Two engineered AAV capsid variants for efficient transduction of human cortical neurons directly converted from iPSC

Recombinant adeno-associated virus (AAV) is the most widely used vector for gene therapy in clinical trials. To increase transduction efficiency and specificity, novel engineered AAV variants with modified capsid sequences are evaluated in human cell cultures and non-human primates. In the present study, we tested two novel AAV capsid variants, AAV2-NNPTPSR and AAV9-NVVRSSS, in human cortical neurons, which were directly converted from human induced pluripotent stem cells and cocultured with rat primary astrocytes. AAV2-NNPTPSR variant efficiently transduced both induced human cortical glutamatergic neurons and induced human cortical GABAergic interneurons. By contrast, AAV9-NVVRSSS variant transduced both induced human cortical neurons and cocultured rat primary astrocytes. High viral titers (1x10E5 viral genomes per cell) caused a significant decrease in viability of induced human cortical neurons. Low viral titers (1x10E4 viral genomes per cell) lead to a significant increase in the neuronal activity marker c-Fos in transduced human neurons following treatment with a potassium channel blocker, which may indicate functional alterations induced by viral transduction and/or transgene expression.