title: Transcription factor Nrf2 is essential for induction of NAD(P)H:quinone oxidoreductase 1, glutathione S-transferases, and glutamate cysteine ligase by broccoli seeds and isothiocyanates.
abstract: Cruciferous vegetables contain glucosinolates that, after conversion to isothiocyanates (ITC), are capable of inducing cytoprotective genes. We examined whether broccoli seeds can elicit a chemoprotective response in mouse organs and rodent cell lines and investigated whether this response requires nuclear factor-erythroid 2 p45-related factor 2 (Nrf2). The seeds studied contained glucosinolate at 40 mmol/kg, of which 59% comprised glucoiberin, 19% sinigrin, 8% glucoraphanin, and 7% progoitrin. Dietary administration of broccoli seeds to nrf2(+/+) and nrf2(-/-) mice produced a approximately 1.5-fold increase in NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) activities in stomach, small intestine, and liver of wild-type mice but not in mutant mice; increased transferase activity was associated with elevated levels of GSTA1/2, GSTA3, and GSTM1/2 subunits. These seeds also increased significantly the level of glutamate cysteine ligase catalytic (GCLC) subunit in the stomach and the small intestine of nrf2(+/+) mice but not nrf2(-/-) mice. An aqueous broccoli seed extract was prepared for treatment of cultured cells that contained ITC at approximately 600 mumol/L, composed of 61% 3-methylsulfinylpropyl ITC, 30% sulforaphane, 4% allyl ITC, and 4% 3-butenyl ITC. This extract induced GSTA1/2, GSTA3, NQO1, and GCLC between 3-fold and 10-fold in mouse Hepa-1c1c7 and rat liver RL-34 cells. The broccoli seed extract affected increases in GSTA3, GSTM1, and NQO1 proteins in nrf2(+/+) mouse embryonic fibroblasts but not in nrf2(-/-) mouse embryonic fibroblasts. These experiments show that broccoli seeds are effective at inducing antioxidant and detoxication proteins, both in vivo and ex vivo, in an Nrf2-dependent manner.
authors.affiliation: Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom.
authors.forename: Gail K
authors.initials: GK
authors.lastname: McWalter
authors.forename: Larry G
authors.initials: LG
authors.lastname: Higgins
authors.forename: Lesley I
authors.initials: LI
authors.lastname: McLellan
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Henderson
authors.forename: Lijiang
authors.initials: L
authors.lastname: Song
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Thornalley
authors.forename: Ken
authors.initials: K
authors.lastname: Itoh
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: John D
authors.initials: JD
authors.lastname: Hayes
mesh_terms: D000818:Animals; D001937:Brassica / Q000737:chemistry*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004032:Diet; D004790:Enzyme Induction / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D005961:Glucosinolates / Q000032:analysis / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase / Q000096:biosynthesis*; D005982:Glutathione Transferase / Q000096:biosynthesis*; D007421:Intestine, Small / Q000201:enzymology; D017879:Isothiocyanates / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis*; D051267:NF-E2-Related Factor 2; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry; D013270:Stomach / Q000201:enzymology; D015534:Trans-Activators / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D005961:Glucosinolates; D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D010936:Plant Extracts; D015534:Trans-Activators; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D005982:Glutathione Transferase; D005721:Glutamate-Cysteine Ligase