Wong N K, Strong M J
Department of Pathology, The University of Western Ontario, The John P. Robarts Research Institute, London, Canada.
Eur J Cell Biol. 1998 Dec;77(4):338-43. doi: 10.1016/S0171-9335(98)80092-7.
Nitration of neurofilament (NF) has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Evidence of such includes elevated 3-nitrotyrosine levels in spinal cord tissue and localized nitrotyrosine immunoreactivity with neurofilamentous aggregates in cortical and spinal motor neurons. To determine if neuronal nitric oxide synthase (nNOS) and inducible NOS (iNOS) are the sources of nitric oxide in sporadic ALS (sALS), particularly through over-expression of the enzyme, steady-state mRNA levels of these isoforms were studied by in situ hybridization. Paraffin-embedded, archival cervical spinal cord tissues from 7 sALS and 6 control cases were used. 35S-labeled riboprobes were generated from partial cDNAs. Immunohistochemistry was utilized to confirm results of iNOS hybridization. We observed that nNOS mRNA was constitutively expressed in cervical spinal motor neurons. However, iNOS mRNA and iNOS immunoreactivity was not observed in ALS or control motor neurons. Our observations suggest that the source of nitric oxide is the endogenous nNOS. Together with the results from other immunohistochemical studies, we further hypothesize a possible role of translational deregulation of nNOS in sALS.
神经丝（NF）的硝化作用与肌萎缩侧索硬化症（ALS）的发病机制有关。相关证据包括脊髓组织中3-硝基酪氨酸水平升高，以及皮质和脊髓运动神经元中神经丝聚集物的局部硝基酪氨酸免疫反应性。为了确定神经元型一氧化氮合酶（nNOS）和诱导型一氧化氮合酶（iNOS）是否是散发性ALS（sALS）中一氧化氮的来源，特别是通过该酶的过度表达，通过原位杂交研究了这些同工型的稳态mRNA水平。使用了来自7例sALS和6例对照病例的石蜡包埋的存档颈脊髓组织。从部分cDNA生成35S标记的核糖探针。利用免疫组织化学来确认iNOS杂交的结果。我们观察到nNOS mRNA在颈脊髓运动神经元中组成性表达。然而，在ALS或对照运动神经元中未观察到iNOS mRNA和iNOS免疫反应性。我们的观察结果表明，一氧化氮的来源是内源性nNOS。结合其他免疫组织化学研究的结果，我们进一步推测nNOS翻译失调在sALS中的可能作用。
