Blocking acid-sensing ion channel 1 alleviates Huntington's disease pathology via an ubiquitin-proteasome system-dependent mechanism.

Huntington's disease (HD) is a fatal neurodegenerative disorder. Despite a tremendous effort to develop therapeutic tools in several HD models, there is no effective cure at present. Acidosis has been observed previously in cellular and in in vivo models as well as in the brains of HD patients. Here we challenged HD models with amiloride (Ami) derivative benzamil (Ben), a chemical agent used to rescue acid-sensing ion channel (ASIC)-dependent acidotoxicity, to examine whether chronic acidosis is an important part of the HD pathomechanism and whether these drugs could be used as novel therapeutic agents. Ben markedly reduced the huntingtin-polyglutamine (htt-polyQ) aggregation in an inducible cellular system, and the therapeutic value of Ben was successfully recapitulated in the R6/2 animal model of HD. To reveal the mechanism of action, Ben was found to be able to alleviate the inhibition of the ubiquitin-proteasome system (UPS) activity, resulting in enhanced degradation of soluble htt-polyQ specifically in its pathological range. More importantly, we were able to demonstrate that blocking the expression of a specific isoform of ASIC (asic1a), one of the many molecular targets of Ben, led to an enhancement of UPS activity and this blockade also decreased htt-polyQ aggregation in the striatum of R6/2 mice. In conclusion, we believe that chemical compounds that target ASIC1a or pharmacological alleviation of UPS inhibition would be an effective and promising approach to combat HD and other polyQ-related disorders.

[1]  N. Mesaeli,et al.  Enhanced ubiquitin-proteasome activity in calreticulin deficient cells: a compensatory mechanism for cell survival. , 2008, Biochimica et biophysica acta.

[2]  Su-Youne Chang,et al.  Acid-sensing ion channels (ASICs) as pharmacological targets for neurodegenerative diseases. , 2008, Current opinion in pharmacology.

[3]  L. Fugger,et al.  Acid-sensing ion channel-1 contributes to axonal degeneration in autoimmune inflammation of the central nervous system , 2007, Nature Medicine.

[4]  Howard Schulman,et al.  Global changes to the ubiquitin system in Huntington's disease , 2007, Nature.

[5]  L. Kiedrowski.  NCX and NCKX Operation in Ischemic Neurons , 2007, Annals of the New York Academy of Sciences.

[6]  Rolf Gruetter,et al.  Neurochemical changes in Huntington R6/2 mouse striatum detected by in vivo1H NMR spectroscopy , 2007, Journal of neurochemistry.

[7]  A. Ciechanover,et al.  Narrative Review: Protein Degradation and Human Diseases: The Ubiquitin Connection , 2006, Annals of Internal Medicine.

[8]  John A. Wemmie,et al.  Acid-sensing ion channels: advances, questions and therapeutic opportunities , 2006, Trends in Neurosciences.

[9]  Nobuyuki Nukina,et al.  Expanded polyglutamines impair synaptic transmission and ubiquitin–proteasome system in Caenorhabditis elegans , 2006, Journal of neurochemistry.

[10]  Sagnella Ga,et al.  The Renal Epithelial Sodium Channel: Genetic Heterogeneity and Implications for the Treatment of High Blood Pressure , 2006 .

[11]  N. Mizushima,et al.  Generation of cell lines with tetracycline‐regulated autophagy and a role for autophagy in controlling cell size , 2006, FEBS letters.

[12]  N. Nukina,et al.  rAAV-mediated shRNA ameliorated neuropathology in Huntington disease model mouse. , 2006, Biochemical and biophysical research communications.

[13]  Elaine Holmes,et al.  Metabolic characterization of the R6/2 transgenic mouse model of Huntington's disease by high-resolution MAS 1H NMR spectroscopy. , 2006, Journal of proteome research.

[14]  Tian-Le Xu,et al.  Coupling between NMDA Receptor and Acid-Sensing Ion Channel Contributes to Ischemic Neuronal Death , 2005, Neuron.

[15]  F. Leenen,et al.  Blockade of brain mineralocorticoid receptors or Na+ channels prevents sympathetic hyperactivity and improves cardiac function in rats post-MI. , 2005, American journal of physiology. Heart and circulatory physiology.

[16]  N. Nukina,et al.  Decreased expression of hypothalamic neuropeptides in Huntington disease transgenic mice with expanded polyglutamine‐EGFP fluorescent aggregates , 2005, Journal of neurochemistry.

[17]  Y. Marunaka,et al.  Benzamil, a blocker of epithelial Na(+) channel-induced upregulation of artery oxygen pressure level in acute lung injury rabbit ventilated with high frequency oscillation. , 2005, Biochemical and biophysical research communications.

[18]  E. Bennett,et al.  Global impairment of the ubiquitin-proteasome system by nuclear or cytoplasmic protein aggregates precedes inclusion body formation. , 2005, Molecular cell.

[19]  R. Prost,et al.  Heterogeneity in 1H-MRS profiles of presymptomatic and early manifest Huntington's disease , 2005, Brain Research.

[20]  Christopher A Ross,et al.  The ubiquitin-proteasome pathway in Parkinson's disease and other neurodegenerative diseases. , 2004, Trends in cell biology.

[21]  M. Zhuo,et al.  Characterization of Acid-sensing Ion Channels in Dorsal Horn Neurons of Rat Spinal Cord* , 2004, Journal of Biological Chemistry.

[22]  Mark R. Segal,et al.  Inclusion body formation reduces levels of mutant huntingtin and the risk of neuronal death , 2004, Nature.

[23]  G. Bates,et al.  Huntingtin and the molecular pathogenesis of Huntington's disease , 2004, EMBO reports.

[24]  M. Welsh,et al.  Neuroprotection in Ischemia Blocking Calcium-Permeable Acid-Sensing Ion Channels , 2004, Cell.

[25]  G. Haddad,et al.  Calcium and pH homeostasis in neurons during hypoxia and ischemia. , 2004, Cell calcium.

[26]  F. Abboud,et al.  Extracellular acidosis increases neuronal cell calcium by activating acid-sensing ion channel 1a. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[27]  M. Beal,et al.  The Energetics of Huntington's Disease , 2004, Neurochemical Research.

[28]  O. Krishtal.  The ASICs: Signaling molecules? Modulators? , 2003, Trends in Neurosciences.

[29]  John A. Wemmie,et al.  Acid-Sensing Ion Channel 1 Is Localized in Brain Regions with High Synaptic Density and Contributes to Fear Conditioning , 2003, The Journal of Neuroscience.

[30]  W. Xiao,et al.  Generation and characterization of chimeric recombinant AAV vectors. , 2003, Molecular therapy : the journal of the American Society of Gene Therapy.

[31]  R. Fitzsimonds,et al.  Distribution, subcellular localization and ontogeny of ASIC1 in the mammalian central nervous system , 2003, The Journal of physiology.

[32]  S. Shimada,et al.  Amiloride-blockable acid-sensing ion channels are leading acid sensors expressed in human nociceptors. , 2002, The Journal of clinical investigation.

[33]  Keiji Tanaka,et al.  Selective Proteasomal Dysfunction in the Hippocampal CA1 Region after Transient Forebrain Ischemia , 2002, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[34]  John A. Wemmie,et al.  The Acid-Activated Ion Channel ASIC Contributes to Synaptic Plasticity, Learning, and Memory , 2002, Neuron.

[35]  M. Welsh,et al.  Heteromultimers of DEG/ENaC subunits form H+-gated channels in mouse sensory neurons , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[36]  Walther Akemann,et al.  Transgenic mice expressing a pH and Cl– sensing yellow‐fluorescent protein under the control of a potassium channel promoter , 2002, The European journal of neuroscience.

[37]  M. Lazdunski,et al.  Nonsteroid Anti-Inflammatory Drugs Inhibit Both the Activity and the Inflammation-Induced Expression of Acid-Sensing Ion Channels in Nociceptors , 2001, The Journal of Neuroscience.

[38]  E A Zemskov,et al.  Altered proteasomal function due to the expression of polyglutamine-expanded truncated N-terminal huntingtin induces apoptosis by caspase activation through mitochondrial cytochrome c release. , 2001, Human molecular genetics.

[39]  K. Prasad,et al.  Use of short-lived green fluorescent protein for the detection of proteasome inhibition. , 2001, BioTechniques.

[40]  Takeshi Tokuhisa,et al.  Dissection of Autophagosome Formation Using Apg5-Deficient Mouse Embryonic Stem Cells , 2001, The Journal of cell biology.

[41]  J. Keller,et al.  Oxidative Stress-Associated Impairment of Proteasome Activity during Ischemia–Reperfusion Injury , 2000, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[42]  I. Kanazawa,et al.  Caspase activation during apoptotic cell death induced by expanded polyglutamine in N2a cells. , 1999, Neuroreport.

[43]  K. Chiba,et al.  Activation of the proteasomes of sand dollar eggs at fertilization depends on the intracellular pH rise. , 1999, Developmental biology.

[44]  Xudong Huang,et al.  Dramatic Aggregation of Alzheimer Aβ by Cu(II) Is Induced by Conditions Representing Physiological Acidosis* , 1998, The Journal of Biological Chemistry.

[45]  B R Rosen,et al.  1H NMR spectroscopy studies of Huntington's disease , 1998, Neurology.

[46]  Mark Turmaine,et al.  Formation of Neuronal Intranuclear Inclusions Underlies the Neurological Dysfunction in Mice Transgenic for the HD Mutation , 1997, Cell.

[47]  M. Lazdunski,et al.  A proton-gated cation channel involved in acid-sensing , 1997, Nature.

[48]  A. Ludolph,et al.  Decreased N-acetyl-aspartate/choline ratio and increased lactate in the frontal lobe of patients with Huntington's disease: a proton magnetic resonance spectroscopy study. , 1997, Journal of neurology, neurosurgery, and psychiatry.

[49]  S. W. Davies,et al.  Exon 1 of the HD Gene with an Expanded CAG Repeat Is Sufficient to Cause a Progressive Neurological Phenotype in Transgenic Mice , 1996, Cell.

[50]  M. Rechsteiner,et al.  A Proteasome Activator Subunit Binds Calcium (*) , 1995, The Journal of Biological Chemistry.

[51]  H. Yokosawa,et al.  Intracellular calcium mobilization regulates the activity of 26 S proteasome during the metaphase-anaphase transition in the ascidian meiotic cell cycle. , 1994, Developmental biology.

[52]  B. Rosen,et al.  Evidence for irnnairment of energy metabofism in vivo in Huntington's disease using localized 1H NMR spectroscopy , 1993, Neurology.

[53]  Manish S. Shah,et al.  A novel gene containing a trinucleotide repeat that is expanded and unstable on Huntington's disease chromosomes , 1993, Cell.

[54]  E. Cragoe,et al.  Amiloride and its analogs as tools in the study of ion transport , 1988, The Journal of Membrane Biology.

[55]  J. Edwardson,et al.  Synthesis, properties and biological activity of tritiated N‐benzylamidino‐3,5‐diamino‐6‐chloro‐pyrazine carboxamide — a new ligand for epithelial sodium channels , 1979, The Journal of pharmacy and pharmacology.

[56]  L. Raymond,et al.  Selective neuronal degeneration in Huntington's disease. , 2006, Current topics in developmental biology.

[57]  G. Sagnella,et al.  The renal epithelial sodium channel: genetic heterogeneity and implications for the treatment of high blood pressure. , 2006, Current pharmaceutical design.

[58]  R. Kopito,et al.  Impairment of the ubiquitin-proteasome system by protein aggregation. , 2001, Science.

[59]  B R Rosen,et al.  Evidence for impairment of energy metabolism in vivo in Huntington's disease using localized 1H NMR spectroscopy. , 1993, Neurology.

[60]  E. Cragoe,et al.  Cation transport probes: the amiloride series. , 1990, Methods in enzymology.

[61]  S. Mukerji,et al.  Lactate release from cultured astrocytes and neurons: A comparison , 1988, Glia.

[62]  J. Jones,et al.  Pyrazine diuretics. II. N-amidino-3-amino-5-substituted 6-halopyrazinecarboxamides. , 1967, Journal of medicinal chemistry.