Behavioral and cognitive data in mice with different tryptophan-metabolizing enzymes knocked out

This article demonstrates behavioral changes in mice in response to free adaptation and drinking session adaptation modules implemented in their social home environment, the IntelliCage. These data complement the study “Deletion of TDO2, IDO-1 and IDO-2 differentially affects mouse behavior and cognitive function” (Too LK, Li KM, Suarna C, Maghzal GJ, Stocker R, McGregor IS, et al., 2016) [1]. Prior to programmed drinking sessions, all mice were exposed to a home cage adaptation module during which there was no time limit on water access – the free adaptation module. The exploratory behaviors are here expressed as percentages of visits with nosepokes and of visits with licks. The measurements by percentage of exploratory activity showed minimal genotype effects. The number of nosepokes or licks per corner visit also was compared between WT and gene knockout (GKO) IDO1 mice, WT and GKO IDO2 mice and WT and GKO TDO2 mice and demonstrated unremarkable behavioral changes during the free adaptation module. Analysis of drinking session adaptation behavior showed no genotype effect between WT and GKO of IDO1, IDO2 or TDO2 background. Notwithstanding the absence of genotype differences, each IDO1, IDO2 or TDO2 animal group displayed a specific pattern of adaptation to the drinking session modules. Furthermore, IDO1 GKO mice showed a more rapid recovery of lick frequency to the baseline level compared to the WT equivalents in a simple patrolling task during the first complete testing cycle (R1). TDO2 GKO mice on the other hand did not differ from their WT equivalents in terms of lick frequency over the three test days of complex patrolling and discrimination reversal tasks. Lastly, IDO2 GKO mice reduced their visits to the permanently non-rewarding reference corners by the same degree as did the WT mice.

showed no genotype effect between WT and GKO of IDO1, IDO2 or TDO2 background. Notwithstanding the absence of genotype differences, each IDO1, IDO2 or TDO2 animal group displayed a specific pattern of adaptation to the drinking session modules. Furthermore, IDO1 GKO mice showed a more rapid recovery of lick frequency to the baseline level compared to the WT equivalents in a simple patrolling task during the first complete testing cycle (R1). TDO2 GKO mice on the other hand did not differ from their WT equivalents in terms of lick frequency over the three test days of complex patrolling and discrimination reversal tasks. Lastly, IDO2 GKO mice reduced their visits to the permanently non-rewarding reference corners by the same degree as did the WT mice.
& 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Psychology More specific subject area Genetic engineering to eliminate one of the three tryptophan-metabolizing enzymes -IDO1, IDO2 and TDO2in mice.

Experimental features
Behavioral analysis of mice subjected to adaptation and learning modules in the IntelliCage Data source location The University of Sydney, New South Wales, Australia Data accessibility Data are with this article

Value of the data
The experimental approach and data allow comparative evaluation of baseline nosepoking and licking behaviors as percentages of total corner visit frequency, and nosepoke or lick frequency in every visit, of mice with or without a functional IDO1, IDO2 or TDO2 gene.
The data are valuable for understanding behavioral adaptation to the introduction of fixed drinking sessions (i.e. availability of water as a reward) by mice deficient in the IDO1, IDO2 or TDO2 genes.
The data make clear that the genetic background of different mice may influence adaptative behavior to the drinking sessions more than the gene modifications tested, emphasizing that studies with GKO mice must employ WT mice of the identical strain.
It is shown that mice deficient in IDO1, IDO2 or TDO2 enzymes exhibit different cognitive changes compared to their WT equivalents, which is relevant to understanding the role of the kynurenine pathway of tryptophan metabolism in behavioral adaptation.

Data
The current data show distinct behaviors of WT and GKO mice deficient in the IDO1 (Figs. 1, 4 and 7), IDO2 (Figs. 2, 5 and 8) or TDO2 (Figs. 3, 6 and 9) genes when they were subjected to a drinking  Mouse group % Visit with nosepoke(s) Fig. 2. IDO2 deficiency is associated with minimal change in exploratory activity by percentage of total visit frequency after 5 h of free adaptation during the dark phase of R1. Percent visits with nosepokes after 5 h of exploration in the light phase during R1 (a) and R2 (b) were not significantly different between WT and GKO mice. There was also no significant genotype effect on percent visits with licks after 5 h of exploration in light phase during R1 (c) and R2 (d). Deficiency of IDO2 resulted in a significant increase in percent visits with nosepokes after 5 h of nocturnal exploration in R1 (e), but not in R2 (f). A significant genotype effect was however not observed in both R1 (g) and R2 (h) in terms of percent visits with licks during the dark phase (d, h). Data are mean 7SEM. **p o0.01, unpaired t-test with Welch's correction in the event of unequal variances. Total n ¼16 mice per WT or GKO group. session test module in the IntelliCage system. In addition, the lick frequency of mice when subjected to cognitive tests was compared between the WT and GKO of IDO1 mice (Fig. 10) as well as between the WT and GKO of TDO2 (Fig. 11) mice to evaluate the reward-driven behavior that was potentially associated with the altered cognitive performance. Moreover, the percentage of reference visits made by WT and GKO IDO2 mice in simple patrolling was compared (Fig. 12), to provide additional data to support the observed genotype effect on this parameter in the complex patrolling task (see Fig. 5 7. Corner visit frequency of IDO1 WT and GKO mice during drinking and non-drinking sessions in R1 and R2. In comparison to the day before drinking sessions were executed ("baseline"), in both R1 (a) and R2 (b) the IDO1 WT and GKO mice maintained the same level of corner visit frequency throughout the drinking sessions. However, they significantly increased their corner visits during non-drinking sessions on the first day, then decreased them on the next day, in R1 (c) and R2 (d), implying that they had become aware that water rewards were not available in some sessions. The visit frequency of test day 1 or 2 was compared to that on the previous day by repeated contrast. The data (mean 7 SEM) showed no significant genotype effect at each level of repeated contrast. *po 0.05, **p o 0.01, ***po 0.001, repeated contrast. Total n ¼16 mice per WT or GKO group.

Experimental design, materials and methods
The data involve the same set of animals and methods as described [1]. Mice were initially trained with the free adaptation and nosepoke adaptation modules prior to the drinking session adaptation. The three adaptation modules and the cognitive function test modules have been described in detail previously [1].

Acknowledgments
This study was supported by a grant to NHH and ISM by Australian National Health and Medical Research Council. LKT was sponsored by a Scholarship provided by the Ministry of Science, Technology and Innovation (MOSTI), Malaysia. RS received support from an Australian National Health and Medical Research Council Fellowship. The authors thank A.L. Mellor and H. Funakoshi for providing IDO1 GKO mice and TDO2 heterozygous mice, respectively.

Transparency document. Supplementary material
Transparency data associated with this article can be found in the online version at http://dx.doi. org/10.1016/j.dib.2016.08.071.