Abstract | OBJECTIVE: METHODS: Smooth muscle cells (SMCs) were isolated from aortas of OPN knock-out (OPN-/-) and wild type (OPN+/+) mice. RESULTS: OPN-/- SMCs were identical to OPN+/+ SMCs in morphology and stained positively for SM lineage proteins, desmin, smooth muscle alpha-actin and SM22alpha. No spontaneous calcification was observed in OPN-/- SMCs under normal culture conditions or in medium containing 1%, 3%, or 5% fetal bovine serum. However, when cultured in medium containing elevated concentrations of inorganic phosphate, an inducer of vascular calcification, a significantly higher calcification was observed in OPN-/- SMCs compared to OPN+/+ SMCs that, in response to elevated phosphate, synthesized and secreted OPN into the culture. Finally, retroviral transduction of mouse OPN cDNA into OPN-/- SMCs rescued the calcification phenotype of the cells. CONCLUSION: These results are the first to demonstrate an inhibitory role of endogenously produced OPN on SMC calcification, suggesting a novel feedback mechanism where OPN produced locally by the SMCs may serve as an important inducible inhibitor of vascular calcification.
|
Authors | Mei Y Speer, Yung-Ching Chien, Mary Quan, Hsueh-Ying Yang, Hojatollah Vali, Marc D McKee, Cecilia M Giachelli |
Journal | Cardiovascular research
(Cardiovasc Res)
Vol. 66
Issue 2
Pg. 324-33
(May 01 2005)
ISSN: 0008-6363 [Print] England |
PMID | 15820201
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
|
Chemical References |
- DNA, Complementary
- Phosphates
- SPP1 protein, human
- Sialoglycoproteins
- Spp1 protein, mouse
- Osteopontin
|
Topics |
- Animals
- Aorta
- Calcinosis
(etiology, metabolism)
- Cell Culture Techniques
- DNA, Complementary
(administration & dosage)
- Disease Susceptibility
- Genetic Vectors
(administration & dosage)
- Mice
- Mice, Knockout
- Muscle, Smooth, Vascular
(metabolism)
- Osteopontin
- Phosphates
(pharmacology)
- Retroviridae
(genetics)
- Sialoglycoproteins
(deficiency, genetics)
- Transduction, Genetic
(methods)
|