AND (Association of the Study for Neurons and Diseases) Winter Mini-Conference -Joint conference with Innovative Area for Micro-endophenotypes of Psychiatry Disorders – Place; K K R A t a m i H o t e l Date; J an 2 2nd , 20 1 5 http://www.kkr-atami.gr.jp Each speaker has 40 min (30-35 min. talk and discussion) PM 1:00-1:05 Opening remarks by Min Zhuo (University of Toronto) PM 1:05-1:10 Introduction of Molecular Brain and Molecular Pain by Bong-Kiun Kaang (Seoul National University) Session 1 Chair; Bong-Kiun Kaang (Seoul National University) PM 1:10-1:50 Graham L. Collingridge (University of Bristol) Is Alzheimer’s disease caused by LTD gone awry? PM 1:50-2:30 Fusao Kato (Jikei University School of Medicine) Pain chronification and amygdala plasticity Session 2 Chair; Tsuyoshi Miyakawa (Fujita Health University) PM 2:45-3:25 Robert Nistico (Sapienza University of Rome) Synaptic plasticity in multiple sclerosis and in experimental autoimmune encephalomyelitis PM 3:25-4:05 Makoto Tominaga (Okazaki Institute for Integrative Bioscience) Functional Interaction between TRP channels and anoctamin1 Session 3 Chair; Satoshi Kida (Tokyo University of Agriculture) PM 4:20-5:00 Christopher Parsons (Merz Pharmaceuticals GmbH) Aβ as a target for drug development for Alzheimer’s disease PM 5:00-5:40 Yuichi Iino (The University of Tokyo) Memory formation by axonal transport of an insulin receptor isoform in Caenorhabditis elegans PM 5:40-6:20 Min Zhuo (University of Toronto) Cortical synaptic mechanisms for pleasure and pain PM 6:20-6:30 Introduction of Molecular Brain review series by Timothy Bliss PM 6:30-6:35 Conclusion remarks by Satoshi Kida PM 7:00-9:00 Reception dinner Title: Is Alzheimer’s disease caused by LTD gone awry? Name: Graham L. Collingridge Affiliation: Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, U.K E-mail: [email protected] Abstract: The purpose of our studies has been to identify the signalling cascades that are involved in N-methyl-D-aspartate (NMDA) receptor-mediated long-term depression (LTD) in the hippocampus. We wish to use this knowledge to establish how dysregulation of components of these pathways leads to synaptic injury and cognitive deficits in neurodegenerative diseases, such as Alzheimer's disease. Experiments were performed on acute and organotypic hippocampal slices prepared from juvenile rats. Proteins were targeted pharmacologically and using RNAi. Working with a variety of collaborators, we have identified the following pathways in NMDAR-LTD. GluA2 / NSF / hippocalcin Akt1 / GSK-3beta / tau PI3K JAK2 / STAT3 GIT1 / Arf-1 / PICK1 / Arp2/3 We propose that synaptic injury, an early event in AD, is caused, at least in part, by dysregulation of NMDAR- LTD. This process is normally involved in physiological synaptic pruning but in response to a variety of genetic or environmental influences can prune synapses in an aberrant manner. We propose that a fuller understanding of this mechanism should lead to better therapeutic strategies. Title: Pain chronification and amygdala plasticity Name: Fusao Kato Affiliation: Department of Neuroscience and Center for Neuroscience of Pain, Jikei University School of Medicine E-mail: [email protected] Abstract: The amygdala is the key structure playing essential roles in linking aversive sensory information and optimum behavioral outputs that would help the animal better survive. Of the subnuclei composing the amygdala, the central amygdala (CeA) receives two kinds of nociception-linked information: directly from the spino-parabrachial pathway and indirectly from the basolateral amygdala, thus effectively linking nociception and emotion (Veinante et al, 2013). A recent imaging study in human patients with persistent pain indicated that the increased spontaneous activity in the emotion-related structures such as the CeA is the core signature of consolidated chronic pain (Hashmi et al, 2013). I will present some of our recent findings in the latent chronification process of the inflammatory pain models observed >6 hours after subcutaneous formalin injection in rats and mice. The latent consequences included 1) aberrant decrease in nociceptive threshold in other regions of the body than the site of inflammation (“generalized sensitization”), 2) synaptic potentiation of LPB-CeA transmission in the right CeA as confirmed in isolated slices with optogenetic and electrical stimulation of the LPB afferents in a manner dependent of CGRP, and 3) increased selective uptake of Mn2+ to the CeA during spontaneous free moving after 6-24 hours post-injection as evidenced by Mn2+-enhanced MRI with ultra-high magnetic field MRI. The activation of the CeA by inflammatory/nociceptive information would be a key initiative process for pain chronification with various outcomes including the aberrantly enhanced nociception “The pain changes the brain and the brain changes the pain”. Title: Synaptic plasticity in multiple sclerosis and in experimental autoimmune encephalomyelitis Name: Robert Nisticò Affiliation: Department of Physiology and Pharmacology, Sapienza University of Rome E-mail: [email protected] Abstract: Multiple sclerosis (MS), a neuroinflammatory disorder characterized by demyelination and progressive axonal loss, is associated with early cognitive deficit, which has a significant impact on the quality of life of patients. Recent studies highlight the importance of inflammation-induced synaptic dysfunction in the very early phases of MS and in a mouse model of MS, the experimental autoimmune encephalomyelitis (EAE). We have recently shown that in EAE hippocampus long-term potentiation (LTP) is favored over long-term depression (LTD) in response to repetitive synaptic activation, through a mechanism dependent on enhanced IL-1β released from infiltrating lymphocytes or activated microglia. In addition, we have also demonstrated that platelet-derived growth factor (PDGF) plays a substantial role in favoring both LTP and brain reserve in MS patients, as this molecule: (1) was reduced in the CSF of PP-MS patients, (2) enhanced LTP in hippocampal mouse brain slices, (3) was associated with more pronounced LTP in RR-MS patients, and (4) was associated with the clinical compensation of new brain lesion formation in RR-MS. Overall these results suggest that brain plasticity reserve, in the form of LTP, might be crucial to contrast clinical deterioration in MS. Enhancing PDGF signaling might represent a valuable treatment option to maintain brain reserve and to attenuate the clinical consequences of neuronal damage in the progressive phases of MS and possibly in other neurodegenerative disorders. Title: Functional Interaction between TRP channels and anoctamin1 Name: Makoto TOMINAGA Affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience E-mail: [email protected] Abstract: Transient receptor potential (TRP) channels are nonselective cation channels with high Ca2+ permeability. We found physical and functional interaction between TRP vanilloid 4 (TRPV4) and anoctamin1 (ANO1), a Ca2+-activated chloride channel, in HEK293T cells and choroid plexus epithelial cells (CPECs). Chloride currents induced by a TRPV4 activator were markedly increased in an extracellular calcium-dependent manner in HEK293T cells expressing TRPV4 with ANO1 and in CPECs. We also found physical interaction between TRPV4 and ANO1 in both cell types. Cell volume changes were induced by ANO1-mediated chloride currents in parallel with membrane potential changes, and the cell volume was significantly decreased at negative membrane potentials by TRPV4-induced ANO1 activation. These physical and functional interactions between TRPV4 and ANO1 can modulate water transport in the choroid plexus. Next, we found similar physical and functional interaction between TRPV1 and ANO1 in HEK293T cells and mouse sensory neurons. Capsaicin-evoked inward currents were significantly inhibited by a specific ANO1 antagonist T16Ainh-A01 (A01) in mouse DRG neurons. In addition, capsaicin-evoked action potential was drastically inhibited by A01. Furthermore, pain-related behaviors in mice treated with capsaicin were significantly reduced by the concomitant administration of A01. These results indicate that the TRPV1-ANO1 interaction is a significant pain-enhancing mechanism in the peripheral nervous system. Thus, TRP channel/anoctamin complex could play many important roles in various tissues. Title: Aβ as a target for drug development for Alzheimer´s disease Name: Christopher G. Parsons Affiliation: Principal Scientific Expert – Pharmacology, Non-Clinical Science, Merz Pharmaceuticals GmbH, Eckenheimer Landstr. 100, D-60318 Frankfurt am Main, Germany E-mail: [email protected] Abstract: β-amyloid (Aβ) is widely accepted to be one of the major pathomechanisms underlying Alzheimer's disease (AD), although there is presently lively debate regarding the relative roles of particular species / forms of this peptide [1]. Most recent evidence indicates that soluble oligomers rather than plaques are the major cause of synaptic dysfunction and ultimately neurodegeneration in AD [2]. Soluble oligomeric Aβ has been shown to interact with several synaptic proteins, for example NMDA / mGluR5 glutamatergic receptors, postsynaptic anchoring proteins and uptake / release transporters responsible for maintaining glutamate homeostasis. Indeed both NMDA receptor antagonists such as memantine and Ro 25-6981 as well as the mGluR5 negative allosteric modulator MPEP are able to reverse oligomeric Aβ induced deficits in synaptic plasticity such as long term potentiation (LTP) [3]. Molecules that disrupt assembly of soluble Aβ oligomers or interfere with their binding to neuronal receptors represent a promising alternative approach for the treatment and possible prevention of AD. In our hands three classes of Aβ aggregation modulators, scyllo-inositol (AZD-103), the 8-hydroxyquinoline PBT2 and the dipeptide NH2-D-Trp-Aib-OH were also able to reverse such oligomeric Aβ induced synaptic deficits in LTP [4]. There is even considerable debate which particular Aβ oligomeric species are the most synaptotoxic with some champions of e.g. dodecameric assemblies (Aβ*56) whilst others claim that trimers and even dimers of Aβ are the most relevant pathogen in AD. This prompted us to look for molecules that interfere with Aβ oligomerization at its earliest step as potential disease modifying agents in AD. Identification of novel molecules that block Aβ assembly is performed at Merz using a proprietary Aβ oligomer specific, TR-FRET-based screen using Aβ1-42 at a low concentration of 200 nM. Hits are validated using a cell-based high content screen (HCS) that detects binding of patho-physiologically relevant concentrations (1-50 nM) of soluble oligomeric Aβ to hippocampal neuronal synapses. Validated hits are then tested for functional effects such as reversal of low nM Aβ oligomer-induced deficits in LTP in vitro [4] and then in vivo. Use of these TR-FRET and HCS assays has proven this screening platform to be very well suited for the identification of novel CNS drug-like Aβ assembly blockers. The knowledge acquired on the structural requirements for Aβ oligomer assembly inhibition was then applied to develop in silico (pharmacophore) models. These compound-based models were used to virtually screen large vendor compound libraries for new chemical entities with Aβ aggregation inhibitory properties. [1] “Molecular mechanisms of neurodegeneration in Alzheimer’s disease” Crews L and Masliah E; Hum Mol Genet. 2010 (19) R12-20 [2] “Soluble oligomers of the amyloid beta-protein impair synaptic plasticity and behavior” Selkoe DJ; Behav Brain Res. 2008 (192) 106-113 [3] “Therapeutic significance of NR2B-containing NMDA receptors and mGluR5 metabotropic glutamate receptors in mediating the synaptotoxic effects of β-amyloid oligomers on long-term potentiation (LTP) in murine hippocampal slices” Rammes G, Hasenjäger A, Sroka-Saidi K, Deussing JM, Parsons CG; Neuropharmacology 2011 (60) 982-990 [4] “Aggregation inhibitors reverse ß-amyloid induced inhibition of long term potentiation (LTP) in murine hippocampal slices” Rammes G, Hasenjäger A, Sroka-Saidi K, Parsons CG; Contribution to SfN’s 41st annual meeting. Washington DC, November 2011. Title: Memory formation by axonal transport of an insulin receptor isoform in Caenorhabditis elegans Name: Yuichi IINO Affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo E-mail: [email protected] Abstract: Insulin signaling plays conserved roles for representing feeding status in various animals. In addition, mammalian insulin signaling is suggested to be involved in learning and memory, but the precise mechanisms have been unclear. We have previously found that the insulin/PI 3-kinase pathway is essential for starvation-dependent learning called taste avoidance learning in C. elegans. While C. elegans fed under the presence of salt (NaCl) shows preference for salt, they learn to avoid salt by starvation in the presence of salt. We have previously found that the insulin/PI-3 kinase pathway in the sensory neuron is essential for the taste avoidance learning. Now we find that there are two major isoforms of the insulin receptor DAF-2, DAF-2a and DAF-2c, of which only DAF-2c can support learning. Interestingly, DAF-2c is preferentially localized to the synapse-rich axonal region, especially under starved conditions, and this localization is essential for its function in salt avoidance learning. Activation of PI 3-kinase pathway in the axonal region, but not elsewhere in the sensory neuron, using a photo-activatable probe, causes salt avoidance behavior in well-fed animals, suggesting that the localization of the receptor is a key for the formation of starvation memory. The C. elegans homologue of calsyntenin, a transmembrane protein implicated in Alzheimer's disease, acts as a cargo adaptor for axonal transport of DAF-2c. Title: Cortical synaptic mechanisms for pleasure and pain Name: Min Zhuo Affiliation: Department of Physiology, Faculty of Medicine, University of Toronto E-mail: [email protected] Abstract: Pleasure and pain are two major forms of emotion that affect our daily life. Both human beings and animals seek the pleasure, and try to avoid any potential dangerous or painful stimuli or environment. Recent human imaging and animal studies suggest that cortical regions such as the anterior cingulate cortex (ACC) and insular cortex (IC) play important roles in the process of positive (pleasure) and negative (pain) emotion. In this review, I will discuss some of recent progress, and explore possible synaptic mechanisms that mediate pain and pleasure in the cortex.
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