Publications

Cardiac fibrosis occurs following insults to the myocardium and is characterized by the abnormal accumulation of non-compliant extracellular matrix (ECM), which compromises cardiomyocyte contractile activity and eventually leads to heart failure. This phenomenon is driven by the activation of cardiac fibroblasts (cFbs) to myofibroblasts and results in changes in ECM biochemical, structural and mechanical properties. The lack of predictive in vitro models of heart fibrosis has so far hampered the search for innovative treatments, as most of the cellular-based in vitro reductionist models do not take into account the leading role of ECM cues in driving the progression of the pathology. Here, we devised a single-step decellularization protocol to obtain and thoroughly characterize the biochemical and micro-mechanical properties of the ECM secreted by activated cFbs differentiated from human induced pluripotent stem cells (iPSCs). We activated iPSC-derived cFbs to the myofibroblast phenotype by tuning basic fibroblast growth factor (bFGF) and transforming growth factor beta 1 (TGF-beta 1) signalling and confirmed that activated cells acquired key features of myofibroblast phenotype, like SMAD2/3 nuclear shuttling, the formation of aligned alpha-smooth muscle actin (alpha- SMA)-rich stress fibres and increased focal adhesions (FAs) assembly. Next, we used Mass Spectrometry, nanoindentation, scanning electron and confocal microscopy to unveil the characteristic composition and the visco-elastic properties of the abundant, collagen-rich ECM deposited by cardiac myofibroblasts in vitro. Finally, we demonstrated that the fibrotic ECM activates mechanosensitive pathways in iPSC-derived cardiomyocytes, impacting on their shape, sarcomere assembly, phenotype, and calcium handling properties. We thus propose human bio-inspired decellularized matrices as animal-free, isogenic cardiomyocyte culture substrates recapitulating key pathophysiological changes occurring at the cellular level during cardiac fibrosis.

JTD Keywords: Adhesio, Cardiac fibrosis modelling, Decellularized extracellular matrix, Differentiation, Expression, Fibroblast activation, Fibronectin, Heart, Induced pluripotent stem cells, Ipsc-derived-cardiac fibroblasts, Ipsc-derived-cardiomyocyte, Myocardial-infarction, Neonatal cardiomyocytes, Smooth muscle actin, Substrate stiffness

To date, strategies aiming to modulate cell to extracellular matrix (ECM) interactions during organoid derivation remain largely unexplored. Here renal decellularized ECM (dECM) hydrogels are fabricated from porcine and human renal cortex as biomaterials to enrich cell-to-ECM crosstalk during the onset of kidney organoid differentiation from human pluripotent stem cells (hPSCs). Renal dECM-derived hydrogels are used in combination with hPSC-derived renal progenitor cells to define new approaches for 2D and 3D kidney organoid differentiation, demonstrating that in the presence of these biomaterials the resulting kidney organoids exhibit renal differentiation features and the formation of an endogenous vascular component. Based on these observations, a new method to produce kidney organoids with vascular-like structures is achieved through the assembly of hPSC-derived endothelial-like organoids with kidney organoids in 3D. Major readouts of kidney differentiation and renal cell morphology are assessed exploiting these culture platforms as new models of nephrogenesis. Overall, this work shows that exploiting cell-to-ECM interactions during the onset of kidney differentiation from hPSCs facilitates and optimizes current approaches for kidney organoid derivation thereby increasing the utility of these unique cell culture platforms for personalized medicine. Natural hydrogels derived from decellularized porcine or human kidney tissues are used to generate kidney organoids from human pluripotent stem cells, resulting in the enrichment of organoids' endogenous vascular component and improved renal differentiation. Exploiting the autonomous capacity of kidney organoids to exhibit endogenous vascularization in combination with these biomaterials, a novel approach is established to generate endothelial-kidney assembloids showing vascular-like structures. image

JTD Keywords: Angiogenesis, Animals, Assembloids, Biocompatible materials, Cell differentiation, Decellularized extracellular matrix, Extracellular matrix, Extracellular matrix-derived hydrogels, Extracellular matrix‐derived hydrogels, Extracellular-matrix, Human pluripotent stem cells, Humans, Hydrogels, Kidney, Kidney organoids, Neovascularization, physiologic, Organoids, Pluripotent stem cells, Pluripotent stem-cells, Swine, Tissu, Tissue engineering, Vascularizatio, Vascularization

Most morphogenetic and pathological processes are driven by cells responding to the surrounding matrix, such as its composition, architecture, and mechanical properties. Despite increasing evidence for the role of extracellular matrix (ECM) in tissue and disease development, many in vitro substitutes still fail to effectively mimic the native microenvironment. We established a novel method to produce macroscale (>1 cm) mesenchymal cell-derived matrices (CDMs) aimed to mimic the fibrotic tumor microenvironment surrounding epithelial cancer cells. CDMs are produced by human adipose mesenchymal stem cells cultured in sacrificial 3D scaffold templates of fibronectin-coated poly-lactic acid microcarriers (MCs) in the presence of macromolecular crowders. We showed that decellularized CDMs closely mimic the fibrillar protein composition, architecture, and mechanical properties of human fibrotic ECM from cancer masses. CDMs had highly reproducible composition made of collagen types I and III and fibronectin ECM with tunable mechanical properties. Moreover, decellularized and MC-free CDMs were successfully repopulated with cancer cells throughout their 3D structure, and following chemotherapeutic treatment, cancer cells showed greater doxorubicin resistance compared to 3D culture in collagen hydrogels. Collectively, these results support the use of CDMs as a reproducible and tunable tool for developing 3D in vitro cancer models.

JTD Keywords: 3d cell-derived matrices, adipose mesenchymal stem cells, collagen matrix, colorectal adenocarcinoma, cytotoxicity assay, deposition, expansion, extracellular microenvironment, extracellular-matrix, fibronectin, growth, macromolecular crowders, microcarriers, scaffolds, tissue, 3d cell-derived matrices, Adipose mesenchymal stem cells, Antineoplastic agents, Cell culture techniques, three dimensional, Cell line, tumor, Cell survival, Cytotoxicity assay, Decellularized extracellular matrix, Doxorubicin, Drug resistance, neoplasm, Extracellular microenvironment, Humans, Macromolecular crowders, Mesenchymal stem cells, Mesenchymal stem-cells, Microcarriers, Models, biological, Proof of concept study, Tissue scaffolds, Tumor microenvironment