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Astrocytes as Cellular Vehicles in Ex Vivo Gene Therapy Studies to the Rat Brain

Ericson, Cecilia LU (2005)
Abstract
Neurodegenerative disorders are characterized by a progressive cell-death in the brain, and loss of different functions in the patient. Today, there are no cures for any of the various diseases. Parkinson's disease is a neurodegenerative disorder with a prevalence of 0.1% and the first symptoms usually start to appear between 50-60 years of age with rigidity, tremor, bradykinesia and postural abnormalities. Even though the reason for the development is not fully understood, the pathophysiology of the disease has been well documented. ?Sere is a progressive loss of dopamine-producing cells in substantia nigra in the midbrain, resulting in a significant decline of dopamine levels in the striatum and a disturbed motoric function. ?Se most... (More)
Neurodegenerative disorders are characterized by a progressive cell-death in the brain, and loss of different functions in the patient. Today, there are no cures for any of the various diseases. Parkinson's disease is a neurodegenerative disorder with a prevalence of 0.1% and the first symptoms usually start to appear between 50-60 years of age with rigidity, tremor, bradykinesia and postural abnormalities. Even though the reason for the development is not fully understood, the pathophysiology of the disease has been well documented. ?Sere is a progressive loss of dopamine-producing cells in substantia nigra in the midbrain, resulting in a significant decline of dopamine levels in the striatum and a disturbed motoric function. ?Se most common treatment today is oral intake of levodopa, the rate-limiting enzyme in the dopamine synthesis pathway, however the effects of the drug becomes limited over time and hence, there is a need for alternative therapy. Instead of using fetal human tissue for transplantation, with both logistical and ethical dilemmas, ex vivo gene therapy holds great promise for treatment of different neurodegenerative disorders. Ex vivo gene therapy is a combination of cell transplantation and genetic engineering, with the aim of restoring lost neurotransmitters, such as dopamine, or to transfer neurotrophic factors to stimulate cell survival in a damaged or injured brain. In the present thesis, I have genetically modified primary astrocytes of both rodent and human origin with lentiviral vectors in order to evaluate the potential of the cells to provide long-term transgene expression following transplantation to the rat brain. Astrocytes are a type of glial cells in the brain attributed various functions, and have been explored in several studies to be used as cellular vehicles in ex vivo gene delivery to the central nervous system. Compared to previous studies were astrocytes have been genetically modified in vitro using other viralbased vectors, I have shown in my work that lentivirally transduced astrocytes have the capacity to express the transgene product at significant levels for up to at least 12 weeks after grafting to the rat brain. However, before moving towards clinical trials using genetically modified astrocytes, the vector system has to be further developed in order to be able to regulate the transgene expression, even after the cells have been integrated within the host brain. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Neurodegenerativa sjukdomar karaktäriseras av långsam celldöd i hjärnan med en gradvis försämring av olika funktioner hos patienten. Ytterligare en gemensam nämnare är att de idag inte går att bota. En av dessa är Parkinsons sjukdom, som drabbar ungefär 0.1% av befolkningen, och inträder oftast i femtio- till sextioårsåldern med minskad rörlighet och muskelstelhet som mest framträdande symptom. Varför sjukdomen uppkommer är till stor del okänt, men man vet att de dopamin-producerande cellerna i mellanhjärnan (substantia nigra) dör, med dopaminförlust i hjärnans motoriska centrum (striatum) som konsekvens. De mediciner som finns idag fungerar bra under de första 5-10 åren, men därefter uppvisar... (More)
Popular Abstract in Swedish

Neurodegenerativa sjukdomar karaktäriseras av långsam celldöd i hjärnan med en gradvis försämring av olika funktioner hos patienten. Ytterligare en gemensam nämnare är att de idag inte går att bota. En av dessa är Parkinsons sjukdom, som drabbar ungefär 0.1% av befolkningen, och inträder oftast i femtio- till sextioårsåldern med minskad rörlighet och muskelstelhet som mest framträdande symptom. Varför sjukdomen uppkommer är till stor del okänt, men man vet att de dopamin-producerande cellerna i mellanhjärnan (substantia nigra) dör, med dopaminförlust i hjärnans motoriska centrum (striatum) som konsekvens. De mediciner som finns idag fungerar bra under de första 5-10 åren, men därefter uppvisar den största delen av patienterna kraftiga svängningar i motorisk funktion med svårkontrollerade, ofrivilliga rörelser. Därför finns det ett stort behov av att hitta andra behandlingsformer för att lindra besvär och fördröja sjukdomsförloppet. Transplantation av dopaminproducerande vävnad från aborterade humana foster som alternativ behandlingsmetod har utförts i drygt tjugo år och givit positiva resultat. Det finns dock uppenbara problem, såsom tillgång till material samt etiska aspekter, vilket därför gör att man ihärdigt utforskar andra typer av celler. Hjärnan består i huvudsak av två celltyper: Nerv- och gliaceller. Gliacellen har länge ansetts bara fungera som en slags stödjecell till nervcellen med funktioner såsom att hantera tillförseln av näring (syre och glukos) från kapillär till nervcell, men idag vet man att deras existens är avgörande för nervcellens utveckling och hjärnans överlevnad. Astrocyter är en typ av gliaceller som visat sig ha goda överlevnadsegenskaper i samband med transplantation av dessa. I mitt avhandlingsarbete har jag jobbat med ex vivo genterapi, som innebär att man tar celler från en individ (djur eller människa), modifierar dem genetiskt, och därefter transplanterar dem till en mottagare. I mina arbeten har jag odlat astrocyter från embryonala mus-, rått- eller humanhjärnor, genmodifierat dem med hjälp av ett HIV-baserat virus (s.k. lentivirala vektorer) för att få dem att fungera som bärare och producenter av olika proteiner. Proteinerna i sin tur, beroende på typ och målsättning, verkar på en mängd olika sätt i hjärnan. Exempel på detta kan vara alltifrån att stimulera nervcellsöverlevnad (vid skada eller sjukdom, såsom Parkinsons sjukdom) till att endast uttrycka ett grönfluorescerande markörprotein i studiesyfte (som på omslaget till denna avhandling). Till skillnad från tidigare astrocytrelaterade studier, där man använt sig av andra virusbaserade vektorer för överföring av gener, har jag i denna avhandling visat att de lentivirusmodifierade astrocyterna har förmågan att efter transplantation uttrycka det nya proteinet i höga nivåer under längre tid. Innan genetiskt modifierade humana astrocyter kan appliceras för transplantation i kliniska försök, krävs det dock en vidareutveckling av vektor-systemet för att kunna erhålla en bestående effekt, samt reglera nivåerna av det terapeutiska proteinet efter transplantation till hjärnan. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr Barker, Roger, University of Cambridge, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Medicin (människa och djur), Medicine (human and vertebrates), Lentivirus, Transplantation, CNS, Astrocytes
pages
142 pages
publisher
Grahns Tryckeri AB, Lund
defense location
Segerfalksalen, Wallenberg Neurocentrum. Lund
defense date
2005-04-16 09:15:00
ISBN
91-85439-17-7
language
English
LU publication?
yes
additional info
Cecilia Eriksson, Cecilia Ericson, Monte A. Gates and Klas Wictorin. 2000. Long-term, EGF-stimulated cultures of attached GFAP-positive cells derived from the embryonic mouse lateral ganglionic eminence: in vitro and transplantation studies. Exp Neurol., vol 164 pp 184-99.
Ulrica Englund, Cecilia Ericson, Carl Rosenblad, Ron J. Mandel, Didier Trono, Anders Björklund, Klas Wictorin and Cecilia Lundberg. 2000. The use of a recombinant lentiviral vector for ex vivo gene transfer into the rat CNS. NeuroReport, vol 11 pp 3973-7.
Cecilia Ericson, Klas Wictorin and Cecilia Lundberg. 2002. Ex vivo and in vitro studies of transgene expression in rat astrocytes transduced with lentiviral vectors. Exp Neurol., vol 173 pp 22-30.
Cecilia Ericson, Biljana Georgievska* and Cecilia Lundberg*. . Long-term ex vivo gene delivery of GDNF using primary astrocytes transduced with a lentiviral vector provides neuroprotection in a rat model of Parkinson’s disease. (submitted)
Cecilia Ericson, Nina Rosenqvist, Marie Jönsson, Bengt Juliusson, Philip Kusk, Teit E. Johansen and Cecilia Lundberg. . Ex vivo gene delivery to the rat brain using human astrocytes transduced with a lentiviral vector. (manuscript)
id
7ed620b0-6fd6-4426-8adc-2d69b7db6283 (old id 544595)
date added to LUP
2016-04-01 16:38:43
date last changed
2018-11-21 20:43:00
@phdthesis{7ed620b0-6fd6-4426-8adc-2d69b7db6283,
  abstract     = {{Neurodegenerative disorders are characterized by a progressive cell-death in the brain, and loss of different functions in the patient. Today, there are no cures for any of the various diseases. Parkinson's disease is a neurodegenerative disorder with a prevalence of 0.1% and the first symptoms usually start to appear between 50-60 years of age with rigidity, tremor, bradykinesia and postural abnormalities. Even though the reason for the development is not fully understood, the pathophysiology of the disease has been well documented. ?Sere is a progressive loss of dopamine-producing cells in substantia nigra in the midbrain, resulting in a significant decline of dopamine levels in the striatum and a disturbed motoric function. ?Se most common treatment today is oral intake of levodopa, the rate-limiting enzyme in the dopamine synthesis pathway, however the effects of the drug becomes limited over time and hence, there is a need for alternative therapy. Instead of using fetal human tissue for transplantation, with both logistical and ethical dilemmas, ex vivo gene therapy holds great promise for treatment of different neurodegenerative disorders. Ex vivo gene therapy is a combination of cell transplantation and genetic engineering, with the aim of restoring lost neurotransmitters, such as dopamine, or to transfer neurotrophic factors to stimulate cell survival in a damaged or injured brain. In the present thesis, I have genetically modified primary astrocytes of both rodent and human origin with lentiviral vectors in order to evaluate the potential of the cells to provide long-term transgene expression following transplantation to the rat brain. Astrocytes are a type of glial cells in the brain attributed various functions, and have been explored in several studies to be used as cellular vehicles in ex vivo gene delivery to the central nervous system. Compared to previous studies were astrocytes have been genetically modified in vitro using other viralbased vectors, I have shown in my work that lentivirally transduced astrocytes have the capacity to express the transgene product at significant levels for up to at least 12 weeks after grafting to the rat brain. However, before moving towards clinical trials using genetically modified astrocytes, the vector system has to be further developed in order to be able to regulate the transgene expression, even after the cells have been integrated within the host brain.}},
  author       = {{Ericson, Cecilia}},
  isbn         = {{91-85439-17-7}},
  keywords     = {{Medicin (människa och djur); Medicine (human and vertebrates); Lentivirus; Transplantation; CNS; Astrocytes}},
  language     = {{eng}},
  publisher    = {{Grahns Tryckeri AB, Lund}},
  school       = {{Lund University}},
  title        = {{Astrocytes as Cellular Vehicles in Ex Vivo Gene Therapy Studies to the Rat Brain}},
  year         = {{2005}},
}