Sensory nerves regulate mesenchymal stromal cell lineage commitment by tuning sympathetic tones
Bo Hu1,2, Xiao Lv1,3, Hao Chen1
1Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, Maryland, USA.
The Journal of Clinical Investigation
|March 20, 2020
Summary
Sensory nerves regulate bone mass by releasing prostaglandin E2 (PGE2), which activates EP4 receptors. This pathway inhibits fat cell formation and promotes bone growth in adult mice.
Area of Science:
- Bone biology
- Neuroendocrinology
- Stem cell differentiation
Background:
- Sensory nerves are newly recognized regulators of bone mass accrual.
- Prostaglandin E2 (PGE2) from osteoblasts activates sensory nerve EP4 receptors, promoting bone formation via sympathetic inhibition.
- Osteoblasts, the bone-forming cells, originate from mesenchymal stromal/stem cells (MSCs).
Purpose of the Study:
- To investigate the role of the PGE2/EP4 sensory nerve axis in regulating mesenchymal stromal/stem cell (MSC) differentiation in adult mice.
- To determine the impact of sensory denervation, EP4 receptor, and COX-2 on osteogenesis and adipogenesis.
- To explore therapeutic strategies for modulating bone formation and fat differentiation.
Main Methods:
- Sensory denervation in adult mice.
- Genetic knockout of EP4 receptor in sensory nerves and COX-2 in osteoblasts.
- Administration of SW033291 (PGE2 enhancer) and propranolol (beta blocker).
- Assessment of osteogenesis and adipogenesis in bone marrow.
Main Results:
- Sensory denervation, EP4 receptor knockout, or COX-2 knockout significantly promoted adipogenesis and inhibited osteogenesis.
- SW033291 and propranolol administration increased osteogenesis and decreased adipogenesis.
- The osteogenic effect of SW033291 was abolished in EP4-knockout mice, unlike propranolol's effect.
Conclusions:
- The prostaglandin E2 (PGE2)/EP4 sensory nerve signaling pathway is a key regulator of mesenchymal stromal/stem cell (MSC) differentiation in adult bone marrow.
- Targeting the PGE2/EP4 axis offers a potential therapeutic strategy for bone diseases.
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