APVV-15-0302

Cytoarchitecture of calcium signalling in cardiac myocytes in the development of myocardial hypertrophy (CAMYS)

Principal Investigator: Alexandra Zahradníková

Duration: July 2016 – June 2019
Coordinating Organization: Institute of Molecular Physiology and Genetics SAS, Bratislava

Annotation:

In early phases of many cardiovascular diseases, calcium signalling deteriorates and cardiomyocyte hypertrophy is activated. Calcium signalling, in addition to control of contractile function, modulates many of signalling pathways and metabolism of myocytes. Therefore, disruption of calcium signalling in either systolic or diastolic phase may be a consequence, but also the cause of the maladaptive reaction of myocytes to overload. We hypothesize that processes related to hypertrophy lead to changes in distribution of endo/sarcoplasmic reticulum elements responsible for calcium signalling and for proteosynthesis, and to associated changes in expression and distribution of calcium signalling proteins. This study aims to determine differences in the myocyte calcium signalling system of myocardium adapting to pathological or physiological load and to compare them with development of the myocyte calcium signalling system during postnatal maturation of myocardium. The status of the calcium signalling system will be analysed in models of myocardial load in laboratory rats: a/ sedentary model – animals in standard cages, b/ model of physiological load – animals in cages with a running wheel, 3/ model of pressure overload – surgical obstruction of ascending aorta, and d/ growth model of hypertrophy – postnatal development of myocardium. State-of-the-art methods of electrophysiology, molecular biology and ultrastructural microscopy will be used to characterize quality and distribution of calcium signals, the extent and distribution of smooth and rough sarcoplasmic reticulum, and of expression, localization and co-localization of calcium signalling proteins. We expect that the multidisciplinary approach supported by the expertise of team members will allow interpreting cellular and molecular mechanisms of calcium signalling and drawing conclusions relevant to understanding mechanisms of heart failure that will aid development of new therapeutic and preventative procedures.

Keywords:

myocardium, hypertrophy, postnatal development, physiological load, pressure overload, cardiac myocyte, calcium signalling, cytoarchitecture, reticular membrane system, protein expression, protein co-localization

Objectives:

The aim of the project is to elucidate the role of molecular and cellular factors of diastolic and systolic calcium signalling during development and in early stages of adaptation of cardiac myocytes to stress stimuli leading to myocardial hypertrophy. The aim will be reached by examining local calcium release in spontaneous and evoked calcium sparks, by examining the activity of single RYR2 and IP3R2 channels and membrane compartment markers and by examining the microarchitecture of the myocytes in experimental models of physiological and pathological myocardial hypertrophy.

Publications:

	Hotka M, Zahradnik I (2017): Reconstruction of membrane current by deconvolution and its application to membrane capacitance measurements in cardiac myocytes. PLoS One 12: e0188452.
	Mackova K, Zahradnikova A Jr, Hotka M, Hoffmannova B, Zahradnik I, Zahradnikova A (2017). Calcium release-dependent inactivation precedes formation of the tubular system in developing rat cardiac myocytes. Eur Biophys J 46: 691-703.
	Faltinova A, Tomaskova N, Antalik M, Sevcik J, Zahradnikova A (2017). The N-terminal region of the ryanodine receptor affects channel activation. Front Physiol 8: 443.
	Misuth M, Joniova J, Horvath D, Dzurova L, Nichtova Z, Novotova M, Miskovsky P, Stroffekova K, Huntosova V. (2017): The flashlights on a distinct role of protein kinase C δ: Phosphorylation of regulatory and catalytic domain upon oxidative stress in glioma cells. Cell Signal 34: 11–22.
	Huntosova V, Novotova M, Nichtova Z, Balogova L, Maslanakova M, Petrovajova D, Stroffekova K (2017): Assessing light-independent effects of hypericin on cell viability, ultrastructure and metabolism in human glioma and endothelial cells. Toxicol In Vitro 40: 184–195.
	Novotova M, Tarabova B, Tylkova L, Ventura-Clapier R, Zahradnik I (2016): Ultrastructural remodelling of slow skeletal muscle fibres in creatine kinase deficient mice: a quantitative study. Gen Physiol Biophys 35: 477–486.