Mouse Model Of Depression Research Articles

Integrating Network Pharmacology and Transcriptomic Strategies to Explore the Pharmacological Mechanism of Paeoniflorin Exerts Antidepressant Effects

Background: Paeoniflorin has been proven to have neuroprotective and antidepressant effects in several studies. However, there is currently no comprehensive elaboration of its antidepressant effects through network pharmacology combined with transcriptomics analysis. The purpose of this study is to explore the potential mechanisms by which paeoniflorin exerts its antidepressant effects using network pharmacology and transcriptomics sequencing approaches. Methods: We utilized metascape to enrich the intersecting targets for paeoniflorin and depression for enrichment analyses. Additionally, we employed Cytoscape software to construct target pathway networks. For the screening of differentially expressed genes (DEGs) altered by paeoniflorin, we sequenced mRNA from the hippocampal tissue of CUMS model mice using the BMKCloud platform. We further enriched their biological functions and signaling pathways by using the Omishare database. The study utilized a combination of network pharmacology and transcriptomics analysis to evaluate the interactions between paeoniflorin and key targets. The results were then verified through a molecular docking process and a subsequent Western blot experiment. Results: According to a comprehensive analysis, paeoniflorin has 19 key targets that are closely related to its therapeutic effect. Molecular docking revealed that paeoniflorin has a high affinity for HIF-1α, VEGFA, and other targets. Furthermore, protein expression and immunofluorescence staining analysis showed that paeoniflorin significantly increased the expression level of HIF-1α and VEGFA in the hippocampus of depression model mice. Conclusion: These findings suggest that paeoniflorin may have therapeutic potential in depression through the activation of the HIF-1α-VEGFA pathway.

Dural Tregs driven by astrocytic IL-33 mitigate depression through the EGFR signals in mPFC neurons.

The dura sinus-resident immune cells can influence the process of central neural system (CNS) diseases by communicating with central nerve cells. In clinical, Tregs are also frequently impaired in depression. However, the significance of this relationship remains unknown. In the present study, we found a significant increase in dural Treg populations in mouse models of depression, whereas depleting them by neutralizing antibodies injection could exacerbate depressive phenotypes. Through RNA sequencing, we identified that the antidepressant effects of dural Tregs are at least in part through the production of amphiregulin, increasing the expression of its receptor EGFR in medial prefrontal cortex (mPFC) pyramidal neurons. Furthermore, dural Tregs expressed high levels of ST2, and their expansion in depressed mice depended on astrocyte-derived IL33 secretion. Our study shows that dural Treg signaling can be enhanced by treatment with fluoxetine, highlighting that dural Tregs can be utilized as a potential target cell in major depressive disorder (MDD).

Fructus Arctii Mitigates Depressive Disorder via the Let-7e-Modulated Toll-Like Receptor (TLR) Signaling Pathway.

Depressive disorder is a common and serious public health challenge globally. Fructus arctii is a traditional medicinal plant ingredient with diverse pharmacological effects. This study aimed to investigate the therapeutic potential of Fructus arctii in alleviating depressive-like behaviors. We established a chronic unpredictable mild stress (CUMS)-induced depression mouse model to assess the antidepressant effects of Fructus arctii. BV2 cells treated with lipopolysaccharide (LPS) were used to mimic neuronal damage. Behavioral tests, including the sucrose preference test, tail-suspension test, and forced swim test, were conducted to evaluate the impact of Fructus arctii on depressive-like behaviors. Let-7e expression was detected by RT-qPCR, and TLR4 signaling pathway activation was evaluated by western blot analysis, which also assessed the inflammatory response by measuring levels of IL-6, IL-1β, MCP-1, TNF-α, and iNOS. Immunohistological analysis was conducted to detect the expression of microglia markers. Luciferase reporter assays verified the interaction between let-7e and TLR4. Fructus arctii administration effectively alleviated depressive-like behaviors induced by CUMS in mice, as evidenced by improved sucrose preference and reduced immobility time in behavioral tests. Mechanistically, Fructus arctii reversed the CUMS-induced downregulation of let-7e and upregulation of TLR4 and MyD88 protein levels in mice hippocampus tissues. In addition, Fructus arctii suppressed microglial activation and reduced the levels of inflammatory factors by upregulating let-7e. Let-7e was verified to bind to TLR4, thereby negatively regulating its expression. TLR4 overexpression reversed the suppressive effect of let-7e upregulation on inflammatory reactions and microglial activation. Furthermore, intracerebroventricular injection of let-7e agomiR alleviated depressive-like behavior and inhibited microglial activation in vivo. In summary, Fructus arctii mitigates depression by regulating the let-7e/TLR4/MyD88 pathway, offering new insights into potential depression therapies.

Ginsenoside Rg1 enriches gut microbial indole-3-acetic acid to alleviate depression-like behavior in mice via oxytocin signaling

Background and purposeAlthough a large collection of data has shown that ginsenosides, the major active ingredients from Ginseng, have neuroprotective and anti-depressant effect, the mechanism of action is incompletely understood. This study aims to elucidate the antidepressant mechanism of ginsenoside Rg1 (Rg1), a poorly absorbed ginsenoside, from the perspective of gut microbe to brain signaling. MethodsA mouse model of depression was induced by unpredictable mild stress (UMS). Behavioral and neurochemical tests were conducted to evaluate the effect and mechanism of Rg1 on depressive behavior. Non-target and target metabolomics were performed to identify the signaling metabolites underlying the antidepressant efficacy of Rg1. Gut microbial structure was analyzed by 16S rRNA sequencing and the potential functional strains associated with Rg1 action were investigated by in vitro bacterial culture. Chemical intervention was used to explore the mechanism of Rg1 and signaling metabolite. ResultsRg1 improved UMS-induced despair, anxiety-like and social avoidance behaviors in mice, which were accompanied by increased hypothalamic oxytocin secretion and restored neural proliferation in the hippocampus. Metabolomic analysis of the gut-brain axis revealed that Rg1 increased the concentration of serum and brain indole-3-acetic acid (IAA), a bacterial metabolite that was partially attributed to the enrichment of Lactobacillus murinus in the gut microbiome. Oral supplementation of IAA mimicked the anti-depressant action of Rg1, while oxytocin receptor antagonist abrogated the anti-depressant effects of both Rg1 and IAA. ConclusionOur work provides a new gut-to-brain signaling mechanism for the antidepressant effects of Rg1. In particular, Rg1 enriches the abundance of Lactobacillus murinus, which in turn increases the level of brain IAA and potentiates hypothalamic oxytocin signal. These findings suggest a promising pathway for producing antidepressant effects through gut-brain crosstalk.

Extremely Low-Frequency Electromagnetic Field (ELF-EMF) Increases Mitochondrial Electron Transport Chain Activities and Ameliorates Depressive Behaviors in Mice.

Compromised mitochondrial electron transport chain (ETC) activities are associated with depression in humans and rodents. However, the effects of the enhancement of mitochondrial ETC activities on depression remain elusive. We recently reported that an extremely low-frequency electromagnetic field (ELF-EMF) of as low as 10 μT induced hormetic activation of mitochondrial ETC complexes in human/mouse cultured cells and mouse livers. Chronic social defeat stress (CSDS) for 10 consecutive days caused behavioral defects mimicking depression in mice, and using an ELF-EMF for two to six weeks ameliorated them. CSDS variably decreased the mitochondrial ETC proteins in the prefrontal cortex (PFC) in 10 days, which were increased by an ELF-EMF in six weeks. CSDS had no effect on the mitochondrial oxygen consumption rate in the PFC in 10 days, but using an ELF-EMF for six weeks enhanced it. CSDS inactivated SOD2 by enhancing its acetylation and increased lipid peroxidation in the PFC. In contrast, the ELF-EMF activated the Sirt3-FoxO3a-SOD2 pathway and suppressed lipid peroxidation. Furthermore, CSDS increased markers for mitophagy, which was suppressed by the ELF-EMF in six weeks. The ELF-EMF exerted beneficial hormetic effects on mitochondrial energy production, mitochondrial antioxidation, and mitochondrial dynamics in a mouse model of depression. We envisage that an ELF-EMF is a promising therapeutic option for depression.

A highly specific two-photon fluorescent probe for real-time monitoring of acetylcholinesterase in neurogenic disorders in vivo

Acetylcholinesterase (AChE) hydrolyses choline into thiocholine, which is essential for cholinergic neurons to revert to their resting state following activation. Abnormal changes in AChE activity can directly affect nervous system function. Thus, the specific detection of AChE activity is urgently needed for elucidating the function of the nervous system and diagnosing AChE-related diseases. Current methods for detecting AChE activity have several limitations, including strong background interference and poor tissue penetration. Thus, we designed and synthesized a two-photon (TP) excited fluorescent probe, WZ-AChE, for the specific detection of AChE. Briefly, a carbamate bond was chosen to specifically recognize AChE, which can also be cleaved by AChE. The product, WZ, released strong deep red fluorescence signal under TP excitation at 800 nm. Our results showed that WZ-AChE can detect AChE activity in PC12 cells with both superior sensitivity and selectivity. In addition, we successfully applied WZ-AChE to a C. elegans Parkinson's disease (PD) model and a mouse model of depression. The findings revealed that AChE activity was greater in both disease models than in the control group. To summarize, a novel tool was created to investigate the mechanisms underlying PD and depression.

Development and Validation of a Comprehensive Prognostic and Depression Risk Index for Gastric Adenocarcinoma

Depressive disorder contributes to the initiation and prognosis of patients with cancer, but the interaction between cancer and depressive disorder remains unclear. We generated a gastric adenocarcinoma patient-derived xenograft mice model, treated with chronic unpredictable mild stimulation. Based on the RNA-sequence from the mouse model, patient data from TCGA, and MDD-related (major depressive disorder) genes from the GEO database, 56 hub genes were identified by the intersection of differential expression genes from the three datasets. Molecular subtypes and a prognostic signature were generated based on the 56 genes. A depressive mouse model was constructed to test the key changes in the signatures. The signature was constructed based on the NDUFA4L2, ANKRD45, and AQP3 genes. Patients with high risk-score had a worse overall survival than the patients with low scores, consistent with the results from the two GEO cohorts. The comprehensive results showed that a higher risk-score was correlated with higher levels of tumor immune exclusion, higher infiltration of M0 macrophages, M2 macrophages, and neutrophils, higher angiogenetic activities, and more enriched epithelial–mesenchymal transition signaling pathways. A higher risk score was correlated to a higher MDD score, elevated MDD-related cytokines, and the dysfunction of neurogenesis-related genes, and parts of these changes showed similar trends in the animal model. With the Genomics of Drug Sensitivity in Cancer database, we found that the gastric adenocarcinoma patients with high risk-score may be sensitive to Pazopanib, XMD8.85, Midostaurin, HG.6.64.1, Elesclomol, Linifanib, AP.24534, Roscovitine, Cytarabine, and Axitinib. The gene signature consisting of the NDUFA4L2, ANKRD45, and AQP3 genes is a promising biomarker to distinguish the prognosis, the molecular and immune characteristics, the depressive risk, and the therapy candidates for gastric adenocarcinoma patients.

Role of SIRT1-mediated synaptic plasticity and neurogenesis: Sex-differences in antidepressant-like efficacy of catalpol

BackgroundCatalpol, an important compound found in Rehmannia glutinosa (a plant with high nutritional and antidepressant medicinal value), exhibits various biological activities and has the ability to penetrate the blood-brain barrier. Our recent studies revealed a gender difference in the antidepressant activity of Rehmannia glutinosa with females showing better responses than males. Catalpol is likely the key compound responsible for this gender-specific difference, which caters to current clinical observations that the severity and impact of depression are approximately two to three times higher in females than in males. However, the sex-specific mechanism of catalpol's antidepressant effects remains unclear. Purpose and MethodsOur recent molecular network predictions suggest that the gender-specific antidepressant properties of catalpol primarily involve the regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Building on this, the present study used a well-established chronic unpredictable mild stress model of depression in mice to confirm the sex-specific antidepressant characteristics of catalpol over time and intensity. Furthermore, using SIRT1 inhibitors and activators, behavioral tests, hematoxylin & eosin, Nissl, and Golgi staining, western blotting, immunofluorescence, and real-time PCR, we evaluated the key indicators of depressive behavior, synaptic plasticity, and neurogenesis before and after SIRT1 intervention to comprehensively assess whether the sex-specific antidepressant mechanism of catalpol indeed involves SIRT1-mediated synaptic plasticity and neurogenesis. ResultsThe gender-dependent antidepressant effects of catalpol are characterized by a faster onset and stronger effects in females compared to males, with females showing stronger regulation of SIRT1-mediated synaptic plasticity and neurogenesis. Activation of SIRT1 preserved the gender differences in catalpol's effects on depressive behavior, hippocampal synaptic plasticity (including neuronal consolidation, neuronal density, dendritic spines, and PSD95 and SYP gene and protein expression), and neurogenesis (including enhancement of GAP43 and MAP2 expression, activation of c-myc, cyclinD1, Ngn2, and NeuroD1 mRNA levels, and upregulation of the Wnt3a/β-catenin/GSK-3β pathway), while inhibition of SIRT1 abolished these gender differences in the effects of catalpol. ConclusionsCatalpol exhibits higher antidepressant activity in female mice compared to male mice, and the mechanism underlying this gender difference in antidepressant effects may depend on catalpol's higher sensitivity in improving hippocampal SIRT1-mediated synaptic plasticity and neurogenesis in females. The novelty of this study lies in its first-time revelation of the gender-specific phenotypes, targets, and molecular mechanisms of the antidepressant effects of catalpol.

A metabolomics approach reveals the pharmacological effects and mechanisms of Cistanche tubulosa stems and its combination with fluoxetine on depression in comorbid with sexual dysfunction

Ethnopharmacological relevanceThe dried succulent stems of Cistanche tubulosa (Schenk) Wight are utilized in traditional medicine for tonifying kidney yang, which have shown to be effective in alleviating depression-like behaviors or male sexual dysfunction, respectively. However, the pharmacological effects and mechanisms of C. tubulosa and its combinations in the treatment of depression in comorbid with sexual dysfunction remain unclear. Aim of the studyThis study aims to elucidate the pharmacological effects and mechanisms of C. tubulosa aqueous extract (CTE) and its combination with fluoxetine (FLX) on depression in comorbid with sexual dysfunction. Materials and methodsA mouse model of depression in comorbid with sexual dysfunction was created using the chronic unpredictable mild stress (CUMS) procedure. The therapeutic effects of CTE and its combination with FLX were assessed using depressive-like and mating behavior experiments, histopathological analysis, and hypothalamic-pituitary-gonadal (HPG) axis function evaluation. The mechanisms were explored by integrated serum and testicular metabolomics combined with network correlation analysis. ResultsCTE was confirmed to significantly improve depressive-like behaviors, reduce mating abilities, testicular histopathological damage, and HPG axis hormone secretion disorders in CUMS mice. Subsequently, mechanism exploration findings indicated that CTE might exert its effect by regulating potential efficacy-related biomarkers (isobutyrylglycine, citric acid, D-galactose) to improve certain metabolic pathways centered around steroid hormone biosynthesis and tricarboxylic acid (TCA) cycle. Furthermore, the combination of CTE and FLX exhibited stronger antidepressant effects than FLX alone, and ameliorated the exacerbated sexual dysfunction induced by FLX. These effects were achieved through the regulation of potential efficacy-related biomarkers (17α-hydroxypregnenolone, tetrahydrodeoxy-corticosterone, sphingosine, cortol, thymine, and L-histidine), thereby improving disorders in glycerophospholipid and histidine metabolism. ConclusionIn conclusion, the amelioration effects of CTE and its combination with FLX on depression in comorbid with sexual dysfunction were confirmed for the first time. This key mechanism may be achieved by modulating the levels of potential efficacy-related biomarkers, and then emphatically intervene in steroid hormone biosynthesis, TCA cycle, glycerophospholipid and histidine metabolism. The study offers a new perspective for the development and utilization of C. tubulosa.

Effects of chronic unpredictable mild stress-induced depression on bitter taste receptor expression in mice

ObjectiveWith the rapid increase in the pace of life, people are facing increasing pressures of all kinds, and depression has gradually become a serious psychological disorder in human society, strongly affecting normal social and physiological activities. Depression can disrupt an individual's taste perception and potentially result in taste disorders by affecting and altering taste receptors. This disruption can consequently impact their food preferences and overall eating experiences. DesignIn this study, we used the chronic unpredictable mild stress (CUMS) method to establish a depression model in male C57BL/6 J mice and explored the changes in taste receptor expression in the lingual circumvallate papillae (CP) to elucidate the effects of depression on taste. After 6 weeks of CUMS, behavioral performance evaluations, such as forced swim, open field, and elevated plus maze tests, were conducted in depression model mice. A further two-bottle choice test was subsequently performed to determine the effect of depression on bitter taste, and the expression of bitter taste receptors in the lingual CP was detected via immunofluorescence staining. ResultsIn this study, we found for the first time that mice with CUMS-induced depression had decreased bitter taste sensitivity through a two-bottle choice test and demonstrated that the expression of T2r5, a receptor related to bitter taste perception, and the expression of secondary taste signaling proteins in the lingual CP were significantly decreased in mice exposed to CUMS, as determined via qRTPCR and immunofluorescence staining. ConclusionsOur study highlights how CUMS influences the perception of bitterness in the peripheral taste system, potentially elucidating stress-induced changes in eating habits.

Evaluation of Anti-Depressant Potential of Standardized Hydroethanolic Extract of S. barbata D. Don Using Chronic Unpredictable Mild Stress Model

Background: S. barbata D. Don is a Chinese herb, that belongs to the family Lami-aceae. It has established traditional use in ethnomedicine for treating various ailments, includ-ing mood disorders and sleep disorders, which led to growing interest in exploring its neuro-logical potential, particularly as a potential anti-depressant agent. Aims: This study explores the anti-depressant potential of the HSBE utilizing a Chronic Un-predictable Mild Stress-induced depression model in mice. Additionally, the research aims to elucidate the underlying mechanisms of action. Methods: Swiss albino mice were subjected to a 3-week CUMS paradigm and subsequently administered HSBE at doses of 200 and 400 mg/kg via oral administration. The behavioral alterations were evaluated using the FST, TST, OFT, and SPT. Brain levels of serotonin, dopa-mine, and nor-epinephrine were estimated in different brain regions (cortex, hippocampus, and hypothalamus) to uncover the molecular mechanism. Additionally, assays for monoamine oxi-dase-A, monoamine oxidase-B, and antioxidant enzyme activities were conducted. Plasma ni-trite and corticosterone levels were also measured to get further insight into potential mecha-nisms underlying the anti-depressant effects of HSBE. Results: HSBE significantly ameliorated depressive-like behavior induced by CUMS para-digm, as evidenced by reduced immobility in FST and TST, increased locomotor activity in OFT, and improved sucrose preference in SPT. Neurochemical analysis revealed a significant increase in serotonin, dopamine, and norepinephrine levels in the cortex, hippocampus, and hypothalamus of HSBE-treated mice, implying a potential regulation of monoaminergic neuro-transmitter levels. Moreover, biochemical analyses demonstrated a significant inhibition of both MAO-A and MAO-B activity, contributing to the increase of the brain levels of neuro-transmitters. The administration of HSBE also led to a significant enhancement of antioxidant enzyme activities and reduced brain lipid peroxidation, indicating a pronounced antioxidant effect of HSBE. Furthermore, decreased plasma nitrite and corticosterone levels provided ad-ditional insights into HSBE's potential multi-targeted anti-depressant mechanism. Conclusion: This study indicates that HSBE exhibits robust anti-depressant properties, sup-ported by behavioral, neurochemical, and biochemical alterations. These findings underscore the therapeutic promise of HSBE as a natural intervention for depressive disorders, warranting further clinical exploration.

Upregulation of Phosphodiesterase 7A Contributes to Concurrent Pain and Depression via Inhibition of cAMP-PKA-CREB-BDNF Signaling and Neuroinflammation in the Hippocampus of Mice.

Phosphodiesterases (PDEs) are enzymes that catalyze the hydrolysis of cyclic adenosine monophosphate AMP (cAMP) and/or cyclic guanosine monophosphate (cGMP). PDE inhibitors can mitigate chronic pain and depression when these disorders occur individually; however, there is limited understanding of their role in concurrent chronic pain and depression. We aimed to evaluate the mechanisms of action of PDE using 2 mouse models of concurrent chronic pain and depression. C57BL/6J mice were subjected to partial sciatic nerve ligation (PSNL) to induce chronic neuropathic pain or injected with complete Freund's adjuvant (CFA) to induce inflammatory pain, and both animals showed depression-like behavior. First, we determined the change in PDE expression in both animal models. Next, we determined the effect of PDE7 inhibitor BRL50481 or hippocampal PDE7A knockdown on PSNL- or CFA-induced chronic pain and depression-like behavior. We also investigated the role of cAMP-protein kinase A (PKA)-cAMP response element binding protein (CREB)-brain-derived neurotrophic factor (BDNF) signaling and neuroinflammation in the effect of PDE7A inhibition on PSNL- or CFA-induced chronic pain and depression-like behavior. This induction of chronic pain and depression in the 2 animal models upregulated hippocampal PDE7A. Oral administration of PDE7 inhibitor, BRL50481, or hippocampal PDE7A knockdown significantly reduced mechanical hypersensitivity and depression-like behavior. Hippocampal PDE7 inhibition reversed PSNL- or CFA-induced downregulation of cAMP and BDNF and the phosphorylation of PKA, CREB, and p65. cAMP agonist forskolin reversed these changes and caused milder behavioral symptoms of pain and depression. BRL50481 reversed neuroinflammation in the hippocampus in PSNL mice. Hippocampal PDE7A mediated concurrent chronic pain and depression in both mouse models by inhibiting cAMP-PKA-CREB-BDNF signaling. Inhibiting PDE7A or activating cAMP-PKA-CREB-BDNF signaling are potential strategies to treat concurrent chronic pain and depression.

Intranasal Delivery of circATF7IP siRNA via Lipid Nanoparticles Alleviates LPS-induced Depressive-Like Behaviors.

Major depressive disorder (MDD) is a prevalent mental disorder that significantly impacts social and psychological function, but no effective medication is currently available. Circular RNAs (circRNAs) have been reported to participate in the pathogenesis of MDD which are envisioned as promising therapeutic targets. However, nonviral-based delivery strategies targeting circRNA against MDD are not thoroughly investigated. Here, it is identified that circATF7IP is significantly upregulated in plasma samples and positively correlated with 24-Hamilton Depression Scale (HAMD-24) scores of MDD patients. Synergistic amine lipid nanoparticles (SALNPs) are designed to deliver siRNA targeting circATF7IP (si-circATF7IP) into the hippocampus brain region by intranasal administration. Intranasal delivery of SALNP-si-circATF7IP successfully alleviated the depressive-like behaviors in the LPS-induced mouse depression model via decreasing CD11b+CD45dim microglia population and pro-inflammatory cytokine productions (TNF-α and IL-6). These results indicate that the level of circATF7IP positively correlates with MDD pathogenesis, and SALNP delivery of si-circATF7IP via intranasal administration is an effective strategy to ameliorate LPS-induced depressive-like behaviors.

Efficacy of agomelatine on sleep disorders and lateral habenula neuronal activity in chronic restraint stress depression model mice.

Sleep disorders (SD) are one of the common manifestations of depression patients. This article aimed to explore the effect of Agomelatine (Ago) on SD in chronic restraint stress (CRS) depression model mice and its effect on the activity of neurons in the lateral habenula (LHb). 30 C57BL/6J mice were divided into normal (C57BL/6J) group, CRS group, and Ago group. CRS experiment was used to establish the depression model, and Ago was used to treat CRS mice. Based on behavioral tests in mice and electrophysiology record, SD and LHb neuron activity were assessed. The expression levels of brain-derived neurotrophic factor (BDNF) and nuclear phosphoprotein (c-Fos) in LHb were detected by Western blot (WB). As against the CRS group, the Ago group had a reduction in the immobility time during forced swimming training and an increase in the preference for sucrose in the sucrose preference test; The expression levels of c-Fos and BDNF proteins in the LHb neurons of the Ago group mice were lower than those in the CRS group (P < 0.05), and the values approached the levels of the normal control group. In both dark and light environments, the rapid eye movement (REM) sleep duration of the CRS group mice was significantly longer than that of the normal control group (P < 0.05). It was concluded that Ago may intervene in the depressive-like behavior and overall sleep patterns of CRS depression model mice by regulating the activity of LHb neurons and inhibiting the neuroinflammatory process. This provides a potential drug target for the development of new treatment strategies for depression.

Antidepressant Effects of Ginsenoside Rc on L-Alpha-Aminoadipic Acid-Induced Astrocytic Ablation and Neuroinflammation in Mice.

Depression is a prevalent and debilitating mental disorder that affects millions worldwide. Current treatments, such as antidepressants targeting the serotonergic system, have limitations, including delayed onset of action and high rates of treatment resistance, necessitating novel therapeutic strategies. Ginsenoside Rc (G-Rc) has shown potential anti-inflammatory and neuroprotective effects, but its antidepressant properties remain unexplored. This study investigated the antidepressant effects of G-Rc in an L-alpha-aminoadipic acid (L-AAA)-induced mouse model of depression, which mimics the astrocytic pathology and neuroinflammation observed in major depressive disorder. Mice were administered G-Rc, vehicle, or imipramine orally after L-AAA injection into the prefrontal cortex. G-Rc significantly reduced the immobility time in forced swimming and tail suspension tests compared to vehicle treatment, with more pronounced effects than imipramine. It also attenuated the expression of pro-inflammatory cytokines (TNF-α, IL-6, TGF-β, lipocalin-2) and alleviated astrocytic degeneration, as indicated by increased GFAP and decreased IBA-1 levels. Additionally, G-Rc modulated apoptosis-related proteins, decreasing caspase-3 and increasing Bcl-2 levels compared to the L-AAA-treated group. These findings suggest that G-Rc exerts antidepressant effects by regulating neuroinflammation, astrocyte-microglia crosstalk, and apoptotic pathways in the prefrontal cortex, highlighting its potential as a novel therapeutic agent for depression.

Impacts of Electroconvulsive Therapy on the Neurometabolic Activity in a Mice Model of Depression: An Ex Vivo 1H-[13C]-NMR Spectroscopy Study

Electroconvulsive therapy (ECT) is an effective treatment for severe and drug-resistant depression, yet its mode of action remains poorly understood. This study aimed to evaluate the effects of ECT on neurometabolism using ex vivo 1H-[13C]-NMR spectroscopy in conjunction with intravenous infusion of [1,6-13C2]glucose in a chronic variable mild stress (CVMS) model of depression. Both CVMS and control mice were subjected to seven sessions of electroconvulsive shock under mild isoflurane anesthesia. The CVMS mice exhibited a reduction in sucrose preference (CVMS 67.1 ± 14.9%, n = 5; CON 86.5 ± 0.6%, n = 5; p = 0.007), and an increase in immobility duration (175.9 ± 22.6 vs. 92.0 ± 23.0 s, p &lt; 0.001) in the forced-swim test. The cerebral metabolic rates of glucose oxidation in glutamatergic (CMRGlc(Glu)) (CVMS 0.134 ± 0.015 µmol/g/min, n = 5; CON 0.201 ± 0.045 µmol/g/min, n = 5; padj = 0.04) and GABAergic neurons (CMRGlc(GABA)) (0.030 ± 0.002 vs. 0.046 ± 0.011 µmol/g/min, padj = 0.04) were reduced in the prefrontal cortex (PFC) of CVMS mice. ECT treatment in CVMS mice normalized sucrose preference [F(1,27) = 0.0024, p = 0.961] and immobility duration [F(1,28) = 0.434, p = 0.515], but not the time spent in the center zone (CVMS + ECT 10.4 ± 5.5 s, CON + sham 22.3 ± 11.4 s, padj = 0.0006) in the open field test. The ECT-treated CVMS mice exhibited reduced (padj = 0.021) CMRGlc(Glu) in PFC (0.169 ± 0.026 µmol/g/min, n = 8) when compared with CVMS mice, which underwent the sham procedure (0.226 ± 0.030 µmol/g/min, n = 8). These observations are consistent with ECT’s anticonvulsant hypothesis for its anti-depressive action.

RIPK1 inhibition mitigates neuroinflammation and rescues depressive-like behaviors in a mouse model of LPS-induced depression

BackgroundDepression is often linked to inflammation in the brain. Researchers have been exploring ways to reduce this inflammation to improve depression symptoms. One potential target is a protein called RIPK1, which is known to contribute to brain inflammation. However, it’s unclear how RIPK1 influences depression. Our study aims to determine whether RIPK1 inhibition could alleviate neuroinflammation-associated depression and elucidate its underlying mechanisms.MethodsTo investigate our research objectives, we established a neuroinflammation mouse model by administering LPS. Behavioral and biochemical assessments were conducted on these mice. The findings were subsequently validated through in vitro experiments.ResultsUsing LPS-induced depression models, we investigated RIPK1’s role, observing depressive-like behaviors accompanied by elevated cytokines, IBA-1, GFAP levels, and increased inflammatory signaling molecules and NO/H2O2. Remarkably, Necrostatin (Nec-1 S), a RIPK1 inhibitor, mitigated these changes. We further found altered expression and phosphorylation of eIF4E, PI3K/AKT/mTOR, and synaptic proteins in hippocampal tissues, BV2, and N2a cells post-LPS treatment, which Nec-1 S also ameliorated. Importantly, eIF4E inhibition reversed some of the beneficial effects of Nec-1 S, suggesting a complex interaction between RIPK1 and eIF4E in LPS-induced neuroinflammation. Moreover, citronellol, a RIPK1 agonist, significantly altered eIF4E phosphorylation, indicating RIPK1’s potential upstream regulatory role in eIF4E and its contribution to neuroinflammation-associated depression.ConclusionThese findings propose RIPK1 as a pivotal mediator in regulating neuroinflammation and neural plasticity, highlighting its significance as a potential therapeutic target for depression.

Antidepressant-like effect of riparin I and riparin II against CUMS-induced neuroinflammation via astrocytes and microglia modulation in mice.

Depression is a common mood disorder and many patients do not respond to conventional pharmacotherapy or experience a variety of adverse effects. This work proposed that riparin I (RIP I) and riparin II (RIP II) present neuroprotective effects through modulation of astrocytes and microglia, resulting in the reversal of depressive-like behaviors. To verify our hypothesis and clarify the pathways underlying the effect of RIP I and RIP II on neuroinflammation, we used the chronic unpredictable mild stress (CUMS) depression model in mice. Male Swiss mice were exposed to stressors for 28 days. From 15 th to the 22 nd day, the animals received RIP I or RIP II (50 mg/kg) or fluoxetine (FLU, 10 mg/kg) or vehicle, by gavage. On the 29 th day, behavioral tests were performed. Expressions of microglia (ionized calcium-binding adaptor molecule-1 - Iba-1) and astrocyte (glial fibrillary acidic protein - GFAP) markers and levels of cytokines tumor necrosis factor alfa (TNF-α) and interleukin 1 beta (IL-1β) were measured in the hippocampus. CUMS induced depressive-like behaviors and cognitive impairment, high TNF-α and IL-1β levels, decreased GFAP, and increased Iba-1 expressions. RIP I and RIP II reversed these alterations. These results contribute to the understanding the mechanisms underlying the antidepressant effect of RIP I and RIP II, which may be related to neuroinflammatory suppression.

Ameliorating Effect of Standardized Rice Bran Supplement on Depressive-Like Behaviors in Ovariectomized Mice.

Menopausal depression, often associated with hormonal fluctuations such as decreased estrogen levels, imposes significant mental health burdens. Despite the antidepressant biological properties of standardized rice bran supplement (RBS), its impact on menopausal depression and underlying mechanisms remains largely unexplored. In this study, we investigated the antidepressant effects of RBS in a mouse model of estrogen deficiency-induced depression. Ovariectomized (OVX) mice received oral doses of RBS (250 and 1000 mg/kg) and 17β estradiol over a 20-week period. RBS administration resulted in decreased immobility time in the tail suspension and forced swim tests, along with increased locomotor activity in the open field test. Furthermore, RBS enhanced nitric oxide production and neuronal nitric oxide synthase (nNOS) expression in the hippocampi of OVX mice. Additionally, RBS administration phosphorylated extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), and tropomyosin receptor kinase B and increased the protein expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. These findings suggest that RBS alleviated depressive behaviors in OVX mice by augmenting hippocampal nNOS expression and activating the ERK-CREB-BDNF signaling pathway. Therefore, based on these results, we propose that RBS is a promising agent to treat menopausal depression, a challenging condition.

Depression exacerbates myocardial ischemia-reperfusion injury in mice via CNR2 gene and MIF-AMPK signaling pathway

BackgroundMyocardial ischemia-reperfusion(I/R)injury constitute the fundamental pathophysiology of acute myocardial infarction (AMI). Ischemic heart releases macrophage migration inhibitory factor (MIF), which activates MIF- AMPK signaling pathway. Depression is a significant risk factor for AMI. In a state of depression, peripheral expression of cannabinoid receptor 2 (CNR2) genes was downregulated. AimsWe investigated the mechanism by which depression exacerbates myocardial I/R injury through the CNR2 and MIF-AMPK signaling pathways. MethodsWe established mouse models of depression and myocardial I/R. Left ventricular function was assessed using cardiac ultrasound and TTC staining. The protein levels of myocardial CNR2, MIF, AMPK, and ACC were determined by Western blot, while the expression level of CNR2 was measured using RT-qPCR. Additionally, MIF content in peripheral blood was quantified using ELISA. ResultsAfter I/R, the expression level of CNR2 was found to be lower in the depression group, leading to a deterioration in left heart function. Depressed mice exhibited lower secretion of MIF, accompanied by a decrease in the activation of the MIF-AMPK signaling pathway. However, injection of CNR2 agonist JWH133 prior to ischemia increased the activation of the MIF-AMPK signaling pathway, while CNR2 inhibitor AM630 decreased the activation. LimitationsFurther research is needed to investigate the specific neuroendocrine mechanism affecting myocardial CNR2 expression in depression. And these experimental conclusions require further verification at the cellular level. ConclusionsThe activation of CNR2 in myocardium following I/R is impeded by depression, thereby exacerbating myocardial I/R injury through attenuation of the MIF-AMPK signaling pathway activation.