title: An essential role of Nrf2 in American ginseng-mediated anti-oxidative actions in cardiomyocytes.
abstract: OBJECTIVE
  Ginseng has been used as a folk medicine for thousands of years in Asia, and has become a popular herbal medicine world-wide. Recent studies have revealed that ginseng, including American ginseng, exerts antioxidant effects in the cardiovascular system; however, the underlying mechanisms are not fully understood. Thus, we investigated role of Nrf2, a master transcription factor of endogenous anti-oxidative defense systems, in the regulation of American ginseng-mediated anti-oxidative actions in cardiomyocytes.
  
  
  METHODS
  A standardized crude extract of American ginseng was supplied by the National Research Council of Canada, Institute for National Measurement Standards. H9C2 cells, a rat cardiomyocyte cell line, were exposed to angiotensin II (Ang II) or tumor necrosis factor alpha (TNFalpha) to induce oxidative stress that was examined by measuring formation of reactive oxygen and nitrogen species. Oxidative stress-induced cell death was induced by exogenous addition of hydrogen peroxide (H(2)O(2)). Proteins were measured by Western blot and mRNA expression was determined by quantitative real time PCR. Nrf2-driven transcriptional activity was assessed by antioxidant response element (ARE)-luciferase reporter assay. Direct Nrf2 binding to its target gene promoters was determined by chromatin immunoprecipitation assay. Adenoviral over-expression of Nrf2 shRNA was utilized to knock down Nrf2 in H9C2 cells. Immunochemical staining was applied for Nrf2 expression in the heart.
  
  
  RESULTS
  American ginseng induced dramatic increases in Nrf2 protein expression, Nrf2 nuclear translocation, Nrf2 transcriptional activity, direct Nrf2 binding to its target gene promoters, and expression of a group of anti-oxidative genes driven by Nrf2 in H9C2 cells. In addition, American ginseng inhibited Ang II- or TNFalpha-induced free radical formation and H(2)O(2)-induced cell death in H9C2 cells over-expressed with control shRNA but not in the cells over-expressed with Nrf2 shRNA. Finally, oral administration of American ginseng markedly increased Nrf2 activity in murine hearts.
  
  
  CONCLUSIONS
  These results demonstrate that American ginseng suppresses oxidative stress and oxidative stress-induced cell death in cardiomyocytes through activating the Nrf2 pathway, thereby providing cardioprotection against pathological cardiac remodeling.
authors.affiliation: Department of Cell Biology and Anatomy, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Jinqing
authors.initials: J
authors.lastname: Li
authors.forename: Tomonaga
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.forename: Lorne J
authors.initials: LJ
authors.lastname: Hofseth
authors.forename: Prakash
authors.initials: P
authors.lastname: Nagarkatti
authors.forename: Mitzi
authors.initials: M
authors.lastname: Nagarkatti
authors.forename: Anthony
authors.initials: A
authors.lastname: Windust
authors.forename: Taixing
authors.initials: T
authors.lastname: Cui
mesh_terms: D000284:Administration, Oral; D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D016923:Cell Death; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D005894:Panax; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D034622:RNA Interference; D051381:Rats; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; C495637:Nfe2l2 protein, rat; D016877:Oxidants; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha; D000804:Angiotensin II; D006861:Hydrogen Peroxide
references.citation: PLoS One. 2009 Dec 21;4(12):e8391
references.pmid: 20027226
references.citation: Hypertension. 2007 Feb;49(2):241-8
references.pmid: 17190878
references.citation: Mol Cell Biol. 2009 Jan;29(2):493-502
references.pmid: 19001094
references.citation: Biochim Biophys Acta. 2004 Feb 24;1670(3):165-71
references.pmid: 14980443
references.citation: Hypertension. 2008 Jan;51(1):19-25
references.pmid: 17998475
references.citation: J Ethnopharmacol. 2007 May 22;111(3):567-72
references.pmid: 17374466
references.citation: Cardiovasc Toxicol. 2008 Summer;8(2):71-85
references.pmid: 18463988
references.citation: Eur J Pharmacol. 2006 Feb 27;532(3):201-7
references.pmid: 16497296
references.citation: Circ Res. 2001 May 25;88(10):1088-94
references.pmid: 11375280
references.citation: Clin Exp Pharmacol Physiol. 1996 Aug;23(8):728-32
references.pmid: 8886498
references.citation: Endocrinology. 2008 Aug;149(8):4086-94
references.pmid: 18467446
references.citation: FEBS Lett. 2005 Jun 6;579(14):3029-36
references.pmid: 15896789
references.citation: Circulation. 2004 Jul 20;110(3):309-16
references.pmid: 15226216
references.citation: J Ethnopharmacol. 2007 Jul 25;112(3):568-76
references.pmid: 17590295
references.citation: J Ethnopharmacol. 2009 Aug 17;125(1):145-50
references.pmid: 19505555
references.citation: Eur J Pharmacol. 2004 Jan 19;484(1):1-8
references.pmid: 14729376
references.citation: Acta Pharmacol Sin. 2002 Dec;23(12):1157-62
references.pmid: 12466054
references.citation: Biochem Pharmacol. 1997 Jul 1;54(1):1-8
references.pmid: 9296344
references.citation: FEBS Lett. 1998 Jul 10;431(1):107-10
references.pmid: 9684875
references.citation: Cardiovasc Res. 2004 Aug 15;63(3):433-42
references.pmid: 15276468
references.citation: Mutagenesis. 2005 Jul;20(4):237-43
references.pmid: 15956041
references.citation: Med Sci Monit. 2004 Aug;10(8):RA187-92
references.pmid: 15278009
references.citation: Arterioscler Thromb Vasc Biol. 2009 Nov;29(11):1843-50
references.pmid: 19592468
references.citation: Phytother Res. 2005 Dec;19(12):1018-22
references.pmid: 16372366
references.citation: Am J Chin Med. 2007;35(4):543-58
references.pmid: 17708622
references.citation: FASEB J. 2008 Mar;22(3):659-61
references.pmid: 17942826
references.citation: Curr Vasc Pharmacol. 2009 Jul;7(3):293-302
references.pmid: 19601854
references.citation: Eur J Heart Fail. 2009 Feb;11(2):119-29
references.pmid: 19168509
references.citation: Cardiovasc Res. 2006 Jul 15;71(2):208-15
references.pmid: 16631149
references.citation: Int J Cardiol. 2005 Jan;98(1):1-14
references.pmid: 15676159
references.citation: J Leukoc Biol. 1990 May;47(5):440-8
references.pmid: 2159514
references.citation: Expert Opin Ther Targets. 2009 Jul;13(7):785-94
references.pmid: 19530984
references.citation: Eur J Pharmacol. 2006 Dec 28;553(1-3):209-14
references.pmid: 17092497
references.citation: Am J Physiol Heart Circ Physiol. 2006 Nov;291(5):H2237-45
references.pmid: 16844917
references.citation: J Nutr. 2003 Nov;133(11):3603-9
references.pmid: 14608081
references.citation: Hypertension. 2006 Apr;47(4):791-6
references.pmid: 16520410
references.citation: Circ Res. 2004 Jun 25;94(12):1543-53
references.pmid: 15217919