Conditional, inducible gene silencing in dopamine neurons reveals a sex-specific role for Rit2 GTPase in acute cocaine response and striatal function
Brudnick Neuropsychiatric Research Institute; Department of Neurobiology; Gene Therapy Center; Viral Vector Core; Melikian Lab; Martin Lab; Tapper Lab; Graduate School of Biomedical Sciences, Neuroscience Program
Amino Acids, Peptides, and Proteins | Behavioral Neurobiology | Enzymes and Coenzymes | Nervous System | Neuroscience and Neurobiology | Pharmacology | Substance Abuse and Addiction
Dopamine (DA) signaling is critical for movement, motivation, and addictive behavior. The neuronal GTPase, Rit2, is enriched in DA neurons (DANs), binds directly to the DA transporter (DAT), and is implicated in several DA-related neuropsychiatric disorders. However, it remains unknown whether Rit2 plays a role in either DAergic signaling and/or DA-dependent behaviors. Here we leveraged the TET-OFF system to conditionally silence Rit2 in Pitx3(IRES2-tTA) mouse DANs. Following DAergic Rit2 knockdown (Rit2-KD), mice displayed an anxiolytic phenotype, with no change in baseline locomotion. Further, males exhibited increased acute cocaine sensitivity, whereas DAergic Rit2-KD suppressed acute cocaine sensitivity in females. DAergic Rit2-KD did not affect presynaptic TH and DAT protein levels in females, nor was TH was affected in males; however, DAT was significantly diminished in males. Paradoxically, despite decreased DAT levels in males, striatal DA uptake was enhanced, but was not due to enhanced DAT surface expression in either dorsal or ventral striatum. Finally, patch recordings in nucleus accumbens (NAcc) medium spiny neurons (MSNs) revealed reciprocal changes in spontaneous EPSP (sEPSP) frequency in male and female D1+ and D2+ MSNs following DAergic Rit2-KD. In males, sEPSP frequency was decreased in D1+, but not D2+, MSNs, whereas in females sEPSP frequency decreased in D2+, but not D1+, MSNs. Moreover, DAergic Rit2-KD abolished the ability of cocaine to reduce sEPSP frequency in D1+, but not D2+, male MSNs. Taken together, our studies are among the first to acheive AAV-mediated, conditional and inducible DAergic knockdown in vivo. Importantly, our results provide the first evidence that DAergic Rit2 expression differentially impacts striatal function and DA-dependent behaviors in males and females.
Addiction, Anxiety, Excitability, Gene delivery, Transporters in the nervous system
DOI of Published Version
Neuropsychopharmacology. 2019 Jul 5. doi: 10.1038/s41386-019-0457-x. [Epub ahead of print] Link to article on publisher's site
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
Sweeney, Carolyn G.; Kearney, Patrick J.; Fagan, Rita R.; Smith, Lindsey A.; Bolden, Nicholas C.; Zhao-Shea, Rubing; Rivera, Iris V.; Kolpakova, Jenya; Xie, Jun; Gao, Guangping; Tapper, Andrew R.; Martin, Gilles E.; and Melikian, Haley, "Conditional, inducible gene silencing in dopamine neurons reveals a sex-specific role for Rit2 GTPase in acute cocaine response and striatal function" (2019). Neurobiology Publications and Presentations. 247.