Differential regulation of matrix metalloproteinase-9 and tissue plasminogen activator activity by the cyclic-AMP system in lipopolysaccharide-stimulated rat primary astrocytes.
We investigated the effect of the cAMP system on lipopolysaccharide (LPS)-induced changes in the activity of matrix metalloproteinases (MMPs) and tissue plasminogen activator (tPA) in rat primary astrocytes. LPS stimulation increased MMP-9 and decreased tPA activity in rat primary astrocytes. Co-treatment with a cAMP analog, dibutyryl-cAMP (db-cAMP), or the cAMP elevating beta-adrenergic agonist, isoproterenol, concentration-dependently inhibited LPS-induced MMP-9 activity. In contrast, db-cAMP concentration-dependently increased tPA activity in both basal and LPS-stimulated rat primary astrocytes. To confirm the effect of cAMP on MMP-9 and tPA activity, we treated LPS-stimulated astrocytes with cAMP phosphodiesterase inhibitors, IBMX or rolipram, and they exhibited similar effects to db-cAMP, namely decreasing MMP-9 activity and increasing tPA activity. RT-PCR analysis of MMP-9 mRNA expression and MMP-9 promoter luciferase reporter assays revealed transcriptional upregulation by LPS stimulation and downregulation by db-cAMP. In contrast, the level of tPA mRNA expression was increased both by LPS and by cAMP treatment. Consistent with RT-PCR analysis, tPA promoter reporter assays showed increased activity by both LPS and cAMP stimulation. Interestingly, the level of mRNA encoding plasminogen activator inhibitor-1 (PAI-1) was increased by LPS stimulation and decreased back to control level after co-treatment with db-cAMP, suggesting that PAI-1 expression plays a major role in the regulation of tPA activity. To examine PKA involvement in the effects of db-cAMP on MMP-9 and tPA activity, we added the PKA inhibitors, H89 or rp-cAMP, along with db-cAMP, and they inhibited db-cAMP-mediated changes in tPA activity without affecting MMP-9 activity. These data suggest that cAMP differentially modulates MMP-9 and tPA activity through a mechanism related to PKA activation. The differential regulation of MMP-9 and tPA by the cAMP system may confer more sophisticated regulation of physiological processes, such as extracellular matrix remodeling and cell migration, by activated astrocytes.
Lee
Soon Young
SY
Department of Pharmacology, School of Medicine and Center for Geriatric Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 143-701, South Korea.
Kim
Hee Jin
HJ
Lee
Woo Jong
WJ
Joo
So Hyun
SH
Jeon
Se-Jin
SJ
Kim
Ji Woon
JW
Kim
Hee Sun
HS
Han
Seol-Heui
SH
Lee
Jongmin
J
Park
Seung Hwa
SH
Cheong
Jae Hoon
JH
Kim
Won-Ki
WK
Ko
Kwang Ho
KH
Shin
Chan Young
CY
D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D001483:Base Sequence; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D017931:DNA Primers; D004789:Enzyme Activation; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012323:RNA Processing, Post-Transcriptional; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D010959:Tissue Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D008070:Lipopolysaccharides; D000242:Cyclic AMP; D010959:Tissue Plasminogen Activator; D020780:Matrix Metalloproteinase 9