Transforming growth factor beta (TGFbeta) mediates Schwann cell death in vitro and in vivo: examination of c-Jun activation, interactions with survival signals, and the relationship of TGFbeta-mediated death to Schwann cell differentiation.
In some situations, cell death in the nervous system is controlled by an interplay between survival factors and negative survival signals that actively induce apoptosis. The present work indicates that the survival of Schwann cells is regulated by such a dual mechanism involving the negative survival signal transforming growth factor beta (TGFbeta), a family of growth factors that is present in the Schwann cells themselves. We analyze the interactions between this putative autocrine death signal and previously defined paracrine and autocrine survival signals and show that expression of a dominant negative c-Jun inhibits TGFbeta-induced apoptosis. This and other findings pinpoint activation of c-Jun as a key downstream event in TGFbeta-induced Schwann cell death. The ability of TGFbeta to kill Schwann cells, like normal Schwann cell death in vivo, is under a strong developmental regulation, and we show that the decreasing ability of TGFbeta to kill older cells is attributable to a decreasing ability of TGFbeta to phosphorylate c-Jun in more differentiated cells.
Parkinson
D B
DB
Department of Anatomy, University College London, London WC1E 6BT, United Kingdom.
Dong
Z
Z
Bunting
H
H
Whitfield
J
J
Meier
C
C
Marie
H
H
Mirsky
R
R
Jessen
K R
KR
D000818:Animals; D000831:Animals, Newborn; D019138:Antibodies, Blocking / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D019898:Autocrine Communication / Q000502:physiology; D019771:Axotomy; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D018507:Gene Expression Regulation, Developmental; D048031:JNK Mitogen-Activated Protein Kinases; D007797:Laminin / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020890:Neuregulin-1 / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017978:Receptors, Growth Factor / Q000235:genetics / Q000378:metabolism; D012583:Schwann Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012584:Sciatic Nerve / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
D019138:Antibodies, Blocking; D007797:Laminin; D020890:Neuregulin-1; D010455:Peptides; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D016212:Transforming Growth Factor beta; C117467:neuregulin beta; C008973:polyornithine; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases