Behavioral disturbances in estrogen-related receptor alpha-null mice

Abstract

Eating disorders, such as anorexia nervosa and bulimia nervosa, are common and severe mental illnesses of unknown etiology. Recently, we identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) that is associated with the development of eating disorders. However, little is known about ESRRA function in the brain. Here, we report that Esrra is expressed in the mouse brain and demonstrate that Esrra levels are regulated by energy reserves. Esrra-null female mice display a reduced operant response to a high-fat diet, compulsivity/behavioral rigidity, and social deficits. Selective Esrra knockdown in the prefrontal and orbitofrontal cortices of adult female mice recapitulates reduced operant response and increased compulsivity, respectively. These results indicate that Esrra deficiency in the mouse brain impairs behavioral responses in multiple functional domains.

Figure 1. Esrra-Null Mice Display Impaired Behavioral Responses to Calorie Restriction

(A–C) Expression of Esrra in 14-week-old C57BL6/J mice in lateral orbitofrontal, mPFC, and cingulate cortex. (D and E) 60% calorie restriction for 10 days increases Esrra expression in mouse brain. Magnification shows retrosplenial region of cingulate cortex. (F and G) Wild-type (n = 7) and Esrra-null (n = 6) littermate mice were trained to lever press for a HFD pellet on a fixed ratio and then tested for total lever presses (F) and reward earned (G) on a progressive ratio under calorie restriction and ad lib feeding conditions. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001 indicate significant differences between groups (Student’s t test). See also Figure S1.

Figure 2. Behavioral Deficits in Esrra-Null Mice

(A) Voluntary wheel-running activity for female wild-type (WT) and Esrra-null mice for 5 days (n = 3 WT, 6 Esrra null). (B) Time spent active in home cage as measured by vibration plate (n = 17 WT, 5 Esrra null). (C and D) Distance moved and time spent on the open arm of the elevated-plus-maze (n = 8 WT, 14 null). (E) Time immobile in the forced-swim test (n = 8 WT, 14 null). (F) Home-cage grooming as measured by vibration plate (n = 17 WT, 5 Esrra null). (G) Number of marbles buried within 30 min (n = 7 WT, 12 Esrra null). (H) Time spent near old target and new target in Barnes maze (n = 5 WT, 6 Esrra null). (I) Time spent with novel mouse in three-chamber test (n = 8 WT, 10 Esrra null). (J) Time spent with novel object (n = 9 WT, 11 Esrra null). (K) Percentage of victories in the social dominance test (n = 24 unique pairings). Data presented as mean ± SEM with *p < 0.05, **p < 0.01 indicating significant differences between groups (two-way ANOVA [A] or Student’s t test [B–I and K]), except for (J), which is presented as a percentage of total victories with ***p < 0.001 indicating significant differences between groups (chi-square test).

Figure 3. Knockdown of Esrra Expression by shRNA in Cortex Produces Region-Specific Behavioral Deficits

(A) Body-weight gain in female C57BL6/J mice on a HFD after AAV delivery into cingulate (n = 10 scramble and 9 shRNA-Esrra), orbitofrontal (n = 9 scramble and 10 shRNA-Esrra), or mPFC (n = 9 scramble and 11 shRNA-Esrra). (B) Intake of a HFD after Esrra knockdown in mPFC. (C) A separate cohort of mice received AAV into mPFC and was tested for total lever presses and reward earned. (D and E) Mice from (A) were tested for home-cage grooming (D) and immobility in the forced-swim test (E). Data presented as mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001 indicate significant differences between groups (ANOVA [A] or Student’s t test [B–E]). See also Figure S2.