scholarly journals CXCR7 ameliorates myocardial infarction as a β-arrestin-biased receptor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masato Ishizuka ◽  
Mutsuo Harada ◽  
Seitaro Nomura ◽  
Toshiyuki Ko ◽  
Yuichi Ikeda ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Protective Role ◽  
Neonatal Rat ◽  
Border Zone ◽  
Sequencing Analysis ◽  
Rat Cardiomyocytes ◽  
Transmembrane Receptors ◽  
Intracellular Signals ◽  
Extracellular Signal ◽  
And Control

AbstractMost seven transmembrane receptors (7TMRs) are G protein-coupled receptors; however, some 7TMRs evoke intracellular signals through β-arrestin as a biased receptor. As several β-arrestin-biased agonists have been reported to be cardioprotective, we examined the role of the chemokine receptor CXCR7 as a β-arrestin-biased receptor in the heart. Among 510 7TMR genes examined, Cxcr7 was the most abundantly expressed in the murine heart. Single-cell RNA-sequencing analysis revealed that Cxcr7 was abundantly expressed in cardiomyocytes and fibroblasts. Cardiomyocyte-specific Cxcr7 null mice showed more prominent cardiac dilatation and dysfunction than control mice 4 weeks after myocardial infarction. In contrast, there was no difference in cardiac phenotypes between fibroblast-specific Cxcr7-knockout mice and control mice even after myocardial infarction. TC14012, a specific agonist of CXCR7, significantly recruited β-arrestin to CXCR7 in CXCR7-expressing cells and activated extracellular signal-regulated kinase (ERK) in neonatal rat cardiomyocytes. Cxcr7 expression was significantly increased and ERK was activated in the border zone of the heart in control, but not Cxcr7 null mice. These results indicate that the abundantly expressed CXCR7 in cardiomyocytes may play a protective role in the heart as a β-arrestin-biased receptor and that CXCR7 may be a novel therapeutic target for myocardial infarction.

Abstract 855: Circulating Mesoangioblasts Differentiate Into Cardiac Myocytes And Improve Function After Acute Myocardial Infarction

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Masayoshi Iwasaki ◽  
Masamichi Koyanagi ◽  
Stefan Rapp ◽  
Corina Schuetz ◽  
Philipp Bushoven ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Troponin T ◽  
Marker Gene ◽  
Left Ventricular ◽  
Cardiac Differentiation ◽  
Neonatal Rat ◽  
Stem Cell Markers ◽  
Rt Pcr ◽  
Rat Cardiomyocytes

Mesoangioblasts (MAB) are vessel-associated cells identified during embryonic development. In contrast to hemangioblasts, MAB express mesenchymal (CD73) and endothelial marker, but lack the hematopoietic marker CD45. We recently identified circulating MAB in children. Children-derived MAB showed vigorous proliferation capacity and high telomerase activity. However, the potential of cardiac differentiation in these cells was not elucidated. Therefore, we tested the capacity of children-derived MAB to aquire a cardiomyogenic phenotype. MAB expressed several cardiac transcription factors such as Nkx2.5, GATA4 and MEF2C and the stem cell markers c-kit and islet-1. In order to assess cardiac differentiation capacity, we performed co-culture assays with neonatal rat cardiomyocytes (CM). Immunochemical analysis revealed that MAB expressed cardiac α-sarcomeric actinin 6 days after co-culture. Moreover, human troponin T (TnT) was expressed as demonstrated by human specific RT-PCR. To confirm these data, we examined TnT expression in MAB isolated of a 2 years old patient with a known mutation of TnT. Sequences of the cloned RT-PCR products were identical to human TnT except for the known mutation providing genetic proof of concept for cardiac differentiation. In order to exclude fusion between MAB and CM as a mechanism, we used paraformaldehyde-fixed CM as scaffold. In this assay, human TnT also was detected, indicating that differentiation is sufficient to induce cardiac marker gene expression. Next, we tested the effect of MAB to improve cardiac function. MAB were injected intramuscularly in nude mice after myocardial infarction. Functional analysis using Millar catheter 2 weeks after infarction demonstrated that cell therapy lowered filling pressure and preserved diastolic function when compared to the PBS injected group (LVEDP: −20.3%, tau: −20.6%, vs PBS injected heart). Furthermore, left ventricular volume was also decreased (LVEDV/weight −27.3%). In summary, children-derived MAB express cardiac-specific genes after co-culture with CM and improved cardiac function in vivo. Given that MAB can be easily isolated and expanded from peripheral blood, these cells might be suitable to augment cardiac repair in children with heart failure.

scholarly journals Retinoic acid signaling is directly activated in cardiomyocytes and protects mouse hearts from apoptosis after myocardial infarction

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Fabio Da Silva ◽  
Fariba Jian Motamedi ◽  
Lahiru Chamara Weerasinghe Arachchige ◽  
Amelie Tison ◽  
Stephen T Bradford ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Retinoic Acid ◽  
Cardiac Development ◽  
Protective Role ◽  
Lineage Tracing ◽  
Late Gestation ◽  
Sequencing Analysis ◽  
Cell Type ◽  
Multiple Organs ◽  
Genes Encoding

Retinoic acid (RA) is an essential signaling molecule for cardiac development and plays a protective role in the heart after myocardial infarction (MI). In both cases, the effect of RA signaling on cardiomyocytes, the principle cell type of the heart, has been reported to be indirect. Here we have developed an inducible murine transgenic RA-reporter line using CreERT2 technology that permits lineage tracing of RA-responsive cells and faithfully recapitulates endogenous RA activity in multiple organs during embryonic development. Strikingly, we have observed a direct RA response in cardiomyocytes during mid-late gestation and after MI. Ablation of RA signaling through deletion of the Aldh1a1/a2/a3 genes encoding RA-synthesizing enzymes leads to increased cardiomyocyte apoptosis in adults subjected to MI. RNA sequencing analysis reveals Tgm2 and Ace1, two genes with well-established links to cardiac repair, as potential targets of RA signaling in primary cardiomyocytes, thereby providing novel links between the RA pathway and heart disease.

scholarly journals RBM20 Regulates CaV1.2 Surface Expression by Promoting Exon 9* Inclusion of CACNA1C in Neonatal Rat Cardiomyocytes

2019 ◽  
Vol 20 (22) ◽  
pp. 5591 ◽  
Author(s):  
Morinaga ◽  
Ito ◽  
Niimi ◽  
Maturana
Keyword(s):  
Alternative Splicing ◽  
Heart Development ◽  
Rna Binding ◽  
Surface Expression ◽  
Neonatal Rat ◽  
Sequencing Analysis ◽  
Rat Cardiomyocytes ◽  
Neonatal Rat Cardiomyocytes ◽  
Exon 9 ◽  
Sirna Knockdown

The CACNA1C gene encodes for the CaV1.2 protein, which is the pore subunit of cardiac l-type voltage-gated calcium (Ca2+) channels (l-channels). Through alternative splicing, CACNA1C encodes for various CaV1.2 isoforms with different electrophysiological properties. Splice variants of CaV1.2 are differentially expressed during heart development or pathologies. The molecular mechanisms of CACNA1C alternative splicing still remain incompletely understood. RNA sequencing analysis has suggested that CACNA1C is a potential target of the splicing factor RNA-binding protein motif 20 (RBM20). Here, we aimed at elucidating the role of RBM20 in the regulation of CACNA1C alternative splicing. We found that in neonatal rat cardiomyocytes (NRCMs), RBM20 overexpression promoted the inclusion of CACNA1C’s exon 9*, whereas the skipping of exon 9* occurred upon RBM20 siRNA knockdown. The splicing of other known alternative exons was not altered by RBM20. RNA immunoprecipitation suggested that RBM20 binds to introns flanking exon 9*. Functionally, in NRCMs, RBM20 overexpression decreased l-type Ca2+ currents, whereas RBM20 siRNA knockdown increased l-type Ca2+ currents. Finally, we found that RBM20 overexpression reduced CaV1.2 membrane surface expression in NRCMs. Taken together, our results suggest that RBM20 specifically regulates the inclusion of exon 9* in CACNA1C mRNA, resulting in reduced cell-surface membrane expression of l-channels in cardiomyocytes.

Abstract 49: Prolyl Isomerase Pin1 Regulates Cardiac Hypertrophy via Controlling Phosphorylation of Akt and MEK

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Haruhiro Toko ◽  
Mathias Konstandin ◽  
Natalie Gude ◽  
Mark Sussman
Keyword(s):  
Cardiac Hypertrophy ◽  
Protein Expression ◽  
High Serum ◽  
Neonatal Rat ◽  
Border Zone ◽  
Prolyl Isomerase ◽  
Rat Cardiomyocytes ◽  
Growth And Survival ◽  
Pin1 Protein

Rationale: Kinases and phosphatases regulate crucial aspects of growth and survival through phosphorylation and dephosphorylation of target substrates. Processes of cardiac hypertrophy, myocardial infarction, and heart failure are dictated in part by which kinases or phosphatases are involved and also by the intensity and duration of specific enzymatic activities. While research has identified numerous critical regulatory kinases and phosphatases in the myocardium, the intracellular mechanism for temporal regulation of signaling duration and intensity remains obscure. In the non-myocyte context, control of folding, activity, stability, and subcellular localization of proteins responsible for growth and survival is mediated by the prolyl isomerase Pin1. Objective: To establish the role of Pin1 in the heart. Method and Results: Initial characterization of myocardial Pin1 involved assessment of expression and localization during postnatal development or pathological challenge. Pin1 protein level was decreased and the location of Pin1 was changed from nucleus to cytoplasm with increasing age. Next, Pin1 protein expression and localization were assessed in the pathological challenged heart. Pin1 protein expression increases with pressure overload and ischemia, particularly in perivascular areas and in border zone myocytes, respectively. To determine the role of Pin1 on cardiac hypertrophy, siRNA to Pin1 (siPin1) was applied to neonatal rat cardiomyocytes. Western blot analysis showed that siPin1 decreased phosphorylation of Akt, and immunohistochemical analysis showed that siPin1 reduced cardiomyocyte size in response to high serum. siPin1 also decreased phosphorylation of MEK and reduced cardiomyocyte size in response to phenylephrine treatment. Furthermore, cardiac hypertrophy induced by transaortic constriction was ameliorated in Pin1 knockout mice, compared with littermate wild type mice. Conclusion: Expression and location of Pin1 during development and in response to pathologic challenge point to an important role for Pin1 in adaptation to myocardial growth or stress. Collective evidence indicates that Pin1 controls cardiac hypertrophy at least in part via regulating phosphorylation of Akt and MEK.

Abstract 15925: Newt Exosomes are Bioactive on Mammalian Heart, Enhancing Proliferation of Rat Cardiomyocytes and Improving Recovery After Myocardial Infarction

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Eleni Tseliou ◽  
Liu Weixin ◽  
Jackelyn Valle ◽  
Baiming Sun ◽  
Maria Mirotsou ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Critical Role ◽  
Dermal Fibroblasts ◽  
Neonatal Rat ◽  
Cardiomyocyte Proliferation ◽  
Rat Cardiomyocytes ◽  
Mesodermal Cell ◽  
Wistar Kyoto

Introduction: Adult newts can regenerate amputated cardiac tissue (and whole limbs) without fibrosis, unlike adult mammals which lack such regenerative capacity. Exosomes are nanoparticles which mediate intercellular communication and play a critical role in therapeutic regeneration. Hypothesis: We isolated exosomes from a newt mesodermal cell line, and evaluated their bioactivity in rat models. Methods: A1 cells, derived from the amputated limb buds of Notopthalmus viridescense (Brockes JP, 1988), were expanded in culture. Exosomes were isolated by polyethylene glycol precipitation of A1-conditioned serum-free media (or media conditioned by human dermal fibroblasts [DF] as a control) followed by centrifugation. Bioactivity was tested in vitro on neonatal rat ventricular myocytes (NRVM), and in vivo on acute myocardial infarction in Wistar-Kyoto rats (250μg or 500μg of A1-exosomes or vehicle [placebo] injected intramyocardially). Functional and histological analyses were performed 3 weeks after therapy. Results: A1-conditioned media yielded ~2.8±1Billion particles/ml of 129±1.1 nm diameter. In vitro, A1-exosomes increased the proliferative capacity of NRVM compared to DF-exosomes (4.98±0.89% vs 0.77±0.33%, p=0.035). Priming of DFs with A1-exosomes increased SDF-1 secretion compared to DF-exosomes (755±117pg/ml vs.368±21pg/ml, p=0.03). In vivo, both A1-exosome doses increased cardiac function compared to placebo (EF= 46±1% in 250μg, 49±4% in 500μg vs 36±1% in placebo, p=0.045 by ANOVA). Scar size was markedly decreased (11±1% in 250μg, 9±2% in 500μg vs 18±2% in placebo, p=0.006 by ANOVA), and infarct wall thickness was increased after A1-exosome treatment (1.7±0.11mm in 250μg, 1.85±0.16mm in 500μg vs 1.17±0.11mm in Placebo, p=0.01 by ANOVA). Donor-specific antibodies were present at barely detectable levels in the serum of animals that had been injected with A1-exosomes. Conclusions: Newt exosomes stimulate rat cardiomyocyte proliferation and improve functional and structural outcomes in rats with myocardial infarction. Characterization of the RNA and protein content of newt exosomes, now in progress, may provide clues regarding conserved (or newt-unique) molecular mediators of therapeutic benefit.

scholarly journals PKCα regulates the hypertrophic growth of cardiomyocytes through extracellular signal–regulated kinase1/2 (ERK1/2)

2002 ◽  
Vol 156 (5) ◽  
pp. 905-919 ◽  
Author(s):  
Julian C. Braz ◽  
Orlando F. Bueno ◽  
Leon J. De Windt ◽  
Jeffery D. Molkentin
Keyword(s):  
Marker Gene ◽  
Dominant Negative ◽  
Neonatal Rat ◽  
Cardiomyocyte Hypertrophy ◽  
Leucine Incorporation ◽  
Wild Type ◽  
Rat Cardiomyocytes ◽  
Signal Transducers ◽  
Hypertrophic Growth ◽  
Extracellular Signal

Members of the protein kinase C (PKC) isozyme family are important signal transducers in virtually every mammalian cell type. Within the heart, PKC isozymes are thought to participate in a signaling network that programs developmental and pathological cardiomyocyte hypertrophic growth. To investigate the function of PKC signaling in regulating cardiomyocyte growth, adenoviral-mediated gene transfer of wild-type and dominant negative mutants of PKCα, βII, δ, and ε (only wild-type ζ) was performed in cultured neonatal rat cardiomyocytes. Overexpression of wild-type PKCα, βII, δ, and ε revealed distinct subcellular localizations upon activation suggesting unique functions of each isozyme in cardiomyocytes. Indeed, overexpression of wild-type PKCα, but not βII, δ, ε, or ζ induced hypertrophic growth of cardiomyocytes characterized by increased cell surface area, increased [3H]-leucine incorporation, and increased expression of the hypertrophic marker gene atrial natriuretic factor. In contrast, expression of dominant negative PKCα, βII, δ, and ε revealed a necessary role for PKCα as a mediator of agonist-induced cardiomyocyte hypertrophy, whereas dominant negative PKCε reduced cellular viability. A mechanism whereby PKCα might regulate hypertrophy was suggested by the observations that wild-type PKCα induced extracellular signal–regulated kinase1/2 (ERK1/2), that dominant negative PKCα inhibited PMA-induced ERK1/2 activation, and that dominant negative MEK1 (up-stream of ERK1/2) inhibited wild-type PKCα–induced hypertrophic growth. These results implicate PKCα as a necessary mediator of cardiomyocyte hypertrophic growth, in part, through a ERK1/2-dependent signaling pathway.

scholarly journals Initiation and propagation of ectopic waves: insights from an in vitro model of ischemia-reperfusion injury

2002 ◽  
Vol 283 (2) ◽  
pp. H741-H749 ◽  
Author(s):  
Ara Arutunyan ◽  
Luther M. Swift ◽  
Narine Sarvazyan
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Neonatal Rat ◽  
Border Zone ◽  
Ectopic Activity ◽  
Functional Layer ◽  
Rat Cardiomyocytes ◽  
Coupled Cells ◽  
Vitro Model

The objective of the present study was to directly visualize ectopic activity associated with ischemia-reperfusion and its progression to arrhythmia. To accomplish this goal, we employed a two-dimensional network of neonatal rat cardiomyocytes and a recently developed model of localized ischemia-reperfusion. Washout of the ischemia-like solution resulted in tachyarrhythmic episodes lasting 15–200 s. These episodes were preceded by the appearance of multiple ectopic sources and propagation of ectopic activity along the border of the former ischemic zone. The ectopic sources exhibited a slow rise in diastolic calcium, which disappeared upon return to the original pacing pattern. Border zone propagation of ectopic activity was followed by its escape into the surrounding control network, generating arrhythmias. Together, these observations suggest that upon reperfusion, a distinct layer, which consists of ectopically active, poorly coupled cells, is formed transiently over an injured area. Despite being neighbored by a conductive and excitable tissue, this transient functional layer is capable of sustaining autonomous waves and serving as a special conductive medium through which ectopic activity can propagate before spreading into the surrounding healthy tissue.

Significance of ERK cascade compared with JAK/STAT and PI3-K pathway in gp130-mediated cardiac hypertrophy

2000 ◽  
Vol 279 (4) ◽  
pp. H1635-H1644 ◽  
Author(s):  
Hiroaki Kodama ◽  
Keiichi Fukuda ◽  
Jing Pan ◽  
Motoaki Sano ◽  
Toshiyuki Takahashi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Atrial Natriuretic Peptide ◽  
Cardiac Hypertrophy ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Janus Kinase ◽  
Neonatal Rat ◽  
Rat Cardiomyocytes ◽  
Extracellular Signal ◽  
Atrial Natriuretic

We compared the role of the Raf-1/mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MEK)/extracellular signal-regulated protein kinase (ERK)/p90RSK cascade in gp130-mediated cardiac hypertrophy with the contribution of the Janus kinase (JAK)/signal transduction and activation of transcription (STAT) and phosphatidylinositide 3-kinase (PI3-K) pathways. Primary cultured neonatal rat cardiomyocytes were stimulated with leukemia inhibitory factor (LIF). LIF sequentially activated Raf-1, MEK1/2, ERK1/2, and p90RSK. We used PD-98059 (a specific MEK inhibitor), AG-490 (a JAK2 inhibitor), and wortmannin (a PI3-K inhibitor) to confirm that this cascade was independent of the JAK/STAT and PI3-K/p70 S6 kinase (S6K) pathways. PD-98059, AG-490, and wortmannin suppressed the LIF-induced increase in [3H]phenylalanine uptake by 54.7, 21.5, and 25.6%, respectively, and inhibited the increase in cell area by 61.2, 42.8, and 39.2%, respectively. Reorganization of myofilaments was predominantly suppressed by AG-490. LIF-induced expression of c- fos, brain natriuretic peptide, and skeletal α-actin mRNA was markedly suppressed by PD-98059 and moderately suppressed by wortmannin and AG-490. Atrial natriuretic peptide was significantly suppressed by AG-490. These findings indicate that this pathway is critically involved in protein synthesis, induction of c- fos, brain natriuretic peptide, and skeletal α-actin expression and is partially involved in myofilament reorganization and atrial natriuretic peptide induction in gp130-mediated cardiac hypertrophy.

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