Matrilysin (MMP-7) catalytic activity regulates β-catenin localization and signaling activation in lung epithelial cells

Exp Lung Res. 2014 Apr;40(3):126-36. doi: 10.3109/01902148.2014.890681.

Abstract

Matrix metalloproteinase-7 (matrilysin, MMP-7) expression is increased in epithelium by bacterial infection, inflammation, fibrosis, and in a myriad of carcinomas. It functions to degrade extracellular matrix and other pericellular substrates including the adherens junction protein E-cadherin to promote wound healing and tissue remodeling. β-catenin functions as both a structural component of adherens junctions and as an intracellular signaling molecule. To assess if matrilysin-mediated disassembly of adherens junctions regulates β-catenin function, we assessed effects of matrilysin catalytic activity on β-catenin localization and signaling activity in A549 cells and in bleomycin-induced lung injury in mice. We determined that matrilysin activity releases β-catenin from the cell membrane after which it is degraded in the cytosol. However, in the presence of a β-catenin stabilizing Wnt signal, β-catenin accumulated in the cytosol and activated a β-catenin luciferase promoter. Furthermore, β-catenin nuclear translocation and activation was impaired in matrilysin-null mice when compared to wild-type mice after bleomycin-induced lung injury. These results show identify matrilysin as a regulator of β-catenin function in injured lung epithelium and may link extracellular proteolytic activity to cell junction disassembly and intracellular signaling.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute Lung Injury / chemically induced
  • Acute Lung Injury / metabolism
  • Adherens Junctions / metabolism*
  • Animals
  • Bleomycin
  • Cell Line, Tumor
  • Epithelial Cells / enzymology*
  • Humans
  • Matrix Metalloproteinase 7 / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Respiratory Mucosa / enzymology*
  • Signal Transduction
  • Wnt Proteins / metabolism
  • beta Catenin / metabolism*

Substances

  • Wnt Proteins
  • beta Catenin
  • Bleomycin
  • Matrix Metalloproteinase 7