decellularization-of-the-murine-cardiopulmonary-complex

Decellularization of the Murine Cardiopulmonary Complex

We present here a decellularization protocol for mouse heart and lungs. It produces structural ECM scaffolds that can be used to analyze ECM topology and ...

extracting-young-s-modulus-native-murine-pulmonary-basement-membranes

Extracting the Young's Modulus of Native Murine Pulmonary Basement Membranes from Atomic Force Microscopy Derived Force Maps

Atomic force microscopy (AFM) allows the characterization of the mechanical properties of a sample with a spatial resolution of several tens of ...

University of Copenhagen (UCPH)

University of Freiburg

Members of the lysyl oxidase (LOX) family are secreted copper-dependent amine oxidases that catalyze the covalent crosslinking of collagens and elastin in the extracellular matrix (ECM), an essential process for the structural integrity of all tissues. LOX enzymes can also remodel the tumor microenvironment and have been implicated in all stages of tumor initiation and progression of many cancer types. Changes in the ECM can influence several cancer cell phenotypes. Integrin adhesion complexes (IACs) physically connect cells with their microenvironment. This review article summarizes the main findings on the role of LOX proteins in modulating the tumor microenvironment, with a particular focus on how ECM changes are integrated by IACs to modulate cells behavior. Finally, we discuss how the development of selective LOX inhibitors may lead to novel and effective therapies in cancer treatment.

Interplay Between LOX Enzymes and Integrins in the Tumor Microenvironment.

The extracellular matrix (ECM) is a major regulator of homeostasis and disease, yet the 3D structure of the ECM remains poorly understood because of limitations in ECM visualization. We recently developed an ECM-specialized method termed in situ decellularization of tissues (ISDoT) to isolate native 3D ECM scaffolds from whole organs in which ECM structure and composition are preserved. Here, we present detailed surgical instructions to facilitate decellularization of 33 different mouse tissues and details of validated antibodies that enable the visualization of 35 mouse ECM proteins. Through mapping of these ECM proteins, the structure of the ECM can be determined and tissue structures visualized in detail. In this study, perfusion decellularization is presented for bones, skeletal muscle, tongue, salivary glands, stomach, duodenum, jejunum/ileum, large intestines, mesentery, liver, gallbladder, pancreas, trachea, bronchi, lungs, kidneys, urinary bladder, ovaries, uterine horn, cervix, adrenal gland, heart, arteries, veins, capillaries, lymph nodes, spleen, peripheral nerves, eye, outer ear, mammary glands, skin, and subcutaneous tissue. Decellularization, immunostaining, and imaging take 4-5 d.

Decellularization and antibody staining of mouse tissues to map native extracellular matrix structures in 3D.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Decellularization and antibody staining of mouse tissues to map native extracellular matrix structures in 3D.

The basement membrane (BM) is a special type of extracellular matrix and presents the major barrier cancer cells have to overcome multiple times to form metastases. Here we show that BM stiffness is a major determinant of metastases formation in several tissues and identify netrin-4 (Net4) as a key regulator of BM stiffness. Mechanistically, our biophysical and functional analyses in combination with mathematical simulations show that Net4 softens the mechanical properties of native BMs by opening laminin node complexes, decreasing cancer cell potential to transmigrate this barrier despite creating bigger pores. Our results therefore reveal that BM stiffness is dominant over pore size, and that the mechanical properties of 'normal' BMs determine metastases formation and patient survival independent of cancer-mediated alterations. Thus, identifying individual Net4 protein levels within native BMs in major metastatic organs may have the potential to define patient survival even before tumour formation. The ratio of Net4 to laminin molecules determines BM stiffness, such that the more Net4, the softer the BM, thereby decreasing cancer cell invasion activity.

Basement membrane stiffness determines metastases formation.

The treatment of bone defects with recombinant bone morphogenetic protein-2 (BMP-2) requires high doses precluding broad clinical application. Here, a bioengineering approach is presented that strongly improves low-dose BMP-2-based bone regeneration by mobilizing healing-associated mesenchymal progenitor cells (MPCs). Smart synthetic hydrogels are used to trap and study endogenous MPCs trafficking to bone defects. Hydrogel-trapped and prospectively isolated MPCs differentiate into multiple lineages in vitro and form bone in vivo. In vitro screenings reveal that platelet-derived growth factor BB (PDGF-BB) strongly recruits prospective MPCs making it a promising candidate for the engineering of hydrogels that enrich endogenous MPCs in vivo. However, PDGF-BB inhibits BMP-2-mediated osteogenesis both in vitro and in vivo. In contrast, smart two-way dynamic release hydrogels with fast-release of PDGF-BB and sustained delivery of BMP-2 beneficially promote the healing of bone defects. Collectively, it is shown that modulating the dynamics of endogenous progenitor cells in vivo by smart synthetic hydrogels significantly improves bone healing and holds great potential for other advanced applications in regenerative medicine.

Smart Hydrogels for the Augmentation of Bone Regeneration by Endogenous Mesenchymal Progenitor Cell Recruitment.

Metastatic cancer spread is responsible for most cancer-related deaths. To colonize a new organ, invading cells adapt to, and remodel, the local extracellular matrix (ECM), a network of proteins and proteoglycans underpinning all tissues, and a critical regulator of homeostasis and disease. However, there is a major lack in tools to study cancer cell behavior within native 3D ECM. Here, an in-house designed bioreactor, where mouse organ ECM scaffolds are perfused and populated with cells that are challenged to colonize it, is presented. Using a specialized bioreactor chamber, it is possible to monitor cell behavior microscopically (e.g., proliferation, migration) within the organ scaffold. Cancer cells in this system recapitulate cell signaling observed in vivo and remodel complex native ECM. Moreover, the bioreactors are compatible with co-culturing cell types of different genetic origin comprising the normal and tumor microenvironment. This degree of experimental flexibility in an organ-specific and 3D context, opens new possibilities to study cell-cell and cell-ECM interplay and to model diseases in a controllable organ-specific system ex vivo.

Modeling Metastatic Colonization in a Decellularized Organ Scaffold-Based Perfusion Bioreactor.

All cells in multicellular organisms are housed in the extracellular matrix (ECM), an acellular edifice built up by more than a thousand proteins and glycans. Cells engage in a reciprocal relationship with the ECM; they build, inhabit, maintain, and remodel the ECM, while, in turn, the ECM regulates their behavior. The homeostatic balance of cell-ECM interactions can be lost, due to ageing, irritants or diseases, which results in aberrant cell behavior. The ECM can suppress or promote disease progression, depending on the information relayed to cells. Instructions come in the form of biochemical (e.g., composition), biophysical (e.g., stiffness), and topographical (e.g., structure) cues. While advances have been made in many areas, we only have a very limited grasp of ECM topography. A detailed atlas deciphering the spatiotemporal arrangement of all ECM proteins is lacking. We feel that such an extracellular matrix architecture (matritecture) atlas should be a priority goal for ECM research. In this commentary, we will discuss the need to resolve the spatiotemporal matritecture to identify potential disease triggers and therapeutic targets and present strategies to address this goal. Such a detailed matritecture atlas will not only identify disease-specific ECM structures but may also guide future strategies to restructure disease-related ECM patterns reverting to a normal pattern.

Matritecture: Mapping the extracellular matrix architecture during health and disease.

Netrin-1 is a bifunctional chemotropic guidance cue that plays key roles in diverse cellular processes including axon pathfinding, cell migration, adhesion, differentiation, and survival. Here, we present a molecular understanding of netrin-1 mediated interactions with glycosaminoglycan chains of diverse heparan sulfate proteoglycans (HSPGs) and short heparin oligosaccharides. Whereas interactions with HSPGs act as platform to co-localise netrin-1 close to the cell surface, heparin oligosaccharides have a significant impact on the highly dynamic behaviour of netrin-1. Remarkably, the monomer-dimer equilibrium of netrin-1 in solution is abolished in the presence of heparin oligosaccharides and replaced with highly hierarchical and distinct super assemblies leading to unique, yet unknown netrin-1 filament formation. In our integrated approach we provide a molecular mechanism for the filament assembly which opens fresh paths towards a molecular understanding of netrin-1 functions.

The dynamic nature of netrin-1 and the structural basis for glycosaminoglycan fragment-induced filament formation.

The desmoplastic reaction observed in many cancers is a hallmark of disease progression and prognosis, particularly in breast and pancreatic cancer. Stromal-derived extracellular matrix (ECM) is significantly altered in desmoplasia, and as such plays a critical role in driving cancer progression. Using fibroblast-derived matrices (FDMs), we show that cancer cells have increased growth on cancer associated FDMs, when compared to FDMs derived from non-malignant tissue (normal) fibroblasts. We assess the changes in ECM characteristics from normal to cancer-associated stroma at the primary tumor site. Compositional, structural, and mechanical analyses reveal significant differences, with an increase in abundance of core ECM proteins, coupled with an increase in stiffness and density in cancer-associated FDMs. From compositional changes of FDM, we derived a 36-ECM protein signature, which we show matches in large part with the changes in pancreatic ductal adenocarcinoma (PDAC) tumor and metastases progression. Additionally, this signature also matches at the transcriptomic level in multiple cancer types in patients, prognostic of their survival. Together, our results show relevance of FDMs for cancer modelling and identification of desmoplastic ECM components for further mechanistic studies.

Fibroblast-derived matrix models desmoplastic properties and forms a prognostic signature in cancer progression.

The aim of the present study was to describe an unselected population of patients with diagnosis of FIGO stage IV OC.

Characteristics, Treatment Patterns and Survival of International Federation of Gynecology and Obstetrics Stage IV Epithelial Ovarian Cancer-A Population-Based Study.

Mammalian cells sense and react to the mechanics of their immediate microenvironment. Therefore, the characterization of the biomechanical properties of tissues with high spatial resolution provides valuable insights into a broad variety of developmental, homeostatic and pathological processes within living organisms. The biomechanical properties of the basement membrane (BM), an extracellular matrix (ECM) substructure measuring only ∼100-400 nm across, are, among other things, pivotal to tumor progression and metastasis formation. Although the precise assignment of the Young's modulus E of such a thin ECM substructure especially in between two cell layers is still challenging, biomechanical data of the BM can provide information of eminent diagnostic potential. Here we present a detailed protocol to quantify the elastic modulus of the BM in murine and human lung tissue, which is one of the major organs prone to metastasis. This protocol describes a streamlined workflow to determine the Young's modulus E of the BM between the endothelial and epithelial cell layers shaping the alveolar wall in lung tissues using atomic force microscopy (AFM). Our step-by-step protocol provides instructions for murine and human lung tissue extraction, inflation of these tissues with cryogenic cutting medium, freezing and cryosectioning of the tissue samples, and AFM force-map recording. In addition, it guides the reader through a semi-automatic data analysis procedure to identify the pulmonary BM and extract its Young's modulus E using an in-house tailored user-friendly AFM data analysis software, the Center for Applied Tissue Engineering and Regenerative Medicine processing toolbox, which enables automatic loading of the recorded force maps, conversion of the force versus piezo-extension curves to force versus indentation curves, calculation of Young's moduli and generation of Young's modulus maps, where the pulmonary BM can be identified using a semi-automatic spatial filtering tool. The entire protocol takes 1-2 d.

Profiling native pulmonary basement membrane stiffness using atomic force microscopy.

Organ function depends on the three-dimensional integrity of the extracellular matrix (ECM). The structure resulting from the location and association of ECM components is a central regulator of cell behavior, but a dearth of matrix-specific analysis keeps it unresolved. Here, we deploy a high-resolution, 3D ECM mapping method and design a machine-learning powered pipeline to detect and characterize ECM architecture during health and disease. We deploy these tools in the human lung, an organ heavily dependent on ECM structure that can host diseases with different histopathologies. We analyzed segments from healthy, emphysema, usual interstitial pneumonia, sarcoidosis, and COVID-19 patients, and produced a remodeling signature per disease and a health/disease probability map from which we inferred the architecture of healthy and diseased ECM. Our methods demonstrate that exaggerated matrix deposition, or fibrosis, is not a single phenomenon, but a series of disease-specific alterations. STATEMENT OF SIGNIFICANCE: : The extracellular matrix, or ECM, is the foremost biomaterial. It shapes and supports all tissues while regulating all cells. ECM structure is intricate, yet precise: each organ, at every stage, has a specific ECM structure. During disease, tissues suffer from structural changes that accelerate and perpetuate illness by dysregulating cells. Both healthy and diseased ECM structures are of great biomedical importance, but surprisingly, they have not been mapped in detail. Here, we present a method that combines tissue engineering with machine learning to reveal, map and analyze ECM structures, applied it to pulmonary diseases that kill millions every year. This method can bring objectivity and a higher degree of confidence into the diagnosis of pulmonary disease. In addition the amount of tissue needed for a firm diagnosis may be much smaller than required for manual microscopy evaluation.

ArticleTotal : 2	Year
Publication title	2021
Publication title	2025

Article	Year
Interplay Between LOX Enzymes and Integrins in the Tumor Microenvironment. Cancers\| PubMed ID: 31130685	2019
Decellularization and antibody staining of mouse tissues to map native extracellular matrix structures in 3D. Nature protocols\| PubMed ID: 31705125	2019
Author Correction: Decellularization and antibody staining of mouse tissues to map native extracellular matrix structures in 3D. Nature protocols\| PubMed ID: 32203488	2020
Basement membrane stiffness determines metastases formation. Nature materials\| PubMed ID: 33495631	2021
Smart Hydrogels for the Augmentation of Bone Regeneration by Endogenous Mesenchymal Progenitor Cell Recruitment. Advanced science (Weinheim, Baden-Wurttemberg, Germany)\| PubMed ID: 32274319	2020
Modeling Metastatic Colonization in a Decellularized Organ Scaffold-Based Perfusion Bioreactor. Advanced healthcare materials\| PubMed ID: 34734500	2022
Matritecture: Mapping the extracellular matrix architecture during health and disease. Matrix biology plus\| PubMed ID: 35243299	2022
The dynamic nature of netrin-1 and the structural basis for glycosaminoglycan fragment-induced filament formation. Nature communications\| PubMed ID: 36869049	2023
Fibroblast-derived matrix models desmoplastic properties and forms a prognostic signature in cancer progression. Frontiers in immunology\| PubMed ID: 37539058	2023
Characteristics, Treatment Patterns and Survival of International Federation of Gynecology and Obstetrics Stage IV Epithelial Ovarian Cancer-A Population-Based Study. Cancers\| PubMed ID: 38067378	2023
Profiling native pulmonary basement membrane stiffness using atomic force microscopy. Nature protocols\| PubMed ID: 38429517	2024
Machine Learning identifies remodeling patterns in human lung extracellular matrix. Acta biomaterialia\| PubMed ID: 39746529	2024

Raphael Reuten

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