Biology subjects

Sugimura, S.

Publications and source records attributed to Sugimura, S..

3 recordsLinked to original sources

bioRxiv2025

Early transcriptional divergence underlies cell fate bias in bovine embryos

Developmental plasticity, or the ability of early embryonic cells to contribute to multiple lineages, is traditionally considered equal among sister blastomeres during early cleavage. However, divergence may occur earlier than expected. We performed single-cell RNA sequencing of bovine embryos from the 2- to 8-cell stages to examine transcriptional asymmetry. While gene expression was uniform at the 2-cell stage, variability increased at the 4-cell stage and became pronounced by the 8-cell stage. At this stage, blastomeres showed heterogeneity in MAPK pathway genes (e.g., RAC1, MAPK14) and the trophectoderm marker CDX2. These differences were associated with blastomere size; larger blastomeres more frequently initiated cavity formation, a functional marker of trophectoderm fate. Our findings suggest that both molecular and physical asymmetries contribute to early lineage bias, and that developmental plasticity may be lost in an asynchronous, cell-specific manner before visible morphological events such as compaction.

developmental biology↗

bioRxiv2025

Repetitive stimulation modifies network characteristics of neural organoid circuits

Neural organoids form complex networks but lack external stimuli and hierarchical structures crucial for refining functional microcircuits. In this study, we modeled the hierarchical and modular network organization by connecting multiple organoids and tested if the connection enhances the external stimuli-induced network refinement. We cultured networks of one, two, or three organoids on high-density microelectrode arrays, applied repetitive stimulation at two input locations from the microelectrodes, and monitored emergence of output signals that can decode the stimulus locations with machine learning algorithms. After two weeks of daily stimulation, networks of three organoids showed significantly higher stimulus decoding capability compared to the simpler one- or two-organoid networks. Long-term stimulation induced pronounced changes in the three-organoid networks response patterns, spontaneous activity, and inter- and intra-organoid functional connectivity. These findings underscore the importance of hierarchical network organization, e.g. creating distinct subnetworks with specialized roles, for stimuli-induced formation of circuits with robust input-output functionality.

bioengineering↗

bioRxiv2024

Compatibility of time-lapse dry incubator on in vitro production of bovine embryos

Embryo culture is crucial to achieve successful outcomes in assisted reproductive technology (ART) for cattle. This study explored the innovative use of dry incubators integrated with time-lapse monitoring systems for bovine embryo culture, building on their advantages in human medicine, such as reduced contamination risk, stable temperature control, and lower gas consumption. Our research demonstrates the feasibility of this approach, showing that although the osmotic pressure gradually increases over the culture period, it remains below the critical threshold for developmental impairment. Embryos cultured in dry incubators exhibited morphokinetics comparable to those cultured in conventional humidified time-lapse incubators. Furthermore, RNA-seq revealed that the transcriptomic profiles of blastocysts cultured in dry incubators closely matched those of blastocysts cultured in humidified incubators. These findings highlight the significant potential of dry incubators with time-lapse monitoring systems for the in vitro production of bovine embryos, marking a promising advancement in assisted reproductive technologies for the livestock industry and research setting.

developmental biology↗