Defactinib attenuates osteoarthritis by inhibiting positive feedback loop between H-type vessels and MSCs in subchondral bone

Yanjun Hu; Hangtian Wu; Ting Xu; Yutian Wang; Hanjun Qin; Zilong Yao; Peisheng Chen; Yongheng Xie; Zhiguo Ji; Kaifan Yang; Yu Chai; Xianrong Zhang; Bin Yu; Zhuang Cui

doi:10.1016/j.jot.2020.04.008

Defactinib attenuates osteoarthritis by inhibiting positive feedback loop between H-type vessels and MSCs in subchondral bone

J Orthop Translat. 2020 May 19:24:12-22. doi: 10.1016/j.jot.2020.04.008. eCollection 2020 Sep.

Authors

Yanjun Hu^{1

2}, Hangtian Wu^{1

2}, Ting Xu³, Yutian Wang^{1

2}, Hanjun Qin^{1

2}, Zilong Yao^{1

2}, Peisheng Chen^{1

4}, Yongheng Xie^{1

2}, Zhiguo Ji^{1

2}, Kaifan Yang^{1

2}, Yu Chai^{1

5}, Xianrong Zhang^{1

2}, Bin Yu^{1

2}, Zhuang Cui^{1

2}

Affiliations

¹ Department of Orthopedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China.
² Key Laboratory of Bone and Cartilage Regeneration Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China.
³ Department of Sleep Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China.
⁴ Department of Orthopedics, Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou, Fujian 350007, China.
⁵ Department of Orthopedic Surgery, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.

Abstract

Background: Abnormal bone formation in subchondral bone resulting from uncoupled bone remodeling is considered a central feature in osteoarthritis (OA) pathogenesis. H-type vessels can couple angiogenesis and osteogenesis. We previously revealed that elevated H-type vessels in subchondral bone were correlated with OA and focal adhesion kinase (FAK) in MSCs is critical for H-type vessel formation in osteoporosis. The aim of this study was to explore the correlation between H-type vessels and MSCs in OA pathogenesis through regulation of H-type vessel formation using defactinib (an FAK inhibitor).

Methods: In vivo: 3-month-old male C57BL/6J (WT) mice were randomly divided into three groups: sham controls, vehicle-treated ACLT mice, and defactinib-treated ACLT mice (25 mg/kg, intraperitoneally weekly). In vitro: we explored the role of conditioned medium (CM) of MSCs from subchondral bone of different groups on the angiogenesis of endothelial cells (ECs). Flow cytometry, Western blotting, ELISA, real time (RT)-PCR, immunostaining, CT-based microangiography, and bone micro-CT (μCT) were used to detect changes in relative cells and tissues.

Results: This study demonstrated that inhibition of H-type vessels with defactinib alleviated OA by inhibiting H-type vessel-linked MSCs in subchondral bone. During OA pathogenesis, H-type vessels and MSCs formed a positive feedback loop contributing to abnormal bone formation in subchondral bone. Elevated H-type vessels provided indispensable MSCs for abnormal bone formation in subchondral bone. Flow cytometry and immunostaining results confirmed that the amount of MSCs in subchondral bone was obviously higher in vehicle-treated ACLT mice than that in sham controls and defactinib-treated ACLT mice. In vitro, p-FAK in MSCs from subchondral bone of vehicle-treated ALCT mice increased significantly relative to other groups. Further, the CM from MSCs of vehicle-treated ACLT mice enhanced angiogenesis of ECs through FAK-Grb2-MAPK-linked VEGF expression.

Conclusions: Our results demonstrate that defactinib inhibits OA by suppressing the positive feedback loop between H-type vessels and MSCs in subchondral bone.

The translational potential of this article: Our results provide a mechanistic rationale for the use of defactinib as an effective candidate for OA treatment.

Keywords: Defactinib; FAK; H-type vessels; MSCs; Osteoarthritis; Subchondral bone.