PI16 is a shear stress and inflammation-regulated inhibitor of MMP2

Sci Rep. 2016 Dec 20;6:39553. doi: 10.1038/srep39553.


Raised endothelial shear stress is protective against atherosclerosis but such protection may be lost at sites of inflammation. We found that four splice variants of the peptidase inhibitor 16 (PI16) mRNA are among the most highly shear stress regulated transcripts in human coronary artery endothelial cells (HCAECs), in vitro but that expression is reduced by inflammatory mediators TNFα and IL-1β. Immunohistochemistry demonstrated that PI16 is expressed in human coronary endothelium and in a subset of neointimal cells and medial smooth muscle cells. Adenovirus-mediated PI16 overexpression inhibits HCAEC migration and secreted matrix metalloproteinase (MMP) activity. Moreover, PI16 inhibits MMP2 in part by binding an exposed peptide loop above the active site. Our results imply that, at high endothelial shear stress, PI16 contributes to inhibition of protease activity; protection that can be reversed during inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Carrier Proteins / genetics*
  • Cell Movement
  • Coronary Vessels / metabolism*
  • Coronary Vessels / pathology
  • Endothelial Cells / metabolism*
  • Endothelium, Vascular / metabolism
  • Endothelium, Vascular / pathology
  • Gene Expression Regulation*
  • Glycoproteins / genetics*
  • Humans
  • Immunohistochemistry
  • Inflammation*
  • Matrix Metalloproteinase 2 / metabolism*
  • Peptide Library
  • Peptides / chemistry
  • Phenotype
  • Stress, Mechanical
  • Tumor Necrosis Factor-alpha / metabolism


  • Carrier Proteins
  • Glycoproteins
  • PI16 protein, human
  • Peptide Library
  • Peptides
  • TNF protein, human
  • Tumor Necrosis Factor-alpha
  • MMP2 protein, human
  • Matrix Metalloproteinase 2