title: Extracellular matrix of adipogenically differentiated mesenchymal stem cells reveals a network of collagen filaments, mostly interwoven by hexagonal structural units.
abstract: Extracellular matrix (ECM) is the non-cellular component of tissues, which not only provides biological shelter but also takes part in the cellular decisions for diverse functions. Every tissue has an ECM with unique composition and topology that governs the process of determination, differentiation, proliferation, migration and regeneration of cells. Little is known about the structural organization of matrix especially of MSC-derived adipogenic ECM. Here, we particularly focus on the composition and architecture of the fat ECM to understand the cellular behavior on functional bases. Thus, mesenchymal stem cells (MSC) were adipogenically differentiated, then, were transferred to adipogenic propagation medium, whereas they started the release of lipid droplets leaving bare network of ECM. Microarray analysis was performed, to indentify the molecular machinery of matrix. Adipogenesis was verified by Oil Red O staining of lipid droplets and by qPCR of adipogenic marker genes PPARG and FABP4. Antibody staining demonstrated the presence of collagen type I, II and IV filaments, while alkaline phosphatase activity verified the ossified nature of these filaments. In the adipogenic matrix, the hexagonal structures were abundant followed by octagonal structures, whereas they interwoven in a crisscross manner. Regarding molecular machinery of adipogenic ECM, the bioinformatics analysis revealed the upregulated expression of COL4A1, ITGA7, ITGA7, SDC2, ICAM3, ADAMTS9, TIMP4, GPC1, GPC4 and downregulated expression of COL14A1, ADAMTS5, TIMP2, TIMP3, BGN, LAMA3, ITGA2, ITGA4, ITGB1, ITGB8, CLDN11. Moreover, genes associated with integrins, glycoproteins, laminins, fibronectins, cadherins, selectins and linked signaling pathways were found. Knowledge of the interactive-language between cells and matrix could be beneficial for the artificial designing of biomaterials and bioscaffolds.
authors.affiliation: Tissue Engineering Laboratory & Berlin-Brandenburg Center for Regenerative Therapies, Dept. of Rheumatology and Clinical Immunology, Charité-University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany. Electronic address: mujib.ullah@charite.de.
authors.forename: Mujib
authors.initials: M
authors.lastname: Ullah
authors.forename: Michael
authors.initials: M
authors.lastname: Sittinger
authors.forename: Jochen
authors.initials: J
authors.lastname: Ringe
mesh_terms: D050156:Adipogenesis / Q000502:physiology*; D001391:Azo Compounds; D002454:Cell Differentiation / Q000502:physiology*; D003094:Collagen / Q000378:metabolism* / Q000648:ultrastructure; D019295:Computational Biology; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics*; D006652:Histological Techniques; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D046228:Microarray Analysis; D047495:PPAR gamma / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics*
chemical_list: D001391:Azo Compounds; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D008565:Membrane Proteins; D047495:PPAR gamma; D003094:Collagen; C011049:oil red O
keywords: Cadherins; ECM; Integrins; Lipid droplets; Matrix signaling; Selectins