Justyna Stokowiec

• Martinez, Mikel Amirola; Combriat, Thomas Michel Daniel; Ferencevic, Katharina; Wilhelmsen, Ingrid; Dalmao-Fernandez, Andrea & Olsen, Petter Angell [Show all 9 contributors for this article] (2025). Aspects of zone-like identity and holotomographic tracking of human stem cell-derived liver sinusoidal endothelial cells. Frontiers in Cell and Developmental Biology. 13. doi: 10.3389/fcell.2025.1528991. Full text in Research Archive Show summary

  Introduction: Liver sinusoidal endothelial cells (LSEC) are specialized endothelial cells with unique metabolic and barrier functions adapted to the needs of the liver sinusoid. LSECs are highly sensitive to their environment, and this fragile nature causes challenges in analyzing their phenotype under in vitro conditions. Methods: In this work, we first differentiated LSEC-like cells (scLSECs) from two human pluripotent stem cell lines and characterized them by a panel of qPCR markers, immunohistochemistry, substrate oxidation for energy metabolism, scavenger function, and nitric oxide secretion. We then introduced holotomography, a technique that allows to recover quantitative and three-dimensional information about the refractive indexes of cell components, as a tool to image and track scLSEC in vitro in a minimally intrusive, label-free manner. Results and discussion: Holotomography and developed machine learning-based algorithm for image processing allowed us to describe and monitor changes in intracellular pore-like structures over time. Finally, we tested the possibility of inducing aspects of zone-specific LSEC phenotype and metabolism using culture-based treatments, which resulted in modest shifts in marker expression and metabolic activity. The presented strategy provides an advanced tool kit for investigating liver endothelial cells.

• Delon, Ludivine; Busek, Mathias; Menezes, Pedro Duarte; Gadegaard, Nikolaj; Stokowiec, Justyna & Golovin, Alexey [Show all 10 contributors for this article] (2025). Placental Syncytium-on-Chip (PSoC)–Comparison of Forskolin or Mechanical Induced-Syncytialization. Advanced Healthcare Materials. ISSN 2192-2640. doi: 10.1002/adhm.202404462. Full text in Research Archive Show summary

  The placenta is a key embryonic structure that separates maternal and fetal blood systems. The barrier function of the human placenta is performed by villous trophoblasts, i.e. undifferentiated cytotrophoblasts and differentiated syncytiotrophoblats, whose maturation and function are influenced by wall shear stress (WSS) from the maternal blood circulation. Most in vitro placenta models rely on cyclic adenosine monophosphate inducer forskolin (FSK) to establish a placental syncytium. Here a trophoblastic BeWo cell line is used to systematically compare the effect of FSK treatment in static culture with WSS stimulation in a pumpless, recirculating organ-on-chip. It is shown that BeWo cells undergo a similar differentiation under WSS exposure to FSK treatment. A WSS of 0.1 dyn cm−2 leads to cell fusion, polarization, barrier functions, human chorionic gonadotropin (β-hCG) secretion, and increased expression of key transporters. Moreover, WSS induces favorable changes in the levels of FMS-like tyrosine kinase-1 (FLT-1) and Placental Growth Factor (PlGF) suggesting the development of a physiologically relevant placental syncytium-on-chip (PSoC) without the need for FSK. The platform is further expanded to a syncytiotrophoblast/endothelial co-culture showing physiological vascular functions under WSS. The forskolin-free PSoC presented here represents the first pumpless recirculating and scalable platform for physiological placental studies and drug testing.

• Wilhelmsen, Ingrid; Combriat, Thomas Michel Daniel; Dalmao-Fernandez, Andrea; Stokowiec, Justyna; Wang, Chencheng & Olsen, Petter Angell [Show all 10 contributors for this article] (2024). The effects of TGF-β-induced activation and starvation of vitamin A and palmitic acid on human stem cell-derived hepatic stellate cells. Stem Cell Research & Therapy. 15(223). doi: 10.1186/s13287-024-03852-8. Full text in Research Archive Show summary

  Background Hepatic stellate cells (HSC) have numerous critical roles in liver function and homeostasis, while they are also known for their importance during liver injury and fibrosis. There is therefore a need for relevant in vitro human HSC models to fill current knowledge gaps. In particular, the roles of vitamin A (VA), lipid droplets (LDs), and energy metabolism in human HSC activation are poorly understood. Methods In this study, human pluripotent stem cell-derived HSCs (scHSCs), benchmarked to human primary HSC, were exposed to 48-hour starvation of retinol (ROL) and palmitic acid (PA) in the presence or absence of the potent HSC activator TGF-β. The interventions were studied by an extensive set of phenotypic and functional analyses, including transcriptomic analysis, measurement of activation-related proteins and cytokines, VA- and LD storage, and cell energy metabolism. Results The results show that though the starvation of ROL and PA alone did not induce scHSC activation, the starvation amplified the TGF-β-induced activation-related transcriptome. However, TGF-β-induced activation alone did not lead to a reduction in VA or LD stores. Additionally, reduced glycolysis and increased mitochondrial fission were observed in response to TGF-β. Conclusions scHSCs are robust models for activation studies. The loss of VA and LDs is not sufficient for scHSC activation in vitro, but may amplify the TGF-β-induced activation response. Collectively, our work provides an extensive framework for studying human HSCs in healthy and diseased conditions.

• Aizenshtadt, Aleksandra; Wang, Chencheng; Abadpour, Shadab; Menezes, Pedro Duarte; Wilhelmsen, Ingrid & Dalmao-Fernandez, Andrea [Show all 15 contributors for this article] (2024). Pump-Less, Recirculating Organ-on-Chip (rOoC) Platform to Model the Metabolic Crosstalk between Islets and Liver. Advanced Healthcare Materials. ISSN 2192-2640. 13(13). doi: 10.1002/adhm.202303785. Full text in Research Archive Show summary

  Type 2 diabetes mellitus (T2DM), obesity, and metabolic dysfunction-associated steatotic liver disease (MASLD) are epidemiologically correlated disorders with a worldwide growing prevalence. While the mechanisms leading to the onset and development of these conditions are not fully understood, predictive tissue representations for studying the coordinated interactions between central organs that regulate energy metabolism, particularly the liver and pancreatic islets, are needed. Here, a dual pump-less recirculating organ-on-chip platform that combines human pluripotent stem cell (sc)-derived sc-liver and sc-islet organoids is presented. The platform reproduces key aspects of the metabolic cross-talk between both organs, including glucose levels and selected hormones, and supports the viability and functionality of both sc-islet and sc-liver organoids while preserving a reduced release of pro-inflammatory cytokines. In a model of metabolic disruption in response to treatment with high lipids and fructose, sc-liver organoids exhibit hallmarks of steatosis and insulin resistance, while sc-islets produce pro-inflammatory cytokines on-chip. Finally, the platform reproduces known effects of anti-diabetic drugs on-chip. Taken together, the platform provides a basis for functional studies of obesity, T2DM, and MASLD on-chip, as well as for testing potential therapeutic interventions.

• Wang, Chencheng; Abadpour, Shadab; Aizenshtadt, Aleksandra; Dalmao-Fernandez, Andrea; Høyem, Merete & Wilhelmsen, Ingrid [Show all 13 contributors for this article] (2024). Cell identity dynamics and insight into insulin secretagogues when employing stem cell-derived islets for disease modeling. Frontiers in Bioengineering and Biotechnology. 12. doi: 10.3389/fbioe.2024.1392575. Full text in Research Archive Show summary

  Stem cell-derived islets (SC-islets) are not only an unlimited source for cell-based therapy of type 1 diabetes but have also emerged as an attractive material for modeling diabetes and conducting screening for treatment options. Prior to SC-islets becoming the established standard for disease modeling and drug development, it is essential to understand their response to various nutrient sources in vitro. This study demonstrates an enhanced efficiency of pancreatic endocrine cell differentiation through the incorporation of WNT signaling inhibition following the definitive endoderm stage. We have identified a tri-hormonal cell population within SC-islets, which undergoes reduction concurrent with the emergence of elevated numbers of glucagon-positive cells during extended in vitro culture. Over a 6-week period of in vitro culture, the SC-islets consistently demonstrated robust insulin secretion in response to glucose stimulation. Moreover, they manifested diverse reactivity patterns when exposed to distinct nutrient sources and exhibited deviant glycolytic metabolic characteristics in comparison to human primary islets. Although the SC-islets demonstrated an aberrant glucose metabolism trafficking, the evaluation of a potential antidiabetic drug, pyruvate kinase agonist known as TEPP46, significantly improved in vitro insulin secretion of SC-islets. Overall, this study provided cell identity dynamics investigation of SC-islets during prolonged culturing in vitro, and insights into insulin secretagogues. Associated advantages and limitations were discussed when employing SC-islets for disease modeling.

• Wang, Chencheng; Abadpour, Shadab; Olsen, Petter Angell; Wang, Daxin; Stokowiec, Justyna & Chera, Simona [Show all 11 contributors for this article] (2024). Glucose Concentration in Regulating Induced Pluripotent Stem Cells Differentiation Toward Insulin-Producing Cells. Transplant International. ISSN 0934-0874. 37. doi: 10.3389/ti.2024.11900. Full text in Research Archive Show summary

  The generation of insulin-producing cells from human-induced pluripotent stem cells holds great potential for diabetes modeling and treatment. However, existing protocols typically involve incubating cells with un-physiologically high concentrations of glucose, which often fail to generate fully functional IPCs. Here, we investigated the influence of high (20 mM) versus low (5.5 mM) glucose concentrations on IPCs differentiation in three hiPSC lines. In two hiPSC lines that were unable to differentiate to IPCs sufficiently, we found that high glucose during differentiation leads to a shortage of NKX6.1+ cells that have co-expression with PDX1 due to insufficient NKX6.1 gene activation, thus further reducing differentiation efficiency. Furthermore, high glucose during differentiation weakened mitochondrial respiration ability. In the third iPSC line, which is IPC differentiation amenable, glucose concentrations did not affect the PDX1/NKX6.1 expression and differentiation efficiency. In addition, glucose-stimulated insulin secretion was only seen in the differentiation under a high glucose condition. These IPCs have higher KATP channel activity and were linked to sufficient ABCC8 gene expression under a high glucose condition. These data suggest high glucose concentration during IPC differentiation is necessary to generate functional IPCs. However, in cell lines that were IPC differentiation unamenable, high glucose could worsen the situation.

• LaLone, Vernon; Aizenshtadt, Aleksandra; Goertz, John; Skottvoll, Frøydis Sved; Mota, Marco Barbero & You, Junji [Show all 15 contributors for this article] (2023). Quantitative chemometric phenotyping of three-dimensional liver organoids by Raman spectral imaging. Cell Reports Methods. 3(4). doi: 10.1016/j.crmeth.2023.100440. Full text in Research Archive Show summary

  Confocal Raman spectral imaging (RSI) enables high-content, label-free visualization of a wide range of molecules in biological specimens without sample preparation. However, reliable quantification of the deconvoluted spectra is needed. Here we develop an integrated bioanalytical methodology, qRamanomics, to qualify RSI as a tissue phantom calibrated tool for quantitative spatial chemotyping of major classes of biomolecules. Next, we apply qRamanomics to fixed 3D liver organoids generated from stem-cell-derived or primary hepatocytes to assess specimen variation and maturity. We then demonstrate the utility of qRamanomics for identifying biomolecular response signatures from a panel of liver-altering drugs, probing drug-induced compositional changes in 3D organoids followed by in situ monitoring of drug metabolism and accumulation. Quantitative chemometric phenotyping constitutes an important step in developing quantitative label-free interrogation of 3D biological specimens.

• Busek, Mathias; Aizenshtadt, Aleksandra; Koch, Timo; Frank, Anna; Delon, Ludivine Sylvie Claude & Martinez, Mikel Amirola [Show all 12 contributors for this article] (2023). Pump-less, recirculating organ-on-a-chip (rOoC) platform. Lab on a Chip. ISSN 1473-0197. doi: 10.1039/D2LC00919F. Full text in Research Archive
• Wilhelmsen, Ingrid; Martinez, Mikel Amirola; Stokowiec, Justyna; Wang, Chencheng; Aizenshtadt, Aleksandra & Krauss, Stefan Johannes Karl (2023). Characterization of human stem cell-derived hepatic stellate cells and liver sinusoidal endothelial cells during extended in vitro culture. Frontiers in Bioengineering and Biotechnology. 11. doi: 10.3389/fbioe.2023.1223737. Full text in Research Archive Show summary

  Background: There is a significant need for predictive and stable in vitro human liver representations for disease modeling and drug testing. Hepatic stellate cells (HSCs) and liver sinusoidal endothelial cells (LSECs) are important non-parenchymal cell components of the liver and are hence of relevance in a variety of disease models, including hepatic fibrosis. Pluripotent stem cell- (PSC-) derived HSCs (scHSCs) and LSECs (scLSECs) offer an attractive alternative to primary human material; yet, the suitability of scHSCs and scLSECs for extended in vitro modeling has not been characterized. Methods: In this study, we describe the phenotypic and functional development of scHSCs and scLSECs during 14 days of 2D in vitro culture. Cell-specific phenotypes were evaluated by cell morphology, immunofluorescence, and gene- and protein expression. Functionality was assessed in scHSCs by their capacity for intracellular storage of vitamin A and response to pro-fibrotic stimuli induced by TGF-β. scLSECs were evaluated by nitric oxide- and factor VIII secretion as well as endocytic uptake of bioparticles and acetylated low-density lipoprotein. Notch pathway inhibition and co-culturing scHSCs and scLSECs were separately tested as options for enhancing long-term stability and maturation of the cells. Results and Conclusion: Both scHSCs and scLSECs exhibited a post-differentiation cell type-specific phenotype and functionality but deteriorated during extended culture with PSC line-dependent variability. Therefore, the choice of PSC line and experimental timeframe is crucial when designing in vitro platforms involving scHSCs and scLSECs. Notch inhibition modestly improved long-term monoculture in a cell line-dependent manner, while co-culturing scHSCs and scLSECs provides a strategy to enhance phenotypic and functional stability.

• Busek, Mathias; Aizenshtadt, Aleksandra; Koch, Timo; Frank, Anna; Delon, Ludivine Sylvie Claude & Martinez, Mikel Amirola [Show all 12 contributors for this article] (2022). Pump-less, recirculating organ-on-a-chip (rOoC) platform. Lab on a Chip. ISSN 1473-0197. p. 345–361. doi: 10.1039/d2lc00919f. Full text in Research Archive Show summary

  We developed a novel, pump-less directional flow recirculating organ-on-a-chip (rOoC) platform that creates controlled unidirectional gravity-driven flow by a combination of a 3D-tilting system and an optimized microfluidic layout. The rOoC platform was assembled utilizing a layer-to-layer fabrication technology based on thermoplastic materials. It features two organoid compartments supported by two independent perfusion channels and separated by a hydrogel barrier. We developed a computational model to predict wall shear stress values and then measured the flow rate in the microfluidic channels with micro-Particle-Image-Velocimetry (μPIV). The suitability of the rOoC for functional culture of endothelial cells was tested using HUVECs seeded in the perfusion channels. HUVECs aligned in response to the directional flow, formed a barrier and were able to sprout into the organoid compartments. Next, we demonstrated the viability of human stem-cell derived liver organoids in the organoid compartments. Finally, we show the possibility to circulate immune cells in the microfluidic channels that retain viability without being trapped or activated. The rOoC platform allows growing and connecting of two or more tissue or organ representations on-chip with the possibility of applying gradients, endothelial barriers, microvasculature and circulating cells independent of external tubing and support systems.

View all works in NVA