Biology subjects

de Waard, V.

Publications and source records attributed to de Waard, V..

4 recordsLinked to original sources

bioRxiv2026

Marfan Patient iPSC-Derived Endothelial Cells Carrying FBN1 Variants Reveal Endothelial Dysfunction

Marfan syndrome (MFS) is an inherited connective tissue disorder caused by pathogenic variants in FBN1, encoding fibrillin-1, with life-threatening aortic complications arising in part from endothelial cell (EC) dysfunction. To study this in a human model, we generated hiPSC-derived ECs from three MFS patients (iMFS-ECs). We show that iMFS-ECs recapitulate known disease phenotypes, including impaired alignment in the direction of flow. Moreover, we found that iMFS-ECs do not recover from TNF--induced loss of barrier integrity, due to sustained EC contractility. iMFS-ECs exhibited TNF--induced ICAM1 upregulation and NF-{kappa}B activation comparable to healthy donor-derived hiPSC-ECs by bulk RNA-seq, while expression of genes linked to cytoskeletal arrangements, cell signaling and ECM remodeling were dysregulated. In conclusion, we show that hiPSC derived ECs can serve as a model to investigate MFS pathology. These findings establish a human iPSC platform for MFS endothelial research and suggest impaired inflammatory resolution as a novel therapeutic target.

cell biology↗

bioRxiv2023

Microfibril-associated glycoprotein 4 forms octamers that mediate interactions with elastogenic proteins and cells

Microfibrillar-associated protein 4 (MFAP4) is a 36-kDa extracellular glycoprotein with critical roles in human pathologies, including fibrosis in several organ systems, chronic obstructive pulmonary disease, and cardiovascular disorders. In elastic tissues such as arteries, lungs, and skin, MFAP4 associates with microfibrils and elastic fibres, which are the central extracellular fibres affected in thoracic aneurysms. MFAP4 directly interacts with elastogenic proteins, including fibrillin-1 and tropoelastin, and with cells via integrins. MFAP4 multimerisation represents a critical hallmark required for its physiological and pathological properties. However, molecular details and functional consequences of MFAP4 multimerisation are lacking. Here we present a cryo-electron microscopy structure of human MFAP4. In the presence of calcium, MFAP4 assembles as an octamer with D2 point group symmetry, where two sets of homodimers constitute the top and bottom halves of each octamer. Each of the homodimers is linked together by an inter-molecular disulfide bond. An engineered C34S missense mutation in MFAP4 prevented disulfide-bond formation between monomers, but the mutant formed octamers similar to wild type MFAP4. The atomic model, built into the 3.55 [A] cryo-EM map, suggests that several salt-bridges are important for interactions within and between homodimers, while non-polar interactions are important for octamer halves to assemble. In the absence of calcium, MFAP4 dissociates into tetramers, representing the top/bottom halves of the octamers. Binding studies with elastogenic proteins, including fibrillin-1, tropoelastin, LTBP4, and small fibulins showed that MFAP4 has multiple surfaces for protein-protein interactions, which depend upon the higher-order assembly of MFAP4. While the disulfide-bond mediated by C34S contributes little to those protein interactions, it modulated cell interaction. When MFAP4 forms assemblies with fibrillin-1, it abrogates MFAP4 interactions with cells. Overall, the study provides detailed molecular structure-function relationships of MFAP4 interactions with elastogenic proteins and cells.

cell biology↗

bioRxiv2022

Inhibition of myeloperoxidase prevents thoracic aortic aneurysm formation in Marfan mice

Marfan syndrome (MFS) is the most prevalent inherited connective tissue disorder, still remains uncurable, and is characterized by high mortality at early age driven by dissection and rupture of thoracic aortic aneurysms. MFS is caused by mutations in the fibrillin-1 gene and aberrant TGF{beta} signaling. Here we addressed whether myeloperoxidase (MPO), a leukocyte derived enzyme with potent matrix modulating properties also influences the aortic phenotype in MFS. MFS patients displayed increased circulating MPO levels compared to controls as well as marked aortic MPO deposition. In an MFS mouse model, MPO induced inflammatory endothelial activation and endothelial to mesenchymal transition which triggered aortic leukocyte recruitment. Moreover, MPO directly contributed to adverse extracellular matrix remodeling by promoting oxidative stress and nitration of proteins within the vascular wall. Genetic MPO deficiency and pharmacological MPO inhibition attenuated MFS-related aneurysm formation. We herein identify MPO as a critical mediator of MFS-related thoracic aortic aneurysm formation and - in the absence of any pharmacological treatment so far in this disease - a first anti-inflammatory target to modulate disease progression.

immunology↗

bioRxiv2019

DLC1 is a direct target of activated YAP/TAZ that drives collective migration and sprouting angiogenesis

YAP/TAZ signaling is crucial for sprouting angiogenesis and vascular homeostasis through the regulation of endothelial remodeling. Thus far the underlying molecular mechanisms that explain how YAP/TAZ control the vasculature remain unclear. We here identify Deleted-in-Liver-Cancer-1 (DLC1) as a direct transcriptional target of the activated YAP/TAZ-TEAD complex in the endothelium. Substrate stiffening and VEGF stimuli promote the endothelial expression of DLC1. DLC1 expression is dependent on the presence of YAP and TAZ, and constitutive activation of YAP efficiently promotes expression of DLC1. We show that DLC1 limits F-actin fiber formation, integrin-based focal adhesion lifetime and integrin-mediated traction forces. Depletion of endothelial DLC1 strongly perturbs cell polarization in directed collective migration and inhibits the formation of angiogenic sprouts. Importantly, the inability of YAP-depleted endothelial cells to collectively migrate and form angiogenic sprouts can be rescued by ectopic expression of DLC1. Together, these findings reveal that DLC1 fills a hitherto missing link between YAP/TAZ signaling and endothelial dynamics during angiogenesis.

cell biology↗