#x61F8;&#x5FF5;&#x5BFE;&#x8C61;&#x3068;&#x6297;&#x9178;&#x5316;&#x7269;&#x8CEA;&#x306E;&#x9178;&#x5316;&#x9084;&#x5143;&#x72B6;&#x614B;&#x3092;&#x6E2C;&#x5B9A;&#x3059;&#x308B;&#x305F;&#x3081;&#x306E;&#x30C6;&#x30AF;&#x30CB;&#x30C3;&#x30AF;&#x3092;&#x78BA;&#x8A8D;&#x3057;&#x307E;&#x3059;&#x3002;

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Oxidants &#xADF8;&#xB4E4;&#xC758; &#xBC18;&#xC751;&#xC131; &#xC131;&#xACA9; &#xB54C;&#xBB38;&#xC5D0; &#xC2E0;&#xD638; &#xBC0F; &#xD504;&#xB85C;&#xC138;&#xC2A4;&#xC758; &#xC190;&#xC0C1;&#xC744; &#xC218;&#xC815; &#xD558;&#xB294; &#xBD84;&#xC790;&#xC5D0; &#xAC00;&#xAE4C;&#xC6B4; &#xC0DD;&#xC131; &#xD574;&#xC57C; &#xD558;&#xAE30; &#xB54C;&#xBB38;&#xC5D0; &#xC704;&#xCE58; &#xBC0F; &#xC138;&#xD3EC;&#xB0B4; subcompartmentalization&#xC758; &#xAE30;&#xC220; redox &#xD504;&#xB85C;&#xC138;&#xC2A4;&#xC758; &#xC774;&#xD574;&#xB97C; &#xC704;&#xD574; &#xD544;&#xC218;&#xC801; &#xC774;&#xB2E4;. &#xC5EC;&#xAE30;&#xC5D0; &#xC6B0;&#xB9AC;&#xAC00; &#xC54C;&#xB824;&#xC9C4;&#xB41C; redox &#xD2B9;&#xC131; &#xB2E4;&#xC591; &#xD55C; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; microenvironments&#xC758; &#xB17C;&#xC758;. &#xC801;&#xC6A9; &#xD3EC;&#xC778;&#xD2B8;&#xB294; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; &#xC81C; &#xC0DD;&#xC131;, &#xB2E4;&#xC591; &#xD55C; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; &#xAD6C;&#xD68D;&#xC5D0;&#xC11C; &#xD56D; &#xC0B0;&#xD654; &#xC2DC;&#xC2A4;&#xD15C;&#xC758; &#xD2B9;&#xC131; &#xBC0F; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544;&#xC5D0; oxidants&#xC758; &#xD655;&#xC0B0; &#xD2B9;&#xC131; &#xC704;&#xCE58;&#xC785;&#xB2C8;&#xB2E4;. &#xB610;&#xD55C; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; subcompartments, &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; subcompartments &#xBC0F; &#xC774;&#xB7EC;&#xD55C; &#xB3C4;&#xAD6C;&#xB97C; &#xC0AC;&#xC6A9;&#xD560; &#xB54C; &#xD574;&#xACB0; &#xD574;&#xC57C; &#xD558;&#xB294; &#xBC29;&#xBC95;&#xB860; &#xBB38;&#xC81C;&#xB97C; &#xB300;&#xC0C1;&#xC73C;&#xB85C; &#xD558;&#xB294; &#xD56D; &#xC0B0;&#xD654; &#xBB3C;&#xC9C8;&#xC758;&#xC5D0;&#xC11C; &#xC0B0;&#xD654; &#xC0C1;&#xD0DC;&#xB97C; &#xCE21;&#xC815; &#xD558;&#xB294; &#xB370; &#xC0AC;&#xC6A9; &#xD558;&#xB294; &#xAE30;&#xC220;&#xC744; &#xAC80;&#xD1A0; &#xD558; &#xACE0;.

Redox &#xD504;&#xB85C;&#xC138;&#xC2A4;&#xC758; &#xBBF8;&#xD1A0; &#xCF58; &#xB4DC;&#xB9AC; &#xC544; &#xBCF4;&#xD5D8;&#xD68C;&#xC0AC;&#xC785;&#xB2C8;&#xB2E4;.

The carbon dioxide/bicarbonate (CO(2)/HCO(3)(-)) pair is the main biological pH buffer. However, its influence on biological processes, and in particular redox processes, is still poorly explored. Here we study the effect of CO(2)/HCO(3)(-) on ischemic injury in three distinct models (cardiac HL-1 cells, perfused rat heart, and Caenorhabditis elegans). We found that, although various concentrations of CO(2)/HCO(3)(-) do not affect function under basal conditions, ischemia-reperfusion or similar insults in the presence of higher CO(2)/HCO(3)(-) resulted in greater functional loss associated with higher oxidative damage in all models. Because the effect of CO(2)/HCO(3)(-) was observed in all models tested, we believe this buffer is an important determinant of oxidative damage after ischemia-reperfusion.

Bicarbonate modulates oxidative and functional damage in ischemia-reperfusion.

Exercise training is a well-known coadjuvant in heart failure treatment; however, the molecular mechanisms underlying its beneficial effects remain elusive. Despite the primary cause, heart failure is often preceded by two distinct phenomena: mitochondria dysfunction and cytosolic protein quality control disruption. The objective of the study was to determine the contribution of exercise training in regulating cardiac mitochondria metabolism and cytosolic protein quality control in a post-myocardial infarction-induced heart failure (MI-HF) animal model. Our data demonstrated that isolated cardiac mitochondria from MI-HF rats displayed decreased oxygen consumption, reduced maximum calcium uptake and elevated H₂O₂ release. These changes were accompanied by exacerbated cardiac oxidative stress and proteasomal insufficiency. Declined proteasomal activity contributes to cardiac protein quality control disruption in our MI-HF model. Using cultured neonatal cardiomyocytes, we showed that either antimycin A or H₂O₂ resulted in inactivation of proteasomal peptidase activity, accumulation of oxidized proteins and cell death, recapitulating our in vivo model. Of interest, eight weeks of exercise training improved cardiac function, peak oxygen uptake and exercise tolerance in MI-HF rats. Moreover, exercise training restored mitochondrial oxygen consumption, increased Ca²⁺-induced permeability transition and reduced H₂O₂ release in MI-HF rats. These changes were followed by reduced oxidative stress and better cardiac protein quality control. Taken together, our findings uncover the potential contribution of mitochondrial dysfunction and cytosolic protein quality control disruption to heart failure and highlight the positive effects of exercise training in re-establishing cardiac mitochondrial physiology and protein quality control, reinforcing the importance of this intervention as a non-pharmacological tool for heart failure therapy.

Bruno B. Queliconi

Departamento de Bioquímica,
Instituto de Química,
Departamento de Bioquímica, Instituto de Química

Universidade De São Paulo (USP)

An Anoxia-starvation Model for Ischemia/Reperfusion in C. elegans

Bruno B. Queliconi

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Departamento de Bioquímica,Instituto de Química,Departamento de Bioquímica, Instituto de Química

Universidade De São Paulo (USP)

An Anoxia-starvation Model for Ischemia/Reperfusion in C. elegans

Departamento de Bioquímica,
Instituto de Química,
Departamento de Bioquímica, Instituto de Química