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Changes in gene expression and signal transduction in microgravity
1Lab of Cell Growth, Department of Veteran's Affairs Medical Center and University of California San Fransico, CA 94121, USA. milliehf@aol.com
Journal of Gravitational Physiology : a Journal of the International Society for Gravitational Physiology
|March 18, 2003
Summary
Spaceflight microgravity slows osteoblast cell cycle entry, impacting gene expression and potentially causing bone loss. This research investigates cellular responses to microgravity to understand spaceflight-induced bone loss mechanisms.
Area of Science:
- Space Biology
- Cellular Biology
- Biomedical Research
Background:
- Space flight causes physiological changes, including bone loss, with unknown cellular mechanisms.
- Previous research focused on systemic changes, not cellular responses to microgravity.
- Osteoblast cells are crucial for bone formation and remodeling.
Purpose of the Study:
- Investigate cellular and molecular responses of osteoblasts to microgravity.
- Determine the effect of microgravity on osteoblast gene expression and cell cycle activation.
- Understand the mechanisms underlying spaceflight-induced bone loss.
Main Methods:
- Cultured normal osteoblasts (MC3T3-E1) in microgravity (0-G) and 1-G conditions.
- Activated osteoblasts in a serum-deprived state during spaceflight.
- Analyzed changes in gene expression (mRNA induction) and signal transduction pathways.
Main Results:
- Significant changes in gene expression observed in 0-G samples one day post-activation.
- Reduced mRNA induction of immediate early growth genes (cox-2, c-myc, bcl2, TGF beta1, bFGF, PCNA) in microgravity.
- No significant differences in reference gene mRNA expression between 0-G and 1-G controls.
Conclusions:
- Quiescent osteoblasts exhibit delayed cell cycle entry in microgravity.
- Microgravity itself appears to be a significant factor contributing to bone loss during spaceflight.
- Basic biological responses at tissue, cellular, and molecular levels occur in microgravity, impacting bone health.