Laminin-6 assembles into multimolecular fibrillar complexes with perlecan and participates in mechanical-signal transduction via a dystroglycan-dependent, integrin-independent mechanism

Jonathan C.R. Jones*, Kimberly Lane, Susan B. Hopkinson, Emilia Lecuona, Robert C. Geiger, David A. Dean, Eduardo Correa-Meyer, Meredith Gonzales, Kevin Campbell, Jacob I. Sznajder, Scott Budinger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Mechanical ventilation is a valuable treatment regimen for respiratory failure. However, mechanical ventilation (especially with high tidal volumes) is implicated in the initiation and/or exacerbation of lung injury. Hence, it is important to understand how the cells that line the inner surface of the lung [alveolar epithelial cells (AECs)] sense cyclic stretching. Here, we tested the hypothesis that matrix molecules, via their interaction with surface receptors, transduce mechanical signals in AECs. We first determined that rat AECs secrete an extracellular matrix (ECM) rich in anastamosing fibers composed of the α3 laminin subunit, complexed with β1 and γ1 laminin subunits (i.e. laminin-6), and perlecan by a combination of immunofluorescence microscopy and immunoblotting analyses. The fibrous network exhibits isotropic expansion when exposed to cyclic stretching (30 cycles per minute, 10% strain). Moreover, this same stretching regimen activates mitogen-activated-protein kinase (MAPK) in AECs. Stretch-induced MAPK activation is not inhibited in AECs treated with antagonists to α3 or β1 integrin. However, MAPK activation is significantly reduced in cells treated with function-inhibiting antibodies against the α3 laminin subunit and dystroglycan, and when dystroglycan is knocked down in AECs using short hairpin RNA. In summary, our results support a novel mechanism by which laminin-6, via interaction with dystroglycan, transduces a mechanical signal initiated by stretching that subsequently activates the MAPK pathway in rat AECs. These results are the first to indicate a function for laminin-6. They also provide novel insight into the role of the pericellular environment in dictating the response of epithelial cells to mechanical stimulation and have broad implications for the pathophysiology of lung injury.

Original languageEnglish (US)
Pages (from-to)2557-2566
Number of pages10
JournalJournal of cell science
Volume118
Issue number12
DOIs
StatePublished - Jun 15 2005

Keywords

  • Matrix adhesion
  • Matrix receptors
  • Stretching

ASJC Scopus subject areas

  • Cell Biology

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