Induction of heme oxygenase-1 (HO-1) and NAD[P]H: quinone oxidoreductase 1 (NQO1) by a phenolic antioxidant, butylated hydroxyanisole (BHA) and its metabolite, tert-butylhydroquinone (tBHQ) in primary-cultured human and rat hepatocytes.
OBJECTIVE
This study was aimed to investigate the effects of a phenolic antioxidant, butylated hydroxyanisole (BHA) and its metabolite, tert-butylhydroquinone (tBHQ) on the induction of HO-1, NQO1 and Nrf2 proteins and their regulatory mechanisms in primary-cultured hepatocytes.


METHODS
After exposure of BHA and tBHQ to primary-cultured rat and human hepatocytes and mouse neonatal fibroblasts (MFs), Western blot, semi-quantitative RT-PCR and microarray analysis were conducted.


RESULTS
Induction of HO-1, NQO1 and Nrf2 proteins and activation of ERK1/2 and JNK1/2 were observed after BHA and tBHQ treatments in primary-cultured rat and human hepatocytes. Semi-quantitative RT-PCR study and microarray analysis revealed that HO-1 and NQO1 were transcriptionally activated in primary-cultured rat hepatocytes and a substantial transcriptional activation, including HO-1 occurred in primary-cultured human hepatocytes after BHA treatment. Whereas BHA failed to induce HO-1 in wild-type and Nrf2 knock-out MFs, tBHQ strongly induced HO-1 in wild-type, but not in Nrf2 knock-out MFs.


CONCLUSIONS
Our data demonstrate that both BHA and tBHQ are strong chemical inducers of HO-1, NQO1 and Nrf2 proteins in primary-cultured human and rat hepatocytes with the activation of MAPK ERK1/2 and JNK1/2. However, in MFs, BHA failed to induce HO-1, whereas tBHQ strongly induced HO-1 in Nrf2 wild-type but not in Nrf2 knock-out, suggesting that Nrf2 is indispensable for tBHQ-induced HO-1 in MF.
Keum
Young-Sam
YS
Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
Han
Yong-Hae
YH
Liew
Celine
C
Kim
Jung-Hwan
JH
Xu
Changjiang
C
Yuan
Xiaoling
X
Shakarjian
Michael P
MP
Chong
Saeho
S
Kong
Ah-Ng
AN
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002083:Butylated Hydroxyanisole / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000096:biosynthesis* / Q000235:genetics; D022781:Hepatocytes / Q000201:enzymology*; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis* / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000975:Antioxidants; D006873:Hydroquinones; D051267:NF-E2-Related Factor 2; D002083:Butylated Hydroxyanisole; C018855:2-tert-butylhydroquinone; D051547:Heme Oxygenase-1; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; C507703:NQO1 protein, rat; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases