Gp91phox (NOX2) in classically activated microglia exacerbates traumatic brain injury

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Traumatic brain injury (TBI) is associated with oxidative stress.
• gp91phox (NOX2), a subunit of NADPH oxidase, generates superoxide anion (O2-) and is implicated in TBI pathogenesis.

Purpose of the Study:

• To investigate the role of gp91phox and reactive oxygen species (ROS) in TBI.
• To determine the microglial phenotype responsible for gp91phox generation after TBI.

Main Methods:

• Controlled cortical impact TBI was induced in gp91phox knockout and wild-type mice.
• gp91phox expression and its role in TBI were analyzed using immunoblotting and staining.
• Levels of O2- and peroxynitrite were measured in brain tissue.
• Microglial activation and gp91phox expression were studied in BV-2 cells stimulated with IFNgamma or IL-4.

Main Results:

• gp91phox expression was elevated in activated microglia in wild-type mice post-TBI.
• gp91phox knockout mice exhibited reduced brain damage, cell death, and oxidative stress markers compared to wild-type mice.
• IFNgamma stimulation induced a classical activated microglial phenotype with increased gp91phox expression and nitric oxide production.

Conclusions:

• Classically activated microglia contribute to TBI-induced brain damage via gp91phox-mediated ROS production.
• Targeting gp91phox and its downstream ROS may represent a novel therapeutic approach for TBI.