Biology subjects

Kuroyanagi, H.

Publications and source records attributed to Kuroyanagi, H..

5 recordsLinked to original sources

bioRxiv2026

Ramelteon facilitates hippocampal ripple occurrence and amplitude in mice

The hippocampus is essential for memory consolidation, a process mediated by high-frequency oscillations known as ripples during non-rapid eye movement (NREM) sleep. Ramelteon, a selective MT1/MT2 receptor agonist, has been reported to possess cognitive-enhancing properties; however, its impact on the fine-scale dynamics of hippocampal ripples remains unclear. We performed chronic local field potential recordings from the dorsal hippocampus and prefrontal cortex in mice. Following the intraperitoneal administration of either vehicle or ramelteon, we evaluated sleep architecture and characterized ripple properties, including occurrence rate, amplitude, instantaneous frequency, and duration during NREM sleep. Ramelteon administration significantly increased NREM sleep occupancy. Notably, we found that ramelteon significantly enhanced both the occurrence rate and amplitude of hippocampal ripples compared to the control group. While a slight increase in intra-ripple frequency was observed, other structural features, such as ripple duration and asymmetry index, remained unaffected. Our findings demonstrate that ramelteon facilitates hippocampal ripple dynamics by increasing their occurrence and synchrony during NREM sleep. Given the critical role of ripples in memory consolidation, these neurophysiological changes may underlie the procognitive effects of ramelteon. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=55 SRC="FIGDIR/small/723673v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@77b58org.highwire.dtl.DTLVardef@132dbc1org.highwire.dtl.DTLVardef@1f98dc1org.highwire.dtl.DTLVardef@c9a3f2_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2024

NAD+ - and EVA1-C-dependent reversal of neurological deficits is mediated by differential alternative RNA splicing in tauopathic animal models

Aberrant alternative splicing (ASEs) is an aging hallmark to Alzheimers Disease (AD). Although NAD+ and related metabolites can slow down AD, NAD+ on ASEs in AD remain unclear. Mouse transcriptomic data revealed NR-induced ASEs, focusing on the Eva1-C locus. AI-based algorithms predicted EVA1-C protein structures and protein-protein interactions. AD postmortem brain samples and tauopathy models including transgenic mice and worm was used for validation. NAD+ abundance/metabolic status modulates ASEs and the expression of EVA1-C isoforms, which in turn regulate the interaction with BAG-1 and HSP70 proteins. Importantly, EVA1-C is dramatically reduced in 20 Braak 5/6 AD patients compared to cognitive normal humans in different brain regions. NAD+ metabolism modulates abundance of specific mRNA isoforms, and that ASEs influence disease progression in model tauopathies and potentially AD. These results could facilitate future development of NAD+-based splice-switching therapeutics for AD. TeaserUnveiling the Link Between NAD+ Metabolism and Alzheimers Disease: Discovering the Role of Alternative RNA Splicing in Disease Progression and Potential Therapeutic Targets

neuroscience↗

bioRxiv2023

A hyperpolarizing neuron recruits undocked innexin hemichannels to transmit neural information in Caenorhabditis elegans

While depolarization of neuronal membrane is known to evoke the neurotransmitter release from synaptic vesicles, hyperpolarization is regarded as a resting state of chemical neurotransmission. Here we report that hyperpolarizing neurons can actively signal neural information by employing undocked hemichannels. We show that UNC-7, a member of the innexin family in Caenorhabditis elegans, functions as a hemichannel in thermosensory neurons and transmits temperature information from the thermosensory neurons to their post-synaptic interneurons. By monitoring neural activities in freely behaving animals, we find that hyperpolarizing thermosensory neurons inhibit the activity of the interneurons and that UNC-7 hemichannels regulate this process. UNC-7 is required to control thermotaxis behavior and functions independently of synaptic vesicle exocytosis. Our findings suggest that innexin hemichannels mediate neurotransmission from hyperpolarizing neurons in a manner that is distinct from the synaptic transmission, expanding the way of neural circuitry operations.

neuroscience↗

bioRxiv2023

Simultaneous measurement of nascent transcriptome and translatome using 4-thiouridine metabolic RNA labeling and translating ribosome affinity purification

Regulation of gene expression in response to various biological processes, including extracellular stimulation and environmental adaptation requires de novo RNA synthesis and translation. Analysis of the coordinated and circular regulation of dynamic RNA synthesis and translation is required to determine functional protein production. However, reliable methods for the simultaneous measurement of nascent RNA synthesis and translation at the gene level are limited. Here, we developed a novel method for the simultaneous assessment of nascent RNA synthesis and translation by combining 4-thiouridine (4sU) metabolic RNA labeling and translating ribosome affinity purification (TRAP) using a monoclonal antibody against evolutionarily conserved ribosomal P-stalk proteins. The P-stalk-mediated TRAP (P-TRAP) technique recovered endogenous translating ribosomes, allowing easy translatome analysis of various eukaryotes. We validated this method in mammalian cells by demonstrating that acute unfolded protein response (UPR) in the endoplasmic reticulum (ER) induces dynamic reprograming of nascent RNA synthesis and translation. Our method can serve as a simple and powerful tool for analyzing the coordinated regulation of transcription and translation of individual genes in various eukaryotes.

molecular biology↗

bioRxiv2022

Genetic screens identified dual roles of MAST kinase and CREB within a single thermosensory neuron in the regulation of C. elegans thermotaxis behavior

Animals integrate sensory stimuli presented at the past and present, assess the changes in their surroundings and navigate themselves toward preferred environment. Identifying the molecular and circuit mechanisms of such sensory integration is pivotal to understand how the nervous system generates perception and behavior. Previous studies on thermotaxis behavior of Caenorhabditis elegans suggested that a single thermosensory neuron AFD plays an essential role in integrating the past and present temperature information and is essential for the neural computation that drives the animal toward the preferred temperature region. However, the molecular mechanisms by which AFD executes this neural function remained elusive. Here we report multiple forward genetic screens to identify genes required for thermotaxis. We reveal that kin-4, which encodes the C. elegans homolog of MAST kinase, plays dual roles in thermotaxis and can promote both cryophilic and thermophilic drives. We also uncover that a thermophilic defect of mutants for mec-2, which encodes a C. elegans homolog of stomatin, can be suppressed by a loss-of-function mutation in the gene crh-1, encoding a C. elegans homolog CREB transcription factor. Calcium imaging analysis from freely-moving animals suggest that mec-2 and crh-1 function in AFD and regulate the neuronal activity of its post-synaptic interneuron AIY. Our results suggest that a stomatin family protein can control the dynamics of neural circuitry through the transcriptional regulation within a sensory neuron.

genetics↗