Generation of cardiomyocytes from human pluripotent stem cells
Methods for generating high-yield, high-purity cardiomyocyte progenitors or cardiomyocytes from pluripotent cells are described. Wnt/β-catenin signaling is first activated in pluripotent cells, e.g., by inhibition of Gsk-3 to obtain a first population of cells. Wnt/β-catenin signaling is then inhibited in the first cell population to induce cardiogenesis under fully defined, growth factor free culture conditions.
1. A method for generating a cell population of human cardiomyocyte progenitors, comprising inhibiting Wnt/β-catenin signaling in a first cell population to obtain a second cell population comprising human cardiomyocyte progenitors, wherein inhibiting comprises culturing the first cell population in the presence of an inhibitor of Wnt/β-catenin signaling, wherein the culturing is substantially free of exogenous growth factors, and wherein the first cell population is obtained by activating Wnt/β-catenin signaling in human pluripotent stem cells by culturing the human pluripotent stem cells in the presence of a Gsk3 inhibitor.
2. The method of claim 1 , wherein the first cell population comprises cells that overexpress β-catenin.
3. The method of claim 2 , wherein β-catenin overexpression is inducible.
4. The method of claim 1 , wherein the Gsk3 inhibitor is a small molecule selected from the group consisting of CHIR 99021, CHIR 98014, BIO-acetoxime, BIO, LiCl, SB 216763, SB 415286, AR A014418, 1-Azakenpaullone, and Bis-7-indolylmaleimide, or a combination thereof.
5. The method of claim 1 , wherein the Gsk3 inhibitor comprises a Gsk3-targeting short interfering RNA (siRNA) polynucleotide.
6. The method of claim 5 , wherein the Gsk3-targeting siRNA is inducible.
7. The method of claim 1 , wherein the inhibitor of Gsk3 is a dominant negative form of Gsk3.
8. The method of claim 1 , wherein the step of inhibiting Wnt/β-catenin signaling comprises culturing the first cell population in the presence of a small molecule that inhibits Wnt/β-catenin signaling.
9. The method of claim 8 , wherein the small molecule that inhibits Wnt/β-catenin signaling is selected from the group consisting of XAV939, IWR-1, IWR-2, IWR-3, IWR-4, IWR-5, IWP-1, IWP-2, IWP-3, and IWP-4.
10. The method of claim 9 , wherein the small molecule that inhibits Wnt/β-catenin signaling is XAV939.
11. The method of claim 8 , wherein the small molecule prevents palmitoylation of Wnt proteins by Porcupine (Porcn).
12. The method of claim 11 , wherein the small molecule that prevents palmitoylation of Wnt proteins by Porcn is selected from the group consisting of IWP-2 and IWP-4.
13. The method of claim 1 , wherein the step of inhibiting Wnt/β-catenin signaling comprises contacting the first cell population with at least one antibody that blocks activation of a Wnt ligand receptor.
14. The method of claim 13 , wherein the at least one antibody binds to one or more Wnt ligand family members.
15. The method of claim 1 , wherein the step of inhibiting Wnt/β-catenin signaling comprises reducing β-catenin expression in the first cell population.
16. The method of claim 15 , wherein reducing β-catenin expression comprises expressing a β-catenin-targeting short hairpin RNA (shRNA) in the first cell population.
17. The method of claim 16 , wherein the β-catenin-targeting shRNA is inducible.
18. The method of claim 1 , wherein at least one of the first cell population and the second population is cultured under conditions free of exogenous growth factors.
19. The method of claim 1 , further comprising culturing the second cell population in the substantial absence of exogenous growth factors after ending the inhibition of Wnt/β-catenin signaling to obtain a cell population comprising cardiomyocytes.
20. The method of claim 19 , wherein the culturing comprises culturing in a medium comprising RPMI base medium, wherein at least 70% of the cells in the cell population comprising cardiomyocytes are cardiac troponinT (cTnT)-positive.
21. The method of claim 20 , wherein the cell population comprising at least 70% cTnT-positive cells is obtained without a cell separation or selection step.