title: Silibinin negatively contributes to primary cilia length via autophagy regulated by histone deacetylase 6 in confluent mouse embryo fibroblast 3T3-L1 cells.
abstract: Primary cilium is a cellular antenna, signalling as a sensory organelle. Numerous pathological manifestation is associated with change of its length. Although the interaction between autophagy and primary cilia has been suggested, the role of autophagy in primary cilia length is largely unknown. In this study the primary cilia were immunostained and observed by using confocal fluorescence microscopy, and we found that silibinin, a natural flavonoid, shortened the length of primary cilia, meanwhile it also induced autophagy in 3T3-L1 cells. This study was designed to investigate the significance of silibinin-induced autophagy in primary ciliary structure in confluent mouse embryo fibroblast 3T3-L1 cells. Either blocking the autophagic flux with pre-treatment with the autophagy inhibitor, 3-methyladenine (3-MA), or transfection of siRNA targeting LC3 inhibited the reduction of cilia length caused by silibinin exposure. Autophagy induced by silibinin decreased expressions of the cilia-associated proteins, such as IFT88, KIF3a and Ac-tubulin, while 3-MA restored it, indicating that autophagy induced by silibinin led to a reduction of primary cilia length. Histone deacetylase 6 (HDAC6), which was suggested as a mediator of autophagy, was up-regulated by silibinin in a time-dependent manner. In addition, 3T3-L1 cells treated with siRNA against HDAC6 had a reduced autophagic level and were protected from silibinin-induced cilia shortening. Taken together, we conclude that the HDAC6-mediated autophagy negatively regulates primary cilia length during silibinin treatment and has the potential to serve as a therapeutic target for primary cilia-associated ciliopathies. These findings thus provide new information about the potential link between autophagy and primary cilia.
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xu
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Liu
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Liu
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Hongju
authors.initials: H
authors.lastname: Wang
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Yao
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Linghe
authors.initials: L
authors.lastname: Zang
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Medical Education and Primary Care, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Tashiro
authors.affiliation: Department of Clinical and Pharmaceutical Sciences, Showa Pharmaceutical University, Tokyo, 194-8543, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Onodera
authors.affiliation: China-Japan Research Institute of Medical and Pharmaceutical Sciences, Pharmaceutical University, Shenyang, 110016, China. ikejimat@vip.sina.com.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ikejima
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D002923:Cilia / Q000378:metabolism; D004622:Embryo, Mammalian / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000378:metabolism*; D051379:Mice; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology*
chemical_list: D012838:Silymarin; D000077385:Silybin; C499033:Hdac6 protein, mouse; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases
keywords: 3T3-L1 cells; Autophagy; HDAC6; Primary cilia; Silibinin