Venlafaxine increases cell proliferation and regulates DISC1, PDE4B and NMDA receptor 2B expression in the hippocampus in chronic mild stress mice

Hippocampal SENP3 mediates chronic stress-induced depression-like behaviors by impairing the CREB-BDNF signaling

Impaired signaling between cyclic adenosine monophosphate response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus is generally considered to be the cause of depression. The mechanisms underlying the impairment of CREB-BDNF signaling under stress conditions are largely unclear. Small ubiquitin-like modifier (SUMO) specific peptidase 3 (SENP3) is a molecule that can regulate SUMOylation of target proteins related to synaptic plasticity. Its dynamic changes have been reported to be associated with neuronal damage in various models of central nervous disorders such as cerebral ischemia and traumatic brain injury. However, its role in depression is completely unknown. This problem was addressed in the present study. Our results showed that chronic unpredictable stress (CUS) triggered a specific increase in SENP3 expression in the hippocampus of non-stressed mice. Overexpression of SENP3 in the hippocampus of non-stressed mice elicited depression-like behaviors in the tail suspension test, forced swimming test, and sucrose preference test, accompanied by impairment of the CREB-BDNF signaling cascade in the hippocampus. Conversely, genetic silencing of SENP3 in the hippocampus suppressed the development of depression-like behaviors. Furthermore, infusion of SENP3-shRNA into the hippocampus failed to suppress CUS-induced depression-like behaviors when mice received genetic silencing CREB or BDNF in the hippocampus or inhibition of the BDNF receptor by K252a. Taken together, these results suggest that abnormally elevated SENP3 in the hippocampus leads to the development of depression-like behavior by impairing the CREB-BDNF signaling cascade. SENP3 in the hippocampus could be a promising target for the development of new antidepressants.

BMAL1-Potential Player of Aberrant Stress Response in Q31L Mice Model of Affective Disorders: Pilot Results

Dysregulation in the stress-response system as a result of genetical mutation can provoke the manifestation of affective disorders under stress conditions. Mutations in the human DISC1 gene is one of the main risk factors of affective disorders. It was known that DISC1 regulates a large number of proteins including BMAL1, which is involved in the regulation of glucocorticoid synthesis in the adrenal glands and the sensitivity of glucocorticoid receptor target genes. Male mice with a point mutation Q31L in the Disc1 gene were exposed to chronic unpredictable stress (CUS), after which the behavioral and physiological stress response assessed. To assess whether there were any changes in BMAL1 in key brain regions involved in the stress response, immunohistochemistry was applied. It was shown that the Q31L mice had an aberrant behavioral response, especially to the 2 weeks of CUS, which was expressed in unchanged motor activity, increased time of social interaction, and alterations in anxiety and fear-related behavior. Q31L males did not show an increase in blood corticosterone levels after CUS and a decrease in body weight. Immunohistochemical analysis in intact Q31L mice revealed a decrease in BMAL1 immunofluorescence in the CA1 hippocampal area and lateral habenula. Thus, the Q31L mutation of the Disc1 gene disrupts behavioral and physiological stress response and the BMAL1 dysregulation may underlie it, so this protein can act as a molecular target for the treatment of affective disorders.

The Mechanisms Underlying the Pharmacological Effects of GuiPi Decoction on Major Depressive Disorder based on Network Pharmacology and Molecular Docking

BACKGROUND AND AIM

Major Depressive Disorder (MDD) is a common affective disorder. GuiPi decoction (GPD) is used to treat depression in China, Japan, and Korea. However, its effective ingredients and antidepressant mechanisms remain unclear. We attempted to reveal the potential mechanisms of GPD in the treatment of MDD by network pharmacology and molecular docking. In addition, we conducted an enzymatic activity assay to validate the results of molecular docking.

METHODS

GPD-related compounds and targets, and MDD-related targets were retrieved from databases and literature. The herb-compound-target network was constructed by Cytoscape. The protein- protein interaction network was built using the STRING database to find key targets of GPD on MDD. Enrichment analysis of shared targets was analyzed by MetaCore database to obtain the potential pathway and biological process of GPD on MDD. The main active compounds treating MDD were screened by molecular docking. The PDE4s inhibitors were screened and verified by an enzyme activity assay.

RESULTS

GPD contained 1222 ingredients and 190 potential targets for anti-MDD. Possible biological processes regulated by GPD were neurophysiological processes, blood vessel morphogenesis, Camp Responsive Element Modulator (CREM) pathway, and Androgen Receptor (AR) signaling crosstalk in MDD. Potential pathways in MDD associated with GPD include neurotransmission, cell differentiation, androgen signaling, and estrogen signaling. Fumarine, m-cresol, quercetin, betasitosterol, fumarine, taraxasterol, and lupeol in GPD may be the targets of SLC6A4, monoamine oxidase A (MAOA), DRD2, OPRM1, HTR3A, Albumin (ALB), and NTRK1, respectively. The IC50 values of trifolin targeting Phosphodiesterase (PDE) 4A and girinimbine targeting PDE4B1 were 73.79 μM and 31.86 μM, respectively. The IC50 values of girinimbine and benzo[a]carbazole on PDE4B2 were 51.62 μM and 94.61 μM, respectively.

CONCLUSION

Different compounds in GPD may target the same protein, and the same component in GPD can target multiple targets. These results suggest that the effects of GPD on MDD are holistic and systematic, unlike the pattern of one drug-one target.

Psychopharmacological properties and therapeutic profile of the antidepressant venlafaxine

Major depression (MD) is one of the most common psychiatric disorders worldwide. Currently, the first-line treatment for MD targets the serotonin system but these drugs, notably the selective serotonin reuptake inhibitors, usually need 4 to 6 weeks before the benefit is felt and a significant proportion of patients shows an unsatisfactory response. Numerous treatments have been developed to circumvent these issues as venlafaxine, a mixed serotonin-norepinephrine reuptake inhibitor that binds and blocks both the SERT and NET transporters. Despite this pharmacological profile, it is difficult to have a valuable insight into its ability to produce more robust efficacy than single-acting agents. In this review, we provide an in-depth characterization of the pharmacological properties of venlafaxine from in vitro data to preclinical and clinical efficacy in depressed patients and animal models of depression to propose an indirect comparison with the most common antidepressants. Preclinical studies show that the antidepressant effect of venlafaxine is often associated with an enhancement of serotonergic neurotransmission at low doses. High doses of venlafaxine, which elicit a concomitant increase in 5-HT and NE tone, is associated with changes in different forms of plasticity in discrete brain areas. In particular, the hippocampus appears to play a crucial role in venlafaxine-mediated antidepressant effects notably by regulating processes such as adult hippocampal neurogenesis or the excitatory/inhibitory balance. Overall, depending on the dose used, venlafaxine shows a high efficacy on depressive-like symptoms in relevant animal models but to the same extent as common antidepressants. However, these data are counterbalanced by a lower tolerance. In conclusion, venlafaxine appears to be one of the most effective treatments for treatment of major depression. Still, direct comparative studies are warranted to provide definitive conclusions about its superiority.

HINT1 Is Involved in the Chronic Mild Stress Elicited Oxidative Stress and Apoptosis Through the PKC ε/ALDH-2/4HNE Pathway in Prefrontal Cortex of Rats

Major depressive disorder (MDD) is a severe, highly heterogeneous, and life-threatening psychiatric disease which affects up to 21% of the population worldwide. A new hypothesis suggests that the mitochondrial dysfunction causing oxidative stress (OS) and dysregulation of apoptosis in brain might be one of the key pathophysiological factors in MDD. Histidine triad nucleotide binding protein 1 (HINT1), which was first supposed to be protein kinase C (PKC) inhibitor, has been gradually demonstrated to be involved in diverse neuropsychiatric diseases. It still remains elusive that how HINT1 involves in depression. The present study utilized a rat model exposed to chronic mild stress (CMS) to explore the involvement of HINT1 in depression. Face validity, construct validity and predictive validity of CMS model were comprehensive evaluated in this study. Behavioral tests including sucrose preference test, open field test, and elevated plus maze and forced swimming test revealed that stressed rats displayed elevated level of anxiety and depression compared with the controls. CMS rats showed a significant decrease of superoxide dismutase, and a marked increase malondialdehyde levels in prefrontal cortex (PFC). We also found the CMS rats had elevated expression of HINT1, decreased levels of phosphorylated-PKC ε and aldehyde dehydrogenase-two (ALDH-2), and accumulated 4-hydroxynonenal (4HNE) in PFC. Moreover, CMS increased the levels of cleaved caspase-3 and Bax, and decreased the level of Bcl-2 in PFC. The alterations in behavior and molecule were prevented by antidepressant venlafaxine. These results demonstrated that HINT1 was involved in the CMS elicited OS and apoptosis in PFC, probably through the PKC ε/ALDH-2/4HNE pathway. The results suggest that the suppression of HINT1 might have potential as a novel therapeutic strategy for depression.

Venlafaxine protects against chronic stress-related behaviors in mice by activating the mTORC1 signaling cascade

BACKGROUND

Recent studies have suggested the role of mammalian target of rapamycin complex 1 (mTORC1) in the pathophysiology of depression. Although venlafaxine was thought to be a serotonin and norepinephrine reuptake inhibitor (SNRI), its pharmacological mechanism remain elusive. In this study, the effects of venlafaxine on the mTORC1 system were studied in both chronic unpredictable mild stress (CUMS) and chronic social defeat stress (CSDS) models.

METHOD

First, we examined whether repeated venlafaxine treatment reversed the effects of CUMS and CSDS on the mTORC1 signaling cascade in both the hippocampus and medial prefrontal cortex (mPFC). Second, several selective pharmacological inhibitors of the mTORC1 system, including rapamycin, LY294002 and U0126, were used together to determine whether the protective effects of venlafaxine against the CUMS and CSDS models were prevented by mTORC1 system blockade. Finally, genetic knockdown of mTORC1 by mTORC1-shRNA was further adopted to test whether mTORC1 was necessary for the anti-stress effects of venlafaxine in mice.

RESULT

Our results showed that the decreasing effects of CUMS and CSDS on the mTORC1 signaling cascade in the hippocampus and mPFC were restored by venlafaxine, and the use of rapamycin, LY294002, U0126 and mTORC1-shRNA fully abolished the anti-stress actions of venlafaxine in mice.

CONCLUSION

The mTORC1 system is involved in the pharmacological mechanism of venlafaxine.

The tricyclic antidepressant clomipramine inhibits neuronal autophagic flux

Antidepressants are commonly prescribed psychotropic substances for the symptomatic treatment of mood disorders. Their primary mechanism of action is the modulation of neurotransmission and the consequent accumulation of monoamines, such as serotonin and noradrenaline. However, antidepressants have additional molecular targets that, through multiple signaling cascades, may ultimately alter essential cellular processes. In this regard, it was previously demonstrated that clomipramine, a widely used FDA-approved tricyclic antidepressant, interferes with the autophagic flux and severely compromises the viability of tumorigenic cells upon cytotoxic stress. Consistent with this line of evidence, we report here that clomipramine undermines autophagosome formation and cargo degradation in primary dissociated neurons. A similar pattern was observed in the frontal cortex and liver of treated mice, as well as in the nematode Caenorhabditis elegans exposed to clomipramine. Together, our findings indicate that clomipramine may negatively regulate the autophagic flux in various tissues, with potential metabolic and functional implications for the homeostatic maintenance of differentiated cells.

JSH-23 prevents depressive-like behaviors in mice subjected to chronic mild stress: Effects on inflammation and antioxidant defense in the hippocampus

Nuclear factor-kappa B (NF-κB), which is reported to play an important role in the pathogenesis of depression, also has a central role in the genesis and progression of inflammation. Here, we have targeted the nuclear translocation of NF-κB using 4-methyl-N1-(3-phenyl-propyl)-benzene-1,2-diamine (JSH-23) to elucidate its role in depression. We investigated the antidepressant-like effects of JSH-23 in the chronic mild stress (CMS) mouse model, which is a valid, reasonably reliable, and useful model of depression. The antidepressant-like effects of JSH-23 were evaluated using the sucrose preference test (SPT) and the forced swimming test (FST). We also assessed inflammatory markers [interleukin (IL)-6 and tumor necrosis factor-α (TNF-α)] and components of antioxidant defense [superoxide dismutase (SOD) and nuclear factor erythroid-2-related factor 2 (Nrf 2)] in the hippocampus. Fluoxetine, a classical antidepressant, was used in this study as a positive control. Administration of JSH-23 significantly prevented the decreased sucrose preference in the SPT and prevented the increased immobility time in the FST caused by CMS, but had no effect on locomotor activity. Expression of NF-κB p65 protein in the hippocampus was decreased, and elevated levels of IL-6 and TNF-α were reduced, after JSH-23 administration. In addition to its anti-inflammatory effect, JSH-23 treatment increased the expression of SOD and Nrf 2 in the hippocampus, suggesting that it strengthens antioxidant defense. The current study demonstrated that inhibiting the NF-κB signaling cascade using JSH-23 prevented depressive-like behaviors by decreasing inflammation and improving antioxidant defense in the hippocampus. We concluded that NF-κB activation plays an important role in the pathophysiology of depression and that targeting NF-κB signaling may provide a novel and effective therapy for depression. Additional preclinical studies and clinical trials are, however, needed to further elucidate the effects of this therapeutic strategy.

Disrupted in schizophrenia 1 (DISC1) inhibits glioblastoma development by regulating mitochondria dynamics

Glioblastoma(GBM) is one of the most common and aggressive malignant primary tumors of the central nervous system and mitochondria have been proposed to participate in GBM tumorigenesis. Previous studies have identified a potential role of Disrupted in Schizophrenia 1 (DISC1), a multi-compartmentalized protein, in mitochondria. But whether DISC1 could regulate GBM tumorigenesis via mitochondria is still unknown. We determined the expression level of DISC1 by both bioinformatics analysis and tissue analysis, and found that DISC1 was highly expressed in GBM. Knocking down of DISC1 by shRNA in GBM cells significantly inhibited cell proliferation both in vitro and in vivo. In addition, down-regulation of DISC1 decreased cell migration and invasion of GBM and self renewal capacity of glioblastoma stem-like cells. Furthermore, multiple independent rings or spheres could be observed in mitochondria in GBM depleted of DISC1, while normal filamentous morphology was observed in control cells, demonstrating that DISC1 affected the mitochondrial dynamic. Dynamin-related protein 1 (Drp1) was reported to contribute to mitochondrial dynamic regulation and influence glioma cells proliferation and invasion by RHOA/ ROCK1 pathway. Our data showed a significant decrease of Drp1 both in mRNA and protein level in GBM lack of DISC1, indicating that DISC1 maybe affect the mitochondrial dynamic by regulating Drp1. Taken together, our findings reveal that DISC1 affects glioblastoma cell development via mitochondria dynamics partly by down regulation of Drp1.

Ficus sycomorus extract reversed behavioral impairment and brain oxidative stress induced by unpredictable chronic mild stress in rats

BACKGROUND

Stress, regardless of its nature is nowadays recognized as one of the major risk factors for neuropsychiatric diseases, such as mood and anxiety disorders. The brain compared with other organs is more vulnerable to oxidative damage mainly due to its high rate of oxygen consumption, abundant lipid content, and relative insufficiency of antioxidant enzymes. Thus, the identification of neural mechanisms underlying resistance and vulnerability to stress is of crucial importance in understanding the pathophysiology of neuropsychiatric disorders and in developing new treatments, since the existing ones are for several reasons subject to increasing limitations. This study was aimed to assess the effects of hydromethanolic extract of Ficus sycomorus stem bark on depression, anxiety and memory impairment induced by unpredictable chronic mild stress (UCMS) in rats.

METHODS

These effects were studied using anxiety-related behavior, depression-related behavior, anhedonia-like behavior and the Y maze task. Sucrose test was performed twice (before and after UCMS) to assess anhedonia in rats. Liquid chromatography-mass spectrometry analysis of the extract were performed. The antioxidant activities of the extract were assessed using total glutathione (GSH) content and malondialdehyde (MDA) level (lipid peroxidation) in the rat temporal lobe homogenates.

RESULTS

The extract of F. sycomorus in a dose of 100 mg/kg significantly increased the sucrose consumption and the swimming time which had been reduced by the unpredictable chronic mild stress (p < 0.001). The extract also significantly reduced (p < 0.01) the latency time in the novelty-suppressed feeding test. In the elevated plus-maze, the extract (100 and 200 mg/kg) significantly reduced (p < 0.01) the time and the number of entries into the closed arms. The treatment with the extracts also significantly increased alternation in the Y-maze (p < 0.01 for 100 mg/kg). The extract significantly increased the total GSH content and reduced MDA level in rat temporal lobe. For the LC-MS analysis, the major compound in the extract was a flavonoid with formula C22H28O14.

CONCLUSIONS

F. sycomorus reversed the harmful effects of UCMS on mood and behaviors in rats and it possesses an antidepressant property that is at least in part mediated through the oxidative pathway.

Rescue of IL-1β-induced reduction of human neurogenesis by omega-3 fatty acids and antidepressants

Both increased inflammation and reduced neurogenesis have been associated with the pathophysiology of major depression. We have previously described how interleukin-1 (IL-1) β, a pro-inflammatory cytokine increased in depressed patients, decreases neurogenesis in human hippocampal progenitor cells. Here, using the same human in vitro model, we show how omega-3 (ω-3) polyunsaturated fatty acids and conventional antidepressants reverse this reduction in neurogenesis, while differentially affecting the kynurenine pathway. We allowed neural cells to proliferate for 3days and further differentiate for 7days in the presence of IL-1β (10ng/ml) and either the selective serotonin reuptake inhibitor sertraline (1µM), the serotonin and norepinephrine reuptake inhibitor venlafaxine (1µM), or the ω-3 fatty acids eicosapentaenoic acid (EPA, 10µM) or docosahexaenoic acid (DHA, 10µM). Co-incubation with each of these compounds reversed the IL-1β-induced reduction in neurogenesis (DCX- and MAP2-positive neurons), indicative of a protective effect. Moreover, EPA and DHA also reversed the IL-1β-induced increase in kynurenine, as well as mRNA levels of indolamine-2,3-dioxygenase (IDO); while DHA and sertraline reverted the IL-1β-induced increase in quinolinic acid and mRNA levels of kynurenine 3-monooxygenase (KMO). Our results show common effects of monoaminergic antidepressants and ω-3 fatty acids on the reduction of neurogenesis caused by IL-1β, but acting through both common and different kynurenine pathway-related mechanisms. Further characterization of their individual properties will be of benefit towards improving a future personalized medicine approach.

Biochemical effects of venlafaxine on astrocytes as revealed by 1H NMR-based metabolic profiling

As a serotonin–norepinephrine reuptake inhibitor [SNRI], venlafaxine is one of the most commonly prescribed clinical antidepressants, with a broad range of antidepressant effects.

Differential effect of clomipramine on habituation and prepulse inhibition in dominant versus subordinate rats

Many patients with depression have comorbidities associated with an impairment of sensorimotor gating, such as e.g. schizophrenia, Parkinson Disease, or Alzheimer disease. Anti-depressants like clomipramine that modulate serotonergic or norepinephrinergic neurotransmission have been shown to impact sensorimotor gating, it is therefore important to study potential effects of clomipramine in order to rule out an exacerbation of sensorimotor gating impairment. Prior studies in animals and humans have been inconclusive. Since serotonin and norepinephrine levels are closely related to anxiety and stress levels and therefore to the social status of an animal, we tested the hypothesis that acute and chronic effects of clomipramine on sensorimotor gating are different in dominant versus subordinate rats, which might be responsible for conflicting results in past animal studies. We used habituation and prepulse inhibition (PPI) of the acoustic startle response as operational measures of sensorimotor gating. After establishing the dominant animal in pair-housed male rats, we injected clomipramine for two weeks and measured acute effects on baseline startle, habituation and PPI after the first injection and chronic effects at the end of the two weeks. Chronic treatment with clomipramine significantly increased habituation in subordinate rats, but had no effect on habituation in dominant animals. Furthermore, PPI was slightly enhanced in subordinate rats upon chronic treatment while no changes occurred in dominant animals. We conclude that the social status of an animal, and therefore the basic anxiety/stress level determines whether or not clomipramine has a beneficial effect on sensorimotor gating and discuss possible underlying mechanisms.

Quercitrin offers protection against brain injury in mice by inhibiting oxidative stress and inflammation

Quercitrin is one of the primary flavonoid compounds present in vegetables and fruits.

MEK Inhibitors Reverse cAMP-Mediated Anxiety in Zebrafish

Altered phosphodiesterase (PDE)-cyclic AMP (cAMP) activity is frequently associated with anxiety disorders, but current therapies act by reducing neuronal excitability rather than targeting PDE-cAMP-mediated signaling pathways. Here, we report the novel repositioning of anti-cancer MEK inhibitors as anxiolytics in a zebrafish model of anxiety-like behaviors. PDE inhibitors or activators of adenylate cyclase cause behaviors consistent with anxiety in larvae and adult zebrafish. Small-molecule screening identifies MEK inhibitors as potent suppressors of cAMP anxiety behaviors in both larvae and adult zebrafish, while causing no anxiolytic behavioral effects on their own. The mechanism underlying cAMP-induced anxiety is via crosstalk to activation of the RAS-MAPK signaling pathway. We propose that targeting crosstalk signaling pathways can be an effective strategy for mental health disorders, and advance the repositioning of MEK inhibitors as behavior stabilizers in the context of increased cAMP.