Biology subjects

Janssen, M.

Publications and source records attributed to Janssen, M..

7 recordsLinked to original sources

bioRxiv2026

Dynamic suspension culture enhances scalable maturation of hiPSC-derived cartilage organoids for regenerative medicine

BackgroundCartilage tissue engineering requires scalable culture strategies to produce high-quality organoids. Human induced pluripotent stem cells (hiPSCs) provide a renewable source of chondrogenic cells. However, conventional static 3D culture limits tissue maturation, reproducibility, and scalability. Dynamic culture systems may help overcome these limitations, although their application for hiPSC-derived cartilage maturation remains poorly explored. MethodsIn this study, we established and validated a dynamic suspension bioreactor culture platform (CERO, OLS) for scalable maturation of hiPSC-derived chondroprogenitor cells (hiCPCs) into cartilage organoids populated by biomimetic human induced chondrocytes (hiCHOs). Key culture parameters, including aggregate preparation strategy, agitation speed, and maturation duration, were systematically evaluated. Cartilage maturation under dynamic and conventional static culture conditions was assessed by histology and immunohistochemistry, biochemical assays, organoid size measurements, and gene expression (RT-qPCR). In addition, the functional integration of optimized organoids was evaluated in a human osteochondral explant model. ResultsPre-formed manually picked hiCPC aggregates showed improved cartilage formation compared with single-cell seeding or pelleted aggregates in the bioreactor. Dynamic suspension culture promoted increased construct growth, enhanced ECM deposition, and a more favourable cartilage-associated molecular phenotype compared with static culture. HiCHO organoids matured under dynamic suspension conditions displayed increased sulphated glycosaminoglycan and proteoglycan deposition together with higher expression of cartilage-associated genes ACAN, COMP, MGP, and COL2A1. Although prolonged static maturation alone supported continued cartilage development, introducing dynamic suspension culture during later maturation stages further reinforced favourable molecular and matrix-associated features. Importantly, hiCHO organoids generated under optimized dynamic culture conditions successfully filled human cartilage defects and established matrix continuity with surrounding native tissue in a human osteochondral ex vivo explant model. ConclusionsThis study shows that dynamic suspension culture is an effective and scalable strategy for maturation of hiPSC-derived cartilage organoids. Consequently, this approach supports reproducible neo-cartilage production and allows functional testing in human tissue models. These findings support the use of dynamic culture systems for cartilage repair and in vitro/ex vivo cartilage research.

Cell Biology↗

bioRxiv2025

Metabolic Signatures of Pulmonary Embolism in COVID-19: Insights from Longitudinal Intensive Care Unit Profiles

ABSTRACTO_ST_ABSBackgroundC_ST_ABSPulmonary embolism is a severe complication of COVID-19 infection, associated with a hypercoagulable state and heightened risk of blood clots. As SARS-CoV-2 has become endemic, understanding pulmonary embolisms metabolic effects in COVID-19 patients is warranted. This study investigated the longitudinal metabolic profiles of 66 Intensive Care Unit-admitted COVID-19 patients at Erasmus Medical Center to identify metabolites and mechanisms associated with pulmonary embolism. MethodA total of 1209 metabolic species were measured, including amines and lipids. Metabolic changes were analysed across four timeframes: i) general analysis of pulmonary embolism, ii) 72 hours prior to pulmonary embolism, iii) 48 hours prior and the day of pulmonary embolism, and iv) the day of and 48 hours post-pulmonary embolism. ResultsThe general analysis revealed significant upregulation of amines, triglycerides, phosphatidylethanolamines, ether-linked phosphatidylethanolamines, and eicosanoids in patients who developed a pulmonary embolism. Phosphatidylethanolamines containing the 20:3 fatty acid side chain were notably elevated. Minimal metabolic dysregulation was observed 72 hours before pulmonary embolism, with subtle increases in lysophosphatidylcholines and lysophosphatidylethanolamines. In contrast, there was a strong metabolic response during and post-pulmonary embolism, phosphatidylethanolamines (47%), ether-linked phosphatidylethanolamines(96%) and sphingosines(40%). ConclusionThese findings underscore the critical role of lipid metabolism in pulmonary embolism, particularly triglycerides and specific lipid species. The limited metabolic perturbations before pulmonary embolism suggest early prediction challenges, emphasising the need for further research into temporal metabolic changes and their clinical applications.

molecular biology↗

bioRxiv2023

CTNS mRNA as a potential treatment for nephropathic cystinosis

Messenger RNA (mRNA) therapies are emerging in different disease areas, but have not yet reached the kidney field. Our aim was to study the feasibility to correct the genetic defect in nephropathic cystinosis using synthetic mRNA. Cystinosis is a prototype disorder of proximal tubular dysfunction caused by mutations in the CTNS gene, encoding the lysosomal cystine-H+ symporter cystinosin, and leading to cystine accumulation in all cells of the body. The kidneys are the first and most severely affected organs, presenting glomerular and proximal tubular dysfunction. Cysteamine is the current therapeutic standard that reduces cellular cystine levels, but has many side effects and does not restore kidney function. Here, we show that synthetic mRNA is safe and effective to reintroduce functional cystinosin using lipofection in CTNS-/- kidney cells and following direct injection in ctns-/- zebrafish larvae. CTNS mRNA therapy results in prompt lysosomal expression of the functional protein and decreases cellular cystine accumulation for up to 14 days. In the ctns-/- zebrafish, CTNS mRNA therapy improves proximal tubular reabsorption, reduces proteinuria, and restores brush border expression of the multi-ligand receptor megalin. We propose that mRNA-based therapy, if sufficient kidney targeting can be achieved, may be a new approach to treat cystinosis. Translational statementCystinosis is a systemic lysosomal storage disease caused by mutations in the CTNS (cystinosin) gene. It initially affects the kidneys and leads to kidney failure, if left untreated. The current standard therapy, cysteamine, is not curative and has many side-effects. Here we demonstrate the potential of mRNA-based therapy to swiftly restore cystinosin function and ameliorate the kidney phenotype. Future research will focus on mRNA delivery methods and targeting kidney cells in cystinosis rodent models.

genetics↗

bioRxiv2022

Stability of a biomembrane tube covered with proteins

Membrane tubes are essential structural features in cells that facilitate biomaterial transport and inter- and intracellular signalling. The shape of these tubes can be regulated by the proteins that surround and adhere to them. We study the stability of a biomembrane tube coated with proteins by combining linear stability analysis, out-of-equilibrium hydrodynamic calculations, and numerical solutions of a Helfrich-like membrane model. Our analysis demonstrates that both long and short-wavelength perturbations can destabilise the tubes. Numerical simulations confirm the derived linear stability criteria and yield the nonlinearly-perturbed vesicle shapes. Our study highlights the interplay between membrane shape and protein density, where the shape instability concurs with a redistribution of proteins into a banded pattern.

biophysics↗

bioRxiv2022

Clonally resolved single-cell multi-omics identifies routes of cellular differentiation in acute myeloid leukemia

Inter-patient variability and the similarity of healthy and leukemic stem cells have impeded the characterization of leukemic stem cells (LSCs) in acute myeloid leukemia (AML), and their differentiation landscape. Here, we introduce CloneTracer, a novel method that adds clonal resolution to single-cell RNA-seq datasets. Applied to samples from 19 AML patients, CloneTracer revealed routes of leukemic differentiation. While residual healthy cells dominated the dormant stem cell compartment, active leukemic stem cells resembled their healthy counterpart and retained erythroid capacity. By contrast, downstream myeloid progenitors were highly aberrant and constituted the disease-defining compartment: Their gene expression and differentiation state determined both chemotherapy response and the leukemias ability to differentiate to transcriptomically normal monocytes. Finally, we demonstrated the potential of CloneTracer to identify surface markers mis-regulated specifically in leukemic cells by intra-patient comparisons. Taken together, CloneTracer revealed a differentiation landscape that mimics its healthy counterpart and determines biology and therapy response in AML.

cancer biology↗

bioRxiv2020

The effect of noise trauma and high-frequency stimulation on thalamic sensory gating in rodents

BackgroundThe medial geniculate body (MGB) of the thalamus plays a central role in tinnitus pathophysiology. Breakdown of sensory gating in this part of the auditory thalamus is a potential mechanism underlying tinnitus. The alleviation of tinnitus-like behavior by high-frequency stimulation (HFS) of the MGB might mitigate dysfunctional sensory gating. ObjectiveThe study aims at exploring the role of the MGB in sensory gating as a mandatory relay area in auditory processing in noise-exposed and control subjects, and to assess the effect of MGB HFS on this function. MethodsNoise-exposed rats and controls were tested. Continuous auditory sequences were presented to allow assessment of sensory gating effects associated with pitch, binary grouping, and temporal regularity. Evoked potentials (EP) were recorded from the MGB and acquired before and after HFS (100 Hz). ResultsNoise-exposed rats showed differential modulation of MGB EP amplitudes, confirmed by significant main effects of stimulus type, pair position and temporal regularity. Noise-exposure selectively abolished the effect of temporal regularity on EP amplitudes. A significant three-way interaction between HFS phase, temporal regularity and rat condition (noise-exposed, control) revealed that only noise-exposed rats showed significantly reduced EP amplitudes following MGB HFS. ConclusionThis is the first report that shows thalamic filtering of incoming auditory signals based on different sound features. Noise-exposed rats further showed higher EP amplitudes in most conditions and did not differentiate the temporal regularity. Critically, MGB HFS was effective in reducing amplitudes of the EP responses in noise-exposed animals. HighlightsO_LIEP findings indicate sensory gating in the MGB in rats. C_LIO_LINoise exposure alters EP amplitudes in the MGB. C_LIO_LIHFS selectively suppresses EP responses in noise-exposed animals. C_LI

neuroscience↗

bioRxiv2017

Spontaneous eye blink rate and dopamine synthesis capacity: Preliminary evidence for an absence of positive correlation

Dopamine is central to a number of cognitive functions and brain disorders. Given the cost of neurochemical imaging in humans, behavioral proxy measures of dopamine have gained in popularity in the past decade, such as spontaneous eye blink rate (sEBR). Increased sEBR is commonly associated with increased dopamine function based on pharmacological evidence and patient studies. Yet, this hypothesis has not been validated using in vivo measures of dopamine function in humans. In order to fill this gap, we measured sEBR and striatal dopamine synthesis capacity using [18F]DOPA PET in 20 participants (9 healthy individuals and 11 pathological gamblers). Our results, based on frequentist and Bayesian statistics, as well as region-of-interest and voxel-wise analyses, argue against a positive relationship between sEBR and striatal dopamine synthesis capacity. They show that, if anything, the evidence is in favor of a negative relationship. These results, which complement findings from a recent study that failed to observe a relationship between sEBR and dopamine D2 receptor availability, suggest that caution and nuance are warranted when interpreting sEBR in terms of a proxy measure of striatal dopamine.

neuroscience↗