Aberrant α-Adrenergic Hypertrophic Response in Cardiomyocytes from Human Induced Pluripotent Cells

Abstract

SummaryCardiomyocytes from human embryonic stem cells (hESC-CMs) and induced pluripotent stem cells (hiPSC-CMs) represent new models for drug discovery. Although hypertrophy is a high-priority target, we found that hiPSC-CMs were systematically unresponsive to hypertrophic signals such as the α-adrenoceptor (αAR) agonist phenylephrine (PE) compared to hESC-CMs. We investigated signaling at multiple levels to understand the underlying mechanism of this differential responsiveness. The expression of the normal α1AR gene, ADRA1A, was reversibly silenced during differentiation, accompanied by ADRA1B upregulation in either cell type. ADRA1B signaling was intact in hESC-CMs, but not in hiPSC-CMs. We observed an increased tonic activity of inhibitory kinase pathways in hiPSC-CMs, and inhibition of antihypertrophic kinases revealed hypertrophic increases. There is tonic suppression of cell growth in hiPSC-CMs, but not hESC-CMs, limiting their use in investigation of hypertrophic signaling. These data raise questions regarding the hiPSC-CM as a valid model for certain aspects of cardiac disease.

Discovery of novel small molecule inhibitors of cardiac hypertrophy using high throughput, high content imaging

“…Adaptation of this hypertrophy assay to 384-well plates will facilitate expanded screening efforts. Furthermore, this approach could be employed with iPS-derived cardiac myocytes [21], although optimized culture methods will likely be needed to maximize the responses of these cells to hypertrophic agonists [22]. …”

Cardiomyocytes from human pluripotent stem cells: From laboratory curiosity to industrial biomedical platform

“…As examples, chemical induction of hypertrophy in hPSC-CMs by angiotensin II, phenylephrine, or endothelin-1 has been evaluated in 96-well or 384-well plates. The Cellomics Arrayscan was used to show that some aspects of the pathways underlying hypertrophy are defective in multiple lines of hiPSC-CMs relative to hESC-CMs [74], while the ImageXpress Micro platform was used to calculate the EC50 of enthothelin-1 as 11 pM in commercial hiPSC-CMs [161]. Imaging was also used to examine hypertrophic responses of patient-specific hiPSC-CMs from a ten-member family cohort carrying a hereditary hypertrophic cardiomyopathy missense mutation (Arg663His) in the MYH7 gene [63].…”

“…Thus, Foldes and colleagues [74] described robust hypertrophic responses to phenylephrine in hESC-CMs but not hiPSC-CMs. This was irrespective of the reprogramming or differentiation method used.…”

Maturation status of sarcomere structure and function in human iPSC-derived cardiac myocytes

“…Additionally, as shown above [89], iPSC-CMs can be useful for examining the mechanism of action of untested compounds. In this context, there is a report of altered hypertrophic signaling via the α- adrenergic pathway in hiPSC-CMs that should be addressed by detailed further study when pursuing iPSC lines for drug discovery [90]. …”