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Hayama, T.

Publications and source records attributed to Hayama, T..

3 recordsLinked to original sources

Comprehensive Molecular Docking on the AlphaFold-Predicted Protein Structure Proteome: Identifying Target Protein Candidates for Puberulic Acid, a Suspected Lethal Nephrotoxin

This study presents a novel in silico screening method for identifying potential protein-ligand interactions within the complete structural proteome, as predicted by AlphaFold2, using puberulic acid as a test case. The methodology utilizes molecular docking simulations to predict interactions based on structural compatibility and binding affinity estimations. This approach highlights proteins, such as sodium/myo-inositol cotransporters, which exhibit theoretical high affinity for puberulic acid, suggesting possible competitive inhibition or mimetic interactions that could disrupt osmoregulation. It is important to clarify that these simulations provide a hypothetical framework for understanding potential interactions. The high docking scores do not directly translate to biological effects but serve as a basis for further experimental validation. This cautious interpretation acknowledges the inherent limitations of predictive modeling while maintaining confidence in the robustness of the computational process. Moreover, the exploratory nature of this study is supported by the fact that binding affinity predictions are not influenced by protein amino acid length or the predictive accuracy (pLDDT scores) provided by AlphaFold2. This independence from structural prediction metrics suggests that the docking results offer a reliable exploration of potential interactions across a wide array of proteins, making this approach a valuable asset in the fields of drug discovery and toxicological research. The ability to comprehensively identify candidate proteins with potential affinity to chemical compounds enhances the predictive capacity of toxicological assessments and supports the strategic development of safer pharmaceutical agents.

bioinformatics↗

Self-organization, quality control, and preclinical studies of human iPSC-derived retinal sheets for tissue-transplantation therapy

Three-dimensional retinal organoids (3D-retinas) are a promising graft source for transplantation therapy. We previously developed self-organizing culture for 3D-retina generation from human pluripotent stem cells (hPSCs). Here we present a quality control method and preclinical studies for tissue-sheet transplantation. Self-organizing hPSCs differentiated into both retinal and off-target tissues. Gene expression analyses identified the major off-target tissues as eye-related, cortex-like, and spinal cord-like tissues. For quality control, we developed a qPCR-based test in which each hPSC-derived neuroepithelium was dissected into two tissue-sheets: inner-central sheet for transplantation and outer-peripheral sheet for qPCR to ensure retinal tissue selection. During qPCR, tissue-sheets were stored for 3-4 days using a newly developed preservation method. In a rat tumorigenicity study, no transplant-related adverse events were observed. In retinal degeneration model rats, retinal transplants differentiated into mature photoreceptors and exhibited light responses in electrophysiology assays. These results demonstrate our rationale toward self-organizing retinal sheet transplantation therapy.

neuroscience↗

Stringent structural plasticity of dendritic spines revealed by two-photon glutamate uncaging in adult mouse neocortex in vivo

Two-photon uncaging of glutamate is widely utilized to characterize structural plasticity in brain slice preparations in vitro. In this study, we investigated spine plasticity by using, for the first time, glutamate uncaging in the neocortex of adult mice in vivo. Spine enlargement was successfully induced in a smaller fraction of spines in the neocortex (22%) than in young hippocampal slices (95%), even under a low magnesium condition. Once induced, the time course and mean amplitudes of long-term enlargement were the same (81%) as those in vitro. However, low-frequency (1-2 Hz) glutamate uncaging caused spine shrinkage in a similar fraction (34%) of spines as in vitro, but spread to the neighboring spines less frequently than in vitro. Thus, we found that structural plasticity can occur similarly in the adult neocortex in vivo as in the hippocampus in vitro, although it happens stringently in a smaller subset of spines.

neuroscience↗