TLR9 activation via microglial glucocorticoid receptors contributes to degeneration of midbrain dopamine neurons.
Layal MaatoukAnne-Claire CompagnionMaria-Angeles Carrillo-de SauvageAlexis Pierre BemelmansSabrina Leclere-TurbantVincent CirotteauMira TohmeAllen BekeMichaël TrichetVirginie BazinBobby N TrawickRichard M RansohoffFrançois TroncheBénédicte ManourySheela VyasPublished in: Nature communications (2018)
Inflammation is a characteristic feature of Parkinson's disease (PD). We examined the role of TLR9 and its regulation by glucocorticoid receptors (GRs) in degeneration of substantia nigra dopamine neurons (DNs). TLR9 agonist, CpG-ODN, induced DN degeneration in mice lacking GR in microglia but not in controls. TLR9 deletion reduced DN loss in neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. GR regulates TLR9 activation during MPTP neurotoxicity as TLR9 antagonist suppressed increased DN loss in microglia/macrophage GR mutant mice. GR absence in microglia enhanced TLR9 translocation to endolysosomes and facilitated its cleavage leading to pro-inflammatory gene expression. GR-dependent TLR9 activation also triggered DN loss following intranigral injection of mitochondrial DNA. Finally, microglial GR sensitivity to A53T-alpha-synuclein induced DN degeneration as well as decreased microglial GR expression observed in SN of PD brain samples, all suggest that reduced microglial GR activity in SN can stimulate TLR9 activation and DN loss in PD pathology.
Keyphrases
- inflammatory response
- toll like receptor
- lipopolysaccharide induced
- lps induced
- immune response
- gene expression
- mitochondrial dna
- neuropathic pain
- nuclear factor
- mouse model
- dna methylation
- machine learning
- spinal cord
- copy number
- metabolic syndrome
- multiple sclerosis
- binding protein
- spinal cord injury
- drug induced
- white matter
- deep learning