Mechanisms of Transforming Growth Factor-beta1 Induced Expression of Matrix Metalloproteinase-9 in Rat Brain Astrocytes-1 Cells

• Main Authors: Hsiao Fen Cheng, 鄭小芬
• Other Authors: C. M. Yang
• Format: Others
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/72436946619785230202

碩士 === 長庚大學 === 天然藥物研究所 === 96 === Transforming growth factor beta (TGF-beta) are known as multifunctional growth factors that may stimulate the synthesis and secretion of extracellular matrix, regulates the content and activity of MMPs. In the CNS, TGF-beta1 has been widely recognized as an injury-related cytokines, specially associated with the pathophysiology of neuroinflammmation responses. However, the mechanisms regulating MMP-9 expression by TGF-beta1 in rat brain astrocytes-1 (RBA-1) remain unclear. Thus, we will investigate the mechanisms underlying TGF-beta1-induced MMP-9 expression in RBA-1 cells using Zymography, Western blotting, and RT-PCR analyses. TGF-beta1 induced expression of MMP-9 mRNA and protein in a time- and concentration-dependent manner. TGF-beta1 increased expression of MMP-9 mRNA and protein, which was inhibited by inhibitors of MEK1/2 (U0126) and JNK (SP600125). Moreover TGF-beta1 also stimulated phosphorylation of p42/p44 MAPK and JNK which was attenuated by U0126 and SP600125, respectively. In addition, TGF-beta1-induced MMP-9 expression in RBA-1 cells was significantly attenuated by inhibitors of ROS (NAC、Apocynin、DPI), PI3-K/AKT (LY29402、SH-5), NF-kappaB (helenalin and Bay11-7082), and AP-1 (Curcumin and Tanshinone). Transfection with dominant negative mutants of ERK, JNK, Akt, also inhibited TGF-beta1-induced MMP-9 expression. Moreover, TGF-beta1-stimulated activation of transcription factors such as Smad and STAT3 was revealed by immnofluorescence staining that may be mediated RBA-1 cells migration. Results obtained in this study provide more understanding of the regulatory mechanisms underlying TGF-beta1-induced MMP-9 expression in RBA-1 cells. More impact information of pathophysiological processes of CNS events affected by TGF-beta1 and MMP-9 expression and cell migration will prove beneficial in the therapeutic interventions against inflammatory disease in brain.