Biomedical subjects

Yuishin Izumi

Publications and source records attributed to Yuishin Izumi.

3 recordsLinked to original sources

PubMed2026

Improved protocol for isolation and characterization of human thymic epithelial cells.

Thymic epithelial cells (TECs) play a vital role in the generation of immunocompetent and immunotolerant T cells. The understanding of TEC biology in model animals such as mice has advanced thanks to the cellular and molecular analyses of purified TEC populations, including cortical TECs (cTECs) and medullary TECs (mTECs). On the other hand, studies of human TECs have fallen behind because of the lack of a well-established method for purifying TEC populations. Here, we show that using 0.5 U/mL liberase to digest thymus tissue into single cells is quicker than using collagenase D or 0.1 U/mL liberase. Thymus digestion with 0.5 U/ml liberase preserves CD205 expressed by cTECs. RNA sequencing analysis of TEC populations isolated from 0.5 U/mL liberase-digested human thymic tissue revealed the expression of molecules known as cTEC- and mTEC-specific genes in mouse thymus in each human TEC population. Our study is expected to fuel further cellular and molecular studies of human TECs, including those related to the collapse of immune tolerance in humans.

Flow cytometry↗

PubMed2026

Base editing rescues a hereditary motor neuron disease in mouse and patient-derived iPSC organoid models.

In hereditary motor neuron diseases (MNDs), including forms of amyotrophic lateral sclerosis (ALS) caused by single-nucleotide variants, effective therapeutic strategies need to address both gain- and loss-of-function mechanisms. Genome editing-based gene therapy represents a promising approach for simultaneously targeting these mechanisms. To establish proof-of-concept for base editing in a hereditary MND, we targeted the P285L variant in the TRK-fused gene (TFG), which causes hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P), a disorder that shares clinical and histopathological features with ALS. We identified the optimal adenine base editor by comparing candidate editors in HMSN-P patient-derived induced pluripotent stem cells (iPSCs). We then generated a transgenic mouse model expressing human TFG P285L and evaluated the selected editor by subpial delivery of adeno-associated virus (AAV) vectors to the spinal cord. AAV-mediated base editing prolonged survival, preserved motor neurons, and attenuated axon loss in ventral nerve roots. Treatment with the selected base editing vector reduced TFG aggregation and suppressed neuronal death in HMSN-P iPSC-derived neuromuscular organoids. Collectively, these findings support the therapeutic potential of base editing for hereditary MNDs.

AAV↗

PubMed2025

A case of Baraitser-Winter cerebrofrontofacial syndrome diagnosed by whole-exome sequencing.

Here we report a heterozygous missense variant in the ACTB gene, NM_001101.5:c.209C>T (p.Pro70Leu), detected in a case of a mildly affected infant with Baraitser-Winter cerebrofrontofacial syndrome, characterized by unique craniofacial features, coloboma and mild developmental delay, but without lissencephaly. Baraitser-Winter cerebrofrontofacial syndrome cases with a similar mild phenotype have been reported to have the same variant in different populations, suggesting a genotype-phenotype correlation in this syndrome.

Journal Article↗