Gypenosides reverses depressive behavior via inhibiting hippocampal neuroinflammation

Chronic Stress-Induced Neuroinflammation: Relevance of Rodent Models to Human Disease

The brain is the central organ of adaptation to stress because it perceives and determines threats that induce behavioral, physiological, and molecular responses. In humans, chronic stress manifests as an enduring consistent feeling of pressure and being overwhelmed for an extended duration. This can result in a persistent proinflammatory response in the peripheral and central nervous system (CNS), resulting in cellular, physiological, and behavioral effects. Compounding stressors may increase the risk of chronic-stress-induced inflammation, which can yield serious health consequences, including mental health disorders. This review summarizes the current knowledge surrounding the neuroinflammatory response in rodent models of chronic stress-a relationship that is continually being defined. Many studies investigating the effects of chronic stress on neuroinflammation in rodent models have identified significant changes in inflammatory modulators, including nuclear factor-κB (NF-κB) and toll-like receptors (TLRs), and cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6. This suggests that these are key inflammatory factors in the chronic stress response, which may contribute to the establishment of anxiety and depression-like symptoms. The behavioral and neurological effects of modulating inflammatory factors through gene knockdown (KD) and knockout (KO), and conventional and alternative medicine approaches, are discussed.

The potential molecular mechanism underlying gypenoside amelioration of atherosclerosis in ApoE-/- mice: A multi-omics investigation

Gypenosides (Gyp) are bioactive components of Gynostemma pentaphyllum that have a variety of pharmacological properties. Extracts of G. pentaphyllum have been found to be effective in the reduction of blood sugar and lipids and prevention of atherosclerosis. Here, the functions of Gyp and the mechanisms underlying their effects on atherosclerosis were investigated. Mice were allocated to three groups, namely, the control (C57BL/6), atherosclerosis model (ApoE-/- mice with high-fat diet), and Gyp-treated groups. Differentially expressed mRNAs, miRNAs, circRNA, and differential metabolites among the groups were analyzed. The results showed that "Fatty acid metabolism", "Fatty acid elongation", "Cytokine-cytokine receptor interaction", and "PI3K-Akt signaling pathway", amongst others, were involved in treatment process. Differentially expressed genes, including Fabp1, Apoe, FADS1, ADH1, SYNPO2, and Lmod1were also identified. Mmu-miR-30a and mmu-miR-30e showed reduced expression in atherosclerosis models but were increased following Gyp treatment, suggesting involvement in the effects of Gyp. In addition, chr5:150604177-150608440 were found to interact with mmu-miR-30a and mmu-miR-30e to regulate their abundance. In terms of metabolomics, Gyp may regulate biological processes involving PGD2 and PGJ2, potentially alleviating atherosclerosis. In conclusion, Gyp appeared to have complex effects on atherosclerosis, most of which were positive. These results support the use of Gyp in the treatment of atherosclerosis.

Gypenoside XLIX alleviates acute liver injury: Emphasis on NF-κB/PPAR-α/NLRP3 pathways

Liver is one of the vital organs in the human body and liver injury will have a very serious impact on human damage. Gypenoside XLIX is a PPAR-α activator that inhibits the activation of the NF-κB signaling pathway. The components of XLIX have pharmacological effects such as cardiovascular protection, antihypoxia, anti-tumor and anti-aging. In this study, we used cecum ligation and puncture (CLP) was used to induce in vivo mice hepatic injury, and lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells, evaluated whether Gypenoside XLIX could have a palliative effect on sepsis-induced acute liver injury via NF-κB/PPAR-α/NLRP3. In order to gain insight into these mechanisms, six groups were created in vivo: the Contol group, the Sham group, the CLP group, the CLP + XLIX group (40 mg/kg) and the Sham + XLIX (40 mg/kg) group, and the CLP + DEX (2 mg/kg) group. Three groups were created in vitro: Control, LPS, LPS + XLIX (40 μM). The analytical methods used included H&E staining, qPCR, reactive oxygen species (ROS), oil red O staining, and Western Blot. The results showed that XLIX attenuated hepatic inflammatory injury in mice with toxic liver disease through inhibition of the TLR4-mediated NF-κB pathway, attenuated lipid accumulation through activation of PPAR-α, and attenuated hepatic pyroptosis by inhibiting NLRP3 production. Regarding the imbalance between oxidative and antioxidant defenses due to septic liver injury, XLIX reduced liver oxidative stress-related biomarkers (ALT, AST), reduced ROS accumulation, decreased the amount of malondialdehyde (MDA) produced by lipid peroxidation, and increased the levels of antioxidant enzymes such as glutathione (GSH) and catalase (CAT). Our results demonstrate that XLIX can indeed attenuate septic liver injury. This is extremely important for future studies on XLIX and sepsis, and provides a potential pathway for the treatment of acute liver injury.

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.

Microgliosis: a double-edged sword in the control of food intake

Maintaining energy balance is essential for survival and health. This physiological function is controlled by the brain, which adapts food intake to energy needs. Indeed, the brain constantly receives a multitude of biological signals that are derived from digested foods or that originate from the gastrointestinal tract, energy stores (liver and adipose tissues) and other metabolically active organs (muscles). These signals, which include circulating nutrients, hormones and neuronal inputs from the periphery, collectively provide information on the overall energy status of the body. In the brain, several neuronal populations can specifically detect these signals. Nutrient-sensing neurons are found in discrete brain areas and are highly enriched in the hypothalamus. In turn, specialized brain circuits coordinate homeostatic responses acting mainly on appetite, peripheral metabolism, activity and arousal. Accumulating evidence shows that hypothalamic microglial cells located at the vicinity of these circuits can influence the brain control of energy balance. However, microglial cells could have opposite effects on energy balance, that is homeostatic or detrimental, and the conditions for this shift are not totally understood yet. One hypothesis relies on the extent of microglial activation, and nutritional lipids can considerably change it.

Role of BDNF-TrkB signaling in the antidepressant-like actions of loganin, the main active compound of Corni Fructus

AIMS

Corni Fructus (CF) and some CF-contained prescriptions are commonly used in clinical treatment of depression. This investigation aims to evaluate the main active compound of CF in antidepressant properties and its key target.

METHODS

Firstly, this study established a behavioral despair model and used high-performance liquid chromatography method to evaluate the antidepressant-like effects of water extract, 20%, 50%, and 80% ethanol extracts of CF, and its main active compound. Then, this study created chronic unpredictable mild stress (CUMS) model to assess loganin's antidepressant-like properties, and its target was evaluated by quantitative real-time polymerase chain reaction, Western blot, Immunofluorescence, enzyme-linked immunosorbent assay, and tyrosine receptor kinase B (TrkB) inhibitor.

RESULTS

Results showed that the different extracts of CF significantly shortened the immobility time in forced swimming and tail suspension tests. Moreover, loganin alleviated CUMS-induced depression-like behavior, promoted neurotrophy and neurogenesis, and inhibited neuroinflammation. Furthermore, K252a blocked the improvement of loganin on depression-like behavior, and eliminated the enhancement of neurotrophy and neurogenesis and the inhibition of neuroinflammation.

CONCLUSION

Overall, these results indicated that loganin could be used as a major active compound of CF for the antidepressant-like properties and exerted antidepressant-like actions by regulating brain derived neurotrophic factor (BDNF)-TrkB signaling, and TrkB could be used as key target for itsantidepressant-like actions.

Gypenoside-14 Reduces Depression via Downregulation of the Nuclear Factor Kappa B (NF-kB) Signaling Pathway on the Lipopolysaccharide (LPS)-Induced Depression Model

Neuroinflammation is a common pathogenetic sign of depression and is closely linked to the development of depression. Many clinical anti-inflammatory drugs act as antidepressants by reducing the neuroinflammatory response. Previous research found that gypenosides and their bioactive compound gypenoside-14 (GP-14) had neuroprotective effects against hypoxia-induced injury and reduced neuroinflammation-related high-altitude cerebral edema. Here we investigated the effects of GP-14 on the lipopolysaccharide (LPS)-induced depression-like behavior model. LPS (0.5 mg/kg) was injected into mice intraperitoneally for 7 consecutive days to induce depression-like behavior, which is considered a model for the exacerbation of depression. GP-14 in the amount of 100 mg/kg was simultaneously administered by gavage for 7 days. In the LPS-induced depression model, GP-14 not only attenuated depression-like behavior but also improved the anxiety-like behavior of the mice. Additionally, GP-14 treatment mitigated learning and cognitive decline in depressed mice. ELISA and immunofluorescence staining results revealed that GP-14 inhibited the upregulation of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and suppressed the activation of astrocytes induced with LPS, indicating its potent anti-inflammatory effect. GP-14 pretreatment in C8 cells and primary astrocytes can inhibit the activation of the NF-κB signaling pathway and downregulate the levels of pro-inflammatory factors. In summary, our findings showed that GP-14 had significant anti-inflammation and anti-depression properties; thus, GP-14 could be a promising lead compound for treating depression.

Gypenosides suppress fibrosis of the renal NRK-49F cells by targeting miR-378a-5p through the PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of renal fibrosis caused by chronic kidney disease is increasing year by year. Preventing the activation and conversion of kidney-intrinsic fibroblasts to a myofibroblast phenotype is an important target for blocking the development of renal interstitial fibrosis. Our team established a stable renal interstitial fibrosis cell model in the early stage, and the screening results showed that GPs has good anti-fibrosis potential. At this stage, only a few literatures have reported its anti-fibrosis effect, and the mechanism of action is still unclear.

AIM OF THE STUDY

The massive synthesis and secretion of extracellular-matrix (ECM) components by activated fibroblasts in the kidneys causes irreversible renal interstitial fibrosis. Gypenosides (GPs) have been shown to decelerate this process, in which micro RNAs (miRNAs) play an important regulatory role. This study aimed to evaluate the mechanism underlying the suppressive effect of GPs on renal fibrosis.

MATERIALS AND METHODS

This study used TGF-β1-stimulated NRK-49F renal cells as an in-vitro model of renal interstitial fibrosis. First, the concentration range of GPs that significantly affects the cytoactive was determined. Then, the anti-fibrotic effects of various concentrations of GPs in the in-vitro model were assessed via immunofluorescence, western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Non-coding-RNA sequencing combined with bioinformatics was used to predict the mechanistic basis of the anti-fibrotic effect of GPs, and qRT-PCR was used to verify the sequencing results and bioinformatic predictions. The identified relationships of the anti-fibrotic effect of GPs with miR-378a-5p and the PI3K/AKT signaling were evaluated using a miR-NC mimic and the PI3K inhibitor LY294002 as controls, respectively.

RESULTS

TGF-β1 stimulation up-regulated α-SMA, COL1, and COL3 in NRK-49F cells, and this effect was suppressed by GPs. Additionally, TGF-β1 stimulation significantly changed the expression levels of 151 miRNAs, and GPs significantly suppressed the effect of TGF-β1 on the levels of 18 of these miRNAs. Among them, miR-3588 and miR-378a-5p were down-regulated, and miR-135b-5p and miR-3068-5p were up-regulated upon TGF-β1 induction. Of these miRNAs, miR-378a-5p was predicted to target the mRNAs of numerous proteins mainly enriched in the PI3K/AKT signaling pathway. The miRNA transfection experiments with the miR-NC mimic and PI3K inhibitor as controls showed that miR-378a-5p overexpression could suppress the TGF-β1-induced up-regulation of α-SMA, COL1, PI3K, and AKT, including the phosphorylated form (p-AKT).

CONCLUSION

GPs inhibit the PI3K/AKT signaling by up-regulating miR-378a-5p in TGF-β1-stimulated NRK-49F cells and thereby reduce their massive secretion of ECM components. Given that this in-vitro model of renal interstitial fibrosis closely mimics the in-vivo pathogenesis, our results most likely apply to the in-vivo conditions.

Inflammatory Immune Process and Depression-like Behavior in Hypothyroid Rats: A [18F] DPA-714 Micro Positron Emission Tomography Study

Hypothyroidism is closely related to mental disorders, mainly depression, through an as-yet-unknown mechanism. The cerebral inflammatory immune process has been implied to play a pivotal role in the onset of affective symptoms in several conditions. In order to gain insight into the mechanism underlying the depressive behaviors in hypothyroid rats, brain microglial activation was evaluated using micro positron emission tomography imaging with a translocator protein (TSPO) radioligand. Hypothyroidism was induced in adult male Wistar rats by administration of 0.05% propylthiouracil in drinking water for five weeks. Open field, forced swimming and tail suspension tests were employed to evaluate the depressive behavior in hypothyroid rats, and the relationship between the behavioral changes and brain microglial activation was evaluated using [18F] DPA-714 micro positron emission tomography imaging. The open field test revealed significantly reduced first-minute activity and rearing behavior in the hypothyroid group, as well as significantly increased immobility in the forced swimming test and the tail suspension test. Hypothyroidism induced significantly increased microglial activation in the hippocampus. The radioligand uptake in the hippocampus correlated negatively with first-minute activity in the open field test (p < 0.05), and the radioligand uptake in the hippocampus correlated positively with changes in the immobility time in the forced swimming test and the tail suspension test (p < 0.05). Immunohistochemistry also confirmed the activation of microglia and inflammatory bodies in hypothyroid rats. The results indicate that hypothyroidism can induce depressive behavior in adult Wistar rats, microglial activation in the hippocampus plays an important role in the depressive behavior in hypothyroid rats and the inflammatory immune mechanism may underlie the behavioral abnormalities in thyroid dysfunction. Furthermore, the findings in the present study suggest there might be a common mechanism underlying depressive behavior in adult-onset hypothyroidism and depression.

Agomelatine Changed the Expression and Methylation Status of Inflammatory Genes in Blood and Brain Structures of Male Wistar Rats after Chronic Mild Stress Procedure

The preclinical research conducted so far suggest that depression development may be influenced by the inflammatory pathways both at the periphery and within the central nervous system. Furthermore, inflammation is considered to be strongly connected with antidepressant treatment resistance. Thus, this study explores whether the chronic mild stress (CMS) procedure and agomelatine treatment induce changes in TGFA, TGFB, IRF1, PTGS2 and IKBKB expression and methylation status in peripheral blood mononuclear cells (PBMCs) and in the brain structures of rats. Adult male Wistar rats were subjected to the CMS and further divided into matched subgroups to receive vehicle or agomelatine. TaqMan gene expression assay and methylation-sensitive high-resolution melting (MS-HRM) were used to evaluate the expression of the genes and the methylation status of their promoters, respectively. Our findings confirm that both CMS and antidepressant agomelatine treatment influenced the expression level and methylation status of the promoter region of investigated genes in PBMCs and the brain. What is more, the present study showed that response to either stress stimuli or agomelatine differed between brain structures. Concluding, our results indicate that TGFA, TGFB, PTGS2, IRF1 and IKBKB could be associated with depression and its treatment.

Gypenoside XVII, an Active Ingredient from Gynostemma Pentaphyllum, Inhibits C3aR-Associated Synaptic Pruning in Stressed Mice

Gynostemma pentaphyllum is a herbal medicine widely used in Asian countries, and its saponin extracts have been shown to possess potent anti-inflammatory effects. Gypenoside XVII, an active ingredient isolated from Gynostemma pentaphyllum, has been found to alleviate the inflammation induced by LPS in the BV2 microglia, according to our preliminary study. This study aims to evaluate whether Gypenoside XVII could attenuate depression-like symptoms in vivo and tries to demonstrate the involvement of the complement regulation in its antidepressant-like effect. The results showed that Gypenoside XVII significantly attenuated depression-like behaviors in the forced swimming test, tail suspension test and sucrose preference test. It also alleviated the acute stress-induced hyperactivity of serum corticosterone levels. Additionally, Gypenoside XVII significantly inhibited the activation of microglia and the expression of C3 in mice exposed to chronic unpredictable mild stress (CUMS). Meanwhile, the activation of C3aR/STAT3 signaling and the expression of proinflammatory cytokines was reversed by Gypenoside XVII. Moreover, CUMS induced excessive synaptic pruning by activating microglia, while Gypenoside XVII restored it in the prefrontal cortex. Our data demonstrated that Gypenoside XVII, the active ingredient of Gynostemma pentaphyllum, produced the antidepressant-like effects in mice, which was mediated by the inhibition of complement C3/C3aR/STAT3/cytokine signaling in the prefrontal cortex.

Microglia in depression: an overview of microglia in the pathogenesis and treatment of depression

Major depressive disorder is a highly debilitating psychiatric disorder involving the dysfunction of different cell types in the brain. Microglia are the predominant resident immune cells in the brain and exhibit a critical role in depression. Recent studies have suggested that depression can be regarded as a microglial disease. Microglia regulate inflammation, synaptic plasticity, and the formation of neural networks, all of which affect depression. In this review, we highlighted the role of microglia in the pathology of depression. First, we described microglial activation in animal models and clinically depressed patients. Second, we emphasized the possible mechanisms by which microglia recognize depression-associated stress and regulate conditions. Third, we described how antidepressants (clinical medicines and natural products) affect microglial activation. Thus, this review aimed to objectively analyze the role of microglia in depression and focus on potential antidepressants. These data suggested that regulation of microglial actions might be a novel therapeutic strategy to counteract the adverse effects of devastating mental disorders.

GP-14 protects against severe hypoxia-induced neuronal injury through the AKT and ERK pathways and its induced transcriptome profiling alteration

Gypenosides are major bioactive ingredients of G. pentaphyllum. In our previous study, we found that gypenosides had neuroprotective effects against hypoxia-induced injury. In the current study, we focused on the protective effects of gypenoside-14 (GP-14), which is one of the newly identified bioactive components, on neuronal injury caused by severe hypoxia (0.3% O₂). The results showed that GP-14 pretreatment alleviated the cell viability damage and apoptosis induced by hypoxia in PC12 cells. Moreover, GP-14 pretreatment also attenuated primary neuron injuries under hypoxic conditions. Additionally, GP-14 pretreatment significantly ameliorated neuronal damage in the hippocampal region induced by high-altitude cerebral edema (HACE). At the molecular level, GP-14 pretreatment reversed the decreased activities of the AKT and ERK signaling pathways caused by hypoxia in PC12 cells and primary neurons. To comprehensively explore the possible mechanisms, transcriptome sequencing was conducted, and these results indicated that GP-14 could alter the transcriptional profiles of primary neuron. Taken together, our results suggest that GP-14 acts as a neuroprotective agent to protect against neuronal damage induced by severe hypoxia and it is a promising compound for the development of neuroprotective drugs.

Mechanistic Studies of Gypenosides in Microglial State Transition and its Implications in Depression-Like Behaviors: Role of TLR4/MyD88/NF-κB Signaling

Depression is a prevalent psychiatric disorder. Microglial state transition has been found in many neurological disorders including depression. Gypenosides (Gypenosides I-LXXVIII, Gps) are saponin extracts isolated from the traditional Chinese herb Gynostemma pentaphyllum (Thunb.) Makino that exert anti-inflammatory and neuroprotective activities and regulate depression-like behaviors. However, its effect on microglial state transition in depression remains unknown. We aimed to evaluate the potential relationship between Gps and TLR4/MyD88/NF-κB signaling in microglial state transition in vitro and in vivo. First, BV-2 cells (microglial cell line) were exposed to lipopolysaccharides (LPS) and treated with 10 or 5 μg/ml Gps. Second, the chronic unpredictable mild stress (CUMS)-induced depression mouse model was used to investigate the antidepressant-like behaviors effects of Gps (100 or 50 mg/kg). We determined depression-like behaviors using the open-field test (OFT), forced swim test (FST), and sucrose preference test (SPT). Proteins and inflammatory factors in the TLR4/MyD88/NF-κB signaling pathway and the different microglial reaction states markers were subsequently conducted using enzyme-linked immunosorbent assay, immunocytochemistry, immunofluorescence, qPCR, or Western blotting analyses to evaluate the anti-inflammatory and antidepressant properties of Gps and the underlying molecular mechanisms. We found that Gps regulated the microglial cell line state transition in LPS-exposed BV-2 cells, as evidenced by the significantly decreased expression of inflammatory parameters iNOS, IL-1β, IL-6, and TNF-α and significantly promoted anti-inflammatory microglial phenotypes markers CD206 (Mrc1) and IL-10. More importantly, Gps protected against the loss of monoamine neurotransmitters and depression-like behavior in a mouse model of depression, which was accompanied by a regulation of the microglial state transition. Mechanistically, Gps inhibited TLR4/MyD88/NF-κB signaling, which reduced the release of downstream inflammatory cytokines (IL-1β, IL-6, and TNF-α) and promoted microglial phenotype transition, which all together contributed to the antidepressant effect. Our results suggest that Gps prevents depression-like behaviors by regulating the microglial state transition and inhibiting the TLR4/MyD88/NF-κB signaling pathway. Thus, Gps could be a promising therapeutic strategy to prevent and treat depression-like behaviors and other psychiatric disorders.

A bioactive gypenoside (GP-14) alleviates neuroinflammation and blood brain barrier (BBB) disruption by inhibiting the NF-κB signaling pathway in a mouse high-altitude cerebral edema (HACE) model

BACKGROUND

Neuroinflammation caused by peripheral lipopolysaccharides (LPS) under hypoxia is a key contributor to the development of high altitude cerebral edema (HACE). Our previous studies have shown that gypenosides and their bioactive compounds prevent hypoxia-induced neural injuries in vitro and in vivo. However, their effect on neuroinflammation-related HACE remains to be illustrated. The present study aimed to investigate the effects of GP-14 in HACE mouse model.

METHODS

HACE mice were treated with GP-14 (100 and 200 mg/kg) for 7 days. After the treatments, the level of serum inflammation cytokines and the transcription of inflammatory factors in brain tissue were determined. The activation of microglia, astrocyte and the changes of IgG leakage and the protein levels of tight junction proteins were detected. Furthermore, the inflammatory factors and nuclear factor-κB (NF-κB) signaling pathway in BV-2 cells and primary microglia were detected.

RESULTS

GP-14 pretreatment alleviated both the serum and neural inflammatory responses caused by LPS stimulation combined with hypobaric hypoxia exposure. In addition, GP-14 pretreatment inhibited microglial activation, accompanied by a decrease in the M1 phenotype and an increase in the M2 phenotype. Moreover, the disruption of the blood brain barrier (BBB) integrity, including increased IgG leakage and decreased expression of tight junction proteins, was attenuated by GP-14 pretreatment. Based on the BV-2 and primary microglial models, the inflammatory response and activation of the NF-κB signaling pathway were also inhibited by GP-14 pretreatment.

CONCLUSION

Taken together, our results demonstrated that GP-14 exhibited prominent protective roles against neuroinflammation and BBB disruption in a mouse HACE model. GP-14 could be a potential choice for the treatment of HACE in the future.

Acupuncture Ameliorates Depressive Behaviors by Modulating the Expression of Hippocampal Iba-1 and HMGB1 in Rats Exposed to Chronic Restraint Stress

The antidepressant mechanism of acupuncture has not been fully elucidated recently. Thus, the objective of the present study is to investigate the antidepressant mechanism of acupuncture of modulating the neuroinflammation induced by high mobility group box-1 (HMGB1) in rats subjected to chronic restraint stress (CRS). Forty-four male Sprague Dawley rats were randomly divided into control, model, escitalopram, and acupuncture group. Except for rats in the control group, all rats were exposed to CRS for 21 days continuously. Rats in the escitalopram group were subjected to a suspension of escitalopram and saline. One hour before CRS procedures, acupuncture was performed at Baihui (GV20) and Yintang (GV29) for rats in the acupuncture group, 20 min per day for 21 days. All rats in each group were conducted to detect the body weight, sucrose preference test at 0, 7, 14, 21 days to evaluate the depression-like behaviors. The expression of microglial activation and HMGB1 in the hippocampus was detected by immunofluorescence. The expression of hippocampal interleukin-10 (IL-10) was detected by western blot. And the content of serum tumor necrosis factor-α (TNF-α) was detected by the enzyme-linked immunosorbent assay method. CRS-exposed rats showed obviously decreased body weight and sucrose preference when compared with the control group, which was reversed by acupuncture. The results have also shown that acupuncture ameliorated the CRS-induced activation of microglia and HMGB1 in the hippocampus CA1 region. Furthermore, acupuncture reduced the stress-induced upregulation of TNF-α in serum. Collectively, the current study highlights the role of acupuncture in alleviating depressive behavior associated with stress-induced neuroinflammation mediated by HMGB1 in the CRS model of depression.

Uncovering the anti-NSCLC effects and mechanisms of gypenosides by metabolomics and network pharmacology analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Lung cancer is the chief reason of cancer death worldwide, and non-small cell lung cancer (NSCLC) make up the majority of lung cancers. Gypenosides are the main active constituents from Gynostemma pentaphyllum. Previous studies showed that they were used to remedy many cancers. The effect of gypenosides on NSCLC has never been studied from the perspective of network pharmacology and metabolomics. The mechanism is still not clear and remains to be explored.

AIM OF THE STUDY

To explore the anti-NSCLC activity and mechanism of gypenosides in A549 cells.

MATERIAL/METHODS

Gypenosides of G. pentaphyllum were detected by HPLC-MS. The cytotoxicity was detected by MTT assay. The migration, cell cycle and apoptosis of gypenosides were studied by wound healing assay, JC-1 assay and flow cytometry. The mechanism of gypenosides on NSCLC was studied by metabolomics and network pharmacology. Some key proteins and pathways were further confirmed by Western blot.

RESULTS

Eleven gypenosides were detected by HPLC-MS. Gypenosides could suppress the proliferation of A549 cells, inhibit the migration of A549 cells, induce apoptosis and arrest cell cycle in G0/G1 phase. Metabolomics and network pharmacology approach revealed that gypenosides might affect 17 metabolite related proteins by acting on 9 candidate targets (STAT3, VEGFA, EGFR, MMP9, IL2, TYMS, FGF2, HPSE, LGALS3), thus resulting in the changes of two metabolites (uridine 5'-monophosphate, D-4'-Phosphopantothenate) and two metabolic pathways (pyrimidine metabolism; pantothenate and CoA biosynthesis). Western blotting indicated that gypenosides might inhibit A549 cells through MMP9, STAT3 and TYMS to indirectly affect the pathways of pyrimidine metabolism, pantothenate and CoA biosynthesis.

CONCLUSIONS

This study revealed that metabolomics combined with network pharmacology was conducive to understand the anti-NSCLC mechanism of gypenosides.

Unraveling the metabolic pathway of choline-TMA-TMAO: Effects of gypenosides and implications for the therapy of TMAO related diseases

Trimethylamine-N-oxide (TMAO) has emerged as a promising new therapeutic target for the treatment of central nervous system diseases, atherosclerosis and other diseases. However, its origin in the brain is unclear. Gynostemma pentaphyllum (Thunb.) Makino can reduce the increase of TMAO level caused by a high fat diet. But its effective chemical composition and specific mechanism have not been reported. The study confirmed that TMA was more easily to penetrate blood brain barrier than TMAO, the MAO enzyme was partly involved in the transformation of the TMA in brain, which further supplemented the choline-TMA-TMAO pathway. Based on the above metabolic pathway, using multi-omics approaches, such as microbiodiversity, metagenomics and lipidomics, it was demonstrated that the reduction of plasma TMAO levels by gypenosides did not act on FMO3 and MAO in the pathway, but remodeled the microbiota and affected the trimethylamine lyase needed in the conversion of choline to TMA in intestinal flora. At the same time, gypenosides interfered with enzymes associated with TCA and lipid metabolism, thus affecting TMAO and lipid metabolism. Considering the bidirectional transformation of phosphatidycholine and choline, lipid metabolism and TMAO metabolism could affected each other to some extent. In conclusion, our study revealed the intrinsic correlation between long-term application of gypenosides to lipid reduction and nervous system protection, and explained why gypenosides were used to treat brain diseases, even though they had a poor ability to enter the brain. Besides, it provided a theoretical basis for clinical application of gypenosides and the development of new drugs.

Antidepressant effect of catalpol on corticosterone-induced depressive-like behavior involves the inhibition of HPA axis hyperactivity, central inflammation and oxidative damage probably via dual regulation of NF-κB and Nrf2

This study aimed to investigate the antidepressant effect and mechanism of catalpol on corticosterone (CORT)-induced depressive-like behavior in mice for the first time. As a result, CORT injection induced depressive-like behaviors of mice in behavioral tests, aggravated the serum CORT, adrenocorticotropic hormone, and corticotropin-releasing hormone levels, and conspicuously elevated the phosphorylations of nuclear factor kappa-B (NF-κB) in the hippocampus and frontal cortex, and down-regulated the expression levels of nuclear factor erythroid-2-related factor 2 (Nrf2). Furthermore, CORT exposure dramatically augmented the levels of inflammatory factors (interleukin-1β, tumor necrosis factor-α, nitric oxide synthase, and nitric oxide) and lipid peroxidation product malondialdehyde, and attenuated the levels of antioxidants including reduced glutathione, glutathione S-transferase, total superoxide dismutase, and heme oxygenase-1 in the mouse hippocampus and frontal cortex. On the contrary, catalpol administration markedly suppressed the abnormalities of the above indicators. From the overall results, this study displayed that catalpol exerted a beneficial effect on CORT-induced depressive-like behavior in mice possibly via the inhibition of hypothalamus-pituitary-adrenal (HPA) axis hyperactivity, central inflammation and oxidative damage at least partially through dual regulation of NF-κB and Nrf2.

Beneficial effects of running exercise on hippocampal microglia and neuroinflammation in chronic unpredictable stress-induced depression model rats

Running exercise has been shown to relieve symptoms of depression, but the mechanisms underlying the antidepressant effects are unclear. Microglia and concomitant dysregulated neuroinflammation play a pivotal role in the pathogenesis of depression. However, the effects of running exercise on hippocampal neuroinflammation and the number and activation of microglia in depression have not been studied. In this study, rats were subjected to chronic unpredictable stress (CUS) for 5 weeks followed by treadmill running for 6 weeks. The depressive-like symptoms of the rats were assessed with a sucrose preference test (SPT). Immunohistochemistry and stereology were performed to quantify the total number of ionized calcium-binding adapter molecule 1 (Iba1)⁺ microglia, and immunofluorescence was used to quantify the density of Iba1⁺/cluster of differentiation 68 (CD68)⁺ in subregions of the hippocampus. The levels of proinflammatory cytokines in the hippocampus were measured by qRT-PCR and ELISA. The results showed that running exercise reversed the decreased sucrose preference of rats with CUS-induced depression. In addition, CUS increased the number of hippocampal microglia and microglial activation in rats, but running exercise attenuated the CUS-induced increases in the number of microglia in the hippocampus and microglial activation in the dentate gyrus (DG) of the hippocampus. Furthermore, CUS significantly increased the hippocampal levels of inflammatory factors, and the increases in inflammatory factors in the hippocampus were suppressed by running exercise. These results suggest that the antidepressant effects of exercise may be mediated by reducing the number of microglia and inhibiting microglial activation and neuroinflammation in the hippocampus.

Role and characteristics of hippocampal region microglial activation in poststroke depression

AIMS

To study the role and characteristics of activated microglia in poststroke depression (PSD) .

METHODS

Twenty-four male Wistar rats were randomly divided into three groups: the poststroke (PS) group, PSD group, and Sham group. Neurobehavioral testing was performed 24 h postoperation. The body weights of the rats were regularly recorded, and behavioral testing was regularly performed at 1, 2 and 3 weeks postmodeling. Immunofluorescent staining was used to detect the microglial marker OX42. Real-time PCR was used to analyze the relative gene expression of microglial activation markers (TNF-a, IL-10, IL-1, TGF-β, CD86, iNOS, CD206, IL-1β, and Arg1) .

RESULTS

The relative gene expression of proinflammatory markers (IL-1, TNF-a, iNOS, and IL1β) and anti-inflammatory markers (CD206 and Arg1) significantly increased in the hippocampal region compared with that in the right cerebral and left cerebral hemispheres in the PSD group. The relative gene expression of proinflammatory markers (TNF-a, IL-1, iNOS, and CD86) in the hippocampal region was significantly increased in the PSD group compared with that in the Sham and PS groups. The anti-inflammatory markers (TGF-β and CD206) in the hippocampal region were significantly increased in the PSD group compared with that in the Sham group, and the M2 marker Arg1 was significantly increased in the PSD group compared with that in the PS group. Correlation analysis showed that IL-1 was strongly negatively correlated with PSD .

CONCLUSIONS

Most microglia in the hippocampal region of PSD had a proinflammatory status and an anti-inflammatory status. IL-1 showed a strong negative correlation with PSD.

Chronic Mild Stress and Venlafaxine Treatment Were Associated with Altered Expression Level and Methylation Status of New Candidate Inflammatory Genes in PBMCs and Brain Structures of Wistar Rats

Preclinical studies conducted to date suggest that depression could be elicited by the elevated expression of proinflammatory molecules: these play a key role in the mediation of neurochemical, neuroendocrine and behavioral changes. Thus, this study investigates the effect of chronic mild stress (CMS) and administration of venlafaxine (SSRI) on the expression and methylation status of new target inflammatory genes: TGFA, TGFB, IRF1, PTGS2 and IKBKB, in peripheral blood mononuclear cells (PMBCs) and in selected brain structures of rats. Adult male Wistar rats were subjected to the CMS and further divided into matched subgroups to receive vehicle or venlafaxine. TaqMan gene expression assay and methylation-sensitive high-resolution melting (MS-HRM) were used to evaluate the expression of the genes and the methylation status of their promoters, respectively. Our results indicate that both CMS and chronic treatment with venlafaxine were associated with changes in expression of the studied genes and their promoter methylation status in PMBCs and the brain. Moreover, the effect of antidepressant administration clearly differed between brain structures. Summarizing, our results confirm at least a partial association between TGFA, TGFB, IRF1, PTGS2 and IKBKB and depressive disorders.

Antidepressant-like Effects of Degraded Porphyran Isolated from Porphyra haitanensis

INTRODUCTION

Degraded porphyran is a bioactive polysaccharide extracted from Porphyra haitanensis (P. haitanensis). According to the previous studies, it produced anti-inflammatory activity, but little is known about its effects on depression.

METHODS AND RESULTS

As inflammation is one of the critical factors involved in the development of depression, this study aims to elucidate the potential antidepressant-like effects of degraded porphyran. The results show that acute porphyran treatment decreased the immobility time in despair tests. In addition, subchronic porphyran administration reverses depressive-like behaviors in lipopolysaccharide (LPS)-treated mice. Meanwhile, porphyran inhibits NF-κB/NLRP3 signaling, proinflammatory cytokine release, and microglial activation in the hippocampus. Moreover, chronic porphyran treatment activates hippocampal brain derived neurotrophic factor (BDNF)/TrkB/ERK/CREB signaling pathway in chronic unpredictable mild stress (CUMS) in mice. As a result, neurogenesis and spinogenesis are maintained.

CONCLUSIONS

The findings of the present study indicate that degraded porphyran intake provides a potential strategy for depression treatment, which is mediated by the inhibition of neuroinflammation and the enhancement of neurogenesis and spinogenesis in the central nervous systems.

Gypenosides Inhibit Inflammatory Response and Apoptosis of Endothelial and Epithelial Cells in LPS-Induced ALI: A Study Based on Bioinformatic Analysis and in vivo/vitro Experiments

Introduction

Severe inflammatory response leads to poor prognosis of acute lung injury (ALI), the role of gypenosides (GPs) on ALI is not fully clear. The study aimed at investigating the effects of GPs on ALI.

Methods

We firstly established LPS-induced ALI mice model. Then, we tested whether GPs contributed to alleviate inflammatory response and lung injury of ALI in vivo. In order to identify specific mechanisms of the phenomenon, we conducted a bioinformatic analysis of LPS-induced ALI mice based on GEO database to identify hub differentially expressed genes (DEGs). PPI network of the DEGs was used to find hub-genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were conducted based on the DAVID database to identify which pathways the genes enriched. Then, we tested whether GPs inhibited lung injury and inflammatory response via the enriched pathways. We also tested whether GPs inhibited the apoptosis of endothelial and epithelial cells secondary to severe inflammation.

Results

We found GPs significantly alleviated lung injury and improved the survival rate of LPS-induced ALI mice in vivo. Bioinformatic analysis identified 20 hub-genes from DEGs, they were mainly enriched in NF-κB and TNF-α pathways. GPs could reduce the lung injury and inflammatory response via inhibiting NF-κB and TNF-α pathways in vivo. Our results indicated that GPs also inhibited inflammatory response of epithelial and endothelial cells via NF-κB and TNF-α pathways in vitro. Severe inflammatory response could also lead to apoptosis of endothelial and epithelial cells. Our results indicated that GPs effectively inhibited the apoptosis of endothelial and epithelial cells.

Conclusion

Our study suggested GPs contributed to alleviated lung injury in vivo and inhibited inflammation and apoptosis of endothelial and epithelial cells in vitro, providing novel strategies for the prevention and therapy for ALI.

Co-administration of berberine/gypenosides/bifendate ameliorates metabolic disturbance but not memory impairment in type 2 diabetic mice

Cognitive impairment is a well-known complication of Type 2 diabetes mellitus (T2DM) characterized by cellular insulin resistance, chronic inflammation, and metabolic disturbances. Berberine, gypenosides and bifendate are traditional Chinese herbal medicines with multiple pharmacological activities including anti-inflammation, anti-oxidant, metabolism improvement and memory improvement. To investigate whether they have synergistic effect on T2DM metabolic syndrome and associated memory impairment, we measured in this study the effect of a low dose of berberine/gypenosides/bifendate (BGB) co-administration on metabolism and memory performance of T2DM model mice. We found that BGB co-administration ameliorated metabolic abnormalities of both high-fat diet/streptozotocin (STZ)-induced T2DM mice and db/db mice. However, it did not alleviate memory impairment in either type of T2DM model mice. Since neither berberine, gypenosides nor bifendate alone at the low dose is effective, we presume that BGB co-administration has synergistic action on T2DM metabolic syndrome. In addition, our findings suggest that higher doses of BGB might be required to ameliorate memory impairment than metabolic disturbance associated with T2DM.

Quantification of computational fluid dynamics simulation assists the evaluation of protection by Gypenosides in a zebrafish pain model

In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage.

Antidepressive Effect of Arctiin by Attenuating Neuroinflammation via HMGB1/TLR4- and TNF-α/TNFR1-Mediated NF-κB Activation

Inflammation is a potential factor in the pathophysiology of depression. A traditional Chinese herbal medicine, arctiin, and its aglycone, arctigenin, are the major bioactive components in Fructus arctii and exhibit neuroprotective and anti-inflammatory activities. Arctigenin has been reported to have antidepressant-like effects. However, the antidepressant-like effects of arctiin, its precursor, remain unknown. In this study, we investigated the antidepressant-like effects of arctiin and its underlying mechanisms by in vivo and in vitro experiments in mice. Our results showed that arctiin significantly attenuated sucrose consumption and increased the immobility time in tail suspension and forced swimming tests. Arctiin decreased neuronal damage in the prefrontal cortex (PFC) of the brain. Arctiin also attenuated the levels of three inflammatory mediators, indoleamine 2,3-dioxygenase, 5-hydroxytryptamine, and dopamine, that were elevated in the PFC or serum of chronic unpredictable mild stress (CUMS)-exposed mice. Arctiin reduced excessive activation of microglia and neuroinflammation by reducing high mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4)- and tumor necrosis factor-α (TNF-α)/TNF receptor 1 (TNFR1)-mediated nuclear factor-kappa B (NF-κB) activation in the PFC of CUMS-exposed mice and HMGB1- or TNF-α-stimulated primary cultured microglia. These findings demonstrate that arctiin ameliorates depression by inhibiting the activation of microglia and inflammation via the HMGB1/TLR4 and TNF-α/TNFR1 signaling pathways.

Gypenoside Inhibits Endothelial Cell Apoptosis in Atherosclerosis by Modulating Mitochondria through PI3K/Akt/Bad Pathway

Atherosclerosis remains the most common cause of deaths worldwide. Endothelial cell apoptosis is an important process in the progress of atherosclerosis, as it can cause the endothelium to lose their capability in regulating the lipid homeostasis, inflammation, and immunity. Endothelial cell injury can disrupt the integrity and barrier function of an endothelium and facilitate lipid deposition, leading to atherogenesis. Chinese medicine techniques for preventing and treating atherosclerosis are gaining attention, especially natural products. In this study, we demonstrated that gypenoside could decrease the levels of serum lipid, alleviate the formation of atherosclerotic plaque, and lessen aortic intima thickening. Gypenoside potentially activates the PI3K/Akt/Bad signal pathway to modulate the apoptosis-related protein expression in the aorta. Moreover, gypenoside downregulated mitochondrial fission and fusion proteins, mitochondrial energy-related proteins in the mouse aorta. In conclusion, this study demonstrated a new function of gypenoside in endothelial apoptosis and suggested a therapeutic potential of gypenoside in atherosclerosis associated with apoptosis by modulating mitochondrial function through the PI3K/Akt/Bad pathway.

Stress-induced blood brain barrier disruption: Molecular mechanisms and signaling pathways

Stress is a nonspecific response to a threat or noxious stimuli with resultant damaging consequences. Stress is believed to be an underlying process that can trigger central nervous system disorders such as depression, anxiety, and post-traumatic stress disorder. Though the pathophysiological basis is not completely understood, data have consistently shown a pivotal role of inflammatory mediators and hypothalamo-pituitary-adrenal (HPA) axis activation in stress induced disorders. Indeed emerging experimental evidences indicate a concurrent activation of inflammatory signaling pathways and not only the HPA axis, but also, peripheral and central renin-angiotensin system (RAS). Furthermore, recent experimental data indicate that the HPA and RAS are coupled to the signaling of a range of central neuro-transmitter, -mediator and -peptide molecules that are also regulated, at least in part, by inflammatory signaling cascades and vice versa. More recently, experimental evidences suggest a critical role of stress in disruption of the blood brain barrier (BBB), a neurovascular unit that regulates the movement of substances and blood-borne immune cells into the brain parenchyma, and prevents peripheral injury to the brain substance. However, the mechanisms underlying stress-induced BBB disruption are not exactly known. In this review, we summarize studies conducted on the effects of stress on the BBB and integrate recent data that suggest possible molecular mechanisms and signaling pathways underlying stress-induced BBB disruption. Key molecular targets and pharmacological candidates for treatment of stress and related illnesses are also summarized.

Medicinal Value and Potential Therapeutic Mechanisms of Gynostemma pentaphyllum (Thunb.) Makino and Its Derivatives: An Overview

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Gynostemma pentaphyllum (Thunb.) Makino (GpM) and its derivatives, especially gypenosides (Gyps), are widely used as safe and convenient natural herbal drugs for the treatment of many diseases for a long time, and Gyps have different oral bioavailability (OB) values and low ability to cross the blood-brain barrier (BBB). The effects of GpM and isolates on fibrosis, inflammation, oxidation, proliferation and migration are proved. GpM shows bidirectional regulation effect on proliferation, oxidation and apoptosis in tumor and non-tumor cells. GpM and its extractions can resist proliferation, activate oxidation and apoptosis in tumor cells and have opposite effects on non-tumor cells. We succinctly present some current views of medicinal value and potential therapeutic mechanisms of GpM and its derivatives.

Piperlongumine produces antidepressant-like effects in rats exposed to chronic unpredictable stress

Piperlongumine, an alkaloid compound extracted from Peper longum L, has been reported to produce neuroprotective effects in the brain and exert various pharmacological activities such as antitumor, antiangiogenic, anti-inflammatory and analgesic properties. The aim of this study was to investigate the antidepressant-like effects and the possible mechanism of action of piperlongumine in a chronic unpredictable stress (CUS) model. We found that, with venlafaxine as a positive control, orally administered piperlongumine (12.5 and 25 mg/kg) for 7 days, not a single dose, significantly reduced immobility time in the forced swimming test, but did not alter locomotor activity in the open field test, indicating that piperlongumine has antidepressant-like effects without nonspecific motor changes. Then, using the CUS model of depression, piperlongumine was administrated orally for 4 weeks, followed by sucrose preference and forced swimming tests to evaluate the depressive-like behaviors. We found that piperlongumine reversed both the decreased sucrose preference and increased immobility time in rats exposed to CUS. In addition, piperlongumine also reversed the increase in proinflammatory cytokine levels in the hippocampus of rats in the CUS model. Altogether, the present study demonstrated that piperlongumine exhibits the antidepressant-like effects in rats, which may be mediated by the inhibition of the neuronal inflammation in the hippocampus.

Polycyclic polyprenylated acylphloroglucinol and phenolic metabolites from the aerial parts of Hypericum elatoides and their neuroprotective and anti-neuroinflammatory activities

A phytochemical study on the aerial parts of Hypericum elatoides led to the isolation of a previously undescribed polycyclic polyprenylated acylphloroglucinol derivative, hyperelatone A, seven previously undescribed phenolic metabolites, hyperelatones B-H, along with ten known analogues. The structures of hyperelatones A-H were elucidated by 1D and 2D NMR spectroscopy, HRESIMS experiment, single-crystal X-ray diffraction and comparison of experimental and calculated ECD spectra, as well as chemical derivatization. All compounds were evaluated for their neuroprotective activity against hydrogen peroxide (H₂O₂)-induced cell injury in rat pheochromocytoma PC-12 cells and inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells. Hyperelatones B-D and H, cinchonain Ib, and tenuiside A showed noticeable neuroprotection at concentrations of 1.0-100.0 μM. Hyperelatones D, G, and H, (-)-epicatechin, tenuiside A, and (Z)-3-hexenyl-β-D-glucopyranoside exhibited significant anti-neuroinflammatory activity with IC₅₀ values ranging from 0.75 ± 0.02 to 5.83 ± 0.23 μM.