BACKGROUND/AIMS: Hexokinase (HK) is a key glycolytic enzyme which promotes the maintenance of glucose homeostasis in cardiomyocytes. HK1 isoform is predominantly bound to the outer mitochondrial membrane and highly supports oxidative phosphorylation by increasing the availability of ADP for complex V of the respiratory chain. HK2 isoform is under physiological conditions predominantly localized in the cytosol and upon stimulation of PI3K/ Akt pathway associates with mitochondria and thus can prevent apoptosis. The purpose of this study was to investigate expression and subcellular localization of both HK isoforms in left (LV) and right (RV) heart ventricles of adult male Wistar rats. METHODS: Real-Time RT-PCR, Western blotting, and quantitative immunofluorescence microscopy were used. RESULTS: Our results showed a significantly higher expression of both HK1 and HK2 at mRNA and protein levels in the RV compared to the LV. These findings were corroborated by immunofluorescence staining which revealed substantially higher fluorescence signals of both HKs in the RV than in the LV. The ratios of phospho-Ser473-Akt/non-phospho-Akt and phospho-Thr308-Akt/non-phospho-Akt were also markedly higher in the RV than in the LV. CONCLUSION: These results suggest that the RV has a higher activity of aerobic glycolytic metabolism and may be able to respond faster and more powerfully to stressful stimuli than the LV.
BACKGROUND/AIMS: Hexokinase (HK) is a key glycolytic enzyme which promotes the maintenance of glucose homeostasis in cardiomyocytes. HK1 isoform is predominantly bound to the outer mitochondrial membrane and highly supports oxidative phosphorylation by increasing the availability of ADP for complex V of the respiratory chain. HK2 isoform is under physiological conditions predominantly localized in the cytosol and upon stimulation of PI3K/ Akt pathway associates with mitochondria and thus can prevent apoptosis. The purpose of this study was to investigate expression and subcellular localization of both HK isoforms in left (LV) and right (RV) heart ventricles of adult male Wistar rats. METHODS: Real-Time RT-PCR, Western blotting, and quantitative immunofluorescence microscopy were used. RESULTS: Our results showed a significantly higher expression of both HK1 and HK2 at mRNA and protein levels in the RV compared to the LV. These findings were corroborated by immunofluorescence staining which revealed substantially higher fluorescence signals of both HKs in the RV than in the LV. The ratios of phospho-Ser473-Akt/non-phospho-Akt and phospho-Thr308-Akt/non-phospho-Akt were also markedly higher in the RV than in the LV. CONCLUSION: These results suggest that the RV has a higher activity of aerobic glycolytic metabolism and may be able to respond faster and more powerfully to stressful stimuli than the LV.
Authors: David Kolar; Milada Gresikova; Petra Waskova-Arnostova; Barbara Elsnicova; Jana Kohutova; Daniela Hornikova; Pavel Vebr; Jan Neckar; Tereza Blahova; Dita Kasparova; Jiri Novotny; Frantisek Kolar; Olga Novakova; Jitka M Zurmanova Journal: Mol Cell Biochem Date: 2017-03-13 Impact factor: 3.396
Authors: Klara Hahnova; Iveta Brabcova; Jan Neckar; Romana Weissova; Anna Svatonova; Olga Novakova; Jitka Zurmanova; Martin Kalous; Jan Silhavy; Michal Pravenec; Frantisek Kolar; Jiri Novotny Journal: J Physiol Sci Date: 2017-05-31 Impact factor: 2.781