Temporal patterns of tyrosine nitration in embryo heart development

Abstract

Tyrosine nitration is a biomarker for the production of peroxynitrite and other reactive nitrogen species. Nitrotyrosine immunoreactivity is present in many pathological conditions including several cardiac diseases. Because the events observed during heart failure may recapitulate some aspects of development, we tested whether nitrotyrosine is present during normal development of the rat embryo heart and its potential relationship in cardiac remodeling through apoptosis. Nitric oxide (NO) production is highly dynamic during development, but whether peroxynitrite and nitrotyrosine are formed during normal embryonic development has received little attention. Rat embryo hearts exhibited strong nitrotyrosine immunoreactivity in endocardial and myocardial cells of the atria and ventricles from E12 to E18. After E18, nitrotyrosine staining faded and disappeared entirely by birth. Tyrosine nitration in the myocardial tissue coincided with elevated protein expression of nitric oxide synthases (eNOS and iNOS). The immunoreactivity for these NOS isoforms remained elevated even after nitrotyrosine had disappeared. Tyrosine nitration did not correlate with cell death or proliferation of cardiac cells. Analysis of tryptic peptides by MALDI-TOF shows that nitration occurs in actin, myosin, and the mitochondrial ATP synthase alpha chain. These results suggest that reactive nitrogen species are not restricted to pathological conditions but may play a role during normal embryonic development.

Reactive nitrogen species in cellular signaling

“…This chaperone has a very broad range of functions: protein folding, stabilization, translocation, activity modulation, and degradation. [90][91][92] Further study revealed that nitration of a single tyrosine residue on Hsp90 (Y33 or Y56) was necessary and sufficient to cause a gain of function converting this pro-survival chaperone into a pro-apoptotic protein. 62 Nitrated Hsp90 has been identified in the spinal cords of patients suffering from sporadic ALS and in SOD mutant ALS model mice.…”

“…This chaperone has a very broad range of functions: protein folding, stabilization, translocation, activity modulation, and degradation. 90–92…”

Longitudinal quantification of radical bursts during pulmonary ischaemia and reperfusion

“…ONOO-formation was quantified by observing tyrosin nitrosation [8]. Snap-frozen lungs were homogenized (Qiagen TissueRuptor, Qiagen, Germany) in cold RIPA lysis buffer and kept on ice.…”

Design of a Protein Motif Responsive to Tyrosine Nitration and an Encoded Turn-Off Sensor of Tyrosine Nitration

“…12,[29][30][31] Alternately, a potential regulatory role for nitrotyrosine was observed in cardiac development of embryonic rats, associated with the regulation of myosin heavy chain isoforms. 32 Most generally, increased levels of tyrosine nitration are associated with the inflammation response, where both nitric oxide and superoxide are central molecules. 1,6,[33][34][35][36] Tyrosine nitration reduces the pK a of the tyrosine phenol, from approximately 10 to approximately 7, due to the electron-withdrawing nature of the nitro group, which stabilizes the phenolate.…”