The myosin and RhoGAP MYO9B influences osteocyte dendrite growth and responses to mechanical stimuli

• DOI: 10.3389/fbioe.2023.1243303
• Publication Date: 2023-08-22T10:20:12Z
• Authors: Beth S. Lee; Cynthia Murray; Jie Liu; Minji Kim; Min Sik Hwang; Tina Yueh; Myrna Mansour; Sana Qamar; Gunjan Agarwal; Do-Gyoon Kim
• Keywords: Osteocyte; Mechanotransduction

Introduction: Myosin IXB (MYO9B) is an unconventional myosin with RhoGAP activity and thus a regulator of actin cytoskeletal organization. MYO9B was previously shown to be necessary for skeletal growth health play role in actin-based functions both osteoblasts osteoclasts. However, its responses mechanical stimulation bone cells has not yet been described. Therefore, experiments were undertaken determine the cell stress vitro vivo . Methods: expression knocked down osteoblast osteocyte lines using RNA interference resulting subjected stresses including cyclic tensile strain, fluid shear stress, plating on different substrates (no substrate vs. monomeric or polymerized collagen type I). Osteocytic also regulation through Slit-Robo signaling. Further, wild-type Myo9b −/− mice regimen whole-body vibration (WBV) changes quality assessed by micro-CT. Results: Unlike control cells, MYO9B-deficient osteoblastic uniaxial strain unable orient their fibers perpendicular strain. which exhibited elongated dendrites but respond normally treatments that increase dendrite length such as stimuli found dependent polymerization state I substrates. Wild-type responded WBV increased tissue mineral density values while loss. Discussion: These results demonstrate plays key stress-induced