Dissecting AAV silencing in humanized mice

PROJECT SUMMARY
The liver has emerged as a promising target for expressing therapeutic transgenes
utilizing Adeno-Associated Viral (AAV) vector-mediated delivery. Despite numerous clinical trials
and continued progress several challenges have been identified for AAV gene therapy. In this
proposal we will dissect a major clinical hurdle, e.g. AAV transgene silencing in the human liver
and molecular mechanisms underlying this phenomenon. To achieve such, we first propose to
utilize and characterize a novel humanized liver model, which will allow precise and selective
interrogation of the mechanisms underlying AAV transgene silencing in normal as well as
diseased human hepatocytes in vivo. The second aim will build on a recent observation from
our lab showing AAV transgene expression mediated by the Human Silencing Hub (HUSH)
complex. We will further dissect and gather mechanistic inside on this process using human
hepatocytes from methylmalonic acidemia (MMA) patients in vivo. Hence MMA will serve as a
proof of concept disorder for liver directed AAV gene therapy. Finally, we will explore different
vector design and pharmacological strategies to rescue AAV gene silencing.

Grant Number: 5R01DK134408-04
NIH Institute/Center: NIH
Principal Investigator: Karl-Dimiter Bissig