Mechanisms of endothelial cell dysfunction in cystic fibrosis

https://doi.org/10.1016/j.bbadis.2017.08.011Get rights and content
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Highlights

  • CFTR-loss-of-function impairs endothelial monolayer integrity.

  • Changes in VE-cadherin and p120 catenin expression are involved.

  • CF endothelial cells release an increased number of dysfunctional microvesicles.

  • CFTR-loss-of-function impairs eNOS function.

  • cAMP-increasing drugs exert protective actions.

Abstract

Although cystic fibrosis (CF) patients exhibit signs of endothelial perturbation, the functions of the cystic fibrosis conductance regulator (CFTR) in vascular endothelial cells (EC) are poorly defined. We sought to uncover biological activities of endothelial CFTR, relevant for vascular homeostasis and inflammation. We examined cells from human umbilical cords (HUVEC) and pulmonary artery isolated from non-cystic fibrosis (PAEC) and CF human lungs (CF-PAEC), under static conditions or physiological shear. CFTR activity, clearly detected in HUVEC and PAEC, was markedly reduced in CF-PAEC. CFTR blockade increased endothelial permeability to macromolecules and reduced trans‑endothelial electrical resistance (TEER). Consistent with this, CF-PAEC displayed lower TEER compared to PAEC. Under shear, CFTR blockade reduced VE-cadherin and p120 catenin membrane expression and triggered the formation of paxillin- and vinculin-enriched membrane blebs that evolved in shrinking of the cell body and disruption of cell-cell contacts. These changes were accompanied by enhanced release of microvesicles, which displayed reduced capability to stimulate proliferation in recipient EC. CFTR blockade also suppressed insulin-induced NO generation by EC, likely by inhibiting eNOS and AKT phosphorylation, whereas it enhanced IL-8 release. Remarkably, phosphodiesterase inhibitors in combination with a β2 adrenergic receptor agonist corrected functional and morphological changes triggered by CFTR dysfunction in EC. Our results uncover regulatory functions of CFTR in EC, suggesting a physiological role of CFTR in the maintenance EC homeostasis and its involvement in pathogenetic aspects of CF. Moreover, our findings open avenues for novel pharmacology to control endothelial dysfunction and its consequences in CF.

Abbreviations

AJ
adherent junctions
CFTR
cystic fibrosis conductance regulator
ECGF
endothelial cell growth factor
EMV
endothelial microvesicles
eNOS
endothelial nitric oxide synthase
HUVEC
human umbilical vein endothelial cells
PAEC
pulmonary artery endothelial cells
PDE
phosphodiesterase
PKA
protein kinase A
TEER
trans‑endothelial electrical resistance
TNF-α
tumor necrosis factor-α
YFP
yellow fluorescent protein

Keywords

Cystic fibrosis
Endothelial cells
Inflammation
Nitric oxide
Microvesicles
Cyclic AMP

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