Chimeric G-CSF Receptor-Mediated STAT3 Activation Contributes to Efficient induction of Cardiomyocytes from Mouse Induced Pluripotent Stem Cells.

Abstract

Producing a sufficient number of induced cardiomyocytes from pluripotent stem cells has been of great demand for regeneration therapy of severe heart failure. However, it is still challenging to efficiently differentiate cardiomyocytes with low costs. Reportedly, granulocyte colony-stimulating factor (G-CSF) receptor (GCSFR) signaling activates signal transducers and activators of transcription (STAT) signaling and enhances cardiac differentiation from pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells (iPSCs). To economically and efficiently produce cardiomyocytes from iPSCs through GCSFR/STAT axis activation, we constructed antibody/receptor chimeras that can respond to an inexpensive small molecule. Single-chain Fv of anti-fluorescein (FL) antibody was ligated to transmembrane/cytoplasmic domains of GCSFRs, enabling transduction of GCSFR signaling in response to FL-conjugated bovine serum albumin (BSA-FL) as an inexpensive alternative ligand. Mouse iPSC lines constitutively expressing these chimeric receptors were established, and they exhibited increased BSA-FL-induced STAT3 phosphorylation in a dose-dependent manner. This response was abolished by an inhibitor of Janus tyrosine kinase (JAK). In addition, BSA-FL stimulation also increased the incidence of beating embryoid body formation and upregulated cardiac-specific gene expressions at mRNA and protein levels after differentiation in these iPSC lines. Therefore, the chimeric GCSFRs activated endogenous GCSFR signaling at least via the JAK/STAT3 pathway, thereby enhancing cardiac differentiation from iPSCs. This approach using the chimeric receptor, as an economical and powerful strategy, could contribute to stem cell-based cardiac regeneration therapy. This article is protected by copyright. All rights reserved.