Systems Pharmacology-based Investigation Of Active Ingredients Of Lonicerae Japonicae Flos Uncover Its Psychotherapeutic Effects And Methylglyoxal Mediated Pathogenic Mechanisms Of Depression

Psychiatric disorders,particularly depressive disorders,have become the biggest cause of non-fatal health burden and are the major contributor to suicide worldwide.Despite massive efforts,unravelling the pathophysiology of depressive disorders and developing effective treatments is still a huge challenge.The currently limitations of standard psychotherapy lead to an increasing attention in complementary and alternative therapies,in particular the traditional herbal medicine.Nowadays,Lonicerae Japonicae Flos(LJF),like most herbal teas with reputed therapeutic value,has widespread acceptance as a consumption beverage,whereas its therapeutic value is criticized for a lack of empirical research,yet have not reached acceptance by mainstream medicine.Therefore,the development of new strategies for the screening of natural products in herbal medicines and the discovery of novel antidepressant mechanism are imminent.In this study,combined our previously established systems pharmacology strategy with RNA-Seq technology,we uncovered psychotherapeutic effects of LJF and screened out luteolin as an natural drug for depression therapy.To proceed,we found the anti-depressants effects of LUT is achieved by its direct binding to Glyoxalase 1(GLO1),which lead to an increase in Methylglyoxal(MGO)concentration.Further studies revealed that MGO binds to the extracellular domain of Trk B and provokes its dimerization and autophosphorylation,which then activates the downstream Akt and ERK signaling,as well as the phosphorylation of the transcription factor CREB.This effectively induces the expression of BDNF and forms a BDNF-positive feedback loop,which further promotes the synaptic plasticity of nerons.The major conclusions are summarized as follows:(1)After ADME filtering,a set of 16 ingredients with promising pharmacokinetic properties was screened out from LJF.The C-T analysis showed that these candidate active compounds of LJF probably act on 298 target proteins.Either compounds or targets in the network displayed polypharmacology properties,indicating therapeutic polypharmacology and synergism in LJF treatment.Disease association analysis identified 144 targets of LJF have psychotherapeutic activity,these targets and 55 significantly enriched pathways formed the T-P pathways,which provided the observations that psychotherapeutic effects of LJF may mainly through the modulation of the serotonergic synapse,c AMP signaling and neuroactive ligandreceptor interaction pathways.(2)Animal behavior assessments evaluated the anti-depression and anxiety effects of LJF and LUT with two behavioral tests for CMS model.RNA-Seq analysis of rat striatum confirmed that the treatment with LJF and LUT reversed the global changes induced by chronic mild stress.Pathway enrichment analysis of differentially expressed genes(DEGs)was coincident with the prediction that psychiatric disorderrelevant targets of LJF were most enriched in serotonergic synapse pathway.Biology processes such as cell survival and apoptosis were mostly affected,the presence of these findings can be explained by modulation of ion channel activity,receptor function and neurotransmitter release,as well as activation of downstream cascade.Biochemistry and molecular biology experiments supported the speculation that LJF and LUT treatment can effectively restored neurotransmission,and reversed abnormal expression of genes involving apoptosis process,these effects may be through triggering the activation of the HTR2A/PLCγ/ERK/CREB pathway.(3)The anti-depressant effects of LUT is achieved by its direct binding to Glyoxalase 1(GLO1),which lead to an increase in MGO concentration in PC12 cells.Further study showed that MGO levels are remarkedly decreased in the prefrontal cortex(PFC),hippocampus(HC)and also plasma in rats subjected to chronic stress,whereas low-dose MGO treatment remarkedly enhances resilience to stress and alleviates depression-like symptoms.Besides,MGO also effectively promotes the synaptic plasticity in PFC and the hippocampal neurogenesis in CMS rats,and thus presents antidepressant-like effects.(4)Incubation of MGO with PC12 cells for 1 h produced a concentrationdependent activation of the BDNF-Trk B signaling pathway.Additionally,MGO showed fast and long lasting activation of the BDNF-Trk B signaling.Further,silencing of GLO1 in PC12 cells increased the levels of p-Trk B,p-Akt,p-ERK1/2 and p-CREB,as well as the expression levels of BDNF protein and its m RNA.Reciprocally,the overexpression of GLO1 in PC12 cells significantly increased both the protein and m RNA levels of GLO1,along with decreased MGO levels.The activation of MGO on BDNF-Trk B signaling is achieved by MGO’s direct binding to the extracellular domain(ECD)of Trk B to stimulate its dimerization and autophosphorylation.This enables MGO to switch on the Trk B signaling pathways,which leads to a rapid and sustained expression of BDNF.