TY - JOUR
T1 - Co-aggregation of RNA binding proteins in ALS spinal motor neurons
T2 - Evidence of a common pathogenic mechanism
AU - Keller, Brian A.
AU - Volkening, Kathryn
AU - Droppelmann, Cristian A.
AU - Ang, Lee Cyn
AU - Rademakers, Rosa
AU - Strong, Michael J.
N1 - Funding Information:
Acknowledgments This work was supported by the McFeat Family Fund and the Michael Halls Endowment. The authors declare no conflicts of interest. Postmortem spinal cord tissues were provided by the Department of Pathology at the London Health Sciences Center at the University of Western Ontario, London, Canada, and were obtained using standard autopsy consents. We thank Drs Janice Robertson and John Ravits for making available additional mtSOD1 slides. We are thankful to the donors and their families who contributed to this work through the donation of tissues and their consent to diagnostic confirmation and research. We also wish to thank Dr. Stephen Pasternak for his assistance with Bitplane’s Imaris image analysis software.
PY - 2012/11
Y1 - 2012/11
N2 - While the pathogenesis of amyotrophic lateral sclerosis (ALS) remains to be clearly delineated, there is mounting evidence that altered RNA metabolism is a commonality amongst several of the known genetic variants of the disease. In this study, we evaluated the expression of 10 ALS-associated proteins in spinal motor neurons (MNs) in ALS patients with mutations in C9orf72 (C9orf72 GGGGCC-ALS; n = 5), SOD1 (mtSOD1-ALS; n = 9), FUS/TLS (mtFUS/TLS-ALS; n = 2), or TARDBP (mtTDP-43-ALS; n = 2) and contrasted these to cases of sporadic ALS (sALS; n = 4) and familial ALS without known mutations (fALS; n = 2). We performed colorimetric immunohistochemistry (IHC) using antibodies against TDP-43, FUS/TLS, SOD1, C9orf72, ubiquitin, sequestosome 1 (p62), optineurin, phosphorylated high molecular weight neurofilament, peripherin, and Rhoguanine nucleotide exchange factor (RGNEF). We observed that RGNEF-immunoreactive neuronal cytoplasmic inclusions (NCIs) can co-localize with TDP-43, FUS/ TLS and p62 within spinal MNs. We confirmed their capacity to interact by co-immunoprecipitations. We also found that mtSOD1-ALS cases possess a unique IHC signature, including the presence of C9orf72-immunoreactive diffuse NCIs, which allows them to be distinguished from other variants of ALS at the level of light microscopy. These findings support the hypothesis that alterations in RNA metabolism are a core pathogenic pathway in ALS. We also conclude that routine IHC-based analysis of spinal MNs may aid in the identification of families not previously suspected to harbor SOD1 mutations.
AB - While the pathogenesis of amyotrophic lateral sclerosis (ALS) remains to be clearly delineated, there is mounting evidence that altered RNA metabolism is a commonality amongst several of the known genetic variants of the disease. In this study, we evaluated the expression of 10 ALS-associated proteins in spinal motor neurons (MNs) in ALS patients with mutations in C9orf72 (C9orf72 GGGGCC-ALS; n = 5), SOD1 (mtSOD1-ALS; n = 9), FUS/TLS (mtFUS/TLS-ALS; n = 2), or TARDBP (mtTDP-43-ALS; n = 2) and contrasted these to cases of sporadic ALS (sALS; n = 4) and familial ALS without known mutations (fALS; n = 2). We performed colorimetric immunohistochemistry (IHC) using antibodies against TDP-43, FUS/TLS, SOD1, C9orf72, ubiquitin, sequestosome 1 (p62), optineurin, phosphorylated high molecular weight neurofilament, peripherin, and Rhoguanine nucleotide exchange factor (RGNEF). We observed that RGNEF-immunoreactive neuronal cytoplasmic inclusions (NCIs) can co-localize with TDP-43, FUS/ TLS and p62 within spinal MNs. We confirmed their capacity to interact by co-immunoprecipitations. We also found that mtSOD1-ALS cases possess a unique IHC signature, including the presence of C9orf72-immunoreactive diffuse NCIs, which allows them to be distinguished from other variants of ALS at the level of light microscopy. These findings support the hypothesis that alterations in RNA metabolism are a core pathogenic pathway in ALS. We also conclude that routine IHC-based analysis of spinal MNs may aid in the identification of families not previously suspected to harbor SOD1 mutations.
KW - Amyotrophic lateral sclerosis
KW - C9orf72
KW - RGNEF
KW - RNA binding proteins
KW - Superoxide dismutase
KW - Ubiquitination
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U2 - 10.1007/s00401-012-1035-z
DO - 10.1007/s00401-012-1035-z
M3 - Article
C2 - 22941224
AN - SCOPUS:84870994113
SN - 0001-6322
VL - 124
SP - 733
EP - 747
JO - Acta neuropathologica
JF - Acta neuropathologica
IS - 5
ER -