Biology subjects

Xu, G.

Publications and source records attributed to Xu, G..

At least 19 recordsLinked to original sources

bioRxiv2026

HIV-1 prime-boost vaccination shapes distinct clonal trajectories and memory precursor states of Env- and Gag-specific T cells

Despite decades of HIV-1 vaccine development, the clonal and cellular determinants of durable vaccine-induced T cell memory remain incompletely understood. Here, we combined antigen-specific T cell receptor (TCR) identification, longitudinal TCR sequencing, and single-cell multi-omics to characterize Env- and Gag-specific memory precursor T cells elicited by the HIV Vaccine Trials Network (HVTN) 505 DNA prime-recombinant adenovirus serotype 5 (rAd5) boost (DNA/rAd5) vaccine regimen. We developed a generalizable high-throughput approach to identify HIV-1 Env- and Gag-specific TCRs and found distinct patterns of clonal expansion, persistence, and contribution to memory between Env- and Gag-specific CD8 T cell responses. The DNA prime and rAd5 boost differentially shaped these repertoires, with rAd5-induced clones contributing proportionally more to the Gag-specific than to the Env-specific memory precursor compartment. Single-cell immune profiling further revealed distinct memory precursor states, with Env-specific responses enriched for GZMBPRF1 cytotoxic effector-memory (EM) CD8 T cells and Gag-specific responses containing a larger cycling/proliferative population. Together, these findings demonstrate that heterologous DNA/rAd5 vaccination generates antigen-specific CD8 T cell memory with distinct clonal trajectories and cellular programs, providing new insights into how vaccine platform and antigen-specificity shape the durability and functional properties of HIV-1 specific cellular immunity.

immunology↗

bioRxiv2026

AB-Free Kava and its Kavalactones Suppress Cigarette Smoke- and Lipopolysaccharide-Induced Lung Inflammation: Efficacy and Mechanisms

Cigarette smoke-induced lung inflammation is a central driver of pulmonary diseases. The limited efficacy of current anti-inflammatory agents underscores the need for structurally novel therapeutics with distinct mechanisms. We recently demonstrated that AB-free kava, a flavokavains A/B-depleted formulation from Piper methysticum containing six major kavalactones, effectively suppresses cigarette smoke-induced lung inflammation in mice. This study aims to identify the bioactive constituent(s) and elucidate underlying mechanisms. These kavalactones revealed a clear structure-activity relationship in suppressing lipopolysaccharide (LPS)-stimulated prostaglandin E2 (PGE2) production in macrophages with desmethoxyyangonin (DMY) as the most potent kavalactone whereas dihydrokavain (DHK, a structurally similar analog) with minimal activity. DMY also effectively reduced LPS-induced interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-) production while DHK was ineffective. Mechanistically, DMY, but not DHK, attenuated COX-2 induction and reduced phosphorylation of cAMP response element-binding protein (CREB). Pharmacological inhibition of protein kinase A (PKA) similarly reduced p-CREB, COX-2 and PGE2, supporting a PKA-dependent CREB/COX-2 signaling in mediating PGE2 suppression while these effects were independent of nuclear factor kappa B (NF-{kappa}B) and activator protein 1 (AP-1) signaling. Similar results were observed for DMY and DHK in attenuating cigarette smoke condensate-induced proinflammatory pathways and PGE2 production. Consistently, DMY demonstrated significant in vivo efficacy in suppressing cigarette smoke-induced lung inflammation while DHK was not effective. Interestingly, dihydromethysticin (DHM) demonstrated the greatest in vivo anti-inflammatory efficacy, although it only exhibited moderate in vitro potency, likely due to its superior bioavailability over DMY. Concordantly, cigarette smoke exposure elevated p-CREB and COX-2 expressions in mouse lungs, which were attenuated by AB-free kava and its bioactive kavalactones with the extent of suppression correlating with their in vivo anti-inflammatory efficacy. DHM effectively suppressed LPS-induced neutrophil accumulation in mouse lungs as well. Collectively, these studies identify bioactive kavalactones in AB-free kava that suppress cigarette smoke- and LPS-induced lung inflammation through the modulation of the PKA/CREB/COX-2 signaling axis, providing a foundation for developing structurally distinct anti-inflammatory agents, particularly targeting smoke-induced inflammation and associated pulmonary diseases.

immunology↗

bioRxiv2026

Cross-Species Comparison of Topologically Associating Domains (TADs) in Cereals Reveals Their Role in Genome Stability During Evolution

Topologically associating domains (TADs) are essential structural and functional modules of the genome that play a crucial role in regulating gene expression. In this study, we systematically investigated the conservation and evolution of TADs in five closely related crops, including maize, sorghum, coix, foxtail millet and broomcorn millet. Our results show that 74% of TAD boundaries are conserved between two inbred maize lines, B73 and Mo17, and that approximately 50% or more of TAD boundaries are conserved across different crop species. TAD number remains relatively stable in the face of changes in genome size. However, the length of TADs varies depending on genome size. Furthermore, we found that large-scale transposable element expansion leads to TAD expansion, while chromosomal inversions lead to TAD fusion and the formation of new TAD boundaries. Frequent chromatin interactions between subgenome chromosomes occur after whole-genome duplication. Moreover, we also found that crossovers are enriched at TAD boundaries in maize, indicating the importance of TADs as a fundamental unit during species evolution. Overall, our study provides insights into the conservation and evolution of TADs in crop genomes and their roles in genome organization and function.

plant biology↗

bioRxiv2026

PFM: perturbed flow matching for structure-based drug design

Generating 3D molecules that bind to specific protein targets via generative models has shown great promise in structure-based drug design. Recently, diffusion-based methods have achieved promising results, but their reliance on high sampling steps poses risks of slowing the drug discovery process due to increased time and computational costs. In this work, we propose a novel method named Perturbed Flow Matching (PFM), which significantly reduces sampling steps by leveraging a Flow Matching framework. PFM introduces a unique perturbed conditional probability path design that incorporates pocket binding site information and atom type-coordinate coupled information to enhance molecular generation performance. Experiments on CrossDocked2020 dataset demonstrate that PFM generates molecules with competitive 3D structures and state-of-the-art (SOTA) binding affinities towards the protein targets, achieving an Avg. of -7.12. Additionally, PFM accelerates the generation of valid molecules by a factor of 21.3, while demonstrating potential for further improvement. The code is available at https://github.com/kurisu92725/PFM.

bioinformatics↗

bioRxiv2026

Recognition Mechanism of Serotonin by a G-Quadruplex-Duplex Hybrid Aptamer

Serotonin is a key neurotransmitter, and aptamer-based tools using the 44-nt Apt44 have been successfully developed for its in vitro and in vivo detection. Nevertheless, the structural basis of recognition by this aptamer remains unclear. Here we report high-resolution NMR structures of Apt38, a 6-nt truncated variant in the third loop of Apt44, in free and serotonin-bound states. Both structures reveal a two-layered antiparallel chair-type G-quadruplex core with three edgewise loops and a terminal duplex, forming a G-quadruplex-duplex hybrid structure. Serotonin binds at the G-quadruplex-duplex junction, stabilized by stacking, electrostatic attraction, hydrogen bonding, and hydrophobic contacts. Apt38 is preorganized for binding, whereas the longer third loop of Apt44 introduces conformational dynamics into the G-quadruplex scaffold, which enables a pronounced binding-triggered conformational switch in PBS buffer, explaining its sensing mechanism. Our work reveals the recognition and sensing mechanism of the serotonin aptamer and provides a framework for aptamer design in serotonin biosensing.

biophysics↗

bioRxiv2026

Circular RNA aptamers act as superb sub-stoichiometric chaperones to prevent cytosolic TDP-43 condensation

Pathological protein misfolding and aggregation underlie many devastating human diseases, yet strategies to selectively neutralize aggregation-prone protein states without perturbing their normal functions remain limited. Here we identify loosely structured circular RNA (cRNA) aptamers, circT3 and its minimized 116-nt variant circT3-M3, as superb sub-stoichiometric RNA chaperones that suppress pathological assembly of TAR DNA-binding protein 43 (TDP-43), a defining feature of amyotrophic lateral sclerosis and frontotemporal dementia, in vitro and in cells. Rather than acting through simple stoichiometric sequestration, these cRNA aptamers engage TDP-43 transiently and iteratively through functionally and pathologically important residues in the RRM1 domain. Such interaction enables a single cRNA aptamer to promote rapid and multiple RRM1-dependent homomeric assembly, thereby stabilizing TDP-43 in a soluble oligomeric state to outcompete the C-terminal prion-like domain-driven condensation and supersaturation. Together, our findings establish cRNA aptamers as highly efficient subcellular RNA chaperones with exceptionally potent low-dose activity and highlight their promise as next-generation RNA therapeutics for certain protein-aggregation disorders.

molecular biology↗

bioRxiv2026

The CCCH-type zinc-finger PfMD3 promotes translation for malaria parasite transmission

Sexual maturation and fertility of the malaria causing parasite, Plasmodium spp., is critical to transmission between hosts. This developmental process involves an intricate gene expression regulatory network that drives gametocyte commitment, development, and the production of male and female gametes. Here, we characterized the role of the CCCH-type zinc-finger protein Plasmodium falciparum Male Development 3 (PfMD3) in the formation of gametes. Genetic disruption of PfMD3 revealed a male fertility defect that decreased infectivity to mosquitoes. Molecular characterization of PfMD3 revealed its binding to mRNA transcripts associated with male gamete development through a specific RNA sequence. Gametocyte proteins encoded by these PfMD3-bound transcripts decreased significantly in PfMD3 knockout parasites, suggesting that PfMD3 impacts translation. In addition to RNA-binding, PfMD3 also interacts with proteins involved in mRNA processing and nuclear export that influence translational regulation. This study establishes PfMD3 as an RNA-binding protein that impacts lineage-specific translation and male gamete fertility.

molecular biology↗

bioRxiv2026

ProtmRNA: Cross-Modal Knowledge Transfer from Proteins to Messenger RNA

MotivationAccording to the central dogma of molecular biology, messenger RNA (mRNA) sequences are directly translated into amino acid sequences, positioning mRNA as the fundamental intermediary between genetic information and functional proteins. This natural correspondence suggests that mRNA sequence analysis could greatly benefit from the rich evolutionary and functional representations learned by large-scale protein language models. ResultsProtmRNA repurposes the pre-trained ESM-2 protein language model for mRNA sequence processing via cross-modal transfer learning. Evaluated on mRNA- and protein-related datasets, along with eight additional benchmarks compiled in this study, ProtmRNA achieves performance comparable or superior to state-of-the-art mRNA language models while using less than half the pre-training computational resources. This work establishes the potential of cross-modal transfer learning between biological sequences by demonstrating that protein-derived knowledge can be efficiently transferred to mRNA, offering a resource-efficient paradigm for advancing mRNA sequence understanding. Availability and ImplementationThe pre-trained ProtmRNA model and the eight CDS-region regression benchmarks curated in this study are publicly available at https://github.com/pesenteur/ProtmRNA.

bioinformatics↗

bioRxiv2026

Sequence-Defined Digital Bottlebrush Polymers for Programmable Oligonucleotide Delivery

Oligonucleotide therapeutics hold transformative potential, yet their clinical translation is hindered by delivery barriers, including rapid renal/hepatic clearance and poor organ specificity. Bottlebrush polymers conjugates have emerged as a promising vector to address these limitations, but conventional architectures with uniform backbones can only achieve an unmodifiable, rigid biodistribution profile. Here, we report a library of sequence-defined "digital" bottlebrush polymers, precisely engineered with controlled placements of chemical motifs that modify physiochemical properties - including lipids, cholesterol, and cationic groups - along a polyphosphodiester backbone. Systematic evaluation of the digital bottlebrush polymer library reveals distinct structure-property relationships and enables organ-biased systemic delivery to several traditionally difficult-to-reach tissues, including muscle and skin. In a mouse model of rheumatoid arthritis, a single dose of a spleen-homing polymer-conjugated antisense oligonucleotide targeting TNF- achieves potent knockdown and drives full functional recovery. These findings establish a versatile design framework for tailoring bottlebrush polymers to specific therapeutic applications.

bioengineering↗

bioRxiv2026

Nitrogen adaptation and phenotypic transitions from wild to improved sorghum

Crop domestication and subsequent improvement under modern agronomic conditions have altered the nitrogen (N) regimes experienced by crops, yet how selection has reshaped the genetic architecture of phenotypic responses to N availability remains poorly understood. Here, we integrated population genomic analyses of n = 289 sorghum accessions spanning multiple stages of domestication and improvement with N-response (NR) trait-associated variants identified through genome-wide association studies (GWAS) of phenotypic data collected under two contrasting N conditions in n = 347 diverse sorghum accessions. Unlike maize and sunflower, sorghum showed a reduced deleterious burden both genome-wide and within historically balanced and recently selected regions following domestication and improvement. Additionally, we identified 470 trait-associated loci (TALs), including 273 associated with NR traits. The effects of these NR-associated loci showed no apparent bias toward derived alleles, suggesting that selection on NR traits in sorghum has not been sufficiently strong or directional to consistently overcome genetic drift. Together, these results reveal distinct patterns of selection in sorghum and provide promising genetic targets for improving N-use efficiency in sustainable agricultural systems.

genomics↗

bioRxiv2026

Wnt/β-catenin signaling restrains developmental beiging and imprints long-term energy expenditure

Beige adipocytes that emerge during the peri-weaning period support sympathetic nervous system (SNS)-independent thermogenesis, yet the mechanisms governing this spontaneous beiging remain unclear. Here, by integrating transcriptomic profiling with adipocyte-targeted Ctnnb1 deletion in mice, we identify the canonical Wnt signaling as an endogenous brake on developmental beige thermogenesis. Peri-weaning inguinal fat from adipocyte Ctnnb1 knockout mice exhibits enhanced beige adipocyte biogenesis, with increased thermogenesis-related gene expression and mitochondrial oxidative capacity, which programs durable activation of adaptive thermogenesis and augmented whole-body energy expenditure into adulthood. Mechanistically, suppression of Wnt/{beta}-catenin signaling induces a non-canonical Wnt5a-Ca2-AMPK axis that promotes triglyceride lipolysis and subsequent PPAR-driven fatty acid oxidation, thereby fueling mitochondrial respiration. Genetic or pharmacological disruption of this axis blunts thermogenic responses induced by {beta}-catenin inhibition in both murine and human subcutaneous adipocytes, indicating that Wnt5a-Ca2-AMPK axis is required for the cell-autonomous activation of beige fat. These results reveal Wnt/{beta}-catenin signaling as a developmental constraint on beige adipocyte formation and suggest an SNS-independent route to sustainably raise energy expenditure and improve metabolic health.

physiology↗

bioRxiv2026

Indazolone-Based Molecular Glue Degraders as a Tunable Platform for Reprogramming Cereblon Substrate Specificity

Molecular glue degraders (MGDs) represent a transformative modality in drug discovery, with the cereblon (CRBN)-MGD axis offering a strategic gateway to systematically address the historically undruggable proteome. However, the limited chemical diversity of existing CRBN-mediated MGDs has constrained the full exploration of the degradable landscape. Here, we introduce an innovative indazolone-based platform that extends beyond canonical isoindolinone-glutarimide scaffolds, significantly expanding the accessible chemical space for CRBN modulation. Guided by mechanistic insights into CRBN-MGD complex conformational plasticity, we rationally designed indazolone architectures as novel CRBN ligands, developing diverse MGDs with potent ligase binding and exceptional substrate programmability. This platform enables fine-tuned control over neo-substrate recognition, supporting diverse degradation profiles ranging from the broad targeting of critical proteins (IKZF1/3, ZFP91, and LIMD1) to the exquisitely selective degradation of CK1 and IKZF2. Beyond expanding the chemical landscape for intractable targets, our indazolone-based MGDs exhibit favorable pharmacokinetic properties, offering robust promise for therapeutic development. Collectively, the remarkable tunability and exceptional neo-substrate programmability of the indazolone-based platform provide a highly transformative blueprint for next-generation MGD discovery, enabling systematic exploration of the vast CRBN-accessible proteome. Furthermore, as superior CRBN ligands, this platform holds immense potential for PROTAC discovery to systematically address previously intractable targets.

biochemistry↗

bioRxiv2026

Estradiol modulates neuronal network hyperexcitability in select NDD risk genes

Sex hormone signaling during neurodevelopment may act as a modulator of risk for neurodevelopmental disorders (NDDs), including autism spectrum disorders (ASDs). By conducting a systematic and multi-modal evaluation of estradiol effects across loss-of-function deletions in 36 functionally diverse, large-effect ASD/NDD genes in human induced pluripotent stem cell-derived neurons and larval zebrafish, we uncover convergent and divergent gene-by-estradiol interactions at the transcriptomic, circuit, and behavioral levels. Whereas estradiol partially ameliorates dysregulated expression signatures across all ASD/NDD gene knockouts examined, it selectively and rapidly dampens network hyperexcitability phenotypes in only a subset of ASD/NDD gene knockouts. Two genes, ASH1L and SCN2A, are particularly responsive to estradiol treatment, with dramatic rescue of molecular and cellular effects in human knockout neurons, coupled with behavioral phenotypes in larval zebrafish mutants. The seven most estradiol responsive genes show enhanced protein-protein interaction network connectivity, strong co-expression in specific postnatal time periods, and enrichment in upper-layer mature excitatory neurons. Altogether, we describe distinct estradiol rescue in different modalities, elucidating shared transcriptomic effects as well as gene-specific cellular and behavioral rescue in the context of loss of function mutations of select ASD/NDD genes.

genomics↗

bioRxiv2026

Molecular architecture of the tumor microenvironment caused by BRCA1 and BRCA2 somatic mutations in lung adenocarcinoma

ObjectivesHomologous recombination repair (HRR) deficiency is associated with improved immunotherapy responses in non-small cell lung cancer (NSCLC) patients. The HRR genes BRCA1/2 are key regulators of DNA repair, yet their impact on the tumor microenvironment (TME) in lung adenocarcinoma (LUAD) remains unclear. MethodsUsing single-cell sequencing and multi-omics data, we characterized BRCA1/2 mutation-associated transcriptional programs, immune cell composition, and functional alterations in T cells, investigating the molecular and immune architecture of BRCA-mutant LUAD patients. ResultsBRCA1/2 mutations were associated with increased genomic instability and poor prognosis in LUAD patients, but predicted better clinical outcomes following immune checkpoint blockade (ICB) treatment. BRCA1 mutations correlated with an upregulated type I IFN/IFN-{gamma} signature and CD8+ T cell activation. BRCA2 mutations were associated with alveolar/stress/inflammatory responses and enhanced MHC-II antigen presentation, linked to CD4+ T cell differentiation. Both alterations coincided with reduced CD28 co-stimulation and CTL activity, hinting of immune evasion. We identified two tissue-resident memory T cell (Trm) subsets as predictors of clinical outcomes and ICB response. BRCA1 mutations were associated with CD8+ Trm expansion, whereas BRCA2 mutations linked to tumor CD4+ Trm expansion and peripheral T/NK cell cytotoxicity. Furthermore, a cancer-promoting program activated by BRCA1 mutation was vulnerable to histone deacetylase inhibitors, which inhibited LUAD tumor growth. ConclusionsThis study provides a preliminary characterization of the BRCA-mutant TME in LUAD patients, revealing distinct transcriptional and immune patterns that highlight differences in BRCA1/2-associated molecular architecture and offer a framework for improving therapy efficacy in LUAD.

cancer biology↗

bioRxiv2026

Detecting visual deficits in retinal degeneration mice using photoacoustic tomography

We established a photoacoustic tomography and ultrasound imaging system capable of resolving visually evoked hemodynamic responses in the cortical and subcortical visual regions of the brains of freely behaving mice. By searching for anatomical landmarks in the US imaging planes, we can locate brain regions of interest and continuously record HR in these regions. The system was examined in retinal degeneration mice using a 60-second protocol and in Claudin 5 knockdown mice and mice with vision deficits using a 100-minute-long vision research protocol. We found that: 1) visually evoked HR amplitudes increase as visual stimulation intensity increases in both scotopic and photopic conditions; and 2) HR amplitudes increase during the light adaptation time course.

bioengineering↗

bioRxiv2026

Dual regulation of the receptor-like kinase BIR1 involves site-directed transcript cleavage and 5-leader-mediated translational control

In Arabidopsis, receptor-like kinase BRASSINOSTEROID INSENSITIVE1-ASSOCIATED RECEPTOR KINASE 1 (BAK1)-INTERACTING RECEPTOR-LIKE KINASE 1 (BIR1) is a negative regulator of plant immunity and cell death. BIR1 was earlier described as a target of epigenetic and post-transcriptional silencing. Degradome analysis mapped predominant mRNA cleavage sites at the 5-untranslated leader region (site A) and the protein-coding sequence (sites B and C). Here, we identified another cleavage site (D) within the BIR1 coding region and investigated the contribution of site-directed mRNA cleavage to BIR1 regulation. Mutations at B, C, and D sites enhanced mRNA stability by impairing transcript cleavage, resulting in increased BIR1 mRNA and protein accumulation. This regulation is disrupted in RNA silencing mutants, supporting a model of cis-directed small interfering RNA (siRNA)-mediated degradation. Cleavage events are highly localized, occurring at a limited number of sites that involve only a few siRNAs. Furthermore, our data reveal a repressive role for the 5-leader in regulating BIR1 translation, potentially mediated by upstream open reading frames (uORFs) and a long non-coding RNA (lncRNA) derived from the natural antisense At4g39838 locus. This lncRNA is complementary to a TCA-rich repeat region encompassing cleavage site A, which may serve as a putative binding site. Together, these findings reveal a multilayered regulatory mechanism that integrates sRNA-mediated cleavage with translational control, with broader implications for the fine-tuning of stress-responsive gene expression during infection.

plant biology↗

bioRxiv2026

Evolutionary history of Jamestown Canyon virus disentangles complex multi-vector ecology

Jamestown Canyon virus (JCV) is a re-emerging mosquito-borne virus of increasing concern in North America. It has been historically understudied, leading to significant gaps in our understanding of its evolutionary history, ecological maintenance, and transmission dynamics. Here, we generated 658 whole-genome JCV sequences from the Northeast United States, including 84% (500/597) of all JCV-positive mosquitoes detected in Connecticut from 1997-2022. Then we applied phylodynamic methods to demonstrate how mosquito phenology and host interaction structure the persistence and spread of JCV. Our phylogenetic analyses estimate that JCV was introduced in the Northeast by at least the early 1700s and the primary introductions of lineages A and B into Connecticut occurred during the mid-1800s to mid-1900s. Further, we estimate that JCV evolves at a rate of [~]3 x 10-5 s/s/y, making it one of the slowest evolving known RNA viruses, because the virus spends [~]10 months per year in evolutionary stasis while over-wintering in mosquito eggs. To investigate ecological drivers of JCV spread in Connecticut, we paired discrete trait and continuous phylogeographic reconstructions with mosquito surveillance data. We estimate that JCV has a low diffusion rate of [~]30-60 km2/year, which is more similar to slow-moving tick-borne viruses than other mosquito-borne viruses. We found that univoltine Aedes mosquitoes were likely to maintain the virus across years through overwintering in eggs, accounting for its slow evolution and dispersal, while multivoltine mosquitoes contribute to periodic bursts of spatial diffusion and amplification within seasons. By characterizing seasonal dynamics of JCV, we demonstrate the utility of dense sequencing and phylodynamics to disentangle complex transmission cycles, offering a framework to rapidly advance our evolutionary and ecological knowledge of understudied viruses.

ecology↗

bioRxiv2026

The non-coding facet of Pink1 mRNA regulates mitochondria homeostasis

Coding and non-coding RNAs have traditionally been viewed as functionally distinct entities. Here, we found that the down-regulation of Pink1 due to Tet2 knockout (KO) in muscle cells resulted in mitochondria dysfunction and muscle fatigue. Surprisingly, both Pink1 mRNA alone and untranslatable ATG-deficient Pink1 RNA were sufficient to rescue the mitochondria defects in Tet2 KO cells. PINK1 protein was fast degraded shortly after translation and dispensable for functions of Pink1 mRNA in muscle cells. Moreover, a portion of Pink1 mRNA was located in mitochondria and interacted directly with mitochondria inner membrane located protein YME1L1, promoting its proteolytic cleavage of Opa1, a master regulator of mitochondria fusion, to generate the mature protein form. These findings uncovered a bona fide non-coding role for a canonical mRNA, suggesting that translation independent functions could be present in mRNAs with coding potentials, blurring the conventional dichotomy between coding and non-coding RNAs.

cell biology↗