Role of fibronectin in the inhibitory effect of TGF-beta on choline acetyltransferase activity in co-cultures of spinal cord neurons and myotubes.
We have recently shown that the enhanced expression of choline acetyltransferase (ChAT) activity in co-cultures of spinal cord motoneurons and muscle cells was blocked by transforming growth factor-beta (TGF-beta) (Dev. Brain Res., 57, 129-137, 1990). This study was performed to investigate the role of fibronectin in this effect. TGF-beta increased fibronectin level about 2-fold in extracellular matrix of spinal cord cells and skeletal myotubes in culture. Addition of a synthetic polypeptide that competitively inhibits fibronectin binding to its cell surface receptor recovered the TGF-beta-induced suppression of ChAT activity in co-cultures. The polypeptide did not affect ChAT activity in cultures of spinal cord cells alone or in co-cultures without TGF-beta. These results indicate that TGF-beta inhibits the stimulation of ChAT activity in spinal cord neurons in co-culture through a change in the composition and/or amount of fibronectin in the extracellular matrix at neuromuscular contacts.
Kengaku
M
M
Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neurosciences, Japan.
Kawata
A
A
Kawashima
S
S
Nakane
M
M
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D005260:Female; D005353:Fibronectins / Q000502:physiology*; D051379:Mice; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009132:Muscles / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D011247:Pregnancy; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D005353:Fibronectins; D016212:Transforming Growth Factor beta; D002795:Choline O-Acetyltransferase