A pro-inflammatory mediator USP11 enhances the stability of p53 and inhibits KLF2 in intracerebral hemorrhage

Microglial cell activation and neuroinflammation after intracerebral hemorrhage (ICH) lead to secondary brain damage. Ubiquitin-specific protease 11 (USP11) has been correlated with ICH-induced neuron apoptosis. This study aims to explore the molecular mechanism of USP11 regulating neuroinflammation in ICH. First, an ICH rat model was developed by intracranial administration of collagenase. Silencing USP11 was found to alleviate nerve injury in rats with ICH-like symptoms. Then, through loss- and gain-of-function assays, USP11 knockdown was revealed to alleviate ICH-induced symptoms, corresponding to reduced modified neurological severity scores (mNSS) value, brain water content, blood-brain barrier permeability, neuron apoptosis, microglial cell activation, neutrophil infiltration, and inflammatory factor secretion. It was subsequently shown in microglial cells that USP11 stabilized p53 by deubiquitination and p53 targeted the Kruppel-like factor 2 (KLF2) promoter to repress KLF2 transcription, thereby activating the nuclear factor κB (NF-κB) pathway. Further, rescue experiments were conducted in vivo to validate the function of the USP11/p53/KLF2/NF-κB axis in ICH-induced inflammation, which confirmed that USP11 silencing blocked the release of pro-inflammatory cytokines following ICH by downregulating p53, thus protecting against neurological impairment. Hence silencing USP11 may be a novel anti-inflammatory method for ICH treatment.