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GEO help: Mouse over screen elements for information. |
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| Status |
Public on Dec 22, 2014 |
| Title |
Toll-like receptor 2 (TLR2)-TLR9 crosstalk dictates IL-12 family cytokine production in microglia |
| Organism |
Mus musculus |
| Experiment type |
Expression profiling by array
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| Summary |
Microglia are the resident mononuclear phagocytes of the CNS parenchyma and represent an initial line of defense against invading microorganisms. Microglia utilize Toll-like receptors (TLRs) for pathogen recognition and TLR2 specifically senses conserved motifs of gram-positive bacteria including lipoproteins, lipoteichoic acids, and peptidoglycan (PGN) leading to cytokine/chemokine production. Interestingly, primary microglia derived from TLR2 knockout (KO) mice over-expressed numerous IL-12 family members, including IL-12p40, IL-12p70, and IL-27 in response to intact S. aureus, but not the less structurally complex TLR2 ligands Pam3CSK4 or PGN. The ability of intact bacteria to augment IL-12 family member expression was specific for gram-positive organisms, since numerous gram-negative strains were unable to elicit exaggerated responses in TLR2 KO microglia. Inhibition of SYK or IRAK4 signaling did not impact heightened IL-12 family member production in S. aureus-treated TLR2 KO microglia, whereas PI3K, MAPK, and JNK inhibitors were all capable of restoring exaggerated cytokine expression to wild type levels. Additionally, elevated IL-12 production in TLR2 KO microglia was ablated by a TLR9 antagonist, suggesting that TLR9 drives IL-12 family member production following exposure to intact bacteria that remains unchecked in the absence of TLR2 signaling. Collectively, these findings indicate crosstalk between TLR2 and TLR9 pathways to regulate IL-12 family member production by microglia. The summation of TLR signals must be tightly controlled to ensure the timely cessation and/or fine tuning of cytokine signaling to avoid nonspecific bystander damage due to sustained IL-12 release.
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| Overall design |
TLR2 KO mice were backcrossed with C57BL/6 animals for a minimum of eight generations prior to use in these studies. Age- and sex-matched C57BL/6 mice were used as wild type (WT) controls. Primary mixed glial cultures were prepared from the cerebral corticies of neonatal mice (2-4 days of age) and microglia were harvested using a differential shaking technique with a purity of >98%. A USA300 community-acquired methicillin-resistant S. aureus (CA-MRSA) clinical isolate recovered from a patient with a fatal brain abscess was used to stimulate the microglia isolates. Bacterial strains were heat-inactivated and used to stimulate microglia at 107 colony forming units (cfu)/well for 6 and 12 hours time points. Three replicates of each mouse type (WT, TLR2 KO) at both time points 6 and 12 hours were used for the microarray experiments. Data was only usable for 2 replicates of the KO-12 hr group.
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| Contributor(s) |
Holley MM, Zhang Y, Lehrmann E, Wood WH, Becker KG, Kielian T |
| Citation(s) |
21901759 |
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| Submission date |
Oct 26, 2010 |
| Last update date |
Jun 22, 2020 |
| Contact name |
Supriyo De |
| Organization name |
NIA-IRP, NIH
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| Department |
Laboratory of Genetics and Genomics
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| Lab |
Computational Biology & Genomics Core
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| Street address |
251 Bayview Blvd
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| City |
Baltimore |
| State/province |
Maryland |
| ZIP/Postal code |
21224 |
| Country |
USA |
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| Platforms (1) |
| GPL6885 |
Illumina MouseRef-8 v2.0 expression beadchip |
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| Samples (11)
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| Relations |
| BioProject |
PRJNA131929 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE24935_RAW.tar |
3.1 Mb |
(http)(custom) |
TAR |
| GSE24935_non-normalized_data.txt.gz |
5.1 Mb |
(ftp)(http) |
TXT |
| Processed data included within Sample table |
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