Rapid TGF beta 1 effects on actin cytoskeleton of astrocytes: comparison with other factors and implications for cell motility.
We have previously shown that long-term treatment of primary cultured astrocytes with TGF beta 1 induces morphological changes accompanied by increases in actin and GFAP synthesis, and a profound rearrangement of the cytoskeleton. The present report describes the short-term reorganization of actin filaments induced by TGF beta 1 in rat cerebellum cultured astrocytes and in an astrocytic cell line. TGF beta 1 caused the appearance of new actin and vinculin organizations, without protein synthesis. This cytoskeletal rearrangement was followed by altered cell-cell interactions. All these changes induced by TGF beta 1 were different and slower than those induced by serum, PDGF, and endothelin. TGF beta 1 induced the appearance of lamellipodia, organelles found at the cell front of motile cells in low-density cultures of immortalized astrocytes. These results indicate that the changes in the astrocyte cytoskeleton induced by TGF beta 1 are probably associated with cell movement. The events promoted by TGF beta 1 might help to clarify its action in the brain during embryogenesis and in tissue repair.
Gagelin
C
C
Unité de Recherche sur la Glande Thyroide et la Régulation Hormonale, U.96 INSERM, Kremlin Bicêtre, France.
Pierre
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M
Gavaret
J M
JM
Toru-Delbauffe
D
D
D000199:Actins / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D016232:Endothelins / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D007700:Kinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014746:Vimentin
D000199:Actins; D016232:Endothelins; D016212:Transforming Growth Factor beta; D014746:Vimentin