Kindlin-2 Mediates Mechanical Activation of Cardiac Myofibroblasts

Cells. 2020 Dec 17;9(12):2702. doi: 10.3390/cells9122702.


We identify the focal adhesion protein kindlin-2 as player in a novel mechanotransduction pathway that controls profibrotic cardiac fibroblast to myofibroblast activation. Kindlin-2 is co-upregulated with the myofibroblast marker α-smooth muscle actin (α-SMA) in fibrotic rat hearts and in human cardiac fibroblasts exposed to fibrosis-stiff culture substrates and pro-fibrotic TGF-β1. Stressing fibroblasts using ferromagnetic microbeads, stretchable silicone membranes, and cell contraction agonists all result in kindlin-2 translocation to the nucleus. Overexpression of full-length kindlin-2 but not of kindlin-2 missing a putative nuclear localization sequence (∆NLS kindlin-2) results in increased α-SMA promoter activity. Downregulating kindlin-2 with siRNA leads to decreased myofibroblast contraction and reduced α-SMA expression, which is dependent on CC(A/T)-rich GG(CArG) box elements in the α-SMA promoter. Lost myofibroblast features under kindlin-2 knockdown are rescued with wild-type but not ∆NLS kindlin-2, indicating that myofibroblast control by kindlin-2 requires its nuclear translocation. Because kindlin-2 can act as a mechanotransducer regulating the transcription of α-SMA, it is a potential target to interfere with myofibroblast activation in tissue fibrosis.

Keywords: fibrosis; focal adhesion; mechanical stress; mechanosensation; nuclear shuttling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Adult
  • Animals
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Humans
  • Male
  • Mechanotransduction, Cellular*
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Microscopy, Fluorescence
  • Myofibroblasts / cytology
  • Myofibroblasts / drug effects
  • Myofibroblasts / metabolism*
  • Neoplasm Proteins / antagonists & inhibitors
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Promoter Regions, Genetic
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Rats
  • Transforming Growth Factor beta1 / pharmacology


  • ACTA2 protein, human
  • Actins
  • FERMT3 protein, human
  • Membrane Proteins
  • Neoplasm Proteins
  • RNA, Small Interfering
  • Transforming Growth Factor beta1