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Sphingosine-1-phosphate effects on PKC isoform expression in human osteoblastic cells
J D Lampasso1, A Kamer, J Margarone
1Department of Oral Biology, University of Buffalo, NY, USA.
Prostaglandins, Leukotrienes, and Essential Fatty Acids
|December 1, 2001
Summary
Sphingosine-1-phosphate (S1P) influences human osteoblast proliferation via protein kinase C (PKC) pathways. S1P increases expression of PKC alpha and iota, suggesting their role in bone cell growth.
Area of Science:
- Biochemistry
- Cell Biology
- Orthopedics
Background:
- Sphingosine-1-phosphate (S1P) is implicated in human osteoblast proliferation.
- S1P's mitogenic effects are thought to involve Gi-linked protein receptors and protein kinase C (PKC) pathways.
Purpose of the Study:
- To investigate the role of specific PKC isoforms in osteoblastic cell proliferation.
- To determine the effect of S1P on PKC isoform expression in human osteoblasts.
Main Methods:
- Human osteoblasts were treated with S1P.
- Expression levels of PKC isoforms (alpha, delta, iota, lambda) were analyzed.
- The effect of pertussis toxin (PT) pretreatment on S1P-induced changes was assessed.
Main Results:
- PKC alpha, delta, and iota isoforms were highly expressed in human osteoblasts; PKC lambda was minimally detected.
- S1P significantly increased the expression of PKC alpha (25%) and PKC iota (30%).
- S1P did not affect PKC delta expression, and PT pretreatment inhibited S1P's effects on PKC alpha and iota.
Conclusions:
- S1P modulates human osteoblast proliferation through PKC signaling.
- PKC alpha and PKC iota are key isoforms involved in S1P-mediated osteoblast responses.
- Gi-linked protein receptors mediate S1P's influence on PKC alpha and iota expression.
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