1 Brade, T., Pane, L. S., Moretti, A., Chien, K. R. & Laugwitz, K.-L. Embryonic heart progenitors and cardiogenesis. Cold Spring Harb. Perspect. Med. 3, a013847 (2013).

2 Männer, J. & Ruiz-Lozano, P. Development and function of the epicardium. Adv. Dev. Biol. 18, 333–357 (2007).

3 Pérez-Pomares, J.-M. et al. Origin of coronary endothelial cells from epicardial mesothelium in avian embryos. Int. J. Dev. Biol. 46, 1005–1013 (2002).

4 Smart, N. et al. Thymosin β4 induces adult epicardial progenitor mobilization and neovascularization. Nature 445, 177–182 (2007).

5 Zhou, B. et al. Adult mouse epicardium modulates myocardial injury by secreting paracrine factors. J. Clin. Invest. 121, 1894–1904 (2011).

6 Kikuchi, K. et al. Retinoic acid production by endocardium and epicardium is an injury response essential for zebrafish heart regeneration. Dev. Cell 20, 397–404 (2011).

7 Zhou, B. et al. Epicardial progenitors contribute to the cardiomyocyte lineage in the developing heart. Nature 454, 109–113 (2008).

8 Murry, C. E. & Keller, G. Differentiation of embryonic stem cells to clinically relevant populations: lessons from embryonic development. Cell 132, 661–680 (2008).

9 Kattman, S. J. et al. Stage-specific optimization of activin/nodal and BMP signaling promotes cardiac differentiation of mouse and human pluripotent stem cell lines. Cell Stem Cell 8, 228–240 (2011).

10 Lian, X. J. et al. Robust cardiomyocyte differentiation from human pluripotent stem cells via temporal modulation of canonical Wnt signaling. Proc. Natl Acad. Sci. USA 109, E1848–E1857 (2012).

11 Lian, X. et al. Directed cardiomyocyte differentiation from human pluripotent stem cells by modulating Wnt/β-catenin signaling under fully defined conditions. Nat. Protoc. 8, 162–175 (2013).

12 Minami, I. et al. A small molecule that promotes cardiac differentiation of human pluripotent stem cells under defined, cytokine- and xeno-free conditions. Cell Rep. 2, 1448–1460 (2012).

13 Bao, X. et al. Chemically-defined albumin-free differentiation of human pluripotent stem cells to endothelial progenitor cells. Stem Cell Res. 15, 122–129 (2015).

14 Lian, X. et al. Efficient differentiation of human pluripotent stem cells to endothelial progenitors via small-molecule activation of WNT signaling. Stem Cell Rep. 3, 804–816 (2014).

15 Sahara, M. et al. Manipulation of a VEGF-Notch signaling circuit drives formation of functional vascular endothelial progenitors from human pluripotent stem cells. Cell Res. 24, 820–841 (2014).

16 Wang, A. et al. Derivation of smooth muscle cells with neural crest origin from human induced pluripotent stem cells. Cells Tissues Organs 195, 5–14 (2012).

17 Cheung, C., Bernardo, A. S., Trotter, M. W. B., Pedersen, R. A. & Sinha, S. Generation of human vascular smooth muscle subtypes provides insight into embryological origin–dependent disease susceptibility. Nat. Biotechnol. 30, 165–173 (2012).

18 Witty, A. D. et al. Generation of the epicardial lineage from human pluripotent stem cells. Nat. Biotechnol. 32, 1026–1035 (2014).

19 Iyer, D. et al. Robust derivation of epicardium and its differentiated smooth muscle cell progeny from human pluripotent stem cells. Development 142, 1528–1541 (2015).

20 van Tuyn, J. et al. Epicardial cells of human adults can undergo an epithelial-to-mesenchymal transition and obtain characteristics of smooth muscle cells in vitro. Stem Cells 25, 271–278 (2007).

21 Lian, X. et al. Chemically defined, albumin-free human cardiomyocyte generation. Nat. Methods 12, 595–596 (2015).

22 Nakanishi, M. et al. Directed induction of anterior and posterior primitive streak by Wnt from embryonic stem cells cultured in a chemically defined serum-free medium. FASEB J. 23, 114–22 (2009).

23 Zhou, B., von Gise, A., Ma, Q., Rivera-Feliciano, J. & Pu, W. T. Nkx2-5- and Isl1-expressing cardiac progenitors contribute to proepicardium. Biochem. Biophys. Res. Commun. 375, 450–453 (2008).

24 Yu, P. et al. FGF2 sustains NANOG and switches the outcome of BMP4-induced human embryonic stem cell differentiation. Cell Stem Cell 8, 326–334 (2011).

25 Moore, A. W., McInnes, L., Kreidberg, J., Hastie, N. D. & Schedl, A. YAC complementation shows a requirement for Wt1 in the development of epicardium, adrenal gland and throughout nephrogenesis. Development 126, 1845–1857 (1999).

26 Martínez-Estrada, O. M. et al. Wt1 is required for cardiovascular progenitor cell formation through transcriptional control of Snail and E-cadherin. Nat. Genet. 42, 89–93 (2010).

27 Hockemeyer, D. et al. Genetic engineering of human pluripotent cells using TALE nucleases. Nat. Biotechnol. 29, 731–734 (2011).

28 Chen, Y. et al. Engineering human stem cell lines with inducible gene knockout using CRISPR/Cas9. Cell Stem Cell 17, 233–244 (2015).

29 Kofidis, T. et al. Insulin-like growth factor promotes engraftment, differentiation, and functional improvement after transfer of embryonic stem cells for myocardial restoration. Stem Cells 22, 1239–1245 (2004).

30 Engels, M. C. et al. Insulin-like growth factor promotes cardiac lineage induction in vitro by selective expansion of early mesoderm. Stem Cells 32, 1493–1502 (2014).

31 Cao, N. et al. Ascorbic acid enhances the cardiac differentiation of induced pluripotent stem cells through promoting the proliferation of cardiac progenitor cells. Cell Res. 22, 219–236 (2012).

32 Ueno, S. et al. Biphasic role for Wnt/β-catenin signaling in cardiac specification in zebrafish and embryonic stem cells. Proc. Natl Acad. Sci. USA 104, 9685–9690 (2007).

33 David, R. et al. MesP1 drives vertebrate cardiovascular differentiation through Dkk-1-mediated blockade of Wnt-signalling. Nat. Cell Biol. 10, 338–345 (2008).

34 Ruiz-Villalba, A., Ziogas, A., Ehrbar, M. & Pérez-Pomares, J. M. Characterization of epicardial-derived cardiac interstitial cells: differentiation and mobilization of heart fibroblast progenitors. PLoS ONE 8, e53694 (2013).

35 Pérez-Pomares, J. M. et al. Experimental studies on the spatiotemporal expression of WT1 and RALDH2 in the embryonic avian heart: a model for the regulation of myocardial and valvuloseptal development by epicardially derived cells (EPDCs). Dev. Biol. 247, 307–326 (2002).

36 Lian, X. et al. A small molecule inhibitor of SRC family kinases promotes simple epithelial differentiation of human pluripotent stem cells. PLoS ONE 8, e60016 (2013).

37 Garriock, R. J., Mikawa, T. & Yamaguchi, T. P. Isolation and culture of mouse proepicardium using serum-free conditions. Methods 66, 365–369 (2014).

38 Dye, B. R. et al. In vitro generation of human pluripotent stem cell derived lung organoids. eLife 4, e05098 (2015).

39 Tadeu, A. M. B. et al. Transcriptional profiling of ectoderm specification to keratinocyte fate in human embryonic stem cells. PLoS ONE 10, e0122493 (2015).

40 Prasain, N. et al. Differentiation of human pluripotent stem cells to cells similar to cord-blood endothelial colony-forming cells. Nat. Biotechnol. 32, 1151–1157 (2014).

41 Palpant, N. J. et al. Inhibition of β-catenin signaling respecifies anterior-like endothelium into beating human cardiomyocytes. Development 142, 3198–3209 (2015).

42 Bochmann, L. et al. Revealing new mouse epicardial cell markers through transcriptomics. PLoS ONE 5, e11429 (2010).

43 Lian, X., Xu, J., Bao, X. & Randolph, L. N. Interrogating canonical Wnt signaling pathway in human pluripotent stem cell fate decisions using CRISPR-Cas9. Cell. Mol. Bioeng. 9, 325–334 (2016).

44 Lam, J. T., Moretti, A. & Laugwitz, K.-L. Multipotent progenitor cells in regenerative cardiovascular medicine. Pediatr. Cardiol. 30, 690–698 (2009).

45 Winter, E. M. et al. Preservation of left ventricular function and attenuation of remodeling after transplantation of human epicardium-derived cells into the infarcted mouse heart. Circulation 116, 917–927 (2007).

46 Wang, J., Cao, J., Dickson, A. L. & Poss, K. D. Epicardial regeneration is guided by cardiac outflow tract and Hedgehog signalling. Nature 522, 226–230 (2015).

47 Xiao, Y., Liu, K., Shen, J., Xu, G. & Ye, W. SB-431542 inhibition of scar formation after filtration surgery and its potential mechanism. Invest. Ophthalmol. Vis. Sci. 50, 1698–1706 (2009).

48 Phillips, M. D., Mukhopadhyay, M., Poscablo, C. & Westphal, H. Dkk1 and Dkk2 regulate epicardial specification during mouse heart development. Int. J. Cardiol. 150, 186–192 (2011).

49 Bao, X., Lian, X. & Palecek, S. P. Directed endothelial progenitor differentiation from human pluripotent stem cells via Wnt activation under defined conditions. Methods Mol. Biol. 1481, 183–196 (2016).

50 Schmuck, E. G. et al. Cardiac fibroblast-derived 3D extracellular matrix seeded with mesenchymal stem cells as a novel device to transfer cells to the ischemic myocardium. Cardiovasc. Eng. Technol. 5, 119–131 (2014).

51 Kim, D., Langmead, B. & Salzberg, S. L. HISAT: a fast spliced aligner with low memory requirements. Nat. Methods 12, 357–360 (2015).

52 Ramsköld, D., Wang, E. T., Burge, C. B. & Sandberg, R. An abundance of ubiquitously expressed genes revealed by tissue transcriptome sequence data. PLoS Comput. Biol. 5, e1000598 (2009).

53 Subramanian, A. et al. Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles. Proc. Natl Acad. Sci. USA 102, 15545–15550 (2005).