2007 — 2008 |
Mcbride, Jodi L. |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Non-Alledle Specific Rnai as a Potential Therapy For Huntington's Disease
[unreadable] DESCRIPTION (provided by applicant): Huntington's disease (HD) is an autosomal dominantly-inherited, neurodegenerative disorder caused by an expanded trinucleotide repeat (CAG) at the IT15 locus on chromosome 4. These repeats cause degeneration of striatal and cortical neurons in the brain resulting in a devastating cognitive, psychiatric, and motor disorder. RNA interference (RNAi) has emerged as a tool to decrease diseased gene expression. RNAi therapy involves the delivery of short hairpin RNAs (shRNAs) to affected cells which bind to and decrease the expression of target mRNA. It is a therapy extremely well-suited for diseases such as HD, which arise exclusively from a single, inherited gene mutation. To date, allele-specific silencing of mutant huntingtin (htt) remains unsuccessful because no RNAi-targetable polymorphism representing a large fraction of HD patients has been identified. Therefore, partial reduction of both the normal and the diseased allele should be tested as a therapy for HD. Preliminary studies in our lab demonstrate that short-term (4 months post-injection) adeno-associated viral delivery of three different shRNAs to the striata of CAG 140 mice results in an equal 50% partial reduction of htt. While all three hairpins were efficacious in partially reducing htt, two of the three hairpins induced striatal toxicity while the third did not. Toxicity was evidenced histologically as striatal atrophy and ventricular enlargement seen on Nissl and DARPP-32 stained tissue along with a robust increase in astrogliosis and a microglial response. The aims of this proposal are two- fold: 1) To address the question of why two of the three hairpins caused striatal toxicity even though they were designed using the same set of rules and were injected into the mouse striata at the same volume and titer. I hypothesize that, based on preliminary in vitro data, inappropriate strand biasing (loading both the sense and antisense strands of the hairpin) also occurs, in vivo, following viral delivery of the two toxic hairpins (sh2.4 and sh30.1), while only the correct antisense strand is loaded following viral delivery of the non-toxic hairpin (sh8.2); 2) To perform a long-term study using the non-toxic hairpin assessing the efficacy of partially reducing the expression of both htt alleles in the CAG 140 knock-in mouse as an extension of our preliminary data. Thorough behavioral, histological, molecular, and biochemical analysis will reveal whether a partial reduction of both alleles remains efficacious 10 months post-injection. Together, these two studies will address the molecular mechanisms behind differential cellular responses to viral injection of hairpins into the striatum and whether our non-toxic candidate hairpin is efficacious in the long-term, both of which are critical in developing RNAi as a therapy for HD, and more broadly, assessing RNAi in the mammalian brain. [unreadable] [unreadable] [unreadable]
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0.958 |
2010 — 2011 |
Mcbride, Jodi L. |
K99Activity Code Description: To support the initial phase of a Career/Research Transition award program that provides 1-2 years of mentored support for highly motivated, advanced postdoctoral research scientists. R00Activity Code Description: To support the second phase of a Career/Research Transition award program that provides 1 -3 years of independent research support (R00) contingent on securing an independent research position. Award recipients will be expected to compete successfully for independent R01 support from the NIH during the R00 research transition award period. |
Rnai Therapy For Huntingtons Disease: Safety &Efficacy in the Nonhuman Primate @ Oregon Health &Science University
DESCRIPTION (provided by applicant): Huntington's disease (HD) is a fatal, neurodegenerative disorder resulting from an expanded tri-nucleotide repeat (CAG) in exon 1 of the HD gene (HTT). The glutamine expansion in the encoded protein, huntingtin (HTT) confers a toxic gain of function, causing degeneration of neurons in many brain regions, particularly in the striatum. Because these brain regions are involved with various aspects of motor programming and cognition, HD patients experience many symptoms including chorea (involuntary dance-like movements of the limbs and neck), loss of short-term memory and emotional disturbances that can include anxiety, depression and aggression. RNA interference (RNAi) has recently emerged as a leading candidate approach to reduce expression of disease genes by degrading the encoding mRNA. While normal huntingtin plays a vital role in development, we have demonstrated that a partial (60%) non-allele specific reduction in HTT expression is both well tolerated and therapeutically beneficial in adult HD transgenic mice. Here, we propose to test the efficiency, safety and therapeutic benefit of this approach in the nonhuman primate (NHP) as a pre-clinical step towards developing RNAi as a therapy for HD patients. We first aim to characterize the efficiency and safety of non-allele specific RNAi targeting HTT mRNA in the normal NHP brain as a proof-of-principle. Rhesus macaques (n=4) will receive unilateral, stereotaxic injections into the striatum of a recombinant viral vector that expresses mi2.4 (rAAV-mi2.4), a HTT-specific microRNA. The opposite hemisphere will be injected with a control miRNA (rAAV-miMIS) that does not reduce HTT expression. Animals will undergo behavioral evaluation to assess the efficacy and tolerability of this approach. Three months post-injection, animals will be euthanized and brains will be examined for silencing efficiency and several different safety profiles. Next, we aim to establish a NHP model of HD that includes motor dysfunction, cognitive deficits and emotional manifestations. Rhesus monkeys will receive injections into the striatum of a virus expressing a fragment of mutant HTT (mHTT) with 82 CAG repeats (rAAV-mHTT82Q, n=4) or a control fragment of mHTT with only 18 repeats (rAAV-mHTT-18Q, n=4). This strategy has been previously utilized to create a successful rodent model of HD. Animals will evaluated monthly on a variety of motor, cognitive and psychological assays. Six months post- injection, animals will be euthanized and their brains will be analyzed for signs of HD pathology. Lastly, we aim to test the therapeutic benefit of RNAi in the NHP model of HD. NHPs will be co-injected into the striatum with rAAV-mi2.4 (n=4) or rAAV-miMIS (n=4) along with rAAV-mHTT82Q. Animals will be evaluated monthly on a variety of motor, cognitive and psychological assays. Upon sacrifice at 6 months post-injection, brains will be analyzed for the prevention of HD-related pathology. Together, these studies will assess the safety and therapeutic benefit of RNAi in the NHP brain. The studies proposed here, along with the didactic and applied training, will be invaluable in assisting my transition from a post-doctoral fellow to an independent investigator. PUBLIC HEALTH RELEVANCE: The proposed set of studies aims at testing the benefit of RNA interference as a potential therapy for Huntington's disease (HD). There is no cure for this devastating, fatal disease and currently 30,000 people are affected in the United States alone. Testing the utility of RNA interference in a nonhuman primate model of HD is a necessary and key step towards its potential use in the clinic.
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0.958 |
2011 |
Mcbride, Jodi L. |
P51Activity Code Description: To support centers which include a multidisciplinary and multi-categorical core research program using primate animals and to maintain a large and varied primate colony which is available to affiliated, collaborative, and visiting investigators for basic and applied biomedical research and training. |
Rnai Therapy For Huntingtons Disease: Safey &Efficacy in the Nonhuman Primate @ Oregon Health &Science University
This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. These studies are investigating the safety of suppressing expression of the gene that causes Huntington's disease in the normal rhesus macaque putamen as well as the therapeutic efficacy of decreasing the expression of this gene in a rhesus model of Huntington's disease. To date, we have shown efficacy of reducing HTT expression in the rhesus macaque putamen by 45%. This suppression of HTT is not associated with the manifestation of any behavioral abnormalities nor neuropathological changes in the putamen.
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0.958 |
2011 |
Mcbride, Jodi L. |
P51Activity Code Description: To support centers which include a multidisciplinary and multi-categorical core research program using primate animals and to maintain a large and varied primate colony which is available to affiliated, collaborative, and visiting investigators for basic and applied biomedical research and training. |
Systemic Delivery Rna Interference Using Aav9; Treat Huntington's Disease @ Oregon Health &Science University
This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This project investigates the systemic delivery of viral vectors that express microRNAs targeting the gene that causes Huntington's disease. To date, we have successfully seen viral transduction of both neurons and glia in numerous brain regions following a single, systemic injection of the virus into the jugular vein of mice. Transduced areas of interest include cortex, striatum, globus pallidus, thalamus, hypothalamus, dentate gyrus and hippocampus.
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0.958 |
2012 — 2013 |
Mcbride, Jodi L. |
R00Activity Code Description: To support the second phase of a Career/Research Transition award program that provides 1 -3 years of independent research support (R00) contingent on securing an independent research position. Award recipients will be expected to compete successfully for independent R01 support from the NIH during the R00 research transition award period. |
Rnai Therapy For Huntingtons Disease: Safety & Efficacy in the Nonhuman Primate @ Oregon Health & Science University
Project Summary/Abstract Huntington's disease (HD) is a fatal, neurodegenerative disorder resulting from an expanded tri-nucleotide repeat (CAG) in exon 1 of the HD gene (HTT). The glutamine expansion in the encoded protein, huntingtin (HTT) confers a toxic gain of function, causing degeneration of neurons in many brain regions, particularly in the striatum. Because these brain regions are involved with various aspects of motor programming and cognition, HD patients experience many symptoms including chorea (involuntary dance-like movements of the limbs and neck), loss of short-term memory and emotional disturbances that can include anxiety, depression and aggression. RNA interference (RNAi) has recently emerged as a leading candidate approach to reduce expression of disease genes by degrading the encoding mRNA. While normal huntingtin plays a vital role in development, we have demonstrated that a partial (60%) non-allele specific reduction in HTT expression is both well tolerated and therapeutically beneficial in adult HD transgenic mice. Here, we propose to test the efficiency, safety and therapeutic benefit of this approach in the nonhuman primate (NHP) as a pre-clinical step towards developing RNAi as a therapy for HD patients. We first aim to characterize the efficiency and safety of non-allele specific RNAi targeting HTT mRNA in the normal NHP brain as a proof-of-principle. Rhesus macaques (n=4) will receive unilateral, stereotaxic injections into the striatum of a recombinant viral vector that expresses mi2.4 (rAAV-mi2.4), a HTT-specific microRNA. The opposite hemisphere will be injected with a control miRNA (rAAV-miMIS) that does not reduce HTT expression. Animals will undergo behavioral evaluation to assess the efficacy and tolerability of this approach. Three months post-injection, animals will be euthanized and brains will be examined for silencing efficiency and several different safety profiles. Next, we aim to establish a NHP model of HD that includes motor dysfunction, cognitive deficits and emotional manifestations. Rhesus monkeys will receive injections into the striatum of a virus expressing a fragment of mutant HTT (mHTT) with 82 CAG repeats (rAAV-mHTT82Q, n=4) or a control fragment of mHTT with only 18 repeats (rAAV-mHTT-18Q, n=4). This strategy has been previously utilized to create a successful rodent model of HD. Animals will evaluated monthly on a variety of motor, cognitive and psychological assays. Six months post- injection, animals will be euthanized and their brains will be analyzed for signs of HD pathology. Lastly, we aim to test the therapeutic benefit of RNAi in the NHP model of HD. NHPs will be co-injected into the striatum with rAAV-mi2.4 (n=4) or rAAV-miMIS (n=4) along with rAAV-mHTT82Q. Animals will be evaluated monthly on a variety of motor, cognitive and psychological assays. Upon sacrifice at 6 months post-injection, brains will be analyzed for the prevention of HD-related pathology. Together, these studies will assess the safety and therapeutic benefit of RNAi in the NHP brain. The studies proposed here, along with the didactic and applied training, will be invaluable in assisting my transition from a post-doctoral fellow to an independent investigator.
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0.958 |
2016 — 2020 |
Mcbride, Jodi L. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Cortico-Basal Ganglia Connectivity in a Non-Human Primate Model of Huntington's Disease @ Oregon Health & Science University
PROJECT SUMMARY The goal of the proposed research in this application is to characterize alterations in cortico-basal ganglia connectivity in a novel non-human primate model of Huntington's disease (HD) recently developed in my laboratory. Previous K99/R00 funding (2010-2015) from the NINDS supported the development of this new model, wherein we found that AAV-mediated expression of mutant HTT in the caudate and putamen of rhesus macaques lead to a wide array of behavioral manifestations of disease including the progressive development of both motor and cognitive phenotypes also seen in human HD patients. Brains from HD NHPs showed DARPP-32 loss, inclusion formation and gliosis, along with reduced levels of key striatal transcripts, including reduced glutamate and dopamine receptor levels (manuscript in preparation). In addition to striatal pathology, we found mHTT expression, inclusion bodies and gliosis in numerous cortical areas (frontal and motor) and regions throughout the basal ganglia (globus pallidus, substantia nigra), likely owing to transport of the AAV vector. These findings strongly suggest that basal ganglia connectivity may be disrupted in our NHP HD model. The objective of this current proposal is to characterize cortico-basal ganglia connectivity in the brains of our HD NHPs using resting state fMRI and diffusion tensor imaging to assess functional connectivity and white matter integrity, respectively (Aim 1). Additionally, we will evaluate glutamate and dopamine neurotransmission in the caudate and putamen using electrophysiological analyses (Aim 2). We will test our central hypothesis that there is a progressive decline in basal ganglia connectivity in our HD NHP brains that correlates with 1) the longitudinal development of cognitive and motor phenotypes, 2) reduced glutamate and dopamine transmission in cortico-striatal and nigro-striatal connections with medium spiny neurons in the caudate and putamen and 3) neuropathology including inclusion formation, gliosis and neuronal dysfunction. I have assembled an excellent team of scientists to accomplish these goals with cumulative expertise in resting state fMRI analysis of cortico-striatal functional connectivity (Dr. Christopher Kroenke), electrophysiological recordings of medium spiny neurons in the rhesus macaque striatum (Dr. Verginia Cuzon Carlson), statistical analysis of complex datasets (Dr. Byung Park), as well as my background and expertise in HD neurobiology, AAV-mediated gene transfer, NHP MRI-guided neurosurgery, complex NHP motor and cognitive behavioral assessment and the use of molecular and histological techniques to assess HD neuropathology. By the end of the studies proposed here, we will have characterized alterations in basal ganglia connectivity in a novel AAV- mHTT mediated monkey model of HD, elucidating potential pathophysiological mechanisms that underlie motor and cognitive decline. Additionally, the data obtained from these studies will provide the unique opportunity to identify imaging, behavioral, electrophysiological and neuropathological endpoints that will be used for future therapeutic studies using this model.
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0.958 |
2016 |
Mcbride, Jodi L. |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Global Rna Interference Therapy For Huntingtons Disease @ Oregon Health & Science University
Project summary/Abstract Huntington's disease (HD) is a dominantly-inherited genetic disorder caused by a mutation in the HTT gene (HTT) that leads to widespread degeneration in many regions of the brain and a devastating array of symptoms that include a hyperkinetic movement disorder, gait disturbance, cognitive decline, psychiatric symptoms and metabolic dysfunction. Unfortunately, there is currently no therapy for HD and it always results in death. However, the emergence of RNA interference (RNAi) as a tool to reduce gene expression has made it possible for our lab and others to develop adeno-associated viral vectors expressing RNAi silencing constructs that target mHTT (AAV-RNAi). We have shown that focal injections of AAV-RNAi into the striatum or the hypothalamus prevent motor and metabolic deficits, respectively, in mouse models of HD. Similarly, my laboratory is currently conducting pre-clinical dosing, biodistribution and safety studies by injecting RNAi constructs in the striatum of rhesus macaques as a prelude to a potential Phase 1 clinical trial. The striatum will be the target of our first AAV-RNAi clinical trial because it is heavily affected in HD, it is a large surgical target and there are clear and robust clinical motor readouts. However, to be clear, the striatum is only one of numerous brain regions affected by the disease. Thus, it is essential that future therapies reduce mHTT expression throughout the entire CNS to provide maximal benefit to the patient. Consequently, the long-term goal of this proposal is to develop a global delivery strategy that effectively reduces mHTT expression in several affected brain regions in HD. This strategy will have a much larger impact on the quality of life of the HD patient. The objective here is to evaluate AAV-PHP.B, a novel AAV9 capsid mutant, as a gene therapy tool to deliver an RNAi construct (mi2.4) to target brain regions affected in HD. Both serotypes will be evaluated using 2 different delivery routes: intra-carotid artery or intra-cisterna magna. The major goals of this proposal are 1) to prepare and characterize AAV-PHP.B-mi2.4, AAV9-mi2.4 and control vectors, 2) to perform pharmacokinetic and biodistribution superiority studies of AAV-PHP.B-mi2.4 and AAV9-mi2.4 in N171-82Q transgenic HD mice to define a dose and delivery route that leads to a significant 40% reduction of mHTT in the cortex and striatum and 3) to perform in vivo efficacy and tolerability studies in 2 different HD mouse models (N171-82Q and BACHD) to establish the minimum effective dose of our lead construct that significantly ameliorates behavioral, neurophysiological and neuropathological deficits germane to each model. These proposed experiments are both significant and innovative because they represent the first steps towards a systemic strategy to attenuate the wide array of devastating symptoms that plague Huntington's patients.
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0.958 |