Publications by authors named "Knowles M"

Rationale: Chronic () airway infection is common and a key contributor to diminished lung function and early mortality in persons with cystic fibrosis (PwCF). Risk factors for chronic among PwCF include cystic fibrosis transmembrane conductance regulator genotype, genetic modifiers, and environmental factors. Intensive antibiotic therapy and highly effective modulators do not eradicate in most adolescents and adults with cystic fibrosis.

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Several studies have now described instances where G-rich sequences in promoters and enhancers regulate gene expression through forming G-quadruplex (G4) structures. Relatedly, our group recently identified 301 long genomic stretches significantly enriched for minimal G4 motifs (LG4s) in humans and found the majority of these overlap annotated enhancers, and furthermore, that the promoters regulated by these LG4 enhancers are similarly enriched with G4-capable sequences. While the generally accepted model for enhancer:promoter specificity maintains that interactions are dictated by enhancer- and promoter-bound transcriptional activator proteins, the current study tested an alternative hypothesis: that LG4 enhancers interact with cognate promoters via a direct G4:G4 DNA-based mechanism.

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Article Synopsis
  • - A study evaluated the management of primary ciliary dyskinesia (PCD) in pediatric participants using a multicenter, observational approach, collecting data on therapy types and their annual usage.
  • - Over 137 participants were monitored for 13 years, finding that nearly all received antibiotics, with a significant number using cephalosporins and chronic azithromycin, and older patients tended to utilize more therapies.
  • - Results indicated that therapy usage varies significantly, often correlating with age and specific types of ciliary defects, highlighting the need for more disease-specific research to better understand the effectiveness of these treatments.
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Article Synopsis
  • PCD (Primary Ciliary Dyskinesia) and CF (Cystic Fibrosis) are both genetic diseases that affect how the lungs work and cause issues from a young age, but PCD is thought to be milder, even though evidence is limited.
  • The study wanted to see how children with PCD compare to those with CF in terms of health over time, especially focusing on children with certain severe forms of PCD.
  • They found that kids with PCD and the severe type had lower lung function than kids with CF, but their nutrition was similar, with more CF kids getting sick from bacteria in their lungs than PCD kids.
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Variation in the non-coding genome represents an understudied mechanism of disease and it remains challenging to predict if single nucleotide variants, small insertions and deletions, or structural variants in non-coding genomic regions will be detrimental. Our approach using complementary RNA-seq and targeted long-read DNA sequencing can prioritize identification of non-coding variants that lead to disease via alteration of gene splicing or expression. We have identified a patient with primary ciliary dyskinesia with a pathogenic coding variant on one allele of the SPAG1 gene, while the second allele appears normal by whole exome sequencing despite an autosomal recessive inheritance pattern.

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To identify modifier loci underlying variation in body mass index (BMI) in persons with cystic fibrosis (pwCF), we performed a genome-wide association study (GWAS). Utilizing longitudinal height and weight data, along with demographic information and covariates from 4,393 pwCF, we calculated AvgBMIz representing the average of per-quarter BMI Z scores. The GWAS incorporated 9.

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Background: Although wearable technology has become increasingly common, comprehensive studies examining its ownership across different sociodemographic groups are limited.

Objective: The aims of this study were to (1) measure wearable device ownership by sociodemographic characteristics in a cohort of US consumers and (2) investigate how these devices are acquired and used for health-related purposes.

Methods: Data from the Rock Health Digital Health Consumer Adoption Survey collected from 2020 to 2022 with 23,974 US participants were analyzed.

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Background: Cystic fibrosis (CF) is caused by deleterious variants in each CFTR gene. We investigated the utility of whole-gene CFTR sequencing when fewer than two pathogenic or likely pathogenic (P/LP) variants were detected by conventional testing (sequencing of exons and flanking introns) of CFTR.

Methods: Individuals with features of CF and a CF-diagnostic sweat chloride concentration with zero or one P/LP variants identified by conventional testing enrolled in the CF Mutation Analysis Program (MAP) underwent whole-gene CFTR sequencing.

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Article Synopsis
  • Tubulin is a key component of the cytoskeleton and has various isotypes in animals, but it's unclear how these isotypes influence microtubule structures in different cell types.
  • Research on 12 patients with primary ciliary dyskinesia and mouse models uncovered variants in the tubulin isotype that disrupted the formation of centrioles and cilia, impacting microtubule dynamics.
  • The study identified different variants causing distinct effects on tubulin interactions, allowing for the classification of patients into three types of ciliopathic diseases, highlighting the unique roles of specific tubulin isotypes in cellular functions.
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Since genotype imputation was introduced, researchers have been relying on the estimated imputation quality from imputation software to perform post-imputation quality control (QC). However, this quality estimate (denoted as Rsq) performs less well for lower-frequency variants. We recently published MagicalRsq, a machine-learning-based imputation quality calibration, which leverages additional typed markers from the same cohort and outperforms Rsq as a QC metric.

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Bronchiectasis is a pathological dilatation of the bronchi in the respiratory airways associated with environmental or genetic causes (e.g., cystic fibrosis, primary ciliary dyskinesia, and primary immunodeficiency disorders), but most cases remain idiopathic.

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Article Synopsis
  • - The study aims to uncover genetic factors contributing to severe cystic fibrosis liver disease (CFLD) since it affects only about 7% of individuals with cystic fibrosis (CF).
  • - Researchers analyzed whole-genome sequencing data from over 4,000 CF patients, finding significant associations with specific genetic variants related to CFLD, including the Z allele of SERPINA1 and several other genes.
  • - The findings suggest that severe CFLD is linked to various biological pathways, such as inflammation, immune response, and liver cell signaling, potentially leading to better understanding and treatment methods for the condition.
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Importance: Community health worker (CHW) programs may improve health outcomes, increase quality of life, and reduce hospitalizations and cost of care. However, knowledge is limited on the barriers and facilitators associated with scaling evidence-based CHW programs to maximize their public health outcomes.

Objective: To identify barriers and facilitators to implementing an evidence-based CHW model.

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The pancreatic ductal adenocarcinoma (PDAC) stroma and its inherent biophysical barriers to drug delivery are central to therapeutic resistance. This makes PDAC the most prevalent pancreatic cancer with poor prognosis. The chemotherapeutic drug gemcitabine is used against various solid tumours, including pancreatic cancer, but with only a modest effect on patient survival.

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Syntaxin1a (Syx1a) is essential for stimulated exocytosis in neuroendocrine cells. The vesicle docking process involves the formation of nanoscale Syx1a domains on the plasma membrane and the Syx1a clusters disintegrate during the fusion process. Syx1a nanodomains are static yet Syx1a molecules dynamically enter and leave the domains; the process by which these clusters maintain this balance is unclear.

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Phospholipase D1 (PLD1) activity is essential for the stimulated exocytosis of secretory vesicles where it acts as a lipid-modifying enzyme to produces phosphatidic acid (PA). PLD1 localizes to the plasma membrane and secretory vesicles, and PLD1 inhibition or knockdowns reduce the rate of fusion. However, temporal data resolving when and where PLD1 and PA are required during exocytosis is lacking.

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Background: Primary ciliary dyskinesia (PCD) is a rare disorder of motile cilia associated with situs abnormalities. At least 12% of patients with PCD have situs ambiguus (SA), including organ laterality defects falling outside normal arrangement (situs solitus [SS]) or mirror image inversion (situs inversus totalis [SIT]).

Research Question: Do patients with PCD and SA achieve worse clinical outcomes compared with those with SS or SIT?

Study Design And Methods: This cross-sectional, multicenter study evaluated participants aged 21 years or younger with PCD.

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Bladder cancer is a global health issue with sex differences in incidence and prognosis. Bladder cancer has distinct molecular subtypes with multiple pathogenic pathways depending on whether the disease is non-muscle invasive or muscle invasive. The mutational burden is higher in muscle-invasive than in non-muscle-invasive disease.

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Kinases are important therapeutic targets, and their inhibitors are classified according to their mechanism of action, which range from blocking ATP binding to covalent inhibition. Here, a mechanism of inhibition is highlighted by capturing p21-activated kinase 5 (PAK5) in an intermediate state of activation using an Affimer reagent that binds in the P+1 pocket. PAK5 was identified from a non-hypothesis-driven high-content imaging RNAi screen in urothelial cancer cells.

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Background: Mucociliary clearance is dysfunctional in people with primary ciliary dyskinesia, resulting in the accumulation of dehydrated mucus in the airways that is difficult to clear. We undertook a study to assess the benefit on lung function of treatment with a nebulised epithelial sodium channel (ENaC) blocker, idrevloride, with or without hypertonic saline, in people with primary ciliary dyskinesia.

Methods: The CLEAN-PCD trial was a phase 2, randomised, double-blind, placebo-controlled crossover trial conducted at 32 tertiary adult and paediatric care centres and university hospitals in Canada, Denmark, Germany, Italy, the Netherlands, Poland, the UK, and the USA.

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Background: Primary ciliary dyskinesia (PCD) is typically an autosomal recessive disease characterized by recurrent infections of the lower respiratory tract, frequent and severe otitis media, chronic rhinosinusitis, neonatal respiratory distress, and organ laterality defects. While severe lower respiratory tract infections and bronchiectasis are common in Inuit, PCD has not been recognized in this population.

Methods: We report a case series of seven Inuit patients with PCD identified by genetic testing in three Canadian PCD centers.

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C-reactive protein (CRP) is commonly measured as an inflammatory marker in patient studies for coronary heart disease, autoimmune disease and recent acute infections. Due to a correlation of CRP to a vast number of disease states, CRP is a well-studied protein in medical literature with over 16000 references in PubMed [1]. However, the biochemical and structural variations of CRP are not well understood in regards to their binding of complement immune response proteins.

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Community health workers (CHWs) have worked in a variety of settings in the United States for more than 70 years and are increasingly recognized as an essential health workforce. CHWs share life experience with the people they serve and have firsthand knowledge of the causes and impacts of health inequity. They provide a critical link between marginalized communities and health care and public health services.

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Lung disease is the major cause of morbidity and mortality in persons with cystic fibrosis (pwCF). Variability in CF lung disease has substantial non-CFTR (CF transmembrane conductance regulator) genetic influence. Identification of genetic modifiers has prognostic and therapeutic importance.

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