Biology subjects

Xu, L.

Publications and source records attributed to Xu, L..

At least 181 records · Page 10Linked to original sources

bioRxiv2024

BayeSMART: Bayesian Clustering of Multi-sample Spatially Resolved Transcriptomics Data

The field of spatially resolved transcriptomics (SRT) has greatly advanced our understanding of cellular microenvironments by integrating spatial information with molecular data collected from multiple tissue sections or individuals. However, methods for multi-sample spatial clustering are lacking, and existing methods primarily rely on molecular information alone. This paper introduces BayeSMART, a Bayesian statistical method designed to identify spatial domains across multiple samples. BayeSMART leverages artificial intelligence (AI)-reconstructed single-cell level information from the paired histology images of multi-sample SRT datasets while simultaneously considering the spatial context of gene expression. The AI integration enables BayeSMART to effectively interpret the spatial domains. We conducted case studies using four datasets from various tissue types and SRT platforms and compared BayeSMART with alternative multi-sample spatial clustering approaches and a number of state-of-the-art methods for single-sample SRT analysis, demonstrating that it surpasses existing methods in terms of clustering accuracy, interpretability, and computational efficiency. BayeSMART offers new insights into the spatial organization of cells in multi-sample SRT data.

bioinformatics↗

bioRxiv2024

Effects of lambda-cyhalothrin on gut microbiota and related bile acid metabolism in mice

BackgroundSince the gut microbiota plays a crucial role in host metabolism and homeostasis, its alterations induced by xenobiotics, such as pesticides, could pose a risk to host health. Our previous in vitro fermentation study showed that pyrethroid pesticides could affect the mouse bacterial community and related bile acid profiles. Hence in the present study, the effects of the selected pyrethroid lambda-cyhalothrin on the intestinal microbial community and its related bile acid metabolism were evaluated in male and female mice. ResultsThe total amount of bile acids in plasma and fecal samples from lambda-cyhalothrin treated mice markedly increased compared to controls, which could be mainly ascribed to the significantly raised proportions of taurine conjugated bile acids in plasma, and the increase in fecal secondary bile acids. In gut microbial profiles, a significantly increased richness of Prevotellacea and a depletion of Lachnospiraceae were found at the family level upon the treatment with lambda-cyhalothrin. ConclusionTreatment of mice with lambda-cyhalothrin affected the gut microbiota with accompanying changes in bile acid homeostasis. The effects on fecal bile acid profiles were in line with those previously observed in our in vitro study and corroborate that pyrethroid pesticides could affect gut microbiota and related bile acid profiles.

microbiology↗

bioRxiv2024

Induction of Ferroptosis by an Amalgam of Extracellular Vesicles and Iron Oxide Nanoparticles Overcomes Cisplatin Resistance in Lung Cancer

Extracellular vesicles (EVs) hold potential as effective carriers for drug delivery, providing a promising approach to resolving challenges in lung cancer treatment. Traditional treatments, such as with the chemotherapy drug cisplatin, encounter resistance in standard cell death pathways like apoptosis, prompting the need to explore alternative approaches. This study investigates the potential of iron oxide nanoparticles (IONP) and EVs to induce ferroptosis--a regulated cell death mechanism--in lung cancer cells. We formulated a novel EV and IONP-based system, namely ExoFeR, and observed that ExoFeR demonstrated efficient ferroptosis induction, evidenced by downregulation of ferroptosis markers (xCT/SLC7A11 and GPX4), increased intracellular and mitochondrial ferrous iron levels, and morphological changes in mitochondria. To enhance efficacy, tumor-targeting transferrin (TF)-conjugated ExoFeR (ExoFeRTF) was developed. ExoFeRTF outperformed ExoFeR, exhibiting higher uptake and cell death in lung cancer cells. Mechanistically, nuclear factor erythroid 2-related factor 2 (Nrf2)--a key regulator of genes involved in glutathione biosynthesis, antioxidant responses, lipid metabolism, and iron metabolism--was found downregulated in the ferroptotic cells. Inhibition of Nrf2 intracellular translocation in ExoFeRTF-treated cells was also observed, emphasizing the role of Nrf2 in modulating ferroptosis-dependent cell death. Furthermore, ExoFeR and ExoFeRTF demonstrated the ability to sensitize chemo-resistant cancer cells, including cisplatin-resistant lung cancer patient-derived tumoroid organoids. In summary, ExoFeRTF presents a promising and multifaceted therapeutic approach for combating lung cancer by intrinsically inducing ferroptosis and sensitizing chemo-resistant cells.

cancer biology↗

bioRxiv2024

Bioinspired Bimetallic Ions Functionalized MOF SAzyme Nanocomposites for Synergistic Ferroptosis/Cuproptosis-Enhanced Immune Checkpoint Therapy

Immune checkpoint blockade (ICB) generates sustained responses in immunogenic cancers, but its effectiveness is limited in tumors lacking immune activity. Here, we construct a bioinspired bimetallic ions functionalized nanoscale metal-organic framework (NMOF) single-atom nanozyme (SAzyme) loaded with doxorubicin (Dox) (NMOF-Fe/Cu-Dox nanocomposite) to effectively trigger anti-tumor immune responses while addressing the immunosuppressive tumor microenvironment (TME). The NMOF-Fe/Cu-Dox nanocomposite has been demonstrated to efficiently reverse the TME by generating reactive oxygen species and oxidizing glutathione. Camouflaging NMOF-Fe/Cu-Dox nanocomposites with bioinspired cancer cell membrane (NMOF-Fe/Cu-Dox@M) enables its navigation to the tumor region through homologous targeting. The highly efficient uptaken by cancer cells selectively induced synergistic ferroptosis and cuproptosis in these cells. Furthermore, in vitro and in vivo experiments demonstrate that the ferroptosis in cancer cells can polarize tumor-associated macrophages (TAMs) towards anti-tumoral M1 phenotype and significantly diminish pro-tumoral M2 phenotype. We find that NMOF-Fe/Cu-Dox@M could induce the ferroptosis of M2 macrophages, while no effect to M1 macrophages. In addition, a significant increase of anti-tumor infiltrating CD8+ T cells, while a remarkable decrease of CD4+ regulatory T cells were observed. These findings suggested that NMOF-Fe/Cu-Dox@M could efficiently modulate TME, enhance tumoricidal immunity and elevate the therapeutic efficiency of ICB. Moreover, the combination of NMOF-Fe/Cu-Dox@M with PD-1 effectively eradicated hepatocellular carcinoma cells in vivo, outperforming the use of either NMOF-Fe/Cu-Dox@M or PD-1 alone. In summary, our study presents a therapeutic strategy that leverages coordinated ferroptosis and cuproptosis with therapeutic efficiency of ICB, underscoring the promise of combined chemoimmunotherapy.

bioengineering↗

bioRxiv2024

Interpretable improving prediction performance of general protein language model by domain-adaptive pretraining on DNA-binding protein

DNA-protein interactions exert the fundamental structure of many pivotal biological processes, such as DNA replication, transcription, and gene regulation. However, accurate and efficient computational methods for identifying these interactions are still lacking. In this study, we propose a novel method ESM-DBP through refining the DNA-binding protein (DBP) sequence repertory and domain-adaptive pretraining based the protein language model (PLM). Our method considers the lack of exploration of general PLM for DBP domain-specific knowledge, so we screened out 170,264 DBPs from the UniProtKB database to construct the model that more suitable for learning crucial characteristics of DBP. The evaluation of ESM-DBP is systematically performed in four different DBP-related downstream prediction tasks, i.e., DNA-binding protein, DNA-binding residue, transcription factor, and DNA-binding Cys2His2 zinc-finger predictions. Experimental results show that ESM-DBP provides a better feature representation of DBP compared to the original PLM, resulting in improved prediction performance and outperforming other state-of-the-art prediction methods. In addition, ESM-DBP incorporates the integrated gradient algorithm for interpretable analysis, which usually ignored in the previous methods. It reveals that ESM-DBP possesses high sensitivity to the key decisive DNA-binding domains. Moreover, we find that ESM-DBP can still perform well even for those DBPs with only a few similar homologous sequences, and this generalization performs better than the original PLM. The data and standalone program of ESM-DBP are freely accessible at https://github.com/pengsl-lab/ESM-DBP.

bioinformatics↗

bioRxiv2024

The assembly of Y chromosome reveals amplification of genes regulating male fertility in Bactrocera dorsalis

BACKGROUNDThe oriental fruit fly Bactrocera dorsalis is an invasive pest causing considerable ecological and economic damage worldwide. The Y chromosome is an important target for the sterile insect technique (SIT) but its sequence and structure has been poorly explored. RESULTSWe assembled the genome of B. dorsalis at the chromosome level with a total size of 562.6 Mb. The assembly includes a [~]7.6 Mb Y chromosome sequence, being the first reported Y chromosome in Tephritidae. The assembled Y chromosome is highly repetitive, and contains 61 genes, including 9 multi-copy genes. We surprisingly found that the M factor (MoY) in Tephritidae has multiple copies, verified by our droplet digital PCR (ddPCR) analysis. Besides, we identified 32 copies of gyf-like on the Y chromosome (gyfY) that were highly expressed in testis. RNAi targeting the gyfY resulted in depletion of live sperms, suggesting that the amplification of gyfY is essential for male fertility, which facilitated the understanding of high fecundity of this invasive insect. CONCLUSIONWe reported firstly the Y chromosome of Bactrocera dorsalis. Our results will also provide target genes for CRISPR/Cas9 based SIT, leading to the development of novel control strategies against tephritid flies.

zoology↗

bioRxiv2024

Empowering Integrative and Collaborative Exploration of Single-Cell and Spatial Multimodal Data with SGS

Recent advancements in single-cell and spatial omics technologies have revolutionized our ability to capture multiple modalities data at a genome-wide scale within individual cells. However, visualizing these large-scale, high-dimensional, and complex datasets poses significant challenges. Here, we present SGS, a user-friendly, collaborative and versatile browser for visualizing single-cell and spatial multiomics data. SGS incorporates a novel genome browser framework, flexible visualization modules and a multi-panel adaptive communication mechanism to enable the synchronous visualization of diverse datasets. Notably, SGS empowers users with advanced capabilities for comparative visualization, through features like scCompare, scMultiView, and dual-chromosome module. Additionally, by adopting the "workstation concept", SGS enables data fast visualization and collaborative exploration. We showcase the potential of SGS in the comparative visualization and coordinated exploration of mutlimodal data with two examples. SGS is publicly available at https://sgs.bioinfotoolkits.net/home.

bioinformatics↗

bioRxiv2024

Spatiotemporal transcriptomic profiling and modeling of mouse brain at single-cell resolution reveals cell proximity effects of aging and rejuvenation

Old age is associated with a decline in cognitive function and an increase in neurodegenerative disease risk1. Brain aging is complex and accompanied by many cellular changes2-20. However, the influence that aged cells have on neighboring cells and how this contributes to tissue decline is unknown. More generally, the tools to systematically address this question in aging tissues have not yet been developed. Here, we generate spatiotemporal data at single-cell resolution for the mouse brain across lifespan, and we develop the first machine learning models based on spatial transcriptomics ( spatial aging clocks) to reveal cell proximity effects during brain aging and rejuvenation. We collect a single-cell spatial transcriptomics brain atlas of 4.2 million cells from 20 distinct ages and across two rejuvenating interventions--exercise and partial reprogramming. We identify spatial and cell type-specific transcriptomic fingerprints of aging, rejuvenation, and disease, including for rare cell types. Using spatial aging clocks and deep learning models, we find that T cells, which infiltrate the brain with age, have a striking pro-aging proximity effect on neighboring cells. Surprisingly, neural stem cells have a strong pro-rejuvenating effect on neighboring cells. By developing computational tools to identify mediators of these proximity effects, we find that pro-aging T cells trigger a local inflammatory response likely via interferon-{gamma} whereas pro-rejuvenating neural stem cells impact the metabolism of neighboring cells possibly via growth factors (e.g. vascular endothelial growth factor) and extracellular vesicles, and we experimentally validate some of these predictions. These results suggest that rare cells can have a drastic influence on their neighbors and could be targeted to counter tissue aging. We anticipate that these spatial aging clocks will not only allow scalable assessment of the efficacy of interventions for aging and disease but also represent a new tool for studying cell-cell interactions in many spatial contexts.

neuroscience↗

bioRxiv2024

A long non-coding RNA LINC00094 regulates the transcriptional expression of lipid metabolism-related genes as a new member of core regulatory circuitry in esophageal squamous cell carcinoma

LINC00094 as a new supper-enhancer (SE)-related long non-coding RNA is associated with poor overall survival of patients with esophageal squamous cell carcinoma (ESCC). However, the transcriptional regulatory mechanism of LINC00094 and the molecular mechanisms by which LINC00094 affects the phenotype of ESCC remains unclear. Here, we found that LINC00094 promoted the proliferation of ESCC cells both in vitro and in vivo. LINC00094 knockdown significantly reduced the expression profiles of transcription activators including transcription factor 3 (TCF3) and Kruppel like factor 5 (KLF5) and lipid metabolism-related genes. Mechanically, TCF3 and KLF5 formed a core regulatory circuitry (CRC) that bound to the SEs of LINC00094 and to their own SEs to regulate the transcriptional expression in a positive feedback loop. LINC00094 recruited TCF3 and KLF5 to form a ternary complex, which forms a new CRC with TCF3 and KLF5 that regulated its own transcription as well as lipid metabolism-related genes. Knockdown of any or all three genes inhibited the expression of genes related to lipid synthesis and consistently reduced total lipid droplet levels. Treatment with SEs inhibitors (THZ1 and JQ1) effectively inhibited the formation of this CRC and the production of lipid droplets in ESCC cells. The high-risk group of CRC-associated signatures were closely associated with poor prognosis in patients with ESCC. Our findings suggest that LINC00094 is involved in the CRC by forming a complex with TCF3 and KLF5, and this regulation model can affect the phenotype of ESCC cells by controlling the expression of lipid metabolism-related genes. HighlightsO_LIWe identified a novel functional lncRNA-LINC00094 for esophageal squamous cell carcinoma. C_LIO_LILINC00094 forms a complex with the core transcription factors TCF3 and KLF5, thereby forming a core regulatory circuitry to participate in transcriptional regulation in ESCC. C_LIO_LIA core regulatory circuitry mediated by LINC00094 regulates lipid metabolism in ESCC. C_LI

cancer biology↗

bioRxiv2024

Deep mutational scanning reveals sequence to function constraints for SWEET family transporters

Protein science is entering a transformative phase enabled by deep mutational scans that provide an unbiased view of the residue level interactions that mediate function. However, it has yet to be extensively used to characterize the mutational and evolutionary landscapes of plant proteins. Here, we apply the method to explore sequence-function relationships within the sugar transporter AtSWEET13. DMS results describe how mutational interrogation throughout different regions of the protein affects AtSWEET13 abundance and transport function. Our results identify novel transport-enhancing mutations that are validated using the FRET sensor assays. Extending DMS results to phylogenetic analyses reveal the role of transmembrane helix 4 (TM4) which makes the SWEET family transporters distinct from prokaryotic SemiSWEETs. We show that transmembrane helix 4 is intolerant to motif swapping with other clade-specific SWEET TM4 compositions, despite accommodating single point-mutations towards aromatic and charged polar amino acids. We further show that the transfer learning approaches based on physics and ML based In silico variant prediction tools have limited utility for engineering plant proteins as they were unable to reproduce our experimental results. We conclude that DMS can produce datasets which, when combined with the right predictive computational frameworks, can direct plant engineering efforts through derivative phenotype selection and evolutionary insights.

plant biology↗

bioRxiv2024

Stable platelet production via the bypass pathway explains the long-term reconstitution capacity of hematopoietic stem cells

Precise understanding how hematopoietic stem cells (HSCs) differentiate in vivo is difficult because we can not trace the in vivo differentiation of HSCs. The single-cell transplantation assay and our own paired daughter cell assay of phenotypic HSCs has revealed the presence of HSCs with reconstitution capacity whose differentiation potential is restricted to the myeloid lineage (MySCs) and the presence of novel direct differentiation pathway form HSCs to MySCs (named myeloid bypass pathway). However, how HSCs differentiate in vivo during hematopoiesis has remained unclear since the paired daughter cell assay was performed partially ex vivo. Aiming to characterize HSCs, including the myeloid bypass pathway, we examined the kinetics of HSC differentiation using a mathematical model. We analyzed data from single-cell transplantation assays in which five blood cell lineages were followed successively after transplantation. An age-related skewing to the myeloid lineage was quantitatively indicated as the production of B cells reduced with age. Dependence on platelet bypass increased with aging and consistently high dependence was associated with long-term reconstitution capacity of the HSCs. Focusing on the ratio of chimerism among cell lineages, the characteristics of dependence on platelet bypass can be accurately determined by the ratio of erythrocyte to platelet chimerism at 8 weeks after transplantation. This new identification criterion is an indicator of long-term reconstitution of HSCs that does not rely on observation of long-term transplantation experiments. These findings reveal the novel characteristics of HSCs related to aging and stemness and highlight the importance of the bypass pathway in HSC differentiation. Significance statementIn vivo differentiation of hematopoietic stem cells (HSCs) is important for understanding blood cell production. Here we investigated the differentiation kinetics of HSCs in single-cell transplantation assays by using a mathematical model. Our findings demonstrate the importance of the bypass pathway in platelet production for the long-term reconstitution capacity of HSCs. These results also suggest the utility of studying time changes in HSC differentiation. The new HSC characteristics and its detection criteria identified in this study are expected to be useful in understanding HSC diversity and aging.

cell biology↗

bioRxiv2024

The effects of L-carnitine and fructose in improved Ham's F10 on sperm culture in idiopathic severe asthenospermia within 24h

Trial designTo study the effects of L-carnitine and fructose on semen parameters of severe asthenospermia patients by sperm culturing in vitro within 24h. We optimized the energy composition and antioxidant substances of sperm culture medium in vitro (based on Hams F10 culture medium) by orthogonal test for preparing high quality culture medium. Sperms of 60 patients with idiopathic severe asthenospermia were collected, and cultured in vitro within 24h, by Hams F10 culture medium added to different concentrations of L-carnitine and fructose and culture temperature, whose effects on sperm motility were observed to determine which is the most appropriate concentration and temperature. MethodsFor determining the appropriate concentration of L-carnitine and fructose and the suitable culture temperature in Hams F10 culture medium, the orthogonal experiments were carried out to optimize above three factors, which had great influence on sperm viability, survival rate, deformity rate and DNA fragmentation index (DFI). ResultsThe final concentration of L-carnitine and fructose was determined in terms of initial tests to assess the effects of different concentrations (4, 8, 12, and 16 mg/ml L-carnitine and 0.125, 0.250, 0.375, and 0.50 mg/ml fructose) on sperm viability and motility in culture. During the operation of processing and culturing sperms in vitro within 24h, orthogonal test showed that sperm viability was better at the final concentration of 8 mg/ml L-carnitine and 0.375 mg/mL fructose in improved Hams F10 culture medium at 36.5 . ConclusionIdiopathic severe asthenospermia sperm can be effectively improved by the modified Hams F10 culture medium of the final concentration of 8 mg/ml L- carnitine and 0.375 mg/mL fructose in at 36.5 within 24h, which has shown better culture effect and is superior to Hams F10 basic medium.

biochemistry↗

bioRxiv2024

Actinomycin D and bortezomib disrupt protein homeostasis in Wilms tumor

Wilms tumor is the most common kidney cancer in children, and diffuse anaplastic Wilms tumor is the most chemoresistant histological subtype. Here, we explore how Wilms tumor cells evade the common chemotherapeutic drug actinomycin D, which inhibits ribosomal RNA biogenesis. Using ribosome profiling, protein arrays, and a genome-wide knockout screen, we describe how actinomycin D disrupts protein homeostasis and blocks cell cycle progression. We found that, when ribosomal capacity is limited by actinomycin D treatment, anaplastic Wilms tumor cells preferentially translate proteasome components and upregulate proteasome activity. Based on these findings, we tested whether the proteasome inhibitor bortezomib sensitizes cells to actinomycin D treatment. Indeed, we found that the combination induces apoptosis both in vitro and in vivo and prolongs survival in xenograft models. Lastly, we show that increased levels of proteasome components are associated with anaplastic histology and worse prognosis in Wilms tumor patients. In sum, maintaining protein homeostasis is critical for Wilms tumor proliferation, and it can be therapeutically disrupted by blocking protein synthesis or turnover.

cancer biology↗

bioRxiv2024

The long-chain fatty acid-CoA ligase FadD1 monitors Pseudomonas aeruginosa quorum sensing as a receptor of cis-2-decenoic acid

Diffusible signal factor (DSF)-family quorum sensing (QS) signals are widely utilized by many bacterial pathogens to modulate various biological functions and virulence. Previous studies showed that cis-2-decenoic acid (cis-DA) is involved in modulation of biofilm dispersion in Pseudomonas aeruginosa, but its signaling mechanism remains vague. Here, we report that cis-DA regulates the physiology and virulence of P. aeruginosa through the long-chain fatty acid-CoA ligase FadD1. Cis-DA specifically binds to FadD1 with high affinity and enhances the binding of FadD1 to the promoter DNA region of lasR. Further analysis showed that the FadD1 is a response regulator of cis-DA with a DNA-binding leucine zipper motif to control the transcription of various target genes. Moreover, FadD1 exhibited catalytic activity on cis-2-dodecenoic acid (BDSF) of Burkholderia cenocepacia and enhanced the competitiveness of P. aeruginosa. Together, our work presents a new DSF-type QS signaling system, which is highlighted by its receptor and response regulator evolved from a canonical enzyme of fatty acid metabolism. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/598097v2_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@66b8aaorg.highwire.dtl.DTLVardef@1e5b9b9org.highwire.dtl.DTLVardef@1043525org.highwire.dtl.DTLVardef@13d3ed1_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsThe long-chain fatty acid-CoA ligase FadD1 acts as a global transcriptional regulator in P. aeruginosa. FadD1 is a receptor of QS signal cis-DA and functions at the top of the QS hierarchy in P. aeruginosa. The homolog of FadD1 in P. fluorescens could bind to the target gene promoter by responding to cis-DA. In briefPseudomonas aeruginosa is a human pathogen with antibiotic resistance and a wide range of dynamic defenses makes it an extremely challenging organism to treat in modern-day medicine. It employs cis-2-decenoic acid (cis-DA) quorum sensing to regulate the physiology and pathogenesis. Song et al. demonstrate that the long-chain fatty acid-CoA ligase FadD1 controls the important biological functions and virulence in P. aeruginosa as a novel response regulator of cis-DA signal.

microbiology↗

bioRxiv2024

CLCC1 Governs Bilayer Equilibration at the Endoplasmic Reticulum to Maintain Cellular and Systemic Lipid Homeostasis

The intricate orchestration of lipid production, storage, and mobilization is vital for cellular and systemic homeostasis1,2. Dysfunctional plasma lipid control represents the major risk factor for cardio-metabolic diseases, the leading cause of human mortality3,4. Within the cellular landscape, the endoplasmic reticulum (ER) is the central hub of lipid synthesis and secretion, particularly in metabolically active hepatocytes in the liver or enterocytes in the gut5,6. Initially assembled in the ER lumen, lipid-ferrying lipoproteins necessitate the cross-membrane transfer of both neutral and phospho-lipids onto the lumenal apolipoprotein B (APOB), in a poorly-defined process7-10. Here we show that trans-bilayer equilibration of phospholipids, regulated by the ER protein CLCC1, determines lipid partition across the ER membrane and consequently systemic lipid homeostasis. CLCC1 partners with the phospholipid scramblase TMEM41B11,12 to recognize imbalanced bilayers and promote lipid scrambling, thereby licensing lipoprotein biogenesis and the subsequent bulk lipid transport. Strikingly, loss of CLCC1 or TMEM41B leads to the emergence of giant lumenal lipid droplets enclosed by extensively imbalanced ER bilayers, and consequently drastically accelerated pathogenesis of metabolic-dysfunction-associated liver steatohepatitis (MASH). The above results establish phospholipid scrambling at the ER as the lynchpin to maintain a dynamic equilibrium. Considering the requirement of trans-bilayer phospholipid equilibration in numerous biological processes, ranging from catabolic autophagy to viral infection13-16, our study may enable further elucidation of a previously under-appreciated homeostatic control mechanism intrinsic to the ER function in lipid biogenesis and distribution.

cell biology↗

bioRxiv2024

A Regularized Bayesian Dirichlet-multinomial Regression Model for Integrating Single-cell-level Omics and Patient-level Clinical Study Data

SummaryThe abundance of various cell types can vary significantly among patients with varying phenotypes and even those with the same phenotype. Recent scientific advancements provide mounting evidence that other clinical variables, such as age, gender, and lifestyle habits, can also influence the abundance of certain cell types. However, current methods for integrating single-cell-level omics data with clinical variables are inadequate. In this study, we propose a regularized Bayesian Dirichlet-multinomial regression framework to investigate the relationship between single-cell RNA sequencing data and patient-level clinical data. Additionally, the model employs a novel hierarchical tree structure to identify such relationships at different cell-type levels. Our model successfully uncovers significant associations between specific cell types and clinical variables across three distinct diseases: pulmonary fibrosis, COVID-19, and non-small cell lung cancer. This integrative analysis provides biological insights and could potentially inform clinical interventions for various diseases.

bioinformatics↗

bioRxiv2024

TRIM32 inhibits Venezuelan Equine Encephalitis Virus Infection by targeting a late step in viral entry

Alphaviruses are mosquito borne RNA viruses that are a reemerging public health threat. Alphaviruses have a broad host range, and can cause diverse disease outcomes like arthritis, and encephalitis. The host ubiquitin proteasome system (UPS) plays critical roles in regulating cellular processes to control the infections with various viruses, including alphaviruses. Previous studies suggest alphaviruses hijack UPS for virus infection, but the molecular mechanisms remain poorly characterized. In addition, whether certain E3 ubiquitin ligases or deubiquitinases act as alphavirus restriction factors remains poorly understood. Here, we employed a cDNA expression screen to identify E3 ubiquitin ligase TRIM32 as a novel intrinsic restriction factor against alphavirus infection, including VEEV-TC83, SINV, and ONNV. Ectopic expression of TRIM32 reduces alphavirus infection, whereas depletion of TRIM32 with CRISPR-Cas9 increases infection. We demonstrate that TRIM32 inhibits alphaviruses through a mechanism that is independent of the TRIM32-STING-IFN axis. Combining reverse genetics and biochemical assays, we found that TRIM32 interferes with genome translation after membrane fusion, prior to replication of the incoming viral genome. Furthermore, our data indicate that the monoubiquitination of TRIM32 is important for its antiviral activity. Notably, we also show two TRIM32 pathogenic mutants R394H and D487N, related to Limb-girdle muscular dystrophy (LGMD), have a loss of antiviral activity against VEEV-TC83. Collectively, these results reveal that TRIM32 acts as a novel intrinsic restriction factor suppressing alphavirus infection and provides insights into the interaction between alphaviruses and the host UPS. Author summaryDue to climate change, wildlife habitat loss, and human activities, alphavirus infections are a growing threat to public health. The host UPS has critical role in virus-host interaction, but how the UPS impact alphavirus infection is not completely understood. In this study, we found that the E3 ubiquitin ligase TRIM32 inhibits diverse alphaviruses in multiple cell types. Mechanistically, TRIM32 impairs primary translation of incoming viral genome in a manner that depends on. monoubiquitination of TRIM32. Additionally, disease-associated alleles of TRIM32 have a loss-of-function with respect to viral inhibition. Together, these findings uncover a novel biological function of TRIM32 in regulating alphavirus infection and provide important insights into the interplay between alphaviruses and the host USP.

microbiology↗

bioRxiv2024

Functional and Clinical Implications of Extrachromosomal Circular DNA in the Human Germline

Extrachromosomal circular DNA (eccDNA) originates from linear chromosomal DNA and can be found in various human cell types including the male germline. However, the functional effects and biogenesis mechanisms of the eccDNA in the human male germline are not well understood. Here, we developed a sequencing approach to extract eccDNA sequence information and the paired transcriptome information from the same cells. By applying this approach to human samples, we found evidence of transcriptional activities of germline eccDNAs. We also showed that patients with chronic diseases such as hypertension and diabetes had a significantly higher number of eccDNAs in the sperm than their healthy counterparts. This was, at least partly, due to an increased apoptosis signaling in the germline. Analysis of single cell RNA sequencing data of spermatogenic cells from diabetic patients vs. healthy individuals suggested that a dysregulation in the expression levels of multiple poly (ADP-ribose) polymerases may contribute to the increased amount of germline eccDNAs in diseased patients. In addition, we identified a potential horizontal transfer mechanism through which healthy sperm can take up eccDNAs from their surrounding microenvironment. Together, our results suggest that eccDNA may have functional effects on the germline, and it may serve as a non-invasive clinical biomarker for human health.

genomics↗