Biology subjects

Verhaar, M. C.

Publications and source records attributed to Verhaar, M. C..

6 recordsLinked to original sources

bioRxiv2025

A Novel Human Distal Tubuloid-On-A-Chip Model For Investigating Sodium And Water Transport Mechanisms

The distal segments of the nephron play a central role in regulating water and electrolyte balance, making them critical targets for therapeutic interventions. Damage to these segments is associated with significant health consequences. Studying their (patho)physiology in vivo remains challenging due to the kidneys complex architecture. Recent advances led to the development of more representative in vitro models, including human tubuloids that replicate the phenotype of distal tubule segments. Additionally, novel high throughput microfluidic systems, which support 3D cell culture under flow conditions, provide a platform for closely mimicking in vivo environments. This study presents an enhanced in vitro model of human distal tubule segments by integrating tubuloid culture with the OrganoPlate(R) platform. Tubuloid cells were grown as three-dimensional tubules against a collagen-1 matrix and under alternating flow condition, then differentiated into a distal phenotype. qPCR analysis demonstrated enhanced expression of distal segment markers in 3D flow cultures compared to traditional 2D models. Immunohistochemistry confirmed the formation of a leak-tight, highly polarized epithelium with apical and basolateral localization of key electrolyte transporters. Functional integrity was verified by restricted dextran diffusion and increased transepithelial resistance. Radiolabeled sodium assays revealed active and selective sodium transport mediated by apical epithelial sodium channels (ENaC) and basolateral Na/K ATPase. Sodium transport was followed by water movement, evidenced by dome formation beneath the epithelial monolayer. The models utility was further demonstrated in toxicity studies using trimethoprim, an antibiotic that inhibits ENaC function, resulting in reduced sodium transport and dome formation. This system enables the study of primary human tubule cells with a distal phenotype under controlled flow conditions, allowing direct assessment of water and salt transport. The model provides a valuable tool for investigating distal nephron (patho)physiology and facilitates high-throughput drug development and toxicity testing.

bioengineering↗

bioRxiv2023

The Effect of Mechanical Stimuli on the Phenotypic Plasticity of Induced Pluripotent Stem Cell-Derived Vascular Smooth Muscle Cells in a 3D Hydrogel

IntroductionVascular smooth muscle cells (VSMCs) play a pivotal role in vascular homeostasis, with dysregulation leading to vascular complications. Human induced pluripotent stem cell (hiPSC)-derived VSMCs offer prospects for personalized disease modeling and regenerative strategies. Current research lacks comparative studies on the impact of 3D substrate properties under cyclic strain on phenotype adaptation in hiPSC-derived VSMCs. Here we investigated the potential of human mural cells derived from hiPSC-derived organoids (ODMCs) to undergo phenotypical adaptation under various biological and 3D mechanical stimuli. Methods and resultsODMCs were cultured in 2D conditions with synthetic or contractile differentiation medium, or 3D Gelatin Methacryloyl (GelMa) substrates with varying degrees of functionalization and percentages to modulate material stiffness, elasticity, and crosslink density. Cells in 3D substrates were exposed to cyclic unidirectional strain. Phenotype characterization was conducted using specific markers through immunofluorescence and gene expression analysis. Under static 2D culture, ODMCs derived from hiPSCs exhibited a VSMC phenotype, expressing key mural markers, and demonstrated a level of phenotypic plasticity like primary human vSMCs. In static 3D culture, higher substrate stiffness, lower elasticity and higher crosslink density promoted a contractile phenotype in ODMCs and vSMCs. Dynamic stimulation in 3D substrate promoted a switch towards a contractile phenotype in both cell types. ConclusionOur study demonstrates a phenotypic plasticity of human ODMCs in response to 2D biological and 3D mechanical stimuli that equals that of primary human vSMCs. These findings may contribute to the advancement of tailored approaches for vascular disease modelling and regenerative strategies

cell biology↗

bioRxiv2023

A complex three-dimensional microfluidic model that mimics the early stage events in the human atherosclerotic artery

BackgroundAtherosclerosis is a complex inflammatory vascular disease characterized by lipid and immune cells accumulation in the vessel wall, leading to lumen narrowing. Although several 3D in vitro microfluidic systems were previously described, a realistic reconstruction of the in vivo human atherosclerotic environment requires co-culture of different cell types arranged in atherosclerotic vessel-like structures with exposure to flow and circulating cells, creating challenges for disease modelling. In this study we developed a 3D tubular microfluidic model with quadruple coculture of human aortic smooth muscle cells (hAoSMCs), human umbilical cord vein endothelial cells (HUVECs) and foam cells to re-create a complex human atherosclerotic vessel in vitro to study the effect of flow and circulating immune cells. Methods & ResultsOur new co-culture protocol with BFP-labelled hAoSMCs, GFP-labelled HUVECs and THP-1 macrophages-derived, Dil-labelled Oxidized Low-Density Lipoprotein (Dil-Ox-LDL) foam cells in a fibrinogen-collagen-I based 3D extracellular matrix (ECM) resulted in vessels with an early lesion morphology, showing a layered vessel-like composition with an endothelium and media, with foam cells accumulating in the sub-endothelial space. Perfusion for 24 hours of atherosclerotic and "healthy" vessels (BFP hAoSMCs and GFP HUVECs without foam cells) showed that the layered wall composition remained stable. Perfusion with circulating THP-1 monocytes demonstrated cell extravasation into the atherosclerotic vessel wall and recruitment of THP-1 cells to the foam cell core. QPCR analysis revealed increased expression of atherosclerosis markers in the atherosclerotic vessels and adaptation in VSMCs migration to flow and the plaque microenvironment, compared to control vessels. ConclusionWe present a 3D tubular microfluidic model of a complex early atherosclerotic human vessel that can be exposed to flow and circulating THP-1 monocytes to study hemodynamic changes and immune cell recruitment under live confocal imaging. This novel atherosclerosis-on-a-chip model offers a humanized platform for in-depth mechanistic in vitro studies and drug testing.

cell biology↗

bioRxiv2022

Differentiated kidney tubular cell-derived extracellular vesicles enhance maturation of tubuloids

Advanced kidney in vitro models such as organoids or tubuloids still lack the intrinsic expression of various transport proteins needed for active secretory function. Extracellular vesicles (EVs), cell-derived structures that constitute the organs microenvironment, are known to regulate various cellular processes, including kidney development and regeneration across the nephron. In this study, we propose a new application of renal tubular epithelial cell EVs as modulators for tubuloid functional maturation by increasing the levels of various differentiation markers such as organic anion transport 1 (OAT1), a protein involved in endogenous waste excretion. First, we show that EVs from engineered proximal tubule cells increased the expression of several transcription factors and epithelial transporters in tubuloids that resulted in improved cellular transport capacity. Next, a more in-depth proteomic data analysis demonstrated that EVs can trigger various biological pathways, including mesenchymal-to-epithelial transition, which is crucial in the tubular epithelial maturation process. Moreover, we demonstrated that EV-treated tubuloid-derived cells in a 3D tubular conformation as part of a bioartificial kidney can generate a tight polarized epithelial monolayer with formation of dense cilia structures. In conclusion, EVs from renal tubular epithelial cells can phenotypically improve tubuloid maturation, thereby enhancing their potential as preclinical models and functional units in regenerative therapies.

cell biology↗

bioRxiv2020

Transcriptional regulation profiling reveals disrupted lipid metabolism in failing hearts with a pathogenic phospholamban mutation

BackgroundThe R14del mutation in the phospholamban (PLN) gene is associated with various types of cardiomyopathies and increases the risk of developing life-threatening ventricular arrhythmias. In this study, we focused on a homogeneous Dutch founder cohort of genetic cardiomyopathy due to PLN R14del mutation and aimed to study the influence of epigenetic changes from a multi-dimensional perspective. ResultsUsing cardiac tissue of PLN R14del patients and donors, we identified differentially acetylated promoters and enhancers (H3K27ac ChIPseq), annotated enriched transcription factor (TF) binding motifs located in those regions, and identified differentially expressed genes (RNA-seq). In line with the fibrofatty replacement in PLN R14del hearts at the histological level, our integrative analysis detected the downregulation of key TF regulators in fatty acid oxidation (FAO) metabolisms and their downstream target in PLN R14del hearts as compared to controls. We further examined heart tissue using immunofluorescence staining (IF) and to confirm the mitochondrial lipid abnormalities in the PLN R14del hearts. Furthermore, we observed the accumulation and deformation of lipid droplets and a disrupted morphology of mitochondria, the key organelle where FAO takes place, in PLN R14del heart using transmission electron microscopy (TEM). ConclusionUsing multi-omics approaches, we successfully obtained a unique list of chromatin regions and genes, including TF-coding genes, which played important roles in the metabolism-related signalling in PLN R14del hearts.

genomics↗

bioRxiv2020

Cysteamine-bicalutamide combination treatment restores alpha-ketoglutarate and corrects proximal tubule phenotype in cystinosis

Nephropathic cystinosis is a severe monogenetic kidney disorder caused by mutations in CTNS, encoding the lysosomal transporter cystinosin, resulting in lysosomal cystine accumulation. The sole treatment, cysteamine, slows down the disease progression, but does not correct the established proximal tubulopathy. Here, we developed a new therapeutic strategy by applying an omics-based strategy to expand our knowledge on the complexity of the disease and prioritize drug targets in cystinosis. We identified alpha-ketoglutarate as a key metabolite linking cystinosin loss, lysosomal autophagy defect and proximal tubular impairment in cystinosis. This insight offered a bicalutamide-cysteamine combination treatment as a novel dual target pharmacological approach for the phenotypical correction of cystinotic proximal tubule cells, patient-derived kidney tubuloids and cystinotic zebrafish.

pharmacology and toxicology↗