Biology subjects

Morikawa, H.

Publications and source records attributed to Morikawa, H..

3 recordsLinked to original sources

bioRxiv2019

Genome-wide identification and transcriptomic analysis of microRNAs across various amphioxus organs using deep sequencing

Amphioxus is the closest living invertebrate proxy of the vertebrate ancestor. Systematic gene identification and expression profile analysis of amphioxus organs is thus important for clarifying the molecular mechanisms of organ function formation and further understanding the evolutionary origin of organs and genes in vertebrates. The precise regulation of microRNAs (miRNAs) is crucial for the functional specification and differentiation of organs. In particular, those miRNAs that are expressed specifically in organs (OSMs) play key roles in organ identity, differentiation, and function. In this study, the genome-wide miRNA transcriptome was analyzed in eight organs of adult amphioxus Branchiostoma belcheri using deep sequencing. A total of 167 known miRNAs and 23 novel miRNAs (named novel_mir), including 139 conserved miRNAs, were discovered, and 79 of these were identified as OSMs. Additionally, analyses of the expression patterns of eight randomly selected known miRNAs demonstrated the accuracy of the miRNA deep sequencing that was used in this study. Furthermore, potentially OSM-regulated genes were predicted for each organ type. Functional enrichment of these predicted targets, as well as further functional analyses of known OSMs, was conducted. We found that the OSMs were potentially to be involved in organ specific functions, such as epidermis development, gonad development, muscle cell development, proteolysis, lipid metabolism and generation of neurons. Moreover, OSMs with non-organ specific functions were detected, and primarily include those related to innate immunity and response to stimuli. These findings provide insights into the regulatory roles of OSMs in various amphioxus organs.

genetics↗

bioRxiv2019

Automated acquisition of knowledge beyond pathologists

Deep learning algorithms have been successfully used in medical image classification and cancer detection. In the next stage, the technology of acquiring explainable knowledge from medical images is highly desired. Herein, fully automated acquisition of explainable features from annotation-free histopathological images is achieved via revealing statistical distortions in datasets by introducing the way of pathologists examination into a set of deep neural networks. As validation, we compared the prediction accuracy of prostate cancer recurrence using our algorithm-generated features with that of diagnosis by an expert pathologist using established criteria on 13,188 whole-mount pathology images. Our method found not only the findings established by humans but also features that have not been recognized so far, and showed higher accuracy than human in prognostic prediction. This study provides a new field to the deep learning approach as a novel tool for discovering uncharted knowledge, leading to effective treatments and drug discovery.

bioinformatics↗

bioRxiv2017

Acute Social Stress Engages Synergistic Activity of Stress Mediators in the VTA to Promote Pavlovian Reward Learning

Stressful events rapidly trigger activity-dependent synaptic plasticity in certain brain areas, driving the formation of aversive memories. However, it remains unclear how stressful experience affects plasticity mechanisms to regulate learning of appetitive events, such as intake of addictive drugs or palatable foods. Using rats, we show that two acute stress mediators, corticotropin-releasing factor (CRF) and norepinephrine (NE), enhance plasticity of NMDA receptor-mediated glutamatergic transmission in the ventral tegmental area (VTA) through their differential effects on inositol 1,4,5-triphosphate (IP)-dependent Ca2+ signaling. In line with this, acute social defeat stress engages convergent CRF and NE signaling in the VTA to enhance learning of cocaine-paired cues. Furthermore, defeat stress enables learning of a food-paired cue with no delay between the cue onset and food delivery. We propose that acute stress mediators synergistically regulate IP3-Ca2+ signaling in the VTA to promote appetitive Pavlovian conditioning, likely enabling learning of cues with no predictive value.

neuroscience↗