Metabotropic glutamate receptor 5 inhibits α-synuclein-induced microglia inflammation to protect from neurotoxicity in Parkinson's disease.

BACKGROUND: Microglia activation induced by α-synuclein (α-syn) is one of the most important factors in Parkinson's disease (PD) pathogenesis. However, the molecular mechanisms by which α-syn exerts neuroinflammation and neurotoxicity remain largely elusive. Targeting metabotropic glutamate receptor 5 (mGluR5) has been an attractive strategy to mediate microglia activation for neuroprotection, which might be an essential regulator to modulate α-syn-induced neuroinflammation for the treatment of PD. Here, we showed that mGluR5 inhibited α-syn-induced microglia inflammation to protect from neurotoxicity in vitro and in vivo. METHODS: Co-immunoprecipitation assays were utilized to detect the interaction between mGluR5 and α-syn in microglia. Griess, ELISA, real-time PCR, western blotting, and immunofluorescence assays were used to detect the regulation of α-syn-induced inflammatory signaling, cytokine secretion, and lysosome-dependent degradation. RESULTS: α-syn selectively interacted with mGluR5 but not mGluR3, and α-syn N terminal deletion region was essential for binding to mGluR5 in co-transfected HEK293T cells. The interaction between these two proteins was further detected in BV2 microglia, which was inhibited by the mGluR5 specific agonist CHPG without effect by its selective antagonist MTEP. Moreover, in both BV2 cells and primary microglia, activation of mGluR5 by CHPG partially inhibited α-syn-induced inflammatory signaling and cytokine secretion and also inhibited the microglia activation to protect from neurotoxicity. We further found that α-syn overexpression decreased mGluR5 expression via a lysosomal pathway, as evidenced by the lysosomal inhibitor, NH4Cl, by blocking mGluR5 degradation, which was not evident with the proteasome inhibitor, MG132. Additionally, co-localization of mGluR5 with α-syn was detected in lysosomes as merging with its marker, LAMP-1. Consistently, in vivo experiments with LPS- or AAV-α-syn-induced rat PD model also confirmed that α-syn accelerated lysosome-dependent degradation of mGluR5 involving a complex, to regulate neuroinflammation. Importantly, the binding is strengthened with LPS or α-syn overexpression but alleviated by urate, a potential clinical biomarker for PD. CONCLUSIONS: These findings provided evidence for a novel mechanism by which the association of α-syn with mGluR5 was attributed to α-syn-induced microglia activation via modulation of mGluR5 degradation and its intracellular signaling. This may be a new molecular target for an effective therapeutic strategy for PD pathology.

Effect of Transcranial Alternating Current Stimulation for the Treatment of Chronic Insomnia: A Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Clinical Trial.

BACKGROUND: Not all adults with chronic insomnia respond to the recommended therapeutic options of cognitive behavioral therapy and approved hypnotic drugs. Transcranial alternating current stimulation (tACS) may offer a novel potential treatment modality for insomnia. OBJECTIVES: This study aimed to examine the efficacy and safety of tACS for treating adult patients with chronic insomnia. METHODS: Sixty-two participants with chronic primary insomnia received 20 daily 40-min, 77.5-Hz, 15-mA sessions of active or sham tACS targeting the forehead and both mastoid areas in the laboratory on weekdays for 4 consecutive weeks, followed by a 4-week follow-up period. The primary outcome was response rate measured by the Pittsburgh Sleep Quality Index (PSQI) at week 8. Secondary outcomes were remission rate, insomnia severity, sleep onset latency (SOL), total sleep time (TST), sleep efficiency, sleep quality, daily disturbances, and adverse events at the end of the 4-week intervention and at the 4-week follow-up. RESULTS: Of 62 randomized patients, 60 completed the trial. During the 4-week intervention, 1 subject per group withdrew due to loss of interest and time restriction, respectively. Based on PSQI, at 4-week follow-up, the active group had a higher response rate compared to the sham group (53.4% [16/30] vs. 16.7% [5/30], p = 0.009), but remission rates were not different between groups. At the end of the 4-week intervention, the active group had higher response and remission rates than the sham group (p < 0.001 and p = 0.026, respectively). During the trial, compared with the sham group, the active group showed a statistically significant decrease in PSQI total score, a shortened SOL, an increased TST, improved sleep efficiency, and improved sleep quality (p < 0.05 or p < 0.001). Post hoc analysis revealed that, in comparison with the sham group, the active group had improved symptoms, except for daily disturbances, at the end of the 4-week intervention, and significant improvements in all symptoms at the 4-week follow-up. No adverse events or serious adverse responses occurred during the study. CONCLUSION: The findings show that the tACS applied in the present study has potential as an effective and safe intervention for chronic insomnia within 8 weeks.

Inhibition of SNK-SPAR signaling pathway promotes the restoration of motor function in a rat model of ischemic stroke.

This study aimed to investigate the effects of SPAR signaling pathway on the restoration of motor function in ischemic stroke (IS). Sprague-Dawley male rats were separated into the control and sham groups, as well as the group for middle cerebral artery occlusion (MCAO) model establishment. Successfully established rat ischemic models were randomly divided into model, SNKMCAO-del and pcDNA3.1-SNK groups. The evaluation of motor function among the rats in each group was assessed using a balance beam, a screen test and the Garcia scoring method. CatWalk gait analysis was employed to evaluate the effect of the SNK signaling pathway on rat motor function. Triphenyltetrazolium chloride (TTC) and TUNEL staining were techniques were utilized for cerebral infarction (CI) area as well for hippocampal neuron apoptosis. The quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting methods were performed to detect mRNA and protein expressions of SNK and SPAR. When compared with the model group, the SNKMCAO-del group displayed decreased motor function score and CI area, while contrasting results were observed in the pcDNA3.1-SNK group. According to the results obtained from the CatWalk gait analysis, the SNKMCAO-del group showed a clear improvement compared to the model group whereas the pcDNA3.1-SNK group exhibited poorer results than the model group in the objective parameters of the study, such as movement, speed, running duration, print area, maximal contact area, maximal, mean intensity, and stride length. These findings suggested that SNK gene silencing promotes motor function by inhibiting the SNK-SPAR signaling pathway in rats with ischemic stroke.

Pontine control of rapid eye movement sleep and fear memory.

AIMS: We often experience dreams of strong irrational and negative emotional contents with postural muscle paralysis during rapid eye movement (REM) sleep, but how REM sleep is generated and its function remain unclear. In this study, we investigate whether the dorsal pontine sub-laterodorsal tegmental nucleus (SLD) is necessary and sufficient for REM sleep and whether REM sleep elimination alters fear memory. METHODS: To investigate whether activation of SLD neurons is sufficient for REM sleep induction, we expressed channelrhodopsin-2 (ChR2) in SLD neurons by bilaterally injecting AAV1-hSyn-ChR2-YFP in rats. We next selectively ablated either glutamatergic or GABAergic neurons from the SLD in mice in order to identify the neuronal subset crucial for REM sleep. We finally  investigated the role of REM sleep in consolidation of fear memory using rat model with complete SLD lesions. RESULTS: We demonstrate the sufficiency of the SLD for REM sleep by showing that photo-activation of ChR2 transfected SLD neurons selectively promotes transitions from non-REM (NREM) sleep to REM sleep in rats. Diphtheria toxin-A (DTA) induced lesions of the SLD in rats or specific deletion of SLD glutamatergic neurons but not GABAergic neurons in mice completely abolish REM sleep, demonstrating the necessity of SLD glutamatergic neurons for REM sleep. We then show that REM sleep elimination by SLD lesions in rats significantly enhances contextual and cued fear memory consolidation by 2.5 and 1.0 folds, respectively, for at least 9 months. Conversely, fear conditioning and fear memory trigger doubled amounts of REM sleep in the following night, and chemo-activation of SLD neurons projecting to the medial septum (MS) selectively enhances hippocampal theta activity in REM sleep; this stimulation immediately after fear acquisition reduces contextual and cued fear memory consolidation by 60% and 30%, respectively. CONCLUSION: SLD glutamatergic neurons generate REM sleep and REM sleep and SLD via the hippocampus particularly down-regulate contextual fear memory.

[Characteristic of microglial activation of hippocampus in experimental epileptic rats].

OBJECTIVE: To investigate the characteristics of microglial activation of hippocampus in experimental epileptic rats. METHODS: Morphological changes and proliferation of OX-42 positive cells were compared at different time points after status of epilepticus (SE) in lithium-pilocarpine induced epileptic rats. RESULTS: OX-42 positive cells were activated after SE, which increased to a peak at 3-7 d and in a relatively stable state at 7-14 d; then gradually decreased after 14d and returned to slightly higher level than previously at 21 d. CONCLUSION: Inflammatory injury, microglial activation and cell proliferation are closely related after seizures, microglial activation may be an important mechanism in the inflammatory injury of epilepsy.

Protocol on transcranial alternating current stimulation for the treatment of major depressive disorder: a randomized controlled trial.

BACKGROUND: Transcranial alternating current stimulation (tACS) offers a new approach for adult patients with major depressive disorder (MDD). The study is to evaluate the efficacy and safety of tACS treating MDD. METHODS: This is an 8-week, double-blind, randomized, placebo-controlled study. Ninety-two drug-naive patients with MDD aged 18 to 65 years will receive 20 daily 40-min, 77.5-Hz, 15-mA sessions of active or sham tACS targeting the forehead and both mastoid areas on weekdays for 4 consecutive weeks (week 4), following a 4-week observation period (week 8). The primary outcome is the remission rate defined as the 17-item Hamilton depression rating scale (HDRS-17) score ≤7 at week 8. Secondary outcomes are the rates of response at weeks 4 and 8 and rate of remission at week 4 based on HDRS-17, the proportion of participants having improvement in the clinical global impression-improvement, the change in HDRS-17 score (range, 0-52, with higher scores indicating more depression) over the study, and variations of brain imaging and neurocognition from baseline to week 4. Safety will be assessed by vital signs at weeks 4 and 8, and adverse events will be collected during the entire study. DISCUSSION: The tACS applied in this trial may have treatment effects on MDD with minimal side effects. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800016479; http://www.chictr.org.cn/showproj.aspx?proj=22048.

Relationships between Rapid Eye Movement Sleep Behavior Disorder and Neurodegenerative Diseases: Clinical Assessments, Biomarkers, and Treatment.

OBJECTIVE: Rapid eye movement sleep behavior disorder (RBD) is characterized by dream enactment and loss of muscle atonia during rapid eye movement sleep. RBD is closely related to α-synucleinopathies including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Many studies have investigated the markers of imaging and neurophysiological, genetic, cognitive, autonomic function of RBD and their predictive value for neurodegenerative diseases. This report reviewed the progress of these studies and discussed their limitations and future research directions. DATA SOURCES: Using the combined keywords: "RBD", "neurodegenerative disease", "Parkinson disease", and "magnetic resonance imaging", the PubMed/MEDLINE literature search was conducted up to January 1, 2018. STUDY SELECTION: A total of 150 published articles were initially identified citations. Of the 150 articles, 92 articles were selected after further detailed review. This study referred to all the important English literature in full. RESULTS: Single-nucleotide polymorphisms in SCARB2 (rs6812193) and MAPT (rs12185268) were significantly associated with RBD. The olfactory loss, autonomic dysfunction, marked electroencephalogram slowing during both wakefulness and rapid eye movement sleep, and cognitive impairments were potential predictive markers for RBD conversion to neurodegenerative diseases. Traditional structural imaging studies reported relatively inconsistent results, whereas reduced functional connectivity between the left putamen and substantia nigra and dopamine transporter uptake demonstrated by functional imaging techniques were relatively consistent findings. CONCLUSIONS: More longitudinal studies should be conducted to evaluate the predictive value of biomarkers of RBD. Moreover, because the glucose and dopamine metabolisms are not specific for assessing cognitive cognition, the molecular metabolism directly related to cognition should be investigated. There is a need for more treatment trials to determine the effectiveness of interventions of RBD on preventing the conversion to neurodegenerative diseases.

[A study on expression of HIF-1alpha and EPO in the hippocampus of rats with vascular dementia].

OBJECTIVE: To observe the expression rule of hypoxia inducible factor-1 (HIF-1alpha) and erythropoietion (EPO) in the formation of vascular dementia (VD) and investigate the possible pathogenesis of VD. METHODS: Rats of experimental group were treated with a permanent bilateral common carotid arteries (CCA) occlusion (2-VO) for establishing vascular dementia model. Rats were evaluated on learning-memory ability by Y-type water maze test. The dynamic expression of HIF-1alpha and EPO in hippocampal CA1 region were measured by immunohistochemical assay method. RESULTS: (1) The learning-memory ability of rats in VD groups was progressively decreased as the ischemic duration prolonged (P < 0.05); (2) In VD group, the expression of HIF-1alpha and EPO in hippocampal CA1 region were most obvious at 1 w, and then declined progressively but still above the normal level (P < 0.01); (3) In VD group, the expression of HIF-1alpha and EPO at each ischemic point and their corresponding learning-memory ability were in significant correlation at the 0.01 level. CONCLUSION: Both HIF-1alpha and EPO contribute to the formation of VD, and HIF-1/EPO anoxic signal transduction may play a protecting role in this process.

Comparison Study of Polysomnographic Features in Multiple System Atrophy-cerebellar Types Combined with and without Rapid Eye Movement Sleep Behavior Disorder.

BACKGROUND: The brain stem is found to be impaired in multiple system atrophy-cerebellar types (MSA-C). Rapid eye movement (REM) sleep behavior disorder (RBD) is reported as a marker of progressive brain stem dysfunction. Few systematic studies about the sleep disturbances in MSA-C patients combined with or without RBD were reported. This study aimed to explore the polysomnographic (PSG) features of sleep disturbances between MSA-C patients with and without RBD. METHODS: Totally, 46 MSA-C patients (23 with RBD, and 23 without RBD) were enrolled in this study. All patients underwent a structured interview for their demographic data, history of sleep pattern, and movement disorders; and then, overnight video-PSG was performed in each patient. All the records were evaluated by specialists at the Sleep Medicine Clinic for RBD and the Movement Disorder Clinic for MSA-C. The Student's t-test, Mann-Whitney U-test for continuous variables, and the Chi-square test for categorical variables were used in this study. RESULTS: MSA-C patients with RBD had younger visiting age (52.6 ± 7.4 vs. 56.7 ± 6.0 years, P = 0.046) and shorter duration of the disease (12.0 [12.0, 24.0] vs. 24.0 [14.0, 36.0] months, P = 0.009) than MSA-C patients without RBD. MSA-C with RBD had shorter REM sleep latency (111.7 ± 48.2 vs. 157.0 ± 68.8 min, P = 0.042), higher percentage of REM sleep (14.9% ±4.0% vs. 10.0% ± 3.2%, P = 0.019), and lower Stage I (9.5% ±7.2% vs. 15.9% ±8.0%, P = 0.027) than MSA-C without RBD. Moreover, MSA-C patients with RBD had more decreased sleep efficiency (52.4% ±12.6% vs. 65.8% ±15.9%, P = 0.029) than that without RBD. CONCLUSIONS: In addition to the RBD, MSA-C patients with RBD had other more severe sleep disturbances than those without RBD. The sleep disorders of MSA patients might be associated with the progress of the disease.

[Effects of recombinant human erythropoietin on brain-derived neurotrophic factor expression in different brain regions of aging rats].

OBJECTIVE: To explore the effect of recombinant human erythropoietin (rhEPO) on expression of brain-derived neurotrophic factor (BDNF) in different brain regions of aging rats. METHODS: Forty male SD rats were randomized equally into negative control group, D-galactose group, EPO treatment group, and positive control group. Rat models of subacute aging were established by continuous subcutaneous injection of 5% D-galactose. Immunohistochemical staining was used to analyze the variation of BDNF expressions in different brain regions of the aging rats with different treatments. RESULTS: Significant brain region-specific differences in BDNF expression were found among the rats in different groups. Compared with those in the negative control group, the numbers of BDNF-positive cells in the hippocampal CA1 region, CA3 region, dentate gyrus (DG) and frontal cortex were all decreased obviously in D-galactose group (P<0.05) but increased in both EPO group and the positive control group (P<0.05) without significant differences between the latter two groups. In the rats in the same group, the number of BDNF-positive cells varied markedly in different brain regions (P<0.05), and the expression level of BDNF was the highest in the frontal cortex followed by the hippocampal CA3 region and the dentate gyrus, and was the lowest in the hippocampal CA1 region. CONCLUSION: Treatment with rhEPO enhances the expression of BDNF in rat neural cells, suggesting that rhEPO may protect the nervous system from aging by regulating the BDNF pathway.

Immature dendritic cell exosomes suppress experimental autoimmune myasthenia gravis.

Immature dendritic cell-derived exosomes (iMDEX) display a certain degree of immunosuppressive activity in autoimmune diseases. However, the role of iMDEX in experimental autoimmune myasthenia gravis (EAMG) is still unclear. Therefore, we tested the effects of mouse bone marrow (BM)-derived iMDEX on tolerance induction in a mouse model of EAMG. In this study, we found that the CELLine culture system produced more exosomes, the morphology and phenotype of these exosomes were found to be identical when compared with traditional cell culture. And, iMDEX(1000) ameliorated the progression of EAMG by reducing AChR-reactive lymphocyte proliferation, AChR antibody levels and pro-inflammatory cytokine levels.

Repetitive Transcranial Magnetic Stimulation for the Treatment of Restless Legs Syndrome.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique used to alter cortex excitability that has been proposed as an efficient method for treating brain hyperexcitability or hypoexcitability disorders. The aim of this study was to investigate whether high-frequency rTMS could have any beneficial effects in restless legs syndrome (RLS). METHODS: Fourteen patients with RLS were given high-frequency rTMS (15 Hz, 100% motor threshold) to the leg representation motor cortex area of the frontal lobe for 14 sessions over 18 days. Patients were diagnosed according to the international criteria proposed by the International Restless Legs Syndrome Study Group in 2003. The International RLS Rating Scale (IRLS-RS), Pittsburgh Sleep Quality Index (PSQI), Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale were used to evaluate the severity of RLS, sleep quality, anxiety and depression, respectively. The scale scores were evaluated at four-time points (baseline, end of the 14 th session, and at 1- and 2-month posttreatment). One-way analysis of variance was used to compare scale scores at different time points. RESULTS: There was significant improvement in the IRLS-RS (from 23.86 ± 5.88 to 11.21 ± 7.23, P < 0.05), PSQI (from 15.00 ± 4.88 to 9.29 ± 3.91, P < 0.05), and HAMA (from 17.93 ± 7.11 to 10.36 ± 7.13, P < 0.05) scale scores at the end of 14 th session, with ongoing effects lasting for at least 2 months. CONCLUSIONS: High-frequency rTMS can markedly alleviate the motor system symptoms, sleep disturbances, and anxiety in RLS patients. These results suggest that rTMS might be an option for treating RLS.

[Expression of hypoxia inducible factor-1alpha in different brain regions in aged rats].

OBJECTIVE: To observe the distribution of hypoxia inducible factor-1alpha (HIF-1alpha) in different brain regions in aged rats and investigate the role of HIF-1alpha in the aging process of the nervous system. METHODS: The Nissl bodies and HIF-1alpha expression in different brain regions were observed in rats aged 3 and 30 months using Nissl staining and immunohistochemical method, respectively. RESULTS: In the 30-month-old rats, the neural cells in 4 different brain regions presented with large cell body and loose alignment, containing reduced Nissl bodies in the cytoplasm. Compared with the 3-month-old rats, the aged rats showed greater number of HIF-1alpha-positive cells in the brain (P < 0.01), and the number varied significantly between the different brain regions (P < 0.01). The CA3 region contained the greatest number of positive cells, which were fewer in the motor cortex and cerebellum. CONCLUSION: The capacity for protein synthesis in the neural cells is weakened but the expression of HIF-1alpha increased in aged rats, suggesting the important role that HIF-1alpha may play in the aging process of the nervous system, especially in hypomnesis.