BK ablation attenuates osteoblast bone formation via integrin pathway

• Published in: Cell death & disease 2019-09, Vol.10 (10), p.738-14, Article 738
• Main Authors: Wang, Yinhang, Guo, Qiang, Hei, Hongya, Tao, Jie, Zhou, Yi, Dong, Jibin, Xin, Hong, Cai, Hui, Gao, Jianjun, Yu, Ker, Reilly, Svetlana, Yin, Peihao, Zhang, Xuemei
• Format: Article
• Language: English
• Subjects: 13/1; 13/109; 14/34; 14/63; 38/109; 631/443/63; 631/443/811; 64/60; 96/1; Animals; Antibodies; Biochemistry; Biomedical and Life Sciences; Bone growth; Bone marrow; Bone mass; Bone mineral density; Bone strength; Calcium channels; Calcium conductance; Cancellous bone; Cell Biology; Cell Culture; Cell Differentiation - genetics; Extracellular matrix; Focal Adhesion Kinase 1 - genetics; Immunology; Integrins - genetics; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits - genetics; Life Sciences; Lumbar Vertebrae - growth & development; Lumbar Vertebrae - pathology; MAP Kinase Signaling System - genetics; Mesenchymal Stem Cells - cytology; Mesenchymal Stem Cells - metabolism; Mesenchyme; Mice, Knockout; Osteoblastogenesis; Osteoblasts; Osteoblasts - metabolism; Osteoblasts - pathology; Osteogenesis; Osteogenesis - genetics; Osteoporosis; Osteoporosis - genetics; Osteoporosis - physiopathology; Potassium channels; Potassium Channels, Calcium-Activated - genetics; Potassium conductance; Signal transduction; Stem cell transplantation; Stem cells; Vertebrae; Vitamin D
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-019-1972-8

Impaired bone formation is one of the major causes of low bone mass and skeletal fragility that occurs in osteoporosis. However, the mechanisms underlying the defects in bone formation are not well understood. Here, we report that big conductance calcium-activated potassium channels (BKs) are required for bone formation and osteoblast function both in vivo and in vitro. By 15 weeks of age, BK knockout (BKO) mice exhibited a decline in bone mineral density and trabecular bone volume of the tibiae and lumbar vertebrae, which were associated with impaired bone formation and osteoblast activity. Mechanistically, BK ablation in bone and bone marrow mesenchymal stem cells (BMSCs) of BKO mice inhibited integrin signaling. Furthermore, the binding of α subunit of BK with integrin β1 protein in osteoblasts was confirmed, and FAK-ERK1/2 signaling was proved to be involved by genetic modification of KCNMA1 (which encodes the α subunit of BK) in ROS17/2.8 osteoblast cells. These findings indicated that BK regulates bone formation by promoting osteoblast differentiation via integrin pathway, which provided novel insight into ion transporter crosstalk with the extracellular matrix in osteoblast regulation and revealed a new potential strategy for intervention in correcting bone formation defects.