Author:
Wu Yifan,Jin Yang,Sun Tianyu,Zhu Piaoyu,Li Jinlong,Zhang Qinglin,Wang Xiaoke,Jiang Junkang,Chen Gang,Zhao Xinyuan
Abstract
Abstract
Background
Most nanoparticles (NPs) reportedly block autophagic flux, thereby upregulating p62/SQSTM1 through degradation inhibition. p62 also acts as a multifunctional scaffold protein with multiple domains, and is involved in various cellular processes. However, the autophagy substrate-independent role of p62 and its regulation at the transcriptional level upon NPs exposure remain unclear.
Results
In this work, we exposed BEAS-2b cells and mice to silica nanoparticles (SiNPs), and found that SiNPs increased p62 protein levels in vivo and vitro. Then, we further explored the role and mechanism of SiNPs-stimulated p62 in vitro, and found that p62 degradation was inhibited due to autophagic flux blockade. Mechanistically, SiNPs blocked autophagic flux through impairment of lysosomal capacity rather than defective autophagosome fusion with lysosomes. Moreover, SiNPs stimulated translocation of NF-E2-related factor 2 (Nrf2) to the nucleus from the cytoplasm, which upregulated p62 transcriptional activation through direct binding of Nrf2 to the p62 promoter. Nrf2 siRNA dramatically reduced both the mRNA and protein levels of p62. These two mechanisms led to p62 protein accumulation, thus increasing interleukin (IL)-1 and IL-6 expression. SiNPs activated nuclear factor kappa B (NF-κB), and this effect could be alleviated by p62 knockdown.
Conclusion
SiNPs caused accumulation of p62 through both pre- and post-translational mechanisms, resulting in airway inflammation. These findings improve our understanding of SiNP-induced pulmonary damage and the molecular targets available to mitigate it.
Funder
Large Instruments Open Foundation of Nantong University
National Natural Science Foundation of China
Nantong Jiangsu scientific research project
Postgraduate Research & Practice Innovation Program of Jiangsu Province
Scientific Research Project of Wuxi Health and Family Planning Commission
The Yong Medical Talents of wuxi
Qinglan Project of Jiangsu Province of China
Publisher
Springer Science and Business Media LLC
Subject
Pharmaceutical Science,Applied Microbiology and Biotechnology,Biomedical Engineering,Molecular Medicine,Medicine (miscellaneous),Bioengineering
Cited by
22 articles.
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