aav-gene-therapy-neurodegeneration

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AAV Gene Therapy for Neurodegeneration

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">aav-gene-therapy-neurodegeneration</th>
</tr>
<tr>
<td class="label">Serotype</td>
<td>Primary Receptor</td>
</tr>
<tr>
<td class="label">AAV1</td>
<td>N-linked sialic acid</td>
</tr>
<tr>
<td class="label">AAV2</td>
<td>Heparan sulfate proteoglycan</td>
</tr>
<tr>
<td class="label">AAV5</td>
<td>N-linked sialic acid</td>
</tr>
<tr>
<td class="label">AAV8</td>
<td>Unknown</td>
</tr>
<tr>
<td class="label">AAV9</td>
<td>N-linked galactose</td>
</tr>
<tr>
<td class="label">AAVrh.10</td>
<td>Unknown</td>
</tr>
<tr>
<td class="label">AAV-PHP.B</td>
<td>Unknown</td>
</tr>
<tr>
<td class="label">AAV-PHP.eB</td>
<td>Unknown</td>
</tr>
<tr>
<td class="label">AAV-DJ</td>
<td>Unknown</td>
</tr>
<tr>
<td class="label">Product</td>
<td>Company</td>
</tr>
<tr>
<td class="label">Zolgensma</td>
<td>Novartis</td>
</tr>
<tr>
<td class="label">Luxturna</td>
<td>Spark Therapeutics</td>
</tr>
<tr>
<td class="label">Glybera</td>
<td>uniQure</td>
</tr>
</table>

Introduction

Aav Gene Therapy For Neurodegeneration is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

...

AAV Gene Therapy for Neurodegeneration

Introduction

Overview

Adeno-associated virus (AAV) gene therapy represents one of the most promising approaches for treating neurodegenerative diseases by delivering therapeutic genes directly to the central nervous system. AAV is a small, non-pathogenic parvovirus that has been engineered to serve as a safe and efficient vector for gene delivery, with multiple FDA-approved gene therapies now on the market [@wang2019]. Unlike other viral vectors, AAV lacks viral genes and replicates inefficiently in human cells, making it inherently safer for therapeutic applications [@daya2008].

The fundamental challenge in treating neurodegenerative diseases like [Alzheimer](/diseases/alzheimers-disease)'s disease (AD), Parkinson's disease (PD), Huntington's disease ([HD](/diseases/huntingtons)), and amyotrophic lateral sclerosis ([ALS](/diseases/amyotrophic-lateral-sclerosis)) is delivering therapeutic agents across the blood-brain barrier (BBB) to reach affected neurons. AAV vectors can be administered via multiple routes—including intravenous injection, intrathecal delivery, and direct brain injection—and have demonstrated the ability to transduce neurons and glial cells with long-lasting expression of therapeutic proteins [@hudry2019].

This page provides a comprehensive overview of AAV gene therapy for neurodegeneration, covering vector biology, delivery strategies, clinical applications, immunogenicity considerations, and manufacturing challenges.

Mechanism of AAV-Mediated Gene Delivery

The process of AAV-mediated gene therapy involves several critical steps: vector design and engineering, delivery to the target tissue, cellular entry and intracellular trafficking, nuclear entry, and transgene expression. Understanding each step is essential for optimizing therapeutic outcomes.

Mermaid diagram (expand to render)

Vector Design and Engineering

AAV vectors are engineered by removing the viral rep and cap genes and replacing them with a therapeutic transgene cassette containing the gene of interest under the control of a tissue-specific promoter. The most commonly used promoters for CNS expression include:

Cytomegalovirus (CMV) promoter: Strong, ubiquitous expression
Synapsin promoter: Neuron-specific expression
GFAP promoter: Astrocyte-specific expression
MeCP2 promoter: Neuronal and glial expression

The choice of promoter significantly impacts both the level and cell-type specificity of transgene expression. For neurodegenerative applications, neuron-specific promoters like synapsin are often preferred to restrict expression to neurons and minimize off-target effects [@gray2011].

AAV vectors can be packaged as either single-stranded (ssAAV) or self-complementary (scAAV) genomes. Self-complementary vectors undergo more rapid transgene expression but have a smaller packaging capacity (~2.5 kb vs. ~4.7 kb for single-stranded), which limits the size of the transgene cassette that can be delivered [@mccarty2008].

AAV Serotypes for CNS Delivery

Different AAV serotypes exhibit distinct tissue tropisms based on their capsid protein interactions with cell surface receptors. For neurodegenerative disease applications, the choice of serotype is critical for achieving efficient transduction of target cells within the brain and spinal cord.

AAV9: The Gold Standard for CNS Delivery

AAV9 has emerged as the preferred serotype for neurodegenerative disease applications due to its unique ability to cross the BBB following intravenous administration in non-human primates and humans [@foust2009]. In 2019, the FDA approved Zolgensma (onasemnogene abeparvovec), an AAV9-based gene therapy for spinal muscular atrophy (SMA), demonstrating the clinical viability of this approach for CNS diseases [@mendell2017].

AAV9 can transduce both neurons and glial cells, including astrocytes and microglia, making it suitable for diseases affecting multiple cell types. Studies in non-human primates have shown that intravenous AAV9 administration results in widespread transduction throughout the brain and spinal cord, with particular efficiency in motor neurons [@bevan2011].

Engineered Variants for Enhanced BBB Crossing

Several engineered AAV variants have been developed to improve BBB penetration:

AAV-PHP.B and AAV-PHP.eB: Engineered variants that show exceptional BBB crossing in mice but have limited transduction in non-human primates and humans [@deverman2016]
AAV.MecD: A rationally engineered variant showing improved CNS delivery in primates
AAV.CLN3: Optimized for lysosomal enzyme delivery

Delivery Routes to the Brain

The route of AAV administration significantly impacts distribution, transduction efficiency, and safety. Each approach has distinct advantages and limitations.

Intravenous (Systemic) Delivery

Intravenous AAV9 administration leverages the natural ability of this serotype to cross the BBB and achieve widespread CNS transduction. This approach is minimally invasive and suitable for conditions requiring global brain delivery.

Advantages:

Non-invasive (peripheral infusion)
Achieves widespread CNS distribution
Suitable for pediatric and adult patients

Limitations:

Requires high doses (10^14-10^15 vg/kg)
Liver sequestration reduces CNS delivery
Potential immunogenicity from systemic exposure

Clinical trials for giant axonal neuropathy (GAN) and AADC deficiency have demonstrated safety and efficacy of intravenous AAV9 delivery [@hudry2019a].

Intrathecal Delivery

Intrathecal (IT) administration involves injection into the cerebrospinal fluid (CSF) surrounding the spinal cord, bypassing the BBB to deliver vectors directly to the CNS. This route is particularly effective for targeting motor neurons and spinal cord structures.

Advantages:

Bypasses BBB
Lower doses required than IV
Excellent motor neuron transduction

Limitations:

Invasive procedure (lumbar puncture)
Limited brain distribution
Risk of CSF leak and infection

The FDA-approved SMA therapies Zolgensma (intravenous) and Spinraza (nusinersen, an ASO) both utilize approaches that target the CNS via CSF or systemic delivery.

Intraparenchymal Injection

Direct injection into brain parenchyma allows precise targeting of specific brain regions. This approach is used for conditions requiring localized delivery, such as Parkinson's disease (targeting the striatum or substantia nigra).

Advantages:

Precise regional targeting
Lower systemic exposure
Reduced immunogenicity

Limitations:

Highly invasive (stereotactic surgery)
Limited distribution from injection site
Risk of tissue damage

Intracisternal and Intraventricular Delivery

Delivery into the cisterna magna or cerebral ventricles provides broader CSF distribution than intrathecal injection, potentially achieving more widespread brain coverage.

Clinical Applications in Neurodegeneration

Multiple clinical programs are advancing AAV gene therapy for neurodegenerative diseases, spanning FDA-approved products and ongoing trials.

FDA-Approved AAV Gene Therapies with CNS Impact

Parkinson's Disease Gene Therapy Programs

Parkinson's disease is a primary target for AAV gene therapy due to its well-defined neuroanatomy and established delivery targets.

AAV2-AADC (VY-AADC01, Voyager Therapeutics/Pfizer):

Delivers aromatic L-amino acid decarboxylase (AADC) enzyme to the striatum
Converts levodopa to dopamine in the brain
Phase I/II trials showed improved motor function and reduced levodopa requirements [@mittermeyer2012]
Ongoing Phase III development

AAV2-GAD (GAD gene therapy, Neurologix):

Delivers glutamic acid decarboxylase (GAD) to the subthalamic nucleus
Increases GABA production, reducing excessive motor circuit activity
Phase II trial showed significant improvement in "off" medication Unified Parkinson's Disease Rating Scale (UPDRS) scores [@lewitt2011]

AAV2-NTN (CERE-120, Cerevel):

Delivers neurturin (NTN), a neurotrophic factor, to the striatum
Aimed at protecting and restoring dopaminergic neurons
Completed Phase II trials

Huntington's Disease

AAV5-miHTT (uniQure/Roche):

Delivers microRNA targeting mutant huntingtin (HTT) mRNA
Reduces production of toxic huntingtin protein
Phase I/II trials demonstrated dose-dependent reduction of mutant HTT protein in CSF [@tabrizi2022]
Uses AAV5 serotype with intrastriatal injection

Alzheimer's Disease

AAV gene therapy for AD focuses on delivering neurotrophic factors or modifying amyloid/tau pathology:

AAV-[BDNF](/proteins/bdnf-protein): Delivers brain-derived neurotrophic factor to support neuronal survival
AAV-NGF: Delivers nerve growth factor to basal forebrain cholinergic neurons (completed trials)
AAV-anti-Aβ: Delivers anti-amyloid antibodies or Aβ-degrading enzymes

GBA-Parkinson's Disease

PR001 (Prevail Therapeutics/Lilly, LY3884961):

Delivers functional GBA gene to the CNS
Aims to correct Gaucher disease-associated parkinsonism
Uses AAV9 with intrathecal delivery
Phase I/II trial ongoing [@mullard2022]

Amyotrophic Lateral Sclerosis (ALS)

AAV-[SOD1](/proteins/sod1-protein): Delivers RNAi or antisense constructs to silence mutant SOD1 (ongoing trials)
AAV-FUS: Targeting FUS mutations using gene silencing approaches
AAV-ATXN2: Targeting ATXN2 as a therapeutic target

Immunogenicity and Pre-existing Immunity

A major challenge for AAV gene therapy is the prevalence of pre-existing neutralizing antibodies (NAbs) in the human population. These antibodies develop from prior exposure to wild-type AAV and can significantly reduce the efficacy of AAV vector delivery.

Pre-existing Antibody Prevalence

Seroprevalence studies show that 30-60% of adults have detectable NAbs against AAV2, with lower rates for other serotypes. This prevalence varies by geography and age [@calcedo2009]. Patients with high NAb titers may be excluded from AAV therapy due to concerns about reduced efficacy or adverse immune reactions.

Strategies to Mitigate Immunogenicity

Capsid engineering: Mutations in surface residues can reduce antibody recognition

Alternative serotypes: Using less common serotypes can evade NAbs

Immunosuppression: Short courses of corticosteroids before and after delivery

Empty capsid removal: Purifying vector preparations to remove empty capsids reduces immune stimulation

Novel variants: Engineered variants like AAVLK03 show reduced seroprevalence

Cellular Immune Responses

Even in seronegative patients, cellular immune responses against AAV capsid can develop. CD8+ T cells targeting infected cells can eliminate transduced cells, reducing long-term expression. This was observed in early hemophilia trials and is managed with immune suppression [@mingozzi2013].

Manufacturing Challenges

Scaling AAV production for clinical and commercial use presents significant challenges:

Production Systems

Transient transfection:HEK293 cells with triple transfection (rep/cap, helper, transgene). Standard for early-phase trials but difficult to scale
Producer cell lines: Stable cell lines expressing rep/cap and containing the transgene cassette. More scalable but development-intensive
Baculovirus/insect cell: SF9 cells with baculovirus system. Highly scalable, used for some commercial products

Purification Challenges

CsCl gradient: Traditional but low-throughput
Affinity chromatography: AVB sepharose for purification, high purity
Ion exchange: Additional purification step
Empty/full capsid separation: Critical for safety, achieved via density gradient or chromatography

Manufacturing Scale-Up

The high doses required for CNS delivery (10^14-10^15 vg/kg for systemic, 10^13-10^14 vg for intrathecal) create manufacturing demands that have constrained commercial supply. Manufacturing capacity has improved significantly, with multiple dedicated viral vector manufacturing facilities now operational.

Safety Considerations

Acute Toxicity

Liver toxicity: Monitor liver enzymes; transient elevation common
Thrombocytopenia: Observed with high-dose systemic delivery
Neurotoxicity: Rare but potentially severe, especially with direct brain injection

Long-term Expression Concerns

Insertional mutagenesis: AAV integrates at low rates into the host genome; clinical experience to date shows minimal oncogenic risk
Immune response to transgene: Particularly relevant for secreted proteins
Dysregulated expression: Promoter silencing or overexpression concerns

Future Directions

The field of AAV gene therapy for neurodegeneration continues to evolve with several promising directions:

Next-generation capsids: Engineered variants with enhanced CNS tropism and reduced immunogenicity

Regulatory element optimization: Improved promoters and enhancers for regulated, cell-type-specific expression

Combination approaches: AAV delivery combined with small molecules, antibodies, or cell therapy

Repeat dosing: Strategies to enable re-administration if needed

Gene editing: Using AAV to deliver CRISPR-Cas9 components for precise gene correction

Next-Generation Engineered Capsids

The field has moved beyond natural serotypes toward rationally engineered and directed evolution-derived capsids with enhanced CNS properties.

AAV-PHP.eB and the TRACER Platform

Chan et al. developed the TRACER (Tropism Redirection of AAV by Cell-type-specific Expression of RNA) platform using Cre-dependent selection in transgenic mice to identify capsid variants with dramatically enhanced BBB crossing[@deverman2016]. AAV-PHP.eB achieves 40-fold greater CNS transduction than AAV9 in mice after intravenous injection, enabling whole-brain gene delivery at substantially lower doses. However, AAV-PHP.eB's BBB crossing depends on the Ly6a (SCA-1) receptor, which is expressed on mouse but not primate brain endothelium[@huang2019]. This species restriction has limited its clinical translation.

AAV.CAP-B10

To overcome PHP.eB's species restriction, Goertsen et al. used directed evolution in marmosets to engineer AAV.CAP-B10, which shows enhanced BBB crossing in non-human primates[@goertsen2022]. CAP-B10 achieves broadly distributed neuronal transduction after intravenous delivery in marmosets, representing a critical step toward clinically translatable engineered capsids. The variant maintains efficient production and packaging characteristics.

AAVHSC (Hematopoietic Stem Cell-Derived AAV)

AAVHSC variants, isolated from human hematopoietic stem cells, show natural ability to cross the human BBB with reduced immunogenicity compared to conventional serotypes. These naturally occurring variants have lower pre-existing NAb seroprevalence in the human population, potentially expanding the eligible patient pool.

AAV-PHP.S for Peripheral Nervous System

AAV-PHP.S was engineered specifically for peripheral nervous system (PNS) targeting, achieving efficient transduction of dorsal root ganglia and enteric neurons after systemic delivery[@deverman2016]. This is relevant for neurodegenerative diseases with PNS involvement, including Parkinson's disease (enteric [alpha-synuclein](/proteins/alpha-synuclein) pathology) and ALS (motor neuron degeneration).

Key Companies in CNS Gene Therapy

Voyager Therapeutics (NASDAQ: VYGR)

Voyager pioneered the AAV2-AADC (VY-AADC) program for Parkinson's disease, demonstrating that direct MRI-guided delivery of AADC to the putamen restores dopamine synthesis capacity[@mittermeyer2012]. The program was licensed to Neurocrine Biosciences in 2020. Voyager's current platform focuses on engineered AAV capsids identified through their TRACER screening technology, with programs in Friedreich's ataxia and other CNS indications.

Passage Bio (NASDAQ: PASG)

Passage Bio develops intracisternal magna-delivered AAV gene therapies for monogenic CNS diseases. Their pipeline includes PBGM01 for GM1 gangliosidosis, PBFT02 for frontotemporal dementia (FTD) caused by GRN mutations, and PBKR03 for Krabbe disease. The FTD program is particularly relevant — delivering functional progranulin via AAV to compensate for GRN haploinsufficiency could address a significant subset of FTD cases[@hinderer2020].

Prevail Therapeutics (Eli Lilly)

Acquired by Eli Lilly in 2020, Prevail develops AAV gene therapies targeting GBA1-associated neurodegeneration. Their lead program PR001 (LY3884961) delivers functional glucocerebrosidase (GCase) to the CNS via intracisternal injection, targeting both GBA-Parkinson's disease and neuronopathic Gaucher disease[@mullard2022]. GBA1 mutations are the most common genetic risk factor for Parkinson's, making this program potentially impactful for a large patient population.

uniQure (NASDAQ: QURE)

uniQure's AMT-130 is an AAV5-based gene therapy delivering microRNA targeting mutant huntingtin for Huntington's disease. Phase I/II results showed dose-dependent reduction of mutant HTT protein in CSF, with encouraging safety data following intrastriatal delivery[@tabrizi2022]. uniQure's manufacturing expertise — leveraging their baculovirus/Sf9 insect cell production platform — addresses a key bottleneck in the field.

CBS/PSP-Specific Gene Therapy Considerations

Corticobasal syndrome and progressive supranuclear palsy present both unique opportunities and challenges for AAV gene therapy:

Therapeutic Targets for 4R-Tauopathies

MAPT knockdown: AAV-delivered anti-tau microRNAs or shRNAs could reduce tau production, the fundamental driver of CBS/PSP pathology. DeVos et al. demonstrated that AAV-delivered anti-tau antisense reduces tau and prevents neurodegeneration in P301S mice[@devos2017]

Autophagy enhancement: AAV-TFEB (transcription factor EB) delivery could enhance autophagic clearance of 4R-tau aggregates, addressing the proteostatic failure central to these tauopathies

Neurotrophic support: AAV-BDNF or AAV-GDNF targeting the brainstem and basal ganglia — regions most affected in PSP — could provide neuroprotective support during disease progression

Delivery Challenges

CBS/PSP affects distributed cortical and subcortical structures (motor cortex, basal ganglia, brainstem, cerebellum), requiring broad CNS coverage rather than focal delivery. This favors:

Intrathecal AAV9 for widespread CSF-mediated distribution
Engineered BBB-crossing capsids (CAP-B10 or successors) for intravenous delivery
Combination of intrathecal + intravenous for maximal coverage

Current Limitations

No AAV gene therapy trials specifically target CBS or PSP as of 2025. However, the MAPT knockdown approaches being developed for AD-tauopathy (ION717/BIIB080, though ASO-based rather than AAV) provide proof-of-concept for tau reduction strategies. Translation to AAV-based MAPT silencing in 4R-tauopathies represents a high-priority therapeutic opportunity.

External Links

[ClinicalTrials.gov - AAV Gene Therapy](https://clinicaltrials.gov/search?cond=neurodegenerative+disease&intr=AAV+gene+therapy)
[FDA - Gene Therapy Clinical Research](https://www.fda.gov/vaccines-blood-biologics/cellular-gene-therapy-products)
[American Society of Gene & Cell Therapy](https://www.asgct.org/)
[NIH - Gene Therapy](https://www.ncbi.nlm.nih.gov/genetherapy/)

References

[Wang D, Tai PWL, Gao G, Adeno-associated virus vector as a platform for gene therapy delivery (2019)](https://doi.org/10.1038/s41573-019-0012-7)

[Daya S, Berns KI, Gene therapy using adeno-associated virus vectors (2008)](https://doi.org/10.1128/CMR.00008-08)

[Hudry E, Vandenberghe LH, Therapeutic AAV Gene Transfer to the Nervous System: A Clinical Reality (2019)](https://doi.org/10.1016/j.neuron.2019.02.017)

[Gray SJ, Matagne V, Bachaboina L, et al, Preclinical differences of intravascular AAV9 delivery to neurons and glia: a comparative study of adult mice and nonhuman primates (2011)](https://doi.org/10.1038/mt.2011.72)

[McCarty DM, Self-complementary AAV vectors; advances and applications (2008)](https://doi.org/10.1038/mt.2008.171)

[Foust KD, Nurre E, Montgomery CL, et al, Intravascular AAV9 preferentially targets neonatal neurons and adult astrocytes (2009)](https://doi.org/10.1038/nbt.1515)

[Mendell JR, Al-Zaidy S, Shell R, et al, Single-Dose Gene-Replacement Therapy for Spinal Muscular Atrophy (2017)](https://doi.org/10.1056/NEJMoa1706198)

[Bevan AK, Duque S, Foust KD, et al, Systemic gene delivery in large species for targeting spinal cord and brain (2011)](https://doi.org/10.1038/mt.2011.157)

[Deverman BE, Pravdo PL, Simpson BP, et al, Cre-dependent selection yields AAV variants for widespread gene transfer to the adult brain (2016)](https://doi.org/10.1038/nbt.3440)

[Hudry E, Vandenberghe LH, Therapeutic AAV Gene Transfer to the Nervous System: A Clinical Reality (2019)](https://doi.org/10.1016/j.neuron.2019.02.017)

[Mittermeyer G, Christine CW, Rosenbluth KH, et al, Long-term evaluation of AAV2-AADC gene therapy for Parkinson's disease (2012)](https://doi.org/10.1212/WNL.0b013e31826a5a0f)

[LeWitt PA, Rezai AR, Leehey MA, et al, AAV2-GAD gene therapy for advanced Parkinson's disease: a double-blind, sham-surgery controlled, randomised trial (2011)](https://doi.org/10.1016/S1474-4422(11)

[Tabrizi SJ, Leavitt BR, Kordasiewicz H, et al, First-in-Human Study of AAV5-miHTT Gene Therapy for Huntington's Disease (2022)](https://doi.org/10.1002/ana.26308)

[Mullard A, Gene therapy for GBA-associated Parkinson's disease (2022)](https://doi.org/10.1038/d41573-021-00209-1)

[Calcedo R, Vandenberghe LH, Gao G, et al, Worldwide epidemiology of neutralizing antibodies to adeno-associated viruses (2009)](https://doi.org/10.1086/595830)

[Mingozzi F, High KA, Immune responses to AAV vectors: overcoming barriers to successful gene therapy (2013)](https://doi.org/10.1182/blood-2013-01-306647)

[Huang Q, Chan KY, Tobey IG, et al, Delivering genes across the blood-brain barrier: LY6A, a novel cellular receptor for AAV-PHP.B capsids (2019)](https://doi.org/10.1371/journal.pone.0225206)

[Goertsen D, Flytzanis NC, Goeden N, et al, AAV capsid variants with brain-wide transgene expression and decreased liver targeting after intravenous delivery in mouse and marmoset (2022)](https://doi.org/10.1038/s41593-021-00969-4)

[Hinderer C, Miller R, Dyer C, et al, Adeno-associated virus serotype 1-based gene therapy for FTD caused by GRN mutations (2020)](https://doi.org/10.1002/ana.25394)

[DeVos SL, Miller RL, Bhatt N, et al, Tau reduction prevents neuronal loss and reverses pathological tau deposition and seeding in mice with tauopathy (2017)](https://doi.org/10.1126/scitranslmed.aag0481)

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

[Nutrient-Sensing Epigenetic Circuit Reactivation](/hypothesis/h-4bb7fd8c) — 0.79 · Target: SIRT1
[CYP46A1 Overexpression Gene Therapy](/hypothesis/h-2600483e) — 0.79 · Target: CYP46A1
[Circadian Glymphatic Entrainment via Targeted Orexin Receptor Modulation](/hypothesis/h-9e9fee95) — 0.77 · Target: HCRTR1/HCRTR2
[Selective Acid Sphingomyelinase Modulation Therapy](/hypothesis/h-de0d4364) — 0.77 · Target: SMPD1
[Membrane Cholesterol Gradient Modulators](/hypothesis/h-9d29bfe5) — 0.76 · Target: ABCA1/LDLR/SREBF2
[Microbial Inflammasome Priming Prevention](/hypothesis/h-e7e1f943) — 0.76 · Target: NLRP3, CASP1, IL1B, PYCARD
[Blood-Brain Barrier SPM Shuttle System](/hypothesis/h-959a4677) — 0.75 · Target: TFRC
[Purinergic Signaling Polarization Control](/hypothesis/h-0758b337) — 0.74 · Target: P2RY1 and P2RX7

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aav-gene-therapy-neurodegeneration

AAV Gene Therapy for Neurodegeneration

Introduction

Overview

AAV Gene Therapy for Neurodegeneration

Introduction

Overview

Mechanism of AAV-Mediated Gene Delivery

Vector Design and Engineering

AAV Serotypes for CNS Delivery

AAV9: The Gold Standard for CNS Delivery

Engineered Variants for Enhanced BBB Crossing

Delivery Routes to the Brain

Intravenous (Systemic) Delivery

Intrathecal Delivery

Intraparenchymal Injection

Intracisternal and Intraventricular Delivery

Clinical Applications in Neurodegeneration

FDA-Approved AAV Gene Therapies with CNS Impact

Parkinson's Disease Gene Therapy Programs

Huntington's Disease

Alzheimer's Disease

GBA-Parkinson's Disease

Amyotrophic Lateral Sclerosis (ALS)

Immunogenicity and Pre-existing Immunity

Pre-existing Antibody Prevalence

Strategies to Mitigate Immunogenicity

Cellular Immune Responses

Manufacturing Challenges

Production Systems

Purification Challenges

Manufacturing Scale-Up

Safety Considerations

Acute Toxicity

Long-term Expression Concerns

Future Directions

Next-Generation Engineered Capsids

AAV-PHP.eB and the TRACER Platform

AAV.CAP-B10

AAVHSC (Hematopoietic Stem Cell-Derived AAV)

AAV-PHP.S for Peripheral Nervous System

Key Companies in CNS Gene Therapy

Voyager Therapeutics (NASDAQ: VYGR)

Passage Bio (NASDAQ: PASG)

Prevail Therapeutics (Eli Lilly)

uniQure (NASDAQ: QURE)

CBS/PSP-Specific Gene Therapy Considerations

Therapeutic Targets for 4R-Tauopathies

Delivery Challenges

Current Limitations

See Also

External Links

References

Related Hypotheses