title: 2,3,5,6-Tetramethylpyrazine (TMP) down-regulated arsenic-induced heme oxygenase-1 and ARS2 expression by inhibiting Nrf2, NF-κB, AP-1 and MAPK pathways in human proximal tubular cells.
abstract: Our recent study demonstrated that sodium arsenite at a clinically relevant dose induced nephrotoxicity in human renal proximal tubular epithelial cell line HK-2, which could be inhibited by natural product 2,3,5,6-tetramethylpyrazine (TMP) with antioxidant activity. The present study demonstrated that arsenic exposure resulted in protein and enzymatic induction of heme oxygenase-1 (HO-1) in dose- and time-dependent manners in HK-2 cells. Blocking HO-1 enzymatic activity by zinc protoporphyrin (ZnPP) augmented arsenic-induced apoptosis, ROS production and mitochondrial dysfunction, suggesting a critical role for HO-1 as a renal protectant in this procession. On the other hand, TMP, upstream of HO-1, inhibited arsenic-induced ROS production and ROS-dependent HO-1 expression. TMP also prevented mitochondria dysfunction and suppressed activation of the intrinsic apoptotic pathway in HK-2 cells. Our results revealed that the regulation of arsenic-induced HO-1 expression was performed through multiple ROS-dependent signal pathways and the corresponding transcription factors, including p38 MAPK and JNK (but not ERK), AP-1, Nrf2 and NF-κB. TMP inhibited arsenic-induced activations of JNK, p38 MAPK, ERK, AP-1 and Nrf2 and block HO-1 protein expression. The present study, furthermore, demonstrated arsenic-induced expression of arsenic response protein 2 (ARS2) that was regulated by p38 MAPK, ERK and NF-κB. To our knowledge, this is the first report showing that ARS2 involved in arsenic-induced nephrotoxicity, while TMP pretreatment prevented such an up-regulation of ARS2 in HK-2 cells. Given ARS2 and HO-1 sharing the similar regulation mechanism, we speculated that ARS2 might also mediate cell survival in this procession. In summary, our study highlighted a role of HO-1 in the protection against arsenic-induced cytotoxicity downstream from the primary targets of TMP and further indicated that TMP may be used as a potential therapeutic agent in the treatment of arsenic-induced nephrotoxicity.
authors.affiliation: Department of Nephrology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 274 Zhijiang Middle Road, Shanghai, 200071, China. shnanshan@hotmail.com.|Center for Radiological Research, College of Physician and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA. shnanshan@hotmail.com.
authors.forename: Xuezhong
authors.initials: X
authors.lastname: Gong
authors.affiliation: Center for Radiological Research, College of Physician and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Ivanov
authors.affiliation: Center for Radiological Research, College of Physician and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA.|Department of Radiation Oncology, College of Physician and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA.
authors.forename: Tom K
authors.initials: TK
authors.lastname: Hei
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D018053:Arsenites / Q000633:toxicity*; D002460:Cell Line; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011719:Pyrazines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D017670:Sodium Compounds / Q000633:toxicity*; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D018053:Arsenites; D004791:Enzyme Inhibitors; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; C495635:NFE2L2 protein, human; D009687:Nuclear Proteins; D011719:Pyrazines; D017382:Reactive Oxygen Species; C527299:SRRT protein, human; D017670:Sodium Compounds; D018808:Transcription Factor AP-1; C017947:sodium arsenite; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1; D020928:Mitogen-Activated Protein Kinases; C017953:tetramethylpyrazine
keywords: Arsenic response protein 2 (ARS2); Inducible heme oxygenase-1 (HO-1); Mitochondrial dysfunction; Nephrotoxicity; Nuclear factor erythroid derived-2 (Nrf2); Sodium arsenite; Tetramethylpyrazine (TMP)