Activation of P2X7 purinoceptor-stimulated TGF-beta 1 mRNA expression involves PKC/MAPK signalling pathway in a rat brain-derived type-2 astrocyte cell line, RBA-2.
The present study investigates the receptor and mechanisms involved in ATP-stimulated transforming growth factor-beta 1 (TGF-beta 1) mRNA expression of a type-2 astrocyte cell line, RBA-2. RT-PCR analysis revealed that RBA-2 type-2 astrocytes possess abundant P2X(4) and P2X(7) receptors. ATP and P2X(7) receptor-sensitive agonist, BzATP, both stimulated TGF-beta 1 mRNA expression in a time and dose-dependent manner. The stimulation required a minimum of 500 muM ATP; BzATP was much more potent that ATP, and P2X(7)-selective antagonist, oATP, inhibited the effects. In addition, ATP metabolites ADP, AMP and adenosine were ineffective in stimulation of TGF-beta 1 mRNA expression. Thus, the effect of ATP was mediated through the P2X(7) receptors. To investigate further the mechanisms by which the P2X(7) receptor mediated the TGF-beta 1 mRNA expression, the cells were treated with inhibitors for mitogen-activated kinase (MAPK) or protein kinase C (PKC), PD98059 or GF109203X, respectively. Both PD98059 and GF109203X inhibited the ATP-stimulated TGF-beta 1 mRNA expression. Furthermore, ATP and BzATP stimulated ERK1/2 activation and the activation was inhibited by PKC inhibitors, GF109203X and Gö6976. In conclusion, activation of P2X(7) receptors enhanced TGF-beta 1 mRNA expression and the effect involved PKC/MAPK signalling pathway in RBA-2 type-2 astrocytes.
Institute of Neuroscience, College of Life Science, National Yang Ming University, Brain Research Center, University System of Taiwan, Taipei, Taiwan, ROC.
Chia-Mei
CM
Wang
Yuan-Yi
YY
Chang
Synthia H
SH
Sun
D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000166:cytology; D002227:Carbazoles / Q000494:pharmacology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D020935:MAP Kinase Signaling System / Q000502:physiology; D008301:Maleimides / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000235:genetics*; D053773:Transforming Growth Factor beta1
D002227:Carbazoles; D005419:Flavonoids; D007211:Indoles; D008301:Maleimides; C548228:P2rx4 protein, rat; C546470:P2rx7 protein, rat; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C081021:Go 6976; D000249:Adenosine Monophosphate; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; C017199:2',3'-dialdehyde ATP; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D000241:Adenosine; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one