Nitrotyrosine Immunoreactivity

Irie Y, Saeki M, Kamisaki Y, Martin E, Murad F (2003) Histone HI.2 is a substrate for denitrase, an activity that reduces nitrotyrosine immunoreactivity in proteins. Proc Natl Acad Sci U S A 100 5634-5639... 

Both iNOS and nitrotyrosine, a marker of per-oxynitrite formation, were localised in rat skeletal muscle after a period of 2 h warm ischaemia and reperfusion exclusively to mast cells except after 24 h reperfusion when some macrophages and neutrophils also showed positive immunoreactivity (Messina et al. 2000). 

Hyperglycaemia induced prior to ischaemia resulted in earher infarction that correlated with increased immunoreactivity for iNOS, Mn superoxide dismutase and nitrotyrosine (Ste-Marie etal. 

Mendes, R.V., Martins, A.R., de Nucci, G., Murad, E, and Soares, F.A. (2(X)1). Expression of nitric oxide synthase isoforms and nitrotyrosine immunoreactivity by B-cell non-Hodgkin s lymphomas and multiple myeloma. Histopathology 39, 172-178. 

Porphyrin (AEOL I0150)-treated and control cohort mice were sacrificed 10 days after symptom onset and spinal cord sections compared. Left panel shows nitrotyrosine immunoreactivity in spinal cord of G93A mouse and r htpanel is age-matched GPS A mouse treated with Mn porphyrin. Note that staining in treated moiae (n = 7) is decreased relative to untreated (n = 6), particularly in region of ventral horn (see arrows), which contains motor neuron cell bodies. 

Nitration of critical cellular targets such as tyrosine kinase receptors or neurofilament proteins could injure motor neurons, and since motor neurons cannot regenerate, this damage may accumulate and eventually cause the cell to die. Increased 3-nitrotyrosine immunoreactivity is observed in motor neurons of both sporadic and familial ALS patients (27). As with the markers of oxidative damage mentioned above, however, it is unknown whether the observed increased levels of nitrotyrosine are the cause or a downstream effect due to neuronal dysfunction. 

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