Stiffness and Extracellular Matrix Coating

Ella Stasko

Last edited: 06.25.2024

In this project we are working to further understand the pathogenesis of pulmonary arterial hypertension (PAH). In this disease, pulmonary vasculature becomes dynamically obstructed by vasoconstriction, structurally obstructed by adverse vascular remodeling and pathologically non-compliant. Increased proliferation of pulmonary arterial smooth muscle cells (PASMC) is a hallmark of this disease. This thickens vasculature and a phenotypic switching of PASMC to contractile phenotype is also observed. This contributes to increased resistance to blood flow and increased heart pressure. The working hypothesis of PAH includes a negative feedback loop where increased proliferation increases stiffness and, in turn, increased stiffness increases proliferation.

In the lab, Ella is currently working to validate the work done by Issac Downs in his master’s thesis (completed 2023). Here, he aimed to establish whether coatings with protein content specific to pulmonary vasculature elicit differing PASMC responses as compared to non-specific coatings and investigating the effect of ECM stiffness on PASMC behavior.

To do this, PASMC are cultured on stiffness plates of 0.2kPa, 0.5kPa, 2kPa and 8kPa. The plates were chosen to reflect lungs less stiff than healthy lung, of healthy lung and of fibrotic lung. Each plate was coated in either PureCol or with healthy human vascular extracellular matrix (vECM). Click here to see how we prepare vECM in the Weiss Lab!

Imaging, metabolic activity and gene expression are used for end point analysis. Thus far results have been consistent and positive. It suggests that ECM composition, stiffness and the interaction between stiffness and coating influence metabolic activity of PASMCs, quantified by AlamarBlue assay. Thus far, results in gene expression have been less conclusive.

As the project takes on new directions, pulmonary vascular endothelial cells (PVEC) will be cultured under the same conditions as the PASMCs. In PAH, proliferation of PVECs is also observed and is known to similarly contribute to PAH progression. This work was started by Blythe Hattenbach in 2024 as she completed her senior thesis for an undergraduate degree in biomedical engineering. As with PASMCs, preliminary results show that PVEC metabolic activity varies based on coating type. This work will be further explored in the lab by Ella.