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Biomedical subjects

Zhen Li

Publications and source records attributed to Zhen Li.

6 recordsLinked to original sources

Unraveling epigenetic and genetic variations in response to cold stress in two lotus ecotypes.

Genetic variations accumulate over long evolutionary timescales, whereas epigenetic modifications can arise rapidly and be inherited across generations. However, the interplay between genetic and epigenetic variations in shaping ecotype-specific phenotypic plasticity remains elusive. Focusing on two lotus ecotypes that evolved under distinct winter temperature regions and display divergent annual growth cycles under cold stress, we generated DNA methylation landscapes across three sequence contexts (CG, CHG, and CHH, where H = A, T, or C) and identified single-cytosine methylation polymorphisms (SMPs) and single-nucleotide polymorphisms (SNPs). Interestingly, only CG methylation patterns mirror population-level genetic variations. Using epigenetic genome-wide association analysis, we identified differentially methylated CG sites that are either cis- or trans-regulated by SNP. Notably, we constructed a multifactorial regulatory network centered on the NnMKK4-NnCYCD5 module, linking cold response with cell cycle regulation. Temperature stress experiments conducted on lotus ecotypes and transgenic Arabidopsis (OE-NnMKK4 and OE-NnCYCD5) confirmed that NnMKK4 acts as a cold receptor and that NnCYCD5 promotes cell cycle progression and growth under cold conditions. Collectively, our findings provide novel insights into the co-evolutionary dynamics of epigenetic and genetic variations that are associated with different growth cycles of lotus ecotypes in response to cold stress.

DNA methylation

Development and validation of a serum peptidomic signature for early detection of asymptomatic ovarian cancer: A multi-center prospective study.

Early detection of asymptomatic ovarian cancer (asym-OC) remains a critical challenge, the failure of which underlies its high mortality. Performing serum peptidomic profiling of 843 participants in the cohort SOCFCP, we distill 1,081 initial features into a 7-marker panel for asym-OC detection via a biology-informed machine-learning (ML)-based feature selection strategy. Three markers significantly revert toward non-OC levels after surgery. Integrating the panel with age, CA125, and HE4, we develop and externally validate (n = 159) a LightGBM model, ProMS+. For early-stage OC detection, ProMS+ shows a specificity of 92.6% at 95.0% sensitivity, outperforming CA125 (44.7%), HE4 (11.2%), and Risk of Ovarian Malignancy Algorithm (ROMA) (24.0%), with an area under the curve (AUC) of 0.993. In a simulated high-risk population (n = 100,000; OC prevalence = 1%), ProMS+ yields a high AUC (0.983) and a higher positive predictive value than CA125, HE4, and Age + CA125 + HE4 combined model (0.201 vs. 0.027, 0.090, and 0.064). ProMS+ offers a promising, non-invasive, and interpretable approach for the early detection of asym-OC.

Humans

Skin-innervating glutamatergic neurons modulate aging.

Peripheral nerves regulate skin homeostasis by secreting neurotransmitters, but their role during skin aging remains incompletely understood. Here, we report that cutaneous denervation accelerates skin aging, as evidenced by collagen reduction. Neurofilament heavy chain (Nefh) is decreased in aged skin and is predominantly expressed in vesicular glutamate transporter 2-positive (Vglut2+) skin-innervating glutamatergic neurons. Notably, dermal fibroblasts, the primary producers of collagen, frequently contact Nefh+ nerve fibers. Moreover, Nefh deletion in Vglut2+ glutamatergic neurons drives skin fibroblast senescence and collagen loss, whereas additional glutamate improves skin aging phenotypes. Mechanistically, cyclin-dependent kinase 5 (Cdk5) interacts with both Nefh and Vglut2 and maintains glutamate release and collagen homeostasis. Additionally, in skin fibroblasts, solute carrier family 1 member 3 (Slc1a3) governs the collagen-promoting and anti-senescence functions of glutamate. Together, these findings reveal Nefh-mediated glutamatergic neuromodulation of skin aging and provide therapeutic targets for aging-related skin disorders.

Animals

A pan-cancer single-cell atlas uncovers the role of sex hormones and chromosomes in sex-divergent reprogramming of the tumor microenvironment.

BACKGROUND: Sex bias is pervasive in tumors; however, how sex chromosomes and hormone-responsive signaling shape the tumor microenvironment (TME) remains insufficiently characterized. Considering the critical impact of the TME on tumor progression and response to immunotherapy, a pan-cancer investigation of sex-specific and cancer-context-dependent TME features is warranted. METHOD: Based on stringent inclusion criteria, we constructed a high-resolution pan-cancer single-cell sequencing atlas by integrating 31 publicly available single-cell RNA-seq datasets, comprising a total of 1,831,436 cells by integrating 468 samples from eight types of non-sex-specific solid tumors (282 males and 186 females). After correcting for batch effects, we identified major and minor cellular subsets. Multiple computational approaches were applied to investigate sex-associated differences in cellular composition, gene expression, pathway activity, malignant cell states and intercellular communication. RESULTS: We systematically compared sex-specific TME features across eight common solid malignancies. Male-biased CD8+ T cell exhaustion emerged as a recurrent but non-uniform feature, with its magnitude varying across cancer types and being modified by tissue-specific contexts. This pattern was associated with androgen-response signature scores and expression-based loss of the Y chromosome (LOY) scores. M2-like macrophage polarization showed a more cancer-type-dependent pattern; although female-biased enrichment was observed in selected malignancies, it did not represent a uniform pan-cancer feature. Expression-based X chromosome inactivation (XCI)/XCI escape-related programs, estrogen-response signature scores and stromal components, including fibroblasts and endothelial cells, were associated with macrophage and immune-regulatory states in specific tumor contexts. Tumor cells of male origin displayed higher genomic instability and more aggressive phenotypes, with androgen-response signatures and LOY contributing to the development of a male biased malignant state. Furthermore, expression-based LOY scores in malignant cells were associated with CD8+ T cell exhaustion based on transcriptomic proxies. CONCLUSION: Our study uncovers extensive but heterogeneous sex-specific differences in the TME across multiple cancer types. We propose a regulatory framework linking sex chromosomes, hormone-responsive signaling and TME interactions, which is consistent with recurrent male-biased CD8⁺ T cell exhaustion and context-dependent M2-like macrophage polarization. Importantly, the magnitude and, in some cancers, the direction of these sex-biased features are modified by tissue-specific contexts. These findings underscore the need to include sex chromosome and hormone status as essential biological variables in studies of the tumor microenvironment and the design of immunotherapies.

Tumor Microenvironment

Icaritin Sensitizes Hepatocellular Carcinoma to PD-L1 Therapy by NQO1-Dependent Ferroptosis Induction.

Hepatocellular carcinoma (HCC) remains challenging with limited immunotherapy response. Despite its clinical promise in advanced HCC, the mechanisms of icaritin, especially concerning ferroptosis induction and immune modulation, remain elusive. This study aims to determine if the antitumor effect of icaritin involves the induction of ferroptosis via NAD(P)H quinone oxidoreductase 1 (NQO1) and if it can augment the efficacy of programmed cell death 1 ligand 1 (PD-L1) therapy by potentiating natural killer (NK) cell activity. Using human HCC cell lines (Huh7, Hep3B, PLC/PRF/5, SNU-449, and MHCC97-H) and two synergistic mouse models (Hepa1-6 and SgPten/c-Met), we examined icaritin's inhibition of tumor growth and induction of ferroptosis via the NQO1 pathway, monitoring key markers (reactive oxygen species [ROS], glutathione peroxidase 4 [GPX4], ferritin heavy chain 1 [FTH1]). The NQO1 inhibitor dicoumarol was employed to validate the pathway. Tumor microenvironment (TME) remodeling was assessed through cancer-associated fibroblasts (CAFs) markers and immune cell profiling, focusing on NK cell infiltration. Combination therapy with anti-PD-L1 was tested in vivo. Icaritin significantly inhibited HCC growth in vitro and in vivo. Its antitumor effect was mediated by NQO1-mediated ferroptosis, via elevated ROS, diminished mitochondrial membrane potential, and downregulated GPX4 and FTH1. Analysis of The Cancer Genome Atlas (TCGA) data revealed that NQO1 is overexpressed in human HCC tissues. Icaritin enhanced NK cell infiltration while reducing CAF abundance and suppressing recombinant focal adhesion kinase (FAK) and discoidin domain receptor 1 (DDR1) signaling. Notably, icaritin synergized with anti-PD-L1 therapy to enhance tumor suppression without increasing toxicity, correlating with potentiated NK cell immunity. Our findings demonstrate that icaritin triggered NQO1-mediated ferroptosis and remodeled TME to enhance NK cell recruitment and PD-L1 therapy efficacy. This provides rationale for evaluating icaritin-based combination immunotherapy in HCC through dual action on ferroptosis and NK cell activation.

Ferroptosis

Uncovering encrypted antimicrobial peptides in health-associated Lactobacillaceae by large-scale genomics and machine learning.

BACKGROUND: Antimicrobial peptides (AMPs) are well known for their broad-spectrum activity and have shown great promise in addressing the antibiotic-resistant crisis. The Lactobacillaceae family, recognized for its health-promoting effects in humans, represents a valuable source of novel AMPs. However, the global prevalence and distribution of AMPs within Lactobacillaceae remains largely unknown, which limits the efficient discovery and development of novel AMPs. RESULTS: We analyzed all available genomes (10,327 genomes), encompassing 38 genera and 515 species, to investigate the biosynthetic potential (indicated by the number of AMP sequences in the genome) of AMP in the Lactobacillaceae family. We demonstrated Lactobacillaceae species had ubiquitous (69.90%) biosynthetic potential of AMPs. Overall, 9601 AMPs were identified, clustering into 2092 gene cluster families (GCFs), which showed strong interspecies specificity (95.27%), intraspecies heterogeneity (93.31%), and habitat uniqueness (95.83%), that greatly expanded on the AMP sequence landscape. Novelty assessment indicated that 1516 GCFs (72.47%) had no similarity to any known AMPs in existing databases. Machine learning predictions suggested that novel AMPs from Lactobacillaceae possessed strong antimicrobial potential, with 664 GCFs having an additive minimum inhibitory concentration (MIC) below 100&#xa0;&#x3bc;M. We randomly synthesized 16 AMPs (with predicted MIC&#x2009;<&#x2009;100&#xa0;&#x3bc;M) and identified 10 AMPs exhibiting varied-spectrum activity against 11 common pathogens. Finally, we identified one Lactobacillus delbrueckii-originated AMP (delbruin_1) having broad-spectrum (all 11 pathogens) and high antimicrobial activity (average MIC&#x2009;=&#x2009;38.56 &#xb5;M), which proved its potential as a clinically viable antimicrobial agent. CONCLUSIONS: We uncovered the global prevalence of AMPs in Lactobacillaceae and proved that Lactobacillaceae is an untapped and invaluable source of novel AMPs to combat the antibiotic-resistance crisis. Meanwhile, we provided a machine learning-guided framework for AMP discovery, offering a scalable roadmap for identifying novel AMPs not only in Lactobacillaceae but also in other organisms. Video Abstract.

Machine Learning