Day 2 :
Keynote Forum
Gjumrakch Aliev
President, GALLY International Biomedical Research Institute Inc. USA.
Keynote: The oxidative stress initiated mitochondrial DNA overproliferation and deletion in the context of the Cancer and Neurodegeneration: Recent Challenge in Neuropharmacology
Time : 09:00-09:25
Biography:
Dr. Gjumrakch Aliev, MD, PhD, President “GALLY” International Biomedical Research Institute Inc., San Antonio, Texas, USA. He also hold appointment with the University of Atlanta, Atlanta, Georgia, USA as a Professor of Cardiovascular, Neuropathology, Gerontology, Health Science and Healthcare Administration. He authored and coauthored more than 500 publications in the fields of neurodegenerative diseases research (Alzheimer disease), as well as cardio- and cerebrovascular disease, cancer, and electron microscopy. He is nationally and internationally reputed in his area. Dr. Aliev’s accomplishments in the area of biochemistry and cellular biology have tremendous implications for drug design towards CNS Neurological Disorders, AD, cancer, and cerebrovascular and neurodegeneration related pathologies. He is world-renowned expert in electron microscopy. His work has been published in numerous prestigious journals such as Nature Clinical Cardiology, J. Neuroscience, Circulation Research, New England journal of Medicine, Blood, J. Cellular and Molecular Medicine, Atherosclerosis, CNS Neurological Disorders & Drug Targets, International J. Biochemistry and Cell Biology, and many others which reflect his leading role in his research areas. He is currently the Editor in Chiefs for “Central Nervous System Agents in Medicinal Chemistry”, “Applied Cell Biology”, “World Journal of Neuroscience”, “Open Journal of Psychiatry” and “Journal of Aging Science”, Cardiovascular & Hematological Agents in Medicinal Chemistry as well as which by itself shows the voluminous and outstanding work he has accomplished in the area of cellular and molecular biology as well as aged associated clinical sciences. He is one of most cited authors in his fields with high impact factors.
Abstract:
It has been postulated that Alzheimer disease (AD) and cancer are systemic process, which involves multiple pathophysiological factors. Nitric oxide- (NO-) dependent oxidative stress appeared to be key pathway that results in mitochondrial ultrastructural alterations and DNA damage in cases of Alzheimer disease (AD) and may be in other pathology. However, little is known about these pathways in human cancers, especially during the development as well as the progression of primary brain tumors and metastatic colorectal cancer. One of the key features of tumors is the deficiency in tissue energy that accompanies mitochondrial lesions and formation of the hypoxic smaller sized mitochondria with ultrastructural abnormalities. We theorize that mitochondrial involvement may play a significant role in the etiopathogenesis of cancer. Recent studies also demonstrate a potential link between AD and cancer, and anticancer drugs are being explored for the inhibition of AD-like pathology in transgenic mice. Severity of the cancer growth, metastasis, and brain pathology in AD (in animal models that mimic human AD) correlate with the degree of mitochondrial ultrastructural abnormalities. Recent advances in the cell-cycle reentry of the terminally differentiated neuronal cells indicate that NO-dependent mitochondrial abnormal activities and mitotic cell division are not the only important pathogenic factors in pathogenesis of cancer and AD, but open a new window for the development of novel more specific and target based treatment strategies at least for these devastating diseases.
Keynote Forum
Nachum Dafny
The University of Texas Health Science Center at Houston, USA
Keynote: Does Ritalin have the potential to become a drug of abuse?
Time : 09:25-10:05
Biography:
The prefrontal cortex (PFC) is involved in complex planning, learning, memory, attention and integrates sensory information. It was reported that the PFC is dysfunctional in attention deficit hyperactivity disorder (ADHD). Methylphenidate (MPD), a drug often prescribed for the treatment of ADHD, has potential for abuse and misuse. Most MPD studies were completed in adult subjects; however most users are adolescents. The objective of this study was to investigate the acute and chronic dose response characteristics of MPD on PFC neuronal activity recorded in freely behaving adolescent rats. Four groups of animals were used: saline (control), 0.6, 2.5, and 10 mg/kg MPD. Acute MPD elicited a dose response increase in animals’ locomotor activity. Rechallenge with MPD at experimental day (ED10) when compared to the effect of MPD at ED1 showed no significant differences. When the animals were divided into two groups based on their individual responses to chronic MPD exposure, some animals expressed behavioral tolerance and some expressed behavioral sensitization. Electrophysiologically, a dose response characteristic for acute and chronic MPD exposure was observed. With increasing MPD doses, more PFC units responded by changing their firing rate. Moreover, the neuronal responses to chronic MPD recorded from animals expressing behavioral tolerance were significantly different compared to the neuronal population responses recorded from animals expressing behavioral sensitization. The majority of the PFC units recorded from animals expressing behavioral tolerance responded to MPD predominately by decreasing their firing rates, whereas PFC units recorded from behaviorally sensitized animals mainly showed an increase in their firing rates.
Abstract:
Nachum Dafny received his MS and PhD degrees from Hadassah Medical School in Jerusalem in 1965 and 1969, respectively followed by post-docs at Caltech, UCLA, and Columbia. He is currently a Professor of Neurobiology at the University of Texas Medical School at Houston.
- Symposoium on Ca2+-interlocked membrane guanylate cyclase transduction network: Biochemistry and Physiology
Location: Hilton San Antonio Airport
Session Introduction
Rameshwar K Sharma
Salus University, USA
Title: Membrane guanylate cyclase: A multimodal cell signaling switch
Time : 10:05-10:25
Biography:
After his undergraduate work in the Birla Institute Pilani, India, Dr. Sharma received his Ph.D. from the University of Connecticut. His research is dedicated to the advancement of the field of membrane guanylate cyclases (MGCs). Discovery of the first membrane guanylate cyclase, ANF-RGC, established cyclic GMP as an intracellular hormonal second messenger. Discovery of others demonstrated that the operational principles of the MGCs transduction mechanisms are complex and unique to each form. Contrary to the other two signaling systems, cyclic AMP and IP3, cyclic GMP pathway dispenses with intermediaries. The hormone binds to an MGC and catalyzes its activity directly. The pathway is multifaceted, its molecular design incorporates multiple regulations: by ATP, Ca2+-sensing subunits and atmospheric carbon dioxide. These diverse effectors confer MGC cellular specificity and multi-switching signaling attributes linked with the physiology of cardiac vasculature, smooth muscle relaxation, blood pressure regulation, cellular growth, sensory transductions, neural plasticity and memory.
Abstract:
This presentation covers the latest state-of-the art developments on the biochemistry and physiology of the Membrane Guanylate Cyclase (MGC) field at the basic molecular, technological and clinical levels. (1) The membrane guanylate cyclase transduction system differs from the three-component design of its predecessor cyclic AMP second messenger system: adenylate cyclase, G-protein and G-protein coupled receptors, in that it consists of a single entity, a membrane-spanning protein that serves as both receptor and signal transducer. Notably, it also differs structurally from its soluble form, which is hetero-dimeric and requires heme for its activity. (2) Upon purification and characterization of the first MGC, several major surprises emerged. The MGC is also a surface receptor of the polypeptide hormone, Atrial Natriuretic Factor (ANF). This feature changes the paradigms of the modes of formation and function of the second messenger in cell signaling. Because ANF is the most hypotensive hormone, it paves new ways to understand its mechanism of action at the most basic level and to develop drugs against irregularities of the cardiac vasculature. Application of the mouse genetics exposes a remarkable 7-amino acid residue encoded motif of ANF-RGC that controls all ANF-modulated blood pressure regulated activity. Furthermore, the ANF-RGC discovery creates the impression that the hormonal signal transduction is its exclusive physiological function. (3) The impression crumbles with the discovery of ROS-GC MGC. ROS-GC expands the family; links it with the physiology of photo-transduction; and transcends a strictly neural function. The ROS-GC subfamily represents a new template of MGC signal transduction system. The novel feature is that in a feedback mechanism it interlocks with the light-induced fall in [Ca2+]i occurring in the outer segments of the rods and cones. (4) In contrast to the ANF-RGC, the ROS-GC is two-component transduction machinery. It employs its sensor components, GCAPs and S100B (a CD-GCAP), to capture [Ca2+]I signals and utilizes ROS-GC as a transducer component. (5) Accordingly, the first ROS-GC-modulated photo-transduction molecular model is proposed. It plays a pivotal role in the discovery and therapeutically diagnosed analysis of the ROS-GC gene-linked dystrophies. (6) An extraordinary feature specific for cone photo-transduction is uncovered where the ROS-GC is a bimodal Ca2+ transduction switch. It turns “OFF” as intracellular [Ca2+] rises above 75 nM, but then turns back “ON” when [Ca2+] exceeds 345 nM. The “OFF” mode is controlled by GCAPs and the “ON” mode by S100B. These modes occur uniquely in the outer segments and their occurrence in synapses of the cones in rodent retinas extends the role of ROS-GC beyond photo-transduction to the signaling processes between the photoreceptor and cone ON-bipolar cells. (7) The finding that another Ca2+-sensor CD-GCAP, Neurocalcin ï¤ (NCï¤), is expressed in the Inner Plexiform Layer (IPL) of the retina establishes linkage with signaling by additional neurons. (8) The presence of ROS-GC transduction system in the olfactory bulb and of a variant form of ROS-GC, ONE-GC, in the “necklace ONE-GC” neurons links it with the odorant transduction. Here, four amazing features of the Ca2+-modulated ONE-GC transduction system are disclosed. (i) In addition to ROS-GC1, GCAP1 is also a Ca2+-sensor component of ONE-GC. (ii) Yet, in contrast to the ROS-GC, it modulates ONE-GC catalytic activity only in the higher range of Ca2+, K1/2 of 700 nM. (iii) Instead of inhibiting, it stimulates the guanylate cyclase activity. (iv) The ONE-GC captures odorant signals at its extracellular domain and amplifies them at multiple intracellular domains, incorporating features of both ANF-RGC and ROS-GC transduction systems. (9) The presence of GCAP1- and S100B-modulated ROS-GC1 transduction systems in pinealocytes and of the Ca2+-sensor frequenin-modulated ROS-GC-like in hippocampal layers links the Ca2+-modulated MGC transduction system with “Other than Vision-Linked” Neurons. (10) In a total paradigm change, the dogma is shattered that ANF-RGC, is the specific transducer of ANF alone. It is now known that ANF-RGC also transduces a Ca2+ signal. Ca2+ captured by its sensor NCδ directly activates the catalytic module of ANF-RGC. Accordingly, and impressively, targeted gene-deletion mouse model studies demonstrate that both pathways are linked with blood pressure regulation. Their disruption causes hypertension. Thus the ANF-RGC embodies the combined features of hormone receptor and ROS-GC forms of membrane guanylate cyclases. These studies also broaden classification of the Ca2+ sensors. NCδ, originally classified as a neuronal calcium sensor, serves more widespread functions. (11) With the discovery that the Ca2+-bimodal modulated ROS-GC1 transduction switch occurs in the male gonads, the MGC network extends to the fertility field. Finally, (12) in an extraordinary development photoreceptor ROS-GC via a Ca2+-independent mechanism interlinks its CO2 and the Ca2+-modulated signaling modes. Yet, the Ca2+-modulated modes remain segregated. The domain targeted by CO2 is conserved in the family, thus regulation by CO2 may turn out to be a universal property of the membrane guanylate cyclase family.
Clint L. Makino
Boston University, USA
Title: Synergistic Modulation of the Membrane Guanylate Cyclases in Retinal Rods and Cones by Bicarbonate and Calcium
Time : 10:25-10:45
Biography:
Clint Makino completed his PhD at Florida State University and postdoctoral studies at Stanford University School of Medicine. He is currently an Associate Professor of Physiology and Biophysics at Boston University School of Medicine. He has published more than 50 journal papers and book chapters and serves on the editorial board of Frontiers in Molecular Neuroscience.
Abstract:
In the first step of vision, retinal rods and cones capture light and generate an electrical response. Upon photoexcitation, the visual pigment activates a G protein coupled cascade that results in hydrolysis of the ROS-GC guanylate cyclase-generated cGMP, closure of cyclic nucleotide gated (CNG) cation channels and membrane hyperpolarization. To control the growth of the response and to speed up the recovery, there is a negative feedback loop based on free [Ca2+]. In darkness, Ca2+ enters the photoreceptor through the CNG channel. Channel closure by induced by light prevents Ca2+ entry, but continued extrusion by an exchanger causes the intracellular [Ca2+] to fall. Guanylate cyclase activating proteins (GCAPs) sense the fall and stimulate the ROS-GC catalytic activity to regenerate cGMP. As cGMP returns to the resting levels present in darkness, CNG channels re-open, Ca2+ enters and cGMP synthesis slows to its basal rate. In the presented pardigm, bicarbonate stimulates the membrane guanylate cyclase independently of Ca2+. But in the presence of GCAPs and low Ca2+, the impact of bicarbonate is greater than the sum of each factor in isolation. This synergism between bicarbonate and GCAPs at low Ca2+ has the physiological effect of boosting the maximal response amplitude, quickening photon response recovery and reducing sensitivity to flashes and to steady light.
Teresa Duda
Salus University, USA
Title: Ca2+ sensor S100B in cone phototransduction
Time : 11:00-11:20
Biography:
Teresa Duda received her PhD from A. Mickiewicz University Poznan, Poland. In 1987 she joined Dr. Sharma’s research group at the University of Tennessee, Memphis as a post-doctoral fellow and started her work on membrane guanylate cyclase signal transduction. She is now professor at Salus University in Elkins Park, PA and continues to study various aspects of membrane guanylate cyclase signaling. She has published more than 90 papers in high-input journals and has been serving as an editorial board member of Frontiers in Molecular Neuroscience.
Abstract:
As the eye flicks about a scene, a photoreceptor, rod and cone, sees an alternating pattern of light and dark. This pattern is transduced by the photoreceptor outer segment into electrical signals (a mechanism termed phototransduction), and these signals are processed first by the retina, then by the visual cortex, and finally are decoded as the perceived image. In the phototransduction cascade of rods and cones, the second messenger cyclic GMP is generated by membrane-bound guanylate cyclases (ROS-GCs). In darkness, cyclic GMP opens cyclic nucleotide-gated (CNG) channels and a steady influx of Na+ and Ca2+ enters the outer segment and keeps the photoreceptor depolarized. Photons trigger hydrolysis of cyclic GMP, closing the channels and hyperpolarizing the photoreceptor. The recovery phase occurs when the Na+/Ca2+,K+ exchanger reduces intracellular concentration of Ca2+. Guanylate cyclase-activating proteins (GCAPs) sense this fall and stimulate ROS-GCs to synthesize cyclic GMP at a faster rate, leading to recovery of the photoreceptor dark current. The basic phototransduction components of rods and cones are similar, but important differences render rods more sensitive and cones faster with a larger dynamic range. While rods express ROS-GC1, ROS-GC2, GCAP1, and GCAP2, cones express only ROS-GC1 and GCAP1. We have discovered that cone photoreceptors, but not rods, express another Ca2+ sensor, S100B. This protein stimulates cyclic GMP synthesis as intracellular concentration of Ca2+ increases, and this modulation is specific to ROS-GC1, the only guanylate cyclase expressed in cones. Thus ROS-GC1 functions as a Ca2+-bimodal switch that increases its rate of cyclic GMP synthesis when intracellular Ca2+ rises to higher levels or falls to very low levels. We hypothesize that this bimodal feature serves cone function to better operate during daytime when cones are continuously light adapted and their function is to convey both light increments and decrements. While GCAP unimodal modulation of ROS-GC1 in rods provides negative feedback and is responsible primarily for accelerating response recovery, the GCAP/S100B bimodal feature can provide both negative and positive feedback, accelerating both the recovery and the rising phases.
James B. Ames
University of California, USA
Title: Structural Insights for Activation of Retinal Guanylate Cyclase by GCAP1
Time : 11:20-11:40
Biography:
Prof James B. Ames has completed his PhD from University of California, Berkeley Chemistry Department and postdoctoral studies from Stanford University School of Medicine. He is currently a Professor in the Chemistry Department. He has published more than 100 papers in reputed journals and has been serving as an editorial board member of Nature Scientific Reports and Frontiers in Molecular Neuroscience.
Abstract:
GCAP1, a member of the neuronal calcium sensor (NCS) subclass of the calmodulin superfamily, confers Ca2+-sensitive activation of retinal guanylyl cylcase 1 (RetGC1). I will present NMR resonance assignments, residual dipolar coupling (RDC) data, functional analysis, and a structural model of GCAP1 mutant (GCAP1V77E) in the Ca2+-free/Mg2+-bound activator state. NMR chemical shifts and RDC data reveal Ca2+-dependent differences for residues 170-174. An NMR-derived model of GCAP1V77E contains Mg2+ bound at EF2, and looks similar to Ca2+ saturated GCAP1 (RMSD = 2.0 Å). Ca2+-dependent structural differences occur in the fourth EF-hand (EF4) and adjacent helical region (residues 164-174 called the Ca2+-switch helix). Ca2+-induced shortening of the Ca2+-switch helix changes solvent accessibility of T171 and L174 that affects the domain interface. Although the Ca2+-switch helix is not part of the RetGC1 binding site, insertion of an extra Gly residue between S173 and L174 as well as deletion of R172, S173 or L174, all caused a decrease in Ca2+-binding affinity and abolished RetGC1 activation. We conclude that Ca2+-dependent conformational changes in the Ca2+ switch helix are important for activating RetGC1, and provide further support for a Ca2+-myristoyl tug mechanism.
Saravanan Kolandaivelu
West Virginia University Eye Institute, USA
Title: AIPL1, a protein linked with blinding diseases has distinct roles in rod and cone photoreceptor neurons
Time : 11:40-12:00
Biography:
Saravanan Kolandaivelu completed his graduate program at All India Institute of Medical Sciences (AIIMS), New Delhi, India. He then joined Dr. John Glomset’s group at Biochemistry, University of Washington as Howard Hughes Medical Institute Fellow and then developed his interest in vision research during his tenure as a senior biochemist with Dr. Visvanathan Ramamurthy at West Virginia University. He was then promoted to the rank of Research Assistant Professor in the department of Ophthalmology at West Virginia University. He currently studies the importance of post-translational lipid modification of proteins and its role in retinal function. He was the recipient of a pediatric ophthalmology grant from Knights Templar Eye Foundation. He was also awarded prestigious young investigator travel awards from NIH and FASEB awards to attend national meetings. He published more than 20 papers in reputed journals. Currently, his laboratory is interested in understanding the molecular mechanism behind the role for protein palmitoylation in photoreceptor function.
Abstract:
Retinal photoreceptor neurons are polarized cells with specialized ciliary extensions called outer segments (OS) needed for vision. Modulation of cGMP in the OS by light is essential for our visual perception. Regulation of cyclic GMP (cGMP) in photoreceptors neurons (rod and cones) is controlled by retinal guanylate cyclase (GC), which produce cGMP. Phosphodiesterase 6 (PDE6) is responsible for hydrolyzing cGMP to GMP upon light activation. Previously, we showed that Aryl hydrocarbon receptor Interacting Protein Like-1 (AIPL1), a protein linked with childhood blindness is needed for rod vision. Our studies show that the loss of AIPL1 in rod cells leads to reduced levels of PDE6 and consequent increase in cGMP that is thought to be the culprit behind rapid death of rod photoreceptor cells. The levels of GC, a cyclase needed for synthesis of cGMP in rods remain unaltered. Similar to rods, AIPL1 is needed for cone-mediated visual response. However, in contrast to rods, cones lacking AIPL1 display severe loss of cone PDE6 and GC. The reduction in enzymes mediating cGMP metabolism is accompanied by reduced levels of cGMP. The link between cGMP levels and rod / cone degeneration remains ambiguous and is currently under investigation.
Thomas Rich
University of South Alabama, USA
Title: Innovations in hyperspectral imaging approaches allow simultaeous measurement of the kinetics and spatial spread of cyclic nucleotide signals
Time : 12:00-12:20
Biography:
Thomas C. Rich received his B.A.E. and M.Sc. in Aerospace Engineering from the Georgia Institute of Technology in 1988 and 1990, and his Ph.D. in Biomedical Engineering from Vanderbilt University in 1996. He is currently a Professor in the Center for Lung Biology and Department of Pharmacology at the University of South Alabama College of Medicine. His research interests include the development of novel approaches to measure second messenger signals in real time, understanding mechanisms underlying signal specificity, and the roles of intracellular signaling pathways in pulmonary physiology and pathophysiology.
Abstract:
Cyclic nucleotides are ubiquitous second messengers known to differentially regulate many cellular functions over a wide range of timescales. Several lines of evidence suggest that intracellular distributions of cAMP and cGMP are not uniform, and that compartmentalization is largely responsible for signaling specificity within the these signaling pathways. However, real time measurements of cAMP and cGMP signals have been hampered by the low signal-to-noise ratio of fluorescence and FRET probes, as well as the inability to simultaneously measure multiple signals at discrete subcellular localtions within the same cell. In addition, measurements are typically performed in two spatial dimensions (2D), further limiting insight into second messenger signaling systems. Here we present novel hyperspectral imaging approaches that increase signal-to-noise ratios of fluorescence and FRET probes and allow real time, multiplexed measurements of intracellular signaling pathways in three spatial dimensions (3D). We have used hyperspectral approaches to visualize cyclic nucleotide gradients in several cell types, including pulmonary endothelial cells. Interestingly, in endothelial cells gradients primarily form along the apical to basolateral axis. These gradients would not be discerned by traditional imaging approaches. These data suggest that 2D imaging studies of cyclic nucleotide compartmentalization may lead to erroneous conclusions about the existence of second messenger gradients, and that 3D studies are required to assess mechanisms of signaling specificity. Results also demonstrate that novel hyperspectral imaging technologies are powerful tools for measuring biochemical processes in discrete subcellular domains. This work was supported by NIH grants P01HL066299, S10RR027535, and the Abraham Mitchell Cancer Research Fund.
Boris Tchernychev
Ironwood Pharmaceuticals Inc., USA
Title: Pharmacology of the Guanylate Cyclase-C agonist Linaclotide
Time : 12:20-12:40
Biography:
Boris Tchernychev received his M.Sc. degree in Biophysics from the Department of Biology of Moscow State University. After completing his PhD in Biochemistry at the Weizmann Institute of Science and his postdoctoral training in the laboratory of B. Furie (Beth Israel Deaconess Medical Center), Boris joined the biotech industry where he spent the last 10 years supporting multiple drug discovery and development programs in different therapeutic areas. At present Boris is a Principal Investigator at Ironwood Pharmaceuticals, where his research is focused on further understanding the secretory and pain inhibitory mechanisms of the FDA-approved drug LINZESS (Guanylate Cyclase-C agonist linaclotide).
Abstract:
Linaclotide is a 14-amino acid, minimally bioavailable peptide agonist of Guanylate Cyclase-C (GC-C) approved for treatment of adult patients with Irritable Bowel Syndrome with Constipation and Chronic Idiopathic Constipation. Linaclotide stimulation of GC-C expressed on the intestinal epithelium initiates signaling pathways resulting in improvement of spontaneous bowel movement and symptoms of abdominal pain. The effect of linaclotide on bowel movements is hypothesized to be a result of increased fluid secretion mediated by elevated intracellular cGMP levels following linaclotide binding to GC-C. Previous studies in enterocytes demonstrate that cGMP activates PKGII, leading to phosphorylation of CFTR and NHE3, both located on the apical membrane of enterocytes. PKGII phosphorylation alters the activity and cellular localization of both transporters and results in increased intraluminal concentrations of Cl-, HCO3- and Na+ ions, generating an electrolyte gradient that drives the passive efflux of water into the lumen, thereby accelerating transit. The effects of linaclotide on abdominal pain are hypothesized to be mediated by extracellular cGMP, which decreases the activity of pain-sensing nerves in nonclinical models. Linaclotide stimulation of rat colonic mucosa induces cGMP efflux from both the apical and the basolateral membrane. Efflux of cGMP from the apical membrane is mediated by Multidrug Resistance Protein 4 (MRP4). Inhibition of MRP4-dependent cGMP efflux by MK571 results in accumulation of intracellular cGMP and increased transepithelial ion current, induced by linaclotide. In summary, these data suggest the presence of a novel, previously unrecognized mechanism that functionally couples the secretory GC-C/cGMP pathway to spatially restricted modulation by apical MRP4.
Elangovan Vellaichamy
University of Madras, India
Title: Differential regulation of membrane bound guanylyl cyclases (GC) during β-adrenergic receptor activation- induced hypertrophic growth in rats
Time : 12:40-13:00
Biography:
Dr.Elangovan Vellaichamy has completed his M.Phil and PhD (Biochemistry) degree from University of Madras, India, and postdoctoral studies from; 1) Hebrew University of Jerusalem, Isreal, 2) The Celveland Clinc Foundation, Cleveland, Ohio, and 3) Tualne University of Health Sciences, Louisiana, USA. He is presently workig as a Professor, Department of Biochemsitry, University of Madras, Chennai, India. He has published more than 45 papers. His area of research interest is on; 1) Natriurteic Peptides and its Receptro System of the heart, and 2) undertanding the disease mechanisms of hypertension, cardiac hypertrophy and hear failure.
Abstract:
The natriuretic peptides (NPs) family is consists of three important peptides namely atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). ANP and BNP elicits its physiological action by specific binding to Natriureitc Peptide Receptor-A/Guanylyl cyclase-A (NPR-A/GC-A), while CNP binds to Natriureitc Peptide Receptor-B/ Guanylyl cyclase-B (NPR-B/ GC-B). Recent studies have suggested that ANP/NPR-A/GC-A and CNP/NPR-B/GC-B system are present in the heart as a negative regulatory mechanisms to antagonize the cardiac growth response to hypertrophic stimuli. Since NPs has the potential to inhibit cardiac hypertrophic growth via NPR-A/NPR-B receptors, understanding the regulation and expression of NPR-A and –B in the heart during the diseased conditions will help to target specific NPRs subtype to increase the physiological actions of NPs, and thus may be useful as therapy for cardiac hypertrophy and heart failure. In this context, we have studied left ventricular (LV) expression of NPR-A and NPR-B, and the functional activity of these receptors during β-adrenergic receptor (β-AR) activation induced hypertrophic growth in experimental rats. The NPR-A expression was markedly reduced (3.5-fold), while the NPR-B expression was up regulated (4-fold) in Isoproterenol (ISO)-treated heart as compared with controls.. Further, in-vitro membranes assay shows that NPR-A dependent guanylyl cyclase (GC) activity was down-regulated (2-fold), whereas NPR-B dependent GC activity was increased (5-fold) in ISO treated hearts. β –blocker (atenolol) treatment normalized the altered expression of NPR-A and –B proteins. Our results suggests that the chronic β-AR activation differentially regulates NPR-A/GC-A and NPR-B/GC-B in the heart. The signifcance of this finding will be discussed during the presentation.
Ana Méndez
University of Barcelona, Spain
Title: Identification of novel interacting partners of the RetGC1/GCAPs complex responsible for cGMP synthesis in photoreceptor cells of the retina: implications for cell physiology and disease
Time : 13:40-14:00
Biography:
Ana Méndez obtained her PhD from the Autonomous University of Madrid (UAM), Spain, and completed her postdoctoral studies at the Zilkha Neurogenetic Institute, Keck school of Medicine of the University of Southern California. She is currently an Associate Profesor at the University of Barcelona (UB), Spain, where she focuses on studying cell signaling and trafficking pathways in photoreceptor cells of the retina, and their connection to inherited retinal dystrophies.
Abstract:
To gain insight into the organization, assembly and trafficking of the RetGC1/GCAPs complex responsible for cGMP synthesis in rods and cones, as well as its modulation in vivo, we set to identify new interactors of Guanylate Cyclase Activating Protein 1 (GCAP1). Pull-down assays were performed with purified GCAP1 in its Ca2+-bound or Ca2+-free form, from bovine rod outer segment preparations. Bound proteins were identified by liquid chromatography and mass spectrometry (LC-MS/MS). A label-free quantitative proteomic analysis was performed to identify proteins with preferential affinity for one of the GCAP1 conformational forms. Thirty-seven proteins were identified with a fold change >3 for Ca2+-bound over Ca2+-free GCAP1. These proteins included several proteins that could have relevant implications for protein stability, ciliary trafficking and disease. Interestingly, we identified very robustly proteins involved in de novo synthesis of GTP. Co-localization of these enzymes with RetGC1 and GCAP1 was observed at the rod outer segment compartment in bovine retinal sections. Extensive biochemical analysis (size-exclusion chromatography of native tissue, crossed immunoprecipitation and pull-down assays and surface plasmon resonance analysis of the binding kinetics) have further confirmed some of these interactions, which involve direct interactions with RetGC1. Our results unveil an interplay between the RetGC/GCAPs complex responsible for cGMP synthesis and the complex responsible for de novo synthesis of GTP. We speculate that this supraorganization of multienzyme complexes could serve to channel nucleotide metabolism, with an integrated modulation depending on the dark/light physiology of the cell.
Ichiro N. Maruyama
Okinawa Institute of Science and Technology, Japan
Title: Environmental alkalinity sensing mediated by the transmembrane guanylyl cyclase GCY-14 in C. elegans
Time : 14:00-14:20
Biography:
Ichiro Maruyama is a Professor at the Okinawa Institute of Science and Technology Graduate University (OIST). He received his Ph.D. from The University of Tokyo, Japan. Subsequently he was trained as a post-doctoral fellow in MRC Laboratory of Molecular Biology, Cambridge, UK, where he started to work on the nematode Caenorhabditis elegans with an interest in its nervous system. He then moved to The Scripps Research Institute, La Jolla, California, USA, where he started to study molecular mechanisms underlying activation of cell-surface receptors. At OIST, Ichiro Maruyama continues to work on learning, memory and decision-making in C. elegans as well as on molecular mechanisms of transmembrane signaling mediated by cell-surface receptors.
Abstract:
Survival requires that living organisms continuously monitor environmental and tissue pH. Animals sense acidic pH using ion channels and G-protein-coupled receptors (GPCRs), but monitoring of alkaline pH is not well understood. We report here that in the nematode Caenorhabditis elegans, a transmembrane receptor-type guanylyl cyclase (RGC), GCY-14, of the ASEL gustatory neuron, plays an essential role in the sensing of extracellular alkalinity. Activation of GCY-14 opens a cGMP-gated cation channel encoded by tax-2 and tax-4 genes, resulting in Ca2+ entry into ASEL. Ectopic expression of GCY-14 in other neurons indicates that it accounts for the alkalinity sensing capability. Domain-swapping and site-directed mutagenesis of GCY-14 reveal that GCY-14 functions as a homodimer, in which histidine of the extracellular domains plays a crucial role in alkalinity detection. The Ca2+ entry into the cilia of ASEL induces depolarization of the cilial membrane potential, which in turn activates L-type voltage-gated Ca2+ channels containing an EGL-19 ï¡ subunit for active propagation of electrical signals in the dendrite. These results argue that in addition to ion channels and GPCRs, RGCs also play a role in pH sensation in neurons.
Frans Vinberg
Washington University School of Medicine, USA
Title: The Role of GCAP1 and GCAP2 in Regulating the Retinal Guanylate Cyclase And Phototransduction in Mammalian Cones
Time : 14:20-14:40
Biography:
Dr. Frans Vinberg received his M.Sc. and Ph.D. in Biomedical Engineering from Aalto University School of Science in Finland. He is currently a Postdoctoral Fellow at Washington University in St. Louis in Dr. Kefalov’s laboratory. He recently received an NIH/NEI Pathway to Independence K99 award. Dr. Vinberg is interested in understanding the molecular mechanisms that could explain the differences in the physiology of rod and cone photoreceptors mediating our nighttime and daytime vision, respectively. Furthermore, he wants to understand how defects in the function of retinal cells lead to blinding diseases. Specifically, Dr. Vinberg is focused on determining how Ca2+ feedback and regulation mechanisms contribute to the biology and pathobiology of mammalian photoreceptors
Abstract:
Absorption of a photon by visual pigment molecule in the photoreceptor outer segment (OS) triggers a G protein signaling cascade that leads to accelerated rate of cGMP hydrolysis, decline in cGMP concentration and reduced Na+ and Ca2+ influx via cGMP-gated cation channels (CNG channels). However, Ca2+ extrusion from the OS by Na+/Ca2+, K+ exchangers persists, causing photoactivation-induced decrease in Ca2+ concentration. The resulting Ca2+–dependent modulation of cGMP synthesis is critical for the ability of photoreceptors to adapt to background light. Retinal Guanylate Cyclases (RetGC) synthetize cGMP in both rod and cone photoreceptors. The activity of RetGCs is regulated by Guanylate Cyclase Activating Proteins (GCAP) in calcium-dependent manner. As background light intensity increases and Ca2+ concentration decreases, the active EF hand binding sites of GCAPs become occupied by Mg2+ instead Ca2+. These Mg2+-GCAPs activate RetGCs, thus accelerating the synthesis of cGMP. Recent studies have shown that both GCAP1 and GCAP2 are involved in modulating rod phototransduction. However, the distinct contributions of GCAP1 and GCAP2 to the physiology of mammalian cones have not been studied. Here we used electrophysiological recordings from mouse retina to investigate how Ca2+ feedbacks via GCAP1 and GCAP2 regulate cGMP and CNG channel current as well as phototransduction and light adaptation in intact mammalian cones. Our results demonstrate that, unexpectedly, GCAP2 can contribute significantly to the regulation of cGMP concentration and light adaptation in mammalian cones at least in the absence of GCAP1.
Venkateswar Venkataraman
Rowan University, USA
Title: Neurocalcin Delta/Membrane Guanylate Signaling Contributes to Circadian Rhythms
Time : 14:40-15:00
Biography:
Venkataraman received his M.S. from Madurai Kamaraj University, India and his PhD for the Indian Institute of Science, India. He is currently an Assistant Professor in the Department of cell Biology, Rowan SOM. He has published more than 50 papers and book chapters.
Abstract:
Circadian rhythms govern several important physiological processes. The endogenous body clock, which resides in the suprachiasmatic nucleus, is entrained by several zeitgebers, including light. Disruption of the endogenous clock or phase results in severe dyshomeostasis as observed during jet lag or in shift workers. It has been documented that cyclic GMP plays a critical role in setting the phase in circadian rhythms. However, the molecular mechanism by which it is regulated is unclear. The results from this study suggest that membrane guanylate cyclase is the likely source in the suprachiasmatic nucleus. Further evidence is presented that the likely regulator of this activity is the Neuronal Calcium Sensor protein, neurocalcin delta. It si proposed that the neurocalcin delta/membrane guanylate cyclase system enables a tight coupling to calcium, which is already an established regulator of generation and maintenance of circadian rhythms.
- Special Session
Location: Hilton San Antonio Airport
Session Introduction
Nachum Dafny
The University of Texas Health Science Center at Houston, USA
Title: Does Ritalin have the potential to become a drug of abuse?
Time : 09:25-10:05
Biography:
Nachum Dafny received his MS and PhD degrees from Hadassah Medical School in Jerusalem in 1965 and 1969, respectively followed by post-docs at Caltech, UCLA, and Columbia. He is currently a Professor of Neurobiology at the University of Texas Medical School at Houston.
Abstract:
The prefrontal cortex (PFC) is involved in complex planning, learning, memory, attention and integrates sensory information. It was reported that the PFC is dysfunctional in attention deficit hyperactivity disorder (ADHD). Methylphenidate (MPD), a drug often prescribed for the treatment of ADHD, has potential for abuse and misuse. Most MPD studies were completed in adult subjects; however most users are adolescents. The objective of this study was to investigate the acute and chronic dose response characteristics of MPD on PFC neuronal activity recorded in freely behaving adolescent rats. Four groups of animals were used: saline (control), 0.6, 2.5, and 10 mg/kg MPD. Acute MPD elicited a dose response increase in animals’ locomotor activity. Rechallenge with MPD at experimental day (ED10) when compared to the effect of MPD at ED1 showed no significant differences. When the animals were divided into two groups based on their individual responses to chronic MPD exposure, some animals expressed behavioral tolerance and some expressed behavioral sensitization. Electrophysiologically, a dose response characteristic for acute and chronic MPD exposure was observed. With increasing MPD doses, more PFC units responded by changing their firing rate. Moreover, the neuronal responses to chronic MPD recorded from animals expressing behavioral tolerance were significantly different compared to the neuronal population responses recorded from animals expressing behavioral sensitization. The majority of the PFC units recorded from animals expressing behavioral tolerance responded to MPD predominately by decreasing their firing rates, whereas PFC units recorded from behaviorally sensitized animals mainly showed an increase in their firing rates.
Nachum Dafny
The University of Texas Health Science Center at Houston, USA
Title: Does Ritalin have the potential to become a drug of abuse?
Biography:
The prefrontal cortex (PFC) is involved in complex planning, learning, memory, attention and integrates sensory information. It was reported that the PFC is dysfunctional in attention deficit hyperactivity disorder (ADHD). Methylphenidate (MPD), a drug often prescribed for the treatment of ADHD, has potential for abuse and misuse. Most MPD studies were completed in adult subjects; however most users are adolescents. The objective of this study was to investigate the acute and chronic dose response characteristics of MPD on PFC neuronal activity recorded in freely behaving adolescent rats. Four groups of animals were used: saline (control), 0.6, 2.5, and 10 mg/kg MPD. Acute MPD elicited a dose response increase in animals’ locomotor activity. Rechallenge with MPD at experimental day (ED10) when compared to the effect of MPD at ED1 showed no significant differences. When the animals were divided into two groups based on their individual responses to chronic MPD exposure, some animals expressed behavioral tolerance and some expressed behavioral sensitization. Electrophysiologically, a dose response characteristic for acute and chronic MPD exposure was observed. With increasing MPD doses, more PFC units responded by changing their firing rate. Moreover, the neuronal responses to chronic MPD recorded from animals expressing behavioral tolerance were significantly different compared to the neuronal population responses recorded from animals expressing behavioral sensitization. The majority of the PFC units recorded from animals expressing behavioral tolerance responded to MPD predominately by decreasing their firing rates, whereas PFC units recorded from behaviorally sensitized animals mainly showed an increase in their firing rates.
Abstract:
Nachum Dafny received his MS and PhD degrees from Hadassah Medical School in Jerusalem in 1965 and 1969, respectively followed by post-docs at Caltech, UCLA, and Columbia. He is currently a Professor of Neurobiology at the University of Texas Medical School at Houston.
- Track 2: Molecular Neuropharmacology
Track 3: Clinical Neuropharmacology
Track 10: Alzheimer’s Disease and Dementia
Track 11: Parkinson’s Disease
Location: Hilton San Antonio Airport
Session Introduction
Magnus S Magnusson
University of Iceland, Iceland
Title: Why search for hidden repeated temporal behaviour patterns? T-pattern Analysis (TPA) with Theme
Time : 14:40-15:00
Biography:
Magnus S Magnusson is a Research Professor, and did his PhD in 1983 from University of Copenhagen. He is the creator of the T-system model and algorithms implemented in Theme. Focus on real-time organization of behaviour, co-directed a two-year DNA analysis project, and published numerous papers. He was invited for talks at numerous conferences (including AIMS, IFNA, Neurotalk, Proteomics) and universities in Europe, USA and Japan. He was the Deputy Director in 1983-1988, at the Anthropology Laboratory, Museum of Natural History, Paris. He was repeatedly the invited Professor at Universities of Paris (V,VIII,XIII). Since 1991, he was the Founder and Director of the Human Behaviour Laboratory, University of Iceland. Since 1995, he was in collaboration between 24 universities based on “Magnusson’s analytical model” initiated at the Sorbonne, Paris.
Abstract:
Behavioral analysis has for long been characterized by the use of standard statistical methods developed in other contexts, that is, for quantitative analysis of particular other phenomena or any quantifiable phenomena. Moreover, often due to lack of tools, the counting of behavioural events and states and the measuring of their frequencies and durations has dominated. There has also been some use of multivariate statistics where clouds of points in n-dimensional (data) space reflect relations between behaviours and/or subjects. Hierarchical Cluster Analyses represent such relations in terms of hierarchies of clusters of clusters, however, generally, like with Factor Analysis, the clusters or factors do not describe patterns that recur in time like, for example, repeated words as patterns of letters (phonemes) and repeated phrases as patterns of words or rituals and routines such as greetings and meetings as patterns of simpler behaviours. Standard statistical methods such as sequential analysis are rarely used and typically imply over-simplifying assumptions that may prevent the detection of even abundant repeated patterns. The T-pattern model with its extensions, called the T-system, and corresponding detection algorithms and software, Theme (for Windows), were developed to make such pattern detection feasible and easily available even if computationally intensive. One reason for searching for complex repeated patterns is the possibility of thereby detecting effects of independent variables easily missed by other methods as research increasingly indicates in a number of areas including pharmacology and neuroscience. TPA with Theme allows the analysis of fairly voluminous data, but also of tiny data (just a few events) due to the particular and intensive use of temporal (discrete real-time) information. The T-pattern model with some of its extensions and corresponding algorithms is outlined together with illustrative applications and results.
Elzbieta Salinska
Polish Academy of Sciences, Poland
Title: Combining memantine with hypobaric hypoxia or hyperbaric oxygen does not generate additional neuroprotection in the model of birth asphyxia in 7-day-old rats
Time : 15:00-15:20
Biography:
Elzbieta Salinska has completed her PhD 25 years ago from Mossakowski Medical Research Centre, Polish Academy of Scienes in Warsaw. Since then she is a member of Neurochemistry Department and in 2010 became Head of Department. She has published 40 papers in reputed journals. Most of the papers concern studies on experimental models of brain ischemia. Part of the papers concern memory and learning, and are the result of 4 years of collaboration with The Open University, UK. Marcin Gamdzyk and Ewelina Bratek are PhD students supervised by E. Salinska. They both work on the experimental model of birth asphyxia.
Abstract:
Perinatal hypoxia-ischemia is one of the main causes of brain injury in neonates. Hypothermia is the only intervention clinically available and thus the challenge to establish new effective therapies remain a priority in neuroscience. Promising results have been observed using individual treatments of memantine (uncompetitive NMDA receptor antagonist), hyperbaric oxygen (HBO) or mild hypobaric hypoxia (HH) postconditioning. As combination therapies become recently a chance for better results, we decided to investigate whether the combination of memantine (20 mg/kg) treatment with HBO (2.5 ATA) or HH (0.47 ATA) would act synergistically on brain injury evoked by experimental model of birth asphyxia. 7-day old rats were subjected to hypoxia-ischemia (H-I) and then treated either with memantine, HBO, HH or combination of these treatments, started 1h or 6 h after H-I, and repeated for two subsequent days. Application of memantine, HBO or HH resulted in reduction in brain weight deficit, the size of infarct area and apoptosis. Reduction of chosen parameters accompanying oxidative stress was also observed. However, combining memantine with HBO treatment or HH postconditioning resulted in a loss of neuroprotective effects. In conclusion, our results show that memantine, HBO and HH applied separately shortly after H-I do provide neuroprotection, whereas combining memantine with HBO or HH, does not result in additive increase in the neuroprotective effect; on the contrary, combining the treatments increased neurodegeneration. This may suggest that treatments used in our study either compete acting towards the same elements or have the antagonistic effect on the intracellular mechanisms of neuroprotection.
Martin Horak
The Czech Academy of Sciences, Czech Republic
Title: Role of N-glycans on GluN sub-units in regulating endoplasmic reticulum processing, intracellular trafficking and gating of NMDA receptors
Biography:
Martin Horak has completed his PhD from The 2nd Faculty of Medicine, Charles University in Prague and Postdoctoral studies from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA. He is currently a Principal Investigator in the Institute of Physiology CAS, an academic non-profit research organization. He has published more than 20 papers in reputed journals and has been serving as an Evaluator of neuroscience and neuropharmacology research grants for the European Commission.
Abstract:
Glutamate is the principal excitatory neurotransmitter in the mammalian Central Nervous System (CNS). The primary ionotropic glutamate receptor subtypes are the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and N-methyl-D-aspartate receptors (NMDARs), which are present at the postsynaptic membrane of most excitatory synapses in the mammalian CNS. Our research is focused primarily on NMDARs. Nearly every protein that enters the endoplasmic reticulum lumen becomes N-glycosylated, including NMDARs; the glycans are then trimmed and replaced by more complex and variable glycan structures in the Golgi apparatus. However, the identity of the N-glycans that are present on the NMDARs and their role during the early trafficking and functioning of NMDARs have not yet been investigated in detail. Using biochemistry, confocal and electron microscopy, and electrophysiology in conjunction with a lentivirus-based molecular replacement strategy, we found that NMDARs are released from the ER only when two asparagine residues in the GluN1 subunit (N203 and N368) are N-glycosylated. Interestingly, other N-glycosylation sites in the GluN1, GluN2A, and GluN2B subunits do not play a critical role in the trafficking of NMDARs. Furthermore, we found that removing N-glycans from native NMDARs alters the receptor affinity for glutamate. We also revealed 21 lectins that can immunoprecipitate native NMDARs and AMPARs; moreover, two lectins are specific only for NMDARs. Finally, we showed that several lectins alter the functional properties of native NMDARs. Together, our findings suggest that NMDARs contain a specific composition of glycans that can be targeted in the development of novel pharmacological interventions.
Sidhartha Tan
University of Chicago, USA
Title: Human umbilical cord blood cells improve neurobehavioral outcome in a rabbit model of cerebral palsy
Time : 15:00-15:20
Biography:
Sidhartha Tan completed his MBBS from the All India Institute of Medical Sciences, India and is neonatologist and clinician scientist. He is Clinical Professor at Department of Pediatrics, NorthShore University HealthSystem and University of Chicago, IL. He investigates mechanisms of injury that result in cerebral palsy and mental retardation. He has developed an animal model that mimics cerebral palsy, one of the few models of its kind. His research has been continuously funded by NIH since 1992, and is now focused on bringing cures developed in the laboratory to the clinical realm to be used in human mothers and babies.
Abstract:
Cerebral palsy (CP) has significant impact on both patients and society. As there are no curative therapies for CP, stem cells have been proposed as a possible treatment. Human umbilical cord blood cells (HUCBC) containing stem and progenitor cells have been used to treat genetic brain diseases. Previously, HUCBC improved outcomes after hypoxic-ischemic injury in small animals. Clinical trials using HUCBC are underway for neonatal injury and CP. We tested HUCBC therapy in a rabbit model of CP following hypoxic-ischemic (H-I) injury. Following uterine ischemia at 70% gestation, we infused HUCBC in a randomized fashion to newborn rabbit kits after birth with either mild or severe neurobehavioral changes. Infusion of high dose HUCBC, 5x106 cells, dramatically altered the natural history of the injury alleviating the abnormal phenotype including posture, righting reflex, locomotion, tone, and dystonia. Half the high dose showed lesser but still significant improvement. The swimming test however showed that joint function did not restore to naïve control function in either group. Tracing HUCBCs with either MRI biomarkers or PCR for human DNA found little penetration of HUCBC in the newborn brain in the immediate newborn period, suggesting that the beneficial effects were not due to cellular integration or direct proliferative effects but rather to paracrine signaling. In a large animal model, HUCBC improves motor performance in a dose-dependent manner perhaps by improving compensatory repair processes.
Nicolas Marie
Neuroplasticity and Therapies of Addictions, CNRS, France
Title: Methadone blocks analgesic tolerance induced by morphine pretreatment
Time : 15:40-16:00
Biography:
During his PhD (obtained in 2003 from University Paris Descartes) Nicolas Marie worked on the cellular and molecular mechanisms (signaling, desensitization, receptor trafficking) of human delta opioid receptor regulation in the biochemistry laboratory of University Hospital Center of Caen ( France). Then, he moved to University College Cork (Ireland) as a post-doctoral fellow to work on the mechanisms of intracellular trafficking. In 2005 he joined the team of Dr. Florence as a CNRS scientist to work on preclinical research in drug (mainly cocaine and opiates) addiction using multipte approaches (cell biology, molecular and behavioral pharmacology, biochemistry).
Abstract:
Opiates such as morphine, are the most powerful analgesics however their protracted use is restricted by the development of tolerance to analgesic effects. Previous data suggest that the morphine inability to promote mu opioid receptor (MOPr) endocytosis could be at the origin of the tolerance and the co-injection of morphine with a MOPr internalizing reduces tolerance to morphine. So far, no studies have been conducted to evaluate the ability of methadone to reduce morphine tolerance in morphine-pretreated animals, a treatment sequence that could be encountered in opiate rotation protocol. We investigated the ability of methadone (a MOPr internalizing agonist used in therapeutic) to reverse morphine tolerance and the associated cellular mechanisms in the periaqueductal gray matter, a key region in pain control. Analgesic response was measured following a challenge dose of morphine in the hot plate test and regulation of MOPr (coupling and endocytosis) and some cellular mechanisms involved in tolerance such as adenylate cyclase superactivation and changes in N-methyl-d-aspartate (NMDA) receptor subunits expression and phosphorylation state were investigated. A chronic treatment with morphine promoted tolerance to its analgesic effects and was associated with a absence of MOPr endocytosis, adenylate cyclase overshoot, NR2A and NR2B down-regulation and NR1 phosphorylation. We found that a methadone treatment in morphine-treated mice reversed morphine tolerance to analgesia by promoting MOPr endocytosis and blocking cellular mechanisms of tolerance. Our data might lead to rational strategies to tackle opiate tolerance in the frame of opiate rotation.
Hideo Tsukada
Central Research Laboratory, Hamamatsu Photonics K.K., Japan
Title: PET imaging of ischemia-induced impairment of mitochondrial complex I function in living brain
Time : 16:15-16:35
Biography:
Hideo Tsukada received PhD from Shizuoka College of Pharmacy, Japan. He was a visiting researcher in Uppsala University PET Center, directed by Professor Bengt Langstrom, from 1990 to 91. At present, he is the senior manager of PET Center, Central Research Laboratory, Hamamatsu Photonics, Japan, and conducting PET researches in preclinical to clinical stages. He has published more than 250 papers, being awarded by the Society for Nuclear Medicine (2009), and Japan Molecular Imaging Award (2010). He is serving as the visiting Professor in Hamamatsu University School of Medicine, and University of Shizuoka, School of Pharmaceutical Sciences.
Abstract:
FDG-PET is a well-established technique for quantitative imaging of the regional cerebral metabolic rate of glucose (rCMRglc) in living brain. However, 18F-FDG is taken up into not only normal tissues but also inflammatory regions with microglial activation, which humpers the accurate diagnose of brain function. To solve this problem, the translational research with 18F-BCPP-EF, a novel PET probe for mitochondrial complex 1 (MC-1) activity was conducted using an animal PET in ischemic brains of Cynomolgus monkeys. Focal ischemia was induced by the right middle cerebral artery occlusion for 3 hr, then PET scans were conducted 7 days post ischemic insult with 15O-gases for regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of oxygen (rCMRO2), and 18F-BCPP-EF for MC-1, 11C-PBR28 for inflammation (TSPO), and 18F-FDG for rCMRglc. The total distribution volume (VT) values of 18F-BCPP-EF demonstrated the significant reduction of MC-1 activity in the damaged area at Day-7. The VT values of 18F-BCPP-EF provided better correlation with rCMRO2 than rCBF. In the inflammatory regions of the ischemic hemisphere detected with 11C-PBR28, higher 18F-FDG uptake and lower VT of 18F-BCPP-EF, and rCMRO2 than those in normal contralateral hemisphere were observed. Furthermore, the neuroprotective effect of FK506-liposome was detected by 18F-BCPP-EF, as improved MC-I activity, in ischemic-damaged regions. These results strongly suggested that the PET scan using 18F-BCPP-EF could non-invasively diagnose the extent of the brain damage and evaluate the neuroprotective effects without any disturbances by neuroinflammation, where 18F-FDG could not, owing to its high uptake into the activated microglia.
Annett Kunkel
Asklepios Kliniken GmbH, Germany
Title: Impact of natalizumab treatment on fatigue, mood and aspects of cognition in relapsing-remitting MS
Time : 16:35-16:55
Biography:
Dr. Annett Kunkel has completed her PhD in 1999 at the Humboldt-University in Berlin, Germany in the field of motor recovery in chronic stroke patients (Constraint-induced movement therapy). From 1999 to 2001 she completed a secondary education as Clinical Neuropsychologist. Since this time she works up to three years in the neurological rehabilitation and since 15 years in the area of acute neurology. During this time she began her research in patients with Multiple Sclerosis. For almost 5 years she is the leading Neuropsychologist in two neurological partner hospitals (Dept. of Neurology Asklepios Fachklinik Teupitz/Lübben).
Abstract:
Background/Objective: Fatigue, cognitive and affective disorders are relevant symptoms in Multiple Sclerosis (MS). The treatment with natalizumab has a positive effect on physical disabilities in patients with RRMS. Some studies describe improvements in cognition and fatigue over one year of treatment. Only little is known about longer treatment effects especially on fatigue, but also on cognition and mood. Therefore the present prospective open label observational study investigates the effect of natalizumab on fatigue, attention and depression over a treatment period of two years. Methods: 52 patients with RRMS (male=11, female=41; mean age: 33.9+9.1 years) underwent a comprehensive neuropsychological assessment, consisting on different tests of attention (TAP: alertness, divided attention, flexibility, SDMT, PASAT), fatigue (WEIMUS, FSMC) and depression (ADS-L). The assessments occurred immediately before the first administration of natalizumab, after one and two years of treatment. Results: Significant improvements were found in aspects of attention and depression from baseline to follow-up 1 (alertness: reaction time (RT) cued, p=0.02; divided attention: visual RT, p=0.02; SDMT: p=0.02; ADS-L: p=0.047) and from baseline to follow-up 2 (divided attention: visual RT: p=0.000; errors, p=0.01, omissions, p=0.05; flexibility: RT, p=0.05; SDMT: p=0.01; ADS-L: p=0.02). Up to know no significant changes were detected in fatigue probably because of the small sample size especially in the second year of treatment (WEIMUS: N=19, FSMC: N=7). Conclusion: The results show a positive effect of natalizumab on attention in patients with RRMS and for the first time also in depression after two years of observation and support the efficacy of the treatment over two years. More research is needed for fatigue.
Jin-Song Bian
National University of Singapore, Singapore
Title: Hydrogen sulfide attenuates opioid withdrawal-induced jumping and pain sensitization
Time : 16:55-17:15
Biography:
Jin-Song Bian is an Associate Professor in Department of Pharmacology, Yong Loo Ling School of Medicine, National University of Singapore, Singapore. He earned his PhD degree from the University of Hong Kong. At Albert Einstein College of Medicine in USA, he completed his Post-doctoral training with an American Heart Association fellowship in 2003. His main research interest is biology of endogenous mediators (e.g. hydrogen sulfide). He has published over 80 papers in international journals including Cir Res, ARS, JASN.
Abstract:
Addiction to opioid drugs is a serious clinical and social problem. Withdrawal-induced symptoms are the main cause of keeping drug-dependent individuals craving for continued opioids. Hydrogen sulfide (H2S) is a novel endogenous neuromodulator. The role of H2S in opioid induced syndrome was investigated in the present study. We found that exogenous application of NaHS, an H2S donor, significantly alleviated naloxone-precipitation induced robust withdrawal jumping in mice. Application of NaHS or stimulation of endogenous H2S production suppressed naloxone precipitation induced cAMP rebound and CREB phosphorylation. Our data suggest that H2S may produce beneficial effects against opioid addiction by suppression of AC/cAMP /CREB pathway. Hyperalgesia often occurs in opioid-induced withdrawal syndrome. In the present study, we also studied the effect of H2S on opioid withdrawal induced hyperalgesia. We found that application of NaHS together with three hourly injections of DAMGO (a μ-opioid receptor agonist) attenuated naloxoneprecipitated withdrawal hyperalgesia. RT-PCR and Western blot analysis showed that NaHS significantly reversed the gene and protein expression of up-regulated spinal calcitonin gene-related peptide (CGRP) in naloxone-treated animals. NaHS also inhibited naloxone-induced cAMP rebound and cAMP response element-binding protein (CREB) phosphorylation in rat spinal cord. In addition, NaHS pre-treatment suppressed naloxone-stimulated activation of protein kinase C (PKC) α, Raf-1, and extracellular signal-regulated kinase (ERK) 1/2 in rat spinal cord. In conclusion, our data suggest that H2S prevents the development of opioid withdrawal induced symptoms via suppression of synthesis of CGRP through inhibition of AC/cAMP and PKC/Raf-1/ERK pathways.
Nasim Vousooghi
Tehran University, Iran
Title: Morphine experience in adult rats alters morphine preference and brain expression of dopamine receptors in F1 offspring
Time : 17:15-17:35
Biography:
Nasim Vousooghi became Pharm. D. At the age of 26 and completed her PhD of pharmacology at the age of 33 years from Shahid Beheshti University of Medical Sciences. She is working as assistant profesor and director of research deputy in the departement of neuroscience and addiction studies in Tehran University of Medical Sciences from 2010 till now. She is also the head of genetics laboratory of the Iranian National Center for addiction studies (INCAS). She has published more than 20 papers in prestigious journals.
Abstract:
Genetic and environmental factors are involved in opioid addiction. It is claimed that offspring of addicted people are more prone for drug addiction including opioids. However, the exact mechanisms involved in trans-generational effects of opioids are not much understood. Here we have studied the effects of parental opioid addiction on morphine preference and mRNA expression of dopamine receptors in F1 male offspring. Adult male and female Wistar rats received chronic morphine followed by two weeks drug free period before mating. Two-bottle- choice paradigm was used to measure morphine preference in offspring. The mRNA expression of dopamine receptors was evaluated in prefrontal cortex, nucleus accumbens, hippocampus, and striatum of F1 male animals by Real-Time PCR approach. The results showed that F1male offspring of morphine-exposed parents had higher preference for morphine consumption in comparison to offspring of saline-exposed parents. D1 and D5 dopamine receptors were significantly up-regulated in prefrontal cortex and nucleus accumbens of F1 male offspring of morphine-exposed parents. D5 and D2 receptors were, however, down-regulated in hippocampus. D4 dopamine receptor was up-regulated in hippocampus and striatum and down-regulated in prefrontal cortex. It is concluded that chronic morphine exposure of adult male and female rats before gestation leads to higher morphine preference in their F1male offspring. Furthermore, alterations in the expression of dopamine receptors in the reward pathway could be involved in observed changes in F1 offspring.
Ai-Ling Lin
University of Kentucky College of Medicine, USA
Title: Neuroimaging of rapamycin and prevention of Alzheimer’s disease for APOE4 carriers
Time : 17:35-17:55
Biography:
Ai-Ling Lin completed her PhD and Postdoctoral training as a medical physicist from the University of Texas Health Science Center at San Antonio. She is an Assistant Professor in the Sanders-Brown Center on Aging and Department of Pharmacology and Nutritional Sciences of the University of Kentucky. She has developed and applied multi-metric neuroimaging methods (MRI, MRS and PET) to identify effects of caloric restriction and rapamycin on cognitive aging and Alzheimer’s disease with various animal models. She has published more than 30 papers in reputed journals and continuously received funding from NIH.
Abstract:
Apolipoprotein E ε4 allele (APOE4) is strongest genetic risk facot for late-onset Alzheimer's disease (AD). Brain vascular and metabolic deficits can occur in cognitively normal APOE4 carriers decades before the onset of AD. The goal of this study was to determine whether early intervention using rapamycin could restore neurovascular and neurometabolic functions, and thus impede pathological progression of AD-like symptoms in pre-symptomatic APOE4 transgenic mice. Using in vivo, multimodal neuroimaging, we found that APOE4 mice treated with rapamycin had restored cerebral blood flow, blood-brain barrier integrity and glucose metabolism, compared to age- and gender-matched wild-type controls. The preserved vasculature and metabolism were associated with amelioration of incipient learning deficits. We also found that rapamycin restored the levels of the proinflammatory cyclophilin A in vasculature, which may contribute to the preservation of cerebrovascular function in the APOE4 transgenics. Our results show that rapamycin improves functional outcomes in this mouse model and may have potential as an effective intervention to block progression of vascular, metabolic and early cognitive deficits in human APOE4 carriers. As rapamycin is FDA-approved and neuroimaging is readily used in humans, the results of the present study may provide the basis for future AD intervention studies in human subjects.