Download or read book Impact of Extracellular Matrix Structure and Integrin Expression on Human Fibroblast Phenotype written by Nicholas Joseph Merna and published by . This book was released on 2014 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extracellular matrix (ECM) derived from whole organ decellularization offers a promising biological scaffold for tissue engineering applications. The native 3D structure and biochemical composition of these matrices can potentially support tissue-specific recellularization strategies. However, decellularization protocols use reagents that can disrupt the ECM resulting in a range of mechanical properties and protein composition. By identifying structural and biochemical features of the ECM that impact cell behavior, we can tailor decellularization protocols to retain those features. Recellularization of decellularized matrices is an intriguing strategy to engineer lung and cardiac tissue that will likely include the fibroblast. However, excessive collagen deposition by fibroblasts could interfere with normal structure and function of the surrounding tissue. Furthermore, integrin expression can influence the expression of intracellular structural proteins such as alpha smooth muscle actin ([alpha]-SMA), and extracellular structural proteins such as collagen. However, previous work has not determined the effect of decellularized ECM on fibroblast function and integrin signaling. In this work, we used multiphoton microscopy (MPM), combined with image correlation spectroscopy (ICS), to characterize structural and mechanical properties of the decellularized cardiac matrix in a non-invasive and non-destructive fashion. ICS amplitude of second harmonic generation (SHG) collagen images (collagen content) and ICS ratio of two-photon fluorescence (TPF) elastin images (elastin alignment) strongly correlated with compressive modulus. We then seeded cardiac and lung fibroblasts on cardiac ECM, lung ECM and their components to determine the effect of substrate composition, tissue specificity and integrin expression on fibroblast phenotype. [alpha]-SMA expression increased for stiffer substrates, and lung fibroblasts expressed significantly higher levels of [alpha]-SMA than cardiac fibroblasts. Higher expression of [beta]3 integrins in cardiac fibroblasts, combined with increased [alpha]-SMA expression resulting from functional blocking of [beta]3 integrins, demonstrates that [beta]3 plays an important role in regulating cardiac fibroblast phenotype. Our findings indicate that ECM stiffness strongly correlates with collagen and elastin alignment in the ECM following decellularization, which can potentially impact fibroblast collagen and [alpha]-SMA expression during recellularization. Furthermore, differential expression of [beta]3 integrins in organ-specific fibroblasts impacts [alpha]-SMA expression suggesting that both stromal cell source and ECM structure can impact the remodeling response during recellularization.