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Biomedical subjects

Xin Liu

Publications and source records attributed to Xin Liu.

11 recordsLinked to original sources

Environmental Gradients as a Dominant Force in the Macroevolution of a Host-Associated Marine Bacterium.

Natural selection is imposed by both abiotic environmental filtering and biotic interactions, yet their relative roles in shaping the deep phylogeny of widespread, generalist host-associated bacteria remain unclear. Here, we integrate large-scale phylogenomics, environmental sequencing, functional genomics, and global metagenomic analysis to demonstrate that tidal zonation overrides host association as the dominant macroevolutionary force structuring the marine bacterial genus Ruegeria. Analysis of 533 genomes and 74 global coastal metagenomes reveals that the intertidal-subtidal boundary structures the deepest phylogenetic splits, driving the repeated evolution of distinct ecotypes through independent zonation transitions across global coastlines. These ecotypes possess divergent genomic toolkits: intertidal strains are enriched for genes coding for stress resistance and anaerobic metabolism, whereas subtidal strains specialize in high-affinity nutrient scavenging. Our findings establish that predictable physicochemical gradients act as filters that generate foundational diversity from which specialized host symbionts subsequently emerge, reframing how environmental gradients shape microbial evolution at the eco-evolutionary interface.

Journal Article

High-Density Genome-Wide Association Mapping Identifies Candidate Loci Associated with Maize Stalk Cell Wall Composition.

Maize (Zea mays L.) stalk cell wall composition is a key determinant of forage digestibility, lodging resistance, and biomass utilization efficiency. Although previous genome-wide association studies (GWAS) have identified loci associated with lignin (LIG), cellulose (CEL), and hemicellulose (HC), advances in genomic resources provide an opportunity to revisit existing phenotypic datasets at substantially higher resolution. Here, we re-analyzed a maize association panel consisting of 341 diverse inbred lines using an expanded genotype dataset containing 10.77 million SNPs, two derived compositional indices (CEL/HC and [LIG/(CEL + HC)], and six complementary GWAS models. Across all traits and models, we identified 855 unique significant SNPs associated with 579 candidate genes. Among the traits examined, LIG/(CEL + HC) yielded the greatest number of associations, suggesting that indices representing the relative balance among cell wall components may better capture the genetic architecture of cell wall composition than individual component measurements alone. Integration of multiple GWAS models with functional enrichment, haplotype, and selective sweep analyses prioritized three biologically relevant candidate genes encoding a MYB58 transcription factor, the glycosyltransferase Xt9, and a putative xyloglucan 6-xylosyltransferase. Haplotype analysis revealed significant effects of Xt9 and the xyloglucan 6-xylosyltransferase on cell wall composition, while selective sweep analysis identified Xt9 as a target of repeated selection during maize domestication, ecological adaptation, and modern breeding. Although these candidate genes provide promising targets for future investigation, the associations identified here are based on a single association panel and require functional and independent population validation. Collectively, our results demonstrate how high-density genotyping combined with complementary GWAS models can refine candidate associations and generate testable hypotheses from existing phenotypic datasets.

cell wall composition

Single-cell multi-omics dissects transcript isoform and immune repertoire dynamics in human immunosenescence.

Immunosenescence, a major hallmark of systemic aging, refers to the progressive functional decline of the immune system. This decline not only compromises host defense and immunological memory but also fuels chronic inflammation and tissue degeneration (collectively known as inflammaging). While single-cell RNA sequencing (scRNA-seq) has revealed transcriptomic alterations associated with immune aging, analyses restricted to transcript abundance fail to capture deeper regulatory layers, such as transcript isoform diversity and the remodeling of immune receptor repertoires. To address this limitation, we present a human peripheral immune single-cell multi-omics atlas that integrates gene expression, transcript isoform diversity, and immune receptor repertoires. By combining single-cell full-length transcriptome sequencing (scCycloneSEQ), short-read scRNA-seq, and single-cell immune receptor sequencing (scTCR/BCR-seq), we systematically profiled peripheral blood mononuclear cells (PBMCs) from healthy donors aged 30-40 and 60-70 years. Our analyses uncovered extensive age-related remodeling of immune cell composition, functional states, and TCR/BCR diversity. Notably, we found that CD4+ effector memory T cells exhibited widespread differential isoform usage (DIU), 3'UTR length variation, and a marked reshaping of cytotoxic T lymphocyte (CTL) clonotypes-all of which were closely associated with aging-related inflammation and cellular senescence. This multi-omics atlas delineates key molecular features of immunosenescence and provides a high-resolution resource for deciphering the regulatory architecture underlying immune aging.

TCR/BCR

Chromosome-Level Genome Assembly and Annotation of the Chinese Lizard Gudgeon (Saurogobio dabryi).

The Chinese lizard gudgeon (Saurogobio dabryi) is an economically important freshwater species within the Cyprinidae family, abundant in the middle and lower reaches of the Yangtze River and its adjacent basins. As a promising species suitable for aquaculture in China, the lack of genomic resources has rendered the genetic breeding and conservation research. Here, we present the first chromosome-level genome assembly of S. dabryi using PacBio HiFi long reads, short reads, and Hi-C sequencing data. The final assembly reaches a total size of 1.09 Gb and Hi-C scaffolding anchors 99.55% of the assembled contigs onto 25 chromosomes, with a scaffold N50 reaching 43.15 Mb. The final genome assembly shows a BUSCO completeness of 98.39%. We annotated 659.55 Mb repetitive sequences and 26,036 protein-coding genes, 99.47% of which are functionally annotated. Comparative phylogenomic analysis clarifies the phylogenetic position of Saurogobio within Gobioninae. This high-quality genome provides a critical genetic basis for exploring cyprinid phylogeny, benthic adaptive evolution, genetic improvement, and conservation efforts of S. dabryi.

Saurogobio dabryi

Plasma untargeted metabolomics reveals promising diagnostic metabolites for adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with poor prognosis. Surgery is the only curative option for ACC, but recurrence remains high. Effective systemic therapies are still lacking in ACC. Diagnosis currently relies on integrated hormonal, imaging, and histopathological assessments. However, distinguishing ACC from benign adrenocortical adenoma (ACA) remains challenging. To address this, we performed untargeted plasma metabolomics on patients with ACC and ACA, as well as on healthy controls, to identify differential metabolites and elucidate the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Notably, glycocholic acid emerged as a significantly upregulated metabolite in ACC with superior diagnostic accuracy. Furthermore, a metabolic model incorporating six plasma metabolites, including glycocholic acid, distinguished ACC from ACA and healthy controls with an area under the curve (AUC) of 0.9266. These findings demonstrate that plasma metabolomics might serve as a promising tool for the detection of ACC.

adrenocortical carcinoma

Rapid glycomic analysis of serum EVs reveals altered N-glycosylation patterns in ASD.

Objective laboratory diagnostics for autism spectrum disorder (ASD) are lacking, necessitating rapid clinical screening tools. Because serum extracellular vesicle (EV) N-glycosylation captures critical neurodevelopmental signatures, we developed a fast, biologically interpretable diagnostic strategy. EVs from ASD patients with language impairment and neurotypical controls were isolated using a rapid extra-polyethylene glycol precipitation/filtration (EPF) workflow, benchmarked against ultracentrifugation. Following MALDI-TOF/MS profiling, machine learning was re-evaluated using repeated nested cross-validation to reduce optimistic bias and potential information leakage. Among five classifiers, Random Forest (RF) showed the best overall balance across discrimination, calibration, and classification metrics. RF-based SHAP analysis provided transparent interpretation, highlighting key discriminative glycans, including H4N3S1F1, H5N5S1F1, and H3N5F1. To elucidate molecular mechanisms, we integrated public EV transcriptomic data. This revealed significant dysregulation of N-glycosylation machinery genes (e.g., MAN1A1, NEU1, OSTC, RPN2), whose expression directionally aligned with observed glycan shifts in synaptic pathways. Collectively, this rapid serum EV N-glycomic workflow, combined with leakage-controlled RF-based interpretation, provides a promising foundation for non-invasive ASD biomarker discovery and future multicenter validation.

Humans

ATF4-histone 2-hydroxyisobutyrylation feedback loop drives sepsis-induced inflammation.

BACKGROUND AND PURPOSE: The role and mechanisms of lysine 2-hydroxyisobutyrylation (Khib) in the acute inflammatory phase of sepsis remain unclear. We investigated the function and underlying mechanisms of histone H4 lysine 5 2-hydroxyisobutyrylation (H4K5-hib) in sepsis-induced inflammation in vivo and in vitro. EXPERIMENTAL APPROACH: Acute sepsis was induced by caecal ligation and puncture (CLP) in mice, and inflammatory responses were modelled in lipopolysaccharide (LPS)-stimulated macrophages. CUT&Tag-seq was used to identify genomic targets associated with H4K5-hib and activating transcription factor 4 (ATF4). Immunofluorescence, Western blotting, qPCR, dual-luciferase assays, and ELISA were performed to investigate the underlying mechanisms. KEY RESULTS: H4K5-hib levels were increased in macrophages during the acute inflammatory phase of sepsis. LPS stimulation enhanced H4K5-hib enrichment at the ATF4 promoter, thereby promoting ATF4 transcription. Inhibition of EP300-mediated 2-hydroxyisobutyrylation or mutation of H4K5 abolished ATF4 activation. Increased H4K5-hib activated the ATF4/NLRP3 signalling axis, promoting inflammasome assembly and amplifying inflammatory responses. ATF4 directly bound to the EP300 promoter and enhanced its transcription, forming a positive feedback loop that further increased H4K5-hib levels. In CLP-induced sepsis, pharmacological inhibition of EP300 or ATF4 reduced H4K5-hib levels and suppressed NLRP3 inflammasome activation. CONCLUSION AND IMPLICATIONS: These findings reveal a previously unrecognized epigenetic mechanism underlying sepsis-induced inflammation and identify the EP300/ATF4/H4K5-hib positive feedback loop as a potential therapeutic target for sepsis.

Animals

Evaluation of intravenous sedation in dental implant surgeries: A prospective cohort study.

PURPOSE: This study aimed to evaluate the impact of intravenous sedation on patient-centered outcomes during implant and bone augmentation surgeries. METHOD: A prospective observational cohort study included 40 patients undergoing placement of &#x2265;3 implants, with or without bone augmentation. Patients underwent surgery under either intravenous sedation (n = 20) or local anesthesia alone (n = 20), according to routine clinical decision-making and patient preference. The sedation group received intravenous sedation with a multimodal regimen comprising remimazolam, dexmedetomidine, alfentanil, and low-dose esketamine, whereas the control group received local anesthesia only. Patient-reported outcome measures, hemodynamic parameters (SBP, DBP, HR, SpO2), postoperative pain (0-10 scale), and OHRQoL (OHIP-14) were recorded from baseline through 7 days post-surgery. RESULTS: Intravenous sedation was associated with significantly lower intraoperative pain (0.5 [IQR: 0&#x223c;2.75] vs. 3.25 &#xb1; 2.40, p = 0.003), anxiety (1 [IQR: 0&#x223c;2.75] vs. 4 [IQR: 3&#x223c;6], p = 0.001), and experienced discomfort (2 [IQR: 1&#x223c;3.75] vs. 4.15 &#xb1; 2.16, p = 0.016), and shortened perceived treatment duration (2.90 &#xb1; 2.34 vs. 5 [IQR: 4&#x223c;5], p = 0.020). Early postoperative pain was lower in the sedation group from Days 1-4 (p = 0.003-0.010). Hemodynamic parameters were more stable under sedation, with lower SBP (116.42 &#xb1; 13.32 vs. 144.11 &#xb1; 17.42 mmHg, p < 0.001), DBP (73.21 &#xb1; 10.28 vs. 82.37 &#xb1; 11.03 mmHg, p = 0.012), and HR (71.00 [IQR: 62.50&#x223c;79.25] vs. 85.00 &#xb1; 10.72 bpm, p = 0.021). OHRQoL scores favored the sedation group in swallowing, diet, malaise, and daily activities, particularly during the first three postoperative days (p=0.006-0.040). CONCLUSION: Intravenous sedation may enhance the patient experience during implant and/or bone augmentation procedures by reducing intraoperative pain and anxiety, improving hemodynamic stability, and promoting better early-postoperative recovery and OHRQoL. These findings suggest that intravenous sedation provides a safe and effective alternative for implant dentistry surgery, particularly for anxious or pain-sensitive individuals.

Humans

Multi-omics Approaches to CCAAT/Enhancer-Binding Protein Beta in Oral Squamous Cell Carcinoma: Crosstalk Between Tumor Cells and Tumor-Associated Macrophages Driving Disease Progression.

BACKGROUND: CCAAT/Enhancer-Binding Protein Beta (CEBPB) is an important transcription factor that regulates tumor progression. However, the mechanism by which CEBPB regulates the progression of Oral Squamous Cell Carcinoma (OSCC) remains incompletely understood. Tumor progression depends on complex intercellular interactions within the tumor microenvironment. The purpose of this study was to investigate the role and epigenetic regulatory mechanisms of CEBPB in interactions between OSCC cells and tumor-infiltrating immune cells. METHODS: Bulk RNA-seq, ChIP-seq, and scRNA-seq data were obtained from The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database. The HOMER algorithm was employed to identify enhancers and predict the CEBPB-binding motif. Cell cluster analysis, functional enrichment, and intercellular interaction analysis were performed using the "Seurat" R package. H3K27ac enrichment at GAS6 enhancers was validated by ChIP-qPCR. Metastatic OSCC cells with CEBPB knockdown or GAS6 overexpression were established and co-cultured with THP-1 cells. IL-10 and IL-6 secretion from co-cultured THP-1 cells was detected via ELISA. Chemotaxis of OSCC cells toward THP-1 cells was assessed through a Transwell assay. RESULTS: CEBPB was upregulated in OSCC and correlated with poor prognosis. By integrating H3K27ac ChIP-seq and bulk RNA-seq data, 131 CEBPB-regulated enhancer-controlled genes were identified in lymph node metastatic OSCC cells. scRNA-seq analysis revealed eight major cell clusters in primary foci and lymph node metastases, including T/NK cells, malignant epithelial cells, B/plasma cells, macrophages, fibroblasts, dendritic cells, endothelial cells, and mast cells, with the malignant epithelial cells stratified into distinct sub-clusters. CEBPB expression was elevated in malignant epithelial cells of lymph node metastases compared to primary foci. Furthermore, 15 pairs of enhanced ligand-receptor interactions were identified in lymph node metastases relative to primary foci. GAS6 was a CEBPB-regulated enhancer-controlled gene, primarily mediating interactions between malignant cells and macrophages. CEBPB knockdown in metastatic OSCC cells significantly impaired their chemotaxis toward cocultured THP-1 cells, and downregulated IL-10/IL-6 secretion and CD206 expression in cocultured THP-1 cells. Conversely, GAS6 overexpression reversed these inhibitory effects. CONCLUSION: CEBPB activated GAS6 transcription in metastatic OSCC cells. The CEBPB/ GAS6 axis in metastatic OSCC cells enhanced their chemotaxis toward macrophages and promoted the M2 polarization of macrophages, thereby facilitating the establishment of an immunosuppressive microenvironment.

Humans

Genome-Wide Analysis of the AT-Hook Gene Family in Malus sieversii and Functional Characterization of MsAHL13.

AT-hook motif nuclear-localized (AHL) proteins are pivotal in plant growth, development, and stress responses. Nevertheless, there is limited research on AHL proteins in Malus sieversii. Our study identified 25 AHL genes from the M. sieversii genome, named MsAHL1-MsAHL25. The encoded protein sequences had lengths ranging from 195 to 554 amino acids, molecular weights from 19.17 to 58.53 kDa, and isoelectric points from 4.67 to 10.09. Chromosomal mapping revealed that these 25 genes were unevenly distributed across 10 chromosomes. Collinearity analysis of AHL genes in M. sieversii implied that gene loss might have occurred during its evolution. The phylogenetic tree classified the AHL proteins of M. sieversii into two subfamilies, showing a close relationship with multiple proteins of M. domestica. Promoter analysis indicated that the AHL genes in M. sieversii harbored numerous stress- and hormone-responsive elements, suggesting their potential role in various stress responses. qRT-PCR analysis of six representative MsAHLs under biotic and abiotic stresses demonstrated that the expression of MsAHL13, MsAHL15, and MsAHL17 was significantly upregulated under salt, drought, and cold stresses, while MsAHL01 expression was inhibited under low-temperature stress. All six MsAHLs were induced by the pathogen Valsa mali. Subcellular localization analysis of the specifically expressed protein MsAHL13 showed its nuclear location. Furthermore, luciferase and yeast two-hybrid assays confirmed the in vitro physical interaction between the MsAHL13 and MsMYB1 proteins. This research offers an important theoretical basis for further exploration of the functional mechanisms of this gene family in responding to environmental stresses.

Malus sieversii

Development of Microsatellite Marker System to Determine the Genetic Diversity of Experimental Chicken, Duck, Goose, and Pigeon Populations.

Poultries including chickens, ducks, geese, and pigeons are widely used in the biological and medical research in many aspects. The genetic quality of experimental poultries directly affects the results of the research. In this study, following electrophoresis analysis and short tandem repeat (STR) scanning, we screened out the microsatellite loci for determining the genetic characteristics of Chinese experimental chickens, ducks, geese, and pigeons. The panels of loci selected in our research provide a good choice for genetic monitoring of the population genetic diversity of Chinese native experimental chickens, ducks, geese, and ducks.

Animals