Regulation of Life Extension Factor Klotho on Depressive-like Behaviors via Modulation of GluN2B Function in the Nucleus Accumbens

Klotho is a life extension factor that has an ability to regulate the function of GluN2B-containing N-methyl-D-aspartate receptors (NMDARs), whose dysfunction in the nucleus accumbens (NAc) underlies critical aspects of the pathophysiology of major depression. Here we study the functional relevance of klotho in the pathogenesis of depression. A chronic social defeat stress paradigm, where mice are either categorized as susceptible or unsusceptible group based on their performance in a social interaction test, was used in this study. We found that the expression of klotho was largely decreased in the NAc of susceptible mice when compared to control or unsusceptible group. Genetic knockdown of klotho in the NAc induced depressive-like behaviors in naive mice, while overexpression of klotho produced an antidepressive effect in normal mice and ameliorated the depressive-like behaviors in susceptible mice. Molecularly, knockdown of klotho in the NAc resulted in selective decreases of total and synaptic GluN2B expression that were identical to susceptible mice. Elevation of klotho in the NAc reversed the reductions of GluN2B expressions, as well as altered synaptic transmission and spine density in the NAc of susceptible mice. Furthermore, blockade of GluN2B with a specific antagonist abolished the beneficial effects of klotho elevation in susceptible mice. Collectively, we demonstrated that klotho in the NAc modulates depressive-like behaviors by regulating the function of GluN2B-containing NMDARs. These results reveal a novel role for klotho in the pathogenesis of depression, opening new insights into the molecular basis of major depression.

Antianhedonic Effect of Repeated Ketamine Infusions in Patients With Treatment Resistant Depression

Anhedonia constitutes one of the main symptoms of depressive episode. It correlates with suicidality and significantly effects the quality of patient's lives. Available treatments are not sufficient against this group of symptoms. Ketamine is a novel, rapid acting strategy for treatment resistant depression. Here we report the change in symptoms of anhedonia measured by Snaith-Hamilton Pleasure Scale as an effect of eight ketamine infusions as an add-on treatment in 42 patients with treatment resistant depression. We also determined the effect of this change on the severity of depressive symptoms measured by Inventory for Depression Symptomatology-Self Report 30-Item (IDS-SR 30). We have observed statistically significant decrease in the level of anhedonia during ketamine treatment. After adjusting for potential confounders we have found that significant reduction in Snaith-Hamilton Pleasure Scale (SHAPS) after each infusion and 1 week post treatment was observed only among patients who did not use benzodiazepines. The reduction in symptoms of anhedonia mediates the antidepressive effect of ketamine. The results need replication in a larger randomized placebo controlled trial.

Antidepressive effect of an inward rectifier K+ channel blocker peptide, tertiapin-RQ

Renal outer medullary K+ channel, ROMK (Kir1.1, kcnj1) is expressed in the kidney and brain, but its role in the central nervous system remains unknown. Recent studies suggested an involvement of the ROMK channel in mental diseases. Tertiapin (TPN) is a European honey bee venom peptide and is reported to selectively block the ROMK channel. Here, we have chemically synthesized a series of mutated TPN peptides, including TPN-I8R and -M13Q (TPN-RQ), reported previously, and examined their blocking activity on the ROMK channel. Among 71 peptides tested, TPN-RQ was found to block the ROMK channel most effectively. Whole-cell patch-clamp recordings showed the essential roles of two disulfide bonds and the circular structure for the blockade activity. To examine the central role, we injected TPN-RQ intracerebroventricularly and examined the effects on depression- and anxiety-like behaviors in mice. TPN-RQ showed an antidepressive effect in tail-suspension and forced swim tests. The injection of TPN-RQ also enhanced the anxiety-like behavior in the elevated plus-maze and light/dark box tests and impaired spontaneous motor activities in balance beam and wheel running tests. Administration of TPM-RQ suppressed the anti-c-Fos immunoreactivity in the lateral septum, without affecting immunoreactivity in antidepressant-related nuclei, e.g. the dorsal raphe nucleus and locus coeruleus. TPN-RQ may exert its antidepressive effects through a different mechanism from current drugs.

Antidepressive Effect of Antipsychotics in the Treatment of Schizophrenia: Meta-Regression Analysis of Randomized Placebo-Controlled Trials

Background Antipsychotics improve the positive symptoms of schizophrenia. However, little is known about the extent of antidepressive effects of antipsychotics and their correlation with effects on other symptom domains in schizophrenia. The aim was to investigate whether antidepressive effects of antipsychotics have a significant correlation with the effects on specific symptom domains of schizophrenia. Methods Electronic databases were searched to identify eligible studies that reported antidepressive effects of antipsychotics for the treatment of adult patients with schizophrenia in double-blind, randomized placebo-controlled trials (RCTs). Mean change from baseline in depressive symptoms was meta-analyzed, and the correlation with the effects on other symptom domains was examined through meta-regression analysis. Results Thirty-five RCTs (13 890 patients) were included in this meta-analysis. Overall, antipsychotics showed greater efficacy than placebo in reducing depressive symptoms, with small to medium effect sizes (standardized mean difference = −0.27, 95% confidence interval −0.32 to −0.22, P < .001). All the antipsychotics, except for chlorpromazine, haloperidol, and ziprasidone, were associated with significantly greater decreases in depressive symptoms compared with placebo (standardized mean difference = −0.19 to −0.40). A higher antidepressive effect was significantly correlated with a higher improvement in Positive and Negative Syndrome Scale/Brief Psychiatric Rating Scale total, positive, and negative, and Positive and Negative Syndrome Scale-general psychopathology symptoms (β = .618, P < .001; β = .476, P < .001; β = .689, P < .001; β = .603, P < .001, respectively). Conclusions Second-generation antipsychotics (except for ziprasidone) were associated with small to medium effects sizes on improvement in depressive symptoms among adult patients with schizophrenia. The antidepressive effect of antipsychotics was significantly correlated with improvement in other symptom domains, with the highest correlation observed for improvement in negative symptoms. PROSPERO registration number CRD42019133015

Jieyu Anshen Granule, a Chinese Herbal Formulation, Exerts Effects on Poststroke Depression in Rats

Jieyu Anshen granule (JY) is a traditional Chinese medicine formula for treating depression and anxiety. The aim of the study was to observe the effects of JY on poststroke depression (PSD) and investigate the underlying mechanism. PSD rat model was developed by middle cerebral artery occlusion following chronic unpredictable mild stress in conjunction with isolation rearing. We performed behavioral tests, Western blot, ELISA, and BrdU/NeuN staining. Treatment with JY showed significant antidepressant effect in open-field and sucrose preference tests, as well as significant improvement in beam-walking, cylinder, grip strength, and water maze tests. In addition, treatment with JY could restore the levels of neurotransmitters and decrease the levels of hormone and inflammation cytokines in serum and brain. Treatment with JY also showed significant regulation in the expression of neurotransmitter receptors and NF-κB/IκB-α signaling in the prefrontal cortex and hippocampus. Moreover, the numbers of newborn neurons in the hippocampus were increased by treatment with JY. Our results suggest that JY could ameliorate PSD and improve the neurological and cognitive functions. The antidepressive effect may be associated with the modulation of JY on monoamine system, neuroendocrine, neuroinflammation, and neurogenesis.

Mahuang-Fuzi-Xixin Decoction Reverses Depression-Like Behavior in LPS-Induced Mice by Regulating NLRP3 Inflammasome and Neurogenesis

Evidence suggests that inflammation and neurogenesis play an important role in major depressive disorder (MDD). Mahuang-Fuzi-Xixin decoction (MFX), as the traditional Chinese prescription, has been widely applied for asthma, migraine, and MDD in clinics. However, the effects of MFX on the potential mechanism in MDD are still unclear. Hence, the present study is aimed at exploring whether the antidepressive effect of MFX is connected to the anti-inflammatory and promoting neurogenesis. Besides, lipopolysaccharide (LPS) of Gram-negative bacteria can induce depressive-like behaviors. We demonstrated that administration of MFX corrected the depressive-like behaviors in LPS-induced mice and significantly decreased the expression of IL-1β in the hippocampus. LPS injection induced a significant increase in the levels of NLRP3, cleaved caspase-1 p20, and ASC in the hippocampus, as well as Trx-interacting protein (TXNIP), and MFX could reverse this change. What is more, treatment of MFX increased the level of doublecortin (DCX), brain-derived neurotrophic factor (BDNF), and tropomyosin-related kinase receptor B (TrkB) in the hippocampus which means that MFX could promote the neurogenesis. In conclusion, the study indicates that MFX relieves a depressive-like state in LPS-induced mice through the inhibition of the NLRP3 inflammasome and the enhancement of the neurogenesis pathway.

Differentiated approach and indications for optimization of agomelatine therapy for endogenous depression

Objective: to develop and justify differentiated indications for the use of agomelatine (valdoxan) to treat the typological variants of endogenous depressions with varying severity on the basis of an analysis of its therapeutic efficacy.Patients and methods. An open prospective study was conducted using the clinical, psychopathological, and psychometric rating scales: the Hamilton Depression Rating Scale (HAMD-21); Udvalg for Kliniske Undersњgelser Scale (UKU); the Snaith-Hamilton Pleasure Scale (SHAPS) for assessing anhedonic disorders, and statistical methods. Examinations were made in 56 patients (mean age, 34.9 years) with moderate and severe endogenous depression within affective psychosis (n=42) and shift-like schizophrenia (n=14) (ICD-10 items F31.3–4; F32.1–2, and F33.1–2). The patients received a cycle treatment with agomelatine (valdoxan) 25–50 mg once a day in the evening for 4–8 weeks. The patients' status was evaluated over time on fixed days from a reduction in the mean total score (MTS) of the respective scales as insignificant (less than 19% reduction in disorders), moderate (20–49%), good (50–69%), and excellent (70% or more) effects. The effect of agomelatine was analyzed in two patient groups. The specific features of the antidepressive effect and its dynamics in the presence of endogenous depressions of different typologies (melancholic, anxious, and adynamic depressions) were studied in Group 1 (n=26); the effect of agomelatine on anhedonic endogenous depressions and manifestations of anhedonia in different mental activity areas (interests, social activity, emotional engagement and eating/drinking) was investigated in Group 2 (n=30).Results and discussion. There was a good tolerance and a high antidepressant activity of agomelatine during its treatment cycle for moderate and severe endogenous depressions. A significant improvement (an 84.4% reduction in HAMD-21 MTS) was noted in patients at 3 and 4 weeks of the treatment cycle and consistently persisted at a subsequent follow-up. Agomelatine showed a good effect (a 50% or more reduction in HAMD-21 MTS) just at 14 days of therapy. The drug was observed to have a balanced antidepressant effect, significant thymoleptic, stimulant, anxiolytic, and antianhedonic activities (reductions in the MTS of depressive disorders by 90.83, 84.9, 82.39, and 78.9%, respectively).Conclusion. The universal spectrum of the antidepressive effect of agomelatine, its good tolerability, high efficacy, and rapid improvement makes it the drug of choice in treating a wide range of psychopathological endogenous depressions: melancholic, apatho-adynamic, anxious, and anhedonic ones.