Nicholas Boulis

Emory University, Atlanta, Georgia, United States

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Publications (35)134.45 Total impact

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    ABSTRACT: After injection into muscle and peripheral nerves, a variety of viral vectors undergo retrograde transport to lower motor neurons. However, because of its attractive safety profile and durable gene expression, adeno-associated virus (AAV) remains the only vector to have been applied to the human nervous system for the treatment of neurodegenerative disease. Nonetheless, only a very small fraction of intramuscularly injected AAV vector arrives at the spinal cord. To engineer a novel AAV vector by inserting a neuronal targeting peptide (Tet1), with binding properties similar to those of tetanus toxin, into the AAV1 capsid. Integral to this approach was the use of structure-based design to increase the effectiveness of functional capsid engineering. This approach allowed the optimization of scaffolding regions for effective display of the foreign epitope while minimizing disruption of the native capsid structure. We also validated an approach by which low-titer tropism-modified AAV vectors can be rescued by particle mosaicism with unmodified capsid proteins. Importantly, our rationally engineered AAV1-based vectors exhibited markedly enhanced transduction of cultured motor neurons, diminished transduction of nontarget cells, and markedly superior retrograde delivery compared with unmodified AAV1 vector. This approach promises a significant advancement in the rational engineering of AAV vectors for diseases of the nervous system and other organs. AAV, adeno-associated virusALS, amyotrophic lateral sclerosisDMEM, Dulbecco-modified Eagle mediumDRG, dorsal root gangliaDRP, DNase-resistant particleMOI, multiplicity of infectionPBS, phosphate-buffered salinePCR, polymerase chain reactionrAAV, recombinant adeno-associated virus.
    Neurosurgery 12/2014; · 3.03 Impact Factor
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    ABSTRACT: Objective The first US Food and Drug Administration–approved clinical trial to treat amyotrophic lateral sclerosis (ALS) with neural stem cell–based therapy is in progress. The goal of the current study was to identify and assess the survival of human spinal cord–derived neural stem cells (HSSCs) transplanted into the spinal cord in patients with ALS.Methods Spinal cords transplanted with HSSCs were examined from six autopsy cases. Homogenized tissues were interrogated for the presence of donor versus recipient DNA using real-time PCR methods (qPCR). Fluorescence in situ hybridization (FISH) was performed using DNA probes for XY chromosomes to identify male donor HSSCs in one female case, and immunohistochemistry (IHC) was used to characterize the identified donor cells.ResultsGenomic DNA from donor HSSCs was identified in all cases, comprising 0.67–5.4% of total tissue DNA in patients surviving 196 to 921 days after transplantation. In the one female patient a “nest” of cells identified on H&E staining were XY-positive by FISH, confirming donor origin. A subset of XY-positive cells labeled for the neuronal marker NeuN and stem cell marker SOX2.InterpretationThis is the first study to identify human neural stem cells transplanted into a human spinal cord. Transplanted HSSCs survived up to 2.5 years posttransplant. Some cells differentiated into neurons, while others maintained their stem cell phenotype. This work is a proof of concept of the survival and differentiation of human stems cell transplanted into the spinal cord of ALS patients.
    Annals of Clinical and Translational Neurology. 10/2014;
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    ABSTRACT: Diseases of the nervous system have devastating effects and are widely distributed among the population, being especially prevalent in the elderly. These diseases are often caused by inherited genetic mutations that result in abnormal nervous system development, neurodegeneration, or impaired neuronal function. Other causes of neurological diseases include genetic and epigenetic changes induced by environmental insults, injury, disease-related events or inflammatory processes. Standard medical and surgical practice has not proved effective in curing or treating these diseases, and appropriate pharmaceuticals do not exist or are insufficient to slow disease progression. Gene therapy is emerging as a powerful approach with potential to treat and even cure some of the most common diseases of the nervous system. Gene therapy for neurological diseases has been made possible through progress in understanding the underlying disease mechanisms, particularly those involving sensory neurons, and also by improvement of gene vector design, therapeutic gene selection, and methods of delivery. Progress in the field has renewed our optimism for gene therapy as a treatment modality that can be used by neurologists, ophthalmologists and neurosurgeons. In this Review, we describe the promising gene therapy strategies that have the potential to treat patients with neurological diseases and discuss prospects for future development of gene therapy.
    Nature Reviews Neurology 04/2013; · 15.52 Impact Factor
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    ABSTRACT: OBJECTIVE: In an effort to account for deficiencies in axonal transport that limit the effectiveness of neurotrophic factors, this study tested the safety and feasibility, in moderately advanced Parkinson disease (PD), of bilaterally administering the gene therapy vector AAV2-neurturin (CERE-120) to the putamen plus substantia nigra (SN, a relatively small structure deep within the midbrain, in proximity to critical neuronal and vascular structures). METHODS: After planning and minimizing risks of stereotactically targeting the SN, an open-label, dose-escalation safety trial was initiated in 6 subjects with PD who received bilateral stereotactic injections of CERE-120 into the SN and putamen. RESULTS: Two-year safety data for all subjects suggest the procedures were well-tolerated, with no serious adverse events. All adverse events and complications were expected for patients with PD undergoing stereotactic brain surgery. CONCLUSIONS: Bilateral stereotactic administration of CERE-120 to the SN plus putamen in PD is feasible and this evaluation provides initial empirical support that it is safe and well-tolerated. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that bilateral neurturin gene delivery (CERE-120) to the SN plus putamen in patients with moderately advanced PD is feasible and safe.
    Neurology 04/2013; 80:1698-1701. · 8.30 Impact Factor
  • Jonathan Riley, Carl V Hurtig, Nicholas Boulis
    Personalized Medicine 08/2012; 9(6):645-655. · 1.13 Impact Factor
  • Jonathan Riley, Jason Lamanna, Nicholas Boulis
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    ABSTRACT: An abstract is unavailable. This article is available as HTML full text and PDF.
    Contemporary Neurosurgery. 03/2012; 34(6):1–5.
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    ABSTRACT: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease, which is the leading genetic cause of mortality in children. To date no effective treatment exists for SMA. The genetic basis for SMA has been well documented as a mutation in the gene for survival of motor neuron (SMN). Because there is an understanding of which gene needs to be replaced (SMN) and where it needs to be replaced (spinal motor systems), SMA is an ideal target for gene replacement via gene therapy. While a variety of animal models for SMA exist, they are either too fulminant to realistically test most gene delivery strategies, or too mild to provide a robust read out of the therapeutic effect. The field, therefore, requires a robust model with a slower symptomatic progression. A conditional knockout of SMN in neuronal cell types, giving a phenotype of functional motor defects, weight loss and reduced life expectancy partially satisfies this need (Frugier, Tiziano et al. 2000). This Cre/LoxP mediated neuron specific model presents an attractive alternative. In the present manuscript, we characterize the functional motor deficits of the model. We observed a decline in locomotor ability, as assessed by open field testing. The finer functions of motor skills such as righting reflex and grip strength were also observed to degenerate in the SMA mice. The decline in motor function that we observed here correlates with the anatomical decline in motor neurons and motor axons presented in the literature (Ferri, Melki et al. 2004). This work adds to our understanding and knowledge base of this Cre/LoxP model and provides a basis from which functional recovery, following interventions can be assessed.
    Neurobiology of Disease 12/2011; 45(3):992-8. · 5.62 Impact Factor
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    ABSTRACT: Adeno-associated viral vector 9 (AAV9) has recently been shown to penetrate the blood-brain barrier via intravascular administration, making it a good candidate for diffuse gene delivery. However, the potential side effects of systemic delivery are unknown. Intrathecal viral vector administration may be more invasive than intravenous injections, but it requires far less vector and it can be performed on an outpatient basis, making it an ideal route of delivery for clinical translation. A total of 12 domestic farm pigs (<20 kg) underwent a single-level lumbar laminectomy with intrathecal catheter placement for AAV9 delivery. Animals were perfused and the tissue was harvested 30 days after treatment. Gene expression was assessed by anti-green fluorescent protein immunohistochemistry. Although a single lumbar injection resulted in gene expression limited to the lumbar segment of the spinal cord, three consecutive boluses via a temporary catheter resulted in diffuse transduction of motor neurons (MNs) throughout the cervical, thoracic and lumbar spinal cords. We now present the first successful robust transduction of MNs in the spinal cord of a large animal via intrathecal gene delivery using a self-complementary AAV9. These promising results can be translated to many MN diseases requiring diffuse gene delivery.
    Gene therapy 09/2011; 19(8):852-9. · 4.75 Impact Factor
  • Nicholas Boulis, Thais Federici
    Neurosurgery 02/2011; 68(2):E599-600. · 3.03 Impact Factor
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    Chalonda R Handy, Christina Krudy, Nicholas Boulis
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    ABSTRACT: Chronic pain is experienced by as many as 90% of cancer patients at some point during the disease. This pain can be directly cancer related or arise from a sensory neuropathy related to chemotherapy. Major pharmacological agents used to treat cancer pain often lack anatomical specificity and can have off-target effects that create new sources of suffering. These concerns establish a need for improved cancer pain management. Gene therapy is emerging as an exciting prospect. This paper discusses the potential for viral vector-based treatment of cancer pain. It describes studies involving vector delivery of transgenes to laboratory pain models to modulate the nociceptive cascade. It also discusses clinical investigations aimed at regulating pain in cancer patients. Considering the prevalence of pain among cancer patients and the growing potential of gene therapy, these studies could set the stage for a new class of medicines that selectively disrupt nociceptive signaling with limited off-target effects.
    Pain research and treatment. 01/2011; 2011:987597.
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    ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder marked by progressive loss of motor neurons, muscle wasting, and respiratory dysfunction. With disease progression, secondary symptoms arise creating new problematic conditions for ALS patients. Amongst these is pain. Although not a primary consequence of disease, pain occurs in a substantial number of individuals. Yet, studies investigating its pathomechanistic properties in the ALS patient are lacking. Therefore, more exploratory efforts into its scope, severity, impact, and treatment should be initiated. Several studies investigating the use of Clostridial neurotoxins for the reduction of pain in ALS patients suggest the potential for a neural specific approach involving focal drug delivery. Gene therapy represents a way to accomplish this. Therefore, the use of viral vectors to express transgenes that modulate the nociceptive cascade could prove to be an effective way to achieve meaningful benefit in conditions of pain in ALS.
    Neurology research international. 01/2011; 2011:403808.
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    ABSTRACT: In an open-label phase 1 trial, gene delivery of the trophic factor neurturin via an adeno-associated type-2 vector (AAV2) was well tolerated and seemed to improve motor function in patients with advanced Parkinson's disease. We aimed to assess the safety and efficacy of AAV2-neurturin in a double-blind, phase 2 randomised trial. We did a multicentre, double-blind, sham-surgery controlled trial in patients with advanced Parkinson's disease. Patients were randomly assigned (2:1) by a central, computer generated, randomisation code to receive either AAV2-neurturin (5·4 × 10¹¹ vector genomes) injected bilaterally into the putamen or sham surgery. All patients and study personnel with the exception of the neurosurgical team were masked to treatment assignment. The primary endpoint was change from baseline to 12 months in the motor subscore of the unified Parkinson's disease rating scale in the practically-defined off state. All randomly assigned patients who had at least one assessment after baseline were included in the primary analyses. This trial is registered at, NCT00400634. Between December, 2006, and November, 2008, 58 patients from nine sites in the USA participated in the trial. There was no significant difference in the primary endpoint in patients treated with AAV2-neurturin compared with control individuals (difference -0·31 [SE 2·63], 95% CI -5·58 to 4·97; p=0·91). Serious adverse events occurred in 13 of 38 patients treated with AAV2-neurturin and four of 20 control individuals. Three patients in the AAV2-neurturin group and two in the sham surgery group developed tumours. Intraputaminal AAV2-neurturin is not superior to sham surgery when assessed using the UPDRS motor score at 12 months. However, the possibility of a benefit with additional targeting of the substantia nigra and longer term follow-up should be investigated in further studies. Ceregene and Michael J Fox Foundation for Parkinson's Research.
    The Lancet Neurology 10/2010; 9(12):1164-72. · 21.82 Impact Factor
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    ABSTRACT: The purpose of Clinical Problem Solving articles is to present management challenges to give practicing neurosurgeons insight into how field leaders address these dilemmas. This illustration is accompanied by a brief review of the literature on the topic. The case of a 16-year-old boy presenting with headaches is presented. The patient is found to have a typical colloid cyst at the foramen of Monro. Bilateral ventriculoperitoneal shunt placement had been performed as an initial treatment of the patient before presentation. Surgeons experienced in open and endoscopic surgery discuss their individual approaches to colloid cysts, in the context of previous shunting, providing a varied perspective on the clinical challenges posed by these lesions. Both open and endoscopic options remain viable for excision of a colloid cyst. Each has associated potential complications, as illustrated by the current case.
    Neurosurgery 07/2010; 67(1):197-203; discussion 203-4. · 3.03 Impact Factor
  • Parkinsonism & Related Disorders 12/2009; 15. · 4.13 Impact Factor
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    ABSTRACT: Modulation of the nervous system by electrical or chemical means (neuromodulation) is becoming increasingly sophisticated, with application to a growing number of neurological diseases. However, both chemical and electrical neuromodulation are limited in their specificity. Electrical stimulation, for example, indiscriminately activates different neuronal populations within the electrical field, leading to side effects that can limit efficacy. The delivery of genes that encode proteins capable of conveying light sensitivity to neurons has provided a tool that may overcome some of the limitations of traditional neuromodulation techniques. Activation or inhibition of specific neuronal populations with different wavelengths of light opens up possibilities for modulating neural circuits with previously unimagined levels of precision. We briefly review this new technology, illustrating its advantages and potential applications.
    Neurosurgery 06/2009; 64(5):796-804; discussion 804. · 3.03 Impact Factor
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    ABSTRACT: The current lack of a validated intraspinal delivery approach precludes translation of promising cell or viral-based therapeutics for treatment of varied spinal cord afflictions. We have developed a stabilized cervical microinjection platform with the intent of precise delivery to intraspinal sites of interest. Nine 30-40 kg female swine underwent coordinate-based microinjection AAV2-GFP at three injected volumes (10, 25, and 50 microL (n= 3/group)) and matched infusion rates (1.0, 2.5, and 5.0 microL/min) over a period (t= 10 minutes). Preliminary validation is provided by behavioral and targeting data demonstrating safe delivery of a viral vector carrying a fluorescent reporter gene to the cervical spinal cord ventral horn.
    Clinical and Translational Science 04/2009; 2(2):165-7. · 2.33 Impact Factor
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    ABSTRACT: Apoptosis has been shown to play an important role in motor neuron (MN) degeneration in both neurodegenerative disease and peripheral neuropathy. Bcl-xL, an antiapoptotic protein, is down-regulated in these etiologies [corrected] The carboxyl-terminal domain of the tetanus toxin heavy chain (Hc) has high affinity for axon terminal binding and uptake into motor and dorsal root ganglion (DRG) neurons. We report the development of a fusion protein between Hc and Bcl-xL to enhance uptake of Bcl-xL by MNs as a strategy for inhibiting peripheral neuronal apoptosis. The genes for Hc, Bcl-xL, and green fluorescent protein were cloned into an Escherichia coli expression system in 2 different arrangements. Fusion proteins were purified through chromatography. Cultured E15 rat spinal cord MNs and DRG cells were used to demonstrate neuron-specific uptake and retrograde transport of the fusion proteins mediated by Hc. Finally, glutamate-induced apoptosis was used as an in vitro model to measure the antiapoptotic effects of the fusion proteins. Bcl-xL fusion proteins were found to bind specifically and undergo uptake into cultured rat spinal MNs. The fusion proteins were also taken up by DRG axonal terminals and transported back to the cell bodies in Campenot compartmentalized chambers (Tyler Research Corp., Edmonton, Canada). Finally, fusion protein application improved cell survival and decreased apoptosis in glutamate-mediated excitotoxicity of the SH-SY5Y neuronal cells. Hc can be applied as a universal carrier for therapeutic cargo delivery specifically to MNs or DRGs. The fusion proteins between Bcl-xL and Hc constructed in this study might bear applications to the treatment of MN disease, neuropathy, or nerve injury through nerve or intramuscular injection.
    Neurosurgery 01/2009; 63(6):1175-82; discussion 1182-4. · 3.03 Impact Factor
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    Jonathan Riley, Bethwel Raore, Nicholas Boulis
    Clinical neurosurgery 01/2009; 56:9-17.
  • Jonathan Riley, Walter Sweeney, Nicholas Boulis
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    ABSTRACT: Recent advances in the laboratory have improved the current understanding of neurobiological mechanisms underlying the initiating events and pathological progression observed in amyotrophic lateral sclerosis (ALS). Whereas initial studies have revealed the late-stage intracellular cascades contributing to neuronal dysfunction and cell death, more recently collected data have begun to elucidate the presence and importance of a "non-cell autonomous" component indicating that affected glial cell subtypes may serve distinct and required roles. Pharmacological interventions for ALS have largely been disappointing likely in part because they have failed to address either the proximate events contributing to neuronal dysfunction and death or the deleterious contributions of non-neuronal cells within the local microenvironment. Alternatively, cell-based therapeutics offer the potential of a multifaceted approach oriented toward the dual ends of protecting remaining viable neurons and attempting to restore neuronal function lost as a manifestation of disease progression. The authors review the evolving knowledge of disease initiation and progression, with specific emphasis on the role of affected glia as crucial contributors to the observed ALS phenotype. This basis is used to underscore the potential roles of cell-based therapeutics as modifiers of the ALS-specific microenvironment.
    Neurosurgical FOCUS 02/2008; 24(3-4):E10. · 2.14 Impact Factor
  • Neurosurgery 11/2007; 61(4):815-24; discussion 824-5. · 3.03 Impact Factor

Publication Stats

622 Citations
134.45 Total Impact Points


  • 2006–2014
    • Emory University
      • • Department of Pathology and Laboratory Medicine
      • • Department of Neurosurgery
      • • Department of Psychiatry and Behavioral Sciences
      Atlanta, Georgia, United States
  • 2009
    • Stanford University
      • Department of Neurosurgery
      Stanford, CA, United States
  • 2004–2009
    • Cleveland Clinic
      • • Department of Cell Biology
      • • Department of Neurosurgery
      Cleveland, OH, United States
  • 2008
    • Case Western Reserve University School of Medicine
      Cleveland, Ohio, United States
  • 2005
    • Lerner Research Institute
      Cleveland, Ohio, United States
    • The Ohio State University
      Columbus, Ohio, United States
  • 1999–2004
    • University of Michigan
      • • Department of Neurology
      • • Department of Surgery
      Ann Arbor, MI, United States