Hope Center member publications

C9orf72 deficiency promotes microglial-mediated synaptic loss in aging and amyloid accumulation
(2021) Neuron, 109 (14), pp. 2275-2291.e8. Cited 1 time.

Lall, D.^a b , Lorenzini, I.^d , Mota, T.A.^a b , Bell, S.^a b , Mahan, T.E.^e , Ulrich, J.D.^e , Davtyan, H.^f , Rexach, J.E.^g , Muhammad, A.K.M.G.^a b , Shelest, O.^b , Landeros, J.^a b , Vazquez, M.^a b , Kim, J.^d , Ghaffari, L.^d , O’Rourke, J.G.^a b , Geschwind, D.H.^g , Blurton-Jones, M.^f , Holtzman, D.M.^e , Sattler, R.^d , Baloh, R.H.^a b c

^a Center for Neural Science and Medicine, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, United States
^b Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, United States
^c Department of Neurology, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, United States
^d Department of Neurobiology, Barrow Neurological Institute, 350 W. Thomas Road, Phoenix, AZ 85013, United States
^e Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer’s Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110, United States
^f Institute for Memory Impairments and Neurological Disorders, Sue & Bill Gross Stem Cell Research Center, University of California, 3200 Gross Hall, 845 Health Sciences Road, Irvine, Irvine, CA 92697, United States
^g Program in Neurogenetics, Department of Neurology, Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, United States

Abstract
C9orf72 repeat expansions cause inherited amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD) and result in both loss of C9orf72 protein expression and production of potentially toxic RNA and dipeptide repeat proteins. In addition to ALS/FTD, C9orf72 repeat expansions have been reported in a broad array of neurodegenerative syndromes, including Alzheimer’s disease. Here we show that C9orf72 deficiency promotes a change in the homeostatic signature in microglia and a transition to an inflammatory state characterized by an enhanced type I IFN signature. Furthermore, C9orf72-depleted microglia trigger age-dependent neuronal defects, in particular enhanced cortical synaptic pruning, leading to altered learning and memory behaviors in mice. Interestingly, C9orf72-deficient microglia promote enhanced synapse loss and neuronal deficits in a mouse model of amyloid accumulation while paradoxically improving plaque clearance. These findings suggest that altered microglial function due to decreased C9orf72 expression directly contributes to neurodegeneration in repeat expansion carriers independent of gain-of-function toxicities. © 2021 Elsevier Inc.

Author Keywords
Alzheimer’s disease;  amyotrophic lateral sclerosis;  C9orf72;  frontotemporal dementia;  microglia;  neurodegeneration

Funding details
AG047644, NS090934
National Institutes of HealthNIHNS097545
Howard Hughes Medical InstituteHHMI
ALS AssociationALSA
Genentech
Merck
Muscular Dystrophy AssociationMDA
JPB FoundationRO1NS085207
University of WashingtonUW
Barrow Neurological FoundationBNF
Rainwater Charitable FoundationRCF5R25 NS065723, AG055524, AG061895

Document Type: Article
Publication Stage: Final
Source: Scopus

Neuronal VCP loss of function recapitulates FTLD-TDP pathology
(2021) Cell Reports, 36 (3), art. no. 109399, . 

Wani, A.^a , Zhu, J.^a , Ulrich, J.D.^a , Eteleeb, A.^b , Sauerbeck, A.D.^a , Reitz, S.J.^a , Arhzaouy, K.^a , Ikenaga, C.^a , Yuede, C.M.^a b , Pittman, S.K.^a , Wang, F.^c , Li, S.^c , Benitez, B.A.^b , Cruchaga, C.^b , Kummer, T.T.^a , Harari, O.^b , Chou, T.-F.^c , Schröder, R.^d , Clemen, C.S.^e f , Weihl, C.C.^a

^a Department of Neurology, Hope Center for Neurological Diseases, Washington University School of Medicine, St. Louis, MO, United States
^b Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States
^c Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States
^d Institute of Neuropathology, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
^e Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
^f Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Cologne, Cologne, Germany

Abstract
The pathogenic mechanism by which dominant mutations in VCP cause multisystem proteinopathy (MSP), a rare neurodegenerative disease that presents as fronto-temporal lobar degeneration with TDP-43 inclusions (FTLD-TDP), remains unclear. To explore this, we inactivate VCP in murine postnatal forebrain neurons (VCP conditional knockout [cKO]). VCP cKO mice have cortical brain atrophy, neuronal loss, autophago-lysosomal dysfunction, and TDP-43 inclusions resembling FTLD-TDP pathology. Conditional expression of a single disease-associated mutation, VCP-R155C, in a VCP null background similarly recapitulates features of VCP inactivation and FTLD-TDP, suggesting that this MSP mutation is hypomorphic. Comparison of transcriptomic and proteomic datasets from genetically defined patients with FTLD-TDP reveal that progranulin deficiency and VCP insufficiency result in similar profiles. These data identify a loss of VCP-dependent functions as a mediator of FTLD-TDP and reveal an unexpected biochemical similarity with progranulin deficiency. © 2021 The Author(s)

Author Keywords
autophagy;  FTD;  FTLD;  multisystem proteinopathy;  neurodegeneration;  progranulin;  TDP-43;  VCP

Funding details
National Institutes of HealthNIHI01BX005204, K24AR073317, P01AG003991, P30AG066444, R01AG031867, R01AG044546, R01AG057777, R01NS102279, R01NS118146, RF1AG053303, RF1AG058501, U01AG058922

Document Type: Article
Publication Stage: Final
Source: Scopus

Reducing Auditory Nerve Excitability by Acute Antagonism of Ca2+-Permeable AMPA Receptors
(2021) Frontiers in Synaptic Neuroscience, 13, art. no. 680621, . 

Walia, A.^a , Lee, C.^a d , Hartsock, J.^a , Goodman, S.S.^b , Dolle, R.^c , Salt, A.N.^a , Lichtenhan, J.T.^a , Rutherford, M.A.^a

^a Department of Otolaryngology, Washington University in St. Louis School of Medicine, St. Louis, MO, United States
^b Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, United States
^c Department of Biochemistry and Molecular Biophysics, Washington University, Center for Drug Discovery, Washington University in St. Louis School of Medicine, St. Louis, MO, United States
^d ‡Choongheon Lee, Department of Otolaryngology, University of Rochester, New York, NY, United States

Abstract
Hearing depends on glutamatergic synaptic transmission mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). AMPARs are tetramers, where inclusion of the GluA2 subunit reduces overall channel conductance and Ca2+ permeability. Cochlear afferent synapses between inner hair cells (IHCs) and auditory nerve fibers (ANFs) contain the AMPAR subunits GluA2, 3, and 4. However, the tetrameric complement of cochlear AMPAR subunits is not known. It was recently shown in mice that chronic intracochlear delivery of IEM-1460, an antagonist selective for GluA2-lacking AMPARs [also known as Ca2+-permeable AMPARs (CP-AMPARs)], before, during, and after acoustic overexposure prevented both the trauma to ANF synapses and the ensuing reduction of cochlear nerve activity in response to sound. Surprisingly, baseline measurements of cochlear function before exposure were unaffected by chronic intracochlear delivery of IEM-1460. This suggested that cochlear afferent synapses contain GluA2-lacking CP-AMPARs alongside GluA2-containing Ca2+-impermeable AMPA receptors (CI-AMPARs), and that the former can be antagonized for protection while the latter remain conductive. Here, we investigated hearing function in the guinea pig during acute local or systemic delivery of CP-AMPAR antagonists. Acute intracochlear delivery of IEM-1460 or systemic delivery of IEM-1460 or IEM-1925 reduced the amplitude of the ANF compound action potential (CAP) significantly, for all tone levels and frequencies, by > 50% without affecting CAP thresholds or distortion product otoacoustic emissions (DPOAE). Following systemic dosing, IEM-1460 levels in cochlear perilymph were ~ 30% of blood levels, on average, consistent with pharmacokinetic properties predicting permeation of the compounds into the brain and ear. Both compounds were metabolically stable with half-lives >5 h in vitro, and elimination half-lives in vivo of 118 min (IEM-1460) and 68 min (IEM-1925). Heart rate monitoring and off-target binding assays suggest an enhanced safety profile for IEM-1925 over IEM-1460. Compound potency on CAP reduction (IC50 ~ 73 μM IEM-1460) was consistent with a mixture of GluA2-lacking and GluA2-containing AMPARs. These data strongly imply that cochlear afferent synapses of the guinea pig contain GluA2-lacking CP-AMPARs. We propose these CP-AMPARs may be acutely antagonized with systemic dosing, to protect from glutamate excitotoxicity, while transmission at GluA2-containing AMPARs persists to mediate hearing during the protection. © Copyright © 2021 Walia, Lee, Hartsock, Goodman, Dolle, Salt, Lichtenhan and Rutherford.

Author Keywords
auditory nerve fiber;  blood labyrinth barrier;  Ca2+-permeable AMPA receptor;  cochlear synapse;  hearing protection;  IEM-1460 and IEM-1925;  intracochlear drug;  non-competitive open-channel block

Funding details
1071
National Institutes of HealthNIH
National Institute on Deafness and Other Communication DisordersNIDCDR01DC014712, R01DC014997, T32DC000022
National Center for Advancing Translational SciencesNCATSUL1TR002345
University of WashingtonUW
Institute of Clinical and Translational SciencesICTS

Document Type: Article
Publication Stage: Final
Source: Scopus

Intrasubunit and intersubunit steroid binding sites independently and additively mediate a1b2c2L GABAA receptor potentiation by the endogenous neurosteroid allopregnanolone
(2021) Molecular Pharmacology, 100 (1), pp. 19-31. 

Germann, A.L.^a , Pierce, S.R.^a , Tateiwa, H.^a , Sugasawa, Y.^d , Reichert, D.E.^b c , Evers, A.S.^a c , Steinbach, J.H.^a c , Akk, G.^a c

^a Department of Anesthesiology, Washington University, School of Medicine, St. Louis, MO, United States
^b Department of Radiology, Washington University, School of Medicine, St. Louis, MO, United States
^c The Taylor Family Institute for Innovative Psychiatric Research, Washington University, School of Medicine, St. Louis, MO, United States
^d Department of Anesthesiology and Pain Medicine, Juntendo University, School of Medicine, Tokyo, Japan

Abstract
Prior work employing functional analysis, photolabeling, and X-ray crystallography have identified three distinct binding sites for potentiating steroids in the heteromeric GABAA receptor. The sites are located in the membrane-spanning domains of the receptor at the b-a subunit interface (site I) and within the a (site II) and b subunits (site III). Here, we have investigated the effects of mutations to these sites on potentiation of the rat a1b2c2L GABAA receptor by the endogenous neurosteroid allopregnanolone (3a5aP). The mutations were introduced alone or in combination to probe the additivity of effects. We show that the effects of amino acid substitutions in sites I and II are energetically additive, indicating independence of the actions of the two steroid binding sites. In site III, none of the mutations tested reduced potentiation by 3a5aP, nor did a mutation in site III modify the effects of mutations in sites I or II. We infer that the binding sites for 3a5aP act independently. The independence of steroid action at each site is supported by photolabeling data showing that mutations in either site I or site II selectively change steroid orientation in the mutated site without affecting labeling at the unmutated site. The findings are discussed in the context of linking energetic additivity to empirical changes in receptor function and ligand binding. SIGNIFICANCE STATEMENT Prior work has identified three distinct binding sites for potentiating steroids in the heteromeric c-aminobutyric acid type A receptor. This study shows that the sites act independently and additively in the presence of the steroid allopregnanolone and provide estimates of energetic contributions made by steroid binding to each site. Copyright © 2021 by The American Society for Pharmacology and Experimental Therapeutics

Funding details
National Institute of General Medical SciencesNIGMSR01GM108580, R01GM108799
Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine in St. Louis

Document Type: Article
Publication Stage: Final
Source: Scopus

Prescription and acceptance of durable medical equipment in FORTITUDE-ALS, a study of reldesemtiv in ALS: post hoc analyses of a randomized, double-blind, placebo-controlled clinical trial
(2021) Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, . 

Rudnicki, S.A.^a , Andrews, J.A.^b , Genge, A.^c , Jackson, C.^d , Lechtzin, N.^e , Miller, T.M.^f , Cockroft, B.M.^a , Malik, F.I.^a , Meng, L.^a , Wei, J.^a , Wolff, A.A.^a , Shefner, J.M.^g , ON BEHALF OF THE FORTITUDE-ALS STUDY GROUP^h

^a Cytokinetics, Incorporated, South San Francisco, CA, United States
^b The Neurological Institute, Columbia University, New York, NY, United States
^c Montreal Neurological Institute, Montreal, QC, Canada
^d Departments of Neurology and Otolaryngology, University of Texas Health Science Center, San Antonio, TX, United States
^e Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, United States
^f Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States
^g Department of Neurology, Barrow Neurological Institute, Phoenix, AZ, United States

Abstract
Objective: To evaluate the possible effect of reldesemtiv, a fast skeletal muscle troponin activator, on prescription and acceptance of durable medical equipment (DME) in the FORTITUDE-ALS trial. Methods: Health economic outcome information was collected in FORTITUDE-ALS (NCT03160898); sites recorded if and when DME, specifically manual or power wheelchairs, gastrostomy tubes, noninvasive ventilators, or augmentative language devices, was prescribed by a physician and accepted by the patient (DME-PAP) during the trial. Acceptance was defined as the patient agreeing the item was needed. Cox regression analysis compared time to DME-PAP for each reldesemtiv dose with placebo. Post hoc analyses evaluated all reldesemtiv doses compared with placebo. Results: At least one DME item was prescribed and accepted by 33/114 (28.9%) of placebo patients, 19/112 (17.0%) of patients receiving reldesemtiv 150 mg bid, 24/113 (21.2%) receiving 300 mg bid, and 29/117 (24.8%) receiving 450 mg bid. The proportion of new DME-PAP was significantly lower in patients receiving reldesemtiv 150 mg bid vs placebo (17.0% vs 28.9%, p = 0.032). The hazard ratio versus placebo for accepting at least one DME item for all reldesemtiv doses combined was 0.61 (confidence interval: 0.39, 0.96, p = 0.032). 25% of placebo patients were prescribed and agreed to obtain a DME item by 84 days; this threshold was met for reldesemtiv-treated patients at 120 days. Conclusions: Results suggest ALS patients receiving reldesemtiv may have lower risk of and delayed need for DME related to impaired mobility, breathing, swallowing, or speaking; this delay is consistent with other measures indicating delay in disease progression. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Author Keywords
clinical trial;  Disease burden;  FORTITUDE-ALS;  health outcomes research;  reldesemtiv

Funding details
CytokineticsCYTK

Document Type: Article
Publication Stage: Article in Press
Source: Scopus