Investigating the Movement Patterns of Mice with Skin-Specific Piezo2 Excision

• Hunter Huang, Neuroscience, University of Delaware

• Joshua Neunuebel, Department of Psychological and Brain Sciences, University of Delaware

Gentle touch shapes animal social behaviors and relies on Piezo2, a mechanosensitive ion channel in the skin. Somatosensation functions in stress regulation, affection, dominance behaviors, and exploration. In mice, both social and non-social behaviors can be characterized through movement patterns and interactions with social partners or environmental features. To investigate the role of touch in movement patterns in a social setting, we used the Cre-LoxP system to generate mice with Piezo2 excised from the skin. To investigate whether the resulting touch deficit alters movement dynamics in a social setting, we recorded continuous video data as mixed-sex groups (2 males and 2 females per group) of adult (8 -12 weeks old) Piezo2 knockout mice (cKO; n = 3 groups) or floxed controls (FX; n = 3 groups) interacted for 5 hours. We characterized movement patterns by examining periods of social interaction, locomotion patterns, and time in close proximity to arena walls. To observe the impact of a touch deficit on social dynamics, we employed a program that classifies social interactions (SIs) as periods of overlap between ellipses fit to each mouse. Preliminary data indicate that, while FX and cKO mice show similar SI mean and total durations, FX male-female pairs engage in a significantly higher number of SIs than cKOs (Wilcoxon rank-sum test, p < 0.0001). Quantification of mouse positions in each frame indicated that cKO mice travel significantly less distance than FX mice (p < 0.01). To characterize time spent in close proximity to walls, we combined trajectory plots across all recordings to define wall and non-wall zones. While total time spent in close proximity to walls was comparable between genotypes, cKOs performed fewer wall visits than FX mice (p < 0.001). Our data suggest that skin Piezo2 excision impacts mouse movement patterns in a social setting.