Publications by authors named "Matthew E Ritchie"

Single-cell RNA sequencing (scRNA-seq) is a powerful technology that enables the measurement of gene expression in individual cells. Such precision provides insights into cellular heterogeneity that bulk methods might overlook. Fragile cells, in particular neutrophils, have posed significant challenges for scRNA-Seq due to their fragility, high RNase content and consequent loss during cryopreservation.

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  • Venetoclax is a novel drug that improves outcomes for chronic lymphocytic leukemia (CLL) patients, showing that early treatment response can predict long-term success.
  • Researchers used mass cytometry to analyze blood samples from CLL patients and found that venetoclax significantly reduced various CLL cell subpopulations while increasing survival proteins in the remaining cells.
  • The study suggests that CLL cells quickly adapt to therapies through survival signals like the B-cell activating factor (BAFF), indicating that combining treatments might lead to more effective and lasting results.
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  • * Nanopore direct RNA sequencing was found to be the best method for detecting RNA issues, including cryptic splicing and polyadenylation sites in lentiviral vectors.
  • * This sequencing technique can help optimize vector design, leading to better quality and more reliable lentiviral gene therapies.
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Apoptotic cell death is regulated by the BCL-2 protein family, with clusters of BAK or BAX homodimers driving pore formation in the mitochondrial outer membrane via a poorly understood process. There is growing evidence that, in addition to BAK and BAX, lipids play an important role in pore formation. Towards a better understanding of the lipidic drivers of apoptotic pore formation in isolated mitochondria, two complementary approaches were taken.

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Background: Abnormalities of in utero testis development are strongly associated with reproductive health conditions, including male infertility and testis cancer. In mouse testes, SOX9 and FGF9 support Sertoli cell development, while VEGF signalling is essential for the establishment of vasculature. The mitogen-activated protein kinase (MAPK) pathway is a major signalling cascade, essential for cell proliferation, differentiation and activation of Sry during primary sex-determination, but little is known about its function during fetal testis morphogenesis.

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X-linked genetic disorders typically affect females less severely than males owing to the presence of a second X Chromosome not carrying the deleterious variant. However, the phenotypic expression in females is highly variable, which may be explained by an allelic skew in X-Chromosome inactivation. Accurate measurement of X inactivation skew is crucial to understand and predict disease phenotype in carrier females, with prediction especially relevant for degenerative conditions.

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Germination involves highly dynamic transcriptional programs as the cells of seeds reactivate and express the functions necessary for establishment in the environment. Individual cell types have distinct roles within the embryo, so must therefore have cell type-specific gene expression and gene regulatory networks. We can better understand how the functions of different cell types are established and contribute to the embryo by determining how cell type-specific transcription begins and changes through germination.

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  • Recent advancements in sequencing-based spatial transcriptomics (sST) have improved how we measure gene expression across tissues, but there’s still a lack of comprehensive benchmarking for the various sST platforms.
  • This study established reference tissues to compare 11 sST methods, noting that molecular diffusion can affect resolution and variability across different platforms.
  • The findings suggest that sST data offer unique insights beyond traditional single-cell data, helping biologists choose the right platforms and setting the groundwork for standardized evaluation and future benchmarking in spatial transcriptomics.
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  • * They generated over 427 million long-read sequences and found that longer, more accurate sequences yield better transcript detection, while increased read depth enhances quantification.
  • * The study suggests that using reference-based tools works best for well-annotated genomes and recommends incorporating extra data to better identify rare transcripts, providing a benchmark for improving transcriptome analysis techniques in the future.
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Necroptosis is a lytic form of regulated cell death reported to contribute to inflammatory diseases of the gut, skin and lung, as well as ischemic-reperfusion injuries of the kidney, heart and brain. However, precise identification of the cells and tissues that undergo necroptotic cell death in vivo has proven challenging in the absence of robust protocols for immunohistochemical detection. Here, we provide automated immunohistochemistry protocols to detect core necroptosis regulators - Caspase-8, RIPK1, RIPK3 and MLKL - in formalin-fixed mouse and human tissues.

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Motivation: The process of analyzing high throughput sequencing data often requires the identification and extraction of specific target sequences. This could include tasks, such as identifying cellular barcodes and UMIs in single-cell data, and specific genetic variants for genotyping. However, existing tools, which perform these functions are often task-specific, such as only demultiplexing barcodes for a dedicated type of experiment, or are not tolerant to noise in the sequencing data.

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In transcriptomic analyses, it is helpful to keep track of the strand of the RNA molecules. However, the Oxford Nanopore long-read cDNA sequencing protocols generate reads that correspond to either the first or second-strand cDNA, therefore the strandedness of the initial transcript has to be inferred bioinformatically. Reverse transcription and PCR can also introduce artefacts which should be flagged in data pre-processing.

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The impact of the host immune environment on parasite transcription and fitness is currently unknown. It is widely held that hookworm infections have an immunomodulatory impact on the host, but whether the converse is true remains unclear. Immunity against adult-stage hookworms is largely mediated by Type 2 immune responses driven by the transcription factor Signal Transducer and Activator of Transcription 6 (STAT6).

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Differential expression analysis of RNA-seq is one of the most commonly performed bioinformatics analyses. Transcript-level quantifications are inherently more uncertain than gene-level read counts because of ambiguous assignment of sequence reads to transcripts. While sequence reads can usually be assigned unambiguously to a gene, reads are very often compatible with multiple transcripts for that gene, particularly for genes with many isoforms.

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Background: Disrupted germline differentiation or compromised testis development can lead to subfertility or infertility and are strongly associated with testis cancer in humans. In mice, SRY and SOX9 induce expression of Fgf9, which promotes Sertoli cell differentiation and testis development. FGF9 is also thought to promote male germline differentiation but the mechanism is unknown.

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scPipe is a flexible R/Bioconductor package originally developed to analyse platform-independent single-cell RNA-Seq data. To expand its preprocessing capability to accommodate new single-cell technologies, we further developed scPipe to handle single-cell ATAC-Seq and multi-modal (RNA-Seq and ATAC-Seq) data. After executing multiple data cleaning steps to remove duplicated reads, low abundance features and cells of poor quality, a object is created that contains a sparse count matrix with features of interest in the rows and cells in the columns.

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The lack of benchmark data sets with inbuilt ground-truth makes it challenging to compare the performance of existing long-read isoform detection and differential expression analysis workflows. Here, we present a benchmark experiment using two human lung adenocarcinoma cell lines that were each profiled in triplicate together with synthetic, spliced, spike-in RNAs (sequins). Samples were deeply sequenced on both Illumina short-read and Oxford Nanopore Technologies long-read platforms.

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  • Scientists are studying how a special protein called SMCHD1 works with DNA to control which genes are active or silent in cells.
  • A new mutation in this protein makes it better at silencing certain genes, which can mess up how certain genes are turned on or off in mice.
  • The research suggests that SMCHD1 has a tricky job; it affects gene silencing but doesn't always protect the DNA in the ways scientists thought before.
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  • The Long-read RNA-Seq Genome Annotation Assessment Project (LRGASP) Consortium aimed to evaluate long-read sequencing for analyzing transcripts by generating over 427 million sequences from various species.
  • The findings highlighted that longer, accurate sequences yield better transcript identification, while increased read depth enhances quantification accuracy, particularly in well-annotated genomes.
  • The study serves as a benchmark for transcriptome analysis strategies and suggests using additional data for detecting rare transcripts or employing reference-free methods.
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Group heteroscedasticity is commonly observed in pseudo-bulk single-cell RNA-seq datasets and its presence can hamper the detection of differentially expressed genes. Since most bulk RNA-seq methods assume equal group variances, we introduce two new approaches that account for heteroscedastic groups, namely voomByGroup and voomWithQualityWeights using a blocked design (voomQWB). Compared to current gold-standard methods that do not account for group heteroscedasticity, we show results from simulations and various experiments that demonstrate the superior performance of voomByGroup and voomQWB in terms of error control and power when group variances in pseudo-bulk single-cell RNA-seq data are unequal.

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Actinobacillus pleuropneumoniae is the cause of porcine pleuropneumonia, a severe respiratory tract infection that is responsible for major economic losses to the swine industry. Many host-adapted bacterial pathogens encode systems known as phasevarions (phase-variable regulons). Phasevarions result from variable expression of cytoplasmic DNA methyltransferases.

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When profiling blood samples by RNA-sequencing (RNA-seq), RNA from haemoglobin (Hgb) can account for up to 70% of the transcriptome. Due to considerations of sequencing depth and power to detect biological variation, Hgb RNA is typically depleted prior to sequencing by hybridisation-based methods; an alternative approach is to deplete reads arising from Hgb RNA bioinformatically. In the present study, we compared the impact of these two approaches on the outcome of differential gene expression analysis performed using RNA-seq data from 58 human tuberculosis (TB) patient or contact whole blood samples-29 globin kit-depleted and 29 matched non-depleted-a subset of which were taken at TB diagnosis and at six months post-TB treatment from the same patient.

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Venetoclax is an effective treatment for certain blood cancers, such as chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). However, most patients relapse while on venetoclax and further treatment options are limited. Combining venetoclax with immunotherapies is an attractive approach; however, a detailed understanding of how venetoclax treatment impacts normal immune cells in patients is lacking.

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Hexanucleotide expansion mutations in C9ORF72 are a frequent cause of amyotrophic lateral sclerosis. We previously reported that long arginine-rich dipeptide repeats (DPRs), mimicking abnormal proteins expressed from the hexanucleotide expansion, caused translation stalling when expressed in cell culture models. Whether this stalling provides a mechanism of pathogenicity remains to be determined.

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