Cell elongation induces laminin α2 chain expression in mouse embryonic mesenchymal cells: Role in visceral myogenesis

Nand K. Relan, Yan Yang, Safedin Beqaj, Jeffrey H. Miner, Lucia Schuger

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

Bronchial smooth muscle (SM) mesenchymal cell precursors change their shape from round to spread/elongated while undergoing differentiation. Here we show that this change in cell shape induces the expression of laminin (LM) α2 chain not present in round mesenchymal cells. LM α2 expression is reversible and switched on and off by altering the cell's shape in culture. In comparison, the expression of LM β1 and γ1 remains unchanged. Functional studies showed that mesenchymal cell spreading and further differentiation into SM are inhibited by an antibody against LM α2. Dy/dy mice express very low levels of LM α2 and exhibit congenital muscular dystrophy. Lung SM cells isolated from adult dy/dy mice spread defectively and synthesized less SM α- actin, desmin, and SM-myosin than controls. These deficiencies were completely corrected by exogenous LM-2. On histological examination, dy/dy mouse airways and gastrointestinal tract had shorter SM cells, and lungs from dy/dy mice contained less SM-specific protein. The intestine, however, showed compensatory hyperplasia, perhaps related to its higher contractile activity. This study therefore demonstrated a novel role for the LM α2 chain in SM myogenesis and showed that its decrease in dy/dy mice results in abnormal SM.

Original languageEnglish
Pages (from-to)1341-1350
Number of pages10
JournalJournal of Cell Biology
Volume147
Issue number6
DOIs
StatePublished - Dec 13 1999

Keywords

  • Dy/dy mice
  • Laminin
  • Lung
  • Myogenesis
  • Smooth muscle

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