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Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
NOD2 regulates microglial inflammation through the TAK1-NF-κB pathway and autophagy activation in murine pneumococcal
Guan Wang1, Yanan Fu2, Kun Ma3
1Department of Pediatrics, Qilu Hospital, Shandong University, 107#, Wen Hua Xi Road, Jinan, Shandong, 250012, PR China.
Abstract:
Streptococcus pneumoniae is responsible for pneumococcal meningitis, with significant mortality and morbidity worldwide. Microglial inflammation plays a vital role in meningitis. The peptidoglycan sensor NOD2 (nucleotide-binding oligomerization domain 2) has been identified to promote microglia activation, but the role in autophagy following pneumococcal meningitis remains unclear. In the present study, we investigated the role of NOD2 in microglial inflammation and autophagy, as well as related signaling pathways, during S. pneumonia infection. NOD2 expression was knocked down by the injection of lentivirus-mediated short-hairpin RNA (shRNA). Our results revealed that NOD2 promotes microglial inflammation by increasing inflammatory mediators. We also showed that the TAK1-NF-κB pathway is involved in this process. In addition, NOD2 increased the expression of autophagy-related proteins and induced autophagosome formation. Rapamycin and 3-MA were utilized to assess the role of autophagy in microglial inflammation induced by S. pneumonia. We demonstrated that autophagy serves as a cellular defense mechanism to reduce inflammatory mediators. Similar to the in vitro results, NOD2 induced inflammation and autophagy in the brain in a mouse meningitis model. Moreover, NOD2 silencing significantly reduced brain edema and improved the neurological function of pneumococcal meningitis mice. Taken together, these data demonstrate that NOD2 promotes microglial inflammation and autophagy in murine pneumococcal meningitis, and the TAK1-NF-κB pathway is involved in microglial activation.
Insights
Nucleotide-binding oligomerization domain 2 (NOD2) promotes microglial inflammation and autophagy in pneumococcal meningitis. Silencing NOD2 reduces brain edema and improves neurological function, highlighting its therapeutic potential.
Area of Science:
- Neuroscience
- Immunology
- Microbiology
Background:
- Pneumococcal meningitis, caused by Streptococcus pneumoniae, leads to high mortality and morbidity globally.
- Microglial inflammation is a key factor in meningitis pathogenesis.
- The role of nucleotide-binding oligomerization domain 2 (NOD2) in microglial autophagy during pneumococcal meningitis is not well understood.
Purpose of the Study:
- To investigate the role of NOD2 in microglial inflammation and autophagy in pneumococcal meningitis.
- To elucidate the signaling pathways involved in NOD2-mediated microglial activation.
- To assess the therapeutic potential of targeting NOD2 in a murine meningitis model.
Main Methods:
- NOD2 expression was suppressed using lentivirus-mediated short-hairpin RNA (shRNA) in vitro and in vivo.
- Inflammatory mediators and autophagy-related proteins were quantified.
- Autophagosome formation was observed.
- The TAK1-NF-κB pathway was analyzed.
- Pharmacological agents (Rapamycin, 3-MA) were used to modulate autophagy.
- Neurological function and brain edema were assessed in a mouse model of pneumococcal meningitis.
Main Results:
- NOD2 significantly increased inflammatory mediators and promoted microglial activation via the TAK1-NF-κB pathway.
- NOD2 enhanced the expression of autophagy-related proteins and induced autophagosome formation.
- Autophagy acted as a cellular defense mechanism, reducing inflammatory mediators.
- NOD2 silencing in a mouse model reduced brain edema and improved neurological outcomes.
Conclusions:
- NOD2 plays a critical role in promoting microglial inflammation and autophagy during murine pneumococcal meningitis.
- The TAK1-NF-κB pathway is implicated in NOD2-mediated microglial activation.
- Targeting NOD2 may offer a therapeutic strategy for reducing meningitis-associated brain damage and neurological deficits.
