Biology subjects

Fuchigami, T.

Publications and source records attributed to Fuchigami, T..

3 recordsLinked to original sources

bioRxiv2024

Development of nanobodies against human Survivin, applicable to suppress cell proliferation.

Survivin, a member of the inhibitor of apoptosis protein (IAP) family, is overexpressed in many cancers, making it a valuable target for therapy and a biomarker for cancer diagnostics. As Survivin contributes to cancer development by inhibiting apoptosis and promoting rapid cell division, inhibiting its activity is a promising strategy to overcome cancer resistance to apoptosis and reduce tumor growth. In this study, we developed nanobodies targeting human Survivin using M13 phage display and deep sequencing to identify high-affinity binders. Seven nanobody clones were selected and evaluated through ELISA, western blotting, and immunostaining. Clones 7 and 15, which specifically bind the alpha-helix region of Survivin, effectively suppressed cell proliferation by disrupting cell cycle regulation, likely by interfering interaction with intracellular binding partners. These findings suggest that Survivin-targeting nanobodies hold potential as therapeutic agents for cancer treatment, offering a novel approach to inhibiting tumor growth through the disruption of Survivin-mediated processes.

cancer biology↗

bioRxiv2023

Ganglioside GD3 regulates neural stem cell quiescence and controls postnatal neurogenesis

The postnatal neural stem cell (NSC) pool hosts quiescent and activated radial glia-like NSCs contributing to neurogenesis throughout adulthood. However, the underlying regulatory mechanism during the transition from quiescent NSCs to activated NSCs in the postnatal NSC niche is not fully understood. Lipid metabolism and lipid composition play important roles in regulating NSC fate determination. Biological lipid membranes define the individual cellular shape and help maintain cellular organization and are highly heterogenous in structure and there exist diverse microdomains (also known as lipid rafts), which are enriched with sugar molecules, such as glycosphingolipids. An often overlooked but key aspect is that the functional activities of proteins and genes are highly dependent upon their molecular environments. We previously reported that ganglioside GD3 is the predominant species in NSCs and that the reduced postnatal NSC pools are observed in global GD3-synthase knockout (GD3S-KO) mouse brains. The specific roles of GD3 in determining the stage and cell-lineage determination of NSCs remain unclear, since global GD3S-KO mice cannot distinguish if GD3 regulates postnatal neurogenesis or developmental impacts. Here we show that inducible GD3 deletion in postnatal radial glia-like NSCs promotes the NSC activation, resulting in the loss of the long-term maintenance of the adult NSC pools. The reduced neurogenesis in the subventricular zone (SVZ) and the dentate gyrus (DG) of GD3S-conditional-knockout mice led to impaired olfactory and memory functions. Thus, our results provide convincing evidence that postnatal GD3 maintains the quiescent state of radial glia-like NSCs in the adult NSC niche. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/532547v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@15a6451org.highwire.dtl.DTLVardef@1702776org.highwire.dtl.DTLVardef@2edbb1org.highwire.dtl.DTLVardef@59822f_HPS_FORMAT_FIGEXP M_FIG C_FIG Main PointsO_LIRadial glia-like neural stem cells (RGLs) lacking GD3 promote activation of quiescent RGLs. C_LIO_LIPostnatal depletion of GD3 results in reduced neural stem cell pools and impaired adult neurogenesis. C_LIO_LIPostnatal GD3 deletion in RGLs leads to impairment of olfactory and memory functions. C_LI

neuroscience↗

bioRxiv2019

Genomic profiling of PML bodies reveals transcriptional regulation by PML bodies through the DNMT3A exclusion

The promyelocytic leukaemia (PML) body is a phase-separated nuclear structure involved in various biological processes, including senescence, and tumour suppression1. PML bodies consist of various proteins, including PML proteins and several chromatin regulators2,3 and physically associate with chromatin4,5, implying their crucial roles in particular genome functions. However, their roles in transcriptional regulation are largely unknown. Here, we developed APEX-mediated chromatin labelling and purification (ALaP), to identify the genomic regions associated with PML bodies. We find that PML bodies associate with active regulatory regions across the genome and prominently with a [~]300 kb of the short arm of the Y chromosome (YS300) in mouse embryonic stem cells (mESCs). The association with YS300 is essential for the transcriptional activities of neighbouring Y-linked cluster genes. Mechanistically, we show that PML bodies play a novel role in 3D nuclear organization by providing specific nuclear spaces that the de novo DNA methyltransferase DNMT3A cannot access, which results in the robust maintenance of the hypo-methylated states at the Y-linked gene promoters. Our study underscores a new mechanism for gene regulation in the 3D-nuclear space and provides insights into the functional properties of nuclear structures for genome functions.

cell biology↗