Regulation of habenular G-protein gamma 8 on learning and memory via modulation of the central acetylcholine system

Abstract

Guanine nucleotide binding protein (G protein) gamma 8 (Gng8) is a subunit of G proteins and expressed in the medial habenula (MHb) and interpeduncular nucleus (IPN). Recent studies have demonstrated that Gng8 is involved in brain development; however, the roles of Gng8 on cognitive function have not yet been addressed. In the present study, we investigated the expression of Gng8 in the brain and found that Gng8 was predominantly expressed in the MHb-IPN circuit of the mouse brain. We generatedGng8knockout (KO) mice by CRISPR/Cas9 system in order to assess the role of Gng8 on cognitive function.Gng8KO mice exhibited deficiency in learning and memory in passive avoidance and Morris water maze tests. In addition,Gng8KO mice significantly reduced long-term potentiation (LTP) in the hippocampus compared to that of wild-type (WT) mice. Furthermore, we observed that levels of acetylcholine (ACh) and choline acetyltransferase (ChAT) in the MHb and IPN ofGng8KO mice were significantly decreased, compared to WT mice. The administration of nAChR alpha 4 beta 2 agonist A85380 rescued memory impairment in theGng8KO mice, suggesting that Gng8 regulates cognitive function via modulation of cholinergic activity. Taken together, Gng8 is a potential therapeutic target for memory-related diseases and/or neurodevelopmental diseases.