Stimulation of “Stress-regulated” Mitogen-activated Protein Kinases (Stress-activated Protein Kinases/c-Jun N-terminal Kinases and p38-Mitogen-activated Protein Kinases) in Perfused Rat Hearts by Oxidative and Other Stresses

Abstract

"Stress-regulated" mitogen-activated protein kinases (SR-MAPKs) comprise the stress-activated protein kinases (SAPKs)/c-Jun N-terminal kinases (JNKs) and the p38-MAPKs. In the perfused heart, ischemia/reperfusion activates SR-MAPKs. Although the agent(s) directly responsible is unclear, reactive oxygen species are generated during ischemia/reperfusion. We have assessed the ability of oxidative stress (as exemplified by H 2 O 2 ) to activate SR-MAPKs in the perfused heart and compared it with the effect of ischemia/reperfusion. H 2 O 2 activated both SAPKs/JNKs and p38-MAPK. Maximal activation by H 2 O 2 in both cases was observed at 0.5 mM. Whereas activation of p38-MAPK by H 2 O 2 was comparable to that of ischemia and ischemia/reperfusion, activation of the SAPKs/JNKs was less than that of ischemia/ reperfusion. As with ischemia/reperfusion, there was minimal activation of the ERK MAPK subfamily by H 2 O 2 . MAPK-activated protein kinase 2 (MAPKAPK2), a downstream substrate of p38-MAPKs, was activated by H 2 O 2 to a similar extent as with ischemia or ischemia/ reperfusion. In all instances, activation of MAPKAPK2 in perfused hearts was inhibited by SB203580, an inhibitor of p38-MAPKs. Perfusion of hearts at high aortic pressure (20 kilopascals) also activated the SRMAPKs and MAPKAPK2. Free radical trapping agents (dimethyl sulfoxide and N-t-butyl-␣-phenyl nitrone) inhibited the activation of SR-MAPKs and MAPKAPK2 by ischemia/reperfusion. These data are consistent with a role for reactive oxygen species in the activation of SR-MAPKs during ischemia/reperfusion.Ischemic and hypertensive myocardial disease is currently a major cause of mortality and morbidity. In these conditions, the heart is exposed to numerous cell stresses including increased production of reactive oxygen species (ROS), 1 ionic imbalances, osmotic stress, mechanical stress, and metabolic deprivation (reviewed in Refs. 1-4). In numerous cell lines, primary cultures, and tissues, cellular stresses activate "stress-regulated" mitogen-activated protein kinases (SR-MAPKs) (reviewed in Refs. 5 and 6). There are two relatively well characterized SR-MAPK families, the stress-activated protein kinases (SAPKs) and the p38-MAPKs. SAPKs are alternatively known as the c-Jun N-terminal kinases (JNKs), although, strictly speaking, the JNK terminology applies to the human enzymes, whereas the SAPK terminology applies to the rat enzymes.Substrates for SAPKs/JNKs include the transcription factors c-Jun (7, 8), ATF-2 (9 -12), and Elk-1 (13, 14). Phosphorylation of these transcription factors in their trans-activation domains leads to an increase in their ability to trans-activate transcription. p38-MAPK (15, 16) (alternatively known as cytokinesuppressive antiinflammatory drug-binding protein (17), reactivating kinase (18), Mxi2 (19), or stress-activated protein kinase-2 (20)) is a mammalian homolog of the yeast osmosensing protein kinase HOG-1. Like SAPKs/JNKs, p38-MAPKs also phosphorylate transcription factors (ATF2 (11), CHOP/ GADD153 (21), and MEF2C (22)),...

The NADPH Oxidase NOX4 Drives Cardiac Differentiation: Role in Regulating Cardiac Transcription Factors and MAP Kinase Activation

“…In accordance with our results, other groups have shown that p38 MAPK is activated by ROS, either generated intracellularly or administered exogenously (Raingeaud et al, 1995;Moriguchi et al, 1996;Huot et al, 1997;Seko et al, 1997;Clerk et al, 1998).…”

Activation of c-Jun N-Terminal Kinases and p38-Mitogen-activated Protein Kinases in Human Heart Failure Secondary to Ischaemic Heart Disease

“…9,25 The activation of MAPKAPK2 is completely inhibited by SB203580, implicating particularly p38-MAPK(␣) and/or p38-MAPK␤ in its activation in the heart. 10 In contrast, the JNKs are not activated during global ischemia but are strongly activated during the reperfusion phase. 9,25,49 This differential activation of the JNKs and p38-MAPKs is unexpected, because in most systems the two pathways tend to be activated in parallel.…”

“…Oxidative stress, as exemplified by low concentrations of H 2 O 2 , activates JNKs, p38-MAPK, and MAPKAPK2 in perfused hearts. 10 Although the particular species may differ, many studies have shown that ROS are formed during ischemia and on subsequent reperfusion (eg, see References 50 and 51). For example, in chick embryo cardiac myocytes, superoxide anion and H 2 O 2 are produced during simulated ischemia, whereas OH⅐ and H 2 O 2 are produced during simulated reperfusion.…”

“…8,9 It is not clear which of the individual isoforms are present in the myocardium, although a JNK1 antibody immunoprecipitates almost all of the 46-kDa activity and a proportion of the 54-kDa activity. 10 Six p38-MAPK isoforms have been cloned: the alternatively spliced p38-MAPK(␣ 1 /␣ 2 ) 11 and p38-MAPK␤ 1 /␤ 2 12 isoforms, p38-MAPK␥, 13,14 and p38-MAPK␦ 15,16 . The levels of p38-MAPK␥ and p38-MAPK␦ transcripts in human heart cDNA libraries are low compared with those of p38-MAPK(␣) and p38-MAPK␤, 16 but it is not yet clear whether these patterns are reflected in the abundances of the proteins.…”

The repression of nuclear factor I/CCAAT transcription factor (NFI/CTF) transactivating domain by oxidative stress is mediated by a critical cysteine (Cys-427)

“…We also investigated the possible role of phosphorylationsensitive residues. Indeed, it has been shown that kinases such as mitogen-activated protein kinase are activated by H # O # [15]. An SPXSP amino acid sequence present in the TAD of NFI\CTF (amino acids 461-465) is similar to the consensus sequence recognized by p38 kinase, as in the CHOP\Gadd153 protein [16].…”