Neonatal Rat Cardiomyocytes Show Characteristics of Nonhomotypic Gap Junction Channels

Schulte, Jan S.; Scheffler, A.; Rojas-Gómez, Diana Marcela; Mohr, Friedrich W.; Dhein, Stefan

doi:10.1080/15419060802014404

Cited by 7 publications

(6 citation statements)

References 35 publications

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“…In addition, it was investigated whether the effects of Cx43 knockdown could be reversed by Cx45 overexpression. The reason to choose Cx45 for this purpose was that it can be engaged in the formation of functional homotypic as well as heterotypic gap junctions composed of homomeric or heteromeric connexins [24][25][26][27]. In this study, it was indeed established that after transduction with a Cx45-encoding LV, Cx43;(1) fetal AM hMSCs express high levels of Cx45 mRNA leading to rescue of their efficient gap junctional communication with nrCMCs.…”

Section: Gap Junctions and Hmscsmentioning

confidence: 78%

Gap Junctional Coupling with Cardiomyocytes is Necessary but Not Sufficient for Cardiomyogenic Differentiation of Cocultured Human Mesenchymal Stem Cells

et al. 2012

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Gap junctional coupling is important for functional integration of transplanted cells with host myocardium. However, the role of gap junctions in cardiomyogenic differentiation of transplanted cells has not been directly investigated. The objective of this work is to study the role of connexin43 (Cx43) in cardiomyogenic differentiation of human mesenchymal stem cells (hMSCs). Knockdown of Cx43 gene expression (Cx43↓) was established in naturally Cx43-rich fetal amniotic membrane (AM) hMSCs, while Cx43 was overexpressed (Cx43↑) in inherently Cx43-poor adult adipose tissue (AT) hMSCs. The hMSCs were exposed to cardiomyogenic stimuli by coincubation with neonatal rat ventricular cardiomyocytes (nrCMCs) for 10 days. Differentiation was assessed by immunostaining and whole-cell current clamping. To establish whether the effects of Cx43 knockdown could be rescued, Cx45 was overexpressed in Cx43↓ fetal AM hMSCs. Ten days after coincubation, not a single Cx43↓ fetal AM hMSC, control adult AT MSC, or Cx43↑ adult AT mesenchymal stem cell (MSC) expressed α-actinin, while control fetal AM hMSCs did (2.2% ± 0.4%, n = 5,000). Moreover, functional cardiomyogenic differentiation, based on action potential recordings, occurred only in control fetal AM hMSCs. Of interest, Cx45 overexpression in Cx43↓ fetal AM hMSCs restored their ability to undergo cardiomyogenesis (1.6% ± 0.4%, n = 2,500) in coculture with nrCMCs. Gap junctional coupling is required for differentiation of fetal AM hMSCs into functional CMCs after coincubation with nrCMCs. Heterocellular gap junctional coupling thus plays an important role in the transfer of cardiomyogenic signals from nrCMCs to fetal hMSCs but is not sufficient to induce cardiomyogenic differentiation in adult AT hMSCs. Disclosure of potential conflicts of interest is found at the end of this article.

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Section: Gap Junctions and Hmscsmentioning

confidence: 78%

Gap Junctional Coupling with Cardiomyocytes is Necessary but Not Sufficient for Cardiomyogenic Differentiation of Cocultured Human Mesenchymal Stem Cells

et al. 2012

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“…27 In addition, neonatal rat cardiomyocytes can coexpress more than one connexin or gap junction protein isoform which are able to form homometrichomotypic gap junction channels aside from potential homometric-heterotypic, heterometric-homotypic, and heterometri-heterotypic channels. 28 The gating behavior of the channels is affected by the length and type of the connexin present and, in effect, signal transmission between cells can be obstructed. And thus, asymmetric behavior observed in a group of cells is due to the voltage sensitivity difference between cardiomyocytes.…”

Section: Comparison Of Single Cardiomyocytes and Group Of Cardiomyocymentioning

confidence: 99%

Centrifugal microfluidic platform for single-cell level cardiomyocyte-based drug profiling and screening

et al. 2015

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Drug screening and profiling is an important phase in drug discovery, development, and marketing. However, some profiling tests are not routinely done because of the needed additional technical skills and costly maintenance, which leads to cases of unexpected side effects or adverse drug reactions (ADRs). This study presents the design and operation of a microfluidic chip for single-cell level drug screening and profiling as an alternative platform for this purpose. Centrifugation was utilized to trap isolated single and groups of primary cultured neonatal rat cardiomyocytes in the same chip. In the off-spin operation of the chip, the cells can be observed under a microscope and movies of the beat motion can be recorded. The beat profiles of the cells were generated by image correlation analysis of the recorded video to study the contractile characteristics (beating rate, beating strength, and inter-beat duration). By utilizing this non-invasive tool, long term continuous monitoring, right after trapping, was made possible and cell growth and dynamics were successfully observed in the chip. Media and liquid replacement does not require further centrifugation but instead utilizes capillary flow only. The effect of carbachol (100 μM) and isoproterenol (4 μg mL(-1)) on single cells and groups of cells was demonstrated and the feature for immunostaining (β-actin) applicability of the chip was revealed. Furthermore, these findings can be helpful for the headway of non-invasive profiling of cardiomyocytes and for future chip design and operation of high-throughput lab-on-a-chip devices.

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“…Moreover, heterotypic channels consisting of hemichannels of different connexin isoforms can show asymmetric voltage-dependent gating. Asymmetric gating refers to the observation that the conductance-to-voltage relationship depends on the polarity of the transjunctional voltage (see e.g., Bukauskas and Verselis, 2004; Schulte et al, 2008). …”

Section: How Are Cardiac Cells Coupled?mentioning

confidence: 99%

Remodeling of cardiac passive electrical properties and susceptibility to ventricular and atrial arrhythmias

et al. 2014

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Coordinated electrical activation of the heart is essential for the maintenance of a regular cardiac rhythm and effective contractions. Action potentials spread from one cell to the next via gap junction channels. Because of the elongated shape of cardiomyocytes, longitudinal resistivity is lower than transverse resistivity causing electrical anisotropy. Moreover, non-uniformity is created by clustering of gap junction channels at cell poles and by non-excitable structures such as collagenous strands, vessels or fibroblasts. Structural changes in cardiac disease often affect passive electrical properties by increasing non-uniformity and altering anisotropy. This disturbs normal electrical impulse propagation and is, consequently, a substrate for arrhythmia. However, to investigate how these structural changes lead to arrhythmias remains a challenge. One important mechanism, which may both cause and prevent arrhythmia, is the mismatch between current sources and sinks. Propagation of the electrical impulse requires a sufficient source of depolarizing current. In the case of a mismatch, the activated tissue (source) is not able to deliver enough depolarizing current to trigger an action potential in the non-activated tissue (sink). This eventually leads to conduction block. It has been suggested that in this situation a balanced geometrical distribution of gap junctions and reduced gap junction conductance may allow successful propagation. In contrast, source-sink mismatch can prevent spontaneous arrhythmogenic activity in a small number of cells from spreading over the ventricle, especially if gap junction conductance is enhanced. Beside gap junctions, cell geometry and non-cellular structures strongly modulate arrhythmogenic mechanisms. The present review elucidates these and other implications of passive electrical properties for cardiac rhythm and arrhythmogenesis.

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Neonatal Rat Cardiomyocytes Show Characteristics of Nonhomotypic Gap Junction Channels

Cited by 7 publications

References 35 publications

Gap Junctional Coupling with Cardiomyocytes is Necessary but Not Sufficient for Cardiomyogenic Differentiation of Cocultured Human Mesenchymal Stem Cells

Gap Junctional Coupling with Cardiomyocytes is Necessary but Not Sufficient for Cardiomyogenic Differentiation of Cocultured Human Mesenchymal Stem Cells

Centrifugal microfluidic platform for single-cell level cardiomyocyte-based drug profiling and screening

Remodeling of cardiac passive electrical properties and susceptibility to ventricular and atrial arrhythmias

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