An excessive increase in reactive oxygen species (ROS) levels is one of the main causes of mitochondrial dysfunction. However, when ROS levels are maintained in balance with antioxidant mechanisms, ROS fulfill the role of signaling molecules and modulate various physiological processes. Recent advances in mitochondrial bioenergetics research have revealed a significant interplay between mitochondrial peroxiredoxins (PRDXs) and monoamine oxidase-A (MAO-A) in regulating ROS levels. Both proteins are associated with hydrogen peroxide (H2O2), MAO-A as a producer and PRDXs as the primary antioxidant scavengers of H2O2. This review focuses on the currently available knowledge on the function of these proteins and their interaction, highlighting their importance in regulating oxidative damage, apoptosis, and metabolic adaptation in the heart. PRDXs not only scavenge excess H2O2, but also act as regulatory proteins, play an active role in redox signaling, and maintain mitochondrial membrane integrity. Overexpression of MAO-A is associated with increased oxidative damage, leading to mitochondrial dysfunction and subsequent progression of cardiovascular diseases (CVD), including ischemia/reperfusion injury and heart failure. Considering the central role of oxidative damage in the pathogenesis of many CVD, targeting PRDXs activation and MAO-A inhibition may offer new therapeutic strategies aimed at improving cardiac function under conditions of pathological load related to oxidative damage. Keywords: Mitochondria, Peroxiredoxin, Monoamine oxidase-A, Reactive oxygen species, Cardioprotective signaling.

• MeSH
• kardiovaskulární nemoci * metabolismus   MeSH
• lidé MeSH
• monoaminoxidasa * metabolismus   MeSH
• oxidační stres fyziologie   MeSH
• peroxiredoxiny * metabolismus   MeSH
• reaktivní formy kyslíku * metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• srdeční mitochondrie * metabolismus   enzymologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• monoaminoxidasa * MeSH
• peroxiredoxiny * MeSH
• reaktivní formy kyslíku * MeSH

Moderate cold acclimation (MCA) is a non-invasive intervention mitigating effects of various pathological conditions including myocardial infarction. We aim to determine the shortest cardioprotective regimen of MCA and the response of β1/2/3-adrenoceptors (β-AR), its downstream signaling, and inflammatory status, which play a role in cell-survival during myocardial infarction. Adult male Wistar rats were acclimated (9 °C, 1-3-10 days). Infarct size, echocardiography, western blotting, ELISA, mitochondrial respirometry, receptor binding assay, and quantitative immunofluorescence microscopy were carried out on left ventricular myocardium and brown adipose tissue (BAT). MultiPlex analysis of cytokines and chemokines in serum was accomplished. We found that short-term MCA reduced myocardial infarction, improved resistance of mitochondria to Ca2+-overload, and downregulated β1-ARs. The β2-ARs/protein kinase B/Akt were attenuated while β3-ARs translocated on the T-tubular system suggesting its activation. Protein kinase G (PKG) translocated to sarcoplasmic reticulum and phosphorylation of AMPKThr172 increased after 10 days. Principal component analysis revealed a significant shift in cytokine/chemokine serum levels on day 10 of acclimation, which corresponds to maturation of BAT. In conclusion, short-term MCA increases heart resilience to ischemia without any negative side effects such as hypertension or hypertrophy. Cold-elicited cardioprotection is accompanied by β1/2-AR desensitization, activation of the β3-AR/PKG/AMPK pathways, and an immunomodulatory effect.

• MeSH
• adrenergní látky * metabolismus   MeSH
• infarkt myokardu * patologie   MeSH
• krysa rodu Rattus MeSH
• myokard metabolismus   MeSH
• potkani Wistar MeSH
• proteinkinasy aktivované AMP metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adrenergní látky * MeSH
• proteinkinasy aktivované AMP MeSH

The β-adrenergic signaling pathways and antioxidant defence mechanisms play important roles in maintaining proper heart function. Here, we examined the effect of chronic normobaric hypoxia (CNH, 10% O2, 3 weeks) on myocardial β-adrenergic signaling and selected components of the antioxidant system in spontaneously hypertensive rats (SHR) and in a conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR with that of the more ischemia-resistant Brown Norway strain. Our investigations revealed some intriguing differences between the two strains at the level of β-adrenergic receptors (β-ARs), activity of adenylyl cyclase (AC) and monoamine oxidase A (MAO-A), as well as distinct changes after CNH exposure. The β2-AR/β1-AR ratio was significantly higher in SHR-mtBN than in SHR, apparently due to increased expression of β2-ARs. Adaptation to hypoxia elevated β2-ARs in SHR and decreased the total number of β-ARs in SHR-mtBN. In parallel, the ability of isoprenaline to stimulate AC activity was found to be higher in SHR-mtBN than that in SHR. Interestingly, the activity of MAO-A was notably lower in SHR-mtBN than in SHR, and it was markedly elevated in both strains after exposure to hypoxia. In addition to that, CNH markedly enhanced the expression of catalase and aldehyde dehydrogenase-2 in both strains, and decreased the expression of Cu/Zn superoxide dismutase in SHR. Adaptation to CNH intensified oxidative stress to a similar extent in both strains and elevated the IL-10/TNF-α ratio in SHR-mtBN only. These data indicate that alterations in the mitochondrial genome can result in peculiar changes in myocardial β-adrenergic signaling, MAO-A activity and antioxidant defence and may, thus, affect the adaptive responses to hypoxia.

• Klíčová slova
• Adenylyl cyclase, Antioxidant defence, Chronic hypoxia, Mitochondrial genome, Monoamine oxidase A, Myocardium, SHR, β-adrenergic receptors,
• MeSH
• adenylátcyklasy metabolismus   MeSH
• beta-adrenergní receptory metabolismus   MeSH
• hypoxie metabolismus   MeSH
• krysa rodu Rattus MeSH
• malondialdehyd metabolismus   MeSH
• monoaminoxidasa metabolismus   MeSH
• myokard metabolismus   MeSH
• potkani inbrední SHR MeSH
• signální transdukce fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adenylátcyklasy MeSH
• beta-adrenergní receptory MeSH
• malondialdehyd MeSH
• monoaminoxidasa MeSH

Adaptation to continuous normobaric hypoxia (CNH) protects the heart against acute ischemia/reperfusion injury. Recently, we have demonstrated the infarct size-limiting effect of CNH also in hearts of spontaneously hypertensive rats (SHR) and in conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR with that of more ischemia-resistant Brown Norway rats. Importantly, cardioprotective effect of CNH was more pronounced in SHR-mtBN than in SHR. Thus, here we aimed to identify candidate genes which may contribute to this difference between the strains. Rats were adapted to CNH (FiO2 0.1) for 3 weeks or kept at room air as normoxic controls. Screening of 45 transcripts was performed in left ventricles using Biomark Chip. Significant differences between the groups were analyzed by univariate analysis (ANOVA) and the genes contributing to the differences between the strains unmasked by CNH were identified by multivariate analyses (PCA, SOM). ANOVA with Bonferroni correction revealed that transcripts differently affected by CNH in SHR and SHR-mtBN belong predominantly to lipid metabolism and antioxidant defense. PCA divided four experimental groups into two main clusters corresponding to chronically hypoxic and normoxic groups, and differences between the strains were more pronounced after CNH. Subsequently, the following 14 candidate transcripts were selected by PCA, and confirmed by SOM analyses, that can contribute to the strain differences in cardioprotective phenotype afforded by CNH: Alkaline ceramidase 2 (Acer2), Fatty acid translocase (Cd36), Aconitase 1 (Aco1), Peroxisome proliferator activated receptor gamma (Pparg), Hemoxygenase 2 (Hmox2), Phospholipase A2 group IIA (Ppla2g2a), Dynamin-related protein (Drp), Protein kinase C epsilon (Pkce), Hexokinase 2 (Hk2), Sphingomyelin synthase 2 (Sgms2), Caspase 3 (Casp3), Mitofussin 1 (Mfn1), Phospholipase A2 group V (Pla2g5), and Catalase (Cat). Our data suggest that the stronger cardioprotective phenotype of conplastic SHR-mtBN strain afforded by CNH is associated with either preventing the drop or increasing the expression of transcripts related to energy metabolism, antioxidant response and mitochondrial dynamics.

• Klíčová slova
• SHR, SHR-mtBN, conplastic strain, hypoxia, left ventricle, metabolism,
• Publikační typ
• časopisecké články MeSH

Adaptation to chronic hypoxia represents a potential cardioprotective intervention reducing the extent of acute ischemia/reperfusion (I/R) injury, which is a major cause of death worldwide. The main objective of this study was to investigate the anti-apoptotic Akt/hexokinase 2 (HK2) pathway in hypoxic hearts subjected to I/R insult. Hearts isolated from male Wistar rats exposed either to continuous normobaric hypoxia (CNH; 10% O2) or to room air for 3 weeks were perfused according to Langendorff and subjected to 10 min of no-flow ischemia and 10 min of reperfusion. The hearts were collected either after ischemia or after reperfusion and used for protein analyses and quantitative fluorescence microscopy. The CNH resulted in increased levels of HK1 and HK2 proteins and the total HK activity after ischemia compared to corresponding normoxic group. Similarly, CNH hearts exhibited increased ischemic level of Akt protein phosphorylated on Ser473. The CNH also strengthened the interaction of HK2 with mitochondria and prevented downregulation of mitochondrial creatine kinase after reperfusion. The Bax/Bcl-2 ratio was significantly lower after I/R in CNH hearts than in normoxic ones, suggesting a lower probability of apoptosis. In conclusion, the Akt/HK2 pathway is likely to play a role in the development of a cardioprotective phenotype of CNH by preventing the detachment of HK2 from mitochondria at reperfusion period and decreases the Bax/Bcl-2 ratio during I/R insult, thereby lowering the probability of apoptosis activation in the mitochondrial compartment.

• Klíčová slova
• Heart, Hexokinase, Hypoxia, Ischemia/reperfusion, Mitochondria, Protein kinase B/Akt,
• MeSH
• hexokinasa metabolismus   MeSH
• krysa rodu Rattus MeSH
• myokard enzymologie   patologie   MeSH
• potkani Wistar MeSH
• protoonkogenní proteiny c-akt metabolismus   MeSH
• reperfuzní poškození myokardu enzymologie   patologie   MeSH
• srdeční mitochondrie enzymologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hexokinasa MeSH
• protoonkogenní proteiny c-akt MeSH