# Patent

## Title
Intrathecal delivery of recombinant adeno-associated virus 9

## Abstract

The present invention relates to Adeno-associated virus type 9 methods and materials useful for intrathecal delivery of polynucleotides. Use of the methods and materials is indicated, for example, for treatment of lower motor neuron diseases such as SMA and ALS as well as Pompe disease and lysosomal storage disorders. It is disclosed that administration of a non-ionic, low-osmolar contrast agent, together with a rAAV9 vector for the expression of Survival Motor Neuron protein, improves the survival of SMN mutant mice as compared to the administration of the expression vector alone.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Application No. 61/678,458 filed Aug. 1, 2012, which is incorporated by reference in its entirety herein.


STATEMENT OF GOVERNMENT INTEREST
This invention was made with Government support under grant no. NS069476 from the National Institutes of Health. The Government has certain rights in the invention.


INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ELECTRONICALLY
Incorporated by reference in its entirety is a sequence listing in computer-readable form submitted concurrently herewith and identified as follows: ASCII text file named “47099PCT_SeqListing.txt”, 8,954 bytes, created 31 Jul. 2013.
FIELD OF THE INVENTION
The present invention relates to Adeno-associated virus type 9 methods and materials useful for intrathecal delivery (i.e., delivery into the space under the arachnoid membrane of the brain or spinal cord) of polynucleotides. Use of the methods and materials is indicated, for example, for treatment of lower motor neuron diseases such as SMA and ALS as well as Pompe disease and lysosomal storage disorders.
BACKGROUND
Large-molecule drugs do not cross the blood-brain-barrier (BBB) and 98% of small-molecules cannot penetrate this barrier, thereby limiting drug development efforts for many CNS disorders [Pardridge, W. M. Nat Rev Drug Disco 1: 131-139 (2002)]. Gene delivery has recently been proposed as a method to bypass the BBB [Kaspar, et al., Science 301: 839-842 (2003)]; however, widespread delivery to the brain and spinal cord has been challenging. The development of successful gene therapies for motor neuron disease will likely require widespread transduction within the spinal cord and motor cortex. Two of the most common motor neuron diseases are spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), both debilitating disorders of children and adults, respectively, with no effective therapies to date. Recent work in rodent models of SMA and ALS involves gene delivery using viruses that are retrogradely transported following intramuscular injection [Kaspar et al., Science 301: 839-842 (2003); Azzouz et al., J Clin Invest 114: 1726-1731 (2004); Azzouz et al., Nature 429: 413-417 (2004); Ralph et al., Nat Med 11: 429-433 (2005)]. However, clinical development may be difficult given the numerous injections required to target the widespread region of neurodegeneration throughout the spinal cord, brainstem and motor cortex to effectively treat these diseases. AAV vectors have also been used in a number of recent clinical trials for neurological disorders, demonstrating sustained transgene expression, a relatively safe profile, and promising functional responses, yet have required surgical intraparenchymal injections [Kaplitt et al., Lancet 369: 2097-2105 (2007); Marks et al., Lancet Neurol 7: 400-408 (2008); Worgall et al., Hum Gene Ther (2008)].
SMA is an early pediatric neurodegenerative disorder characterized by flaccid paralysis within the first six months of life. In the most severe cases of the disease, paralysis leads to respiratory failure and death usually by two years of age. SMA is the second most common pediatric autosomal recessive disorder behind cystic fibrosis with an incidence of 1 in 6000 live births. SMA is a genetic disorder characterized by the loss of lower motor neurons (LMNs) residing along the length of the entire spinal cord. SMA is caused by a reduction in the expression of the survival motor neuron (SMN) protein that results in denervation of skeletal muscle and significant muscle atrophy. SMN is a ubiquitously expressed protein that functions in U snRNP biogenesis.
In humans there are two very similar copies of the SMN gene termed SMN1 and SMN2. The amino acid sequence encoded by the two genes is identical. However, there is a single, silent nucleotide change in SMN2 in exon 7 that results in exon 7 being excluded in 80-90% of transcripts from SMN2. The resulting truncated protein, called SMNΔ7, is less stable and rapidly degraded. The remaining 10-20% of transcript from SMN2 encodes the full length SMN protein. Disease results when all copies of SMN1 are lost, leaving only SMN2 to generate full length SMN protein. Accordingly, SMN2 acts as a phenotypic modifier in SMA in that patients with a higher SMN2 copy number generally exhibit later onset and less severe disease.
Therapeutic approaches for SMA have mainly focused on developing drugs for increasing SMN levels or enhancing residual SMN function. Despite years of screening, no drugs have been fully effective for increasing SMN levels as a restorative therapy. A number of mouse models have been developed for SMA. See, Hsieh-Li et al., Nature Genetics, 24 (1): 66-70 (2000); Le et al., Hum. Mol. Genet., 14 (6): 845-857 (2005); Monani et al., J. Cell. Biol., 160 (1): 41-52 (2003) and Monani et al., Hum. Mol. Genet., 9 (3): 333-339 (2000). A recent study express a full length SMN cDNA in a mouse model and the authors concluded that expression of SMN in neurons can have a significant impact on symptoms of SMA. See Gavrilina et al., Hum. Mol. Genet., 17(8):1063-1075 (2008).
ALS is another disease that results in loss of muscle and/or muscle function. First characterized by Charcot in 1869, it is a prevalent, adult-onset neurodegenerative disease affecting nearly 5 out of 100,000 individuals. ALS occurs when specific nerve cells in the brain and spinal cord that control voluntary movement gradually degenerate. Within two to five years after clinical onset, the loss of these motor neurons leads to progressive atrophy of skeletal muscles, which results in loss of muscular function resulting in paralysis, speech deficits, and death due to respiratory failure.
The genetic defects that cause or predispose ALS onset are unknown, although missense mutations in the SOD-1 gene occurs in approximately 10% of familial ALS cases, of which up to 20% have mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1), located on chromosome 21. SOD-1 normally functions in the regulation of oxidative stress by conversion of free radical superoxide anions to hydrogen peroxide and molecular oxygen. To date, over 90 mutations have been identified spanning all exons of the SOD-1 gene. Some of these mutations have been used to generate lines of transgenic mice expressing mutant human SOD-1 to model the progressive motor neuron disease and pathogenesis of ALS.
SMA and ALS are two of the most common motor neuron diseases. Recent work in rodent models of SMA and ALS has examined treatment by gene delivery using viruses that are retrogradedly transported following intramuscular injection. See Azzouz et al., J. Clin. Invest., 114: 1726-1731 (2004); Kaspar el al., Science, 301: 839-842 (2003); Azzouz el al., Nature, 429: 413-417 (2004) and Ralph et al., Nature Medicine, 11: 429-433 (2005). Clinical use of such treatments may be difficult given the numerous injections required to target neurodegeneration throughout the spinal cord, brainstem and motor cortex.
Adeno-associated virus (AAV) is a replication-deficient parvovirus, the single-stranded DNA genome of which is about 4.7 kb in length including 145 nucleotide inverted terminal repeat (ITRs). The nucleotide sequence of the AAV serotype 2 (AAV2) genome is presented in Srivastava et al., J Virol, 45: 555-564 (1983) as corrected by Ruffing et al., J Gen Virol, 75: 3385-3392 (1994). Cis-acting sequences directing viral DNA replication (rep), encapsidation/packaging and host cell chromosome integration are contained within the ITRs. Three AAV promoters (named p5, p19, and p40 for their relative map locations) drive the expression of the two AAV internal open reading frames encoding rep and cap genes. The two rep promoters (p5 and p19), coupled with the differential splicing of the single AAV intron (at nucleotides 2107 and 2227), result in the production of four rep proteins (rep 78, rep 68, rep 52, and rep 40) from the rep gene. Rep proteins possess multiple enzymatic properties that are ultimately responsible for replicating the viral genome. The cap gene is expressed from the p40 promoter and it encodes the three capsid proteins VP1, VP2, and VP3. Alternative splicing and non-consensus translational start sites are responsible for the production of the three related capsid proteins. A single consensus polyadenylation site is located at map position 95 of the AAV genome. The life cycle and genetics of AAV are reviewed in Muzyczka, Current Topics in Microbiology and Immunology, 158: 97-129 (1992).
AAV possesses unique features that make it attractive as a vector for delivering foreign DNA to cells, for example, in gene therapy. AAV infection of cells in culture is noncytopathic, and natural infection of humans and other animals is silent and asymptomatic. Moreover, AAV infects many mammalian cells allowing the possibility of targeting many different tissues in vivo. Moreover, AAV transduces slowly dividing and non-dividing cells, and can persist essentially for the lifetime of those cells as a transcriptionally active nuclear episome (extrachromosomal element). The AAV proviral genome is infectious as cloned DNA in plasmids which makes construction of recombinant genomes feasible. Furthermore, because the signals directing AAV replication, genome encapsidation and integration are contained within the ITRs of the AAV genome, some or all of the internal approximately 4.3 kb of the genome (encoding replication and structural capsid proteins, rep-cap) may be replaced with foreign DNA such as a gene cassette containing a promoter, a DNA of interest and a polyadenylation signal. The rep and cap proteins may be provided in trans. Another significant feature of AAV is that it is an extremely stable and hearty virus. It easily withstands the conditions used to inactivate adenovirus (56° to 65° C. for several hours), making cold preservation of AAV less critical. AAV may even be lyophilized. Finally, AAV-infected cells are not resistant to superinfection.
Multiple serotypes of AAV exist and offer varied tissue tropism. Known serotypes include, for example, AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10 and AAV11. AAV9 is described in U.S. Pat. No. 7,198,951 and in Gao et al., J. Virol., 78: 6381-6388 (2004). Advances in the delivery of AAV6 and AAV8 have made possible the transduction by these serotypes of skeletal and cardiac muscle following simple systemic intravenous or intraperitoneal injections. See Pacak et al., Circ. Res., 99(4): 3-9 (1006) and Wang et al., Nature Biotech., 23(3): 321-8 (2005). The use of AAV to target cell types within the central nervous system, though, has required surgical intraparenchymal injection. See, Kaplitt et al., supra; Marks et al., supra and Worgall et al., supra.
There thus remains a need in the art for methods and vectors for delivering polynucleotides to the central nervous system.
SUMMARY
The present invention provides methods and materials useful for intrathecal delivery of polynucleotides to the central nervous system using recombinant a recombinant AAV9 (rAAV9) as a vector.
More specifically, the invention provides methods of delivering a polynucleotide to the central nervous system of a patient in need thereof comprising intrathecal delivery of rAAV9 and a non-ionic, low-osmolar contrast agent to the patient, wherein the rAAV9 comprises a self-complementary genome including the polynucleotide. The polynucleotide is delivered to, for example, the brain, the spinal cord, a glial cell, an astrocyte and/or a lower motor neuron. The non-ionic, low-osmolar contrast agent is, for example, iobitridol, iohexol, iomeprol, iopamidol, iopentol, iopromide, ioversol or ioxilan. In some embodiments, the polynucleotide is a survival motor neuron (SMN) polynucleotide.
The invention also provides methods of treating a neurological disease in a patient in need thereof comprising intrathecal delivery of a rAAV9 and a non-ionic, low-osmolar contrast agent to the patient, wherein the rAAV9 comprises a self-complementary genome including a therapeutic polynucleotide. The neurological disease is, for example, a neurodegenerative disease such as spinal muscular atrophy or amyotrophic lateral sclerosis. The therapeutic polynucleotide is, for example, an SMN polynucleotide. The SMN polynucleotide is delivered, for example, to the brain, the spinal cord, a glial cell, an astrocyte and/or a lower motor neuron. The non-ionic, low-osmolar contrast agent is, for example, iobitridol, iohexol, iomeprol, iopamidol, iopentol, iopromide, ioversol or ioxilan.


DETAILED DESCRIPTION
Therefore, in one aspect, the invention provides a method for intrathecal delivery of a polynucleotide to the central nervous system of a patient comprising administering a rAAV9 with a genome including the polynucleotide. In some embodiments, a non-ionic, low-osmolar contrast agent is also administered to the patient. The non-ionic, low-osmolar contrast agent increases transduction of target cells in the central nervous system of the patient. In some embodiments, the rAAV9 genome is a self-complementary genome. In other embodiments, the rAAV9 genome is a single-stranded genome.
In some embodiments, the polynucleotide is delivered to brain. Areas of the brain contemplated for delivery include, but are not limited to, the motor cortex and the brain stem. In some embodiments, the polynucleotide is delivered to the spinal cord. In some embodiments, the polynucleotide is delivered to a lower motor neuron. Embodiments of the invention employ rAAV9 to deliver polynucleotides to nerve and glial cells. In some embodiments, the glial cell is a microglial cell, an oligodendrocyte or an astrocyte. In some embodiments, the rAAV9 is used to deliver a polynucleotide to a Schwann cell.
Use of methods and materials of the invention is indicated, for example, for treatment of lower motor neuron diseases such as SMA and ALS as well as Pompe disease, lysosomal storage disorders, Glioblastoma multiforme and Parkinson's disease. Lysosomal storage disorders include, but are not limited to, Activator Deficiency/GM2 Gangliosidosis, Alpha-mannosidosis, Aspartylglucosaminuria, Cholesteryl ester storage disease, Chronic Hexosaminidase A Deficiency, Cystinosis, Danon disease, Fabry disease, Farber disease, Fucosidosis, Galactosialidosis, Gaucher Disease (Type I, Type II, Type III), GM1 gangliosidosis (Infantile, Late infantile/Juvenile, Adult/Chronic), I-Cell disease/Mucolipidosis II, Infantile Free Sialic Acid Storage Disease/ISSD, Juvenile Hexosaminidase A Deficiency, Krabbe disease (Infantile Onset, Late Onset), Metachromatic Leukodystrophy, Mucopolysaccharidoses disorders (Pseudo-Hurler polydystrophy/Mucolipidosis IIIA, MPSI Hurler Syndrome, MPSI Scheie Syndrome, MPS I Hurler-Scheie Syndrome, MPS II Hunter syndrome, Sanfilippo syndrome Type A/MPS III A, Sanfilippo syndrome Type B/MPS III B, Sanfilippo syndrome Type C/MPS III C, Sanfilippo syndrome Type D/MPS III D, Morquio Type A/MPS IVA, Morquio Type B/MPS IVB, MPS IX Hyaluronidase Deficiency, MPS VI Maroteaux-Lamy, MPS VII Sly Syndrome, Mucolipidosis I/Sialidosis, Mucolipidosis IIIC, Mucolipidosis type IV), Multiple sulfatase deficiency, Niemann-Pick Disease (Type A, Type B, Type C), Neuronal Ceroid Lipofuscinoses (CLN6 disease (Atypical Late Infantile, Late Onset variant, Early Juvenile), Batten-Spielmeyer-Vogt/Juvenile NCL/CLN3 disease, Finnish Variant Late Infantile CLN5, Jansky-Bielschowsky disease/Late infantile CLN2/TPP1 Disease, Kufs/Adult-onset NCL/CLN4 disease, Northern Epilepsy/variant late infantile CLN8, Santavuori-Haltia/Infantile CLN1/PPT disease, Beta-mannosidosis, Pompe disease/Glycogen storage disease type II, Pycnodysostosis, Sandhoff Disease/Adult Onset/GM2 Gangliosidosis, Sandhoff Disease/GM2 gangliosidosis—Infantile, Sandhoff Disease/GM2 gangliosidosis—Juvenile, Schindler disease, Salla disease/Sialic Acid Storage Disease, Tay-Sachs/GM2 gangliosidosis, Wolman disease.
In further embodiments, use of the methods and materials is indicated for treatment of nervous system disease such as Rett Syndrome, Alzheimer's Disease, Parkinson's Disease, Huntington's Disease, or for treatment of nervous system injury including spinal cord and brain trauma/injury, stroke, and brain cancers.
In another aspect, the invention provides rAAV genomes. The rAAV genomes comprise one or more AAV ITRs flanking a polynucleotide encoding a polypeptide (including, but not limited to, an SMN polypeptide) or encoding siRNA, shRNA, antisense, and/or miRNA directed at mutated proteins or control sequences of their genes. The polynucleotide is operatively linked to transcriptional control DNAs, specifically promoter DNA and polyadenylation signal sequence DNA that are functional in target cells to form a gene cassette. The gene cassette may also include intron sequences to facilitate processing of an RNA transcript when expressed in mammalian cells.
In some embodiments, the rAAV9 genome encodes a trophic or protective factor for treatment of neurodegenerative disorders, including but not limited to Alzheimer's Disease, Parkinson's Disease, Huntington's Disease along with nervous system injury including spinal cord and brain trauma/injury, stroke, and brain cancers. Non-limiting examples of known nervous system growth factors include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT-4/5), neurotrophin-6 (NT-6), ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), the fibroblast growth factor family (e.g., FGF's 1-15), leukemia inhibitory factor (LIF), certain members of the insulin-like growth factor family (e.g., IGF-1), the neurturins, persephin, the bone morphogenic proteins (BMPs), the immunophilins, the transforming growth factor (TGF) family of growth factors, the neuregulins, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor family (e.g. VEGF 165), follistatin, Hif1, and others. Also generally contemplated are zinc finger transcription factors that regulate each of the trophic or protective factors contemplated herein. In further embodiments, methods to modulate neuro-immune function are contemplated, including but not limited to, inhibition of microglial and astroglial activation through, for example, NFkB inhibition, or NFkB for neuroprotection (dual action of NFkB and associated pathways in different cell types) by siRNA, shRNA, antisense, or miRNA. In still further embodiments, the rAAV9 genome encodes an apoptotic inhibitor (e.g., bcl2, bclxL). Use of a rAAV9 encoding a trophic factor or spinal cord injury modulating protein or a suppressor of an inhibitor of axonal growth (e.g., a suppressor of Nogo [Oertle et al., The Journal of Neuroscience, 23(13):5393-5406 (2003)] is also contemplated for treating spinal cord injury.
For treatment of neurodegenerative disorders such as Parkinson's disease, the rAAV9 genome encodes in various embodiments Aromatic acid dopa decarboxylase (AADC), Tyrosine hydroxylase, GTP-cyclohydrolase 1 (gtpch1), apoptotic inhibitors (e.g., bcl2, bclxL), glial cell line-derived neurotrophic factor (GDNF), the inhibitory neurotransmitter-amino butyric acid (GABA), or enzymes involved in dopamine biosynthesis. In further embodiments, the rAAV9 genome may encode, for example, modifiers of Parkin and/or synuclein.
For treatment of neurodegenerative disorders such as Alzheimer's disease, in some embodiments, methods to increase acetylcholine production are contemplated. In some embodiments, methods of increasing the level of a choline acetyltransferase (ChAT) or inhibiting the activity of an acetylcholine esterase (AchE) are contemplated.
The rAAV9 genome encodes in some embodiments, siRNA, shRNA, antisense, and/or miRNA for use in methods to decrease mutant Huntington protein (htt) expression for treating a neurodegenerative disorder such as Huntington's disease.
The rAAV9 genome encodes in various embodiments siRNA, shRNA, antisense, and/or miRNA for use in for treatment of neurodegenerative disorders such as ALS. Treatment results in a decrease in the expression of molecular markers of disease, such as TNFα, nitric oxide, peroxynitrite, and/or nitric oxide synthase (NOS).
In some embodiments, the vectors encode short hairpin RNAs directed at mutated proteins such as superoxide dismutase for ALS, or neurotrophic factors such as GDNF or IGF1 for ALS or Parkinson's disease.
In some embodiments, use of materials and methods of the invention is indicated for treating neurodevelopmental disorders such as Rett Syndrome. For embodiments relating to Rett Syndrome, the rAAV9 genome may encode, for example, methyl cytosine binding protein 2 (MeCP2).
“Treatment” comprises the step of administering via the intrathecal route an effective dose, or effective multiple doses, of a composition comprising a rAAV of the invention to an animal (including a human being) in need thereof. If the dose is administered prior to development of a disorder/disease, the administration is prophylactic. If the dose is administered after the development of a disorder/disease, the administration is therapeutic. In embodiments of the invention, an effective dose is a dose that alleviates (either eliminates or reduces) at least one symptom associated with the disorder/disease state being treated, that slows or prevents progression to a disorder/disease state, that slows or prevents progression of a disorder/disease state, that diminishes the extent of disease, that results in remission (partial or total) of disease, and/or that prolongs survival. Examples of disease states contemplated for treatment by methods of the invention are set out above.
Combination therapies are also contemplated by the invention. Combination as used herein includes both simultaneous treatment or sequential treatments. Combinations of methods of the invention with standard medical treatments (e.g., riluzole in ALS) are specifically contemplated, as are combinations with novel therapies.
While delivery to an individual in need thereof after birth is contemplated, intrauteral delivery to a fetus is also contemplated.
Transduction with rAAV may also be carried out in vitro. In one embodiment, desired target cells are removed from the subject, transduced with rAAV and reintroduced into the subject. Alternatively, syngeneic or xenogeneic cells can be used where those cells will not generate an inappropriate immune response in the subject.
Suitable methods for the transduction and reintroduction of transduced cells into a subject are known in the art. In one embodiment, cells can be transduced in vitro by combining rAAV with the cells, e.g., in appropriate media, and screening for those cells harboring the DNA of interest using conventional techniques such as Southern blots and/or PCR, or by using selectable markers. Transduced cells can then be formulated into pharmaceutical compositions, and the composition introduced into the subject by various techniques, such as by injection into the spinal cord.
The rAAV genomes of the invention lack AAV rep and cap DNA. AAV DNA in the rAAV genomes (e.g., ITRs) may be from any AAV serotype for which a recombinant virus can be derived including, but not limited to, AAV serotypes AAV-1, AAV-2, AAV-3, AAV-4, AAV-5, AAV-6, AAV-7, AAV-8, AAV-9, AAV-10 and AAV-11. The nucleotide sequences of the genomes of the AAV serotypes are known in the art. For example, the complete genome of AAV-1 is provided in GenBank Accession No. NC_002077; the complete genome of AAV-2 is provided in GenBank Accession No. NC_001401 and Srivastava et al., J. Virol., 45: 555-564 {1983): the complete genome of AAV-3 is provided in GenBank Accession No. NC_1829; the complete genome of AAV-4 is provided in GenBank Accession No. NC_001829; the AAV-5 genome is provided in GenBank Accession No. AF085716; the complete genome of AAV-6 is provided in GenBank Accession No. NC_00 1862; at least portions of AAV-7 and AAV-8 genomes are provided in GenBank Accession Nos. AX753246 and AX753249, respectively; the AAV-9 genome is provided in Gao et al., J. Virol., 78: 6381-6388 (2004); the AAV-10 genome is provided in Mol. Ther., 13(1): 67-76 (2006); and the AAV-11 genome is provided in Virology, 330(2): 375-383 (2004).
In another aspect, the invention provides DNA plasmids comprising rAAV genomes of the invention. The DNA plasmids are transferred to cells permissible for infection with a helper virus of AAV (e.g., adenovirus, E1-deleted adenovirus or herpesvirus) for assembly of the rAAV genome into infectious viral particles with AAV9 capsid proteins. Techniques to produce rAAV particles, in which an AAV genome to be packaged, rep and cap genes, and helper virus functions are provided to a cell are standard in the art. Production of rAAV requires that the following components are present within a single cell (denoted herein as a packaging cell): a rAAV genome, AAV rep and cap genes separate from (i.e., not in) the rAAV genome, and helper virus functions. Production of pseudotyped rAAV is disclosed in, for example, WO 01/83692 which is incorporated by reference herein in its entirety. In various embodiments, AAV capsid proteins may be modified to enhance delivery of the recombinant vector. Modifications to capsid proteins are generally known in the art. See, for example, US 2005/0053922 and US 2009/0202490, the disclosures of which are incorporated by reference herein in their entirety.
A method of generating a packaging cell is to create a cell line that stably expresses all the necessary components for AAV particle production. For example, a plasmid (or multiple plasmids) comprising a rAAV genome lacking AAV rep and cap genes. AAV rep and cap genes separate from the rAAV genome, and a selectable marker, such as a neomycin resistance gene, are integrated into the genome of a cell. AAV genomes have been introduced into bacterial plasmids by procedures such as GC tailing (Samulski et al., 1982, Proc. Natl. Acad. S6. USA, 79:2077-2081), addition of synthetic linkers containing restriction endonuclease cleavage sites (Laughlin et al., 1983, Gene, 23:65-73) or by direct, blunt-end ligation (Senapathy & Carter, 1984, J. Biol. Chem., 259:4661-4666). The packaging cell line is then infected with a helper virus such as adenovirus. The advantages of this method are that the cells are selectable and are suitable for large-scale production of rAAV. Other examples of suitable methods employ adenovirus or baculovirus rather than plasmids to introduce rAAV genomes and/or rep and cap genes into packaging cells.
General principles of rAAV production are reviewed in, for example, Carter, 1992, Current Opinions in Biotechnology, 1533-539; and Muzyczka, 1992, Curr. Topics in Microbial. and Immunol., 158:97-129). Various approaches are described in Ratschin et al., Mol. Cell. Biol. 4:2072 (1984); Hermonat et al., Proc. Natl. Acad. Sci. USA, 81:6466 (1984); Tratschin et al., Mol. Cell. Biol. 5:3251 (1985); McLaughlin et al., J. Virol., 62:1963 (1988); and Lebkowski et al., 1988 Mol. Cell. Biol., 7:349 (1988). Samulski et al. (1989, J. Virol., 63:3822-3828); U.S. Pat. No. 5,173,414; WO 95/13365 and corresponding U.S. Pat. No. 5,658,776; WO 95/13392; WO 96/17947; PCT/US98/18600; WO 97/09441 (PCT/US96/14423); WO 97/08298 (PCT/US96/13872); WO 97/21825 (PCT/US96/20777); WO 97/06243 (PCT/FR96/01064); WO 99/11764; Perrin et al. (1995) Vaccine 13:1244-1250; Paul et al. (1993) Human Gene Therapy 4:609-615; Clark et al. (1996) Gene Therapy 3:1124-1132; U.S. Pat. Nos. 5,786,211; 5,871,982; and 6,258,595. The foregoing documents are hereby incorporated by reference in their entirety herein, with particular emphasis on those sections of the documents relating to rAAV production.
The invention thus provides packaging cells that produce infectious rAAV. In one embodiment packaging cells may be stably transformed cancer cells such as HeLa cells, 293 cells and PerC.6 cells (a cognate 293 line). In another embodiment, packaging cells are cells that are not transformed cancer cells such as low passage 293 cells (human fetal kidney cells transformed with E1 of adenovirus), MRC-5 cells (human fetal fibroblasts). WI-38 cells (human fetal fibroblasts), Vero cells (monkey kidney cells) and FRhL-2 cells (rhesus fetal lung cells).
In other embodiments, the invention provides rAAV9 (i.e., infectious encapsidated rAAV9 particles) comprising a rAAV genome of the invention. In one aspect of the invention, the rAAV genome is a self-complementary genome.
In another aspect, rAAV are provided such as a rAAV9 named “rAAV SMN.” The rAAV SMN genome (nucleotides 980-3336 of SEQ ID NO: 1) has in sequence an AAV2 ITR, the chicken β-actin promoter with a cytomegalovirus enhancer, an SV40 intron, the SMN coding DNA set out in (GenBank Accession Number NM_000344.2), a polyadenylation signal sequence from bovine growth hormone and another AAV2 ITR. Conservative nucleotide substitutions of SMN DNA are also contemplated (e.g., a guanine to adenine change at position 625 of GenBank Accession Number NM_000344.2). The genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome. SMN polypeptides contemplated include, but are not limited to, the human SMN1 polypeptide set out in NCBI protein database number NP_000335.1. Also contemplated is the SMN1-modifier polypeptide plastin-3 (PLS3) [Oprea et al., Science 320(5875): 524-527 (2008)]. Sequences encoding other polypeptides may be substituted for the SMN DNA.
The rAAV may be purified by methods standard in the art such as by column chromatography or cesium chloride gradients. Methods for purifying rAAV vectors from helper virus are known in the art and include methods disclosed in, for example, Clark et al., Hum. Gene Ther., 10(6): 1031-1039 (1999); Schenpp and Clark, Methods Mol. Med., 69: 427-443 (2002); U.S. Pat. No. 6,566,118 and WO 98/09657.
In another aspect, the invention contemplates compositions comprising rAAV of the present invention. In one embodiment, compositions of the invention comprise a rAAV encoding a SMN polypeptide. In other embodiments, compositions of the present invention may include two or more rAAV encoding different polypeptides of interest.
Compositions of the invention comprise rAAV in a pharmaceutically acceptable carrier. The compositions may also comprise other ingredients such as diluents and adjuvants. Acceptable carriers, diluents and adjuvants are nontoxic to recipients and are preferably inert at the dosages and concentrations employed, and include buffers such as phosphate, citrate, or other organic acids; antioxidants such as ascorbic acid; low molecular weight polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as Tween, pluronics or polyethylene glycol (PEG).
Titers of rAAV to be administered in methods of the invention will vary depending, for example, on the particular rAAV, the mode of administration, the treatment goal, the individual, and the cell type(s) being targeted, and may be determined by methods standard in the art. Titers of rAAV may range from about 1×106, about 1×107, about 1×108, about 1×109, about 1×1010, about 1×1011, about 1×1012, about 1×1013 to about 1×1014 or more DNase resistant particles (DRP) per ml. Dosages may also be expressed in units of viral genomes (vg). Dosages may also vary based on the timing of the administration to a human. These dosages of rAAV may range from about 1×1011 vg/kg, about 1×1012, about 1×1013, about 1×1014, about 1×1015, about 1×1016 or more viral genomes per kilogram body weight in an adult. For a neonate, the dosages of rAAV may range from about 1×1011, about 1×1012, about 3×1012, about 1×1013, about 3×1013, about 1×1014, about 3×1014, about 1×1015, about 3×1015, about 1×1016, about 3×1016 or more viral genomes per kilogram body weight.
In another aspect, methods of transducing target cells (including, but not limited to, nerve or glial cells) with rAAV are contemplated by the invention.
The term “transduction” is used to refer to the administration/delivery of a polynucleotide to a target cell either in vivo or in vitro, via a replication-deficient rAAV of the invention resulting in expression of a functional polypeptide by the recipient cell.
Transduction of cells with rAAV of the invention results in sustained expression of polypeptide or RNA encoded by the rAAV. The present invention thus provides methods of administering/delivering rAAV (e.g., encoding SMN protein) of the invention to an animal or a human patient. These methods include transducing nerve and/or glial cells with one or more rAAV of the present invention. Transduction may be carried out with gene cassettes comprising tissue specific control elements. For example, promoters that allow expression specifically within neurons or specifically within astrocytes. Examples include neuron specific enolase and glial fibrillary acidic protein promoters. Inducible promoters under the control of an ingested drug may also be developed.
In some aspects, it is contemplated that the transduction of cells is increased when a vector of the disclosure is used in combination with a contrast agent as described herein relative to the transduction of a vector of the disclosure when not used in combination with a contrast agent. In various embodiments, the transduction of cells is increased by at least about 1%, or at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 120%, at least about 150%, at least about 180%, at least about 200%, at least about 250%, at least about 300%, at least about 350%, at least about 400%, at least about 450%, at least about 500% or more when a vector of the disclosure is used in combination with a contrast agent as described herein, relative to the transduction of a vector of the disclosure when not used in combination with a contrast agent. In further embodiments, the transduction of cells is increased by about 10% to about 50%, or by about 10% to about 100%, or by about 5% to about 10%, or by about 5% to about 50%, or by about 1% to about 500%, or by about 10% to about 200%, or by about 10% to about 300%, or by about 10% to about 400%, or by about 100% to about 500%, or by about 150% to about 300%, or by about 200% to about 500% when a vector of the disclosure is used in combination with a contrast agent as described herein, relative to the transduction of a vector of the disclosure when not used in combination with a contrast agent.
In some aspects, it is contemplated that the transduction of cells is further increased when a vector of the disclosure is used in combination with a contrast agent and when the patient is put in the Trendelenberg position (head down position). In some embodiments, for example, the patients is tilted in the head down position at about 1 degree to about 30 degrees, about 15 to about 30 degrees, about 30 to about 60 degrees, about 60 to about 90 degrees, or about 90 up to about 180 degrees) during or after intrathecal vector infusion. In various embodiments, the transduction of cells is increased by at least about 1%, or at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 120%, at least about 150%, at least about 180%, at least about 200%, at least about 250%, at least about 300%, at least about 350%, at least about 400%, at least about 450%, at least about 500% or more when a vector of the disclosure is used in combination with a contrast agent and Trendelenberg position as described herein, relative to the transduction of a vector of the disclosure when not used in combination with a contrast agent and Trendelenberg position. In further embodiments, the transduction of cells is increased by about 10% to about 50%, or by about 10% to about 100%, or by about 5% to about 10%, or by about 5% to about 50%, or by about 1% to about 500%, or by about 10% to about 200%, or by about 10% to about 300%, or by about 10% to about 400%, or by about 100% to about 500%, or by about 150% to about 300%, or by about 200% to about 500% when a vector of the disclosure is used in combination with a contrast agent and Trendelenberg position as described herein, relative to the transduction of a vector of the disclosure when not used in combination with a contrast agent and Trendelenberg position.
The disclosure also provides aspects wherein intrathecal administration of a vector of the disclosure and a contrast agent to the central nervous system of a patient in need thereof results in an increase in survival of the patient relative to survival of the patient when a vector of the disclosure is administered in the absence of the contrast agent. In various embodiments, administration of a vector of the disclosure and a contrast agent to the central nervous system of a patient in need thereof results in an increase of survival of the patient of at least about 1%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 150%, at least about 200% or more relative to survival of the patient when a vector of the disclosure is administered in the absence of the contrast agent.
The disclosure also provides aspects wherein intrathecal administration of a vector of the disclosure and a contrast agent to the central nervous system of a patient in need thereof put in the Trendelenberg position results in a further increase in survival of the patient relative to survival of the patient when a vector of the disclosure is administered in the absence of the contrast agent and the Trendelenberg position. In various embodiments, administration of a vector of the disclosure and a contrast agent to the central nervous system of a patient in need thereof put in the Trendelberg position results in an increase of survival of the patient of at least about 1%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 150%, at least about 200% or more relative to survival of the patient when a vector of the disclosure is administered in the absence of the contrast agent and the Trendelenberg position.
It will be understood by one of ordinary skill in the art that a polynucleotide delivered using the materials and methods of the invention can be placed under regulatory control using systems known in the art. By way of non-limiting example, it is understood that systems such as the tetracycline (TET on/off) system [see, for example, Urlinger et al., Proc. Nail. Acad. Sci. USA 97(14):7963-7968 (2000) for recent improvements to the TET system] and Ecdysone receptor regulatable system [Palli et al., Eur J. Biochem 270: 1308-1315 (2003] may be utilized to provide inducible polynucleotide expression. It will also be understood by the skilled artisan that combinations of any of the methods and materials contemplated herein may be used for treating a neurodegenerative disease.
The present invention is illustrated by the following examples, wherein Example 1 describes the production of an exemplary rAAV9, Example 2 describes the intrathecal administration of rAAV9, Example 3 describes the increase in survival of SMN mutant mice following intracerebroventricular (ICV) injection of rAAV9 SMN with contrast agent and Example 4 describes motor neuron transduction with a rAAV9 in cynomologus monkeys.
Example 1
The ability of rAAV9 to target and express protein in the central nervous system was evaluated in an in vivo model system. The rAAV genome included in sequence an AAV2 ITR, the chicken β-actin promoter with a cytomegalovirus enhancer, an SV40 intron, green fluorescent protein (GFP) DNA, a polyadenylation signal sequence from bovine growth hormone and another AAV2 ITR, as previously described in Bevan et al., Molecular Therapy, 19(11): 1971-1980 (2011).
Self-complementary AAV9 (AAV9 GFP) was produced by transient transfection procedures using a double-stranded AAV2-ITR-based CB-GFP vector, with a plasmid encoding Rep2Cap9 sequence as previously described [Gao et al., J. Virol., 78: 6381-6388 (2004)] along with an adenoviral helper plasmid pHelper (Stratagene, Santa Clara, Calif.) in 293 cells. The serotype 9 sequence was verified by sequencing and was identical to that previously described. Virus was produced in three separate batches for the experiments and purified by two cesium chloride density gradient purification steps, dialyzed against PBS and formulated with 0.001% Pluronic-F68 to prevent virus aggregation and stored at 4° C. All vector preparations were titered by quantitative PCR using Taq-Man technology. Purity of vectors was assessed by 4-12% sodium dodecyl sulfate-acrylamide gel electrophoresis and silver staining (Invitrogen, Carlsbad, Calif.).
Example 2
Although some neurological disorders are caused by defects in ubiquitously expressed proteins, in other disorders gene expression in the CNS alone may have a substantial impact. The invention contemplates that gene delivery to the CSF can produce transduction along the neuraxis with the added benefit of potentially lowering the required dose. Thus, to effect more localized CNS delivery, intrathecal and/or intracisternal injections of 5.2×10 12 vg/kg of AAV9 GFP and a non-ionic, low-osmolar contrast agent into 5-day-old pigs (n=3 each) were performed, and their brains and spinal cords were examined for GFP expression.
Intrathecal Injection. Farm-bred sows (Sus scrofa domestica) were obtained from a regional farm. Five-day-old (P5) piglets received 0.5 cc/kg ketamine induction anesthesia and then were maintained by mask inhalation of 5% isoflurane in oxygen. Body temperature, electrocardiogram, and respiratory rate were monitored throughout the procedure. For lumbar puncture, piglets were placed prone and the spine was flexed in order to widen the intervertebral spaces. The anterior-superior iliac spines were palpated and a line connecting the two points was visualized. The intervertebral space rostral to this line is  ̃L5-L6. Intraoperative fluoroscopy confirmed rostral-caudal and mediolateral trajectories. Using sterile technique, a 25-gauge needle attached to a 1-ml syringe was inserted. Gentle negative pressure was applied to the syringe as the needle was passed until a clear flash of CSF was visualized. For cisterna puncture, the head of the piglet was flexed while maintaining the integrity of the airway. Fluoroscopy again confirmed adequate trajectory. A 25-gauge needle was passed immediately caudal to the occipital bone, and a flash of clear CSF confirmed entry into the cistern magna.
For vector or control delivery, the syringe was removed while the needle was held in place. A second 1-cc syringe containing either viral solution (5.2×10 12 vg/kg) or PBS was secured and the solution was injected into the intrathecal space at a slow and constant rate. After delivery,  ̃0.25 ml of sterile PBS was flushed through the spinal needle so as to ensure full delivery of reagent. An iohexol radioopaque agent [OmnipaqueTM (iohexol, N,N′-Bis(2,3-dihydroxypropyl)-5-[N(2,3-dihydroxypropyl)-acetamido]-2,4,6-trioldo-isophthalamide), GE Healthcare, Waukesha, Wis.] and recording intrathecal spread with real-time continuous fluoroscopy.
Perfusion and tissue-processing. All subjects were sacrificed between 21 and 24 days post-injection. Subjects were deeply anesthetized by intramuscular injection of Telazol followed by Propofol. A midventral sternal thoracotomy was performed and a cannula was inserted in the aorta through the left ventricle. The right atrium was opened and 0.5-11 of PBS was injected through the cannula by gravity flow, followed by perfusion with 11 of 4% paraformaldehyde in phosphate buffer (pH 7.4). Organs were removed and post-fixed 48 hours in 4% paraformaldehyde before further processing for histological sectioning or stored long-term in 0.1% NaN3 PBS solution.
Histology and microscopy. Spinal cord segments were embedded in 3% agarose before cutting into 40-μm horizontal sections using a Leica VT1200 vibrating microtome (Leica Microsystems, Buffalo Grove, Ill.). Sections were transferred in Tris-buffered saline and stored at 4° C. until processing. Brains were cryoprotected by successive incubation in 10, 20, and 30% sucrose solutions. Once sufficiently cryoprotected (having sunk in 30% sucrose solution), brains were frozen and whole-mounted on a modified Leica SM 2000R sliding microtome (Leica Microsystems) in OCT (Tissue-Tek, Torrance, Calif.) and cut into 40-μm coronal sections.
For immunofluorescent determination of cell types transduced, floating sections were submerged in blocking solution (10% donkey serum, 1% Triton-X100 in Tris-buffered saline) for 1 hour followed by overnight incubation in primary antibody solution at 4° C. The following primary antibodies were used in this study: Rabbit-anti-GFP (1:500; Invitrogen), goat-anti-ChAT (1:100; Millipore, Billerica, Mass.), guinea-pig-anti-GFAP (1:1,000; Advanced Immunochemical, Long Beach, Calif.) and rabbit-anti-Iba1 (1:500; Dako, Carpentaria, Calif.). Primary antibodies were detected using Fitc-, Cy3-, or Cy5-conjugated secondary antibodies (1:1,000; Jackson ImmunoResearch, West Grove, Pa.) and mounted in PVA-DABCO medium.
For immunohistochemical staining, sections were incubated at room temperature in 0.5% H2O2/10% MeOH solution and subsequently blocked and stained as above with rabbit-anti-GFP overnight. Anti-GFP antibodies were detected using biotinylated donkey-anti-rabbit secondary antibody (1:200; Jackson ImmunoResearch) and developed using Vector NovaRed per the provided protocol (Vector Labs, Burlingame, Calif.). Sections were then mounted in Cytoseal 60 medium (Thermo Fisher Scientific, Kalamazoo, Mich.).
Non-neural tissues were cut to  ̃1 cm 3 blocks and cryoprotected by overnight incubation in 30% sucrose solution. They were then embedded in gum tragacanth and flash-frozen in liquid nitrogen-cooled isopentane. Samples were cut by cryostat into 10-12 μm sections and slides stored at −20° C. GFP expression was detected by a similar immunofluorescent protocol as above with the addition of DAPI in secondary antibody solution (1:1,000; Invitrogen).
Fluorescent images were captured using a Zeiss 710 Meta confocal microscope (Carl Zeiss MicroImaging, Thornwood, N.Y.) located at TRINCH and processed with LSM software.
Whole brain sections were scanned to ×40 resolution at the Biopathology Center in the Research Informatics Core at the Research Institute at Nationwide Children's Hospital using an Aperio automated slide scanner (Aperio, Vista, Calif.) and resulting images were processed with ImageScope software.
In all animals, GFP expression was seen in the dorsal root ganglia as well as the spinal cord gray and white matter. Importantly, AAV9 GFP injection into either the cisternal space at the base of the skull or the intrathecal space at L5 resulted in extensive motor neuron transduction and glia at all levels of the spinal cord as examined by in situ hybridization. Large ventral horn neurons were also positive for GFP expression by immunohistochemistry at all levels of spinal cord. Immunofluorescence confirmed that the GFP+ cells expressed the motor neuron marker ChAT.
Finally, to further characterize the pattern of expression following cisternal or intrathecal injection of AAV9-GFP into 5-day-old pigs, brains were examined for transgene expression again using GFP immunofluorescence The regions with the highest levels of GFP expression were cerebellar Purkinje cells, nerve fibers within the medulla as well as discrete nuclei, such as the olivary nucleus. Expression within the rest of the brain was restricted to scattered cells near the meningeal surfaces. Examination of GFP expression in peripheral organs yielded no visible GFP expression indicating that the majority of the virus was localized to the CNS.
Thus, AAV9 injection into the cerebral spinal fluid of young pigs efficiently targeted motor neurons.
Example 3
The effects of in vivo delivery of rAAV9 SMN [see Foust et al., Nature Biotechnology 28(3): 271-274 (2010) and description hereinabove, wherein the sequence of the vector genome insert is shown as nucleotides 980-3336 of SEQ ID NO: 1)] and contrast agent to the cerebral spinal fluid (CSF) of SMN mutant mice was tested.
Briefly, the rAAV9 SMN was mixed with contrast agent, followed by ICV injection to effect placement of the composition to the CSF of SMN mutant mice. As a control experiment, the rAAV9 SMN vector was injected without contrast agent into a separate group of SMN mutant mice.
Results showed that injection of rAAV9 SMN at  ̃108 vg/kg with contrast agent yielded a median survival of SMN mutant mice of 20 days, while injection of an equivalent amount of rAAV9 SMN in the absence of contrast agent yielded no survival.
Injection of rAAV9 SMN at  ̃109 vg/kg with contrast agent yielded a median survival of SMN mutant mice of over 70 days, versus no survival of SMN mutant mice that were injected with an equivalent amount of rAAV9 SMN in the absence of contrast agent.
Finally, injection of rAAV9 SMN at  ̃1010 vg/kg with contrast agent yielded a median survival of SMN mutant mice of over 100 days, versus a median survival of 70 days in SMN mutant mice that were injected with an equivalent amount of rAAV9 SMN in the absence of contrast agent.
Thus, the survival of SMN mutant mice is increased following injection of rAAV9 SMN with contrast agent, relative to the survival of SMN mutant mice following injection of rAAV9 SMN in the absence of contrast agent.
Example 4
Three one year old cynomolgus monkeys received intrathecal injections of 1×1013 vg/Kg rAAV9 encoding a shRNA and GFP. The injection was performed by lumbar puncture into the subarachnoid space of the lumbar thecal sac. The rAAV9 was resuspended with omnipaque (iohexol), an iodinated compound routinely used in the clinical setting. Iohexol is used to validate successful subarachnoid space cannulation and was administered at a dose of 100 mg/Kg. The subject was placed in the lateral decubitus position and the posterior midline injection site at  ̃L4/5 level identified (below the conus of the spinal cord). Under sterile conditions, a spinal needle with stylet was inserted and subarachnoid cannulation was confirmed with the flow of clear CSF from the needle. In order to decrease the pressure in the subarachnoid space, 0.8 ml of CSF was drained, immediately followed by injection with a mixture containing 0.7 mL iohexol (300 mg/ml formulation) mixed with 2.1 mL of virus (2.8 ml total). To investigate if rostral flow distribution of the virus could improve cell transduction in the cervical area, one subject was let recover in the lateral decubitus position, and the second and third subjects were tilted in the Trendelenberg position (head down position). This is a routine procedure when performing CT myelograms in human subjects.
Cynomolgus monkeys injected with virus were euthanized 2 weeks post injection. Animals were anesthetized with sodium pentobarbital at the dose of 80-100 mg/kg intravenously and perfused with saline solution. Brain and spinal cord dissection were performed immediately and tissues were processed either for nucleic acid isolation (snap frozen) or post-fixed in 4% paraformaldehyde and subsequently cryoprotected with 30% sucrose and frozen in isopentane at −65° C. 12 μm coronal sections were collected from lumbar cord using a cryostat for free floating immunostaining with green fluorescent protein (GFP) to identify the cells transduced by the virus and choline acetyl transferase (Chat) to identify the motor neurons. Double positive cells were counted in 10 sections of cervical, thoracic and lumbar cord and their number was normalized to the total number of Chat positive cells in the same segment.
The cell counts revealed that tilting the subjects after virus infusion results in a two-fold (100%) improvement in motor neuron transduction at the thoracic and cervical levels.
While the present invention has been described in terms of various embodiments and examples, it is understood that variations and improvements will occur to those skilled in the art. Therefore, only such limitations as appear in the claims should be placed on the invention.
All documents referred to herein are incorporated by reference in their entirety.

## Claims

1. A composition formulated for intrathecal administration to the spinal cord, wherein the composition comprises: (a) a recombinant AAV9 (rAAV9) comprising an rAAV9 genome comprising a CLN6 gene; and (b) contrast agent.

2. The composition of claim 1, wherein the contrast agent is a non-ionic, low-osmolar contrast agent.

3. The composition of claim 2, wherein the non-ionic, low-osmolar contrast agent is selected from the group consisting of iobitridol, iohexol, iomeprol, iopamidol, iopentol, iopromide, ioversol, ioxilan, and combinations thereof.

4. The composition of claim 2, wherein the non-ionic, low-osmolar contrast agent is iohexol.

5. The composition of claim 1, wherein the rAAV9 genome is a self-complementary genome.