Involvement of PI3K/Akt/GSK-3β and mTOR in the antidepressant-like effect of atorvastatin in mice

Neuroprotective effects of total phenolics from Hemerocallis citrina Baroni leaves through the PI3K/AKT pathway

Neurological injury, as a major pathogenic mechanism in depression, holds significant importance in the research and development of antidepressant drugs. Hemerocallis citrina Baroni (H. citrina), referred to as "Forgetting Sadness Grass," has been confirmed to possess remarkable neuroprotective effects. Studies have identified that the total phenolics in H. citrina Baroni leaves (HLTP) consist of flavonoids and phenolic acids and numerous studies have substantiated the neuroprotective effects of them. Based on this, we propose that HLTP may possess neuroprotective properties. To confirm this hypothesis, we initially employed network pharmacology techniques to predict potential targets for the neuroprotective effects of HLTP based on the Swiss Target Prediction database. GO and KEGG analyses were conducted to predict potential pathways, and a component-target-pathway network was constructed. Molecular docking experiments were then performed to analyze the binding abilities of the selected active components with the main targets. Furthermore, we validated the neuroprotective effects of HLTP and key targets selected through network pharmacology using a corticosterone-induced PC12 neuronal cell damage model. Network pharmacology research has identified that in the HLTP, Quercetin, Rutin, Apigenin, and Isoquercitrin are potential active components that may exert neuroprotective effects by modulating key targets such as AKT1, TNF, TP53, and CASP3 through crucial pathways including PI3K/AKT and apoptosis. Molecular docking revealed that 4-O-Caffeoylquinic acid, 5-O-Caffeoylshikimic acid, 4-p-Coumaroylquinic acid, and 5-O-Feruloylquinic acid exhibit low binding energies with key targets. Particularly, 4-O-Caffeoylquinic acid forms stable binding through hydrogen bonding with residues such as LYS389, GLU49, GLN47, LYS30, ASP44, and GLU40 in AKT1. PC12 cells were stimulated with 200 μmol/L Corticosterone (Cort) for 24 h, and then treated with 50, 100 and 200 μg/mL of HLTP for 24 h. The cell viability of damaged cells were significantly increased in a dose-dependent manner by 9.50%, 10.42% and 21.25%, respectively (P < 0.01). Western blot analysis confirmed that HLTP significantly (P < 0.01) increased the protein expression of PI3K and AKT by 15.24%, 30.44%, 41.03%, and 21.78%, 43.63%, 12.86%, respectively. In addition, through biochemical method, flow cytometry and WB analysis, we found that different concentrations of HLTP can all improve cell damage by reducing ROS, MDA, Ca2+, Cyt-C, Caspase-3, TNF-α and IL-1β, and increasing SOD, CAT, MMP, Bcl-2/Bax and IL-10. In particular, the HLTP at 200 μg/mL, compared with the Model group, decreased by 140.2%, 54.66%, 51.34%, 65.26%, 40.32%, 63.87%, and 55.38%, and increased by 39.65%, 35.45%, 38.38%, 28.54%, and 39.98%, respectively. Through the above experiments, we verified that HLTP may exert neuroprotective effects by mediating the PI3K/AKT signaling pathway to counteract oxidative stress damage, improve mitochondrial dysfunction, and alleviate inflammatory injury.

Cognitive improving actions of tofacitinib in a mouse model of Alzheimer disease involving TNF-α, IL-6, PI3K-Akt and GSK-3β signalling pathway

Aim and Objective: This current study investigated the significance of tofactinib in improving memory functions in a memory model of β-amyloid (Aβ)-induced dementia.Material and Methods: Aβ1-42 was injected in the brain of mice using intracerebroventricular injection and after 14 days, the learning and memory was assessed on the Morris Water maze test. Mice were treated with tofactinib (10, 20, 30 mg/kg) two days prior to Aβ1-42 injection and 14 days after Aβ injection.Results: Treatment of tofactinib significantly improved the learning (decrease in day escape latency time [ELT]) and memory (increase in time spent in target quadrant). This drug also decreased the levels of T NF-α and IL-6 along with the rise in expression of p-Akt and p-GSK-3β/GSK-3β ratio in mice brain. Co-administration of LY294002 (P I3K inhibitor) or MK-2206 2HCl (Akt inhibitor) with tofactinib (30 mg/kg) obliterated the beneficial effects of the latter by increasing T NF-α and IL-6 levels along with decreasing the p-Akt expression and p-GSK-3β/GSK-3β ratio.Conclusion: It is concluded that tofactinib improves the condition of dementia of Alzheimer's type, possibly through down regulation of T NF-α and IL-6 and instigation of P I3K-Akt-p-GSK-3β signalling system in the hippocampus of Aβ-treated mice.

Anethole via increase in the gene expression of PI3K/AKT/mTOR mitigates the autistic-like behaviors induced by maternal separation stress in mice

Autism spectrum disorder (ASD) is a neurodegenerative disease with increasing incidence in the world. The maternal separation (MS) stress at early life with its own neuroendocrine and neurostructural changes can provide the basis for development of ASD. Previously it has been reported neuroprotective characteristics for anethole. The PI3K/AKT/mTOR signaling pathway has pivotal role in the function of central nervous system (CNS). This study aimed to evaluate the possible effects of anethole on the autistic-like behaviors in the maternally separated (MS) mice focusing on the potential role of the PI3K/AKT/mTOR pathway. Forty male Naval Medical Research Institute (NMRI) mice were assigned to five groups (n = 8) comprising a control group (treated with normal saline) and four groups subjected to MS and treated with normal saline and or anethole at doses of 31.25, 62.5 and 125 mg/kg, respectively. All gents were administrated via intraperitoneal (i.p.) route for 14 constant days. Behavioral tests were conducted, including the three-chamber test, shuttle box and resident-intruder test. The gene expression of the PI3K, AKT and mTOR assessed in the hippocampus by qRT-PCR. Findings indicated that MS is associated with autistic-like behaviors. Anethole increased the sociability and social preference indexes in the three-chamber test, increased duration of secondary latency in the shuttle box test and decreased aggressive behaviors in the resident-intruder test. Also, anethole increased the gene expression of PI3K, AKT and mTOR in the hippocampus of MS mice. We concluded that anethole through increase in the gene expression of PI3K/ AKT/mTOR mitigated autistic-like behaviors induced by MS in mice.

Involvement of PI3K/AKT Pathway in the Rapid Antidepressant Effects of Crocetin in Mice with Depression-Like Phenotypes

The current first-line antidepressants have the drawback of slow onset, which greatly affects the treatment of depression. Crocetin, one of the main active ingredients in saffron (Crocus sativus L.), has been demonstrated to have antidepressant activities, but whether it has a rapid antidepressant effect remains unclear. This study aimed to investigate the onset, duration, and mechanisms of the rapid antidepressant activity of crocetin (20, 40 and 80 mg/kg, intraperitoneal injection) in male mice subjected to chronic restraint stress (CRS). The results of behavioral tests showed that crocetin exerted rapid antidepressant-like effect in mice with depression-like phenotypes, including rapid normalization of depressive-like behaviors within 3 h, and the effects could be maintained for 2 days. Hematoxylin-eosin (HE) and Nissl staining showed that crocetin ameliorated hippocampal neuroinflammation and nerve injuries in mice with depression-like phenotypes. The levels of inflammatory factors, corticosterone and pro brain-derived neurotrophic factor in crocetin-administrated mice serum were significantly reduced compared with those in the CRS group, as well as the levels of inflammatory factors in hippocampus. What's more, Western blot analyses showed that, compared to CRS-induced mice, the relative levels of mitogen-activated kinase phosphatase 1 and toll-like receptor 4 were significantly reduced after the administration of crocetin, and the relative expressions of extracellular signal-regulated kinase 1/2 (ERK1/2), cAMP-response element binding protein, phosphorylated phosphoinositide 3 kinase (p-PI3K)/PI3K, phosphorylated protein kinase B (p-AKT)/AKT, phosphorylated glycogen synthase kinase 3β (p-GSK3β)/GSK3β, phosphorylated mammalian target of rapamycin (p-mTOR)/mTOR were markedly upregulated. In conclusion, crocetin exerted rapid antidepressant effects via suppressing the expression of inflammatory cytokines and the apoptosis of neuronal cells through PI3K/AKT signaling pathways. The rapid antidepressant effect of crocetin (40 mg/kg) could be maintained for at least 2 days after single treatment.

PI3K-AKT/mTOR Signaling in Psychiatric Disorders: A Valuable Target to Stimulate or Suppress?

Economic development and increased stress have considerably increased the prevalence of psychiatric disorders in recent years, which rank as some of the most prevalent diseases globally. Several factors, including chronic social stress, genetic inheritance, and autogenous diseases, lead to the development and progression of psychiatric disorders. Clinical treatments for psychiatric disorders include psychotherapy, chemotherapy, and electric shock therapy. Although various achievements have been made researching psychiatric disorders, the pathogenesis of these diseases has not been fully understood yet, and serious adverse effects and resistance to antipsychotics are major obstacles to treating patients with psychiatric disorders. Recent studies have shown that the mammalian target of rapamycin (mTOR) is a central signaling hub that functions in nerve growth, synapse formation, and plasticity. The PI3K-AKT/mTOR pathway is a critical target for mediating the rapid antidepressant effects of these pharmacological agents in clinical and preclinical research. Abnormal PI3K-AKT/mTOR signaling is closely associated with the pathogenesis of several neurodevelopmental disorders. In this review, we focused on the role of mTOR signaling and the related aberrant neurogenesis in psychiatric disorders. Elucidating the neurobiology of the PI3K-AKT/mTOR signaling pathway in psychiatric disorders and its actions in response to antidepressants will help us better understand brain development and quickly identify new therapeutic targets for the treatment of these mental illnesses.

The pharmacological bases for repurposing statins in depression: a review of mechanistic studies

Statins are commonly prescribed medications widely investigated for their potential actions on the brain and mental health. Pre-clinical and clinical evidence suggests that statins may play a role in the treatment of depressive disorders, but only the latter has been systematically assessed. Thus, the physiopathological mechanisms underlying statins' putative antidepressant or depressogenic effects have not been established. This review aims to gather available evidence from mechanistic studies to strengthen the pharmacological basis for repurposing statins in depression. We used a broad, well-validated search strategy over three major databases (Pubmed/MEDLINE, Embase, PsychINFO) to retrieve any mechanistic study investigating statins' effects on depression. The systematic search yielded 8068 records, which were narrowed down to 77 relevant papers. The selected studies (some dealing with more than one bodily system) described several neuropsychopharmacological (44 studies), endocrine-metabolic (17 studies), cardiovascular (6 studies) and immunological (15 studies) mechanisms potentially contributing to the effects of statins on mood. Numerous articles highlighted the beneficial effect of statins on depression, particularly through positive actions on serotonergic neurotransmission, neurogenesis and neuroplasticity, hypothalamic-pituitary axis regulation and modulation of inflammation. The role of other mechanisms, especially the association between statins, lipid metabolism and worsening of depressive symptoms, appears more controversial. Overall, most mechanistic evidence supports an antidepressant activity for statins, likely mediated by a variety of intertwined processes involving several bodily systems. Further research in this area can benefit from measuring relevant biomarkers to inform the selection of patients most likely to respond to statins' antidepressant effects while also improving our understanding of the physiopathological basis of depression.

NMDA receptor-mediated modulation on glutamine synthetase and glial glutamate transporter GLT-1 is involved in the antidepressant-like and neuroprotective effects of guanosine

Guanosine has been reported to elicit antidepressant-like responses in rodents, but if these actions are associated with its ability to afford neuroprotection against glutamate-induced toxicity still needs to be fully understood. Therefore, this study investigated the antidepressant-like and neuroprotective effects elicited by guanosine in mice and evaluated the possible involvement of NMDA receptors, glutamine synthetase, and GLT-1 in these responses. We found that guanosine (0.05 mg/kg, but not 0.01 mg/kg, p. o.) was effective in producing an antidepressant-like effect and protecting hippocampal and prefrontocortical slices against glutamate-induced damage. Our results also unveiled that ketamine (1 mg/kg, but not 0.1 mg/kg, i. p, an NMDA receptor antagonist) effectively elicited antidepressant-like actions and protected hippocampal and prefrontocortical slices against glutamatergic toxicity. Furthermore, the combined administration of sub-effective doses of guanosine (0.01 mg/kg, p. o.) with ketamine (0.1 mg/kg, i. p.) promoted an antidepressant-like effect and augmented glutamine synthetase activity and GLT-1 immunocontent in the hippocampus, but not in the prefrontal cortex. Our results also showed that the combination of sub-effective doses of ketamine and guanosine, at the same protocol schedule that exhibited an antidepressant-like effect, effectively abolished glutamate-induced damage in hippocampal and prefrontocortical slices. Our in vitro results reinforce that guanosine, ketamine, or sub-effective concentrations of guanosine plus ketamine protect against glutamate exposure by modulating glutamine synthetase activity and GLT-1 levels. Finally, molecular docking analysis suggests that guanosine might interact with NMDA receptors at the ketamine or glycine/d-serine co-agonist binding sites. These findings provide support for the premise that guanosine has antidepressant-like effects and should be further investigated for depression management.

Chronic salmon calcitonin exerts an antidepressant effect via modulating the p38 MAPK signaling pathway

Depression is a common recurrent psychiatric disorder with a high lifetime prevalence and suicide rate. At present, although several traditional clinical drugs such as fluoxetine and ketamine, are widely used, medications with a high efficiency and reduced side effects are of urgent need. Our group has recently reported that a single administration of salmon calcitonin (sCT) could ameliorate a depressive-like phenotype via the amylin signaling pathway in a mouse model established by chronic restraint stress (CRS). However, the molecular mechanism underlying the antidepressant effect needs to be addressed. In this study, we investigated the antidepressant potential of sCT applied chronically and its underlying mechanism. In addition, using transcriptomics, we found the MAPK signaling pathway was upregulated in the hippocampus of CRS-treated mice. Further phosphorylation levels of ERK/p38/JNK kinases were also enhanced, and sCT treatment was able only to downregulate the phosphorylation level of p38/JNK, with phosphorylated ERK level unaffected. Finally, we found that the antidepressant effect of sCT was blocked by p38 agonists rather than JNK agonists. These results provide a mechanistic explanation of the antidepressant effect of sCT, suggesting its potential for treating the depressive disorder in the clinic.

Statins block mammalian target of rapamycin pathway: a possible novel therapeutic strategy for inflammatory, malignant and neurodegenerative diseases

Inflammation plays a critical role in several diseases such as cancer, gastric, heart and nervous system diseases. Data suggest that the activation of mammalian target of rapamycin (mTOR) pathway in epithelial cells leads to inflammation. Statins, the inhibitors of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA), seem to be able to inhibit the mTOR. Statins are considered to have favorable effects on inflammatory diseases by reducing the complications caused by inflammation and by regulating the inflammatory process and cytokines secretion. This critical review collected data on this topic from clinical, in vivo and in vitro studies published between 1998 and June 2022 in English from databases including PubMed, Google Scholar, Scopus, and Cochrane libraries.

Role of mTOR1 signaling in the antidepressant effects of ketamine and the potential of mTORC1 activators as novel antidepressants

Conventional antidepressant medications act on monoaminergic systems and have important limitations, including a therapeutic delay of weeks to months and low rates of efficacy. Recently, clinical findings have indicated that ketamine, a dissociative anesthetic that blocks N-methyl-d-aspartate receptor channel activity, causes rapid and long-lasting antidepressant effects. Although the exact mechanisms underlying the antidepressant effects of ketamine are not fully known, preclinical studies have demonstrated a key role for mechanistic target of rapamycin complex 1 (mTORC1) signaling and a subsequent increase in synapse formation in the medial prefrontal cortex. In this review, we discuss the role of mTORC1 and its subsequent signaling cascade in the antidepressant effects of ketamine and other compounds with glutamatergic mechanisms of action. We also present the possibility that mTORC1 signaling itself is a drug discovery target.

Statins in depression: a repurposed medical treatment can provide novel insights in mental health

Depression has a large burden, but the development of new drugs for its treatment has proved difficult. Progresses in neuroscience have highlighted several physiopathological pathways, notably inflammatory and metabolic ones, likely involved in the genesis of depressive symptoms. A novel strategy proposes to repurpose established medical treatments of known safety and to investigate their potential antidepressant activity. Among numerous candidates, growing evidence suggests that statins may have a positive role in the treatment of depressive disorders, although some have raised concerns about possible depressogenic effects of these widely prescribed medications. This narrative review summarises relevant findings from translational studies implicating many interconnected neurobiological and neuropsychological, cardiovascular, endocrine-metabolic, and immunological mechanisms by which statins could influence mood. Also, the most recent clinical investigations on the effects of statins in depression are presented. Overall, the use of statins for the treatment of depressive symptoms cannot be recommended based on the available literature, though this might change as several larger, methodologically robust studies are being conducted. Nevertheless, statins can already be acknowledged as a driver of innovation in mental health, as they provide a novel perspective to the physical health of people with depression and for the development of more precise antidepressant treatments.

A comparison of reinforcing effectiveness and drug-seeking reinstatement of 2-fluorodeschloroketamine and ketamine in self-administered rats

2-Fluorodeschloroketamine (2F-DCK), a structural analog of ketamine, has been reported to cause impaired consciousness, agitation, and hallucination in abuse cases. It has similar reinforcing and discriminative effects as ketamine. However, the reinforcing efficacy and drug-seeking reinstatement of this analog have not been clarified to date. In this study, the effectiveness of 2F-DCK and ketamine was compared using a behavioral economics demand curve. The reinstatement of 2F-DCK- and ketamine-seeking behaviors induced by either conditioned cues or self-priming was also analyzed. Rats were intravenously self-administered 2F-DCK and ketamine at a dose of 0.5 mg/kg/infusion under a reinforcing schedule of fixed ratio 1 (FR1) with 4 h of daily training for at least 10 consecutive days. The elasticity coefficient parameter α and the essential value of the demand curve in the two groups were similar. Both groups of rats showed significant drug-seeking behavior induced either by conditional cues or by 2F-DCK and ketamine priming. Moreover, the α parameter was inversely related to the degree of reinstatement induced by cues or drug priming in both groups. In total, the expression levels of brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element-binding protein (p-CREB) in the nucleus accumbens in both extinguished and reinstated rats were significantly lower than those in the control. The expression of total Akt, glycogen synthase kinase (GSK)-3β, mammalian target of rapamycin (mTOR), and extracellular signal-related kinase (ERK) also decreased, but p-Akt, p-GSK-3β, p-mTOR, and p-ERK levels increased in both extinguished and reinstated rats. This is the first study to demonstrate that 2F-DCK has similar reinforcing efficacy, effectiveness, and post-withdrawal cravings as ketamine after repeated use. These data suggest that the downregulation of CREB/BDNF and the upregulation of the Akt/mTOR/GSK-3β signaling pathway in the nucleus accumbens may be involved in ketamine or 2F-DCK relapse.

Mathematical algorithm–based identification of the functional components and mechanisms in depression treatment: An example of Danggui-Shaoyao-San

Depression, a complex epidemiological mental disorder, affects around 350 million people worldwide. Despite the availability of antidepressants based on monoamine hypothesis of depression, most patients suffer side effects from these drugs, including psychomotor impairment and dependence liability. Traditional Chinese medicine (TCM) is receiving more and more attention due to the advantages of high therapeutic performance and few side effects in depression treatment. However, complex multicomponents and multi-targets in TCM hinder our ability to identify the functional components and molecular mechanisms of its efficacy. In this study, we designed a novel strategy to capture the functional components and mechanisms of TCM based on a mathematical algorithm. To establish proof of principle, the TCM formula Danggui-Shaoyao-San (DSS), which possesses remarkable antidepressant effect but its functional components and mechanisms are unclear, is used as an example. According to the network motif detection algorithm, key core function motifs (CIM) of DSS in treating depression were captured, followed by a functional analysis and verification. The results demonstrated that 198 pathways were enriched by the target genes of the CIM, and 179 coincided with the enriched pathways of pathogenic genes, accounting for 90.40% of the gene enrichment pathway of the C-T network. Then the functional components group (FCG) comprising 40 components was traced from CIM based on the target coverage accumulation algorithm, after which the pathways enriched by the target genes of FCG were selected to elucidate the potential mechanisms of DSS in treating depression. Finally, the pivotal components in FCG of DSS and the related pathways were selected for experimental validation in vitro and in vivo. Our results indicated good accuracy of the proposed mathematical algorithm in sifting the FCG from the TCM formula, which provided a methodological reference for discovering functional components and interpreting molecular mechanisms of the TCM formula in treating complex diseases.

Network Pharmacology and Molecular Docking Analysis of the Mechanism Underlying Yikunyin's Therapeutic Effect on Menopausal Syndrome

Objective

Yikunyin is an empirical prescription that exhibits good efficacy in the clinical treatment of menopausal syndrome; however, its underlying mechanism remains unclear. This study investigates the mechanism implicated in the therapeutic effect of Yikunyin by identifying its hub genes, central pathways, and key active ingredients.

Method

The active ingredients and targets of Yikunyin were obtained from the Traditional Chinese Medicine Systems Pharmacology database, whereas the targets related to menopausal syndrome were obtained from GeneCards, PharmGKB, Therapeutic Target Database (TTD), and Comparative Toxicogenomics Database (CTD). To reveal the pharmacological mechanism, the component-target and the intersecting protein-protein interaction (PPI) networks were constructed, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. Finally, molecular docking was carried out to assess the strength of binding between the key active ingredients and key targets.

Results

A total of 418 targets and 121 active ingredients were identified in Yikunyin. The intersection of Yikunyin's 418 targets with the 2822 targets related to menopausal syndrome shows that there are 247 common targets that can be considered potential targets of Yikunyin in the treatment of menopausal syndrome. The topology analysis of the constructed PPI network conducted using the Cytoscape software shows that there are 15 hub genes implicated in the therapeutic effect of Yikunyin: AKT1, PRKCA, TLR9, CXCL10, PRKCD, PARP1, ABCB1, TP53, CAV1, MAPK8, PPARA, GRB2, EGFR, IL-6, and JAK2. Moreover, the key active components acting on these genes are paeoniflorin, luteolin, quercetin, beta-sitosterol, and kaempferol. GO and KEGG analyses indicate that Yikunyin can treat menopausal syndrome by regulating cellular response to chemical stress (GO:0062197), cellular response to oxidative stress (GO:0034599), phosphatase binding (GO:0019902), cytokine receptor binding (GO:0005126), PI3K-Akt signaling (hsa04151), lipid and atherosclerosis (hsa05417), and hepatitis B (hsa05161). Finally, the results of molecular docking suggest that the key active ingredients and key targets can bind well, with binding energies of less than −5 kJ/mol.

Conclusion

The research conducted herein reveals that Yikunyin treats menopausal syndrome by targeting AKT1 and IL-6 and by regulating the PI3K-Akt signaling pathway. Moreover, it provides a new idea for understanding the therapeutic effects of traditional Chinese medicines.

Luteolin Modulates Neural Stem Cells Fate Determination: In vitro Study on Human Neural Stem Cells, and in vivo Study on LPS-Induced Depression Mice Model

Luteolin is a natural flavone with neurotrophic effects observed on different neuronal cell lines. In the present study, we aimed to assess the effect of luteolin on hNSCs fate determination and the LPS-induced neuroinflammation in a mouse model of depression with astrocytogenesis defect. hNSCs were cultured in basal cell culture medium (control) or medium supplemented with luteolin or AICAR, a known inducer of astrogenesis. A whole-genome transcriptomic analysis showed that luteolin upregulated the expressions of genes related to neurotrophin, dopaminergic, hippo, and Wnt signaling pathways, and downregulated the genes involved in p53, TNF, FOXO, and Notch signaling pathways. We also found that astrocyte-specific gene GFAP, as well as other genes of the key signaling pathways involved in astrogenesis such as Wnt, BMP, and JAK-STAT pathways were upregulated in luteolin-treated hNSCs. On the other hand, neurogenesis and oligodendrogenesis-related genes, TUBB3, NEUROD 1 and 6, and MBP, were downregulated in luteolin-treated hNSCs. Furthermore, immunostaining showed that percentages of GFAP+ cells were significantly higher in luteolin- and AICAR-treated hNSCs compared to control hNSCs. Additionally, RT-qPCR results showed that luteolin upregulated the expressions of GFAP, BMP2, and STAT3, whereas the expression of TUBB3 remained unchanged. Next, we evaluated the effects of luteolin in LPS-induced mice model of depression that represents defects in astrocytogenesis. We found that oral administration of luteolin (10 mg/Kg) for eight consecutive days could decrease the immobility time on tail suspension test, a mouse behavioral test measuring depression-like behavior, and attenuate LPS-induced inflammatory responses by significantly decreasing IL-6 production in mice brain-derived astrocytes and serum, and TNFα and corticosterone levels in serum. Luteolin treatment also significantly increased mature BDNF, dopamine, and noradrenaline levels in the hypothalamus of LPS-induced depression mice. Though the behavioral effects of luteolin did not reach statistical significance, global gene expression analyses of mice hippocampus and brain-derived NSCs highlighted the modulatory effects of luteolin on different signaling pathways involved in the pathophysiology of depression. Altogether, our findings suggest an astrocytogenic potential of luteolin and its possible therapeutic benefits in neuroinflammatory and neurodegenerative diseases. However, further studies are required to identify the specific mechanism of action of luteolin.

Abnormal expression profile of plasma-derived exosomal microRNAs in patients with treatment-resistant depression

Whether microRNAs (miRNAs) from plasma exosomes might be dysregulated in patients with depression, especially treatment-resistant depression (TRD), remains unclear, based on study of which novel biomarkers and therapeutic targets could be discovered. To this end, a small sample study was performed by isolation of plasma exosomes from patients with TRD diagnosed by Hamilton scale. In this study, 4 peripheral plasma samples from patients with TRD and 4 healthy controls were collected for extraction of plasma exosomes. Exosomal miRNAs were analyzed by miRNA sequencing, followed by image collection, expression difference analysis, target gene GO enrichment analysis, and KEGG pathway enrichment analysis. Compared with the healthy controls, 2 miRNAs in the plasma exosomes of patients with TRD showed significant differences in expression, among which has-miR-335-5p were significantly upregulated and has-miR-1292-3p were significantly downregulated. Go and KEGG analysis showed that dysregulated miRNAs affect postsynaptic density and axonogenesis as well as the signaling pathway of axon formation and cell growths. The identification of these miRNAs and their target genes may provide novel biomarkers for improving diagnosis accuracy and treatment effectiveness of TRD.

Statins in Depression: An Evidence-Based Overview of Mechanisms and Clinical Studies

Background: Depression is a leading cause of disability, burdened by high levels of non-response to conventional antidepressants. Novel therapeutic strategies targeting non-monoaminergic pathways are sorely needed. The widely available and safe statins have several putative mechanisms of action, especially anti-inflammatory, which make them ideal candidates for repurposing in the treatment of depression. A large number of articles has been published on this topic. The aim of this study is to assess this literature according to evidence-based medicine principles to inform clinical practise and research. Methods: We performed a systematic review of the electronic databases MEDLINE, CENTRAL, Web of Science, CINAHL, and ClinicalTrials.gov, and an unstructured Google Scholar and manual search, until the 9th of April 2021, for all types of clinical studies assessing the effects of statins in depression. Results: Seventy-two studies were retrieved that investigated the effects of statins on the risk of developing depression or on depressive symptoms in both depressed and non-depressed populations. Fifteen studies specifically addressed the effects of statins on inflammatory-related symptoms of anhedonia, psychomotor retardation, anxiety, and sleep disturbances in depression. Most studies suggested a positive effect of statins on the occurrence and severity of depression, with fewer studies showing no effect, while a minority indicated some negative effects. Limitations: We provide a narrative report on all the included studies but did not perform any quantitative analysis, which limits the strength of our conclusions. Conclusions: Robust evidence indicates that statins are unlikely to lead to depressive symptoms in the general population. Promising data suggest a potential role for statins in the treatment of depression. Further clinical studies are needed, especially in specific subgroups of patients identified by pre-treatment assessments of inflammatory and lipid profiles.

CGRP overexpression does not alter depression-like behavior in mice

Background

The calcitonin gene-related peptide (CGRP) is a neuropeptide that is released from capsaicin-sensitive nerves as a potent vasodilator involved in nociceptive transmission. While CGRP has been rigorously studied for its role in migraines owing to its vasodilation and inflammation activities, the effects of CGRP overexpression on depressive-like behaviors remain insufficiently understood.

Methods

In the present study, we performed a battery of behavioral tests, including the social interaction test, open field test, and sucrose preference test, to evaluate social defeat stress using male C57BL6J or CGRP overexpression in transgenic (Tg) mice (CGRP Tg). We performed mRNA and protein analyses on the brain-derived neurotrophic factor (BDNF), phosphorylated Akt, mTOR, and p70S6K in the hippocampi.

Results

CGRP Tg mice showed increased levels of Bdnf mRNAs, low locomotor activity, and no deficits in social interaction, which indicate that CGRP Tg mice exhibit stress resistance and not depression. However, the open field test significantly decreased after 15-day social defeat stress exposure. We also evaluated depressive-like behavior using the sucrose preference and social interaction tests. Our data indicate that defeated CGRP Tg mice exhibited a depressive-like phenotype, which was inferred from increased social avoidance and reduced sucrose preference compared with non-defeated controls. Although stress exposure did not change the BDNF levels in CGRP Tg mice, it significantly decreased the expression levels of p-Akt, p-mTOR and p-p70S6K in the mice hippocampi. We conclude that CGRP-overexpressing Tg mice have normal sensitivity to stress and down-regulated hippocampal Akt/mTOR/p70S6K pathways.

Statins for major depressive disorder: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The burden of depressive disorder is large and new treatment approaches are required. Repurposing widely available drugs such as statins may be a time- and cost-effective solution. Statins have anti-inflammatory and anti-oxidant properties which have been shown to be relevant to the pathophysiology of depression. This study assesses the efficacy, acceptability, tolerability, and safety of statins in major depressive disorder.

METHODS

Our study is an update and extension of a previous meta-analysis published in 2016 by Salagre et al. We performed a systematic review (PubMed/MEDLINE, Cochrane CENTRAL, ISI Web of Science, CINAHL, and ClinicalTrials.gov until the 1st September 2020) and meta-analysis of randomized controlled trials using any statin against placebo or any other statin in the treatment of major depressive disorder. Our primary efficacy outcome measure was the mean value on any standardized scale for depressive symptoms at 8 weeks of treatment. We also calculated outcomes for efficacy, response, and remission at 2, 4, and 12 weeks, as well as acceptability (dropouts for any cause), tolerability (dropouts due to any adverse event), and safety (any adverse event) outcomes at the studies' endpoints. Furthermore, we conducted an exploratory network meta-analysis for the primary efficacy outcome to identify potential differences between statins.

RESULTS

We retrieved five randomized controlled trials meeting our inclusion criteria: four used a statin in addition to an antidepressant and compared it to placebo plus antidepressant, and one compared two statins alone. and one comparing one statin with another. Statins compared to placebo in addition to antidepressants were efficacious at 8 weeks (N = 255, SMD = -0.48, 95% CI = -0.74 to -0. 22) and 12 weeks (N = 134, SMD = -0.47, 95% CI = -0.89 to -0.05, moderate certainty) with no difference for acceptability, tolerability, and safety (low certainty). An exploratory network meta-analysis suggested that the most lipophilic statins, especially simvastatin, could be more efficacious than less lipophilic or hydrophilic molecules.

CONCLUSIONS

This systematic review suggests the efficacy, acceptability, tolerability, and safety of statins in addition to antidepressants in patients with major depressive disorder. Further clinical trials in different settings are required to test this result.

TRIAL RGISTRATION

PROSPERO registration: CRD42020170938.

Downregulation of hippocampal SIRT6 activates AKT/CRMP2 signaling and ameliorates chronic stress-induced depression-like behavior in mice

Sirtuin 6 (SIRT6) has been reported to play a key role in cognitive function and mood regulation, yet its role in mood disorders is not completely understood. Here, we confirmed that knockdown of hippocampal SIRT6 alleviated depression-like behaviors induced by chronic unpredictable stress (CUS) in mice. Our in vitro data showed that SIRT6 negatively regulated protein kinase B (AKT) signaling by deacetylating histone 3 at Lys9 and Lys56. Knockdown of SIRT6 significantly increased AKT phosphorylation activity, while decreased collapsin response mediator protein 2 (CRMP2) phosphorylation activity. Furthermore, pharmacologic inhibition of SIRT6 by ferulic acid (FA) (40 or 80 mg· kg^-1 per day, i.g.) could activate AKT/CRMP2 pathway in vitro, which has been proved to exert an antidepressant-like effect on CUS-induced depressive models. In conclusion, our study suggested that hippocampal SIRT6 contributes to the performance of depression-like behaviors by suppressing AKT/CRMP2 signaling, and FA ameliorates CUS-induced depression-like behaviors in mice as a potential pharmacologic inhibitor of SIRT6.

Involvement of agmatine in antidepressant-like effect of HMG-CoA reductase inhibitors in mice

3-Hydroxy-3-methyl-glutaryl-co-enzyme-A (HMG-CoA) reductase inhibitors (statins) are popularly used for the treatment of obesity and hypercholesterolemia with established safety profile. Statins exhibits a wide range of neurobehavioral effects in addition to their peripheral actions, and may be beneficial in treatment of psychiatric conditions. Present study investigated the role of agmatine and imidazoline receptors in antidepressant-like effect of statins in mouse forced swimming test (FST). The antidepressant-like effect of atorvastatin (5 mg/kg, p.o.) and simvastatin (10 mg/kg, p.o.) was potentiated by pretreatment with agmatine (5 mg/kg, i.p.) as well as the drugs known to increase endogenous agmatine levels in brain viz., L-arginine (40 μg/mouse, i.c.v.), an agmatine biosynthetic precursor; arcaine (50 μg/mouse, i.c.v), agmatinase inhibitor; and aminoguanidine (6.5 μg/mouse, i.c.v.), a diamine oxidase inhibitor. Further, both the statins increased agmatine levels within hippocampus and prefrontal cortex. Conversely, prior administration of I₁ receptor antagonist, efaroxan (1 mg/kg, i.p.) and I₂ receptor antagonist, idazoxan (0.25 mg/kg, i.p.) blocked the antidepressant-like effect of statins and their synergistic combination with agmatine. These results demonstrate the involvement of agmatine and imidazoline receptors in antidepressant-like effect of statins and suggest as a potential therapeutic target for the treatment of depressive disorders.

Molecular and biological functions of resveratrol in psychiatric disorders: a review of recent evidence

Mental disorders including depression, anxiety, schizophrenia, autism spectrum disorders, bipolar and etc. have a considerable proportion of global disorder burden. Many nutritional psychiatry investigations have been conducted to evaluate the relationship between several individual nutrients such as herbal compounds with mental health. Resveratrol, a famous polyphenol compound, is known as an antioxidant, anti-inflammatory, anti-apoptotic, and neuroprotective agent regulating the function of brain and improves the behavioral factors associated with learning, anxiety, depression, and memory. In addition, this natural compound can cross the blood–brain barrier representing neurological influences. The pharmacological interest of utilizing resveratrol in mental disorders is due to its anti-inflammatory and antioxidant features. The aim of this paper was to review the studies evaluated the potential effects of resveratrol on mental disorders.

Propofol exerts neuroprotective functions by down-regulating microRNA-19a in glutamic acid-induced PC12 cells

BACKGROUND

Propofol, a kind of intravenous sedative drug, is certified that exerts anti-inflammation and antitumor functions. However, the influence of propofol in cerebral injury and the corresponding mechanism remains unexplained, that our article focuses on.

METHODS

PC12 cells were treated with propofol and exposed in glutamic acid (Glu) solutions. Cell viability, apoptotic potential, apoptosis-related and autophagy-linked proteins were tested via CCK-8, flow cytometry, and western blot assays. Reverse transcription-quantitative real-time PCR was utilized to test miR-19a expression in Glu-stimulated cells. Next, miR-19a mimic transfection was used to assess the effects of miR-19a on cell apoptosis and autophagy in Glu or propofol treated cells. Finally, western blot was performed to test AMPK and mTOR pathways.

RESULTS

Glu exposure promoted cell apoptosis and autophagy of PC12 cells, while propofol attenuated cell apoptosis and autophagy triggered by Glu. Additionally, propofol decreased the miR-19a expression in Glu-stimulated PC12 cells. Meanwhile, over-expression of miR-19a reversed the effects of propofol on Glu-induced cell apoptosis and autophagy. Moreover, propofol potentiated AMPK and mTOR pathways in Glu-stimulated PC12 cells via impeding miR-19a expression.

CONCLUSIONS

These finding revealed that propofol relieved Glu-triggered apoptosis and autophagy of PC12, and activated AMPK and mTOR pathways by suppressing miR-19a expression.

Dual-specificity phosphatases in mental and neurological disorders

The dual-specificity phosphatase (DUSP) family includes a heterogeneous group of protein phosphatases that dephosphorylate both phospho-tyrosine and phospho-serine/phospho-threonine residues within a single substrate. These protein phosphatases have many substrates and modulate diverse neural functions, such as neurogenesis, differentiation, and apoptosis. DUSP genes have furthermore been associated with mental disorders such as depression and neurological disorders such as Alzheimer's disease. Herein, we review the current literature on the DUSP family of genes concerning mental and neurological disorders. This review i) outlines the structure and general functions of DUSP genes, and ii) overviews the literature on DUSP genes concerning mental and neurological disorders, including model systems, while furthermore providing perspectives for future research.

Long-term metformin therapy improves neurobehavioral functions and antioxidative activity after cerebral ischemia/reperfusion injury in rats

Metformin (MET),an antidiabetic drug, has shown antioxidative and neuroprotective effects. In the present investigation, we aimed to study the probable effects of MET on cerebral ischemia/reperfusion in rats. Rats underwent cerebral ischemia/reperfusion and MET was administered orally at doses of 100 and 200 mg/kg for 56 days. Anxiety- and depressive-like behaviors were evaluated by elevated plus-maze or forced swimming tests, respectively. was assessed by. Cognitive functions were assessed by Y-maze continuous alternation task and morris water maze. The activity of SOD and the level of BDNF were measured in brains samples. Our results showed that administration of 200 mg/kg MET reduced the percent of brain edema (84.00 ± 2.13) in comparison with the ischemic animals (91.25 ± 2.25) (p < 0.05). Administration of 200 mg/kg MET in ischemic animals improved anxiety-like behavior by increasing the percentage of the open arms entries (46.51 ± 3.13) and the percentage of the open arms time (32.70 ± 2.49) in comparison with the cerebral ischemia group (26.35 ± 7.02 and 15.32 ± 5.78, respectively) (all p < 0.001). MET treatment (200 mg/kg) increased the cognition index of correct alternations (90.20 ± 4.95) in comparison with the cerebral ischemia group (59.50 ± 8.01) (p < 0.05). MET at the both doses reduced escape latency compared to the cerebral ischemia animals (all p < 0.05). In addition, 200 mg/kg MET increased the time spent in the target quadrant (16.06 ± 0.58) in comparison with the ischemic animals (9.84 ± 0.92) (p < 0.001) and the both doses of the drug increased the number of crossing (5.42 ± 0.36 and 6.5 ± 0.42, respectively) compared to the cerebral ischemia group (3.75 ± 0.31) (p < 0.05 and p < 0.001, respectively). Moreover, 200 mg/kg MET reduced the immobility time (47.50 ± 9.00) in comparison with the cerebral ischemia group (93.43 ± 8.28) (p < 0.001). Furthermore, the both doses of MET increased the BDNF levels (4590 ± 197.6 and 4767 ± 44.10, respectively) in comparison with the ischemic animals (3807 ± 42.56) (p < 0.01 and p < 0.001, respectively). Also, the both doses of the drug increased the SOD activity of brain (52.67 ± 0.33 and 55.00 ± 0.57, respectively) compared to the ischemic animals (49.33 ± 0.33) (p < 0.01 and p < 0.001, respectively). Based on our data, long-term MET therapy may improve behavioral disorders following cerebral ischemia/reperfusion and can be considered as a novel therapeutic approach for the treatment of brain ischemic conditions.

An Integrated Pharmacology-Based Analysis for Antidepressant Mechanism of Chinese Herbal Formula Xiao-Yao-San

Clinical studies and basic science experiments have widely demonstrated the antidepressant and anxiolytic effects of the herbal formula Xiao-Yao-San (XYS). However, the system mechanism of these effects has not been fully characterized. The present study conducted a comprehensive network pharmacological analysis of XYS and sorted all pharmacologically active components (149) through the TCMSP webserver. Then, all potential molecular targets (449) were predicted, of which there were 99 genes clearly related to depression. To further investigate the mechanism of antidepressant effects of XYS, a compound-depression targets (C-DTs) network was constructed, and Gene Ontology (GO) functional and KEGG pathway enrichment analyses were performed for the 99 targets. Enrichment results revealed that XYS could regulate multiple aspects of depression through these targets, related to metabolism, neuroendocrine function, and neuroimmunity. Prediction and analysis of protein–protein interactions resulted in selection of three hub genes (AKT1, TP53, and VEGFA). In addition, a total of seven ingredients from XYS could act on these hub genes and they were identified through ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS), including paeoniflorin, quercetin, luteolin, acacetin, aloe-emodin, Glyasperin C, kaempferol. Hereafter, we investigated the effects of paeoniflorin and its predicted target, the results suggest that it can reverse the neurotoxicity produced by CORT and could be a neuroprotective effect by promoting the phosphorylation of Akt. Overall, our research revealed the complicated antidepressant mechanism of XYS, and also provided a rational strategy for revealing the complex composition and function of Chinese herbal formula.

The antidepressant-like effects of fluvoxamine in mice involve the mTOR signaling in the hippocampus and prefrontal cortex

Recent studies have suggested that activation of the mammalian target of rapamycin (mTOR) signaling may be related to antidepressant actions. Although thought as a selective serotonin reuptake inhibitor (SSRI), the antidepressant mechanisms of fluvoxamine remain elusive. Therefore, this study aims to evaluate whether mTOR underlies the antidepressant-like effects of fluvoxamine. Male C57BL/6 J mice were subjected to 8 weeks of chronic unpredictable mild stress (CUMS) with fluvoxamine administered during the last 2 weeks. Western blotting analyses were then used to assess the expression of the mTOR signaling cascade in the hippocampus and prefrontal cortex (PFC) among all groups. The selective inhibitor of mTOR, rapamycin, was further used. It was found that fluvoxamine treatment fully reversed the effects of CUMS on the mTOR signaling in the hippocampus and PFC, and the usage of rapamycin significantly prevented the antidepressant-like effects of fluvoxamine in the CUMS model of depression. Taken together, the mTOR system is involved in the antidepressant mechanisms of fluvoxamine.

Atorvastatin protects cardiomyocyte from doxorubicin toxicity by modulating survivin expression through FOXO1 inhibition

BACKGROUND

Survivin has an anti-apoptotic effect against anthracycline-induced cardiotoxicity. Clinically, statin use is associated with a lower risk for heart failure in breast cancer patients with anthracycline chemotherapy. So, the purpose of our study was to investigate whether survivin mediates the protective effect of statin against anthracycline-induced cardiotoxicity.

METHODS

Mice were treated once a week with 5 mg/kg doxorubicin for 4 weeks with or without atorvastatin 20 mg/kg every day then heart tissues were analyzed. Molecular and cellular biology analyses were performed with H9c2 cell lysates.

RESULTS

Doxorubicin suppressed survivin expression via activation of FOXO1 in H9c2 cardiomyocytes. Whereas, atorvastatin inhibited FOXO1 by increasing phosphorylation and inhibiting nuclear localization. Doxorubicin induced FOXO1 binding to STAT3 and prevented STAT3 from interacting with Sp1. However, atorvastatin inhibited these interactions and stabilized STAT3/Sp1 transcription complex. Chromatin immunoprecipitation analysis demonstrated that doxorubicin decreased STAT3/Sp1 complex binding to survivin promoter, whereas atorvastatin stabilized this binding. In mouse model, atorvastatin rescued doxorubicin-induced reduction of survivin expression and of heart function measured by cardiac magnetic resonance imaging.

CONCLUSIONS

Our study suggested a new pathophysiologic mechanism that survivin mediated protective effect of atorvastatin against doxorubicin-induced cardiotoxicity via FOXO1/STAT3/Sp1 transcriptional network.

The antidepressant-like effect of guanosine is dependent on GSK-3β inhibition and activation of MAPK/ERK and Nrf2/heme oxygenase-1 signaling pathways

Although guanosine is an endogenous nucleoside that displays antidepressant-like properties in several animal models, the mechanism underlying its antidepressant-like effects is not well characterized. The present study aimed at investigating the involvement of ERK/GSK-3β and Nrf2/HO-1 signaling pathways in the antidepressant-like effect of guanosine in the mouse tail suspension test (TST). The immobility time in the TST was taken as an indicative of antidepressant-like responses and the locomotor activity was assessed in the open-field test. Biochemical analyses were performed by Western blotting in the hippocampus and prefrontal cortex (PFC). The combined treatment with sub-effective doses of guanosine (0.01 mg/kg, p.o.) and lithium chloride (a non-selective GSK-3β inhibitor, 10 mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01 μg/site, i.c.v.) produced a synergistic antidepressant-like effect in the TST. The antidepressant-like effect of guanosine (0.05 mg/kg, p.o.) was completely prevented by the treatment with MEK1/2 inhibitors U0126 (5 μg/site, i.c.v.), PD98059 (5 μg/site, i.c.v.), or zinc protoporphyrin IX (ZnPP) (HO-1 inhibitor, 10 μg/site, i.c.v). Guanosine administration (0.05 mg/kg, p.o.) increased the immunocontent of β-catenin in the nuclear fraction and Nrf2 in the cytosolic fraction in the hippocampus and PFC. The immunocontent of HO-1 was also increased in the hippocampus and PFC. Altogether, the results provide evidence that the antidepressant-like effect of guanosine in the TST involves the inhibition of GSK-3β, as well as activation of MAPK/ERK and Nrf2/HO-1 signaling pathways, highlighting the relevance of these molecular targets for antidepressant responses.

MicroRNAs expressed in depression and their associated pathways: A systematic review and a bioinformatics analysis

Depression is a debilitating mental illness, one of the most prevalent worldwide. MicroRNAs have been studied to better understand the biological mechanisms that regulate this disease. This study review systematically the literature to identify which microRNAs are currently being associated with depression and their related pathways. The electronic search was conducted in PubMed, Scopus, Scielo, ISI Web of Knowledge, and PsycINFO databases, using the search terms "Depressive Disorder" or "Depression" and "MicroRNAs". After, microRNAs that were up and down-regulated in depression were analyzed by bioinformatics. We observed that among the 77 microRNAs cited by included studies, 54 had their levels altered in depressed individuals compared to controls, 30 being up-regulated and 24 down-regulated. The bioinformatics analysis revealed that among the up-regulated microRNAs there were 81 total and 43 union pathways, with 15 presenting a significant difference. Among the down-regulated microRNAs, 67 total and 45 union pathways were found, with 14 presenting a significant difference. The miR-17-5p and let-7a-5p were the most frequently found microRNAs in the statistically significant pathways. In this study a panel of altered microRNAs in depression was created with their related pathways, which is a step towards understanding the complex network of microRNAs in depression.

Putative neuroprotective pharmacotherapies to target the staged progression of mental illness

AIM

Neuropsychiatric disorders including depression, bipolar and schizophrenia frequently exhibit a neuroprogressive course from prodrome to chronicity. There are a range of agents exhibiting capacity to attenuate biological mechanisms associated with neuroprogression. This review will update the evidence for putative neuroprotective agents including clinical efficacy, mechanisms of action and limitations in current assessment tools, and identify novel agents with neuroprotective potential.

METHOD

Data for this review were sourced from online databases PUBMED, Embase and Web of Science. Only data published since 2012 were included in this review, no data were excluded based on language or publication origin.

RESULTS

Each of the agents reviewed inhibit one or multiple pathways of neuroprogression including: inflammatory gene expression and cytokine release, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophin dysregulation and apoptotic signalling. Some demonstrate clinical efficacy in preventing neural damage or loss, relapse or cognitive/functional decline. Agents include: the psychotropic medications lithium, second generation antipsychotics and antidepressants; other pharmacological agents such as minocycline, aspirin, cyclooxygenase-2 inhibitors, statins, ketamine and alpha-2-delta ligands; and others such as erythropoietin, oestrogen, leptin, N-acetylcysteine, curcumin, melatonin and ebselen.

CONCLUSIONS

Signals of evidence of clinical neuroprotection are evident for a number of candidate agents. Adjunctive use of multiple agents may present a viable avenue to clinical realization of neuroprotection. Definitive prospective studies of neuroprotection with multimodal assessment tools are required.

Characterization of the Brain Penetrant Neuropeptide Y Y2 Receptor Antagonist SF-11

This paper discusses the biological and three-dimensional molecular structure of the novel, nonpeptide Y2R antagonist, SF-11 [N-(4-ethoxyphenyl)-4-(hydroxydiphenylmethyl)-1-piperidinecarbothioamide]. Pharmacokinetic studies in a rat model indicated that, following intraperitoneal dosing, SF-11 crossed the blood-brain barrier and was able to penetrate the brain, making it a suitable tool for behavioral studies. We showed for the first time that SF-11 decreased the immobility time in the forced swim test (FST) after acute peripheral administration (10 and 20 mg/kg), indicating that it has antidepressant potential. Inhibitors of the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways blocked the anti-immobility effect of SF-11, suggesting that these pathways are involved in the antidepressant-like activity of SF-11 in the FST. The results of locomotor activity of rats indicate that the effects observed in the FST are specific and due to the antidepressant-like activity of SF-11. These findings provide further evidence for the antidepressant potential of Y2R antagonists. Also, the application of Fourier transform infrared absorption (FT-IR) and Raman spectroscopy (RS) methods combined with theoretical density functional theory (DFT) calculations allowed us to present the optimized spatial orientation of the investigated drug. Structural characterization of SF-11 based on vibrational spectroscopic data is of great importance and will aid in understanding its biological activity and pave the way for its development as a new antidepressant agent.

Antidepressant drug-protein interactions studied by spectroscopic methods based on fluorescent carbon quantum dots

A highly sensitive fluorescent carbon quantum dots (CDs) was designed to measure the interaction of antidepressant drugs and serum albumins (SA). In present investigation the interaction of bovine serum albumin (BSA) and human serum albumin (HSA) with antidepressant drugs viz. amitryptiline hydrochloride (AMT), chlorpromazine hydrochloride (CPZ) and desipramine hydrochloride (DSP) bioconjugated on CDs have been studied by different spectroscopic techniques i.e., Fluorescence, UV-Visible, Dynamic light scattering (DLS) and FT-IR. The CDs were prepared by one-pot method using glucose and PEG-200. The developed CDs showed blue luminescence under irradiation with ultra-violet. The Stern-Volmer quenching constant (K sv ) indicates the presence of static quenching mechanism. The apparent binding constant K a between antidepressant drugs with complex of SA-CDs have been determined. These results illustrated that CPZ shows strong binding with HSA. As further analyzed by FT-IR spectroscopy and DLS technique, the results suggested induced conformational changes on SA, thus confirming the experimental and theoretical results. Thus, a thorough knowledge of the energetics of drug-protein affinities in presence of CDs as attempted in this work is vital in giving way for appropriate drug delivery.

Antidepressive effects of kaempferol mediated by reduction of oxidative stress, proinflammatory cytokines and up-regulation of AKT/β-catenin cascade

Kaempferol (KFL), the major constituent of various fruits and vegetables, could attenuate oxidaitve stress and inflammation. The aims of the present study were to explore the ameliorative abilities of KFL on the depressive-like behaviors in a chronic social defeat stress (CSDS) mouse model, and to determine the potential mechanisms on oxidative stress, neuroinflammation, and AKT/β-catenin signaling pathway. Three behavioral tests, sucrose preference test (SPT), social interaction test (SIT), and tail suspension test (TST), were used to evaluate the antidepressive effects of KFL in CSDS mice. Activity levels of antioxidant enzyme, superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione s-transferase (GST), and concentrations of malonaldehyde (MDA) and protein carbonylation in the prefrontal cortex were assessed by commercial kits, respectively. Elisa was used to detect the levels of interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α). Q-PCR was used to determine the mRNA level of CD-11b. Furthermore, activity level of AKT/β-catenin signaling in the prefrontal cortex of CSDS mice was investigated by western blot. In addition, LY294002, a PI3-K inhibitor, was used to investigate the role of AKT/β-catenin signaling in the antidepressant effects of KFL. Social defeat stress reduced the bodyweights, sucrose consumptions, social interaction times, and the tail suspension mobility times in mice. CSDS mice were also exhibited remarkablely increased levels in oxidative stress markers, inflammatory mediators, and decreased activity of AKT/β-catenin cascade in the prefrontal cortex, which were reversed by treatment with KFL. Interestingly, LY294002 appeared to partly inhibit the overall KFL-mediated protective effects in the CSDS mice. These results confirmed that KFL exerted antidepressive effects, which might be mediated, at least in part, by enhanced antioxidant abilities and anti-inflammation effects via up-regulation AKT/β-catenin cascade activity in the prefrontal cortex of CSDS mice. Thus, KFL might be a promising, effective, and safe food medicine for depression treatment.

Resveratrol exerts a protective effect in chronic unpredictable mild stress-induced depressive-like behavior: involvement of the AKT/GSK3β signaling pathway in hippocampus

BACKGROUND

Chronic unpredictable mild stress (CUMS) is an important contributing factor for depression with inflammatory response alteration, neuron apoptosis, and decreased neurogenesis. Previous study reported that the administration of resveratrol alleviated depression by normalizing the increased proinflammatory cytokine levels and inhibiting apoptosis in the hippocampus. However, the upstream signaling pathway that regulates cytokines and apoptosis in the antidepressant effect of resveratrol remains unclear.

OBJECTIVE

The objective of this study is to investigate the possible mechanism of the effect of resveratrol on depression.

METHODS

Male Sprague Dawley rats were exposed to CUMS for four consecutive weeks to elicit depressive-like behavior. The rats in the drug treatment groups were injected with resveratrol (40 or 80 mg/kg/day) and fluoxetine (10 mg/kg/day) intraperitoneally for 4 weeks. Rats in two additional groups were administered LY294002 by bilateral stereotaxic microinjection into the lateral ventricle before resveratrol administration. Behavioral tests, including sucrose preference test, forced swim test, and open field test, were used after 4 weeks of a CUMS procedure to appraise depressive-like behavior. Then, the proinflammatory cytokines (TNF-α, IL-6, and IL-1β) in the hippocampus and prefrontal cortex (PFC) tissues of rats were measured. Apoptosis-related molecules such as Bax and Bcl-2 mRNA levels in the hippocampus were analyzed. Furthermore, p-Akt/Akt and p-GSK3β/GSK3β protein expression in the hippocampus were also measured.

RESULTS

The results show that rats were subjected to CUMS procedure exhibited depressive-like behavior, increased TNF-α, IL-6, and IL-1β levels in hippocampus and PFC, alteration of Bax and Bcl-2 mRNA levels in hippocampus, decreased p-Akt/Akt and p-GSK3β/GSK3β protein expression in hippocampus, and an increased apoptotic cell percentage in the hippocampal CA1 region. However, resveratrol (40 or 80 mg/kg) treatment reversed these behavioral and molecular changes in CUMS rats. The positive control drug fluoxetine showed a similar effect as the resveratrol treatment. When rats were injected with LY294002 before resveratrol treatment, the antidepressant effect of resveratrol was significantly attenuated, TNF-α, IL-6 and IL-1β levels in hippocampus and PFC increased again, Bax mRNA levels increased and Bcl-2 mRNA levels decreased in hippocampus, and Akt/GSK3β protein expression in hippocampus decreased.

CONCLUSIONS

The findings in the present study suggest that the antidepressant effect of resveratrol treatment may act through activation of the Akt/GSK3β signaling pathway and then regulation of proinflammatory cytokine expression and alteration of apoptosis.

Atorvastatin prevents lipopolysaccharide-induced depressive-like behaviour in mice

Clinical and pre-clinical evidences indicate an association between inflammation and depression since increased levels of pro-inflammatory cytokines are associated with depression-related symptoms. Atorvastatin is a cholesterol-lowering statin that possesses pleiotropic effects including neuroprotective and antidepressant actions. However, the putative neuroprotective effect of atorvastatin treatment in the acute inflammation mice model of depressive-like behaviour has not been investigated. In the present study, we aimed to investigate the effect of atorvastatin treatment on lipopolysaccharide (LPS) induced depressive-like behaviour in mice. Mice were treated with atorvastatin (1 or 10 mg/kg, v.o.) or fluoxetine (30 mg/kg, positive control, v.o.) for 7 days before LPS (0.5 mg/kg, i.p.) injection. Twenty four hours after LPS infusion, mice were submitted to the forced swim test, tail suspension test or open field test. After the behavioural tests, mice were sacrificed and the levels of tumour necrosis factor-α (TNF-α), brain-derived neurotrophic factor (BDNF), glutathione and malondialdehyde were measured. Atorvastatin (1 or 10 mg/kg/day) or fluoxetine treatment prevented LPS-induced increase in the immobility time in the forced swim and tail suspension tests with no alterations in the locomotor activity evaluated in the open field test. Atorvastatin (1 or 10 mg/kg/day) or fluoxetine treatment also prevented LPS-induced increase in TNF-α and reduction of BDNF levels in the hippocampus and prefrontal cortex. Treatment with atorvastatin (1 or 10 mg/kg/day) or fluoxetine prevented LPS-induced increase in lipid peroxidation and the reduction of glutathione levels in the hippocampus and prefrontal cortex. The present study suggests that atorvastatin treatment exerted neuroprotective effects against LPS-induced depressive-like behaviour which may be related to reduction of TNF-α release, oxidative stress and modulation of BDNF expression.

Centrally Administered Cortistation-14 Induces Antidepressant-Like Effects in Mice via Mediating Ghrelin and GABAA Receptor Signaling Pathway

Cortistatin-14 (CST-14), a recently discovered cyclic neuropeptide, can bind to all five cloned somatostatin receptors (SSTRs) and ghrelin receptor to exert its biological activities and co-exists with GABA within the cortex and hippocampus. However, the role of CST-14 in the control of depression processes is not still clarified. Here, we tested the behavioral effects of CST-14 in the in a variety of classical rodent models of depression [forced swimming test (FST), tail suspension test (TST) and novelty-suppressed feeding test]. In the models of depression, CST-14 produced antidepressant-like effects, and does not altered locomotor activity levels. And, we found that CST-14 mRNA and BDNF mRNA were significantly decreased in the hippocampus and cortex after mice exposed to stress. Further data show that i.c.v. administration of CST-14 produce rapid antidepressant effects, and does not altered locomotor activity levels. Then these antidepressant-like effects were significantly reversed by [D-Lys₃]GHRP-6 (ghrelin receptor antagonist), but not c-SOM (SSTRs antagonist). Meanwhile, the effects of some neurotransmitter blockers indicates that only GABA_A system, but not CRF1 receptor, α/β-adrenergic receptor, is involved in the antidepressant effect of CST-14. The effects of the mTOR inhibitor (rapamycin), the PI3K inhibitor (LY294002) and the p-ERK1/2 inhibitor (U0126) suggesting that the ERK/mTOR or PI3K/Akt/mTOR signaling pathway is not involved in the antidepressant effects of CST-14. Interestingly, intranasal administration of CST-14 led to reducing depressive-like behavior, and near-infrared fluorescent experiments showed the real-time in vivo bio-distribution in brain after intranasal infusion of Cy7.5-CST-14. Taken all together, the results of present study point to a role for CST-14 in the modulation of depression processes via the ghrelin and GABA_A receptor, and suggest cortistation may represent a novel strategy for the treatment of depression disorders.

Highlights:-

CST-14 and BDNF mRNA are decreased in hippocampus and cortex once mice exposed to stress.

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i.c.v. or intranasal administration of CST-14 produce rapid antidepressant effects.

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NIR fluorescence imaging detected the brain uptake and distribution after intranasal CST-14.

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Antidepressant effects of CST-14 were only related to ghrelin and GABA_A system.

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Co-injection of CST-14 and NPS produce antidepressant effect, and do not impair memory.

miR-1224-5p Enhances Hepatic Lipogenesis by Targeting Adenosine Monophosphate-Activated Protein Kinase α1 in Male Mice

MicroRNAs are potential therapeutic targets for metabolic diseases. Here, miR-1224-5p was highly expressed in the livers of mice fed a high-fat diet (HFD) and in obese (ob/ob) mice. To examine the potential role of miR-1224-5p, we constructed liver-specific adenoviral vectors expressing either an miR-1224-5p inhibitor sequence or miR-1224-5p mimic sequences. After tail-vein vector injection, HFD-fed mice were examined for expression of lipogenic genes. We found that miR-1224-5p inhibitors significantly attenuated hepatic lipogenesis and steatosis in HFD-fed mice, whereas miR-1224-5p mimicked promoted lipid accumulation in the liver of chow-fed C57BL/6 mice. Additional in vitro studies demonstrated that downregulation of miR-1224-5p in HepG2 and primary hepatocytes led to a reduction of cellular triglycerides after treatment with an oleic acid and palmitic acid mixture. Importantly, this study also identified adenosine monophosphate-activated protein kinase (AMPK)-α1 as a direct target of miR-1224-5p. miR-1224-5p binding to the 3' untranslated region of AMPKα1 suppressed expression of the AMPKα1 protein and its downstream molecules. Metformin, an activator of AMPK, also inhibited hepatic expression of miR-1224-5p. Together, these findings indicate that miR-1224-5p promotes hepatic lipogenesis by suppressing AMPKα1 expression and suggest that miR-1224-5p inhibitors warrant further investigation as potential therapeutic tools in the treatment of nonalcoholic fatty liver disease.

Matrine Exerts Antidepressant-Like Effects on Mice: Role of the Hippocampal PI3K/Akt/mTOR Signaling

BACKGROUND

Current antidepressants in clinical use always take weeks or even months to exert full therapeutic effects, and sometimes have serious side effects. Thus, it is very necessary to develop novel antidepressants with better efficacy and fewer adverse effects. The present study focused on investigating the antidepressant potential of matrine and its possible mechanisms of action.

METHODS

The forced swim test, tail suspension test, and chronic unpredictable mild stress model of depression were used to reveal the antidepressant-like effects of matrine on mice. Western blotting, immunohistochemistry, and lentivirus were further used together to explore the antidepressant mechanism of matrine.

RESULTS

It was found that matrine exhibited significant antidepressant actions in the forced swim test and tail suspension test without affecting the locomotor activity of mice. Chronic matrine administration fully reversed the chronic unpredictable mild stress-induced depressive-like symptoms in forced swim test, tail suspension test, and sucrose preference test. After that, western blotting analysis revealed that chronic matrine treatment restored the decreasing effects of chronic unpredictable mild stress on the PI3K/Akt/mammalian target of rapamycin signaling in hippocampus, but not prefrontal cortex. Furthermore, pharmacological and genetic blockade of the PI3K/Akt/mammalian target of rapamycin signaling in hippocampus abolished the antidepressant actions of matrine on mice.

CONCLUSIONS

Taken together, matrine produces antidepressant-like effects on mice via promoting the hippocampal PI3K/Akt/ mammalian target of rapamycin signaling.

Swimming exercise reverses CUMS-induced changes in depression-like behaviors and hippocampal plasticity-related proteins

BACKGROUND

Stress-induced failed resilience of brain plasticity can contribute to the onset and recurrence of depression. Chronic stress has been reported to open windows of epigenetic plasticity in hippocampus. However, how hippocampal plasticity underlies depression-like behaviors and how it adapts in response to stress has not been addressed. The present study aimed to investigate the signaling mechanisms of CUMS affecting hippocampal plasticity-related proteins expression and the regulation of swimming exercise in mice.

METHODS

Male C57BL/6 mice were subjected to chronic unpredictable mild stress (CUMS) for 7 weeks. From the 4th week, CUMS mice were trained in a moderate swimming program for a total of 4 weeks. A videocomputerized tracking system was used to record behaviors of animals for a 5-min session. Real-time PCR and Western Blotting were used to examine gene expression in mouse hippocampus.

RESULTS

Our results demonstrated that CUMS induced depression-like behaviors, which were reversed by swimming exercise. Moreover, the behavioral changes induced by CUMS and exercise were correlated with hippocampal plasticity-related proteins expression of growth-associated protein-43 (GAP-43) and synaptophysin (SYN). The molecular mechanisms regulating this plasticity may include SIRT1/mircoRNA, CREB/BDNF, and AKT/GSK-3β signaling pathways.

LIMITATIONS

We did not establish a correlation between depression-like behaviors induced by chronic stress and epigenetic changes of hippocampal plasticity, either a causal molecular signaling underling this plasticity.

CONCLUSIONS

Our findings have identified swimming exercise effects on CUMS-induced changes in depression-like behaviors and hippocampal plasticity-related proteins, which provide a framework for developing new strategies to treat stress-induced depression.

Mechanisms and Therapeutic Targets of Depression After Intracerebral Hemorrhage

The relationship between depression and intracerebral hemorrhage (ICH) is complicated. One of the most common neuropsychiatric comorbidities of hemorrhagic stroke is Post-ICH depression. Depression, as a neuropsychiatric symptom, also negatively impacts the outcome of ICH by enhancing morbidity, disability, and mortality. However, the ICH outcome can be improved by antidepressants such as the frequently-used selective serotonin reuptake inhibitors. This review therefore presents the mechanisms of post-ICH depression, we grouped the mechanisms according to inflammation, oxidative stress (OS), apoptosis and autophagy, and explained them through their several associated signaling pathways. Inflammation is mainly related to Toll-like receptors (TLRs), the NF-kB mediated signal pathway, the PPAR-γ-dependent pathway, as well as other signaling pathways. OS is associated to nuclear factor erythroid-2 related factor 2 (Nrf2), the PI3K/Akt pathway and the MAPK/P38 pathway. Moreover, autophagy is associated with the mTOR signaling cascade and the NF-kB mediated signal pathway, while apoptosis is correlated with the death receptor-mediated apoptosis pathway, mitochondrial apoptosis pathway, caspase-independent pathways and others. Furthermore, we found that neuroinflammation, oxidative stress, autophagy, and apoptosis experience interactions with one another. Additionally, it may provide several potential therapeutic targets for patients that might suffer from depression after ICH.

Serotonin transporter immunoreactivity is modulated during development and after fluoxetine treatment in the rodent visual system

The serotonin transporter (5-HTT) regulates serotonin homeostasis and has been used as a target for different drugs in depression treatment. Although the serotonergic system has received a lot of attention, little is known about the effects of these drugs over serotonin transporters. In this work, we investigated the expression pattern of 5-HTT during development of the visual system and the influence of fluoxetine on different signaling pathways. Our data showed that the expression of 5-HTT has a gradual increase from postnatal day 0 until 42 and decrease afterwards. Moreover, chronic fluoxetine treatment both in childhood and adolescence induces down regulation of 5-HTT expression and phosphorylation of ERK and AKT signaling pathways. Together these data suggest that the levels of 5-HTT protein could be important for the development of the central nervous system and suggest that the ERK and AKT are involved in the molecular pathways of antidepressants drugs, acting in concert to improve serotonergic signaling.