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Single-cell RNA sequencing reveals disease associated changes in brain endothelial cells in the 5XFAD mouse.

Vascular dysfunction is a key contributor to Alzheimer’s disease (AD) pathology, where changes to the endothelium and its crucial role in maintaining blood-brain barrier (BBB) integrity have been of particular emphasis. The transgenic 5XFAD (5X Familial Alzheimer’s Disease) mouse model, which exhibits AD-related amyloidosis through FAD associated mutations in amyloid precursor protein (APP) and presenilin-1 (PS1), has become a widely adopted preclinical model in AD-related research studies. The need for cross-study standardization, accessibility, and data reproducibility has led to the widespread implementation of the C57BL/6J genetic background for maintaining this model. However, its reliability for studying vascular dysfunction and BBB alterations has been questioned due to conflicting reports in the literature. This variation is often attributed to the previously documented protective nature of the C57BL/6J background and loss of genetic background diversity. Since prior studies have mostly relied on imaging or functional assays, we herein utilized single-cell RNA sequencing (scRNAseq) to investigate AD-related molecular changes to endothelial cell populations in the 5XFAD mouse model. To initially build this resource, we focused on 12-month-old male mice, which revealed differentially expressed genes between 5XFAD and wildtype animals that mapped to signaling pathways involved in DNA damage, immune reactivity, and inflammation, among others. Many of these transcriptomic changes were zonated along the arteriovenous axis and occurred in AD genome-wide association study (GWAS) risk-associated genes. Overall, we anticipate this resource will help clarify the use of the 5XFAD model for studying AD-associated vascular changes and provide the foundation for expanded molecular profiling of brain endothelial cells under AD-associated conditions.

Animals

Nuclear RNA sequences coding for alpha and beta globins in erythroid cells: evidence for multiple intermediate molecules.

The poly (A)-containing nuclear RNA from dimethylsulfoxide-induced Friend leukemia cells was fractionated by acrylamide gel electrophoresis in denaturing conditions and analyzed for alpha and beta globin RNA sequences. The results indicate that nuclear RNA contains one species of large-size RNA (0.6 X 10(6) daltons), which is the putative precursor for beta globin mRNA only. In addition, it was shown by electrophoretic analysis that the complex of RNA molecules not resolved by sucrose gradient centrifugation (11S) comprises sequences of decreasing size (0.34, 0.28, and 0.26 X 10(6) daltons), which might be the precursors of alpha and beta globin mRNA.

Erythrocytes

Quantitative analysis of the rescue of RNA sequences by mammalian type C viruses.

The specificity and quantitation of the rescue of RNA sequences by mammalian type C viruses has been investigated. Type C virus can package with specificity only type C viral RNA. Type C viruses do not encapsidate with comparable efficiency either type B viral or cellular globin mRNA. Conversely, a non-type C mammalian retravirus, MP-MV, cannot encapsidate type C RNA. A revertant of Kirsten sarcoma virus (Ki-SV)-transformed nonproducer cells which fails to rescue biologically active Ki-SV after superinfection with helper virus had no detectable intracellular Ki-SV-specific RNA. The results suggest specific mechanisms by which type C viral proteins can package type C viral RNA and provide an approach to classifying RNA of potentially defective endogenous retraviruses as type C in origin.

Base Sequence

Unveiling tumor heterogeneity by single cell RNA-sequencing: From basic considerations to clinical applications.

Tumor heterogeneity-encompassing diverse cellular phenotypes, genomic alterations, and microenvironmental contexts-is a principal barrier to effective cancer therapy. Single-cell RNA sequencing (scRNA-seq) has transformed our ability to resolve this complexity by capturing transcriptomes at single-cell resolution. Here, we review the technical foundations required for high-quality scRNA-seq studies. We then trace the evolution of scRNA-seq platforms from manual micromanipulation to high-throughput systems, and describe the computational pipelines that enable reliable data interpretation. The application of scRNA-seq is exemplarily shown in the context of lung cancer, where single-cell profiling has revealed (i) the clonal and sub-clonal architecture of tumors, (ii) extensive remodeling of the immune microenvironment, iii) key mechanisms underlying resistance to targeted agents and immune-checkpoint blockade, and (iv) the dynamics of neo-antigen-specific T-cell responses. Integrating machine-learning techniques-such as deep-learning classifiers and graph-based models-with single-cell transcriptomic data has markedly sped up biomarker discovery, produced more accurate risk-stratification scores, and enabled the generation of patient-specific therapeutic predictions. We surveyed the major trial registry ClinicalTrials.gov and identified ∼380 ongoing or completed studies that explicitly incorporate scRNA-seq as a correlative or pharmacodynamic endpoint. Overall, the analysis shows that scRNA-seq becomes an increasingly important component of modern trials, providing high-resolution cellular and molecular readouts that complement conventional imaging and bulk-omics endpoints. While key challenges remain, ranging from costs, scalability and need for rigorous validation before routine clinical deployment, ongoing technological advances continue to expand the potential of scRNA-seq as a cornerstone of precision medicine.

Humans

Autodegradation of pre-mRNA containing nuclear ribo-nucleoprotein particles. The effect of autodegradation on the double-stranded RNA sequences and on the protein composition of particles.

The quantitative changes of double-stranded RNA components of nuclear ribonucleo-protein particles containing pre-mRNA was investigated in the course of incubation of particles at 37 degrees C. The incubation of purified nuclear particles revealed the fragmentation of long double-stranded RNA sequences into shorter stretches. The presence of nuclear sap in the incubation mixture resulted in degradation of the double-stranded RNAs into acid soluble products. Autodegradation and/or ribonuclease treatment of nuclear RNP particles is accompanied by quantitative changes in the minor protein constituents of informofer.

Animals

Functional phenotyping of genomic variants using joint multiomic single-cell DNA-RNA sequencing.

Genetic variants (both coding and noncoding) can impact gene function and expression, driving disease mechanisms such as cancer progression. The systematic study of endogenous genetic variants is hindered by inefficient precision editing tools, combined with technical limitations in confidently linking genotypes to gene expression at single-cell resolution. We developed single-cell DNA-RNA sequencing (SDR-seq) to simultaneously profile up to 480 genomic DNA loci and genes in thousands of single cells, enabling accurate determination of coding and noncoding variant zygosity alongside associated gene expression changes. Using SDR-seq, we associate coding and noncoding variants with distinct gene expression in human induced pluripotent stem cells. Furthermore, we demonstrate that in primary B cell lymphoma samples, cells with a higher mutational burden exhibit elevated B cell receptor signaling and tumorigenic gene expression. SDR-seq provides a powerful platform to dissect regulatory mechanisms encoded by genetic variants, advancing our understanding of gene expression regulation and its implications for disease.

Humans

Bayesian Phylogenetic Lineage Reconstruction with Loss of Heterozygosity Mutations Derived from Single-Cell RNA Sequencing.

Mutations are acquired frequently, such t`hat each cell's genome inscribes its history of cell divisions. Loss of heterozygosity (LOH) accumulates throughout the genome, offering large encoding capacity for phylogenetic inference of cell lineage.In this chapter, we demonstrate a method, using single-cell RNA sequencing, for reconstructing cell lineages from inferred LOH events in a Bayesian manner, annotating the lineage with cell phenotypes, and marking developmental time points based on X-chromosome inactivation. This type of retrospective analysis could be incorporated into scRNA-seq pipelines and was initially developed to investigate Emx1+ cortical projection neuron and glia lineages from C57Bl/6J (B6) and CAST/EiJ (CA) interstrain F1 mice, describing progenitor cells giving rise to multiple cortical cell types through stereotyped expansion and distinct waves of neurogenesis.

Animals

Polygenic enrichment analysis in multi-omics levels identifies cell/tissue specific associations with schizophrenia based on single-cell RNA sequencing data.

OBJECTIVE: Understanding the specific cellular origin and tissue heterogeneity in schizophrenia is critically important for exploring the disease etiology. This study aims to investigate these aspects by performing multiple analyses based on omics data. METHOD: We performed single-cell disease relevance score (scDRS) algorithm to link brain single-cell RNA sequencing (scRNA-seq) with schizophrenia risk across multi-omics scales at single-cell resolution. This approach identified cell types with overexpression of schizophrenia-related genes implicated by multi-omics panels (ATAC-seq, RNA-seq, TWAS, and GWAS). Schizophrenia-related genes from these multi-omics panels were extracted and combined with scRNA-seq data to calculate scDRS. Subsequently, the cell-type vs. disease association and tissue heterogeneity were assessed using scDRS for each omics panel. RESULTS: We identified two novel cell subpopulations in the brain that differentially express SCUBE3 (59 cells, 7.0 %) and FN1 (21 cells, 2.5 %). At the individual cell level, schizophrenia-associated cell subpopulations included microglial cell associated with ATAC-seq panel (Passociation = 0.002, Pheterogeneity = 0.009) and deep layer neuron suggestively associated with GWAS panel (Passociation = 0.033, Pheterogeneity = 0.017). At the brain tissue level, microglial cell was significantly associated with cortical plate in ATAC-seq panel (Passociation = 0.002, Pheterogeneity = 0.011). Gene level analysis identified several genes associated with schizophrenia across multi-omics panels. CONCLUSIONS: Our study outlines the signature of cell subpopulations, brain regions, and disease risk genes in schizophrenia at single-cell resolution across multi-omics scales. These findings provide a reference for future precision medicine approaches targeting specific cell types and brain regions in schizophrenia.

Schizophrenia

Analysis of ferroptosis-related genes in cerebral ischemic stroke via immune infiltration and single-cell RNA-sequencing.

Ischemic stroke (IS) represents a harmful neurological disorder with limited treatment options. Ferroptosis accounts for the iron-dependent, nonapoptotic cell death pattern, which shows the feature of fatal lipid ROS accumulation. Nonetheless, ferroptosis-related biomarkers for identifying IS early are currently lacking. The present study focused on investigating the possible ferroptosis-related biomarkers for IS and analyzing their effects on immune infiltration. Altogether five hub differentially expressed ferroptosis-related genes (DEFRGs) were identified from the relevant databases. Additionally, single-cell RNA-sequencing (seq) analysis was conducted for the comprehensive mapping of cell populations based on the IS database. These five hub DEFRGs were analyzed using gene set enrichment analysis, miRNA prediction, and single-cell RNA-seq analysis. A transient middle cerebral artery occlusion mouse model was constructed. We also adopted bioinformatics methods combined with western blot, changes to mitochondria, hematoxylin & eosin staining, Nissl staining, ROS fluorescence staining, immunohistochemistry, and quantitative real-time polymerase chain reaction (qRT-PCR) to show the involvement of ferroptosis in IS progression. The results revealed that nuclear factor erythroid-derived 2-like 2 (Nfe2l2) was the potential candidate biomarker for IS diagnosis, and ferroptosis may be suppressed via the Nfe2l2/HO-1 pathway. Thus, drug targeting Nfe2l2 can shed novel lights on IS treatment.

Ferroptosis

Specific RNA sequences and gene products of MC29 avian acute leukemia virus.

The 28S RNA of the defective avian acute leukemia virus MC29 contains two sets of sequences: 60% are hybridized by DNA complementary to other avian tumor virus RNAs (group-specific cDNA) and 40% are hybridized only by MC29-specific cDNA. Specific and group-specific sequences of viral RNA, defined in terms of their large RNase T(1)-resistant oligonucleotides, were located on a map of all large T(1) oligonucleotides of viral RNA. Oligonucleotides representing MC29-specific sequences of viral RNA mapped between 0.4 and 0.7 unit from the 3'-poly(A) end. Oligonucleotides of group-specific sequences mapped between 0 and 0.4 and between 0.7 and 1 map unit. Cell-free translation of viral RNA yielded three proteins with approximate molecular weights of 120,000, 56,000, and 37,000, termed P120(mc), P56(mc), and P37(mc). P120(mc) contained both MC29-specific peptides and serological determinants and peptides of the conserved, internal group-specific antigens of avian tumor viruses. P120(mc) is translated only from full-length 28S RNA. Furthermore, MC29 RNA contains sequences related to the group-specific antigen gene (gag), near the 5' end, which are followed by MC29-specific sequences. We conclude that this protein is translated from the 5' 60% of the RNA, and that it includes a segment translated from the specific sequences. It is suggested that the transforming (onc) gene of MC29 may consists of the specific and some group-specific RNA sequences and that P120(mc), which is also found in transformed cells, may be the onc gene product.

Avian Leukosis Virus

Transcriptome-Wide Analysis of the 5' Cap Status of RNA Using 5' Monophosphate-Dependent Exonuclease Digestion and RNA Sequencing.

Eukaryotic mRNAs carry an N7-methylguanosine (m7G) cap structure at their 5' extremity, which protects them from the degradation by 5'-3' exoribonucleases and plays a pivotal role in mRNA metabolism, promoting splicing, nuclear export, and translation. Decapping, the enzymatic process that removes this structure, is a key event during cytoplasmic mRNA 5'-3' decay, leading to the degradation of the transcript body by Xrn1. In this chapter, we describe a procedure to assess the cap status of RNA at the transcriptome level. It is based on a treatment of total RNA extracts with a 5' monophosphate-dependent exonuclease, which like Xrn1 specifically degrades decapped RNAs harboring 5' monophosphate extremities, but not RNAs with intact m7G cap. The digested RNAs are then analyzed by RNA sequencing.

Exoribonucleases

Cell-type-specific response to silicon treatment in soybean leaves revealed by single-nucleus RNA sequencing and targeted gene editing.

Mineral nutrient uptake and deposition profoundly influence plant development, stress resilience, and productivity. Silicon (Si), though classified as a non-essential element, significantly influences a plant's physiology, particularly in fortifying defense responses and mitigating stress. While the genetic and molecular mechanisms of Si uptake and transport are well studied in monocots, particularly rice, their role in dicot species, such as soybean, remains unclear at the cellular and molecular levels. In this study, we utilized single-nucleus RNA sequencing (snRNA-seq) to dissect cellular responses to Si accumulation in soybean leaves. We identified distinct cellular populations, including a unique Si-induced or Si-associated cell cluster within vascular cells, suggesting a specialized mechanism of Si distribution. Si treatment notably induced the expression of defense-related genes, with a pronounced enrichment in vascular cells, underscoring their pivotal role in activating plant defense mechanisms. Moreover, Si modulated the expression of genes involved in phytoalexin biosynthesis, salicylic acid, and immune receptor signaling, suggesting transcriptional priming of genes involved in defense responses. Further investigation of Si transporters revealed precise expression of an Si efflux gene in epidermal cells in response to Si treatment. We also validated the role of efflux Si transporters using a Xenopus oocyte assay and CRISPR/Cas9 genome editing of composite soybean plant roots. This study provides critical insights into the biotic stress regulatory networks influenced by Si treatment in soybean leaves at the single-cell level, thus laying the foundation for enhancing stress tolerance through optimized mineral nutrient uptake.

Glycine max

Integrated bulk and single-cell RNA sequencing reveals a prognostic neuro-mimicry signature in papillary thyroid carcinoma.

BACKGROUND: Cancer cells can acquire neuron-like characteristics ("neural mimicry") to promote progression. However, the role of specific ion channel genes in Papillary Thyroid Carcinoma (PTC) and their clinical significance remains unclear. METHODS: We included transcriptomic data from 521 PTC patients in the TCGA cohort. A neuron-specific gene set was used to screen for potential targets. We constructed a prognostic model using LASSO logistic regression. To verify the cellular origin of the signature, we performed single-cell RNA sequencing (scRNA-seq) analysis on the GSE184362 dataset. RESULTS: We established an 8-gene signature involving KCNN4, KCNN1, KCNT2, SNAP25, KCNK16, GABRG1, GABRG2, and GABRB2. The model demonstrated good predictive performance for lymph node metastasis, with an AUC of 0.721 (95% CI 0.677-0.765). Single-cell analysis of seven integrated tumor samples (N = 65,744 cells) confirmed that GABRB2 was specifically enriched in malignant thyrocytes (EPCAM+/KRT18+) at 200-fold higher detection rates than immune cells (20.0% vs. 0.1%, P ≈ 0), supporting tumor-intrinsic neural mimicry. High-risk patients showed immunosuppressive features with altered immune cell infiltration patterns. CONCLUSION: This study identifies a malignant cell-intrinsic signature for predicting PTC prognosis. Validated by single-cell data, our findings suggest that targeting ion channels may represent a potential therapeutic strategy for modulating neuro-immune interactions in thyroid cancer, pending experimental validation.

GABRB2

An improved rapid enzymatic method of RNA sequencing using chemical modification.

A version of rapid gel sequencing procedure based on the analysis of partial endonuclease hydrolizates of chemically modified 5'-32P-labelled RNA is suggested. Complete and selective modification of cytidilic residues by a methoxyamine-bisulfite mixture leads to the unfolding of the RNA secondary structure and, due to this effect, to the generation of a more uniform set of fragments after partial RNAase hydrolysis. The position of cytidines in an RNA sequence can be determined by restricting the hydrolysis of phosphodiester bonds between the modified CMP residues and their 3'-neighbours with T2 and A RNAases. The method was verified with tRNATrp (yeast) and 5S RNA (rat liver and yeast).

Animals

Single-nucleotide transcription start sites profiling via Nascent Strand-Specific RNA sequencing uncovers IFN-γ-induced promoter dynamics.

Transcriptional regulation is a highly dynamic process in which nascent RNAs provide the most immediate readout of transcriptional activity. Precise mapping of transcription start sites (TSSs) is therefore critical for understanding promoter architecture and gene regulation, yet remains technically challenging. Here, we introduce Nascent Strand-Specific RNA sequencing (NSS-seq), a robust and streamlined method for genome-wide profiling of the capped 5' ends of nascent RNAs. By directly capturing transcription initiation events, NSS-seq overcomes the temporal delay inherent to conventional RNA-seq and enables time-resolved interrogation of transcriptional dynamics. Applied to interferon-γ (IFN-γ)-stimulation, NSS-seq uncovers previously unrecognized IFN-γ-responsive genes and transient transcription factor activation patterns underlying interferon-mediated tumor-suppressive functions. Together, NSS-seq provides a cost-effective and technically accessible platform for dissecting promoter-level regulatory dynamics during cellular responses.

Promoter Regions, Genetic

Unraveling Neuronal Identities Using SIMS: A Deep Learning Label Transfer Tool for Single-Cell RNA Sequencing Analysis.

Large single-cell RNA datasets have contributed to unprecedented biological insight. Often, these take the form of cell atlases and serve as a reference for automating cell labeling of newly sequenced samples. Yet, classification algorithms have lacked the capacity to accurately annotate cells, particularly in complex datasets. Here we present SIMS (Scalable, Interpretable Machine Learning for Single-Cell), an end-to-end data-efficient machine learning pipeline for discrete classification of single-cell data that can be applied to new datasets with minimal coding. We benchmarked SIMS against common single-cell label transfer tools and demonstrated that it performs as well or better than state of the art algorithms. We then use SIMS to classify cells in one of the most complex tissues: the brain. We show that SIMS classifies cells of the adult cerebral cortex and hippocampus at a remarkably high accuracy. This accuracy is maintained in trans-sample label transfers of the adult human cerebral cortex. We then apply SIMS to classify cells in the developing brain and demonstrate a high level of accuracy at predicting neuronal subtypes, even in periods of fate refinement, shedding light on genetic changes affecting specific cell types across development. Finally, we apply SIMS to single cell datasets of cortical organoids to predict cell identities and unveil genetic variations between cell lines. SIMS identifies cell-line differences and misannotated cell lineages in human cortical organoids derived from different pluripotent stem cell lines. When cell types are obscured by stress signals, label transfer from primary tissue improves the accuracy of cortical organoid annotations, serving as a reliable ground truth. Altogether, we show that SIMS is a versatile and robust tool for cell-type classification from single-cell datasets.

Brain organoids

Whole-transcriptome RNA sequencing and ceRNA network analyses provide novel insights into the antibacterial immune response of Hippocampus abdominalis against Vibrio harveyi.

Long non-coding RNAs (lncRNAs) stand as newly-arisen molecular types that exert regulatory effects, able to operate as competitive endogenous RNAs (ceRNAs) to engage microRNAs (miRNAs) in interaction, resulting in the recovery of target mRNA expression and activity. Increasing evidences indicate that the ceRNA network affects various biological processes in mammals, including development, cellular differentiation, metabolism, immune response, and disease pathogenesis. In teleost fish, the lncRNA-miRNA-mRNA regulatory networks have been reported occasionally. However, up to now, the roles of lncRNAs in the big-belly seahorse (Hippocampus abdominalis) remains unclear. In this study, we reported for the first time, via whole-transcriptome RNA sequencing, the lncRNA mediated ceRNA regulatory network in Vibrio harveyi-infected H. abdominalis. A total of 4197 differentially expressed mRNAs (DE-mRNAs), 1317 DE-lncRNAs, and 183 DE-miRNAs were identified. Furthermore, the crosstalk between miRNAs and lncRNAs as well as between miRNAs and mRNAs was inferred based on the negative correlations between miRNAs and their target lncRNAs/mRNAs. A core immune associated lncRNA-miRNA-mRNA putative regulatory network was thus constructed, comprising 211 lncRNA-miRNA and 224 mRNA-miRNA pairs. In conclusion, our findings provide an integrative overview of the ceRNA regulatory networks on the underlying immune responses to V. harveyi infection in the big-belly seahorse, and offer a solid theoretical foundation for the comparative immunological research of teleost fish.

Animals