| Title: | Depression and interleukin-6 signaling: A Mendelian Randomization study |
| Journal: | Brain Behavior and Immunity |
| Published: | 23 Feb 2021 |
| Pubmed: | https://pubmed.ncbi.nlm.nih.gov/33631287/ |
| DOI: | https://doi.org/10.1016/j.bbi.2021.02.019 |
Publication 4642
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Abstract
BACKGROUND: A large body of research has reported associations between depression and elevated interleukin-6 (IL-6), a cytokine with several roles including pro-inflammatory signaling. The nature and directionality of this relationship are not yet clear. In this study we use Mendelian Randomization to examine the possibility of a causal relationship between IL-6 and depressive symptoms, and to explore multiple signaling pathways that could serve as mechanisms for this relationship.</p>
METHODS: This study uses a two-sample Mendelian Randomization design. Data come from the UK Biobank (n = 89,119) and published summary statistics from six existing GWAS analyses. The primary analysis focuses on the soluble interleukin-6 receptor (sIL-6R), which is involved in multiple signaling pathways. Exploratory analyses use C-reactive protein (CRP) and soluble glycoprotein 130 (sgp130) to further examine potential underlying mechanisms.</p>
RESULTS: Results are consistent with a causal effect of sIL-6R on depression (PCA-IVW Odds Ratio: 1.023 (95% Confidence Interval: 1.006-1.039), p = 0.006). Exploratory analyses demonstrate that the relationship could be consistent with either decreased classical signaling or increased trans signaling as the underlying mechanism.</p>
DISCUSSION: These results strengthen the body evidence implicating IL-6 signaling in depression. When compared with existing observational and animal findings, the direction of these results suggests involvement of IL-6 trans signaling. Further study is needed to examine whether IL6R genetic variants might influence IL-6 trans signaling in the brain, as well as to explore other potential pathways linking depression and inflammation.</p>
6 Keywords
- Animals
- Cytokine Receptor gp130
- Depression
- Interleukin-6
- Mendelian Randomization Analysis
- Receptors, Interleukin-6
3 Authors
- Kristen M Kelly
- Jennifer A Smith
- Briana Mezuk
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