Biology subjects

LU, H.

Publications and source records attributed to LU, H..

6 recordsLinked to original sources

bioRxiv2026

FLASH radiotherapy drives intestinal regeneration via macrophage-derived WNT4 signaling and attenuated T-cell inflammation

Ultra-high dose rate radiotherapy (FLASH-RT) reduces normal-tissue toxicity, yet how elevated dose rate improves tissue repair remains unclear. Here we combined whole-abdominal FLASH-RT and conventional radiotherapy (CONV-RT) in mice with single-cell transcriptomics, trajectory analysis, cell-cell communication inference, and in vivo perturbation experiments to define the intestinal repair ecosystem. Compared with CONV-RT, FLASH preserved Lgr5+ intestinal stem cells and Fabp1+ absorptive epithelial cells. Trajectory analysis showed that FLASH maintained stem-cell differentiation toward mature epithelial states enriched for fatty-acid metabolism. During a day-3 repair window, FLASH was accompanied by enrichment of Mrc1 macrophages, increased WNT4-associated signaling involving Fzd5Lrp5/6-expressing stem cells, and early transient {beta}-catenin activation. In vivo augmentation of Wnt4 signaling promoted crypt regeneration after CONV-RT. FLASH also reduced Tcf7 and Tbx21 CD4 T-cell populations and TNF- levels, consistent with attenuation of the pro-inflammatory CD4 T-cell response during intestinal recovery. Together, these findings indicate that FLASH-associated tissue sparing involves coordinated remodeling of regenerative and inflammatory immune states, suggesting that radiation dose rate influences not only initial tissue injury but also the immune microenvironment of subsequent recovery. Targeting this immune-stem cell crosstalk may provide a strategy to mimic FLASH-like radioprotection.

biophysics↗

bioRxiv2026

Conformational drugging pockets at the surface of c-MYC proto-oncongenes

The MYC proto-oncogene encodes a master transcription factor essential for regulating cellular homeostasis, growth, and metabolism. However, its deregulation is involved in up to 70% of human cancers, where it drives uncontrolled cellular proliferation. Structurally, MYC is characterized by an N-terminal transactivation domain and a C-terminal bHLHLZ domain critical for DNA binding and dimerization with MAX. Despite its clinical significance, MYC has remained historically "undruggable" due to its intrinsically disordered structure and the absence of traditional binding pockets. In this study, we combined all-atom Molecular Dynamics and well-tempered Metadynamics simulations to map the conformational landscape of a MYC motif in aqueous ionic solution. The selected energy-minimised structures exhibit stable conformations and drug pockets, providing structural foundations for targetting c-MYC, which is traditionally considered "undruggable". Furthermore, both the electrostatic potential and docking results for the obtained structure and the MYC inhibitor 10074-G5 demonstrated excellent fit, highlighting its potential as a drug target. Remarkably, MYC maintained steady binding to 10074-G5 throughout the 500 ns simulation. These findings provide a previously uncharacterized structural foundation for the design of innovative therapeutic interventions, such as small-molecule inhibitors or peptides aimed at disrupting oncogenic MYC activity.

cancer biology↗

bioRxiv2025

A coupled fluorescence assay for high-throughput screening of polyurethane-degrading enzymes

The global accumulation of plastic waste, particularly persistent polymers like polyurethane (PU), demands urgent solutions. Enzymatic depolymerization offers a viable strategy for PU waste valorization. However, progress has been hindered by the lack of reliable high-throughput screening (HTS) assays capable of precise and quantitative evaluation of enzymatic activity. Current enzyme screening assays face significant limitations due to poor substrate relevance and inadequate quantification methods. Here, we present a novel HTS assay featuring a chemically defined, synthetic poly (ethylene adipate)-based PU substrate that enables unambiguous structure-activity analysis and direct quantification of degradation products (adipic acid and ethylene glycol). Coupled with this substrate is a highly sensitive fluorescence-based detection cascade, in which released ethylene glycol is stoichiometrically converted to resorufin via a two-enzyme system (glycerol dehydrogenase and diaphorase). This assay overcomes key limitations of commercial substrates (e.g., Impranil DLN) by providing quantitative, real-time monitoring of PU hydrolysis with molecular precision. Validation with known PU-degrading enzymes demonstrated that the assay can sensitively distinguish differences in enzymatic activity with high reproducibility and quantitative accuracy. Our platform enables rapid, cost-effective screening of enzyme libraries and engineered variants, significantly advancing enzyme discovery and optimization efforts. By bridging the gap between laboratory research and industrial application, this HTS assay accelerates the development of sustainable PU recycling solutions, offering a critical tool against plastic pollution. Graphical Abstract Legend O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/663332v4_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@17ba5c0org.highwire.dtl.DTLVardef@bef89aorg.highwire.dtl.DTLVardef@1b3770eorg.highwire.dtl.DTLVardef@14d5ef5_HPS_FORMAT_FIGEXP M_FIG (A) Workflow of the enzymatic degradation assay. Enzymes are incubated with chemically defined PEA-PU films. The resulting hydrolysate is collected and analysed using a fluorescence-based assay in microplate format (Ex/Em = 535/588 nm). (B) Fluorescence-based detection mechanism. Assay principle based on ethylene glycol (EG), one of the major degradation products. EG is converted through a two-step enzymatic cascade involving glycerol dehydrogenase (GldA) and diaphorase, leading to the generation of fluorescent resorufin from resazurin. C_FIG

synthetic biology↗

bioRxiv2024

Free energy profiles of temozolomide crossing brain plasma membranes

Temozolomide is an efficient small-molecule drug mostly employed for the treatment of glioblastoma, a tumor attacking both the spinal cord and the brain. Understanding the interactions of temozolomide with different lipids at the brain cell membrane can help elucidate how temozolomide permeates through cell membranes and its membrane-crossing ability. In the present work, we have constructed a simplified brain plasma membrane model to explore temozolomides microscopic structure and dynamics by means of all-atom microsecond scale molecular dynamics simulations. The preferential location of temozolomide is at the solvent-aqueous fluid surrounding the brain membrane, but it can access the interface with the membrane regularly, eventually binding to lipids of the choline and cerebroside classes. The free energy barriers of temozolomide related to brain-like plasma membrane crossing were investigated by adaptive biasing force methods, revealing values ranging from 18.5 to 66.5 kcal/mol at temperatures of 323 K and 310 K, respectively. Our results suggest that temozolomide cannot cross the membrane by pure diffusion at the normal human body temperature but that rising the temperature significantly increases the probability of barrier crossing. This fact is mainly due to the crucial role played by cholesterol and lipids of the cerebroside class. The findings reported in this work can be used to optimize the molecular design of temozolomide and to develop new analogs with better pharmacokinetic properties. Author summaryGlioblastoma is a devastating tumor affecting the brain and spinal cord, which has in the FDA-approved drug temozolomide its main clinical treatment. The present study explores how temozolomide interacts with several lipids in brain-like cell membranes. Our findings show that at normal body temperature temozolomide cannot cross the membrane by pure diffusion, but that higher temperatures significantly enhance its ability to cross the membrane by reducing the free energy barriers. Temozolomide interacts differently with several lipids and sterols depending on the temperature, which affects its permeability. This implies that temozolomide will cross the outer layer of the brain membrane only with the help of driving agents, such as intermembrane proteins. Our research suggests that temozolomide may be more effective at higher temperatures and cancer patients with fever might need a lower dose. Importantly, cholesterol plays a key role in blocking temozolomide from crossing brain-like membranes, so reducing dietary intake of cholesterol and cerebroside lipids could help modify brain cell membranes, making it easier for temozolomide to target cancer cells effectively and potentially reducing side effects.

biophysics↗

bioRxiv2024

Localization and function of key axonemal microtubule inner proteins and dynein docking complex members reveal extensive diversity among vertebrate motile cilia

Vertebrate motile cilia are broadly classified as (9+2) or (9+0), based on the presence or absence of the central pair apparatus, respectively. Cryogenic electron microscopy (cryo-EM) analyses of (9+2) cilia have uncovered an elaborate axonemal protein composition; whether these features are relevant to (9+0) cilia remain unclear. We previously demonstrated that Cfap53, a key microtubule inner protein (MIP) as well as centriolar-satellites component, is essential for motility of (9+0), but not (9+2) cilia. Here, we show that in (9+2) cilia, Cfap53 functions redundantly with a paralogous MIP, Mns1. Mns1 localizes to ciliary axonemes, and combined loss of both proteins in zebrafish and mice, caused severe loss of outer dynein arms (ODAs) of (9+2) cilia, significantly affecting their motility. Moreover, using immunoprecipitation, we demonstrate that while Mns1 can self-associate and interact with Cfap53, Cfap53 is unable to self-associate. Finally, we show that multiple additional dynein interacting proteins, such as the ODA docking complex (ODA-DC) members, show strikingly distinct localization patterns between various motile cilia-types. Our findings clarify how paralogous MIPs, Cfap53 and Mns1, function in regulating motility of (9+2) versus (9+0) cilia, and establish that localization pattern of other key motility proteins also differ between these cilia-types, further emphasizing extensive structural variations among these organelles.

developmental biology↗

bioRxiv2020

Coronatine is More Potent than Jasmonates in Regulating Arabidopsis Circadian Clock

Recent studies establish a crucial role of the circadian clock in regulating plant defense against pathogens. Whether pathogens modulate host circadian clock as a potential strategy to suppress host innate immunity is not well understood. Coronatine is a toxin produced by the bacterial pathogen Pseudomonas syringae that is known to counteract Arabidopsis defense through mimicking defense signaling molecules, jasmonates (JAs). We report here that COR preferentially suppresses expression of clock-related genes in high throughput gene expression studies, compared with the plant-derived JA molecule methyl jasmonate (MJ). COR treatment dampens the amplitude and lengthens the period of all four reporters tested while MJ and another JA agonist JA-isoleucine (JA-Ile) only affect some reporters. COR, MJ, and JA-Ile act through the canonical JA receptor COI1 in clock regulation. These data support a stronger role of the pathogen-derived molecule COR than plant-derived JA molecules in regulating Arabidopsis clock. Further study shall reveal mechanisms underlying COR regulation of host circadian clock.

plant biology↗