Charles Colin Thomas Hindmarch

Background: Canadian biomedical core facilities (BCFs) provide researchers with access to advanced tools and unique technical expertise, essential for research. However, their role, sustainability, and impact remain poorly understood. We report on the evolution of model and existing state of Canada’s 205 BCFs, examining challenges and benefits. Methods: Cross referencing of national databases by the Canadian Innovation Fund (CFI), and from data collected by the Canadian Network of Scientific Platforms (CNSP) allowed he identification of BCFs. Hand curation of these lists validated that cores are operational. To ensure cores not listed by CFI/CNSP were captured, research intensive institutions in Canada were independently searched to identify active cores. Results: There are currently 205 active and operational BCFs located across 9 provinces, which can be further stratified into 9 ‘technical domains’ that describe the nature of services they provide. Quebec (80 cores) and Ontario (75 cores) have the highest confluence of BCFs, with Quebec having a higher ratio of cores per capita. Conclusions: While our data establishes the ubiquity of Canadian BCFs, we highlight substantial challenges including sustainability, governance, evaluation and the recognition of support for core scientists. Here, we establish a framework to address these challenges and to inform best practice, to optimize creation of impactful, accessible and functional biomedical core facilities.

BACKGROUND: DRP1 (dynamin-related protein 1) mediates mitochondrial fission and permits rapid cell cycle progression in hyperproliferative cells by coordinating nuclear and mitochondrial division, a process called mitotic fission. However, DRP1 alone appears insufficient to complete fission, and the link between fission and cell cycle progression is unknown. We hypothesize that DNM2 (dynamin 2) interacts with DRP1 to complete mitochondrial fission and regulate cell cycle progression. We show that DNM2 is upregulated in pulmonary artery smooth muscle cells (PASMCs) in human and rodent pulmonary arterial hypertension (PAH), contributing to disease pathophysiology. METHODS: Mitochondrial morphology, protein colocalization, and fission were assessed using stimulated emission depletion microscopy, protein interactions by immunoprecipitation, and transcriptomics by RNA sequencing. DNM2 was quantified in PASMC and lungs from patients with PAH and rats with pulmonary hypertension (PH), induced by monocrotaline or sugen5416/hypoxia. siDNM2’s effects on cell proliferation, cell cycle progression, and apoptosis were assessed by flow cytometry. Single-cell RNA sequencing was performed on publicly available data sets. siDNM2 was nebulized to monocrotaline- and sugen5416/hypoxia-PH rats, and disease regression was quantified by cardiac catheterization and histology. RESULTS: DNM2 is increased in PAH PASMC. DNM2 interacts with DRP1 via its GTPase domain, permitting mitochondrial translocation and promoting fission. siDNM2 inhibits fission and cell proliferation and increases apoptosis. siDNM2 causes G1/G0 blockade by downregulating RGCC (regulator of cell cycle) with downstream effects on CDK (cyclin-dependent kinase) 4, cyclin D1, and p27 ^kip1 . Conversely, augmenting DNM2 in normal PASMC induces fission and accelerates proliferation. Upregulation of DNM2 in PAH is due to decreased miR-124-3p (microRNA-124-3p) and activation of STAT3 (signal transducer and activator of transcription 3). An miR-124-3p-STAT3-DNM2-DRP1-RGCC pathway accelerates mitotic fission and is upregulated in PASMC, airway epithelium, endothelial cells, fibroblasts, and macrophages in PAH. Nebulized siDNM2 regresses established PH in vivo in rats of both sexes. CONCLUSIONS: DNM2 is a mediator in the terminal steps of DRP1-dependent fission and constitutes a novel therapeutic target in PAH.

Pulmonary hypertension (PH) is a vasculopathy that results in elevated mean pulmonary arterial pressures over 20mmHg. Despite significant advances in research, PH still has a high mortality rate, and there is currently no cure for the disease. As with all biomedical fields, PH researchers have embraced the power of next generation technologies such as microarrays and RNA sequencing. Most of these data can be found on public repositories, which is usually a requirement for publication. While these repositories are rich sources of data, they require intermediate to advanced bioinformatics skills to access, download, and make these data useful. Here we present P ulmonary H ypertension E ngine for L inked E xperiments ( PHELEX ), which represents a comprehensive catalogue of all RNA sequencing data related to PH that is currently available on the Gene Expression Omnibus (GEO), hosted by the US National Centre for Biotechnology Information (NCBI). We identified 2,278 bulk RNA sequencing samples from human, mouse and rat, and built a searchable tool based on the metadata that is associated with each sample. PHELEX is a functional tool that allows selected studies to be highlighted, and parsed through Confidence, an analysis tool we have created, which will model the data based on user-defined classifiers, perform differential gene expression and pathway analysis, and present these data using standard graphics, and text-file results. PHELEX also allows PH researchers to cross-cut between discrete studies, facilitating de novo understanding of these data. As a robust searchable repository of genomic data, we hope that PHELEX will accelerate PH innovation and discovery, by allowing researchers to mine existing genomic data and thus better understand the molecular signatures that underpin PH.

RNA-seq quantifies the abundance of transcripts within a biological sample and performs differential analysis between different conditions to reveal regulated gene signatures. Three challenges exist: (1) different analytical packages can often report different expression patterns and false-discovery-rates and P-values; (2) the effective use of these analytical packages requires substantial knowledge of programming and bioinformatics; and (3) there are a lack of intuitive methods to prioritize target genes for further investigation. To address these challenges, we developed Confidence, a web-based application to perform simultaneous statistical analysis of RNA-seq count data. Confidence incorporates the Confidence Score (CS), ranging from 1 to 4 to aid in gene prioritization, where 1 represents low confidence and 4 represents high confidence. The Confidence web-based application was designed for rapid and intuitive analysis of standard experimental metadata and gene count inputs providing a web-based, ‘wide-net’ approach to RNA-seq analysis. Gene scoring allows for unbiased gene selection and identification of novel genes strongly associated with disease/treatment models across multiple species. Pathway analysis has been integrated so that highly confident genes can be placed into biological context. Confidence provides a new strategy for target prioritization in RNA-seq analysis and the generation of publication-quality figures, which we demonstrate here using a published database.

Background: Hypertension is a polygenic, complex disease that impacts men and women differently; whilst the incidence of high blood pressure (BP) is roughly equal over a lifetime, men typically are at higher risk of developing the disease earlier in life, before 50 years of age. There is adequate evidence that the brain is critical for the BP setpoint. The paraventricular nucleus (PVN) of the hypothalamus is an integrative structure that can influence not only neurohumoral responses to blood pressure changes, but also sympathetic drive. Here we manipulate the androgenic status of both male and female spontaneously hypertensive rats (SHRs) to determine how this changes gene expression within the PVN of these animals. Methods: SHR (8-weeks old) were either sham-operated or orchiectomized, whereas all females were oophorectomized, half of which received 10 mg testosterone propionate subcutaneously. Mean arterial pressure (MAP) and testosterone (T) were measured by carotid cannulation and ELISA respectively. Sequencing was performed on hand-punched PVN sections and subjected to robust bioinformatic analysis. Results: in total, 6,571 differentially regulated genes (DRGs) are regulated in the PVN of male and female rats. High T (endogenous or replaced) correlates with higher MAP in both sexes. Orchidectomy-induced T depletion resulted in the significant regulation of 5,104 genes, involved in thousands of biological roles, including ones related to hormone and sex-hormone signalling. In the female SHR, testosterone replacement in oophorectomized animals induced the regulation of 1,727 genes, sharing many biological functions with those in the high T males. We validated key genes by qPCR to determine false discovery rate. Conclusions: T status in hypertensive rats correlates with MAP, and consistent changes in PVN transcriptome.

Background and Aims: Multiple germline gene variants promote familial and idiopathic pulmonary arterial hypertension (PAH); however, none are consistently identified in associated PAH with connective tissue disease (APAH-CTD). Moreover, the role of somatic variants in genes mediating clonal haematopoiesis of indeterminate potential (CHIP) in PAH is unknown. Here, somatic and germline DNMT3A variants and CHIP gene variants in PAH were evaluated. Methods: Exome sequencing (ES) was compared between PAH Biobank participants (n = 1832 European ancestry/2572 total), vs. gnomAD controls (7509 European ancestry/141 456 total). Subsequently, targeted panel sequencing (TPS) of 22 CHIP genes, including DNMT3A, was performed in PAH (n = 1659) vs. controls (n = 3644). Somatic CHIP variants in the UK Biobank using ES (controls = 448 239; PAH = 2559) were also assessed. DNMT3A mRNA expression was measured in peripheral blood mononuclear cells (PBMCs) of patients with scleroderma APAH-CTD (n = 50), idiopathic PAH (n = 30), scleroderma without PAH (n = 19), and healthy controls (n = 41). Hemodynamic were evaluated in haematopoietic Dnmt3a-knockout mice. Results: Predicted deleterious germline DNMT3A variants were increased in subjects of European ancestry (6/1832) vs. controls (6/7509) (relative risk [RR] = 4.1, P = .018). In the entire PAH Biobank cohort (n = 2572), DNMT3A germline and somatic variants were further enriched (PAH: 1.28% vs. controls: .43%, P = 1.65 × 10−10). Eight DNMT3A mutations (.39%) were likely germline (female/male: 7/1) and 25 (.82%) likely somatic (female/male: 21/4), including 13/33 APAH-CTD participants. TPS identified CHIP in 242 PAH subjects (48% DNMT3A). DNMT3A- and all-CHIP variants were associated with PAH after correcting for age, sex, and age–CHIP interactions (odds ratio [OR]: 25.44, P = 4.50 × 10−5; OR: 23.35, P = 2.87 × 10−8, respectively). In the UK Biobank, CHIP mutations were increased in PAH (PAH = 5.35% vs. Control = 3.45%, P ≤ .0001). DNMT3A was reduced in PAH-PBMCs (area under curve [AUC] = .82) (P < .0001). Haematopoietic Dnmt3a-knockout in mice caused inflammatory PAH, which was attenuated by IL-1β antibody therapy. Conclusions: Germline DNMT3A variants and somatic variants of DNMT3A and CHIP genes increase the risk of PAH, including APAH-CTD, promote inflammation, and constitute potential biomarkers and therapeutic targets.

RNA sequencing (RNA-seq) is used to quantify transcript levels through measurement of nucleotide sequences. To evaluate statistically significant changes in gene expression, transcript counts between samples are compared using differential expression analysis methods. However, three of the most pressing challenges in transcriptomics analyses are: 1) analytical packages produce a distinct number of differentially expressed genes with varied P -value and fold-change values; 2) the effective use of these analytical packages requires substantial knowledge of programming and bioinformatics; and 3) there are a lack of intuitive methods to select target genes for further investigation in an unbiased manner. To address these challenges, we developed Confidence, a web-based application to perform simultaneous statistical analysis of RNA-seq count data. Confidence incorporates the Confidence Score (CS), ranging from 1 to 4 to aid in gene prioritization, where 1 represents low confidence and 4 represents high confidence. The Confidence web-based application was designed for rapid and intuitive analysis of standard experimental metadata and gene count inputs. Confidence provided a web-based, ‘wide-net’ approach to differential gene expression analysis. Gene scoring allows for unbiased gene selection and identification of novel genes strongly associated with disease and treatment models across multiple species. Additionally, pathway analysis tools have been integrated so that highly confident genes can be placed into biological context in terms of functions and pathways. Confidence provides a new strategy for target prioritization in RNA-seq analysis and the generation of publication-quality figures.

Epigenetic changes in gene expression due to DNA methylation regulate pulmonary vascular structure and function. Genetic or acquired alterations in DNA methylation/demethylation can promote the development of pulmonary arterial hypertension (PAH). Here, we performed epigenome‐wide mapping of DNA methylation in whole blood from 10 healthy people and 19 age/sex‐matched PAH patients from the PAH Biobank. Exome sequencing confirmed the absence of known mutations in PAH‐associated gene variants identifying subjects with or without mutations of TET2, a putative PAH gene encoding the demethylating enzyme, TET2. DNA of patients with PAH and no TET2 mutation was hypermethylated compared to healthy controls. Patients with PAH and a TET2 mutation had greater DNA CpG methylation than mutation‐free PAH patients. Unique Differentially Methylated Regions (DMR) were more common in patients with PAH with TET2 mutations (1164) than in PAH without mutations (262). We correlated methylome findings with a public PAH transcriptomic RNA dataset, prioritizing targets that are both hypermethylated in our cohort and downregulated at the RNA level. Relative to controls, functional analysis reveals enriched functions related to T cell differentiation in PAH patients with a TET2 mutation. We identified genes with downregulated expression that were hypermethylated in PAH patients (with or without a TET2 mutation). In both cases, a conserved T cell phenotype emerged. Pan‐chromosomal hypermethylation in PAH is greatest in patients with TET2 mutations. Observed hypermethylation of genes involved in the pathogenesis of PAH, such as EIF2AK4, and transcription factors that regulate T cell development, such as TCF7, merit further study and may contribute to the inflammation in PAH.

Background: Hypertension is a polygenic, complex disease that impacts men and women differently; whilst the incidence of high blood pressure (BP) is roughly equal over a lifetime, men typically are at higher risk of developing the disease earlier in life, before 50 years of age. There is adequate evidence that the brain is critical for the BP setpoint. The paraventricular nucleus (PVN) of the hypothalamus is an integrative structure that can influence not only neurohumoral responses to blood pressure changes, but also sympathetic drive. Here we manipulate the androgenic status of both male and female spontaneously hypertensive rats (SHRs) to determine how this changes gene expression within the PVN of these animals. Methods: SHR (8-weeks old) were either sham-operated or orchiectomized, whereas all females were oophorectomized, half of which received 10mg testosterone propionate subcutaneously. Mean arterial pressure (MAP) and testosterone (T) were measured by carotid cannulation and ELISA respectively. Sequencing was performed on hand-punched PVN sections and subjected to robust bioinformatic analysis. Results: In total, 6,571 differentially regulated genes (DRGs) are regulated in the PVN of male and female rats. High T (endogenous or replaced) correlates with higher MAP in both sexes. Orchidectomy-induced T depletion resulted in the significant regulation of 5,104 genes, involved in thousands of biological roles, including ones related to hormone and sex-hormone signalling. In the female SHR, testosterone replacement in oophorectomized animals induced the regulation of 1,727 genes, sharing many biological functions with those in the high T males. We validated key genes by qPCR to determine false discovery rate. Conclusions: T status in hypertensive rats correlates with MAP, and consistent changes in PVN transcriptome