These observations demonstrate that IL6 directly controls SERT levels and consequently serotonin reuptake and identify STAT3-dependent regulation of SERT as conceivable neurobiological substrate for the involvement of IL6 in depression.
However, the expression of DNMT1/3A, EZH2 and IL-6 genes increases with increasing Hospital Anxiety and Depression Scale-Anxiety scores in the anxious cohort only.
Changes in the mRNA expression of inflammatory cytokines, including interleukin (IL)-1β, tumor necrosis factor-α, IL-6, and interferon-γ, were not correlated with the decrease in hippocampal neurogenesis or the appearance of depression-like behavior during the chronic phase following irradiation.
These results suggest that the plasma levels of IL-6 reflect the severity of MDD and that plasma IL-6 levels might be another biological-state marker for the depressive state.