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Improved Pancreatic Differentiation Via Cytoskeletal Targeting

Review of “Targeting the cytoskeleton to direct pancreatic differentiation of human pluripotent stem cells” from Nature Biotechnology by Stuart P. Atkinson

The differentiation of large numbers of fully functional pancreatic β cells from cultures of human pluripotent stem cells (hPSCs) remains a difficult task; however, researchers from the laboratory of Jeffrey R. Millman (Washington University in St. Louis, St. Louis, MO, USA) recently took a huge step forward by generating highly functional hPSC-derived pancreatic β cells using a simple, two-dimensional culture protocol. Furthermore, in their recent Nature Biotechnology study, the authors established a link between the state of the actin cytoskeleton and the expression of pancreatic transcription factors that drive pancreatic lineage specification [1].

Hogrebe et al. used RNA-sequencing analysis to establish a link between different degrees of actin polymerization and endodermal lineage bias during the differentiation of hPSCs to pancreatic β cells, and in doing so, they discovered that conditions favoring a polymerized cytoskeleton strongly inhibited the NGN3 [2]-induced endocrine differentiation of PDX1-expressing pancreatic progenitors. These findings suggested to the team that the state of the actin cytoskeleton alters the timing of endocrine transcription factor expression and hence can alter the differentiation process.

With this knowledge in hand, the authors integrated the depolymerization of the cytoskeleton during endocrine induction of pancreatic progenitor cells through the addition latrunculin A, which binds and sequesters monomeric actin [3], into a two-dimensional differentiation protocol for the generation of hPSC-derived β cells with improved function in vitro and in vivo. Specifically, the hPSC-derived β cells differentiated in this manner exhibited first- and second-phase dynamic glucose-stimulated insulin secretion, while the transplantation of islet-sized hPSC-derived β cells aggregates reversed severe preexisting diabetes in model mice at a rate comparable to human islets. Of note, these mice maintained normal blood glucose levels for at least nine months. 

Overall, the generation of pancreatic β cells without the need for three-dimensional culture, a complicated and often expensive venture [4, 5], provides for a more straightforward approach to the large-scale differentiation of hPSCs, and therefore, represents a more adaptable strategy regarding clinical and industrial concerns.

For more on how modulating cytoskeletal dynamics could improve your hPSC differentiation protocol, stay tuned for all the relevant studies here on the Stem Cells Portal!

References

  1. Hogrebe NJ, Augsornworawat P, Maxwell KG, et al., Targeting the Cytoskeleton to Direct Pancreatic Differentiation of Human Pluripotent Stem Cells. Nature Biotechnology 2020;38:460-470.
  2. Gu G, Dubauskaite J, and Melton DA, Direct Evidence for the Pancreatic Lineage: NGN3+ Cells are Islet Progenitors and are Distinct from Duct Progenitors. Development 2002;129:2447.
  3. Coué M, Brenner SL, Spector I, et al., Inhibition of Actin Polymerization by Latrunculin A. FEBS Letters 1987;213:316-318.
  4. Pagliuca Felicia W, Millman Jeffrey R, Gürtler M, et al., Generation of Functional Human Pancreatic β cells In Vitro. Cell 2014;159:428-439.
  5. Rezania A, Bruin JE, Arora P, et al., Reversal of Diabetes with Insulin-producing Cells Derived in vitro from Human Pluripotent Stem Cells. Nature Biotechnology 2014;32:1121-1133.