Tandem mass tag-based quantitative proteomic analysis of the liver reveals potential protein targets of Xiaochaihutang in CUMS model of depression

Depression is a global mental disorder disease and greatly threatened human health. Xiaochaihutang (XCHT) has been used successfully in treatment of depression for many years in China, but the mechanism is unclear. Using the chronic unpredictable mild stress (CUMS) mice model of depression, the present study aimed to reveal possible antidepressant mechanisms of XCHT from the perspective of liver by analyzing hepatic proteomics in mice. Bioinformatics analysis identified 31 differentially expressed proteins (DEPs), including 5 upregulated and 26 downregulated proteins, between the CUMS model and XCHT groups. The bile secretion pathway was found by KEGG pathway analysis of these DEPs. Four of the 31 differentially expressed proteins, including 2 active proteins involved in bile secretion, carbonic anhydrase 2 (CA2) and cystic fibrosis transmembrane conductance regulator (CFTR), were selected to verify their genes. Four genes (Cyp7a1, Fxr, Shp and Ntcp) related to bile acid synthesis and transport were further investigated by quantitative real-time polymerase chain reaction (qRT-PCR). Both biochemical tests and gene studies demonstrated that CUMS affected bile acid synthesis and transport, while XCHT regulated this pathway. The results indicated that there may be a potential relationship between CUMS induced depression and hepatic injury caused by increased bile acid, and also provide a novel insight to understand the underlying anti-depression mechanisms of XCHT.

Xiaochaihutang Improves the Cortical Astrocyte Edema in Thioacetamide-Induced Rat Acute Hepatic Encephalopathy by Activating NRF2 Pathway

Oxidative stress induced by high ammonia, which leads to astrocyte edema, is the key to acute hepatic encephalopathy (AHE). Nuclear factor erythroid 2-related factor 2 (NRF2) has been implicated in oxidative stress, but the mechanism of NRF2 against ammonia-induced astrocytes edema has not been fully studied. We confirmed that the NRF2 pathway is related to brain edema caused by AHE and found that Xiaochaihutang (XCHT) could effectively activate the NRF2 pathway to treat AHE. The model of AHE was established with thioacetamide (TAA) in rats. Rat behaviors were observed, brain water content, blood ammonia levels, glutamine synthetase (GS), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) were determined after XCHT treatment. Furthermore, the expression of NRF2 pathway proteins and mRNA, glial fibrillary acidic protein (GFAP) and aquaporins 4 (AQP4) were examined. In order to determine whether XCHT has a direct effect on cerebral edema caused by high ammonia, we examined the effect of XCHT compound serum on cortical astrocytes in the presence of ammonia, through microscopic observation and immunofluorescence (IF). Results showed that AHE induced by TAA changed the behavior of the rats, and increased brain water content, blood ammonia levels, GS and MDA content meanwhile decreasing T-SOD, but these symptoms were improved by treatment with XCHT. XCHT protected brain edema by activating the NRF2 pathway and increasing the expression of downstream proteins and genes. Astrocytes treated with 5 mM ammonia also showed an increase in the AQP4 protein expression but a decrease in XCHT compound serum and ammonia-induced cell edema groups. This study demonstrates that the NRF2 pathway is involved in the brain edema in AHE, and XCHT may represent a useful prescription for the treatment of AHE.

Antidepressant-like effects of Xiaochaihutang in perimenopausal mice

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT) is a traditional Chinese medicine prescription for thousand years in China. Our previous researches show that XCHT has antidepressant-like effects in several depression models, but effect and mechanism of XCHT in perimenopausal depression are still vague.

AIM OF THE STUDY

To reveal the antidepressant-like effect and mechanism of XCHT in perimenopausal mice.

MATERIALS AND METHODS

Perimenopausal depression model is executed by ovariectomy combined with chronic unpredictable mild stress (OVX-CUMS). Tail suspension test (TST), forced swim test (FST), elevated plus-maze (EPM), novelty suppressed feeding (NSF) and locomotor activity are used to assess antidepressant-like effects of XCHT. The Level of estradiol (E₂), follicle-stimulating hormone (FSH), gonadotrophin releasing hormone (GnRH), corticosterone (CORT), adrenocorticotrophic hormone (ACTH) and corticotropin releasing hormone (CRH) are evaluated by ELISA. Antidepressant mechanisms of XCHT in OVX-CUMS mice are analyzed by 5-hydroxytryptamine (5-HT), tryptophan hydroxylase 2 (TPH2) and estrogen receptor α and β (ERα/β).

RESULTS

The results show that OVX-CUMS significantly increases the immobility time in TST and FST, increases latency to feed, decreases food consumption in NSF and both the time spend and number of entries in open arms in EPM. While, oral administration of XCHT can significantly normalize above depression-like behaviors in OVX-CUMS mice. Moreover, XCHT also remarkably normalized levels of 5-HT, 5-HIAA, E₂, GnRH, CORT, ACTH and CRH in OVX-CUMS mice. Finally, the expression of ERβ and TPH2 are decreased by OVX-CUMS in prefrontal cortex and hypothalamus, and XCHT can restore these decrease.

CONCLUSION

Current findings suggest XCHT can alleviate perimenopausal depression-like behaviors, restore 5-HT and hormones in OVX-CUMS mice, which may be related to normalizing the functions of HPA/HPO axis and enhancing expression of ERβ and TPH2 in prefrontal cortex and hypothalamus.

Quantitative proteomics reveal antidepressant potential protein targets of xiaochaihutang in corticosterone induced model of depression

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT), one of famous Chinese herbal prescription for treating Shaoyang symptom, has been used successfully in depressive disorders for many years. Our laboratory has demonstrated that XCHT remarkably alleviated various depressive behaviors induced by several depressive animal models, but previous studies only focused on one or several protein targets, lacked dynamic change and interrelation of proteins. Therefore, potential protein targets and mechanisms are required further systematic investigation.

AIM OF THE STUDY

To discover and assess the differentially expressed proteins (DEPs) of hippocampus after oral administration of XCHT in corticosterone (CORT) induced model of depression by using isobaric tags for relative and absolute quantification (iTRAQ) analysis.

MATERIALS AND METHODS

The antidepressant effects of XCHT were assessed by two behavioral despair models (forced swimming test and tail suspension test) in CORT induced model of depression. The DEPs of hippocampus after XCHT treatment were investigated by iTRAQ analysis. Potential protein targets and mechanisms were assessed by gene ontology (GO), Kyoto encyclopedia of gene and genomes (KEGG) and protein-protein interaction (PPI) network.

RESULTS

Our data demonstrated XCHT could significantly improve depressive behaviors. A total of 241 DEPs were identified after XCHT treatment, including 68 up regulation and 173 down regulation proteins. GO enrichment results indicated that XCHT mainly regulated intracellular structural proteins involved in cellular response to stress, transferase activity and steroid hormone. KEGG enrichment analysis showed that endocytosis might be the principal pathway of XCHT on depression. PPI analysis predicted cell division cycle and apoptosis regulator protein 1 (Ccar1) and Calretinin (Calb2) might play the central roles in XCHT's antidepressant network.

CONCLUSION

Our results indicate that XCHT plays the important roles in antidepressant action by restoring DEPs, which results in the dysregulation of hippocampal neurogenesis, neurotransmitter and steroid hormone. The current results wish to provide novel perspectives for revealing the potential protein targets of XCHT on depression.

Xiaochaihutang Inhibits the Activation of Hepatic Stellate Cell Line T6 Through the Nrf2 Pathway

Xiaochaihutang (XCHT) is one of classic prescriptions in Treatise on Febrile Diseases in China which was reported to have the effect of anti-hepatic fibrosis in vivo. Activation of hepatic stellate cells (HSCs) is now well established as a central driver of fibrosis in liver injury. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important element for anti-oxidative damage which is one of the key factors responsible for occurrence. This study was to investigate the effect of XCHT compound serum on HSCs activation and focus on the Nrf2 pathway. Rats in treatment groups were given the appropriate doses of XCHT granules (5 g/kg) and Silybin (50 mg/kg) for 6 days, and the serum were obtained. The compound serum was used to intervene HSCs. The results found that XCHT compound serum significantly inhibited the proliferation of HSCT6 cells. The number of α-SMA positive stained cells in HSCT6 cells and the content of Collagen type I (collagen-I) in supernatant were significantly decreased indicating suppression of activated HSCs. Compared with the control group, the nuclear transcription of Nrf2 and the expressions of Nqo1, GCLC, and GCLM were significantly increased in XCHT group. However, the effects of XCHT were inhibited in Nrf2-siRNA transfected HSCT6 cells. These studies demonstrated that XCHT could inhibit HSCT6 cell proliferation and activation. The mechanism might be related to up-regulation of the Nrf2 pathway against oxidative stress.

Xiaochaihutang attenuates depressive/anxiety-like behaviors of social isolation-reared mice by regulating monoaminergic system, neurogenesis and BDNF expression

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT), as a classical herbal formula for the treatment of "Shaoyang syndrome" has been demonstrated to exert an antidepressant effect in multiple animal models of depression as shown in our previous studies. However, the effects of XCHT on social isolation (SI)-reared mice have not been investigated. This study aims to explore the effects of XCHT on depressive/anxiety-like behaviors of SI-reared mice, and its implicated mechanisms, including alterations in the monoaminergic system, neurogenesis and neurotrophin expression.

MATERIALS AND METHODS

Male C57 BL/6J mice (aged 4 weeks after weaning) were reared isolatedly for 8 weeks and XCHT (0.8, 2.3, 7.0g/kg) were given by gavage once a day. Forced swimming test (FST), tail suspension test (TST), open field test (OFT), elevated-plus maze test (EPM) and intruder-induced aggression test were used to explore the effects of XCHT on depressive/anxiety-like behaviors of SI-reared mice after administration of XCHT for 6 weeks. HPLC-MS/MS was performed to quantify the levels of neurotransmitters in the hippocampus by in vivo microdialysis, while western immunoblotting was used to evaluate the action of XCHT on the synthesis, transport and degradation of monoamine neurotransmitters. Immunofluorescence was used to study the effects of XCHT on neurogenesis and neurotrophin expression, including Ki-67, DCX, BrdU and BDNF.

RESULTS

Our results showed that administration of XCHT (0.8, 2.3 and 7.0g/kg) for 6 weeks significantly attenuated the increase in immobility time in TST and FST, improved the anxiety-like behaviors in OFT and EPM, and improved the aggressive behaviors of SI-reared mice. XCHT significantly elevated monoamine neurotransmitters levels and inhibited 5-HT turnover (5-HIAA/5-HT) in hippocampal microdialysates of SI-reared mice. In addition, we found XCHT enhanced monoamine neurotransmitter synthesis enzymes (TPH2 and TH) expressions, inhibited serotonin transporter (SERT) expression and decreased monoamine neurotransmitter degradation enzyme (MAO_A) expression in the hippocampus of SI-reared mice for the first time. Moreover, XCHT significantly augmented hippocampal neurogenesis and BDNF expression in hippocampus of SI-reared mice.

CONCLUSIONS

Our results showed for the first time that XCHT improved depressive/anxiety-like behaviors of SI-reared mice by regulating the monoaminergic system, neurogenesis and neurotrophin expression. The findings indicate that XCHT may have a therapeutic application for early-life stress model of depression and in turn provide further evidence supporting XCHT a novel potential antidepressant from a distinct perspective.

Antidepressant-like effects of Xiaochaihutang in a neuroendocrine mouse model of anxiety/depression

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis is often observed in the pathophysiology of depression. Antidepressant therapy can restore hippocampal neurogenesis to rescue the HPA axis regulation defects. Xiaochaihutang (XCHT), a famous Chinese herbal formula, has been used clinically in depressive disorders in China. Our previous studies have demonstrated XCHT improved depressive-like behaviors in chronic unpredictable mild stress rat, but the underlying mechanisms of XCHT on hippocampal neurogenesis and the HPA axis were still unclear.

MATERIALS AND METHODS

We used chronic corticosterone (CORT)-induced mouse model of anxiety/depression to investigate antidepressant-like effects of XCHT by several physical and behavioral testing, including body weight, coat state, open field test, elevated plus maze, tail suspension test and forced swimming test. The integrity of negative feedback function on HPA axis was assessed by the dexamethasone (DEX) suppression test. In addition, Ki-67 and doublecortin (DCX) were performed to assess hippocampal cell proliferation and neurogenesis by immunohistochemistry. Chemical profile of active constituents in brain after oral administration of XCHT was revealed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

RESULTS

Our results showed that oral administration of XCHT (2.3, 7 and 21g/kg) for 30 days remarkably normalized chronic CORT-induced the slowness in weight gain, the deterioration in coat state, the escape behavior in open field test and elevated plus maze, and the increase of immobility time in tail suspension test and forced swimming test. Moreover, XCHT significantly reversed chronic CORT-induced the reduction of DEX-induced plasma corticosterone/c-Fos suppression and Ki-67/DCX positive cells. Finally, a total 13 potential active constituents in brain were identified by UPLC-MS/MS after oral administration of XCHT, including 10 prototype components and 3 metabolites.

CONCLUSIONS

Our findings showed that XCHT could remarkably alleviate chronic CORT-induced anxiety/depression-like behaviors, which were probably attribute to promoting hippocampal neurogenesis and remodeling the integrity of the negative feedback loop on HPA axis. The constituents identified in brain might contribute to understanding the therapeutic basis of XCHT on depression.

Analysis of main constituents and mechanisms underlying antidepressant-like effects of Xiaochaihutang in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT), a famous Chinese herbal formula which consists of seven Chinese herbs, has been used clinically in depressive disorders in China. Our previous studies have demonstrated that XCHT improved depressive-like behavior in several animal models of depression. However, therapeutic basis of XCHT on depression are challenging, due to the complex active constituents of XCHT and the unclear pharmacological mechanism of action.

MATERIALS AND METHODS

To provide further insights into therapeutic basis of XCHT, the core in compatibility of XCHT on antidepressant therapy was assessed by the method of orthogonal array design. The comparative evaluations on antidepressant effects of XCHT and its core in compatibility were executed by tail suspension test (TST), forced swim test (FST), novelty suppressed feeding test (NSFT), reserpine-induced hypothermia and palpebral ptosis. Moreover, the potential mechanism was explored by investigating levels of monoamine neurotransmitters in hypothalamus and striatum and neurogenesis in hippocampus. Chemical profile of active constituents in plasma after oral administration of the core in compatibility of XCHT was revealed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

RESULTS

The results of orthogonal array design experiment showed that Huangqin (Radix scutellariae), Renshen (Ginseng) and Gancao (Radix glycyrrhizae), defined as HRG, might be the core in compatibility of XCHT on antidepressant therapy. In accordance with XCHT, oral administration of HRG for 15 days significantly reduced immobility duration in TST and FST without affecting locomotor activity. Both HRG and XCHT increased immobility latency in FST, decreased the latency in NSFT, reversed reserpine-induced hypothermia and palpebral ptosis. Moreover, both HRG and XCHT significantly increased levels of 5-HT and DA in hypothalamus. In addition, HRG could remarkably increase Ki-67 and doublecortin (DCX) positive cells in hippocampus. A total 25 active constituents in plasma, including 14 prototype components and 11 metabolites, were identified by UPLC-MS/MS after oral administration of HRG.

CONCLUSION

The present results reveal that HRG is supposed to be the core in compatibility of XCHT on antidepressant therapy. In accordance with XCHT, HRG exerts significant antidepressant-like effects, which are likely attributed to regulating serotonergic and dopaminergic systems and increasing hippocampal neurogenesis. The constituents identified in plasma after oral administration of HRG may be the potential active ingredients for the treatment of depression.

Antidepressant-like effects of Xiaochaihutang in a rat model of chronic unpredictable mild stress

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT) has been used in China for thousands of years to treat "Shaoyang syndrome", which involves depressive-like symptoms. However, few studies have investigated its antidepressant effects and pharmacological mechanism of action. The present study was designed to confirm the antidepressant effect of XCHT using a chronic unpredictable mild stress (CUMS) model and explore its potential mechanism of action by investigating the monoamine neurotransmitters (dopamine and 5-hydroxytryptamine) and neurotrophins (BDNF and NGF).

MATERIALS AND METHODS

The CUMS model was established in rats, and the antidepressant effect of XCHT (0.6, 1.7 and 5mg/kg/day, given by gastric gavage for 4 weeks) was investigated using the open field test (OFT), food consumption test and sucrose preference test. The concentrations of 5-HT and DA in the hippocampus were measured by high performance liquid chromatography with electrochemical detection (HPLC-ECD). The expressions of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and their receptors tyrosine receptor kinase B (TrkB) and tyrosine receptor kinase A (TrkA) in the hippocampus were measured by immunohistochemical staining analysis.

RESULTS

CUMS caused a significant decrease in OFT, food consumption and sucrose preference in rats, and these depression-like behaviors were significantly improved by XCHT (1.7 and 5 g/kg/day). Moreover, XCHT significantly increased the concentrations of 5-HT (0.6 and 5 g/kg/day) and DA (5 g/kg/day), and improved the BDNF, NGF, TrkB and TrkA expressions in the hippocampus (1.7 and 5 g/kg/day), which was reduced in CUMS rats.

CONCLUSION

The results obtained suggested that XCHT may have therapeutic actions on depression-like behavior induced by CUMS in rats possibly mediated by increasing the monoamine neurotransmitter concentration and neurotrophin expression in the hippocampus.