Colocalization of NOS and SOD1 in neurofilament accumulation within motor neurons of amyotrophic lateral sclerosis: an immunohistochemical study

Author: Chou, S.M.; Wang, H.S.; Komai, K.

Description: Peroxynitrite, formed from nitric oxide and superoxide, may affect neurofilament assembly and cause neurofilament accumulation in motoneurons. This hypothesis may reconcile the mutations of two genes: superoxide dismutase-1 in some patients with familial amyotrophic lateral sclerosis, and the gene for the heavy neurofilament in some patients with sporadic amyotrophic lateral sclerosis previously reported. We found colocalization of superoxide dismutase-1 and nitric oxide synthase in the foci of neurofilament accumulation as ‘conglomerates’ in upper motor neurons and ‘axonal spheroids’ in lower motor neurons. In addition, all the specific molecules related to the reactions, including calmodulin, 3′, 5′-cyclic guanosine-monophosphate, citrulline, and nitrotyrosine were found strongly immunopositive in the site of neurofilament accumulation. Our data support the view that the neurofilament aggregates are tightly linked with superoxide dismutase-1 and nitric oxide synthase activities. Both enzymes may focally contribute to peroxynitrite formation at light neurofilament, which is rich in both tyrosine and arginine residues and hence considered as the vulnerable site for nitrotyrosine formation. Nitrotyrosine is known to inhibit phosphorylation and if it impairs phosphorylation of neurofilament subunits, either light or heavy, may alter the slow axonal transport culminating in proximo-distal accumulation of NF and slowly progressive motoneuron death.

Subject headings: Amyotrophic Lateral Sclerosis/enzymology; Citrulline/metabolism; Cyclic GMP/metabolism; Cytoplasm/metabolism; Humans; Immunohistochemistry; Motor Neurons/chemistry/enzymology; Neurofilament Proteins/metabolism; Nitrates/metabolism; Nitric Oxide/analysis/metabolism; Nitrogen/metabolism; Oxidation-Reduction; Superoxide Dismutase/analysis/metabolism; Tyrosine/metabolism

Publication year: 1996

Journal or book title: Journal of Chemical Neuroanatomy

Volume: 10

Issue: 3-4

Pages: 249-258

Find the full text : https://www.sciencedirect.com/science/article/pii/0891061896001378

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Type: Journal Article

Serial number: 1254