Journal of Histochemistry and Cytochemistry, Vol. 47, 1646c-1647, December 1999, Copyright © 1999, The Histochemical Society, Inc.


PROCEEDINGS

18 Dynamic gene expression of proprotein convertases (PCs) and their putative substrate precursor proteins in rat aorta organ culture

P. Stawowya,c, J. Marcinkiewicza, K. Grafc, M. Cheretiena,b, E. Fleckc, and M. Marcinkiewicza
a Lab. of Molecular Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Canada, H2W 1R7,
b Loeb Health Research Institute, Ottawa, Canada, K1Y 4K9,
c Medicine/Cardiology, Charit, Humboldt-University Berlin and German Heart Institute Berlin, 13353 Berlin, Germany,

The involvement of growth factors (GFs) in arterial pathology (e.g. atherosclerosis) is well established. Most of these proteins require posttranslational processing by proprotein convertases (PCs), which can potentially control their activation. These enzymes include members of the family of subtilisin/kexin-like mammalian PCs with specificity to Arg, as well as the novel enzyme SKI-1 with specificity to Leu and Thr at the cleavage site. We investigated the gene expression of PCs in rat aorta, using an organ culture system (serum-free DEMEM; 0, 4 and 24h), which maintains cell-cell/cell-matrix interactions. Induction of cell proliferation and organ viability was assessed by PCNA immunoblotting, demonstrating the increase over time. Furthermore, PCNA immunostaining was localized to vascular smooth muscle cells (VSMCs) of aorta cultured for 24h. As demonstrated by western blot analysis, PC5 isoform A and PC7 were present in tissue extracts, whereas shed PC5 isoform B was detected at 4 h (peak) and 24 h in culture medium (CM). PC7 was not found in CM. SKI-1 was found only after 24 h in tissue extracts and CM. Furin was detected at all time points and could not be found in CM. Other convertases, such as PC1 and PC2 were undetectable. Injury related GFs, like NGF, PDGF-A and TGF-beta 1 were released into CM and found in tissue extracts. Immunohistochemical detection of PCs was generally weak in normal arteries, mainly localizing to VSMCs at the adventitial border. In the rat aorta organ culture, PCs immunoreactivity increased and was found thoughout the medial layer in VSMCs, colocalized with proliferating VSMCs. In conclusion, this is the first report, demonstrating that several PCs are present in arteries and that their gene expression displays a dynamic course with the induction of VSMCs and their potential substrates (injury related GFs). Furthermore, we demonstrated that the rat aorta organ culture is a good model for the study of vascular pathologies.





This Article
Full Text (PDF)
Alert me when this article is cited
Alert me if a correction is posted
Services
Similar articles in this journal
Similar articles in PubMed
Alert me to new issues of the journal
Download to citation manager
Google Scholar
Articles by Stawowy, P.
Articles by Marcinkiewicz, M.
Articles citing this Article
PubMed
PubMed Citation
Articles by Stawowy, P.
Articles by Marcinkiewicz, M.


Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]