Both hiPSCs and hESCs (>p20) were split at 1:10 or 1:12 ratios, using EDTA as above and grown for 4 days, at which time they reached ~85% confluence. Medium was changed to CDM3, consisting of RPMI 1640 (11875, Life Technologies), 500 µg/mL Oryza sativa-derived recombinant human albumin (A0237, Sigma-Aldrich, 75 mg/mL stock solution in WFI H2O, stored at −20 °C), and 213 µg/mL L-ascorbic acid 2-phosphate (Sigma-Aldrich, 64 mg/mL stock solution in WFI H2O, stored at −20 °C). Medium was changed every other day (48 h). For d0-d2, medium was supplemented with 6 µM CHIR99021 (LC Laboratories). On d2, medium was changed to CDM3 supplemented with 2 µM Wnt-C59 (Selleck Chemicals). Medium was changed on d4 and every other day for CDM3. Contracting cells were noted from d7.
Other additions to cardiac differentiation media tested were 10.7 µg/mL recombinant human transferrin, 14 µg/mL sodium selenite, 1 µg/mL linoleic acid, 1 µg/mL linolenic acid, 2 ng/mL triiodo-l-thyronine, 2 µg/mL L-carnitine, 1 µg/mL D,L-alpha-tocopherol acetate, 100 ng/mL retinol acetate, 1 µg/mL ethanolamine, 20 ng/mL corticosterone, 9 ng/mL progesterone, 47 ng/mL lipoic acid, 100 ng/mL retinol, 1 µg/mL D,L-alpha-tocopherol, 100 ng/mL biotin, 2.5 ug/mL catalase, 2.5 µg/mL glutathione, 2.5 µg/mL superoxide dismutase, 2 µg/mL L-carnitine, 15 µg/mL D(+)-galactose, 16.1 µg/mL putrescine, 450 µM 1-thioglycerol, 55 µM 2-mercaptoethanol, and 64 µg/mL L-ascorbic acid 2-phosphate (all from Sigma-Aldrich).
Basal media assessed were DMEM (catalogue #11965), DMEM/F12 (11330), IMDM (12440), IMDM/F12 (12440/11765), RPMI 1640 (11875), McCoy’s 5A (16600), M199 (with Earle’s Salts, 11150), MEMα (with Earle’s Salts, no nucleosides, 12561), and MEM (with Earle’s Salts, 11095) (all from Life Technologies). RPMI 1640 media assessed were RPMI 1640 with L-glutamine (catalogue number 11875), RPMI 1640 with L-glutamine and HEPES (22400), RPMI 1640 with GlutaMAX (61870), and RPMI with GlutaMAX and HEPES (72400) (all from Life Technologies).
Albumin sources assessed were human serum albumin (A1653, Sigma-Aldrich), Oryza sativa-derived recombinant human albumin (A0237, Sigma-Aldrich), Saccharomyces cerevisiae-derived recombinant Albucult (Novozymes Biopahrma/A6608, Sigma Aldrich), Oryza sativa-derived recombinant Cellastim (Invitria/A9731, Sigma Aldrich), and embryo-grade bovine serum albumin (A3311, Sigma Aldrich).
Wnt inhibitors assessed were IWP-2, IWR-1 (both Sigma-Aldrich), XAV-939, ICG-001 (Selleck Chemicals), IWP-4 (Stemgent), and Wnt-C59 (Selleck Chemicals). GSK3B inhibitors assessed were CHIR99021 (LC Laboratories), BIO, TWS119 (Selleck Chemicals), 1-azenkenpaullone, TDZD-8, ARA014418, and 3F8 (all Sigma-Aldrich). Inhibitors used for pathway analysis were PD173074, SB203580, LDN193189, SB431542 (all Selleck Chemicals), SU5402, Dorsomorphin, A83-01 (all Tocris), ALK5 inhibitor (Stemgent), and ITD-1 (Xcessbio). All small molecules were resuspended to 10 mM in dimethyl sulfoxide (DMSO) and used at 5 µM except for Wnt-C59 which was used at 2 µM.
For control treatments (0 µM) 0.1% DMSO was used. Comparisons of differentiation media were made to RPMI+B27-ins consisting of RPMI 1640 (11875) supplemented with 2% B27 without insulin (0050129SA, Life Technologies), and StemPro-34 (Life Technologies) supplemented as shown inSupplementary Table 1 . LI-APEL low insulin medium and Xeno-free Differentiation Medium were made as described2 (link), 9 (link), 48 (link). For optimization of cardiac differentiation conditions, cells were differentiated in 12-well plates and samples were analyzed at day 15 of differentiation after dissociation with TrypLE Express for 10 min at 37 °C.
Other additions to cardiac differentiation media tested were 10.7 µg/mL recombinant human transferrin, 14 µg/mL sodium selenite, 1 µg/mL linoleic acid, 1 µg/mL linolenic acid, 2 ng/mL triiodo-l-thyronine, 2 µg/mL L-carnitine, 1 µg/mL D,L-alpha-tocopherol acetate, 100 ng/mL retinol acetate, 1 µg/mL ethanolamine, 20 ng/mL corticosterone, 9 ng/mL progesterone, 47 ng/mL lipoic acid, 100 ng/mL retinol, 1 µg/mL D,L-alpha-tocopherol, 100 ng/mL biotin, 2.5 ug/mL catalase, 2.5 µg/mL glutathione, 2.5 µg/mL superoxide dismutase, 2 µg/mL L-carnitine, 15 µg/mL D(+)-galactose, 16.1 µg/mL putrescine, 450 µM 1-thioglycerol, 55 µM 2-mercaptoethanol, and 64 µg/mL L-ascorbic acid 2-phosphate (all from Sigma-Aldrich).
Basal media assessed were DMEM (catalogue #11965), DMEM/F12 (11330), IMDM (12440), IMDM/F12 (12440/11765), RPMI 1640 (11875), McCoy’s 5A (16600), M199 (with Earle’s Salts, 11150), MEMα (with Earle’s Salts, no nucleosides, 12561), and MEM (with Earle’s Salts, 11095) (all from Life Technologies). RPMI 1640 media assessed were RPMI 1640 with L-glutamine (catalogue number 11875), RPMI 1640 with L-glutamine and HEPES (22400), RPMI 1640 with GlutaMAX (61870), and RPMI with GlutaMAX and HEPES (72400) (all from Life Technologies).
Albumin sources assessed were human serum albumin (A1653, Sigma-Aldrich), Oryza sativa-derived recombinant human albumin (A0237, Sigma-Aldrich), Saccharomyces cerevisiae-derived recombinant Albucult (Novozymes Biopahrma/A6608, Sigma Aldrich), Oryza sativa-derived recombinant Cellastim (Invitria/A9731, Sigma Aldrich), and embryo-grade bovine serum albumin (A3311, Sigma Aldrich).
Wnt inhibitors assessed were IWP-2, IWR-1 (both Sigma-Aldrich), XAV-939, ICG-001 (Selleck Chemicals), IWP-4 (Stemgent), and Wnt-C59 (Selleck Chemicals). GSK3B inhibitors assessed were CHIR99021 (LC Laboratories), BIO, TWS119 (Selleck Chemicals), 1-azenkenpaullone, TDZD-8, ARA014418, and 3F8 (all Sigma-Aldrich). Inhibitors used for pathway analysis were PD173074, SB203580, LDN193189, SB431542 (all Selleck Chemicals), SU5402, Dorsomorphin, A83-01 (all Tocris), ALK5 inhibitor (Stemgent), and ITD-1 (Xcessbio). All small molecules were resuspended to 10 mM in dimethyl sulfoxide (DMSO) and used at 5 µM except for Wnt-C59 which was used at 2 µM.
For control treatments (0 µM) 0.1% DMSO was used. Comparisons of differentiation media were made to RPMI+B27-ins consisting of RPMI 1640 (11875) supplemented with 2% B27 without insulin (0050129SA, Life Technologies), and StemPro-34 (Life Technologies) supplemented as shown in