Influence of Ischemic Pre- and Post-Conditioning on Cardiac Expression of Calcium-Sensing Receptor

© 2016, Springer Science+Business Media New York.Ischemic heart disease is a common cause of patients’ death worldwide. Recently, cardiac pre- and post-conditioning (IPC, IPoC) were indentified to reduce infarct size. Nevertheless, not only infarct size but also post-infarct remodelling is critical for the long-term enhancing effect. Calcium-sensing receptors (CaSRs) signalling was shown to be involved in IPC and IPoC in the heart. This study aims to clarify CaSRs expression after ischemia-reperfusion injury (I/R), IPC and IPoC. Experiments were performed on adult Wistar rats with left anterior descending coronary artery (LAD) occlusion. Troponin I (TnI) levels were measured in plasma of all animals to quantify the infarct size. Sham-operated animals, rats with I/R, IPC, and IPoC were compared. Left and right ventricular tissue samples from these groups were collected for qRT-PCR analysis. CaSR expression was enhanced in rats with I/R and IPC. Its increase after IPoC was not pronounced. In contrast, left ventricles (LV) showed decreased CaSR expression in rat hearts after I/R, IPC, and IPoC. Data suggest differences in CaSR regulation between LV and RV. Enhanced CaSR expression in RV was observed in tissue with small infarct size

Mechanisms by which calcium receptor stimulation modifies electromechanical coupling in isolated ventricular cardiomyocytes

The calcium-sensing receptor (CaR) is widely expressed throughout the entire cardiovascular system and is capable of activating signaling pathways in different cells. Alongside calcium, the CaR also responds to physiological polycations such as putrescine underlining a participation in physiological and pathophysiological processes. Here, we aimed to determine mechanisms as to how CaR activation affects the contractile responsiveness of ventricular cardiomyocytes under basal and stimulated conditions. For that purpose, cardiac myocytes from 3-month-old male Wistar rats were isolated, and the acute effects of an antagonist (NPS2390), agonists (putrescine and gadolinium), or of downregulation of the CaR by siRNA on cell shortening were recorded in a cell-edge-detection system. In addition, experiments were performed on muscle stripes and Langendorff preparations. Mechanistic insights were taken from calcium transients of beating fura-2 AM-loaded cardiomyocytes and western blots. Isolated ventricular cardiomyocytes constitutively express CaR. The expression in the atria is less pronounced. Acute inhibition of CaR reduced basal cell shortening of ventricular myocytes at nearly physiological levels of extracellular calcium. Inhibition of CaR strongly reduced contractility of ventricular muscle stripes but not of atria. Activation of CaR by putrescine and gadolinium influences the contractile responsiveness of isolated cardiomyocytes. Increased calcium mobilization from the sarcoplasmic reticulum via an IP3-dependent mechanism was responsible for amplified systolic calcium transients and a subsequent improvement in cell shortening. Alongside with these effects, activation of CaR increased relaxation velocity of the cells. In conclusion, ventricular CaR expression affects contractile parameters of ventricular heart muscle cells and modifies electromechanical coupling of cardiomyocytes. © 2014 Springer-Verlag Berlin Heidelberg

The Role of Calcium-Sensing Receptors in Endothelin-1-Dependent Effects on Adult Rat Ventricular Cardiomyocytes: Possible Contribution to Adaptive Myocardial Hypertrophy

© 2016 Wiley Periodicals, Inc.Nitric oxide (NO)-deficiency as it occurs during endothelial dysfunction activates the endothelin-1 (ET-1) system and increases the expression of receptor activity modifying protein (RAMP)-1 that acts as a chaperon for calcium-sensing receptors (CaR) that have recently been identified to improve cardiac function. Here, we hypothesized that ET-1 increases the cardiac expression of CaR and thereby induces an adaptive type of hypertrophy. Expressions of RAMP-1, endothelin receptors, and CaR were analyzed by RT-PCR in left ventricular tissues of L-NAME-treated rats. Effects of ET-1 on CaR expression and cell function (load free cell shortening) were analyzed in adult rat ventricular cardiomyocytes. siRNA directed against CaR and RAMP-1 was used to investigate a causal relationship. PD142893 and BQ788 were used to dissect the contribution of ETB1, ETB2, and ETA receptors. Non-specific NO synthase inhibition with L-Nitro arginine methyl ester (L-NAME) caused a cardiac upregulation of ETB receptors and CaR suggesting a paracrine effect of ET-1 on cardiomyocytes. Indeed, ET-1 induced the expression of CaR in cultured cardiomyocytes. Under these conditions, cardiomyocytes increased cell size (hypertrophy) but maintained normal function. Inhibition of ETA and ETB1 receptors led to ET-1-dependent reduction in cell shortening and attenuated up-regulation of CaR. Down-regulation of RAMP-1 reduced CaR responsiveness. In conclusion, ET-1 causes an adaptive type of hypertrophy by up-regulation of CaR in cardiomyocytes via ETA and/or ETB1 receptors. J. Cell. Physiol. 232: 2508–2518, 2017. © 2016 Wiley Periodicals, Inc

Endothelial PlexinD1 signaling instructs spinal cord vascularization and motor neuron development

How the vascular and neural compartment cooperate to achieve such a complex and highly specialized structure as the central nervous system is still unclear. Here, we reveal a crosstalk between motor neurons (MNs) and endothelial cells (ECs), necessary for the coordinated development of MNs. By analyzing cell-to-cell interaction profiles of the mouse developing spinal cord, we uncovered semaphorin 3C (Sema3C) and PlexinD1 as a communication axis between MNs and ECs. Using cell-specific knockout mice and in vitro assays, we demonstrate that removal of Sema3C in MNs, or its receptor PlexinD1 in ECs, results in premature and aberrant vascularization of MN columns. Those vascular defects impair MN axon exit from the spinal cord. Impaired PlexinD1 signaling in ECs also causes MN maturation defects at later stages. This study highlights the importance of a timely and spatially controlled communication between MNs and ECs for proper spinal cord development

Influence of Ischemic Pre- and Post-Conditioning on Cardiac Expression of Calcium-Sensing Receptor

© 2016, Springer Science+Business Media New York.Ischemic heart disease is a common cause of patients’ death worldwide. Recently, cardiac pre- and post-conditioning (IPC, IPoC) were indentified to reduce infarct size. Nevertheless, not only infarct size but also post-infarct remodelling is critical for the long-term enhancing effect. Calcium-sensing receptors (CaSRs) signalling was shown to be involved in IPC and IPoC in the heart. This study aims to clarify CaSRs expression after ischemia-reperfusion injury (I/R), IPC and IPoC. Experiments were performed on adult Wistar rats with left anterior descending coronary artery (LAD) occlusion. Troponin I (TnI) levels were measured in plasma of all animals to quantify the infarct size. Sham-operated animals, rats with I/R, IPC, and IPoC were compared. Left and right ventricular tissue samples from these groups were collected for qRT-PCR analysis. CaSR expression was enhanced in rats with I/R and IPC. Its increase after IPoC was not pronounced. In contrast, left ventricles (LV) showed decreased CaSR expression in rat hearts after I/R, IPC, and IPoC. Data suggest differences in CaSR regulation between LV and RV. Enhanced CaSR expression in RV was observed in tissue with small infarct size

Influence of Ischemic Pre- and Post-Conditioning on Cardiac Expression of Calcium-Sensing Receptor

© 2016, Springer Science+Business Media New York.Ischemic heart disease is a common cause of patients’ death worldwide. Recently, cardiac pre- and post-conditioning (IPC, IPoC) were indentified to reduce infarct size. Nevertheless, not only infarct size but also post-infarct remodelling is critical for the long-term enhancing effect. Calcium-sensing receptors (CaSRs) signalling was shown to be involved in IPC and IPoC in the heart. This study aims to clarify CaSRs expression after ischemia-reperfusion injury (I/R), IPC and IPoC. Experiments were performed on adult Wistar rats with left anterior descending coronary artery (LAD) occlusion. Troponin I (TnI) levels were measured in plasma of all animals to quantify the infarct size. Sham-operated animals, rats with I/R, IPC, and IPoC were compared. Left and right ventricular tissue samples from these groups were collected for qRT-PCR analysis. CaSR expression was enhanced in rats with I/R and IPC. Its increase after IPoC was not pronounced. In contrast, left ventricles (LV) showed decreased CaSR expression in rat hearts after I/R, IPC, and IPoC. Data suggest differences in CaSR regulation between LV and RV. Enhanced CaSR expression in RV was observed in tissue with small infarct size

Influence of Ischemic Pre- and Post-Conditioning on Cardiac Expression of Calcium-Sensing Receptor

© 2016, Springer Science+Business Media New York.Ischemic heart disease is a common cause of patients’ death worldwide. Recently, cardiac pre- and post-conditioning (IPC, IPoC) were indentified to reduce infarct size. Nevertheless, not only infarct size but also post-infarct remodelling is critical for the long-term enhancing effect. Calcium-sensing receptors (CaSRs) signalling was shown to be involved in IPC and IPoC in the heart. This study aims to clarify CaSRs expression after ischemia-reperfusion injury (I/R), IPC and IPoC. Experiments were performed on adult Wistar rats with left anterior descending coronary artery (LAD) occlusion. Troponin I (TnI) levels were measured in plasma of all animals to quantify the infarct size. Sham-operated animals, rats with I/R, IPC, and IPoC were compared. Left and right ventricular tissue samples from these groups were collected for qRT-PCR analysis. CaSR expression was enhanced in rats with I/R and IPC. Its increase after IPoC was not pronounced. In contrast, left ventricles (LV) showed decreased CaSR expression in rat hearts after I/R, IPC, and IPoC. Data suggest differences in CaSR regulation between LV and RV. Enhanced CaSR expression in RV was observed in tissue with small infarct size

The Role of Calcium-Sensing Receptors in Endothelin-1-Dependent Effects on Adult Rat Ventricular Cardiomyocytes: Possible Contribution to Adaptive Myocardial Hypertrophy

© 2016 Wiley Periodicals, Inc.Nitric oxide (NO)-deficiency as it occurs during endothelial dysfunction activates the endothelin-1 (ET-1) system and increases the expression of receptor activity modifying protein (RAMP)-1 that acts as a chaperon for calcium-sensing receptors (CaR) that have recently been identified to improve cardiac function. Here, we hypothesized that ET-1 increases the cardiac expression of CaR and thereby induces an adaptive type of hypertrophy. Expressions of RAMP-1, endothelin receptors, and CaR were analyzed by RT-PCR in left ventricular tissues of L-NAME-treated rats. Effects of ET-1 on CaR expression and cell function (load free cell shortening) were analyzed in adult rat ventricular cardiomyocytes. siRNA directed against CaR and RAMP-1 was used to investigate a causal relationship. PD142893 and BQ788 were used to dissect the contribution of ETB1, ETB2, and ETA receptors. Non-specific NO synthase inhibition with L-Nitro arginine methyl ester (L-NAME) caused a cardiac upregulation of ETB receptors and CaR suggesting a paracrine effect of ET-1 on cardiomyocytes. Indeed, ET-1 induced the expression of CaR in cultured cardiomyocytes. Under these conditions, cardiomyocytes increased cell size (hypertrophy) but maintained normal function. Inhibition of ETA and ETB1 receptors led to ET-1-dependent reduction in cell shortening and attenuated up-regulation of CaR. Down-regulation of RAMP-1 reduced CaR responsiveness. In conclusion, ET-1 causes an adaptive type of hypertrophy by up-regulation of CaR in cardiomyocytes via ETA and/or ETB1 receptors. J. Cell. Physiol. 232: 2508–2518, 2017. © 2016 Wiley Periodicals, Inc

The Role of Calcium-Sensing Receptors in Endothelin-1-Dependent Effects on Adult Rat Ventricular Cardiomyocytes: Possible Contribution to Adaptive Myocardial Hypertrophy

© 2016 Wiley Periodicals, Inc.Nitric oxide (NO)-deficiency as it occurs during endothelial dysfunction activates the endothelin-1 (ET-1) system and increases the expression of receptor activity modifying protein (RAMP)-1 that acts as a chaperon for calcium-sensing receptors (CaR) that have recently been identified to improve cardiac function. Here, we hypothesized that ET-1 increases the cardiac expression of CaR and thereby induces an adaptive type of hypertrophy. Expressions of RAMP-1, endothelin receptors, and CaR were analyzed by RT-PCR in left ventricular tissues of L-NAME-treated rats. Effects of ET-1 on CaR expression and cell function (load free cell shortening) were analyzed in adult rat ventricular cardiomyocytes. siRNA directed against CaR and RAMP-1 was used to investigate a causal relationship. PD142893 and BQ788 were used to dissect the contribution of ETB1, ETB2, and ETA receptors. Non-specific NO synthase inhibition with L-Nitro arginine methyl ester (L-NAME) caused a cardiac upregulation of ETB receptors and CaR suggesting a paracrine effect of ET-1 on cardiomyocytes. Indeed, ET-1 induced the expression of CaR in cultured cardiomyocytes. Under these conditions, cardiomyocytes increased cell size (hypertrophy) but maintained normal function. Inhibition of ETA and ETB1 receptors led to ET-1-dependent reduction in cell shortening and attenuated up-regulation of CaR. Down-regulation of RAMP-1 reduced CaR responsiveness. In conclusion, ET-1 causes an adaptive type of hypertrophy by up-regulation of CaR in cardiomyocytes via ETA and/or ETB1 receptors. J. Cell. Physiol. 232: 2508–2518, 2017. © 2016 Wiley Periodicals, Inc