Project description:Mosaic-variegated aneuploidy (MVA) syndrome is a rare childhood disorder characterized by biallelic BUBR1, CEP57, or TRIP13 aberrations, increased chromosome missegregation, and a broad spectrum of clinical features, including various cancers, congenital defects, and progeroid pathologies. To investigate the mechanisms underlying this disorder and its phenotypic heterogeneity, we mimicked the BUBR1L1012P mutation in mice (BubR1L1002P) and combined it with two other MVA variants, BUBR1X753 and BUBR1H, generating a truncated protein and low amounts of wildtype protein, respectively. Whereas, BubR1X753/L1002P and BubR1H/X753 mice die prematurely, BubR1H/L1002P mice are viable and exhibit many MVA features, including cancer predisposition and various progeroid phenotypes, including short lifespan, dwarfism, lipodystrophy, sarcopenia, and low cardiac stress tolerance. Strikingly, although these mice had a similar reduction in total BubR1 and spectrum of MVA phenotypes as BubR1H/H mice, several progeroid pathologies were attenuated in severity, which in skeletal muscle coincided with reduced senescence-associated secretory phenotype (SASP) complexity. Additionally, mice harboring heterozygous BUBR1 MVA variants developed mild MVA pathologies later in life, with alleles conferring unique phenotypic profiles. Together, these data demonstrate that subtle BUBR1 allelic effects contribute to disease heterogeneity in both MVA patients and heterozygous carriers of MVA mutations, independent of aneuploidy rates and BUBR1 protein levels.
Project description:Mosaic-variegated aneuploidy (MVA) syndrome is a rare childhood disorder characterized by biallelic BUBR1, CEP57, or TRIP13 aberrations, increased chromosome missegregation, and a broad spectrum of clinical features, including various cancers, congenital defects, and progeroid pathologies. To investigate the mechanisms underlying this disorder and its phenotypic heterogeneity, we mimicked the BUBR1L1012P mutation in mice (BubR1L1002P) and combined it with two other MVA variants, BUBR1X753 and BUBR1H, generating a truncated protein and low amounts of wildtype protein, respectively. Whereas, BubR1X753/L1002P and BubR1H/X753 mice die prematurely, BubR1H/L1002P mice are viable and exhibit many MVA features, including cancer predisposition and various progeroid phenotypes, including short lifespan, dwarfism, lipodystrophy, sarcopenia, and low cardiac stress tolerance. Strikingly, although these mice had a similar reduction in total BubR1 and spectrum of MVA phenotypes as BubR1H/H mice, several progeroid pathologies were attenuated in severity, which in skeletal muscle coincided with reduced senescence-associated secretory phenotype (SASP) complexity. Additionally, mice harboring heterozygous BUBR1 MVA variants developed mild MVA pathologies later in life, with alleles conferring unique phenotypic profiles. Together, these data demonstrate that subtle BUBR1 allelic effects contribute to disease heterogeneity in both MVA patients and heterozygous carriers of MVA mutations, independent of aneuploidy rates and BUBR1 protein levels.
Project description:We investigated the cause of gastrointestinal neoplasia in a man who developed adenocarcinoma of the ampulla of Vater at the age of 34, followed almost three decades later by adenomatous polyps and invasive adenocarcinomas of both the colon and stomach. Premature chromatid separation, mosaic variegated aneuploidy (MVA), combined with structural chromosome abnormalities were detected in his cells. We identified a homozygous intronic mutation, c.2386-11A>G in BUB1B which creates a de novo splice site that is favored over the authentic site. This study expands the phenotype of BUB1B mutations and MVA to include common adult-onset cancers and provides evidence for the interdependency of APC and BUBR1 proteins in humans.
Project description:We investigated the cause of gastrointestinal neoplasia in a man who developed adenocarcinoma of the ampulla of Vater at the age of 34, followed almost three decades later by adenomatous polyps and invasive adenocarcinomas of both the colon and stomach. Premature chromatid separation, mosaic variegated aneuploidy (MVA), combined with structural chromosome abnormalities were detected in his cells. We identified a homozygous intronic mutation, c.2386-11A>G in BUB1B which creates a de novo splice site that is favored over the authentic site. This study expands the phenotype of BUB1B mutations and MVA to include common adult-onset cancers and provides evidence for the interdependency of APC and BUBR1 proteins in humans. 2 biological replicates of 7 samples (lymphoblastoid cell line (LCL) of the affected proband, fibroblasts of the affected proband, LCLs from 2 relatives of the proband, LCLs from 2 unaffected controls, fibroblasts from 1 control) were processed at the same time.
Project description:Phenotypic heterogeneity in monogenic neurodevelopmental disorders can arise from differential severity of variants underlying disease, but how distinct alleles drive variable disease presentation is not well understood. Here, we investigate missense mutations in DNMT3A, a DNA methyltransferase associated with overgrowth, intellectual disability, and autism, to uncover molecular correlates of phenotypic heterogeneity. We generate a DNMT3A P900L/+ mouse mimicking a mutation with mild-to-moderate severity, and compare phenotypic and epigenomic effects with a severe R878H mutation. P900L mutants exhibit core growth and behavioral phenotypes shared across models but show subtle epigenomic changes, while R878H mutants display extensive disruptions. We identify mutation-specific dysregulated genes which may contribute to variable disease severity. Shared transcriptomic disruption identified across mutations overlaps dysregulation observed in other developmental disorder models and likely drives common phenotypes. Together, our findings define central drivers of DNMT3A disorders and illustrate how variable epigenomic disruption contributes to phenotypic heterogeneity in neurodevelopmental disease.
Project description:Phenotypic variability is a hallmark of diseases involving chromosome gains and losses, such as Down Syndrome and cancer. Allelic variances have been thought to be the sole cause of this heterogeneity. Here, we systematically examine the consequences of gaining and losing single or multiple chromosomes to show that the aneuploid state causes non-genetic phenotypic variability. Yeast cell populations harboring the same defined aneuploidy exhibit heterogeneity in cell cycle progression and response to environmental perturbations, which we show to be partly due to gene copy number imbalances. Thus, subtle changes in gene expression severely impact the robustness of biological networks and cause alternate behaviors when they occur at a large scale. Because trisomic mice also exhibit variable phenotypes, we further propose that non-genetic individuality is a universal characteristic of the aneuploid state that could contribute to variability in presentation and treatment responses of diseases caused by aneuploidy.
Project description:Denys-Drash syndrom is a rare disease. We used single cell RNA sequencing (scRNA-seq) to analyze the diversity of kidney tissue cells in an infant with Denys-Drash syndrom.
Project description:This study aimed to analyze the transcriptional profiles of ChAdOx/MVA vaccine induced P1A-35-43-specific CD8+ T-cells and how this is affected by both tissue location and anti-PD-1 treatment. 15V4T3 tumour-bearing DBA/2 mice were vaccinated with ChAdOx/MVA P1A with or without anti-PD-1 treatment. Following treatment, spleens and tumours were collected, processed to single-cell suspension and P1A-35-43-specific CD8+ T-cells were then isolated by MHC-class I multimer staining and FACS. Single-cell RNA-seq experiments were performed using the 10X Genomics platform to analyze P1A-specific CD8+ T-cell transcriptional profiles. Results of this transcriptomic analysis showed that cells segregated into distinct phenotypic subtypes reflecting either effector or stem-like states, the distribution of which was dependent on tissue of origin and treatment status. These results provide an in depth phenotypic analysis of MAGE-type-antigen-specific CD8+ T-cells induced by ChAdOx/MVA vaccination and how phenotype is influenced by physiological location and immune checkpoint blockade treatment.