Heme oxygenase-1 (HO-1) has been suggested to be a key neuroprotective enzyme because of its widespread distribution in the brain as well as its strong antioxidative effects. HX106N, a water-soluble botanical formulation, has previously been demonstrated to prevent amyloid β-induced memory impairment and oxidative stress in mice by upregulating HO-1 levels. In this study, the underlying molecular mechanisms of HX106N-induced HO-1 expression were investigated using BV-2 cells, a murine microglial cell line, and primary microglia. Treatment with HX106N induced the expression of HO-1 at the transcriptional level through the stress-responsive element-containing enhancer present in the ho-1 promoter. Nuclear factor E2-related factor 2 (Nrf2) was activated in cells treated with HX106N. The results from knockdown assay showed that small interfering RNA of Nrf2 attenuated HX106N-mediated HO-1 expression. Pharmacological inhibitors of p38 and JNK mitogen-activated protein kinases suppressed the HX106N-mediated induction of HO-1. The NF-κB signaling pathway was activated by HX106N and played a role in HX106N-induced HO-1 expression. Furthermore, HO-1 and one of its by-products during the enzymatic degradation of heme, CO, were found to be involved in HX106N-mediated suppression of NO production. Taken together, these data indicate that HX106N exerts potent antioxidative effects by increasing the expression of HO-1 through multiple signaling pathways, leading to the suppression of NO production.
SchipperHMStopaEG. Expression of heme oxygenase-1 in the senescent and Alzheimer-diseased brain. Ann Neurol1995; 37: 758–68.
2.
CastellaniRSmithMARicheyPLPerryG. Glycoxidation and oxidative stress in Parkinson disease and diffuse Lewy body disease. Brain Res1996; 737: 195–200.
3.
CalingasanNYChenJKiaeiMBealMF. Beta-amyloid 42 accumulation in the lumbar spinal cord motor neurons of amyotrophic lateral sclerosis patients. Neurobiol Dis2005; 19: 340–7.
4.
BeschornerRAdjodahDSchwabJMMittelbronnMPedalIMatternRSchluesenerHJMeyermannR. Long-term expression of heme oxygenase-1 (HO-1, HSP-32) following focal cerebral infarctions and traumatic brain injury in humans. Acta Neuropathol2000; 100: 377–84.
5.
TenhunenRMarverHSSchmidR. Enzymatic conversion of heme to bilirubin by microsomal heme oxygenase. Proc Natl Acad Sci USA1968; 61: 748–55.
6.
StockerRYamamotoYMcdonaghAFGlazerANAmesBN. Bilirubin is an antioxidant of possible physiological importance. Science1987; 235: 1043–6.
7.
DoreSTakahashiMFerrisCDZakharyRHesterLDGuastellaDSnyderSH. Bilirubin, formed by activation of heme oxygenase-2, protects neurons against oxidative stress injury. Proc Natl Acad Sci USA1999; 96: 2445–50–2445–50.
8.
OtterbeinLEBachFHAlamJSoaresMLuHTWyskMDavisRJFlavellRAChoiAMK. Carbon monoxide has anti-inflammatory effects involving the mitogen-activated protein kinase pathway. Nat Med2000; 6: 422–8.
9.
BallaGJacobHSBallaJRosenbergMNathKAppleFEatonJWVercellottiGM. Ferritin: a cytoprotective antioxidant strategem of endothelium. J Biol Chem1992; 267: 18148–53.
10.
ChoiJLeeJKimSHKimJKimS. PG201 downregulates the production of nitrite by upregulating heme oxygenase-1 expression through the control of phosphatidylinositol 3-kinase and NF-E2-related factor 2. Nitric Oxide2013; 33: 42–55.
11.
PanahianNYoshiuraMMainesMD. Overexpression of heme oxygenase-1 is neuroprotective in a model of permanent middle cerebral artery occlusion in transgenic mice. J Neurochem1999; 72: 1187–203.
LeWXieWAppelSH. Protective role of heme oxygenase-1 in oxidative stress-induced neuronal injury. J Neurosci Res1999; 56: 652–8.
14.
CuadradoARojoAI. Heme oxygenase-1 as a therapeutic target in neurodegenerative diseases and brain infections. Curr Pharm Design2008; 14: 429–42.
15.
RyterSWAlamJChoiAM. Heme oxygenase-1/carbon monoxide: from basic science to therapeutic applications. Physiol Rev2006; 86: 583–650.
16.
AlamJStewartDTouchardCBoinapallySChoiAMCookJL. Nrf2, a Cap’n’Collar transcription factor, regulates induction of the heme oxygenase-1 gene. J Biol Chem1999; 274: 26071–8.
17.
AlamJCookJL. Transcriptional regulation of the heme oxygenase-1 gene via the stress response element pathway. Curr Pharm Design2003; 9: 2499–511.
18.
AlamJDenZ. Distal AP-1 binding sites mediate basal level enhancement and TPA induction of the mouse heme oxygenase-1 gene. J Biol Chem1992; 267: 21894–900.
19.
AlamJCookJL. How many transcription factors does it take to turn on the heme oxygenase-1 gene?Am J Resp Cell Mol2007; 36: 166–74.
20.
LuDYTsaoYYLeungYMSuKP. Docosahexaenoic acid suppresses neuroinflammatory responses and induces heme oxygenase-1 expression in BV-2 microglia: implications of antidepressant effects for omega-3 fatty acids. Neuropsychopharmacol2010; 35: 2238–48.
21.
Hill-KapturczakNThamilselvanVLiuFYNickHSAgarwalA. Mechanism of heme oxygenase-1 gene induction by curcumin in human renal proximal tubule cells. Am J Physiol-Renal2001; 281: F851–F9.
22.
JuanSHChengTHLinHCChuYLLeeWS. Mechanism of concentration-dependent induction of heme oxygenase-1 by resveratrol in human aortic smooth muscle cells. Biochem Pharmacol2005; 69: 41–8.
23.
LeeDSChoiJKimSHKimS. Ameliorating effects of HX106N, a water-soluble botanical formulation, on Abeta25-35-induced memory impairment and oxidative stress in mice. Biol Pharm Bull2014; 37: 954–60.
24.
SauraJTusellJMSerratosaJ. High-yield isolation of murine microglia by mild trypsinization. Glia2003; 44: 183–9.
25.
AlamJCaiJSmithA. Isolation and characterization of the mouse heme oxygenase-1 gene. Distal 5′ sequences are required for induction by heme or heavy metals. J Biol Chem1994; 269: 1001–9.
26.
AlamJCamhiSChoiAM. Identification of a second region upstream of the mouse heme oxygenase-1 gene that functions as a basal level and inducer-dependent transcription enhancer. J Biol Chem1995; 270: 11977–84.
27.
BalogunEHoqueMGongPKilleenEGreenCJForestiRAlamJMotterliniR. Curcumin activates the haem oxygenase-1 gene via regulation of Nrf2 and the antioxidant-responsive element. Biochem J2003; 371: 887–95.
28.
CamhiSLAlamJOtterbeinLSylvesterSLChoiAM. Induction of heme oxygenase-1 gene expression by lipopolysaccharide is mediated by AP-1 activation. Am J Respir Cell Mol Biol1995; 13: 387–98.
29.
DrechslerYDolganiucANorkinaORomicsLLiWKodysKBachFHMandrekarPSzaboG. Heme oxygenase-1 mediates the anti-inflammatory effects of acute alcohol on IL-10 induction involving p38 MAPK activation in monocytes. J Immunol2006; 177: 2592–600.
30.
ImmenschuhSRamadoriG. Gene regulation of heme oxygenase-1 as a therapeutic target. Biochem Pharmacol2000; 60: 1121–8.
31.
RyterSWXiSHartsfieldCLChoiAM. Mitogen activated protein kinase (MAPK) pathway regulates heme oxygenase-1 gene expression by hypoxia in vascular cells. Antioxid Redox Signal2002; 4: 587–92.
32.
BrownGCBal-PriceA. Inflammatory neurodegeneration mediated by nitric oxide, glutamate, and mitochondria. Mol Neurobiol2003; 27: 325–55.
33.
WangWWSmithDLZuckerSD. Bilirubin inhibits iNOS expression and NO production in response to endotoxin in rats. Hepatology2004; 40: 424–33.
34.
SrisookKChaYN. Super-induction of HO-1 in macrophages stimulated with lipopolysaccharide by prior depletion of glutathione decreases iNOS expression and NO production. Nitric Oxide2005; 12: 70–9.
35.
SawlePForestiRMannBEJohnsonTRGreenCJMotterliniR. Carbon monoxide-releasing molecules (CO-RMs) attenuate the inflammatory response elicited by lipopolysaccharide in RAW264.7 murine macrophages. Brit J Pharmacol2005; 145: 800–10.
36.
WhiteKAMarlettaMA. Nitric-oxide synthase is a cytochrome-P-450 type hemoprotein. Biochemistry-Us1992; 31: 6627–31.
37.
SteppanJRyooSSchuleriKHGreggCHasanRKWhiteARBugajLJKhanMSanthanamLNyhanDShoukasAAHareJMBerkowitzDE. Arginase modulates myocardial contractility by a nitric oxide synthase 1-dependent mechanism. Proc Natl Acad Sci USA2006; 103: 4759–64.
SurhYJKunduJKNaHK. Nrf2 as a master redox switch in turning on the cellular signaling involved in the induction of cytoprotective genes by some chemopreventive phytochemicals. Planta Med2008; 74: 1526–39.
40.
NaHKSurhYJ. Transcriptional regulation via cysteine thiol modification: a novel molecular strategy for chemoprevention and cytoprotection. Mol Carcinogen2006; 45: 368–80.
41.
Dinkova-KostovaATTalalayP. Direct and indirect antioxidant properties of inducers of cytoprotective proteins. Mol Nutr Food Res2008; 52: S128–38.
42.
ParkJLiuAY. JNK phosphorylates the HSF1 transcriptional activation domain: role of JNK in the regulation of the heat shock response. J Cell Biochem2001; 82: 326–38.
43.
LeePJCamhiSLChinBYAlamJChoiAM. AP-1 and STAT mediate hyperoxia-induced gene transcription of heme oxygenase-1. Am J Physiol Lung Cell Mol Physiol2000; 279: L175–82.
44.
LeeSAKimEYJeonWKWooCHChoeJHanSKimBC. The inhibitory effect of raloxifene on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells is mediated through a ROS/p38 MAPK/CREB pathway to the up-regulation of heme oxygenase-1 independent of estrogen receptor. Biochimie2011; 93: 168–74.
45.
CarterABKnudtsonKLMonickMMHunninghakeGW. The p38 mitogen-activated protein kinase is required for NF-kappaB-dependent gene expression. The role of TATA-binding protein (TBP). J Biol Chem1999; 274: 30858–63.
46.
LeeDSJeoungJGKimS. Effects of HX106N, a water-soluble botanical formulation on scopolamine-induced memory impairment in mice. Korean J Food Nutr2014; 27: 673–77.
