Acyloxy nitroso compounds inhibit LIF signaling in endothelial cells and cardiac myocytes: evidence that STAT3 signaling is redox-sensitive

• Published in: PloS one Vol. 7; no. 8; p. e43313
• Main Authors: Zgheib, Carlos, Kurdi, Mazen, Zouein, Fouad A, Gunter, Barak W, Stanley, Brian A, Zgheib, Joe, Romero, Damian G, King, S Bruce, Paolocci, Nazareno, Booz, George W
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 15-08-2012; Public Library of Science (PLoS)
• Subjects: Acetic acid; Activation; Animals; Binding sites; Biochemistry; Biology; Cardiology; Cardiomyocytes; Catalysis; Catalytic activity; CCAAT/enhancer-binding protein; Cell adhesion; Coronary artery disease; Cysteine; Cytokines; Data analysis; Departments; Dimerization; Endothelial cells; Endothelium; Endothelium, Vascular - cytology; Gene expression; Glutathione - chemistry; Health aspects; Heart; Heart cells; Heart diseases; Heart failure; Humans; Inflammation; Inhibition; Intercellular adhesion molecule 1; Ischemia; Janus kinase; Kinases; Leukemia; Leukemia inhibitory factor; Leukemia Inhibitory Factor - metabolism; Male; Medicine; Mice; Mice, Inbred C57BL; Microcirculation; Microvasculature; Muscle Cells - cytology; Myocytes; Myocytes, Cardiac - cytology; Neonates; Nitrogen - chemistry; Nitroso compounds; Oxidation-Reduction; Oxidative Stress; Pharmacology; Phosphorylation; Pretreatment; Protein binding; Proteins; Rats; Rats, Sprague-Dawley; Rodents; Salts; Signal Transduction; Signaling; Stat3 protein; STAT3 Transcription Factor - metabolism; Stem cells; Toxicology; Mississippi; United States > US; Maryland; Baltimore Maryland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0043313

We previously showed that oxidative stress inhibits leukemia inhibitory factor (LIF) signaling by targeting JAK1, and the catalytic domains of JAK 1 and 2 have a cysteine-based redox switch. Thus, we postulated that the NO sibling and thiophylic compound, nitroxyl (HNO), would inhibit LIF-induced JAK-STAT3 activation. Pretreatment of human microvascular endothelial cells (HMEC-1) or neonatal rat cardiomyocytes with the HNO donors Angeli's salt or nitrosocyclohexyl acetate (NCA) inhibited LIF-induced STAT3 activation. NCA pretreatment also blocked the induction of downstream inflammatory genes (e.g. intercellular adhesion molecule 1, CCAAT/enhancer binding protein delta). The related 1-nitrosocyclohexyl pivalate (NCP; not a nitroxyl donor) was equally effective in inhibiting STAT3 activation, suggesting that these compounds act as thiolate targeting electrophiles. The JAK1 redox switch is likely not a target of acyloxy nitroso compounds, as NCA had no effect on JAK1 catalytic activity and only modestly affected JAK1-induced phosphorylation of the LIF receptor. However, pretreatment of recombinant human STAT3 with NCA or NCP reduced labeling of free sulfhydryl residues. We show that NCP in the presence of diamide enhanced STAT3 glutathionylation and dimerization in adult mouse cardiac myocytes and altered STAT3 under non-reducing conditions. Finally, we show that monomeric STAT3 levels are decreased in the Gαq model of heart failure in a redox-sensitive manner. Altogether, our evidence indicates that STAT3 has redox-sensitive cysteines that regulate its activation and are targeted by HNO donors and acyloxy nitroso compounds. These findings raise the possibility of new therapeutic strategies to target STAT3 signaling via a redox-dependent manner, particularly in the context of cardiac and non-cardiac diseases with prominent pro-inflammatory signaling.