Downregulation of Npas4 in parvalbumin interneurons and cognitive deficits after neonatal NMDA receptor blockade: relevance for schizophrenia

Transl Psychiatry. 2019 Feb 21;9(1):99. doi: 10.1038/s41398-019-0436-3.

Abstract

Dysfunction of prefrontal parvalbumin (PV+) interneurons has been linked with severe cognitive deficits as observed in several neurodevelopmental disorders including schizophrenia. However, whether a specific aspect of PV+ neurons deregulation, or a specific molecular mechanism within PV+ neurons is responsible for cognitive deficits and other behavioral impairments remain to be determined. Here, we induced cognitive deficits and altered the prefrontal PV system in mice by exposing them neonatally to the NMDA receptor antagonist ketamine. We observed that the cognitive deficits and hyperactivity induced by neonatal ketamine were associated with a downregulation of Npas4 expression specifically in PV+ neurons. To determine whether Npas4 downregulation-induced dysfunction of PV+ neurons could be a molecular contributor to the cognitive and behavioral impairments reported after neonatal ketamine, we used a transgenic Cre-Lox approach. Reduced Npas4 expression within PV+ neurons replicates deficits in short-term memory observed after neonatal ketamine, but does not reproduce disturbances in general activity. Our data show for the first time that the brain-specific transcription factor Npas4 may be an important contributor to PV+ neurons dysfunction in neurodevelopmental disorders, and thereby could contribute to the cognitive deficits observed in diseases characterized by abnormal functioning of PV+ neurons such as schizophrenia. These findings provide a potential novel therapeutic target to rescue the cognitive impairments of schizophrenia that remain to date unresponsive to treatments.

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Cognitive Dysfunction / metabolism*
  • Disease Models, Animal
  • Interneurons / metabolism*
  • Ketamine / pharmacology*
  • Male
  • Maze Learning
  • Memory, Short-Term / drug effects
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Motor Activity / drug effects
  • Parvalbumins / metabolism
  • Prefrontal Cortex / metabolism
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*
  • Receptors, N-Methyl-D-Aspartate / genetics
  • Schizophrenia / metabolism*

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Npas4 protein, mouse
  • Parvalbumins
  • Receptors, N-Methyl-D-Aspartate
  • Ketamine