|
|
Myocardial phospholipases A2 and oxidative stress
Závišková, Kristýna ; Míčová, Petra (advisor) ; Chytilová, Anna (referee)
Heart and vascular diseases, in which oxidative stress plays an important role, are the most frequent cause of death in developed countries. Therefore today's researches focus on clarifying signaling pathway and their components that operates in these processes. One of the possible key factors can be phospholipases A2. These enzymes hydrolyze unsaturated fatty acids from C2 position on phospholipids, which easily subject to the oxidative modification due to their double bonds. There are five groups: the secreted, the cytosolic, the calcium independent, the platelet-activating factor acetylhydrolases and the lysosomal phospholipases A2. They differ in the requirement for calcium ions for its activity, molecular weight, position of disulfide bonds and amino acids sequences in the active site. Their main importance is to keep the stability and integrity of cell membranes and produce lipid signaling molecules (free fatty acids, lysophospholipids, eicosanoids). The phospholipases A2 play a dual role during oxidative stress in myocardium. First, they have a positive effect by protecting membranes against oxidative stress due to their higher affinity for removal of peroxidized fatty acids from membrane phospholipids. On the other hand, the phospholipases A2 can also cause destructive effects during...
|
|
|
Role of phospholipases A2 in the mechanism of cardioprotection induced by adaptation to chronic hypoxia
Míčová, Petra ; Novotný, Jiří (advisor) ; Kuda, Ondřej (referee) ; Kazdová, Ludmila (referee)
Cardiovascular diseases, particularly acute myocardial infarction, are the leading causes of death in developed countries including the Czech Republic. One of the ways to increase cardiac resistance against acute ischemia/reperfusion (I/R) injury is adaptation to chronic hypoxia. However, changes at the molecular level associated with this adaptation have still not been fully explored. It is obvious that the myocardial function depends on maintaining membrane integrity and cellular homeostasis of cardiomyocytes. From this perspective, phospholipases A2 (PLA2) are the key enzymes that take part in the remodeling and repairing of the cell membranes. Moreover, PLA2 are also involved in generation of lipid signaling molecules - free long chain fatty acids (FA) and 2-lysophopholipids. In myocardium, members of three major PLA2 classes are present: cytosolic PLA2 (cPLA2), calcium-independent PLA2 (iPLA2) and secretoric PLA2 (sPLA2). This thesis aimed to determine the following in the left ventricular myocardium of adult male Wistar rats: 1) The effect of intermittent hypobaric hypoxia (IHH; 8 hours/day, 5 days/week, 5 weeks, ~ 7000 m) on the expression of total cPLA2α and its phosphorylated form (p-cPLA2α, Ser505 ), and further iPLA2 and sPLA2IIA, as well as signaling proteins activating cPLA2α enzyme...
|
|
|
Role of phospholipases A2 in the mechanism of cardioprotection induced by adaptation to chronic hypoxia
Míčová, Petra
Cardiovascular diseases, particularly acute myocardial infarction, are the leading causes of death in developed countries including the Czech Republic. One of the ways to increase cardiac resistance against acute ischemia/reperfusion (I/R) injury is adaptation to chronic hypoxia. However, changes at the molecular level associated with this adaptation have still not been fully explored. It is obvious that the myocardial function depends on maintaining membrane integrity and cellular homeostasis of cardiomyocytes. From this perspective, phospholipases A2 (PLA2) are the key enzymes that take part in the remodeling and repairing of the cell membranes. Moreover, PLA2 are also involved in generation of lipid signaling molecules - free long chain fatty acids (FA) and 2-lysophopholipids. In myocardium, members of three major PLA2 classes are present: cytosolic PLA2 (cPLA2), calcium-independent PLA2 (iPLA2) and secretoric PLA2 (sPLA2). This thesis aimed to determine the following in the left ventricular myocardium of adult male Wistar rats: 1) The effect of intermittent hypobaric hypoxia (IHH; 8 hours/day, 5 days/week, 5 weeks, ~ 7000 m) on the expression of total cPLA2α and its phosphorylated form (p-cPLA2α, Ser505 ), and further iPLA2 and sPLA2IIA, as well as signaling proteins activating cPLA2α enzyme...
|
|
|
Role of phospholipases A2 in the mechanism of cardioprotection induced by adaptation to chronic hypoxia
Míčová, Petra
Cardiovascular diseases, particularly acute myocardial infarction, are the leading causes of death in developed countries including the Czech Republic. One of the ways to increase cardiac resistance against acute ischemia/reperfusion (I/R) injury is adaptation to chronic hypoxia. However, changes at the molecular level associated with this adaptation have still not been fully explored. It is obvious that the myocardial function depends on maintaining membrane integrity and cellular homeostasis of cardiomyocytes. From this perspective, phospholipases A2 (PLA2) are the key enzymes that take part in the remodeling and repairing of the cell membranes. Moreover, PLA2 are also involved in generation of lipid signaling molecules - free long chain fatty acids (FA) and 2-lysophopholipids. In myocardium, members of three major PLA2 classes are present: cytosolic PLA2 (cPLA2), calcium-independent PLA2 (iPLA2) and secretoric PLA2 (sPLA2). This thesis aimed to determine the following in the left ventricular myocardium of adult male Wistar rats: 1) The effect of intermittent hypobaric hypoxia (IHH; 8 hours/day, 5 days/week, 5 weeks, ~ 7000 m) on the expression of total cPLA2α and its phosphorylated form (p-cPLA2α, Ser505 ), and further iPLA2 and sPLA2IIA, as well as signaling proteins activating cPLA2α enzyme...
|
|
|
Role of phospholipases A2 in the mechanism of cardioprotection induced by adaptation to chronic hypoxia
Míčová, Petra ; Novotný, Jiří (advisor) ; Kuda, Ondřej (referee) ; Kazdová, Ludmila (referee)
Cardiovascular diseases, particularly acute myocardial infarction, are the leading causes of death in developed countries including the Czech Republic. One of the ways to increase cardiac resistance against acute ischemia/reperfusion (I/R) injury is adaptation to chronic hypoxia. However, changes at the molecular level associated with this adaptation have still not been fully explored. It is obvious that the myocardial function depends on maintaining membrane integrity and cellular homeostasis of cardiomyocytes. From this perspective, phospholipases A2 (PLA2) are the key enzymes that take part in the remodeling and repairing of the cell membranes. Moreover, PLA2 are also involved in generation of lipid signaling molecules - free long chain fatty acids (FA) and 2-lysophopholipids. In myocardium, members of three major PLA2 classes are present: cytosolic PLA2 (cPLA2), calcium-independent PLA2 (iPLA2) and secretoric PLA2 (sPLA2). This thesis aimed to determine the following in the left ventricular myocardium of adult male Wistar rats: 1) The effect of intermittent hypobaric hypoxia (IHH; 8 hours/day, 5 days/week, 5 weeks, ~ 7000 m) on the expression of total cPLA2α and its phosphorylated form (p-cPLA2α, Ser505 ), and further iPLA2 and sPLA2IIA, as well as signaling proteins activating cPLA2α enzyme...
|
|
|
Role of phospholipases A2 in cardioprotection induced by continuous normobaric hypoxia in rat heart
Kyclerová, Eva ; Nováková, Olga (advisor) ; Novotný, Jiří (referee)
Recently, they are examined various means for activating the endogenous signalling pathways leading to increased resistance of the myocardium from ischemic/reperfusion (I/R) injury. One of them is the adaptation to chronic hypoxia, which has been shown to reduce the incidence and severity of ventricular arrhythmias, improves the recovery of postischemic contractile function of the heart and particularly reduces the extent of myocardial infarction. Since the function of the heart depends on the maintenance of membrane integrity of cardiomyocytes there are very important phospholipase A2 (PLA2) which are involved in the repair of cellular membranes. Also they are an important component of the protective signalling pathways because they cleave membrane phospholipids to produce lipid signalling molecules. Elucidate the role of PLA2 and the precise mechanism of action of signalling pathways leading to cardioprotection could be important for the prevention and treatment of cardiovascular diseases. Therefore, in this thesis we examined the influence of continuous normobaric hypoxia (CNH) to the relative representation of cardiac PLA2 (secretory - sPLA2IIA, calcium-independent - iPLA2, cytosolic - cPLA2α and its phosphorylated form - p-cPLA2α), and proteins involved in the activation and phosphorylation of...
|
|
|
Myocardial phospholipases A2 and oxidative stress
Závišková, Kristýna ; Míčová, Petra (advisor) ; Chytilová, Anna (referee)
Heart and vascular diseases, in which oxidative stress plays an important role, are the most frequent cause of death in developed countries. Therefore today's researches focus on clarifying signaling pathway and their components that operates in these processes. One of the possible key factors can be phospholipases A2. These enzymes hydrolyze unsaturated fatty acids from C2 position on phospholipids, which easily subject to the oxidative modification due to their double bonds. There are five groups: the secreted, the cytosolic, the calcium independent, the platelet-activating factor acetylhydrolases and the lysosomal phospholipases A2. They differ in the requirement for calcium ions for its activity, molecular weight, position of disulfide bonds and amino acids sequences in the active site. Their main importance is to keep the stability and integrity of cell membranes and produce lipid signaling molecules (free fatty acids, lysophospholipids, eicosanoids). The phospholipases A2 play a dual role during oxidative stress in myocardium. First, they have a positive effect by protecting membranes against oxidative stress due to their higher affinity for removal of peroxidized fatty acids from membrane phospholipids. On the other hand, the phospholipases A2 can also cause destructive effects during...
|
guest ::
