Carbon monoxide donors or heme oxygenase-1 (HO-1) overexpression blocks interleukin-18-mediated NF-κB–PTEN-dependent human cardiac endothelial cell death

Abstract

The objective of this study was to determine whether heme oxygenase-1 (HO-1) or heme metabolites exert cytoprotective effects on interleukin-18-mediated endothelial cell (EC) death. Treatment with IL-18 increased NF-κB activation, PTEN induction, suppressed Akt activation, and stimulated EC death. While ectopic expression of p65 enhanced PTEN transcription, adenoviral transduction of dnIκB-α, dnp65, or dnIKKβ was inhibitory. Furthermore, IL-18 suppressed HO-1 mRNA expression via enhanced mRNA degradation. Overexpression of HO-1, treatment with HO-1 inducer hemin or the CO donor Cobalt (III) protoporphyrin IX all reversed IL-18-mediated NF-κB activation, PTEN induction, Akt suppression, and EC death. Furthermore, hemin induced HO-1 expression, and HO-1 knockdown, HO-1 inhibition, or CO scavengers all reversed the pro-survival effects of hemin. In addition, the CO donors CORM-1 and CORM-3 and the heme metabolites biliverdin and bilirubin attenuated IL-18-induced EC death via a similar signaling pathway. IL-18 induced p38α MAPK activation, and suppressed p38β isoform expression. While p38α knockdown attenuated, p38β knockdown potentiated IL-18-mediated EC death. Hemin and HO-1 reversed IL-18-mediated p38α induction, and restored p38β levels. These results demonstrate that IL-18 suppresses HO-1 expression and induces EC death. HO-1 overexpression, HO-1 induction, or treatment with heme metabolites all reverse IL-18-mediated p38α MAPK and NF-κB activation, PTEN induction, Akt suppression, and EC death. Thus, HO-1 inducers and CO donors may have the therapeutic potential to effectively block IL-18 signaling and reduce IL-18-dependent vascular injury and inflammation.

Statins exhibit anticancer effects through modifications of the pAkt signaling pathway

“…4A): this may cause nuclear translocation of these pro-apoptotic transcription factors, resulting in the growth arrest and activation of cell death programs. Further, the expression of the transcription factor NFκB, which has been reported to differently modulate PTEN expression in different cell types (6,31,32), was enhanced in the cells under selection with atorvastatin (Fig. 1B).…”

Adiponectin Blocks Interleukin-18-mediated Endothelial Cell Death via APPL1-dependent AMP-activated Protein Kinase (AMPK) Activation and IKK/NF-κB/PTEN Suppression

“…Cell Culture-Nontransformed human cardiac microvascular endothelial cells were obtained from ScienCell Research Laboratories (San Diego, CA) and cultured as described previously (26,27). Briefly, the cells were grown in endothelial cell medium (ECM) supplied by the manufacturer and supplemented with 5% serum (complete medium).…”

“…NF-B Activation-Determination of NF-B activation and its subunit composition in nuclear protein extracts was performed as described previously using a TransAM TM NFB transcription factor ELISA (26). The purity of nuclear extracts was verified by immunoblotting using anti-lamin A/C and tubulin antibodies.…”

“…Transient Transfections and Knockdown-The pPTEN-Luc reporter construct used for these studies has been described previously (26). The transfection efficiency of EC, determined using pEGFP-N1 vector (Clontech-BD Biosciences), was 34.6 Ϯ 2.21% (mean Ϯ S.E., n ϭ 22).…”

Sudden cardiac death in the young: cytokines and pathways

“…The anti-inflammatory properties of HO-1 may rely on its ability to degrade heme and generate bilirubin, free iron and CO, and to reverse IL-18-mediated p38a MAPK and nuclear factor-kB activation, phosphatase and tensin homolog (PTEN) induction, Akt suppression and endothelial cell death (24). HO-1 mRNA upregulation prevents from reperfused VF by promoting endogenous CO formation (21).…”