John Forsayeth

• PhD
• Professor (Full) at University of California, San Francisco

Alcohol use disorder (AUD) exacts enormous personal, social and economic costs globally. Return to alcohol use in treatment-seeking patients with AUD is common, engendered by a cycle of repeated abstinence-relapse episodes even with use of currently available pharmacotherapies. Repeated ethanol use induces dopaminergic signaling neuroadaptations in...

Osteoarthritis results in chronic pain and loss of function. Proinflammatory cytokines create both osteoarthritis pathology and pain. Current treatments are poorly effective, have significant side effects, and have not targeted the cytokines central to osteoarthritis development and maintenance. Interleukin-10 is an anti-inflammatory cytokine that...

Niemann-Pick disease type A (NPD-A) is a lysosomal storage disorder characterized by neurodegeneration and early death. It is caused by loss-of-function mutations in the gene encoding for acid sphingomyelinase (ASM), which hydrolyzes sphingomyelin into ceramide. Here, we evaluated the safety of cerebellomedullary (CM) cistern injection of adeno-ass...

Here we evaluated the utility of MRI to monitor intrathecal infusions in nonhuman primates. Adeno-associated virus (AAV) spiked with gadoteridol, a gadolinium-based MRI contrast agent, enabled real-time visualization of infusions delivered either via cerebromedullary cistern, lumbar, cerebromedullary and lumbar, or intracerebroventricular infusion....

The present study was designed to characterize transduction of non-human primate brain and spinal cord with a modified adeno-associated virus serotype 2, incapable of binding to the heparan sulfate proteoglycan receptor, referred to as AAV2-HBKO. AAV2-HBKO was infused into the thalamus, intracerebroventricularly or via a combination of both intrace...

Here we advance the hypothesis that Parkinson's disease (PD) is fundamentally a failure of trophic support for specific classes of neurons, primarily catecholaminergic. Evidence from our laboratory provides a framework into which a broad array of findings from many quarters can be integrated into a general theory that offers testable hypotheses to...

Background and purpose: Brain arteriovenous malformation (bAVM) is an important risk factor for intracranial hemorrhage. Current therapies are associated with high morbidities. Excessive vascular endothelial growth factor has been implicated in bAVM pathophysiology. Because soluble FLT1 binds to vascular endothelial growth factor with high affinit...

In Parkinson’s disease (PD), aromatic L-amino acid decarboxylase (AADC) is the rate-limiting enzyme in the conversion of L-DOPA (Sinemet) to dopamine (DA). Previous studies in PD animal models demonstrated that lesion of dopaminergic neurons is associated with profound loss of AADC activity in the striatum, blocking efficient conversion of L-DOPA t...

AADC activity (pmol/mg protein/min) and monoamine (ng/mg protein) levels of control and PD human brain tissue. (PDF)

Huntington’s disease (HD) is caused by a toxic gain-of-function associated with the expression of the mutant huntingtin (htt) protein. Therefore, the use of RNA interference to inhibit Htt expression could represent a disease-modifying therapy. The potential of two recombinant adeno-associated viral vectors (AAV), AAV1 and AAV2, to transduce the co...

Convection-enhanced delivery (CED) has been developed as a drug delivery strategy and represents a powerful methodology for targeted therapy in the brain. Our group has extensively studied and refined this approach for distributing various agents, including small molecules, macromolecules, viral particles, nanoparticles, and liposomal drugs into th...

Figure S1. Fused imaging of GFP expression and gadolinium-enhanced infusate Figure S2. Differential innate immune status Figure S3. Cellular Tropism Figure S4. Axonal transport to midbrain

Huntington disease (HD) is an autosomal dominant neurodegenerative disease caused by a CAG-trinucleotide repeat expansion in a coding exon of a single allele in the HTT locus. In HD, the resulting polyglutamine (polyQ) expansion confers a toxic gain-of-function to the mutant huntingtin protein (mHTT). Reduction of expression of mHTT using gene sile...

Relapsing-remitting multiple sclerosis is commonly associated with motor impairments, neuropathic pain, fatigue, mood disorders, and decreased life expectancy. However, preclinical pharmacological studies predominantly rely on clinical scoring of motor deficit as the sole behavioral endpoint. Thus, the translational potential of these studies is li...

The use of viral vectors to express therapeutics genes in Parkinson’s disease (PD) trials has been hindered by a lack of understanding of the principles that guide effective distribution of vectors within the basal ganglia, even when we have a strong expectation of effi cacy based on experimentation in animal models.The major problems we have faced...

A pilot study in nonhuman primates (NHP) was conducted in which two Rhesus macaques received bilateral parenchymal infusions of adeno-associated virus serotype 9 encoding green fluorescent protein (AAV9-GFP) into each putamen. The post-surgical in-life was restricted to 3 weeks in order to minimize immunotoxicity expected to arise from expression o...

Gene transfer technology offers great promise as a potential therapeutic approach to the brain but has to be viewed as a very complex technology. Success of ongoing clinical gene therapy trials depends on many factors such as selection of the correct genetic and anatomical target in the brain. In addition, selection of the viral vector capable of t...

Background & Purpose: Brain arteriovenous malformation (bAVM) is a risk factor for intracranial hemorrhage. Current therapies are associated with high morbidities. We tested a minimally invasive gene therapy using an adeno-associated viral vector (AAV9) to intravenously (IV) deliver an anti-angiogenic agent, soluble FLT1 (sFLT1), to two bAVM mouse...

Accessing cerebrospinal fluid (CSF) from the cranio-cervical junction through the posterior atlanto-occipital membrane via cerebellomedullary injection (also known as cisternal puncture or cisterna magna injection) has become a standard procedure in preclinical studies. Such delivery provides broader coverage to the central and peripheral nervous s...

Adeno-associated virus serotype 2 (AAV2) has previously been reported to be a slowly uncoating virus in peripheral tissues, but persistence of intact vector in primate brain has not been explored. Because some neurological gene therapies may require re-administration of the same vector to patients, it seems important to understand the optimal timef...

There is an urgent need to develop nanocarriers for the treatment of glioblastoma multiforme (GBM). Using co-registered positron emission tomography (PET) and magnetic resonance (MR) images, here we performed systematic studies to investigate how a nanocarrier's size affects the pharmacokinetics and biodistribution in rodents with a GBM xenograft....

Widespread distribution of gene products at clinically relevant levels throughout the central nervous system (CNS) without involving peripheral organs is still a challenge. Previous work demonstrated that infusion of adeno-associated virus (AAV) serotypes 9 (AAV9) and 7 (AAV7) into the cerebrospinal fluid (CSF) via cisterna magna of nonhuman primat...

Cerebral infusion of AAV9 vectors encoding non-self proteins results in the initiation of a robust immune reaction at the site of injection due to the vector's ability to transduce antigen-presenting cells in the brain [1]. Infusion of AAV9 encoding a human gene, aromatic L-amino acid decarboxylase (hAADC), elicited an initial innate immune activat...

AAV-based gene therapy has considerable potential as a therapeutic tool to treat many monogenic diseases by restoring deficient expression of key genes after a single injection of an AAV hosting a functional copy of the gene. Under some circumstances, these diseases may need more than a single administration of the AAV-based therapeutic agent. One...

Progressively blunted response to L-DOPA in Parkinson's disease (PD) is a critical factor that complicates long-term pharmacotherapy in view of the central importance of this drug in management of the PD-related motor disturbance. This phenomenon is likely due to progressive loss of one of the key enzymes involved in the biosynthetic pathway for do...

mt is a cross-disciplinary biomedical journal devoted to publishing the most exciting advances in pharmacology and therapeutics, as they pertain to advances in translational and clinical medicine. It is recognized as one of the most prestigious journals in the field. With an impact factor of 6.825*, mt ranks in the top 4.2% of scientific journals i...

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare, autosomal-recessive neurological disorder caused by mutations in the DDC gene that leads to an inability to synthesize catecholamines and serotonin. As a result, patients suffer compromised development, particularly in motor function. A recent gene replacement clinical trial explored...

Glioblastoma represents the most common primary brain tumor, and among the most lethal of cancers. The axis linking receptor tyrosine kinases and phosphatidylinositol 3' kinase to the mammalian target of rapamycin (mTOR) is activated in a majority of glioblastomas, suggesting mTOR as a prominent target for therapy. A new class of mTOR kinase inhibi...

Moderate social consumption of alcohol is common; however, only a small percentage of individuals transit from social to excessive, uncontrolled alcohol drinking. This suggests the existence of protective mechanisms that prevent the development of alcohol addiction. Here, we tested the hypothesis that the glial cell line-derived neurotrophic factor...

Abstract In cases of malignant brain tumors, infiltrating tumor cells that exist at the tumor-surrounding brain tissue always escape from cytoreductive surgery and, protected by blood-brain barrier (BBB), survive the adjuvant chemoradiotherapy, eventually leading to tumor recurrence. Local interstitial delivery of chemotherapeutic agents is a promi...

When nanoparticles/proteins are infused into the brain, they are often transported to distal sites in a manner that is dependent both on the characteristics of the infusate and the region targeted. We have previously shown that adeno-associated virus (AAV) is disseminated within the brain by perivascular flow and also by axonal transport. Perivascu...

Aim: We sought to evaluate nanoliposomal irinotecan as an intravenous treatment in an orthotopic brain tumor model. Materials & methods: Nanoliposomal irinotecan was administered intravenously in the intracranial U87MG brain tumor model in mice, and irinotecan and SN-38 levels were analyzed in malignant and normal tissues. Therapy studies were p...

Many studies have demonstrated that adeno-associated virus serotype 9 (AAV9) transduces astrocytes and neurons when infused into rat or nonhuman primate (NHP) brain. We previously showed in rats that transduction of antigen-presenting cells (APC) by AAV9 encoding a foreign protein triggered a full neurotoxic immune response. Accordingly, we asked w...

We recently demonstrated that axonal transport of adeno-associated virus (AAV) is serotype-dependent. Thus, AAV serotype 2 (AAV2) is anterogradely transported (e.g., from cell bodies to nerve terminals) in both rat and non-human primate (NHP) brain. In contrast, AAV serotype 6 (AAV6) is retrogradely transported from terminals to neuronal cell bodie...

Designing stable drug nanocarriers, 10-30 nm in size, would have significant impact on their transport in circulation, tumor penetration and therapeutic efficacy. In the present study, biological properties of 3-helix micelles loaded with 8 wt% doxorubicin (DOX), ~15 nm in size, were characterized to validate their potential as a nanocarrier platfo...

In the present study, we compared the therapeutic effect of tumor-selective retroviral replicating vectors (RRV) expressing the yeast cytosine deaminase (CD) delivered by convection-enhanced delivery (CED) or simple injection, followed by systemic administration of the pro-drug, 5-fluorocytosine (5-FC). Treatment with RRV-CD and systemic 5-FC signi...

Protein aggregation as a result of misfolding is a common theme underlying neurodegenerative diseases. Accordingly, most recent studies aim to prevent protein misfolding and/or aggregation as a strategy to treat these pathologies. For instance, state-of-the-art approaches, such as silencing protein overexpression by means of RNA interference, are b...

The present study builds on previous work showing that infusion of adeno-associated virus type 9 (AAV9) into the cisterna magna (CM) of non-human primates resulted in widespread transduction throughout cortex and spinal cord. Transduction efficiency was severely limited, however, by the presence of circulating anti-AAV antibodies. Accordingly, we c...

Background Liposomal drug packaging is well established as an effective means for increasing drug half-life, sustaining drug activity, and increasing drug efficacy, whether administered locally or distally to the site of disease. However, information regarding the relative effectiveness of peripheral (distal) versus local administration of liposoma...

There is considerable interest in the use of adeno-associated virus serotype 9 (AAV9) for neurological gene therapy partly because of its ability to cross the blood-brain barrier to transduce astrocytes and neurons. This raises the possibility that AAV9 might also transduce antigen-presenting cells (APC) in the brain and provoke an adaptive immune...

Niemann-Pick disease Type A (NPA) is a neuronopathic lysosomal storage disease (LSD) caused by the loss of acid sphingomyelinase (ASM). The goals of the current study are to ascertain the levels of human ASM that are efficacious in ASM knockout (ASMKO) mice, and determine whether these levels can be attained in non-human primates (NHPs) using a mul...

Niemann-Pick disease is a lysosomal storage disorder resulting from inherited deficiency in acid sphingomyelinase (ASM). Use of adeno-associated virus serotype 2 (AAV2) to deliver human acid sphingomyelinase (hASM) is currently being explored as a means to treat the devastating neurological features of NPD, which are refractory to traditional enzym...

We report the results of a long-term follow-up of subjects in a phase 1 study of AAV2-hAADC (adeno-associated virus type 2-human aromatic L-amino acid decarboxylase) gene therapy for the treatment of Parkinson's disease (PD). Ten patients with moderately advanced PD received bilateral putaminal infusions of either a low or a high dose of AAV2-hAADC...

We have previously shown that adeno-associated virus type 2 (AAV2) undergoes anterograde axonal transport in rat and non-human primate brain. We screened other AAV serotypes for axonal transport and found that AAV6 is transported almost exclusively in a retrograde direction and, in the same way as AAV2, it is also neuron-specific in rat brain. Our...

Supplementary Figure S1. GFP expression at the site of injection 3 or 6 weeks after vector delivery Coronal diagrams modified from the Paxinos and Watson atlas of the rat brain, represent the infusion coordinates used to target either the thalamus or striatum (red asterisk) demonstrate the transgene expression 3 weeks after infusion of AAV6-GFP (3...

Supplementary Figure S2. Cortical distribution from prefrontal to occipital cortex 3 weeks after AAV6 striatal injection Coronal diagrams in the left column correspond different antero-posterior levels of the rat brain as shown in the Paxinos and Watson rat atlas. Striatal infusion of AAV6-GFP resulted in a wide expression of GFP+ cell bodies found...

The mammalian target of rapamycin (mTOR) plays a central role in regulating the proliferation of cancer cells, and mTOR-specific inhibitors such as rapamycin analogs are considered as a promising therapy for malignant glioma. In this study, we investigated the possibility of using mTOR inhibitors to treat gliomas. We used a molecular marker, phosph...

Degeneration of nigrostriatal neurons in Parkinson's disease (PD) causes progressive loss of aromatic l-amino acid decarboxylase (AADC), the enzyme that converts levodopa (l-DOPA) into dopamine in the striatum. Because loss of this enzyme appears to be a major driver of progressive impairment of response to the mainstay drug, l-DOPA, one promising...

Widespread distribution of gene products at clinically relevant levels throughout the CNS has been challenging. Adeno-associated virus type 9 (AAV9) vector has been reported as a good candidate for intravascular gene delivery, but low levels of preexisting antibody titers against AAV in the blood abrogate cellular transduction within the CNS. In th...

In vivo GDNF induction from AAV2-regGDNF after 3- and 6-week of Rapamycin dosing (3 mg/kg) – results from individual striatal punches. Six individual punches (1.5 mm) were taken from each striatum. The details are described in Materials and Methods. (PDF)

Effective regulation of transgene product in anatomically circumscribed brain tissue is dependent on the pharmacokinetics of the regulating agent, the kinetics of transcriptional activation and degradation of the transgene product. We evaluated rapamycin-regulated AAV2-GDNF expression in the rat brain (striatum). Regulated (a dual-component system:...

In this review, we discuss recent developments in the delivery of adeno-associated virus-based vectors (AAV), particularly with respect to the role of axonal transport in vector distribution in the brain. The use of MRI-guidance and new stereotactic aiming devices have now established a strong foundation for neurological gene therapy to become an a...

Delivery of neurotrophic factors to treat neurodegenerative diseases has not been efficacious in clinical trials despite their known potency for promoting neuronal growth and survival. Direct gene delivery to the brain offers an approach for establishing sustained expression of neurotrophic factors but is dependent on accurate surgical procedures t...

mt is a cross-disciplinary biomedical journal devoted to publishing the most exciting advances in pharmacology and therapeutics, as they pertain to advances in translational and clinical medicine. It is recognized as one of the most prestigious journals in the field. With an impact factor of 6.825*, mt ranks in the top 4.2% of scientific journals i...

EU nano biotechnology and nano medicine conference.

Poster presentation. Translating nonhuman primate stereotactic measures to human brain targeting.

Clinical trials involving direct infusion of neurotrophic therapies for Parkinson's disease (PD) have suffered from poor coverage of the putamen. The planned use of a novel interventional-magnetic resonance imaging (iMRI) targeting system for achieving precise, real-time convection-enhanced delivery in a planned clinical trial of adeno-associated v...

Recently, we developed an MRI-based method that enables tracking of parenchymal infusions of therapeutic agents by inclusion of a contrast reagent in the infusate. We show that both liposomal Gadoteridol (GDL) and free Gadoteridol (Gd) can be used for MRI-monitored infusions into the non-human primate (NHP) putamen to predict the distribution of GD...

The number of patients worldwide who have received some kind of gene therapy is now in the thousands. A subset of that number have received intracranial injections of adeno-associated viruses encoding various therapeutic genes directed at ameliorating Parkinson's disease (PD). In this article we briefly examine the current status of Phase I and Pha...

Loss of dopaminergic neurons is primarily responsible for the onset and progression of Parkinson's disease (PD); thus, neuroprotective and/or neuroregenerative strategies remain critical to the treatment of this increasingly prevalent disease. Here we explore a novel approach to neurotrophic factor-based therapy by engineering zinc finger protein t...

Putaminal convection-enhanced delivery (CED) of an adeno-associated virus serotype 2 (AAV2) vector, containing the human aromatic L-amino acid decarboxylase (hAADC) gene for the treatment of Parkinson disease (PD), has completed a phase I clinical trial. To retrospectively analyze magnetic resonance imaging (MRI) and positron emission tomography (P...

We elucidated the effects of parkinsonian degeneration on trafficking of AAV2-GDNF in the nigro-striatum (nigro-ST) of unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. Vector infused into striatum (ST) was transported to substantia nigra (SN), both pars compacta (SNc), and pars reticulata (SNr). In the lesioned hemisphere, glial cell line-der...

Gene replacement therapy for the neurological deficits caused by lysosomal storage disorders, such as in Niemann-Pick disease type A, will require widespread expression of efficacious levels of acid sphingomyelinase (ASM) in the infant human brain. At present there is no treatment available for this devastating pediatric condition. This is partly b...

Canine spontaneous intracranial tumors bear striking similarities to their human tumor counterparts and have the potential to provide a large animal model system for more realistic validation of novel therapies typically developed in small rodent models. We used spontaneously occurring canine gliomas to investigate the use of convection-enhanced de...

This study completes the longest known in vivo monitoring of adeno-associated virus (AAV)-mediated gene expression in nonhuman primate (NHP) brain. Although six of the eight parkinsonian NHP originally on study have undergone postmortem analysis, as described previously, we monitored the remaining two animals for a total of 8 years. In this study,...

Gene therapies that utilize convention-enhanced delivery (CED) will require close monitoring of vector infusion in real time and accurate prediction of drug distribution. The magnetic resonance imaging (MRI) contrast agent, Gadoteridol (Gd), was used to monitor CED infusion and to predict the expression pattern of glial cell line-derived neurotroph...

Clinical studies to date have failed to establish therapeutic benefit of glial cell-derived neurotrophic factor (GDNF) in Parkinson's disease (PD). In contrast to previous nonclinical neuroprotective reports, this study shows clinically relevant and long-lasting regeneration of the dopaminergic system in rhesus macaques lesioned with 1-methy-4-phen...

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Combined therapy of rapamycin and nanoliposomal irinotecan (nLs-CPT-11) was used in the treatment of U87-MG intracranial brain tumor model looking for an improvement in the survival in comparison to animals that received only single-agent therapy. The prognosis for pati...

The purpose of this study was to optimize stereotactic coordinates for delivery of therapeutic agents into the thalamus and brainstem, using convection-enhanced delivery (CED) to avoid leakage into surrounding anatomical structures while maximizing CED of therapeutics within the target volume. The authors recently published targeting data for the n...

Convection-enhanced delivery (CED) of GDNF and NTN was employed to determine the tissue clearance of these factors from the rat striatum and the response of the dopaminergic system to a single infusion. Two doses of GDNF (15 and 3 microg) and NTN (10 microg and 2 microg) were infused into the rat striatum. Animals were euthanized 3, 7, 14, 21, and...

Direct delivery of therapeutic agents to the human central nervous system remains an inadequately studied field. Our group has extensively studied and refined a powerful method for distributing various macromolecules and nanoparticles into the parenchyma by means of a procedure called convection-enhanced delivery (CED). First, we developed an impro...

The stereotactic delivery of therapeutic agents into brain has been problematic because of reflux and leakage of the delivered agent. Good distribution of infusates by convection-enhanced delivery (CED) depends very much on cannula design, precise cannula placement and infusion rates. We have recently published cannula targeting data for the non-hu...

Our group has pioneered the use of gadoteridol-loaded liposomes (GDLs) in convection-enhanced delivery (CED) using real-time magnetic resonance imaging (MRI) to visualize the distribution of therapeutic agents in nonhuman primate and canine brains. We have shown that this procedure is highly predictable and safe. In the course of recent studies, ho...

We evaluated neuropathological findings in two studies of AAV2-GDNF efficacy and safety in naive aged (>20 years) or MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-lesioned rhesus macaques. In the first study, a total of 17 animals received one of two doses of AAV2-GDNF into either putamen or substantia nigra (SN). To control for surgical vari...

Optimal results in the direct brain delivery of brain therapeutics such as growth factors or viral vector into primate brain depend on reproducible distribution throughout the target region. In the present study, we retrospectively analyzed MRI of 25 convection-enhanced delivery (CED) infusions with MRI contrast into the putamen of non-human primat...

Gene therapy for brain disorders is one of the most promising frontiers in the practice of restorative neurosurgery. There are significant experimental gene therapy initiatives underway that have led to currently active clinical trials using direct intracerebral delivery of viral vectors, and these treatments have been reported as safe and well tol...

We investigated the safety and neuroregenerative potential of an adeno-associated virus (AAV2) containing human glial cell line-derived neurotrophic factor (GDNF) in an MPTP primate model of Parkinson's disease. Dopaminergic function was evaluated by positron emission tomography with 6-[(18)F]fluoro-l-m-tyrosine (FMT) before and after AAV2-GDNF or...

We used convection-enhanced delivery (CED) to characterize gene delivery mediated by adeno-associated virus type 1 (AAV1) by tracking expression of hrGFP (humanized green fluorescent protein from Renilla reniformis) into the striatum, basal forebrain, and corona radiata of monkey brain. Four cynomolgus monkeys received single infusions into corona...

Transduction of the primate cortex with adeno-associated virus (AAV)-based gene therapy vectors has been challenging, because of the large size of the cortex. We report that a single infusion of AAV2 vector into thalamus results in widespread expression of transgene in the cortex through transduction of widely dispersed thalamocortical projections....

Growth factor therapy for Parkinson's disease offers the prospect of restoration of dopaminergic innervation and/or prevention of neurodegeneration. Safety and efficacy of an adeno-associated virus (AAV2) encoding human glial cell-derived neurotrophic factor (GDNF) was investigated in aged nonhuman primates. Positron emission tomography with 6-[(18...

Adeno-associated viral (AAV) vectors are currently the preeminent gene therapy vehicles for neurological application. However, issues regarding the trafficking of AAV vectors within the primate brain, and consequently control over the targeting of transgene expression, remain a matter of investigation. Studies in nonhuman primates have shown that d...