期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2014
卷号：111
期号：42
页码：E4409-E4418
DOI：10.1073/pnas.1402306111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceWe identify a set of unique biophysical markers of multipotent mesenchymal stromal cell populations. Multivariate biophysical analysis of cells from 10 adult and fetal bone marrow donors shows that distinct subpopulations exist within supposed mesenchymal stem cell populations that are otherwise indistinguishable by accepted stem cell marker surface antigens. We find that although no single biophysical parameter is wholly predictive of stem cell multipotency, three of these together--cell diameter, cell mechanical stiffness, and nuclear membrane fluctuations--distinguish multipotent stem cell from osteochondral progenitor subpopulations. Together, these results (along with the corresponding statistical correlations) show that a minimal set of biophysical markers can be used to identify, isolate, and predict the function of stem and progenitor cells within mixed cell populations. The capacity to produce therapeutically relevant quantities of multipotent mesenchymal stromal cells (MSCs) via in vitro culture is a common prerequisite for stem cell-based therapies. Although culture expanded MSCs are widely studied and considered for therapeutic applications, it has remained challenging to identify a unique set of characteristics that enables robust identification and isolation of the multipotent stem cells. New means to describe and separate this rare cell type and its downstream progenitor cells within heterogeneous cell populations will contribute significantly to basic biological understanding and can potentially improve efficacy of stem and progenitor cell-based therapies. Here, we use multivariate biophysical analysis of culture-expanded, bone marrow-derived MSCs, correlating these quantitative measures with biomolecular markers and in vitro and in vivo functionality. We find that, although no single biophysical property robustly predicts stem cell multipotency, there exists a unique and minimal set of three biophysical markers that together are predictive of multipotent subpopulations, in vitro and in vivo. Subpopulations of culture-expanded stromal cells from both adult and fetal bone marrow that exhibit sufficiently small cell diameter, low cell stiffness, and high nuclear membrane fluctuations are highly clonogenic and also exhibit gene, protein, and functional signatures of multipotency. Further, we show that high-throughput inertial microfluidics enables efficient sorting of committed osteoprogenitor cells, as distinct from these mesenchymal stem cells, in adult bone marrow. Together, these results demonstrate novel methods and markers of stemness that facilitate physical isolation, study, and therapeutic use of culture-expanded, stromal cell subpopulations.
