Lower respiratory diseases are currently the third leading cause of death worldwide. For many end-stage patients with these diseases, there is no cure and a shortage of donor organs available for transplant. A promising solution is to design regenerative scaffolds or complete bioengineered lungs, using decellularized lung tissues as a template for regeneration. Recent advances in the field have made significant strides towards developing a transplantable lung. However, the current technology has not produced a functional lung for in vivo transplant due to immature gas exchange barriers. The mechanisms driving alveolar barrier maturation and role that extracellular matrix (ECM) plays within the strengthening of each type of junction are not fully understood. This research has characterized and tailored a decellularized ECM (dECM) coating for the in vitro study of dECM component depletion and potential effects on cell barrier function, attachment, and survival. Adjustments to dECM digestion duration drastically changed the resulting structural and biochemical properties for each cellular microenvironment. Shorter digestion time resulted in a dense branching of the ECM architecture and biomimetic mechanical properties needed for epithelial culture. Also, through systematic supplementation of essential basement membrane (BM) proteins to dECM, we have found that supplementation with laminin enhanced barrier strength by ZO-1 junction stabilization. This indicates that dECM can promote barrier formation but may have lost vital proteins that need to be replenished. Laminin-mediated barrier function was determined to be caused by the upregulation of the Epac/Rap1 pathway. This pathway has previously been implicated in lung endothelial barriers but not alveolar epithelial junction strengthening. Finally, to establish the translatability of these findings to whole lung recellularization, the dECM coating was used to pre-treat the airways of decellularized lungs for recellularization. Culture of MLE12 mouse epithelial cells into dECM-coated lungs increased cell survival and distribution. In combination with dECM coatings, rotational cell seeding improved cell dispersal and viability. Altogether, these techniques, devised to promote healthy alveolar barriers, are vital to enhancing current lung recellularization strategies and the treatment of many edema-associated pulmonary diseases.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-7071 |
| Date | 01 January 2019 |
| Creators | Young, Bethany M |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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