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Neuraminidase‐mediated desialylation augments AAV9‐mediated gene expression in skeletal muscle
Author(s) -
Zhu Hongling,
Wang Tao,
John Lye Robert,
French Brent A.,
Annex Brian H.
Publication year - 2018
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.3049
Subject(s) - luciferase , neuraminidase , histamine , biology , gene expression , genetic enhancement , microbiology and biotechnology , pharmacology , immunology , gene , biochemistry , transfection , virus
Abstract Background Following systemic delivery, AAV9‐mediated gene expression is significantly increased in ischemic versus non‐ischemic muscle, suggesting that AAV9 is an attractive vector for treating peripheral arterial disease. Potential mechanisms underlying ischemia‐augmented expression include: (i) increased vascular permeability and (ii) “unmasking” of endogenous AAV9 receptors. In the present study, we aimed to reconstitute the ischemic induction of AAV9 in vivo, using local injection of histamine (to increase vascular permeability) and neuraminidase (to desialylate cell surface glycans). Methods Bioassays were performed to optimize the effects of histamine and neuraminidase after intramuscular injection. Histamine and/or neuraminidase were then injected intramuscularly shortly before intravenous injection of an AAV9 vector expressing luciferase. Luciferase expression was serially assessed with bioluminescence imaging. At the end of the study, tissues were harvested for assays of luciferase activity and AAV9 genome copy number aiming to assess AAV‐mediated gene expression and transduction, respectively. Results Intramuscular injection of either neuraminidase or neuraminidase plus histamine significantly increased both transduction and gene expression, whereas histamine alone had little effect. Pre‐injection with neuraminidase increased AAV9‐mediated gene delivery by four‐ to nine‐fold and luciferase activity by 60–100‐fold. Luciferase activity in neuraminidase‐injected muscle was > 100‐fold higher than in any off‐target tissue (including heart, liver and brain). Conclusions The ischemic induction of AAV9‐mediated gene expression in muscle can largely be reconstituted by pre‐injecting neuraminidase intranmuscularly. This strategy may prove useful in future human gene therapy protocols as a quick and efficient means to selectively target systemically injected AAV9 to localized regions of muscle, thus decreasing the potential for adverse effects in off‐target tissues.