N-n-Butyl Haloperidol Iodide Ameliorates Cardiomyocytes Hypoxia/Reoxygenation Injury by Extracellular Calcium-Dependent and -Independent Mechanisms

Abstract

N-n-butyl haloperidol iodide (F2) has been shown to antagonize myocardial ischemia/reperfusion injury by blocking calcium channels. This study explores the biological functions of ERK pathway in cardiomyocytes hypoxia/reoxygenation injury and clarifies the mechanisms by which F2 ameliorates cardiomyocytes hypoxia/reoxygenation injury through the extracellular-calcium-dependent and -independent ERK1/2-related pathways. In extracellularcalcium-containing hypoxia/reoxygenation cardiomyocytes, PKCα and ERK1/2 were activated, Egr-1 protein level and cTnI leakage increased, and cell viability decreased. The ERK1/2 inhibitors suppressed extracellular-calcium-containing-hypoxia/reoxygenation-induced Egr-1 overexpression and cardiomyocytes injury. PKCα inhibitor downregulated extracellularcalcium-containing-hypoxia/reoxygenation-induced increase in p-ERK1/2 and Egr-1 expression. F2 downregulated hypoxia/reoxygenation-induced elevation of p-PKCα, p-ERK1/2, and Egr-1 expression and inhibited cardiomyocytes damage. The ERK1/2 and PKCα activators antagonized F2's effects. In extracellular-calcium-free-hypoxia/reoxygenation cardiomyocytes, ERK1/2 was activated, LDH and cTnI leakage increased, and cell viability decreased. F2 and ERK1/2 inhibitors antagonized extracellular-calcium-free-hypoxia/reoxygenation-induced ERK1/2 activation and suppressed cardiomyocytes damage. The ERK1/2 activator antagonized F2's above effects. F2 had no effect on cardiomyocyte cAMP content or PKA and Egr-1 expression. Altogether, ERK activation in extracellular-calcium-containing and extracellular-calcium-free hypoxia/reoxygenation leads to cardiomyocytes damage. F2 may ameliorate cardiomyocytes hypoxia/reoxygenation injury by regulating the extracellular-calcium-dependent PKCα/ERK1/2/Egr-1 pathway and through the extracellular-calcium-independent ERK1/2 activation independently of the cAMP/PKA pathway or Egr-1 overexpression.

N-n-butyl Haloperidol Iodide Protects against Hypoxia/Reoxygenation Injury in Cardiac Microvascular Endothelial Cells by Regulating the ROS/MAPK/Egr-1 Pathway

“…Previous studies on cardiomyocytes revealed that ERK1/2 also mediates Egr-1-dependent H/R injury (Zhang et al, 2013). Although some studies proposed that JNK and ERK1/2 are the chief upstream signals of Egr-1-mediated lung I/R injury or pulmonary alveolar macrophage H/R injury (Fujita et al, 2004; Yamamoto et al, 2011), p38 also has been shown to contribute to H/R injury in human umbilical vein endothelial cells (Millar et al, 2007).…”

“…Extensive studies demonstrate that MAPKs (ERK1/2, JNK, p38) are involved in I/R injury. We previously demonstrated that JNK and ERK1/2 mediate Egr-1 induction during H/R injury in H9c2 cells and primary cardiomyocytes, respectively, with ROS/Egr-1 signaling participating in the former (Zhang et al, 2013, 2015). It remains unknown whether MAPK is activated by H/R stimuli in CMECs, and whether the other two MAPK pathways, besides JNK, are involved in CMEC ROS/Egr-1 signaling.…”

“…F 2 could protect against H/R injury in CMECs, as well as H9c2 cells, by decreasing oxidative stress and inhibiting the expression of Egr-1 (Zhou et al, 2010b). Furthermore, F 2 alleviates H/R injury by reducing the activation of JNK and ERK1/2 responsible for Egr-1 induction in H9c2 cells and primary cardiomyocytes following H/R (Zhou et al, 2010b; Zhang et al, 2013). The above data suggest that the protective effect of F 2 on CMECs could be related to an ability to inhibit the ROS/MAPK/Egr-1 pathway.…”

Effect of N-n-butyl haloperidol iodide on ROS/JNK/Egr-1 signaling in H9c2 cells after hypoxia/reoxygenation

“…Extensive research studying the efficacy and mechanism of action of F 2 revealed that F 2 could improve I/R or hypoxia/reoxygenation (H/R)-induced myocardial tissue or myocardial cell damage by blocking membrane L-type Ca 2 + channels and inhibiting Egr-1 overexpression. Classic calcium antagonists also inhibit the expression of Egr-1, suggesting that the F 2 -mediated inhibition of Egr-1 expression might be related to its inhibition of Ca 2+ 10 12 13 14 . In addition, we found that F 2 could antagonize I/R- or H/R-induced decreased SOD activity and increased malondialdehyde (MDA; an oxidative stress product) level, which suggested that F 2 might play a negative regulatory role in abnormal ROS generation during myocardial I/R or H/R 15 .…”

Ulinastatin ameliorates LPS‑induced pulmonary inflammation and injury by blocking the MAPK/NF‑κB signaling pathways in rats

“…A previous study demonstrated that NF-κB is activated via MAPKs, including SAPK/JNK, p38 MAPK and eRK1/2. MaPKs are considered to be evolutionarily conserved and respond to stress by activating signal transduction during a phosphorylation cascade from cytoplasmic to nuclear targets (55,56).…”