Edaravone Plays Protective Effects on LPS-Induced Microglia by Switching M1/M2 Phenotypes and Regulating NLRP3 Inflammasome Activation

Abstract

Parkinson’s disease is a neurodegenerative disorder in which activated microglia may appear prior to motor symptoms, but the specific therapeutic mechanisms remain unclear. This study investigated the potential effects of Edaravone (EDA) on M1/M2 polarization of microglia in rats with dopaminergic neurons damage induced by lipopolysaccharide (LPS) and its mechanism. Rats were randomly grouped as the following (n = 10): Control, EDA alone (10 mg/kg), LPS-model (LPS 5 μg), LPS + EDA (5 mg/kg) and LPS + EDA (10 mg/kg). After intragastric administration of EDA once a day for seven consecutive days, LPS was injected into SN pars unilaterally. Rotarod test, pole test, and traction test were used to analyze the intervention effect of EDA on neurobehavioral function in rats. Protein expression levels of TH, TNF-α, Arg-1, Iba-1, NLRP3 and caspase-1 were measured by immunofluorescence staining and western blot. In vitro, BV-2 cells were treated with LPS (100 ng/ml) before adding different doses of EDA. Levels of inflammatory cytokines in culture medium were detected by ELISA. Western blot and immunofluorescence were used to evaluate microglial activation and polarization. First, rotarod test, pole test, and traction test all showed that EDA mitigated motor dysfunction of PD rats. Second, pathological analysis suggested that EDA inhibited LPS-induced microglial activation and remitted declines of dopaminergic neurons. In addition, EDA shifted M1 pro-inflammatory phenotype of microglia to M2 anti-inflammatory state, while decreased expression of M1 markers (TNF-α and IL-1β) and facilitated expression of M2 markers (Arg-1 and IL-10). EDA suppressed inflammatory responses through inhibiting the expression of pro-inflammatory factors (IL-1β, IL-18 and NO), but the neuroprotective effects were invalid while siRNA NLRP3 existed. In conclusion, these results indicated that EDA could improve neurobehavioral functions and play anti-neuroinflammatory roles in PD rats, possibly by inhibiting NLPR3 inflammasome activation and regulating microglia M1/M2 polarization.

TJ-M2010-5, a novel CNS drug candidate, attenuates acute cerebral ischemia-reperfusion injury through the MyD88/NF-κB and ERK pathway

“…Considering that MyD88 activation may enhance neuroinflammation caused by ischemic stroke, we hypothesized that TJ-5 might potently inhibit neuroinflammation to protect against CIRI ( Figures 8A, B ). In CIRI mice model, we compared the neuroprotective effects of edaravone, a medicine currently used clinically for the treatment of ischemic stroke ( Li et al, 2021 ), and different concentrations of TJ-5. We found that TJ-5 at 15 mg/kg was more effective, as the infarction volume was reduced by approximately 80%, achieving better neuroprotective effects than edaravone.…”

“…BV-2 microglial and SH-SY5Y cells were cultured as previously described ( Zhao et al, 2020 ). A lipopolysaccharide (LPS)-stimulated BV-2 cell model was established to mimic severe neuroinflammation induced by multiple inflammatory mediators after reperfusion ( Li et al, 2021 ). BV-2 cells were pretreated with different concentrations of TJ-5 for 2 h before LPS (1 μg/ml) stimulation (#L2880, Sigma, United States).…”

Edaravone dexborneol alleviates cerebral ischemia‐reperfusion injury through NF‐κB/NLRP3 signal pathway

“…The Iba‐1 was used as a marker for positive microglia. The polarization of microglia cells was marked by separate antibodies, nitric oxide synthase (iNOS) for M1 microglia and Arg1 (Arginase‐1) for M2 microglia (Li, Dai, et al, 2021; Zhou et al, 2021). Briefly, all selected brain slices were incubated with different antibodies overnight at 4°C, including Iba‐1 (Abcam, 1:500), iNOS (Proteintech, 1:500), Arg1 (Proteintech, 1:500), NLRP3 (Affinity, 1:200) and NF‐κB p65 (Affinity, 1:200).…”

The Translational Potential of Microglia and Monocyte-Derived Macrophages in Ischemic Stroke

“…Montelukast acts as an antagonist of the CysLT-1 receptor and has been found to increase the number of M2 phenotype microglia during the acute phase of stroke ( 155 ). Edaravone is a free radical scavenger used in the treatment of amyotrophic lateral sclerosis (ALS), which has been found to promote the M2 microglia activation in preclinical studies ( 160 , 167 ). In a retrospective study by Enomoto et al, clinical outcomes of patients who underwent endovascular reperfusion therapy and edavarone therapy within two days of admission were compared with patients who underwent endovascular reperfusion alone.…”