ROCK Inhibition Reprograms Microglial Polarization to Promote Neuroprotection via NOX2/ROS/TXNIP Suppression

Cerebral ischemia/reperfusion (I/R) injury represents a significant challenge to recanalization therapy for ischemic stroke and is critically influenced by microglial polarization. Although inhibition of Rho-associated protein kinase (ROCK) has been shown to mitigate cerebral I/R injury and associated neuroinflammation, its specific effect on the balance between M1 and M2 (anti-inflammatory) microglial polarization remains incompletely understood. This study aimed to elucidate the role and underlying mechanism of ROCK inhibition in regulating M1 and M2 microglial polarization, using the classical antidepressant fluoxetine as a positive control.

ROCK inhibitor fasudil and positive control fluoxetine effectively alleviated cerebral I/R injury and facilitated a shift in microglial polarization from the M1 to the M2 phenotype, both in vivo and in vitro. In the hippocampal tissues of cerebral I/R mice exposed to lipopolysaccharide, we observed an upregulation of thioredoxin-interacting protein (TXNIP) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2). ROCK2 knockdown promoted the M2 microglial polarization, suppressed the expression of NOX2 and TXNIP, and inhibited the activation of NF-κB P65 in mouse hippocampal tissue. Notably, pharmacological inhibition of NF-κB reduced the expression of NOX2 and TXNIP, as well as the production of reactive oxygen species (ROS), in microglia subjected to oxygen-glucose deprivation/reoxygenation. Correspondingly, inhibition of NOX2 also decreased TXNIP expression.Conclusion and Innovation:ROCK inhibition promotes a shift in microglial polarization from the M1 to the M2 subtype by suppressing the NF-κB/NOX2/ROS/TXNIP signaling pathway. This study provides the first evidence demonstrating the mechanism by which ROCK inhibition drives microglial polarization toward the M2 phenotype. Antioxid. Redox Signal. 45, 149-168.