Quercitrin Rapidly Alleviated Depression-like Behaviors in Lipopolysaccharide-Treated Mice: The Involvement of PI3K/AKT/NF-κB Signaling Suppression and CREB/BDNF Signaling Restoration in the Hippocampus

Quercetin and Kaempferol inhibit HMC-1 activation via SOCE/NFATc2 signaling and suppress hippocampal mast cell activation in lipopolysaccharide-induced depressive mice

OBJECTIVE AND DESIGN

Mast cells (MCs), as the fastest immune responders, play a critical role in the progression of neuroinflammation-related diseases, especially in depression. Quercetin (Que) and kaempferol (Kae), as two major diet-derived flavonoids, inhibit MC activation and exhibit significant antidepressant effect due to their anti-inflammatory capacity. The study aimed to explore the mechanisms of inhibitory effect of Que and Kae on MC activation, and whether Que and Kae suppress hippocampal mast cell activation in LPS-induced depressive mice.

SUBJECTS AND TREATMENT

In vitro assays, human mast cells (HMC-1) were pretreated with Que or Kae for 1 h, then stimulated by phorbol 12-myristate 13-acetate (PMA) and 2,5-di-t-butyl-1,4-benzohydroquinone (tBHQ) for 3 h or 12 h. In vivo assays, Que or Kae was administered by oral gavage once daily for 14 days and then lipopolysaccharide (LPS) intraperitoneally injection to induce depressive behaviors.

METHODS

The secretion and expression of TNF-α were determined by ELISA and Western blotting. The nuclear factor of activated T cells (NFAT) transcriptional activity was measured in HMC-1 stably expressing NFAT luciferase reporter gene. Nuclear translocation of NFATc2 was detected by nuclear protein extraction and also was fluorescently detected in HMC-1 stably expressing eGFP-NFATc2. We used Ca2+ imaging to evaluate changes of store-operated calcium entry (SOCE) in HMC-1 stably expressing fluorescent Ca2+ indicator jGCamP7s. Molecular docking was used to assess interaction between the Que or Kae and calcium release-activated calcium modulator (ORAI). The  hippocampal mast cell accumulation and activation  were detected by toluidine blue staining and immunohistochemistry with β-tryptase.

RESULTS

In vitro assays of HMC-1 activated by PtBHQ (PMA and tBHQ), Que and Kae significantly decreased expression and secretion of TNF-α. Moreover, NFAT transcriptional activity and nuclear translocation of NFATc2 were remarkably inhibited by Que and Kae. In addition, the Ca2+ influx mediated by SOCE was suppressed by Que, Kae and the YM58483 (ORAI inhibitor), respectively. Importantly, the combination of YM58483 with Que or Kae had no additive effect on the inhibition of SOCE. The molecular docking also showed that Que and Kae both exhibit high binding affinities with ORAI at the same binding site as YM58483. In vivo assays, Que and Kae significantly reversed LPS-induced depression-like behaviors in mice, and inhibited hippocampal mast cell activation  in LPS-induced depressive mice.

CONCLUSIONS

Our results indicated that suppression of SOCE/NFATc2 pathway-mediated by ORAI channels may be the mechanism of inhibitory effect of Que and Kae on MC activation, and also suggested Que and Kae may exert the antidepressant effect through suppressing hippocampal mast cell activation.

Quercitrin improves cardiac remodeling following myocardial infarction by regulating macrophage polarization and metabolic reprogramming

The death and disability caused by myocardial infarction is a health problem that needs to be addressed worldwide, and poor cardiac repair and fibrosis after myocardial infarction seriously affect patient recovery. Postmyocardial infarction repair by M2 macrophages is of great significance for ventricular remodeling. Quercitrin (Que) is a common flavonoid in fruits and vegetables that has antioxidant, anti-inflammatory, antitumor and other effects, but whether it has a role in the treatment of myocardial infarction is unclear. In this study, we constructed a mouse myocardial infarction model and administered Que. We found through cardiac ultrasound that Que administration improved cardiac ejection fraction and reduced ventricular remodeling. Staining of heart sections and detection of fibrosis marker protein levels revealed that Que administration slowed fibrosis after myocardial infarction. Flow cytometry showed that the proportion of M2 macrophages in the mouse heart was increased and that the expression levels of M2 macrophage markers were increased in the Que-treated group. Finally, we identified by metabolomics that Que reduces glycolysis, increases aerobic phosphorylation, and alters arginine metabolic pathways, polarizing macrophages toward the M2 phenotype. Our research lays the foundation for the future application of Que in myocardial infarction and other cardiovascular diseases.

Quercetin alleviates chronic unpredictable mild stress-induced depression-like behavior by inhibiting NMDAR1 with α2δ-1 in rats

BACKGROUND

Depression is a serious mental disorder and the most prevalent cause of disability and suicide worldwide. Chronic unpredictable mild stress (CUMS) can lead to a significant acceleration of depression development. Quercetin (Que) is a flavonoid compound with a wide range of pharmacological effects. Recent studies have shown that quercetin can improve CUMS-induced depression-like behavior, but the mechanism of its improvement is still unclear. α2δ-1 is a regulatory subunit of voltage-gated calcium channel, which can interact with N-methyl-D-aspartate receptor (NMDAR) to form a complex.

OBJECTIVE

In this study, we found that Que could inhibit the increase of α2δ-1 and NMDAR expression in rat hypothalamus induced by CUMS. In pain, chronic hypertension and other studies have shown that α2δ-1 interacts with the NMDAR to form a complex, which subsequently affects the expression level of NMDAR. Consequently, the present study aimed to investigate the antidepressant effect of Que in vivo and in vitro and to explore its mechanism of action in terms of the interaction between α2δ-1 and NMDAR.

METHODS

Rats were randomly exposed to two stressors every day for 4 weeks to establish a CUMS rat model, then sucrose preference test (SPT), forced swimming test (FST), tail suspension test (TST), and open field test (OFT) were performed to detect the behavior of CUMS rats, so as to evaluate whether the CUMS rat model was successfully established and the improvement effect of Que on CUMS-induced depression-like behavior in rats. Experimental techniques such as serum enzyme-linked immunosorbent assay (ELISA), immunofluorescence, Western blot, and co-immunoprecipitation, as well as in vitro experiments, were used to investigate the mechanisms by which Que exerts its antidepressant effects.

RESULTS

Behavioral and ELISA test results showed that Que could produce a reduction in the excitability of the hypothalamic-pituitary-adrenal (HPA) axis in CUMS rats and lead to significant improvements in their depressive behavior. Western blot, immunofluorescence, and co-immunoprecipitation experiments showed that Que produced a decrease in NMDAR1 and α2δ-1 expression levels and interfered with α2δ-1 and NMDAR1 binding. In addition, the neural regulation mechanism of Que on antidepressant effect in PC12 cells knocked out α2δ-1 gene was further verified. Cellular experiments demonstrated that Que led to a reversal of up-regulation of NMDAR1 and α2δ-1 expression levels in corticosterone-injured PC12 cells, while Que had no effects on NMDAR1 expression in PC12 cells with the α2δ-1 gene knockout.

CONCLUSIONS

Que has a good antidepressant effect and can significantly improve the depression-like behavior caused by CUMS. It exerts antidepressant effects by inhibiting the expression level of α2δ-1, interfering with the interaction between α2δ-1 and NMDAR, and then reducing the excitability of the HPA axis.

LPS priming-induced immune tolerance mitigates LPS-stimulated microglial activation and social avoidance behaviors in mice

In this study, we investigated the regulatory mechanisms underlying the effects of LPS tolerance on the inflammatory homeostasis of immune cells. LPS priming-induced immune tolerance downregulated cyclooxygenase-2, and lowered the production of prostaglandin-E2 in microglial cells. In addition, LPS tolerance downregulated the expression of suppressor of cytokine signaling 3, and inducible nitric oxide synthase/nitric oxide; suppressed the LPS-mediated induction of tumor necrosis factor-α, interleukin (IL)-6, and IL-1; and reduced reactive oxygen species production in microglial cells. LPS stimulation increased the levels of the adaptive response-related proteins heme oxygenase-1 and superoxide dismutase 2, and the levels of heme oxygenase-1 (HO-1) enhanced after LPS priming. Systemic administration of low-dose LPS (0.5 mg/kg) to mice for 4 consecutive days attenuated high-dose LPS (5 mg/kg)-induced inflammatory response, microglial activation, and proinflammatory cytokine expression. Moreover, repeated exposure to low-dose LPS suppressed the recruitment of peripheral monocytes or macrophages to brain regions and downregulated the expression of proinflammatory cytokines. Notably, LPS-induced social avoidance behaviors in mice were mitigated by immune tolerance. In conclusion, immune tolerance may reduce proinflammatory cytokine expression and reactive oxygen species production. Our findings provide insights into the effects of endotoxin tolerance on innate immune cells and social behaviors.

Natural product Kaji-ichigoside F1 exhibits rapid antidepression via activating the AMPA-BDNF-mTOR pathway and inhibiting the NMDAR-CaMKIIα pathway

BACKGROUND

Depression is a common and recurrent neuropsychiatric disorder. Recent studies have shown that the N-methyl-d-aspartate (NMDA) receptor (NMDAR) is involved in the pathophysiology of depression. Previous studies have found that Kaji-ichigoside F1 (KF1) has a protective effect against NMDA-induced neurotoxicity. However, the antidepressant mechanism of KF1 has not been confirmed yet.

PURPOSE

In the present study, we aimed to evaluate the rapid antidepressant activity of KF1 and explore the underlying mechanism.

STUDY DESIGN

First, we explored the effect of KF1 on NMDA-induced hippocampal neurons and the underlying mechanism. Second, depression was induced in C57BL/6 mice via chronic unpredictable mild stress (CUMS), and the immediate and persistent depression-like behavior was evaluated using the forced swimming test (FST) after a single administration of KF1. Third, the contributions of NMDA signaling to the antidepressant effect of KF1 were investigated using pharmacological interventions. Fourth, CUMS mice were treated with KF1 for 21 days, and then their depression-like behaviors and the underlying mechanism were further explored.

METHODS

The FST was used to evaluate immediate and persistent depression-like behavior after a single administration of KF1 with or without NMDA pretreatment. The effect of KF1 on depressive-like behavior was investigated in CUMS mice by treating them with KF1 once daily for 21 days through the sucrose preference test, FST, open field test, and tail suspension test. Then, the effects of KF1 on the morphology and molecular and functional phenotypes of primary neuronal cells and hippocampus of mice were investigated by hematoxylin-eosin staining, Nissl staining, propidium iodide staining, TUNEL staining, Ca2+ imaging, JC-1 staining, ELISA, immunofluorescence analysis, RT-PCR, and Western blot.

RESULTS

KF1 could effectively improve cellular viability, reduce apoptosis, inhibit the release of LDH and Ca2+, and increase the mitochondrial membrane potential and the number of dendritic spines numbers in hippocampal neurons. Moreover, behavioral tests showed that KF1 exerted acute and sustained antidepressant-like effects by reducing Glu-levels and ameliorating neuronal damage in the hippocampus. Additionally, in vivo and in vitro experiments revealed that PSD95, Syn1, α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and brain-derived neurotrophic factor (BDNF) were upregulated at the protein level, and BDNF and AMPA were upregulated at the mRNA level. NR1 and NR2A showed the opposite trend.

CONCLUSION

These results confirm that KF1 exerts rapid antidepressant effects mainly by activating the AMPA-BDNF-mTOR pathway and inhibiting the NMDAR-CaMKIIα pathway. This study serves as a new reference for discovering rapid antidepressants.

Targeting autophagy to counteract neuroinflammation: A novel antidepressant strategy

Depression is a common disease that affects physical and mental health and imposes a considerable burden on afflicted individuals and their families worldwide. Depression is associated with a high rate of disability and suicide. It causes a severe decline in productivity and quality of life. Unfortunately, the pathophysiological mechanisms underlying depression have not been fully elucidated, and the risk of its treatment is still presented. Studies have shown that the expression of autophagic markers in the brain and peripheral inflammatory mediators are dysregulated in depression. Autophagy-related genes regulate the level of autophagy and change the inflammatory response in depression. Depression is related to several aspects of immunity. The regulation of the immune system and inflammation by autophagy may lead to the development or deterioration of mental disorders. This review highlights the role of autophagy and neuroinflammation in the pathophysiology of depression, sumaries the autophagy-targeting small moleculars, and discusses a novel therapeutic strategy based on anti-inflammatory mechanisms that target autophagy to treat the disease.

Agomelatine improves memory and learning impairments in a rat model of LPS-induced neurotoxicity by modulating the ERK/SorLA/BDNF/TrkB pathway

The mutual interplay between neuroinflammation, synaptic plasticity, and autophagy has piqued researchers' interest, particularly when it comes to linking their impact and relationship to cognitive deficits. Being able to reduce inflammation and apoptosis, melatonin has shown to have positive neuroprotective effects; that is why we thought to check the possible role of agomelatine (AGO) as a promising candidate that could have a positive impact on cognitive deficits. In the current study, AGO (40 mg/kg/day, p.o., 7 days) successfully ameliorated the cognitive and learning disabilities caused by lipopolysaccharide (LPS) in rats (250 μg/kg/day, i.p., 7 days). This positive impact was supported by improved histopathological findings and improved spatial memory as assessed using Morris water maze. AGO showed a strong ability to control BACE1 activity and to rein in the hippocampal amyloid beta (Aβ) deposition. Also, it improved neuronal survival, neuroplasticity, and neurogenesis by boosting BDNF levels and promoting its advantageous effects and by reinforcing the pTrkB expression. In addition, it upregulated the pre- and postsynaptic neuroplasticity biomarkers resembled in synapsin I, synaptophysin, and PSD-95. Furthermore, AGO showed a modulatory action on Sortilin-related receptor with A-type repeats (SorLA) pathway and adjusted autophagy. It is noteworthy that all of these actions were abolished by administering PD98059 a MEK/ERK pathway inhibitor (0.3 mg/kg/day, i.p., 7 days). In conclusion, AGO administration significantly improves memory and learning disabilities associated with LPS administration by modulating the ERK/SorLA/BDNF/TrkB signaling pathway parallel to its capacity to adjust the autophagic process.

Emerging evidence for endogenous neurosteroid modulation of pro-inflammatory and anti-inflammatory pathways that impact neuropsychiatric disease

This mini-review presents emerging evidence that endogenous neurosteroids modulate both pro- and anti-inflammatory signaling by immune cells and brain cells that contribute to depression, alcohol use disorders, and other inflammatory conditions. We first review the literature on pregnenolone and allopregnanolone inhibition of proinflammatory neuroimmune pathways in the periphery and the brain - effects that are independent of GABAergic mechanisms. We follow with evidence for neurosteroid enhancement of anti-inflammatory and protective pathways in brain and immune cells. These studies draw clinical relevance from a large body of evidence that pro-inflammatory immune signaling is dysregulated in many brain disorders and the fact that neurosteroids inhibit the same inflammatory pathways that are activated in depression, alcohol use disorders and other inflammatory conditions. Thus, we describe evidence that neurosteroid levels are decreased and neurosteroid supplementation has therapeutic efficacy in these neuropsychiatric conditions. We conclude with a perspective that endogenous regulation of immune balance between pro- and anti-inflammatory pathways by neurosteroid signaling is essential to prevent the onset of disease. Deficits in neurosteroids may unleash excessive pro-inflammatory activation which progresses in a feed-forward manner to disrupt brain networks that regulate stress, emotion and motivation. Neurosteroids can block various inflammatory pathways in mouse and human macrophages, rat brain and human blood and therefore provide new hope for treatment of intractable conditions that involve excessive inflammatory signaling.

Unlocking the Potential: Quercetin and Its Natural Derivatives as Promising Therapeutics for Sepsis

Sepsis is a syndrome of organ dysfunction caused by an uncontrolled inflammatory response, which can seriously endanger life. Currently, there is still a shortage of specific therapeutic drugs. Quercetin and its natural derivatives have received a lot of attention recently for their potential in treating sepsis. Here, we provide a comprehensive summary of the recent research progress on quercetin and its derivatives, with a focus on their specific mechanisms of antioxidation and anti-inflammation. To obtain the necessary information, we conducted a search in the PubMed, Web of Science, EBSCO, and Cochrane library databases using the keywords sepsis, anti-inflammatory, antioxidant, anti-infection, quercetin, and its natural derivatives to identify relevant research from 6315 articles published in the last five years. At present, quercetin and its 11 derivatives have been intensively studied. They primarily exert their antioxidation and anti-inflammation effects through the PI3K/AKT/NF-κB, Nrf2/ARE, and MAPK pathways. The feasibility of these compounds in experimental models and clinical application were also discussed. In conclusion, quercetin and its natural derivatives have good application potential in the treatment of sepsis.

Quercetin Ameliorates Cognitive Impairment in Depression by Targeting HSP90 to Inhibit NLRP3 Inflammasome Activation

Cognitive dysfunction was a common symptom of major depressive disorder (MDD). In previous studies, psychological stress leads to activation and proliferation of microglial cells in different brain regions. Quercetin, a bioflavonoid derived from vegetables and fruits, exerts anti-inflammatory effects in various diseases. To demonstrate the role of quercetin in the hippocampal inflammatory response in depress mice. The chronic unpredictable stress (CUS) depressive mice model built is used to explore the protective effects of quercetin on depression. Neurobehavioral test, protein expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and heat shock protein 90 (HSP90), and cytokines (IL-6, IL-1β, MCP-1, and TNF-α) were assessed. Quercetin ameliorated depressive-like behavior and cognitive impairment, and quercetin attenuates neuroinflammation and by targeting HSP90 to inhibit NLRP3 inflammasome activation. Quercetin inhibited the increase of HSP90 levels in the hippocampus and reverses inflammation-induced cognitive impairment. Besides, quercetin inhibited the increased level of cytokines (IL-6, IL-1β, MCP-1, and TNF-α) in the hippocampus of the depressive model mouse and the increased level of cytokines (IL-6, IL-1β, and MCP-1) in microglia. The current study indicated that quercetin mitigated depressive-like behavior and by targeting HSP90 to inhibit NLRP3 inflammasome activation in microglia and depressive mice model, meanwhile ameliorated cognitive impairment in depression. Quercetin has huge potential for the novel pharmacological efficacy of antidepressant therapy.

Sex differences in a corticosterone-induced depression model in mice: Behavioral, neurochemical, and molecular insights

Depression is characterized by a significant sex disparity, with higher rates observed in women compared to men. This study aimed to investigate the impact of sex on depressive behaviors and explore the underlying mechanisms using a corticosterone (CORT)-induced depression model in mice. Behavioral tests, Nissl staining, UPLC-MS/MS, and Western blot analysis were performed to assess behavioral changes, as well as neuronal alterations, neurotransmitter levels, and protein expressions in the hippocampus. The mice in the model group exhibited sex-specific anxiety- and depression-like behaviors. Nissl staining revealed structural abnormalities in the CA3 region of the hippocampus in females. Neurotransmitter analysis indicated decreased serotonin and norepinephrine levels in both sexes, while glutamate levels were elevated in females. Furthermore, female mice demonstrated elevated serum CORT levels. Western blot analysis revealed sex-specific alterations in specific protein expression. Female mice exhibited downregulated glucocorticoid receptor and brain-derived neurotrophic factor expression, whereas male mice showed minimal changes. Additionally, female mice displayed reduced phosphorylated AKT, phosphorylated PI3K, and phosphorylated mTOR levels. These findings enhance our understanding of sex-specific differences in the CORT-induced depression model and provide insights into the underlying mechanisms of depression. This research emphasizes sex in depression studies and supports tailored interventions.

Investigating the mechanism of Sinisan formula in depression treatment: a comprehensive analysis using GEO datasets, network pharmacology, and molecular docking

The herbal formula Sinisan (SNS) is a commonly used treatment for depression; however, its mechanism of action remains unclear. This article uses a combination of the GEO database, network pharmacology and molecular docking technologies to investigate the mechanism of action of SNS. The aim is to provide new insights and methods for future depression treatments. The study aims to extract effective compounds and targets for the treatment of depression from the T CMSP database. Relevant targets were searched using the GEO, Disgenet, Drugbank, PharmGKB and T T D databases, followed by screening of core targets. In addition, GO and KEGG pathway enrichment analyses were performed to explore potential pathways for the treatment of depression. Molecular docking was used to evaluate the potential targets and compounds and to identify the optimal core protein-compound complex. Molecular dynamics was used to further investigate the dynamic variability and stability of the complex. The study identified 118 active SNS components and 208 corresponding targets. Topological analysis of P P I networks identified 11 core targets. GO and KEGG pathway enrichment analyses revealed that the mechanism of action for depression involves genes associated with inflammation, apoptosis, oxidative stress, and the MAP K3 and P I3K-Akt signalling pathways. Molecular docking and dynamics simulations showed a strong binding affinity between these compounds and the screened targets, indicating promising biological activity. The present study investigated the active components, targets and pathways of SNS in the treatment of depression. Through a preliminary investigation, key signalling pathways and compounds were identified. These findings provide new directions and ideas for future research on the therapeutic mechanism of SNS and its clinical application in the treatment of depression.Communicated by Ramaswamy H. Sarma.

Geroscience-Centric Perspective for Geriatric Psychiatry: Integrating Aging Biology With Geriatric Mental Health Research

The geroscience hypothesis asserts that physiological aging is caused by a small number of biological pathways. Despite the explosion of geroscience research over the past couple of decades, the research on how serious mental illnesses (SMI) affects the biological aging processes is still in its infancy. In this review, we aim to provide a critical appraisal of the emerging literature focusing on how we measure biological aging systematically, and in the brain and how SMIs affect biological aging measures in older adults. We will also review recent developments in the field of cellular senescence and potential targets for interventions for SMIs in older adults, based on the geroscience hypothesis.

Neurosteroid [3α,5α]-3-hydroxy-pregnan-20-one enhances IL-10 production via endosomal TRIF-dependent TLR4 signaling pathway

Background

Previous studies demonstrated the inhibitory effect of allopregnanolone (3α,5α-THP) on the activation of inflammatory toll-like receptor 4 (TLR4) signals in RAW264.7 macrophages and the brains of selectively bred alcohol-preferring (P) rats. In the current study, we investigated the impact of 3α,5α-THP on the levels of IL-10 and activation of the TRIF-dependent endosomal TLR4 pathway.

Methods

The amygdala and nucleus accumbens (NAc) of P rats, which exhibit innately activated TLR4 pathways as well as RAW264.7 cells, were used. Enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays were used to ascertain the effects of 3α,5α-THP on the TRIF-dependent endosomal TLR4 pathway and endosomes were isolated to examine translocation of TLR4 and TRIF. Additionally, we investigated the effects of 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) on the levels of IL-10 in RAW264.7 macrophages. Finally, we examined whether inhibiting TRIF (using TRIF siRNA) in RAW264.7 cells altered the levels of IL-10.

Results

3α,5α-THP administration facilitated activation of the endosomal TRIF-dependent TLR4 pathway in males, but not female P rats. 3α,5α-THP increased IL-10 levels (+13.2 ± 6.5%) and BDNF levels (+21.1 ± 11.5%) in the male amygdala. These effects were associated with increases in pTRAM (+86.4 ± 28.4%), SP1 (+122.2 ± 74.9%), and PI(3)K-p110δ (+61.6 ± 21.6%), and a reduction of TIRAP (-13.7 ± 6.0%), indicating the activation of the endosomal TRIF-dependent TLR4 signaling pathway. Comparable effects were observed in NAc of these animals. Furthermore, 3α,5α-THP enhanced the accumulation of TLR4 (+43.9 ± 11.3%) and TRIF (+64.8 ± 32.8%) in endosomes, with no significant effect on TLR3 accumulation. Additionally, 3α,5α-THP facilitated the transition from early endosomes to late endosomes (increasing Rab7 levels: +35.8 ± 18.4%). In RAW264.7 cells, imiquimod (30 µg/mL) reduced IL-10 while 3α,5α-THP and 3α,5α-THDOC (0.1, 0.3, and 1.0 µM) restored IL-10 levels. To determine the role of the TRIF-dependent TLR4 signaling pathway in IL-10 production, the downregulation of TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%). TRIF (-62.9 ± 28.2%) in RAW264.7 cells led to a reduction in IL-10 levels (-42.3 ± 8.4%) and 3α,5α-THP (1.0 µM) no longer restored the reduced IL-10 levels.

Conclusion

The results demonstrate 3α,5α-THP enhancement of the endosomal TLR4-TRIF anti-inflammatory signals and elevations of IL-10 in male P rat brain that were not detected in female P rat brain. These effects hold significant implications for controlling inflammatory responses in both the brain and peripheral immune cells.

Effects of Artemisia annua L. on postmenopausal syndrome in ovariectomized mice

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. (Asteraceae) has been used as an antipyretic and anti-parasitic drug in traditional medicine for more than 2000 years. It has also been prescribed to treat symptoms caused by deficiency of Yin, which might be observed in menopausal state from the point of view of traditional medicine.

AIM OF THE STUDY

We hypothesized that A. annua might be useful for treating menopausal disorders with less adverse effects than hormone replacement therapy. Thus, the aim of the present study was to investigate effects of A. annua on postmenopausal symptoms of ovariectomized (OVX) mice.

MATERIALS AND METHODS

OVX mice were employed as a model for postmenopausal disorders. Mice were treated with a water extract of A. annua (EAA; 30, 100 or 300 mg/kg, p.o.) or 17β-estradiol (E2; 0.5 mg/kg, s.c.) for 8 weeks. Open field test (OFT), novel object recognition task (NOR), Y-maze test, elevated plus maze test (EPM), splash test and tail suspension test (TST) were conducted to determine whether EAA could ameliorate postmenopausal symptoms. Phosphorylated levels of extracellular signal-regulated kinase (ERK), protein kinase B (Akt), and glycogen synthase kinase-3β (GSK-3β), β-catenin and expression level of synaptophysin in the cortex and hippocampus were evaluated by Western blot analysis.

RESULTS

EAA treatment significantly increased the discrimination index in NOR, decreased the time in closed arm than in open arm in EPM, increased grooming time in splash test, and decreased immobility time in TST, as did E2 treatment. In addition, decreased phosphorylation levels of ERK, Akt, GSK-3β, and β-catenin and expression levels of synaptophysin in the cortex and hippocampus after OVX were reversed by administration of EAA and E2.

CONCLUSION

These results suggest that A. annua can ameliorate postmenopausal symptoms such as cognitive dysfunction, anxiety, anhedonia, and depression by activating ERK, Akt, and GSK-3β/β-catenin signaling pathway and hippocampal synaptic plasticity, and that A. annua would be a novel treatment for postmenopausal symptoms.

The pharmacological mechanism of chaihu-jia-longgu-muli-tang for treating depression: integrated meta-analysis and network pharmacology analysis

Aim: Chaihu-jia-Longgu-Muli-tang (CLM) is derived from "Shang Han Lun" and is traditionally prescribed for treating depression. However, there is still a lack of evidence for its antidepressant effects, and the underlying mechanism is also unclear. This study aimed to assess clinical evidence on the efficacy of CLM in patients with depression using a meta-analysis and to explore its underlying antidepressant molecular mechanisms via network pharmacology. Methods: Eight open databases were searched for randomized controlled trials (RCTs) comparing the effects of CLM alone or combined with serotonin-norepinephrine reuptake inhibitors (SNRIs) and selective serotonin reuptake inhibitors (SSRIs) in patients with depression, evaluating the total effective rate of the treatment group (CLM alone or combined with SSRIs/SNRIs) and the control group (SNRIs or SSRIs), and comparing changes in depression scale, anxiety scale, sleep scale, inflammation indicators and adverse effects. Subsequently, the active ingredients and target genes of CLM were screened through six databases. Then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein-protein interaction (PPI) network and topology analysis were performed. Finally, Molecular docking was applied to evaluate the binding affinity between components and predicted targets. Results: Twenty-four RCTs with a total of 2,382 patients were included. For the efficacy of antidepression and adverse effects, whether CLM alone or in combination with SSRIs/SNRIs, the treatment group has no inferior to that of the control group. Additionally, the intervention of CLM + SSRI significantly improved the symptoms of anxiety and insomnia, and reduced serum IL-6 and TNF-α levels. For network pharmacology, a total of 129 compounds and 416 intersection targets in CLM were retrieved. The interaction pathway between CLM and depression is mainly enriched in PI3K-Akt, JAK-STAT, and NF-κB signaling pathway, PIK3R1, MAPK3, and AKT1 may be the potential targets of Stigmasterol, β-stiosterol, coumestrol. Conclusion: Compared to SSRIs/SNRIs alone, CLM is more effective and safe in treating depression. It not only significantly alleviates depressive mood, but improves symptoms such as anxiety and insomnia, with fewer side effects, especially in combination with SSRI. Its antidepressant mechanism may be correlated with the regulation of the PI3K/Akt signaling pathway and inhibiting inflammatory response.

A Window to the Brain: The Retina to Monitor the Progression and Efficacy of Saffron Repron® Pre-Treatment in an LPS Model of Neuroinflammation and Memory Impairment

A mechanism shared by most neurodegenerative diseases, like Alzheimer's disease (AD) and Parkinson's disease (PD), is neuroinflammation. It has been shown to have a link between cognitive impairment and retinal function under neuroinflammatory conditions, confirming the essential role of the retina as a window to the brain. Here, we characterize a mouse model of LPS-induced neuroinflammation describing the parallel deterioration of both memory and visual function. Then, we demonstrate, using the Novel Object Recognition test (NOR) and electroretinogram (ERG) recordings, that preventive, chronic treatment with saffron Repron® is able to reduce the neuroinflammation process and prevent the impairment of both cognitive and visual function. The improvement in behavioral and visual function is confirmed by the pattern of expression of neuroinflammation-related genes and related proteins where pre-treatment with Repron® saffron presents a positive modulation compared with that obtained in animals treated with LPS alone. These results hold for retinal tissue and partially in the brain, where it appears that the onset of damage was delayed. This trend underlines the critical role of the retina as a most sensitive portion of the central nervous system to LPS-induced damage and could be used as a "sensor" for the early detection of neurodegenerative diseases such as Alzheimer's.

Flavonoids from Seabuckthorn (Hippophae rhamnoides L.) restore CUMS-induced depressive disorder and regulate the gut microbiota in mice

Seabuckthorn (Hippophae rhamnoides L.), which is enriched with flavonoids, including isorhamnetin, quercetin and kaempferol, is a representative example of "medicine food homology" targeting several diseases. Major depressive disorders seriously threaten mental health worldwide and may even lead to death. Chronic unpredictable mild stress (CUMS)-induced depressive-like symptoms in mice are usually considered as the highest similarity to the situation in humans. Herein, we determined the potential functions of the flavonoid-enriched fraction from Seabuckthorn, which was named SBF, in treating major depressive disorder in mice. In the CUMS-induced mouse model, the intake of SBF reversed their depressive behaviors and relieved the CUMS-disturbed levels of neurotrophins, neurotransmitters, stress-related hormones, and inflammation-related cytokines. Additionally, the treatment of depressive mice with SBF showed ability to regulate the gut microbiota, especially in decreasing the abundance of Lactobacillaceae, while increasing the abundance of Lachnospiraceae at the family level. The results suggest the beneficial effects of Seabuckthorn flavonoids in functioning as a health food supplement to treat major depressive disorders.

Inulin-type oligosaccharides of Morinda officinalis exerted antidepressant effects by reducing hippocampal inflammation

Neuroinflammation contributes to the pathogenesis of depression. Inulin-type oligosaccharides of Morinda officinalis (IOMO) exert antidepressant-like effects in rodents and patients with depression, while the underlying mechanisms remain unclear. This study used chronic restraint stress (CRS) and lipopolysaccharide (LPS) to induce depression-like behaviors in mice. Western blotting and ELISA analysis were used to investigate the effects of IOMO on inflammatory cytokine levels. Immunofluorescence analysis was used to investigate the effects of IOMO on hippocampal NLRP3 inflammasome and microglial cells. The results suggested that 6 weeks of CRS induced significant depression-like behaviors based on the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST), which were accompanied by increases in the expression of IL-6 and the activation of hippocampal microglial cells. Chronic treatment with IOMO (25 mg/kg, i.g.) for 28 days significantly reversed these depression-like behaviors and inhibited the activation of microglial cells. Furthermore, LPS (0.5 mg/kg, i.p.) also significantly induced depression-like behaviors in the TST, FST, and novelty-suppressed feeding test (NSFT), as well as increased the expression of IL-1β and caspase-1, and activated the microglial cells and the NLRP3 inflammasome in the hippocampus. Treatment with IOMO for 9 days significantly reversed these depression-like behaviors and normalized the LPS-induced activation of the microglial cells and NLRP3 inflammasome. Taken together, these results suggested that IOMO exerted antidepressant-like effects via hippocampal microglial NLRP3 inflammasome mediation followed by caspase-1 inhibition and the production of IL-1β. These findings provide a basis for developing new antidepressants targeting the microglial NLRP3 inflammasome.

A new perspective on hippocampal synaptic plasticity and post-stroke depression

Post-stroke depression, a common complication after stroke, severely affects the recovery and quality of life of patients with stroke. Owing to its complex mechanisms, post-stroke depression treatment remains highly challenging. Hippocampal synaptic plasticity is one of the key factors leading to post-stroke depression; however, the precise molecular mechanisms remain unclear. Numerous studies have found that neurotrophic factors, protein kinases and neurotransmitters influence depressive behaviour by modulating hippocampal synaptic plasticity. This review further elaborates on the role of hippocampal synaptic plasticity in post-stroke depression by summarizing recent research and analysing possible molecular mechanisms. Evidence for the correlation between hippocampal mechanisms and post-stroke depression helps to better understand the pathological process of post-stroke depression and improve its treatment.

Flavonoids from Seabuckthorn (Hippophae rhamnoides L.) mimic neurotrophic functions in inducing neurite outgrowth in cultured neurons: Signaling via PI3K/Akt and ERK pathways

BACKGROUND

Various brain disorders, including neurodegenerative diseases and major depressive disorders, threaten an increasing number of patients. Seabuckthorn, a fruit from Hippophae rhamnoides L., is an example of "medicine food homology". The fruit has enriched flavonoids that reported to have benefits in treating cognitive disorders. However, the studies on potential functions of Seabuckthorn and/or its flavonoid-enriched fraction in treating neurodegenerative disorders are limited.

PURPOSE

This study aimed to determine the ability and mechanism of the flavonoid-enriched fraction of Seabuckthorn (named as SBF) in mimicking the neurotrophic functions in inducing neurite outgrowth of cultured neurons.

METHODS

Cultured PC12 cell line, SH-SY5Y cell line and primary neurons (cortical and hippocampal neurons isolated from E17-19 SD rat embryos) were the employed models to evaluate SBF in inducing neurite outgrowth by comparing to the effects of NGF and BDNF. Immuno-fluorescence staining was applied to identify the morphological change during the neuronal differentiation. Luciferase assay was utilized for analyzing the transcriptional regulation of neurofilaments and cAMP/CREB-mediated gene. Western blot assay was conducted to demonstrate the expressions of neurofilaments and phosphorylated proteins.

RESULTS

The application of SBF induced neuronal cell differentiation, and this differentiating activation was blocked by the inhibitors of PI3K/Akt and ERK pathways. Additionally, SBF showed synergy with neurotrophic factors in stimulating the neurite outgrowth of cultured neurons. Moreover, the major flavonoids within SBF, i.e., isorhamnetin, quercetin and kaempferol, could account for the neurotrophic activities of SBF.

CONCLUSION

Seabuckthorn flavonoids mimicked neurotrophic functions in inducing neuronal cell differentiation via activating PI3K/Akt and ERK pathways. The results suggest the beneficial functions of Seabuckthorn as a potential health food supplement in treating various brain disorders, e.g., neurodegenerative diseases.

TIPE2 regulates the response of BV2 cells to lipopolysaccharide by the crosstalk between PI3K/AKT signaling and microglia M1/M2 polarization

Tumor necrosis factor (TNF)-α-induced protein 8-like 2 (TIPE2) is a crucial negative regulator of both adaptive and innate immunity, which helps maintain the dynamic balance of the immune system by negatively regulating the signaling of T-cell receptors (TCR) and Toll-like receptors (TLR). In this study, we aimed to investigate the role and molecular mechanism of TIPE2 using a lipopolysaccharide (LPS)-induced inflammatory injury model in BV2 cells. Specifically, we constructed a BV2 cell line of TIPE2-overexpression or TIPE2-knockdown via lentiviral transfection. Our results demonstrated that overexpression of TIPE2 downregulated the expression of pro-inflammatory cytokines IL-1β and IL-6, which was reversed by knockdown of TIPE2 in the inflammation model of BV2 cells. In addition, overexpression of TIPE2 resulted in the conversion of BV2 cells to the M2 phenotype, while the knockdown of TIPE2 promoted the transformation of BV2 cells to the M1 phenotype. Notably, our co-culture experiments with neuronal cells SH-SY5Y showed that the overexpression of TIPE2 in inflammation-injured BV2 cells exhibited a protective effect on the neuronal cells. Finally, western blot analysis demonstrated that TIPE2 significantly reduced the expression of p-PI3K, p-AKT, p-p65, and p-IκBα in LPS treated BV2 cells, and inhibited the activation of NF-κB through the dephosphorylation of PI3K/AKT. These results suggest that TIPE2 plays an important role in mediating neuroinflammatory responses and may be involved in neuroprotection by modulating the phenotypic changes of BV2 cells and regulating the pro-inflammatory responses through the PI3K/AKT and NF-κB signaling pathways. In conclusion, our study provides new insights into the crucial role of TIPE2 in regulating neuroinflammatory responses and highlights its potential as a therapeutic target for neuroprotection.

Analysis of target organs of Houttuynia cordata: A study on the anti-inflammatory effect of upper respiratory system

ETHNOPHARMACOLOGICAL RELEVANCE

Houttuynia cordata Thunb. (HC) is a traditional anti-pyretic herb that is classified as the lung meridian in traditional Chinese medicine. However, no articles have explored the main organs responsible for the anti-inflammatory activities of HC.

AIM OF THE STUDY

The aim of the study was to investigate the meridian tropism theory of HC in lipopolysaccharide (LPS)-induced pyretic mice, as well as to identify the underlying mechanisms.

MATERIALS AND METHODS

Transgenic mice carrying the luciferase gene driven by nuclear factor-κB (NF-κB) were intraperitoneally injected with LPS and orally administered standardized concentrated HC aqueous extract. The phytochemicals present in the HC extract were analyzed using high-performance liquid chromatography. In vivo and ex vivo luminescent imaging from transgenic mice was used to investigate the meridian tropism theory and anti-inflammatory effects of HC. Microarray analysis of gene expression patterns was used to elucidate the therapeutic mechanisms of HC.

RESULTS

HC extract was found to contain phenolic acids, such as protocatechuic acid (4.52%) and chlorogenic acid (8.12%), as well as flavonoids like rutin (2.05%) and quercitrin (7.73%). The bioluminescent intensities induced by LPS in the heart, liver, respiratory system, and kidney were significantly suppressed by HC, while the maximal decrease (about 90% reduction) of induced luminescent intensity was observed in the upper respiratory tract. These data suggested that upper respiratory system might be the target for HC anti-inflammatory abilities. HC affected the processes involved in innate immunity, such as chemokine-mediated signaling pathway, inflammatory response, chemotaxis, neutrophil chemotaxis, and cellular response to interleukin-1 (IL-1). Moreover, HC significantly reduced the proportions of p65-stained cells and the amount of IL-1β in trachea tissues.

CONCLUSION

Bioluminescent imaging coupled with gene expression profile was used to demonstrate the organ selectivity, anti-inflammatory effects, and therapeutic mechanisms of HC. Our data demonstrated for the first time that HC displayed lung meridian-guiding effects and exhibited great anti-inflammatory potential in the upper respiratory tract. The NF-κB and IL-1β pathways were associated with the anti-inflammatory mechanism of HC against LPS-provoked airway inflammation. Moreover, chlorogenic acid and quercitrin might be involved in the anti-inflammatory properties of HC.

Polyphenols as novel interventions for depression: exploring the efficacy, mechanisms of action, and implications for future research

Numerous animal and human studies have assessed the relationship between polyphenols and outcomes related to depression. However, no comprehensive synthesis of the main findings has been conducted. The aim of this manuscript was to systematically review the available evidence from animal and human studies on the association and the effects of dietary polyphenols on depression and provide recommendations for future research. We based our review on 163 preclinical animal, 16 observational and 44 intervention articles assessing the relationship between polyphenols and outcomes related to depression. Most animal studies demonstrated that exposure to polyphenols alleviated behaviours reported to be associated with depression. However, human studies are less clear, with some studies reporting and inverse relationship between the intake of some polyphenols, and polyphenol rich foods and depression risk and symptoms, while others reporting no association or effect. Hence, while there has been extensive research conducted in animals and there is some supporting evidence in humans, further human studies are required, particularly in younger and clinical populations.

Research Progress on the Pharmacodynamic Mechanisms of Sini Powder against Depression from the Perspective of the Central Nervous System

Depression is a highly prevalent emotional disorder characterized by persistent low mood, diminished interest, and loss of pleasure. The pathological causes of depression are associated with neuronal atrophy, synaptic loss, and neurotransmitter activity decline in the central nervous system (CNS) resulting from injuries, such as inflammatory responses. In Traditional Chinese Medicine (TCM) theory, patients with depression often exhibit the liver qi stagnation syndrome type. Sini Powder (SNP) is a classic prescription for treating such depression-related syndrome types in China. This study systematically summarized clinical applications and experimental studies of SNP for treatments of depression. We scrutinized the active components of SNP with blood-brain barrier (BBB) permeability and speculated about the corresponding pharmacodynamic pathways relevant to depression treatment through intervening in the CNS. Therefore, this article can enhance our understanding of SNP's pharmacological mechanisms and formula construction for depression treatment. Moreover, a re-demonstration of this classic TCM prescription in the modern-science language is of great significance for future drug development and research.

Study on correlations of BDNF, PI3K, AKT and CREB levels with depressive emotion and impulsive behaviors in drug-naïve patients with first-episode schizophrenia

BACKGROUND

The pathogenesis of schizophrenia is still unknown. Nearly a half of schizophrenic patients have depressive symptoms and even some impulsive behaviors. The definite diagnosis of schizophrenia is an immense challenge. Molecular biology plays an essential role in the research on the pathogenesis of schizophrenia.

OBJECTIVE

This study aims to analyze the correlations of serum protein factor levels with depressive emotion and impulsive behaviors in drug-naïve patients with first-episode schizophrenia.

METHODS

Seventy drug-naïve patients with first-episode schizophrenia and sixty-nine healthy volunteers from the health check center in the same period participated in this study. In both the patient group and control group, brain-derived neurotrophic factor (BDNF), phosphatidylin-ositol-3-kinase (PI3K), protein kinase B (AKT), and cAMP-response element binding protein (CREB) levels in the peripheral blood were tested by enzyme-linked immunosorbent assay (ELISA). The depressive emotion and impulsive behaviors were evaluated with Chinese versions of the Calgary Depression Scale for Schizophrenia (CDSS) and Short UPPS-P Impulsive Behavior Scale (S-UPPS-P), respectively.

RESULTS

The serum levels of BDNF, PI3K, and CREB in the patient group were lower than those in the control group, while AKT level, total CDSS score and total S-UPPS-P score were all higher. In the patient group, total CDSS score, and total S-UPPS-P score were both correlated negatively with BDNF, PI3K, and CREB levels but positively with AKT level, and the lack-of-premeditation (PR) sub-scale score was not significantly correlated with BDNF, PI3K, AKT, and CREB levels.

CONCLUSION

Our study results showed that the peripheral blood levels of BDNF, PI3K, AKT, and CREB in drug-naïve patients with first-episode schizophrenia were significantly different from those in the control group. The levels of these serum protein factors are promising biomarkers to predict schizophrenic depression and impulsive behaviors.

Quantitative proteomics reveals the therapeutic effects of RFAP against depression via pathway regulation of long-term depression and potentiation

Ethnopharmacological relevance

RFAP is a compound extraction complex of four Traditional Chinese Medicine (TCM), including the dry bark of Paeonia lactiflora Pall. (Radix Paeoniae Alba), Gardenia jasminoides J. Ellis (Fructus Gardeniae), Albizia julibrissin Durazz. (Albizia julibrissin Durazz), and Paeonia × suffruticosa Andrews (Peony bark). Not only RFAP but also the individual ingredients have been commonly used for the treatment of depression in the clinic. However, the underlying mechanism of pharmacology is difficult to interpret since its holistic and multidrug nature.

Aim of the study

This study aimed to elucidate the potential antidepressant mechanism of RFAP in the treatment of chronic unpredictable mild stress (CUMS) rats' model via the quantitative proteomics approach.

Materials and methods

We established the CUMS rats' model and evaluated the efficacy of RFAP using multiple behavior assays, including the sugar preference test, open field test, and forced swimming test. Then label-free quantitative proteomics analyses were performed to evaluate the integrated changes of proteome profiling in control, CUMS, RFAP low dose, and RFAP high dose groups. Finally, we validated the critical changed proteins in the pathways of long-term depression and potentiation via RT-PCR and Western blotting assays.

Results

We successfully established the CUMS rats' model. The behavior assays indicated that the rats demonstrated a tendency to behavioral despair after four weeks. Label-free quantitative proteomics showed that 107 proteins were significantly upregulated and 163 proteins were downregulated in the CUMS group compared to the control group. These differentially expressed proteins were involved in long-term potentiation, long-term depression, nervous system development, neuronal synaptic structural constituent of ribosome, ATP metabolic process, learning or memory, and cellular lipid metabolic process. RFAP treatment partially restored the differentially expressed protein profile. The protective effect of RFAP on behavioral assessment were consistent with the results of proteomics.

Conclusions

The results indicated that RFAP exerted a synergistic effect on CUMS by regulating long-term inhibition and potentiation-related proteins.

Neuroprotective Potentials of Flavonoids: Experimental Studies and Mechanisms of Action

Neurological and neurodegenerative diseases, particularly those related to aging, are on the rise, but drug therapies are rarely curative. Functional disorders and the organic degeneration of nervous tissue often have complex causes, in which phenomena of oxidative stress, inflammation and cytotoxicity are intertwined. For these reasons, the search for natural substances that can slow down or counteract these pathologies has increased rapidly over the last two decades. In this paper, studies on the neuroprotective effects of flavonoids (especially the two most widely used, hesperidin and quercetin) on animal models of depression, neurotoxicity, Alzheimer's disease (AD) and Parkinson's disease are reviewed. The literature on these topics amounts to a few hundred publications on in vitro and in vivo models (notably in rodents) and provides us with a very detailed picture of the action mechanisms and targets of these substances. These include the decrease in enzymes that produce reactive oxygen and ferroptosis, the inhibition of mono-amine oxidases, the stimulation of the Nrf2/ARE system, the induction of brain-derived neurotrophic factor production and, in the case of AD, the prevention of amyloid-beta aggregation. The inhibition of neuroinflammatory processes has been documented as a decrease in cytokine formation (mainly TNF-alpha and IL-1beta) by microglia and astrocytes, by modulating a number of regulatory proteins such as Nf-kB and NLRP3/inflammasome. Although clinical trials on humans are still scarce, preclinical studies allow us to consider hesperidin, quercetin, and other flavonoids as very interesting and safe dietary molecules to be further investigated as complementary treatments in order to prevent neurodegenerative diseases or to moderate their deleterious effects.

3',4'-Dihydroxyflavonol Attenuates Lipopolysaccharide-Induced Neuroinflammatory Responses of Microglial Cells by Suppressing AKT-mTOR and NF-κB Pathways

Microglia-related neuroinflammation contributes to the pathogenesis of a variety of neurodegenerative disorders such as Alzheimer's disease. The synthetic flavonoid, 3',4'-dihydroxyflavonol (3,3',4'-trihydroxyflavone), has been shown to protect brain or myocardial ischemia reperfusion-induced cell death and prevent the aggregation of amyloid-β protein, a process that causes progressive neurodegeneration in Alzheimer's disease. Here, we explored the anti-neuroinflammatory ability of 3',4'-dihydroxyflavonol in lipopolysaccharide (LPS)-activated MG6 microglial cells. 3',4'-Dihydroxyflavonol attenuated LPS-induced tumor necrosis factor-α and nitric oxide secretion in MG6 cells. LPS-induced phosphorylation of mammalian target of rapamycin (mTOR), nuclear factor-κB (NF-κB), and protein kinase B (AKT) (which are all associated with the neuroinflammatory response in microglia) were attenuated by 3',4'-dihydroxyflavonol treatment. Treatment with the mTOR inhibitor, rapamycin, NF-κB inhibitor, caffeic acid phenethyl ester, or AKT inhibitor, LY294002, also attenuated LPS-induced tumor necrosis factor-α and nitric oxide secretion in MG6 cells. LY294002 treatment attenuated LPS-induced phosphorylation of mTOR and NF-κB in MG6 cells. Hence, our study suggests that 3',4'-dihydroxyflavonol can attenuate the neuroinflammatory response of microglial cells by suppressing the AKT-mTOR and NF-κB pathways.

Cuscutae semen alleviates CUS-induced depression-like behaviors in mice via the gut microbiota-neuroinflammation axis

Introduction: Major depressive disorder is a mental disease with complex pathogenesis and treatment mechanisms involving changes in both the gut microbiota and neuroinflammation. Cuscutae Semen (CS), also known as Chinese Dodder seed, is a medicinal herb that exerts several pharmacological effects. These include neuroprotection, anti-neuroinflammation, the repair of synaptic damage, and the alleviation of oxidative stress. However, whether CuscutaeSemen exerts an antidepressant effect remains unknown. Methods: In this study, we evaluated the effect of CS on chronic unpredictable stress (CUS)-induced depression-like behaviors in mice by observing changes in several inflammatory markers, including proinflammatory cytokines, inflammatory proteins, and gliocyte activation. Meanwhile, changes in the gut microbiota were analyzed based on 16 S rRNA sequencing results. Moreover, the effect of CS on the synaptic ultrastructure was detected by transmission electron microscopy. Results: We found that the CS extract was rich in chlorogenic acid and hypericin. And CS relieved depression-like behaviors in mice exposed to CUS. Increased levels of cytokines (IL-1β and TNF-α) and inflammatory proteins (NLRP3, NF-κB, and COX-2) induced by CUS were reversed after CS administration. The number of astrocytes and microglia increased after CUS exposure, whereas they decreased after CS treatment. Meanwhile, CS could change the structure of the gut microbiota and increase the relative abundance of Lactobacillus. Moreover, there was a significant relationship between several Lactobacilli and indicators of depression-like behaviors and inflammation. There was a decrease in postsynaptic density after exposure to CUS, and this change was alleviated after CS treatme. Conclusion: This study found that CS treatment ameliorated CUS-induced depression-like behaviors and synaptic structural defects in mice via the gut microbiota-neuroinflammation axis. And chlorogenic acid and hypericin may be the main active substances for CS to exert antidepressant effects.

Leaves of Cedrela sinensis Attenuate Chronic Unpredictable Mild Stress-Induced Depression-like Behavior via Regulation of Hormonal and Inflammatory Imbalance

This study aimed to evaluate the protective effects of ethyl acetate fraction from Cedrela sinensis (EFCS) against chronic unpredictable mild stress (CUMS)-induced behavioral dysfunction and stress response in C57BL/6 mice. The physiological compounds of EFCS were identified as rutin, isoquercitrin, ethyl gallate, quercitrin, kaempferol-3-O-rhamnoside, and ethyl digallate, using UPLC-Q-TOF/MS^E. To evaluate the neuroprotective effect of EFCS, H₂O₂^- and corticosterone-induced neuronal cell viability was conducted in human neuroblastoma MC-IXC cells. It was found that EFCS alleviated depression-like behavior by conducting the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and tail suspension test (TST). EFCS inhibited mitochondrial dysfunction related to neuronal energy metabolism by regulating reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and ATP contents in brain tissue. In addition, the administration of EFCS regulated the stress hormones in serum. EFCS regulated stress-related indicators such as CRF, ACTH, CYP11B1, and BDNF. Moreover, EFCS downregulated the inflammatory responses and apoptosis proteins such as caspase-1, TNF-α, IL-1β, p-JNK, BAX, and p-tau in brain tissues. These results suggest that EFCS might be a potential natural plant material that alleviates CUMS-induced behavior disorder by regulating inflammation in brain tissue against CUMS-induced depression.

Antidepressant effects of cherry leaf decoction on a chronic unpredictable mild stress rat model based on the Glu/GABA-Gln metabolic loop

Cherry leaves (Prunus pseudocerasus Lindl. [Rosaceae]), a traditional Chinese herbal medicine, can regulate the factors closely related to depression including inflammatory cytokines, oxidative stress and blood glucose level. However, the antidepressant effects of cherry leaves and underlying neuromodulatory mechanisms remain relatively have not been elucidated explicitly. The present study investigated the antidepressant effects of cherry leaf decoction (CLD). The underlying neuromodulatory mechanism was explored by examining the glutamate (Glu)/γ-aminobutyric acid (GABA)-glutamine (Gln) metabolic loop. The chronic unpredictable mild stress (CUMS) rodent model was used in this study. The main flavonoids components of CLD were identified using high-performance liquid chromatography (HPLC). The antidepressant effects of CLD were assessed throughout behavioural tests including the bodyweight, sucrose preference test (SPT), forced swimming test (FPT) and tail suspension test (TST). Moreover, The baseline levels of serum adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were quantified. The expression of proteins integrally involved in the Glu/GABA-Gln metabolic loop were observed and quantified by Western blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. This study found that CLD ameliorated depressive-like behaviours induced by CUMS. The increase of serum ACTH and CORT baseline levels induced by CUMS was also reversed after CLD intervention. Furthermore, CUMS reduced the expression of GAD65, GAD67, GLT-1, GS and GABA_A and increased NMDAR1 levels in the rat hippocampus, which was normalized by CLD treatment. The findings demonstrated that CLD could ameliorate the depression-like behaviours induced by CUMS, potentially through the inhibition of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and the regulation of Glu/GABA-Gln metabolic loop.

Beneficial effects of natural flavonoids on neuroinflammation

Neuroinflammation is the fundamental immune response against multiple factors in the central nervous system and is characterized by the production of inflammatory mediators, activated microglia and astrocytes, and the recruitment of innate and adaptive immune cells to inflammatory sites, that contributes to the pathological process of related brain diseases, such as Alzheimer’s disease, Parkinson’s disease, depression, and stroke. Flavonoids, as a species of important natural compounds, have been widely revealed to alleviate neuroinflammation by inhibiting the production of pro-inflammatory mediators, elevating the secretion of anti-inflammatory factors, and modulating the polarization of microglia and astrocyte, mainly via suppressing the activation of NLRP3 inflammasome, as well as NF-κB, MAPK, and JAK/STAT pathways, promoting Nrf2, AMPK, BDNF/CREB, Wnt/β-Catenin, PI3k/Akt signals and SIRT1-mediated HMGB1 deacetylation. This review will provide the latest and comprehensive knowledge on the therapeutic benefits and mechanisms of natural flavonoids in neuroinflammation, and the natural flavonoids might be developed into food supplements or lead compounds for neuroinflammation-associated brain disorders.

Anti-depression effectiveness of essential oil from the fruits of Zanthoxylum bungeanum maxim. on chronic unpredictable mild stress-induced depression behavior in mice

The fruits of Zanthoxylum bungeanum Maxim. Was a popular traditional Chinese herbal medicine for pain relief, itching prevention, and diarrhea relief. The fruits of Zanthoxylum bungeanum Maxim. Essential oil (HEO) had an effect of improving anxiety and other emotional disorders. In this paper, we aim to systematically research the antidepressant effects of HEO on Chronic Mild Unpredictable Stimulation (CUMS) mice and explore the relevant molecular mechanisms. Experimental mice were exposed to CUMS for 8 weeks. Meanwhile, for 8 weeks, Sertraline hydrochloride (20 mg/kg/day) and HEO (50, 100, and 150 mg/kg/day) were administered by gavage. HEO treatment increased residence time of central zone in OFT and open-arm in EPM test but decreased immobility times in FST and TST. Moreover, HEO treatment improved the levels of 5-HT, DA, NE, and BDNF, but reduced CRF and CORT levels of the HPA axis in the hippocampus. Network pharmacology predicted the possible mechanisms for the antidepressant effects of HEO by regulation of PI3K/Akt signaling pathway. The mRNA expression of PI3K and Akt were increased, and immunofluorescence results in the hippocampus indicated that HEO treatment could increase the phosphorylation of PI3K and Akt. Besides, the viability of CORT-treated PC12 cells was significantly improved by HEO treatment. The AO-EB staining, MOMP analysis, and flow cytometry analysis results showed HEO inhibiting the CORT-induced apoptosis in PC12 cells significantly. Besides, the phosphorylation of PI3K and Akt in COTR-induced PC12 cells could increase by HEO treatment. In conclusion, HEO ameliorated depression behavior induced by CUMS, potentially via regulating HPA axis and activating PI3K/Akt signaling pathway to reduce neuronal apoptosis.

Dihydroartemisinin Attenuated Intervertebral Disc Degeneration via Inhibiting PI3K/AKT and NF-κB Signaling Pathways

Intervertebral disc degeneration (IDD) is the leading cause of low back pain (LBP). However, effective therapeutic drugs for IDD remain to be further explored. Inflammatory cytokines play a pivotal role in the onset and progression of IDD. Dihydroartemisinin (DHA) has been well reported to have powerful anti-inflammatory effects, but whether DHA could ameliorate the development of IDD remained unclear. In this study, the effects of DHA on extracellular matrix (ECM) metabolism and cellular senescence were firstly investigated in nucleus pulposus cells (NPCs) under tumor necrosis factor alpha (TNFα)-induced inflammation. Meanwhile, AKT agonist sc-79 was used to determine whether DHA exerted its actions through regulating PI3K/AKT and NF-κB signaling pathways. Next, the therapeutic effects of DHA were tested in a puncture-induced rat IDD model. Finally, we detected the activation of PI3K/AKT and NF-κB signaling pathways in clinical degenerative nucleus pulposus specimens. We demonstrated that DHA ameliorated the imbalance between anabolism and catabolism of extracellular matrix and alleviated NPCs senescence induced by TNFα in vitro. Further, we illustrated that DHA mitigated the IDD progression in a puncture-induced rat model. Mechanistically, DHA inhibited the activation of PI3K/AKT and NF-κB signaling pathways induced by TNFα, which was undermined by AKT agonist sc-79. Molecular docking predicted that DHA bound to the PI3K directly. Intriguingly, we also verified the activation of PI3K/AKT and NF-κB signaling pathways in clinical degenerative nucleus pulposus specimens, suggesting that DHA may qualify itself as a promising drug for mitigating IDD.

Morinda officinalis oligosaccharides mitigate chronic mild stress-induced inflammation and depression-like behaviour by deactivating the MyD88/PI3K pathway via E2F2

Morinda officinalis oligosaccharides (MOs) are natural herbal extracts that have been shown to exert antidepressant effects. However, the mechanism of this effect remains unclear. Here, we explored the mechanism by which MOs improved experimental depression. Using a chronic mild stress (CMS) murine model, we examined whether MOs could protect against depressive-like behaviour. Lipopolysaccharide (LPS)- and ATP-treated BV2 cells were used to examine the potential mechanism by which MOs mediate the inflammatory response. We found that MOs prevented the CMS-induced reduction in the sucrose preference ratio in the sucrose preference test (SPT) and shortened the immobility durations in both the tail suspension test (TST) and forced swim test (FST). We also noticed that MOs suppressed inflammatory effects by deactivating the MyD88/PI3K pathway via E2F2 in CMS mice or LPS- and ATP-stimulated BV2 cells. Furthermore, overexpression of E2F2 blunted the beneficial effects of MOs in vitro. Collectively, these data showed that MOs exerted antidepressant effects in CMS mice by targeting E2F2-mediated MyD88/PI3K signalling pathway.

Antidepressant-like Effects of Polygonum minus Aqueous Extract in Chronic Ultra-Mild Stress-Induced Depressive Mice Model

Depression is the most common behavior disorder that leads to many disabilities. The main aim of this study was to evaluate the effects of a Polygonum minus (P. minus) aqueous extract on chronic ultra-mild stress (CUMS)-induced depressive mice model. Chronic ultra-mild stress can disturb the neurotransmitters levels and plasticity of the hippocampus. Balb/c male mice were used in this study, which consisted of six groups (n = 14). Treatment was given for eight weeks, and chronic ultra-mild stress was applied for six weeks. Commercially available P. minus extract (BioKesum®) was used in this study. The behavior and neurochemical parameters were investigated through behavioral Tests and ELISA assays. P. minus administration significantly (p < 0.05) restored CUMS-induced behavior abnormalities, decreased the immobility time, and increased the sucrose preference and increased the spatial memory. P. minus treatment also showed the decreased level of serum corticosterone and increased the level of hippocampal neurotransmitters (Serotonin and Norepinephrine) significantly (p < 0.05). The brain-derived neurotrophic factor (BDNF) level also increased significantly in both the prefrontal cortex and hippocampus (p < 0.05). P. minus treatment exhibited significant (p < 0.05) reduction of Monoamine Oxidase-A (MAO-A) in the hippocampus. These findings indicate that P. minus aqueous extract exhibits antidepressant effects, including decreased immobility time, increased spatial memory, reduced corticosterone, increased BDNF level, and reduced MAO-A enzyme level with increasing the monoamines (serotonin and norepinephrine) in the hippocampus.

Antidepressant Potential of Quercetin and its Glycoside Derivatives: A Comprehensive Review and Update

Depression is a global health problem with growing prevalence rates and serious impacts on the daily life of patients. However, the side effects of currently used antidepressants greatly reduce the compliance of patients. Quercetin is a flavonol present in fruits, vegetables, and Traditional Chinese medicine (TCM) that has been proved to have various pharmacological effects such as anti-depressant, anti-cancer, antibacterial, antioxidant, anti-inflammatory, and neuroprotective. This review summarizes the evidence for the pharmacological application of quercetin to treat depression. We clarified the mechanisms of quercetin regulating the levels of neurotransmitters, promoting the regeneration of hippocampal neurons, improving hypothalamic-pituitary-adrenal (HPA) axis dysfunction, and reducing inflammatory states and anti-oxidative stress. We also summarized the antidepressant effects of some quercetin glycoside derivatives to provide a reference for further research and clinical application.

Synergistic effects of two natural compounds of iridoids on rapid antidepressant action by up-regulating hippocampal PACAP signaling

BACKGROUND AND PURPOSE

Current mainstream antidepressants have limited efficacy and a delayed onset of action. Yueju is a traditional herbal medicine conferring rapid antidepressant activity. Here we attempted to identify the effective compounds from Yueju and the underlying mechanisms.

EXPERIMENTAL APPROACH

A transcriptomic analysis was employed to discover key candidate molecules for rapid antidepressant response. The enriched compounds in Yueju were identified with HPLC. Antidepressant effects were evaluated periodically using various behavioral paradigms. The mechanistic signaling was assessed using site-directed pharmacological intervention or optogenetic manipulation.

KEY RESULTS

A transcriptomic analysis revealed that Yueju up-regulated pituitary adenylate cyclase activating polypeptide (PACAP) expression in the hippocampus. Two iridoids geniposide (GP) and shanzhiside methyl-ester (SM) were enriched in Yueju. Co-treatment of GP and SM each at an equivalent dose in Yueju synergistically increased PACAP expression and elicited rapid antidepressant effects, which were prevented by intra-hippocampal dentate gyrus (DG) infusions of a PACAP antagonist or optogenetic inactivation of PACAP-expressing neurons. GP-SM co-treatment rapidly reduced CaMKII phosphorylation and enhanced mTOR/4EBP1/P70S6k/BDNF signaling, while intra-DG infusions of a CaMKII activator blunted rapid antidepressant effects and BDNF expression up-regulation induced by GP-SM co-treatment. A single administration of GP-SM rapidly improved depression-like behaviors and up-regulated hippocampal PACAP signaling in the repeated corticosterone-induced depression model, further confirming its rapid antidepressant action and the involvement of PACAP.

CONCLUSION AND IMPLICATIONS

GP-SM co-treatment elicited a synergistic effect on rapid antidepressant effects via triggering hippocampal PACAP activity and associated CaMKII-BDNF signaling, shedding lights on the development of novel targeted antidepressants.

Chemistry, pharmacokinetics, pharmacological activities, and toxicity of Quercitrin

Quercitrin is a naturally available type of flavonoid that commonly functions as the dietary ingredient and supplement. So far, a wide spectrum of bioactivities of quercitrin have been revealed, including antioxidative stress, antiinflammation, anti-microorganisms, immunomodulation, analgesia, wound healing, and vasodilation. Based on these various pharmacological activities, increasing studies have focused on the potency of quercitrin in diverse diseases in recent years, such as bone metabolic diseases, gastrointestinal diseases, cardiovascular and cerebrovascular diseases, and others. In this paper, by collecting and summarizing publications from the recent years, the natural sources, pharmacological activities and roles in various diseases, pharmacokinetics, structure-activity relationship, as well as the toxicity of quercitrin were systematically reviewed. In addition, the underlying molecular mechanisms of quercitrin in treating related diseases, the dose-effect relationships, and the novel preparations were discussed on the purpose of broadening the application prospect of quercitrin as functional food and providing reference for its clinical application. Notably, clinical studies of quercitrin are insufficient at present, further high-quality studies are needed to firmly establish the clinical efficacy of quercitrin.