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Biology subjects

Karperien, M.

Publications and source records attributed to Karperien, M..

3 recordsLinked to original sources

A human engineered mini-heart platform for mimicking ventricular pump function

Engineered cardiac tissue models for in vitro physiological studies often fail to replicate the pump function of the heart. Despite promising advancements, the use of engineered cardiac chambers is often hindered by complex fabrication processes and invasive characterization techniques. Here, we engineered a human cardiac chamber, referred to as a mini-heart, by employing a novel sacrificial molding approach within a customized bioreactor. The mini-hearts pumping capability was confirmed through optical recording of fluid displacement at the engineered tissue inlet, enabling the non-invasive acquisition of hemodynamic parameters such as stroke volume, stroke work, ejection fraction, and developed pressure. Morphological analysis of the engineered tissues revealed organized sarcomeres and extracellular matrix self-determination, highlighting the advantage of our degradable mold technology. Additionally, we have measured calcium transients during both spontaneous and electrically-paced beating, and observed a positive inotropic response to the {beta}-adrenergic agonist drug isoproterenol. Altogether, our biomimicking engineered tissue platform provides a robust tool for exploring cardiac pressure-volume dynamics, thereby facilitating complex disease modelling and drug screening applications in vitro.

bioengineering↗

Mapping RUNX2 transcriptional dynamics during multi-lineage differentiation of human mesenchymal stem cells

The multi-lineage differentiation capacity of human mesenchymal stem cells (hMSCs) enables its potential for tissue engineering and regenerative medicine. Master transcription factors play a key role during development, differentiation, homeostasis and disease pathology. RUNX2 is the master transcription factor for bone development, and it regulates several important signaling pathways during chondrogenic and osteogenic differentiation of hMSCs. However, modulation of RUNX2 activity during hMSC differentiation into various lineages is not yet fully described. We differentiated hMSCs into chondro-, osteo-, and adipogenic lineages and studied RUNX2 protein dynamics using Transcription Factor - Fluorescence Recovery After Photobleaching (TF-FRAP) at different time points. The TF-FRAP method can capture the dynamic changes of RUNX2 protein mobility at the single cell level resolution, and cluster analysis shows how RUNX2 dynamics change at subpopulation level in proliferating and differentiating hMSCs. Our data show that although whole hMSC population is exposed to differentiation stimuli, some subpopulations in hMSCs do not respond to environmental cues.

cell biology↗

Mapping SOX9 transcriptional dynamics during multi-lineage differentiation of human mesenchymal stem cells

The master transcription factor SOX9 is a key player during chondrocyte differentiation, cartilage development, homeostasis and disease. Modulation of SOX9 and its target gene expression is essential during chondrogenic, osteogenic and adipogenic differentiation of human mesenchymal stem cells (hMSCs). However, lack of sufficient knowledge about the signaling interplay during differentiation remains one of the main reasons preventing successful application of hMSCs in regenerative medicine. We previously showed that Transcription Factor - Fluorescence Recovery After Photobleaching (TF-FRAP) can be used to study SOX9 dynamics at the single cell level. We showed that changes in SOX9 dynamics are linked to its transcriptional activity. Here, we investigated SOX9 dynamics during differentiation of hMSCs into the chondrogenic, osteogenic and adipogenic lineages. We show that there are clusters of cells in hMSCs with distinct SOX9 dynamics, indicating that there are a number of subpopulations present in the heterogeneous hMSCs. SOX9 dynamics data at the single cell resolution revealed novel insights about its activity in these subpopulations (cell types). In addition, the response of SOX9 to differentiation stimuli varied in these subpopulations. Moreover, we identified donor specific differences in the number of cells per cluster in undifferentiated hMSCs, and this correlated to their differentiation potential.

molecular biology↗