Signs of early cellular dysfunction in multiple system atrophy. (17th September 2020)

• Record Type: Journal Article
• Authors: Herrera‐Vaquero, M.; Heras‐Garvin, A.; Krismer, F.; Deleanu, R.; Boesch, S.; Wenning, G. K.; Stefanova, N.
• Is Part Of: Neuropathology & applied neurobiology. Volume 47:Number 2(2021)
• Page Start: 268
• Page End: 282
• Publication Date: 2020-09-17
• Subjects: multiple system atrophy -- induced pluripotent stem cells -- mitochondria -- high resolution respirometry -- α‐synuclein -- oxidative stress; Nervous system -- Diseases -- Pathology -- Periodicals; Nervous system -- Diseases -- Periodicals; 616.8
• DOI: 10.1111/nan.12661
• Languages: English
• ISSNs: 0305-1846

Abstract

Abstract : Aims: Multiple system atrophy (MSA) is a fatal neurodegenerative disease that belongs to the family of α‐synucleinopathies. At post mortem examination, intracellular inclusions of misfolded α‐synuclein are found in neurons and oligodendrocytes and are considered to play a significant role in the pathogenesis. However, the early steps of the disease process are unknown and difficult to study in tissue derived from end‐stage disease. Methods: Induced pluripotent stem cells (iPSCs) were generated from patients' and control skin fibroblasts and differentiated into NCAM‐positive neural progenitor cells (NPCs). The mitochondrial morphology and function were assessed by immunocytochemistry and high resolution respirometry. The ability to cope with exogenous oxidative stress was tested by exposure to different doses of luperox. The expression of α‐synuclein was studied by immunocytochemistry. Results: We identified increased tubulation of mitochondria with preserved respiration profile in MSA‐derived NPCs. Exposure of these cells to exogenous oxidative stress even at low doses, triggered an excessive generation of reactive oxygen species (ROS) and cleavage of caspase‐3. MSA‐derived NPCs did not present changed levels of SNCA gene expression nor intracellular aggregates of α‐synuclein. However, we identified disease‐related translocation of α‐synuclein to the nucleus. Conclusions: Our results show early cellular dysfunction in MSA‐derived NPCs. We identified changes in the redox homeostasis which are functionally compensated at baseline but cause increased susceptibility to exogenous oxidative stress. In addition, nuclear translocation of α‐synuclein in MSA‐derived NPCs supports an early cellular stress response which may precede the neurodegenerative process in this disorder. Abstract : Neural progenitors derived from iPSCs of patients with multiple system atrophy show changes in the mitochondrial morphology, relocation of α‐synuclein to the nucleus, and increased susceptibility to exogenous oxidative stress. The findings suggest early cellular dysfunction preceding α‐synuclein aggregate formation in this disorder.