Shati/Nat8l deficiency disrupts adult neurogenesis and causes attentional impairment through dopaminergic neuronal dysfunction in the dentate gyrus
JOURNAL OF NEUROCHEMISTRY
Authors: Wulaer, Bolati; Kunisawa, Kazuo; Hada, Kazuhiro; Suento, Willy Jaya; Kubota, Hisayoshi; Iida, Tsubasa; Kosuge, Aika; Nagai, Taku; Yamada, Kiyofumi; Nitta, Atsumi; Yamamoto, Yasuko; Saito, Kuniaki; Mouri, Akihiro; Nabeshima, Toshitaka
Abstract
Successful completion of daily activities relies on the ability to select the relevant features of the environment for memory and recall. Disruption to these processes can lead to various disorders, such as attention-deficit hyperactivity disorder (ADHD). Dopamine is a neurotransmitter implicated in the regulation of several processes, including attention. In addition to the higher-order brain function, dopamine is implicated in the regulation of adult neurogenesis. Previously, we generated mice lacking Shati, an N-acetyltransferase-8-like protein on a C57BL/6J genetic background (Shati/Nat8l(-/-)). These mice showed a series of changes in the dopamine system and ADHD-like behavioral phenotypes. Therefore, we hypothesized that deficiency of Shati/Nat8l would affect neurogenesis and attentional behavior in mice. We found aberrant morphology of neurons and impaired neurogenesis in the dentate gyrus of Shati/Nat8l(-/-) mice. Additionally, research has suggested that impaired neurogenesis might be because of the reduction of dopamine in the hippocampus. Galantamine (GAL) attenuated the attentional impairment observed in the object-based attention test via increasing the dopamine release in the hippocampus of Shati/Nat8l(-/-) mice. The alpha 7 nicotinic acetylcholine receptor antagonist, methyllycaconitine, and dopamine D1 receptor antagonist, SCH23390, blocked the ameliorating effect of GAL on attentional impairment in Shati/Nat8l(-/-) mice. These results suggest that the ameliorating effect of GAL on Shati/Nat8l(-/-) attentional impairment is associated with activation of D1 receptors following increased dopamine release in the hippocampus via alpha 7 nicotinic acetylcholine receptor. In summary, Shati/Nat8l is important in both morphogenesis and neurogenesis in the dentate gyrus and attention, possible via modulation of dopaminergic transmission.
Investigating DNA Methylation of SHATI/NAT8L Promoter Sites in Blood of Unmedicated Patients with Major Depressive Disorder
BIOLOGICAL & PHARMACEUTICAL BULLETIN
Authors: Miyanishi, Hajime; Uno, Kyosuke; Iwata, Mina; Kikuchi, Yuu; Yamamori, Hidenaga; Yasuda, Yuka; Ohi, Kazutaka; Hashimoto, Ryota; Hattori, Kotaro; Yoshida, Sumiko; Goto, Yu-ichi; Sumiyoshi, Tomiki; Nitta, Atsumi
Abstract
Major depressive disorder (MDD) is one of the most common psychiatric diseases. However, early detection and diagnosis of MDD is difficult, largely because there is no known biomarker or objective diagnostic examination, and its diagnosis is instead based on a clinical interview. The aim of this study was to develop a novel diagnostic tool using DNA methylation as a blood biomarker. We sought to determine whether unmedicated patients with MDD showed significant differences in DNA methylation in the promoter region of the SHATI/N-acetyltransferase 8 like (SHATI/NAT8L) gene compared to healthy controls. Sixty participants with MDD were recruited from all over Japan. They were diagnosed and assessed by at least two trained psychiatrists according to DSM-5 criteria. DNA was extracted from peripheral blood. We then assessed DNA methylation of the SHATI/NAT8L promoter regions in patients with MDD by pyrosequencing. Methylation levels of the SHATI/NAT8L promoter region at CpG sites in peripheral blood from unmedicated patients were significantly higher than in healthy controls. In contrast, medicated patients with MDD showed significantly lower methylation levels in the same region compared to healthy controls. Since previous studies of DNA methylation in MDD only assessed medicated patients, the methylation status of the SHATI/NAT8L promoter region in unmedicated patients presented herein may prove useful for the diagnosis of MDD. To our knowledge, this is the first attempt to measure methylation of the SHATI/NAT8L gene in drug-naive patients with psychiatric diseases. Based on our findings, methylation of SHATI/NAT8L DNA might be a diagnostic biomarker of MDD.