Xiaoyaosan Improves Antibiotic-Induced Depressive-Like and Anxiety-Like Behavior in Mice Through Modulating the Gut Microbiota and Regulating the NLRP3 Inflammasome in the Colon

Xiao Yao San mitigates corticosterone stimulation-induced hippocampal neuronal damage by inhibiting GR phosphorylation and nuclear translocation via FKBP4 involvement

BACKGROUND

Corticosterone stimulation has profound physiological and neurological effects on individuals, necessitating effective interventions to mitigate its impact. Current therapeutic approaches for corticosterone stimulation injury have limitations, including addiction and tolerance issues. In contrast, historical formulations such as Xiao Yao San, a traditional Chinese medicine formula, have shown promise in addressing changes in corticosterone stimulation-related neuroplasticity. This study aimed to explore the potential of Xiao Yao San in modulating the glucocorticoid receptor (GR) signaling pathway and its downstream effects on hippocampal neuroplasticity under corticosterone stimulation conditions.

METHODS

Primary hippocampal neurons were cultured and exposed to corticosterone to establish a corticosterone stimulation model. Cellular viability, apoptosis, and protein expression were assessed via CCK-8 assays, flow cytometry, and immunoblotting, respectively. Interactions between FK506 binding protein 51 (FKBP51), GR, and p-GR were analyzed via coimmunoprecipitation and GST pull-down assays. The influence of FKBP4 on the competitive binding of GR was explored via similar techniques. The functional consequences of gene knockdown and overexpression were evaluated through cellular assays.

RESULTS

Xiao Yao San attenuated corticosterone-induced reductions in cell viability and apoptosis, counteracting the detrimental effects of corticosterone stimulation. It downregulated FKBP51 expression and suppressed GR phosphorylation and nuclear translocation. Additionally, it hindered the interaction between FKBP51 and GR/p-GR. FKBP4 overexpression rescued hippocampal neuron viability and protected against the GR phosphorylation and nuclear translocation induced by corticosterone.

CONCLUSION

Xiao Yao San exhibited promising effects in ameliorating changes in corticosterone stimulation-induced neuroplasticity through the modulation of the GR signaling pathway. By inhibiting FKBP51-mediated GR phosphorylation and nuclear translocation, Xiao Yao San has potential as an alternative therapeutic strategy for corticosterone stimulation-related conditions. Further clinical investigations and mechanistic studies are warranted to validate its therapeutic efficacy and elucidate its mechanisms of action.

Based on the Dual Pathway of Interaction-Mediated NF-κB in Cell Apoptosis and Immune Inflammation to Study the Effect of Danzhi Xiaoyao Powder on the Learning and Cognitive Ability of AD Model Rats

Background

Apoptosis and immune inflammation play important roles in the pathological process of Alzheimer's disease (AD), but their specific pathogenesis is still unclear. Therefore, this article focuses on exploring the effects of Danzhi Xiaoyao Powder (DXP) on the learning and memory ability of AD model rats from the dual mechanisms of apoptosis and immune inflammation.

Methods

The AD model was replicated by injecting Okadaic acid (100 ng) into the bilateral hippocampus of rats. Successful rats were selected and orally administered with donepezil hydrochloride and DXP decoction for 42 days. Their learning and memory abilities, hippocampal morphology, Aβ expression, inflammatory factors, apoptotic factors, anti apoptotic factors, as well as the expression of pathway proteins and mRNA were detected.

Results

After DXP intervention, the learning and memory abilities of rats improved, the neuronal cell arrangement was more complete, the expression of Aβ decreased, the expression of pro-inflammatory cytokine and apoptotic factors decreased, the expression of anti apoptotic factors increased, Protein Kinase B (Akt) expression and activity significant up-regulation, and nuclear factor kappa-B (NF-κB), p38 MAPK (p38), MAPKAPK-2 (MK2), Cyclooxygenase-2 (COX-2) protein and mRNA expression were significantly down-regulated.

Conclusion

DXP can improve the learning and cognitive abilities of AD model rats, and its mechanism of action may be related to the regulation of the Akt/NF-κB apoptosis pathway mediated by NF-κB interaction and the p38MAPK/MK2/COX-2 immune inflammatory dual pathway.

Efficacy and safety of Xiaoyao San in the treatment of chronic fatigue syndrome: a systematic review and meta-analysis

Background

Xiaoyao San (XYS) has been increasingly used in China for treating chronic fatigue syndrome (CFS), but its efficacy and safety remain unclear.

Objective

To systematically evaluate the efficacy and safety of XYS compared to standard biomedical treatments (SBT) in CFS patients.

Methods

A comprehensive search of English and Chinese databases was conducted up to December 2024. Eligible studies included randomized controlled trials comparing XYS or XYS + SBT to SBT alone. Primary outcomes were effective rate (ER) and fatigue scale-14 (FS-14). Secondary outcomes included self-rating anxiety scale (SAS), self-rating depression scale (SDS), and adverse events (AEs). Data were analyzed using Review Manager 5.4, and evidence quality was assessed using the GRADE approach.

Results

Six studies involving 623 patients were included. The meta-analysis showed that XYS-based interventions significantly improved ER (RR = 1.27, 95% CI: 1.18-1.37, I2 = 0%) and FS-14 (MD = 1.77, 95% CI: 1.49-2.06, I2 = 54%). Subgroup analyses confirmed consistent efficacy for both XYS vs. SBT and XYS + SBT vs. SBT. Anxiety and depression improved significantly in the XYS + SBT group, with SAS (MD = 5.16, 95% CI: 3.84-6.48, I2 = 24%) and SDS (MD = 4.62, 95% CI: 3.15-6.09, I2 = 0%). Additionally, the risk of AEs was significantly reduced in the XYS + SBT group compared to SBT alone (RR = 0.48, 95% CI: 0.32-0.72, I2 = 0%). However, the quality of evidence was rated "low" due to risk of bias and potential publication bias among the studies.

Conclusion

XYS, whether alone or with SBT, is effective and safe for improving ER, fatigue, anxiety, and depression in CFS patients. However, due to the low quality of the evidence, results should be interpreted cautiously. High-quality RCTs with larger sample sizes and longer follow-up are needed to provide stronger evidence for the clinical use of XYS in managing CFS.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=493084, identifier CRD42023493084.

Xiaoyaosan against depression through suppressing LPS mediated TLR4/NLRP3 signaling pathway in "microbiota-gut-brain" axis

ETHNOPHARMACOLOGICAL RELEVANCE

Depression impairs not only central nervous system, but also peripheral systems of the host. Gut microbiota have been proved to be involved in the pathogenesis of depression. Xiaoyaosan (XYS) has a history of over a thousand years in China for treating depression, dramatically alleviating anxiety, cognitive disorders, and especially gastrointestinal dysfunctions. Yet, it still just scratches the surface of the anti-depression mechanisms of XYS.

AIM OF THE STUDY

This study aims to elucidate the mechanism of actions of XYS from the perspective of "microbiota-gut-brain" axis.

MATERIALS AND METHODS

We firstly evaluated the effects of XYS on the macroscopic behaviors of depressed rats that induced by chronic unpredictable mild stress (CUMS). Secondly, the effects of XYS on intestinal homeostasis of depressed rats were revealed by using dysbacteriosis model. Subsequently, the underlying mechanisms were demonstrated by 16S rRNA gene sequencing technology and molecular biology methods. Finally, correlation analysis and visualization of the anti-depression effects of XYS were performed from the "microbiota - gut - brain" perspective.

RESULTS

Our data indicated that XYS ameliorated the depression-like symptoms of CUMS rats, partly depending on the presence of gut microbiota. Furthermore, we illustrated that XYS reversed CUMS-induced gut dysbiosis of depressed rats in terms of decreasing the Bacteroidetes/Firmicutes ratio and the abundances of Bacteroides, and Corynebacterium, while increasing the abundances of Lactobacillus and Adlercreutzia. The significant enrichment of Bacteroides and the level of lipopolysaccharides (LPS) suggested that depression damaged the immune responses and gut barrier. Mechanistically, XYS significantly down-regulated the expression levels of factors that involved in TLR4/NLRP3 signaling pathway in the colon and brain tissues of depressed rats. In addition, XYS significantly increased the levels of claudin 1 and ZO-1, showing that XYS positively maintained the integrity of gut and blood-brain barriers (BBB).

CONCLUSION

Our study offers insights into the anti-depression effects of XYS through a lens of "microbiota-TLR4/NLRP3 signaling pathway-barriers", providing a foundation for enhancing clinical efficiency and enriching drug selection, and contributing to our understanding of the mechanisms of traditional Chinese medicines (TCMs) in treating depression.

A review of antidepressant and anxiolytic effects of Soyo-san (Xiaoyao-san) and modified Soyo-san in animal models

BACKGROUND

Soyo-san (Xiaoyao-san; SYS), a traditional herbal medicine formula, has been used for treating mood disorders, especially depression and anxiety. Modified SYS (mSYS) is formulated by adding or removing herbs to SYS, and is mainly used in cases of mood disorders with comorbid diseases such as diabetes, digestive disorders, and anorexia. However, there has been no detailed comparative analysis of the differences in efficacy and underlying neurological mechanisms between SYS and mSYS.

PURPOSE

This review aimed to investigate the present scientific evidence regarding the effects of SYS and mSYS on depression and anxiety in animal models based on behavioral improvements and changes in biomarker levels.

METHODS

The PubMed, Embase, Scopus, and Medline databases were searched for all depression- and anxiety-model animal studies that used SYS and mSYS. The types of animals, methods for inducing depression or anxiety, publication trends, target diseases, types and proportions of herbs, and significant behavioral and biomolecular changes induced by SYS and mSYS treatment were analyzed.

RESULTS

A total of 1,120 studies were identified, of which 57 studies were finally included in this review. Behavioral or environmental stress was mainly used to induce depression or anxiety in rodent models. SYS treatment improved body weight, food intake, and depression- and anxiety-like behaviors. The proportions of the herbs in the original SYS formulation were mostly fixed, whereas the types and proportions of herbs used in mSYS formulations were quite diverse. mSYS had a wider range of target diseases than SYS, and it has been used not only for depression and anxiety, but also cancer and stroke. Changes in biomarker levels in the hippocampus of the brain have been studied most extensively for both SYS and mSYS. Both SYS and mSYS are reported to regulate 5-hydroxytryptamine, brain-derived neurotrophic factor, and hypothalamic-pituitary-adrenal axis-related biomolecules in the brain, as well as changes in micro-organisms and metabolite levels in the serum and intestinal environment.

CONCLUSIONS

SYS and mSYS improved depression- and anxiety-like behaviors by regulating neurotransmission, neuronal survival, and inflammation. Further research is needed to elucidate the clinical value of mSYS through various uses-related in-depth mechanistic studies.

Effects of regulating gut microbiota by electroacupuncture in the chronic unpredictable mild stress rat model

OBJECTIVE

This study aims to investigate the effect of electroacupuncture (EA) treatment on depression, and the potential molecular mechanism of EA in depression-like behaviors rats.

METHODS

A total of 40 male Sprague Dawley rats were divided into three groups: normal control, chronic unpredictable mild stress (CUMS), and EA (CUMS + EA). The rats in CUMS and EA groups underwent chronic stress for 10 weeks, and EA group rats received EA treatment for 4 weeks starting from week 7. Body weight and behavioral tests, including the sucrose preference test (SPT), the forced swimming test (FST), and the open field test (OFT) were monitored. Gut microbiota composition was assessed via 16S rDNA sequencing, and lipid metabolism was analyzed by using UPLC-Q-TOF/MS technology.

RESULTS

In comparison to CUMS group, EA could improve the behavior including bodyweight, immovability time, sucrose preference index, crossing piece index and rearing times index. After 4 weeks of EA treatment, 5-HT in hippocampus, serum and colon of depressive rats were simultaneously increased, indicating a potential alleviation of depression-like behaviors. In future studies revealed that EA could regulate the distribution and functions of gut microbiota, and improve the intestinal barrier function of CUMS rats. The regulation of intestinal microbial homeostasis by EA may further affect lipid metabolism in CUMS rats, and thus play an antidepressant role.

CONCLUSION

This study suggested that EA has potential antidepressant effects by regulating gut microbiota composition and abundance, subsequently affecting lipid metabolism.

Review on the role of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome pathway in diabetes: mechanistic insights and therapeutic implications

This review explores the pivotal role of the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome in the pathogenesis of diabetes and its complications, highlighting the therapeutic potential of various oral hypoglycemic drugs targeting this pathway. NLRP3 inflammasome activation, triggered by metabolic stressors like hyperglycemia, hyperlipidemia, and free fatty acids (FFAs), leads to the release of pro-inflammatory cytokines interleukin-1β and interleukin-18, driving insulin resistance, pancreatic β-cell dysfunction, and systemic inflammation. These processes contribute to diabetic complications such as nephropathy, neuropathy, retinopathy, and cardiovascular diseases (CVD). Here we discuss the various transcriptional, epigenetic, and gut microbiome mediated regulation of NLRP3 activation in diabetes. Different classes of oral hypoglycemic drugs modulate NLRP3 inflammasome activity through various mechanisms: sulfonylureas inhibit NLRP3 activation and reduce inflammatory cytokine levels; sodium-glucose co-transporter 2 inhibitors (SGLT2i) suppress inflammasome activity by reducing oxidative stress and modulating intracellular signaling pathways; dipeptidyl peptidase-4 inhibitors mitigate inflammasome activation, protecting against renal and vascular complications; glucagon-like peptide-1 receptor agonists attenuate NLRP3 activity, reducing inflammation and improving metabolic outcomes; alpha-glucosidase inhibitors and thiazolidinediones exhibit anti-inflammatory properties by directly inhibiting NLRP3 activation. Agents that specifically target NLRP3 and inhibit their activation have been identified recently such as MCC950, Anakinra, CY-09, and many more. Targeting the NLRP3 inflammasome, thus, presents a promising strategy for managing diabetes and its complications, with oral hypoglycemic drugs offering dual benefits of glycemic control and inflammation reduction. Further research into the specific mechanisms and long-term effects of these drugs on NLRP3 inflammasome activity is warranted.

(+)-catechin protects PC12 cells against CORT-induced oxidative stress and pyroptosis through the pathways of PI3K/AKT and Nrf2/HO-1/NF-κB

Pyroptosis induced by oxidative stress is a significant contributor to mental health disorders, including depression (+)-Catechin (CA), a polyphenolic compound prevalent in various food sources, has been substantiated by prior research to exhibit potent antioxidant properties and potential antidepressant effects. Nonetheless, the precise antidepressive mechanisms and effects of CA remain incompletely elucidated. In this study, we employed corticosterone (CORT) and PC12 cells to develop a cellular model of depression, aiming to investigate the protective effects of CA against CORT-induced cellular damage. Our objective was to elucidate the underlying mechanisms of protective action. We utilized transcriptomic analysis to identify differentially expressed genes and employed bioinformatics approaches to predict the potential mechanisms of CA's protective effects in PC12 cells. These transcriptomic predictions were subsequently validated through western blot analysis. The findings indicated that CA possesses the capacity to mitigate oxidative stress and suppress pyroptosis in PC12 cells via the activation of the PI3K/AKT signaling pathway. This activation subsequently modulates the Nrf2/HO1/NF-κB pathways, thereby providing protection to PC12 cells against damage induced by CORT. Furthermore, we investigated the interaction between CA and the Keap1 protein employing molecular docking and protein thermal shift assays. We propose that CA can activate Nrf2 through two mechanisms to decrease reactive oxygen species (ROS) levels and inhibit pyroptosis: one mechanism involves the activation of the PI3K/AKT signaling pathway, and the other involves direct binding to Keap1, leading to an increase in p-Nrf2.

Progress of research on the treatment of depression by traditional Chinese medicine prescriptions

Depression is a common psychiatric disorder that belongs to the category of "Depression Syndrome" in traditional Chinese medicine (TCM), and its etiology and pathogenesis are complex and unclear. It is characterized by high prevalence, high disability rate, and high recurrence rate, which seriously affect human health, and its treatment has become a research hotspot worldwide. At present, the antidepressants commonly used in the clinic are mainly Western medicine (WM), but there are problems such as frequent side effects and poor efficacy. Studies have found that the use of TCM prescriptions in the treatment of depression can achieve the same effect as WM; and when TCM prescriptions are combined with WM, the efficacy can be enhanced while the adverse effects of WM can be reduced. Pharmacological studies related to the treatment of depression with traditional Chinese medicine prescriptions (TCMPs) have focused on the neurobiochemical system, gut microbes, and energy metabolism in mitochondria. No one has yet reviewed the pharmacological mechanism of TCMPs for depression. So, this paper reviews the pharmacological mechanism of TCMPs for depression from the perspective of TCMPs, introduces the progress of research on classical TCMPs for depression and their antidepressant mechanism. This article aims to promote the application of TCMPs in the clinic and provide a new therapeutic idea for the clinical treatment of depression.

From Perspective of Hippocampal Plasticity: Function of Antidepressant Chinese Medicine Xiaoyaosan

The hippocampus is one of the most commonly studied brain regions in the context of depression. The volume of the hippocampus is significantly reduced in patients with depression, which severely disrupts hippocampal neuroplasticity. However, antidepressant therapies that target hippocampal neuroplasticity have not been identified as yet. Chinese medicine (CM) can slow the progression of depression, potentially by modulating hippocampal neuroplasticity. Xiaoyaosan (XYS) is a CM formula that has been clinically used for the treatment of depression. It is known to protect Gan (Liver) and Pi (Spleen) function, and may exert its antidepressant effects by regulating hippocampal neuroplasticity. In this review, we have summarized the association between depression and aberrant hippocampal neuroplasticity. Furthermore, we have discussed the researches published in the last 30 years on the effects of XYS on hippocampal neuroplasticity in order to elucidate the possible mechanisms underlying its therapeutic action against depression. The results of this review can aid future research on XYS for the treatment of depression.

Gut microbiota and its metabolites in Alzheimer's disease: from pathogenesis to treatment

Introduction

An increasing number of studies have demonstrated that altered microbial diversity and function (such as metabolites), or ecological disorders, regulate bowel-brain axis involvement in the pathophysiologic processes in Alzheimer's disease (AD). The dysregulation of microbes and their metabolites can be a double-edged sword in AD, presenting the possibility of microbiome-based treatment options. This review describes the link between ecological imbalances and AD, the interactions between AD treatment modalities and the microbiota, and the potential of interventions such as prebiotics, probiotics, synbiotics, fecal microbiota transplantation, and dietary interventions as complementary therapeutic strategies targeting AD pathogenesis and progression.

Survey methodology

Articles from PubMed and china.com on intestinal flora and AD were summarized to analyze the data and conclusions carefully to ensure the comprehensiveness, completeness, and accuracy of this review.

Conclusions

Regulating the gut flora ecological balance upregulates neurotrophic factor expression, regulates the microbiota-gut-brain (MGB) axis, and suppresses the inflammatory responses. Based on emerging research, this review explored novel directions for future AD research and clinical interventions, injecting new vitality into microbiota research development.

Gut dysbiosis induces the development of depression-like behavior through abnormal synapse pruning in microglia-mediated by complement C3

BACKGROUND

Remodeling eubiosis of the gut microenvironment may contribute to preventing the occurrence and development of depression. Mounting experimental evidence has shown that complement C3 signaling is associated with the pathogenesis of depression, and disruption of the gut microbiota may be an underlying cause of complement system activation. However, the mechanism by which complement C3 participates in gut-brain crosstalk in the pathogenesis of depression remains unknown.

RESULTS

In the present study, we found that chronic unpredictable mild stress (CUMS)-induced mice exhibited obvious depression-like behavior as well as cognitive impairment, which was associated with significant gut dysbiosis, especially enrichment of Proteobacteria and elevation of microbiota-derived lipopolysaccharides (LPS). In addition, peripheral and central complement C3 activation and central C3/CR3-mediated aberrant synaptic pruning in microglia have also been observed. Transplantation of gut microbiota from CUMS-induced depression model mice into specific pathogen-free and germ-free mice induced depression-like behavior and concomitant cognitive impairment in the recipient mice, accompanied by increased activation of the complement C3/CR3 pathway in the prefrontal cortex and abnormalities in microglia-mediated synaptic pruning. Conversely, antidepressants and fecal microbiota transplantation from antidepressant-treated donors improved depression-like behaviors and restored gut microbiome disturbances in depressed mice. Concurrently, inhibition of the complement C3/CR3 pathway, amelioration of abnormal microglia-mediated synaptic pruning, and increased expression of the synapsin and postsynaptic density protein 95 were observed. Collectively, our results revealed that gut dysbiosis induces the development of depression-like behaviors through abnormal synapse pruning in microglia-mediated by complement C3, and the inhibition of abnormal synaptic pruning is the key to targeting microbes to treat depression.

CONCLUSIONS

Our findings provide novel insights into the involvement of complement C3/CR3 signaling and aberrant synaptic pruning of chemotactic microglia in gut-brain crosstalk in the pathogenesis of depression. Video Abstract.

Polyphenols in edible herbal medicine: targeting gut-brain interactions in depression-associated neuroinflammation

Supplementing with edible herbal medicine is an important strategy because of its role in nutrition. Many polyphenols, which are universal components in edible herbal medicines, have low bioavailability. Therefore, gut microbiota is a key determinant of polyphenol bioactivity. Polyphenols can alter the abundance of flora associated with neuroinflammation by reversing intestinal microbiota dysbiosis. Intestinal flora-mediated chemical modification of polyphenols can result in their conversion into active secondary metabolites. The current review summarizes the main edible medicines used in anti-depression and details the interactions between polyphenols and gut microbiota; in addition, it provides insights into the mechanisms underlying the possible suppression of neuroinflammation associated with depression, by polyphenols in edible herbal medicine. A better understanding of polyphenols with bioactivities that are crucial in edible herbal medicine may facilitate their use in the prevention and treatment of neuroinflammation associated with depression.

The gut-lung axis in influenza A: the role of gut microbiota in immune balance

Influenza A, the most common subtype, induces 3 to 5 million severe infections and 250,000 to 500,000 deaths each year. Vaccination is traditionally considered to be the best way to prevent influenza A. Yet because the Influenza A virus (IAV) is highly susceptible to antigenic drift and Antigenic shift, and because of the lag in vaccine production, this poses a significant challenge to vaccine effectiveness. Additionally, much information about the resistance of antiviral drugs, such as Oseltamivir and Baloxavir, has been reported. Therefore, the search for alternative therapies in the treatment of influenza is warranted. Recent studies have found that regulating the gut microbiota (GM) can promote the immune effects of anti-IAV via the gut-lung axis. This includes promoting IAV clearance in the early stages of infection and reducing inflammatory damage in the later stages. In this review, we first review the specific alterations in GM observed in human as well as animal models regarding IAV infection. Then we analyzed the effect of GM on host immunity against IAV, including innate immunity and subsequent adaptive immunity. Finally, our study also summarizes the effects of therapies using probiotics, prebiotics, or herbal medicine in influenza A on intestinal microecological composition and their immunomodulatory effects against IAV.

Cefaclor causes vagus nerve-mediated depression-like symptoms with gut dysbiosis in mice

Antibiotics are increasingly recognized as causing neuropsychiatric side effects including depression and anxiety. Alterations in central serotonin and 5-HT receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with gastrointestinal disorders. Nevertheless, it is still unclear how antibiotics can cause anxiety and depression. In this study, oral administration of cefaclor, a second-generation cephalosporin antibiotic, induced anxiety- and depression-like behaviors and colitis with gut microbiota alteration in mice. Cefaclor reduced serotonin levels and fluctuated 5-HT receptor mRNA expressions such as Htr1a, Htr1b, and Htr6 in the hippocampus. Vagotomy attenuated the cefaclor-induced anxiety- and depression-like symptoms, while the cefaclor-induced changes in gut bacteria alteration and colitis were not affected. Fluoxetine attenuated cefaclor-induced anxiety- and depression-like behaviors. Furthermore, fluoxetine decreased cefaclor-resistant Enterobacteriaceae and Enterococcaceae. Taken together, our findings suggest that the use of antibiotics, particularly, cefaclor may cause gut dysbiosis-dependent anxiety and depression through the microbiota-gut-blood-brain and microbiota-gut-vagus nerve-brain pathway. Targeting antibiotics-resistant pathogenic bacteria may be a promising therapeutic strategy for the treatment of anxiety and depression.

Traditional Chinese medicine for the treatment of Alzheimer's disease: A focus on the microbiota-gut-brain axis

Alzheimer's disease (AD), the most frequent cause of dementia, is a neurodegenerative disorder characterised by a progressive decline in cognitive function that is associated with the formation of amyloid beta plaques and neurofibrillary tangles. Gut microbiota comprises of a complex community of microorganisms residing in the gastrointestinal ecosystem. These microorganisms can participate in gut-brain axis activities, thereby affecting cognitive function and associated behaviours. Increasing evidence has indicated that gut dysbiosis can jeopardise host immune responses and promote inflammation, which may be an initiating factor for the onset and evolution of AD. Traditional Chinese medicine (TCM) is a promising resource which encompasses immense chemical diversity and multiple-target characteristics for the treatment of AD. Many TCMs regulate the gut microbiota during treatment of diseases, indicating that gut microbiota may be an important target for TCM efficacy. In this review, we summarised the role of the microbiota-gut-brain axis in the development of AD and the effects of TCM in treating AD by regulating the gut microbiota. We anticipate that this review will provide novel perspectives and strategies for future AD research and treatments.

Antibiotic-induced gut dysbiosis and cognitive, emotional, and behavioral changes in rodents: a systematic review and meta-analysis

There are previous epidemiological studies reporting associations between antibiotic use and psychiatric symptoms. Antibiotic-induced gut dysbiosis and alteration of microbiota-gut-brain axis communication has been proposed to play a role in this association. In this systematic review and meta-analysis, we reviewed published articles that have presented results on changes in cognition, emotion, and behavior in rodents (rats and mice) after antibiotic-induced gut dysbiosis. We searched three databases-PubMed, Web of Science, and SCOPUS to identify such articles using dedicated search strings and extracted data from 48 articles. Increase in anxiety and depression-like behavior was reported in 32.7 and 40.7 percent of the study-populations, respectively. Decrease in sociability, social novelty preference, recognition memory and spatial cognition was found in 18.1, 35.3, 26.1, and 62.5 percent of the study-populations, respectively. Only one bacterial taxon (increase in gut Proteobacteria) showed statistically significant association with behavioral changes (increase in anxiety). There were no consistent findings with statistical significance for the potential biomarkers [Brain-derived neurotrophic factor (BDNF) expression in the hippocampus, serum corticosterone and circulating IL-6 and IL-1β levels]. Results of the meta-analysis revealed a significant association between symptoms of negative valence system (including anxiety and depression) and cognitive system (decreased spatial cognition) with antibiotic intake (p < 0.05). However, between-study heterogeneity and publication bias were statistically significant (p < 0.05). Risk of bias was evaluated to be high in the majority of the studies. We identified and discussed several reasons that could contribute to the heterogeneity between the results of the studies examined. The results of the meta-analysis provide promising evidence that there is indeed an association between antibiotic-induced gut dysbiosis and psychopathologies. However, inconsistencies in the implemented methodologies make generalizing these results difficult. Gut microbiota depletion using antibiotics may be a useful strategy to evaluate if and how gut microbes influence cognition, emotion, and behavior, but the heterogeneity in methodologies used precludes any definitive interpretations for a translational impact on clinical practice.

Research on Xiaoyao Powder in the treatment of depression based on epigenetics and quality markers

Depression has become one of the most common public health issues around the world, and the incidence has been increasing in recent years. A large amount of clinical investigations have proven that the treatment of depression is difficult. The prognosis is poor, and the fatality rate is high. At present, western medicine is the preferred treatment for depression, but it often causes adverse clinical reactions such as dry mouth, blurred vision, and memory loss, etc. The herbal compound Xiaoyao Powder is a traditional medicine for soothing the liver and relieving depression, strengthening the spleen, and nourishing the blood. It can reduce adverse reactions. It is effective in treating depression. In this study, we elucidate the function of Xiaoyao Powder in anti-depression from the perspective of clinical application and pharmacological mechanisms such as regulating epigenetic and chemical quality markers to provide empirical and experimental theoretical results that contribute to developing future depression therapy with Xiaoyao Powder.

The Role of Gut Microbiota in Anxiety, Depression, and Other Mental Disorders as Well as the Protective Effects of Dietary Components

The number of individuals experiencing mental disorders (e.g., anxiety and depression) has significantly risen in recent years. Therefore, it is essential to seek prevention and treatment strategies for mental disorders. Several gut microbiota, especially Firmicutes and Bacteroidetes, are demonstrated to affect mental health through microbiota-gut-brain axis, and the gut microbiota dysbiosis can be related to mental disorders, such as anxiety, depression, and other mental disorders. On the other hand, dietary components, including probiotics (e.g., Lactobacillus and Bifidobacterium), prebiotics (e.g., dietary fiber and alpha-lactalbumin), synbiotics, postbiotics (e.g., short-chain fatty acids), dairy products, spices (e.g., Zanthoxylum bungeanum, curcumin, and capsaicin), fruits, vegetables, medicinal herbs, and so on, could exert protective effects against mental disorders by enhancing beneficial gut microbiota while suppressing harmful ones. In this paper, the mental disorder-associated gut microbiota are summarized. In addition, the protective effects of dietary components on mental health through targeting the gut microbiota are discussed. This paper can be helpful to develop some dietary natural products into pharmaceuticals and functional foods to prevent and treat mental disorders.

A whole transcriptome profiling analysis for antidepressant mechanism of Xiaoyaosan mediated synapse loss via BDNF/trkB/PI3K signal axis in CUMS rats

BACKGROUND

Depression is a neuropsychiatric disease resulting from deteriorations of molecular networks and synaptic injury induced by stress. Traditional Chinese formula Xiaoyaosan (XYS) exert antidepressant effect, which was demonstrated by a great many of clinical and basic investigation. However, the exact mechanism of XYS has not yet been fully elucidated.

METHODS

In this study, chronic unpredictable mild stress (CUMS) rats were used as a model of depression. Behavioral test and HE staining were used to detect the anti-depressant effects of XYS. Furthermore, whole transcriptome sequencing was employed to establish the microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA (circRNA), and mRNA profiles. The biological functions and potential mechanisms of XYS for depression were gathered from the GO and KEGG pathway. Then, constructed the competing endogenous RNA (ceRNA) networks to illustrate the regulatory relationship between non-coding RNA (ncRNA) and mRNA. Additionally, longest dendrite length, total length of dendrites, number of intersections, and density of dendritic spines were detected by Golgi staining. MAP2, PSD-95, SYN were detected by immunofluorescence respectively. BDNF, TrkB, p-TrkB, PI3K, Akt, p-Akt were measured by Western Blotting.

RESULTS

The results showed that XYS could increase the locomotor activity and sugar preference, decreased swimming immobility time as well as attenuate hippocampal pathological damage. A total of 753 differentially expressed lncRNAs (DElncRNAs), 28 circRNAs (DEcircRNAs), 101 miRNAs (DEmiRNAs), and 477 mRNAs (DEmRNAs) were identified after the treatment of XYS in whole transcriptome sequencing analysis. Enrichment results revealed that XYS could regulate multiple aspects of depression through different synapse or synaptic associated signal, such as neurotrophin signaling and PI3K/Akt signaling pathways. Then, vivo experiments indicated that XYS could promote length, density, intersections of synapses and also increase the expression of MAP2 in hippocampal CA1, CA3 regions. Meanwhile, XYS could increase the expression of PSD-95, SYN in the CA1, CA3 regions of hippocampal by regulating the BDNF/trkB/PI3K signal axis.

CONCLUSION

The possible mechanism on synapse of XYS in depression was successfully predicted. BDNF/trkB/PI3K signal axis were the potential mechanism of XYS on synapse loss for its antidepressant. Collectively, our results provided novel information about the molecular basis of XYS in treating depression.

Gut microbiota decreased inflammation induced by chronic unpredictable mild stress through affecting NLRP3 inflammasome

Dysbiosis of the gut microbiota is associated with the development of depression, but the underlying mechanism remains unclear. The aim of this study was to determine the relationship between microbiota and NLRP3 inflammasome induced by chronic unpredictable mild stress (CUMS). Fecal transplantation (FMT) experiment was conducted to elucidate the potential mechanism. Levels of NLRP3 inflammasome, microbiota, inflammatory factors and tight junction proteins were measured. CUMS stimulation significantly increased the levels of NLRP3, Caspase-1 and ASC in brain and colon(p<0.05), decreased the levels of tight junction proteins Occludin and ZO-1 (p<0.05). Interestingly, increased NLRP3 inflammasome and inflammatory cytokines and decreased tight junction proteins were found in antibiotic-treated (Abx) rats received CUMS rat fecal microbiota transplantation. Furthermore, fecal microbiota transplantation altered the microbiota in Abx rats, which partially overlapped with that of the donor rats. Importantly, probiotic administration amended the alteration of microbiota induced by CUMS treatment, then reduced the levels of NLRP3 inflammasome and inflammatory factors. In conclusion, these findings suggested that depression-like behaviors induced by CUMS stimulation were related to altered gut microbiota, broke the intestinal barrier, promoted the expression of NLRP3 inflammasome and elevated inflammation. Therefore, improving the composition of microbiota via probiotic can attenuate inflammation by amending the microbiota and suppressing the activation of NLRP3 inflammasome, which is considered as a novel therapeutic strategy for depression.

Gut Microbiota in Anxiety and Depression: Unveiling the Relationships and Management Options

The gut microbiota is critical for maintaining human health and the immunological system. Several neuroscientific studies have shown the significance of microbiota in developing brain systems. The gut microbiota and the brain are interconnected in a bidirectional relationship, as research on the microbiome-gut-brain axis shows. Significant evidence links anxiety and depression disorders to the community of microbes that live in the gastrointestinal system. Modified diet, fish and omega-3 fatty acid intake, macro- and micro-nutrient intake, prebiotics, probiotics, synbiotics, postbiotics, fecal microbiota transplantation, and 5-HTP regulation may all be utilized to alter the gut microbiota as a treatment approach. There are few preclinical and clinical research studies on the effectiveness and reliability of various therapeutic approaches for depression and anxiety. This article highlights relevant research on the association of gut microbiota with depression and anxiety and the different therapeutic possibilities of gut microbiota modification.

Gut microbiota-SCFAs-brain axis associated with the antidepressant activity of berberine in CUMS rats

BACKGROUND

The anti-depressant effect of berberine (BBR) has been widely reported. However, the underlying mechanism remains unclear. The microbiota-gut-brain (MGB) axis plays a key role in the pathogenesis of depression. Therefore, we aimed to explore the anti-depressant mechanisms of BBR involving the association of the gut microbiota, neurotransmitters, BDNF, and SCFAs in chronic unpredictable mild stress (CUMS)-induced depressive rats.

METHODS

The antidepressant effects of BBR were detected by open-field test, 1 % sucrose preference test and body weight test in CUMS-induced depressive rats. 16S rDNA sequencing was performed to identify the change of gut microbiota. The concentrations of fecal SCFAs were analyzed by GC-MS targeted metabolomics. At the same time, neurotransmitters and BDNF expression were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

BBR improved depression-like behaviors in CUMS rats by increasing the expression of serotonin (5-HT), norepinephrine (NE), dopamine (DA), and BDNF in the hippocampus. BBR regulates Firmicutes, Bacteroidetes, and Lachnospiraceae in depressive rats, resulting in the alteration of the synthesis and metabolism of SCFAs, including acetic, propanoic, and isovaleric acids.

LIMITATIONS

Direct evidence that BBR improves depressive behaviors via gut microbiota-SCFAs-brain axis is lacking, and only male rats were investigated in the present study.

CONCLUSION

The anti-depressant mechanism of BBR is related to the regulation of the MGB axis via modulating the gut microbiota-SCFAs-monoamine neurotransmitters/BDNF.

Interactions Between Antidepressants and Intestinal Microbiota

The microbiota-gut-brain axis has been shown to influence human health and diseases, including depression. The interactions between drugs and intestinal microbiota are complex and highly relevant to treat diseases. Studies have shown an interaction between antidepressants and intestinal microbiota. Antidepressants may alter the abundance and composition of intestinal microbiota, which are closely related to the treatment outcomes of depression. Intestinal microbiota can influence the metabolism of antidepressants to change their availability (e.g., tryptophan can be metabolized to kynurenine by intestinal microbiota) and regulate their absorption by affecting intestinal permeability. In addition, the permeability of the blood-brain barrier can be altered by intestinal microbiota, influencing antidepressants to reach the central nervous system. Bioaccumulation is also a type of drug-microbiota interaction, which means bacteria accumulate drugs without biotransformation. These findings imply that it is important to consider intestinal microbiota when evaluating antidepressant therapy regimens and that intestinal microbiota can be a potential target for depression treatment.

A systematic review of the effects of gut microbiota depletion on social and anxiety-related behaviours in adult rodents: Implications for translational research

The microbiota-gut-brain axis is associated with several behaviours, including those relevant to anxiety or sociability in rodents, however, no conceptual framework has yet been available. Summary of the effects of antibiotic-mediated gut microbiota depletion on anxiety and sociability is essential to both inform further preclinical investigations and to guide translational research into human studies. The main objective is to examine the role of gut microbiota depletion on anxiety and sociability in rodents, and to consider how the findings can be translated to inform the design of research in humans. We reviewed 13 research articles, indicating significant changes in gut microbiota composition and diversity have been found in animals treated with a mix or a single antibiotic. Nonetheless, there is no consensus regarding the impact of gut microbiota depletion on anxiety-like or social behaviour. Gut microbiota depletion may be a useful strategy to examine the role of gut microbes in anxiety and sociability, but the lack of data from rigorous animal investigations precludes any definitive interpretations for a translational impact on human health.

Antidepressant effects of the traditional Chinese herbal formula Xiao-Yao-San and its bioactive ingredients

BACKGROUND

Depression is one of the most debilitating and severe psychiatric disorders and a serious public health concern. Currently, many treatments are indicated for depression, including traditional Chinese medicinal formulae such as Xiao-Yao-San (XYS), which has effective antidepressant effects in clinical and animal studies.

PURPOSE

To summarize current evidence of XYS in terms of the preclinical and clinical studies and to identify the multi-level, multi-approach, and multi-target potential antidepressant mechanisms of XYS and active components of XYS by a comprehensive search of the related electronic databases.

METHODS

The following electronic databases were searched from the beginning to April 2022: PubMed, MEDLINE, Web of Science, Google Scholar, and China National Knowledge Infrastructure.

RESULTS

This review summarizes the antidepressant mechanisms of XYS and its active ingredients, which are reportedly correlated with monoamine neurotransmitter regulation, synaptic plasticity, and hypothalamic-pituitary-adrenal axis, etc. CONCLUSION: XYS plays a critical role in the treatment of depression by the regulation of several factors, including the monoaminergic systems, hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, brain-gut axis, and other pathways. However, more clinical and animal studies should be conducted to further investigate the antidepressant function of XYS and provide more evidence and recommendations for its clinical application. Our review provides an overview of XYS and guidance for future research direction.

Network Pharmacology and Experimental Validation to Investigate the Antidepressant Potential of Atractylodes lancea (Thunb.) DC

Atractylodes lancea (Thunb.) DC. (AL) has been indicated in traditional prescriptions for the treatment of depression. However, the mechanism of action of AL in the treatment of depression is still unclear. This study aimed to investigate the antidepressant potential of AL using network pharmacology, molecular docking, and animal experiments. The active components of AL were retrieved from the traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP), and the depression-related targets were screened through the DisGeNET database. Overlapping targets of AL and depression were selected and analyzed. Ten active compounds of AL showed anti-depressant potential, including stigmasterol, 3β-acetoxyatractylone, wogonin, β-sitosterol, selina-4(14),7(11)-dien-8-one, atractylenolide I, atractylenolide II, atractylenolide III, patchoulene, and cyperene. These compounds target 28 potential antidepressant genes/proteins. Gene Ontology (GO) enrichment analysis revealed that the potential targets might directly influence neural cells and regulate neuroinflammation and neurotransmitter-related processes. The potential Kyoto Encyclopedia Genes and Genomes (KEGG) pathways for the antidepressant effects of AL include neuroactive ligand-receptor interactions, calcium signaling pathways, dopaminergic synapse, interleukin (IL)-17 signaling pathways, and the pathways of neurodegeneration. IL-6, nitric oxide synthase 3 (NOS), solute carrier family 6 member 4 (SLC6A4), estrogen receptor (ESR1), and tumor necrosis factor (TNF) were the most important proteins in the protein-protein interaction network and these proteins showed high binding affinities with the corresponding AL compounds. AL showed an antidepressant effect in mice by decreasing immobility time in the tail suspension test and increasing the total contact number in the social interaction test. This study demonstrated the antidepressant potential of AL, which provides evidence for pursuing further studies to develop a novel antidepressant.

Gut microbiota: An emerging therapeutic approach of herbal medicine for prevention of colorectal cancer

The gut dysbiosis has emerged as a prominent player in the pathogenesis and development of colorectal cancer (CRC), which in turn intensifies dysregulated gut microbiota composition and inflammation. Since most drugs are given orally, this dysbiosis directly and indirectly impinges the absorption and metabolism of drugs in the gastrointestinal tract, and subsequently affects the clinical outcome of patients with CRC. Herbal medicine, including the natural bioactive products, have been used traditionally for centuries and can be considered as novel medicinal sources for anticancer drug discovery. Due to their various structures and pharmacological effects, natural products have been found to improve microbiota composition, repair intestinal barrier and reduce inflammation in human and animal models of CRC. This review summarizes the chemo-preventive effects of extracts and/or compounds derived from natural herbs as the promising antineoplastic agents against CRC, and will provide innovative strategies to counteract dysregulated microbiota and improve the lives of CRC patients.

Research progress on classical traditional chinese medicine formula xiaoyaosan in the treatment of depression

Depression is an emotional disorder that is problematic in psychiatry owing to its unclear etiology and unknown pathogenesis. Traditional Chinese medicine formulations such as Xiaoyaosan have been widely used throughout history to treat depression. In this review, we have focused on recent evidences elucidating the links between Xiaoyaosan and the treatment of depression. Data from animal and clinical studies, focusing on the pharmacological mechanisms, clinical applications, and effective materials that form the basis for the treatment of depression are presented and discussed. We found that the antidepressant effects of Xiaoyaosan are related to the effects of monoamine neurotransmitters, regulation of the hypothalamic-pituitary-adrenal axis, neuroplasticity, synaptic plasticity, inflammatory response, neuroprotection, brain-gut axis, regulation of intestinal microbiota, oxidative stress, and autophagy for reducing neuronal apoptosis. This review highlights the current evidence supporting the use of Xiaoyaosan as an antidepressant and provides an overview of the potential mechanisms involved.

Xiaoyaosan inhibits neuronal apoptosis by regulating the miR-200/NR3C1 signaling in the prefrontal cortex of chronically stressed rats

BACKGROUND

Depression is a prevalent emotion disorder which is thought to be due to neuronal structural alterations and/or functional impairment within specific brain regions. Several studies have shown that microRNAs are involved in the pathogenesis of depression. As a Chinese herbal formula, Xiaoyaosan (XYS) could have antidepressive effects, although the mechanisms associated with microRNAs are poorly understood.

PURPOSE

In this study, we investigated whether inhibition of the miR-200a/b-3p/NR3C1 pathway in the prefrontal cortex is involved in the anti-neuronal apoptosis and anti-stress effects of XYS and then further delineated the underlying mechanism.

METHODS

To evaluate the efficacy of XYS in relieving stress behaviors and altering the expression of miRNAs involved in the regulation of these behaviors in vivo, a chronic unpredictable mild stress (CUMS) rodent model and RNA-seq were performed. Primary cortical neurons were used to evaluate the molecular function of miR-200a/b-3p and detect the in vitro neuroprotective function of paeoniflorin, which is one of the main components of XYS. To investigate the function of miR-200a/b-3p in stress behaviors, stereotactic microinjection of AAV2/9-Syn-miR-200a/b-3p was performed to deliver the treatment to the rat mPFC.

RESULTS

XYS reduced the anxiety and depression-like behaviors associated with chronic stress and reduced the expression of miR-200a/b-3p and neuronal apoptosis in the prefrontal cortex (PFC). The overexpression of miR-200a/b-3p in primary cortical neurons reduced the expression of the target gene NR3C1, increased the protein expression of cleaved caspase-3 and Bax, and decreased the anti-apoptotic protein Bcl-2. One of the active ingredients of XYS, paeoniflorin, can inhibit miR-200a/b-3p-mediated apoptosis of primary neurons and abnormal expression of apoptosis-related proteins. After overexpressing miR-200a/b-3p in vivo (vmPFC), the rats eventually showed significant anxiety-like behaviors similar to those caused by chronic stress.

CONCLUSION

Our findings indicate that XYS can inhibit the CUMS-induced expression of miR-200a/b-3p, regulate miR-200a/b-3p/NR3C1 signaling in the PFC caused by chronic stress, and reduce neuronal apoptosis and stress-related behaviors.

Xiaoyaosan Ameliorates Chronic Restraint Stress-Induced Depression-Like Phenotype by Suppressing A2AR Signaling in the Rat Striatum

Depression is a common mental disorder characterized by pessimism and world-weariness. In our previous study, we found that Xiaoyaosan (XYS) could have antidepressive effects, however the underlying mechanisms remain unclear. Several studies have shown that adenosine A (2 A) receptor (A2AR) in the brain is a key point in the treatment of depression. Our present study aimed to investigate the effects of XYS on A2AR signaling in the striatum of rats exposed to chronic restraint stress (CRS). Ninety-six male Sprague–Dawley rats were randomly divided into 8 groups (control, model, negative control, XYS, A2AR antagonist, A2AR antagonist + XYS, A2AR agonist, A2AR agonist + XYS). The rats in the model group, XYS group, A2AR antagonist group and A2AR antagonist + XYS group were subjected to CRS for 3 h a day. The XYS decoction [2.224 g/(kg·d)] was intragastrical administered by oral gavage to the rats in the negative control group, XYS group, A2AR antagonist + XYS group, and A2AR agonist + XYS group. The rats in the A2AR antagonist group and A2AR antagonist + XYS group were treated with SCH 58261 [0.05 mg/(kg·d)], and the rats in the A2AR agonist and A2AR agonist + XYS group were treated with CGS 21680 [0.1 mg/(kg·d)]. These procedures were performed for 21 consecutive days. Behavioral studies including the open field test, elevated plus maze test, sucrose preference test and forced swimming test, were performed to examine depression-like phenotypes. Then, the effects of XYS on CRS- or A2AR agonist-induced striatal subcellular damage, microglial activation and A2AR signaling changes in the striatum were examined. Here, we report that XYS ameliorates depression-like phenotypes (such as body weight loss as well as depression- and anxiety-like behaviors) and improves synaptic survival and growth in the stratum of the CRS rats. Moreover, XYS reduces A2AR activity and suppresses hyper-activation of striatal microglia. The tissue and cellular effects of XYS were similar to those of the known A2AR antagonists. In conclusion, XYS alleviates depression in the CRS rats via inhibiting A2AR in the striatum.

Xiaoyaosan Exerts Antidepressant-Like Effect by Regulating Autophagy Involves the Expression of GLUT4 in the Mice Hypothalamic Neurons

Many studies have proven that autophagy plays a pivotal role in the development of depression and it also affects the expression of GLUT4 in the hypothalamus. Xiaoyaosan has been shown to exert antidepressant effects in a variety of ways, but its underlying mechanism by which Xiaoyaosan regulates autophagy as well as GLUT4 in the hypothalamus remains unclear. Thus, in this study, we established a mouse model of depression induced by chronic unpredictable mild stress (CUMS), and set up autophagy blockade as a control to explore whether Xiaoyaosan exerts antidepressant effect by affecting autophagy. We examined the effects of Xiaoyaosan on behaviors exhibited during the open field test, tail suspension test and sucrose preference test, and the changes in autophagy in hypothalamic neurons as well as changes in GLUT4 and the related indicators of glucose metabolism in CUMS-induced depressive mouse model. We found that CUMS- and 3-MA-induced mice exhibited depressive-like behavioral changes, with decreased LC3 expression and increased p62 expression, suggesting decreased levels of autophagy in the mouse hypothalamus. The expression of GLUT4 was also decreased, and it was closely related to the level of autophagy through Rab8 and Rab10. Nevertheless, after the intervention of Xiaoyaosan, the above changes were effectively reversed. These results show that Xiaoyaosan can regulate the autophagy in hypothalamic neurons and the expression of GLUT4 in depressed mice.

NLRP3-Dependent Pyroptosis: A Candidate Therapeutic Target for Depression

Depression, a major public health problem, imposes a significant economic burden on society. Recent studies have gradually unveiled the important role of neuroinflammation in the pathogenesis of depression. Pyroptosis, a programmed cell death mediated by Gasdermins (GSDMs), is also considered to be an inflammatory cell death with links to inflammation. Pyroptosis has emerged as an important pathological mechanism in several neurological diseases and has been found to be involved in several neuroinflammatory-related diseases. A variety of chemical agents and natural products have been found to be capable of exerting therapeutic effects by modulating pyroptosis. Studies have shown that depression is closely associated with pyroptosis and the induced neuroinflammation of relevant brain regions, such as the hippocampus, amygdala, prefrontal cortex neurons, etc., in which the nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome plays a crucial role. This article provides a timely review of recent findings on the activation and regulation of pyroptosis in relation to depression.

The therapeutic potential of traditional Chinese medicine in depression: Targeting adult hippocampal neurogenesis

BACKGROUND

Depression is a common mental disorder characterized by persistent sadness and lack of interest or pleasure in previously rewarding or enjoyable activities. Understandably, the causes of depression are complex. Nevertheless, the understanding of depression pathophysiology has progressed considerably and numerous studies indicate that hippocampal neurogenesis plays a pivotal role. However, no drugs specifically targeting hippocampal neurogenesis yet exist. Meanwhile, the effects of traditional Chinese medicine (TCM) on hippocampal neurogenesis have received increasing attention in the field of antidepressant treatment because of its multi-ingredient, multi-target, and holistic view. However, the effects and mechanisms of TCM on hippocampal neurogenesis in clinical trials and pharmaceutical studies remain to be comprehensively delineated.

PURPOSE

To summarize the importance of hippocampal neurogenesis in depression and illustrate the targets and mechanisms of hippocampal neurogenesis regulation that underlie the antidepressant effects of TCM.

METHOD

A systematic review of clinical trials and studies ending by January 2022 was performed across eight electronic databases (Web of Science, PubMed, SciFinder, Research Gate, ScienceDirect, Google Scholar, Scopus and China Knowledge Infrastructure) according to the PRISMA criteria, using the search terms 'traditional Chinese medicine' "AND" 'depression' "OR" 'hippocampal neurogenesis' "OR" 'multi-ingredient' "OR" 'multi-target'.

RESULTS

Numerous studies show that hippocampal neurogenesis is attenuated in depression, and that antidepressants act by enhancing hippocampal neurogenesis. Moreover, compound Chinese medicine (CCM), Chinese meteria medica (CMM), and major bioactive components (MBCs) can promote hippocampal neurogenesis exerting antidepressant effects through modulation of neurotransmitters and receptors, neurotrophins, the hypothalamic-pituitary-adrenal axis, inflammatory factors, autophagy, and gut microbiota.

CONCLUSION

We have comprehensively summarized the effect and mechanism of TCM on hippocampal neurogenesis in depression providing a unique perspective on the use of TCM in the antidepressant field. TCM has the characteristics and advantages of multiple targets and high efficacy, showing great potential in the field of depression treatment.

Alterations in gut microbiota and elevated serum bilirubin in primary biliary cholangitis patients treated with ursodeoxycholic acid

BACKGROUND

The prognosis of primary bile cholangitis (PBC) is linked to gut microbiota dysbiosis. This study investigated the association between the gut microbiome and elevated total bilirubin (TB) level in PBC patients treated with ursodeoxycholic acid (UCDA).

METHODS

A total of 47 PBC patients with 12 months of UCDA treatment were enrolled. Patients were divided into the TB (+) (TB>1× upper limit of the normal range [ULN]; n = 20) and TB(-) (TB≤1× ULN; n = 27) groups. Stool and serum specimens were collected, and microbiota composition and functional characteristics in the 2 groups were evaluated by 16S RNA gene sequencing and bioinformatic analysis.

RESULTS

Bacterial diversity was lower in the TB(+) group than in the TB(-) group, although there was no significant difference in bacterial community profile. The phylum Saccharibacteria showed differential abundance in the 2 groups. Meanwhile, the TB(-) group had lower abundance of the Gemmiger, Blautia, Anaerostipes and Coprococcus genera than the TB(+) group, whereas Holdemania was absent. The abundance of Gemmiger formicillis and Coprococcus eutactus was positively correlated with that of Faecalibacterium prausnitzii, while Blautia, Anaerostipes and Coprococcus were negatively correlated with total bile acid level.

CONCLUSION

TB level in PBC patients treated for 12 months with UCDA is associated with a distinct gut microbiome profile.

Shugan Hewei Decoction Alleviates Cecum Mucosal Injury and Improves Depressive- and Anxiety-Like Behaviors in Chronic Stress Model Rats by Regulating Cecal Microbiota and Inhibiting NLRP3 Inflammasome

Chronic stress is a significant cause of depression, anxiety, and intestinal mucosal injury. Gut microbiota disturbances are also associated with these disorders. Shugan Hewei Decoction (SHD), which is a traditional Chinese medicine formula developed by our team, has shown superior therapeutic effects in the treatment of depression, anxiety, and functional gastrointestinal diseases caused by chronic stress. In this study, we investigated the modulatory effect of SHD on the cecal microbiota and cecum mucosal NOD-like receptor protein 3 (NLRP3) inflammasome in a chronic unpredictable stress (CUS)/social isolation rat model. After the SHD intervention, the CUS model rats showed improvements in their depressive- and anxiety-like behaviors, as well as sustained body weight growth and improved fecal characteristics. SHD improved the cecal microbiota diversity and changed the abundance of six microbial genera. A Spearman's correlation analysis showed a strong correlation between the NLRP3 inflammasome and CUS-perturbed cecal biomarker microbiota. SHD regulated the excessive expression of NLRP3, ASC, caspase-1, interleukin-1β (IL-1β), and IL-18 in the serum and cecum mucosa induced by CUS, as well as the activation of the Toll-like receptor 4/nuclear factor-κB signaling cascades. Our results reveal the pharmacological mechanisms of SHD and provide a validated therapeutic method for the treatment of depression, anxiety, and cecum mucosal injury.

Oral coniferyl ferulate attenuated depression symptoms in mice via reshaping gut microbiota and microbial metabolism

The gut microbiome is known to be involved in depression development. Thus, phytochemicals changing gut microbiota may alleviate depression-like behaviors. Coniferyl ferulate (CF) is a long studied natural product and known to alleviate psychiatric disorders. However, its mechanism of action remains unclear. In this experimental study, oral administration of 50 mg kg^-1 CF once daily attenuated weight loss and depression-like and anxiety-like behaviors induced by chronic unpredicted mild stress (CUMS) in mice. Four weeks of CF administration significantly ameliorated colonic inflammation, lowered the levels of IL-6, IL-1β, and TNF-α, and restructured the gut microbiome, and microbial metabolism. Intestinal microbiota can impact the development and function of the brain via the microbiota-gut-brain axis. Therefore, oral administration of CF is a promising nutritional strategy to treat CUMS-induced depression via the regulation of microbiota and microbial metabolism.

Multi-omics data reveals the disturbance of glycerophospholipid metabolism caused by disordered gut microbiota in depressed mice

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Three important ”metabolite type-bacterial genus” correlated pairs were identified.

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Peripheral and central GP metabolism was disordered in depressed mice.

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Four differential NEs from tryptophan pathway in hippocampus were found.

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“Firmicutes-SCFAs-GP metabolism-Tryptophan pathway” was possible way in gut-brain.

Introduction

Although researchers have done intensive research on depression, its pathogenesis is still not fully explained. More and more evidence suggests that gut microbiota is closely related to the onset of depression; but its specific functional ways are not clearly identified.

Objectives

The purpose of our work was to find out how the gut microbiota was involved in the onset of depression, and to identify the potential ways to link the gut and brain in mice with depressive-like behaviors (DLB).

Methods

We used the chronic restraint stress (CRS)-induced depression model here. Gut microbiota compositions in fecal samples, lipid metabolism (in fecal, serum and hippocampus samples) and neurotransmitters in hippocampus samples were detected.

Results

We found that the 7 of 13 differential genera that significantly correlated with DLB belonged to phylum Firmicutes. The differential lipid metabolites in fecal samples mainly belonged to glycerophospholipids (GP) and fatty acids (FA) metabolism, and three important “metabolite type-bacterial taxa” correlated pairs were identified: “FA/GP-Firmicutes”, “FA/GP-Akkermansia”, and “FA/GP-Bifidobacterium”. The key differential lipid metabolites significantly correlated with DLB mainly belonged to FA and GP, and the DLB-related metagenomic genes were consistently enriched in GP metabolism and FA metabolism. Three significantly changed short-chain fatty acids (SCFAs) were significantly correlated with the majority of differential genera. Meanwhile, we found that the differential lipid metabolites in serum and hippocampus samples were mainly mapped into the GP metabolism, and there were four differential neurotransmitters from the tryptophan pathway in hippocampus samples.

Conclusion

Together, our findings could provide novel insights into the role of “microbiota-gut-brain” (MGB) axis in depression, and indicate that the gut microbiota might have a vital role in the onset of DLB by affecting the peripheral/central GP metabolism and tryptophan pathway. The “Firmicutes-SCFAs-GP metabolism-Tryptophan pathway” might be a possible way to link the gut and brain in depressed mice.