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Laminin alpha1 chain synthesis in the mouse developing lung: requirement for epithelial-mesenchymal contact and possible role in bronchial smooth muscle development.

Schuger L, Skubitz AP, Zhang J, Sorokin L, He L - J. Cell Biol. (1997)

Bottom Line: In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin alpha1, alpha2, and beta/gamma chains.Lung explants exposed to monoclonal antibodies to laminin alpha1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle alpha actin and desmin.Taken together, our studies suggest that laminin alpha1 chain synthesis is regulated by epithelial-mesenchymal interaction and may play a role in airway smooth muscle development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.

ABSTRACT
Laminins, the main components of basement membranes, are heterotrimers consisting of alpha, beta, and gamma polypeptide chains linked together by disulfide bonds. Laminins-1 and -2 are both composed of beta1 and gamma1 chains and differ from each other on their alpha chain, which is alpha1 and alpha2 for laminin-1 and -2, respectively. The present study shows that whereas laminins-1 and -2 are synthesized in the mouse developing lung and in epithelial-mesenchymal cocultures derived from it, epithelial and mesenchymal monocultures lose their ability to synthesize the laminin alpha1 chain. Synthesis of laminin alpha1 chain however returns upon re-establishment of epithelial-mesenchymal contact. Cell-cell contact is critical, since laminin alpha1 chain is not detected in monocultures exposed to coculture-conditioned medium or in epithelial-mesenchymal cocultures in which heterotypic cell-cell contact is prevented by an interposing filter. Immunohistochemical studies on cocultures treated with brefeldin A, an inhibitor of protein secretion, indicated both epithelial and mesenchymal cells synthesize laminin alpha1 chain upon heterotypic cell- cell contact. In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin alpha1, alpha2, and beta/gamma chains. Lung explants exposed to monoclonal antibodies to laminin alpha1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle alpha actin and desmin. Taken together, our studies suggest that laminin alpha1 chain synthesis is regulated by epithelial-mesenchymal interaction and may play a role in airway smooth muscle development.

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Addition of mesenchymal cells to epithelial monocultures stimulates LM α1 chain synthesis. (M−) No mesenchymal  cells; (M+) 1:2 epithelial/mesenchymal cell ratio; (M++) 1:4 epithelial/mesenchymal cell ratio. The first lane is LM-1 from the  EHS tumor, used as control. The inset shows staining of the nitrocellulose membrane with 0.2% amido black after immunobloting to visualize the amount of protein loaded per lane.
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Figure 7: Addition of mesenchymal cells to epithelial monocultures stimulates LM α1 chain synthesis. (M−) No mesenchymal cells; (M+) 1:2 epithelial/mesenchymal cell ratio; (M++) 1:4 epithelial/mesenchymal cell ratio. The first lane is LM-1 from the EHS tumor, used as control. The inset shows staining of the nitrocellulose membrane with 0.2% amido black after immunobloting to visualize the amount of protein loaded per lane.

Mentions: LM α1 chain synthesis seems to be directly proportional to the extent of epithelial–mesenchymal contact. This was suggested by studies in which increasing numbers of mesenchymal cells were added to prestablished (24-h-old) epithelial monocultures (Fig. 7). These ratios were selected based on the normal epithelial/mesenchymal ratio in mixed lung cell populations obtained from day 15 embryonic lungs.


Laminin alpha1 chain synthesis in the mouse developing lung: requirement for epithelial-mesenchymal contact and possible role in bronchial smooth muscle development.

Schuger L, Skubitz AP, Zhang J, Sorokin L, He L - J. Cell Biol. (1997)

Addition of mesenchymal cells to epithelial monocultures stimulates LM α1 chain synthesis. (M−) No mesenchymal  cells; (M+) 1:2 epithelial/mesenchymal cell ratio; (M++) 1:4 epithelial/mesenchymal cell ratio. The first lane is LM-1 from the  EHS tumor, used as control. The inset shows staining of the nitrocellulose membrane with 0.2% amido black after immunobloting to visualize the amount of protein loaded per lane.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2139794&req=5

Figure 7: Addition of mesenchymal cells to epithelial monocultures stimulates LM α1 chain synthesis. (M−) No mesenchymal cells; (M+) 1:2 epithelial/mesenchymal cell ratio; (M++) 1:4 epithelial/mesenchymal cell ratio. The first lane is LM-1 from the EHS tumor, used as control. The inset shows staining of the nitrocellulose membrane with 0.2% amido black after immunobloting to visualize the amount of protein loaded per lane.
Mentions: LM α1 chain synthesis seems to be directly proportional to the extent of epithelial–mesenchymal contact. This was suggested by studies in which increasing numbers of mesenchymal cells were added to prestablished (24-h-old) epithelial monocultures (Fig. 7). These ratios were selected based on the normal epithelial/mesenchymal ratio in mixed lung cell populations obtained from day 15 embryonic lungs.

Bottom Line: In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin alpha1, alpha2, and beta/gamma chains.Lung explants exposed to monoclonal antibodies to laminin alpha1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle alpha actin and desmin.Taken together, our studies suggest that laminin alpha1 chain synthesis is regulated by epithelial-mesenchymal interaction and may play a role in airway smooth muscle development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.

ABSTRACT
Laminins, the main components of basement membranes, are heterotrimers consisting of alpha, beta, and gamma polypeptide chains linked together by disulfide bonds. Laminins-1 and -2 are both composed of beta1 and gamma1 chains and differ from each other on their alpha chain, which is alpha1 and alpha2 for laminin-1 and -2, respectively. The present study shows that whereas laminins-1 and -2 are synthesized in the mouse developing lung and in epithelial-mesenchymal cocultures derived from it, epithelial and mesenchymal monocultures lose their ability to synthesize the laminin alpha1 chain. Synthesis of laminin alpha1 chain however returns upon re-establishment of epithelial-mesenchymal contact. Cell-cell contact is critical, since laminin alpha1 chain is not detected in monocultures exposed to coculture-conditioned medium or in epithelial-mesenchymal cocultures in which heterotypic cell-cell contact is prevented by an interposing filter. Immunohistochemical studies on cocultures treated with brefeldin A, an inhibitor of protein secretion, indicated both epithelial and mesenchymal cells synthesize laminin alpha1 chain upon heterotypic cell- cell contact. In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin alpha1, alpha2, and beta/gamma chains. Lung explants exposed to monoclonal antibodies to laminin alpha1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle alpha actin and desmin. Taken together, our studies suggest that laminin alpha1 chain synthesis is regulated by epithelial-mesenchymal interaction and may play a role in airway smooth muscle development.

Show MeSH
Related in: MedlinePlus