Biology subjects

van Meer, B. J.

Publications and source records attributed to van Meer, B. J..

4 recordsLinked to original sources

bioRxiv2025

A simplified co-culture reveals altered cardiotoxic responses to doxorubicin in hPSC-derived cardiomyocytes in the presence of endothelial cells

Cardiotoxicity is a significant challenge in cancer therapies, particularly with doxorubicin, a widely used anthracycline known for its broad anti-cancer spectrum but life-threatening cardiac side effects. There is a critical need for more predictive in vitro models to understand doxorubicin-induced cardiotoxicity and patient-specific drug responses. In this study, we used human pluripotent stem cell (hPSC)-derived cardiomyocytes (hPSC-CMs), cardiac fibroblasts (hPSC-cFBs) and endothelial cells (hPSC-ECs) to investigate the cardiotoxic effects of doxorubicin in two-dimensional mono-and multi-cell type cultures. By mimicking the cumulative dose effect seen in patients through repeated doxorubicin treatments and using a machine learning-based in silico image analysis tool, we could precisely quantify caspase 3/7 activity as an early toxicity marker and identify hPSC-CMs in multi-cell type cultures. This innovative approach allowed continuous monitoring of apoptosis from phase-contrast images, revealing that hPSC-ECs showed higher sensitivity to doxorubicin than isogenic hPSC-CMs or hPSC-cFBs and significantly enhanced cardiomyocyte toxicity in co-culture. In contrast, dermal fibroblasts differentiated from the same hPSC line showed no toxic response under the same treatment regimen. These results challenge the conventional focus on cardiomyocytes as the target of drug-induced cardiac damage. Our findings not only highlight the complex interplay among different cardiac cell types in mediating the toxic effects of doxorubicin, but also demonstrate the potential of AI-enabled tools to advance personalized drug screening and safety assessments.

pharmacology and toxicology↗

bioRxiv2021

STRAIGHT-IN: A platform for high-throughput targeting of large DNA payloads into human pluripotent stem cells

Inserting large DNA payloads (>10 kb) into specific genomic sites of mammalian cells remains challenging. Applications ranging from synthetic biology to evaluating the pathogenicity of disease-associated variants for precision medicine initiatives would greatly benefit from tools that facilitate this process. Here, we merge the strengths of different classes of site-specific recombinases and combine these with CRISPR/Cas9-mediated homologous recombination to develop a strategy for stringent site-specific replacement of genomic fragments at least 50 kb in size in human induced pluripotent stem cells (hiPSCs). We demonstrate the versatility of STRAIGHT-IN (Serine and Tyrosine Recombinase Assisted Integration of Genes for High-Throughput INvestigation) by: (i) inserting various combinations of fluorescent reporters into hiPSCs to assess excitation-contraction coupling cascade in derivative cardiomyocytes, and; (ii) simultaneously targeting multiple variants associated with inherited cardiac arrhythmic disorder into a pool of hiPSCs. STRAIGHT-IN offers a precise approach to generate genetically-matched panels of hiPSC lines efficiently and cost-effectively.

cell biology↗

bioRxiv2019

Isogenic sets of hiPSC-CMs harboring KCNH2 mutations capture location-related phenotypic differences

AimsLong QT syndrome type 2 (LQT2) is caused by mutations in the gene KCNH2, encoding the hERG ion channel. Clinically, mild and severe phenotypes are associated with this cardiac channelopathy, complicating efforts to predict patient risk. The location of the mutation within KCNH2 contributes to this variable disease manifestation. Here we determined whether such phenotypic differences could be detected in cardiomyocytes derived from isogenic human induced pluripotent stem cells (hiPSCs) genetically edited to harbour a range of KCNH2 mutations. Methods and ResultsThe hiPSC lines heterozygous for missense mutations either within the pore or tail region of the ion channel were generated using CRISPR-Cas9 editing and subsequently differentiated to cardiomyocytes (hiPSC-CMs) for functional assessment. Electrophysiological analysis confirmed the mutations prolonged the action potentials and field potentials of the hiPSC-CMs, with differences detected between the pore and tail region mutations when measured as paced 2D monolayers. This was also reflected in the cytosolic Ca2+ transients and contraction kinetics of the different lines. Pharmacological blocking of the hERG channel in the hiPSC-CMs also revealed that mutations in the pore-loop region conferred a greater susceptibility to arrhythmic events. ConclusionThese findings establish that subtle phenotypic differences related to the location of the KCNH2 mutation in LQT2 patients are reflected in hiPSC-CMs under genetically controlled conditions. Moreover, the results validate hiPSC-CMs as a strong candidate for evaluating the underlying severity of individual KCNH2 mutations in humans which could ultimately facilitate patient risk stratification. Translational perspectiveClinical management of patients diagnosed with cardiac channelopathy diseases such as LQT2 is complicated by the variable disease phenotypes observed among mutation carriers, creating challenges for diagnosis, risk stratification and treatment. The genotype of the patient contributes to this clinical heterogeneity, with the influence of the mutations location within KCNH2 on a patients risk of a cardiac event being an example. Here we demonstrate that under stringently controlled genetic and experimental conditions, hiPSC-CMs are able to reflect these subtle genotype-phenotype differences, thereby providing new opportunities to stratify and potentially lessen sudden cardiac death risk amongst KCNH2 mutation carriers.

cell biology↗

bioRxiv2017

Versatile open software to quantify cardiomyocyte and cardiac muscle contraction in vitro and in vivo

Contraction of muscle reflects its physiological state. Methods to quantify contraction are often complex, expensive and tailored to specific models or recording conditions, or require specialist knowledge for data extraction. Here we describe an automated, open-source software tool (MUSCLEMOTION) adaptable for use with standard laboratory and clinical imaging equipment that enables quantitative analysis of normal cardiac contraction, disease phenotypes and pharmacological responses. MUSCLEMOTION allowed rapid and easy measurement of contractility in (i) single cardiomyocytes from primary adult heart and human pluripotent stem cells, (ii) multicellular 2D-cardiomyocyte cultures, 3D engineered heart tissues and cardiac organoids/microtissues in vitro and (iii) intact hearts of zebrafish and humans in vivo. Good correlation was found with conventional measures of contraction in each system. Thus, using a single method for processing video recordings, we obtained reliable pharmacological data and measures of cardiac disease phenotype in experimental cell- and animal models and human echocardiograms.

physiology↗