[Transforming growth factor-beta1 stimulates matrix metalloproteinase-9 production through ERK activation pathway and upregulation of Ets-1 protein].
OBJECTIVE
To investigate the molecular mechanism of transforming growth factor-beta1 (TGF-beta1) in regulating the production of matrix metalloproteinase-9 (MMP-9) protein.


METHODS
Mouse immortal podocyte cells were cultured. Different concentrations (1, 2, and 5 ng/l) of TGF-beta1 were added into the culture medium. Cell culture without TGF-beta1 stimulation was used as control group. The activity of MMP-9 in the supernatant of the culture medion was assayed by gelatin zymography, expression of MMP-9 mRNA was assessed by RT-PCR; the activation of ERK pathway and the level of a transcriptional factor Ets-1 protein was analyzed by Western blotting. PD98059, a specific inhibitor of ERK1/2 activation, was added into the culture fluid of the podocytes for 30 minutes, than 2 ng/ml TGF-beta1 was added. The above mentioned tested were conducted to observe the influence of the inhibitor of ERK1/2 activation.


RESULTS
The MMP-9 activity was very week in the supernatant of culture fluid of the control group and was increased in the TGF-beta1 groups dose-dependently. After the podocytes were co-incubated with 1 ng/ml TGF-beta1 for 24 hours, the MMP-9 activity was 26.86 times that of the control group (P < 0.01). Since the 12th hour after co-incubation with 2 ng/ml TGF-beta1 the MMP-9 activity in the supernatant of culture fluid began to be significantly increased and remained at high level till the 48 th hour. RT-PCR showed that low-level MMP-9 mRNA expression in the control group. After stimulation of 2 ng/ml TGF-beta1 for 6 hours the MMP-9 mRNA expression was 2.71 times that of the control group (P < 0.01) and the high-level expression lasted 24 hours. Western blotting showed low-level Ets-1 protein in the control group. At the time point of 12 th hour after stimulation of TGF-beta1 the Ets-1 protein expression was increased in all the three TGF-beta1 groups. After stimulation with 2 ng/ml TGF-beta1 for 4 hours the Ets-1 protein expression was 2.71 times that of the control group (P <0.01). After pretreatment of the podocyte with PD98059 for 30 minutes, the added 2 ng/ml TGF-beta1 failed to increase the MMP-9 activity and up-regulate the MMP-9 mRNA expression.


CONCLUSIONS
TGF-beta1 stimulates the production of MMP-9 by activation of cytoplasmic ERK signaling pathway and upregulation of Ets-1 expression.
Huang
Hai-Chang
HC
Division of Nephrology, Peking University First Hospital & Institute of Nephrology, Beijing 100034, China.
Liu
Sen-Yan
SY
Liang
Yan
Y
Liu
Ying
Y
Li
Jing-Zi
JZ
Wang
Hai-Yan
HY
D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000096:biosynthesis*; D007678:Kidney Glomerulus / Q000166:cytology*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D050784:Proto-Oncogene Protein c-ets-1 / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
C494041:ETS1 protein, human; D050784:Proto-Oncogene Protein c-ets-1; D012333:RNA, Messenger; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D048049:Extracellular Signal-Regulated MAP Kinases; D020780:Matrix Metalloproteinase 9