AAV-based gene editing of type 1 collagen mutation to treat osteogenesis imperfecta

Yeon-Suk Yang; Tadatoshi Sato; Sachin Chaugule; Hong Ma; Jun Xie; Guangping Gao; Jae-Hyuck Shim

doi:10.1016/j.omtn.2023.102111

AAV-based gene editing of type 1 collagen mutation to treat osteogenesis imperfecta

Mol Ther Nucleic Acids. 2023 Dec 26;35(1):102111. doi: 10.1016/j.omtn.2023.102111. eCollection 2024 Mar 12.

Authors

Yeon-Suk Yang¹, Tadatoshi Sato^{1

2

3

4}, Sachin Chaugule¹, Hong Ma^{2

5

6}, Jun Xie^{2

5

6}, Guangping Gao^{2

5

6

3}, Jae-Hyuck Shim^{1

2

3}

Affiliations

¹ Department of Medicine, Division of Rheumatology, UMass Chan Medical School, Worcester, MA 01655, USA.
² Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA 01655, USA.
³ Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA 01655, USA.
⁴ Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
⁵ Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA 01655, USA.
⁶ Viral Vector Core, UMass Chan Medical School, Worcester, MA 01655, USA.

Abstract

Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility, low bone mass, fractures, and extraskeletal manifestations. Since OI is commonly caused by single-nucleotide mutation(s) in the COL1A1 or COL1A2 genes encoding type I collagens, we developed a genome-editing strategy to correct a Col1a2 mutation in an OIM mouse model resembling a severe dominant form of human type III OI. Using a recombinant adeno-associated virus (rAAV), we delivered CRISPR-Cas9 to bone-forming osteoblast-lineage cells in the skeleton. Homology-directed repair (HDR)-mediated gene editing efficiency in these cells was improved when CRISPR-Cas9 was coupled with a donor AAV vector containing a promoterless partial mouse Col1a2 complementary DNA sequence. This approach effectively reversed the dysregulation of osteogenic differentiation by a Col1a2 mutation in vitro. Furthermore, systemic administration of dual rAAVs in OIM mice lowered bone matrix turnover rates by reducing osteoblast and osteoclast development while improving the cellular network of mechano-sensing osteocytes embedded in the bone matrix. This strategy significantly improved bone architecture/mass/mineralization, skeletal deformities, grip strength, and spontaneous fractures. Our study is the first demonstration that HDR-mediated gene editing via AAV-mediated delivery effectively corrects a collagen mutation in OI osteoblasts and reverses skeletal phenotypes in OIM mice.

Keywords: AAV; CRISPR-Cas9; GeneRide; MT: RNA/DNA Editing; bone; osteoblasts; osteogenesis imperfecta; type 1 collagen.

Abstract

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