Predicting a Potential Link to Antidepressant Effect: Neuroprotection of Zhi-zi-chi Decoction on Glutamate-induced Cytotoxicity in PC12 Cells

Zhi-zi-chi decoction mitigates depression by enhancing lncRNA Six3os1 expression and promoting histone H3K4 methylation at the BDNF promoter

Traditional Chinese medicine, particularly Zhi-zi-chi decoction (ZZCD), is gaining recognition as a potential treatment for depression. This study aimed to uncover the molecular mechanisms behind ZZCD's antidepressant effects, focusing on lncRNA Six3os1 and histone H3K4 methylation at the BDNF promoter. Network pharmacology and in vivo experiments were conducted to identify ZZCD targets and evaluate its impact on depression-related behaviours and neuron injury. The role of Six3os1 in recruiting KMT2A to the BDNF promoter and its effects on oxidative stress and neuron injury were investigated. ZZCD reduced depression-like behaviours and neuron injury in mice subjected to chronic stress. It upregulated Six3os1, which facilitated KMT2A recruitment to the BDNF promoter, leading to increased histone H3K4 methylation and enhanced BDNF expression. ZZCD also inhibited CORT-induced neuron injury, inflammatory response and oxidative stress in vitro. ZZCD's antidepressant properties involve Six3os1 upregulation, which exerts neuroprotective effects by inhibiting oxidative stress and neuron injury, thereby alleviating depressive symptoms. Targeting Six3os1 upregulation may offer a potential therapeutic intervention for depression.

Fabrication of a bioconjugated dual-functional SERS probe for facile compound screening and detection

Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive technique for both detection and structural characterizations. To further exploit these advantages, we designed and fabricated a dual-functional SERS probe for specific capture and fast detection of small molecule ligands binding to target protein from a mixture of compounds such as extracts of natural products. As a proof of concept, we synthesized SiO₂@Ag nanoclusters that are coated with 6-chlorohexanoic acid for covalent immobilization of serotonin transporter (5-HTT) fused with a Halo-tag through enzyme-substrate recognition. As such, we fabricated a bioconjugated SERS probe, and the synthesis, coating, protein immobilization, and affinity-based ligand binding have been characterized and verified by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and elemental mapping. By applying this probe to analyze Gardenia jasminoides extract, we have successfully identified crocin I as a compound binding to 5-HTT, which was further proved by using mass spectrometry (MS) and nuclear magnetic resonance (NMR). Taken together, we have developed a novel SERS probe by integrating the inherent strength of SERS in molecular analysis with an extended functionality of affinity-guided molecular capture, which has demonstrated the potential in drug screening of challenging systems.

Zhi-Zi-Chi Decoction Reverses Depressive Behaviors in CUMS Rats by Reducing Oxidative Stress Injury Via Regulating GSH/GSSG Pathway

Depression is one of the main diseases that lead to disability and loss of ability to work. As a traditional Chinese medicine, Zhi-zi-chi decoction is utilized to regulate and improve depression. However, the research on the antidepressant mechanism and efficacy material basis of Zhi-zi-chi decoction has not been reported yet. Our previous research has found that Zhi-Zi-chi decoction can reduce glutamate-induced oxidative stress damage to PC 12 cells, which can exert a neuroprotective effect, and the antidepressant effect of Zhi-Zi-chi decoction was verified in CUMS rat models. In this study, the animal model of depression was established by chronic unpredictable mild stimulation combined with feeding alone. The brain metabolic profile of depressed rats was analyzed by the method of metabolomics based on ultra-performance liquid chromatography-quadrupole/time-of-flight mass. 26 differential metabolites and six metabolic pathways related to the antidepressant of Zhi-zi-chi decoction were screened and analyzed. The targeted metabolism of the glutathione metabolic pathway was analyzed. At the same time, the levels of reactive oxygen species, superoxide dismutase, glutathione reductase, glutathione peroxidase in the brain of depressed rats were measured. Combined with our previous study, the antioxidant effect of the glutathione pathway in the antidepressant effect of Zhi-zi-chi decoction was verified from the cellular and animal levels respectively. These results indicated that Zhi-zi-chi decoction exerted a potential antidepressive effect associated with reversing the imbalance of glutathione and oxidative stress in the brain of depressed rats.