A new subgroup of hepatocellular adenomas with sonic hedgehog pathway activation
Hepatocellular adenomas (HCA) are benign liver tumors divided in molecular subtypes characterized by mutations inactivating HNF1A, activating β-catenin or the IL-6/JAK/STAT inflammatory pathway. Molecular analyses of 533 HCA developed in 411 patients identified a new tumor subgroup with Sonic Hedgehog pathway activation due to focal deletions creating INHBE promoter/GLI1 fusions.
Study
EGAS00001002091
Exploring the role of mtDNA variation in Multiple Sclerosis in a large cohort of discordant monozygotic twins
Several lines of evidence indicate that mitochondrial DNA (mtDNA) variants might predispose to multiple sclerosis (MS). We examined this in 49 monozygotic (MZ) twin pairs clinically discordant for MS at study entry. Since the nuclear DNA of MZ twins is identical, our study provides a unique setting to functionally associate unique mtDNA variants and skewed heteroplasmy with MS development. In order to identify mtDNA variants in the twin cohort, we deeply sequenced the mitochondrial genome in blood of all 49 MZ twin pairs using next generation sequencing (Illumina, HiSeq or MiSeq) with an average coverage depth of ~25,000 sequences per base. Heteroplasmic variants were validated using targeted deep sequencing (TDS) (Illumina, MiSeq) in DNA isolated from blood and buccal swabs. In addition, whole blood was also available of 5 additional MS-affected or healthy siblings and 1 dizygotic twin pair discordant for MS, comprising in total 6 non-identical sib pairs. Moreover, all cases were screened for pathogenic mtDNA polymerase gamma (POLG) mutations. The data provides valuable insights in the possible involvement of mtDNA variants in the pathogenesis of MS, and gives information on the segregation of heteroplasmic variants within MZ twins and non-identical siblings and across different tissues.
Study
EGAS00001001240
Stereotyped B-cell responses are linked to IgG constant region polymorphisms in multiple sclerosis
Clonally related B cells infiltrate the brain, meninges, and cerebrospinal fluid of multiple sclerosis (MS) patients, but the mechanisms driving the B-cell response and shaping the immunoglobulin repertoires remain unclear. Here, we used single-cell full-length RNA-seq and B-cell receptor reconstruction to simultaneously assess the phenotypes, isotypes, constant region polymorphisms, and the paired heavy- and light-chain repertoires in intrathecal B cells. We detected extensive clonal connections between the memory B cell and antibody-secreting cell compartments and observed clonally related cells of different isotypes, including IgM/IgG1, IgG1/IgA1, IgG1/IgG2, and IgM/IgA1. There was a strong dominance of the G1m1 allotype constant region polymorphisms in antibody-secreting cells, but not in memory B cells. Tightly linked to the G1m1 allotype, we found a preferential pairing of the immunoglobulin heavy-chain variable (IGHV)4 gene family with the κ variable (IGKV)1 gene family. The IGHV4-39 gene was most used and showed the highest frequency of pairing with IGKV1-5 and IGKV1(D)-33. These results link IgG constant region polymorphisms to stereotyped B-cell responses in MS and indicate that the intrathecal B-cell response in these patients could be directed against structurally similar epitopes.
Study
EGAS00001005745
Human inflammatory cardiomyopathies following SARS-CoV2 infection and COVID-19 vaccination
Title: The cellular and molecular responses in human inflammatory cardiomyopathies following SARS-CoV2 infection and COVID-19 vaccination.
Abstract: Abstract: Myocarditis is a cardiac disorder with multiple etiologies characterised by inflammatory cell infiltration and can occur after SARS-CoV-2 infection or rarely following mRNA-based COVID-19 vaccination. The underlying cellular and molecular mechanisms driving these pathologies remain poorly understood.Here we performed single-nucleus-RNA-sequencing in left ventricular endomyocardial biopsies from patients with Non-COVID-19 myocarditis, following SARS-CoV-2 infection (Post-COVID-19) and COVID-19 vaccination (Post-Vaccination). We detected specific cytokine expression patterns highlighting a particular role of interferon-γ in Post-COVID-19 and upregulated IL16 and IL18 expression as a Post-Vaccination hallmark. While the myeloid response was similar between groups, CD4+T-cell proportions were higher in Post-Vaccination and cytotoxic CD8+T and NK cells expanded in Post-COVID-19. Endothelial cells showed gene expression changes suggestive of vascular barrier function deficiency in Post-COVID-19 and angiogenesis response to cardiac inflammation in all groups. Together, our results illuminate shared and distinct cellular and molecular architectures of Non-COVID-19, Post-COVID-19 and Post-Vaccination associated myocardial inflammation in human hearts.
Study
EGAS50000000769
Pharmacological improvement of CFTR function rescues airway epithelial homeostasis and host defense in cystic fibrosis children
Rationale: Recent clinical trials have shown that elexacaftor/tezacaftor/ivacaftor (ETI) provides significant benefit to patients with cystic fibrosis (CF) by improving CFTR function. Despite these promising clinical findings, the specific effects on the airway inflammatory status leading to structural damage and impaired lung function, remain elusive.
Objectives: We investigated the transcriptional changes at the single cell level of airway epithelial and immune cells that underlie the clinical improvement by ETI therapy in children with CF.
Methods: Nasal swabs from thirteen children with CF and at least one F508del allele aged 6 to 12 years were collected at baseline and three months after initiation of ETI and subjected to scRNA-seq. In addition, we collected nasal swabs from 12 age- and sex-matched controls. Sweat chloride concentrations, spirometry and multiple breath washout were used for clinical evaluation of CF children.
Measurements and main results: ETI significantly reduced sweat chloride concentrations (-52.2 ± 14.3 mmol/L, P < 0.001) and improved the lung clearance index (-1.3 ± 1.8, P < 0.05). Single cell transcriptomics revealed an impaired interferon signalling in epithelial cells of CF children at baseline, which was partially restored by ETI in conjunction with an ETI-induced increase in expression of MHC I and II encoding genes similar to control levels. Additionally, ETI markedly reduced the inflammatory phenotype of immune cells, particularly of neutrophils and macrophages.
Conclusions: Improvement of CFTR function by ETI restores epithelial homeostasis and reduces immune cell inflammatory responses in the upper airways of children with CF, highlighting the potential of early initiation of ETI therapy.
Study
EGAS50000000128
Polymorphisms in the mitochondrial genome are associated with bullous pemphigoid in Germans
Bullous pemphigoid (BP) is the most prevalent autoimmune skin blistering disease and is characterized by the generation of autoantibodies against the hemidesmosomal proteins BP180 (type XVII collagen) and BP230. Most intriguingly, BP is distinct from other autoimmune diseases because it predominantly affects elderly individuals above the age of 75 years, raising the question why autoantibodies and the clinical lesions of BP emerges mostly in this later stage of life, even in individuals harboring known putative BP-associated germline gene variants. The mitochondrial genome (mtDNA) is a potential candidate to provide additional insights into the BP etiology; however, the mtDNA has not been extensively explored to date. Therefore, we sequenced the whole mtDNA of German BP patients (n=180) and age- and sex-matched healthy controls (n=188) using next generation sequencing (NGS) technology, followed by the replication study using Sanger sequencing of an additional independent BP (n=89) and control cohort (n=104). While the BP and control groups showed comparable mitochondrial haplogroup distributions, the haplogroup T exhibited a tendency of higher frequency
in BP patients suffering from neurodegenerative diseases (ND) compared to BP patients without ND (p= 0.1448, Fisher’s exact test). A total of four single nucleotide polymorphisms (SNPs) in the mtDNA, namely, m.16263T>C, m.11914G>A, m.16051A>G, and m.16162A>G, were found to be significantly associated with BP based on the meta-analysis of our NGS data and the Sanger sequencing data (p=0.0017, p=0.0132, p=0.0129, and p=0.0076, respectively, Peto’s test). In summary, our study is the first to interrogate the whole mtDNA in BP patients and controls and to implicate multiple novel mtDNA variants in disease susceptibility. Studies using larger cohorts and more diverse populations are warranted to explore the functional consequences of the mtDNA variants identified in this study on immune and skin cells to understand their contributions to BP pathology.
Study
EGAS00001003932
BAMSE (Swedish abbreviation for Children, Allergy, Milieu, Stockholm, Epidemiology)
The BAMSE (Swedish abbreviation for Children, Allergy, Milieu, Stockholm, Epidemiology) study is an ongoing longitudinal, population-based prospective birth cohort including 4,089 children born between 1994 and 1996 in Stockholm, Sweden. The cohort was initially designed to study risk factors for asthma, allergic diseases and lung function in childhood, and to study factors of importance for prognosis at already established disease.Questionnaires on respiratory symptoms and medication were answered at age of 1, 2, 4, 8 and 16 years. Response rates ranged from 96-82% at each occasion with very minor selection bias over the years. Exposure to air pollutants and other environmental factors has been mapped since birth.At the 8 and 16 year follow-up, spirometry and FeNO measurements were performed and at the latter, impulse oscillometry was measured. Blood samples (including plasma) from around 2,500 children were taken at 4, 8 and 16 years and have been analyzed for different IgE-ab and biomarkers. Genome-wide genetic, global methylation and transcriptomic data exist on a subset of the children.
Study
EGAS00001002746
Duplexseq_of_the_interstrand_crosslinks_WGS
One of the most dangerous forms of DNA damage are interstrand crosslinks (ICLs), which covalently crosslink the two strands of the DNA double helix. The repair of these lesions is crucial for cellular survival due to their ability to block transcription and DNA replication. Initially, the major pathway that has been described in ICL repair involves a network of 22 genes that are mutated in a severe human genetic disease known as Fanconi Anemia (FA).
Using synthetic lethality screens in the near-haploid human HAP1 cell line, we recently identified two potentially novel regulators of ICL repair, C1orf112 and THAP12. Loss of C1orf112 and THAP12 causes hypersensitivity to ICL-inducing DNA damaging agents, such as Mitomycin C (MMC). Additionally, C1orf112-depleted cells show elevated levels of micronuclei and accumulation of DNA damage in S-phase. To better understand how C1orf112 and THAP12 mediate the repair of ICLs, we want to perform mutational signature analysis, using the BotSeq method. Therefore, WT, C1orf112 and THAP12 knockout cells were cultured in vehicle or MMC treated conditions for 10 days and the genomic DNA was isolated. FANCA and FANCD2 knockout cells are taken along as controls in this experimental setting.
Study
EGAS00001006545
Genomic_characterisation_of_MGUS__
he hematological malignancy multiple myeloma (MM), also called Kahler’s disease or plasma cell (PC) myeloma, is characterized by a clonal expansion of PCs originating in the bone marrow (BM). The expansion of these cells leads to an overproduction of antibodies and results in typical symptoms such as anemia, renal failure and bone lesions. All cases of MM are preceded by the asymptomatic, non-malignant pre-stage monoclonal gammopathy of undetermined significance (MGUS). Of all MGUS patients, only 1% per year will progress to MM. Despite efforts to elucidate the molecular mechanisms underlying the MGUS-to-MM progression, its pathogenesis still remains largely unknown. Additionally, the genetic profiles of MGUS patients have only been limitedly investigated due to the only incidental finding of MGUS, the difficulties in BM sampling and isolating a sufficient number of aberrant PCs from the BM aspirates of MGUS patients. Consequently, reliable biomarkers to individually predict which MGUS patients will progress to MM and which will not, are lacking. Therefore, it is highly required to study the molecular pathogenesis of MGUS and the role of genetic events in relation to the malignant transformation to MM.
Study
EGAS00001004124
16S rRNA gene amplification and maternal factors
Human breast milk contains a diverse community of bacteria but factors that produce variation in the breast milk microbiome are largely unknown. We evaluated if 1) maternal factors including breastfeeding practices modified the diversity and abundance of bacterial communities in breast milk and 2) if subclinical mastitis (SCM), an asymptomatic inflammatory condition occurring during lactation, induced a distinctive microbiota signature.
Study
EGAS00001003044
