Advisor(s)

Mary Kathryn Sewell-Loftin

Committee Member(s)

Jillian Richter
Palaniappan Sethu
Prasanna Krishnamurthy
Renata Jaskula-Sztul

Document Type

Dissertation

Date of Award

1-27-2026

Degree Name

Doctor of Philosophy (PhD)

School

Joint Health Sciences (Interdisciplinary)

Department

Biomedical Engineering

Abstract

Peripheral artery disease (PAD) affects millions worldwide, causing tissue ischemia and impaired healing due to insufficient blood flow. Current therapeutic strategies to promote revascularization remain limited, largely because the mechanical regulation of angiogenesis is poorly understood. While biochemical growth factors like VEGF have been extensively studied, the role of mechanical forces generated by stromal cells in the perivascular matrix remains underexplored. This dissertation investigated how stromal cell contractility drives vascular growth through mechanotransduction pathways and modulation of endothelial cell-cell junctions. Using 3D fibrin or fibrin-collagen-I-based microtissues and compartmentalized microfluidic devices, we characterized the mechanical phenotypes of multiple fibroblast populations and their effects on endothelial cell behavior. Matrix deformation assays revealed significant heterogeneity in fibroblast contractility, with dermal fibroblasts (NHDFs) generating the largest matrix deformations, followed by lung fibroblasts (NHLFs) and cardiac fibroblasts (NHCFs). Co-culture experiments demonstrated that highly contractile fibroblasts upregulated N-cadherin expression in endothelial cells and enhanced vascular network formation. Importantly, pharmacological inhibition of YAP/TAZ with verteporfin suppressed this contractility-driven angiogenesis, identifying YAP/TAZ mechanotransduction as a critical mediator linking stromal cell forces to endothelial responses. To decouple mechanical from biochemical signaling, compartmentalized microfluidic devices spatially separated endothelial and stromal cell populations while maintaining mechanical coupling through a shared extracellular matrix and communication ports. Results confirmed that highly contractile fibroblasts promoted endothelial sprouting into adjacent chambers without direct cell-cell contact. Furthermore, magnetic microbeads used to deliver mechanical strain independently of cellular biochemical signaling were sufficient to drive angiogenesis, providing definitive evidence that mechanical forces alone can promote vascular growth. Proteomic analysis revealed distinct secretome profiles among fibroblast populations; however, these biochemical differences did not fully account for the observed variations in angiogenic potential, establishing mechanical cues as the primary drivers. Additionally, matrix metalloprotease profiling revealed that endothelial-fibroblast co-culture selectively upregulated MMP-1, TIMP-1, and TIMP-2 compared to single cultures, indicating enhanced matrix remodeling activity. In contrast, global cytokine and growth factor secretion remained largely stable across all conditions, suggesting that stromal-endothelial crosstalk primarily modulates matrix protease networks rather than broad growth factor signaling. These findings demonstrate that stromal cell contractility actively regulates vascular growth and identify YAP/TAZ signaling and cadherin-mediated junctions as promising therapeutic targets for ischemic diseases. This work provides a mechanistic framework and translational platform for developing mechanically informed revascularization strategies to treat PAD and other cardiovascular conditions.

Keywords

angiogenesis;cadherins;extracellular matrix;mechanotransduction;peripheral artery disease;stromal cells

ProQuest Publication Number

32283821

ISBN

9798273379732

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