Transduction of Murine Alveolar Macrophages with Adeno-associated Virus 6: A promising Tool for Cell and Gene Therapy

Alveolar macrophages (AMs) are tissue resident cells of the lung with a high self-renewing capacity. Their genetic manipulation remains challenging but due to their longevity they are promising tools for gene or cell therapy. Murine AMs were isolated from C57BL/6J mice and after analysis regarding purity and gene expression profile, they were cultured and transduced with different AAV serotypes expressing green fluorescent protein (GFP). The cells were analyzed by live cell and confocal microscopy to investigate the effects of serotype, multiplicity of infection (MOI), and incubation time. The transduction of AMs with AAV6 at a MOI of 87,500 resulted in the highest transduction rate, transgene signal intensity, and expression after 6 days. Lipopolysaccharide (LPS) stimulation caused a significant and prolonged increase of GFP protein synthesis by AMs, even after the removal of the stimulus. AMs were not activated by AAV transduction. In conclusion, after ex vivo expansion and efficient transduction with AAV6, murine AMs are highly promising tools to be evaluated in cell-, and gene-therapeutic applications, especially after cellular activation by disease induced inflammatory stimuli.