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    15 November 2018, Volume 13 Issue 11 Previous Issue    Next Issue
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    The unfolded protein response signaling and retinal Müller cell metabolism
    Kristen Kelly, Joshua J. Wang, Sarah X. Zhang
    2018, 13 (11):  1861-1870.  doi: 10.4103/1673-5374.239431
    Abstract ( 95 )   PDF (798KB) ( 190 )   Save

    The retina is one of the most energy demanding tissues in the body. Like most neurons in the central nervous system, retinal neurons consume high amounts of adenosine-5′-triphosphate (ATP) to generate visual signal and transmit the information to the brain. Disruptions in retinal metabolism can cause neuronal dysfunction and degeneration resulting in severe visual impairment and even blindness. The homeostasis of retinal metabolism is tightly controlled by multiple signaling pathways, such as the unfolded protein response (UPR), and the close interactions between retinal neurons and other retinal cell types including vascular cells and Müller glia. The UPR is a highly conserved adaptive cellular response and can be triggered by many physiological stressors and pathophysiological conditions. Activation of the UPR leads to changes in glycolytic rate, ATP production, de novo serine synthesis, and the hexosamine biosynthetic pathway, which are considered critical components of Müller glia metabolism and provide metabolic support to surrounding neurons. When these pathways are disrupted, neurodegeneration occurs rapidly. In this review, we summarize recent advance in studies of the UPR in Müller glia and highlight the potential role of the UPR in retinal degeneration through regulation of Müller glia metabolism.

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    Sequencing of high-efficacy disease-modifying therapies in multiple sclerosis: perspectives and approaches
    Francois Grand’Maison, Michael Yeung, Sarah A. Morrow, Liesly Lee, Francois Emond, Brian J. Ward, Pierre Laneuville, Robyn Schecter
    2018, 13 (11):  1871-1874.  doi: 10.4103/1673-5374.239432
    Abstract ( 89 )   PDF (414KB) ( 553 )   Save

    Multiple sclerosis (MS) is characterized by chronic inflammation in conjunction with neurodegeneration within the central nervous system. Most individuals with MS begin with a relapsing remitting course that later transitions to secondary progressive MS. Currently available disease-modifying therapies (DMTs) for relapsing MS have been demonstrated to reduce disease activity, however most patients require a change in therapy over the course of their disease. Treatment goals include the prevention of relapses and disability accumulation and to achieve this objective requires careful planning. Sequencing of DMTs for individual patients should be designed in such a way to maximize disease control and minimize risk based on the mechanism of action, pharmacokinetic and pharmacodynamic properties of each therapy. This includes the DMT patients are being switched from to those they are being switched to. The reversibility of immune system effects should be a key consideration for DMT sequence selection. This feature varies across DMTs and should factor more prominently in decision making as newer treatments become available for the prevention of disability accumulation in patients with progressive MS. In this short review, we discuss the landscape of existing therapies with an eye to the future when planning for optimal DMT sequencing. While no cure exists for MS, efforts are being directed toward research in neuroregeneration with the hope for positive outcomes.

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    Targeting prion-like protein spreading in neurodegenerative diseases
    Zhaohui Zhang, Shuke Nie, Liam Chen
    2018, 13 (11):  1875-1878.  doi: 10.4103/1673-5374.239433
    Abstract ( 109 )   PDF (562KB) ( 187 )   Save

    The infectious template-mediated protein conversion is a unique mechanism for the onset of rare and fatal neurodegenerative disorders known as transmissible spongiform encephalopathies, or prion diseases, which affect humans and other animal species. However, emerging studies are now demonstrating prion-like mechanisms of self-propagation of protein misfolding in a number of common, non-infectious neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. It has been proposed that distinct and unrelated proteins (beta-amyloid, tau, α-synuclein, TAR DNA-binding protein 43 and huntingtin, etc.) associated with common neurodegenerative disorders can seed conversion and spread via cell-to-cell transfer, sustaining the transmission of neurotoxic agents along a stereotypic route, sharing features at the heart of the intrinsic nature of prions. Here we review the most recent development on both the molecular mechanisms underlying the pathogenesis of prion-like neurodegenerative diseases as well as innovative methods and strategies for potential therapeutic applications.

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    Cadmium-induced neurotoxicity: still much ado
    Jacopo Junio Valerio Branca, Gabriele Morucci, Alessandra Pacini
    2018, 13 (11):  1879-1882.  doi: 10.4103/1673-5374.239434
    Abstract ( 164 )   PDF (385KB) ( 234 )   Save

    Cadmium (Cd) is a highly toxic heavy metal that accumulates in living system and as such is currently one of the most important occupational and environmental pollutants. Cd reaches into the environment by anthropogenic mobilization and it is absorbed from tobacco consumption or ingestion of contaminated substances. Its extremely long biological half-life (approximately 20–30 years in humans) and low rate of excretion from the body cause cadmium storage predominantly in soft tissues (primarily, liver and kidneys) with a diversity of toxic effects such as nephrotoxicity, hepatotoxicity, endocrine and reproductive toxicities. Moreover, a Cd-dependent neurotoxicity has been also related to neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases, amyotrophic lateral sclerosis, and multiple sclerosis. At the cellular level, Cd affects cell proliferation, differentiation, apoptosis and other cellular activities. Among all these mechanisms, the Cd-dependent interference in DNA repair mechanisms as well as the generation of reactive oxygen species, seem to be the most important causes of its cellular toxicity. Nevertheless, there is still much to find out about its mechanisms of action and ways to reduce health risks. This article gives a brief review of the relevant mechanisms that it would be worth investigating in order to deep inside cadmium toxicity.

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    Analysis of the trafficking system in blood-brain barrier models by high content screening microscopy
    Andrea E. Toth, Morten S. Nielsen
    2018, 13 (11):  1883-1884.  doi: 10.4103/1673-5374.239435
    Abstract ( 147 )   PDF (296KB) ( 193 )   Save

    The blood-brain barrier (BBB) and drug delivery: In our modern societies, the prevalence of nervous system disorders is increasing in relation to the aging population. To overcome this problem, several interesting pharmacons and biomolecules are introduced and tested each day. The biggest obstacle to delivering drugs into the brain parenchyma is the presence of the BBB.The BBB is a regulatory interface, which limits free transport of large and small molecules between the systemic circulation and the central nervous system. This regulation enables proper neuronal function and protection from outside toxic insults as well as maintenance of a stable ionic homeostasis. The morphological basis of the BBB is the monolayer of brain endothelial cells (BECs) in the cerebral microvessels. The adult human brain contains more than 600 km of capillaries, which differ fundamentally from other endothelial interfaces in the body. The tight inter-endothelial junctions connecting the cells reduce paracellular permeation of ions and other small hydrophilic solutes as well as larger molecules. Consequently, molecules have to enter the brain via transcellular transport mechanisms, but this access is also subjected to restrictive control. The metabolic and enzymatic barrier, formed by a unique expression pattern of enzymes and efflux pumps at the luminal membrane of BEC, limits BBB penetration of lipophilic drugs and other xenobiotics. Thus, the supply of essential nutrients to brain cells is tightly controlled via the vesicular-mediated transcellular transport mechanism. Transcytosis of larger molecules such as peptides and proteins are initially endocytosed by absorptive- and receptor-mediated mechanisms and then transcytosed via subcellular vesicles. This regulated vesicular transport is also known as absorptive- and receptor-mediated transcytosis. In addition to essential supplements, cell surface receptors are considered a potential gate for targeted delivery of large drugs to the brain. In the last decade, several publications have focused on the transferrin receptor as a target for bispecific antibodies and nanoparticles with pharmaceutical effect. Additionally, the cross-talk among endothelial cells and neighboring cells such as astroglia, pericytes, microglia, and neurons should be mentioned, which induce a unique barrier phenotype in BEC. This interaction is important for drug delivery, as it is known to affect expression of tight junction molecules, receptors, and transporters, as well as influence the subcellular vesicular system. In this paper, we introduce high content screening microscopy as an approach to analyze the subcellular vesicular structure and the trafficking system of the BBB in vitro. The method is particular useful to describe and compare differences between different culture set-ups.

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    Retinal remodeling following photoreceptor degeneration causes retinal ganglion cell death
    Diego García-Ayuso, Johnny Di Pierdomenico, MartaAgudo-Barriuso, Manuel Vidal-Sanz, María P. Villegas-Pérez
    2018, 13 (11):  1885-1886.  doi: 10.4103/1673-5374.239436
    Abstract ( 123 )   PDF (554KB) ( 169 )   Save

    The retina is the extension of the central nervous system that senses light. Cones and rods, situated in the outer retina, convert light into electrical signals that travel through intermediate neurons where these are further processed until they finally reach retinal ganglion cells (RGCs). The afferent neurons of the retina, the RGCs, send the visual information through their axons in the optic nerve to the retinorecipient nuclei in the brain, where is further analysed.

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    Potential therapeutic interventions based on the role of the endoplasmic reticulum stress response in progressive neurodegenerative diseases
    Basant K. Puri, Gerwyn Morris
    2018, 13 (11):  1887-1889.  doi: 10.4103/1673-5374.238614
    Abstract ( 123 )   PDF (151KB) ( 181 )   Save

    In 1945, Porter et al. published an electon microscopy study of cultured chick fibroblasts in which they observed: ‘a granular background and details of a darker lacelike reticulum which in places appears to be made up of chains of “vesicles”’ . This constituted the first published observation of the endoplasmic reticulum (ER) and, while it was not evident at that time, this cytoplasmic system of interconnecting membrane-lined channels, comprising vesicles, tubules and cisternae, has numerous important functions.

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    Tissue inhibitors of metalloproteases strike a nerve
    Veronica I. Shubayev, Alex Y. Strongin
    2018, 13 (11):  1890-1892.  doi: 10.4103/1673-5374.239437
    Abstract ( 121 )   PDF (404KB) ( 202 )   Save

    Signals of touch, pressure, pain, temperature, position, and vibration are transmitted from the peripheral nervous system (PNS) to the dorsal horn of the segmental spinal cord via pseudounipolar dorsal root ganglia (DRG) neurons. Sensory information gathering relies on functional integrity of DRG neurons and can be interrupted by PNS injury due to trauma, disease or exposure to drugs, toxins or viral pathogens. Despite the high regenerative capacity of DRG neurons, sensory recovery after PNS injury is often incomplete and severe neuropathic pain may last for years. Although numerous mechanisms of PNS injury have been established, neuropathic pain is refractory to therapy, contributing to the physical and emotional suffering of patients and the enormous economic burden to society.

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    Inhibition of neurite outgrowth using commercial myelin associated glycoprotein-Fc in neuro-2a cells
    Fu Liu, Mei-Ling Gao, Juan Bai, Ya-Fang Wang, Xia-Qing Li
    2018, 13 (11):  1893-1899.  doi: 10.4103/1673-5374.239438
    Abstract ( 143 )   PDF (1727KB) ( 159 )   Save

    Myelin-associated glycoprotein (MAG) inhibits the growth of neurites from nerve cells. Extraction and purification of MAG require complex operations; therefore, we attempted to determine whether commercially available MAG-Fc can replace endogenous MAG for research purposes. Immunofluorescence using specific antibodies against MAG, Nogo receptor (NgR) and paired immunoglobulin-like receptor B (PirB) was used to determine whether MAG-Fc can be endocytosed by neuro-2a cells. In addition, neurite outgrowth of neuro-2a cells treated with different doses of MAG-Fc was evaluated. Enzyme linked immunosorbent assays were used to measure RhoA activity. Western blot assays were conducted to assess Rho-associated protein kinase (ROCK) phosphorylation. Neuro-2a cells expressed NgR and PirB, and MAG-Fc could be endocytosed by binding to NgR and PirB. This activated intracellular signaling pathways to increase RhoA activity and ROCK phosphorylation, ultimately inhibiting neurite outgrowth. These findings not only verify that MAG-Fc can inhibit the growth of neural neurites by activating RhoA signaling pathways, similarly to endogenous MAG, but also clearly demonstrate that commercial MAG-Fc is suitable for experimental studies of neurite outgrowth.

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    Effect of acoustic stimuli in patients with disorders of consciousness: a quantitative electroencephalography study
    Min Wu, Wang-Xiao Bao, Jie Zhang, Yang-Fan Hu, Jian Gao, Ben-Yan Luo
    2018, 13 (11):  1900-1906.  doi: 10.4103/1673-5374.238622
    Abstract ( 176 )   PDF (925KB) ( 166 )   Save

    Auditory stimuli are proposed as beneficial neurorehabilitation methods in patients with disorders of consciousness. However, precise and accurate quantitative indices to estimate their potential effect remain scarce. Fourteen patients were recruited from the Neuro-Rehabilitation Unit of Hangzhou Hospital of Zhejiang Armed Police Corps of China. Altogether, there were seven cases of unresponsive wakefulness syndrome (five males and two females, aged 45.7 ± 16.8 years) and seven cases of minimally conscious state (six males and one female, aged 42.3 ± 20.8 years). Simultaneously, fourteen healthy controls (10 males and 4 females, aged 51.7 ± 9.7 years) also participated in this case-control experiment. Brain response to music, subjects’ own name, and noise was monitored by quantitative electroencephalography (QEEG) in the resting state and with acoustic stimulation. Predictive QEEG values in various brain regions were investigated. Our results show that cerebral activation was high in subjects stimulated by their own name, especially in the temporal lobe in patients with disorders of consciousness, and the frontal lobe in the control group. Further, during resting and stimulation, QEEG index (δ + θ/α + β ratio) negatively correlated with the Coma Recovery Scale-Revised score in traumatic disorders of consciousness patients. Hence, we speculate that a subject’s own name might be an effective awakening therapy for patients with disorders of consciousness. Moreover, QEEG index in specific stimulation states may be used as a prognostic indicator for disorders of consciousness patients (sensitivity, 75%; specificity, 50%). This clinical study has been registered at ClinicalTrials.gov (identifier: NCT03385291).

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    Symptom experience and symptom burden of patients following first-ever stroke within 1 year: a cross-sectional study
    Dan Shi, Zheng Li, Jian Yang, Bang-Zhong Liu, Hui Xia
    2018, 13 (11):  1907-1912.  doi: 10.4103/1673-5374.239440
    Abstract ( 157 )   PDF (245KB) ( 165 )   Save

    Symptoms that are multidimensional and concurrent should be assessed from different dimensions and managed together. Few studies have evaluated concurrent and multidimensional symptoms in patients with stroke. Most studies of stroke focused on dysfunctions and complications. We hypothesize that patients with stroke have a heavy symptom burden within 1 year. This study aimed to describe multidimensional and concurrent symptoms within 1 year after stroke. This study recruited 230 patients with stroke from the Rehabilitation Department of Xuhui District Center Hospital of Shanghai and the Shanghai Sunshine Rehabilitation Center in China from March to September 2017. The patients’ multidimensional symptom experience and symptom burden were analyzed using a self-made structured questionnaire and the influential factors for symptom burden were identified. The mean number of symptoms in patients with stroke was 11.7 ± 3.5. More than two thirds of the participants suffered from at least 10 co-occurring symptoms. Unilateral limb weakness had the highest prevalence and frequency. Participation restriction had the highest symptom dimensions of severity and distress. Lack of self-care ability (severity), memory deterioration (frequency), imbalance of body (distress), moodiness (distress), being unable to move limbs at will (distress), shoulder pain (distress), and slower response (frequency) were independent factors of the total symptom burden score. These findings can provide essential information for efficient symptom management of patients with stroke. This trial was registered with the ISRCTN registry (registration number: ISRCTN18421629).

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    Microbleeds in fronto-subcortical circuits are predictive of dementia conversion in patients with vascular cognitive impairment but no dementia
    Yang-Kun Chen, Wei-Min Xiao, Wei Li, Zhuo-Xin Ni, Yong-Lin Liu, Li Xu, Jian-Feng Qu, Chee H. Ng, Yu-Tao Xiang
    2018, 13 (11):  1913-1918.  doi: 10.4103/1673-5374.239441
    Abstract ( 154 )   PDF (541KB) ( 1092 )   Save

    Cerebral small vessel disease (CSVD) is a common etiology of vascular cognitive impairment with no dementia (V-CIND). Studies have revealed that cerebral microbleeds (CMBs), a feature of CSVD, contribute to cognitive impairment. However, the association between CMBs and dementia conversion in individuals with V-CIND is still unclear. Here, we analyzed the predictive role of CMBs in the conversion from V-CIND to dementia in CSVD patients. We recruited and prospectively assessed 85 patients with CSVD and V-CIND. V-CIND was evaluated using a series of comprehensive neuropsychological scales, including the Chinese version of the Montreal Cognitive Assessment and the Clinical Dementia Rating. MRI assessments were used to quantify lacunar infarcts, white matter hyperintensities, CMBs, and medial temporal lobe atrophy. Eighty-two of the 85 patients completed the assessment for dementia conversion at a 1-year follow-up assessment. Multivariate logistic regression analyses were conducted to examine independent clinical and MRI variables associated with dementia conversion. Twenty-four patients (29.3%) had converted to dementia at the 1-year follow-up, and these individuals had significantly more CMBs in the fronto-subcortical circuits. Multivariate logistic regression analyses revealed that the patients with CMBs in the fronto-subcortical circuits (odds ratio = 4.4; 95% confidence interval: 1.602–12.081, P = 0.004) and 5 or more CMBs overall (odds ratio = 17.6, 95% confidence interval: 3.23–95.84, P = 0.001) had a significantly increased risk of dementia at the 1-year follow-up. These findings indicate that CMBs in the fronto-subcortical circuits may be predictive of dementia conversion in CSVD patients with V-CIND, and thus extend the clinical significance of CMBs. This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800017077). Protocol version: 1.0.

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    LncRNA SNHG12 ameliorates brain microvascular endothelial cell injury by targeting miR-199a
    Fa-Qing Long, Qing-Jie Su, Jing-Xia Zhou, De-Sheng Wang, Peng-Xiang Li, Chao-Sheng Zeng, Yi Cai
    2018, 13 (11):  1919-1926.  doi: 10.4103/1673-5374.238717
    Abstract ( 146 )   PDF (2221KB) ( 152 )   Save

    Long non-coding RNAs regulate brain microvascular endothelial cell death, the inflammatory response and angiogenesis during and after ischemia/reperfusion and oxygen-glucose deprivation/reoxygenation (OGD/R) insults. The long non-coding RNA, SNHG12, is upregulated after ischemia/reperfusion and OGD/R in microvascular endothelial cells of the mouse brain. However, its role in ischemic stroke has not been studied. We hypothesized that SNHG12 positively regulates ischemic stroke, and therefore we investigated its mechanism of action. We established an OGD/R mouse cell model to mimic ischemic stroke by exposing brain microvascular endothelial cells to OGD for 0, 2, 4, 8, 16 or 24 hours and reoxygenation for 4 hours. Quantitative real-time polymerase chain reaction showed that SNHG12 levels in brain microvascular endothelial cells increased with respect to OGD exposure time. Brain microvascular endothelial cells were transfected with pcDNA-control, pcDNA-SNHG12, si-control, or si-SNHG12. After exposure to OGD for 16 hours, these cells were then analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, trypan blue exclusion, western blot, and capillary-like tube formation assays. Overexpression of SNHG12 inhibited brain microvascular endothelial cell death and the inflammatory response but promoted angiogenesis after OGD/R, while SNHG12 knockdown had the opposite effects. miR-199a was identified as a target of SNHG12, and SNHG12 overexpression reversed the effect of miR-199a on brain microvascular endothelial cell death, the inflammatory response, and angiogenesis. These findings suggest that SNHG12 suppresses endothelial cell injury induced by OGD/R by targeting miR-199a.

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    Molecular mechanism of panaxydol on promoting axonal growth in PC12 cells
    Wei-Peng Li, Ke Ma, Xiao-Yan Jiang, Rui Yang, Pei-Hua Lu, Bao-Ming Nie, Yang Lu
    2018, 13 (11):  1927-1936.  doi: 10.4103/1673-5374.239439
    Abstract ( 116 )   PDF (4952KB) ( 225 )   Save

    Nerve growth factor (NGF) promotes axonal growth in PC12 cells primarily by regulating the RTK-RAS-MEK-ERK pathway. Panaxydol, a polyacetylene isolated from Panax notoginseng, can mimic the effects of NGF. Panaxydol promotes neurite outgrowth in PC12 cells, but its molecular mechanism remains unclear. Indeed, although alkynol compounds such as panaxydol can increase intracellular cyclic adenosine 3′,5′-monophosphate (cAMP) levels and the ERK inhibitor U0126 inhibits alkynol-induced axonal growth, how pathways downstream of cAMP activate ERK have not been investigated. This study observed the molecular mechanism of panaxydol-, NGF- and forskolin-induced PC12 cell axon growth using specific signaling pathway inhibitors. The results demonstrated that although the RTK inhibitor SU5416 obviously inhibited the growth-promoting effect of NGF, it could not inhibit the promoting effect of panaxydol on axonal growth of PC12 cells. The adenylate cyclase inhibitor SQ22536 and cAMP-dependent protein kinase inhibitor RpcAMPS could suppress the promoting effect of forskolin and panaxydol on axonal growth. The ERK inhibitor U0126 inhibited axonal growth induced by all three factors. However, the PKA inhibitor H89 inhibited the promoting effect of forskolin on axonal growth but could not suppress the promoting effect of panaxydol. A western blot assay was used to determine the effects of stimulating factors and inhibitors on ERK phosphorylation levels. The results revealed that NGF activates the ERK pathway through tyrosine receptors to induce axonal growth of PC12 cells. In contrast, panaxydol and forskolin increased cellular cAMP levels and were inhibited by adenylyl cyclase inhibitors. The protein kinase A inhibitor H89 completely inhibited forskolin-induced axonal outgrowth and ERK phosphorylation, but could not inhibit panaxydol-induced axonal growth and ERK phosphorylation. These results indicated that panaxydol promoted axonal growth of PC12 cells through different pathways downstream of cAMP. Considering that exchange protein directly activated by cAMP 1 (Epac1) plays an important role in mediating cAMP signaling pathways, RNA interference experiments targeting the Epac1 gene were employed. The results verified that Epac1 could mediate the axonal growth signaling pathway induced by panaxydol. These findings suggest that compared with NGF and forskolin, panaxydol elicits axonal growth through the cAMP-Epac1-Rap1-MEK-ERK-CREB pathway, which is independent of PKA.

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    Translocator protein ligand, YL-IPA08, attenuates lipopolysaccharide-induced depression-like behavior by promoting neural regeneration
    Xiao-Ying Zhang, Li-Ming Zhang, Wei-Dong Mi, Yun-Feng Li
    2018, 13 (11):  1937-1944.  doi: 10.4103/1673-5374.239442
    Abstract ( 149 )   PDF (1071KB) ( 206 )   Save

    Translocator protein has received attention for its involvement in the pathogenesis of depression. This study assessed the effects of the new translocator protein ligand, YL-IPA08, on alleviating inflammation-induced depression-like behavior in mice and investigated its mechanism of action. Mice were intracerebroventricularly injected with 1, 10, 100 or 1000 ng lipopolysaccharide. The tail-suspension test and the forced swimming test confirmed that 100 ng lipopolysaccharide induced depression-like behavior. A mouse model was then established by intraventricular injection of 100 ng lipopolysaccharide. On days 16–24 after model establishment, mice were intragastrically administered 3 mg/kg YL-IPA08 daily. Immunohistochemistry was used to determine BrdU and NeuN expression in the hippocampus. YL-IPA08 effectively reversed the depression-like behavior of lipopolysaccharide-treated mice, restored body mass, increased the number of BrdU-positive cells, and the number and proportion of BrdU and NeuN double-positive cells. These findings indicate that YL-IPA08 can attenuate lipopolysaccharide-induced depression-like behavior in mice by promoting the formation of hippocampal neurons.

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    Glial fibrillary acidic protein levels are associated with global histone H4 acetylation after spinal cord injury in rats
    Mayara Ferraz de Menezes, Fabrício Nicola, Ivy Reichert Vital da Silva, Adriana Vizuete, Viviane Rostirola Elsner, Léder Leal Xavier, Carlos Alberto Saraiva Gonçalves, Carlos Alexandre Netto, Régis Gemerasca Mestriner
    2018, 13 (11):  1945-1952.  doi: 10.4103/1673-5374.239443
    Abstract ( 103 )   PDF (448KB) ( 197 )   Save

    Emerging evidence has suggested global histone H4 acetylation status plays an important role in neural plasticity. For instance, the imbalance of this epigenetic marker has been hypothesized as a key factor for the development and progression of several neurological diseases. Likewise, astrocytic reactivity - a wellknown process that markedly influences the tissue remodeling after a central nervous system injury - is crucial for tissue remodeling after spinal cord injury (SCI). However, the linkage between the above-mentioned mechanisms after SCI remains poorly understood. We sought to investigate the relation between both glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) (astrocytic reactivity classical markers) and global histone H4 acetylation levels. Sixty-one male Wistar rats (aged ~3 months) were divided into the following groups: sham; 6 hours post-SCI; 24 hours post-SCI; 48 hours post-SCI; 72 hours post-SCI; and 7 days post-SCI. The results suggested that GFAP, but not S100B was associated with global histone H4 acetylation levels. Moreover, global histone H4 acetylation levels exhibited a complex pattern after SCI, encompassing at least three clearly defined phases (first phase: no changes in the 6, 24 and 48 hours post-SCI groups; second phase: increased levels in the 72 hours post-SCI group; and a third phase: return to levels similar to control in the 7 days post-SCI group). Overall, these findings suggest global H4 acetylation levels exhibit distinct patterns of expression during the first week post-SCI, which may be associated with GFAP levels in the perilesional tissue. Current data encourage studies using H4 acetylation as a possible biomarker for tissue remodeling after spinal cord injury.

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    A rapid micro-magnetic resonance imaging scanning for three-dimensional reconstruction of peripheral nerve fascicles
    Zhi Yao1, 2, #, Li-Wei Yan, Tao Wang, Shuai Qiu, Tao Lin, Fu-Lin He, Ru-Heng Yuan, Xiao-Lin Liu, Jian Qi, Qing-Tang Zhu
    2018, 13 (11):  1953-1960.  doi: 10.4103/1673-5374.238718
    Abstract ( 138 )   PDF (1546KB) ( 263 )   Save

    The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging (Micro-MRI), an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by 1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions (Mannerist Solution/GD-DTPA contrast agent, distilled water) were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent (Mannerist Solution/GD-DTPA) and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.

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     Microencapsulated Schwann cell transplantation inhibits P2X3 receptor expression in dorsal root ganglia and neuropathic pain
    Ya-Ling Zhang, De-Jian Chen, Bao-Lin Yang, Tao-Tao Liu, Jia-Juan Li, Xiu-Qi Wang, Guo-Yong Xue, Zeng-Xu Liu
    2018, 13 (11):  1961-1967.  doi: 10.4103/1673-5374.238715
    Abstract ( 88 )   PDF (1035KB) ( 158 )   Save

    Schwann cell transplantation is a promising method to promote neural repair, and can be used for peripheral nerve protection and myelination. Microcapsule technology largely mitigates immune rejection of transplanted cells. We previously showed that microencapsulated olfactory ensheathing cells can reduce neuropathic pain and we hypothesized that microencapsulated Schwann cells can also inhibit neuropathic pain. Rat Schwann cells were cultured by subculture and then microencapsulated and were tested using a rat chronic constriction injury (CCI) neuropathic pain model. CCI rats were treated with Schwann cells or microencapsulated Schwann cells and were compared with sham and CCI groups. Mechanical withdrawal threshold and thermal withdrawal latency were assessed preoperatively and at 1, 3, 5, 7, 9, 11 and 14 days postoperatively. The expression of P2X3 receptors in L4–5 dorsal root ganglia of the different groups was detected by double-label immunofluorescence on day 14 after surgery. Compared with the chronic constriction injury group, mechanical withdrawal threshold and thermal withdrawal latency were higher, but the expression of P2X3 receptors was remarkably decreased in rats treated with Schwann cells and microencapsulated Schwann cells, especially in the rats transplanted with microencapsulated Schwann cells. The above data show that microencapsulated Schwann cell transplantation inhibits P2X3 receptor expression in L4–5 dorsal root ganglia and neuropathic pain.

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    Total brachial plexus injury: contralateral C7 root transfer to the lower trunk versus the median nerve
    Ye Jiang, Li Wang4, #, Jie Lao, Xin Zhao
    2018, 13 (11):  1968-1973.  doi: 10.4103/1673-5374.239444
    Abstract ( 88 )   PDF (566KB) ( 160 )   Save

    Contralateral C7 (cC7) root transfer to the healthy side is the main method for the treatment of brachial plexus root injury. A relatively new modification of this method involves cC7 root transfer to the lower trunk via the prespinal route. In the current study, we examined the effectiveness of this method using electrophysiological and histological analyses. To this end, we used a rat model of total brachial plexus injury, and cC7 root transfer was performed to either the lower trunk via the prespinal route or the median nerve via a subcutaneous tunnel to repair the injury. At 4, 8 and 12 weeks, the grasping test was used to measure the changes in grasp strength of the injured forepaw. Electrophysiological changes were examined in the flexor digitorum superficialis muscle. The change in the wet weight of the forearm flexor was also measured. Atrophy of the flexor digitorum superficialis muscle was assessed by hematoxylin-eosin staining. Toluidine blue staining was used to count the number of myelinated nerve fibers in the injured nerves. Compared with the traditional method, cC7 root transfer to the lower trunk via the prespinal route increased grasp strength of the injured forepaw, increased the compound muscle action potential maximum amplitude, shortened latency, substantially restored tetanic contraction of the forearm flexor muscles, increased the wet weight of the muscle, reduced atrophy of the flexor digitorum superficialis muscle, and increased the number of myelinated nerve fibers. These findings demonstrate that for finger flexion functional recovery in rats with total brachial plexus injury, transfer of the cC7 root to the lower trunk via the prespinal route is more effective than transfer to the median nerve via subcutaneous tunnel.

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    Hyperoside protects the blood-brain barrier from neurotoxicity of amyloid beta 1–42
    Chen-Yang Liu, Kuan Bai, Xiao-Hui Liu, Li-Mi Zhang, Gu-Ran Yu
    2018, 13 (11):  1974-1980.  doi: 10.4103/1673-5374.239445
    Abstract ( 157 )   PDF (1848KB) ( 189 )   Save

    Mounting evidence indicates that amyloid β protein (Aβ) exerts neurotoxicity by disrupting the blood-brain barrier (BBB) in Alzheimer’s disease. Hyperoside has neuroprotective effects both in vitro and in vivo against Aβ. Our previous study found that hyperoside suppressed Aβ1–42-induced leakage of the BBB, however, the mechanism remains unclear. In this study, bEnd.3 cells were pretreated with 50, 200, or 500 μM hyperoside for 2 hours, and then exposed to Aβ1–42 for 24 hours. Cell viability was determined using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay were used to analyze cell apoptosis. Western blot assay was carried out to analyze expression levels of Bax, Bcl-2, cytochrome c, caspase-3, caspse-8, caspase-9, caspase-12, occludin, claudin-5, zonula occludens-1, matrix metalloproteinase-2 (MMP-2), and MMP-9. Exposure to Aβ1–42 alone remarkably induced bEnd.3 cell apoptosis; increased ratios of cleaved caspase-9/caspase-9, Bax/Bcl-2, cleav ed caspase-8/caspase-8, and cleaved caspase-12/caspase-12; increased expression of cytochrome c and activity of caspase-3; diminished levels of zonula occludens-1, claudin-5, and occludin; and increased levels of MMP-2 and MMP-9. However, hyperoside pretreatment reversed these changes in a dose-dependent manner. Our findings confirm that hyperoside alleviates fibrillar Aβ1–42-induced BBB disruption, thus offering a feasible therapeutic application in Alzheimer’s disease.

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    Achyranthes bidentata polypeptide protects dopaminergic neurons from apoptosis induced by rotenone and 6-hydroxydopamine
    Su Peng, Li Xu, Jin-Yu Ma, Xiao-Song Gu, Cheng Sun
    2018, 13 (11):  1981-1987.  doi: 10.4103/1673-5374.239446
    Abstract ( 161 )   PDF (1591KB) ( 170 )   Save

    It has been well documented that Achyranthes bidentata polypeptides (ABPPs) are potent neuroprotective agents in several types of neurons. However, whether ABPPs protect dopaminergic neurons from apoptosis induced by neurotoxins is still unknown. This study was designed to observe the effect of ABPPk, a purified fraction of ABPPs, on apoptosis of dopaminergic neurons. SH-5YHY cells and primary dopaminergic neurons were pre-treated with ABPPk (25, 50, or 100 ng/mL) for 12 hours. Cells were then exposed to 6-hydroxydopamine (50 or 150 μM) or rotenone (50 or 200 μM) for 36 hours to induce cell apoptosis. Our results demonstrate that ABPPk markedly increased viability in SH-SY5Y cells and primary dopaminergic neurons, decreased lactate dehydrogenase activity and number of apoptotic dopaminergic neurons, elevated mitochondrial membrane potential, and increased Bcl-2/Bax ratio. These findings suggest that ABPPk protects dopaminergic neurons from apoptosis, and that ABPPk treatment might be an effective intervention for treating dopaminergic neuronal loss associated with disorders such as Parkinson’s disease.

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    Enriched environment elevates expression of growth associated protein-43 in the substantia nigra of SAMP8 mice
    Zhen-Yun Yuan, Jie Yang, Xiao-Wei Ma, Yan-Yong Wang, Ming-Wei Wang
    2018, 13 (11):  1988-1994.  doi: 10.4103/1673-5374.239447
    Abstract ( 112 )   PDF (695KB) ( 232 )   Save

    An enriched environment protects dopaminergic neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neuronal injury, but the underlying mechanism for this is not clear. Growth associated protein-43 (GAP-43) is closely associated with neurite outgrowth and axon regeneration during neural development. We speculate that an enriched environment can reduce damage to dopaminergic neurons by affecting the expression of GAP-43. This study is designed to test this hypothesis. Three-month-old female senescence-accelerated mouse prone 8 (SAMP8) mice were housed for 3 months in an enriched environment or a standard environment. These mice were then subcutaneously injected in the abdomen with 14 mg/kg MPTP four times at 2-hour intervals. Morris water maze testing demonstrated that learning and memory abilities were better in the enriched environment group than in the standard environment group. Reverse-transcription polymerase chain reaction, immunohistochemistry and western blot assays showed that mRNA and protein levels of GAP-43 in the substantia nigra were higher after MPTP application in the enriched environment group compared with the standard environment group. These findings indicate that an enriched environment can increase GAP-43 expression in SAMP8 mice. The upregulation of GAP-43 may be a mechanism by which an enriched environment protects against MPTP-induced neuronal damage.

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    Cognitive deficits and Alzheimer-like neuropathological impairments during adolescence in a rat model of type 2 diabetes mellitus
    Li Jin, Yi-Pei Li, Qiong Feng, Li Ren, Fang Wang, Guo-Jia Bo, Li Wang
    2018, 13 (11):  1995-2004.  doi: 10.4103/1673-5374.239448
    Abstract ( 144 )   PDF (1728KB) ( 245 )   Save

    Numerous studies have shown that many patients who suffer from type 2 diabetes mellitus exhibit cognitive dysfunction and neuronal synaptic impairments. Therefore, growing evidence suggests that type 2 diabetes mellitus has a close relationship with occurrence and progression of neurodegeneration and neural impairment in Alzheimer’s disease. However, the relationship between metabolic disorders caused by type 2 diabetes mellitus and neurodegeneration and neural impairments in Alzheimer’s disease is still not fully determined. Thus, in this study, we replicated a type 2 diabetic animal model by subcutaneous injection of newborn Sprague-Dawley rats with monosodium glutamate during the neonatal period. At 3 months old, the Barnes maze assay was performed to evaluate spatial memory function. Microelectrodes were used to measure electrophysiological function in the hippocampal CA1 region. Western blot assay was used to determine expression levels of glutamate ionotropic receptor NMDA type subunit 2A (GluN2A) and GluN2B in the hippocampus. Enzyme-linked immunosorbent assay was used to determine levels of interleukin-1β, tumor necrosis factor α, and interleukin-6 in the hippocampus and cerebral cortex, as well as hippocampal amyloid beta (Aβ)1–40 and Aβ1–42 levels. Our results showed that in the rat model of  type 2 diabetes mellitus caused by monosodium glutamate exposure during the neonatal period, latency was prolonged and the number of errors increased in the Barnes maze. Further, latency was increased and time in the escape platform quadrant shortened. Number of times crossing the platform was also reduced in the Morris water maze. After high frequency stimulation of the hippocampus, synaptic transmission was inhibited, expression of GluN2A and GluN2B were decreased in the hippocampus, expression of interleukin 1β, interleukin 6, and tumor necrosis factor α was increased in the hippocampus and cortex, and levels of Aβ1–40 and Aβ1–42 were increased in the hippocampus. These findings confirm that type 2 diabetes mellitus induced by neonatal monosodium glutamate exposure results in Alzheimer-like neuropathological changes and further causes cognitive deficits and neurodegeneration in young adulthood.

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    SIRT1 facilitates amyloid beta peptide degradation by upregulating lysosome number in primary astrocytes
    Min-Zhe Li, Liang-Jun Zheng, Jian Shen, Xin-Ya Li, Qi Zhang, Xue Bai, Qing-Song Wang, Jian-Guo Ji
    2018, 13 (11):  2005-2013.  doi: 10.4103/1673-5374.239449
    Abstract ( 169 )   PDF (1500KB) ( 201 )   Save

    Previous studies have shown that sirtuin 1 (SIRT1) reduces the production of neuronal amyloid beta (Aβ) and inhibits the inflammatory response of glial cells, thereby generating a neuroprotective effect against Aβ neurotoxicity in animal models of Alzheimer’s disease. However, the protective effect of SIRT1 on astrocytes is still under investigation. This study established a time point model for the clearance of Aβ in primary astrocytes. Results showed that 12 hours of culture was sufficient for endocytosis of oligomeric Aβ, and 36 hours sufficient for effective degradation. Immunofluorescence demonstrated that Aβ degradation in primary astrocytes relies on lysosome function. Enzymatic agonists or SIRT1 inhibitors were used to stimulate cells over a concentration gradient. Aβ was co-cultured for 36 hours in medium. Western blot assay results under different conditions revealed that SIRT1 relies on its deacetylase activity to promote intracellular Aβ degradation. The experiment further screened SIRT1 using quantitative proteomics to investigate downstream, differentially expressed proteins in the Aβ degradation pathway and selected the ones related to enzyme activity of SIRT1. Most of the differentially expressed proteins detected are close to the primary astrocyte lysosomal pathway. Immunofluorescence staining demonstrated that SIRT1 relies on its deacetylase activity to upregulate lysosome number in primary astrocytes. Taken together, these findings confirm that SIRT1 relies on its deacetylase activity to upregulate lysosome number, thereby facilitating oligomeric Aβ degradation in primary astrocytes.

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    Taurine protects against retinal and optic nerve damage induced by endothelin-1 in rats via antioxidant effects
    Natasha Najwa Nor Arfuzir, Renu Agarwal, Igor Iezhitsa, Puneet Agarwal, Sabrilhakim Sidek, Nafeeza Mohd Ismail
    2018, 13 (11):  2014-2021.  doi: 10.4103/1673-5374.239450
    Abstract ( 209 )   PDF (1137KB) ( 778 )   Save

    Endothelin-1 (ET-1), a potent vasoconstrictor, is involved in retinal vascular dysregulation and oxidative stress in glaucomatous eyes. Taurine (TAU), a naturally occurring free amino acid, is known for its neuroprotective and antioxidant properties. Hence, we evaluated its neuroprotective properties against ET-1 induced retinal and optic nerve damage. ET-1 was administered intravitreally to Sprague-Dawley rats and TAU was injected as pre-, co- or post-treatment. Animals were euthanized seven days post TAU injection. Retinae and optic nerve were examined for morphology, and were also processed for caspase-3 immunostaining. Retinal redox status was estimated by measuring retinal superoxide dismutase, catalase, glutathione, and malondialdehyde levels using enzyme-linked immuosorbent assay. Histopathological examination showed significantly improved retinal and optic nerve morphology in TAU-treated groups. Morphometric examination showed that TAU pre-treatment provided marked protection against ET-1 induced damage to retina and optic nerve. In accordance with the morphological observations, immunostaining for caspase showed a significantly lesser number of apoptotic retinal cells in the TAU pre-treatment group. The retinal oxidative stress was reduced in all TAU-treated groups, and particularly in the pre-treatment group. The findings suggest that treatment with TAU, particularly pre-treatment, prevents apoptosis of retinal cells induced by ET-1 and hence prevents the changes in the morphology of retina and optic nerve. The protective effect of TAU against ET-1 induced retinal and optic nerve damage is associated with reduced retinal oxidative stress.

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    Restoration of an injured lower dorsal ascending reticular activating system in a patient with intraventricular hemorrhage
    Sung Ho Jang, Sang Seok Yeo
    2018, 13 (11):  2022-2024.  doi: 10.4103/1673-5374.238719
    Abstract ( 212 )   PDF (2416KB) ( 165 )   Save

    The ascending reticular activating system (ARAS) plays a key role in the control of arousal and awareness for consciousness. It is well known that the ARAS originates from the reticular formation (RF) of the brainstem, and connects to the cerebral cortex via intralaminar nuclei (ILN) of thalamus, hypothalamus and direct pathways to the cerebral cortex. The hypothalamus is involved in the regulation of sleep and awareness which is associated with the main timekeeper of consciousness. By contrast, ILN is related to arousal of cortical and subcortical regions. Therefore, precise evaluation of each component of the ARAS is important for assessment and intervention of patients with impaired arousal or awareness. However, exact responsibility of each pathway of the ARAS in the regulation of consciousness remains a topic of interest and concern.

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