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  2. Microcystin-leucine-arginine causes blood-testis barrier disruption and degradation of occludin mediated by matrix metalloproteinase-8

Microcystin-leucine-arginine causes blood-testis barrier disruption and degradation of occludin mediated by matrix metalloproteinase-8

  • Cell Mol Life Sci. 2018 Mar;75(6):1117-1132. doi: 10.1007/s00018-017-2687-6.
Yabing Chen 1 2 Jing Wang 1 2 Chun Pan 1 2 Dongmei Li 3 4 Xiaodong Han 5 6
Affiliations

Affiliations

  • 1 Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, 210093, China.
  • 2 Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, 210093, China.
  • 3 Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, 210093, China. lidm@nju.edu.cn.
  • 4 Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, 210093, China. lidm@nju.edu.cn.
  • 5 Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, 210093, China. hanxd@nju.edu.cn.
  • 6 Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, 210093, China. hanxd@nju.edu.cn.
Abstract

Microcystin-leucine-arginine (MC-LR) can cause male reproductive disorders. However, the underlying mechanisms are not yet fully understood. In this study, we aimed to investigate the effects of MC-LR on the integrity of blood-testis barrier (BTB) and the related molecular mechanisms. Both transepithelial electrical resistance measurement in vitro and electron microscope observation ex vivo revealed that MC-LR caused disruption of the tight junction between Sertoli cells, which was paralleled by the degradation of occludin. We observed increased expression of matrix metalloproteinase-8 (MMP-8) upon exposure to MC-LR, and confirmed that abrogation of MMP-8 activity by specific inhibitors as well as transfection with MMP-8 shRNA could abolish the degradation of occludin. Our data demonstrated that MC-LR up-regulated nuclear levels of c-Fos and c-Jun through activating ERK and JNK, and increased NF-κB levels by activating the phosphatidylinositol 3-kinase (PI3K)/Akt cascades. Enhanced binding of c-Fos and NF-κB to the promoter of MMP-8 promoted the transcription of MMP-8 gene. Furthermore, miR-184-3p was significantly downregulated in SC following exposure to MC-LR through targeting MMP-8 expression. Together, these results confirmed that MC-LR-induced MMP-8 expression was regulated at both transcriptional and post-transcriptional levels, which was involved in MC-LR-induced degradation of occludin and BTB destruction. This work may provide new perspectives in developing new diagnosis and treatment strategies for MC-induced male infertility.

Keywords

MMP-8; Microcystin–leucine–arginine; Occludin degradation; Transcriptional and post-transcriptional levels.

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