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Updated: Apr 13, 2026
A Murine Closed-chest Model of Myocardial Ischemia and Reperfusion
Published on: July 17, 2012
Nitrative inactivation of thioredoxin-1 and its role in postischemic myocardial apoptosis
Ling Tao1, Xiangying Jiao, Erhe Gao
1Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA, USA.
Background:
Intracellular proteins involved in oxidative stress and apoptosis are nitrated in diseased tissues but not in normal tissues; definitive evidence to support a causative link between a specific protein that is nitratively modified with tissue injury in a specific disease is limited, however. The aims of the present study were to determine whether thioredoxin (Trx), a novel antioxidant and antiapoptotic molecule, is susceptible to nitrative inactivation and to establish a causative link between Trx nitration and postischemic myocardial apoptosis.
Methods And Results:
In vitro exposure of human Trx-1 to 3-morpholinosydnonimine resulted in significant Trx-1 nitration and almost abolished Trx-1 activity. 3-morpholinosydnonimine-induced nitrative Trx-1 inactivation was completely blocked by MnTE-2-PyP(5+) (a superoxide dismutase mimetic) and markedly attenuated by PTIO (a nitric oxide scavenger). Administration of either reduced or oxidized Trx-1 in vivo attenuated myocardial ischemia/reperfusion injury (>50% reduction in apoptosis and infarct size, P<0.01). However, administration of nitrated Trx-1 failed to exert a cardioprotective effect. In cardiac tissues obtained from ischemic/reperfused heart, significant Trx-1 nitration was detected, Trx activity was markedly inhibited, Trx-1/ASK1 (apoptosis signal-regulating kinase-1) complex formation was abolished, and apoptosis signal-regulating kinase-1 activity was increased. Treatment with either FP15 (a peroxynitrite decomposition catalyst) or MnTE-2-PyP(5+) 10 minutes before reperfusion blocked nitrative Trx inactivation, attenuated apoptosis signal-regulating kinase-1 activation, and reduced postischemic myocardial apoptosis.
Conclusions:
These results strongly suggest that nitrative inactivation of Trx plays a proapoptotic role under those pathological conditions in which production of reactive nitrogen species is increased and that antinitrating treatment may have therapeutic value in those diseases, such as myocardial ischemia/reperfusion, in which pathological apoptosis is increased.
Insights
Nitrative modification inactivates thioredoxin (Trx), a key antioxidant, leading to increased apoptosis in conditions like myocardial ischemia. Preventing Trx nitration may offer therapeutic benefits for related diseases.
Area of Science:
- Biochemistry
- Molecular Biology
- Cardiovascular Research
Background:
- Oxidative stress and apoptosis involve nitrated intracellular proteins in diseased tissues.
- Limited evidence links specific nitrated proteins to tissue injury in diseases.
- Thioredoxin (Trx), an antioxidant and antiapoptotic molecule, was investigated for susceptibility to nitrative inactivation.
Purpose of the Study:
- To determine if thioredoxin (Trx) is inactivated by nitration.
- To establish a causal link between Trx nitration and myocardial apoptosis after ischemia.
Main Methods:
- In vitro nitration of human Trx-1 using 3-morpholinosydnonimine.
- Assessment of Trx-1 activity and protection by antioxidants/scavengers (MnTE-2-PyP(5+), PTIO).
- In vivo administration of Trx-1 (reduced, oxidized, or nitrated) in a myocardial ischemia/reperfusion model.
- Analysis of cardiac tissues for Trx-1 nitration, activity, Trx-1/ASK1 complex, and apoptosis signal-regulating kinase-1 (ASK1) activity.
- Treatment with peroxynitrite decomposition catalyst (FP15) or MnTE-2-PyP(5+) before reperfusion.
Main Results:
- In vitro nitration significantly reduced Trx-1 activity, an effect blocked by MnTE-2-PyP(5+) and attenuated by PTIO.
- In vivo administration of non-nitrated Trx-1 reduced apoptosis and infarct size in ischemic hearts.
- Nitrated Trx-1 failed to provide cardioprotection.
- Ischemic cardiac tissues showed increased Trx-1 nitration, inhibited Trx activity, abolished Trx-1/ASK1 complex, and increased ASK1 activity.
- Pre-reperfusion treatment with FP15 or MnTE-2-PyP(5+) prevented Trx inactivation, attenuated ASK1 activation, and reduced apoptosis.
Conclusions:
- Nitrative inactivation of Trx contributes to apoptosis in conditions with increased reactive nitrogen species.
- Antinitrating treatments show potential therapeutic value for diseases involving pathological apoptosis, such as myocardial ischemia/reperfusion.
