Publications by authors named "Saori Shimizu"

17 Publications

  • Page 1 of 1

Disruption of postnatal neurogenesis and adult-stage suppression of synaptic plasticity in the hippocampal dentate gyrus after developmental exposure to sterigmatocystin in rats.

Toxicol Lett 2021 Oct 11;349:69-83. Epub 2021 Jun 11.

Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan; Cooperative Division of Veterinary Sciences, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan; Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan. Electronic address:

Exposure to sterigmatocystin (STC) raises concerns on developmental neurological disorders. The present study investigated the effects of maternal oral STC exposure on postnatal hippocampal neurogenesis of offspring in rats. Dams were exposed to STC (1.7, 5.0, and 15.0 ppm in diet) from gestational day 6 until day 21 post-delivery (weaning), and offspring were maintained without STC exposure until adulthood on postnatal day (PND) 77, in accordance with OECD chemical testing guideline Test No. 426. On PND 21, 15.0-ppm STC decreased type-3 neural progenitor cell numbers in the subgranular zone (SGZ) due to suppressed proliferation. Increased γ-H2AX-immunoreactive () cell numbers in the SGZ and Ercc1 upregulation and Brip1 downregulation in the dentate gyrus suggested induction of DNA double-strand breaks in SGZ cells. Upregulation of Apex1 and Ogg1 and downregulation of antioxidant genes downstream of NRF2-Keap1 signaling suggested induction of oxidative DNA damage. Increased p21 SGZ cell numbers and suppressed cholinergic signaling through CHRNB2-containing receptors in GABAergic interneurons suggested potential neurogenesis suppression mechanisms. Multiple mechanisms involving N-methyl-d-aspartate (NMDA) receptor-mediated glutamatergic signaling and various GABAergic interneuron subpopulations, including CHRNA7-expressing somatostatin interneurons activated by BDNF-TrkB signaling, may be involved in ameliorating the neurogenesis. Upregulation of Arc, Ptgs2, and genes encoding NMDA receptors and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors suggested synaptic plasticity facilitation. On PND 77, ARC granule cells decreased, and Nos2 was upregulated following 15.0 ppm STC exposure, suggesting oxidative stress-mediated synaptic plasticity suppression. Inverse pattern in gene expression changes in vesicular glutamate transporter isoforms, Slc17a7 and Slc17a6, from weaning might also be responsible for the synaptic plasticity suppression. The no-observed-adverse-effect level of maternal oral STC exposure for offspring neurogenesis was determined to be 5.0 ppm, translating to 0.34-0.85 mg/kg body weight/day.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.toxlet.2021.06.006DOI Listing
October 2021

Gastrointestinal Hormone Cholecystokinin Increases P-Glycoprotein Membrane Localization and Transport Activity in Caco-2 Cells.

J Pharm Sci 2017 09 12;106(9):2650-2656. Epub 2017 Apr 12.

Laboratory of Clinical Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Takasaki University of Health and Welfare, 60 Nakaorui-machi, Takasaki, Gunma 370-0033, Japan.

It was reported that stimulation of taste receptor type 2 member 38 by a bitter substance, phenylthiocarbamide (PTC), increased P-glycoprotein (P-gp) mRNA level and transport activity via release of the gastrointestinal hormone cholecystokinin-8 (CCK-8) at 9 h. Therefore, we hypothesized that CCK-8 and PTC might also regulate P-gp activity more rapidly via a different mechanism. As a result, we found that the pretreatment of human colon adenocarcinoma (Caco-2) cells with 10-mM PTC significantly decreased the intracellular accumulation of P-gp substrate rhodamine 123 (Rho123) compared with the control after 90-min incubation. Moreover, CCK-8 treatments significantly reduced the accumulation of Rho123 within 30 min, compared with the control. On the other hand, when Caco-2 cells were pretreated with PTC, the efflux ratio of Rho123 was significantly increased compared with control. The efflux ratio of Rho123 in CCK-8 treatment cells was also significantly increased compared with control. Furthermore, CCK-8 increased the phosphorylation of the scaffold proteins ezrin, radixin, and moesin, which regulate translocation of P-gp to the plasma membrane. Therefore, our results indicate that PTC induced release of CCK-8, which in turn induced the phosphorylation of ezrin, radixin, and moesin proteins, leading to upregulation of P-gp transport activity via increased membrane localization of P-gp.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.xphs.2017.04.003DOI Listing
September 2017

Multispectral imaging and automated laser capture microdissection of human cortical neurons: a quantitative study of CXCR4 expression.

Methods Mol Biol 2013 ;1013:31-48

Department of Pharmacology, Drexel University College of Medicine, Philadelphia, PA, USA.

Quantifying protein and RNA expression within specific cell populations in vivo is an essential step in unraveling the complex mechanisms of neurological disease. The challenges associated with studying human brain tissue are commonly compounded by variations in postmortem interval, formalin fixation time, and tissue processing methods among others. The result is a sample population that is inherently heterogeneous, implying the need for reliable protocols that are sensitive to low levels of antigen while minimizing background and nonspecific staining. Here, we describe a single immunohistochemistry protocol on formalin-fixed, paraffin-embedded human cortex which can be adapted to (1) quantify the relative protein expression of the chemokine receptor, CXCR4, using multispectral image or (2) isolate neuronal RNA through automated laser capture microdissection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-62703-426-5_3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4011070PMC
November 2013

Bilaminar co-culture of primary rat cortical neurons and glia.

J Vis Exp 2011 Nov 12(57). Epub 2011 Nov 12.

Department of Pharmacology and Physiology, Drexel University College of Medicine.

This video will guide you through the process of culturing rat cortical neurons in the presence of a glial feeder layer, a system known as a bilaminar or co-culture model. This system is suitable for a variety of experimental needs requiring either a glass or plastic growth substrate and can also be used for culture of other types of neurons. Rat cortical neurons obtained from the late embryonic stage (E17) are plated on glass coverslips or tissue culture dishes facing a feeder layer of glia grown on dishes or plastic coverslips (known as Thermanox), respectively. The choice between the two configurations depends on the specific experimental technique used, which may require, or not, that neurons are grown on glass (e.g. calcium imaging versus Western blot). The glial feeder layer, an astroglia-enriched secondary culture of mixed glia, is separately prepared from the cortices of newborn rat pups (P2-4) prior to the neuronal dissection. A major advantage of this culture system as compared to a culture of neurons only is the support of neuronal growth, survival, and differentiation provided by trophic factors secreted from the glial feeder layer, which more accurately resembles the brain environment in vivo. Furthermore, the co-culture can be used to study neuronal-glial interactions(1). At the same time, glia contamination in the neuronal layer is prevented by different means (low density culture, addition of mitotic inhibitors, lack of serum and use of optimized culture medium) leading to a virtually pure neuronal layer, comparable to other established methods(1-3). Neurons can be easily separated from the glial layer at any time during culture and used for different experimental applications ranging from electrophysiology(4), cellular and molecular biology(5-8), biochemistry(5), imaging and microscopy(4,6,7,9,10). The primary neurons extend axons and dendrites to form functional synapses(11), a process which is not observed in neuronal cell lines, although some cell lines do extend processes. A detailed protocol of culturing rat hippocampal neurons using this co-culture system has been described previously(4,12,13). Here we detail a modified protocol suited for cortical neurons. As approximately 20x10(6) cells are recovered from each rat embryo, this method is particularly useful for experiments requiring large numbers of neurons (but not concerned about a highly homogenous neuronal population). The preparation of neurons and glia needs to be planned in a time-specific manner. We will provide the step-by-step protocol for culturing rat cortical neurons as well as culturing glial cells to support the neurons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/3257DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308589PMC
November 2011

Color standardization method and system for whole slide imaging based on spectral sensing.

Anal Cell Pathol (Amst) 2012 ;35(2):107-15

Olympus Corporation, Imaging Technology Department, Hachioji-shi, Tokyo, Japan. shinsuke

In the field of whole slide imaging, the imaging device or staining process cause color variations for each slide that affect the result of image analysis made by pathologist. In order to stabilize the analysis, we developed a color standardization method and system as described below. (1) Color standardization method based on RGB imaging and multi spectral sensing, which utilize less band (16 bands) than conventional method (60 bands). (2) High speed spectral sensing module. As a result, we confirmed the following effect. (1) We confirmed the performance improvement of nucleus detection by the color standardization. And we can conduct without training data set which is needed in conventional method. (2) We can get detection performance of H&E component equivalent to conventional method (60 bands). And measurement process is more than 255 times faster.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3233/ACP-2011-0037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605804PMC
May 2012

CXCR7 protein expression in human adult brain and differentiated neurons.

PLoS One 2011 31;6(5):e20680. Epub 2011 May 31.

Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America.

Background: CXCR7 and CXCR4 are receptors for the chemokine CXCL12, which is involved in essential functions of the immune and nervous systems. Although CXCR7 transcripts are widely expressed throughout the central nervous system, little is known about its protein distribution and function in the adult brain. To evaluate its potential involvement in CXCL12/CXCR4 signaling in differentiated neurons, we studied CXCR7 protein expression in human brain and cultured neurons.

Methodology/principal Findings: Immunohistochemistry and RT-PCR analyses of cortex and hippocampus from control and HIV-positive subjects provided the first evidence of CXCR7 protein expression in human adult neurons, under normal and pathological conditions. Furthermore, confocal microscopy and binding assays in cultured neurons show that CXCR7 protein is mainly located into cytoplasm, while little to no protein expression is found on neuronal plasma membrane. Interestingly, specific CXCR7 ligands that inhibit CXCL12 binding to CXCR7 do not alter CXCR4-activated survival signaling (pERK/pAkt) in rat cortical neurons. Neuronal CXCR7 co-localizes to some extent with the endoplasmic reticulum marker ERp29, but not with early/late endosome markers. Additionally, large areas of overlap are detected in the intracellular pattern of CXCR7 and CXCR4 expression.

Conclusions/significance: Overall, these results implicate CXCR4 as the main CXCL12 signaling receptor on the surface of differentiated neurons and suggest that CXCR7 may interact with CXCR4 at the intracellular level, possibly affecting CXCR4 trafficking and/or coupling to other proteins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020680PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3105114PMC
October 2011

Disruption of neuronal CXCR4 function by opioids: preliminary evidence of ferritin heavy chain as a potential etiological agent in neuroAIDS.

J Neuroimmunol 2010 Jul 8;224(1-2):66-71. Epub 2010 Jun 8.

Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th Street, Philadelphia, PA 19102, USA.

The chemokine CXCL12 and its receptor, CXCR4, regulate neuronal migration, differentiation, and survival. Alterations of CXCL12/CXCR4 signaling are implicated in different neuropathologies, including the neurological complications of HIV infection. Opiates are important co-factors for progression to neuroAIDS and can disrupt the CXCL12/CXCR4 axis in vitro and in vivo. This paper will review recently identified mechanisms of opiate-induced CXCR4 impairment in neurons and introduce results from pilot studies in human brain tissue, which highlight the role of the protein ferritin heavy chain in HIV neuropathology in patients with history of drug abuse.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jneuroim.2010.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910242PMC
July 2010

Interactions between chemokines: regulation of fractalkine/CX3CL1 homeostasis by SDF/CXCL12 in cortical neurons.

J Biol Chem 2010 Apr 2;285(14):10563-71. Epub 2010 Feb 2.

Departments of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.

The soluble form of the chemokine fractalkine/CX(3)CL1 regulates microglia activation in the central nervous system (CNS), ultimately affecting neuronal survival. This study aims to determine whether CXCL12, another chemokine constitutively expressed in the CNS (known as stromal cell-derived factor 1; SDF-1), regulates cleavage of fractalkine from neurons. To this end, ELISA was used to measure protein levels of soluble fractalkine in the medium of rat neuronal cultures exposed to SDF-1. Gene arrays, quantitative RT-PCR, and Western blot were used to measure overall fractalkine expression in neurons. The data show that the rate of fractalkine shedding in healthy cultures positively correlates with in vitro differentiation and survival. In analogy to non-neuronal cells, metalloproteinases (ADAM10/17) are involved in cleavage of neuronal fractalkine as indicated by studies with pharmacologic inhibitors. Moreover, treatment of the neuronal cultures with SDF-1 stimulates expression of the inducible metalloproteinase ADAM17 and increases soluble fractalkine content in culture medium. The effect of SDF-1 is blocked by an inhibitor of both ADAM10 and -17, but only partially affected by a more specific inhibitor of ADAM10. In addition, SDF-1 also up-regulates expression of the fractalkine gene. Conversely, exposure of neurons to an excitotoxic stimulus (i.e. NMDA) inhibits alpha-secretase activity and markedly diminishes soluble fractalkine levels, leading to cell death. These results, along with previous findings on the neuroprotective role of both SDF-1 and fractalkine, suggest that this novel interaction between the two chemokines may contribute to in vivo regulation of neuronal survival by modulating microglial neurotoxic properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M109.035477DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2856264PMC
April 2010

Morphine increases brain levels of ferritin heavy chain leading to inhibition of CXCR4-mediated survival signaling in neurons.

J Neurosci 2009 Feb;29(8):2534-44

Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA.

This study focuses on the effect of mu-opioid receptor agonists on CXCR4 signaling in neurons and the mechanisms involved in regulation of neuronal CXCR4 by opiates. The data show that CXCR4 is negatively modulated by long-term morphine treatments both in vitro and in vivo; CXCR4 inhibition is caused by direct stimulation of mu-opioid receptors in neurons, leading to alterations of ligand-induced CXCR4 phosphorylation and upregulation of protein ferritin heavy chain (FHC), a negative intracellular regulator of CXCR4. Reduced coupling of CXCR4 to G-proteins was found in the brain of morphine-treated rats, primarily cortex and hippocampus. CXCR4-induced G alpha(i)/G betagamma activities were suppressed after 24 h treatment of cortical neurons with morphine or the selective mu-opioid agonist DAMGO (D-Ala2-N-Me-Phe(4)-glycol(5)-enkephalin), as shown by analysis of downstream targets of CXCR4 (i.e., cAMP, Akt, and ERK1/2). These agonists also prevented CXCL12-induced phosphorylation of CXCR4, indicating a deficit of CXCR4 activation in these conditions. Indeed, morphine (or DAMGO) inhibited prosurvival signaling in neurons. These effects are not attributable to a reduction in CXCR4 expression or surface levels but rather to upregulation of FHC by opioids. The crucial role of FHC in inhibition of neuronal CXCR4 was confirmed by in vitro and in vivo RNA interference studies. Overall, these findings suggest that opiates interfere with normal CXCR4 function in the brain. By this mechanism, opiates could reduce the neuroprotective functions of CXCR4 and exacerbate neuropathology in opiate abusers who are affected by neuroinflammatory/infectious disorders, including neuroAIDS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.5865-08.2009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664553PMC
February 2009

CX3CR1 is expressed by prostate epithelial cells and androgens regulate the levels of CX3CL1/fractalkine in the bone marrow: potential role in prostate cancer bone tropism.

Cancer Res 2008 Mar;68(6):1715-22

Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.

We have previously shown that the chemokine fractalkine promotes the adhesion of human prostate cancer cells to bone marrow endothelial cells as well as their migration toward human osteoblasts in vitro. Thus, the interaction of fractalkine with its receptor CX3CR1 could play a crucial role in vivo by directing circulating prostate cancer cells to the bone. We found that although CX3CR1 is minimally detectable in epithelial cells of normal prostate glands, it is overexpressed upon malignant transformation. Interestingly, osteoblasts, stromal and mesenchymal cells derived from human bone marrow aspirates express the cell-bound form of fractalkine, whereas the soluble form of the chemokine is detected in bone marrow supernatants. To investigate the mechanisms regulating the levels of soluble fractalkine in the bone marrow, we focused on androgens, which play a critical role in both prostate cancer progression and skeletal metastasis. Here, we show that dihydrotestosterone dramatically increases the cleavage of fractalkine from the plasma membrane of bone cells and its action is reversed by nilutamide--an antagonist of the androgen receptor--as well as the wide-spectrum inhibitor of matrix metalloproteases, GM6001. However, dihydrotestosterone was unable to induce fractalkine-cleavage from human bone marrow endothelial cells. Thus, androgens could promote the extravasation of CX3CR1-bearing cancer cells on a fractalkine concentration gradient, while leaving unaltered their ability to adhere to the bone marrow endothelium. In conclusion, our results indicate that CX3CR1, fractalkine, and the enzymes responsible for its cleavage might represent suitable targets for therapies aiming to counteract skeletal secondary tumors from prostate adenocarcinoma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-07-1315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669735PMC
March 2008

Modulation of dendritic cell maturation and function by the Tax protein of human T cell leukemia virus type 1.

J Leukoc Biol 2007 Jul 18;82(1):44-56. Epub 2007 Apr 18.

Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA.

Human T cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by the generation of an intense CTL cell response directed against the viral transactivator protein Tax. In addition, patients diagnosed with HAM/TSP exhibit rapid activation and maturation of dendritic cells (DC), likely contributing to the robust, Tax-specific CTL response. In this study, extracellular Tax has been shown to induce maturation and functional alterations in human monocyte-derived DC, critical observations being confirmed in freshly isolated myeloid DC. Tax was shown to promote the production of proinflammatory cytokines and chemokines involved in the DC activation process in a dose- and time-dependent manner. Furthermore, Tax induced the expression of DC activation (CD40, CD80, and CD86) and maturation (CD83) markers and enhanced the T cell proliferation capability of DC. Heat inactivation of Tax resulted in abrogation of these effects, indicating a requirement for the native structure of Tax, which was found to bind efficiently to the DC membrane and was internalized within a few hours, suggesting that extracellular Tax may possess an intracellular mechanism of action subsequent to entry. Finally, inhibitors of cellular signaling pathways, NF-kappaB, protein kinase, tyrosine kinase, and phospholipase C, were shown to inhibit Tax-mediated DC activation. This is the first study reporting the immunomodulatory effects of extracellular Tax in the DC compartment. These results suggest that DC, once exposed to Tax by uptake from the extracellular environment, can undergo activation, providing constant antigen presentation and costimulation to T cells, leading to the intense T cell proliferation and inflammatory responses underlying HAM/TSP.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1189/jlb.1006641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2712352PMC
July 2007

Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology.

Neurobiol Dis 2007 Jan 28;25(1):17-26. Epub 2006 Sep 28.

Department of Pharmacology and Physiology, Drexel University, College of Medicine, 245 North 15th Street, NCB 8804, Philadelphia, PA 19102, USA.

This study sought to determine the role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology. We studied the effect of the HIV envelope protein gp120 on the expression of E2F1-dependent apoptotic proteins in human and rodent neurons and examined the expression pattern of E2F1 in the brain of HIV-infected individuals. Our findings suggest that in cultured neurons gp120 increased E2F1 levels in the nucleus, stimulated its transcriptional activity and enhanced the expression of the E2F1 target proteins Cdc2 and Puma. Studies with neuronal cultures from E2F1 deficient mice demonstrated that the transcription factor is required for gp120-induced neurotoxicity and up-regulation of Cdc2 and Puma. Levels of E2F1 protein were greater in the nucleus of neurons in brains of HIV-infected patients exhibiting dementia when compared to HIV-negative subjects or HIV-positive neurologically normal patients. Overall, these studies indicate that E2F1 is primarily involved in CXCR4-mediated neurotoxicity and HIV neuropathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nbd.2006.08.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1762194PMC
January 2007

Neural progenitor cells engineered to secrete GDNF show enhanced survival, neuronal differentiation and improve cognitive function following traumatic brain injury.

Eur J Neurosci 2006 Apr;23(8):2119-34

Traumatic Brain Injury Laboratory, Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA.

We sought to evaluate the potential of C17.2 neural progenitor cells (NPCs) engineered to secrete glial cell line-derived neurotrophic factor (GDNF) to survive, differentiate and promote functional recovery following engraftment into the brains of adult male Sprague-Dawley rats subjected to lateral fluid percussion brain injury. First, we demonstrated continued cortical expression of GDNF receptor components (GFRalpha-1, c-Ret), suggesting that GDNF could have a physiological effect in the immediate post-traumatic period. Second, we demonstrated that GDNF over-expression reduced apoptotic NPC death in vitro. Finally, we demonstrated that GDNF over-expression improved survival, promoted neuronal differentiation of GDNF-NPCs at 6 weeks, as compared with untransduced (MT) C17.2 cells, following transplantation into the perilesional cortex of rats at 24 h post-injury, and that brain-injured animals receiving GDNF-C17.2 transplants showed improved learning compared with those receiving vehicle or MT-C17.2 cells. Our results suggest that transplantation of GDNF-expressing NPCs in the acute post-traumatic period promotes graft survival, migration, neuronal differentiation and improves cognitive outcome following traumatic brain injury.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1460-9568.2006.04743.xDOI Listing
April 2006

Selective temporal and regional alterations of Nogo-A and small proline-rich repeat protein 1A (SPRR1A) but not Nogo-66 receptor (NgR) occur following traumatic brain injury in the rat.

Exp Neurol 2006 Jan;197(1):70-83

Traumatic Brain Injury Laboratory, Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.

Axons show a poor regenerative capacity following traumatic central nervous system (CNS) injury, partly due to the expression of inhibitors of axonal outgrowth, of which Nogo-A is considered the most important. We evaluated the acute expression of Nogo-A, the Nogo-66 receptor (NgR) and the novel small proline-rich repeat protein 1A (SPRR1A, previously undetected in brain), following experimental lateral fluid percussion (FP) brain injury in rats. Immunofluorescence with antibodies against Nogo-A, NgR and SPRR1A was combined with antibodies against the neuronal markers NeuN and microtubule-associated protein (MAP)-2 and the oligodendrocyte marker RIP, while Western blot analysis was performed for Nogo-A and NgR. Brain injury produced a significant increase in Nogo-A expression in injured cortex, ipsilateral external capsule and reticular thalamus from days 1-7 post-injury (P < 0.05) compared to controls. Increased expression of Nogo-A was observed in both RIP- and NeuN positive (+) cells in the ipsilateral cortex, in NeuN (+) cells in the CA3 region of the hippocampus and reticular thalamus and in RIP (+) cells in white matter tracts. Alterations in NgR expression were not observed following traumatic brain injury (TBI). Brain injury increased the extent of SPRR1A expression in the ipsilateral cortex and the CA3 at all post-injury time-points in NeuN (+) cells. The marked increases in Nogo-A and SPRR1A in several important brain regions suggest that although inhibitors of axonal growth may be upregulated, the injured brain is also capable of expressing proteins promoting axonal outgrowth following TBI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.expneurol.2005.08.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2849132PMC
January 2006

Regulation of neuronal P53 activity by CXCR 4.

Mol Cell Neurosci 2005 Sep;30(1):58-66

Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th Street, NCB 8804, Philadelphia, PA 19102, USA.

Abnormal activation of CXCR 4 during inflammatory/infectious states may lead to neuronal dysfunction or damage. The major goal of this study was to determine the coupling of CXCR 4 to p53-dependent survival pathways in primary neurons. Neurons were stimulated with the HIV envelope protein gp120(IIIB) or the endogenous CXCR 4 agonist, SDF-1 alpha. We found that gp120 stimulates p53 activity and induces expression of the p53 pro-apoptotic target Apaf-1 in cultured neurons. Inhibition of CXCR 4 by AMD 3100 abrogates the effect of gp120 on both p53 and Apaf-1. Moreover, gp120 neurotoxicity is markedly reduced by the p53-inhibitor, pifithrin-alpha. The viral protein also regulates p53 phosphorylation and expression of other p53-responsive genes, such as MDM 2 and p21. Conversely, SDF-1 alpha, which can promote neuronal survival, increases p53 acetylation and p21 expression in neurons. Thus, the stimulation of different p53 targets could be instrumental in determining the outcome of CXCR 4 activation on neuronal survival in neuro-inflammatory disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcn.2005.05.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2665035PMC
September 2005

Lifecorder: a new device for the long-term monitoring of motor activities for Parkinson's disease.

Intern Med 2004 Aug;43(8):685-92

Department of Neurology, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295.

Objective: To quantitatively evaluate motor activity, its fluctuations, and drug effects in patients with Parkinson's disease (PD), the Lifecorder, a new monitoring device, was attached to a group of patients for several weeks. This enabled the continuous recording of motor activity in ten scaled magnitudes at two-minute intervals for 6 weeks.

Patients And Methods: Thirteen patients with PD who required dopamine receptor agonist therapy were monitored with Lifecorder, and seven healthy subjects served as the control group. The data obtained with this device correlated well with the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn-Yahr grading. The dose of cabergoline, a D2-receptor agonist, was increased every 2 weeks, until optimum improvement was achieved.

Results: By adding cabergoline, the mean UPDRS improved from 40.5 to 28.4, which was significant. In parallel, the mean daily walking count (WC) also increased from 2,459 to 3,315 steps (p < 0.01) and movement-related calorie consumption (MCC) increased from 56 to 74 kcal (p < 0.05). UPDRS thus correlated well with WC and MCC (p < 0.05) obtained with this device. The improvement ratio of WC and MCC of each individual patient was compared with that of UPDRS. WC, and MCC shifted in parallel with UPDRS with one exception. The daily time-dependent fluctuation of motor activity was clearly shown by the Excel-generated graphs to improve with D-agonist therapy. In contrast to enhanced daytime activities, nocturnal restfulness was also clearly documented with this device.

Conclusion: The unique properties of Lifecorder make this device a useful adjunct to the UPDRS for the objective evaluation of Parkinsonian motor activity. The device has a significant advantage over conventional clinical scales, as daytime as well as nocturnal motor activity can be objectively evaluated over long time periods ranging from one hour to one month, and the magnitude of motor activity is quantifiable in relation to the time-course.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2169/internalmedicine.43.685DOI Listing
August 2004

From cell death to neuronal regeneration: building a new brain after traumatic brain injury.

J Neuropathol Exp Neurol 2003 Aug;62(8):801-11

Head Injury Center, Department of Neurosurgery University of Pennsylvania, Philadelphia, Pennsylvania, USA.

During the past decade, there has been accumulating evidence of the involvement of passive and active cell death mechanisms in both the clinical setting and in experimental models of traumatic brain injury (TBI). Traditionally, research for a treatment of TBI consists of strategies to prevent cell death using acute pharmacological therapy. However, to date, encouraging experimental work has not been translated into successful clinical trials. The development of cell replacement therapies may offer an alternative or a complementary strategy for the treatment of TBI. Recent experimental studies have identified a variety of candidate cell lines for transplantation into the injured CNS. Additionally, the characterization of the neurogenic potential of specific regions of the adult mammalian brain and the elucidation of the molecular controls underlying regeneration may allow for the development of neuronal replacement therapies that do not require transplantation of exogenous cells. These novel strategies may represent a new opportunity of great interest for delayed intervention in patients with TBI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jnen/62.8.801DOI Listing
August 2003
-->