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Piper laetispicum C. DC is one of the Chinese herbal medicines used for alleviating depressive disorders. G11‐5 [3‐(3, 4‐methylenedioxy‐5‐trifluoromethyl phenyl)‐2E‐propenoic acid isobutyl amide] is synthesized based on the chemical structure of an active integrant of Piper laetispicum C. DC. The present study assessed the antidepressant effect of G11‐5 and investigated the underlying mechanism with learned helplessness (LH) and social defeat stress (SDS) mice model of depression. In the LH model, mice were exposed to 60 inescapable electric shocks once a day for three consecutive days followed by 2‐week drug administration and helpless behaviour assessment. In the SDS model, mice were subjected to repeated social defeat by an aggressive CD‐1 mouse once a day for consecutive 10 days. Following oral administration for 2 weeks, the mice were subjected to a series of behavioural tests including social interaction test. G11‐5 significantly decreased the number of escape failures induced by LH paradigm, meanwhile increased the social interaction ratio and shortened the immobility time in forced swimming test for the SDS‐exposed mice, suggesting remarkable antidepressant effect. Moreover, G11‐5 ameliorated the changes in mitophagy‐related proteins induced by two stress exposures and restored retrograde axonal transport and neurotransmitter release. Our findings suggested that G11‐5 exhibited an obvious antidepressant through TSPO‐mediated mitophagy pathway. [ABSTRACT FROM AUTHOR]

Abstract: The etiology and pathophysiology of depression remain unknown. Previous works were mostly performed on single observation time-point which might be insufficiently to reveal the molecular events changed during the disease development. Adult BALB/c mice were exposed to unpredictable chronic mild stress (UCMS) for different periods and differential 2D gel electrophoresis (DIGE) approach was employed to the brain tissue to explore the molecular disease signatures. Sustained elevation of corticosterone level was observed, suggesting the hyperactivity of hypothalamic–pituitary–adrenal (HPA) axis when the mice were subjected to the stressful situation. The behavioral results indicated the depressive alterations of the mice exposing to UCMS. The altered proteins identified by proteomics showed that abnormal energy mobilization under stress condition was accompanied by overproduction of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. Cytoskeleton protein and anti-oxidant enzymes were also changed by UCMS treatment. The results of biochemical and immunohistochemical assay confirmed the changes identified by DIGE analysis. These results indicated that the insufficiency of ATP synthesis, overwhelming ROS production and ER stress subsequently contributed to the cytoskeletal damage and inhibition to expression of some anti-oxidant proteins, which might ultimately bring functional neuron to apoptosis or death. Proteins whose expression is affected may provide tools for potential treatment strategies. [Copyright &y& Elsevier]

Low response rate was witnessed with the present monoaminergic based antidepressants, urging a need for new therapeutic target identification. Accumulated evidences strongly suggest that mitochondrial deficit is implicated in major depression and 18 kDa translocator protein (TSPO) plays an important role in regulating mitochondrial function. However the changes of TSPO and TSPO mediated mitophagy pathway in the depressive brain is unclear. In present study, a well validated animal model of depression, learned helplessness (LH), was employed to investigate the relevant changes. Significant behavioral changes were observed in the LH mice. Results showed that TSPO and other mitophagy related proteins, such as VDAC1, Pink1 and Beclin1 were significantly decreased by LH challenge. Moreover, KIFC2, relevant to the mitochondrial transport and Snap25, relevant to neurotransmitter vesicle release, were also obviously down-regulated in the LH mice, which further rendered supportive evidence for the existing mitochondrial dysfunction in LH mice. Present results demonstrated that LH induced depressive symptoms and affected TSPO-mediated mitophagy pathway, indicating a potential target candidate for depression treatment. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Wuling powder (trade name: Wuling capsule), a traditional Chinese medicine (TCM), was extracted from mycelia of precious Xylaria Nigripes (Kl.) Sacc by modern fermentation technology, and has been claimed to be fully potent in improving the signs of insomnia and cognitive deficits. Moreover, Wuling capsule was effective in treating post-stroke and orther co-cormbid depression both in clinical and in basic research. In order to clarify the molecular mechanisms of the antidepressant effect of Wuling powder, we established learned helplessness (LH) depression animal model and focused on 18 kDa translocator protein (TSPO) mediated-mitophagy pathway. Materials and methods Mice were exposed to the inescapable e-shock (IS) once a day for three consecutive days to establish the LH model. Then mice were orally administered Wuling powder for 2 weeks. For the behavioral assessment, Shuttle box test, novelty suppressed feeding test (NSF) and forced swimming test (FST) were performed. Following the behavioral assessment, we assessed the protein expression level that were related to TSPO-mediated mitophagy signaling pathway by Western blotting analysis. Finally, immunohistochemistry method was used to assess the neuroprotective effects of Wuling powder. Results Compared with mice that were subjected to inescapable e-shock, Wuling powder exhibited antidepressant effect in the multiple behavioral tests. In addition, Wuling powder altered the expression level of multiple proteins related to TSPO-mediated mitophagy signaling pathway. Conclusions Our results suggested that Wuling powder exhibited an obvious antidepressant effect, which could be due to the improvement of TSPO-mediated mitophagy signaling pathway. [ABSTRACT FROM AUTHOR]

Most current pharmacologic antidepressant treatments target monoaminergic systems confronts some problems such as low rate of remission and high risk for relapse indicating new therapeutic strategy is urgently need. Evidences showed that impairments in mitochondrial function were associated with the pathogenesis of mood disorders and improvement in its function may be a novel therapeutic choice. In the present study, effects of 5-(4-hydroxy-3-dimethoxybenzylidene)-2-thioxo-4-thiazolidinone (RD-1) were investigated in mice model of depression/anxiety induced by corticosterone (20 mg/kg) subcutaneously repeated injections in 5-week male BALB/c mice. Our results showed that five weeks of corticosterone administration induced anxiety/depressive-like behavioral changes, including decreased central activities in open field test, increased the immobility time in forced swimming test and the latency in the novelty-suppressed feeding test, as well as reduced bodyweight. Results showed that oral administration with RD-1 at the doses of 25, 50, and 100 mg/kg for five weeks significantly improved the anxiety/depressive-like behavioral changes induced by corticosterone. In glucose metabolism analysis by photon emission computed tomography/-computed tomography (PET/CT) imaging, corticosterone significantly deactivated the prefrontal cortex (PFC), temporal lobe and hippocampus. RD-1 treatment obviously improved the energy metabolism in the involved brain regions. In primary cultured hippocampal neuron, corticosterone reduced speed of anterograde transport, yet speed of retrograde transport was increased. Furthermore, RD-1 enhanced the mitochondrial anterograde transport to supply energy for the neurotransmitter release. In conclusion, RD-1 prevents anxiety/depressive-like behavior of mice induced by corticosterone repeated injections with novel mechanism of improvement in the mitochondrial function. [ABSTRACT FROM AUTHOR]