Macromolecular crowding directs extracellular matrix organization and mesenchymal stem cell behavior.
Microenvironments of biological cells are dominated in vivo by macromolecular crowding and resultant excluded volume effects. This feature is absent in dilute in vitro cell culture. Here, we induced macromolecular crowding in vitro by using synthetic macromolecular globules of nm-scale radius at physiological levels of fractional volume occupancy. We quantified the impact of induced crowding on the extracellular and intracellular protein organization of human mesenchymal stem cells (MSCs) via immunocytochemistry, atomic force microscopy (AFM), and AFM-enabled nanoindentation. Macromolecular crowding in extracellular culture media directly induced supramolecular assembly and alignment of extracellular matrix proteins deposited by cells, which in turn increased alignment of the intracellular actin cytoskeleton. The resulting cell-matrix reciprocity further affected adhesion, proliferation, and migration behavior of MSCs. Macromolecular crowding can thus aid the design of more physiologically relevant in vitro studies and devices for MSCs and other cells, by increasing the fidelity between materials synthesized by cells in vivo and in vitro.
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
Adam S
AS
Zeiger
Felicia C
FC
Loe
Ran
R
Li
Michael
M
Raghunath
Krystyn J
KJ
Van Vliet
D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology*; D005362:Ficoll; D006801:Humans; D007150:Immunohistochemistry; D046911:Macromolecular Substances / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D056265:Microbial Interactions / Q000502:physiology*; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D023822:Tissue Engineering / Q000379:methods*
D046911:Macromolecular Substances; D005362:Ficoll