NOD2 pathway via RIPK2 and TBK1 is involved in the aberrant catabolism induced by T-2 toxin in chondrocytes.
OBJECTIVE
This study aimed to identify the key intracellular pattern recognition receptor (PRR) and its role in the unbalanced extracellular matrix gene expressions of chondrocytes treated by T-2 toxin, a potential etiological factor for cartilage damages.


METHODS
Differential expressions of intracellular PRRs after T-2 toxin treatment were screened by RT-qPCR in chondrocytes. RNAi was used to knockdown the expression of NOD2 and its two downstream signal molecules, RIPK2, and TBK1, for observing the effects of NOD2 pathway on regulation of metabolism gene expressions by RT-qPCR. The matrix metalloproteinases (MMP) activity was determined by gelatin zymography. The inhibitor of NF-κB and ROS scavenger were exploited to analyze the mechanism of NOD2 up-regulation in chondrocytes treated with T-2 toxin.


RESULTS
In chondrocytes treated with T-2 toxin, anabolism genes were down-regulated whereas catabolism genes were up-regulated, and NOD2 was identified as a significantly up-regulated gene. Intervening NOD2 expression via RNAi could ameliorate the down-regulation of anabolism genes, while inhibit the up-regulation of catablolism genes induced by T-2 toxin in chondrocytes. RNAi of RIPK2 and TBK1 in chondrocytes could obtain the similar outcome. Furthermore, up-regulation of NOD2 expression induced by T-2 toxin could be abrogated by pretreating the cells with inhibitors of NF-κB and scavenger of ROS.


CONCLUSIONS
T-2 toxin could up-regulate NOD2 expression via ROS/NF-κB pathway and activate NOD2 signaling pathway. The up-regulated NOD2 would affect the metabolism gene expressions and MMP activity in chondrocytes via RIPK2 and TBK1. The findings add new insights into understanding NOD2 effects on chondrocytes treated with T-2 toxin.
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: ccathy0921@gmail.com.
J
J
Xu
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: nana.c.jiang@gmail.com.
C
C
Jiang
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: zwhtdxjtu@gmail.com.
W
W
Zhu
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: realwbo@gmail.com.
B
B
Wang
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: yanjidong@mail.xjtu.edu.cn.
J
J
Yan
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: confident@stu.xjtu.edu.cn.
Z
Z
Min
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: happyeverdayman@163.com.
M
M
Geng
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: hanyan@mail.xjtu.edu.cn.
Y
Y
Han
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: nqlan@mail.xjtu.edu.cn.
Q
Q
Ning
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: ZFJ@mail.xjtu.edu.cn.
F
F
Zhang
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: sunjian1@mail.xjtu.edu.cn.
J
J
Sun
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China. Electronic address: mengliesu@gmail.com.
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L
Meng
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, PR China; Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, PR China. Electronic address: shemin.lu@gmail.com.
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S
Lu
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism*; D015536:Down-Regulation; D005109:Extracellular Matrix / Q000235:genetics; D015870:Gene Expression; D005822:Genetic Vectors; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008660:Metabolism / Q000235:genetics; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D053473:Nod2 Signaling Adaptor Protein / Q000032:analysis / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D034741:RNA, Small Interfering; D051381:Rats; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000502:physiology*; D051192:Receptors, Pattern Recognition / Q000032:analysis* / Q000502:physiology*; D013605:T-2 Toxin / Q000494:pharmacology*; D014161:Transduction, Genetic; D015854:Up-Regulation
D016328:NF-kappa B; C512493:NOD2 protein, rat; D053473:Nod2 Signaling Adaptor Protein; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051192:Receptors, Pattern Recognition; D017346:Protein Serine-Threonine Kinases; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; C403191:TBK1 protein, human; D020782:Matrix Metalloproteinases; D013605:T-2 Toxin
Aberrant catabolism; Chondrocytes; NOD2; T-2 toxin