Lentiviral transduction of neonatal rat ventricular myocytes preserves ultrastructural features of genetically modified cells

Virology ◽  
2021 ◽  
Author(s):  
S.R. Consonni ◽  
A.C.P.V. de Carvalho ◽  
B.A. Mauro ◽  
K.G. Franchini ◽  
M.C. Bajgelman
Author(s):  
Tara A Shrout

Cardiac hypertrophy is a growth process that occurs in response to stress stimuli or injury, and leads to the induction of several pathways to alter gene expression. Under hypertrophic stimuli, sarcomeric structure is disrupted, both as a consequence of gene expression and local changes in sarcomeric proteins. Cardiac-restricted ankyrin repeat protein (CARP) is one such protein that function both in cardiac sarcomeres and at the transcriptional level. We postulate that due to this dual nature, CARP plays a key role in maintaining the cardiac sarcomere. GATA4 is another protein detected in cardiomyocytes as important in hypertrophy, as it is activated by hypertrophic stimuli, and directly binds to DNA to alter gene expression. Results of GATA4 activation over time were inconclusive; however, the role of CARP in mediating hypertrophic growth in cardiomyocytes was clearly demonstrated. In this study, Neonatal Rat Ventricular Myocytes were used as a model to detect changes over time in CARP and GATA4 under hypertrophic stimulation by phenylephrine and high serum media. Results were detected by analysis of immunoblotting. The specific role that CARP plays in mediating cellular growth under hypertrophic stimuli was studied through immunofluorescence, which demonstrated that cardiomyocyte growth with hypertrophic stimulation was significantly blunted when NRVMs were co-treated with CARP siRNA. These data suggest that CARP plays an important role in the hypertrophic response in cardiomyocytes.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Adonis Z Wu ◽  
Shien-Fong Lin ◽  
Sheng-Nan Wu

Introduction: Zebrafish heart is established as a model to investigate cardiac electrical abnormalities. However, electrical properties of adult zebrafish cardiomyocytes are not sufficiently characterized. Hypothesis: In this study, by comparing the electrical properties between neonatal rat ventricular myocytes (NRVMs) and adult zebrafish ventricular myocytes (AZVMs), we intended to characterize the action potential (AP), action current (AC) and the properties of Na + current ( I Na ) in AZVMs. Methods: We used patch-clamp technique to characterize the electrical properties, including AP, AC and I Na , in cultured NRVMs and freshly isolated AZVMs. Results: NVRMs showed larger AP amplitude (119±6 vs. 79±4mV, p<.05) but shorter AP duration (APD 90 , 136±11 vs. 213±19 ms, p<.05) than those of AZVMs. The AP duration exhibited marked frequency-dependent alterations in AZVMs. Under the slow pacing rate, early after-depolarizations (EAD) emerged under slow pacing rate with 0.05 Hz. In cell-attached voltage-clamp recordings made from AZVMs, ACs could be elicited by +10 mV steps. As the depolarization step increased to +70 mV, the latency for appearance of ACs was progressively reduced from >123 ms to 9.8 ms. The presence of spontaneous ACs was monitored in spontaneously beating NRVMs and AZVMs. The AC amplitude in NRVMs was larger compared to that in AZVMs (17.3±2.1 vs. 11.6±1.1 pA, p<.05), although firing frequency of AC in NRVMs is higher than in AZVMs (1.13±0.09 vs. 0.38±0.03 Hz, p<.05). The lowering effect of ranolazine, a I Na antagonist, on firing frequency was significantly larger in NRVMs (1.13±0.09 to 0.31±0.02 Hz, p<.05) than in AZVMs (0.38±0.03 to 0.27±0.02 Hz). There was a hyperpolarizing shift of peak I Na in AZVM compared to NRVM. Conclusions: Our results demonstrated major differences in the cellular electrical behavior between AZVMs and NRVMs.


2006 ◽  
Vol 46 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Ilka Lorenzen-Schmidt ◽  
Geert W. Schmid-Schönbein ◽  
Wayne R. Giles ◽  
Andrew D. McCulloch ◽  
Shu Chien ◽  
...  

2013 ◽  
Vol 142 (4) ◽  
pp. 425-436 ◽  
Author(s):  
Guillaume Calmettes ◽  
Scott A. John ◽  
James N. Weiss ◽  
Bernard Ribalet

In mammalian tumor cell lines, localization of hexokinase (HK) isoforms to the cytoplasm or mitochondria has been shown to control their anabolic (glycogen synthesis) and catabolic (glycolysis) activities. In this study, we examined whether HK isoform differences could explain the markedly different metabolic profiles between normal adult and neonatal cardiac tissue. We used a set of novel genetically encoded optical imaging tools to track, in real-time in isolated adult (ARVM) and neonatal (NRVM) rat ventricular myocytes, the subcellular distributions of HKI and HKII, and the functional consequences on glucose utilization. We show that HKII, the predominant isoform in ARVM, dynamically translocates from mitochondria and cytoplasm in response to removal of extracellular glucose or addition of iodoacetate (IAA). In contrast, HKI, the predominant isoform in NRVM, is only bound to mitochondria and is not displaced by the above interventions. In ARVM, overexpression of HKI, but not HKII, increased glycolytic activity. In neonatal rat ventricular myocytes (NVRM), knockdown of HKI, but not HKII, decreased glycolytic activity. In conclusion, differential interactions of HKI and HKII with mitochondria underlie the different metabolic profiles of ARVM and NRVM, accounting for the markedly increased glycolytic activity of NRVM.


2000 ◽  
Vol 278 (4) ◽  
pp. H1211-H1217 ◽  
Author(s):  
Roby D. Rakhit ◽  
Richard J. Edwards ◽  
James W. Mockridge ◽  
Anwar R. Baydoun ◽  
Amanda W. Wyatt ◽  
...  

The aim of this study was to investigate the role of nitric oxide (NO) in a cellular model of early preconditioning (PC) in cultured neonatal rat ventricular myocytes. Cardiomyocytes “preconditioned” with 90 min of stimulated ischemia (SI) followed by 30 min reoxygenation in normal culture conditions were protected against subsequent 6 h of SI. PC was blocked by N G-monomethyl-l-arginine monoacetate but not by dexamethasone pretreatment. Inducible nitric oxide synthase (NOS) protein expression was not detected during PC ischemia. Pretreatment (90 min) with the NO donor S-nitroso- N-acetyl-l,l-penicillamine (SNAP) mimicked PC, resulting in significant protection. SNAP-triggered protection was completely abolished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) but was unaffected by chelerythrine or the presence of glibenclamide and 5-hydroxydecanoate. With the use of RIA, SNAP treatment increased cGMP levels, which were blocked by ODQ. Hence, NO is implicated as a trigger in this model of early PC via activation of a constitutive NOS isoform. After exposure to SNAP, the mechanism of cardioprotection is cGMP dependent but independent of protein kinase C or ATP-sensitive K+ channels. This differs from the proposed mechanism of NO-induced cardioprotection in late PC.


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