Publications by authors named "Mathieu Bourgey"

Brain regions drive multiple physiological functions through specific gene expression patterns that adapt to environmental influences, drug treatments and disease conditions. To generate a detailed atlas of the brain transcriptome in the context of diabetes, we carried out RNA sequencing in hypothalamus, hippocampus, brainstem and striatum of the Goto-Kakizaki (GK) rat model of spontaneous type 2 diabetes, which was applied to identify gene transcription adaptation to improved glycemic control following vertical sleeve gastrectomy (VSG) in the GK. Over 19,000 distinct transcripts were detected in the rat brain, including 2794 which were consistently expressed in the four brain regions.

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The basal breast cancer subtype is enriched for triple-negative breast cancer (TNBC) and displays consistent large chromosomal deletions. Here, we characterize evolution and maintenance of chromosome 4p (chr4p) loss in basal breast cancer. Analysis of The Cancer Genome Atlas data shows recurrent deletion of chr4p in basal breast cancer.

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Whole genome sequencing (WGS) at high-depth (30X) allows the accurate discovery of variants in the coding and non-coding DNA regions and helps elucidate the genetic underpinnings of human health and diseases. Yet, due to the prohibitive cost of high-depth WGS, most large-scale genetic association studies use genotyping arrays or high-depth whole exome sequencing (WES). Here we propose a cost-effective method which we call "Whole Exome Genome Sequencing" (WEGS), that combines low-depth WGS and high-depth WES with up to 8 samples pooled and sequenced simultaneously (multiplexed).

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Perivascular space (PVS) burden is an emerging, poorly understood, magnetic resonance imaging marker of cerebral small vessel disease, a leading cause of stroke and dementia. Genome-wide association studies in up to 40,095 participants (18 population-based cohorts, 66.3 ± 8.

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  • Inborn errors affecting the immune response to IFN-γ lead to mycobacterial diseases, while errors in IFN-α/β impact defense against viral infections.
  • A study of children with complete IRF1 deficiency showed they suffered from severe mycobacterial infections but displayed normal responses to various viruses, including SARS-CoV-2.
  • IRF1 plays a crucial role in the immune response to mycobacteria, enhancing IFN-γ responses, while its absence does not significantly hinder antiviral defenses associated with IFN-α/β.
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  • Patients with inherited CARMIL2 or CD28 deficiencies show defective T cell signaling, but CARMIL2's role is less understood.
  • Research indicates that the mutant CARMIL2 alleles affect T cell activation and lead to specific immunological issues including low counts of memory T cells and NK cells, as well as weak antibody responses.
  • CARMIL2 deficiency leads to serious health issues by age 10, including frequent infections and inflammation, and milder symptoms are observed in patients with somatic reversions in T cells.
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  • * This study analyzed rare genetic variants by combining data from 21 cohorts worldwide, involving over 5,000 severe cases and 571,000 controls.
  • * A significant finding showed that a rare harmful variant in the TLR7 gene greatly increases the risk of severe COVID-19, indicating that rare variants could offer valuable insights for understanding and treating the disease.
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Cerebral white matter hyperintensities on MRI are markers of cerebral small vessel disease, a major risk factor for dementia and stroke. Despite the successful identification of multiple genetic variants associated with this highly heritable condition, its genetic architecture remains incompletely understood. More specifically, the role of DNA methylation has received little attention.

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The precisionFDA Truth Challenge V2 aimed to assess the state of the art of variant calling in challenging genomic regions. Starting with FASTQs, 20 challenge participants applied their variant-calling pipelines and submitted 64 variant call sets for one or more sequencing technologies (Illumina, PacBio HiFi, and Oxford Nanopore Technologies). Submissions were evaluated following best practices for benchmarking small variants with updated Genome in a Bottle benchmark sets and genome stratifications.

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  • Even with good vaccines, there aren't great medicine options for treating severe COVID-19, which makes it dangerous.
  • In a study, researchers looked at patients in the hospital and found differences in their immune cells that showed who might survive and who might not.
  • They discovered specific body processes that were overactive in those who didn't survive and suggested three drugs that could help treat serious COVID-19 cases.
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Background: Québec was the Canadian province most impacted by COVID-19, with 401,462 cases as of September 24th, 2021, and 11,347 deaths due mostly to a very severe first pandemic wave. In April 2020, we assembled the Coronavirus Sequencing in Québec (CoVSeQ) consortium to sequence SARS-CoV-2 genomes in Québec to track viral introduction events and transmission within the province.

Methods: Using genomic epidemiology, we investigated the arrival of SARS-CoV-2 to Québec.

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We studied a child with severe viral, bacterial, fungal, and parasitic diseases, who was homozygous for a loss-of-function mutation of REL, encoding c-Rel, which is selectively expressed in lymphoid and myeloid cells. The patient had low frequencies of NK, effector memory cells reexpressing CD45RA (Temra) CD8+ T cells, memory CD4+ T cells, including Th1 and Th1*, Tregs, and memory B cells, whereas the counts and proportions of other leukocyte subsets were normal. Functional deficits of myeloid cells included the abolition of IL-12 and IL-23 production by conventional DC1s (cDC1s) and monocytes, but not cDC2s.

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  • The study looks at a patient and their relatives who have unusual skin growths caused by human papilloma virus (HPV).
  • The patients have a specific genetic change that makes a part of their immune cells (T cells) not work properly, which affects how their body fights off HPV.
  • Even though their T cells don’t respond well to HPV, the patients can still make antibodies against the viruses, showing that they can fight infections differently than expected.
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The pathophysiology of adverse events following programmed cell death protein 1 (PD-1) blockade, including tuberculosis (TB) and autoimmunity, remains poorly characterized. We studied a patient with inherited PD-1 deficiency and TB who died of pulmonary autoimmunity. The patient's leukocytes did not express PD-1 or respond to PD-1-mediated suppression.

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A recent report found that rare predicted loss-of-function (pLOF) variants across 13 candidate genes in TLR3- and IRF7-dependent type I IFN pathways explain up to 3.5% of severe COVID-19 cases. We performed whole-exome or whole-genome sequencing of 1,864 COVID-19 cases (713 with severe and 1,151 with mild disease) and 15,033 ancestry-matched population controls across 4 independent COVID-19 biobanks.

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  • * The ureteric bud helps form the kidney's collecting ducts and encourages the creation of nephrons, which are important for filtering waste.
  • * Researchers found out how certain cells change and organize to form the ureteric bud, which may help in understanding kidney issues and developing effective treatments.
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  • A new blood test was developed to measure damage caused by COVID-19 to various organs using methylation profiling of cell-free DNA in plasma.
  • The study involved analyzing plasma samples from COVID-19 patients, revealing significant organ injury, particularly to the lungs and liver, which correlates with disease severity.
  • Findings suggest cell-free DNA could be a valuable tool for monitoring and understanding the impact of COVID-19 across multiple organ systems.
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A recent report found that rare predicted loss-of-function (pLOF) variants across 13 candidate genes in TLR3- and IRF7-dependent type I IFN pathways explain up to 3.5% of severe COVID-19 cases. We performed whole-exome or whole-genome sequencing of 1,934 COVID-19 cases (713 with severe and 1,221 with mild disease) and 15,251 ancestry-matched population controls across four independent COVID-19 biobanks.

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Population sequencing often requires collaboration across a distributed network of sequencing centers for the timely processing of thousands of samples. In such massive efforts, it is important that participating scientists can be confident that the accuracy of the sequence data produced is not affected by which center generates the data. A study was conducted across three established sequencing centers, located in Montreal, Toronto, and Vancouver, constituting Canada's Genomics Enterprise (www.

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  • The text discusses a patient with a rare genetic condition that leads to a deficiency in the transcription factor T-bet, resulting in a heightened susceptibility to mycobacterial diseases.
  • The patient exhibits very low levels of various immune cells that are crucial for fighting off mycobacterial infections, including natural killer (NK) cells and other specialized T cells, which also produce insufficient amounts of interferon gamma (IFN-γ).
  • Despite some immune cells functioning normally, the overall immune response is compromised, as the lack of essential immune components cannot be compensated by the remaining T cells that react to mycobacterial antigens.
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COVID-19 primarily affects the lungs, but evidence of systemic disease with multi-organ involvement is emerging. Here, we developed a blood test to broadly quantify cell, tissue, and organ specific injury due to COVID-19, using genome-wide methylation profiling of circulating cell-free DNA in plasma. We assessed the utility of this test to identify subjects with severe disease in two independent, longitudinal cohorts of hospitalized patients.

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Cancer stem cells are critical for cancer initiation, development, and treatment resistance. Our understanding of these processes, and how they relate to glioblastoma heterogeneity, is limited. To overcome these limitations, we performed single-cell RNA sequencing on 53586 adult glioblastoma cells and 22637 normal human fetal brain cells, and compared the lineage hierarchy of the developing human brain to the transcriptome of cancer cells.

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While comparison of primary tumor and metastases has highlighted genomic heterogeneity in colorectal cancer (CRC), previous studies have focused on a single metastatic site or limited genomic testing. Combining data from whole exome and ultra-deep targeted sequencing, we explored possible evolutionary trajectories beyond the status of these mutations, particularly among patient-matched metastatic tumors. Our findings confirm the persistence of known clinically-relevant mutations (e.

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Recent reports have identified differences in the mutational spectra across human populations. Although some of these reports have been replicated in other cohorts, most have been reported only in the 1000 Genomes Project (1kGP) data. While investigating an intriguing putative population stratification within the Japanese population, we identified a previously unreported batch effect leading to spurious mutation calls in the 1kGP data and to the apparent population stratification.

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