SLC17A6 and major depressive disorder: To assess the role of neuronal glutamine transporters in depression, either SNAT-1 or SNAT-2 was selectively knocked out (SNAT-1 cKO and SNAT-2 cKO) in glutamatergic neurons by injecting pAAV2.pX552ch-sgSlc38a1 or pAAV2.pX552ch-sgSlc38a2 into Vglut2-IRES-Cre::CRISPR/CAS9-EGFP mice, respectively (Fig. 2A, M).