Casein kinase 2 activity is a host restriction factor for AAV transduction.

Overview

So far, the mechanisms that impede AAV transduction, especially in the human heart, are poorly understood, hampering the introduction of new, effective gene therapy strategies. Therefore, the aim of this study was to identify and overcome the main cellular barriers to successful transduction in the heart, using iPSC-derived cardiomyocytes (iPSC-CMs), cardiac fibroblasts (iPSC-CFs), and primary endothelial cells (HAECs) to model vector-host interactions. Through phosphoproteome analysis we established that casein kinase 2 (CK2) signalling is one of the most significantly affected pathways upon AAV exposure. Transient inhibition of CK2 activity substantially enhanced the transduction rate of AAV2, AAV6 and AAV9 in all tested cell types. In particular, CK2 inhibition improved the trafficking of AAVs through the cytoplasm, impaired DNA-damage response through destabilisation of Mre11 and altered the RNA processing pathways, which were also highly responsive to AAV transduction. Also, it augmented transgene expression in already transduced iPSC-CFs, which retain AAV genomes in a functional, but probably silent form. In summary, presented study provides new insights into the current understanding of the host-AAV vector interaction, identifying CK2 activity as a key barrier to efficient transduction and transgene expression, what may translate to improvement the outcome of AAV-based therapies in the future.