Search bioRxiv⌕ Search

Biology subjects

Shelton, S. E.

Publications and source records attributed to Shelton, S. E..

2 recordsLinked to original sources

Myofibroblasts reduce angiogenesis and vasculogenesis in a vascularized microphysiological model of lung fibrosis

Lung fibrosis, characterized by chronic and progressive scarring, has no cure. Hallmarks are the accumulation of myofibroblasts and extracellular matrix, as well as vascular remodeling. The crosstalk between myofibroblasts and vasculature is poorly understood, with conflicting reports on whether angiogenesis and vessel density are increased or decreased in lung fibrosis. We developed a microphysiological system that recapitulates the pathophysiology of lung fibrosis and disentangles myofibroblast-vascular interactions. Lung myofibroblasts maintained their phenotype in 3D without exogenous TGF-{beta} and displayed anti-angiogenic and anti-vasculogenic activities when cultured with endothelial cells in a microfluidic device. These effects, including decreased endothelial sprouting, altered vascular morphology, and increased vascular permeability, were mediated by increased TGF-{beta}1 and reduced VEGF secretion. Pharmacological interventions targeting these cytokines restored vascular morphology and permeability, demonstrating the potential of this model to screen anti-fibrotic drugs. This system provides insights into myofibroblast-vascular crosstalk in lung fibrosis and offers a platform for therapeutic development.

bioengineering↗

Engineering microvascular networks using a KLF2 reporter to probe flow-dependent endothelial cell function

Shear stress generated by the flow of blood in the vasculature is a potent regulator of endothelial cell phenotype and vascular structure. While vascular responses to flow are complex and context-dependent, endothelial cell signaling in response to shear stress induced by laminar flows is coordinated by the transcription factor KLF2. The expression of KLF2 in endothelial cells is associated with a quiescent, anti-inflammatory phenotype and has been well characterized in two-dimensional systems, but has not been studied in three-dimensional in vitro systems. Here we develop engineered microvascular networks (MVNs) with a KLF2-based endothelial cell sensor within a microfluidic chip, apply continuous flow using an attached microfluidic pump, and study the effects of this flow on vascular structure and function. We found that culture of MVNs exposed to flow for 48 hours that resulted in increased expression of the KLF2-GFP-reporter display larger vessel diameters and decreased vascular branching and resistance. Additionally, vessel diameters after the application of flow were independent of initial MVN morphologies. Finally, we found that MVNs exposed to flow have improved vascular barrier function and decreased platelet adhesion. The MVNs with KLF2-based flow sensors represent a powerful tool for evaluating the structural and functional effects of flow on engineered three-dimensional vascular systems.

bioengineering↗