title: Differential regulation of matrix metalloproteinase-9 and tissue plasminogen activator activity by the cyclic-AMP system in lipopolysaccharide-stimulated rat primary astrocytes.
abstract: 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.
authors.affiliation: 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.
authors.forename: Soon Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Woo Jong
authors.initials: WJ
authors.lastname: Lee
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Joo
authors.forename: Se-Jin
authors.initials: SJ
authors.lastname: Jeon
authors.forename: Ji Woon
authors.initials: JW
authors.lastname: Kim
authors.forename: Hee Sun
authors.initials: HS
authors.lastname: Kim
authors.forename: Seol-Heui
authors.initials: SH
authors.lastname: Han
authors.forename: Jongmin
authors.initials: J
authors.lastname: Lee
authors.forename: Seung Hwa
authors.initials: SH
authors.lastname: Park
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Cheong
authors.forename: Won-Ki
authors.initials: WK
authors.lastname: Kim
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Ko
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Shin
mesh_terms: 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*
chemical_list: D017931:DNA Primers; D008070:Lipopolysaccharides; D000242:Cyclic AMP; D010959:Tissue Plasminogen Activator; D020780:Matrix Metalloproteinase 9