Peony Glycosides Protect Against Corticosterone-Induced Neurotoxicity in PC12 Cells

Neuroprotective effect of Kurarinone against corticosterone-induced cytotoxicity on rat hippocampal neurons by targeting BACE1 to activate P13K-AKT signaling - A potential treatment in insomnia disorder

The hippocampus has been implicated in the pathogenesis of insomnia disorder (ID) and the purpose of this study was to investigate the neuroprotective mechanism of the natural flavone Kurarinone (Kur) on hippocampal neurotoxicity as a potential treatment of ID. The effect of Kur on hippocampal neuronal cell (HNC) viability and apoptosis were assessed by Cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Then, the effect of Kur on β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), brain-derived neurotrophic factor (BDNF), and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) phosphorylation level were measured by Western blot. Further, SwissTargetPrediction analysis and molecular docking experiments were used to detect a potential target of Kur. Then, the p-chlorophenylalanine (PCPA) model was established in vivo to further study the effect of BACE1 expression on Kur and HNC. As a result, HNC viability was only significantly decreased by 2 μM of Kur. Kur reversed the impacts of corticosterone upon inhibiting viability (0.25-1 μM), PI3K (0.5-1 μM)/AKT phosphorylation, and BDNF (1 μM) level, and enhancing the apoptosis (0.25-1 μM) and BACE1 expression (1 μM) in HNCs. BACE1 was a potential target of Kur. Notably, Kur (150 mg/kg) attenuated PCPA-induced upregulation of BACE1 expression in rat hippocampal tissues as ZRAS (0.8 g/kg). The effects of Kur (1 μM) on corticosterone-treated HNCs were reversed by BACE1 overexpression. Collectively, Kur downregulates BACE1 level to activate PI3K/AKT, thereby attenuating corticosterone-induced toxicity in HNCs, indicating that Kur possibly exerted a neuroprotective effect, which providing a new perspective for the treatment of insomnia disorders.

Mechanisms of paeoniaceae action as an antidepressant

Paeoniflorin (PF) has been widely used for the treatment of depression in mice models, some Chinese herbal compound containing PF on treating depression, such as Xiaoyao San, Chaihu-Shugan-San, Danggui Shaoyao San etc. Many experiments are also verifying whether PF in these powders can be used as an effective component in the treatment of depression. Therefore, in this review the antidepressant effect of PF and its mechanism of action are outlined with particular focus on the following aspects: increasing the levels of monoamine neurotransmitters, inhibiting the HPA axis, promoting neuroprotection, enhancing neurogenesis in the hippocampus, and elevating levels of brain-derived neurotrophic factor (BDNF). This review may be helpful for the application of PF in the treatment of depression.

Cytoprotective effects of paeoniflorin are associated with translocator protein 18 kDa

Paeoniflorin (PF) is one of the important active components in peony that are known to produce the neuroprotective effects. However, the involved cytoprotective factors on brain astrocytes are remain unclear. Translocator protein 18 kDa (TSPO) and its downstream neurosteroids biosynthesis play a significant role in cytoprotection. Based on these, the role of TSPO and neurosteroids biosynthesis in the cytoprotective effects of PF is evaluated. The astrocyte cells were cultured and AC-5216 (TSPO ligand) was selected as the positive control drug. The cytoprotective effects of PF and the levels of neurosteroids were quantified by water-soluble tetrazolium assay and enzyme linked immunosorbent assay, respectively. The cytoprotective activities of PF were relevant to neurosteroids (e.g. progsterone and allopregnanolone) biosynthesis, while these effects were totally blocked by PK11195, trilostane and finasteride, respectively. In summary, the cytoprotective effects of PF maybe mediated by TSPO and neurosteroids biosynthesis. The findings may provide the new insights into the cytoprotective effects of PF.

Paeoniflorin Ameliorates Chronic Stress-Induced Depression-Like Behaviors and Neuronal Damages in Rats via Activation of the ERK-CREB Pathway

Neuronal damage is related to the onset and treatment of depressive disorders. Antidepressant-like effects have been elicited by paeoniflorin on animal models. The aim of this study is to demonstrate whether the neuroprotective effect of paeoniflorin on rats suffered from chronic unpredictable mild stress (CUMS) was regulated by the ERK-CREB signaling pathway. Results showed that paeoniflorin not only ameliorated depressive-like behavior with low locomotor activity and prolonged immobility duration in our forced swimming test but also reduced sucrose consumption. Paeoniflorin treatment decreased the degree of neuronal damage in the hippocampus of the model rats. Conversely, it markedly increased the mRNA levels of ERK1, ERK2, and CREB and the levels of ERK, p-ERK, CREB, and p-CREB protein expression in the hippocampus. Blockade of the ERK-CREB axis with the ERK-specific inhibitor U0126 repressed the neuroprotective and antidepressant-like effects of paeoniflorin on rats in the setting of chronic-mild-stress and abolished the recoveries of p-ERK mediated by paeoniflorin treatment. Thus, paeoniflorin possibly exerted a neuroprotective effect modulated by the ERK-CREB signaling pathway on CUMS-induced hippocampal damage in rats.

Metabolomic study of corticosterone-induced cytotoxicity in PC12 cells by ultra performance liquid chromatography-quadrupole/time-of-flight mass spectrometry

Glucocorticoids (GCs) have been proved to be an important pathogenic factor of some neuropsychiatric disorders. Usually, a classical injury model based on corticosterone-induced cytotoxicity of differentiated rat pheochromocytoma (PC12) cells was used to stimulate the state of GC damage of hippocampal neurons and investigate its potential mechanisms involved. However, up to now, the mechanism of corticosterone-induced cytotoxicity in PC12 cells was still looking forward to further elucidation. In this work, the metabolomic study of the biochemical changes caused by corticosterone-induced cytotoxicity in differentiated PC12 cells with different corticosterone concentrations was performed for the first time, using the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS). Partial least squares-discriminate analysis (PLS-DA) indicated that metabolic profiles of different corticosterone treatment groups deviated from the control group. A total of fifteen metabolites were characterized as potential biomarkers involved in corticosterone-induced cytotoxicity, which were corresponding to the dysfunctions of five pathways including glycerophospholipid metabolism, sphingolipid metabolism, oxidation of fatty acids, glycerolipid metabolism and sterol lipid metabolism. This study indicated that the rapid and holistic cell metabolomics approach might be a powerful tool to further study the pathogenesis mechanism of corticosterone-induced cytotoxicity in PC12 cells.

Jiaweisinisan facilitates neurogenesis in the hippocampus after stress damage

The traditional Chinese medicine Jiaweisinisan has antidepressant effects, and can inhibit hypothalamus-pituitary-adrenal gland axis hyperactivity in stress-induced depression. In this study, rat hippocampal neural precursor cells were cultured in serum-free medium in vitro and a stress damage model was established with 120 μM corticosterone. Cells were treated with 10% (v/v) Jiaweisinisan drug-containing serum and the corticosterone antagonist RU38486. Results of the 3-(4,5-dimethylthiazol-2-yl)-3,5-di-phenytetrazoliumromide assay showed that both Jiaweisinisan drug-containing serum and RU38486 promoted the proliferation of neural precursor cells after corticosterone exposure. Immunofluorescence detection showed that after Jiaweisinisan drug-containing serum and RU38486 treatment, the 5-bromo-2-deoxyuridine/terminal deoxynucleotidyl transferase dUTP nick end labeling ratio in hippocampal neural precursor cells significantly increased, and the apoptotic rates of glial cells reduced, and neuron-like cell differentiation from neural precursor cells significantly increased. Our experimental findings indicate that Jiaweisinisan promotes hippocampal neurogenesis after stress damage.

Cajaninstilbene acid protects corticosterone-induced injury in PC12 cells by inhibiting oxidative and endoplasmic reticulum stress-mediated apoptosis

It has been reported that high corticosterone level could damage the normal hippocampal neurons both in vitro and in vivo. Furthermore, high concentration of corticosterone induced impair in PC12 cells has been widely used as in vitro model to screen neuroprotective agents. Cajaninstilbene acid (CSA), a natural stilbene isolated from Cajanus cajan leaves, has various activities. In present study, we investigated the effect of CSA on corticosterone-induced cell apoptosis and explored its possible signaling pathways in PC12 cells. We demonstrated that pretreatment with CSA at the concentrations of 1-8 μmol/L remarkably reduced the cytotoxicity induced by 200 μmol/L of corticosterone in PC12 cells by MTT, and further confirmed the neuroprotection by Hoechst 33342 and PI double staining and lactate dehydrogenase release (LDH) assay at the concentration of 8 μmol/L. Moreover, the cytoprotection of CSA was proved to be associated with the homeostasis of intracellular Ca(2+), relieving corticosterone-induced oxidative stress by decreasing the contents of ROS and malondialdehyde (MDA), increasing the activities of superoxide dismutase (SOD) and catalase (CAT), and the stabilization of ER stress via down-regulating the expression of ER chaperone protein glucose-regulated protein 78 (GRP78), ER stress associated transcription factor C/EBP homologous protein (CHOP/GADD153), and the X box-binding protein-1 (XBP-1), as well as the expression of ER stress-specific protein caspase-12 and its downstream protein caspase-9. Considering all the findings, it is suggested that the neuroprotective activity of CSA against the impairment induced by corticosterone in PC12 cells was through the inhibition of oxidative stress and ER stress-mediated pathway.

The Antidepressant-like Effect of Ethanol Extract of Daylily Flowers ( Jīn Zhēn Huā) in Rats

According to the prediction of the 2008 World Health Organization (WHO) report, depression will be the highest burden disease by the year 2030. Daylily flower ( Jīn Zhēn Huā ; the flower of Hemerocallis fulva) is traditionally used for soothing in Chinese dietary therapy. The major flavonoid of daylily flowers, rutin, is also characterized to be an antidepressant. In this study, we investigated the antidepressant effects of ethanol extract of daylily flowers (DFEtoH) and rutin by forced swimming test (FST) and neurotransmitter metabolism of brain regions (frontal cortex, hippocampus, striatum, and amygdala). Results show that either short- or long-term tests, the extract and rutin significantly reduce the immobility time and increased swimming time of FST, which are compared with the vehicle (P < 0.05). The extract and rutin also increase the serotonin, norepinephrine, and dopamine concentration of these brain regions (P < 0.05). In long-term tests, the daylily flowers extract markedly increased serotonin concentration and reduced serotonin turnover rate in these brain regions but not frontal cortex. In conclusion, present data illustrated that DFEtoH does have antidepressant-like effects possibly via the regulation of serotonergic system. Moreover, rutin might be playing a very important role in the antidepressant-like effects of DFEtoH.

Rosmarinus officinalis polyphenols produce anti-depressant like effect through monoaminergic and cholinergic functions modulation

Rosmarinus officinalis (R. officinalis), a culinary aromatic and medicinal plant, is very rich in polyphenols and flavonoids with high antioxidant properties. This plant was reported to exert multiple benefits for neuronal system and alleviate mood disorder. In our previous study, we demonstrated that R. officinalis and its active compounds, luteolin (Lut), carnosic acid (CA), and rosmarinic acid (RA), exhibited neurotrophic effects and improved cholinergic functions in PC12 cells in correlation with mitogen-activated protein kinase (MAPK), ERK1/2 signaling pathway. The current study was conducted to evaluate and understand the anti-depressant effect of R. officinalis using tail suspension test (TST) in ICR mice and PC12 cells as in vitro neuronal model. Proteomics analysis of PC12 cells treated with R. officinalis polyphenols (ROP) Lut, CA, and RA revealed a significant upregulation of tyrosine hydroxylase (TH) and pyruvate carboxylase (PC) two major genes involved in dopaminergic, serotonergic and GABAergic pathway regulations. Moreover, ROP were demonstrated to protect neuronal cells against corticosterone-induced toxicity. These results were concordant with decreasing immobility time in TST and regulation of several neurotransmitters (dopamine, norepinephrine, serotonin and acetylcholine) and gene expression in mice brain like TH, PC and MAPK phosphatase (MKP-1). To the best of our knowledge this is the first evidence to contribute to the understanding of molecular mechanism behind the anti-depressant effect of R. officinalis and its major active compounds.

The antidepressant-like effects of paeoniflorin in mouse models

Peony is often used in Chinese herbal medicine for the treatment of depression-like disorders. Our previous studies have demonstrated that the total glycosides of peony exert antidepressant-like effects in animal models. Paeoniflorin is the main active glycoside of peony. The aim of this study was to evaluate the antidepressant-like effects of paeoniflorin in mice, as well as its active mechanisms. The results revealed that intraperitoneally injected paeoniflorin significantly reduced the duration of immobility in forced swimming and tail suspension tests. The doses that affected the immobility response did not affect locomotor activity. Furthermore, paeoniflorin antagonized reserpine-induced ptosis, akinesia and hypothermia. Paeoniflorin also significantly increased the levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus. These results suggest that the upregulation of serotonergic systems may be an important mechanism for the antidepressant-like effects of paeoniflorin in mice.

Anti-depressant-like effect of peony: a mini-review

CONTEXT

Depression is a common psychiatric disorder, yet the clinical efficacy of antidepression therapies is unsatisfactory. Thus, the search for new anti-depressants continues, and natural products remain a promising source of new therapeutic agents. The root part of Paeonia lactiflora Pall. (Ranunculaceae), known as peony, is often used in Chinese herbal prescriptions for the treatment of depression-like disorders.

OBJECTIVES

The objective of this review is to provide scientific evidence to support further research on peony as a potential anti-depressant drug.

METHODS

This review summarizes the results obtained in our laboratory, together with other literature data obtained through a comprehensive search in databases including PubMed, ScienceDirect, Scirus, and Web of Science.

RESULTS

The peony extract is active in the mouse forced swim test and tail suspension test, and it produces anti-depressant effects in chronic unpredictable mild stress-induced depression model in mice and rats. The anti-depressant mechanisms of peony are likely mediated by the inhibition of monoamine oxidase activity, neuro-protection, modulation of the function of hypothalamic-pituitary-adrenal axis, inhibition of oxidative stress, and the up-regulation of neurotrophins.

CONCLUSIONS

Peony is used clinically to treat depression-like symptoms in Chinese medicine, and it has been shown to possess anti-depressant property in a battery of test models using laboratory animals. Its effect is likely mediated by multiple targets. Further studies are warranted to delineate the molecular mechanisms of action, determine the pharmacokinetics, establish the toxicological profile, and assess the potentials of peony in clinical applications. Identification of the clinically active ingredient(s) is also warranted.

Protective effects of paeoniflorin against corticosterone-induced neurotoxicity in PC12 cells

Neuroprotection has been proposed as one of the acting mechanisms of antidepressants. Paeoniflorin, a monoterpene glycoside, has been reported to display antidepressant-like effects in animal models of behavioural despair. The present study aimed to examine the protective effect of paeoniflorin treatment on corticosterone-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. Paeoniflorin was shown to elevate cell viability, decrease levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) in corticosterone-treated PC12 cells. Paeoniflorin also reversed the reduced nerve growth factor (NGF) mRNA level caused by corticosterone in PC12 cells. The results suggest that paeoniflorin exerts a neuroprotective effect on corticosterone-induced neurotoxicity in PC12 cells, at least in part, via the inhibition of oxidative stress and the up-regulation of NGF expression. This neuroprotective effect may be one of the action pathways that accounts for the in vivo antidepressant activity of paeoniflorin.

Protective effects of peony glycosides against corticosterone-induced cell death in PC12 cells through antioxidant action

AIM OF THE STUDY

Previous studies in our laboratory have shown that total glycosides of peony (TGP) produced antidepressant-like action in various mouse models of behavioral despair. However, the molecular mechanism by which TGP exerts antidepressant-like effect is not fully understood. This study examined the protective effects of TGP against corticosterone-induced neurotoxicity in rat pheochromocytoma (PC12) cells and ts possible mechanisms.

MATERIALS AND METHODS

The direct antioxidant effect of TGP was investigated by using a 2,2'-azinobis-(3-ethylbenzothiazoline- 6-sulphonic acid) (ABTS) radical cation-scavenging assay in a cell-free system. PC12 cells were treated with 200 μM of corticosterone in the absence or presence of TGP in varying concentrations for 48 h. Cell viability, lactate dehydrogenase (LDH) activity, intracellular reactive oxygen species (ROS) level, malondialdehyde (MDA) content, glutathione (GSH) content, superoxide dismutase (SOD) activity, and catalase (CAT) activity were then determined.

RESULTS

TGP displayed antioxidant properties in the cell-free system, and the IC50 value in the ABTS radical cation-scavenging assay was 9.9 mg/L. TGP treatment at increasing doses (1-10 mg/L) protected against corticosterone-induced cytotoxicity in PC12 cells in a dose-dependent manner. The cytoprotection afforded by TGP treatment was associated with decreases in the intracellular ROS and MDA levels, and increases in the GSH level, SOD activity, and CAT activity in corticosterone-treated PC12 cells.

CONCLUSION

The results suggest that TGP has a neuroprotective effect on corticosterone-induced neurotoxicity in PC12 cells, which may be related to its antioxidant action.

Paeoniflorin protects against NMDA-induced neurotoxicity in PC12 cells via Ca2+ antagonism

Preclinical and clinical investigation has shown that hippocampal neuronal atrophy and destruction can be observed in patients with depression, and this can be ameliorated with antidepressant medication. Neuroprotection has therefore been proposed as one of the mechanisms of action of antidepressants. Paeoniflorin, a monoterpene glycoside, has been reported to display antidepressant-like effects in animal models of behavioral despair. The present study aimed to examine the protective effect of paeoniflorin treatment on N-methyl-D-aspartate (NMDA)-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. Paeoniflorin was shown to elevate cell viability, decrease lactate dehydrogenase (LDH) release in NMDA-treated PC12 cells. Paeoniflorin also reversed the increased intracellular calcium (Ca(2+)) concentration and the reduced Calbindin-D28K mRNA level caused by NMDA in PC12 cells. These results suggest that paeoniflorin exerts a neuroprotective effect on NMDA-induced neurotoxicity in PC12 cells, at least in part, via Ca(2+) antagonism.

Protective effects of paeoniflorin against glutamate-induced neurotoxicity in PC12 cells via antioxidant mechanisms and Ca(2+) antagonism

Preclinical and clinical investigations have shown hippocampal neuronal atrophy and destruction were observed in patients with depression, which could be ameliorated by the treatment with antidepressants. Therefore, neuroprotection has been proposed to be one of the acting mechanisms of antidepressant. Paeoniflorin, a monoterpene glycoside, has been reported to display antidepressant-like effects in animal models of behavioral despair. The present study aimed to examine the protective effect of paeoniflorin on glutamate-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The results showed that pretreatment with paeoniflorin elevated cell viability, inhibited apoptosis, decreased levels of intracellular reactive oxygen species and malondialdehyde, and enhanced activity of superoxide dismutase in glutamate-treated PC12 cells. Pretreatment with paeoniflorin also reversed the increased intracellular Ca(2+) concentration and the reduced Calbindin-D28K mRNA level caused by glutamate in PC12 cells. The results suggest that paeoniflorin exerts a neuroprotective effect on glutamate-induced neurotoxicity in PC12 cells, at least in part, via inhibiting oxidative stress and Ca(2+) overload. This neuroprotective effect may be one of the action pathways accounting for the in vivo antidepressant activity of paeoniflorin.