Biology subjects

Houweling, A. C.

Publications and source records attributed to Houweling, A. C..

3 recordsLinked to original sources

bioRxiv2024

Role of Forkhead box F1 in the Pathobiology of Pulmonary Arterial Hypertension

RationaleApproximately 80% of patients with non-familial pulmonary arterial hypertension (PAH) lack identifiable pathogenic genetic variants. While most genetic studies of PAH have focused on predicted loss-of-function variants, recent approaches have identified ultra-rare missense variants associated with the disease. FOXF1 encodes a highly conserved transcription factor, essential for angiogenesis and vasculogenesis in human and mouse lungs. ObjectivesWe identified a rare FOXF1 missense coding variant in two unrelated probands with PAH. FOXF1 is an evolutionarily conserved transcription factor required for lung vascular development and vascular integrity. Our aims were to determine the frequency of FOXF1 variants in larger PAH cohorts compared to the general population, study FOXF1 expression in explanted lung tissue from PAH patients versus control (failed-donor) lungs, and define potential downstream targets linked to PAH development. MethodsThree independent, international, multicenter cohorts were analyzed to evaluate the frequency of FOXF1 rare variants. Various composite prediction models assessed the deleteriousness of individual variants. Bulk RNA sequencing datasets from human explanted lung tissues were compared to failed-donor controls to determine FOXF1 expression. Bioinformatic tools identified putative FOXF1 binding targets, which were orthogonally validated using mouse ChIP-seq datasets. Measurements and Main ResultsSeven novel or ultra-rare missense coding variants were identified across three patient cohorts in different regions of the FOXF1 gene, including the DNA binding domain. FOXF1 expression was dysregulated in PAH lungs, correlating with disease severity. Histological analysis showed heterogeneous FOXF1 expression, with the lowest levels in phenotypically abnormal endothelial cells within complex vascular lesions in PAH samples. A hybrid bioinformatic approach identified FOXF1 downstream targets potentially involved in PAH pathogenesis, including BMPR2. ConclusionsLarge genomic and transcriptomic datasets suggest that decreased FOXF1 expression or predicted dysfunction is associated with PAH.

genomics↗

bioRxiv2022

Evaluation of folliculin detection by immunohistochemistry in Birt-Hogg-Dube associated kidney tumors

Germline inactivating mutations in folliculin (FLCN) cause Birt-Hogg-Dube (BHD) syndrome, a rare autosomal dominant disorder predisposing to kidney tumors. Kidney tumors associated with BHD typically lack FLCN expression due to loss of heterozygosity. In this study we assessed the potential of four commercial anti-FLCN antibodies for immunohistochemistry, as currently no routine diagnostic FLCN stainings are performed in the clinic. Despite comprehensive testing, we could not identify a commercial anti-FLCN antibody that is reproducibly effective in immunohistochemical analyses of formalin-fixed paraffin-embedded tissue material. We propose that dedicated future efforts are required to develop a suitable antibody for diagnostic immunohistochemical stainings. The inclusion of FLCN expression status as part of standard renal tumor pathology may contribute to better analyses of the molecular pathology of BHD tumors and facilitate identification of BHD patients, improve their (genetic and clinical) counseling, and enable genetic testing of at risk relatives.

genetics↗

bioRxiv2017

Novel causative genes for heritable pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare disorder with a poor prognosis. Deleterious variation within components of the transforming growth factor-{beta} pathway, particularly the bone morphogenetic protein type 2 receptor (BMPR2), underlie most heritable forms of PAH. Since the missing heritability likely involves genetic variation confined to small numbers of cases, we performed whole genome sequencing in 1038 PAH index cases and 6385 PAH-negative control subjects. Case-control analyses revealed significant overrepresentation of rare variants in novel genes, namely ATP13A3, AQP1 and SOX17, and provided independent validation of a critical role for GDF2 in PAH. We provide evidence for familial segregation of mutations in SOX17 and AQP1 with PAH. Mutations in GDF2, encoding a BMPR2 ligand, led to reduced secretion from transfected cells. In addition, we identified pathogenic mutations in the majority of previously reported PAH genes, and provide evidence for further putative genes. Taken together these findings provide new insights into the molecular basis of PAH and indicate unexplored pathways for therapeutic intervention.

genetics↗