Wnt signalling proteins are essential for culture of human organ stem cells in organoids, but most Wnt protein formulations are poorly active in serum-free media. Here we show that purified Wnt3a protein is ineffective because it rapidly loses activity in culture media due to its hydrophobic nature, and its solubilization requires a detergent, CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate), that interferes with stem cell self-renewal. By stabilizing the Wnt3a protein using phospholipids and cholesterol as carriers, we address both problems: Wnt activity remains stable in serum-free media, while non-toxic carriers allow the use of high Wnt concentrations. Stabilized Wnt3a supports strongly increased self-renewal of organ and embryonic stem cells and the serum-free establishment of human organoids from healthy and diseased intestine and liver. Moreover, the lipophilicity of Wnt3a protein greatly facilitates its purification. Our findings remove a major obstacle impeding clinical applications of adult stem cells and offer advantages for all cell culture uses of Wnt3a protein.

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Persistent URL dx.doi.org/10.1038/ncomms14578, hdl.handle.net/1765/98541
Journal Nature Communications
Tüysüz, N, Van Bloois, L. (Louis), Van Den Brink, S. (Stieneke), Begthel, H, Verstegen, M.M.A, Cruz, L.J. (Luis J.), … ten Berge, D. (2017). Lipid-mediated Wnt protein stabilization enables serum-free culture of human organ stem cells. Nature Communications, 8. doi:10.1038/ncomms14578