[P3-41] Everolimus is better than rapamycin in attenuating neuroinflammation in kainic acid-induced seizures
Background: Microglia is responsible for neuroinflammation, which may aggravate brain injury in diseases like epilepsy. Mammalian target of rapamycin (mTOR) kinase is related to microglial activation with subsequent neuroinflammation. In the present study, rapamycin and everolimus, both as mTOR inhibitors, were investigated in models of kainic acid (KA)-induced seizure and lipopolysaccharide (LPS)-induced neuroinflammation.
Methods: In vitro, we treated BV2 cells with KA and LPS. In vivo, KA was used to induce seizures on postnatal day 25 in B6.129P-Cx3cr1tm1Litt/J mice. Rapamycin and everolimus were evaluated in their modulation of neuroinflammation detected by real-time PCR, western blotting, and immunostaining.
Results: Everolimus was significantly more effective than rapamycin in inhibiting iNOS and mTOR signaling pathways in both models of neuroinflammation (LPS) and epilepsy (KA). Everolimus attenuated the iNOS mRNA expression by LPS and nitrite production by KA and LPS more significantly than rapamycin. Only everolimus attenuated the mTOR mRNA expression by LPS and KA treatment. In the present study, we also found that the modulation of mTOR under LPS and KA treatment was not mediated by Akt pathway, but was mainly mediated by ERK phosphorylation, which was attenuated more significantly by everolimus. This inhibition of ERK phosphorylation and microglial activation in hippocampus by everolimus was also confirmed in KA-treated rats.
Conclusions: Rapamycin and everolimus can block the activation of inflammation-related molecules, and attenuated the microglia activation. Everolimus had better efficacy than rapamycin, possibly mediated by inhibition of ERK phosphorylation. Taken together, mTOR inhibitor can be a potential pharmacological target of anti-inflammation and epilepsy treatment.
Methods: In vitro, we treated BV2 cells with KA and LPS. In vivo, KA was used to induce seizures on postnatal day 25 in B6.129P-Cx3cr1tm1Litt/J mice. Rapamycin and everolimus were evaluated in their modulation of neuroinflammation detected by real-time PCR, western blotting, and immunostaining.
Results: Everolimus was significantly more effective than rapamycin in inhibiting iNOS and mTOR signaling pathways in both models of neuroinflammation (LPS) and epilepsy (KA). Everolimus attenuated the iNOS mRNA expression by LPS and nitrite production by KA and LPS more significantly than rapamycin. Only everolimus attenuated the mTOR mRNA expression by LPS and KA treatment. In the present study, we also found that the modulation of mTOR under LPS and KA treatment was not mediated by Akt pathway, but was mainly mediated by ERK phosphorylation, which was attenuated more significantly by everolimus. This inhibition of ERK phosphorylation and microglial activation in hippocampus by everolimus was also confirmed in KA-treated rats.
Conclusions: Rapamycin and everolimus can block the activation of inflammation-related molecules, and attenuated the microglia activation. Everolimus had better efficacy than rapamycin, possibly mediated by inhibition of ERK phosphorylation. Taken together, mTOR inhibitor can be a potential pharmacological target of anti-inflammation and epilepsy treatment.