Biology subjects

Niu, S.

Publications and source records attributed to Niu, S..

16 recordsLinked to original sources

bioRxiv2026

Dynamic architecture of the Rixosome reveals mechanism of activation and ITS2 processing

Eukaryotic ribosome assembly requires the coordinated processing and extensive remodeling of pre-rRNAs. During late nuclear maturation of the 60S subunit, sequential removal of the internal transcribed spacer 2 (ITS2) is initiated by endonucleolytic cleavage at site C2 by the conserved Las1 nuclease. Las1 acts together with the kinase Grc3 and the Rix1 complex to form the Rixosome, which also functions in transcriptional regulation. However, the assembly of the Rixosome, its recruitment to pre-ribosomes, and its activation for ITS2 cleavage remain unclear. Here, we present cryo-EM structures of the human LAS1 complex, two structures of the isolated Rixosome and nine transition states of Rix1-bound pre-60S particles from Schizosaccharomyces pombe. These structures reveal a dynamic Rixosome architecture in which the heterotetrameric Las1 complex engages one or two copies of the Rix1 complex. Rix1 binding is highly flexible in the human Rixosome but rigid in the yeast complex. The isolated yeast Rixosome remains inactive, but binding to the pre-60S particle triggers a structural rearrangement that allows for substrate engagement and activation of the nuclease. Together, our results define the dynamic architecture of the Rixosome and provide a structural framework for ITS2 processing during nuclear maturation of the eukaryotic 60S ribosomal subunit.

biochemistry↗

bioRxiv2026

Transcriptomic analysis of cecal mucosal immunity in SPF White Leghorn chicks infected with precocious and parent strains of Eimeria tenella

Eimeria tenella (E. tenella) preferentially invades the cecum of young chickens and causes enormous economic losses to the global poultry industry. In this study, chick infection models of virulent parent strain and precocious attenuated line were established with schizogony (2 dpi) and gametogony (6 dpi) as two critical sampling time points. Combined with pathogenicity detection, transcriptome sequencing, mucosal immune index measurement and homologous challenge protection assays, we systematically deciphered the differential molecular mechanisms underlying pathogenicity and immune regulation between the two strains. Pathogenicity results showed that increased infection dosages suppressed weight gain and aggravated bloody diarrhea and oocyst shedding in both strains. In particular, infection with 1 x 105 sporulated oocysts of the parent strain caused massive chick mortality, while the precocious line exhibited markedly lower virulence. Transcriptomic data revealed that gametogony (6 dpi) represented the peak of host immune response. The parent strain persistently overactivated the NF- {kappa}B - mediated positive feedback cascade of coagulation and complement as well as ECM remodeling, triggering steroid metabolic disorder and antioxidant exhaustion, which ultimately induced severe hemorrhagic necrosis of the cecum. By contrast, the precocious line specifically activated the PPAR - {gamma} signaling pathway to negatively restrain excessive inflammation, accompanied by enriched TLR signaling and leukocyte transendothelial migration pathways, thereby forming an immune cascade of "lipid anti - inflammation - pathogen elimination - mucosal repair". Immunoprotection trials verified that priming with 1 x 104 sporulated oocysts of the precocious line significantly alleviated cecal lesions and reduced oocyst output upon secondary challenge, conferring stable mucosal immune protection. The expression trends of seven hub genes (PPARG, PLIN1, CYP1A1, THBS1, FMO4, CYP2C18, CYP14) detected via qRT - PCR were consistent with RNA - seq data. This study identified a dual regulatory paradigm consisting of NF - {kappa}B - mediated tissue injury and PPAR - {gamma} - dependent anti - inflammatory responses, refined the mucosal immune theoretical framework for commercially available precocious attenuated strains, and provided candidate molecular targets for targeted anti - coccidial intervention in chickens.

microbiology↗

bioRxiv2026

Telomere-to-telomere assembly and haplotype analysis of tetraploid Dendrobium officinale illuminate Orchidaceae polyploid evolution and mycorrhizal symbiosis genes

Dendrobium officinale is a typical epiphytic orchid. We report the telomere-to-telomere (T2T) genome assembly for D. officinale, representing the first T2T reference genome within the Orchidaceae family. The assembly is anchored to 19 chromosomes and contains 38 complete telomeres and 15 characterized centromeres. We further generated haplotype-resolved assemblies of the autotetraploid genome, identifying 12,761 sets of tetra-allelic genes. Based on synonymous substitution analysis, we inferred that the autotetraploidization event occurred approximately 0.86 million years ago. A systematic analysis of the SWEET gene family across the genus Dendrobium revealed that the gene family size is shaped primarily by epiphytic types and environmental factors. In D. officinale from Langshan, eight SWEET genes were specifically expressed in roots, suggesting they may play specialized roles in the root mycorrhizal system, potentially contributing to the D. officinales ability to recruit and maintain fungal partners. Together, these resources provide valuable foundations for studies of orchid evolution, functional genomics, and molecular breeding.

bioinformatics↗

bioRxiv2026

New insights into the evolution of spider silk proteins illuminated by long-read transcriptomes

Spider silk has long fascinated scientists because of its exceptional mechanical properties, yet the evolutionary origins and diversification of spider silk proteins (spidroins) remain incompletely understood. By analyzing long-read spidroin transcripts from spiders representing key evolutionary lineages, we identify two ancestral proteins present in basal spiders: an alanine-serine-rich (AS-type) protein and a glycine-serine-rich (GS-type) protein. These ancestral proteins likely served as primary evolutionary templates for the diversification of modern spider silks. We show that the AS-type ancestral spidroin remained relatively conserved and ultimately gave rise to the specialized tubuliform spidroin (TuSp) used in eggcase silk. In contrast, the GS-type protein underwent extensive functional radiation, evolving into differentiated minor ampullate spidroins (MiSp) through the acquisition of distinct terminal domains and {beta}-sheet-associated structural innovations. Our results further suggest that major ampullate spidroins (MaSp) may have originated from MiSp, with the GS motif representing an evolutionarily favorable genetic substrate for the emergence of high-performance silk proteins. Finally, we propose a revised evolutionary trajectory for flagelliform spidroins (Flag), suggesting that they were co-opted as components of ampullate silk during functional degeneration in modern non-web-weaving RTA clade spiders. Together, these findings provide a high-resolution framework for understanding the genetic innovations that drove the diversification of spider silk.

evolutionary biology↗

bioRxiv2026

Vascularized tumor organoids enable immunotherapy testing in tumor-remodeled stroma

Accurately predicting whether a new molecule will be safe and effective in humans remains a fundamental challenge in biomedical research, requiring models that can reliably inform clinical outcomes. In oncology, drug attrition rates remain disproportionately high compared to other therapeutic areas, largely due to the poor translatability of conventional preclinical models that fail to capture the complexity of human immune-tumor-stroma interactions (1, 2). Here, we describe human vascularized organoids (VascO), formed through self-assembly of an immune cell perfused capillary network and stromal compartment, interfacing with patient-derived colorectal cancer organoids that enable the combined safety and efficacy assessment of tumor-targeted immunotherapies. VascO generates functional and integrated vascular networks within tumor organoids that sustain organoid growth and recapitulate the morphology and functionality of tumor vasculature. Single-cell transcriptomics reveals that the tumor organoids-educated VascO niche reprograms otherwise healthy fibroblasts into canonical cancer-associated fibroblast states, adopting my-ofibroblastic or inflammatory signatures, and faithfully mirroring donor-specific tumor cues. In parallel, VascO tumor vessels display an expanded tip-cell program, aberrant morphology, and VEGF/ANG2-driven permeability, recapitulating defining hallmarks of tumor vasculature. Immune perfusion with a tumor-targeted T cell bispecific antibody induces dynamic immune trafficking, infiltration and engagement of effector cells with the tumor tissue, leading to its effective killing. A protease-activated variant restricts T cell activation to the tumor microenvironment, retaining potent tumoricidal activity while sparing donor-matched healthy colon organoids, and thereby improving the therapeutic index. VascO thus models a patient-specific, tumor-educated microenvironment that is amenable to assessing the combined safety and efficacy of new drug candidates and provides a scalable platform to improve the preclinical assessment of innovative cancer immunotherapies.

bioengineering↗

bioRxiv2026

Identification of Novel Extracellular Vesicles Scaffold Proteins for Versatile Cargo Engineering

Extracellular vesicles (EVs) are promising drug delivery platforms that have been engineered to carry various drug modalities. Key strategies for generating those therapeutic EVs involve the direct fusion of protein of interest (POI) to EVs scaffold proteins with inherently high EVs-sorting ability. In this work, we identified raftlin (RFTN1) and poliovirus receptor (PVR) as novel EVs scaffold proteins for loading EVs lumen and surface cargos respectively. Truncation studies revealed that the N-terminus 15 residues from RFTN1 (RFTN1-N15) were sufficient for EVs engineering, as demonstrated by distinct cargos including gene editing tools, cytosolic enzymes as well as type II transmembrane proteins. On the other hand, PVR efficiently displayed secreted proteins including antibodies and serum albumins on EVs surface. Critically, RFTN1 and PVR-engineered EVs demonstrated consistent and efficient cargo delivery in vivo. In summary, the discovery of RFTN1 and PVR can potentially benefit EVs engineering for both fundamental research and clinical translation in the future.

bioengineering↗

bioRxiv2025

α-Synuclein purification significantly impacts seed amplification assay performance and consistency

-Synuclein seed amplification assays are a promising diagnostic tool for synucleinopathies such as Parkinsons disease and multiple system atrophy. Standardized conditions are required to ensure a high degree of inter- and intra-laboratory reproducibility when performing these assays. A significant issue that hinders the utility of seed amplification assays is the de novo aggregation propensity of the -synuclein substrate as well as inter-batch heterogeneity. While much work has focused on determining appropriate seed amplification assay buffer compositions as well as the type and amount of seed used, a robust comparison of -synuclein substrate purification methods has not been reported. We therefore compared the utility of recombinant -synuclein purified using four different methods as seed amplification assay substrates across two laboratories. Osmotic shock-purified -synuclein monomer substrate showed the lowest propensity for de novo aggregation, which translated into being the best substrate for seed amplification assay reactions seeded with -synuclein preformed fibrils or patient brain homogenates. Furthermore, osmotic shock -synuclein monomer showed the best inter-batch reproducibility compared to all other substrates tested. As -synuclein seed amplification assays continue to evolve and move towards adoption in the clinical realm, this work showcases the vital importance of standardizing the production and characterization of recombinant -synuclein substrate. We encourage the widespread adoption of osmotic shock -synuclein monomer as the universal substrate for seed amplification assays to maximize intra- and inter-laboratory reproducibility.

biochemistry↗

bioRxiv2025

Midbrain organoids with an SNCA gene triplication display dopamine-dependent alterations in network activity

Human midbrain organoids (hMOs) show promise as a patient-derived model for the study of Parkinsons disease (PD). Yet, much remains unknown about how accurately hMOs recapitulate key features of PD in the human brain. In both PD patients and animal models, disease progression leads to characteristic changes in neural activity throughout the basal ganglia. Here we demonstrate that patient-derived induced pluripotent stem cell (iPSC) hMOs harboring a triplication in the SNCA gene, encoding -synuclein, a key protein in PD pathogenesis, can recapitulate PD-associated changes in neural activity. Namely, we observe hyperactive network activity in SNCA triplication hMOs, but not in isogenic, CRISPR-corrected iPSC hMOs. These changes are characterized by an increase in the number of bursts and network-wide bursts. Moreover, SNCA triplication hMOs exhibit an increase in network synchrony and burst/network burst strength similar to observations in animal and human PD brains. Subsequently, we show that the observed changes in neuronal activity are attributed to dopamine D2 receptor hypoactivity due to dopamine depletion, which could be reversed by the D2 receptor agonist quinpirole. Thus, hMOs faithfully model network wide electrophysiological changes associated with PD progression and serve as a promising tool for PD research and personalized medicine.

neuroscience↗

bioRxiv2025

easyEWAS: a flexible and user-friendly R package for Epigenome-Wide Association Study

MotivationRapid advancements in high-throughput sequencing technologies especially the Illumina DNA methylation Beadchip greatly fueled the surge in epigenome-wide association study (EWAS), providing crucial insights into intrinsic DNA methylation modifications associated with environmental exposure, diseases, and health traits. However, current tools are complex and less user-friendly to accommodate appropriate EWAS designs and make downstream analyses and result interpretations complicated, especially for clinicians and public health professionals with limited bioinformatic skills. ResultsWe integrated the current state-of-the-art EWAS analysis methods and tools to develop a flexible and user-friendly R package easyEWAS for conducting DNA methylation-based research using Illumina DNA methylation Beadchips. With easyEWAS, we provide a battery of statistical methods to support differential methylation position analysis across various scenarios, as well as differential methylation region analysis based on the DMRcate method. To facilitate result interpretation, we provide comprehensive functional annotation and result visualization functionalities. Additionally, a bootstrap-based internal validation was incorporated into easyEWAS to ensure the robustness of EWAS results. Evaluation in asthma patients as the example demonstrated that easyEWAS could simplify and streamline the conduction of EWAS and corresponding downstream analyses, thus effectively advancing DNA methylation research in public health and clinical settings. Availability and implementationeasyEWAS is implemented as an R package and is available at https://github.com/ytwangZero/easyEWAS. Contactxu.gao@pku.edu.cn, ytwang@pku.edu.cn

bioinformatics↗

bioRxiv2024

Therapeutic targeting of KRAS mutation-driven tumorigenesis by extracellular vesicles loaded with small interfering RNA

RAS is a well-known oncogene contributing to significant proportion of cancer incidences, yet it remains as an undruggable target to majority of therapeutic modalities. Here, we explored the potential of extracellular vesicles (EVs) for therapeutic targeting of KRAS mutation-driven tumorigenesis. EVs loaded with small interfering RNA (siRNA) against KRAS successfully inhibited tumor xenograft growth when injected intratumorally in mice models. Intriguingly, when injected intravenously, EVs were still able to accumulate in tumors and deliver KRAS targeting siRNA payload in sufficient amount to show tumor growth inhibition. Therefore, EV-siRNA platform show great promises for therapeutic targeting of KRAS mutations and other undruggable targets.

cancer biology↗

bioRxiv2023

Generation of CRISPR-edited birch Plants without DNA integration using Agrobacterium-mediated Transformation Technology

CRISPR/Cas9 system has emerged as a powerful tool in genome editing; however, generation of CRISPR-edited DNA-free plants is still challenging. In this study, Betula platyphylla (birch) was used to build a method to generate CRISPR-edited plant without foreign DNA integration using Agrobacterium-mediated transformation (CPDAT method). This technique utilizes transient genetic transformation to introduce T-DNA coding gRNA and Cas9 into birch cells, and T-DNA will express to synthesize gRNA and Cas9 protein, which will form a complex to cleave the target DNA site. The genome may be mutated due to DNA repair, and these mutations will be preserved and accumulated not dependent on whether T-DNA is integrated into the genome or not. After transient transformation, birch plants were cut into explants to induce adventitious buds without antibiotic selection pressure. Each adventitious bud can be considered as an independent potentially CRISPR-edited line for mutation detection. CRISPR-edited birch plants without foreign DNA integration are further selected by screening CRISPR-edited lines without T-DNA integration. Among 65 randomly chosen independent lines, the mutation rate was 80.00% including 40.00% of lines with both alleles mutated. In addition, 5 lines out of 65 studied lines (7.69%) were CRISPR-edited birch plants without DNA integration. In conclusion, this innovative method presents a novel strategy for generating CRISPR-edited birch plants, thereby significantly enhancing the efficiency of generating common CRISPR-edited plants. These findings offer considerable potential to develop plant genome editing techniques further.

genetics↗

bioRxiv2023

Harnessing extracellular vesicles for efficient siRNA delivery in vitro and in vivo

To fulfill the potential of small interference RNA (siRNA) therapeutics, diverse and efficient delivery platforms for siRNA are urgently needed. Extracellular vesicles (EVs) are endogenous, cell secreted nano-vehicles which have been explored for functional siRNA delivery, yet impurities in EVs preparation and lack of efficient siRNA loading method have been limiting its further development into clinical applications. In this work, we have achieved high quality EVs production and an siRNA loading system via EVs. The prepared EV-siRNA system was able to deliver siRNA cargo to model cell lines to silence the expression of targeted genes with high potency. Furthermore, EV-siRNA administration in a tumor xenograft model significantly inhibited tumor growth. Therefore, this study establishes an innovative and efficient EV-siRNA platform for siRNA delivery in vitro and in vivo.

cancer biology↗

bioRxiv2022

Topological supramolecular network enabled highly conductive and stretchable organic bioelectronics

Intrinsically stretchable bioelectronic devices based on soft and conducting organic materials have been regarded as the ideal interface for seamless and biocompatible integration with the human body. However, the grand challenge remains for the conducting polymer to possess both high mechanical ductility and good electrical conduction at cellular level feature sizes. This longstanding material limitation in organic bioelectronics has impeded the full exploitation of its unique benefits. Here, we introduce a new molecular engineering strategy based on rationally designed topological supramolecular networks, which allows effective decoupling of competing effects from multiple molecular building blocks to meet complex requirements. We achieve two orders of magnitude improvement in the conductivity under 100% strain in physiological environment, along with the capability for direct photopatterning down to 2 m. These unprecedented capabilities allow us to realize previously inaccessible bioelectronic applications including high-resolution monitoring of soft and malleable creatures, e.g., octopus, and localized neuromodulation down to single nucleus precision for controlling organ-specific activities through delicate tissues, e.g., brainstem.

bioengineering↗

bioRxiv2022

Wireless closed-loop smart bandage for chronic wound management and accelerated tissue regeneration

Chronic non-healing wounds represent a major source of morbidity for patients and a significant economic burden. Current wound care treatments are generally passive and are unable to adapt to changes in the wound environment in real time. By integrating multimodal sensors and adding stimulators in a bandage, real-time physiological monitoring is possible and provides an opportunity for active intervention into the complex wound environment. Here, we develop a battery-free flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with tissue-interfacing tough conducting hydrogel electrodes for robust signal transduction, on-demand adhesion, and detachment. Using multiple pre-clinical models, we demonstrate the capability of our wound care system to continuously monitor skin impedance and temperature, to trigger directional electrical stimulation. The accelerated wound closure was confirmed to be due to the activation of pro-regenerative genes linked to accelerated wound closure, increased neovascularization, and enhanced dermal recovery.

bioengineering↗

bioRxiv2020

Lower Soil Carbon Loss Due to Persistent Microbial Adaptation to Climate Warming

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. Despite intensive studies for two decades, the magnitude, direction, and duration of such feedbacks are uncertain, and their underlying microbial mechanisms are still poorly understood. Here we examined the responses of soil respiration and microbial community structure to long-term experimental warming in a temperate grassland ecosystem. Our results indicated that the temperature sensitivity of soil microbial respiration (i.e., Q10) persistently decreased by 12.0{+/-}3.7% across 7 years of warming. Integrated metagenomic and functional analyses showed that microbial community adaptation played critical roles in regulating respiratory acclimation. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improved the modeling performance of soil microbial respiration by 5-19%, compared to the traditional non-microbial model. Model parametric uncertainty was also reduced by 55-71% when gene abundances were used. In addition, our modeling analyses suggested that decreased temperature sensitivity could lead to considerably less heterotrophic respiration (11.6{+/-}7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.

ecology↗

bioRxiv2018

Penaeidins are a novel family of antiviral effectors against WSSV in shrimp

Penaeidins are members of a family of key effectors with broad anti-bacterial activities in penaeid shrimp. However, the function of penaeidins in antiviral immunity is rarely reported and remains largely unknown. Herein, we uncovered that penaeidins are a novel family of antiviral effectors against white spot syndrome virus (WSSV). Firstly, RNAi in vivo mediated knockdown of each penaeidin from four identified penaeidins from Litopenaeus vannamei resulted in elevated viral loads and rendered shrimp more susceptible to WSSV, whilst the phenotype of survival rate in penaeidin-silenced shrimp can be rescued via the injection of recombinant penaeidin proteins. Moreover, pull-down assays demonstrated the conserved PEN domain of penaeidin was able to interact with WSSV structural proteins. Furthermore, we observed that colloidal gold-labeled penaeidins were located on the outer surface of the WSSV virion. By infection-blocking assay, we observed that hemocytes had lower viral infection rates in the group of WSSV preincubated with penaeidins than those of control group. Phagocytic activity analysis further showed that penaeidins were able to inhibit phagocytic activity of hemocytes against WSSV Taken together, these results suggest that penaeidins specifically binds to WSSV virion by interacting with its structural proteins, thus preventing viral infection that confers host against WSSV. In addition, dual-luciferase assay and EMSA assay demonstrated that penaeidins were regulated by Dorsal and Relish, two transcription factors of the canonical Toll and IMD pathway, respectively. To our best knowledge, this is the first report on uncovering the antiviral function of penaeidins in the innate immune system of shrimp.\n\nImportancesWhite spot syndrome, caused by white spot syndrome virus (WSSV), is the most serious disease in shrimp aquaculture, which has long been a scourge of cultured shrimp industry. Herein, we provided some substantial evidences to indicate that penaeidins are a novel family of effectors with antiviral activity against WSSV in shrimp. Penaeidins such as BigPEN, PEN2 and PEN3 were able to interact with the outer surface of WSSV virion via binding to viral structural proteins, and thus preventing viral entry host cells. In addition, we demonstrated that the Toll and IMD signaling pathways can regulate the transcriptional expression of penaeidins, which may suggest an important role of the conserved innate signaling pathways in antiviral immunity. This is the first report of the antiviral mechanism of penaeidins in shrimp, which may provide some new insights into strategies to control WSSV infection in shrimp farms.

immunology↗