IQGAP1 regulates reactive oxygen species-dependent endothelial cell migration through interacting with Nox2.
OBJECTIVE
Endothelial cell (EC) migration is a key event for repair process after vascular injury and angiogenesis. EC migration is regulated by reorganization of the actin cytoskeleton at the leading edge and localized production of reactive oxygen species (ROS) at the site of injury. However, underlying mechanisms are unclear. We reported that IQGAP1, an actin binding scaffold protein, mediates VEGF-induced activation of gp91phox (Nox2)-dependent NAD(P)H oxidase and EC migration. We thus hypothesized that Nox2 and IQGAP1 may play important roles in ROS-dependent EC migration in response to injury.


RESULTS
Using a monolayer scratch assay with confluent ECs, we show that ROS production is increased at the margin of scratch area and Nox2 translocates to the leading edge, where it colocalizes and associates with both actin and IQGAP1 in migrating ECs. Knockdown of IQGAP1 using siRNA and inhibition of the actin cytoskeleton blocked scratch injury-induced H2O2 production, Nox2 translocation and its interaction with actin, and EC migration toward the injured site.


CONCLUSIONS
These suggest that IQGAP1 may function to link Nox2 to actin at the leading edge, thereby facilitating ROS production at the site of injury, which may contribute to EC migration.
Ikeda
Satoshi
S
Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
Yamaoka-Tojo
Minako
M
Hilenski
Lula
L
Patrushev
Nikolay A
NA
Anwar
Ghulam M
GM
Quinn
Mark T
MT
Ushio-Fukai
Masuko
M
D008841:Actin Cytoskeleton / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000201:enzymology; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000378:metabolism*; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology; D014652:Vascular Diseases / Q000378:metabolism / Q000473:pathology; D020703:ras GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*
C101203:IQ motif containing GTPase activating protein 1; D008562:Membrane Glycoproteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D020703:ras GTPase-Activating Proteins; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases