Browsing by Subject "Endoglin"

Now showing 1 - 3 of 3
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    Mutational and phenotypic characterization of hereditary hemorrhagic telangiectasia
    (American Society of Hematology, 2020-10-22) Shovlin, Claire L.; Simeoni, Ilenia; Downes, Kate; Frazer, Zoe C.; Megy, Karyn; Bernabeu-Herrero, Maria E.; Shurr, Abigail; Brimley, Jennifer; Patel, Dilipkumar; Kell, Loren; Stephens, Jonathan; Turbin, Isobel G.; Aldred, Micheala A.; Penkett, Christopher J.; Ouwehand, Willem H.; Jovine, Luca; Turro, Ernest; Medicine, School of Medicine
    Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplasia. Care delivery for HHT patients is impeded by the need for laborious, repeated phenotyping and gaps in knowledge regarding the relationships between causal DNA variants in ENG, ACVRL1, SMAD4 and GDF2, and clinical manifestations. To address this, we analyzed DNA samples from 183 previously uncharacterized, unrelated HHT and suspected HHT cases using the ThromboGenomics high-throughput sequencing platform. We identified 127 rare variants across 168 heterozygous genotypes. Applying modified American College of Medical Genetics and Genomics Guidelines, 106 variants were classified as pathogenic/likely pathogenic and 21 as nonpathogenic (variant of uncertain significance/benign). Unlike the protein products of ACVRL1 and SMAD4, the extracellular ENG amino acids are not strongly conserved. Our inferences of the functional consequences of causal variants in ENG were therefore informed by the crystal structure of endoglin. We then compared the accuracy of predictions of the causal gene blinded to the genetic data using 2 approaches: subjective clinical predictions and statistical predictions based on 8 Human Phenotype Ontology terms. Both approaches had some predictive power, but they were insufficiently accurate to be used clinically, without genetic testing. The distributions of red cell indices differed by causal gene but not sufficiently for clinical use in isolation from genetic data. We conclude that parallel sequencing of the 4 known HHT genes, multidisciplinary team review of variant calls in the context of detailed clinical information, and statistical and structural modeling improve the prognostication and treatment of HHT.
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    Mutations causing premature termination codons discriminate and generate cellular and clinical variability in HHT
    (American Society of Hematology, 2024) Bernabéu-Herrero, Maria E.; Patel, Dilipkumar; Bielowka, Adrianna; Zhu, JiaYi; Jain, Kinshuk; Mackay, Ian S.; Chaves Guerrero, Patricia; Emanuelli, Giulia; Jovine, Luca; Noseda, Michela; Marciniak, Stefan J.; Aldred, Micheala A.; Shovlin, Claire L.; Medicine, School of Medicine
    For monogenic diseases caused by pathogenic loss-of-function DNA variants, attention focuses on dysregulated gene-specific pathways, usually considering molecular subtypes together within causal genes. To better understand phenotypic variability in hereditary hemorrhagic telangiectasia (HHT), we subcategorized pathogenic DNA variants in ENG/endoglin, ACVRL1/ALK1, and SMAD4 if they generated premature termination codons (PTCs) subject to nonsense-mediated decay. In 3 patient cohorts, a PTC-based classification system explained some previously puzzling hemorrhage variability. In blood outgrowth endothelial cells (BOECs) derived from patients with ACVRL1+/PTC, ENG+/PTC, and SMAD4+/PTC genotypes, PTC-containing RNA transcripts persisted at low levels (8%-23% expected, varying between replicate cultures); genes differentially expressed to Bonferroni P < .05 in HHT+/PTC BOECs clustered significantly only to generic protein terms (isopeptide-bond/ubiquitin-like conjugation) and pulse-chase experiments detected subtle protein maturation differences but no evidence for PTC-truncated protein. BOECs displaying highest PTC persistence were discriminated in unsupervised hierarchical clustering of near-invariant housekeeper genes, with patterns compatible with higher cellular stress in BOECs with >11% PTC persistence. To test directionality, we used a HeLa reporter system to detect induction of activating transcription factor 4 (ATF4), which controls expression of stress-adaptive genes, and showed that ENG Q436X but not ENG R93X directly induced ATF4. AlphaFold accurately modeled relevant ENG domains, with AlphaMissense suggesting that readthrough substitutions would be benign for ENG R93X and other less rare ENG nonsense variants but more damaging for Q436X. We conclude that PTCs should be distinguished from other loss-of-function variants, PTC transcript levels increase in stressed cells, and readthrough proteins and mechanisms provide promising research avenues.
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    Serum Soluble Endoglin in Pediatric Septic Shock Associated Multiple Organ Dysfunction Syndrome
    (Wolters Kluwer, 2023) Atreya, Mihir R.; Cvijanovich, Natalie Z.; Fitzgerald, Julie C.; Weiss, Scott L.; Bigham, Michael T.; Jain, Parag N.; Schwarz, Adam J.; Lutfi, Riad; Nowak, Jeffrey; Thomas, Neal J.; Quasney, Michael; Haileselassie, Bereketeab; Baines, Torrey D.; Zingarelli, Basilia; Genomics of Pediatric Septic Shock Investigators; Pediatrics, School of Medicine
    Background: Endothelial activation is a key driver of multiple organ dysfunction syndrome (MODS). Soluble endoglin (sENG) is expressed by mature and progenitor endothelial cells and thought to have angiogenic properties. We sought to determine the association between sENG and pediatric sepsis associated MODS. Methods: Prospective observational study of pediatric septic shock. Primary outcome of interest was complicated course -a composite of death by (or) MODS on day 7 of illness. Secondary outcomes included individual organ dysfunctions. Endothelial biomarkers including sENG were measured using multiplex Luminex assays among patients with existing data on pediatric sepsis biomarker risk model data (PERSEVERE-II). Multivariable regression was used to test the independent association between sENG and clinical outcomes. Serum sENG concentrations across PERSEVERE-II mortality risk strata and correlations with established markers of endothelial dysfunction. Results: 306 critically ill children with septic shock were included. Serum sENG concentrations were higher among those with primary and secondary outcomes of interest, with the exception of acute neurological dysfunction. sENG was independently associated with increased odds of complicated course [adj OR 1.53 (95% CI: 1.02–2.27), p=0.038] and acute renal dysfunction [adj OR 1.84 (95%CI: 1.18–2.876), p=0.006]. sENG demonstrated graded responses across PERSEVERE-II risk strata and was positively correlated with endothelial biomarkers, except Angiopoietin-1. Conclusions: Serum soluble endoglin is independently associated with complicated course and acute renal dysfunction in pediatric septic shock. Future studies are required to validate our observational data and mechanistic studies are necessary to elucidate whether endoglin plays a organ-specific role in development or resolution of acute renal dysfunction in sepsis.