Biology subjects

Xing, L.

Publications and source records attributed to Xing, L..

At least 19 recordsLinked to original sources

bioRxiv2026

Therapeutic Potential of iPSC-Derived TH+FOXA2+ Neuronal Extracellular Vesicles in Parkinson's Disease Revealed by Organoid and Rodent Models

Background: Parkinson's disease (PD) is characterized by the progressive loss of midbrain dopaminergic (DA) neurons and aberrant alpha-synuclein (alpha-syn) aggregation, yet disease-modifying therapies that simultaneously retard neurodegeneration and foster regeneration remain lacking. Methods: In this study, we isolated extracellular vesicles (TH and FOXA2 double-positive cell-derived EVs) from TH and FOXA2 double-positive differentiated neural cells, a distinct midbrain floor-plate-derived neural cell population that co-expresses the floor-plate transcription factor FOXA2 together with TH and should therefore not be equated with conventional mature midbrain dopaminergic neurons, and systematically evaluated their therapeutic potential across three complementary models: A53T transgenic mice, 6-OHDA-lesioned rats, and 6-OHDA-treated human midbrain organoids. Integrative transcriptomic and single-cell sequencing analyses, together with toxicological evaluations in rodents and non-human primates, were performed to investigate the underlying mechanisms and safety profile. These TH and FOXA2 double-positive cells were generated using a fully suspension-based, matrix-free, and chemically defined differentiation system devoid of N2/B27 supplements and fetal bovine serum (FBS). This approach offers a simple, controllable, low-cost, and scalable platform with high batch-to-batch consistency for EV manufacturing. Throughout this study, the term "TH and FOXA2 double-positive cells" refers to this distinct TH and FOXA2 double-positive cell population and should not be interpreted as conventional terminally differentiated dopaminergic neurons. Results: Intranasal administration of TH and FOXA2 double-positive cell-derived EVs in A53T mice and 6-OHDA-lesioned rats significantly ameliorated motor deficits, increased nigral tyrosine hydroxylase (TH)-positive neuron counts, reduced alpha-syn aggregation, and suppressed gliosis. In human midbrain organoids, TH and FOXA2 double-positive cell-derived EVs preserved DA neuronal morphology and reduced GFAP and alpha-syn expression. Notably, when EVs were administered simultaneously with 6-OHDA modeling rather than after modeling was completed, the protective effect was stronger. Multi-omics analysis revealed that TH and FOXA2 double-positive cell-derived EVs reversed pathological signatures of interferon-responsive microglia and oxidative stress-adapted astrocytes, while restoring WNT- and non-canonical WNT-mediated intercellular communications. Safety evaluations showed no discernible organ toxicity. Conclusions: TH and FOXA2 double-positive cell-derived EVs exert neuroprotective effects across multiple PD models by modulating specific glial subpopulations and reinstating development-associated signaling pathways. Together with a fully suspension-based, matrix-free, and N2/B27-free differentiation process that enables low-cost, scalable, and highly reproducible manufacturing, TH and FOXA2 double-positive cell-derived EVs represent a promising therapeutic candidate for Parkinson's disease.

neuroscience↗

bioRxiv2026

Zyxin and LPP differ in their sensing of strained actin filaments at tricellular junctions

The actomyosin cytoskeleton plays important roles in cell-cell adhesion by generating and responding to forces. Actin-binding proteins support actomyosin networks by reinforcing actin filaments, promoting actin remodeling, and transmitting forces to transmembrane adhesion proteins. One family of actin-binding proteins, LIM domain-containing proteins, is recruited to strained actin filaments. Here, we investigate two members of the LIM domain family, Zyxin and Lipoma-Preferred Partner (LPP), using the embryonic epithelium of Xenopus laevis, where actin-associated cell-cell junctions connect cells to promote tissue integrity and barrier function. Specifically, we compare Zyxin and LPP's response to increased tension at tricellular junctions (TCJs), sites of heightened mechanical strain within the tissue. Upon increased tension, Zyxin and LPP mechanoaccumulate to different extents relative to F-actin, suggesting distinct mechanisms. Our results demonstrate that Zyxin's and LPP's LIM domain-containing regions (LCRs) are sufficient for mechanoaccumulation as well as responsible for the difference in mechanoaccumulation, while their N-termini play a regulatory role in their mechanosensitive responses. Docking simulations show that a hydrophobic interaction between the LCR and the "crack site" that forms in F-actin filaments under high force may underlie the LCR's sensing of strained F-actin. Additionally, the docking simulations reveal that previously-identified conserved residues are present at the binding interface. Mutations of conserved residues in Zyxin or LPP reduce the extent of mechanoaccumulation at TCJs, supporting the docking prediction. Together, this study advances our understanding of Zyxin and LPP's sensing of strained actin at TCJs under mechanical challenge.

cell biology↗

bioRxiv2026

Translation sustains productive Pol II elongation through maintenance of nuclear RNA surveillance

Although transcription and translation are spatially separated in eukaryotic cells, gene expression requires coordination between the nucleus and cytoplasm. Whether translation rapidly influences nuclear transcription remains unclear. Here we show that ongoing translation sustains productive RNA polymerase II (Pol II) elongation in mouse embryonic stem cells. Translation inhibition reduces nascent transcription within 15 minutes, impairs Pol II pause release, and preferentially represses long genes before substantial loss of chromatin-associated Pol II. Unexpectedly, despite reduced transcription, nuclear RNA transiently accumulates owing impaired in RNA turnover. Mechanistically, translational arrest redistributes RNA-processing and RNA-surveillance factors from the nucleus to stalled ribosome-associated complexes in the cytoplasm, reducing their nuclear availability. Acute depletion of RNA-surveillance components phenocopies elongation defects caused by translational inhibition, particularly in long genes. Together, our findings identify ongoing translation as a regulator of nuclear RNA surveillance capacity and reveal a feedback mechanism sustaining productive Pol II elongation and nuclear RNA homeostasis.

Molecular Biology↗

bioRxiv2026

Perturbation of genes linked to common schizophrenia risk variants identifies cilia programs

Schizophrenia (SCZ) is a common psychiatric disorder characterized by psychosis, emotional withdrawal, and cognitive deficits. Most SCZ risk variants reside in non-coding regions of the genome and are thought to influence disease risk by modulating gene regulation. However, the target genes, biological pathways, and cell types through which these variants exert their effects remain poorly understood. To address this gap, we employed in vivo CRISPR droplet sequencing (CROP-seq) in the postnatal mouse neocortex. We perturbed 12 SCZ risk genes previously linked to functionally validated risk variants, followed by single-cell RNA sequencing. We identified 3,031 differentially expressed genes (DEGs) that recapitulate transcriptional alterations observed in postmortem SCZ brains. Integrative analysis using DEG clustering, factor analysis, and gene regulatory network inference uncovered convergent gene programs with distinct biological functions and cell type specificity. Notably, ciliary transcriptional programs consistently emerged across analytical frameworks. The primary cilium is a neurocircuit modulating signaling organelle in neurons and glia that remains understudied in SCZ. Perturbation of key contributors to the ciliary transcriptional programs led to significant alterations in ciliary structure, suggesting that SCZ genetic risk factors may influence how brain cells sense and transduce extracellular signals through synapse-independent mechanisms. Together, this study provides the first in vivo characterization of the functional consequence of common variant architecture in SCZ and implicates ciliary dysfunction as a convergent downstream mechanism.

neuroscience↗

bioRxiv2026

A generalized life-motion mechanism supports invariant directional coding of local biological kinematics in humans

Humans can detect biological motion (BM) from sparse local kinematic cues, yet whether the visual system encodes directional information in a category-invariant manner remains unresolved. Here we combined a visual adaptation paradigm with computational modelling to reveal direction-sensitive neural mechanisms specialized for local biological kinematics. Adapting to a side-view scrambled point-light walker produced a robust repulsive aftereffect in the perceived direction of an intact human walker near the frontal view. Notably, this aftereffect generalized across different terrestrial vertebrates (pigeon, cat, dog) and across various actions (running, crawling, cycling), demonstrating a high degree of kinematic invariance. Crucially, the effect disappeared when biological kinematics were disrupted (inversion or removal of gravitational acceleration cues) or when the test stimulus was replaced with non-biological object motion. Individuals direction-discrimination abilities were also highly correlated across diverse local BM patterns, indicating a shared underlying mechanism. Drift-diffusion modeling further revealed that adaptation primarily altered the efficiency of sensory evidence accumulation rather than decision-level processes, and individual drift-rate changes strongly predicted the magnitude of perceptual aftereffects. These findings provide compelling evidence for a generalized, direction-sensitive neural system tuned to local biological kinematics, extending the life-motion detector theory and revealing a fundamental principle of biological motion perception. Significance StatementHumans possess an exceptional ability to detect and interpret the movements of living beings--an ability fundamental to survival, social interaction, and adaptive behavior. But how does the visual system extract "life motion" so adeptly amidst the complexity of natural scenes? Using visual adaptation and computational modelling, we provide direct evidence for direction-sensitive neural mechanisms specialized for local biological kinematics. These mechanisms operate robustly across species and actions, and remain selective for natural biological dynamics. Our findings advance the life-motion detector theory by demonstrating that the human visual system encodes directional information in a highly invariant manner, revealing a fundamental computational strategy for detecting animate agents.

neuroscience↗

bioRxiv2026

Chd8 haploinsufficiency leads to molecular layer heterotopias and age-dependent cortical expansion

Mutations in the chromatin remodeler CHD8 are associated with autism and macrocephaly. While mouse models of Chd8 haploinsufficiency recapitulate brain overgrowth, the specific cellular mechanisms and developmental timing that lead to these anatomical abnormalities remain poorly understood. Here, we conducted 3D imaging of Chd8V986*/+ mouse brains using magnetic resonance imaging followed by tissue clearing and cellular resolution light-sheet microscopy across embryonic and postnatal developmental stages. We found that brain overgrowth occurs postnatally, driven by an increase in non-neuronal cells prior to volumetric expansion. Unexpectedly, we identified prevalent molecular layer heterotopias (MLH) within the frontal cortex of Chd8V986*/+ mice composed of neurons breaking through the pial surface during embryonic development and persisting throughout life. Increased incidence of MLH, previously identified in individuals with idiopathic autism, was replicated across three independent Chd8+/- mouse models and present across multiple genomic backgrounds, establishing aberrant neuronal migration as a core feature of Chd8 haploinsufficiency.

neuroscience↗

bioRxiv2026

Decoding the MYC locus reveals a druggable ultraconserved RNA element

The human genome is dominated by noncoding sequences, most of which are poorly conserved across species. How genetic information is distributed between coding and noncoding regions remains a fundamental unresolved question. Using CRISPR saturation mutagenesis at base-pair resolution, we mapped the functional fitness landscape of the 10-kb human MYC locus with a near-PAMless, high-fidelity SpRY-Cas9. This unbiased interrogation revealed that the majority (67%) of functionally essential base-pairs in this locus are noncoding. Paradoxically, the phenotypic impact of noncoding sequences correlates inversely with evolutionary conservation, driven in part by rapidly diverging cis-regulatory DNA elements that remain functionally constrained in humans. Within this landscape, we identified an ultraconserved RNA element in the 3 untranslated region (UTR) that is indispensable for MYC-dependent cancer cells. Remarkably, steric-blocking antisense oligos targeting this RNA element selectively eliminate MYC-addicted cancer cells by suppressing MYC function without reducing MYC abundance. Mechanistically, this 3' UTR element promotes perinuclear localization of MYC mRNA and efficient nuclear import of the short-lived MYC protein, enabling its function as a nuclear transcription factor. Together, these findings highlight noncoding sequences as major carriers of functional genetic information, provide a comprehensive fitness map of the MYC locus, and uncover a therapeutically actionable RNA element that disables MYC-driven cancer.

genomics↗

bioRxiv2025

The Function of Efhd1+ Telocytes in the Synovial Lymphatic System and Inflammatory-Erosive Arthritis

Resting collecting lymphatic vessels (cLVs) sense edema in distal joints and initiate contractions via unknown mechanisms. Rheumatoid arthritis (RA) patients have lymphatic drainage deficiencies from affected joints, and defects in the synovial lymphatic system exacerbate inflammatory-erosive arthritis in animal models. To understand this, we generated Efhd1-CreERT2 and Myoc-CreERT2 mice for cell-specific genetic gain and loss of function studies. These mice were crossed with tdTomato reporter (Ai9) mice, and studies showed selective tamoxifen-induced transgene expression in CD31-/CD34+ telocyte-like cells in knee and ankle synovium, and in networks physically associated with mast cells proximal to popliteal lymphatic vessels (PLVs). Consistent with the known loss of CD31-/CD34+ telocyte in RA synovium, these cells were also decreased in TNF-tg knees and partially recovered by anti-TNF treatment. Ultrastructural and gene expression studies confirmed a distinct telocyte phenotype versus closely related fibroblasts. In vivo depletion studies in tamoxifen-treated Efhd1-CreERT2 and Myoc-CreERT2 mice crossed to diphtheria toxin alpha-floxed (DTAflox) mice demonstrated telocyte requirements for physiologic lymphatic drainage and resolution of joint inflammation and focal erosions from zymosan-induced arthritis in the knee. In vitro studies demonstrated increased sensitivity to osmotic shock and decreased motility versus fibroblasts, and telocyte potential to differentiate into myofibroblasts on stiff matrix. Collectively, these findings support a model of joint homeostasis in which osmotic pressure-sensing telocyte networks extend from the synovium into mast cells proximal to joint-draining cLVs, and telocyte loss is associated with defects in the synovial lymphatic system and increased susceptibility to joint inflammation and structural damage from arthritis. TeaserThis study discovered a unique cell type (telocytes) responsible for draining inflammation from arthritic joints.

cell biology↗

bioRxiv2025

Skin-conformal electronics for wearable electrogastrography monitoring

Electrogastrography (EGG), a non-invasive method for measuring gastric myoelectrical activity, offers valuable insights into gastrointestinal motility and functional disorders such as gastroparesis and functional dyspepsia. Despite its diagnostic potential, the clinical adoption of EGG has been limited due to its reliance on rigid electrodes and bulky instrumentation, which leads to motion artifacts and poor signal quality, and ultimately reduces patient comfort and restricting data collection to short-duration, stationary settings. To address these limitations, we present FlexEGG, a skin-conformal, flexible electronic system engineered for high-fidelity EGG monitoring in both clinical and real-world environments. The device incorporates a soft, stretchable electrode array specifically designed for the abdominal surface, utilizing a hybrid stretchable conductor composed of conductive polymer, silver nanowires (AgNWs), and polyurethane elastomer, which leads to good skin contact, signal stability, and mechanical conformability. A custom low-noise analog front-end and digital signal processing pipeline enables reliable acquisition of low-frequency, low-amplitude gastric slow waves. Additionally, FlexEGG supports simultaneous electrocardiogram (ECG) measurement, potentially facilitating integrated gut-heart axis monitoring for broader physiological assessment. In this study, we describe the design, implementation, and validation of FlexEGG in multi-channel, long-duration EGG and ECG recordings. Our findings demonstrate its potential as a wearable, non-invasive tool for continuous gastrointestinal electrophysiology monitoring, enabling new opportunities for diagnosing and managing digestive disorders in everyday settings.

bioengineering↗

bioRxiv2025

Highly Adaptive Conductive Polymer Electronics Enhance Neural Data and Learning Accuracy

Human skin, the bodys largest organ, plays a vital role in sensing and transmitting neuronal, mechanical, and biochemical signals, making it an essential non-invasive interface for health monitoring, rehabilitation, and human-machine interaction. However, aging-related changes, including thinning, increased wrinkling, dryness, and altered collagen structure, significantly impact electrical impedance, conductance, and contact stability, challenging the fidelity and consistency of bioelectronic signal acquisition. Here, we address this gap by developing "AdapSkin," an age-adaptive, skin-mimicking, bio-adhesive, and stretchable polymeric electronic skin interface that seamlessly conforms to diverse skin properties, enabling high-fidelity and high-density electrophysiological recording. The soft electrodes of AdapSkin are composed of an aqueously processed, homogeneously mixed organic nanocomposite with a conductive polymer percolation network, forming a gel-like interface that reduces modulus and enhances skin-electrode contact. The materials platform achieves extraordinary softness and electrical stretchability of up to 1200% through a double-network composite structure. AdapSkin significantly minimizes age-induced variations in interfacial impedance and signal-to-noise ratio (SNR), improving signal consistency for neuromuscular assessment, prosthetic control, and rehabilitation applications. Scalable fabrication enables the creation of large-area electrode arrays, which reduces motion artifacts, improves sEMG mapping reliability, and ensures long-term signal stability across various age groups. Machine learning analysis further demonstrates AdapSkins superior accuracy in gesture classification for elderly users, highlighting its potential to enhance prosthetic control, assistive robotics, and rehabilitation for individuals with sarcopenia and neuromuscular decline. By improving signal quality and adaptability in aging populations, AdapSkin advances fair bioelectronic interfaces, fostering more equitable and effective healthcare technologies for age-related conditions.

bioengineering↗

bioRxiv2025

Mycoelectronics: Bioprinted Living Fungal Bioelectronics for Artificial Sensation

The intelligence of the human biological system is enabled by the highly distributed sensing receptors on soft skin that can distinguish various stimulations or environmental cues, thus establishing the fundamental logic of sensing and physiological regulation or response. To replicate biological perception, two approaches have emerged: artificial nervous systems that utilize soft electronics as biomimetic receptors to convert external stimuli into frequency-encoded signals, and biohybrid solutions that integrate living cells, plants, or even live animals with electronic components to decode environmental cues for life-like sensations. However, most current biohybrid approaches for artificial sensation are based on eukaryotic cells, which suffer from slow growth, stringent culture conditions, environmental susceptibility, and short lifespans, thus limiting their integration into practical wearables or robotic sensory skins. Here, we introduce fungi-based printable "Mycoelectronics", which are created by additive bioprinting of living fungal mycelium networks onto stretchable electronics, as a practical living thermo-responsive sensory platform. This Mycoelectronics approach leverages fungis capacity for rapid biological responsiveness, cultivability with exponential growth, stability and self-healing in ambient conditions, bioprintability for scalable manufacturing, and mechanical flexibility for seamless integration with soft electronics. Critically, we discovered that the thermal responsiveness of the fungal network arises from intrinsic cellular processes--specifically, heat-induced vacuole remodeling and fusion, which modulate ionic transport and thus the electrical conductivity of the mycelial cells and networks, enabling a rapid temperature response. By bridging the gap between cell biology and soft electronics, the Mycoelectronics device with a living mycelium network functions as a thermal sensation system with rapid response and intrinsic self-healing properties, autonomously restoring sensing capabilities after damage or autonomously establishing sensor pathways in hard-to-reach locations. Furthermore, by integrating fungal thermal sensing with electronic circuits, we established a hybrid bioelectronic reflex arc that can actuate muscles and initiate diverse actions, suggesting promising applications in future neurorobotics and neuroprosthetics.

bioengineering↗

bioRxiv2025

Using lightsheet microscopy to investigate the initial lymphatic network in the murine knee joints

Introduction. Lymphatic vasculature in mouse joints is difficult to study due to its vast anatomical variation. We reported increased lymphatic capillaries in post-traumatic OA (PTOA) murine joint based on 2D immunostaining. However, a gap of knowledge with this approach is that histology highly subjected to histological sampling, which might not be appropriate for a highly variable system such as the lymphatic vasculature. We hypothesize that using lightsheet microscopy would reveal the detailed structure of the initial lymphatic network. Methods. We established lightsheet imaging protocol and four quantifiable outcome parameters for visualizing and analyzing the initial lymphatic network in young C57/B6 wild type mouse knees. Lymphatic vessels were identified by staining samples with lymphatic endothelial marker LYVE1. We validated our lightsheet imaging protocol in mouse knee joints following PTOA surgery and knee joints received sham operation. Results. We used the histological landmarks of growth plates and menisci shape for consistent data collection for the 3D reconstruction of initial lymphatic network. Comparing to sham joints, PTOA joints have less mean branches length (58.91{+/-} 6.50 vs. 146.29 {+/-} 2.48 m in sham, p<0.0001), and mean branch diameter (12.25{+/-} 0.80] vs. 28.51 {+/-} 4.99 m in sham, p=0.0051), but higher total branching points (378{+/-} 239 vs. 69 {+/-} 17 m in sham, p=0.020), and total initial lymphatic network volume (51247{+/-} 14239 vs. 1019289 {+/-} 544458 m3 in sham, p=0.037). Conclusion. Lightsheet imaging of murine knee joints is a powerful and promising tool to study the joint lymphatic system and arthritis. Similar to previous report, the PTOA joint has increased branching with smaller and shorter branches.

cell biology↗

bioRxiv2025

Deep Sound Synthesis Reveals Novel Category-Defining Sound Features in the Human Auditory Cortex

The human auditory system extracts meaning from the environment by transforming acoustic input signals into semantic categories. Specific acoustic features give rise to distinct categorical percepts, such as speech or music, and to spatially distinct preferential responses in the auditory cortex. These responses contain category-relevant information, yet their representational level and role within the acoustic-to-semantic transformation process remain unclear. We combined neuroimaging, a deep neural network, a brain-based sound synthesis, and psychophysics to identify the sound features that are internally represented in the speech- and music-selective human auditory cortex and test their functional role in sound categorization. We found that the synthetized sounds exhibit unnatural features distinct from those normally associated with speech and music, yet they elicit categorical cortical and behavioral responses resembling those of natural speech and music. Our findings provide new insights into the fundamental sound features underlying speech and music categorization in the human auditory cortex.

neuroscience↗

bioRxiv2024

scAGCI: an anchor graph-based method for cell clustering from integrated scRNA-seq and scATAC-seq data

Cell clustering plays a crucial role in the analysis of single-cell multi-omics research. Despite many methods for multi-omics integrated clustering, challenges such as noise, data sparsity, and biointerpretability analysis hider effective clustering. Recent studies have demonstrated that anchor graph learning clustering in the multiview graph domain can help alleviate sparsity and high noise, reducing runtime costs. However, addressing the heterogeneity and high noise levels in multi-omics data is crucial for obtaining a more representative anchor graph. Furthermore, the existing methods often directly obtain surface information from multi-omics for clustering purposes, neglecting the mining and utilization of higher-order correlations among different features within shared information. In response to these challenges, we propose scAGCI, a cell clustering method based on anchor graphs that integrates both scRNA-seq and scATAC-seq data. Our method captures specific and shared anchor graphs representing the properties of omics data in the process of dynamic anchor unification, and mines high-order shared information to complete the omics representation. Subsequently, clustering results are obtained by integrating the specific and shared omics representation. Extensive experiments show that our method not only outperforms 13 state-of-the-art methods in terms of clustering metrics and running time, but also that the completed omics retains the biological meaning of the original omics.

bioinformatics↗

bioRxiv2024

Indiv-Brain: Individualized Brain Network Partition Learned from Individual fMRI Data using Deep Clustering with Vertex-level Attention

Individualized functional network partitioning is increasingly critical in elucidating individual differences in cognition, development, and behavior. The previous studies grouped brain regions that were pre-defined by common brain parcellations into individualized brain networks. The employment of common brain region parcellations ignores the individual variations in brain structure and reduces the spatial resolution of the results. Moreover, some studies trained models on a group of subjects to guide individual network partitioning. These methods largely depend on the sample size and encounter challenges in the case of limited subject data. In this paper, we propose Indiv-Brain which automatically partition brain vertices into different brain networks based on individual fMRI data without any prior brain parcellation. The Indiv-Brain consists of three sequential modules: stacked denoising autoencoder (SDAE) for mapping the raw fMRI data to a latent embedding space, masked vertex modeling (MVM) for learning attention-enhanced representations of brain vertices, and deep embedding clustering with spatial attention (DEC-A) for unsupervised clustering on the learned vertex representations. The experiments on Human Connectome Project (HCP) demonstrate that the accuracy of Indiv-Brain outperforms existing methods. We compared the model with methods like SDAE, DEC, IDEC, and k-means. For the results of 8 subjects, the accuracy of Indiv-Brain was consistently the highest, averaging 6.65 percentage points higher than the IDEC method. To the best of our knowledge, this is the first study to obtain individualized brain network partition based on individual fMRI data with deep learning models. Our study provides a novel insight into understanding individualized brain networks, especially suitable for special patients.

neuroscience↗

bioRxiv2024

Methemoglobin aggregation is modulated by the anti-sickling drug voxelotor

Sickle cell disease is caused by a mutation in the beta subunit of hemoglobin (HbSS) that drives Hb fiber formation when the protein is in the deoxygenated (tense, T) state. The drug voxelotor was recently approved to treat sickle cell disease by preventing HbSS fiber formation. Voxelotor acts as an allosteric inhibitor of polymerization by maintaining the HbSS protein in the relaxed (R) conformation, limiting polymerization of T-state fibers. Normal blood cells contain small amounts of natural Hb fibers and a few percent of the Fe3+ ferric form, metHb, incapable of binding oxygen. Although the drug Voxelotor is now in use, the effect of the drug on the oxidized metHb state has not been reported. Here we assessed the influence of voxelotor on normal human metHb. We compared the aggregation of metHb at two pH values (5.5 and 7.1). MetHb is known to form organized fiber structures at or below pH 5.5. We find that voxelotor significantly enhances fiber formation of metHb R-state at pH 5.5, consistent with the mode of action for this drug in maintaining the Hb R conformation. The opposite effect is observed at physiological pH values. Voxelotor significantly decreases the rate of metHb aggregate formation at pH 7.1 but did not affect protein stability. Notably, drug binding drives metHb into novel spherical particles with a morphology never seen before for Hb. The formation of these particles should be considered in patients being treated for sickle cell disease with voxelotor. WHY IT MATTERSVoxelotor is an FDA-approved drug for sickle cell anemia, known to prevent hemoglobin fiber formation. Here, we investigate its effect on methemoglobin, the form of hemoglobin in which iron takes on the ferric Fe3+ state. Our study examines voxelotors impact on methemoglobin aggregation and stability. At pH 7.1, we found voxelotor to have an effect on methemoglobin solubility as evidenced by the formation of novel methemoglobin spherical structures. We observe that voxelotor significantly increases methemoglobin fiber formation at pH 5.5 but, notably, reduces methemoglobin aggregation at physiological pH levels. Minimal impact on methemoglobin thermodynamic stability is noted. These findings suggest voxelotors potential therapeutic efficacy for various hemoglobinopathies, including conditions characterized by Heinz body formation.

biophysics↗

bioRxiv2024

The effects of 17α-estradiol treatment on endocrine system revealed by single-nucleus transcriptomic sequencing of hypothalamus

In this study, we investigated 17-estradiols role in lifespan extension from long-term administration. Pooled hypothalami from aged male Norway brown rats treated with 17-estradiol (O.T), aged male controls (O), and young male controls (Y) underwent single-nucleus transcriptomic sequencing (snRNA-seq). To evaluate the effects of 17-estradiol on aging neurons, supervised clustering of neurons based on neuropeptides and their receptors were used to evaluate the responses of each neuron subtype during aging and after 17-estradiol treatment. The elevated cellular metabolism, stress and decreased expression levels of pathways involved in synapse formation in neurons initiated by aging were significantly attenuated by 17-estradiol. Assessment of changes in neuron populations showed that neurons related to food intake, reproduction, blood pressure, stress response, and electrolyte balance were sensitive to 17-estradiol treatment. 17-estradiol treatment not only increased serum Oxytocin (Oxt), but also heightened the activity of hypothalamic-pituitary-gonadal (HPG) axis, as evidenced by significantly elevated levels of plasma Gnrh, total testosterone, and decreased estradiol. Elevated Gnrh1 was confirmed to be one of the causal effects mediating the role of 17-estradiol in energy homeostasis, neural synapse, and stress response. Notably, Crh neurons exhibited prominent stressed phenotype in O.T, distinct to appetite-stimulating neurons Agrp and Ghrl. Therefore, the HPG axis and energy metabolism may be key targets of 17-estradiol in male hypothalamus. Additionally, supervised clustering of neurons was shown to be a useful method for assessing treatment responses and cellular perturbation among different neuron subtypes in the hypothalamus.

neuroscience↗

bioRxiv2024

Genome sequencing of 'Fuji' apple clonal varieties reveals evolutionary history and genetic mechanism of the spur-type morphology

Somatic variations arising during asexual reproduction can lead to the emergence of bud sports exhibiting advantageous traits, forming the basis for bud sport breeding in perennial plants. Here, we report a near-complete, fully phased genome assembly of Fuji apple, enabling comprehensive identification of somatic variants across 74 clonally propagated Fuji varieties. Phylogenetic analysis of Fuji sport varieties indicates that the emergence of spur-type and early maturation traits results from multiple independent formation events. A number of putative functional somatic variants are identified, including one spur-type specific deletion located in the promoter of the TCP transcription factor gene MdTCP11. DNA methylation level of the deletion-associated miniature inverted-repeat transposable element is lower in the spur-type varieties compared to the standard-type varieties, while the expression of MdTCP11 is significantly higher. Overexpression of MdTCP11 in apple decreases the plant height, highlighting its important role in the development of spur-type apple varieties. This study sheds light on the 80-year cloning history of Fuji and provides valuable candidate causative mutations for apple breeding.

plant biology↗