Basic Study
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World J Stem Cells. Aug 26, 2022; 14(8): 616-632
Published online Aug 26, 2022. doi: 10.4252/wjsc.v14.i8.616
Changes of cell membrane fluidity for mesenchymal stem cell spheroids on biomaterial surfaces
Chui-Wei Wong, Hao-Wei Han, Shan-hui Hsu
Chui-Wei Wong, Hao-Wei Han, Shan-hui Hsu, National Taiwan University, Institute of Polymer Science and Engineering, Taipei 10617, Taiwan
Shan-hui Hsu, National Health Research Institutes, Institute of Cellular and System Medicine, Miaoli 350, Taiwan
Shan-hui Hsu, National Taiwan University, Research and Development Center for Medical Devices, Taipei 10617, Taiwan
Author contributions: Wong CW and Han HW designed and coordinated the study, performed the experiments, acquired and interpreted the data, and wrote the original draft; Hsu Sh contributed to the conceptualization, investigation, review, editing and supervision; All authors approved the final version of the article.
Supported by National Taiwan University Core Consortium, No. NTU-CC-110L892501; and Ministry of Science and Technology, No. MOST 110-2218-E-002-037.
Institutional review board statement: The study does not meet the definition of a human subject and does not require an institutional review board statement review at National Taiwan University.
Institutional animal care and use committee statement: No animal study in the manuscript.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Shan-hui Hsu, PhD, Professor, National Taiwan University, Institute of Polymer Science and Engineering, No. 1 Sec. 4 Roosevelt Road, Taipei 10617, Taiwan. shhsu@ntu.edu.tw
Received: March 5, 2022
Peer-review started: March 5, 2022
First decision: April 19, 2022
Revised: May 2, 2022
Accepted: July 8, 2022
Article in press: July 8, 2022
Published online: August 26, 2022
Processing time: 174 Days and 3.5 Hours
Abstract
BACKGROUND

The therapeutic potential of mesenchymal stem cells (MSCs) in the form of three-dimensional spheroids has been extensively demonstrated. The underlying mechanisms for the altered cellular behavior of spheroids have also been investigated. Cell membrane fluidity is a critically important physical property for the regulation of cell behavior, but it has not been studied for the spheroid-forming cells to date.

AIM

To explore the association between cell membrane fluidity and the morphological changes of MSC spheroids on the surface of biomaterials to elucidate the role of membrane fluidity during the spheroid-forming process of MSCs.

METHODS

We generated three-dimensional (3D) MSC spheroids on the surface of various culture substrates including chitosan (CS), CS-hyaluronan (CS-HA), and polyvinyl alcohol (PVA) substrates. The cell membrane fluidity and cell morphological change were examined by a time-lapse recording system as well as a high-resolution 3D cellular image explorer. MSCs and normal/cancer cells were pre-stained with fluorescent dyes and co-cultured on the biomaterials to investigate the exchange of cell membrane during the formation of heterogeneous cellular spheroids.

RESULTS

We discovered that vesicle-like bubbles randomly appeared on the outer layer of MSC spheroids cultured on different biomaterial surfaces. The average diameter of the vesicle-like bubbles of MSC spheroids on CS-HA at 37 °C was approximately 10 μm, smaller than that on PVA substrates (approximately 27 μm). Based on time-lapse images, these unique bubbles originated from the dynamic movement of the cell membrane during spheroid formation, which indicated an increment of membrane fluidity for MSCs cultured on these substrates. Moreover, the membrane interaction in two different types of cells with similar membrane fluidity may further induce a higher level of membrane translocation during the formation of heterogeneous spheroids.

CONCLUSION

Changes in cell membrane fluidity may be a novel path to elucidate the complicated physiological alterations in 3D spheroid-forming cells.

Keywords: Cell membrane fluidity; Cell-cell interaction; Cellular spheroids; Chitosan; Hyaluronan

Core Tip: The fluidity of the cell membrane is an important physical property for the regulation of cell behavior. To date, the changes in cell membrane fluidity are not fully understood in spheroid-forming cells. In this study, various substrates were utilized to grow mesenchymal stem cells and to form homotypic or heterotypic cellular spheroids on the substrates. During the spheroid-forming process, vesicle-like bubbles were randomly generated on the cell membrane. The evidence suggests that the physiological alterations of cells after they form cellular spheroids may be associated with changes in membrane fluidity during the spheroid-forming process.