Biology subjects

XU, T.

Publications and source records attributed to XU, T..

4 recordsLinked to original sources

bioRxiv2026

Rewiring c-Myc Transcriptional Activity with an O-GlcNAcylation Targeting Chimera (OGTAC)

c-Myc is a transcription factor that drives tumorigenesis in many cancers. It is notoriously difficult to directly target c-Myc, mainly due to its lack of well-defined druggable pockets. O-linked {beta}-N-acetylglucosamine modification (O-GlcNAcylation) is a post-translational modification (PTM) playing an important role in regulating c-Myc functions in cancer. However, previous studies have primarily relied on global perturbations to investigate c-Myc O-GlcNAcylation, making it difficult to determine its direct functional consequences due to concurrent cellular effects. Here, we report a bifunctional O-GlcNAcylation TArgeting Chimera (OGTAC) molecule, which can induce the proximity of c-Myc and O-GlcNAc transferase (OGT) in living cells, thereby enhancing the O-GlcNAcylation of c-Myc. The c-Myc-targeting OGTAC exhibits anti-proliferation effect against cancer cells. Mapping of c-Myc occupancy on genome indicates that OGTAC rewires c-Myc transcriptional activity and reprograms expression of the downstream oncogene MALAT1, in an O-GlcNAcylation-dependent manner. Overall, OGTAC presents a novel chemically induced proximity (CIP)-based tool to target and rewire c-Myc activity in cancer. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/722559v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@d1c640org.highwire.dtl.DTLVardef@2eb70corg.highwire.dtl.DTLVardef@f38970org.highwire.dtl.DTLVardef@c421c8_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Preemptive SOD1 Silencing via Neonatal Intramuscular AAV Therapy Modifies Disease Trajectory in an ALS Mouse Model

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disorder with limited therapeutic options. Mutations in the gene encoding superoxide dismutase 1 (SOD1) represent a major genetic cause of familial ALS, driving motor neuron degeneration through toxic gain-of-function mechanisms. Although gene silencing approaches targeting SOD1 show substantial therapeutic potential, their clinical translation remains restricted by suboptimal delivery to the spinal motor neurons and safety concerns linked to conventional viral vectors. This study presents a minimally invasive gene therapy strategy that combines the retrograde transport capability of rAAV2-retro with the safety of an artificial microRNA (miRNA) to achieve pan-spinal SOD1 silencing. A single intramuscular injection of rAAV2-retro-miRNA into neonatal SOD1G93A mice resulted in widespread transduction of spinal motor neurons, significant reduction of mutant SOD1 protein, and multifaceted therapeutic benefits. Treated mice exhibited delayed disease onset, extended lifespan, preserved motor function, reduced neuroinflammation, and protection of neuromuscular junctions and spinal motor neurons. Importantly, the artificial miRNA construct demonstrated a superior safety profile relative to short hairpin RNA (shRNA)-based constructs, which induced marked toxicity and lethality in wild-type mice. These findings establish neonatal intramuscular delivery of rAAV2-retro-miRNA as a safe, efficient, and clinically translatable strategy for preemptive intervention in SOD1-mediated ALS, offering broader applicability to other motor neuron diseases.

neuroscience↗

bioRxiv2025

Imaging throughput of compact handheld microscopes for quantitative single cell studies

High-throughput live-cell imaging within incubator environments often necessitates a compromise between optical resolution and instrument/computational complexity. In this work, we demonstrate that controlled defocusing, a default function in all optical microscopes, can be utilized as a primary contrast mechanism for large-scale cell analysis (7000 cells per field of view). Our results suggest that even at a low numerical aperture (NA [~] 0.01) and using just epi-illumination, defocused images can generate a uniform negative contrast across the cell body. This negative contrast improves automated cell segmentation efficiency over a wide field of view compared to in-focus imaging. We further evaluated the accessibility of this defocus imaging approach for both 2D and 3D cultures by implementing an automated cell segmentation protocol on a commercial off-the-shelf digital Universal Serial Bus (USB) microscope. The compact form factor of the digital USB microscope facilitates minimal pixel sampling, enabling high-throughput single-cell detection and continuous tracking across a large adherent cell population over several days. Our assessments of the utility of defocus imaging for 2D and 3D tissue cultures were further supported by monitoring the negative contrast changes during the migration and dissociation of 3D tissue spheroids. Our results show that negative contrast profiles from defocus images enable the quantification of cell proliferation, division, migration, and cell-to-cluster dissociation within standard culture environments. This defocusing methodology offers a scalable approach to extensive high-content screening through simplified instrumentation controls. Key pointsO_LIDefocused images of adherent cells using low NA optics homogenizes intracellular intensity hotspots, creating uniform negative contrast for whole cell segmentation; similar to shadow imaging in fluorescence. C_LIO_LIInverting look-up-table (LUT) combined with defocus imaging on large population of adherent cells in standard culture flask taken by standard digital USB microscopes allow for rapid, routine tracking of thousands of cells per field of view. C_LIO_LINegative contrast image profiles from defocusing enable the quantification cell proliferation, division, migration for 2D monolayer and 3D tissue spheroid cultures. C_LI

biophysics↗

bioRxiv2022

Whole-Brain Map of Top-down afferent Inputs to Nucleus Accumbens of the Mouse

Nucleus accumbens (NAc) is an important part of basal ganglia and receives major transsynaptic inputs from medial prefrontal cortex (mPFC), basolateral amygdala nucleus (BL) and hippocampus (HPC). The neural circuits formed by mPFC, BL, HPC with NAc are closely related to diverse brain functions such as decision-making, social behavior, reward seeking behavior and aggressive behavior. However, a lack of information about network structure of NAc top-down afference has limited our understanding of mechanisms of these functions. Here, we systematically analyzed whole brain patterns of inputs to mPFC/HPC/BL-NAc projectors via using (TRIO) labeling strategy. We found that the upstream input patterns between mPFC-core and mPFC-shell projections, BL-core and BL-shell projections, HPC-core and HPC-shell projections were similar. The projections from mPFC and BL to NAc receive a wide range of inputs, while the projections from HPC to NAc receive convergent inputs. Furthermore, all of mPFC/HPC/BL-NAc projectors receive considerable inputs from respective local regions. This study lays a foundation for further analysis of complex NAc functional mechanisms.

neuroscience↗