title: Quantifying cellular mechanics and adhesion in renal tubular injury using single cell force spectroscopy.
abstract: Tubulointerstitial fibrosis represents the major underlying pathology of diabetic nephropathy where loss of cell-to-cell adhesion is a critical step. To date, research has predominantly focussed on the loss of cell surface molecular binding events that include altered protein ligation. In the current study, atomic force microscopy single cell force spectroscopy (AFM-SCFS) was used to quantify changes in cellular stiffness and cell adhesion in TGF-β1 treated kidney cells of the human proximal tubule (HK2). AFM indentation of TGF-β1 treated HK2 cells showed a significant increase (42%) in the elastic modulus (stiffness) compared to control. Fluorescence microscopy confirmed that increased cell stiffness is accompanied by reorganization of the cytoskeleton. The corresponding changes in stiffness, due to F-actin rearrangement, affected the work of detachment by changing the separation distance between two adherent cells. Overall, our novel data quantitatively demonstrate a correlation between cellular elasticity, adhesion and early morphologic/phenotypic changes associated with tubular injury.
  
  
  BACKGROUND
  Diabetes affects many patients worldwide. One of the long term problems is diabetic nephropathy. Here, the authors utilized atomic force microscopy single cell force spectroscopy (AFM- SCFS) to study cellular stiffness and cell adhesion after TGF1 treatment in human proximal tubule kidney cells. The findings would help further understand the overall disease mechanism in diabetic patients.
authors.affiliation: School of Engineering, University of Warwick, Coventry, UK.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Siamantouras
authors.affiliation: School of Life Sciences, University of Lincoln, Lincoln, UK.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Hills
authors.affiliation: School of Life Sciences, University of Lincoln, Lincoln, UK.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Squires
authors.affiliation: School of Engineering, University of Warwick, Coventry, UK. Electronic address: I.K.Liu@warwick.ac.uk.
authors.forename: Kuo-Kang
authors.initials: KK
authors.lastname: Liu
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects*; D003928:Diabetic Nephropathies / Q000188:drug therapy / Q000473:pathology*; D004548:Elasticity; D005355:Fibrosis / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018625:Microscopy, Atomic Force; D059010:Single-Cell Analysis; D013314:Stress, Mechanical; D053773:Transforming Growth Factor beta1 / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D000199:Actins; D053773:Transforming Growth Factor beta1
keywords: Atomic force microscopy; Cell elasticity; Fibrosis; Nanomechanics; TGF-β1