Trilobatin, a naturally occurring GPR158 ligand, alleviates depressive-like behavior by promoting mitophagy

Abstract Background and Purpose: G-protein-coupled receptor (GPR158), an orphan receptor, is highly expressed in the medial prefrontal cortex in (mPFC) and identified as a novel therapeutic target for treating depression. Trilobatin (TLB) is a naturally-occurring food additive with potent neuroprotective properties. However, its pharmacological effects and molecular mechanisms against depression remains unknown. We explored whether TLB alleviates depression by targeting GPR158. Experimental Approach: Chronic unpredictable mild stress (CUMS)-induced depression mice model was used to explore antidepressant-like effect of TLB. GPR158-deficent mice were treated with TLB to determine whether TLB exerts its antidepressant-like effect by targeting GPR158. Key Results: TLB effectively alleviated CUMS-induced depressive-like behavior in mice. Mitophagy was contributed to the antidepressant-like effect of TLB, as evidenced by qRT-PCR array. As anticipated, TLB up-regulated autophagy associated protein expression of PFC in mice and restored mitochondrial dynamic balance, further inhibiting oxidative stress, as reflected by reducing ROS generation and increasing antioxidant enzymes. Mechanistically, GPR158 deficiency also up-regulated autophagy associated proteins expression and rejuvenated mitochondrial dynamic, further attenuating depressive-like behavior in response to CUMS insult. Most importantly, TLB directly bound to GPR158 and decreased its protein expression. Encouragingly, the promotive effect of TLB on mitophagy and its antidepressant-like effect were enhanced in GPR158-deficent mice. Conclusions and Implications: Our findings not only highlight GPR158-mediated mitophagy as a crucial pharmacological target for managing depression, but also reveal a new-found pharmacological property of TLB: serving as a novel naturally-occurring ligand of GPR158 to safeguard depression from oxidative stress by promoting mitophagy.