Biology subjects

Nakashima, A.

Publications and source records attributed to Nakashima, A..

3 recordsLinked to original sources

bioRxiv2025

NT5DC2 downregulation suppresses monoamine oxidase activity and increases catecholamine levels in PC12D cells

Back groundGenome-wide association studies have revealed the involvement of 5-nucleotidase domain-containing protein 2 (NT5DC2) in neuropsychiatric disorders such as schizophrenia and bipolar disorder; however, its function remains unclear. Recently, we found that NT5DC2 downregulation in PC12D cells increases catecholamine synthesis by promoting the activity of tyrosine hydroxylase and that monoamine oxidase A (MAO A) might bind to NT5DC2 using Affinity Purification-Mass Spectroscopy. Methods and ResultsWe investigated the role of NT5DC2 for MAO A activity in PC12D cells. Western blot analysis revealed that NT5DC2 primarily binds to the non-phosphorylated form of MAO A. siRNA-mediated NT5DC2 downregulation reduced MAO A activity, leading to decreased dopamine metabolism and increased noradrenaline synthesis. ConclusionOur findings suggest that NT5DC2 could affect both tyrosine hydroxylase and MAO A activity to control catecholamine synthesis. Therefore, our study provides valuable insights into disorders associated with catecholamine dysregulation, such as Parkinsons disease and neuropsychiatric disorders.

neuroscience↗

bioRxiv2019

Auxin-mediated rapid degradation of selective proteins in hippocampal neurons

Genetic manipulation of protein levels is a promising approach to identify the function of a specific protein in living organisms. Previous studies demonstrated that the auxin-inducible degron (AID) strategy provides rapid and reversible degradation of various proteins in fungi and mammalian mitotic cells. In this study, we employed this technology to postmitotic neurons to address whether the AID system could be applied to the nervous system. Using adeno-associated viruses, we simultaneously introduced EGFP fused with an AID tag, and an F-box family protein, TIR1 from Oryza sativa (OsTIR1) into hippocampal neurons. In dissociated hippocampal neurons, EGFP fluorescence signals rapidly decreased when adding a plant hormone, auxin. Further, auxin-induced EGFP degradation was also observed in hippocampal acute slices. Taken together, these results open the door for neuroscientists to manipulate protein expression levels by the AID-system in a temporally-controlled manner.

neuroscience↗

bioRxiv2018

Sharp wave-associated activity patterns of olfactory cortical neurons in the mouse piriform cortex

The olfactory piriform cortex is thought to participate in olfactory associative memory. Like the hippocampus, which is essential for episodic memory, it belongs to an evolutionally conserved paleocortex and comprises a three-layered cortical structure. During slow-wave sleep, the olfactory piriform cortex becomes less responsive to external odor stimuli and instead displays sharp wave (SPW) activity similar to that observed in the hippocampus. Neural activity patterns during hippocampal SPW have been intensively studied in terms of memory consolidation; however, little is known about the activity patterns of olfactory cortical neurons during olfactory cortex sharp waves (OC-SPWs). In this study, we recorded multi-unit neural activities in the anterior piriform cortex in urethane-anesthetized mice. We found that the activity patterns of olfactory cortical neurons during OC-SPWs were non-randomly organized. Individual olfactory cortical neurons varied in the timings of their peak firing rates during OC-SPW events. Moreover, specific pairs of olfactory cortical neurons were more frequently activated together than expected by chance. On the basis of these observations, we speculate that coordinated activation of specific subsets of olfactory cortical neurons repeats during OC-SPWs, thereby facilitating synaptic plasticity underlying the consolidation of olfactory associative memories.

neuroscience↗