Basic Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Stem Cells. Jun 26, 2020; 12(6): 500-513
Published online Jun 26, 2020. doi: 10.4252/wjsc.v12.i6.500
Cytotoxicity of nonylphenol on spermatogonial stem cells via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway
Jun-Hao Lei, Wen Yan, Chun-Hua Luo, Yu-Ming Guo, Yang-Yang Zhang, Xing-Huan Wang, Xin-Jun Su
Jun-Hao Lei, Chun-Hua Luo, Yu-Ming Guo, Yang-Yang Zhang, Xing-Huan Wang, Xin-Jun Su, Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, Hubei Province, China
Wen Yan, Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, Hubei Province, China
Xing-Huan Wang, Center for Evidence-based and Translational Medicine, Wuhan University, Wuhan 430071, Hubei Province, China
Author contributions: Guo YM, Zhang YY and Yan W collected and analyzed the data; Lei JH and Luo CH drafted the manuscript; Su XJ and Wang XH commented in detail on the manuscript; All authors read and approved the final manuscript.
Supported by Health and Family Planning Committee Joint Fund Project of Hubei Province, No. WJ2018H0020; Fundamental Research Funds for the Central Universities, No. 2042016kf0187 and No. 2042017kf0068; and Zhongnan Hospital of Wuhan University Science, Technology and Innovation Seed Fund, No. znpy2016022.
Institutional animal care and use committee statement: All animal experiments conformed to the Guidelines for Animal Care and Use of the Model Animal Research Institute at Wuhan Myhalic Biotechnology Co., Ltd. (approval No. HLK-20180522-01).
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Xin-Jun Su, MA, Chief Doctor, Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan University, Donghu Road No. 169, Wuhan 430071, Hubei Province, China. 13697326659@139.com
Received: December 18, 2019
Peer-review started: December 18, 2019
First decision: February 20, 2020
Revised: March 17, 2020
Accepted: April 8, 2020
Article in press: April 8, 2020
Published online: June 26, 2020
Processing time: 190 Days and 3.4 Hours
Abstract
BACKGROUND

With continuous advancement of industrial society, environmental pollution has become more and more serious. There has been an increase in infertility caused by environmental factors. Nonylphenol (NP) is a stable degradation product widely used in daily life and production and has been proven to affect male fertility. However, the underlying mechanisms therein are unclear. Thus, it is necessary to study the effect and mechanism of NP on spermatogonial stem cells (SSCs).

AIM

To investigate the cytotoxic effect of NP on SSCs via the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway.

METHODS

SSCs were treated with NP at 0, 10, 20 or 30 µmol. MTT assay was performed to evaluate the effect of NP on the proliferation of SSCs. Flow cytometry was conducted to measure SSC apoptosis. The expression of Bad, Bcl-2, cytochrome-c, pro-Caspase 9, SOX-2, OCT-4, Nanog, Nanos3, Stra8, Scp3, GFRα1, CD90, VASA, Nanos2, KIT, PLZF and PI3K/AKT/mTOR-related proteins was observed by western blot, and the mRNA expression of SOX-2, OCT-4 and Nanog was detected by quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with untreated cells (0 μmol NP), SSCs treated with NP at all concentrations showed a decrease in cell proliferation and expression of Bcl-2, Nanog, OCT-4, SOX-2, Nanos3, Stra8, Scp3, GFRα1, CD90, VASA, Nanos2, KIT, and PLZF (P < 0.05), whereas the expression of Bad, cytochrome-c, and pro-Caspase 9 increased significantly (P < 0.05). We further examined the PI3K/AKT/mTOR pathway and found that the phosphorylation of PI3K, AKT, mTORC1, and S6K was significantly decreased by NP at all concentrations compared to that in untreated SSCs (P < 0.05). NP exerted the greatest effect at 30 μmol among all NP concentrations.

CONCLUSION

NP attenuated the proliferation, differentiation and stemness maintenance of SSCs while promoting apoptosis and oxidative stress. The associated mechanism may be related to the PI3K/AKT/mTOR pathway.

Keywords: Spermatogonial stem cells; Nonylphenol; Cytotoxicity; Phosphatidylinositol-3-kinase; Protein kinase B; Mammalian target of rapamycin

Core tip: With continuous advancement of industrial society, environmental pollution has become more and more serious. There has been an increase in infertility caused by environmental factors. Nonylphenol is a stable degradation product widely used in daily life and production and has been proven to affect male fertility. Our study demonstrated that nonylphenol reduced the proliferation, differentiation and stemness maintenance of spermatogonial stem cells while promoting apoptosis and oxidative stress. The mechanism may be related to the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway, providing a potential method for the treatment of male infertility.