title: Protective role of the mitochondrial Lon protease 1 in ochratoxin A-induced cytotoxicity in HEK293 cells.
abstract: Ochratoxin A (OTA) is a common kind of mycotoxin and food contaminant, which has various toxicological effects, especially nephrotoxicity. Our previous work about OTA-induced renal cytotoxicity indicated that mitochondrial Lon Protease 1 (Lonp1) might play a protective role. Lonp1 is a multifunctional ATP-dependent protease which mainly participates in mitochondrial proteolysis and protein quality control. The study aimed at probing how Lonp1 functioned in OTA-induced renal cytotoxicity. By means of RNA interference, we down-regulated the expression of Lonp1 in HEK293 cells. Cell viability results revealed that cells with Lonp1 deficiency were more vulnerable to OTA. Then we identified differentially expressed proteins between Lonp1 knock-down cells and scrambled control both in the absence and presence of OTA, using iTRAQ-based quantitative proteomics approach. Thirty-four proteins were differentially expressed as a result of Lonp1 deficiency, while forty-four proteins were differentially expressed in response to both Lonp1 deficiency and OTA treatment. By function summary and pathway analysis, we presumed that Lonp1 realized its protective function in the resistance to OTA-induced renal cytotoxicity via 4 processes: defensing against OTA-induced oxidative stress in the mitochondria; regulating protein synthesis, modification and repair; maintaining the balance of carbohydrate metabolism; and assisting in mtDNA maintenance.
  
  
  CONCLUSIONS
  OTA is a kind of mycotoxin that seriously threatens human health and has various toxicological effects. However, the mechanisms of its toxicity have not been exactly elucidated yet. The method of combination of RNAi and iTRAQ-based quantitative proteomics paves the way to gain a better understanding of the toxicity mechanisms of OTA. The present study, for the first time, verified the protective role of Lonp1 in OTA-induced renal cytotoxicity and clarified the defensive mechanism. Proteomic changes in Lonp1 deficient cells induced by OTA added new knowledge to OTA cytotoxicity.
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Boyang
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China; School of Public Health, Zunyi Medical University, Zunyi, Guizhou 563003, PR China.
authors.forename: Xiao Li
authors.initials: XL
authors.lastname: Shen
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liang
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Yuzhe
authors.initials: Y
authors.lastname: Li
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Kunlun
authors.initials: K
authors.lastname: Huang
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA.
authors.forename: Changhui
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China. Electronic address: xuwentaoboy@sina.com.
authors.forename: Wentao
authors.initials: W
authors.lastname: Xu
mesh_terms: D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D019610:Cytoprotection / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D009183:Mycotoxins / Q000633:toxicity; D009793:Ochratoxins / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D049070:Protease La / Q000502:physiology*; D014162:Transfection
chemical_list: D009183:Mycotoxins; D009793:Ochratoxins; C025589:ochratoxin A; D049070:Protease La
keywords: Lonp1; Ochratoxin A; RNA interference; Renal cytotoxicity; iTRAQ