Biology subjects

Chen, M.

Publications and source records attributed to Chen, M..

At least 145 records · Page 8Linked to original sources

bioRxiv2025

ChromPolymerDB: A High-Resolution Database of Single-Cell 3D Chromatin Structures for Functional Genomics

The three-dimensional (3D) organization of chromatin plays a critical role in regulating gene expression and genomic processes like DNA replication, repair, and genome stability. Although these processes occur at the individual-cell level, most chromatin structure data are derived from population-averaged assays, such as Hi-C, obscuring the heterogeneity of single-cell conformations. To address this limitation, we developed a polymer physics-based modelling framework, the Sequential Bayesian Inference Framework (sBIF), that deconvolutes bulk Hi-C data to reconstruct single-cell 3D chromatin conformations. To support a broader use of sBIF, we created ChromPolymerDB, a publicly accessible, high-resolution database of single-cell chromatin structures inferred by sBIF. The database contains [~]108 reconstructed 5 kb-resolution single cell structures, spanning over 60,000 genomic loci across 50 human cell types and experimental conditions. ChromPolymerDB features an interactive web interface with tools for 3D structural analysis and multi-omics integration. Users can explore associations between chromatin conformation and gene expression, epigenetic modifications, and regulatory elements. The platform also supports comparative analyses to identify structural changes across cell types, developmental stages, or disease contexts. ChromPolymerDB offers a unique resource for researchers studying the relationship between genome architecture and gene regulation, and for advancing comparative 3D genomics. ChromPolymerDB is available online at https://chrompolymerdb.bme.uic.edu/. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=85 SRC="FIGDIR/small/678816v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@110c807org.highwire.dtl.DTLVardef@bc713forg.highwire.dtl.DTLVardef@1af0ea9org.highwire.dtl.DTLVardef@1eba638_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

Structural Insights into RubisCO Dynamics and Pyrenoid Architecture in Chlamydomonas reinhardtii

RubisCO is the key enzyme that catalyzes the conversion of atmospheric CO2 into organic carbon in photosynthetic organisms. To enhance RubisCO efficiency, eukaryotic algal species pack these enzymes within the pyrenoid, a specialized micro-compartment inside the chloroplast that enriches CO2 for carbon fixation. In the pyrenoid, RubisCO molecules are interconnected by linking peptides and form condensates through liquid-liquid phase separation (LLPS). Using a publicly available CryoET dataset of Chlamydomonas reinhardtii, we determine RubisCO structures at 6.5 [A] resolution, allowing the trace of the additional densities corresponding to the RubisCO-linking peptides. Through quantitative analysis of RubisCO spatial distribution, we revealed predominant arrangement patterns within the pyrenoid. Additionally, we characterized the structure of pyrenoid minitubules and examined how RubisCOs interact with the membrane network inside the pyrenoid, which facilitates the delivery of substrates for carbon fixation. This work provides valuable structural insights into the LLPS process and enhances our quantitative understanding of carbon fixation within the pyrenoid.

molecular biology↗

bioRxiv2025

ProTDyn: a foundation Protein language model for Thermodynamics and Dynamics generation

AO_SCPLOWBSTRACTC_SCPLOWMolecular dynamics (MD) simulation has long been the principal computational tool for exploring protein conformational landscapes and dynamics, but its application is limited by high computational cost. We present ProTDyn, a foundation protein language model that unifies conformational ensemble generation and multi-timescale dynamics modeling within a single framework. Unlike prior approaches that treat these tasks separately, ProTDyn allows flexible independent and identically distributed (i.i.d.) ensemble sampling and dynamic trajectory simulation. Across diverse protein systems, ProTDyn yields thermodynamically consistent ensembles, faithfully reproduces dynamical properties over multiple timescales, and generalizes to proteins beyond its training data. It offers a scalable and efficient alternative to conventional MD simulations. Code is available at: https://github.com/Harrydirk41/ProTDyn.

biochemistry↗

bioRxiv2025

Nicotinamide opposes ET-1's adverse effect on uterine decidualization via EDNRB

Endothelin-1 is involved in pathogenesis of preeclampsia. Mice (Edn1H/+) having excess endothelin-1 developed preeclampsia-like phenotypes during pregnancy in a maternal genotype-dependent manner. Here, we investigate whether decidualization is impaired in Edn1H/+ dams, and whether nicotinamide (a potent inhibitor of endothelin-1) exerts beneficial effect. We compared implantation sites between wild type (WT) and Edn1H/+ dams with or without nicotinamide treatment. Implantation sites of Edn1H/+ dams exhibited abnormal ectoplacental cone and sinusoids with reduced vascular density in mesometrial regions of deciduae. There was more VEGF in decidua of Edn1H/+ dams than WT dams. Markers of decidualization were decreased in Edn1H/+ dams. Nicotinamide supplementation corrected this abnormality. During differentiation (decidualization) of cultured human endometrial stomal cells, endothelin-1 impaired the upregulated expression of decidualization markers. The endothelin-1s effect was reversed by nicotinamide. These results show nicotinamide counteracts ET-1s detrimental effects on endometrial decidualization and has potential to improve embryo implantation and subsequent pregnancy outcomes.

developmental biology↗

bioRxiv2025

Structural dynamics of mitochondrial ATP synthase in Chlamydomonas reinhardtii revealed by in situ CryoET

The turbine dynamics of mitochondrial ATP synthases is an unresolved topic which in situ cryo-ET is poised to answer. Using publicly available tomogram data of vitrified Chlamydomonas reinhardtii cells, a monomer map of ATP synthase was refined to 6.67[A]. With extensive heterogeneity analysis, we characterized the in situ conformation states of F1 head, central stalk, and upper peripheral stalk (UPS) individually, and analyzed the by-particle correlation between movement of the different domains, revealing the complex dynamics of the system within cells. While oligomycin sensitivity conferral protein (OSCP) and the UPS were found to bend with F1 head rotation, coupling between the rotation of central stalk and F1 head rotational states, suggested by previous in vitro studies, were not detected from ATP synthase inside mitochondria.

cell biology↗

bioRxiv2025

Intrinsic interval timing, not temporal prediction, underlies ramping dynamics in visual and parietal cortex

Ramping neural activity is widely interpreted as a signature of predictive processing, but whether such signals truly reflect predictions or instead emerge from sensory mechanisms remains unclear. To address this question, we used two-photon calcium imaging across multiple cell types in visual and parietal cortex while awake mice passively received repeated audiovisual stimuli presented under distinct temporal structures. Neurons segregated into two broad response classes: stimulus-activated (ramp-down) and stimulus-inhibited (ramp-up) populations with diverse temporal kinetics. Multiple findings argued against a predictive interpretation: ramping activity was present in naive animals, neural responses changed immediately after short/long interval transitions, and unexpected stimulus timings elicited nearly identical responses in predictable and irregular contexts. Population analyses further showed that ramping reflected relaxation from stimulus-evoked activity rather than anticipatory buildup. Heterogeneous kinetics generated a robust population code for elapsed time. Together, these findings show that neural ramps during passive stimulation arise from stimulus-evoked dynamics that intrinsically generate temporal signals, rather than from temporal predictive processing. TeaserRamping activity in visual-parietal cortex during passive stimulation arises from sensory responses, not predictive mechanisms.

neuroscience↗

bioRxiv2025

Hypoimmunogenic human motor neurons induced from iPSCs in vivo substantially ameliorate ALS disease in large animal models

Stem cell-based therapy holds great potential for substituting degenerated motor neurons (MNs) in amyotrophic lateral sclerosis (ALS). Missing protocols for advanced differentiation of transplanted cells into MNs, immune rejection, and the lack of suitable ALS models for preclinical trials have slowed the development of effective therapies. Here, we employed multiplex genetic-editing to generate a novel human pluripotent stem cell line containing doxycycline (Dox)-inducible MNs-specific transcription factors and comprehensively modified immunomodulatory genes. We transplanted these cells into the spinal cord of ALS large animal models (SOD1G93A pigs and TIA1P362L rabbits), which faithfully recapitulate pathologies and symptoms observed in ALS patients. The transplanted cells could efficiently differentiate into functional MNs upon Dox treatment in vivo, distribute throughout the spinal cord and motor cortex via extensive migration, survive long-term without the need for immunosuppression. Notably, these MNs integrated into host neural circuits, as evidenced by their long projection of peripheral axons to target muscle and reformation of neuromuscular junctions. As result, pathologies and motor deficits were substantially ameliorated in both animal models. One Sentence SummaryHypoimmunogenic human motor neurons induced from iPSCs in vivo reform neuromuscular junctions and ameliorate ALS disease in pig and rabbit models.

neuroscience↗

bioRxiv2025

Microbial profiling and single-cell transcriptomics reveal probiotic mechanisms of coral thermal resilience

Probiotics hold promise for enhancing coral resilience under climate-driven thermal stress, yet their mechanisms remain poorly understood. Here, we evaluate two Endozoicomonas species as coral probiotics and characterize their effects on microbial communities and host gene expression. We show that E. acroporae Acr-14T enhances thermal tolerance in Stylophora pistillata, suppresses opportunistic pathogens, and promotes beneficial microbes. To facilitate transcriptomic profiling, we assembled a chromosome-level genome of S. pistillata clade 1 (Pacific lineage) and used it to reveal that E. acroporae Acr-14T mitigates heat-induced protein-folding stress and supports host energy homeostasis. Single-cell transcriptomics further uncovered enhanced pro-survival signaling and modulation of the S-adenosylmethionine (SAMe) synthesis pathway. Together, our findings identify E. acroporae Acr-14T as a robust coral probiotic and provide mechanistic insights into host-microbe interactions that promote coral resilience under thermal stress.

microbiology↗

bioRxiv2025

The anti-phage mechanism of a widespread trypsin-MBL module

Protease mediate activation of immune effectors is a conserved mechanism across life. This study identified a widespread and co-evolving trypsin-MBL module as a core effector in diverse bacterial immune systems (e.g., Hachiman, Argonaute, AVAST), protecting host via abortive infection. Focusing on Hachiman-trypsin-MBL, we demonstrated that, the protease activity of trypsin*HamAB is inhibited in the presence of ATP and MBL is an autoinhibited DNase with two inserted loops blocking the catalytic pocket. Upon infection, the HamB helicase senses invading nucleic acids and catalyzes the hydrolysis of ATP, activating the associated trypsin-like protease that cleaves specifically at two non-canonical KSS motif of MBL and releases its DNase activity. Cryo-EM structures of activated trypsin*HamAB bound with DNA reveal DNA binding and ATP hydrolysis lead to the release of the trypsin-like domain, enabling activation. Our work provides a comprehensive understanding on the mechanism of widely distributed trypsin-MBL module, wherein proteolytic activation of a toxic nuclease enables robust bacterial immunity while preventing self-toxicity through multi-layered control.

biochemistry↗

bioRxiv2025

DeepHalo: Deep Learning-Powered Exploration of Halogenated Metabolites Uncovering Antibacterial Depsipeptides

In the omics era, confident high-throughput analytical tools are crucial for the efficient identification of metabolites. Here, we present DeepHalo, a deep learning-integrated and hierarchically optimized workflow designed for high-throughput exploration of halogenated metabolites from high-resolution mass spectrometry-based metabolomics. DeepHalo leverages deep learning models combined with a comprehensive scoring to enhance the reliability of halogen predictions. It integrates PyOpenMS for fast isotope pattern detection and incorporates a halogen-based dereplication algorithm with GNPS molecular networking to efficiently exploit and annotate halogenates from complex biological matrices. To validate its performance, DeepHalo was applied to explore halogenated metabolites from 1,296 microbial culture crude, leading to the discovery of six families of structurally diverse halogenated molecules. This included a new class of cyclic depsipeptides, aglomycins A-E, featuring rare 3-chloroanthranilic acid and/or epoxyvaline blocks. Additionally, a plausible biosynthetic pathway of aglomycins was proposed through bioinformatics analyses and targeted gene knockout experiments. Bioassays revealed that aglomycin A exhibits synergistic antibacterial activity with linezolid against vancomycin-resistant Enterococcus faecium (VRE) both in vitro and in vivo. We envision that DeepHalo (freely available at https://github.com/xieyying/DeepHalo) will become a powerful tool for accelerating the discovery of halogenated "dark matter".

biochemistry↗

bioRxiv2025

HPInet: Interpretable prediction of Host-Pathogen protein-protein Interactions using a transformer-based neural network

Gram-negative bacteria utilize a series of secretion systems (T1SS-T10SS) to deliver secreted effector proteins (T1SE-T10SE) into host cells, leading to infections and diseases. Understanding the interactions between these effector proteins and host proteins is crucial for unraveling the pathogenic mechanisms of bacterial pathogens. Despite advancements in sequencing technologies that have significantly enhanced our knowledge of effector protein diversity and structure, the molecular mechanisms underlying their interactions with human host proteins remain unclear. Experimental approaches to validate these interactions are labor-intensive, time-consuming, and insufficient to comprehensively map the extensive effector-host protein interaction (PPI) network. Additionally, specialized computational tools for predicting these interactions remain scarce. To address this gap, we developed HPInet, a transformer-based deep learning model for predicting interactions between bacterial effector proteins and human host proteins. HPInet introduces convolutional layers and global response normalization (GRN) into the feed-forward network (FFN) of the transformer architecture, enhancing the extraction of local sequence features. Compared to existing state-of-the-art methods, HPInet significantly improves prediction performance, increasing accuracy from 0.502 to 0.891 and boosting sensitivity by 35.3%. Furthermore, by leveraging the models attention mechanism, HPInet identifies critical residues at interaction sites, demonstrating its capability to capture local structural features of PPI sites solely from sequence information. To facilitate its application in research, HPInet has been implemented as a freely accessible web server available at https://bis.zju.edu.cn/hpinet. This platform provides a powerful and interpretable tool for studying effector-host protein interactions, offering valuable insights into bacterial pathogenesis and potential therapeutic targets.

bioinformatics↗

bioRxiv2025

A Precision Ultrasound-Localized Sonoporation-Equipment (PULSE) Enabling Intratumoral Delivery for Cancer Immunotherapy

Cancer immunotherapy offers a promising long-term treatment for solid tumors by activating the immune system, but side effects and systemic toxicity limit its broad clinical translation. While intratumoral delivery addresses these limitations, elevated stiffness within solid tumors continues to hinder both intracellular and extracellular delivery. Here, a novel therapeutic platform, the Precision Ultrasound-Localized Sonoporation-Equipment (PULSE), is presented to enable spatiotemporally controlled, ultrasound-mediated gene and drug delivery for intratumoral immunotherapy. The PULSE incorporates forward and sideward-looking miniaturized ultrasound transducers, integrated into either a 7-French catheter (cPULSE) or a 16-gauge needle (nPULSE), to minimally invasively sonicate a centimeter-sized tumor. Following the design, prototyping, and characterization of PULSE, its dual capability for intracellular and extracellular delivery is demonstrated through comprehensive in vitro cell-based sonoporation tests and phantom-based drug penetration tests. Luciferase assays (activity: ~104 RLU/g level) in the cell studies confirm significantly enhanced gene transfection with cPULSE, while increased dye diffusion (width: ~1 cm level) in the phantom tests validates improved perfusion with nPULSE. The reported PULSE shows promise for spatiotemporally precise, controlled, and localized therapeutic delivery in early-stage tumors for intratumoral immunotherapy.

bioengineering↗

bioRxiv2025

mGluR4-Npdc1 complex mediates α-synuclein fibril-induced neurodegeneration

Fibrils of misfolded -synuclein (-syn) accumulate in Parkinsons disease and other synucleinopathies, spreading between cells to template further misfolding and drive neurodegeneration. -syn fibril entry into healthy neurons is recognized as a key step in the disease process but remains ill-defined mechanistically. Here, we comprehensively assessed the membrane proteome for binding of -syn fibrils. Expression cloning identified mGluR4 and Npdc1 as plasma membrane proteins expressed by substantia nigra neurons capable of supporting high affinity -syn fibril binding. Moreover, mGluR4 and Npdc1 cellular signaling functions were titrated by the presence of extracellular fibrillary -syn. While striatal -syn fibril injection led to nigral dopamine neuron loss in wild type mice, deletion of either Grm4 or Npdc1 provided protection of dopamine neurons. We observed mGluR4 and Npdc1 to form a complex that regulates mGluR4 signaling. Cultured neurons lacking both Grm4 and Npdc1 fail to bind -syn fibrils, to accumulate phosphorylated -syn and to lose synapses. Transheterozygous Grm4, Npdc1 mice showed protection from nigral neuron loss after striatal -syn injection, demonstrating genetic interaction between the two binding proteins. On a transgenic -syn A53T background, double Grm4, Npdc1 heterozygosity robustly increased mouse survival, motor function and spinal motoneuron number. Thus, a cell surface mGluR4-Npdc1 complex participates in -syn neurodegeneration.

neuroscience↗

bioRxiv2025

Oncogenic H-Ras Reprograms Madin-Darby Canine Kidney (MDCK) Cell-derived Midbody Remnant Proteins Following Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is a highly conserved morphogenic process that allows highly polarized, immotile epithelial cells to transform into motile mesenchymal cells: it is a fundamental cellular process involved in embryonic development, tumour cell metastasis, organ fibrosis and tissue regeneration. To assess the contribution of secreted midbody remnants (MBRs) - a new class of membranous extracellular vesicle (EV) molecularly distinct from exosomes/small EVs - to the EMT process, we conducted a proteomic analysis of MBRs released from Madin-Darby canine kidney (MDCK) cells, and MDCK cells transformed with oncogenic H-Ras (21D1 cells). MBRs were harvested from cell culture media in milligram quantities using a continuous culture bioreactor device and purified using sequential centrifugation and buoyant density gradient centrifugation (OptiPrep). Gel-MS/MS protein profiling showed MDCK cell-MBRs reflect their epithelial origin (e.g., enriched CDH1, DSP, THBS1, OLCN, EPCAM proteins) and 21D1 cell-MBRs their mesenchymal phenotype (e.g., HRAS, VIM, MMP14, CDH2, WNT5A and enriched invasive and cell motility proteins). Prominent findings were the unique expression of the immune checkpoint protein NT5E/CD73 (ecto-5'-nucleotidase), and ser/thr kinases LIMK1/K2 in 21D1-MBRs (not present in MDCK cell-MBRs), and enrichment in Wnt signalling network proteins. Collectively, our findings suggest MBRs might play a previously unrecognized role in the EMT process. SignificanceO_LIEpithelial-to-mesenchymal transition (EMT) is a critical cell biological process that occurs during normal embryonic development and cancer progression. Our study describes, for the first time, the large-scale sequential purification of secreted midbody remnants (MBRs) and exosomes/sEVs from the in vitro cell line EMT model Madin-Darby canine kidney (MDCK) cells and MDCK cells transformed with oncogenic H-Ras (21D1 cells): GeLC-MS/MS protein profiling identified the repertoire of enriched MDCK-MBR proteins following EMT. C_LIO_LIMBRs display a proteome profile distinct from sEVs that is enriched with factors of the centralspindlin complex (KIF23.1, KIF4A, INCENP, CEP55, PLK1) and further include components of the mitochondrial network, cytokinesis, microtubule movement, and intercellular connection. C_LIO_LIIn the context of EMT, our data reveal simultaneous activation of EMT signalling pathways in MBRs including signalling receptor binding, regulation of cell differentiation, and Wnt, VEGF and PDGF signalling. C_LIO_LIWe identify several mesenchymal enriched networks in MBRs associated with focal adhesion, cell matrix, kinase activity, and cell shape/organisation, while epithelial derived MBRs are show enriched networks predominately associated with mitochondrial (processing/transport), midbody, and plasma membrane annotation. C_LIO_LIOur study sheds light on the signalling architecture of MBRs following oncogenic H- Ras-induced EMT: collectively, our data informs ongoing efforts to delineate oncogenic drivers of cancer initiation, progression, and metastasis. C_LI

cell biology↗

bioRxiv2025

A new typing scheme demonstrates high discriminatory power for Treponema pallidum subspecies

The global resurgence of treponematoses, particularly syphilis, poses a growing public health challenge. Despite recent advances in sequencing technologies, obtaining complete Treponema pallidum genome sequences for epidemiological studies remains time-consuming and challenging due to the difficulty related to procuring clinical samples with sufficient treponemal burden to fulfil the sequencing requirements. There is an urgent need for rapid, cost-effective and accessible typing methods suitable for laboratories with Sanger sequencing resources. Based on the analysis of 121 T. pallidum genomes from geographically diverse regions, we selected seven highly variable genes to form the basis of this new typing system. These seven genes show high discrimination capacity, identifying many allelic profiles among T. pallidum isolates. Importantly, the scheme employs a single-step PCR protocol for the amplification and sequencing of all seven targets enabling straightforward implementation in standard laboratory settings. The MLST was validated using a diverse set of T. pallidum clinical samples from across the globe. A significant proportion of the tested samples showed macrolide resistance, emphasizing the need for epidemiological surveillance. Utilizing this new tool, we have analyzed the genetic variation within and between populations of T. pallidum, considering the geographical origin of the samples. Population structure analysis revealed distinct genetic clusters, underlining complex transmission dynamics of T. pallidum, shaped by local epidemiological factors. The MLST scheme is publicly accessible through the PubMLST database, encouraging widespread adoption in standard laboratories due to this database being user-friendly, intuitive, and fast to implement. The novel MLST scheme offers a promising tool to advance the study of the molecular epidemiology of T. pallidum, facilitate tracking transmission, and establish a global surveillance network with the overall goal of strengthening public health interventions for syphilis control.

microbiology↗

bioRxiv2025

Molecular Basis for Asynchronous Chain Elongation During Rifamycin Antibiotic Biosynthesis

The rifamycin synthetase (RIFS) from the bacterium Amycolatopsis mediterranei is a large (3.5 MDa) multienzyme system that catalyzes over 40 chemical reactions to generate a complex precursor to the antibiotic rifamycin B. It is considered a hybrid enzymatic assembly line and consists of an N-terminal nonribosomal peptide synthetase loading module followed by a decamodular polyketide synthase (PKS). While the biosynthetic functions are known for each enzymatic domain of RIFS, structural and biochemical analyses of this system from purified components are relatively scarce. Here, we examine the biosynthetic mechanism of RIFS through complementary crosslinking, kinetic, and structural analyses of its first PKS module (M1). Thiol-selective crosslinking of M1 provided a plausible molecular basis for previously observed conformational asymmetry with respect to ketosynthase (KS)-substrate carrier protein (CP) interactions during polyketide chain elongation. Our data suggest that C-terminal dimeric interfaces--which are ubiquitous in bacterial PKSs--force their adjacent CP domains to co-migrate between two equivalent KS active site chambers. Cryogenic electron microscopy analysis of M1 further supported this observation while uncovering its unique architecture. Single-turnover kinetic analysis of M1 indicated that although removal of C-terminal dimeric interfaces supported 2-fold greater KS-CP interactions, it did not increase the partial product occupancy of the homodimeric protein. Our findings cast light on molecular details of natural antibiotic biosynthesis that will aid in the design of artificial megasynth(et)ases with untold product structures and bioactivities. Significance StatementBacteria use enzymatic assembly lines for the manufacture of complex and often medicinally active organic compounds. Their conserved modular design and biosynthetic logic suggest they evolved to be intrinsically reprogrammable. Yet, strategies to manipulate assembly-line product structures through protein engineering are still met with considerable challenges. This work investigates how a representative bacterial assembly line catalyzes an essential reaction during biosynthesis of the antibiotic rifamycin. Our data provide a molecular rationale for asynchronous C-C bond formation catalyzed by equivalent subunits of the homodimeric system while exposing new aspects of assembly line architecture. These findings represent a step closer towards the design of artificial assembly lines for sustainable production of user-defined chemicals.

biochemistry↗

bioRxiv2025

Latrophilin-2 Orchestrates Endothelial Flow-Mediated Smad1/5 Activation via Endoglin and Shank3

Fluid shear stress (FSS) from blood flow critically determines vascular morphology and function. FSS activates the Smad1/5 pathway maximally at physiological FSS through the BMP9/10 receptors Alk1 and Endoglin to promote vascular stability. We now report that the adhesion G protein-coupled receptor Latrophilin-2 (Lphn2), which mediates flow activation of the canonical junctional complex, is required for flow-mediated Smad1/5 activation in endothelial cells. Lphn2 physically associates with Endoglin and is required for Smad1/5 activation by FSS but not soluble BMP9. This regulation is independent of G-proteins but requires Lphn2s C-terminal PDZ binding motif. Endothelial-specific Lphn2 knockout reduces Smad1/5 activation in mice. In zebrafish embryos, loss of flow or Lphn2 knockout similarly reduced endothelial Smad1/5 activation, with no additive effect, indicating that Lphn2 mediates flow-induced activation in vivo. APEX2 proximity labeling revealed that the PDZ domain-containing scaffold protein Shank3 associated with Lphn2 under flow. Shank3 knockdown blocked flow-induced Smad1/5 activation in vitro and Shank3 global knockout mice exhibited reduced endothelial nuclear Smad1/5 and increased susceptibility to arteriovenous malformations. Lphn2 thus mediates flow-induced Smad1/5 activation and vessel stabilization through the scaffold protein Shank3, independently of G proteins. Together with the accompanying paper on Notch1, we conclude that Lphn2 confers FSS sensitivity to three of the major FSS pathways via distinct mechanisms.

cell biology↗

bioRxiv2025

Organism-wide spatiotemporal profiling of gene expression utilizing a X-CreERT2/Ai9 tracing system

This study utilizes a novel inducible X-CreERT2/Ai9 system to comprehensively delineate the spatial expression landscape of Fermt2, which encodes a key focal adhesion protein Kindlin-2, across organs in mice. We can confirm all known Kindlin-2-expressing cells and identify any previously unknown Kindlin-2-expressing cells and those that do not express Kindlin-2 in all tissues/organs in mice. We have developed this cost-effective, rapid, and high-fidelity system and implemented its first whole-organism application for comprehensive gene expression profiling. This work not only provides unprecedented insights into roles of Kindlin-2 in diverse physiologies and pathologies, but also establishes the inducible X-CreERT2/Ai9 system as a powerful paradigm-shifting platform for organism-wide pan-organ spatiotemporal expression profiling of any target genes encoding any proteins and micro-RNAs. By enabling high-resolution mapping of drug target expression, this system may lay critical groundwork for elucidating previously unknown adverse and beneficial effects of targeted therapies, offering transformative potential for precision medicine.

biochemistry↗