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30 records · Page 2Linked to original sources

Novel Predictive Spatial Biomarker in Non-Small Cell Lung Carcinoma: The Diversity of Niches Unlocking Treatment Sensitivity (DONUTS).

Probabilistic spatial modelling techniques developed on large-scale tumor-immune Atlases (~35M individually mapped cells; 50,000 high power fields) were used to characterize predictive features of treatment-responsive lung cancer. We identified CD8+FoxP3+ cell density as a robust pre-treatment biomarker for outcomes across disease stages and therapy types. In parallel, single-cell RNAseq studies of CD8+FoxP3+ T-cells revealed an activated, early effector phenotype, substantiating an anti-tumor role, and contrasting with CD4+FoxP3+ T-regulatory cells. A spatial biomarker was developed using an empirical probabilistic model to define the immediate cell neighbors or niche surrounding CD8+FoxP3+ cells and proximity to the tumor-stromal boundary. The resultant 'Diversity of Niches Unlocking Treatment Sensitivity (DONUTS)' are more prevalent than the CD8+FoxP3+ cells themselves, mitigating sampling error in small biopsies. Further, the DONUTS only require four markers, are additive to PD-L1, and associate with tertiary lymphoid structure counts. Taken together, the DONUTS represent a next-generation predictive biomarker poised for clinical implementation.

AstroPath

A method for authenticating the fidelity of Cryptococcus neoformans knockout collections.

Gene knockout (KO) strain collections are important tools for discovery in microbiology. Cryptococcus neoformans, a human fungal pathogen, has an available genome-wide gene deletion collection that is widely used by the research community. We uncovered mix-ups in the assembly of the commercially available C. neoformans deletion collection of ~4,700 unique strains acquired by our laboratory. Evidence supporting a mix-up includes RNAseq analysis that identified transcripts for the gene listed as the KO. The mystery was soon solved as this same KO strain lacked RNA transcripts for a different KO strain gene found in the same plate position in an earlier partial KO collection, suggesting a plate swap between two KO collections. Therefore, we developed a quick PCR assay to distinguish the two KO collections based on the size differences between their nourseothricin (NAT)-resistance cassettes, confirmed by genome sequencing. Here, we report that nine of the first 15 plates of the 42-plate our KN99ɑ KO collection had been replaced with the corresponding plates from an earlier partial KO collection. We provide additional evidence that the remaining plates are correct, and the simple authentication method presented here serves as a quick check to identify similar mix-ups in the KO collections.IMPORTANCEGene KO strain collections are important tools for discovery in microbiology. The human fungal pathogen Cryptococcus neoformans has an available genome-wide deletion collection that is widely used by the research community. Here, we report that our KN99ɑ collection is comprised of mixed plates from two independent KO libraries and present a simple authentication method that other investigators can use to distinguish the identities of these KO collections. Above all, this article serves as a reminder to users of the 2015 KO library collection to screen the plates before undertaking large phenotyping experiments.

Cryptococcus neoformans

Sex and tissue resolved co-expression networks reveal a female placental-brain axis protective against prenatal PCB exposure.

BACKGROUND: Neurodevelopmental disorders have a strong male bias that is poorly understood. The placenta provides molecular information about environmental interactions with genetics (including biological sex) that shape developmental processes in the brain. We investigate placental-brain transcriptional responses in an established mouse model of prenatal exposure to a human-relevant mixture of polychlorinated biphenyls (PCBs). RESULTS: To understand sex, tissue, and dosage effects in embryonic (E18) brain and placenta RNAseq data, we use weighted gene correlation network analysis (WGCNA) to create gene networks that could be compared across sex or tissue. WGCNA reveals that expression within most correlated gene networks is significantly and strongly associated with PCB exposure, but frequently in opposite directions between male-female and placenta-brain comparisons. In WGCNA and differentially expressed gene analyses, more transcriptional changes are observed in male brain than placenta, but the reverse is seen in females. Furthermore, female X-inactive specific transcript (Xist) levels correlate with sex-specific and non-monotonic PCB dose response, suggesting an X-linked protective epigenetic mechanism. The transcriptomic effects of low-dose PCB exposure are significantly opposed by dietary folic acid supplementation across both sexes but are strongest in female placentas. PCB and folic acid interacting gene networks are enriched in metabolic pathways involved in energy usage and translation, with female-specific protective effects enriched in PPAR, thermogenesis, glycerolipid, and O-glycan biosynthesis, as opposed to toxicant responses in male brain. CONCLUSIONS: A female protective effect in response to prenatal PCB exposure appears to be mediated by dose-dependent sex differences in transcriptional modulation of placental metabolic pathways.

Female

LymphGen-Sig: Integrating Genetic and Transcriptional States to Predict Therapeutic Response in Diffuse Large B-Cell Lymphoma.

PURPOSE: Genetic classification may advance precision medicine in diffuse large B-cell lymphoma (DLBCL), but existing tools like LymphGen (LG) are limited by complexity and incomplete classification and do not incorporate nongenetic features that affect disease biology and therapeutic outcomes. To address these limitations, we developed LG-sig (LGsig), a gene expression-based platform that classifies all DLBCLs and harmonizes both genetic and nongenetic dimensions of the disease. METHODS: LGsig was built on the distinct subtype-specific gene expression signature of each LG class using paired genomic and transcriptomic data (National Cancer Institute/British Columbia Cancer Agency; N = 764). Model development was restricted to DLBCLs classified into MYD88L265P and CD79B mutations (MCD), BCL6 translocation and NOTCH2 mutations (BN2), EZH2 mutations and BCL2 translocation (EZB), or SGK1 and TET2 mutations (ST2). Gene features were selected by differential gene expression, with 294 genes being optimal for classification using a nearest shrunken centroid classifier. LGsig classifications were designated as MCDsig, BN2sig, ST2sig, and EZBsig. The final model was applied to RNAseq from archival samples from the POLARIX trial (N = 678) to assess outcomes after polatuzumab vedotin-R-CHP (pola-R-CHP) or rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) for each LGsig subtype. RESULTS: LGsig accurately identified LG subtypes using transcriptional data alone and extended assignments to all previously LG-unclassified cases. Importantly, LG-unclassified DLBCLs reassigned by LGsig mirrored the transcriptional and clinical features of their corresponding LG counterparts, supporting their reclassification. In addition, LGsig reassigned LG A53 DLBCLs, characterized by aneuploidy and TP53 alterations, into more biologically and therapeutically relevant LGsig clusters. Finally, LGsig improved the performance of LG as a biomarker in the POLARIX study, by identifying distinct DLBCL subtypes exhibiting a survival benefit with pola-R-CHP over R-CHOP in both LG-classified and LG-unclassified cases. CONCLUSION: LGsig expands molecular classification beyond current genetic classifiers in DLBCL by integrating both genetic and transcriptional dimensions of the disease to better inform subtype-specific therapeutic strategies.

Journal Article

Hepatocyte dedifferentiation in 2D culture reveals extensive transcriptomic and proteomic rewiring.

BACKGROUND: Primary hepatocytes are commonly used in vitro to model liver metabolism, but prolonged culturing results in dedifferentiation and potentially limits the applicability of this model. METHODS: We characterized the transcriptome and proteome of full liver and primary hepatocytes as either freshly isolated cells or after 24 hours of 2D-culturing. RESULTS: We found that 2D-culturing for 24 hours changes more than 10,000 genes and 3000 proteins compared with freshly isolated cells, accompanied by a decrease in transcriptional heterogeneity and a loss of zonal markers. Moreover, there were changes in proteins associated with the extracellular matrix, in mitochondrial and ribosomal protein abundances, as well as an increase in the abundance of acute-phase response proteins. CONCLUSION: Collectively, primary mouse hepatocytes in culture rewire the transcriptome and proteome, which may affect the utility of this model to study physiological and molecular mechanisms related to the liver. We developed the Shiny app "Hepamorphosis" (https://cbmr.ku.dk/research/resources/shiny-apps/), which allows users to explore RNA/protein correlations, zonation profiles, and cell-type-specific transcription in full liver and cultured hepatocytes.

Hepatocytes

HERV Modulation in Colorectal Carcinoma Patients: A Snapshot of Endogenous Retroviral Transcriptome.

Human endogenous retroviruses (HERVs) are proviral relics of infections that affected primates' germ line. Many HERV elements retain a residual capacity to encode transcripts and proteins that have been occasionally domesticated for the host physiology. In addition, HERV transcriptional modulation is of great interest to clarify the etiology of complex disorders such as cancer, even if a few studies assessed the specific HERV loci modulated in tumor tissues. In the present work, we used a transcriptomic approach to investigate the specific expression of ~3300 HERV loci in paired tumor and normal tissues of 7 colorectal cancer (CRC) patients. A total of 102 HERVs were significantly modulated in CRC, with a general tendency towards downregulation. Of note, among the 42 upregulated HERVs 23 belonged to the HERV-H group, that is the most investigated in CRC. De novo transcriptome reconstruction and qPCR validation allowed to identify a transcript from a HERV-H locus on chromosome Xp22.3 with high specific expression in CRC samples, potentially encoding for a partial Pol protein. These results provide a detailed description of HERV transcriptional variations in CRC and its interindividual variability, identifying a HERV-H transcript that deserves further investigation for its possible impact on tumor progression.

Endogenous Retroviruses

Chemical Complementarities of Neuroblastoma Tumor-Resident TCR CDR3s and CMV Antigens are Associated with a Better Outcome.

A likely immune response to a virus can be detected via the presence of TCR CDR3s that (a) exactly match CDR3s known to bind viral antigens or (b) represent chemical complementarity to viral antigens. Previous studies, based on genomics approaches to characterizing anti-CMV TCR CDR3s in patient blood samples, have indicated the possibility that a systemic CMV infection is associated with worse outcomes for NBL, as well as for breast cancer. Thus, the association of NBL tumor-resident anti-CMV TCR CDR3s and patient outcomes was evaluated here, with results indicating that high levels of chemical complementarity between tumor-resident TCR CDR3s and CMV antigens represented a better outcome. This is in apparent contrast to results obtained via the previous study of blood sourced, anti-CMV TCR CDR3s representing a worse outcome. This study identified gene expression values associated with the tumor-specific anti-CMV TCR CDR3s, representing exact matches to known anti-CMV TCR CDR3s, which may assist in identifying a potential underlying mechanism effecting the better outcomes associated with the tumor-resident, anti-CMV TCR CDR3s. Overall, results here raise the question of whether an anti-CMV response directly against the tumor, or within the tumor microenvironment, is involved in reductions in tumor progression or responsiveness to treatment?

Humans

Detection of mitochondrial tDRs in killifish embryos and other non-model organisms.

In recent years a diversity of small noncoding RNAs have been identified that originate from the mitochondrial genome. These mitosRNAs are often dominated by tRNA-derived small RNAs (mito-tDRs). Differential expression of mito-tDRs is associated with responses to stress. They also appear to be expressed differentially during development and their expression may be enriched in stress-tolerant animals. Very little is currently known about roles or modes of action of these sequences, although they are implicated in a diversity of processes such as cell cycle regulation, mRNA stability, regulation of ROS production, and import of proteins into the mitochondrion. To better understand the various roles these sequences may play, it is critical that we understand their diversity, cellular location, and the context for their expression. This protocol outlines the methodologies used to detect mitosRNAs, including mito-tDRs, in embryos and cells of the annual killifish Austrofundulus limnaeus. We highlight critical steps in the isolation of RNA, creation of sequencing libraries, bioinformatics processing of sequence data, and methods for validation of expression that support a robust discovery pipeline for mitosRNAs even from species with incomplete reference genome sequences.

Animals

Differential gene expression study in whole blood identifies candidate genes for psychosis in African American individuals.

Genome-wide association has identified regions of the genome that mediate risk for psychosis. It is possible that variants in these regions confer risk by altering gene expression. This work has predominantly been conducted in individuals of European descent and has focused narrowly on schizophrenia rather than psychosis as a syndrome. In the present study we investigated alterations in gene expression in African American individuals with a range of psychotic diagnoses to increase understanding of the etiology in an underserved population. We performed RNA-seq in whole bloody to survey the transcriptome in 126 patients with a psychosis-spectrum disorder and 217 healthy controls and applied differential gene expression analyses across the genome while controlling for age, sex, population stratification and batch. We found 18 differentially expressed genes (DEGs), some of the locations of the corresponding genes overlap with previously implicated regions for psychosis, but many of which were novel associations. Enrichment analysis of nominally significant genes (p&#xa0;<&#xa0;0.05) revealed overrepresentation of biological processes relating to platelet, immune and cellular function, and sensory perception. Weighted gene co-expression network analysis, applied to identify modules of co-expressed genes associated with psychosis, revealed 10 modules, one of which was significantly associated with psychosis. This module was significantly enriched for DEGs, and for platelet function. These results support the potential role of immune function in the etiology of psychosis, identify novel candidate gene expression phenotypes that correspond to both established and new genomic regions, in individuals of African American ancestry.

Humans

Protocol to identify genes required for cardiomyocyte development using Perturb-Seq.

While Perturb-Seq combines CRISPR-based screening with single-cell RNA sequencing (scRNA-seq), large-scale experiments are costly and its application during development is complicated by differentiation heterogeneity. Here, we present a protocol to identify genes required for cardiomyocyte development using Perturb-Seq. We describe steps for sgRNA (single guide RNA) library cloning and infection, cardiomyocyte differentiation, cell hashing, super loading, and scRNA-seq. We then detail procedures for sequencing, mapping, and data analysis. For complete details on the use and execution of this protocol, please refer to Sivakumar et al.1.

CRISPR

Evolution after whole-genome duplication (WGD) drives phenotypic and transcriptomic divergence more than WGD in an autopolyploid herb.

Whole-genome duplication (WGD) is a major driver of plant speciation and often hypothesized to promote rapid adaptation to new or changing environmental conditions. However, the extent to which WGD per se fosters phenotypic and transcriptional novelties, and the relative contribution of WGD-induced changes vs post-WGD evolution to trait differentiation between cytotypes remains poorly understood. Here, we investigated the phenotypic and transcriptomic consequences of WGD and subsequent evolution in the Biscutella laevigata diploid-autotetraploid complex by comparing replicated diploid, synthetic autotetraploids, and natural autotetraploids (originated some 24,000 to 7,000 generations ago) under moderate daily temperature fluctuations (stable) vs. daily heat stress (changing) conditions. WGD led to reduced specific leaf area and slower rosette growth but had no significant effect on biomass. Post-WGD evolution acted in contrasting directions on WGD-induced changes, either reverting traits to diploid-like values or maintaining them in natural autotetraploids. Overall, WGD induced a decrease in fitness that was mitigated by post-WGD evolution, resulting in natural autotetraploids with similar or higher fitness under changing conditions than diploids. While the genetic background modulates the effects of WGD, cytotype-level transcriptomic analyses revealed limited immediate effects of WGD under stable conditions, although heat stress induced different responses across cytotypes. Altogether, our results highlight a complex interplay between immediate WGD-induced and subsequent evolution at the phenotypic and transcriptomic levels, supporting a predominant role of post-WGD evolution in the differentiation of current cytotypes and the adaptive evolution of autotetraploids of B. laevigata.

Genome, Plant

Diet change reveals asymmetric response in gene expression and microbial composition across the digestive tract of two closely related herbivores.

BACKGROUND: Understanding what shapes variation in organisms' capacity to utilize novel resources is essential to predicting how species will respond to environmental change. For herbivores, exposure to toxic phytochemicals in novel plants may limit persistence in new habitats. We investigated the behavioral, physiological, genetic, and microbial consequences of diet switching in two closely related species of rodent herbivores that each consume differentially toxic plants in their native habitat, and that maintain different dietary strategies (i.e., relative dietary specialist versus relative generalist). RESULTS: In reciprocal laboratory feeding trials, we exposed wild-caught woodrats (genus Neotoma) to toxins characteristic of either familiar or novel plant secondary compounds. We measured changes in food and water intake, locomotor activity, gut microbial composition, and gene expression across the digestive tract following feeding trials. The dietary generalist responded minimally, but the specialist responded strongly when exposed to the novel diet. This response included behavioral and genetic components including increased water intake, reduction in locomotor activity, increased differential expression of detoxification genes, and a greater shift in gut microbial composition. CONCLUSIONS: The dietary specialist exhibited a strong response to diet switching that corresponded with ecologically relevant shifts in behavior and physiology that would have negative fitness consequences. Although the dietary specialist had a strong genetic and microbial response to novel plant secondary compounds, this response would likely be insufficient to overcome the immediate challenge of exposure to novel dietary toxins in the wild. Our results underscore the link between feeding strategy and the capacity to shift to novel dietary resources in response to environmental change.

Animals