Aberrant association of misfolded SOD1 with Na+/K+ATPase-α3 impairs its activity and contributes to motor neuron vulnerability in ALS.

Ruegsegger, Céline; Maharjan, Niran; Goswami, Anand; Filézac de l’Etang, Audrey; Weis, Joachim; Troost, Dirk; Heller, Manfred; Gut, Heinz; Saxena, Smita (2016). Aberrant association of misfolded SOD1 with Na+/K+ATPase-α3 impairs its activity and contributes to motor neuron vulnerability in ALS. Acta neuropathologica, 131(3), pp. 427-451. Springer 10.1007/s00401-015-1510-4

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Amyotrophic lateral sclerosis (ALS) is an adult onset progressive motor neuron disease with no cure. Transgenic mice overexpressing familial ALS associated human mutant SOD1 are a commonly used model for examining disease mechanisms. Presently, it is well accepted that alterations in motor neuron excitability and spinal circuits are pathological hallmarks of ALS, but the underlying molecular mechanisms remain unresolved. Here, we sought to understand whether the expression of mutant SOD1 protein could contribute to altering processes governing motor neuron excitability. We used the conformation specific antibody B8H10 which recognizes a misfolded state of SOD1 (misfSOD1) to longitudinally identify its interactome during early disease stage in SOD1G93A mice. This strategy identified a direct isozyme-specific association of misfSOD1 with Na+/K+ATPase-α3 leading to the premature impairment of its ATPase activity. Pharmacological inhibition of Na+/K+ATPase-α3 altered glutamate receptor 2 expression, modified cholinergic inputs and accelerated disease pathology. After mapping the site of direct association of misfSOD1 with Na+/K+ATPase-α3 onto a 10 amino acid stretch that is unique to Na+/K+ATPase-α3 but not found in the closely related Na+/K+ATPase-α1 isozyme, we generated a misfSOD1 binding deficient, but fully functional Na+/K+ATPase-α3 pump. Adeno associated virus (AAV)-mediated expression of this chimeric Na+/K+ATPase-α3 restored Na+/K+ATPase-α3 activity in the spinal cord, delayed pathological alterations and prolonged survival of SOD1G93A mice. Additionally, altered Na+/K+ATPase-α3 expression was observed in the spinal cord of individuals with sporadic and familial ALS. A fraction of sporadic ALS cases also presented B8H10 positive misfSOD1 immunoreactivity, suggesting that similar mechanism might contribute to the pathology.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Service Sector > Institute of Pathology
08 Faculty of Science > Department of Biology > Institute of Cell Biology
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Protein- und Zellbiologie

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Ruegsegger, Céline; Maharjan, Niran; Weis, Joachim; Heller, Manfred and Saxena, Smita

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0001-6322

Publisher:

Springer

Funders:

[4] Swiss National Science Foundation
[UNSPECIFIED] Frick foundation for ALS research

Language:

English

Submitter:

Prof. Smita Saxena

Date Deposited:

11 Mar 2016 09:16

Last Modified:

12 Apr 2017 14:31

Publisher DOI:

10.1007/s00401-015-1510-4

PubMed ID:

26619836

BORIS DOI:

10.7892/boris.79429

URI:

https://boris.unibe.ch/id/eprint/79429

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