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Stimulation of Notch Signaling in Mouse Osteoclast Precursors
Published on: February 28, 2017
p85alpha regulates osteoblast differentiation by cross-talking with the MAPK pathway
Xiaohua Wu1, Shi Chen, Selina A Orlando
1Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
The Journal of Biological Chemistry
|February 18, 2011
Summary
The p85α subunit of phosphoinositide 3-kinase (PI3K) is crucial for mesenchymal stem cell (MSC) osteoblast differentiation. Its absence impairs differentiation by increasing MAPK pathway activation, hindering bone formation.
Area of Science:
- Cellular Biology
- Stem Cell Research
- Molecular Signaling
Background:
- Class IA phosphoinositide 3-kinase (PI3K) regulates critical cellular functions.
- The p85 regulatory subunit is a key component of the PI3K pathway.
- Mesenchymal stem cells (MSCs) differentiate into osteoblasts, adipocytes, and chondrocytes.
Purpose of the Study:
- To investigate the role of the p85α subunit of PI3K in regulating MSC biological functions.
- To determine the impact of p85α deficiency on osteoblast differentiation from MSCs.
Main Methods:
- Comparison of wild-type (WT) and p85α-deficient (p85α(-/-)) bone marrow-derived MSCs.
- Assays included CFU-F, thymidine incorporation, β-galactosidase staining, ALP activity, and osteocalcin mRNA expression.
- Analysis of cell cycle regulators, Akt, MAPK pathways, and response to BMP2, LY294002, and PD98059.
Main Results:
- p85α deficiency in MSCs increased cell growth, proliferation, and cell cycle progression, while reducing senescence.
- Osteoblast differentiation was impaired in p85α(-/-) MSCs, evidenced by reduced ALP activity and osteocalcin expression.
- p85α deficiency led to increased Akt and MAPK activation; MAPK inhibition enhanced osteoblast differentiation in both genotypes.
Conclusions:
- The p85α subunit of PI3K is essential for normal osteoblast differentiation from MSCs.
- p85α deficiency impairs osteogenesis by derepressing MAPK pathway activation.
- Targeting the MAPK pathway may offer therapeutic strategies for bone regeneration.
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