TREM1 and depressive disorder: Quercetin could alleviate LPS-induced depression-like behaviors and impairment of learning and memory, the mechanism of which might be involved with regulating the Brain-derived neurotrophic factor (BDNF)-related imbalance expression of Copine 6 and TREM1/2 in the hippocampus and the prefrontal cortex (PFC) [21].