AAV2-mediated gene transfer of GDNF to the striatum of MPTP monkeys enhances the survival and outgrowth of co-implanted fetal dopamine neurons

https://doi.org/10.1016/j.expneurol.2008.01.026Get rights and content

Abstract

Neural transplantation offers the potential of treating Parkinson's disease by grafting fetal dopamine neurons to depleted regions of the brain. However, clinical studies of neural grafting in Parkinson's disease have produced only modest improvements. One of the main reasons for this is the low survival rate of transplanted neurons. The inadequate supply of critical neurotrophic factors in the adult brain is likely to be a major cause of early cell death and restricted outgrowth of fetal grafts placed into the mature striatum. Glial derived neurotrophic factor (GDNF) is a potent neurotrophic factor that is crucial to the survival, outgrowth and maintenance of dopamine neurons, and so is a candidate for protecting grafted fetal dopamine neurons in the adult brain. We found that implantation of adeno-associated virus type 2 encoding GDNF (AAV2-GDNF) in the normal monkey caudate nucleus induced overexpression of GDNF that persisted for at least 6 months after injection. In a 6-month within-animal controlled study, AAV2-GDNF enhanced the survival of fetal dopamine neurons by 4-fold, and increased the outgrowth of grafted fetal dopamine neurons by almost 3-fold in the caudate nucleus of MPTP-treated monkeys, compared with control grafts in the other caudate nucleus. Thus, the addition of GDNF gene therapy to neural transplantation may be a useful strategy to improve treatment for Parkinson's disease.

Introduction

Neural transplantation offers the potential of treating Parkinson's disease by grafting fetal dopamine (DA) neurons to depleted regions of the host brain, providing those DA-deficient regions with a regulated source of DA. This strategy promises to provide long-term amelioration of parkinsonian signs, which available treatments are unable to achieve. Animal studies in the rodent (reviewed by Brundin et al., 1994), and in the primate (Annett, 1994, Bankiewicz et al., 1993, Elsworth et al., 1996, Fine et al., 1988, Taylor et al., 1991) have shown that grafts of fetal DA neurons can lead to reversals in biochemical and behavioral indices of DA deficiency. However, in clinical studies the improvements in Parkinsonism have been variable, and generally rather modest (Freed et al., 1992, Freed et al., 2001, Lindvall and Hagell, 2001, Olanow et al., 2003, Redmond, 2002, Spencer et al., 1992, Widner et al., 1992).

The death of the majority (∼ 90–95%) of transplanted DA neurons from the fetal ventral mesencephalon (VM) soon after grafting in rat (Brundin et al., 2000) and human (Olanow et al., 1996) can serve to limit the success of the neural transplantation treatment strategy for Parkinson's disease. An important contributor to this poor survival appears to be the environment of the adult host brain, which may be less than optimal for the survival and growth of grafted immature neurons. In particular, the inadequacy of critical growth factors in the adult brain may be a major cause of early cell death and restricted outgrowth of fetal grafts placed into the mature striatum. Thus, providing additional neurotrophic support for donor fetal neurons may reduce the problem of poor survival of neural grafts in Parkinson's disease.

Glial derived neurotrophic factor (GDNF) is a potent neurotrophic factor that is crucial to the development, survival, and outgrowth of DA neurons (Airaksinen and Saarma, 2002, Lin et al., 1993), and so it is a good candidate for protecting and maintaining grafted fetal DA neurons in the host brain. GDNF is highly expressed in the developing rat striatum, yet its concentration is relatively low in the adult brain (Choi-Lundberg and Bohn, 1995, Schaar et al., 1993, Stromberg et al., 1993). Several studies in the 6-hydroxydopamine (6-OHDA) lesioned striatum of rats have demonstrated improvements in survival and outgrowth of grafted fetal DA neurons when central injections of GDNF have been administered, or when GDNF overexpressing cells have been co-grafted to the striatum (Ahn et al., 2005, Espejo et al., 2000, Rosenblad et al., 1996, Sautter et al., 1998, Sinclair et al., 1996, Sullivan et al., 1998, Wilby et al., 1999, Yurek, 1998). These effects of GDNF on grafted VM were evaluated 1 to 8 weeks after transplantation. Gene therapy with a recombinant adeno-associated virus offers a strategy for longer-term delivery of GDNF to circumscribed regions of the brain in a relatively safe and non-invasive manner (Grieger and Samulski, 2005).

Interestingly, in the rodent, overexpression of GDNF in the intact striatum leads to an initial increase in DA turnover, followed by a selective down-regulation of TH at times longer than 6 weeks (Georgievska et al., 2004b). However, in this rat study the effect on TH was not accompanied by alteration in DA synthesis or content, indicating that the GDNF-induced changes in TH are a compensation for the initial overactivity of the DA system. Likewise in rats with a lesioned nigrostriatal DA system and intrastriatal grafts of fetal dopaminergic neurons, overexpression of GDNF results in an increase in survival of fetal dopaminergic neurons at 4 weeks, with an eventual down-regulation of TH in the grafted neurons (Georgievska et al., 2004a). Despite these rodent data with lentivirus vector delivery of GDNF, we were sufficiently encouraged by our studies with recombinant adeno-associated viral vectors (AAV) (Sondhi et al., 2005) and with GDNF-secreting macrocapsules (Redmond et al., 2002) to investigate the potential enhancement of fetal DA neuron survival and outgrowth in the striatum of MPTP-treated monkeys co-implanted with a recombinant AAV harboring the GDNF gene.

Section snippets

Materials and methods

Young adult male St. Kitts green (vervet) monkeys (Chlorocebus sabaeus) at the St. Kitts Biomedical Research Foundation (St. Kitts, West Indies) were used. As the subjects were feral monkeys, their exact ages were not known, but they were all mature with a mean weight (± standard deviation) of 6.4 ± 0.6 kg. All studies were conducted in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals, and were approved by the Institutional Animal Care and Use

Time-course of GDNF expression following AAV2-GDNF injection

The number of cells expressing GDNF in the caudate nucleus did not change significantly between 1 and 6 months after injection of AAV2-GDNF (Fig. 2). The mean number of cells (± S.E.) expressing GDNF in response to the one injection of AAV2-GDNF was 27919 ± 6158. In addition, the volume of the caudate nucleus occupied by diffuse staining for GDNF-ir did not diminish over the time period examined (Fig. 2). The mean volume occupied by elevated GDNF staining was 50 ±6 mm3.

Effect of AAV2-GDNF injection on survival and outgrowth of grafted fetal dopamine neurons

The number of surviving

Discussion

Our study of the time-course of GDNF overexpression in normal monkeys revealed that there was no decrease in expression between 1 and 6 months following injection of AAV2-GDNF in the caudate nucleus of monkeys. This outcome was in line with our expectations, based on the absence of toxicity, low immunogenicity and sustained transgene expression of AAV vectors using the chicken β-actin/cytomegalovirus (Tenenbaum et al., 2004). These results showing sustained overexpression of GDNF in normal

Acknowledgments

Jeremy Bober provided outstanding assistance in the immunohistochemical aspects of the work. We thank the staff of St. Kitts Biomedical Research Facility for their excellent contributions to the in vivo primate work. We are grateful to Xing-Hua Zeng and the Gene Therapy Center for expert assistance. The work was supported by NS44281 and NS40822.

References (58)

  • McBrideJ.L. et al.

    Neuroprotection for Parkinson's disease using viral vector-mediated delivery of GDNF

    Prog. Brain Res.

    (2002)
  • OlanowC.W. et al.

    Fetal nigral transplantation as a therapy for Parkinson's disease

    Trends Neurosci.

    (1996)
  • SautterJ. et al.

    Implants of polymer-encapsulated genetically modified cells releasing glial cell line-derived neurotrophic factor improve survival, growth, and function of fetal dopaminergic grafts

    Exp. Neurol.

    (1998)
  • StrombergI. et al.

    Glial cell line-derived neurotrophic factor is expressed in the developing but not adult striatum and stimulates developing dopamine neurons in vivo

    Exp. Neurol.

    (1993)
  • TaylorJ.R. et al.

    Severe long-term 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism in the vervet monkey (Cercopithecus aethiops sabaeus)

    Neuroscience

    (1997)
  • YurekD.M.

    Glial cell line-derived neurotrophic factor improves survival of dopaminergic neurons in transplants of fetal ventral mesencephalic tissue

    Exp. Neurol.

    (1998)
  • AiraksinenM.S. et al.

    The GDNF family: signalling, biological functions and therapeutic value

    Nat. Rev., Neurosci.

    (2002)
  • AnnettL.E.

    Functional studies of neural grafts in parkinsonian primates

  • BrundinP. et al.

    Functional effects of mesencephalic dopamine neurons and adrenal chromaffin cells grafted to the rat striatum

  • BrundinP. et al.

    Improving the survival of grafted dopaminergic neurons: a review over current approaches

    Cell Transplant

    (2000)
  • DoucetG. et al.

    Effect of prior dopamine denervation on survival and fiber outgrowth from intrastriatal fetal mesencephalic grafts

    Eur. J. Neurosci.

    (1990)
  • ElsworthJ.D. et al.

    Striatal dopaminergic correlates of stable parkinsonism and degree of recovery in old-world primates one year after MPTP treatment

    Neuroscience

    (2000)
  • EslamboliA.

    Assessment of GDNF in primate models of Parkinson's disease: comparison with human studies

    Rev. Neurosci.

    (2005)
  • EspejoM. et al.

    Increased survival of dopaminergic neurons in striatal grafts of fetal ventral mesencephalic cells exposed to neurotrophin-3 or glial cell line-derived neurotrophic factor

    Cell Transplant

    (2000)
  • FreedC.R. et al.

    Survival of implanted fetal dopamine cells and neurologic improvement 12 to 46 months after transplantation for Parkinson's disease

    N. Engl. J. Med.

    (1992)
  • FreedC.R. et al.

    Transplantation of embryonic dopamine neurons for severe Parkinson's disease

    N. Engl. J. Med.

    (2001)
  • GeorgievskaB. et al.

    Dissociation between short-term increased graft survival and long-term functional improvements in Parkinsonian rats overexpressing glial cell line-derived neurotrophic factor

    Eur. J. Neurosci.

    (2004)
  • GeorgievskaB. et al.

    Overexpression of glial cell line-derived neurotrophic factor using a lentiviral vector induces time- and dose-dependent downregulation of tyrosine hydroxylase in the intact nigrostriatal dopamine system

    J. Neurosci.

    (2004)
  • GriegerJ.C. et al.

    Adeno-associated virus as a gene therapy vector: vector development, production and clinical applications

    Adv. Biochem. Eng. Biotechnol.

    (2005)
  • Cited by (23)

    • Viral Delivery of GDNF Promotes Functional Integration of Human Stem Cell Grafts in Parkinson's Disease

      2020, Cell Stem Cell
      Citation Excerpt :

      First identified for its role in the survival and plasticity of embryonic midbrain DA neurons in culture (Lin et al., 1993), glial cell line-derived neurotrophic factor (GDNF) has been shown to increase the survival, plasticity, and metabolism of DA neurons in pre-clinical and clinical studies for PD (for reviews, see Björklund et al., 1997; Kirik et al., 2017; Thompson and Björklund, 2012). Recombinant GDNF protein has also been used to promote the survival of DA progenitors within fetal donor preparations prior to transplantation (Rosenblad et al., 1996), with studies in rodents and non-human primates demonstrating the benefits of prolonged delivery into the host tissue (via infusion) (Ahn et al., 2005; Johansson et al., 1995; Sinclair et al., 1996; Yurek, 1998) or injection of viral vectors) (Elsworth et al., 2008; Georgievska et al., 2004; Kauhausen et al., 2013; Redmond et al., 2009; Thompson et al., 2009; Wakeman et al., 2014; Winkler et al., 2006) for promoting survival, plasticity, and functionally appropriate integration of DA-rich fetal VM tissue grafts. Here, we have assessed the impact of long-term GDNF overexpression on hPSC-derived VM DA progenitor grafts.

    • Comparison of fetal mesencephalic grafts, AAV-delivered GDNF, and both combined in an MPTP-induced nonhuman primate Parkinson's model

      2013, Molecular Therapy
      Citation Excerpt :

      The recovery was often incomplete, however, and early clinical studies produced variable effects and some significant side effects, such as dyskinesia that conceivably could partially be attributed to the aberrant location of the grafts that were placed into the striatum instead of their physiological location in the SN.25 To produce more anatomic reconstruction of the DA system, we previously showed that the introduction of GDNF gene near grafted embryonic DA neurons in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys significantly increased their survival and outgrowth.15 Another study engrafted fetal VM cells into the SN and delivered GDNF into the striatum with an rAAV2/hu-GDNF vector and showed that SN grafts could reach the target areas, based upon retrograde labeling of the SN grafts with striatal injected fluorogold.26

    • Biochemical alteration in cerebrospinal fluid precedes behavioral deficits in Parkinsonian rats induced by 6-hydroxydopamine

      2009, Surgical Neurology
      Citation Excerpt :

      Continuous delivery of GDNF into the striatum by recombinant adeno-associated viral vectors protects nigrostriatal dopaminergic neurons and attenuates the behavioral deficits in common marmosets receiving intrastrital application of 6-OHDA [28]. Moreover, adenoviral delivery of the GDNF gene into the striatum safeguards nigrostriatal dopaminergic neurons against the 6-OHDA neurotoxicity in rats [8] and enhances the survival of transplanted fetal dopaminergic neurons in MPTP-treated monkeys [26]. Recent evidence also shows that long-term calcitriol treatment protects dopaminergic neurons against the neurotoxicity induced by intraventricular application of 6-OHDA [45].

    • From microsurgery to nanosurgery: how viral vectors may help repair the peripheral nerve

      2009, Progress in Brain Research
      Citation Excerpt :

      Local expression of these factors prevents the degeneration of specific sets of neurons in animal models for these diseases. Clinical trials with neurotrophic factors for these diseases are currently underway and encouraging results have been reported (Tuszynski et al., 2005; Elsworth et al., 2008). In contrast, the application of neurotrophic factors to enhance axonal regeneration has proven to be far more difficult.

    View all citing articles on Scopus
    View full text