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Publikation A perfused in vitro human iPSC-derived blood–brain barrier faithfully mimics transferrin receptor-mediated transcytosis of therapeutic antibodies(Springer, 2023) Burgio, Floriana; Gaiser, Carine; Brady, Kevin; Gatta, Viviana; Class, Reiner; Schrage, Ramona; Suter-Dick, LauraDelivering biologics to elicit a therapeutic response in the central nervous system (CNS) remains challenging due to the presence of the blood brain barrier (BBB). Receptor-mediated transcytosis is a strategy to improve brain exposure after systemic drug administration. The availability of a clinically relevant in vitro BBB model is crucial to investigate transcytosis pathways and to predict the penetration of biologics into the CNS. We created a perfused human in vitro BBB model made of induced pluripotent stem cells (iPSC)-derived brain microvascular endothelial cells (BMEC) for studying transferrin receptor-mediated transcytosis. iPSC-derived BMEC were seeded in the top channel of a three-lane microfluidic device (OrganoPlate®). After 2 days in culture, the established cell model exhibited relevant BBB features, including physiological transendothelial electrical resistance in a transwell setting (1500 Ω*cm), reduced apparent permeability (Papp) to the fluorescence tracer Lucifer yellow (20-fold less than cell-free chips), expression of key BBB markers such as tight junctions proteins, transporters, receptors and functional P-gp efflux pump. Moreover, the model exhibited functional transferrin receptor-mediated uptake and transcytosis. To assess selective transferrin receptor-mediated transcytosis, a mixture of anti-human transferrin receptor (MEM-189) and control (sheep IgG anti-bovine serum albumin) antibodies was perfused in the top channel for 2 h. The Papp of MEM-189 was 11-fold higher than that of the control antibody, demonstrating facilitated receptor-mediated transcytosis. Compared to published work reporting a 2-fold ratio, this result is remarkable and establishes the suitability of our model for exploring receptor-mediated transcytosis and screening of antibodies for putative brain shuttle application. A perfused in vitro human model made of iPSC-derived BMEC with the chief characteristics (barrier tightness, functionality) of the human BBB can be applied to study transferrin receptor (TfR)-mediated transcytosis of therapeutic antibodies. This may bring critical advances in drug shuttle technology. Graphical abstract generated with biorender.com.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Electrospun decellularized extracellular matrix scaffolds promote the regeneration of injured neurons(Elsevier, 09/2023) Mungenast, Lena; Nieminen, Ronya; Gaiser, Carine; Faia-Torres, Ana Bela; Rühe, Jürgen; Suter-Dick, Laura01A - Beitrag in wissenschaftlicher ZeitschriftPublikation In vitro to in vivo extrapolation and high-content imaging for simultaneous characterization of chemically induced liver steatosis and markers of hepatotoxicity(Springer, 12.04.2023) Müller, Fabrice A.; Stamou, Marianna; Englert, Felix H.; Frenzel, Ole; Diedrich, Sabine; Suter-Dick, Laura; Wambaugh, John F.; Sturla, Shana J.Chemically induced steatosis is characterized by lipid accumulation associated with mitochondrial dysfunction, oxidative stress and nucleus distortion. New approach methods integrating in vitro and in silico models are needed to identify chemicals that may induce these cellular events as potential risk factors for steatosis and associated hepatotoxicity. In this study we used high-content imaging for the simultaneous quantification of four cellular markers as sentinels for hepatotoxicity and steatosis in chemically exposed human liver cells in vitro. Furthermore, we evaluated the results with a computational model for the extrapolation of human oral equivalent doses (OED). First, we tested 16 reference chemicals with known capacities to induce cellular alterations in nuclear morphology, lipid accumulation, mitochondrial membrane potential and oxidative stress. Then, using physiologically based pharmacokinetic modeling and reverse dosimetry, OEDs were extrapolated from data of any stimulated individual sentinel response. The extrapolated OEDs were confirmed to be within biologically relevant exposure ranges for the reference chemicals. Next, we tested 14 chemicals found in food, selected from thousands of putative chemicals on the basis of structure-based prediction for nuclear receptor activation. Amongst these, orotic acid had an extrapolated OED overlapping with realistic exposure ranges. Thus, we were able to characterize known steatosis-inducing chemicals as well as data-scarce food-related chemicals, amongst which we confirmed orotic acid to induce hepatotoxicity. This strategy addresses needs of next generation risk assessment and can be used as a first chemical prioritization hazard screening step in a tiered approach to identify chemical risk factors for steatosis and hepatotoxicity-associated events.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Directional submicrofiber hydrogel composite scaffolds supporting neuron differentiation and enabling neurite alignment(MDPI, 29.09.2022) Selvi, Jasmin; Faia-Torres, Ana Bela; Rühe, Jürgen; Züger, Fabian; Suter-Dick, Laura; Mungenast, Lena; Gullo, MaurizioCell cultures aiming at tissue regeneration benefit from scaffolds with physiologically relevant elastic moduli to optimally trigger cell attachment, proliferation and promote differentiation, guidance and tissue maturation. Complex scaffolds designed with guiding cues can mimic the anisotropic nature of neural tissues, such as spinal cord or brain, and recall the ability of human neural progenitor cells to differentiate and align. This work introduces a cost-efficient gelatin-based submicron patterned hydrogel–fiber composite with tuned stiffness, able to support cell attachment, differentiation and alignment of neurons derived from human progenitor cells. The enzymatically crosslinked gelatin-based hydrogels were generated with stiffnesses from 8 to 80 kPa, onto which poly(ε-caprolactone) (PCL) alignment cues were electrospun such that the fibers had a preferential alignment. The fiber–hydrogel composites with a modulus of about 20 kPa showed the strongest cell attachment and highest cell proliferation, rendering them an ideal differentiation support. Differentiated neurons aligned and bundled their neurites along the aligned PCL filaments, which is unique to this cell type on a fiber–hydrogel composite. This novel scaffold relies on robust and inexpensive technology and is suitable for neural tissue engineering where directional neuron alignment is required, such as in the spinal cord.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Apical medium flowiInfluences the morphology and physiology of human proximal tubular cells in a microphysiological system(MDPI, 30.09.2022) Specioso, Gabriele; Bovard, David; Zanetti, Filippo; Maranzano, Fabio; Merg, Céline; Sandoz, Antonin; Titz, Bjoern; Dalcanale, Federico; Hoeng, Julia; Renggli, Kasper; Suter-Dick, LauraThere is a lack of physiologically relevant in vitro human kidney models for disease modelling and detecting drug-induced effects given the limited choice of cells and difficulty implementing quasi-physiological culture conditions. We investigated the influence of fluid shear stress on primary human renal proximal tubule epithelial cells (RPTECs) cultured in the micro-physiological Vitrofluid device. This system houses cells seeded on semipermeable membranes and can be connected to a regulable pump that enables controlled, unidirectional flow. After 7 days in culture, RPTECs maintained physiological characteristics such as barrier integrity, protein uptake ability, and expression of specific transporters (e.g., aquaporin-1). Exposure to constant apical side flow did not cause cytotoxicity, cell detachment, or intracellular reactive oxygen species accumulation. However, unidirectional flow profoundly affected cell morphology and led to primary cilia lengthening and alignment in the flow direction. The dynamic conditions also reduced cell proliferation, altered plasma membrane leakiness, increased cytokine secretion, and repressed histone deacetylase 6 and kidney injury molecule 1 expression. Cells under flow also remained susceptible to colistin-induced toxicity. Collectively, the results suggest that dynamic culture conditions in the Vitrofluid system promote a more differentiated phenotype in primary human RPTECs and represent an improved in vitro kidney model.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Methotrexate-induced liver injury is associated with oxidative stress, impaired mitochondrial respiration, and endoplasmic reticulum stress in vitro(MDPI, 01.12.2022) Schmidt, Saskia; Messner, Catherine; Gaiser, Carine; Hämmerli, Carina; Suter-Dick, LauraLow-dose methotrexate (MTX) is a standard therapy for rheumatoid arthritis due to its low cost and efficacy. Despite these benefits, MTX has been reported to cause chronic drug-induced liver injury, namely liver fibrosis. The hallmark of liver fibrosis is excessive scarring of liver tissue, triggered by hepatocellular injury and subsequent activation of hepatic stellate cells (HSCs). However, little is known about the precise mechanisms through which MTX causes hepatocellular damage and activates HSCs. Here, we investigated the mechanisms leading to hepatocyte injury in HepaRG and used immortalized stellate cells (hTERT-HSC) to elucidate the mechanisms leading to HSC activation by exposing mono- and co-cultures of HepaRG and hTERT-HSC to MTX. The results showed that at least two mechanisms are involved in MTX-induced toxicity in HepaRG: (i) oxidative stress through depletion of glutathione (GSH) and (ii) impairment of cellular respiration in a GSH-independent manner. Furthermore, we measured increased levels of endoplasmic reticulum (ER) stress in activated HSC following MTX treatment. In conclusion, we established a human-relevant in vitro model to gain mechanistical insights into MTX-induced hepatotoxicity, linked oxidative stress in HepaRG to a GSH-dependent and -independent pathway, and hypothesize that not only oxidative stress in hepatocytes but also ER stress in HSCs contribute to MTX-induced activation of HSCs.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation 3D printed microfluidic modules. Passive mixers and cells encapsulation in alginate(De Gruyter, 02.09.2022) Dalcanale, Federico; Caj, Michaela; Schuler, Felix; Ganeshanathan, Kireedan; Suter-Dick, LauraPassive mixers and droplet generation microfluidic chip modules were designed and manufactured using a commercial SLA 3D-printer. The mixing modules were designed specifically for 3D-printing and evaluated using FEM modeling. The co-flow droplet generator was used for cancer cells encapsulation and drug potency evaluation.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Single Cell Gene Expression analysis in a 3D microtissue liver model reveals cell type-specific responses to pro-fibrotic TGF-β1 stimulation(MDPI, 22.04.2021) Messner, Catherine; Babrak, Lmar; Titolo, Gaia; Caj, Michaela; Miho, Enkelejda; Suter-Dick, Laura3D cell culture systems are widely used to study disease mechanisms and therapeutic interventions. Multicellular liver microtissues (MTs) comprising HepaRG, hTERT-HSC and THP-1 maintain multicellular interactions and physiological properties required to mimic liver fibrosis. However, the inherent complexity of multicellular 3D-systems often hinders the discrimination of cell type specific responses. Here, we aimed at applying single cell sequencing (scRNA-seq) to discern the molecular responses of cells involved in the development of fibrosis elicited by TGF-β1. To obtain single cell suspensions from the MTs, an enzymatic dissociation method was optimized. Isolated cells showed good viability, could be re-plated and cultured in 2D, and expressed specific markers determined by scRNA-seq, qRT-PCR, ELISA and immunostaining. The three cell populations were successfully clustered using supervised and unsupervised methods based on scRNA-seq data. TGF-β1 led to a fibrotic phenotype in the MTs, detected as decreased albumin and increased αSMA expression. Cell-type specific responses to the treatment were identified for each of the three cell types. They included HepaRG damage characterized by a decrease in cellular metabolism, prototypical inflammatory responses in THP-1s and extracellular matrix remodeling in hTERT-HSCs. Furthermore, we identified novel cell-specific putative fibrosis markers in hTERT-HSC (COL15A1), and THP-1 (ALOX5AP and LAPTM5).01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Identification of miR-199a-5p, miR-214-3p and miR-99b-5p as fibrosis-specific extracellular biomarkers and promoters of HSC activation(MDPI, 2021) Suter-Dick, Laura; Messner, Catherine; Özkul, Dilek; Gaiser, Carine; Schmidt, Saskia; Terraciano, Luigi; Krähenbühl, StephanLiver fibrosis is characterized by the accumulation of extracellular matrix (ECM) resulting in the formation of fibrous scars. In the clinic, liver biopsies are the standard diagnostic method despite the potential for clinical complications. miRNAs are single-stranded, non-coding RNAs that can be detected in tissues, body fluids and cultured cells. The regulation of many miRNAs has been linked to tissue damage, including liver fibrosis in patients, resulting in aberrant miRNA expression/release. Experimental evidence also suggests that miRNAs are regulated in a similar manner in vitro and could thus serve as translational in vitro–in vivo biomarkers. In this work, we set out to identify and characterize biomarkers for liver fibrosis that could be used in vitro and clinically for research and diagnostic purposes. We focused on miRNAs released from hepatic 3D cultures exposed to methotrexate (MTX), which causes fibrosis, and acetaminophen (APAP), an acute hepatotoxicant with no clinically relevant association to liver fibrosis. Using a 3D in vitro model, we corroborated compound-specific responses as we show MTX induced a fibrotic response, and APAP did not. Performing miRNA-seq of cell culture supernatants, we identified potential miRNA biomarkers (miR-199a-5p, miR-214-3p, niRNA-125a-5p and miR-99b-5p) that were associated with a fibrotic phenotype and not with hepatocellular damage alone. Moreover, transfection of HSC with miR-199a-5p led to decreased expression of caveolin-1 and increased α-SMA expression, suggesting its role in HSC activation. In conclusion, we propose that extracellular miR-214-3p, miR-99b-5p, miR-125a-5p and specifically miR-199a-5p could contribute towards a panel of miRNAs for identifying liver fibrosis and that miR-199a-5p, miR-214-3p and miR-99b-5p are promoters of HSC activation.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Nephroscreen. A robust and versatile renal tubule-on-a-chip platform for nephrotoxicity assessment(Elsevier, 03/2021) Suter-Dick, Laura; Vriend, Jelle; Vormann, Marianne; Lanz, Henriette; Joore, Jos; Trietsch, Sebastian J.; Russel, Frans; Jacobsen, Björn; Roth, Adrian; Lu, Shuyan; Polli, Joseph; Naidoo, Anita; Masereeuw, Rosalinde; Wilmer, MartijnProximal tubule epithelial cells are the main driver of renal transport and secretion of xenobiotics, making them susceptible to drug-induced kidney injury. Cell-based assays are a meaningful alternative to animal testing to detect nephrotoxicity and contribute to the 3Rs (refine, reduce, replace animal experimentation). Here we report on a high-throughput, three-dimensional microfluidic platform (Nephroscreen) to detect drug-induced nephrotoxicity. Toxicologically relevant parameters were used to assess cell viability, functional epithelial barrier integrity, and interactions with specific transporters (P-glycoprotein: P-gp and multidrug resistance–associated protein 2/4: MRP2/4). Nephroscreen allowed the combination of a variety of read-outs, including imaging, extracellularly released markers, intracellular markers, and functional assays. Nephroscreen is compatible with automated pipetting, proved to be amenable to long-term experiments (at least 11 days), and was easily transferred between laboratories. The compelling data originate from several published reports on the development and implementation of this platform to detect nephrotoxicity and drug–transporter interactions. The reports demonstrate that Nephroscreen could be used to detect the nephrotoxic liabilities of the tested compounds. Future directions should include additional test compounds and thorough validation of its performance.01A - Beitrag in wissenschaftlicher Zeitschrift