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Updated: Sep 25, 2025
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Isolation of Pulmonary Artery Smooth Muscle Cells from Neonatal Mice
Published on: October 19, 2013
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DOCK4 Regulation of Rho GTPases Mediates Pulmonary Vascular Barrier Function
Pascal Yazbeck1, Xavier Cullere1, Paul Bennett1
1Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (P.Y., F.C., P.B., H.W., V.M.D., V.M., D.S.M., T.N.M.).
Arteriosclerosis, Thrombosis, and Vascular Biology
|April 28, 2022
Summary
Dedicator of cytokinesis 4 (DOCK4) is crucial for maintaining lung vascular barrier integrity by balancing RhoA and Rac-1 signaling, preventing excessive permeability and hemorrhage.
Area of Science:
- Cell biology
- Vascular biology
- Biochemistry
Background:
- The vascular endothelium regulates fluid and molecule passage between blood and tissues.
- Adherens junctions (AJs), stabilized by VE-cadherin and the actin cytoskeleton, are key to lung vascular barrier integrity.
- Rho GTPases and their guanine exchange factors (GEFs) influence endothelial permeability.
Purpose of the Study:
- To investigate the role of dedicator of cytokinesis 4 (DOCK4), an unconventional Rho GTPase GEF, in vascular function.
- To elucidate DOCK4's mechanism in maintaining lung vascular barrier homeostasis.
Main Methods:
- Generated DOCK4-deficient mice.
- Utilized DOCK4 silencing and reconstitution in human pulmonary artery endothelial cells.
- Assessed protein localization, endothelial cell permeability, and small GTPase activation.
Main Results:
- DOCK4-deficient mice exhibited lung hemorrhage, incomplete smooth muscle cell coverage, increased basal microvascular permeability, and impaired response to S1P.
- DOCK4 absence prevented S1P-induced Rac-1 activation and barrier function enhancement.
- DOCK4-silenced cells showed increased basal permeability linked to Rho GTPase activation.
Conclusions:
- DOCK4 is essential for lung vascular barrier function by balancing RhoA and Rac-1 mediated actin remodeling.
- This study reveals a novel role for atypical GEFs in maintaining vascular integrity.
- Sphingosine-1-phosphate (S1P) may act as an upstream regulator of DOCK4 activity.
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