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Cellular alterations identified in pluripotent stem cell-derived midbrain spheroids generated from a female patient with progressive external ophthalmoplegia and parkinsonism who carries a novel variation (p.Q811R) in the POLG1 gene.
- Source :
-
Acta neuropathologica communications [Acta Neuropathol Commun] 2019 Dec 16; Vol. 7 (1), pp. 208. Date of Electronic Publication: 2019 Dec 16. - Publication Year :
- 2019
-
Abstract
- Variations in the POLG1 gene encoding the catalytic subunit of the mitochondrial DNA polymerase gamma, have recently been associated with Parkinson's disease (PD), especially in patients diagnosed with progressive external ophthalmoplegia (PEO). However, the majority of the studies reporting this association mainly focused on the genetic identification of the variation in POLG1 in PD patient primary cells, and determination of mitochondrial DNA copy number, providing little information about the cellular alterations existing in patient brain cells, in particular dopaminergic neurons. Therefore, through the use of induced pluripotent stem cells (iPSCs), we assessed cellular alterations in novel p.Q811R POLG1 (POLG1 <superscript>Q811R</superscript> ) variant midbrain dopaminergic neuron-containing spheroids (MDNS) from a female patient who developed early-onset PD, and compared them to cultures derived from a healthy control of the same gender. Both POLG1 variant and control MDNS contained functional midbrain regionalized TH/FOXA2-positive dopaminergic neurons, capable of releasing dopamine. Western blot analysis identified the presence of high molecular weight oligomeric alpha-synuclein in POLG1 <superscript>Q811R</superscript> MDNS compared to control cultures. In order to assess POLG1 <superscript>Q811R</superscript> -related cellular alterations within the MDNS, we applied mass-spectrometry based quantitative proteomic analysis. In total, 6749 proteins were identified, with 61 significantly differentially expressed between POLG1 <superscript>Q811R</superscript> and control samples. Pro- and anti-inflammatory signaling and pathways involved in energy metabolism were altered. Notably, increased glycolysis in POLG1 <superscript>Q811R</superscript> MDNS was suggested by the increase in PFKM and LDHA levels and confirmed using functional analysis of glycolytic rate and oxygen consumption levels. Our results validate the use of iPSCs to assess cellular alterations in relation to PD pathogenesis, in a unique PD patient carrying a novel p.Q811R variation in POLG1, and identify several altered pathways that may be relevant to PD pathogenesis.
- Subjects :
- Adult
Female
Humans
Mesencephalon pathology
Mesencephalon physiology
Ophthalmoplegia, Chronic Progressive External complications
Ophthalmoplegia, Chronic Progressive External diagnosis
Parkinsonian Disorders complications
Parkinsonian Disorders diagnosis
Pluripotent Stem Cells pathology
Proteomics methods
Spheroids, Cellular pathology
DNA Polymerase gamma genetics
Genetic Variation genetics
Ophthalmoplegia, Chronic Progressive External genetics
Parkinsonian Disorders genetics
Pluripotent Stem Cells physiology
Spheroids, Cellular physiology
Subjects
Details
- Language :
- English
- ISSN :
- 2051-5960
- Volume :
- 7
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Acta neuropathologica communications
- Publication Type :
- Academic Journal
- Accession number :
- 31843010
- Full Text :
- https://doi.org/10.1186/s40478-019-0863-7