title: Correlation between in vitro expansion-related cell stiffening and differentiation potential of human mesenchymal stem cells.
abstract: Human mesenchymal stem cells (hMSCs) are an attractive cell source for tissue regeneration, given their self-renewal and multilineage potential. However, they are present in only small percentages in human bone marrow, and are generally propagated in vitro prior to downstream use. Previous work has shown that hMSC propagation can lead to alterations in cell behavior and differentiation potency, yet optimization of differentiation based on starting cell elastic modulus is an area still under investigation. To further advance the knowledge in this field, hMSCs were cultured and routinely passaged on tissue-culture polystyrene to investigate the correlation between cell stiffening and differentiation potency during in vitro aging. Local cell elastic modulus was measured at every passage using atomic force microscopy indentation. At each passage, cells were induced to differentiate down myogenic and osteogenic paths. Cells induced to differentiate, as well as undifferentiated cells were assessed for gene and protein expression using quantitative polymerase chain reaction and immunofluorescent staining, respectively, for osteogenic and myogenic markers. Myogenic and osteogenic cell potential are highly reliant on the elastic modulus of the starting cell population (of undifferentiated cells), and this potential appears to peak when the innate cell elastic modulus is close to that of differentiated tissue. However, the latent expression of the same markers in undifferentiated cells also appears to undergo a correlative relationship with cell elastic modulus, indicating some endogenous effects of cell elastic modulus and gene/protein expression. Overall, this study correlates age-related changes with regards to innate cell stiffening and gene/protein expression in commercial hMSCs, providing some guidance as to maintenance and future use of hMSCs in future tissue engineering applications.
authors.affiliation: Mechanical Engineering & Mechanics, Packard Laboratory, Lehigh University, 19 Memorial Drive, Bethlehem, PA 18015, United States.
authors.forename: Courtney E
authors.initials: CE
authors.lastname: LeBlon
authors.affiliation: Bioengineering Program, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, United States.
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Casey
authors.affiliation: Bioengineering Program, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, United States.
authors.forename: Caitlin R
authors.initials: CR
authors.lastname: Fodor
authors.affiliation: Bioengineering Program, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, United States.
authors.forename: Tony
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Mechanical Engineering & Mechanics, Packard Laboratory, Lehigh University, 19 Memorial Drive, Bethlehem, PA 18015, United States; Bioengineering Program, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, United States.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Bioengineering Program, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, United States; Materials Science and Engineering, Whitaker Laboratory, Lehigh University, 5 East Packer Ave., Bethlehem, PA 18015, United States; Center for Advanced Materials & Nanotechnology, Whitaker Laboratory, Lehigh University, 5 East Packer Ave., Bethlehem, PA 18015, United States. Electronic address: ssj207@lehigh.edu.
authors.forename: Sabrina S
authors.initials: SS
authors.lastname: Jedlicka
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D016922:Cellular Senescence; D055119:Elastic Modulus; D015870:Gene Expression; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D018625:Microscopy, Atomic Force; D024510:Muscle Development; D010012:Osteogenesis; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D022502:Stress Fibers; D023822:Tissue Engineering
chemical_list: D015415:Biomarkers; D011506:Proteins
keywords: Endogenous gene expression; Human mesenchymal stem cells; In vitro aging; Local elastic modulus; Myogenesis; Osteogenesis