Impact of disease-associated chromatin accessibility QTLs across immune cell types and contexts.

Only a third of immune-associated loci from genome-wide association studies (GWAS) colocalize with expression quantitative trait loci (eQTLs). To learn about causal genes and mechanisms at the remaining loci, we created a unified single-cell chromatin accessibility (scATAC-seq) map in peripheral blood comprising a total of 282,424 cells from 48 individuals. Clustering and topic modeling of scATAC data identified discrete cell-types and continuous cell states, which helped reveal disease-relevant cellular contexts, and allowed mapping of genetic effects on chromatin accessibility across these contexts.

Widespread gene-environment interactions shape the immune response to SARS-CoV-2 infection in hospitalized COVID-19 patients.

Genome-wide association studies performed in patients with coronavirus disease 2019 (COVID-19) have uncovered various loci significantly associated with susceptibility to SARS-CoV-2 infection and COVID-19 disease severity. However, the underlying -regulatory genetic factors that contribute to heterogeneity in the response to SARS-CoV-2 infection and their impact on clinical phenotypes remain enigmatic. Here, we used single-cell RNA-sequencing to quantify genetic contributions to -regulatory variation in 361,119 peripheral blood mononuclear cells across 63 COVID-19 patients during acute infection, 39 samples collected in the convalescent phase, and 106 healthy controls.

Systematic Modeling of Risk-Associated Copy Number Alterations in Cancer.

The determination of the cancer prognosis is paramount for patients and medical personnel so that they can devise treatment strategies. Transcriptional-based signatures and subtypes derived from cancer biopsy material have been used in clinical practice for several cancer types to aid in setting the patient prognosis and forming treatment strategies. Other genomic features in cancer biopsies, such as copy number alterations (CNAs), have been underused in clinical practice, and yet they represent a complementary source of molecular information that can add detail to the prognosis, which is supported by recent work in breast, ovarian, and lung cancers.

BCG vaccination alters the epigenetic landscape of progenitor cells in human bone marrow to influence innate immune responses.

Although the Bacille-Calmette-Guérin (BCG) vaccine is used to prevent tuberculosis, it also offers protection against a diverse range of non-mycobacterial infections. However, the underlying protective mechanisms in humans are not yet fully understood. Here, we surveyed at single-cell resolution the gene expression and chromatin landscape of human bone marrow, aspirated before and 90 days after BCG vaccination or placebo.

BCG vaccination impacts the epigenetic landscape of progenitor cells in human bone marrow.

While the Bacille-Calmette-Guérin (BCG) vaccine is used to prevent tuberculosis, it also offers protection against a diverse range of non-mycobacterial infections. However, the underlying protective mechanisms in humans are not yet fully understood. Here, we surveyed at single-cell resolution the gene expression and chromatin landscape of human bone marrow, aspirated before and 90 days after BCG vaccination or placebo administration.

Epithelial IFNγ signalling and compartmentalized antigen presentation orchestrate gut immunity.

All nucleated cells express major histocompatibility complex I and interferon-γ (IFNγ) receptor, but an epithelial cell-specific function of IFNγ signalling or antigen presentation by means of major histocompatibility complex I has not been explored. We show here that on sensing IFNγ, colonic epithelial cells productively present pathogen and self-derived antigens to cognate intra-epithelial T cells, which are critically located at the epithelial barrier. Antigen presentation by the epithelial cells confers extracellular ATPase expression in cognate intra-epithelial T cells, which limits the accumulation of extracellular adenosine triphosphate and consequent activation of the NLRP3 inflammasome in tissue macrophages.

Antigen-driven colonic inflammation is associated with development of dysplasia in primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is an immune-mediated disease of the bile ducts that co-occurs with inflammatory bowel disease (IBD) in almost 90% of cases. Colorectal cancer is a major complication of patients with PSC and IBD, and these patients are at a much greater risk compared to patients with IBD without concomitant PSC. Combining flow cytometry, bulk and single-cell transcriptomics, and T and B cell receptor repertoire analysis of right colon tissue from 65 patients with PSC, 108 patients with IBD and 48 healthy individuals we identified a unique adaptive inflammatory transcriptional signature associated with greater risk and shorter time to dysplasia in patients with PSC.

Transmission of stimulus-induced epigenetic changes through cell division is coupled to continuous transcription factor activity.

Trained immunity, or innate immune memory, has been attributed to the long-term retention of stimulus-induced histone post-translational modifications (PTMs) following clearance of the initial stimulus. Yet, it remains unknown how this epigenetic memory can persist for months in dividing cells given the lack of any known mechanism for stimulus-induced histone PTMs to be directly copied from parent to daughter strand during DNA replication. Here, using time course RNA-seq, ChIP-seq, and infection assays, we find that trained macrophages are transcriptionally, epigenetically, and functionally re-programmed for at least 14 cell divisions after stimulus washout.

GATA4 controls regionalization of tissue immunity and commensal-driven immunopathology.

There is growing recognition that regionalization of bacterial colonization and immunity along the intestinal tract has an important role in health and disease. Yet, the mechanisms underlying intestinal regionalization and its dysregulation in disease are not well understood. This study found that regional epithelial expression of the transcription factor GATA4 controls bacterial colonization and inflammatory tissue immunity in the proximal small intestine by regulating retinol metabolism and luminal IgA.

A systematic review and functional bioinformatics analysis of genes associated with Crohn's disease identify more than 120 related genes.

Background: Crohn's disease is one of the two categories of inflammatory bowel diseases that affect the gastrointestinal tract. The heritability estimate has been reported to be 0.75.

An integrative genomics approach identifies KDM4 as a modulator of trained immunity.

Innate immune cells are able to build memory characteristics via a process termed "trained immunity." Host factors that influence the magnitude of the individual trained immunity response remain largely unknown. Using an integrative genomics approach, our study aimed to prioritize and understand the role of specific genes in trained immunity responses.

Inflammatory Protein Profiles in Plasma of Candidaemia Patients and the Contribution of Host Genetics to Their Variability.

Circulatory inflammatory proteins play a significant role in anti- host immune defence. However, little is known about the genetic variation that contributes to the variability of inflammatory responses in response to . To systematically characterize inflammatory responses in infection, we profiled 91 circulatory inflammatory proteins in peripheral blood mononuclear cells (PBMCs) stimulated with yeast isolated from 378 individuals of European origin from the 500 Functional Genomics (500FG) cohort of the Human Functional Genomics Project (HFGP) and Lifelines Deep cohort.

Seasonal and Nonseasonal Longitudinal Variation of Immune Function.

Different components of the immune response show large variability between individuals, but they also vary within the same individual because of host and environmental factors. In this study, we report an extensive analysis of the immune characteristics of 56 individuals over four timepoints in 1 single year as part of the Human Functional Genomics Project. We characterized 102 cell subsets using flow cytometry; quantified production of eight cytokines and two chemokines in response to 20 metabolic, bacterial, fungal, and viral stimuli; and measured circulating markers of inflammation.

Integration of metabolomics, genomics, and immune phenotypes reveals the causal roles of metabolites in disease.

Background: Recent studies highlight the role of metabolites in immune diseases, but it remains unknown how much of this effect is driven by genetic and non-genetic host factors.

Result: We systematically investigate circulating metabolites in a cohort of 500 healthy subjects (500FG) in whom immune function and activity are deeply measured and whose genetics are profiled. Our data reveal that several major metabolic pathways, including the alanine/glutamate pathway and the arachidonic acid pathway, have a strong impact on cytokine production in response to ex vivo stimulation.

Systematic Prioritization of Candidate Genes in Disease Loci Identifies as a Master Regulator of IFNγ Signaling in Celiac Disease.

Celiac disease (CeD) is a complex T cell-mediated enteropathy induced by gluten. Although genome-wide association studies have identified numerous genomic regions associated with CeD, it is difficult to accurately pinpoint which genes in these loci are most likely to cause CeD. We used four different approaches-Mendelian randomization inverse variance weighting, COLOC, LD overlap, and DEPICT-to integrate information gathered from a large transcriptomics dataset.

Genome-Wide Association Study Identifies Novel Colony Stimulating Factor 1 Locus Conferring Susceptibility to Cryptococcosis in Human Immunodeficiency Virus-Infected South Africans.

Background: is the most common cause of meningitis in human immunodeficiency virus (HIV)-infected Africans. Despite universal exposure, only 5%-10% of patients with HIV/acquired immune deficiency syndrome and profound CD4 T-cell depletion develop disseminated cryptococcosis: host genetic factors may play a role. Prior targeted immunogenetic studies in cryptococcosis have comprised few Africans.

Deconvolution of bulk blood eQTL effects into immune cell subpopulations.

Background: Expression quantitative trait loci (eQTL) studies are used to interpret the function of disease-associated genetic risk factors. To date, most eQTL analyses have been conducted in bulk tissues, such as whole blood and tissue biopsies, which are likely to mask the cell type-context of the eQTL regulatory effects. Although this context can be investigated by generating transcriptional profiles from purified cell subpopulations, current methods to do this are labor-intensive and expensive.

Sex-Specific Regulation of Inflammation and Metabolic Syndrome in Obesity.

Objective: Metabolic dysregulation and inflammation are important consequences of obesity and impact susceptibility to cardiovascular disease. Anti-inflammatory therapy in cardiovascular disease is being developed under the assumption that inflammatory pathways are identical in women and men, but it is not known if this is indeed the case. In this study, we assessed the sex-specific relation between inflammation and metabolic dysregulation in obesity.

Tissue alarmins and adaptive cytokine induce dynamic and distinct transcriptional responses in tissue-resident intraepithelial cytotoxic T lymphocytes.

The respective effects of tissue alarmins interleukin (IL)-15 and interferon beta (IFNβ), and IL-21 produced by T cells on the reprogramming of cytotoxic T lymphocytes (CTLs) that cause tissue destruction in celiac disease is poorly understood. Transcriptomic and epigenetic profiling of primary intestinal CTLs showed massive and distinct temporal transcriptional changes in response to tissue alarmins, while the impact of IL-21 was limited. Only anti-viral pathways were induced in response to all the three stimuli, albeit with differences in dynamics and strength.

Arresting proliferation improves the cell identity of corneal endothelial cells in the New Zealand rabbit.

Purpose: Corneal endothelium engineering aims to reduce the tissue shortage for corneal grafts. We investigated the impact of mitogenic and resting culture systems on the identity of corneal endothelial cells (CECs) for tissue engineering purposes.

Methods: Rabbit CECs were cultured in growth factor-supplemented media (MitoM) until confluence.

ER stress and UPR activation in glioblastoma: identification of a noncanonical PERK mechanism regulating GBM stem cells through SOX2 modulation.

Patients with aggressive brain tumors, named glioblastoma multiforme (GBM), have a poor prognoses. Here we explored if the ER stress/unfolded protein response (UPR) is involved in the pathophysiology of GBM and may provide novel therapeutic targets. Immunohistochemical analyses of a tissue microarray containing primary GBM specimens showed strong variability in expression of the UPR markers GRP78/BiP, XBP1, and ATF4.

A Genome-Wide Functional Genomics Approach Identifies Susceptibility Pathways to Fungal Bloodstream Infection in Humans.

Background: Candidemia, one of the most common causes of fungal bloodstream infection, leads to mortality rates up to 40% in affected patients. Understanding genetic mechanisms for differential susceptibility to candidemia may aid in designing host-directed therapies.

Methods: We performed the first genome-wide association study on candidemia, and we integrated these data with variants that affect cytokines in different cellular systems stimulated with Candida albicans.

The Inter-Relationship of Platelets with Interleukin-1β-Mediated Inflammation in Humans.

Background:  Inflammation and coagulation are key processes in cardiovascular diseases (CVDs). The Canakinumab Anti-inflammatory Thrombosis Outcome Study trial affirmed the importance of inflammation in CVD by showing that inhibition of the interleukin (IL)-1β pathway prevents recurrent CVD. A bi-directional relationship exists between inflammation and coagulation, but the precise interaction of platelets and IL-1β-mediated inflammation is incompletely understood.

Integration of multi-omics data and deep phenotyping enables prediction of cytokine responses.

The immune response to pathogens varies substantially among people. Whereas both genetic and nongenetic factors contribute to interperson variation, their relative contributions and potential predictive power have remained largely unknown. By systematically correlating host factors in 534 healthy volunteers, including baseline immunological parameters and molecular profiles (genome, metabolome and gut microbiome), with cytokine production after stimulation with 20 pathogens, we identified distinct patterns of co-regulation.

DNA methylation in childhood asthma: an epigenome-wide meta-analysis.

Background: DNA methylation profiles associated with childhood asthma might provide novel insights into disease pathogenesis. We did an epigenome-wide association study to assess methylation profiles associated with childhood asthma.

Methods: We did a large-scale epigenome-wide association study (EWAS) within the Mechanisms of the Development of ALLergy (MeDALL) project.