Bone-Targeting AAV-Mediated Gene Silencing in Osteoclasts for Osteoporosis Therapy

Yeon-Suk Yang; Jun Xie; Sachin Chaugule; Dan Wang; Jung-Min Kim; JiHea Kim; Phillip W L Tai; Seok-Kyo Seo; Ellen Gravallese; Guangping Gao; Jae-Hyuck Shim

doi:10.1016/j.omtm.2020.04.010

Bone-Targeting AAV-Mediated Gene Silencing in Osteoclasts for Osteoporosis Therapy

Mol Ther Methods Clin Dev. 2020 Apr 18:17:922-935. doi: 10.1016/j.omtm.2020.04.010. eCollection 2020 Jun 12.

Authors

Yeon-Suk Yang¹, Jun Xie^{2

3

4}, Sachin Chaugule¹, Dan Wang^{2

3}, Jung-Min Kim¹, JiHea Kim¹, Phillip W L Tai^{2

3}, Seok-Kyo Seo⁵, Ellen Gravallese⁶, Guangping Gao^{2

3

4

7}, Jae-Hyuck Shim^{1

7}

Affiliations

¹ Division of Rheumatology, University of Massachusetts Medical School, Worcester, MA, USA.
² Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
³ Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
⁴ Viral Vector Core, University of Massachusetts Medical School, Worcester, MA, USA.
⁵ Department of Obstetrics and Gynecology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
⁶ Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
⁷ Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.

Abstract

Improper activity of bone-resorbing osteoclasts results in low bone density and deterioration of bone structure, which increase the risk of fractures. Anti-resorptive therapies targeting osteoclasts have proven effective in preserving bone mass, but these therapeutic agents lead to defective new bone formation and numerous potential side effects. In this study, we demonstrate that recombinant adeno-associated virus, serotype 9 (rAAV9) can deliver to osteoclasts an artificial microRNA (amiR) that silences expression of key osteoclast regulators, RANK (receptor activator for nuclear factor κB) and cathepsin K (rAAV9.amiR-rank, rAAV9.amiR-ctsk), to prevent bone loss in osteoporosis. As rAAV9 is highly effective for the transduction of osteoclasts, systemic administration of rAAV9 carrying amiR-rank or amiR-ctsk results in a significant increase of bone mass in mice. Furthermore, the bone-targeting peptide motif (Asp)₁₄ or (AspSerSer)₆ was grafted onto the AAV9-VP2 capsid protein, resulting in significant reduction of transgene expression in non-bone peripheral organs. Finally, systemic delivery of bone-targeting rAAV9.amiR-ctsk counteracts bone loss and improves bone mechanical properties in mouse models of postmenopausal and senile osteoporosis. Collectively, inhibition of osteoclast-mediated bone resorption via bone-targeting rAAV9-mediated silencing of ctsk is a promising gene therapy that can preserve bone formation and mitigate osteoporosis, while limiting adverse off-target effects.

Keywords: artificial miRNA; bone formation; bone resorption; cathepsin k; osteoblast; osteoclast; osteoclastogenesis; osteoporosis; rAAV; rank.

Abstract

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