. 2015 Jul 29;16(8):17368–17393. doi: 10.3390/ijms160817368

Table 1.

Direct cardiac reprogramming in vitro (mouse).

Reference	Cell Source	Reprogramming Factors	Markers of iCMs, Percentages		Spontaneous Beating/When	Comments
[15]	MCFs, TTFs	Starting with 14 F: GMT best	αMHC-GFP + TropT (FACS, day 7)		MCFs: yes, after 4–5 weeks (rare events)	No CPC stage
			MCFs:	GMT: ~4%–6%
			TTFs:	GMT: ~2.5%
[22]	aMCFs, aTTFs	H₂GMT	αMHC-GFP + TropT (FACS)		aMCFs: yes, after 5 weeks (rare events) aTTFs: yes, after 5 weeks (rare events)	–
			aTTFs (day 9):	GMT: ~2.9%
			aTTFs (day 9):	H₂GMT: ~9.2%
			aMCFs (day 7):	GMT: ~1.4%
			aMCFs (day 7):	H₂GMT: ~6.8%
[23]	aMCFs, aTTFs	GMT	αMHC-GFP; Nkx2.5-GFP (FACS, day 21): no GFP+ cells		No beating	no CPC stage (Nkx2.5-GFP)
[21]	MEFs (E13.5, w/o head, w/o visceral organs, p3–p5) MCFs (aMHC-tdTomato mice: Thy1⁺, tdTomato^-) TTFs (3-day-old mice)	MTMc	MEFs: for initial qRT-PCR screening		MCFs: no, after 4 weeks (only rare events which were considered as cardiomyocyte contamination)	–
			αMHC-tdTomato (FACS, day 14)
			MCFs:	GMT: 2.2% ± 0.2%
			MCFs:	MTMc: 2.5% ± 0.3%
			TTFs:	GMT: 2.4% ± 0.2%
			TropT (FACS, day 14)
			MCFs:	GMT: 12% ± 3.7%
			MCFs:	MTMc: 11% ± 2.0%
[24]	MCFs	miR-1, miR-133, miR-208, miR-499 + JI1	αMHC-CFP (FACS, day 7)		MCFs: yes, after 10 days (rare events 1%–2% of total cell population)	short CPC stage: Mesp2 from day 1–5 (miR-1, -133, -208, -499); no pluripotency marker detected (Oct4, Nanog)
			negmiR: 0.1%–3.9%
			miR-1, -133, -208, -499: 1.1%–5.3%
			negmiR + JI1: 0.3%–1.7%
			miR-1, -133, -208, -499 + JI1: 13.4%–27.9%
[25]	MEFs (E14.5, w/o head, w/o visceral organs, w/o heart, p3–p5) aMCFs (8–10-week-old mice), isolation by culture, p3	NH₂GMT	TropT-GCaMP (Ca²⁺ oscillation, day 14)		MEFs: yes, after day 14	iCMs not proliferative (Ki67)
			MEFs:	GMT: 0.03% ± 0.02%
			MEFs:	NH₂GMT: 1.6% ± 0.3%
			MCFs:	NH₂GMT: 4.5% ± 0.3%
[26]	MEFs (E13)	MpScMcSfNH₁H₂GTM	αMHC-GFP (FACS, day 7)		N.A.	–
			NegCtr: 0.03% ± 0.05%
			GMT: 0.05% ± 0.06%
			GMTMcSf: 1.60% ± 0.12%
			GMTMpSc: 0.20% ± 0.07%
			GMTMcSfMpSc: 2.40% ± 0.11%
[27]	MEFs (E14.5, w/o head, w/o visceral organs, w/o heart), p3–p5 aMCFs (8–10-week-old mice), isolation by culture, p3	NH₂GMT + small molecules (SB)	TropT-GCaMP (Ca²⁺ oscillation, day 14)		MEFs: robust beating, after day 11 aMCFs: yes, after day 16	TGFβ signaling pathway plays a role in conversion
			MEFs:	NH₂GMT + DMSO: 5.0% ± 1.8%
			MEFs:	NH₂GMT + SB: 17.0% ± 0.4%
			aMCFs:	NH₂GMT + DMSO: 1.5% ± 0.4%
			aMCFs:	NH₂GMT + SB (5 µM): 9.3% ± 1.3%
[9]	MEFs (E12.5, w/o head, w/o visceral organs) aMCFs (adult αMHC-GFP mice; Thy1⁺ GFP⁻)	GMT + miR133	αMHC-GFP (FACS, day 7)		MEFs: GMT: yes, after 4 weeks; GMT + miR133: yes, after 10 days aMCFs: N.A.	iCMs not proliferative (EdU assay) Snai1/EMT mechanism no Mesp1+ CPCs (Mesp1-Cre x Stop-GFP mouse MEFs) mainly atrial-type myocytes
			MEFs:	GMT: ~19%; GMT + miR133: ~33%
			TropT (FACS, day 7)
			MEFs:	GMT: ~1.9%; GMT + miR133: ~12%
[28]	MEFs, TTFs, MCFs	20 F H₂GMT	Hcn4-GFP (FACS, day 7)		No (due to inadequate sarcomeric protein expression and organization, 12 weeks of culture) 0.0%–0.16% of H₂GMT transduced fibroblasts show spontaneous beating (no further specification)	No Nkx2.5+ CPCs; well organized sarcomeric structures necessary for spontaneous beating, H₂GMT: different types of CMs (atrial, pacemaker, and ventricular)
			TTFs:	20F: 15%;
				G₆T₃TR: ~40%
				H₂GMT: N.A.
[29]	MCFs (1.5 day old mice), TTFs	GMT (polycistronic vector, different order)	αMHC-GFP or TropT (FACS, day 10)		MCFs: MGT: yes, after 3 weeks	Stoichiometry is of critical importance (especially high Mef2c levels)
			MCFs:	G + M + T: ~5% (GFP), ~0.2% (TropT)
				GMT: ~1% (GFP), 0.02% (TropT)
				MGT: ~10% (GFP), ~4.8% (TropT)
				MTG: ~9% (GFP), ~3.5% (TropT)
[30] CASD approach	MEFs, TTFs	OSKMy + cytokines + small molecules	Nebulette-LacZ: initial screening		MEFs: yes, after day 11 TTFs: yes, after day 12 beating patches generated per 100,000 cells on day 18 MEFs: 145 ± 6 TTFs: 115 ± 7	CPC stage: on day 9–10 (Flk1, Nkx2.5, Gata4) day 11: only atrial CMs only Mlc2a not Mlc2v
			MEFs: OSK + JI1 (day 1–day 9) + BMP4 (day 9–day 14): N.A.
			TropT (FACS, day 18)
			TTFs: OSKM + JI1 (day1–day9) + BMP4 (day 9–day 14), 39% ± 2%
[31] CASD approach	MEFs (E13.5, w/o head, w/o visceral organs, w/o heart), TTFs	Oct4 + small molecules (SCPF) + BMP4	Beating cluster (day 30)		MEFs: yes, after day 20 TTFs: yes	CPC stage mostly ventricular iCMs (Mlc2v)
			MEFs: 99 ± 17 per 10,000 starting cells
			TTFs: ~50 per 10,000 starting cells

Abbreviations: iCMs, induced cardiomyocytes; CASD, Cell-Activation and Signaling-Directed; Cell Source, MEFs: murine embryonic fibroblasts; MCFs, murine cardiac fibroblasts; TTFs, tail-tip fibroblasts; a, adult; w/o, without; p, passage; Reprogramming Factors, F: factors; O, Oct4; S, Sox2; K, Klf4; My, c-Myc; H₂, Hand2; N, Nkx2.5; G, Gata4; G₆, Gata6; M, Mef2c; T, Tbx5; T₃, Tbx3; Mc, Myocardin; Mp, Mesp1; Sc, Smarcd3 (Baf60c); Sf, SRF; H₁, Hand1; E, ESRRG; Z, ZFPM2; R, Rxra; JI1, JAK inhibitor JI1; BMP4, bone morphogenic protein 4; SB, SB431542 (TGFβ-inhibitor); S, SB431542 (ALK4/5/7 inhibitor); C, CHIR99021 (GSK3 inhibitor); P, parnate (LSD1/KDM1 inhibitor); F, forskolin (adenylyl cyclase activator); Comments: CPC, cardiac progenitor cell. N.A., not available; bold text, markers for iCMs and used cell sources.