Biology subjects

Kikuta, K.

Publications and source records attributed to Kikuta, K..

3 recordsLinked to original sources

bioRxiv2025

Immune Composition of the Mononuclear Cell Fraction of Human Umbilical Cord Blood

Despite its therapeutic potential and unique immunological properties, the immune composition of umbilical cord blood lacks consistent and comprehensive characterizations. Human umbilical cord blood (UCB) is often discarded after delivery and is difficult to obtain for research purposes. Furthermore, most research on UCB is focused on properties of CD34+ hematopoietic stem cells for transplantation. The Binns Program for Cord Blood Research at Stanford University has the unique advantage of regular collection and isolation of mononuclear cells (MNC) from UCB donors. This study provides a robust characterization of the immune subset compositions of the CD34-negative MNC fraction of UCB (n=50). The study also compares the UCB data to adult peripheral blood (PB) mononuclear cells to identify differences in immune maturity. Using flow cytometry and single-cell RNA sequencing (scRNA-Seq), we analyzed UCB and adult PB MNC samples to characterize the cell surface protein and transcriptomic profiles of different immune subsets. Our study findings bring a higher-definition understanding of the unique immunological properties of umbilical cord blood. Study findings reveal a distinct immune profile in UCB, such as a higher average percentage of CD19 B Lymphocytes, CD4 T Cells, CD4 Naive T Cells, CD4 Recent Thymic Emigrants, CD8 Naive T Cells, CD8 Recent Thymic Emigrants, and CD19 Naive B Cells compared to adult PB. Additionally, there were fewer CD19 Memory B Cells in UCB compared to PB. The scRNA-Seq showed concordance in the proportion of immune cell types but captured more differentiated subtypes of cells. Additionally, scRNA-Seq showed unique clustering patterns in UCB, which reflect cell types that converge in adulthood as the immune system matures. These analyses yield the intriguing possibility that the immune heterogeneity of individuals at birth gives way to more stereotyped immune subsets as the immune system is exposed to the external environment and undergoes maturation. Overall, our findings provide a robust characterization of MNC UCB immune subsets and insights into how immune function develops from birth to adulthood.

immunology↗

bioRxiv2024

Synaptic input architecture of visual cortical neurons revealed by large-scale synapse imaging without backpropagating action potentials

How neurons integrate thousands of synaptic inputs to compute sharply tuned outputs is a critical question in sensory information processing. To answer this question, it is essential to record the location and activity of synaptic inputs in vivo. However, back-propagating action potential (BAP) calcium signals invade dendrites and spines, making accurate recording of spine responses difficult. In this study, we first developed a new method to record spine calcium responses without BAP signals. Using this method, we performed large-scale imaging of visually evoked spine activity from layer 2/3 pyramidal neurons and revealed three patterns of dendritic functional architectures of synaptic inputs: dendrites with clusters of spines of similar responses, dendrites with spines of diverse responses, and dendrites with spines where the majority of them show no visual response. Our model suggests that only a small fraction of spines on dendrites of clustered architectures are sufficient to generate sharply tuned output.

neuroscience↗

bioRxiv2024

Discovery and characterization of stereodefined PMO-gapmers targeting tau

Antisense oligonucleotides (ASOs) are an important class of therapeutics to treat genetic diseases, and expansion of this modality to neurodegenerative disorders has been an active area of research. To realize chronic administration of ASO therapeutics to treat neurogenerative diseases, new chemical modifications improving activity and safety profile are still needed. Furthermore, it is highly desirable to develop a single stereopure ASO with defined activity and safety profile to avoid any efficacy and safety concerns due to the batch-to-batch variation in the composition of diastereomers. Herein, a stereopure PMO-gapmer was developed as a new construct to improve safety and stability by installing charge-neutral PMOs at the wing region and by fully controlling phosphorus stereochemistries. The developed stereopure PMO-gapmer construct was applied to the discovery of ASO candidates for the reduction of microtubule-associated protein tau (MAPT, tau). Sequence screening targeting MAPT followed by screening of optimal phosphorus stereochemistry identified stereopure development candidates. While evaluating the stereopure PMO-gapmers, we observed a dramatic difference in safety profile among stereoisomers in which only one phosphorus stereochemistry differs. These results further highlight the benefits of developing stereopure ASOs as safe and well-characterized candidates for clinical studies.

neuroscience↗