Transforming growth factor-beta1 enhances expression of brain-derived neurotrophic factor and its receptor, TrkB, in neurons cultured from rat cerebral cortex.
The effects of transforming growth factor (TGF)-beta1 on expression of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, TrkB, in neurons cultured from the cerebral cortex of 18-day-old embryonic rats were examined. BDNF mRNA was significantly increased from 24-48 hr after the TGF-beta1 treatment over 20 ng/ml. Accumulation of BDNF protein in the culture medium was also potentiated by TGF-beta1, although the intracellular content of BDNF was nearly unchanged. The enhancement of BDNF mRNA expression was suppressed by the co-presence of decorin, a small TGF-beta-binding proteoglycan that inhibits the biological activities of TGF-betas. mRNA expression of full-length TrkB, the bioactive high-affinity receptor for BDNF, was also upregulated after treatment with TGF-beta1. These observations suggest that: 1) TGF-beta1 potentiates BDNF/TrkB autocrine or local paracrine system; and 2) the neurotrophic activity of TGF-beta1 is partly responsible for the BDNF induced by TGF-beta1 itself. To test this latter possibility, we examined the neuronal survival activity of TGF-beta1 with or without K252a, a selective inhibitor of Trk family tyrosine kinases. TGF-beta1 significantly enhanced neuronal survival, but the co-presence of K252a completely suppressed the activity, demonstrating the involvement of Trk receptor signaling in TGF-beta1-mediated neuronal survival in cultured rat cortical neurons. These results seem to be in line with recent findings by other investigators that some neurotrophic factors including BDNF require TGF-betas as a cofactor to exert their neurotrophic activities.
Sometani
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A
Laboratory of Molecular Biology, Gifu Pharmaceutical University, Gifu, Japan.
Kataoka
H
H
Nitta
A
A
Fukumitsu
H
H
Nomoto
H
H
Furukawa
S
S
D000818:Animals; D019898:Autocrine Communication / Q000187:drug effects / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002227:Carbazoles / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D058575:Decorin; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016326:Extracellular Matrix Proteins; D005260:Female; D005333:Fetus; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D026121:Indole Alkaloids; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D011509:Proteoglycans / Q000378:metabolism / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020813:Receptor, trkB / Q000235:genetics*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
D019208:Brain-Derived Neurotrophic Factor; D002227:Carbazoles; C546880:Dcn protein, rat; D058575:Decorin; D004791:Enzyme Inhibitors; D016326:Extracellular Matrix Proteins; D026121:Indole Alkaloids; D011509:Proteoglycans; D012333:RNA, Messenger; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C049985:staurosporine aglycone; D020813:Receptor, trkB