Project description:Cerebral small vessel disease (SVD) is a prevalent disease of aging and a major contributor to stroke and dementia. The most commonly inherited SVD, CADASIL, is caused by dominantly acting cysteine-altering mutations in NOTCH3. These mutations change the number of cysteines from an even to an odd number, but the impact of these alterations on NOTCH3 protein structure remain unclear. Here, we prepared wildtype and four mutant recombinant NOTCH3 protein fragments to analyze the impact of CADASIL mutations on oligomerization, thiol status, and protein stability. Using gel electrophoresis, tandem MS/MS, and collision-induced unfolding, we find that NOTCH3 mutant proteins feature increased amounts of inappropriate disulfide bridges, reduced cysteines, and structural instability. Presence of a second protein factor, an N-terminal fragment of NOTCH3 (NTF), is capable of further altering disulfide statuses of both wildtype and mutant proteins, leading to increased numbers of reduced cysteines and further destabilization of NOTCH3 structure. In sum, these studies identify specific cysteine residues alterations and quaternary structure induced by CADASIL mutations in NOTCH3; further, we validate that reductive factors alter the structure and stability of this small vessel disease protein.
Project description:Exon expression profiling was performed on 37 clinical DLBCL samples and subsequently analyzed using alternative splice analysis of vairance (asANOVA) implemented in Partek Genomics Suite in order to identify alternative spliced genes. Diffuse large B-cell lymphoma (DLBCL) is a very heterogeneous malignant disease with diverse clinical presentation, outcome, and pathogenic mechanism. In order to better risk stratify patients there is a current need to find and validate new biomarkers of the disease. An alternatively spliced transcript of NOTCH3 missing exon 16 was identified and displayed prognostic and predictive biomarker potential.
Project description:Loss of arterial smooth muscle cells (SMCs) and abnormal accumulation of the extracellular domain of the NOTCH3 (Notch3ECD) receptor are the two core features of CADASIL, the most common genetic cerebral small vessel disease. Although CADASIL is known to be caused by highly stereotyped dominant mutations in NOTCH3, the relationship between NOTCH3 receptor activity, Notch3ECD accumulation and arterial SMC loss has remained elusive, hampering the development of disease-modifying therapies. Using novel histopathological and multiscale imaging modalities, we quantified previously undetectable CADASIL-driven focal arterial SMC loss in the central nervous system of mice expressing the archetypal Arg169Cys CADASIL mutation. Notably, we found more severe arterial pathology and greater Notch3ECD accumulation in transgenic model mice overexpressing the mutation on a homozygous wild-type Notch3 background (TgNotch3R169C) than in knock-in model Notch3R170C/R170C mice expressing this mutation without a wild-type Notch3 copy. We further showed that wild-type Notch3ECD co-aggregated with mutant Notch3ECD and that elimination of one copy of wild-type Notch3 in TgNotch3R169C mice was sufficient to attenuate Notch3ECD accumulation and arterial pathology. Importantly, RNA sequencing revealed no substantial change in the expression of Notch3-regulated genes in TgNotch3R169C brain arteries. Collectively, our results provide compelling evidence that Notch3ECD accumulation, involving mutant and wild-type NOTCH3, and not aberrant NOTCH3 signaling, is the key driver of arterial SMC loss in CADASIL, thus identifying NOTCH3-lowering approaches as candidate therapeutic strategies.
Project description:Wilson’s disease (WD) is a relevant human genetic disease caused by mutations in the ATP7B gene, whose product is a liver enzyme responsible for copper export into bile and blood. Interestingly, the spectrum of ATP7B mutations is vast and can influence clinical presentation (a variable spectrum of hepatic and neural manifestations), though the reason for this is not well understood. Here we describe the successful generation of iPSCs from a Chinese patient with Wilson’s disease that bears the R778L Chinese hotspot mutation in the ATP7B gene.
Project description:Gene expression profiling was performed for 7 DLBCL primary clinical samples and assignment of activated B-cell-like(ABC)/germinal center B-cell-like (GCB) DLBCL classes, B-cell-associated gene signature (BAGS), and a probability of response to vincristine was performed for each sample. Diffuse large B-cell lymphoma (DLBCL) is a very heterogeneous malignant disease with diverse clinical presentation, outcome, and pathogenic mechanism. In order to better risk stratify patients there is a current need to find and validate new biomarkers of the disease. An alternatively spliced transcript of NOTCH3 missing exon 16 was identified and displayed prognostic and predictive biomarker potential.
Project description:Severe combined immunodeficiency 8 (IMD8) is caused by mutations in the human Coronin 1A (Coro1A). The clinical presentation of IMD8 patients is characterized by recurrent bacterial infections, suggesting an important role of Coro1A in innate immunity. To analyze the molecular mechanism of Coro1A during neutrophil recruitment, we identified the Coro1A interactome by conducting co-immunoprecipitation (Co-IP) experiments using GFP NanoTrap technology and subsequent mass spectrometry (LC-MS/MS) using human neutrophil-like differentiated HL-60 (dHL-60) cells stably expressing Coro1A-EGFP (dHL-60-Coro1A-EGFP) cells.
Project description:While most cases of vascular dementia represent complex interactions between host genetics and environmental factors, mendelian forms of vascular dementia also exist. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), is a mendelian disease characterized by progressive vascular deterioration, cognitive deficits, and strokes. Mutations in the NOTCH3 receptor underlies the pathologies in CADASIL. NOTCH3 is primarily expressed in vascular smooth muscle cell (vSMC) and its’ expression is critical for differentiation and functional integrity of arterial vSMCs, albeit through unclear mechanism(s). To elucidate the contribution of NOTCH3 in the maintenance of cerebral vascular architecture and function, we performed micro-computed tomography (micro-CT) on the brains of aged Notch3-deficient animals. Micro-CT assessment of the cerebral vasculature architecture showed significant abnormalities including severe vessel dilation and tortuosity (dolicoectasia) of the middle cerebral artery and its branches in the Notch3-/- compared to aged-match controls. To identify the molecular pathway from NOTCH3 dysregulation to the observed cerebral vascular dysfunction, we performed single-cell RNASeq on cerebral arteries isolated from young (4w) and old (104w) Notch3-/- animals. Evaluation of the vSMC-specific transcriptomes indicated significant loss of proteins associated with muscle contraction and increased extracellular matrix production in animals that lack NOTCH3. Using a combination of immunofluorescence microscopy and in vitro functional assays, we confirmed that continued expression of Notch3 is a critical requirement for maintenance of vSMC contractile function. Impaired contractility also affected flow of cerebrospinal fluid in the parenchyma of Notch3-/- . MRI and behavioral assessments were performed in the Notch3-/- animals to elucidate the relationship between impaired vascular contractility to cognitive function. Taken together these findings link the molecular dysfunction of NOTCH3 through its regulation of vascular contractility and cerebral vessel architecture to altered neurological function and clarify the molecular pathways to cellular pathology of Notch3 driven dementias.
Project description:Notch3 is a transmembrane receptor which is critically important for the structure and myogenic response of distal arteries, particularly cerebral arteries. After activation of the receptor, the intracellular domain translocates in the nucleus to activate target genes transcription. In order to identify Notch3 target genes, we used microarrays to compare gene expression from caudal arteries (Notch3+/+ vs Notch3-/-) and selected down-regulated genes in Notch3-/- arteries. Caudal arteries were dissected from 1 month old Notch3+/+ and Notch3-/- mice. RNA was prepared with arteries pooled from three (AJ_N3WT_3, AJ_N3WT_4) or four (AJ_N3WT_1, AJ_N3KO_1, AJ_N3KO_2, AJ_N3KO_4) mice and hybridized on Mouse MOE430.2 Affymetrix chips. For each group (Notch3+/+ and Notch3-/-), three biological replicates were performed.
Project description:Wilson’s disease (WD) is a relevant human genetic disease caused by mutations in the ATP7B gene, whose product is a liver enzyme responsible for copper export into bile and blood. Interestingly, the spectrum of ATP7B mutations is vast and can influence clinical presentation (a variable spectrum of hepatic and neural manifestations), though the reason for this is not well understood. Here we describe the successful generation of iPSCs from a Chinese patient with Wilson’s disease that bears the R778L Chinese hotspot mutation in the ATP7B gene. Global gene expression profiling with DNA microarrays showed that WD iPSCs cluster together with human ESCs (H9) compared to donor fibroblasts. WD patient fibroblasts were isolated and expanded from a dermal biopsy of a middle age Chinese Han male, WD iPSCs were generated by overexpression of human Oct4/Sox2/Klf4/c-Myc in WD fibroblasts and expanded on Matrigel with mTESR1 culture medium. For DNA microarray analysis, WD fibroblasts (passage 5), 3 cell lines of WD iPSCs growing on Matrigel (passage 8) and human ES H9 growing on Matrigel (passage 40) were treated with Trizol, followed by RNA extraction and hybridization.
Project description:Molecular mechanisms underlying the differentiation of brain mural cells from neural crest are poorly understood. We found that activation of Notch3 signaling in human pluripotent stem cell-derived neural crest (using lentiviral overexpression of the human Notch3 intracellular domain, N3ICD) was sufficient to direct the differentiation of mural cells. We used Notch3 ChIP-sequencing to identify cis-regulatory elements directly bound by the Notch3 transcriptional activation complex in this system.