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Ascorbic acid decreases neutral endopeptidase activity in cultured osteoblastic cells
Christoph Schmid1, Claudia Ghirlanda-Keller, Martina Gosteli-Peter
1Division of Endocrinology and Diabetes, Department of Internal Medicine, University Hospital of Zurich, 8091 Zurich, Switzerland. christoph.schmid@usz.ch
Regulatory Peptides
|May 24, 2005
Summary
Ascorbic acid (ASA) reduces neprilysin (NEP) activity and protein levels in osteoblast cells. This finding is crucial for understanding NEP
Area of Science:
- Biochemistry
- Cell Biology
- Bone Biology
Background:
- Neprilysin (NEP) is a peptidase found in various tissues, including bone.
- Its role in osteoblast lineage cell growth is not well understood.
- Decreased NEP activity is linked to cancer cell growth.
Purpose of the Study:
- To investigate the activity of NEP in osteoblastic cells.
- To determine the effect of ascorbic acid (ASA) on NEP activity and protein levels.
- To explore the relationship between NEP activity and osteoblast growth.
Main Methods:
- Assessed NEP activity in PyMS osteoblastic cells using a specific cleavage assay.
- Utilized thiorphan to block NEP activity.
- Measured thymidine incorporation to assess DNA synthesis.
- Quantified NEP protein levels via Western blot analysis.
Main Results:
- Ascorbic acid (ASA) decreased NEP activity and protein in a dose-dependent manner.
- ASA potentiated IGF-I's stimulatory effect on DNA synthesis, an effect attenuated by echistatin.
- Growth-regulating agents like calcium and dexamethasone did not affect NEP activity.
Conclusions:
- Ascorbic acid (ASA) downregulates neprilysin (NEP) activity and protein in osteoblastic cells.
- ASA influences integrin signaling and peptide processing, impacting cell growth.
- NEP activity may play a role in osteoblast lineage cell proliferation.