Biology subjects

Kakinuma, H.

Publications and source records attributed to Kakinuma, H..

4 recordsLinked to original sources

bioRxiv2026

Basal ganglia output guides decision-making by state destabilization

To execute learned behavior, the nervous system can undergo an activity-state transition between the current and the learned activity states. Here, using adult zebrafish, we show that their basal ganglia output induces such state transitions for goal-directed behavior. After learning the Go/No-go task in virtual reality, the striatal indirect pathway responds to negative values of a conditioned cue and the absence of sensory feedback by different neuronal populations. The pallidal output pathway integrates these negative value signals and then broadcasts the integrated signal to the Dc area in the pallium (fish cortex). Optogenetics and mathematical modeling suggested that this pallidal output activity uniformly destabilizes ongoing Dc activity states, thereby facilitating behavioral state transitions toward the behavioral state with the minimum pallidal output activity. This mechanism explains how pallidal output activity guides goal-directed behavior beyond potential barriers between activity states underlying different behavioral states.

neuroscience↗

bioRxiv2026

PDLIM5 Modulates YAP1 Localisation and Fibrogenic Gene Expression in Hepatic Stellate Cells

Hepatic stellate cells (HSCs) are the key cellular drivers of liver fibrosis. During liver injury and chronic inflammation HSCs adopt an activated phenotype and secrete fibrotic extracellular matrix (ECM) components such as collagen 1. Mechanical cues derived from the fibrotic ECM drive and support the activation of HSCs, via mechanisms that involve integrins and the mechano-sensitive transcriptional regulator YAP1. It is not yet well understood how external mechanical cues are translated into a molecular response that alters YAP1 nuclear shuttling. There is evidence that suggests the PDZ and LIM domain protein (PDLIM) 5 can regulate YAP1 shuttling in human epithelial cells. We therefore investigated whether PDLIM5 is expressed in HSCs and contributes to YAP1 associated HSC mechano-activation. PDLIM5 protein was detected in HSCs in fibrotic human and mouse liver. PDLIM5 transcript and protein were expressed by primary human and mouse HSCs and by the immortalised HSC LX-2 cell line. PDLIM5 localised with actin stress fibres suggesting a role in HSC adhesion. Co-immunoprecipitation and proximity ligation in LX-2 cells support an association between PDLIM5 and YAP1. We used pharmacological (paclitaxel) and genetic (siRNA and CRISPRi) approaches to inhibit PDLIM5 in HSCs. Inhibiting PDLIM5 reduced YAP1 nuclear localisation and fibrotic gene (COL1A1, ACTA2) expression in LX-2 cells. Overall, these data support a role for PDLIM5 in regulating YAP1 localisation and fibrogenic gene expression in HSCs.

cell biology↗

bioRxiv2023

Transgenic tools targeting striatal and pallidal subpopulations revealed evolutionary conservation and specialization of the cortico-basal ganglia circuit in zebrafish

The cortico-basal ganglia circuit mediates decision-making. Here, we generated transgenic tools for adult zebrafish targeting specific subpopulations of the components of this circuit and utilized them to identify evolutionary homologs of the mammalian direct- and indirect-pathway striatal neurons which respectively project to the homologs of the internal and external segment of the globus pallidus (dEN and Vl) as in mammals. Unlike in mammals, the Vl mainly projected to the dEN directly, not by way of the subthalamic nucleus. Further single-cell RNA sequencing analysis revealed two pallidal output pathways: a major shortcut pathway directly connecting the dEN with the pallium and the evolutionarily conserved closed loop by way of the thalamus. Our resources and circuit map provide the common basis for the functional study of the basal ganglia in a small and optically tractable zebrafish brain for the comprehensive mechanistic understanding of the cortico-basal ganglia circuit.

neuroscience↗

bioRxiv2019

Future state prediction errors guide active avoidance behavior by adult zebrafish.

Human predicts future. To ask if fish also has this capacity, we established the virtual reality training system with live imaging of the telencephalic neurons of adult zebrafish in the active avoidance and found that, at the onset of the trial, learned fish conceives two future conditions as the favorable status on its way to the safe goal, i.e. one with the backwardly moving landscape and the other with the color of the safe goal. And the two different neural ensembles monitor the discrepancy between these predictions and the perceived real external status. Once fish reaches the goal, another ensemble is set to work to monitor whether fish keeps staying in the safe goal. The manipulation to artificially enhance these prediction errors elevated the activities of these ensembles and induced fish to behave to correct errors, revealing that fish sets behavioral strategy to actively realize these predictions.

neuroscience↗