Abstract

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.