title: Focal adhesion kinase regulation in stem cell alignment and spreading on nanofibers.
abstract: While electrospun nanofibers have demonstrated the potential for novel tissue engineering scaffolds, very little is known about the molecular mechanism of how cells sense and adapt to nanofibers. Here, we revealed the role of focal adhesion kinase (FAK), one of the key molecular sensors in the focal adhesion complex, in regulating mesenchymal stem cell (MSC) shaping on nanofibers. We produced uniaxially aligned and randomly distributed nanofibers from poly(l-lactic acid) to have the same diameters (about 130 nm) and evaluated MSC behavior on these nanofibers comparing with that on flat PLLA control. C3H10T1/2 murine MSCs exhibited upregulations in FAK expression and phosphorylation (pY397) on nanofibrous cultures as assessed by immunoblotting, and this trend was even greater on aligned nanofibers. MSCs showed significantly elongated and well-spread morphologies on aligned and random nanofibers, respectively. In the presence of FAK silencing via small hairpin RNA (shRNA), cell elongation length in the aligned nanofiber direction (cell major axis length) was significantly decreased, while cells still showed preferred orientation along the aligned nanofibers. On random nanofibers, MSCs with FAK-shRNA showed impaired cell spreading resulting in smaller cell area and higher circularity. Our study provides new data on how MSCs shape their morphologies on aligned and random nanofibrous cultures potentially via FAK-mediated mechanism.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors.forename: Mohammad Nahid
authors.initials: MN
authors.lastname: Andalib
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors.forename: Jeong Soon
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors.forename: Ligyeom
authors.initials: L
authors.lastname: Ha
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors.forename: Yuris
authors.initials: Y
authors.lastname: Dzenis
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.|The Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Jung Yul
authors.initials: JY
authors.lastname: Lim
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism* / Q000502:physiology; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000201:enzymology*; D051379:Mice; D057139:Nanofibers / Q000648:ultrastructure
chemical_list: D051416:Focal Adhesion Protein-Tyrosine Kinases
keywords: Aligned and random nanofibers; Cell alignment and spreading; Focal adhesion kinase; Mesenchymal stem cells; shRNA