Gene expression patterns for GDNF and its receptors in the human putamen affected by Parkinson's disease: A real-time PCR study

Bäckman, Cristina M.; Shan, Lufei; Zhang, Ya Jun; Hoffer, Barry J.; Leonard, Sherry; Troncoso, Juan C.; Vonsatel, Paul; Tomac, Andreas C.

doi:10.1016/j.mce.2006.03.013

Cited by 162 publications

(34 citation statements)

References 33 publications

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“…The physiological significance of the observed reduced binding to the related receptor, GFRα2, by GDNFv compared to GDNFwt is unknown. GFRα1, the high affinity receptor for GDNF, is expressed in dopaminergic neurons in the putamen, the targeted region of the brain for GDNF therapy (Bäckman et al, 2007;Kozlowski et al, 2004). GFRα2, however, does not appear to be expressed in the rat striatum (Kozlowski et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Increased brain bio-distribution and chemical stability and decreased immunogenicity of an engineered variant of GDNF

Smith

O’Bryan

Mitchell

et al. 2015

Experimental Neurology

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Several lines of evidence indicate that Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for dopaminergic neurons. Direct parenchymal administration of GDNF is robustly neuroprotective and neurorestorative in multiple neurotoxin-based animal models (rat and non-human primate (NHP)) of Parkinson's Disease (PD), suggesting its potential as a therapeutic agent. Although small, open-label clinical trials of intra-putamenal administration of bacteria-derived, full length, wild type GDNF (GDNFwt) were efficacious in improving standardized behavioral scores, a double-blinded, randomized controlled trial failed to do so. We hypothesize that the lack of clinical efficacy of GDNFwt in the larger randomized trial was due to poor bio-distribution in the putamen and/or poor chemical stability while in the delivery device for prolonged time periods at 37°C. The development of neutralizing antibodies in some patients may also have been a contributing factor. GDNFv is an engineered form of GDNFwt, expressed and purified from mammalian cells, designed to overcome these limitations, including removal of the N-terminal heparin-binding domain to improve its diffusivity in brain parenchyma by reducing its binding to extracellular matrix (ECM), and key amino acid substitutions to improve chemical stability. Intra-striatal administration of a single injection of GDNFv in the rat produced significantly greater brain distribution than GDNFwt, consistent with reduced binding to ECM. Using liquid chromatography/mass spectrometry (LS/MS) methods GDNFv was shown to have improved chemical stability compared to GDNFwt when stored at 37°C for 4weeks. In addition, GDNFv resulted in lower predicted clinical immunogenicity compared to GDNFwt, as demonstrated by reduced CD4+ T cell proliferation and reduced IL-2-induced secretion in peripheral blood mononucleated cells collected from volunteers representing the world's major histocompatibility complex (MHC) haplotypes. GDNFv was demonstrated to be pharmacologically equivalent to GDNFwt in the key parameters in vitro of GFRα1 receptor binding, c-Ret phosphorylation, neurite outgrowth, and in vivo in its ability to increase dopamine turnover (DA). GDNFv protected dopamine nerve terminals and neurons in a 6-hydroxy-dopamine (6-OHDA) rat model. In summary, we empirically demonstrate the superior properties of GDNFv compared to GDNFwt through enhanced bio-distribution and chemical stability concurrently with decreased predicted clinical immunogenicity while maintaining pharmacological and neurotrophic activity. These data indicate that GDNFv is an improved version of GDNF suitable for clinical assessment as a targeted regenerative therapy for PD.

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Section: Discussionmentioning

confidence: 99%

Increased brain bio-distribution and chemical stability and decreased immunogenicity of an engineered variant of GDNF

Smith

O’Bryan

Mitchell

et al. 2015

Experimental Neurology

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“…However, using immunohistochemistry, large reductions in GDNF content are reported in surviving PD substantia nigra neurons (Chauhan et al, 2001). More recently, using real-time PCR, modest but significantly increased levels of a GDNF isoform were found in the putamen of PD patients with marked nigral neuronal loss (Backman et al, 2006). Whatever might be the endogenous changes of neurotrophic factors in PD, a therapy with GDNF might prevent the progression of the disease and restore function (Gill et al, 2003;Slevin et al, 2005).…”

Section: Gdnf Expression Upon Nigrostriatal Injury: Role Of Neuronglimentioning

confidence: 99%

“…Since GDNF expression is reduced in the adult brain, the use of techniques that enhance the detection of low copy mRNA transcripts may be crucial for accurate quantification of its expression. Recently, using real-time PCR, Backman et al (2006) described the GDNF isoform II as the predominant transcript in the putamen of human subjects, whereas only the expression of GDNF isoform I is modestly increased in the putamen of PD patients with marked nigral neuronal loss (Backman et al, 2006).…”

Section: Introduction: the Relevance Of Studying The Endogenous Gdnf mentioning

confidence: 99%

Driving GDNF expression: The green and the red traffic lights

Saavedra

Baltazar

Duarte

2008

Progress in Neurobiology

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“…For example, the transcript level of one of the most commonly used reference genes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), has been shown to vary considerably under different experimental conditions (Zhong and Simons, 1999;Glare et al, 2002;Aerts et al, 2004;Bas et al, 2004), rendering it unsuitable for normalization in those studies. However, other groups have found the expression of GAPDH to be stable (Ullmannová and Haškovec, 2003;Bäckman et al, 2006;Meldgaard et al, 2006), thus highlighting the importance of evaluating the stability of a chosen reference gene for each new experimental condition (Dheda et al, 2004;Wong and Medrano, 2005a;Meldgaard et al, 2006).…”

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confidence: 99%

Validation of reference genes for normalization of real‐time quantitative RT‐PCR data in traumatic brain injury

Cook

Vink

Donkin

et al. 2008

J of Neuroscience Research

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Careful validation of reference genes used for the normalization of real-time RT-PCR data is required to obtain accurate results regarding gene expression. We evaluated the stability of seven commonly used reference genes in the cerebral cortex and hippocampus of rats 3 days following traumatic brain injury (TBI). HPRT, SDHA, and GUSB were found to be the most stable reference genes in the cerebral cortex, whereas B2MG, TBP, and GAPDH were the most stable in the hippocampus. The use of three reference genes was determined to be the optimal number for accurate normalization of data. To illustrate this point, when our gene of interest, substance P (SP), was normalized against the three most stable reference genes in both brain areas, we found no significant difference between injured and uninjured rats at the 3-day time point. However, when our SP data were normalized to each reference gene individually, SP mRNA level was highly variable depending on the reference gene chosen. The results of the present study highlight the importance of validating reference genes to be used for real-time RT-PCR analysis. The use of the most stable reference genes presented here will allow more accurate normalization of gene expression data in TBI.

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Gene expression patterns for GDNF and its receptors in the human putamen affected by Parkinson's disease: A real-time PCR study

Cited by 162 publications

References 33 publications

Increased brain bio-distribution and chemical stability and decreased immunogenicity of an engineered variant of GDNF

Increased brain bio-distribution and chemical stability and decreased immunogenicity of an engineered variant of GDNF

Driving GDNF expression: The green and the red traffic lights

Validation of reference genes for normalization of real‐time quantitative RT‐PCR data in traumatic brain injury

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