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Proc Natl Acad Sci U S A. 2017 Aug 15;114(33):8758-8763. doi: 10.1073/pnas.1618333114. Epub 2017 Aug 1.

Three-dimensional biomimetic vascular model reveals a RhoA, Rac1, and N-cadherin balance in mural cell-endothelial cell-regulated barrier function.

Author information

1
Department of Biomedical Engineering, Boston University, Boston, MA 02215.
2
Biological Design Center, Boston University, Boston, MA 02215.
3
The Wyss Institute for Biologically Inspired Engineering at Harvard, Harvard University, Boston, MA 02115.
4
Department of Science, Mount St. Mary's University, Emmitsburg, MD 21727.
5
Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98195.
6
Department of Pathology, University of Washington, Seattle, WA 98195.
7
Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195.
8
Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA 19104.
9
Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104.
10
Department of Biomedical Engineering, Boston University, Boston, MA 02215; chencs@bu.edu.

Abstract

The integrity of the endothelial barrier between circulating blood and tissue is important for blood vessel function and, ultimately, for organ homeostasis. Here, we developed a vessel-on-a-chip with perfused endothelialized channels lined with human bone marrow stromal cells, which adopt a mural cell-like phenotype that recapitulates barrier function of the vasculature. In this model, barrier function is compromised upon exposure to inflammatory factors such as LPS, thrombin, and TNFα, as has been observed in vivo. Interestingly, we observed a rapid physical withdrawal of mural cells from the endothelium that was accompanied by an inhibition of endogenous Rac1 activity and increase in RhoA activity in the mural cells themselves upon inflammation. Using a system to chemically induce activity in exogenously expressed Rac1 or RhoA within minutes of stimulation, we demonstrated RhoA activation induced loss of mural cell coverage on the endothelium and reduced endothelial barrier function, and this effect was abrogated when Rac1 was simultaneously activated. We further showed that N-cadherin expression in mural cells plays a key role in barrier function, as CRISPR-mediated knockout of N-cadherin in the mural cells led to loss of barrier function, and overexpression of N-cadherin in CHO cells promoted barrier function. In summary, this bicellular model demonstrates the continuous and rapid modulation of adhesive interactions between endothelial and mural cells and its impact on vascular barrier function and highlights an in vitro platform to study the biology of perivascular-endothelial interactions.

KEYWORDS:

3D culture; N-cadherin; RhoGTPases; mural cells; vascular inflammation

PMID:
28765370
PMCID:
PMC5565405
DOI:
10.1073/pnas.1618333114
[Indexed for MEDLINE]
Free PMC Article

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