Osteocyte Mechanobiology

Abstract

Purpose of review: Over the past decades, osteocytes have emerged as mechano-sensors of bone and master regulators of bone homeostasis. This article summarizes latest research and progress made in understanding osteocyte mechanobiology and critically reviews tools currently available to study these cells.

Recent findings: Whereas increased mechanical forces promote bone formation, decrease loading is always associated with bone loss and skeletal fragility. Recent studies identified cilia, integrins, calcium channels, and G-protein coupled receptors as important sensors of mechanical forces and Ca²⁺ and cAMP signaling as key effectors. Among transcripts regulated by mechanical forces, sclerostin and RANKL have emerged as potential therapeutic targets for disuse-induced bone loss. In this paper, we review the mechanisms by which osteocytes perceive and transduce mechanical cues and the models available to study mechano-transduction. Future directions of the field are also discussed.

Keywords: Bone homeostasis; Mechanical forces; Osteocyte; Sclerostin.

Figure 1

Osteocyte (white stellate cell), sense mechanical forces through cellular sensors (integrins, cilium, calcium channels and GPCR) and then transform these biomechanical stimuli into biological responses that results in the secretion of several factors capable of affecting effector cells such as osteoblasts (dark blue), bone lining cells (light blue) and osteoclasts (pink). Osteocytes, osteoblast and bone lining cells express PTHRs (black) and LRP5/4 (blue) which are involved in mechanobiology