Protective role of the mitochondrial Lon protease 1 in ochratoxin A-induced cytotoxicity in HEK293 cells

Boyang Zhang; Xiao Li Shen; Rui Liang; Yuzhe Li; Kunlun Huang; Changhui Zhao; Yunbo Luo; Wentao Xu

doi:10.1016/j.jprot.2014.02.017

Protective role of the mitochondrial Lon protease 1 in ochratoxin A-induced cytotoxicity in HEK293 cells

J Proteomics. 2014 Apr 14:101:154-68. doi: 10.1016/j.jprot.2014.02.017. Epub 2014 Feb 22.

Authors

Boyang Zhang¹, Xiao Li Shen², Rui Liang¹, Yuzhe Li¹, Kunlun Huang¹, Changhui Zhao³, Yunbo Luo¹, Wentao Xu⁴

Affiliations

¹ Laboratory of food safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
² 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.
³ Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA.
⁴ 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.

PMID: 24565693
DOI: 10.1016/j.jprot.2014.02.017

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.

Biological significance: 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.

Keywords: Lonp1; Ochratoxin A; RNA interference; Renal cytotoxicity; iTRAQ.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cell Survival / drug effects
Cell Survival / genetics
Cytoprotection / genetics*
HEK293 Cells
Humans
Kidney / drug effects*
Kidney / metabolism
Kidney / pathology
Mitochondria / enzymology*
Mitochondria / genetics
Mycotoxins / toxicity
Ochratoxins / toxicity*
Oxidative Stress / drug effects
Oxidative Stress / genetics
Protease La / physiology*
Transfection

Substances

Mycotoxins
Ochratoxins
ochratoxin A
Protease La