title: HMG-CoA reductase inhibitors upregulate heme oxygenase-1 expression in murine RAW264.7 macrophages via ERK, p38 MAPK and protein kinase G pathways.
abstract: Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in heme catabolism, which confers cytoprotection against oxidative injury and provides a vital function in maintaining tissue homeostasis. HMG-CoA reductase inhibitors (statins) possess several anti-inflammatory mechanisms and may be beneficial in the treatment of inflammatory diseases. Our previous study has shown that statins can inhibit iNOS gene expression in murine RAW264.7 macrophages. In this study, we showed that lovastatin, fluvastatin, atorvastatin, simvastatin, mevastatin and pravastatin are able to upregulate the mRNA expression of HO-1 gene. This effect of lovastatin was attenuated by farnesyl pyrophosphate (FPP), geranylgeranyl pyrophosphate (GGPP), a protein kinase G (PKG) inhibitor (KT5823), a soluble guanylyl cyclase inhibitor (ODQ), a p38 MAPK inhibitor (SB203580), and MEK inhibitors (U0126 and PD98059), but not by inhibitors of protein kinase C (PKC), protein kinase A (PKA), c-jun N-terminal kinase (JNK) and Rho kinase. Consistent with this notion, our previous study has reported the ability of statins to activate ERK and p38 MAPK in RAW264.7 macrophages. Here we further found the participation of cyclic guanosine monophosphate (cGMP)/PKG pathway for ERK activation in cells stimulated with statin and the ability of statin to induce AP-1 activity, which is an essential transcription factor in the regulation of HO-1 gene expression. In addition, a Ras inhibitor (manumycin A) treatment also caused a marked induction of HO-1 mRNA followed by a corresponding increase in HO-1 protein; instead, inhibition of Rho activity by toxin B only led to a transient and weak induction of HO-1. The involvement of signal pathways in manumycin A-induced HO-1 gene expression was associated with p38 MAPK, JNK and ERK activation. Taken together, these results demonstrate for the first time that statins might activate PKG to elicit activations of ERK and p38 MAPK pathways and finally induce HO-1 gene expression, which provides a novel anti-inflammatory mechanism in the therapeutic validity.
authors.affiliation: Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Jui-Ching
authors.initials: JC
authors.lastname: Chen
authors.forename: Kuo-Chin
authors.initials: KC
authors.lastname: Huang
authors.forename: Wan-Wan
authors.initials: WW
authors.lastname: Lin
mesh_terms: D000818:Animals; D002460:Cell Line; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D011090:Polyenes / Q000494:pharmacology; D053284:Polyunsaturated Alkamides; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D018631:ras Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011090:Polyenes; D053284:Polyunsaturated Alkamides; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D051547:Heme Oxygenase-1; D017869:Cyclic GMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; D006152:Cyclic GMP; C054474:manumycin