In vitro and in vivo CRISPR-Cas9 screens reveal drivers of aging in neural stem cells of the brain.

Here we develop in vitro and in vivo high-throughput CRISPR-Cas9 screening platforms to systematically uncover genes whose knockout boosts NSC activation in old mice. Our genome-wide screening pipeline in primary cultures of young and old NSCs identifies over 300 gene knockouts that specifically restore old NSC activation. Interestingly, the top gene knockouts are involved in glucose import, cilium organization and ribonucleoprotein structures. To determine which gene knockouts have a rejuvenating effect for the aging brain, we establish a scalable CRISPR-Cas9 screening platform in vivo in old mice. Of the 50 gene knockouts we tested in vivo, 23 boost old NSC activation and production of new neurons in old brains. Notably, the knockout of Slc2a4, which encodes for the GLUT4 glucose transporter, is a top rejuvenating intervention for old NSCs. GLUT4 protein expression increases in the stem cell niche during aging, and we show that old NSCs indeed uptake ~2-fold more glucose than their young counterparts. Transient glucose starvation increases the ability of old NSCs to activate, which is not further improved by knockout of Slc2a4/GLUT4 Sequenced guide counts from genome wide in vitro screen and in vivo sub screens