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Cell elongation induces laminin alpha2 chain expression in mouse embryonic mesenchymal cells: role in visceral myogenesis.

Relan NK, Yang Y, Beqaj S, Miner JH, Schuger L - J. Cell Biol. (1999)

Bottom Line: In comparison, the expression of LM beta1 and gamma1 remains unchanged.These deficiencies were completely corrected by exogenous LM-2.The intestine, however, showed compensatory hyperplasia, perhaps related to its higher contractile activity.

View Article: PubMed Central - PubMed

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

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) alpha2 chain not present in round mesenchymal cells. LM alpha2 expression is reversible and switched on and off by altering the cell's shape in culture. In comparison, the expression of LM beta1 and gamma1 remains unchanged. Functional studies showed that mesenchymal cell spreading and further differentiation into SM are inhibited by an antibody against LM alpha2. Dy/dy mice express very low levels of LM alpha2 and exhibit congenital muscular dystrophy. Lung SM cells isolated from adult dy/dy mice spread defectively and synthesized less SM alpha-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 alpha2 chain in SM myogenesis and showed that its decrease in dy/dy mice results in abnormal SM.

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Related in: MedlinePlus

Switching cells from culture conditions promoting rounding or elongation. Mesenchymal cells cultured on poly-l-lysine (R) or with poly-l-lysine added to the culture medium after cell spreading is completed (E). After 24 h the cells were replated and cultured for an additional 24 h under similar or opposite conditions. Then immunoblotting was performed using a polyclonal antibody to LM-1/LM-2. LM α2 band appears in elongated cells (second and third lane) and is absent in the round cells (fourth and fifth lane). The first lane is LM-1 from EHS tumor, used as control.
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Figure 4: Switching cells from culture conditions promoting rounding or elongation. Mesenchymal cells cultured on poly-l-lysine (R) or with poly-l-lysine added to the culture medium after cell spreading is completed (E). After 24 h the cells were replated and cultured for an additional 24 h under similar or opposite conditions. Then immunoblotting was performed using a polyclonal antibody to LM-1/LM-2. LM α2 band appears in elongated cells (second and third lane) and is absent in the round cells (fourth and fifth lane). The first lane is LM-1 from EHS tumor, used as control.

Mentions: LM α2 chain expression is turned on and off by changes in cell shape. Switching cells from culture conditions that promote cell rounding to culture conditions that promote cell elongation and vice versa demonstrated that synthesis of LM α2 chain can be switched on and off by changes in cell shape (Fig. 4). Replating efficiency was similar for round and elongated cells (48 ± 12 and 50 ± 10% of replated cells attached, respectively).


Cell elongation induces laminin alpha2 chain expression in mouse embryonic mesenchymal cells: role in visceral myogenesis.

Relan NK, Yang Y, Beqaj S, Miner JH, Schuger L - J. Cell Biol. (1999)

Switching cells from culture conditions promoting rounding or elongation. Mesenchymal cells cultured on poly-l-lysine (R) or with poly-l-lysine added to the culture medium after cell spreading is completed (E). After 24 h the cells were replated and cultured for an additional 24 h under similar or opposite conditions. Then immunoblotting was performed using a polyclonal antibody to LM-1/LM-2. LM α2 band appears in elongated cells (second and third lane) and is absent in the round cells (fourth and fifth lane). The first lane is LM-1 from EHS tumor, used as control.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2168094&req=5

Figure 4: Switching cells from culture conditions promoting rounding or elongation. Mesenchymal cells cultured on poly-l-lysine (R) or with poly-l-lysine added to the culture medium after cell spreading is completed (E). After 24 h the cells were replated and cultured for an additional 24 h under similar or opposite conditions. Then immunoblotting was performed using a polyclonal antibody to LM-1/LM-2. LM α2 band appears in elongated cells (second and third lane) and is absent in the round cells (fourth and fifth lane). The first lane is LM-1 from EHS tumor, used as control.
Mentions: LM α2 chain expression is turned on and off by changes in cell shape. Switching cells from culture conditions that promote cell rounding to culture conditions that promote cell elongation and vice versa demonstrated that synthesis of LM α2 chain can be switched on and off by changes in cell shape (Fig. 4). Replating efficiency was similar for round and elongated cells (48 ± 12 and 50 ± 10% of replated cells attached, respectively).

Bottom Line: In comparison, the expression of LM beta1 and gamma1 remains unchanged.These deficiencies were completely corrected by exogenous LM-2.The intestine, however, showed compensatory hyperplasia, perhaps related to its higher contractile activity.

View Article: PubMed Central - PubMed

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

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) alpha2 chain not present in round mesenchymal cells. LM alpha2 expression is reversible and switched on and off by altering the cell's shape in culture. In comparison, the expression of LM beta1 and gamma1 remains unchanged. Functional studies showed that mesenchymal cell spreading and further differentiation into SM are inhibited by an antibody against LM alpha2. Dy/dy mice express very low levels of LM alpha2 and exhibit congenital muscular dystrophy. Lung SM cells isolated from adult dy/dy mice spread defectively and synthesized less SM alpha-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 alpha2 chain in SM myogenesis and showed that its decrease in dy/dy mice results in abnormal SM.

Show MeSH
Related in: MedlinePlus