AAV capsids target muscle-resident cells with different efficiencies-A comparative study between AAV8, AAVMYO, and AAVMYO2

Timothy J McGowan; Nicolas Lewerenz; Eleonora Maino; Marco Thürkauf; Lena Jörin; Markus A Rüegg

doi:10.1016/j.omtm.2025.101451

AAV capsids target muscle-resident cells with different efficiencies-A comparative study between AAV8, AAVMYO, and AAVMYO2

Mol Ther Methods Clin Dev. 2025 Mar 14;33(2):101451. doi: 10.1016/j.omtm.2025.101451. eCollection 2025 Jun 12.

Authors

Timothy J McGowan¹, Nicolas Lewerenz¹, Eleonora Maino¹, Marco Thürkauf¹, Lena Jörin¹, Markus A Rüegg¹

Affiliation

¹ Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.

Abstract

Adeno-associated viruses (AAVs) of different serotypes are commonly used in gene therapies and gene interrogation studies to deliver transgenes to skeletal muscle in humans and mice. While efficient muscle fiber transduction is possible, little is known of their capacity to transduce muscle-residing mononuclear cells. Here, we addressed this question for AAV8 and the two myotropic AAVs, AAVMYO and AAVMYO2, by engineering them to express the tdTomato gene. AAVs were then injected intramuscularly or intravenously at two different doses into adult mice followed by flow-cytometry-based isolation of endothelial cells, immune cells, muscle stem cells, and fibro-adipogenic progenitor cells from the tibialis anterior muscle. Overall, we noted varying rates of tdTomato expression across all cell types. Transduction efficiency fluctuated in AAV serotype-dependent, titer-dependent, administration-dependent, and cell-dependent manners. By visualizing AAV DNA in vivo, we confirmed that AAV8, AAVMYO, and AAVMYO2 deliver transgenes to muscle-residing mononuclear cells. We show that mononuclear cells are also successfully transduced in the dy ^W /dy ^W mouse model of LAMA2-related muscular dystrophy. Altogether, we demonstrate that muscle-residing mononuclear cells are transduced by AAVs and provide an insightful guidance for researchers aiming to target muscle-resident mononuclear cells in their studies.

Keywords: AAV; AAV8; AAVMYO; AAVMYO2; endothelial cells; fibro-adipogenic progenitor cells; gene therapy; immune cells; muscle stem cells; skeletal muscle.