title: Investigating the spatial distribution of integrin β₁ in patterned human mesenchymal stem cells using super-resolution imaging.
abstract: Lineage commitment of human mesenchymal stem cells (hMSCs) could be directed through micro/nanopatterning of the extracellular matrix (ECM) between cells and substrate. Integrin receptors, integrator of the ECM and cell cytoskeleton, function as molecular bridges linking cells to different biophysical cues translated from patterned ECM. Here we report the distinct recruitment of active integrin β1 (ITG-β1) in hMSCs when they were committed toward the cardiomyogenic lineage on a micropatterned surface. In addition, a systematic study of the distribution of ITG-β1 was performed on focal adhesions (FAs) using a direct stochastic optical reconstruction microscopy (dSTORM) technique, a super-resolution imaging technique to establish the relationship between types of integrin expression and its distribution pattern that are associated with cardiomyogenic differentiation of hMSCs. We ascertained that elongated FAs of ITG-β1 expressed in patterned hMSCs were more prominent than FAs expressed in unpatterned hMSCs. However, there was no significant difference observed between the widths of FAs from both experimental groups. It was found in patterned hMSCs that the direction of FA elongation coincides with cell orientation. This phenomenon was however not observed in unpatterned hMSCs. These results showed that the biophysical induction methods like FAs patterning could selectively induce hMSCs lineage commitment via integrin-material interaction.
authors.affiliation: Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Ajay
authors.initials: A
authors.lastname: Tijore
authors.forename: Srivats
authors.initials: S
authors.lastname: Hariharan
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
authors.forename: Chee Ren Ivan
authors.initials: CR
authors.lastname: Lam
authors.forename: Feng
authors.initials: F
authors.lastname: Wen
authors.forename: Chor Yong
authors.initials: CY
authors.lastname: Tay
authors.forename: Sohail
authors.initials: S
authors.lastname: Ahmed
authors.forename: Lay Poh
authors.initials: LP
authors.lastname: Tan
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D022001:Focal Adhesions; D006801:Humans; D019012:Integrin beta1 / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism*; D057054:Molecular Imaging / Q000379:methods*; D032383:Myocytes, Cardiac; D061848:Optical Imaging / Q000379:methods*; D013269:Stochastic Processes
chemical_list: D015415:Biomarkers; D019012:Integrin beta1
keywords: cardiomyogenic differentiation; focal adhesion; hMSCs; integrin β1; super-resolution imaging