Neuroanatomical, Biochemical, and Functional Modifications in Brain Induced by Treatment with Antidepressants

Impact of Larval Sertraline Exposure on Alternative Splicing in Neural Tissue of Adult Drosophila melanogaster

Sertraline, a selective serotonin reuptake inhibitor (SSRI), is commonly used to treat various psychiatric disorders such as depression and anxiety due to its ability to increase serotonin availability in the brain. Recent findings suggest that sertraline may also influence the expression of genes related to synaptic plasticity and neuronal signaling pathways. Alternative splicing, a process that allows a single gene to produce multiple protein isoforms, plays a crucial role in the regulation of neuronal functions and plasticity. Dysregulation of alternative splicing events has been linked to various neurodevelopmental and neurodegenerative diseases. This study aims to explore the effects of sertraline on alternative splicing events, including exon inclusion, exon exclusion, and mutually exclusive splicing events, in genes associated with neuronal function in Drosophila melanogaster and to use this model to investigate the molecular impacts of SSRIs on gene regulation in the nervous system. RNA sequencing (RNA-seq) was performed on central nervous system samples from Drosophila melanogaster adults exposed to sertraline for 24 h when they were third instar larvae. Alternative splicing events were analyzed to identify changes in exon inclusion and exclusion, as well as intron retention. Sertraline treatment significantly altered alternative splicing patterns in key genes related to neuronal stability and function. Specifically, sertraline promoted the inclusion of long Ank2 isoforms, suggesting enhanced axonal stability, and favored long ATPalpha isoforms, which support Na+/K+ ATPase activity essential for ionic balance and neuronal excitability. Intron retention in the yuri gene suggests that cytoskeletal reorganization could impact neuronal morphology. Additionally, splicing alterations in sxc and Atg18a indicate a potential influence of sertraline on epigenetic regulation and autophagy processes, fundamental aspects for neuronal plasticity and cellular homeostasis. These findings suggest that sertraline influences alternative splicing in the central nervous system of Drosophila melanogaster, potentially contributing to its therapeutic effects by modulating neuronal stability and adaptability.

Drug-induced Parkinson-like events: a real-world study from 2004 to the first quarter of 2024 based on FAERS

Background

Timely identification of drug-induced Parkinson-like events is essential to improve clinical management and enhance patients' quality of life. However, there is a significant lack of studies addressing these events in real-world settings.

Methods

To bridge this gap, we analyzed adverse event (AE) reports related to Parkinson-like events from the FDA Adverse Event Reporting System (FAERS) database from the first quarter of 2004 to the first quarter of 2024. Our objective was to summarize a list of potential drugs at high risk for Parkinson-like events and their corresponding proportions of AE reports.

Results

As a result, a total of 54,639 AE reports linked to Parkinson-like events involving 1,224 drugs were identified. Among these, carbidopa/levodopa exhibited the highest number of reports, followed by baclofen and pimavanserin. The most frequently reported drug class was antiparkinsonian drugs and psycholeptics, followed by psychoanaleptics. Using two disproportionate analysis methods, the reporting odds ratio and proportional reporting ratio, we found that 136 drugs exhibited positive results in both methods, while 1,063 drugs did not show any positive signals.

Conclusion

This study provides a comprehensive pharmacovigilance analysis of drugs associated with Parkinson-like events, aiming to promote rational drug use and inform clinical practice.

SEP-363856 attenuates CUMS-induced depression-like behaviours and reverses hippocampal neuronal injuries

OBJECTIVES

This study employed a chronic unpredictable mild stress (CUMS) model to examine the antidepressant properties of SEP-363856.

METHODS

The sucrose preference test (SPT) was employed to evaluate anhedonia, the open field test (OFT) to measure locomotor activity and exploratory behaviour, the elevated plus-maze (EPM) to assess anxiety-like behaviour, and the tail suspension test (TST) and forced swimming test (FST) to determine despair behaviour. qRT-PCR was implemented to evaluate gene expression levels in the hippocampus. Western blot, and ELISA were implemented to evaluate hippocampal protein expression, and Nissl staining was implemented to identify hippocampal neuronal injury.

RESULTS

The 10 mg/kg dosage of SEP-363856 and fluoxetine significantly improved depressive-like behaviours as assessed by the SPT, OFT, EPM, TST, and FST. This was associated with improved hippocampal neuronal damage, enhanced mRNA expression of brain-derived neurotrophic factor, synaptophysin, and postsynaptic density 95. SEP-363856 increased the levels of insulin-like growth factor-1 (IGF-1), IGF-1 receptor β, phospho-phosphatidylinositide 3-kinase, and phospho-protein kinase B in the brain.

CONCLUSIONS

The antidepressant-like effects of SEP-363856 are linked to increased hippocampal neurotrophic factors, decreased hippocampus neuronal lesions, and activation of the IGF-1Rβ/PI3K/AKT signalling pathway. The latter may serve as a novel drug target for the treatment of depression.

Simultaneous use of venlafaxine and calcium channel blockers on tolerance to morphine: The role of mitochondrial damage and oxidative stress in the brain

BACKGROUND

One of the reasons for tolerance to morphine is increased oxidative stress and dysfunction of cell mitochondria in the hippocampus. Venlafaxine and calcium channel blockers can protect mitochondrial function. The investigation of the role of mitochondrial damage and oxidative stress in the simultaneous use of venlafaxine and calcium channel blockers on the acute analgesic effects of morphine and the induction of tolerance to its effects in mice was assessed.

METHOD

In this experimental study, to induce tolerance to morphine, NMRI mice were treated with 50 mg/kg morphine for three consecutive days and 5 mg/kg morphine on the fourth day. Venlafaxine (20 mg/kg) alone or in combination with calcium channel blockers, nimodipine (10 mg/kg), and diltiazem (40 mg/kg) was administered 30 min before morphine, and the hot plate test was used. Then, hippocampal mitochondria were isolated by differential centrifugation method, and the levels of mitochondrial dehydrogenase activity, mitochondrial membrane potential, mitochondrial ROS production rate, as well as the content of glutathione and malondialdehyde in hippocampal mitochondria, were measured.

RESULTS

The administration of venlafaxine-nimodipine and venlafaxine-diltiazem increased morphine's acute analgesic effects (P < 0.05) and reduced the induction and expression of tolerance to the analgesic effects of morphine (P < 0.05). Morphine significantly decreased MTT and GSH and increased MDA, mitochondrial membrane damage, and ROS compared to the control group (P < 0.01). Injection of venlafaxine-nimodipine and also venlafaxine-diltiazem 30 min before morphine can improve these alterations (P < 0.05).

DISCUSSION AND CONCLUSION

Our data showed that the simultaneous use of venlafaxine with calcium channel blockers could increase the acute analgesic effects of morphine and reduce the induction and expression of tolerance to it. Also, the preventive and protective roles of simultaneous administration of venlafaxine and calcium channel blockers on morphine-induced mitochondrial oxidative stress and damage during the tolerance test were achieved.

Reproductive Toxicity Induced by Serotonin-Norepinephrine Reuptake Inhibitors: A Pharmacovigilance Analysis From 2004 to 2023 Based on the FAERS Database

AIM

Serotonin-norepinephrine reuptake inhibitors (SNRIs) have been extensively utilized for the treatment of depression and anxiety disorders. Clinical trials and real-world data suggest that SNRIs may cause reproductive toxicity. To comprehensively assess this association, we conducted a pharmacovigilance study.

METHODS

We utilized various disproportionality analysis algorithms, including reporting odds ratio (ROR), proportional reporting ratio (PRR), bayesian confidence propagation neural network (BCPNN), and multi-item gamma poisson shrinker (MGPS), to assess the significance of reproductive toxicity-related adverse events (AEs) reported to FDA Adverse Event Reporting System (FAERS) from January 2004 to December 2023, with subgroup analysis conducted by sex and age.

RESULTS

Duloxetine and venlafaxine were associated with 14 and 25 AE signals related to reproductive toxicity, respectively, with erectile dysfunction (ED) and retrograde ejaculation identified as shared important medical events (IMEs). ED had the highest reporting frequency, strongest in venlafaxine-treated patients under 45 years (ROR 4.34, PRR 4.33, IC 2.09, EBGM 4.25). Retrograde ejaculation was newly identified. With decreasing incidence, venlafaxine's median ED onset was 122.5 days and duloxetine's 38 days.

CONCLUSION

Our study provides evidence through an extensive analysis of the large-scale real-world FAERS database, aiding healthcare professionals in mitigating, and prioritizing SNRI-related reproductive toxicity AEs.

Paeoniflorin Inhibits the Activation of Microglia and Alleviates Depressive Behavior by Regulating SIRT1-NF-kB-NLRP3/Pyroptosis Pathway

Inflammation assumes a vital role in the pathogenesis of depression and in antidepressant treatment. Paeoniflorin (PF), a monoterpene glycoside analog possessing anti-inflammatory attributes, exhibits therapeutic efficacy on depression-like behavior in mice. The objective of this study was to evaluate the antidepressant effects of PF on depression elicited by the chronic unpredictable mild stress (CUMS) model and the precise neural sequence associated with the inflammatory process. In this study, we established an in vivo mouse model induced by CUMS and an in vitro BV2 cell model induced by LPS+ATP. The mechanism of PF for depression was assessed by the SIRT1 selective inhibitor EX-527. The findings demonstrated that PF significantly alleviated the damage of BV2 cells treated with LPS and ATP, inhibited the generation of ROS, up-regulated the expression of SIRT1 mRNA, and down-regulated the expression of nuclear NF-κB, p65, NLRP3, Caspase-1 and GSDMD-N in vitro. In vivo, PF mitigated the depressive-like behavior induced by CUMS, reduced the number of neurons, and decreased the secretion of pro-inflammatory factors IL-1β, IL-6, and TNF-α in the hippocampus. Immunohistochemical results indicated that PF attenuated CUMS-induced hyperactivation of microglia. Moreover, the expression level of SIRT1 in the hippocampus was augmented, while the protein levels of NF-κB, p65, NLRP3, Caspase-1, IL-1β and GSDMD-N were diminished after PF treatment. Additionally, the selective inhibition of SIRT1 attenuated the therapeutic effect of PF on depression. These results imply that PF possesses antidepressant properties that rely on SIRT1 signaling to regulate NLRP3 inflammasome inactivation.

Resolving a paradox: antidepressants, neuroinflammation, and neurodegeneration

Depression is a known risk factor for dementia. Antidepressants are the most commonly used treatment for this condition, and are effective in at least half to two-thirds of cases. Extensive evidence from in vitro and animal models suggests that antidepressants have anti-inflammatory and neuroprotective properties. These effects have been shown to reduce the oxidative damage, amyloid aggregation, and expression of pro-inflammatory genes associated with animal models of neurodegenerative disorders. However, longitudinal research in humans has shown that antidepressants do not protect against dementia, and may even be associated with a risk of cognitive deterioration over time in older adults. The contrast between two sets of findings represents a paradox of significant clinical and public health significance, particularly when treating depression in late life. This review paper attempts to resolve this paradox by critically reviewing the medium- and long-term effects of antidepressants on peripheral immune-inflammatory responses, infection risk, gut microbiota, and neuroendocrine responses to stress, and how these effects may influence the risk of neurodegeneration. Briefly stated, it is possible that the peripheral actions of antidepressant medications may antagonize their beneficial effects against neuroinflammation. The implications of these findings are then explored with a particular focus on the development and testing of multimodal neuroprotective and anti-inflammatory treatments that could reduce the risk of Alzheimer’s and related dementias in patients suffering from depression.

Research progress on classical traditional chinese medicine formula xiaoyaosan in the treatment of depression

Depression is an emotional disorder that is problematic in psychiatry owing to its unclear etiology and unknown pathogenesis. Traditional Chinese medicine formulations such as Xiaoyaosan have been widely used throughout history to treat depression. In this review, we have focused on recent evidences elucidating the links between Xiaoyaosan and the treatment of depression. Data from animal and clinical studies, focusing on the pharmacological mechanisms, clinical applications, and effective materials that form the basis for the treatment of depression are presented and discussed. We found that the antidepressant effects of Xiaoyaosan are related to the effects of monoamine neurotransmitters, regulation of the hypothalamic-pituitary-adrenal axis, neuroplasticity, synaptic plasticity, inflammatory response, neuroprotection, brain-gut axis, regulation of intestinal microbiota, oxidative stress, and autophagy for reducing neuronal apoptosis. This review highlights the current evidence supporting the use of Xiaoyaosan as an antidepressant and provides an overview of the potential mechanisms involved.

Baicalein Exerts Therapeutic Effects against Endotoxin-Induced Depression-like Behavior in Mice by Decreasing Inflammatory Cytokines and Increasing Brain-Derived Neurotrophic Factor Levels

Inflammation plays an important role in the pathophysiology of depression. This study aims to elucidate the antidepressant effect of baicalein, an anti-inflammatory component of a traditional Chinese herbal medicine (Scutellaria baicalensis), on lipopolysaccharide (LPS)-induced depression-like behavior in mice, and to investigate the underlying mechanisms. In vitro, baicalein exhibited antioxidant activity and protected macrophages from LPS-induced damage. The results of the tail suspension test and forced swimming test (tests for despair potential in mice) showed the antidepressant effect of baicalein on LPS-treated mice. It also substantially decreased the production of pro-inflammatory cytokines, including IL-6, TNF-α, MCP-1, and eotaxin, elicited by LPS in the plasma. Baicalein downregulated NF-κB-p65 and iNOS protein levels in the hippocampus, demonstrated its ability to mitigate neuroinflammation. Additionally, baicalein increased the levels of the mature brain-derived neurotrophic factor (mBDNF) in the hippocampus of LPS-treated mice, and elevated the ratio of mBDNF/proBDNF, which regulates neuronal survival and synaptic plasticity. Baicalein also promoted the expression of CREB, which plays a role in a variety of signaling pathways. In summary, the findings of this study demonstrate that the administration of baicalein can attenuate LPS-induced depression-like behavior by suppressing neuroinflammation and inflammation induced by the peripheral immune response.