Summary
Osteocytes are the most numerous cell in bone tissue, which act as mechanosensors and coordinate adaptive
bone remodeling. Current model systems have been unable to unify the mechanisms by which osteocytes to
sense mechanical stimuli, transmit signals across an extensive 3D network, and how these transient signals
drive adaptive bone remodeling by osteoblasts and osteoclasts. In this work, we will use a new bone multicellular
unit (BMU) chip that enables longitudinal visualization of mechanosensitive calcium signaling across 3D
osteocyte networks, enabling and characterization of the role of this signaling mechanism on the
mechanoadaptive response of osteoblasts and osteoclasts in normal and injured states. Using BMU-chip, this
work will test the hypothesis, ‘Discontinuity in 3D osteocyte networks alters mechanically-evoked calcium signal
propagation which in turn modulates the spatiotemporal remodeling of effector cells’ using three specific aims.
Aim 1 will define how Pulsed Unidirectional Fluid Flow Stimuli (PUFFS) modulates dynamic changes in calcium
signaling across 3D network of osteocytes. Aim 2 will determine how 3D osteocyte networks subjected to PUFFS
modulate direct and indirect signaling and osteoblastic bone formation and osteoclastic resorption activities. Aim
3 will identify how targeted disruption of 3D osteocyte networks influence calcium signaling and long-term
functional outcomes. Completion of the proposed aims will provide a comprehensive understanding of how
mechanically evoked calcium signaling across osteocyte networks modulates functional outcomes within the
BMU in normal and injured conditions. Our team, with complementary expertise in biomedical engineering, bone
cell biology, orthopedic surgery and statistical analysis is well suited to execute this project. In the future, BMU-
chips could be utilized to probe other mechanotransduction pathways, and accelerate the development and
evaluation of drugs to treat bone disease.
