Nakatani E, Okajima R, Ohnuma K. Slow diffusion on the monolayer culture enhances auto/paracrine effects of Noggin in differentiation of human iPS cells induced by BMP.
Biochem Biophys Rep 2022;
29:101195. [PMID:
35005256 PMCID:
PMC8717143 DOI:
10.1016/j.bbrep.2021.101195]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/30/2022] Open
Abstract
Auto/paracrine factors secreted from cells affect differentiation of human pluripotent stem cells (hPSCs). However, the molecular mechanisms underlying the role of secreted factors are not well known. We previously showed that pattern formation in hPSCs induced by BMP4 could be reproduced by a simple reaction-diffusion of BMP and Noggin, a cell-secreted BMP4 inhibitor. However, the amount of Noggin secreted is unknown.
In this study, we measured the concentration of Noggin secreted during the differentiation of hPSCs induced by BMP4. The Noggin concentration in the supernatant before and after differentiation was constant at approximately 0.69 ng/mL, which is approximately 50–200 times less than expected in the model. To explain the difference between the experiment and model, we assumed that macromolecules such as heparan sulfate proteoglycan on the cell surface act as a diffusion barrier structure, where the diffusion slows down to 1/400. The model with the diffusion barrier structure reduced the Noggin concentration required to suppress differentiation in the static culture model. The model also qualitatively reproduced the pattern formation, in which only the upstream but not the downstream hPSCs were differentiated in a one-directional perfusion culture chamber, with a small change in the amount of secreted Noggin resulting in a large change in the differentiation position. These results suggest that the diffusion barrier on the cell surface might enhance the auto/paracrine effects on monolayer hPSC culture.
Noggin was constantly secreted at about 0.69 ng/mL irrespective of cell state.
Noggin concentration was 1/145 than expected in the mere diffusion-reaction model.
Slow diffusion on the cell surface reduced the Noggin concentration in the medium.
The diffusion barrier reproduced pattern formation in the microchamber.
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