PGAM5 knockout causes depressive-like behaviors in mice via ATP deficiency in the prefrontal cortex

Major depressive disorder (MDD) affects about 17% population in the world. Although abnormal energy metabolism plays an important role in the pathophysiology of MDD, however, how deficiency of adenosine triphosphate (ATP) products affects emotional circuit and what regulates ATP synthesis are still need to be elaborated.

Our study aimed to investigate how deficiency of PGAM5-mediated depressive behavior.

We firstly discovered that PGAM5 knockout (PGAM5^-/- ) mice generated depressive-like behaviors. The phenotype was reinforced by the observation that chronic unexpected mild stress (CUMS)-induced depressive mice exhibited lowered expression of PGAM5 in prefrontal cortex (PFC), hippocampus (HIP), and striatum. Next, we found, with the using of functional magnetic resonance imaging (fMRI), that the functional connectivity between PFC reward system and the PFC volume were reduced in PGAM5^-/- mice. PGAM5 ablation resulted in the loss of dendritic spines and lowered density of PSD95 in PFC, but not in HIP. Finally, we found that PGAM5 ablation led to lowered ATP concentration in PFC, but not in HIP. Coimmunoprecipitation study showed that PGAM5 directly interacted with the ATP F₁ F₀ synthase without influencing the interaction between ATP F₁ F₀ synthase and Bcl-xl. We then conducted ATP administration to PGAM5^-/- mice and found that ATP could rescue the behavioral and neuronal phenotypes of PGAM5^-/- mice.

Our findings provide convincing evidence that PGAM5 ablation generates depressive-like behaviors via restricting neuronal ATP production so as to impair the number of neuronal spines in PFC.