Interrogating the interplay between matrix topology, matrix stiffness and aortic smooth muscle cell function

Afewerki, Teclino (2022) Interrogating the interplay between matrix topology, matrix stiffness and aortic smooth muscle cell function. Doctoral thesis, University of East Anglia.

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Abstract

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the arterial wall and normally adopt a quiescent, contractile phenotype to regulate vascular tone. VSMCs are exposed to multiple mechanical cues, including stretch and matrix stiffness, which regulate VSMC contraction. Recent studies have shown that extracellular matrix (ECM) topology and stiffness influence the migration of a variety of cell types. Whilst we have extensive knowledge
of how soluble factors regulate VSMC function, our understanding of the importance of matrix-derived cues is limited.

In this study we use polyacrylamide hydrogels (PAHs) of physiological and pathological stiffness, to investigate the interplay between matrix topology, matrix stiffness and VSMC function. To mimic the in vivo features of VSMCs ECM, we used 3D printed micropatterns to develop grooved PAHs, and cells were cultured on smooth and grooved PAHs. VSMCs grown on grooved hydrogels of physiological stiffness were spindle-shaped, less spread than those grown on smooth hydrogels showing fried egg morphology.

Traction force microscopy revealed that VSMCs on the grooved hydrogels of physiological stiffness generated enhanced traction stress compared to their counterparts on smooth hydrogels. VSMCs on grooved hydrogels of pathological stiffness still generated enhanced traction stress however, they displayed similar spreading to VSMCs grown on smooth hydrogels. We also investigated the migrational capacity of VSMCs. VSMCs on grooved hydrogels of physiological stiffness displayed a reduced migrational capacity compared to their counterparts on smooth hydrogels. However, VSMC migrational capacity remained unaltered between grooved and smooth hydrogels of pathological stiffness. Finally, we tested the proliferation rate of VSMCs and the VSMCs on grooved showed a significantly lower proliferation rate than those on smooth PASs, on both healthy and aged/diseased stiffness.

We also investigated the role of novel regulators of VSMCs, however, because previous studies cultured cells on plastic or glass, the information we found wasn’t much help and we started with little understanding of their mechanism of action. We found out that the novel regulators of VSMCs’ function we used behave differently in different stiffness and topology. Hence, our data demonstrate that matrix topology and stiffness differentially regulate VSMC function and novel regulators respond differently to matrix alteration.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Pharmacy
Depositing User:	Chris White
Date Deposited:	20 Mar 2023 10:49
Last Modified:	20 Mar 2023 10:49
URI:	https://ueaeprints.uea.ac.uk/id/eprint/91576
DOI:

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