# Electrophysiological characterization of human pluripotent stem cell derived cardiomyocytes and their application as biological pacemakers

> **NIH NIH F31** · EMORY UNIVERSITY · 2020 · $45,520

## Abstract

ABSTRACT
Background: From the first successful differentiation of human stem cells to cardiomyocytes, stem cells have
held promise in the field of cardiac regeneration. These cells provide an indefinite source of de novo
cardiomyocytes and potentially unlimited tissue for human transplantation. Yet the mammalian heart is a complex
organ, comprised of four chambers, a highly coordinated electrical conduction system, and a heterogeneous mix
of cell types, which may not match the differentiated tissues produced in vitro. Despite efforts focused on
increasing cardiomyocyte differentiation yield, relatively little progress has been made in differentiating function-
specific cardiomyocytes, such as pacemaker cells. Differentiation of nodal pacemaker cells would provide a new
cell source for biological pacing of the heart. Recently, retinoic acid (Ra) signaling has been shown to play a
critical role in the differentiation of atrial and pacemaker cells, mimicking the cells found in the native pacemaker.
I hypothesize that specific differentiation of pacemaker cells with Ra would provide superior biological
pacemaking function both in vitro and in vivo, compared to conventional, heterogeneous stem cell-derived
populations. The proposed work seeks to fully characterize the genetic profile, functional electrophysiological
properties, and biological pacemaker potential, both in vitro and in vivo, of Ra-derived cardiomyocytes.
Approach: To derive pacemakers, human induced pluripotent stem cells (hiPSC) will be differentiated as
monolayers over a 14-day protocol with and without Ra. Our preliminary data indicates that Ra treatment
enriches molecular and genetic expression profiles to that of native pacemaker cells. Aim 1 of this work seeks
apply our Ra differentiation protocol on 6 different hiPSC lines (half male / half female) derived from umbilical
cord blood. Thus, allowing us to examine the applicability of this method for pediatric patients. In Aim 2, hiPSC-
derived cells will be aggregated into spheroids, pacing units. The size of these pacing units will be optimized for
maximum spontaneous beating with minimal cell death. Pacemaker function of these spheres will be tested with
our in vitro engraftment model. In Aim 3, optimized pacing units will be engrafted to rat ventricular myocardium
in vivo to record spontaneous beating induced by the hiPSC-pacing units. The major readouts are i) RT-qPCR
analysis of gene expression, ii) single-cell intracellular potential recordings from patch-clamp, iii) macro-scale,
multi-electrode array measurements of field potentials, iv) high-resolution optical mapping of monolayers and ex
vivo whole hearts with a voltage-sensitive dye, v) 24/7 telemetry biopotential recordings of ECG in vivo, and vi)
echocardiographic measurements. Successful completion of this project will lead to the first in-depth study of the
biological pacemaker potential of Ra-derived cardiomyocytes, in terms of optimized differentiation, dynamic dose...

## Key facts

- **NIH application ID:** 9992375
- **Project number:** 1F31HL149272-01A1
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** David Wolfson
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $45,520
- **Award type:** 1
- **Project period:** 2020-05-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9992375

## Citation

> US National Institutes of Health, RePORTER application 9992375, Electrophysiological characterization of human pluripotent stem cell derived cardiomyocytes and their application as biological pacemakers (1F31HL149272-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9992375. Licensed CC0.

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