Toll-Like Receptor 9 Is Required for Chronic Stress-Induced Immune Suppression
Document Type
Article
Publication Date
12-1-2013
Description
Objectives: Mental and physical stress can suppress the immune system in both humans and animals. The mechanism by which stress affects immune responses, however, remains poorly defined. Toll-like receptors (TLRs) play a key role in modulating immune responses and cell survival. The mechanisms by which TLRs modulate chronic stress are largely unexplored. Methods: Six- to 8-week-old male mice were subjected to chronic 12-hour daily physical restraint stress. Apoptotic cells were determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. We examined cytokine levels by enzyme-linked immunosorbent Assay (ELISA). The expression of CYP11A1 was determined by quantitative real-time RT-PCR. Results: TLR9-deficient mice were resistant to chronic stress-induced lymphocyte apoptosis. In addition, in TLR9 knockout (KO) mice, chronic stress-induced upregulation of corticosterone levels was significantly decreased. Notably, lymphocytes from both TLR9 KO and wild-type mice were similarly sensitive to corticosteroid-induced cell apoptosis. Moreover, TLR9 deficiency blocked the chronic stress-induced imbalance in T helper (Th) 1 and Th2 cytokine levels. Conclusion: Taken together, our findings reveal that TLR9 plays an essential role in chronic stress-induced immune suppression.
Citation Information
Li, Hui; Zhao, Jing; Chen, Michael; Tan, Yang; Yang, Xiaohua; Caudle, Yi; and Yin, Deling. 2013. Toll-Like Receptor 9 Is Required for Chronic Stress-Induced Immune Suppression. NeuroImmunoModulation. Vol.21(1). 1-7. https://doi.org/10.1159/000354610 PMID: 24080854 ISSN: 1021-7401