GDNF and Neurturin isoforms in an experimental model of Parkinson's disease

Anna-Maija Katariina Penttinen

Forskningsoutput: AvhandlingDoktorsavhandlingSamling av artiklar

Sammanfattning

Parkinson’s disease (PD) is a neurodegenerative disease characterized by intracellular proteinaceous inclusions called Lewy bodies and progressive loss of dopaminergic neurons in the substantia nigra (SN). The first symptoms of PD are non-motor, such as hyposmia and gastrointestinal disturbances, followed by motor symptoms, such as tremor and rigidity. Currently available therapies, medication, surgical procedures and supportive therapies, are symptomatic and do not affect the underlying cause of the disease — the neuronal degeneration. Thus, a new therapy which would restore the dopaminergic phenotype of dying neurons and thus slow down or even halt the progress of the disease is needed. Neurotrophic factors are secretory proteins regulating survival and functioning of the neurons as well as the formation of new neuronal contacts. Neurotrophic factors have shown great potential in animal models of PD, but in clinical trials, the results have been contradictory. One possible explanation for this is poor diffusion and bioavailability of the therapeutic proteins in the target tissue. The aim of this study was to explore the neuroprotective effects of the isoforms of two of the most potent dopamine neurotrophic factors, GDNF (glial cell line-derived neurotrophic factor) and its homolog neurturin (NRTN) in an experimental model of PD, and to characterize a new stable low-dose 6-hydroxydopamine (6-OHDA) rat PD model. In the PD model the degeneration of the nigrostriatal pathway was induced by administrating toxic dopamine analog 6-OHDA into the striatum, where the nerve terminals of the dopaminergic neurons are located. We compared several different administration paradigms to find the optimal parameters to induce a stable lesion model with high success rate. The cell loss induced with low doses (6-9 µg) of 6-OHDA was at similar level as the cell loss induced with higher (20 µg) doses of 6-OHDA. The advantage of using low 6-OHDA doses is the avoidance of non-specific damage, which occurs with higher 6-OHDA doses. Moreover, the low-dose induced lesions have high success rate, reducing the number of animals needed in the experiments and increasing the reliability of the obtained results. The spreading of NRTN in the brain tissue was improved by modifying the extracellular matrix binding sequence of the protein. New NRTN variants were biologically active and were able to initiate signaling via tyrosine kinase Ret (rearranged during transfection). In the neuroprotection assay in rat 6-OHDA model of PD NRTN variant N4 protected the dopaminergic neurons in the SN and fibers in the striatum as well as improved the motor behavior of the animals. In neurorestoration assay, N4 showed a trend in improving the behavioral deficits of the animals. GDNF, on the other hand, was administered to the brain with viral vectors, enabling long-term protein expression in the target tissue. GDNF has been widely studied, but the research has focused on the full-length constitutively secreted α-isoform, whereas the biology of the shorter and activity-dependently secreted β-GDNF has not been studied in vivo before. In the non-lesioned striatum, both isoforms increased striatal dopamine transporter-immunoreactivity. Both isoforms also protected the dopaminergic neurons in SN from 6-OHDA-induced degeneration. The results show that these new and less studied neurotrophic factor isoforms are able to slow down the degeneration of the midbrain dopaminergic neurons. In other words, both NRTN variant N4 and β-GDNF are potential disease-modifying factors for PD.
Originalspråkengelska
Tilldelande institution
  • Helsingfors universitet
Handledare
  • Airavaara, Mikko, Handledare
  • Tuominen, Raimo K., Handledare
Tilldelningsdatum23 sep 2017
UtgivningsortUniversity of Helsinki
Tryckta ISBN978-951-51-3633-6
Elektroniska ISBN978-951-51-3634-3
StatusPublicerad - 23 sep 2017
MoE-publikationstypG5 Doktorsavhandling (artikel)

Vetenskapsgrenar

  • 1182 Biokemi, cell- och molekylärbiologi
  • 1184 Genetik, utvecklingsbiologi, fysiologi
  • 3112 Neurovetenskaper

Citera det här

Penttinen, A-M. K. (2017). GDNF and Neurturin isoforms in an experimental model of Parkinson's disease. University of Helsinki.
Penttinen, Anna-Maija Katariina. / GDNF and Neurturin isoforms in an experimental model of Parkinson's disease. University of Helsinki, 2017. 152 s.
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title = "GDNF and Neurturin isoforms in an experimental model of Parkinson's disease",
abstract = "Parkinson’s disease (PD) is a neurodegenerative disease characterized by intracellular proteinaceous inclusions called Lewy bodies and progressive loss of dopaminergic neurons in the substantia nigra (SN). The first symptoms of PD are non-motor, such as hyposmia and gastrointestinal disturbances, followed by motor symptoms, such as tremor and rigidity. Currently available therapies, medication, surgical procedures and supportive therapies, are symptomatic and do not affect the underlying cause of the disease — the neuronal degeneration. Thus, a new therapy which would restore the dopaminergic phenotype of dying neurons and thus slow down or even halt the progress of the disease is needed. Neurotrophic factors are secretory proteins regulating survival and functioning of the neurons as well as the formation of new neuronal contacts. Neurotrophic factors have shown great potential in animal models of PD, but in clinical trials, the results have been contradictory. One possible explanation for this is poor diffusion and bioavailability of the therapeutic proteins in the target tissue. The aim of this study was to explore the neuroprotective effects of the isoforms of two of the most potent dopamine neurotrophic factors, GDNF (glial cell line-derived neurotrophic factor) and its homolog neurturin (NRTN) in an experimental model of PD, and to characterize a new stable low-dose 6-hydroxydopamine (6-OHDA) rat PD model. In the PD model the degeneration of the nigrostriatal pathway was induced by administrating toxic dopamine analog 6-OHDA into the striatum, where the nerve terminals of the dopaminergic neurons are located. We compared several different administration paradigms to find the optimal parameters to induce a stable lesion model with high success rate. The cell loss induced with low doses (6-9 µg) of 6-OHDA was at similar level as the cell loss induced with higher (20 µg) doses of 6-OHDA. The advantage of using low 6-OHDA doses is the avoidance of non-specific damage, which occurs with higher 6-OHDA doses. Moreover, the low-dose induced lesions have high success rate, reducing the number of animals needed in the experiments and increasing the reliability of the obtained results. The spreading of NRTN in the brain tissue was improved by modifying the extracellular matrix binding sequence of the protein. New NRTN variants were biologically active and were able to initiate signaling via tyrosine kinase Ret (rearranged during transfection). In the neuroprotection assay in rat 6-OHDA model of PD NRTN variant N4 protected the dopaminergic neurons in the SN and fibers in the striatum as well as improved the motor behavior of the animals. In neurorestoration assay, N4 showed a trend in improving the behavioral deficits of the animals. GDNF, on the other hand, was administered to the brain with viral vectors, enabling long-term protein expression in the target tissue. GDNF has been widely studied, but the research has focused on the full-length constitutively secreted α-isoform, whereas the biology of the shorter and activity-dependently secreted β-GDNF has not been studied in vivo before. In the non-lesioned striatum, both isoforms increased striatal dopamine transporter-immunoreactivity. Both isoforms also protected the dopaminergic neurons in SN from 6-OHDA-induced degeneration. The results show that these new and less studied neurotrophic factor isoforms are able to slow down the degeneration of the midbrain dopaminergic neurons. In other words, both NRTN variant N4 and β-GDNF are potential disease-modifying factors for PD.",
keywords = "1182 Biochemistry, cell and molecular biology, 1184 Genetics, developmental biology, physiology, 3112 Neurosciences",
author = "Penttinen, {Anna-Maija Katariina}",
year = "2017",
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day = "23",
language = "English",
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series = "Dissertationes Scholae Doctoralis Ad Sanitatem Investigandam Universitatis Helsinkiensis",
publisher = "University of Helsinki",
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Penttinen, A-MK 2017, 'GDNF and Neurturin isoforms in an experimental model of Parkinson's disease', Helsingfors universitet, University of Helsinki.

GDNF and Neurturin isoforms in an experimental model of Parkinson's disease. / Penttinen, Anna-Maija Katariina.

University of Helsinki, 2017. 152 s.

Forskningsoutput: AvhandlingDoktorsavhandlingSamling av artiklar

TY - THES

T1 - GDNF and Neurturin isoforms in an experimental model of Parkinson's disease

AU - Penttinen, Anna-Maija Katariina

PY - 2017/9/23

Y1 - 2017/9/23

N2 - Parkinson’s disease (PD) is a neurodegenerative disease characterized by intracellular proteinaceous inclusions called Lewy bodies and progressive loss of dopaminergic neurons in the substantia nigra (SN). The first symptoms of PD are non-motor, such as hyposmia and gastrointestinal disturbances, followed by motor symptoms, such as tremor and rigidity. Currently available therapies, medication, surgical procedures and supportive therapies, are symptomatic and do not affect the underlying cause of the disease — the neuronal degeneration. Thus, a new therapy which would restore the dopaminergic phenotype of dying neurons and thus slow down or even halt the progress of the disease is needed. Neurotrophic factors are secretory proteins regulating survival and functioning of the neurons as well as the formation of new neuronal contacts. Neurotrophic factors have shown great potential in animal models of PD, but in clinical trials, the results have been contradictory. One possible explanation for this is poor diffusion and bioavailability of the therapeutic proteins in the target tissue. The aim of this study was to explore the neuroprotective effects of the isoforms of two of the most potent dopamine neurotrophic factors, GDNF (glial cell line-derived neurotrophic factor) and its homolog neurturin (NRTN) in an experimental model of PD, and to characterize a new stable low-dose 6-hydroxydopamine (6-OHDA) rat PD model. In the PD model the degeneration of the nigrostriatal pathway was induced by administrating toxic dopamine analog 6-OHDA into the striatum, where the nerve terminals of the dopaminergic neurons are located. We compared several different administration paradigms to find the optimal parameters to induce a stable lesion model with high success rate. The cell loss induced with low doses (6-9 µg) of 6-OHDA was at similar level as the cell loss induced with higher (20 µg) doses of 6-OHDA. The advantage of using low 6-OHDA doses is the avoidance of non-specific damage, which occurs with higher 6-OHDA doses. Moreover, the low-dose induced lesions have high success rate, reducing the number of animals needed in the experiments and increasing the reliability of the obtained results. The spreading of NRTN in the brain tissue was improved by modifying the extracellular matrix binding sequence of the protein. New NRTN variants were biologically active and were able to initiate signaling via tyrosine kinase Ret (rearranged during transfection). In the neuroprotection assay in rat 6-OHDA model of PD NRTN variant N4 protected the dopaminergic neurons in the SN and fibers in the striatum as well as improved the motor behavior of the animals. In neurorestoration assay, N4 showed a trend in improving the behavioral deficits of the animals. GDNF, on the other hand, was administered to the brain with viral vectors, enabling long-term protein expression in the target tissue. GDNF has been widely studied, but the research has focused on the full-length constitutively secreted α-isoform, whereas the biology of the shorter and activity-dependently secreted β-GDNF has not been studied in vivo before. In the non-lesioned striatum, both isoforms increased striatal dopamine transporter-immunoreactivity. Both isoforms also protected the dopaminergic neurons in SN from 6-OHDA-induced degeneration. The results show that these new and less studied neurotrophic factor isoforms are able to slow down the degeneration of the midbrain dopaminergic neurons. In other words, both NRTN variant N4 and β-GDNF are potential disease-modifying factors for PD.

AB - Parkinson’s disease (PD) is a neurodegenerative disease characterized by intracellular proteinaceous inclusions called Lewy bodies and progressive loss of dopaminergic neurons in the substantia nigra (SN). The first symptoms of PD are non-motor, such as hyposmia and gastrointestinal disturbances, followed by motor symptoms, such as tremor and rigidity. Currently available therapies, medication, surgical procedures and supportive therapies, are symptomatic and do not affect the underlying cause of the disease — the neuronal degeneration. Thus, a new therapy which would restore the dopaminergic phenotype of dying neurons and thus slow down or even halt the progress of the disease is needed. Neurotrophic factors are secretory proteins regulating survival and functioning of the neurons as well as the formation of new neuronal contacts. Neurotrophic factors have shown great potential in animal models of PD, but in clinical trials, the results have been contradictory. One possible explanation for this is poor diffusion and bioavailability of the therapeutic proteins in the target tissue. The aim of this study was to explore the neuroprotective effects of the isoforms of two of the most potent dopamine neurotrophic factors, GDNF (glial cell line-derived neurotrophic factor) and its homolog neurturin (NRTN) in an experimental model of PD, and to characterize a new stable low-dose 6-hydroxydopamine (6-OHDA) rat PD model. In the PD model the degeneration of the nigrostriatal pathway was induced by administrating toxic dopamine analog 6-OHDA into the striatum, where the nerve terminals of the dopaminergic neurons are located. We compared several different administration paradigms to find the optimal parameters to induce a stable lesion model with high success rate. The cell loss induced with low doses (6-9 µg) of 6-OHDA was at similar level as the cell loss induced with higher (20 µg) doses of 6-OHDA. The advantage of using low 6-OHDA doses is the avoidance of non-specific damage, which occurs with higher 6-OHDA doses. Moreover, the low-dose induced lesions have high success rate, reducing the number of animals needed in the experiments and increasing the reliability of the obtained results. The spreading of NRTN in the brain tissue was improved by modifying the extracellular matrix binding sequence of the protein. New NRTN variants were biologically active and were able to initiate signaling via tyrosine kinase Ret (rearranged during transfection). In the neuroprotection assay in rat 6-OHDA model of PD NRTN variant N4 protected the dopaminergic neurons in the SN and fibers in the striatum as well as improved the motor behavior of the animals. In neurorestoration assay, N4 showed a trend in improving the behavioral deficits of the animals. GDNF, on the other hand, was administered to the brain with viral vectors, enabling long-term protein expression in the target tissue. GDNF has been widely studied, but the research has focused on the full-length constitutively secreted α-isoform, whereas the biology of the shorter and activity-dependently secreted β-GDNF has not been studied in vivo before. In the non-lesioned striatum, both isoforms increased striatal dopamine transporter-immunoreactivity. Both isoforms also protected the dopaminergic neurons in SN from 6-OHDA-induced degeneration. The results show that these new and less studied neurotrophic factor isoforms are able to slow down the degeneration of the midbrain dopaminergic neurons. In other words, both NRTN variant N4 and β-GDNF are potential disease-modifying factors for PD.

KW - 1182 Biochemistry, cell and molecular biology

KW - 1184 Genetics, developmental biology, physiology

KW - 3112 Neurosciences

M3 - Doctoral Thesis

SN - 978-951-51-3633-6

T3 - Dissertationes Scholae Doctoralis Ad Sanitatem Investigandam Universitatis Helsinkiensis

CY - University of Helsinki

ER -

Penttinen A-MK. GDNF and Neurturin isoforms in an experimental model of Parkinson's disease. University of Helsinki, 2017. 152 s. (Dissertationes Scholae Doctoralis Ad Sanitatem Investigandam Universitatis Helsinkiensis; 50/2017 ).