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    15 February 2016, Volume 11 Issue 2 Previous Issue    Next Issue
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    Cardiovascular dysfunction following spinal cord injury
    Elizabeth Partida, Eugene Mironets, Shaoping Hou, Veronica J. Tom
    2016, 11 (2):  189-194.  doi: 10.4103/1673-5374.177707
    Abstract ( 362 )   PDF (419KB) ( 460 )   Save

    Both sensorimotor and autonomic dysfunctions often occur after spinal cord injury (SCI). Particularly, a high thoracic or cervical SCI interrupts supraspinal vasomotor pathways and results in disordered hemodynamics
    due to deregulated sympathetic outflow. As a result of the reduced sympathetic activity, patients with SCI may experience hypotension, cardiac dysrhythmias, and hypothermia post-injury. In the chronic phase, changes within the CNS and blood vessels lead to orthostatic hypotension and life-threatening autonomic
    dysreflexia (AD). AD is characterized by an episodic, massive sympathetic discharge that causes severe hypertension associated with bradycardia. The syndrome is often triggered by unpleasant visceral or sensory stimuli below the injury level. Currently the only treatments are palliative – once a stimulus elicits
    AD, pharmacological vasodilators are administered to help reduce the spike in arterial blood pressure. However, a more effective means would be to mitigate AD development by attenuating contributing mechanisms,
    such as the reorganization of intraspinal circuits below the level of injury. A better understanding of the neuropathophysiology underlying cardiovascular dysfunction after SCI is essential to better develop novel therapeutic approaches to restore hemodynamic performance.

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    Practical application of the neuroregenerative properties of ketamine: real world treatment experience
    Theodore A. Henderson
    2016, 11 (2):  195-200.  doi: 10.4103/1673-5374.177708
    Abstract ( 193 )   PDF (353KB) ( 411 )   Save

    While controversial, ketamine has emerged as an effective treatment for refractory depression. Serial infusions have been performed 3 times per week, but our practical experience has challenged this precept concerning infusion frequency. Depression is associated with neuron loss, reduced synapse numbers, and dearborization of dendrites. Ketamine appears to potently induce mechanisms which reverse these neurodegenerative processes. Ketamine not only blocks the glutamate receptor, it activates eukaroyotic elongation factor 2 (eEF2). This, in turn, activates brain-derived neurotrophic factor (BDNF) protein synthesis. This is thought to underlie ketamine’s enduring benefits. In addition, ketamine alters glycogen synthase kinase-3 (GSK-3) phosphorylation, probably responsible for its rapid antidepressant effect. Notably, inhibition of the BDNF receptor does not block the immediate benefits of ketamine, but does prevent the enduring effects. Neuro-Luminance Ketamine Infusion Centers have been treating patients with serial ketamine infusions for over three years. Our methods differ from what is often reported, as we perform infusions only once per week and generally do not perform more than five infusions. Data from 100 patients showed that 80% of the patients responded. The baseline Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR) score was 17.8 ± 2.8. Responders to ketamine showed a drop in QIDS-SR score of 10.8 ± 3.5, while non-responders showed a 0.8 ± 1.8 change. Moreover, they often had persistent benefits over several months. Recently, it was proposed that psychotomimetic effects are necessary during a ketamine infusion to yield effective antidepressant benefits. Yet, only one patient in our clinic has experienced hallucinations in three years. Nevertheless, 80% of our patients show clinical improvement. Further studies of clinical methods for ketamine infusion therapy are encouraged.

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    Exergames: neuroplastic hypothesis about cognitive improvement and biological effects on physical function of institutionalized older persons
    Renato Sobral Monteiro-Junior, César Augusto Otero Vaghetti, Osvaldo José M. Nascimento, Jerson Laks, Andrea Camaz Deslandes
    2016, 11 (2):  201-204.  doi: 10.4103/1673-5374.177709
    Abstract ( 159 )   PDF (382KB) ( 428 )   Save

    Exergames can be considered a dual task because the games are performed by a man-videogame interface, requiring cognitive and motor functions simultaneously. Although the literature has shown improvements of cognitive and physical functions due to exergames, the intrinsic mechanisms involved in these functional changes have still not been elucidated. The aims of the present study were (1) to demonstrate the known biological mechanisms of physical exercise regarding muscle adaptation and establish a relationship with exergames; and (2) to present a neurobiological hypothesis about the neuroplastic effects of exergames on the cognitive function of institutionalized older persons. These hypotheses are discussed.

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    Neurotrophic factor therapy for Parkinson’s disease: past, present and future
    Aideen M. Sullivan, Gerard W. O’Keeffe
    2016, 11 (2):  205-207.  doi: 10.4103/1673-5374.177710
    Abstract ( 248 )   PDF (301KB) ( 434 )   Save
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    Considering calcium-binding proteins in invertebrates: multi-functional proteins that shape neuronal growth
    Charles R. Tessier
    2016, 11 (2):  208-209.  doi: 10.4103/1673-5374.177711
    Abstract ( 447 )   PDF (422KB) ( 387 )   Save

    Calcium is a critical second messenger molecule in all cells and is vital in neurons for synaptic transmission. Given this incredible importance, calcium ions are tightly controlled by a host of molecular players including ion channels, sensors and buffering proteins. Calcium can act directly by binding to signaling molecules or calcium’s effects can be indirect, for example by altering nuclear histones which can lead to changes in gene transcription. All of these mechanisms come into play in developing axons as calcium is required for both axon pathfinding and branching. Furthermore, after neuronal injury, waves of calcium originating at the site of axon segmentation and propagating to the nucleus have long been known to be required for regeneration. These changes in intracellular calcium concentrations [Ca2+]i must be properly controlled or else new growth cones may fail to form and degeneration of the neuron may occur. While many of the molecular players involved in these calcium-dependent processes have been identified, calcium buffering proteins have often been undervalued for their role in regulating axon growth either during normal development or in the event of injury.

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    Casein kinase signaling in axon regeneration
    Nagi G. Ayad, Jae K. Lee, Vance P. Lemmon
    2016, 11 (2):  210-211.  doi: 10.4103/1673-5374.177713
    Abstract ( 308 )   PDF (169KB) ( 383 )   Save

    Recent studies suggest that cell cycle pathways may contain therapeutic targets important for neurotrauma. An example of this is the finding that the vertebrate cell cycle exploits proteolysis pathways yet these activities persist in fully differentiated cells that have exited the cell cycle such as neurons. We have known for some time that a ubiquitin ligase, the Anaphase-Promoting Complex (APC/C) required for progression through the M and G1 phases of the cell cycle, is also active in fully differentiated neurons that are no longer dividing. Several studies demonstrated roles for APC/C in restraining neurite outgrowth in fully differentiated neurons. Depleting the APC/C activator Cdh1 increased neurite outgrowth in cerebellar granule cells. Similarly, overexpression of nondegradable APC/C substrates such as SnoN and Id2 promoted neurite outgrowth in cerebellar granule cells. Interestingly, nondegradable Id2 overexpression increased neurite outgrowth in a regeneration model, suggesting that modulating protein levels by affecting their degradation rates may be therapeutically attractive in preclinical models of neurotrauma. In addition to in vitro studies with CK1δ it will be important to determine whether CK1δ inhibition reduces neurite outgrowth in vivo in naïve animals but also in models of spinal cord injury. Given the reported role for CK1δ in neurite outgrowth in vitro the prediction is that CK1δ inhibition should reduce neurite outgrowth. However, after spinal cord injury neurite outgrowth is also affected by inflammation. Studies have shown that inhibition of inflammation in astrocytes reduces inflammation and increases neurite outgrowth after SCI. Thus, a possible role for CK1δ in promoting inflammation after SCI may suggest that CK1δ inhibition may be therapeutically attractive. Consistent with this notion is the finding that CK1δ inhibition reduces neuropathic pain after SCI, possibly via reducing inflammation. Future studies will delineate the role of CK1δ in promoting inflammation and neurite outgrowth after SCI. Furthermore, the contribution of APC/C dependent degradation should be analyzed to determine whether it is feasible to simultaneously stimulate APC/C-dependent degradation of CK1δ in inflammatory cells while inhibiting the APC/C-CK1δ interaction in neurons.

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    Tissue-type plasminogen activator is a modulator of the synaptic vesicle cycle
    Manuel Yepes
    2016, 11 (2):  212-213.  doi: 10.4103/1673-5374.177712
    Abstract ( 255 )   PDF (301KB) ( 416 )   Save

    Tissue-type plasminogen activator (tPA) is a serine proteinase that catalyzes the conversion of plasminogen (PLG) into plasmin (Pl). For a long time after its discovery it was thought that tPA's main source was the endothelial cell and that therefore its chief role was to generate plasmin in the vascular system. However, this concept was challenged four decades later when a group of investigators identified tPA-catalyzed proteolysis in well-defined areas of the brain, namely the hippocampus, the amygdala, the thalamus and the hypothalamus. Remarkably, subsequent work indicated that neurons but not endothelial cells are the main reservoir of tPA in the central nervous system, and that in the brain tPA has many functions that do not require PLG as a substrate. Interestingly, while most of the studies on neuronal tPA have been performed either with cells cultured from the hippocampus or with hippocampal slices, fewer have investigated whether tPA has a function in cerebral cortical neurons. Research from our laboratory has found that in the cerebral cortex tPA is expressed mainly in axons from clusters of parvalbumin-positive neurons, and that membrane depolarization induces the rapid release of this tPA. To further characterize the axonal expression of tPA, wild-type cerebral cortical neurons were co-stained with antibodies against tPA and bassoon, a protein abundantly expressed in the presynaptic terminal. These studies revealed that approximately one-third of all axonal tPA is found in the axonal bouton. Remarkably, this proportion remained constant throughout all examined axons, suggesting the presence of a mechanism that regulates the translocation of tPA from the axonal shaft into the presynaptic terminal. In summary, the available data indicate that tPA plays a central role as a regulator of synaptic function. According to this model, the release of tPA from cerebral cortical neurons has a neuromodulatory effect on presynaptic function by inducing the anatomical and biochemical changes in the synaptic release site required for the release of excitatory neurotransmitters. Further studies are needed to understand whether this effect requires a receptor for tPA on the surface of the presynaptic terminal.

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    Dopamine regulation of striatal inhibitory transmission and plasticity: dopamine, low or high?
    Elizabeth Hernández-Echeagaray
    2016, 11 (2):  214-214.  doi: 10.4103/1673-5374.177715
    Abstract ( 242 )   PDF (130KB) ( 454 )   Save

    The striatum is the principal input nuclei to the BG and the DA through direct action of the nigrostriatal system on striatal synapses, selects and modulates learned motor programs. Modulatory actions of DA on Medium Spiny Neurons (MSNs) are very well described in relation to corticostriatal connection and glutamatergic release. Even the importance of cortical influences on MSN, there are other neuronal subtypes inside of the striatum, which establish connection with MSN and form the local circuits. GABAergic synaptic inputs to MSNs come from axonal collaterals of other MSNs, as well as, from interneurons, this synaptic influences shape MSNs activity, and both are modulated by DA. We have recently published that the net modulatory effect of DA on inhibitory synapses that GABAergic interneuron’s made on MSNs, is a decrease in the amplitude of the inhibitory postsynaptic current (IPSC). However the long term plasticity induced in this synapses (GABAergic interneuron’s-MSNs) depends on the DA concentration in addition to the activation of D1 or D2 receptors subtype. High Frequency Stimulation (HFS) in low DA concentration (200 nM) produced mostly LTD, whereas high concentration of DA (20 µM) favored the generation of LTP.

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    Gas6-Tyro3 signaling is required for Schwann cell myelination and possible remyelination
    Tomohiro Torii, Junji Yamauchi
    2016, 11 (2):  215-216.  doi: 10.4103/1673-5374.177714
    Abstract ( 171 )   PDF (345KB) ( 468 )   Save

    Myelin plays important roles in vertebrates, ensuring the rapid propagation of action potentials and the long-term integrity of axons, but the molecular mechanisms of myelin formation remain poorly understood. Recent studies have demonstrated that myelination is regulated by the TAM family of enzymes, which consists of Tyro3 (also known as Brt, Dtk, Rse, Sky, and Tif), Axl (also known as Ark, Tyro7, and Ufo), and Mer (also known as Eyk, Nym, and Tyro12) along with its ligand growth arrest-specific gene 6 (Gas6). The three TAMs are also expressed in the brain during postnatal development, specifically, in the white matter, which consists of myelinated axons (Prieto et al. 2000). These studies are helping to identify the signals that are associated with myelination in oligodendrocytes and Schwann cells. It is well established that TAMs control inflammatory responses, cell proliferation, cell survival, and phagocytosis in cells of various types. As their endogenous ligands, the TAMs recognize protein S (PROS1) and Gas6, both of which are widely expressed in the central nervous system (CNS) after birth. Interestingly, recent works have explained that Gas6 signaling controls oligodendrocyte survival through phosphatidylinositol 3-kinase (PI3-kinase) and upregulates the expression of 2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNPase), which is known as a marker for oligodendrocyte and myelin. It also plays an important role in oligodendrocyte myelination. These findings indicate that the TAM-Gas6 signaling pathway promotes the myelination of oligodendrocytes in the nervous system as well as supporting immune responses. Moreover, Gas6 also promotes the remyelination of oligodendrocytes after cuprizone-induced injury and is necessary for oligodendrocyte survival. Taken together, these findings demonstrate that the TAM-Gas6 signaling pathway plays an important role in myelination/remyelination and demyelination by oligodendrocytes in the CNS. Yet the molecular mechanisms operating within this pathway and underlying the myelin formation process during development remain largely unknown. This review summarizes recent developments in our understanding of the necessity of Gas6-stimulated Tyro3 activation for Schwann cell myelination and/or remyelination.

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    Polyethylene glycol-fusion retards Wallerian degeneration and rapidly restores behaviors lost after nerve severance
    George D. Bittner,Michelle Mikesh, Cameron L. Ghergherehchi
    2016, 11 (2):  217-219.  doi: 10.4103/1673-5374.177716
    Abstract ( 251 )   PDF (600KB) ( 376 )   Save

    While the specific mechanisms responsible for retarding Wallerian degeneration and rapidly restoring behaviors lost after complete axonal severance of peripheral nerves are not yet known, PEG-fusion may translate well to clinical procedures since all drugs are benign, readily available, and are already FDA-approved for human use. Successful allograft repair suggests that tissue banks might consider the inclusion of donor nerve tissue alongside donor corneas, livers, hearts, etc. This PEG-fusion technology developed to restore many behaviors lost after peripheral nerve severance or ablation has also recently been reported to restore many behaviors lost after spinal contusion injuries.

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    Effects of chemical and physical cues in enhancing neuritogenesis and peripheral nerve regeneration
    Casey D. Sigerson, Christopher J. Dipollina, Michele Fornaro
    2016, 11 (2):  220-221.  doi: 10.4103/1673-5374.177717
    Abstract ( 177 )   PDF (256KB) ( 445 )   Save

    Developing a model that incorporates several of the relevant factors would be of great interest to the field of neuroregeneration. The creation of microenvironments that simultaneously address topography, bound ECM cues and free neurotrophic factors would allow researchers to test for possible additive or synergistic effects due to the combination of factors. Only myriad combinations of biophysical and biochemical cues will allow neuroscientists to elucidate the optimal environment for neuroregeneration. Discoveries in the area of in vitro regeneration will lead to the most important goal for this field of research: the modification of the neural microenvironment in vivo to promote axonal growth and restore neural function.

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    New insight into curcumin-based therapy in spinal cord injuries: CISD2 regulation
    Chai-Ching Lin, Muh-Shi Lin
    2016, 11 (2):  222-223.  doi: 10.4103/1673-5374.177718
    Abstract ( 248 )   PDF (233KB) ( 427 )   Save

    CDGSH iron sulfur domain 2 (CISD2) (synonyms: NAF-1, Eris, Miner1 and Noxp70) was originally regarded as a survival gene, based on its roles in calcium metabolism, anti-apoptosis, and longevity. Furthermore, CISD2 has been shown to inhibit an increase in excitotoxic Ca2+ at the endoplasmic reticulum, via a combination between BCL2 and the inositol 1,4,5-triphosphate receptor. CISD2 helps to prevent mitochondrial dysfunction and subsequent cell death. Our research team also found that CISD2 plays a moderating role in traumatic spinal cord injuries. The authors previously identified the injury-induced down-regulation of CISD2 expression in an animal model of SCI as well as in a cell culture model of astrocyte reactivation. Using primary impact and hemisection to adjust injury severity, animals subjected to SCI presented a signi?cant upregulation of proin?ammatory mediators, including inducible nitric oxide synthase (iNOS) and RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) as well as a downregulation of CISD2 mRNA and protein expression. It has been postulated that SCI causes inflammatory responses and a drop in CISD2 levels. Furthermore, CISD2 inactivity has been proposed as a mechanism underlying secondary damage following SCI. Curcumin exhibits multiple pharmacologic effects, such as anti-in?ammatory, anticarcinogenic, anti-infection, antioxidant, and hypocholesterolemic activities. The neuroprotective benefits stemming from the anti-inflammatory effects of curcumin have been demonstrated in cases of SCI. The pharmacological effects of curcumin clearly involve the regulation of CISD2. Briefly, injury to the spinal cord downregulates the expression of CISD2; however, curcumin has been shown to attenuate the downregulation of CISD2 in SCI and LPS-treated astrocytes. The ability of curcumin to prolong the expression of CISD2 could be of therapeutic value in SCI therapy. The anti-apoptosis and attenuation of NO production by CISD2 may account for the neuroprotective effects of curcumin in the treatment of SCI.

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    Manipulating extrinsic and intrinsic obstacles to axonal regeneration after spinal cord injury
    Eugene Mironets, Di Wu, Veronica J. Tom
    2016, 11 (2):  224-225.  doi: 10.4103/1673-5374.177719
    Abstract ( 197 )   PDF (835KB) ( 350 )   Save

    Spinal cord injury (SCI) is a traumatic event that can lead to permanent motor and sensory deficits. After the initial trauma, axons of surviving neurons rapidly retract. While there may be a small degree of abortive sprouting, virtually all attempts at robust regrowth across the lesion site ultimately fail. Thus, neurons below the level of the injury are permanently disconnected from their normal input, resulting in persistent loss of function.  Recently, several labs have begun to elucidate what factors may mediate the intrinsic, growth deficiency in mature CNS neurons. Interestingly, increasing levels of several developmentally-regulated transcription factors, such as several members of the Krüppel-like factor (KLF) family and Sox11, in adult neurons improves their ability to re-grow or sprout. Elegant work by Zhigang He and colleagues showed that the tumor suppressor PTEN (phosphatase and tensin homolog), is upregulated in mature neurons. PTEN inhibits the activation of the protein synthesis regulator mTOR (mammalian target of rapamycin). MTOR activation increases the synthesis of proteins that are associated with growth and survival. Moreover, genetic deletion of PTEN increases mTOR activation and results in substantial axon growth after injury. However, while this approach addresses the intrinsic limitations to growth after injury, the inhibitory barriers within the glial scar remain intact. Recently, we hypothesized that simultaneously addressing intrinsic neuronal deficits in axon regrowth and extrinsic, scar-associated impediments to regeneration would result in significant regeneration after SCI. We grafted PN into the complete, thoracic level SCI to provide a growth-promoting environment to span the cavity. We injected adeno-associated virus (AAV) encoding for green fluorescent protein (GFP; control vector) or constitutively active Rheb (caRheb; Ras homolog enriched in brain) rostral to the lesion to transduce and drive mTOR activation in neurons above the SCI. Lastly, we treated the distal graft-host interface with ch’ase to diminish the effects of the inhibitory extracellular matrix in the glial scar. Because multiple facets will need to be considered to achieve functional repair of the SCI, combinatorial strategies focused on manipulate intrinsic neuronal growth potential while simultaneously reducing the extrinsic inhibitors of axon extension will likely be a staple for future therapies in SCI.

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    Consequences of hepatic damage after traumatic brain injury: current outlook and potential therapeutic targets
    Sonia Villapol
    2016, 11 (2):  226-227.  doi: 10.4103/1673-5374.177720
    Abstract ( 213 )   PDF (372KB) ( 389 )   Save

    Traumatic brain injury (TBI) is a serious pathology affecting around 10 million people annually, being a persistent public health and medical problem. Although TBI has long term consequences due to the immediate loss of brain tissue, treatment has focused on mitigating secondary damage. Yet there exist more that 30 clinical trials for TBI that fail despite successful experimental data. Most of these studies were based on neuroprotective treatments to reduce inflammation and neurodegeneration in the injured brain, with consequent the motor and cognitive improvements. However, injury to the brain also produces alterations in the bloodstream and peripheral organs. Recent breakthroughs in brain injury research investigate the link between brain inflammation and peripheral organs; and one of the most sensitive organs to inflammation is the liver. The systemic production of cytokines and chemokines by the liver and other organs, in response to the brain damage, is an essential factor of the inflammatory secondary response in the brain due to communication of brain-periphery. Recent studies have demonstrated that focal injury to the brain elicits a rapid hepatic response, the production of chemokines by the liver acts as an amplifier of the focal injury response providing a route of CNS-liver communication. The blockade of inflammatory intermediaries of the liver after brain injury can effectively alter the recruitment of leukocytes to the brain, an important factor to consider when peripheral inflammation exacerbates the progression of brain damage. As an acute phase protein with pleiotropic pro-inflammatory properties, SAA may represent an important link between brain injury and hepatic and systemic inflammation. Yet, there is also evidence to suggest that systemic inflammation confers a degree of tolerance to brain injury. Like the liver, other secondary organs damaged by similar pathologies observed in patients with acute brain injury may also represent alternative therapeutic targets for improving clinical outcome. In conclusion, since inflammation appears to be a common link between brain injury and the periphery, one is led to hypothesize that inflammatory signals released after TBI could regulate components of hepatic response and that consequently induce detrimental changes damaged brain regions.

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    Advances in minimally invasive treatment of hemorrhagic and ischemic stroke
    Robert C. Rennert, J. Scott Pannell, Alexander A. Khalessi
    2016, 11 (2):  228-229.  doi: 10.4103/1673-5374.177747
    Abstract ( 195 )   PDF (831KB) ( 587 )   Save

    Cerebrovascular diseases, including ischemic and hemorrhagic strokes, affect more than 6 million US adultsannually. Strokes cause high rates of morbidity and mortality due to the central nervous system’s sensitivity to disruptions in blood flow, and are refractory to traditional surgical interventions. A variety of minimally invasive surgical and endovascular approaches have recently been developed to improve outcomes patient outcomes following stroke. As research in other surgical fields has demonstrated multiple advantages of minimally invasive techniques, including avoidance of large incisions requiring less sedation, less trauma to the patient, and potentially lower treatment costs resulting from shorter hospital courses and a reduced need for post-operative intensive medical care, it is no surprise that minimally invasive surgical approaches to stroke have recently gained traction. As highlighted herein, the successful development and integration of such technology requires a strong pre-clinical foundation and well designed clinical trials. The promising results in the aforementioned and ongoing clinical trials suggest the future utilization of minimally invasive techniques for the treatment of hemorrhagic and ischemic stroke will continue to increase.

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    Tenascin-C in aneurysmal subarachnoid hemorrhage: deleterious or protective?
    Hidenori Suzuki, Fumihiro Kawakita
    2016, 11 (2):  230-231.  doi: 10.4103/1673-5374.177721
    Abstract ( 349 )   PDF (168KB) ( 447 )   Save

    Subarachnoid hemorrhage (SAH) caused by the rupture of a cerebral aneurysm is a well-known devastating cerebrovascular disease. Post-SAH brain is vulnerable, associated with early brain injury. The first step for intensive care of aneurysmal SAH patients is aneurysmal obliteration to prevent rebleeding as well as further aggravation of EBI. The subsequent treatment requires intensive medical care to manage the associated problems including hydrocephalus, cerebral vasospasm and delayed cerebral ischemia (DCI). Despite improvements in the clinical management of SAH, DCI remains one of the most important causes of morbidity and mortality in SAH patients who survive the initial bleeding. Recently, EBI as well as cerebral vasospasm is considered to be a cause of DCI (Suzuki, 2015). However, the pathogenesis of EBI, cerebral vasospasm and DCI remains unclear, precluding the development of new therapies against them.

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    ERp57 in neurodegeneration and regeneration
    Leslie Bargsted, Claudio Hetz, Soledad Matus
    2016, 11 (2):  232-233.  doi: 10.4103/1673-5374.177722
    Abstract ( 310 )   PDF (282KB) ( 464 )   Save

    The protein disulfide isomerases (PDIs) family has a central function in the folding of proteins synthetized through the secretory pathway. ERp57, also known as Grp58 or PDIA3, is one of the main studied members of this family. ERp57 catalyzes the formation, disruption and isomerization of disulfide bonds of glycoproteins mediated by a cooperative interaction with the endoplasmic reticulum (ER) chaperones calnexin and calreticulin. In the past years, several studies have linked ERp57 and its closest homologue PDI (also known as PDIA1) to diseases affecting the central nervous system, including amyotrophic lateral sclerosis, Parkinson’s disease, Alzheimer’s disease, among others. These neurodegenerative conditions are characterized by the presence of abnormal protein aggregates containing specific proteins, which are now classified as protein misfolding disorders (PMDs). The available evidence is depicting a novel scenario,
    placing PDIs as interesting targets for disease intervention. Due to the fact synaptic dysfunction are salient features of most neurodegenerative conditions, the possible consequences of enforcing ERp57 expression in the brain (i.e., using gene therapy) should be explored as a strategy to improve neuronal survival, synaptic function, and enhance tissue regeneration where ERp57 could act over protein substrates involved in synaptic functions. It remains to be elucidated if other functions beyond the ER can be attributed to the beneficial effects of ERp57 expression. Of note, ERp57 has been described in subcelular localizations beyond the ER, including the nucleus, the plasma membrane and cytoplasm (Turano et al., 2002). The new mouse models generated to manipulate ERp57 levels in the nervous system represent relevant tools to assess the function of this foldase to diverse diseases. Since the PDI family of proteins
    involves more than 20 members, we predict that this field will accelerate and develop toward the identification of novel functions of PDIs and other components of the ER proteostasis network on a variety of pathologies involving altered function of the secretory pathway.

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    Synthetic cell pathobiology to study neurodegeneration: defining new therapeutic targets in astroglia
    Matjaž Stenovec, Robert Zorec
    2016, 11 (2):  234-235.  doi: 10.4103/1673-5374.177723
    Abstract ( 163 )   PDF (259KB) ( 421 )   Save

     Experiments on 3xTg-AD mouse astrocytes, devoid of their pathologic environment, revealed, for the first time, that the expression of mutated presenilin 1 (PS1M146V) differentially alters the dynamics of different vesicle types, which may contribute to the development of AD (Stenovec et al., 2016). The same experimental approach, however, is not possible in humans. Here, the use of iAstrocytes represents the major technological advancement and the only acceptable alternative to experimentally address the early dysfunction in cultured astroglial cells converted from fibroblast of diseased (and healthy) members of families with medical history of neurodegenerative diseases. Human iAstrocytes can be further used to develop a new diagnostic test based on analysis of vesicle mobility, which may aid predict the clinical manifestation of the disease already in the early, pre-symptomatic phase of disease. Thus, the synthetic pathobiology approach, where cell-reprogramming technology is used to convert embryonic, postnatal or adult fibroblasts, isolated from a patient, into induced astrocytes (iAstrocytes), appears to be a promising strategy to identify new mechanisms and targets in astroglia associated with neurodegeneration, such as AD.

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    The neuroprotective effects of the anti-diabetic drug linagliptin against Aβ-induced neurotoxicity
    Chih-Li Lin, Chien-Ning Huang
    2016, 11 (2):  236-237.  doi: 10.4103/1673-5374.177724
    Abstract ( 154 )   PDF (386KB) ( 413 )   Save

    Impaired insulin signaling is defined as a reduced response to insulin stimulation. In vertebrates, almost all cell types are responsive to insulin signaling. Impaired insulin signaling, also called as insulin resistance, is a central characteristic feature to develop the metabolic syndrome including diabetes, cardiovascular disease, cancer, and other life-threatening disorders. However, there is increasing evidence that insulin resistance itself may affect central nervous system (CNS) functions. Particularly, impaired insulin signaling in the brain has been linked to AD, the most common type of dementia. AD is more broadly defined to include the pathogenic mechanisms underlying amyloid β (Aβ)-induced neurotoxicity. Interestingly, increasing evidence suggests defective brain insulin signaling may play a key role in AD pathogenesis. Brain insulin resistance in AD was firstly proposed about two decades ago. In 1994, Hoyer et al. hypothesized that neuronal insulinin sensitivity may explain reduced brain metabolism in such neurodegenerative disorder. Although the detailed mechanism of the brain insulin resistance is uncertain, a serial studies reported significantly decreased neuronal insulin signaling in the neocortex and hippocampus of AD cases. GLP-1 is produced in the brain mediating many neuronal functions, including neuroprotection, improvement of learning and memory ability, and potentiation of insulin signaling. This indicates GLP-1 may display the potential to serve as therapeutic or preventive strategies against diabetes-related AD. As DPP-4 inhibitors can effectively increase GLP-1 levels, they may also exert protective effects against AD-related neurodegeneration.
    It is known the proglucagon gene encodes GLP-1 peptides, which is located on the long arm of human chromosome 2 with the entire coding sequence within exon 4. In past years, GLP-1 peptide is thought to be mainly expressed in the pancreas α cells and intestine L-cells. However, mammalian GLP-1gene is now known to be actively transcribed in brain neurons. Such evolutionary correlations may provide important clues of insulin signaling in the brain neuronal functions. Accordantly, GLP-1 signaling is known to modulate many neuronal functions in the brain; therefore, GLP-1 signaling have demonstrated the potential to serve as therapeutic or preventive strategies against diabetes-related AD. Considering the important roles of the Aβ-induced oxidative stress in AD pathogenesis, our research unveils a potential neuroprotective mechanism by linagliptin through suppressing oxidative damage and preserving mitochondria function via restoration of neuronal insulin signaling.

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    Endoproteolytic cleavage as a molecular switch regulating and diversifying prion protein function
    Cathryn L. Haigh, Steven J. Collins
    2016, 11 (2):  238-239.  doi: 10.4103/1673-5374.177726
    Abstract ( 198 )   PDF (377KB) ( 445 )   Save

    The prion protein (PrP), through misfolding, is widely known for its causative role in prion diseases, which are transmissible neurodegenerative diseases of humans and animals. There is still no defined function assigned to PrP, especially in the central nervous system, despite many studies in this area. Proposed functions are protean and include signal transduction, neuroprotection, neurogenesis, neuritogenesis, metal-ion homeostasis, memory formation and consolidation, as well as circadian rhythms. Part of the difficulty in assigning aspecific function to PrP could perhaps be that it does not have one single function. Instead it might be able to perform many functions and influence various pathways depending upon contextual post-translational modification. Recently a further cleavage event has been extensively characterised. Referred to as “gamma-cleavage”, this event occurs in the C-terminal structured domain and therefore produces fragments with very different features to both the α- and β-cleavages. A functional significance is yet to be assigned to this processing event, but its presence in multiple cells and tissues, and in disease, suggests that the fragments produced are likely toexert cellular effects distinct to that produced by the other PrP constitutive processing events. The precise cellular locations of the cleavage events and of the resulting fragments, whether processing occurs at the cell surface and whether N-terminal fragments act in cis or trans, the enzymes controlling these events, the membrane micro-milieuand dynamic rather than absolute cleavage levels may all potentially impact functional consequences. Until the various nuances of combined post-translational modifications of PrP coupled with cleavage events in different contexts and in different tissues are fully elucidated, PrP appears destined to remain an enigmatic “actor” playing in many apparent functional roles.

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    New insights into the functions of PtdIns(3,5)P2 in the pathogenisis of neurodegenerative disorders
    Fuminori Tsuruta
    2016, 11 (2):  240-241.  doi: 10.4103/1673-5374.177727
    Abstract ( 276 )   PDF (326KB) ( 330 )   Save

    The membrane trafficking system plays an important role in the nervous system. Some membrane proteins are removed from the plasma membrane by incorporation into endocytic structures, which become early endosomes. Next, these proteins are sorted into the luminal space by invagination of the endosomal limiting membrane, leading to the formation of multivesicular bodies (MVBs). MVBs are morphologically distinct from late endosomes that internally accumulate small membrane vesicles containing the cargo proteins. The formation of MVBs is catalyzed by the Endosomal sorting complex required for transport (ESCRT) complexes, ESCRT-I, ESCRT-II, and ESCRT-III. These complexes form a network that recruits mono-ubiquitinated proteins and drives their internalization into luminal vesicles of MVBs. Finally the fusion of MVBs with lysosomes delivers internal vesicles and cargo proteins into the lysosomal lumen, where they are degraded by lysosomal proteases and lipases. Since the membrane trafficking system is essential for the regulation of morphology, development, and survival of neurons, studies in this field give useful insights that contribute to our understanding of the brain. Recently, we have reported a novel mechanism that underlie PtdIns(3,5)P2 functions in neurons. Previously, we reported that PIKfyve-produced PtdIns(3,5)P2 play important roles in the protection of excitotoxic cell death via regulation of voltage-gated calcium channel, CaV1.2 expression. In neurons, intracellular Ca2+ concentration is an important factor to coordinate neuronal activity. Indeed, our studies have shown that bath glutamate application promotes the internalization of CaV1.2 from the plasma membrane, leading to lysosomal degradation. As many neurodegenerative disorders are implicated in both membrane trafficking and Ca2+ homeostasis, the mechanisms identified in our study may provide an important clue of why perturbed PtdIns(3,5)P2 metabolism causes neurodegeneration such as ALS and Charcot-Marie-Tooth disease.
    In conclusion, our recent study has reported that PIKfyve mediates endolysosomal motility in neurons. PtdIns(3,5)P2 play important roles in a variety of cellular functions. It is also known that dysregulation of PtdIns(3,5)P2 metabolism causes neuromuscular disorders such as Charcot-Marie-Tooth disease and ALS. Thus, our finding shed light on a novel function of PtdIns(3,5)P2 and provide an important clue that links perturbed PtdIns(3,5)P2 metabolism to neurodegenerative disorders.

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    Tetrahydrohyperforin (IDN5706) targets the endoplasmic reticulum for autophagy activation: potential mechanism for Alzheimer’s disease therapy
    Alexis González, Viviana A. Cavieres, Nibaldo C. Inestrosa,Patricia V. Burgos
    2016, 11 (2):  242-243.  doi: 10.4103/1673-5374.177728
    Abstract ( 268 )   PDF (582KB) ( 475 )   Save

    To date, there is no therapy to stop the destruction of brain cells and all the available treatments only compensate for the loss of synaptic transmission, thus resulting in marginal benefits to patients. Therefore, there is an urgent need to find effective therapies that prevent or slow down the progression of this major public health problem. To prevent brain cell loss, we need to identify and understand the exact causes of the disease. In the present perspective, we propose that positive regulators of ER autophagy-related responses, such as tetrahydrohyperforin, are promising niches for the discovery of future therapies against AD. A recent study published by our group using a neuroprotective semisynthetic derivative of hyperforin, the active molecule in the St John´s Wort plant (Hypericum perforatum) called tetrahydrohyperforin (IDN5706), has demonstrated that this compound prevents the neuropathological changes in a mouse model of AD. Specifically, it induces long-term potentiation (LTP) and prevents AD-associated loss of spatial memory, reduces tau hyperphosphorylation, and decreases Abeta peptide levels. In an effort to elucidate the molecular mechanism that could explain the beneficial effects of this compound, we recently showed that IDN5706 targets the ER for autophagy activation, triggering entry of immaturely glycosylated, newly-synthesized APP (iAPP) in ER-associated structures, which favors its degradation by Atg5-dependent autophagy, leading to inhibition of Abeta peptide formation. Autophagy, a major lysosomal degradative pathway, has been extensively studied in age-related neurodegenerative disorders, such as AD, due to its strong connection between aging and the progressive deterioration in the proteostatic capacity of the brain. Although, several studies indicate that induction of autophagy delays aging, reducing the risk of neurodegenerative disorders and neuronal dysfunction in animal models, the underlying mechanisms still remain poorly understood. In this context, our recent findings with the neuroprotective compound IDN5706 revealed that the ER could be a major regulator for autophagy activation, necessary to promote the clearance of APP upon perturbations in its glycosylation, strongly supporting the hypothesis that autophagy could play a key role in quality control at the ER.

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    Finding chemopreventatives to reduce amyloid beta in yeast
    Ian G. Macreadie, Costa Arvanitis, Prashant Bharadwaj
    2016, 11 (2):  244-245.  doi: 10.4103/1673-5374.177729
    Abstract ( 223 )   PDF (256KB) ( 519 )   Save

    The 42 amino acid peptide known as amyloid beta (or Aβ) has been implicated as the most likely causative agent of AD since its discovery in plaques in 1985. Since then evidence has accumulated to support the association between AD and amyloid beta. However, progress to find a cure for AD has been very slow, due to lack of reliable models and a lack of understanding about what role amyloid beta plays in AD. The failure to cure AD led many to doubt that amyloid beta should be the prime target for the treatment of AD, resulting in a backlash against research on amyloid beta as a drug target. The recent antibody trial is showing some promise, although it did not meet the desired end points. There is growing interest in naturally derived compounds as chemo preventatives to remove amyloid beta. Such compounds should be taken conveniently, which means it is best if they can be ingested. Epidemiology suggests there are many compounds in existing foods that may be useful for chemo prevention of AD. Since we have reasonable ideas about the molecular basis of amyloid beta it is important that we incorporate these ideas into rationale screening for AD chemo preventatives. The ability of yeast to be used as a tool for screening anti amyloidogenic compounds is a useful and unique contribution. It can be adapted to high throughput use, it informs about compounds that are bioavailable, and it requires no amyloid beta preparation. In a world that seeks new ways to lower amyloid beta, the yeast assays should be valuable additions to moving forward.

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    The inherent high vulnerability of dopaminergic neurons toward mitochondrial toxins may contribute to the etiology of Parkinson’s disease
    Kandatege Wimalasena
    2016, 11 (2):  246-247.  doi: 10.4103/1673-5374.177730
    Abstract ( 254 )   PDF (451KB) ( 437 )   Save

    Although the exact mechanism(s) of the degeneration of dopaminergic neurons in PD is not well understood, mitochondrial dysfunction is proposed to play a central role. This proposal is strongly strengthened by the findings that compromised mitochondrial functions and/or exposure to mitochondrial toxins such as rotenone, paraquat, or MPTP causes degeneration of the mid brain dopaminergic system and manifest symptoms similar to Parkinson’s in primates and rodents. In fact, the specific dopaminergic toxin MPTP is one of the most commonly used models in the mechanistic studies of environmental factors associated with the etiology of PD, particularly due to the availability of direct and unequivocal clinical and biochemical evidence from human and primate subjects. Several decades of intense studies in many laboratories have led to a general mechanism for thespecific dopaminergic toxicity of MPTP. The salient features of this mechanism are (a) lipophilic pro-toxin MPTP freely crosses the blood brain barrier and enters the brain; (b) in glial cells monoamine oxidase-B converts it to the terminal toxin MPP+; (c) the polar MPP+ is extruded into the extracellular space through organic cation transporter-3; (d) presynaptic dopamine transporter (DAT) takes it upspecifically into dopaminergic neurons; (e) in dopaminergic neurons, MPP+ accumulates in the synaptic vesicles and/or mitochondria; (f) mitochondrial MPP+ inhibits the mitochondrial complex-I of the electron transport chain leading to cellular ATP depletion and excessive ROS production causing apoptotic cell death. Although this mechanism is generally well accepted, numerous recent studies seriously challenge the central dogma of this proposal that the specific dopaminergic toxicity of MPP+ is primarily due to the specific uptake into dopaminergic neurons through presynaptic DAT.

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    Automated monitoring of early neurobehavioral changes in mice following traumatic brain injury
    Wenrui Qu, Nai-kui Liu, Xin-min (Simon) Xie, Rui Li, Xiao-ming Xu
    2016, 11 (2):  248-256.  doi: 10.4103/1673-5374.177732
    Abstract ( 236 )   PDF (3652KB) ( 724 )   Save

    Traumatic brain injury often causes a variety of behavioral and emotional impairments that can develop into chronic disorders. Therefore, there is a need to shift towards identifying early symptoms that can aid in the prediction of traumatic brain injury outcomes and behavioral
    endpoints in patients with traumatic brain injury after early interventions. In this study, we used the SmartCage system, an automated quantitative approach to assess behavior alterations in mice during an early phase of traumatic brain injury in their home cages. Female C57BL/6 adult mice were subjected to moderate controlled cortical impact (CCI) injury. The mice then received a battery of behavioral assessments including neurological score, locomotor activity, sleep/wake states, and anxiety-like behaviors on days 1, 2, and 7 after CCI. Histological analysis was performed on day 7 after the last assessment. Spontaneous activities on days 1 and 2 after injury were significantly decreased in the CCI group. The average percentage of sleep time spent in both dark and light cycles were significantly higher in the CCI group than in the sham group. For anxiety-like behaviors, the time spent in a light compartment and the number of transitions between the dark/light compartments were all significantly reduced in the CCI group than in the sham group. In addition, the mice suffering from CCI exhibited a preference of staying in the dark compartment of a dark/light cage. The CCI mice showed reduced neurological score and histological abnormalities, which are well correlated to the automated behavioral assessments. Our findings demonstrate that the automated SmartCage system provides sensitive and objective measures for early behavior changes in mice following traumatic brain injury.

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    Pulsed arterial spin labeling effectively and dynamically observes changes in cerebral blood flow after mild traumatic brain injury
    Shu-ping Peng, Yi-ning Li, Jun Liu, Zhi-yuan Wang, Zi-shu Zhang, Shun-ke Zhou, Fang-xu Tao, Zhi-xue Zhang
    2016, 11 (2):  257-261.  doi: 10.4103/1673-5374.177733
    Abstract ( 455 )   PDF (519KB) ( 446 )   Save

    Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies.
    However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient’s condition and judging prognosis after traumatic brain injury.

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    Let-7a gene knockdown protects against cerebral ischemia/reperfusion injury
    Zhong-kun Wang, Fang-fang Liu, Yu Wang, Xin-mei Jiang, Xue-fan Yu
    2016, 11 (2):  262-269.  doi: 10.4103/1673-5374.177734
    Abstract ( 265 )   PDF (1268KB) ( 467 )   Save

    The microRNA (miRNA) let-7 was one of the first miRNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1 (MKP1) is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.

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    Neuroprotection of Chrysanthemum indicum Linne against cerebral ischemia/reperfusion injury by anti-inflammatory effect in gerbils
    Ki-Yeon Yoo, In Hye Kim, Jeong-Hwi Cho, Ji Hyeon Ahn, Joon Ha Park, Jae-Chul Lee, Hyun-Jin Tae, Dae Won Kim,Jong-Dai Kim, Seongkweon Hong, Moo-Ho Won, Il Jun Kang
    2016, 11 (2):  270-277.  doi: 10.4103/1673-5374.177735
    Abstract ( 156 )   PDF (2031KB) ( 449 )   Save

    In this study, we tried to verify the neuroprotective effect of Chrysanthemum indicum Linne (CIL) extract, which has been used as a botanical drug in East Asia, against ischemic damage and to explore the underlying mechanism involving the anti-inflammatory approach. A gerbil was given CIL extract for 7 consecutive days followed by bilateral carotid artery occlusion to make a cerebral ischemia/reperfusion model. Then, we found that CIL extracts protected pyramidal neurons in the hippocampal CA1 region (CA1) from ischemic damage using neuronal nucleus immunohistochemistry and Fluoro-Jade B histofluorescence. Accordingly, interleukin-13 immunoreactivities in the CA1 pyramidal neurons of CIL-pretreated animals were maintained or increased after cerebral ischemia/reperfusion. These findings indicate that the pre-treatment of CIL can attenuate neuronal damage/death in the brain after cerebral ischemia/reperfusion via an anti-inflammatory
    approach.

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    Radix Ilicis Pubescentis total flavonoids combined with mobilization of bone marrow stem cells to protect against cerebral ischemia/reperfusion injury
    Ming-san Miao, Lin Guo, Rui-qi Li, Xiao Ma
    2016, 11 (2):  278-284.  doi: 10.4103/1673-5374.177736
    Abstract ( 147 )   PDF (1964KB) ( 714 )   Save

    Previous studies have shown that Radix Ilicis Pubescentis total flavonoids have a neuroprotective effect, but it remains unclear whether Radix Ilicis Pubescentis total flavonoids have a synergistic effect with the recombinant human granulocyte colony stimulating factor-mobilized bone marrow stem cell transplantation on cerebral ischemia/reperfusion injury. Rat ischemia models were administered 0.3, 0.15 and 0.075 g/kg Radix Ilicis Pubescentis total flavonoids from 3 days before modeling to 2 days after injury. Results showed that Radix Ilicis Pubescentis total flavonoids
    could reduce pathological injury in rats with cerebral ischemia/reperfusion injury. The number of Nissl bodies increased, Bax protein expression decreased, Bcl-2 protein expression increased and the number of CD34-positive cells increased. Therefore, Radix Ilicis Pubescentis total flavonoids can improve the bone marrow stem cell mobilization effect, enhance the anti-apoptotic ability of nerve cells, and have a neuroprotective
    effect on cerebral ischemia/reperfusion injury in rats.

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    Tongguan Liqiao acupuncture therapy improves dysphagia after brainstem stroke
    Chun-hong Zhang, Jin-ling Bian, Zhi-hong Meng, Li-na Meng, Xue-song Ren, Zhi-lin Wang, Xiao-yan Guo, Xue-min Shi
    2016, 11 (2):  285-291.  doi: 10.4103/1673-5374.177737
    Abstract ( 242 )   PDF (642KB) ( 468 )   Save

    Tongguan Liqiao acupuncture therapy has been shown to effectively treat dysphagia after stroke-based pseudobulbar paralysis. We presumed
    that this therapy would be effective for dysphagia after bulbar paralysis in patients with brainstem infarction. Sixty-four patients with dysphagia following brainstem infarction were recruited and divided into a medulla oblongata infarction group (n = 22), a midbrain and pons infarction group (n = 16), and a multiple cerebral infarction group (n = 26) according to their magnetic resonance imaging results. All patients received Tongguan Liqiao acupuncture for 28 days. The main acupoints were Neiguan (PC6), Renzhong (DU26), Sanyinjiao(SP6), Fengchi (GB20), Wangu (GB12), and Yifeng (SJ17). Furthermore, the posterior pharyngeal wall was pricked. Before and after treatment, patient swallowing functions were evaluated with the Kubota Water Test, Fujishima Ichiro Rating Scale, and the Standard Swallowing Assessment. The Barthel Index was also used to evaluate their quality of life. Results showed that after 28 days of treatment, scores on the Kubota Water Test and Standard Swallowing Assessment had decreased, but scores on the Fujishima Ichiro Rating Scale and Barthel Index had increased in each group. The total efficacy rate was 92.2% after treatment, and was most obvious in patients with medulla oblongata infarction (95.9%). These findings suggest that Tongguan Liqiao acupuncture therapy can repair the connection of upper motor neurons to the medulla oblongata motor nucleus, promote the recovery of brainstem infarction, and improve patient’s swallowing ability and quality of life.

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    Chinese preparation Xuesaitong promotes the mobilization of bone marrow mesenchymal stem cells in rats with cerebral infarction
    Jin-sheng Zhang, Bao-xia Zhang, Mei-mei Du, Xiao-ya Wang, Wei Li
    2016, 11 (2):  292-297.  doi: 10.4103/1673-5374.177738
    Abstract ( 209 )   PDF (1839KB) ( 707 )   Save

    After cerebral ischemia, bone marrow mesenchymal stem cells are mobilized and travel from the bone marrow through peripheral circulation to the focal point of ischemia to initiate tissue regeneration. However, the number of bone marrow mesenchymal stem cells mobilized into peripheral circulation is not enough to exert therapeutic effects, and the method by which blood circulation is promoted to remove blood stasis influences stem cell homing. The main ingredient of Xuesaitong capsules is Panax notoginseng saponins, and Xuesaitong is one of the main drugs used for promoting blood circulation and removing blood stasis. We established rat models of cerebral infarction by occlusion of the middle cerebral artery and then intragastrically administered Xuesaitong capsules (20, 40 and 60 mg/kg per day) for 28 successive days. Enzyme-linked immunosorbent assay showed that in rats with cerebral infarction, middle- and high-dose Xuesaitong significantly increased the level of stem cell factors and the number of CD117-positive cells in plasma and bone marrow and significantly decreased the number of CD54- and CD106-positive cells in plasma and bone marrow. The effect of low-dose Xuesaitong on these factors was not obvious. These findings demonstrate that middle- and high-dose Xuesaitong and hence Panax notoginseng saponins promote and increase the level and mobilization of bone marrow mesenchymal stem cells in peripheral blood.

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    Human neural stem cells promote proliferation of endogenous neural stem cells and enhance angiogenesis in ischemic rat brain
    Sun Ryu, Seung-Hoon Lee, Seung U. Kim, Byung-Woo Yoon
    2016, 11 (2):  298-304.  doi: 10.4103/1673-5374.177739
    Abstract ( 125 )   PDF (2075KB) ( 395 )   Save

    Transplantation of human neural stem cells into the dentate gyrus or ventricle of rodents has been reportedly to enhance neurogenesis. In this study, we examined endogenous stem cell proliferation and angiogenesis in the ischemic rat brain after the transplantation of human neural stem cells. Focal cerebral ischemia in the rat brain was induced by middle cerebral artery occlusion. Human neural stem cells were transplanted into the subventricular zone. The behavioral performance of human neural stem cells-treated ischemic rats was significantly improved and cerebral infarct volumes were reduced compared to those in untreated animals. Numerous transplanted human neural stem cells were alive and preferentially localized to the ipsilateral ischemic hemisphere. Furthermore, 5-bromo-2′-deoxyuridine-labeled endogenous neural stem cells were observed in the subventricular zone and hippocampus, where they differentiated into cells immunoreactive for the neural markers doublecortin, neuronal nuclear antigen NeuN, and astrocyte marker glial fibrillary acidic protein in human neural stem cells-treated rats, but not in the untreated ischemic animals. The number of 5-bromo-2′-deoxyuridine-positive ⁄ anti-von Willebrand factor-positive proliferating endothelial cells was higher in the ischemic boundary zone of human neural stem cells-treated rats than in controls. Finally, transplantation of human neural stem cells in the brains of rats with focal cerebral ischemia promoted the proliferation of endogenous neural stem cells and their differentiation into mature neural-like cells, and enhanced angiogenesis. This study provides valuable insights into the effect of human neural stem cell transplantation on focal cerebral ischemia, which can be applied to the development of an effective therapy for stroke.

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    Manual acupuncture at the SJ5 (Waiguan) acupoint shows neuroprotective effects by regulating expression of the anti-apoptotic gene Bcl-2
    Dong Lin, Li-li Lin, Kyle Sutherland, Chuan-hai Cao
    2016, 11 (2):  305-311.  doi: 10.4103/1673-5374.177740
    Abstract ( 182 )   PDF (1034KB) ( 411 )   Save

    Acupuncture at the SJ5 (Waiguan) acupoint has neuroprotective effects in cerebral infarction, but the underlying mechanism remains poorly understood. Here, we analyzed gene expression in healthy rat cerebellum using a pathway-focused DNA microarray to screen 113 genes associated with 18 signal transduction pathways. After 20 minutes of acupuncture at SJ5, the expression of Bcl-2 and Birc1b mRNA was markedly increased. This was confirmed by real-time reverse transcription PCR. Furthermore, western blot analysis showed that Bcl-2 protein expression remained high in the cerebellum until at least 2 hours after cessation of acupuncture. These findings indicate that acupuncture at SJ5 exerts neuroprotective effects by regulating the expression of anti-apoptotic gene Bcl-2.

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    Neural differentiation and synaptogenesis in retinal development
    Wen-juan Fan, Xue Li, Huan-ling Yao, Jie-xin Deng, Hong-liang Liu, Zhan-jun Cui, Qiang Wang, Ping Wu, Jin-bo Deng
    2016, 11 (2):  312-318.  doi: 10.4103/1673-5374.177743
    Abstract ( 233 )   PDF (2035KB) ( 397 )   Save

    To investigate the pattern of neural differentiation and synaptogenesis in the mouse retina, immunolabeling, BrdU assay and transmission electron microscopy were used. We show that the neuroblastic cell layer is the germinal zone for neural differentiation and retinal lamination. Ganglion cells differentiated initially at embryonic day 13 (E13), and at E18 horizontal cells appeared in the neuroblastic cell layer. Neural stem cells in the outer neuroblastic cell layer differentiated into photoreceptor cells as early as postnatal day 0 (P0), and neural stem cells in the inner neuroblastic cell layer differentiated into bipolar cells at P7. Synapses in the retina were mainly located in the outer and inner plexiform layers. At P7, synaptophysin immunostaining appeared in presynaptic terminals in the outer and inner plexiform layers with button-like structures. After P14, presynaptic buttons were concentrated in outer and inner plexiform layers with strong staining. These data indicate that neural differentiation and synaptogenesis in the retina play important roles in the formation of retinal neural circuitry. Our study showed that the period before P14, especially between P0 and P14, represents a critical period during retinal development. Mouse eye opening occurs during that period, suggesting that cell differentiation and synaptic formation lead to the attainment of visual function.

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    Ginsenoside Rg1 protects against neurodegeneration by inducing neurite outgrowth in cultured hippocampal neurons
    Liang Huang, Li-feng Liu, Juan Liu, Ling Dou, Ge-ying Wang, Xiao-qing Liu, Qiong-lan Yuan
    2016, 11 (2):  319-325.  doi: 10.4103/1673-5374.177741
    Abstract ( 314 )   PDF (621KB) ( 460 )   Save

    Ginsenoside Rg1 (Rg1) has anti-aging and anti-neurodegenerative effects. However, the mechanisms underlying these actions remain unclear. The aim of the present study was to determine whether Rg1 affects hippocampal survival and neurite outgrowth in vitro after exposure to amyloid-beta peptide fragment 25–35 (Aβ25–35), and to explore whether the extracellular signal-regulated kinase (ERK) and Akt signaling pathways are involved in these biological processes. We cultured hippocampal neurons from newborn rats for 24 hours, then added Rg1 to the medium for another 24 hours, with or without pharmacological inhibitors of the mitogen-activated protein kinase (MAPK) family or Akt signaling pathways for a further 24 hours. We then immunostained the neurons for growth associated protein-43, and measured neurite length. In a separate experiment, we exposed cultured hippocampal neurons to Aβ25–35 for 30 minutes, before adding Rg1 for 48 hours, with or without Akt or MAPK inhibitors, and assessed neuronal survival using Hoechst 33258 staining, and phosphorylation of ERK1/2 and Akt by western blot analysis. Rg1 induced neurite outgrowth, and this effect was blocked by API-2 (Akt inhibitor) and PD98059 (MAPK/ERK kinase inhibitor), but not by SP600125 or SB203580 (inhibitors of c-Jun N-terminal kinase and p38 MAPK, respectively). Consistent with this effect, Rg1 upregulated the phosphorylation of Akt and ERK1/2; these effects were reversed by API-2 and PD98059, respectively. In addition, Rg1 significantly reversed Aβ25–35-induced apoptosis; this effect was blocked by API-2 and PD98059, but not by SP600125 or SB203580. Finally, Rg1 significantly reversed the Aβ25–35-induced decrease in Akt and ERK1/2 phosphorylation, but API-2 prevented this reversal. Our results indicate that Rg1 enhances neurite outgrowth and protects against Aβ25–35-induced damage, and that its mechanism may involve the activation of Akt and ERK1/2 signaling.

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    Neuroprotective role of (Val8)GLP-1-Glu-PAL in an in vitro model of Parkinson’s disease
    Lin Li, Ke Liu, Juan Zhao, Christian Holscher, Guang-lai Li, Yue-ze Liu
    2016, 11 (2):  326-331.  doi: 10.4103/1673-5374.177742
    Abstract ( 324 )   PDF (1015KB) ( 414 )   Save

    The growth factor glucagon-like peptide-1 (GLP-1) is neuroprotective in several animal models of neurodegeneration. Here, we analyzed the neuroprotective effects of a novel protease-resistant GLP-1 analogue, (Val8)GLP-1-Glu-PAL, which has advantages over older analogues, such as improvement of hippocampal neurogenesis, glucose homeostasis, and insulin secretion. We established an in vitro model of Parkinson’s disease using the mitochondrial stressor rotenone in primary cultured mouse neurons pretreated with (Val8)GLP-1-Glu-PAL. (Val8)GLP-1-Glu-PAL alone did not affect neuronal viability, but prevented the rotenone-induced reduction in cell viability in a dose-dependent manner. In addition, (Val8)GLP-1-Glu-PAL pretreatment prevented rotenone-induced proapoptotic changes manifesting as downregulation of procaspase-3 and Bcl-2 and upregulation of cleaved caspase-3. These results demonstrate that the novel agent (Val8)GLP-1-Glu-PAL shows promise as a drug treatment for Parkinson’s disease.

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    Effects of microtubule-associated protein tau expression on neural stem cell migration after spinal cord injury
    Zhi-ping Qi, Guo-xiang Wang, Peng Xia, Ting-ting Hou, Hong-li Zhou, Tie-jun Wang, Xiao-yu Yang
    2016, 11 (2):  332-337.  doi: 10.4103/1673-5374.177744
    Abstract ( 258 )   PDF (2483KB) ( 532 )   Save

    Our preliminary proteomics analysis suggested that expression of microtubule-associated protein tau is elevated in the spinal cord after injury. Therefore, the first aim of the present study was to examine tau expression in the injured spinal cord. The second aim was to determine whether tau can regulate neural stem cell migration, a critical factor in the successful treatment of spinal cord injury. We established rat models of spinal cord injury and injected them with mouse hippocampal neural stem cells through the tail vein. We used immunohistochemistry to show that the expression of tau protein and the number of migrated neural stem cells were markedly increased in the injured spinal cord. Furthermore, using a Transwell assay, we showed that neural stem cell migration was not affected by an elevated tau concentration in the outer chamber, but it was decreased by changes in intracellular tau phosphorylation state. These results demonstrate that neural stem cells have targeted migration capability at the site of injury, and that although tau is not a chemokine for targeted migration of neural stem cells, intracellular tau phosphorylation/dephosphorylation can inhibit cell migration.

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    Influence of immobilization and sensory re-education on the sensory recovery after reconstruction of digital nerves with direct suture or muscle-in-vein conduits
    Theodora Manoli, Jennifer Lynn Schiefer, Lukas Schulz, Thomas Fuchsberger, Hans-Eberhard Schaller
    2016, 11 (2):  338-344.  doi: 10.4103/1673-5374.169638
    Abstract ( 276 )   PDF (623KB) ( 420 )   Save

    The influence of duration of immobilization and postoperative sensory re-education on the final outcome after reconstruction of digital nerves with direct suture or muscle-in-vein conduits was investigated. The final sensory outcome of 35 patients with 41 digital nerve injuries, who either underwent a direct suture (DS) or a nerve reconstruction with muscle-in-vein conduits (MVC), was assessed the earliest 12 months postoperatively using static and moving two-point discrimination as well as Semmes-Weinstein monofilaments.
    There was no significant difference in sensory recovery in cases with an immobilization of 3–7 days versus 10 days in the DS or MVC group. Moreover, no statistically significant difference in sensory recovery was found in cases receiving postoperative sensory re-education versus those not receiving in the DS or MVC group. An early mobilization does not seem to have a negative impact on the final outcome after digital
    nerve reconstruction. The effect of sensory re-education after digital nerve reconstruction should be reconsidered.

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    Epalrestat protects against diabetic peripheral neuropathy by alleviating oxidative stress and inhibiting polyol pathway
    Qing-rong Li, Zhuo Wang, Wei Zhou, Shou-rui Fan, Run Ma, Li Xue, Lu Yang, Ya-shan Li, Hong-li Tan, Qing-hua Shao,Hong-ying Yang
    2016, 11 (2):  345-351.  doi: 10.4103/1673-5374.177745
    Abstract ( 306 )   PDF (1963KB) ( 372 )   Save

    Epalrestat is a noncompetitive and reversible aldose reductase inhibitor used for the treatment of diabetic neuropathy. This study assumed that epalrestat had a protective effect on diabetic peripheral nerve injury by suppressing the expression of aldose reductase in peripheral nerves of diabetes mellitus rats. The high-fat and high-carbohydrate model rats were established by intraperitoneal injection of streptozotocin. Peripheral neuropathy occurred in these rats after sustaining high blood glucose for 8 weeks. At 12 weeks after streptozotocin injection, rats were intragastrically administered epalrestat 100 mg/kg daily for 6 weeks. Transmission electron microscope revealed that the injuries to myelinated nerve fibers, non-myelinated nerve fibers and Schwann cells of rat sciatic nerves had reduced compared to rats without epalrestat administuation. Western blot assay and immunohistochemical results demonstrated that after intervention with epalrestat, the activities of antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase gradually increased, but aldose reductase protein expression gradually diminished. Results confirmed that epalrestat could protect against diabetic peripheral neuropathy by relieving oxidative stress and suppressing the polyol pathway.

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