Biomimetic Vascular Matrix for Vascular Smooth Muscle Cell Mechanobiology and Pathology

SUMMARY
Arterial stiffness is a key risk factor for cardiovascular disease (CVD) events. A change in arterial
stiffness is a significant pathology in vascular injury, atherosclerosis, and coronary disease. Stiffening
of the vessel wall promotes anomalous migration and proliferation of vascular smooth muscle cells
(VSMCs), leading to neointima formation on the vessel wall. It is not clear, however, how the
extracellular matrix (ECM) influences these pathological processes. This research proposal will address
this by exploring how changes in arterial stiffness elicit VSMC behaviors that contribute to cardiovascular
disease. Specifically, this work draws upon preliminary data revealing that the protein survivin is a key
regulator of stiffness-mediated VSMC proliferation and migration and an effector of arterial stiffening
and remodeling. Using mouse and human VSMCs, we will first explore how vascular ECM stiffness
impacts VSMC migration, proliferation, and chromatin organization at the single-cell level (early stage
of disease progression; Aim 1) and, second, determine how pathological ECM stiffness drives neointima
formation, altering the local mechanical environment of VSMCs in vitro (advanced stage of disease
progression; Aim 2). Lastly, we will confirm survivin’s role in regulating both ECM production and arterial
stiffness (in vivo animal model; Aim 2). These aims will be achieved using 3D cell culture with a novel
in vitro porcine decellularized aorta ECM-based fibrous scaffold system and mouse injury models. Briefly,
VSMCs isolated from mouse and human aortas will be cultured on nanofibrous scaffolds of different
stiffnesses and structures that mimic normal and pathological conditions in the body. The VSMC
responses to pathological ECM stiffness will be analyzed using advanced microscopy to observe
changes in cellular/nuclear structure and biomechanical properties in vitro, and the RNA and protein
expression will be assessed at the single-cell level. Finally, arterial stiffness and VSMC function will be
studied in intact arteries of injured mice; histology and biochemical analyses of dissected tissues will be
conducted after arterial stiffness has been manipulated by arterial injury, drug treatment, or genetic
mutations. This project will, for the first time, study the molecular and biophysical mechanisms by which
survivin (i) mediates stiffness-sensitive VSMC functions and (ii) contributes to neointima formation and
stiffening, revealing a completely new aspect of survivin biology in VSMCs and in the pathology of
arterial stiffness. Overall, this proposal is unique in its ability to identify potential new therapeutic targets
for the treatment of CVDs.

Grant Number: 5R01HL163168-03
NIH Institute/Center: NIH
Principal Investigator: Yongho Bae