title: Cyclic strain enhances matrix mineralization by adult human mesenchymal stem cells via the extracellular signal-regulated kinase (ERK1/2) signaling pathway.
abstract: Physical stimuli play critical roles in the development, regeneration, and pathology of many mesenchymal tissues, most notably bone. While mature bone cells, such as osteoblasts and osteocytes, are clearly involved in these processes, the role of their progenitors in mechanically mediated tissue responses is unknown. In this study, we investigated the effect of cyclic substrate deformation on the proliferation and osteogenic differentiation of human mesenchymal stem cells (hMSCs). Application of equibiaxial cyclic strain (3%, 0.25Hz) to hMSCs cultured in osteogenic media inhibited proliferation and stimulated a 2.3-fold increase in matrix mineralization over unstrained cells. The strain stimulus activated the extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein kinase pathways, but had no effect on c-Jun N-terminal kinase phosphorylation or activity. Strain-induced mineralization was largely mediated by ERK1/2 signaling, as inhibition of ERK1/2 attenuated calcium deposition by 55%. Inhibition of the p38 pathway resulted in a more mature osteogenic phenotype, suggesting an inhibitory role for p38 signaling in the modulation of strain-induced osteogenic differentiation. These results demonstrate that mechanical signals regulate hMSC function, suggesting a critical role for physical stimulation of this specific cell population in mesenchymal tissue formation.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Simmons
authors.forename: Sean
authors.initials: S
authors.lastname: Matlis
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Thornton
authors.forename: Shaoqiong
authors.initials: S
authors.lastname: Chen
authors.forename: Cun Yu
authors.initials: CY
authors.lastname: Wang
authors.forename: David J
authors.initials: DJ
authors.lastname: Mooney
mesh_terms: D000328:Adult; D002113:Calcification, Physiologic / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000502:physiology*; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009068:Movement; D010012:Osteogenesis / Q000502:physiology*; D010507:Periodicity; D010812:Physical Stimulation / Q000379:methods*; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases