Constitutive activity of NADPH oxidase 1 (Nox1) that promotes its own activity suppresses the colon epithelial cell migration

Abstract

Superoxide producing NADPH oxidase 1 (Nox1), abundantly expressed in the colon epithelium, plays a crucial role in mucosal host defenses. In this study, we found that pre-treatment of cells with edaravone, a free radical scavenger, inhibited Nox1 constitutive activity even after washout without affecting Nox1 trafficking to the plasma membrane and membrane recruitment of the cytosolic regulators Noxo1 and Noxa1. These results suggest that a Nox1-derived product is involved in the step that initiates the electron transfer reaction after the formation of the Nox1–Noxo1–Noxa1 complex. Furthermore, we show that the mean migration directionality and velocity of epithelial cells were significantly enhanced by the inhibition of constitutive Nox1 activity. Thus, the constitutive Nox1 activity limits undesired cell migration in resting cells while participating in a positive feedback loop toward its own oxidase activity.

Keywords:

• NOX1
• NADPH oxidase
• ROS
• epithelial cells
• cell migration
• edaravone

Acknowledgments

We are grateful to Masumi Itadani (Kawasaki Medical School, Japan) for technical assistance, to the Central Research Institute of Kawasaki Medical School for technical support, and to Minoru Tamura (Ehime University, Japan) for valuable advice.

Disclosure statement

The authors declare that they have no conflicts of interest.

Additional information

Funding

This study was supported in part by JSPS KAKENHI [grant numbers JP17K08637 (KM), JP18K07804 (FK), and JP19K07676 (AY)], in part by the Wesco Scientific Promotion Foundation [grant numbers 2019–2020 (KM) and 2019–2020 (AY)], in part by the Ryobi Teien Memory Foundation [grant numbers 2019 (KM)], and in part by Research Project Grants [grant numbers R01S-003 (KM), H30Y-002 (SO), R01B-081 (FK), and R01B-093 (AY)] from Kawasaki Medical School.