Oxidative stress and decline in cellular redox regulation have been hypothesized to play a key role in cardiovascular aging; however, data on antioxidant and redox regulating systems in the aging heart are controversial. The aim of the present study was to examine the effect of aging on critical antioxidant enzymes and two major redox-regulatory systems glutathione (GSH) and thioredoxin (Trx) system in hearts from adult (6-month-old), old (15-month-old), and senescent (26-month-old) rats. Aging was associated with a non-uniform array of changes, including decline in contents of reduced GSH and total mercaptans in the senescent heart. The activities of Mn-superoxide dismutase (SOD2), glutathione peroxidase (GPx), glutathione reductase (GR), and thioredoxin reductase (TrxR) exhibited an age-related decline, whereas catalase was unchanged and Cu,Zn-superoxide dismutase (SOD1) displayed only slight decrease in old heart and was unchanged in the senescent heart. GR, Trx, and peroxiredoxin levels were significantly reduced in old and/or senescent hearts, indicating a diminished expression of these proteins. In contrast, SOD2 level was unchanged in the old heart and was slightly elevated in the senescent heart. Decline in GPx activity was accompanied by a loss of GPx level only in old rats, the level in senescent heart was unchanged. These results indicate age-related posttranslational protein modification of SOD2 and GPx. In summary, our data suggest that changes are more pronounced in senescent than in old rat hearts and support the view that aging is associated with disturbed redox balance that could alter cellular signaling and regulation.
- MeSH
- antioxidancia analýza metabolismus MeSH
- glutathionperoxidasa analýza metabolismus MeSH
- krysa rodu rattus MeSH
- myokard chemie enzymologie MeSH
- oxidace-redukce MeSH
- potkani Wistar MeSH
- stárnutí metabolismus MeSH
- superoxiddismutasa metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Reduced tolerance to ischemia/reperfusion (IR) injury has been shown in elder human and animal hearts, however, the onset of this unfavorable phenotype and cellular mechanisms behind remain unknown. Moreover, aging may interfere with the mechanisms of innate cardioprotection (preconditioning, PC) and cause defects in protective cell signaling. We studied the changes in myocardial function and response to ischemia, as well as selected proteins involved in "pro-survival" pathways in the hearts from juvenile (1.5 months), younger adult (3 months) and mature adult (6 months) male Wistar rats. In Langendorff-perfused hearts exposed to 30-min ischemia/2-h reperfusion with or without prior PC (one cycle of 5-min ischemia/5-min reperfusion), we measured occurrence of reperfusion-induced arrhythmias, recovery of contractile function (left ventricular developed pressure, LVDP, in % of pre-ischemic values), and size of infarction (IS, in % of area at risk size, TTC staining and computerized planimetry). In parallel groups, LV tissue was sampled for the detection of protein levels (WB) of Akt kinase (an effector of PI3-kinase), phosphorylated (activated) Akt (p-Akt), its target endothelial NO synthase (eNOS) and protein kinase Cepsilon (PKCepsilon) as components of "pro-survival" cascades. Maturation did not affect heart function, however, it impaired cardiac response to lethal IR injury (increased IS) and promoted arrhythmogenesis. PC reduced the occurrence of malignant arrhythmias, IS and improved LVDP recovery in the younger animals, while its efficacy was attenuated in the mature adults. Loss of PC protection was associated with age-dependent reduced Akt phosphorylation and levels of eNOS and PKCepsilon in the hearts of mature animals compared with the younger ones, as well as with a failure of PC to upregulate these proteins. Aging-related alterations in myocardial response to ischemia may be caused by dysfunction of proteins involved in protective cell signaling that may occur already during the process of maturation.
- MeSH
- časové faktory MeSH
- fosforylace MeSH
- funkce levé komory srdeční MeSH
- fyziologická adaptace MeSH
- infarkt myokardu metabolismus patologie patofyziologie prevence a kontrola MeSH
- ischemické přivykání metody MeSH
- komorový tlak (srdce) MeSH
- koronární cirkulace MeSH
- modely nemocí na zvířatech MeSH
- myokard metabolismus patologie MeSH
- obnova funkce MeSH
- potkani Wistar MeSH
- preparace izolovaného srdce MeSH
- proteinkinasa C-epsilon metabolismus MeSH
- protoonkogenní proteiny c-akt metabolismus MeSH
- reperfuzní poškození myokardu metabolismus patologie patofyziologie prevence a kontrola MeSH
- signální transdukce MeSH
- srdeční arytmie etiologie patofyziologie prevence a kontrola MeSH
- srdeční frekvence MeSH
- stárnutí metabolismus patologie MeSH
- synthasa oxidu dusnatého, typ III metabolismus MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Publikační typ
- abstrakt z konference MeSH
- MeSH
- extracelulárním signálem regulované MAP kinasy * analýza MeSH
- histologické techniky MeSH
- homocystein * analýza aplikace a dávkování škodlivé účinky MeSH
- hyperhomocysteinemie * chemicky indukované patofyziologie MeSH
- infarkt myokardu * etiologie MeSH
- interpretace statistických dat MeSH
- kardiomyocyty * fyziologie patologie MeSH
- matematické výpočty počítačové MeSH
- mitogenem aktivované proteinkinasy kinas * analýza MeSH
- potkani Wistar MeSH
- srdce fyziologie patofyziologie MeSH
- western blotting metody využití MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Altered Ca(2+) handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca(2+)-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca(2+)-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that age-related alteration in Ca(2+)-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation.
- MeSH
- Ca2+-ATPasy metabolismus MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- myokard enzymologie patologie MeSH
- oxidace-redukce MeSH
- oxidační stres fyziologie MeSH
- potkani Wistar MeSH
- sarkoplazmatické retikulum enzymologie MeSH
- stárnutí patologie fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nové trendy v liečbe rakoviny sa spájajú s rozvojom presne cielených terapeutík, s účinkom na rakovinové bunky a zameraním na špecifické biologické dráhy. Úloha onkoproteínov a tumor-supresorových proteínov v proliferačnej signalizácii, regulácii bunkového cyklu a pozmenenej adhézii je už dobre preskúmaná. Chemické látky, vírusy a žiarenie sú tiež všeobecne prijímanými faktormi, ktoré vyvolávajú mutácie v génoch kódujúcich proteíny súvisiace s tvorbou rakoviny. Nedávne experimenty ukázali, že existujú dva nové kľúčové faktory pôsobiace na proliferujúce bunky – hypoxia a nedostatok glukózy. Tieto môžu iniciovať a podporovať proces malígnej transformácie v malom množstve buniek, ktorým sa podarilo uniknúť bunkovému starnutiu. Neregulovaná bunková proliferácia vedie k tvorbe bunkovej masy presahujúcej svoje rezervy, čo znižuje množstvo kyslíka a živín. Vzniknutý stav hypoxie iniciuje ďalšie kľúčové úpravy, ktoré umožňujú prežitie nádorových buniek. Proces apoptózy je potlačený a metabolizmus glukózy pozmenený. Nedávne experimenty naznačili, že vyčerpanie zásob kyslíka stimuluje mitochondrie, aby spracovávali väčšie množstvá reaktívnych foriem kyslíka (ROS). Aktivujú sa tak signálne dráhy, ako je hypoxiu-indukujúci faktor 1, ktoré podporujú prežívanie nádorových buniek a rast nádorov. Mitochondrie sú čoraz častejšie považované za kľúčové organely podieľajúce sa na chemoterapii, a preto je dôležité nájsť spôsob ako aktivovať apoptózu v mitochondriách za podmienok hypoxie, určiť vzťah medzi mitochondriami, ROS signalizáciou a procesmi aktivujúcimi prežívanie buniek. Každé nové zistenie môže otvoriť cestu pre pochopenie a odhalenie podstaty rakoviny a následné vytvorenie na mieru šitej terapie.
New insights into cancer cells – specific biological pathways are urgently needed to promote development of exactly targeted therapeutics. The role of oncoproteins and tumor suppressor proteins in proliferative signaling, cell cycle regulation and altered adhesion is well established. Chemicals, viruses and radiation are also generally accepted as agents that commonly induce mutations in genes encoding these cancer-inducing proteins, thereby giving rise to cancer. More recent evidence indicates the importance of two additional key factors imposed on proliferating cells – hypoxia and/or lack of glucose. These two additional triggers can initiate and promote the process of malignant transformation, when a low percentage of cells escape cellular senescence. Disregulated cell proliferation leads to formation of cellular masses that extend beyond the resting vasculature, resulting in oxygen and nutrient deprivation. Resulting hypoxia triggers a number of critical adaptations that enable cancer cell survival. The process of apoptosis is suppressed and glucose metabolism is altered. Recent investigations suggest that oxygen depletion stimulates mitochondria to compensate increased reactive oxygen species (ROS). It activates signaling pathways, such as hypoxia-inducible factor 1, that promote cancer cell survival and tumor growth. During the last decade, mitochondria have become key organelles involved in chemotherapy-induced apoptosis. Therefore, the relationship between mitochondria, ROS signaling and activation of survival pathways under hypoxic conditions has been the subject of increased study. Insights into mechanisms involved in ROS signaling may offer novel ways to facilitate discovery of cancer-specific therapies.
- Klíčová slova
- energetický metabolizmus, buněčná transformace,
- MeSH
- buněčná smrt fyziologie účinky léků MeSH
- energetický metabolismus MeSH
- faktor 1 indukovatelný hypoxií MeSH
- glykolýza fyziologie MeSH
- isothiokyanatany farmakologie MeSH
- lidé MeSH
- mitochondrie * metabolismus účinky léků MeSH
- nádorová transformace buněk * MeSH
- nádory * metabolismus patologie MeSH
- oxidativní fosforylace MeSH
- proliferace buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
- MeSH
- aldehydy metabolismus MeSH
- elektronový transportní řetězec metabolismus MeSH
- financování organizované MeSH
- krysa rodu rattus MeSH
- malondialdehyd metabolismus MeSH
- myokard metabolismus MeSH
- oxidační stres MeSH
- peroxidace lipidů MeSH
- potkani Wistar MeSH
- srdeční mitochondrie chemie metabolismus MeSH
- stárnutí metabolismus MeSH
- sulfhydrylové sloučeniny metabolismus MeSH
- transport elektronů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
Dysfunction of mitochondria induced by ischemia is considered to be a key event triggering neuronal cell death after brain ischemia. Here we report the effect of ischemia-reperfusion on mitochondrial protein synthesis and activity of cytochrome c oxidase (EC 1.9.3.1, COX). By performing 4-vessel occlusion model of global brain ischemia, we have observed that 15 min of global ischemia led to the inhibition of COX subunit I (COXI) synthesis to 56 % of control. After 1, 3 and 24 h of reperfusion, COXI synthesis was inhibited to 46, 50 and 72 % of control, respectively. Depressed synthesis of COXI was not a result of either diminished transcription of COXI gene or increased proteolytic degradation of COXI, since both Northern hybridization and Western blotting did not show significant changes in COXI mRNA and protein level. Thus, ischemia-reperfusion affects directly mitochondrial translation machinery. In addition, ischemia in duration of 15 min and consequent 1, 3 and 24 h of reperfusion led to the inhibition of COX activity to 90.3, 80.3, 81.9 and 83.5 % of control, respectively. Based on our data, we suggest that inhibition of COX activity is rather caused by ischemia-induced modification of COX polypeptides than by inhibition of mitochondrial translation.
- MeSH
- časové faktory MeSH
- down regulace MeSH
- financování organizované MeSH
- genetická transkripce MeSH
- ischemie mozku enzymologie komplikace MeSH
- krysa rodu rattus MeSH
- messenger RNA metabolismus MeSH
- mitochondriální proteiny biosyntéza genetika MeSH
- mitochondrie enzymologie MeSH
- modely nemocí na zvířatech MeSH
- mozková kůra enzymologie MeSH
- posttranslační úpravy proteinů MeSH
- potkani Wistar MeSH
- regulace genové exprese enzymů MeSH
- reperfuzní poškození enzymologie etiologie MeSH
- respirační komplex IV biosyntéza genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
