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Oligodendroglial (dys)function in alpha-synucleinopathies

Azevedo, Carla LU (2020) In Lund University, Faculty of Medicine Doctoral Dissertation Series
Abstract
The complexity of a-synucleinopathies, which include multiple system atrophy (MSA) and Parkinson’s disease (PD), is not entirely understood. It is known that pathological accumulation of a-synuclein (a-syn) into proteinaceous aggregates is a cellular hallmark of these diseases. a-Syn positive aggregates appear in neurons in PD and dementia with Lewy bodies (DLB), and in oligodendrocytes in MSA. Much research has focused on using animal models that pathocopy and phenocopy PD and MSA to investigate the disease pathogenesis. However, as no genetic link has been associated with MSA, it is possible that current transgenic models do not fully reflect the human pathology. The discovery of induced pluripotent stem cells (iPSCs) changed life... (More)
The complexity of a-synucleinopathies, which include multiple system atrophy (MSA) and Parkinson’s disease (PD), is not entirely understood. It is known that pathological accumulation of a-synuclein (a-syn) into proteinaceous aggregates is a cellular hallmark of these diseases. a-Syn positive aggregates appear in neurons in PD and dementia with Lewy bodies (DLB), and in oligodendrocytes in MSA. Much research has focused on using animal models that pathocopy and phenocopy PD and MSA to investigate the disease pathogenesis. However, as no genetic link has been associated with MSA, it is possible that current transgenic models do not fully reflect the human pathology. The discovery of induced pluripotent stem cells (iPSCs) changed life science, and allowed for the first time to conduct large scale experimental work using patient cells. Since these cells are embryonic pluripotentlike, their use can help to unravel early disease mechanisms, as they can be differentiated into young brain cells.
Despite intense research efforts made to understand the pathogenesis of PD and MSA, several questions remain unanswered, in particular the origin of a-syn in oligodendrocytes and possible toxicity to these cells.
The work presented in this thesis aims to 1) generate patient iPSC- based models, 2) develop efficient protocols to generate dopaminergic neurons and oligodendrocytes from iPSCs, and 3) study the role of oligodendrocytes in synucleinopathies, to gain insights into oligodendrocyte (dys)function in PD and MSA. Here, we report that during
oligodendrocyte development and in the human brain, the SNCA gene encoding for a-syn is differentially expressed in oligodendrocytes. Since neurons expressing pathogenic forms of a-syn exhibit cellular alterations, we hypothesized that oligodendrocytes having the same genetic background should also be affected.
For the first time, we show that iPSC-derived oligodendrocytes generated from PD patients carrying the variation p.A53T in a-syn or a triplication of the SNCA locus, and from MSA patients, display impaired differentiation and maturation. This was further supported by observations from experiments involving mouse embryonic stem cell
(mESC)-derived oligodendrocytes generated from the M83 transgenic mouse model of PD. Moreover, we demonstrate that p.A53T a-syn and MSA oligodendrocytes exhibit a deviation in their phenotype, adopting an immune-reactive phenotype and not myelinating oligodendroglia. Finally, our transcriptomic data further reveal
alterations in innate inflammatory components, with differential expression of complement proteins, MHC-class and immune-proteasome genes in p.A53T a-syn and MSA oligodendrocytes.
This thesis is composed of a unique set of studies addressing crucial questions related to the origin of a-syn in oligodendroglia, and focuses on elucidating the cellular alterations in oligodendrocytes in PD and MSA. (Less)
Abstract (Swedish)
Komplexiteten hos a-synukleinopatier, som inkluderar multipel systematrofi (MSA) och Parkinsons sjukdom (PS), är inte helt klarlagd. Det är känt att patologisk ansamling av a-synuclein (a-syn) till fiberlika proteinaggregat är ett cellulärt kännetecken för dessa sjukdomar. a-Syn-positiva aggregat förekommer i nervceller i PS och Lewy body demens (LBD) och i oligodendrocyter i MSA. Mycket forskning har fokuserat på att använda djurmodeller som patokopierar och fenokopierar PS och MSA för att undersöka sjukdomsförloppet. Eftersom ingen genetisk koppling har associerats med MSA är det möjligt att nuvarande transgena modeller inte helt återspeglar det mänskliga sjukdomsförloppet. Upptäckten av inducerade pluripotenta stamceller (iPSC)... (More)
Komplexiteten hos a-synukleinopatier, som inkluderar multipel systematrofi (MSA) och Parkinsons sjukdom (PS), är inte helt klarlagd. Det är känt att patologisk ansamling av a-synuclein (a-syn) till fiberlika proteinaggregat är ett cellulärt kännetecken för dessa sjukdomar. a-Syn-positiva aggregat förekommer i nervceller i PS och Lewy body demens (LBD) och i oligodendrocyter i MSA. Mycket forskning har fokuserat på att använda djurmodeller som patokopierar och fenokopierar PS och MSA för att undersöka sjukdomsförloppet. Eftersom ingen genetisk koppling har associerats med MSA är det möjligt att nuvarande transgena modeller inte helt återspeglar det mänskliga sjukdomsförloppet. Upptäckten av inducerade pluripotenta stamceller (iPSC) förändrade livsvetenskaper och gjorde det för första gången möjligt att genomföra storskaligt experimentellt arbete med hjälp av patientceller. Eftersom dessa celler är embryonala pluripotentliknande, kan deras användning hjälpa till att upptäcka mekanismer för tidig sjukdom, eftersom de kan differentieras till omogna hjärnceller. Trots intensiva forskningsinsatser som gjorts för att förstå sjukdomsförloppet för PS och MSA kvarstår många frågor, särskilt ursprunget till a-syn i oligodendrocyter och möjlig toxicitet för dessa celler. Arbetet som presenteras i denna avhandling syftar till att 1) generera patient-iPSCbaserade modeller, 2) utveckla effektiva metoder för att generera dopaminproducerande nervceller och oligodendrocyter från iPSC, och 3) studera oligodendrocyters roll i synukleinopatier, för att få insikt i oligodendrocyter (dys)funktion i PS och MSA. Här redogör vi för att under oligodendrocytutveckling och i den mänskliga hjärnan uttrycks SNCA-genen som kodar för a-syn differentiellt i oligodendrocyter. Eftersom nervceller som uttrycker patogena former av a-syn uppvisar cellulära förändringar, antog vi att oligodendrocyter med samma genetiska bakgrund också bör påverkas.
För första gången visar vi att iPSC-härledda oligodendrocyter genererade från PSpatienter som bär variationen p.A53T i a-syn eller en triplikering av SNCA-lokuset och från MSA-patienter visar försämrad differentiering och mognad. Detta stöds vidare av observationer från experiment som involverade musembryonala stamcells-härledda oligodendrocyter genererade från M83-transgena musmodellen av PS. Dessutom visar vi att p.A53T a-syn och MSA oligodendrocyter uppvisar en avvikelse i deras fenotyp, antar en immunreaktiv fenotyp istället för att bli myeliniserande oligodendroglia. Slutligen avslöjar våra transkriptomiska data ytterligare förändringar i medfödda inflammatoriska komponenter, med differentiellt uttryck av komplementproteiner, MHC-klass och immunproteasomgener i p.A53T a-syn och MSA-oligodendrocyter.
Denna avhandling består av en unik uppsättning studier som tar upp avgörande frågor relaterade till ursprunget till a-syn i oligodendroglia och fokuserar på att belysa de cellulära förändringarna i oligodendrocyter i PS och MSA. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Associate professor Relvas, João, Department of Biomedicine, Porto University, Porto, Portugal
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Synucleinopathies, iPSCs, oligodendrocytes, alpha-synuclein, HLA, cell maturation, immunoproteasome
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
issue
2020:50
pages
119 pages
publisher
Lund University, Faculty of Medicine
defense location
Segerfalksalen, BMC A10, Sölvegatan 17 i Lund or by Zoom at https://lu-se.zoom.us/j/164019709
defense date
2020-04-30 13:30:00
ISSN
1652-8220
ISBN
978-91-7619-911-4
language
English
LU publication?
yes
id
3ec92891-f5df-4adb-a618-fe168fbd99be
date added to LUP
2020-03-30 11:57:51
date last changed
2020-04-09 12:49:52
@phdthesis{3ec92891-f5df-4adb-a618-fe168fbd99be,
  abstract     = {The complexity of a-synucleinopathies, which include multiple system atrophy (MSA) and Parkinson’s disease (PD), is not entirely understood. It is known that pathological accumulation of a-synuclein (a-syn) into proteinaceous aggregates is a cellular  hallmark of these diseases. a-Syn positive aggregates appear in neurons in PD and dementia with Lewy bodies (DLB), and in oligodendrocytes in MSA. Much research has focused on using animal models that pathocopy and phenocopy PD and MSA to investigate the disease pathogenesis. However, as no genetic link has been associated with MSA, it is possible that current transgenic models do not fully reflect the human pathology. The discovery of induced pluripotent stem cells (iPSCs) changed life science, and allowed for the first time to conduct large scale experimental work using patient cells. Since these cells are embryonic pluripotentlike, their use can help to unravel early disease mechanisms, as they can be differentiated into young brain cells.<br/>Despite intense research efforts made to understand the pathogenesis of PD and MSA, several questions remain unanswered, in particular the origin of a-syn in oligodendrocytes and possible toxicity to these cells.<br/>The work presented in this thesis aims to 1) generate patient iPSC- based models, 2) develop efficient protocols to generate dopaminergic neurons and oligodendrocytes from iPSCs, and 3) study the role of oligodendrocytes in synucleinopathies, to gain insights into oligodendrocyte (dys)function in PD and MSA. Here, we report that during<br/>oligodendrocyte development and in the human brain, the SNCA gene encoding for a-syn is differentially expressed in oligodendrocytes. Since neurons expressing pathogenic forms of a-syn exhibit cellular alterations, we hypothesized that oligodendrocytes having the same genetic background should also be affected.<br/>For the first time, we show that iPSC-derived oligodendrocytes generated from PD patients carrying the variation p.A53T in a-syn or a triplication of the SNCA locus, and from MSA patients, display impaired differentiation and maturation. This was further supported by observations from experiments involving mouse embryonic stem cell<br/>(mESC)-derived oligodendrocytes generated from the M83 transgenic mouse model of PD. Moreover, we demonstrate that p.A53T a-syn and MSA oligodendrocytes exhibit a deviation in their phenotype, adopting an immune-reactive phenotype and not myelinating oligodendroglia. Finally, our transcriptomic data further reveal<br/>alterations in innate inflammatory components, with differential expression of complement proteins, MHC-class and immune-proteasome genes in p.A53T a-syn and MSA oligodendrocytes. <br/>This thesis is composed of a unique set of studies addressing crucial questions related to the origin of a-syn in oligodendroglia, and focuses on elucidating the cellular alterations in oligodendrocytes in PD and MSA.},
  author       = {Azevedo, Carla},
  isbn         = {978-91-7619-911-4},
  issn         = {1652-8220},
  language     = {eng},
  number       = {2020:50},
  publisher    = {Lund University, Faculty of Medicine},
  school       = {Lund University},
  series       = {Lund University, Faculty of Medicine Doctoral Dissertation Series},
  title        = {Oligodendroglial (dys)function in alpha-synucleinopathies},
  url          = {https://lup.lub.lu.se/search/ws/files/77826183/Summary_Carla_Azevedo.pdf},
  year         = {2020},
}