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Susceptibility of murine induced pluripotent stem cell-derived cardiomyocytes to hypoxia and nutrient deprivation

Authors

  • A. Brodarac
  • T. Šarić
  • B. Oberwallner
  • S. Mahmoodzadeh
  • K. Neef
  • J. Albrecht
  • K. Burkert
  • M. Oliverio
  • F. Nguemo
  • Y.H. Choi
  • W.F. Neiss
  • I. Morano
  • J. Hescheler
  • C. Stamm

Journal

  • Stem Cell Research & Therapy

Citation

  • Stem Cell Res Ther 6 (1): 83

Abstract

  • INTRODUCTION: Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) may be suitable for myocardial repair. While their functional and structural properties have been extensively investigated, their response to ischemia-like conditions has not yet been clearly defined. METHODS: iPS-CMs were differentiated and enriched from murine iPS cells expressing eGFP and puromycin resistance genes under the control of an alpha-MHC promoter. iPS-CMs maturity and function were characterized by microscopy, rt-PCR, calcium transient recordings, electrophysiology, and mitochondrial function assays, and compared to those from neonatal murine cardiomyocytes (N-CMs). iPS-CMs as well as N-CMs were exposed for 3 h to hypoxia (1% O2) and glucose/serum deprivation (GSD), and viability, apoptosis markers, reactive oxygen species (ROS), mitochondrial membrane potential (Deltapsim) and intracellular stress signaling cascades were investigated. Then, the iPS-CMs response to mesenchymal stromal cell-conditioned medium (MSC-CoM) was determined. RESULTS: iPS-CMs displayed key morphological and functional properties that were comparable to those of N-CMs, but several parameters indicated an earlier iPS-CMs maturation stage. During hypoxia/GSD, iPS-CMs exhibited a significantly higher proportion of poly-caspase-active, 7-AAD- and TUNEL-positive cells than N-CMs. The average mitochondrial membrane potential (Deltapsim) was reduced in "ischemic" iPS-CMs but remained unchanged in N-CMs, ROS production was only increased in "ischemic" iPS-CMs, and oxidoreductase activity in iPS-CMs dropped more rapidly than in N-CMs. In iPS-CMs, hypoxia/GSD led to upregulation of Hsp70 transcripts and decreased STAT3 phosphorylation and total PKCepsilon protein expression. Treatment with MSC-CoM preserved oxidoreductase activity and restored pSTAT3 and PKCepsilon levels. CONCLUSION: iPS-CMs appear to be particularly sensitive to hypoxia and nutrient deprivation. Counteracting the ischemic susceptibility of iPS-CMs with MSC-conditioned medium may help enhance their survival and efficacy in cell-based approaches for myocardial repair.


DOI

doi:10.1186/s13287-015-0057-6