scholarly journals MicroRNA-204 Is Necessary for Aldosterone-Stimulated T-Type Calcium Channel Expression in Cardiomyocytes

2018 ◽  
Vol 19 (10) ◽  
pp. 2941 ◽  
Author(s):  
Riko Koyama ◽  
Tiphaine Mannic ◽  
Jumpei Ito ◽  
Laurence Amar ◽  
Maria-Christina Zennaro ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Molecular Mechanisms ◽  
Calcium Currents ◽  
Neonatal Rat ◽  
Messenger Rnas ◽  
Screening Assay ◽  
Rat Cardiomyocytes ◽  
Ventricular Cardiomyocytes ◽  
Channel Expression ◽  
Beating Frequency

Activation of the mineralocorticoid receptor (MR) in the heart is considered to be a cardiovascular risk factor. MR activation leads to heart hypertrophy and arrhythmia. In ventricular cardiomyocytes, aldosterone induces a profound remodeling of ion channel expression, in particular, an increase in the expression and activity of T-type voltage-gated calcium channels (T-channels). The molecular mechanisms immediately downstream from MR activation, which lead to the increased expression of T-channels and, consecutively, to an acceleration of spontaneous cell contractions in vitro, remain poorly investigated. Here, we investigated the putative role of a specific microRNA in linking MR activation to the regulation of T-channel expression and cardiomyocyte beating frequency. A screening assay identified microRNA 204 (miR-204) as one of the major upregulated microRNAs after aldosterone stimulation of isolated neonatal rat cardiomyocytes. Aldosterone significantly increased the level of miR-204, an effect blocked by the MR antagonist spironolactone. When miR-204 was overexpressed in isolated cardiomyocytes, their spontaneous beating frequency was significantly increased after 24 h, like upon aldosterone stimulation, and messenger RNAs coding T-channels (CaV3.1 and CaV3.2) were increased. Concomitantly, T-type calcium currents were significantly increased upon miR-204 overexpression. Specifically repressing the expression of miR-204 abolished the aldosterone-induced increase of CaV3.1 and CaV3.2 mRNAs, as well as T-type calcium currents. Finally, aldosterone and miR-204 overexpression were found to reduce REST-NRSF, a known transcriptional repressor of CaV3.2 T-type calcium channels. Our study thus strongly suggests that miR-204 expression stimulated by aldosterone promotes the expression of T-channels in isolated rat ventricular cardiomyocytes, and therefore, increases the frequency of the cell spontaneous contractions, presumably through the inhibition of REST-NRSF protein.

scholarly journals Aldosterone increases T-type calcium channel expression and in vitro beating frequency in neonatal rat cardiomyocytes

2005 ◽  
Vol 67 (2) ◽  
pp. 216-224 ◽  
Author(s):  
N LALEVEE ◽  
M REBSAMEN ◽  
S BARRERELEMAIRE ◽  
E PERRIER ◽  
J NARGEOT ◽  
...  
Keyword(s):  
Calcium Channel ◽  
Neonatal Rat ◽  
Rat Cardiomyocytes ◽  
Neonatal Rat Cardiomyocytes ◽  
Channel Expression ◽  
Beating Frequency

scholarly journals Long-Term and Immediate Effect of Testosterone on Single T-Type Calcium Channel in Neonatal Rat Cardiomyocytes

Endocrinology ◽  
2006 ◽  
Vol 147 (11) ◽  
pp. 5160-5169 ◽  
Author(s):  
Guido Michels ◽  
Fikret Er ◽  
Michael Eicks ◽  
Stefan Herzig ◽  
Uta C. Hoppe
Keyword(s):  
Calcium Channels ◽  
Single Channel ◽  
Heart Diseases ◽  
Calcium Currents ◽  
Neonatal Rat ◽  
Channel Activity ◽  
Open Probability ◽  
Rat Cardiomyocytes ◽  
Single Channel Activity

In the cardiovascular system, T-type calcium channels play an important role for the intracellular calcium homeostasis and spontaneous pacemaker activity and are involved in the progression of structural heart diseases. Androgens influence the cardiovascular physiology and pathophysiology. However, their effect on native T-type calcium currents (ICa,T) remains unclear. To test the chronic effect of testosterone on the cardiac ICa,T, cultured neonatal rat ventricular cardiomyocytes were treated with testosterone (1 nm-10 μm) for 24–30 h. Current measurements were performed after testosterone washout to exclude any acute testosterone effects. Testosterone (100 nm) pretreatment significantly increased whole-cell ICa,T density from 1.26 ± 0.48 pA/pF (n = 8) to 5.06 ± 1.75 pA/pF (n = 7; P < 0.05) and accelerated beating rate. This was attributed to both increased expression levels of the pore-forming subunits Cav3.1 and Cav3.2 and increased T-type single-channel activity. On single-channel level, the increase of the ensemble average current by testosterone vs. time-matched controls was due to an increased availability (58.1 ± 4.2 vs. 21.5 ± 4.0%, P < 0.01) and open probability (2.78 ± 0.29 vs. 0.85 ± 0.23%, P < 0.01). Cotreatment with the selective testosterone receptor antagonist flutamide (10 μm) prevented these chronic testosterone-induced effects. Conversely, acute application of testosterone (10 μm) decreased T-type single-channel activity in testosterone pretreated cells by reducing the open probability (0.78 ± 0.13 vs. 2.91 ± 0.38%, P < 0.01), availability (23.6 ± 3.3 vs. 57.6 ± 4.5%, P < 0.01), and peak current (−20 ± 4 vs. −58 ± 4 fA, P < 0.01). Flutamide (10 μm) did not abolish the testosterone-induced acute block of T-type calcium channels. Our results indicate that long-term testosterone treatment increases, whereas acute testosterone decreases neonatal rat T-type calcium currents. These effects seem to be mediated by a genomic chronic stimulation and a nongenomic acute inhibitory action.

Abstract P215: β3-Adrenergic Receptor Mediated NOS Signaling in Cardiomyocytes

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Vabren L Watts ◽  
Xiaolin Niu ◽  
Karen L Miller ◽  
Lili A Barouch
Keyword(s):  
Molecular Mechanisms ◽  
Pressure Overload ◽  
Fold Increase ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Regulatory Site ◽  
Ventricular Cardiomyocytes ◽  
Unstimulated Control ◽  
Key Factor ◽  
Nos Isoforms

Beta3 -adrenergic receptors play a pivotal role in modulating cardiac function, though their precise role in the heart remains controversial. We have recently demonstrated alterations in Ca 2+ -dependent NOS isoforms and decreased NOS activity in left ventricular tissue of beta3 -/- mice after pressure overload. However, the exact manner in which beta3-AR signaling regulates these isoforms to stimulate NOS activity at the cardiomyocyte level is not well understood. In this study we used a specific beta3-AR agonist, BRL37344 (BRL), to assess the role of beta3-AR in eNOS and nNOS regulation in hypertrophied isolated neonatal rat ventricular cardiomyocytes (NRVM). To induce hypertrophy we pretreated cells with norepinephrine for 72 hours, which resulted in a 70% increase in cell size and a 25% increase in beta3-AR mRNA expression as compared with non-hypertrophied cells, analyzed by immunocytochemistry and real-time PCR. In hypertrophied cardiomyocytes, BRL administration lead to a time-dependent 5-fold increase in NOS activity, measured by the arginine-to-citrulline conversion assay. beta3-activation also caused a 1.5-fold increase in nNOS phosphorylation at positive regulatory site Ser1416, and dephosphorylation of negative regulatory site Ser847 as compared with unstimulated control. NOS activity and nNOS phosphorylation overlapped in time. In addition BRL induced phosphorylation eNOS-Ser114, which indicates eNOS deactivation. Pretreatment with pertussis toxin (PTX) suppressed BRL-induced nNOS-Ser1416 phosphorylation, nNOS-Ser847 dephosphorylation, and NOS activity, suggesting G i/o dependency. Taken together, our data suggest that BRL regulates NOS signaling in ventricular cardiomyocytes via phosphorylation regulation of nNOS. To our knowledge this is first study to demonstrate a role for nNOS phosphorylation as a key factor in beta3-AR signaling. These results contribute significantly to our understanding the negative inotropic properties of myocardial beta3-AR at cellular levels during cardiac sympathetic overstimulation, and will ultimately aid in drug discoveries that target the molecular mechanisms associated heart failure.

scholarly journals Lycopene Inhibits Urotensin-II-Induced Cardiomyocyte Hypertrophy in Neonatal Rat Cardiomyocytes

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hung-Hsing Chao ◽  
Li-Chin Sung ◽  
Cheng-Hsien Chen ◽  
Ju-Chi Liu ◽  
Jin-Jer Chen ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Glycogen Synthase ◽  
Activity Level ◽  
Neonatal Rat ◽  
Cardiomyocyte Hypertrophy ◽  
Urotensin Ii ◽  
Rat Cardiomyocytes ◽  
Protein Levels ◽  
Neonatal Rat Cardiomyocytes ◽  
Tensin Homolog

This study investigated how lycopene affected urotensin-II- (U-II-) induced cardiomyocyte hypertrophy and the possible implicated mechanisms. Neonatal rat cardiomyocytes were exposed to U-II (1 nM) either exclusively or following 6 h of lycopene pretreatment (1–10 μM). The lycopene (3–10 μM) pretreatment significantly inhibited the U-II-induced cardiomyocyte hypertrophy, decreased the production of U-II-induced reactive oxygen species (ROS), and reduced the level of NAD(P)H oxidase-4 expression. Lycopene further inhibited the U-II-induced phosphorylation of the redox-sensitive extracellular signal-regulated kinases. Moreover, lycopene treatment prevented the increase in the phosphorylation of serine-threonine kinase Akt and glycogen synthase kinase-3beta (GSK-3β) caused by U-II without affecting the protein levels of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN). However, lycopene increased the PTEN activity level, suggesting that lycopene prevents ROS-induced PTEN inactivation. These findings imply that lycopene yields antihypertrophic effects that can prevent the activation of the Akt/GSK-3βhypertrophic pathway by modulating PTEN inactivation through U-II treatment. Thus, the data indicate that lycopene prevented U-II-induced cardiomyocyte hypertrophy through a mechanism involving the inhibition of redox signaling. These findings provide novel data regarding the molecular mechanisms by which lycopene regulates cardiomyocyte hypertrophy.

Abstract 541: Dyxin/Lmcd1, A Novel LIM Protein, Is Both Necessary And Sufficient For The Induction Of Cardiomyocyte Hypertrophy

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Derk Frank ◽  
Christiane Hanselmann ◽  
Rainer Will ◽  
Hugo A Katus ◽  
Norbert Frey
Keyword(s):  
Cardiac Hypertrophy ◽  
Molecular Mechanisms ◽  
Mrna Level ◽  
Neonatal Rat ◽  
Cardiomyocyte Hypertrophy ◽  
Rat Cardiomyocytes ◽  
Hypertrophic Response ◽  
Lim Protein ◽  
A Genome ◽  
Necessary And Sufficient

Sustained cardiac hypertrophy may lead to heart failure and sudden death. While significant progress has been made in elucidating the underlying molecular mechanisms, it is believed that several molecules that modulate cardiomyocyte growth remain elusive. To identify novel candidates involved in hypertrophic signalling, we conducted a genome-wide screening experiment by subjecting neonatal rat cardiomyocytes (NRCM) to either biomechanical stretch or phenylephrine (PE) stimulation followed by microarray analyses. Among several other molecules (stretch: n=164; PE: n=238), the new LIM protein Dyxin/Lmcd1 was significantly upregulated both by stretch (5.6fold, p<0.001) and PE (2.5 fold, p<0.01). Moreover, Dyxin was markedly induced in hypertrophic hearts of transgenic mice overexpressing the phosphatase calcineurin (3.8fold on mRNA- and 2.9fold on protein level (both p<0.01)). To dissect the putative function of this novel molecule, we adenovirally overexpressed Dyxin in NRCM, which led to marked cellular hypertrophy (1.5fold increase in cell surface area, p<0.001) and induction of ANF (3.8fold, p<0.05). In addition, the calcineurin-responsive gene MCIP1.4 was found upregulated (3.2fold, p<0.001), suggesting that Dyxin activates the calcineurin pathway. In order to test whether Dyxin is also required for cardiomyocyte hypertrophy, we stimulated NRCVM with either PE or stretch and utilized adenovirus-encoded microRNAs to knock down Dyxin (−75% on protein, −85% on mRNA level). While both PE and stretch induced significant hypertrophy (+41% and +48%, p<0.001), the inhibition of Dyxin expression completely blunted the hypertrophic response to both stimuli (p<0.001). Consistently, induction of the “hypertrophic gene program” (including ANF, BNP, and alpha-skeletal actin) was abrogated. Likewise, PE-mediated upregulation of MCIP1.4 expression (7.3fold; p<0.001), was entirely prevented by the knockdown of Dyxin (0.8fold, p=n.s.). We show here that Dyxin, which has not been implicated in hypertrophy before, is significantly upregulated in cardiac hypertrophy. Moreover, it is both necessary and sufficient for cardiomyocyte hypertrophy, and this effect is mediated, at least in part by modulation of calcineurin signalling.

mTOR signaling-related microRNAs as cardiac hypertrophy modulators in high‐volume endurance training

2021 ◽  
Author(s):  
Bruno R.A. Pelozin ◽  
Ursula Paula Reno Soci ◽  
João L. P. Gomes ◽  
Edilamar Menezes Oliveira ◽  
Tiago Fernandes
Keyword(s):  
Protein Expression ◽  
Molecular Mechanisms ◽  
High Volume ◽  
Left Ventricular ◽  
Mtor Signaling ◽  
Neonatal Rat ◽  
Cardiomyocyte Hypertrophy ◽  
Peak Exercise ◽  
Dependent Manner ◽  
Rat Cardiomyocytes

Aerobic exercise training (ET) promotes cardiovascular adaptations, including physiological left ventricular hypertrophy (LVH). However, the molecular mechanisms that underlying these changes are unclear. The study aimed to elucidate specific miRNAs and target genes involved with the Akt/mTOR signaling in high-volume ET-induced LVH. Eight-week-old female Wistar rats were assigned to three groups: sedentary control (SC), trained protocol 1 (P1), and trained protocol 2 (P2). P1 consisted of 60 minutes/day of swimming, 5x/week, for 10 weeks. P2 consisted of the same protocol as P1 until the 8th week; in the 9th week, rats trained 2x/day, and in the 10th week, trained 3x/day. Subsequently, structure and molecular parameters were evaluated in the heart. Trained groups demonstrate higher values to VO2 peak, exercise tolerance, and LVH in a volume-dependent manner. The miRNA-26a-5p levels were higher in P1 and P2 compared to SC group (150±15%, d=1.8; 148±16%, d=1.7; and 100±7%, respectively, P < 0.05). In contrast, miRNA-16-5p levels were lower in P1 and P2 compared to SC group (69±5%, d=2.3, P < 0.01; 37±4%, d=5.6, P < 0.001 and 100±6%, respectively). Additionally, miRNA-16-5p knockdown and miRNA-26a-5p overexpression significantly promoted cardiomyocyte hypertrophy in neonatal rat cardiomyocytes. Both miRNAs were selected, using Diana Tolls bioinformatics website, for acting in the mTOR signaling pathway. The protein expression of Akt, mTOR, p70S6k, and 4E-BP1 were greater in P1 and even more pronounced in P2. Nonetheless, GSK3β protein expression was lower in trained groups. Together, these molecular changes may contribute to a pronounced physiological LVH observed in high-volume aerobic training.

Modulation of CaV2.3 Calcium Channel Currents by Eugenol

2008 ◽  
Vol 87 (2) ◽  
pp. 137-141 ◽  
Author(s):  
G. Chung ◽  
J.N. Rhee ◽  
S.J. Jung ◽  
J.S. Kim ◽  
S.B. Oh
Keyword(s):  
Calcium Channels ◽  
Calcium Channel ◽  
Analgesic Effect ◽  
Molecular Mechanisms ◽  
Expression System ◽  
Calcium Currents ◽  
Analgesic Agent ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Channel Currents

Eugenol, a natural congener of capsaicin, is a routine analgesic agent in dentistry. We have recently demonstrated the inhibition of CaV2.2 calcium channel and sodium channel currents to be molecular mechanisms underlying the analgesic effect of eugenol. We hypothesized that CaV2.3 channels are also modulated by eugenol and investigated its mode of action using the whole-cell patch-clamp technique in a heterologous expression system. Eugenol inhibited calcium currents in the E52 cell line, stably expressing the human CaV2.3 calcium channels, where TRPV1 is not endogenously expressed. The extent of current inhibition was not significantly different between naïve E52 cells and TRPV1-expressing E52 cells, suggesting no involvement of TRPV1. In contrast, TRPV1 activation is prerequisite for the inhibition of CaV2.3 calcium channels by capsaicin. The results indicate that eugenol has mechanisms distinct from those of capsaicin for modulating CaV2.3 channels. We suggest that inhibition of CaV2.3 channels by eugenol might contribute to its analgesic effect.

scholarly journals Notch1 signaling stimulates proliferation of immature cardiomyocytes

2008 ◽  
Vol 183 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Chiara Collesi ◽  
Lorena Zentilin ◽  
Gianfranco Sinagra ◽  
Mauro Giacca
Keyword(s):  
Notch Signaling ◽  
Cardiac Myocytes ◽  
Molecular Mechanisms ◽  
Notch Pathway ◽  
Constitutive Expression ◽  
Neonatal Rat ◽  
Proliferative Potential ◽  
Rat Cardiomyocytes

The identification of the molecular mechanisms controlling cardiomyocyte proliferation during the embryonic, fetal, and early neonatal life appears of paramount interest in regard to exploiting this information to promote cardiac regeneration. Here, we show that the proliferative potential of neonatal rat cardiomyocytes is powerfully stimulated by the sustained activation of the Notch pathway. We found that Notch1 is expressed in proliferating ventricular immature cardiac myocytes (ICMs) both in vitro and in vivo, and that the number of Notch1-positive cells in the heart declines with age. Notch1 expression in ICMs paralleled the expression of its Jagged1 ligand on non-myocyte supporting cells. The inhibition of Notch signaling in ICMs blocked their proliferation and induced apoptosis; in contrast, its activation by Jagged1 or by the constitutive expression of its activated form using an adeno-associated virus markedly stimulated proliferative signaling and promoted ICM expansion. Maintenance or reactivation of Notch signaling in cardiac myocytes might represent an interesting target for innovative regenerative therapy.

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