
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.08.30.610534
preprint
1
Article
Validation studies and multi-omics analysis of Zhx2 as a candidate quantitative trait gene underlying brain oxycodone metabolite (oxymorphone) levels and behavior
Lynch William B.
Miracle Sophia A.
Goldstein Stanley I.
Beierle Jacob A. http://orcid.org/0000-0001-6517-7614

Bhandari Rhea
Gerhardt Ethan T.
Farnan Ava
Nguyen Binh-Minh
Wingfield Kelly K. http://orcid.org/0000-0002-9387-9063

Kazerani Ida
Saavedra Gabriel A.
Averin Olga
Baskin Britahny M.
Ferris Martin T.
Reilly Christopher A.
Emili Andrew
Bryant Camron D.
01 9 2024
2024.08.30.610534https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.08.30.610534
nihpp-2024.08.30.610534.pdf
ABSTRACT

Sensitivity to the subjective reinforcing properties of opioids has a genetic component and can predict addiction liability of opioid compounds. We previously identified Zhx2 as a candidate gene underlying increased brain concentration of the oxycodone ( OXY ) metabolite oxymorphone ( OMOR ) in BALB/cJ ( J ) versus BALB/cByJ ( By ) females that could increase OXY state-dependent reward. A large structural intronic variant is associated with a robust reduction of Zhx2 expression in J mice, which we hypothesized enhances OMOR levels and OXY addiction-like behaviors. We tested this hypothesis by restoring the Zhx2 loss-of-function in Js ( MVKO ) and modeling the loss-of-function variant through knocking out the Zhx2 coding exon ( E3KO ) in Bys and assessing brain OXY metabolite levels and behavior. Consistent with our hypothesis, Zhx2 E3KO females showed an increase in brain OMOR levels and OXY-induced locomotor activity. However, contrary to our hypothesis, state-dependent expression of OXY-CPP was decreased in E3KO females and increased in E3KO males. We also overexpressed Zhx2 in the livers and brains of Js and observed Zhx2 overexpression in select brain regions that was associated with reduced OXY state-dependent learning. Integrative transcriptomic and proteomic analysis of E3KO mice identified astrocyte function, cell adhesion, extracellular matrix properties, and endothelial cell functions as pathways influencing brain OXY metabolite concentration and behavior. These results support Zhx2 as a quantitative trait gene underlying brain OMOR concentration that is associated with changes in OXY behavior and implicate potential quantitative trait mechanisms that together inform our overall understanding of Zhx2 in brain function.
==== Body
pmc
