Molecular barriers to direct cardiac reprogramming

Abstract

Myocardial infarction afflicts close to three quarters of a million Americans annually, resulting in reduced heart function, arrhythmia, and frequently death. Cardiomyocyte death reduces the heart’s pump capacity while the deposition of a non-conductive scar incurs the risk of arrhythmia. Direct cardiac reprogramming emerged as a novel technology to simultaneously reduce scar tissue and generate new cardiomyocytes to restore cardiac function. This technology converts endogenous cardiac fibroblasts directly into induced cardiomyocyte-like cells using a variety of cocktails including transcription factors, microRNAs, and small molecules. Although promising, direct cardiac reprogramming is still in its fledging phase, and numerous barriers have to be overcome prior to its clinical application. This review discusses current findings to optimize reprogramming efficiency, including reprogramming factor cocktails and stoichiometry, epigenetic barriers to cell fate reprogramming, incomplete conversion and residual fibroblast identity, requisite growth factors, and environmental cues. Finally, we address the current challenges and future directions for the field.

Keywords

cardiac reprogramming / myocardial infarction / epigenetics / heart regeneration

References

[1] AbadM (2017) Notch inhibition enhances cardiac reprogramming by increasing MEF2C transcriptional activity.Stem Cell Rep. doi:10.1016/j.stemcr.2017.01.025

[2] AddisRC (2013) Optimization of direct fibroblast reprogramming to cardiomyocytes using calcium activity as a functional measure of success.J Mol Cell Cardiol60:97–106

[3] ChenHP (2011) HDAC inhibition promotes cardiogenesis and the survival of embryonic stem cells through proteasome-dependent pathway.J Cell Biochem112:3246–3255

[4] ChopraA (2012) Reprogramming cardiomyocyte mechanosensing by crosstalk between integrins and hyaluronic acid receptors.J Biomech45:824–831

[5] ChristoforouN (2013) Transcription factors MYOCD, SRF, Mesp1 and SMARCD3 enhance the cardio-inducing effect of GATA4, TBX5, and MEF2C during direct cellular reprogramming.PloS One8:e63577

[6] Dal-PraS, HodgkinsonCP, MirotsouM, KirsteI, DzauVJ (2017) Demethylation of H3K27 is essential for the induction of direct cardiac reprogramming by miR combo.Circ Res. doi:10.1161/CIRCRESAHA.116.308741

[7] FuY (2015) Direct reprogramming of mouse fibroblasts into cardiomyocytes with chemical cocktails.Cell Res25:1013–1024

[8] Heart Attack Facts & Statistics|cdc.gov (2016) Accessed 7 Nov 2016

[9] Heart Disease Fact Sheet|Data & Statistics|DHDSP|CDC (2016) Accessed 7 Nov 2016

[10] HiraiH, KikyoN (2014) Inhibitors of suppressive histone modification promote direct reprogramming of fibroblasts to cardiomyocytelike cells.Cardiovasc Res102:188–190

[11] IedaM (2010) Direct reprogramming of fibroblasts into functional cardiomyocytes by defined factors.Cell142:375–386

[12] IfkovitsJL, AddisRC, EpsteinJA, GearhartJD (2014) Inhibition of TGFβ signaling increases direct conversion of fibroblasts to induced cardiomyocytes.PloS One9:e89678

[13] InagawaK (2012) Induction of cardiomyocyte-like cells in infarct hearts by gene transfer of Gata4, Mef2c, and Tbx5.Circ Res111:1147–1156

[14] JayawardenaTM (2012) MicroRNA-mediated in vitro and in vivo direct reprogramming of cardiac fibroblasts to cardiomyocytes.Circ Res110:1465–1473

[15] JayawardenaTM (2015) MicroRNA induced cardiac reprogramming in vivo: evidence for mature cardiac myocytes and improved cardiac function.Circ Res116:418–424

[16] KaramboulasC (2006) HDAC activity regulates entry of mesoderm cells into the cardiac muscle lineage.J Cell Sci119:4305–4314

[17] KongYP, CarrionB, SinghRK, PutnamAJ (2013) Matrix identity and tractional forces influence indirect cardiac reprogramming.Sci Rep3:3474

[18] LiY (2016) Tissue-engineered 3-dimensional (3D) microenvironment enhances the direct reprogramming of fibroblasts into cardiomyocytes by microRNAs.Sci Rep6:38815

[19] LinZ, PuWT (2014) Strategies for cardiac regeneration and repair.Sci Transl Med6(239):239rv1

[20] LiuZ (2016a) Re-patterning of H3K27me3, H3K4me3 and DNA methylation during fibroblast conversion into induced cardiomyocytes.Stem Cell Res16:507–518

[21] LiuL (2016b) Targeting Mll1 H3K4 methyltransferase activity to guide cardiac lineage specific reprogramming of fibroblasts.Cell Discov2:16036

[22] MaH, WangL, YinC, LiuJ, QianL (2015) In vivo cardiac reprogramming using an optimal single polycistronic construct.Cardiovasc Res108:217–219

[23] MathisonM (2012) In vivo cardiac cellular reprogramming efficacy is enhanced by angiogenic preconditioning of the infarcted myocardium with vascular endothelial growth factor.J Am Heart Assoc1:e005652

[24] MathisonM (2014) ‘Triplet’ polycistronic vectors encoding Gata4, Mef2c, and Tbx5 enhances postinfarct ventricular functional improvement compared with singlet vectors.J Thorac Cardiovasc Surg148(1656):1664.e2

[25] McKinseyTA, OlsonEN (2004) Cardiac histone acetylation–therapeutic opportunities abound.Trends Genet TIG20:206–213

[26] MiskaEA (1999) HDAC4 deacetylase associates with and represses the MEF2 transcription factor.EMBO J18:5099–5107

[27] MohamedTMA (2016) Chemical enhancement of in vitro and in vivo direct cardiac reprogramming.Circulation. doi:10.1161/CIRCULATIONAHA.116.024692

[28] MorezC (2015) Enhanced efficiency of genetic programming toward cardiomyocyte creation through topographical cues.Biomaterials70:94–104

[29] MuraokaN (2014) MiR-133 promotes cardiac reprogramming by directly repressing Snai1 and silencing fibroblast signatures.EMBO J33:1565–1581

[30] ProtzeS (2012) A new approach to transcription factor screening for reprogramming of fibroblasts to cardiomyocyte-like cells.J Mol Cell Cardiol53:323–332

[31] QianL (2012) In vivo reprogramming of murine cardiac fibroblasts into induced cardiomyocytes.Nature485:593–598

[32] SiaJ, YuP, SrivastavaD, LiS (2016) Effect of biophysical cues on reprogramming to cardiomyocytes.Biomaterials103:1–11

[33] SongK (2012) Heart repair by reprogramming non-myocytes with cardiac transcription factors.Nature485:599–604

[34] TakeuchiJK, BruneauBG (2009) Directed transdifferentiation of mouse mesoderm to heart tissue by defined factors.Nature459:708–711

[35] VaseghiHR (2016) Generation of an inducible fibroblast cell line for studying direct cardiac reprogramming.Genesis2000 (54):398–406

[36] WangH (2014) Small molecules enable cardiac reprogramming of mouse fibroblasts with a single factor, Oct4.Cell Rep6:951–960

[37] WangL (2015a) Stoichiometry of Gata4, Mef2c, and Tbx5 influences the efficiency and quality of induced cardiac myocyte reprogramming.Circ Res116:237–244

[38] WangL (2015b) Improved generation of induced cardiomyocytes using a polycistronic construct expressing optimal ratio of Gata4, Mef2c and Tbx5.J Vis Exp JoVE. doi:10.3791/53426

[39] YamakawaH (2015) Fibroblast growth factors and vascular endothelial growth factor promote cardiac reprogramming under defined conditions.Stem Cell Rep5:1128–1142

[40] ZhaoY (2015) High-efficiency reprogramming of fibroblasts into cardiomyocytes requires suppression of pro-fibrotic signalling.Nat Commun6:8243

[41] ZhouH, DicksonME, KimMS, Bassel-DubyR, OlsonEN (2015) Akt1/protein kinase B enhances transcriptional reprogramming of fibroblasts to functional cardiomyocytes.Proc Natl Acad Sci USA112:11864–11869

[42] ZhouY (2016) Bmi1 is a key epigenetic barrier to direct cardiac reprogramming.Cell Stem Cell18:382–395

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The Author(s) 2017. This article is an open access publication