Induction of tumor necrosis factor receptor type 2 gene expression by tumor necrosis factor-alpha in rat primary astrocytes.
Using reverse transcription-polymerase chain reaction (RT-PCR) technique, the messenger RNA (mRNA) for tumor necrosis factor receptor type 2 (TNF-R2, 75/80 kDa) was detected in rat primary astrocytes, with much lower level of expression when compared to that for tumor necrosis factor receptor type 1 (TNF-R1, 55/60 kDa). Upon exposure to TNF-alpha (100 U/ml), the TNF-R2 mRNA level was greatly enhanced at 8 h, while TNF-R1 mRNA remained unchanged even after 24 h. The induction of TNF-R2 gene expression by TNF-alpha was dose-dependent and seemed to be unique to TNF-alpha, as interleukin-6 (IL-6) had no significant effect on TNF-R2 expression. Since TNF-R2 was reported to mediate mitogenic and gene-inducing effects in many other cell types, it is likely that the reported proliferative effect of TNF-alpha on astrocytes was also mediated by this TNF receptor subtype. Upon exposure to TNF-alpha or lipopolysaccharide (LPS), the expression of TNF-alpha gene was induced, and the LPS-induced TNF-alpha seemed to selectively enhance the TNF-R2 gene expression. Collectively, our results suggest that the TNF-alpha or LPS-induced expression of both TNF-R2 and TNF-alpha may provide a positive control mechanism to further enhance the proliferative effect of TNF-alpha in astrocytes.
Lung
H L
HL
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT.
Leung
K N
KN
Stadlin
A
A
Ma
C M
CM
Tsang
D
D
D000818:Animals; D000831:Animals, Newborn; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics*; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D017931:DNA Primers / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects*; D015850:Interleukin-6 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis / Q000235:genetics*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology*
D015703:Antigens, CD; D017931:DNA Primers; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha