Adrenomedullin induces matrix metalloproteinase-2 activity in rat aortic adventitial fibroblasts.
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.
Tsuruda
Toshihiro
T
First Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Japan. ttsuruda@med.miyazaki-u.ac.jp
Kato
Johji
J
Cao
Yuan-Ning
YN
Hatakeyama
Kinta
K
Masuyama
Hiroyuki
H
Imamura
Takuroh
T
Kitamura
Kazuo
K
Asada
Yujiro
Y
Eto
Tanenao
T
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*
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