Dual Transneuronal Tracing in the Rat Entorhinal-Hippocampal Circuit by Intracerebral Injection of Recombinant Rabies Virus Vectors

Dual transneuronal tracing is a novel viral tracing methodology which employs two recombinant viruses, each expressing a different reporter protein. Peripheral injection of recombinant pseudorabies viruses has been used as a powerful method to define neurons that coordinate outputs to various peripheral targets of motor and autonomic systems. Here, we assessed the feasibility of recombinants of rabies virus (RV) vector for dual transneuronal tracing in the central nervous system. First, we examined whether two different RV-vectors can double label cells in vitro, and showed that efficient double labeling can be realized by infecting targeted cells with the two RV-vectors within a short time interval. The potential of dual transneuronal tracing was then examined in vivo in the entorhinal-hippocampal circuit, using the chain of projections from CA3 pyramidal cells to CA1 pyramidal cells and subsequently to entorhinal cortex. Six days after the injection of two RV-vectors into the left and right entorhinal cortex respectively, double-labeled neurons were observed in CA3 bilaterally. Some double-labeled neurons showed a Golgi-like labeling. Dual transneuronal tracing potentially provides a powerful and sensitive method to study issues such as the amount of convergence and divergence within and between circuits in the central nervous system. Using this sensitive technique, we established that single neurons in CA3 are connected to the entorhinal cortex bilaterally with only one synaptic relay

Utility of 19-Hydroxycholesterol as an Internal Standard Compound for the Quantitative Determination of Sterols Using Capillary Gas Chromatograph

Gas chromatography is able to detect many kinds of sterols simultaneously. In order to identify and estimate accurately many kinds of sterols in biological samples by gas chromatography, it is indispensable to add an internal standard compound into the analytical samples prior to the analysis. However, there is no report on a suitable internal standard compound for the determination of sterols. In this study, 19-hydroxycholesterol was proved to be a suitable internal standard compound for simultaneous and quantitative determination of several sterols in various analytical samples by capillary gas chromatography, including the quantitative determination of β-cholestanol in the human plasma. Moreover, the excellent condition of gas chromatographic analysis for quantitative determination of several sterols in various analytical samples was found

Altered Gamma-Band Activity in Recovered Depression

Background: The neurophysiological mechanisms of cognitive reactivity, the primary vulnerability factor of major depressive disorder (MDD) recurrence, remain unclear in individuals with recovered MDD (rMDD). Because gamma-band responses (GBRs) can be used to measure cognitive processing, they may also be useful for elucidating the mechanisms underlying cognitive reactivity. Identifying these mechanisms may permit the development of an index for predicting and preempting MDD recurrence. Here, to identify the neurophysiological mechanisms of cognitive reactivity, we examined the characteristics of the GBRs evoked/induced by emotional words in participants with and without rMDD after inducing a negative mood. Methods: Thirty-three healthy control participants and 18 participants with rMDD completed a lexical emotion identification task during electroencephalography along with assessments of cognitive reactivity after negative mood induction. Results: No between-group differences were identified for the task reaction times; however, the rMDD group had significantly higher cognitive reactivity scores than did the control group. Furthermore, the power of late GBRs to positive words was significantly greater in the rMDD group, with the greater power of late GBRs being related to higher cognitive reactivity. Limitations: Considering the population studied, our findings cannot be completely generalized to populations other than adolescents, people with rMDD, and those without a history of co-morbid disorders and early life stress. Conclusions: Our findings indicate that the dysfunction of neural circuits related to higher-order processes like memory and attention might underlie cognitive reactivity. Altered late GBRs to positive information may be persistent biomarkers of the depression recurrence risk

Increased amygdala reactivity following early life stress : a potential resilience enhancer role

Background: Amygdala hyper-reactivity is sometimes assumed to be a vulnerability factor that predates depression; however, in healthy people, who experience early life stress but do not become depressed, it may represent a resilience mechanism. We aimed to test these hypothesis examining whether increased amygdala activity in association with a history of early life stress (ELS) was negatively or positively associated with depressive symptoms and impact of negative life event stress in never-depressed adults. Methods: Twenty-four healthy participants completed an individually tailored negative mood induction task during functional magnetic resonance imaging (fMRI) assessment along with evaluation of ELS. Results: Mood change and amygdala reactivity were increased in never-depressed participants who reported ELS compared to participants who reported no ELS. Yet, increased amygdala reactivity lowered effects of ELS on depressive symptoms and negative life events stress. Amygdala reactivity also had positive functional connectivity with the bilateral DLPFC, motor cortex and striatum in people with ELS during sad memory recall. Conclusions: Increased amygdala activity in those with ELS was associated with decreased symptoms and increased neural features, consistent with emotion regulation, suggesting that preservation of robust amygdala reactions may reflect a stress buffering or resilience enhancing factor against depression and negative stressful events

DNA Methylation Profiles of the Brain-Derived Neurotrophic Factor (BDNF) Gene as a Potent Diagnostic Biomarker in Major Depression

Major depression, because of its recurring and life-threatening nature, is one of the top 10 diseases for global disease burden. Major depression is still diagnosed on the basis of clinical symptoms in patients. The search for specific biological markers is of great importance to advance the method of diagnosis for depression. We examined the methylation profile of 2 CpG islands (I and IV) at the promoters of the brain-derived neurotrophic factor (BDNF) gene, which is well known to be involved in the pathophysiology of depression. We analyzed genomic DNA from peripheral blood of 20 Japanese patients with major depression and 18 healthy controls to identify an appropriate epigenetic biomarker to aid in the establishment of an objective system for the diagnosis of depression. Methylation rates at each CpG unit was measured using a MassArray (R) system (SEQUENOM), and 2-dimensional hierarchical clustering analyses were undertaken to determine the validity of these methylation profiles as a diagnostic biomarker. Analyses of the dendrogram from methylation profiles of CpG I, but not IV, demonstrated that classification of healthy controls and patients at the first branch completely matched the clinical diagnosis. Despite the small number of subjects, our results indicate that classification based on the DNA methylation profiles of CpG I of the BDNF gene may be a valuable diagnostic biomarker for major depression

Anti-cancer activity of Chaga mushroom (Inonotus obliquus) against dog bladder cancer organoids

Despite its disadvantages, chemotherapy is still commonly used for the treatment of bladder cancer (BC). Developing natural supplements that can target cancer stem cells (CSCs) which cause drug resistance and distant metastasis is necessary. Chaga mushrooms are popular to have several health-promoting and anti-cancer potentials. Organoid culture can recapitulate tumor heterogeneity, epithelial environment, and genetic and molecular imprints of the original tissues. In the previous study, we generated dog bladder cancer organoids (DBCO) as a novel experimental model of muscle-invasive BCO. Therefore, the present study aimed to examine the anti-tumor potentials of Chaga mushroom extract (Chaga) against DBCO. Four strains of DBCO were used in the present study. Treatment with Chaga inhibited the cell viability of DBCO in a concentration-dependent way. Treatment of DBCO with Chaga has significantly arrested its cell cycle and induced apoptosis. Expression of bladder CSC markers, CD44, C-MYC, SOX2, and YAP1, declined in the Chaga-treated DBCO. Also, Chaga inhibited the phosphorylation of ERK in DBCO. Expression of downstream signals of ERK, C-MYC, and Cyclins (Cyclin-A2, Cyclin-D1, Cyclin-E1, and CDK4) was also inhibited by Chaga in DBCO. Interestingly, the combinational treatment of DBCO with Chaga and anti-cancer drugs, vinblastine, mitoxantrone, or carboplatin, showed a potentiating activity. In vivo, Chaga administration decreased tumor growth and weight of DBCO-derived xenograft in mice with the induction of necrotic lesions. In conclusion, Chaga diminished the cell viability of DBCO by inhibiting proliferation-related signals and stemness conditions as well as by arresting the cell cycle. Collectively, these data suggest the value of Chaga as a promising natural supplement that could potentiate the effect of adjuvant chemotherapy, lower its adverse effects, and thus, limit the recurrence and metastasis of BC