title: Adrenomedullin induces matrix metalloproteinase-2 activity in rat aortic adventitial fibroblasts.
abstract: BACKGROUND
  The delicate balance of the extracellular matrix (ECM) determines the stiffness of the vascular wall, and adventitial fibroblasts are involved in ECM formation by synthesizing and degrading matrix proteins. In the present study, we examined the effect of the bioactive peptide adrenomedullin (AM) on activity and expression of matrix metalloproteinases (MMPs) in cultured aortic adventitial fibroblasts.
  
  
  RESULTS
  In cultured adventitial fibroblasts isolated from aorta of adult Wistar rats, 10(-6)mol/L angiotensin II (Ang II) significantly (p<0.05) down-regulated MMP-2 activity as determined by in vitro gelatin zymography. In contrast, 10(-7)mol/L synthetic rat AM significantly (p<0.05) stimulated zymographic MMP-2 activity by 23%, increasing intracellular cAMP, and AM abolished the action of Ang II, augmenting the MMP-2 activity. Similarly, Ang II down-regulated MMP-2 protein expression assessed by Western blotting, whereas AM increased it. Furthermore, 8-bromo-cAMP, an analogue of cAMP, mimicked the effect of AM, and H-89, an inhibitor for protein kinase A (PKA), significantly decreased the basal and AM-induced MMP-2 activity.
  
  
  CONCLUSIONS
  This study provides a new insight into the biological action of AM and its intracellular signaling system of cAMP/PKA stimulating the matrix degrading enzyme MMP-2, suggesting an important role for this molecule in modulating ECM deposition in the adventitial layer.
authors.affiliation: First Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Japan. ttsuruda@med.miyazaki-u.ac.jp
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tsuruda
authors.forename: Johji
authors.initials: J
authors.lastname: Kato
authors.forename: Yuan-Ning
authors.initials: YN
authors.lastname: Cao
authors.forename: Kinta
authors.initials: K
authors.lastname: Hatakeyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Masuyama
authors.forename: Takuroh
authors.initials: T
authors.lastname: Imamura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kitamura
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Asada
authors.forename: Tanenao
authors.initials: T
authors.lastname: Eto
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D053607:Adrenomedullin; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000033:anatomy & histology*; D002478:Cells, Cultured; D003238:Connective Tissue / Q000033:anatomy & histology* / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004789:Enzyme Activation; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology; D014665:Vasodilator Agents / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D007546:Isoquinolines; D010455:Peptides; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; D014665:Vasodilator Agents; D000804:Angiotensin II; D053607:Adrenomedullin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000242:Cyclic AMP; D020778:Matrix Metalloproteinase 2; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide