RNA sequencing analysis of gene expression in rat hippocampus exposed to chronic stress and albiforin treatment
ABSTRACT: We performed high-throughput profiling of gene expression in rat hippocampus in response to chronic unpredictable mild stress (CUMS) and albiflorin treatment. Total 415 differentially expressed genes (DEGs) were identified in rat hippocampus in response to albiflorin treatment compared with CUMS rats treated with saline (CUMS-Sal). We conducted the integrated metabolomics and transcriptomics analysis and found the correction of 16 biochemical pathways by albiflorin such as sphingolipids, phospholipids, tryptophan metabolism, fatty acid oxidation, and purine and pyrimidine metabolism. Our study provided deep insights into the understanding of the molecular mechanisms underlying the rapid antidepressant actions of albiflorin. Overall design: Rats were exposed to chronic unpredictable mild stress (CUMS) for 5-weeks. At the last week of the exposure, rats were treated with saline, fluoxetine (7 mg/kg/d) or albiflorin (7 mg/kg/d) for 7 days. Total 4 groups were set up: rats without CUMS exposure and with saline treatment (Control-Sal), rats received CUMS and saline (CUMS-Sal), rats received CUMS and fluoxetine (CUMS-Flx) and rats received CUMS and albiflorin (CUMS-Alb). Three replicates were used for each group.
Project description:Background: The apelin-APJ system has been considered to play a crucial role in HPA axis function, and how the traditional Chinese compound prescription Xiaoyaosan regulates the apelin-APJ system as a supplement to treat depressive disorders. Objective: To investigate the depression-like behaviors and expression of apelin and APJ in hypothalamus of chronic unpredictable mild stress (CUMS) mice and study whether these changes related to the regulation of Xiaoyaosan. Methods: 60 adult C57BL/6J mice were randomly divided into four groups, including control group, CUMS group, Xiaoyaosan treatment group and fluoxetine treatment group. Mice in the control group and CUMS group received 0.5 mL physiological saline once a day by intragastric administration. Mice in two treatment groups received Xiaoyaosan (0.25 g/kg/d) and fluoxetine (2.6 mg/kg/d), respectively. After 21 days of modeling with CUMS, the expression of apelin and APJ in hypothalamus were measured by real-time fluorescence quantitative PCR, western blot and immunohistochemical staining. The physical condition, body weight, food intake and behavior tests such as open field test, sucrose preference test and force swimming test were measured to evaluate depressive-like behaviors. Results: In this study, significant behavioral changes were found in CUMS-induced mice, meanwhile the expressions of apelin and APJ in the hypothalamus were changed after modeling. The body weight, food-intake and depressive-like behaviors in CUMS-induced mice could be improved by Xiaoyaosan treatment which is similar with the efficacy of fluoxetine, while the expressions of apelin and APJ in hypothalamus were modified by Xiaoyaosan. Conclusions: The data suggest that apelin-APJ system changes in the hypothalamus may be a target of depressive disorders, and the beneficial effects of Chinese compound prescription Xiaoyaosan on depressive-like behaviors may be mediated by the apelin-APJ system.
Project description:Depression is considered a widespread neuropsychiatric disease associated with neuronal injury within specific brain regions. Fluoxetine, a selective serotonin reuptake inhibitor, has been widely used in depressed patients. Recently, fluoxetine has demonstrated neuroprotective effects apart from the effect on serotonin. However, the underlying mechanism involved in this neuroprotection remains unclear, in particular, whether fluoxetine exerts antidepressant effects via protecting against neuronal injury. Here, we found that treatment with fluoxetine (10 mg/kg, i.p.) for 2 weeks ameliorated depression-like behaviors in a chronic unpredictable mild stress (CUMS)-induced rat model of depression and was accompanied with an alleviation of glia activation and inhibition of interleukin-1? (IL-1?), interferon gamma (IFN-?), and tumor necrosis factor-? (TNF-?) expression in the hippocampal dentate gyrus (DG) region. Meanwhile, CUMS rats treated with fluoxetine showed reductions in neuronal apoptosis and a downregulation of the apoptotic protein Bax, cleaved caspase 3, and caspase 9 levels. These effects appear to involve a downregulation of p38 mitogen-activated protein kinase (MAPK) signaling within the DG hippocampus as the specific inhibitor of p38 MAPK, SB203580, significantly suppressed apoptosis, as well as ameliorated depressive behaviors resulting from CUMS exposure. Moreover, fluoxetine could rescue neuronal deterioration and depression-like phenotypes caused by overexpression of p38 in DG. This finding extends our knowledge on the antidepressant-like effects of fluoxetine, which appear to at least partially profit from neuroprotection against inflammation and neuronal apoptosis via downregulation of the p38 MAPK pathway. The neuroprotective mechanisms of fluoxetine may provide some novel therapeutic avenues for stress-related neurological diseases.
Project description:Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus.
Project description:Although ketamine shows a rapid and sustained antidepressant effect, the precise mechanisms underlying its effect are unknown. Recent studies indicate a key role of p11 (also known as S100A10) in depression-like behavior in rodents. The present study aimed to investigate the role of p11 in the antidepressant-like action of ketamine in chronic unpredictable mild stress (CUMS) rat model. The open-field test, forced swimming test and sucrose preference test were performed after administration of ketamine (10 mg kg(-1)) or a combination of ketamine and ANA-12 (a tropomyosin-related kinase B (TrkB) antagonist; 0.5 mg kg(-1)). The lentivirus vector for p11 was constructed to knock down the hippocampal expression of p11. In the CUMS rats, ketamine showed a rapid (0.5 h) and sustained (72 h) antidepressant effect, and its effect was significantly blocked by co-administration of ANA-12. Furthermore, ketamine significantly increased the reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus of CUMS rats, whereas ketamine did not affect the expression of p11 in CUMS rats 0.5 h after administration. In addition, ketamine significantly increased the reduced ratio of p-TrkB/TrkB in the hippocampus by CUMS rats, and its effect was also blocked by ANA-12. Moreover, the reduced expression of BDNF and p11 in the hippocampus of CUMS rats was significantly recovered to control levels 72 h after ketamine administration. Interestingly, knockdown of hippocampal p11 caused increased immobility time and decreased sucrose preference, which were not improved by ketamine administration. These results suggest that p11 in the hippocampus may have a key role in the sustained antidepressant effect of ketamine in the CUMS model of depression.
Project description:The PP2C family member Wild-type p53-induced phosphatase 1 (Wip1) critically regulates DNA damage response (DDR) under stressful situations. In the present study, we investigated whether Wip1 expression was involved in the regulation of DDR-induced and depression-related cellular senescence in mouse hippocampus. We found that Wip1 gene knockout (KO) mice showed aberrant elevation of hippocampal cellular senescence and of ?-H2AX activity, which is known as a biomarker of DDR and cellular senescence, indicating that the lack of Wip1-mediated ?-H2AX dephosphorylation facilitates cellular senescence in hippocampus. Administration of the antidepressant fluoxetine had no significant effects on the increased depression-like behaviors, enriched cellular senescence, and aberrantly upregulated hippocampal ?-H2AX activity in Wip1 KO mice. After wildtype C57BL/6 mice were exposed to the procedure of chronic unpredictable mild stress (CUMS), cellular senescence and ?-H2AX activity in hippocampus were also elevated, accompanied by the suppression of Wip1 expression in hippocampus when compared to the control group without CUMS experience. These CUMS-induced symptoms were effectively prevented following fluoxetine administration in wildtype C57BL/6 mice, with the normalization of depression-like behaviors. Our data demonstrate that Wip1-mediated ?-H2AX dephosphorylation may play an important role in the occurrence of depression-related cellular senescence.
Project description:BACKGROUND: Although the accumulation of homocysteine (Hcy) has been implicated in the pathogenesis of depression, whether Hcy is directly involved and acts as the primary cause of depressive symptoms remains unclear. The present study was designed to clarify whether increased Hcy plays an important role in stress-induced depression. RESULTS: We employed the chronic unpredictable mild stress model (CUMS) of depression for 8 weeks to observe changes in the plasma Hcy level in the development of depression. The results showed that Wistar rats exposed to a series of mild, unpredictable stressors for 4 weeks displayed depression-like symptoms such as anhedonia (decreased sucrose preferences) and a decreased 5-Hydroxy Tryptophan (5-HT) concentration in the hippocampus. At the end of 8 weeks, the plasma Hcy level increased in the CUMS rats. The anti-depressant sertraline could decrease the plasma Hcy level and improve the depression-like symptoms in the CUMS rats. RhBHMT, an Hcy metabolic enzyme, could decrease the plasma Hcy level significantly, although it could not improve the depressive symptoms in the CUMS rats. CONCLUSIONS: The results obtained from the experiments did not support the hypothesis that the increased Hcy concentration mediated the provocation of depression in CUMS rats, and the findings suggested that the increased Hcy concentration in the plasma might be the result of stress-induced depression.
Project description:In the clinic selective serotonin reuptake inhibitors (SSRIs), like Fluoxetine, remain the primary treatment for major depression. It has been suggested that miR-16 regulates serotonin transporters (SERT) via raphe nuclei and hippocampal responses to antidepressants. However, the underlying mechanism and regulatory pathways are still obtuse. Here, a chronic unpredicted mild stress (CUMS) depression model in rats was established, and then raphe nuclei miR-16 and intragastric Fluoxetine injections were administered for a duration of 3 weeks. An open field test and sucrose preference quantification displayed a significant decrease in the CUMS groups when compare to the control groups, however these changes were attenuated by both miR-16 and Fluoxetine treatments. A dual-luciferase reporter assay system verified that hsa-miR-16 inhibitory effects involve the targeting of 3'UTR on the 5-HTT gene. Expression levels of miR-16 and BDNF in the hippocampus were examined with RT-PCR, and it was found that increased 5-HT2a receptor expression induced by CUMS can be decreased by miR-16 and Fluoxetine administration. Immunofluorescence showed that expression levels of neuron NeuN and MAP-2 in CUMS rats were lower. Apoptosis and autophagy levels were evaluated separately through relative expression of Bcl-2, Caspase-3, Beclin-1, and LC3II. Furthermore, CUMS was found to decrease levels of hippocampal mTOR, PI3K, and AKT. These findings indicate that apoptosis and autophagy related pathways could be involved in the effectiveness of antidepressants, in which miR-16 participates in the regulation of, and is likely to help integrate rapid therapeutic strategies to alleviate depression clinically. These findings indicate that miR-16 participates in the regulation of apoptosis and autophagy and could account for some part of the therapeutic effect of SSRIs. This discovery has the potential to further the understanding of SSRIs and accelerate the development of new treatments for depression.
Project description:Background:Chronic stress has been known to impair the female reproductive function, but the mechanism remains to be further investigated. Chaiyu-Dixian Formula (CYDXF) has been reported to regulate human endocrine disorders clinically. However, whether this formula can affect chronic stress-induced ovarian follicular development is not clear. Aim of the study:To examine effects of CYDXF on follicular development and explore possible mech anisms in a chronic unpredictable mild stress (CUMS) model. Materials and Methods:Adult female rats were randomly divided into 5 groups control group, CUMS group (saline treatment), CUMS+Estradiol (E2) (0.1 mg/kg) group, CUMS+CYDXF (2.73 g/kg) group, and CUMS+CYDXF (5.46 g/kg) group. Body weights and behavioral tests were documented. Serum hormone levels were determined by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the protein levels in the PI3K/Akt pathway and brain-derived neurotrophic factor (BDNF). The follicles were analyzed and classified according to their morphological characterization. Results:CYDXF relieved depression-like behaviors and ameliorated the abnormality in rat estrous cycle within the rat model of CUMS. Moreover, CYDXF could regulate endocrine disorders, increase the proportion of antral follicles as well as decrease the proportion of follicular atresia, which suggested that CYDXF could alleviate abnormal follicular development and improve overall ovarian function. Furthermore, CYDXF also activated the BDNF-mediated PI3K/Akt signaling pathway. Conclusions:CYDXF (at dose of both 2.73 and 5.46 g/kg) attenuated chronic stress-induced abnormal ovarian follicular development by relieving depression-like behaviors and improving ovarian function through partly the regulation of the BDNF-mediated PI3K/Akt pathway.
Project description:The present study hypothesized that caffeic acid (3,4?dihydroxycinnamic acid; CaA) may exert antidepressant?like effects in rats with chronic unpredictable mild stress via epigenetic mechanisms, such as DNA methylation and hydroxymethylation. The chronic unpredictable mild stress (CUMS) model was used to analyze the effects of CaA on behavioral phenotypes, and to evaluate the distribution of 5?methylcytosine (5mC) and 5?hydroxymethylcytosine (5hmC) in the hippocampus and prefrontal cortex using immunohistochemistry and immunofluorescence. mRNA levels of the genes encoding brain?derived neurotropic factor (BDNF) and catechol?O?methyltransferase (COMT), and key enzymes regulating DNA methylation [DNA methyltransferase (DNMT)1 and DNMT3A] and hydroxymethylation [Ten?eleven translocation (TET)1?3] were examined using quantitative (q)PCR. Furthermore, enrichment of 5mC and 5hmC at the promotor regions of the Bdnf and Comt genes was quantified using chromatin immunoprecipitation?qPCR. Behavioral data showed that CaA exerted a slight antidepressant?like effect. Bdnf and Comt genes showed differential expression patterns due to CUMS. CaA intervention induced different Dnmt1/Dnmt3a and Tet1/Tet2 mRNA levels in the hippocampus and prefrontal cortex, respectively. CaA regulated the ratio of 5mC/5hmC at the promotor region of the Bdnf and Comt genes and therefore influenced gene expression, which may be a valuable therapeutic option for major depressive disorder (MDD). In conclusion, there were epigenetic changes in the hippocampus and prefrontal cortex in CUMS rats, and CaA may function as a modulator of DNA methylation to regulate gene transcription, thus providing a mechanistic basis for the use of this phytochemical agent in the treatment of MDD.
Project description:Leptin plays a key role in the pathogenesis of obesity and depression via the long form of leptin receptor (LepRb). An animal model of comorbid obesity and depression induced by high-fat diet (HFD) combined with chronic unpredictable mild stress (CUMS) was developed to study the relationship between depression/anxiety-like behavior, levels of plasma leptin and LepRb in the brains between four groups of rats, the combined obesity and CUMS (Co) group, the obese (Ob) group, the CUMS group and controls. Our results revealed that the Co group exhibited most severe depression-like behavior in the open field test (OFT), anxiety-like behavior in elevated plus maze test (EMT) and cognitive impairment in the Morris water maze (MWM). The Ob group had the highest weight and plasma leptin levels while the Co group had the lowest levels of protein of LepRb in the hypothalamus and hippocampus. Furthermore, depressive and anxiety-like behaviors as well as cognitive impairment were positively correlated with levels of LepRb protein and mRNA in the hippocampus and hypothalamus. The down-regulation of leptin/LepRb signaling might be associated with depressive-like behavior and cognitive impairment in obese rats facing chronic mild stress.