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Reciprocal Interaction Between IK1 and If in Biological Pacemakers: A Simulation Study

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Specialty Biology
Date 2021 Mar 10
PMID 33690622
Citations 1
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Abstract

Pacemaking dysfunction (PD) may result in heart rhythm disorders, syncope or even death. Current treatment of PD using implanted electronic pacemakers has some limitations, such as finite battery life and the risk of repeated surgery. As such, the biological pacemaker has been proposed as a potential alternative to the electronic pacemaker for PD treatment. Experimentally and computationally, it has been shown that bio-engineered pacemaker cells can be generated from non-rhythmic ventricular myocytes (VMs) by knocking out genes related to the inward rectifier potassium channel current (IK1) or by overexpressing hyperpolarization-activated cyclic nucleotide gated channel genes responsible for the "funny" current (If). However, it is unclear if a bio-engineered pacemaker based on the modification of IK1- and If-related channels simultaneously would enhance the ability and stability of bio-engineered pacemaking action potentials. In this study, the possible mechanism(s) responsible for VMs to generate spontaneous pacemaking activity by regulating IK1 and If density were investigated by a computational approach. Our results showed that there was a reciprocal interaction between IK1 and If in ventricular pacemaker model. The effect of IK1 depression on generating ventricular pacemaker was mono-phasic while that of If augmentation was bi-phasic. A moderate increase of If promoted pacemaking activity but excessive increase of If resulted in a slowdown in the pacemaking rate and even an unstable pacemaking state. The dedicated interplay between IK1 and If in generating stable pacemaking and dysrhythmias was evaluated. Finally, a theoretical analysis in the IK1/If parameter space for generating pacemaking action potentials in different states was provided. In conclusion, to the best of our knowledge, this study provides a wide theoretical insight into understandings for generating stable and robust pacemaker cells from non-pacemaking VMs by the interplay of IK1 and If, which may be helpful in designing engineered biological pacemakers for application purposes.

Citing Articles

Understanding PITX2-Dependent Atrial Fibrillation Mechanisms through Computational Models.

Bai J, Lu Y, Zhu Y, Wang H, Yin D, Zhang H Int J Mol Sci. 2021; 22(14).

PMID: 34299303 PMC: 8307824. DOI: 10.3390/ijms22147681.

References
1.
Wilders R, Verheijck E, Kumar R, Goolsby W, van Ginneken A, Joyner R . Model clamp and its application to synchronization of rabbit sinoatrial node cells. Am J Physiol. 1996; 271(5 Pt 2):H2168-82. DOI: 10.1152/ajpheart.1996.271.5.H2168. View

2.
Kapoor N, Liang W, Marban E, Cho H . Direct conversion of quiescent cardiomyocytes to pacemaker cells by expression of Tbx18. Nat Biotechnol. 2012; 31(1):54-62. PMC: 3775583. DOI: 10.1038/nbt.2465. View

3.
Ono K, Iijima T . Pathophysiological significance of T-type Ca2+ channels: properties and functional roles of T-type Ca2+ channels in cardiac pacemaking. J Pharmacol Sci. 2005; 99(3):197-204. DOI: 10.1254/jphs.fmj05002x2. View

4.
Mesirca P, Torrente A, Mangoni M . T-type channels in the sino-atrial and atrioventricular pacemaker mechanism. Pflugers Arch. 2014; 466(4):791-9. DOI: 10.1007/s00424-014-1482-6. View

5.
Kurata Y, Matsuda H, Hisatome I, Shibamoto T . Roles of hyperpolarization-activated current If in sinoatrial node pacemaking: insights from bifurcation analysis of mathematical models. Am J Physiol Heart Circ Physiol. 2010; 298(6):H1748-60. DOI: 10.1152/ajpheart.00729.2009. View