Andrographolide inhibits hypoxia-induced HIF-1α-driven endothelin 1 secretion by activating Nrf2/HO-1 and promoting the expression of prolyl hydroxylases 2/3 in human endothelial cells.
Andrographolide, the main bioactive component of the medicinal plant Andrographis paniculata, has been shown to possess potent anti-inflammatory activity. Endothelin 1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, displays proinflammatory property. Hypoxia-inducible factor 1α (HIF-1α), the regulatory member of the transcription factor heterodimer HIF-1α/β, is one of the most important molecules that responds to hypoxia. Changes in cellular HIF-1α protein level are the result of altered gene transcription and protein stability, with the latter being dependent on prolyl hydroxylases (PHDs). In this study, inhibition of pro-inflammatory ET-1 expression and changes of HIF-1α gene transcription and protein stability under hypoxia by andrographolide in EA.hy926 endothelial-like cells were investigated. Hypoxic conditions were created using the hypoxia-mimetic agent CoCl2.We found that hypoxia stimulated the production of reactive oxygen species (ROS), the expression of HIF-1α mRNA and protein, and the expression and secretion of ET-1. These effects, however, were attenuated by co-exposure to andrographolide, bilirubin, and RuCO. Silencing Nrf2 and heme oxygenase 1 (HO-1) reversed the inhibitory effects of andrographolide on hypxoia-induced HIF-1α mRNA and protein expression. Moreover, andrographolide increased the expression of prolyl hydroxylases (PHD) 2/3, which hydroxylate HIF-1α and promotes HIF-1α proteasome degradation, with an increase in HIF-1α hydroxylation was noted under hypoxia. Inhibition of p38 MAPK abrogated the hypoxia-induced increases in HIF-1α mRNA and protein expression as well as ET-1 mRNA expression and secretion. Taken together, these results suggest that andrographolide suppresses hypoxia-induced pro-inflammatory ET-1 expression by activating Nrf2/HO-1, inhibiting p38 MAPK signaling, and promoting PHD2/3 expression. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 918-930, 2017.
Division of Neonatology, College of Medicine and Department of Pediatrics, Children's Hospital of China Medical University and China Medical University Hospital, Taichung, Taiwan.
Hung-Chih
HC
Lin
Changhua Christian Hospital, Vascular and Genomic Center, Changhua, Taiwan.|Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.|Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Shih-Li
SL
Su
Department of Nutrition, China Medical University, Taichung, Taiwan.
Chia-Yang
CY
Lu
Department of Nutrition, China Medical University, Taichung, Taiwan.
Ai-Hsuan
AH
Lin
Department of Nutrition, China Medical University, Taichung, Taiwan.
Wan-Chun
WC
Lin
Changhua Christian Hospital, Vascular and Genomic Center, Changhua, Taiwan.|Department of Neurology, Changhua Christian Hospital, Changhua, Taiwan.
Chin-San
CS
Liu
Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
Ya-Chen
YC
Yang
Department of Nutrition, China Medical University, Taichung, Taiwan.
Hsiu-Miao
HM
Wang
Department of Nutrition, China Medical University, Taichung, Taiwan.|Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
Chong-Kuei
CK
Lii
Department of Nutrition, China Medical University, Taichung, Taiwan.
Haw-Wen
HW
Chen
D015687:Cell Hypoxia; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003035:Cobalt / Q000633:toxicity; D004224:Diterpenes / Q000494:pharmacology*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006900:Hydroxylation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D064828:Prolyl Hydroxylases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D004224:Diterpenes; D019332:Endothelin-1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D003035:Cobalt; C030419:andrographolide; D064828:Prolyl Hydroxylases; D051547:Heme Oxygenase-1; D048051:p38 Mitogen-Activated Protein Kinases; C018021:cobaltous chloride
Nrf2; andrographolide; endothelin 1 (ET-1); heme oxygenase 1 (HO-1); hypoxia-inducible factor 1α (HIF-1α); prolyl hydroxylases (PHDs)