Autophagy regulates TGF-β2-induced epithelial-mesenchymal transition in human retinal pigment epithelium cells

Wu,Jing; Chen,Xiaoyun; Liu,Xialin; Huang,Shan; He,Chang; Chen,Baoxin; Liu,Yizhi

doi:10.3892/mmr.2017.8360

Autophagy regulates TGF-β2-induced epithelial-mesenchymal transition in human retinal pigment epithelium cells

Authors:
- Jing Wu
- Xiaoyun Chen
- Xialin Liu
- Shan Huang
- Chang He
- Baoxin Chen
- Yizhi Liu
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Affiliations: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
Published online on: December 27, 2017 https://doi.org/10.3892/mmr.2017.8360
Pages: 3607-3614
Copyright: © Wu et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Transforming growth factor (TGF)-β2-induced epithelial-mesenchymal transition (EMT) in human retinal pigment epithelium (RPE) cells has an important role in the pathophysiology of intraocular fibrotic disorders, which may cause vision impairment and blindness. Autophagy, an intracellular homeostatic pathway, contributes to the physiological and pathological processes of RPE. Furthermore, autophagy has previously been reported to function in the EMT process in numerous tissue and cell types. However, the association between autophagy and the EMT process in RPE cells has not yet been fully determined. The present study demonstrated that TGF‑β2‑treated human RPE cells (ARPE‑19 cell line) exhibited a significantly increased autophagic flux compared with control cells, as determined by western blot analysis of the protein levels of microtubule‑associated protein 1 light chain 3‑II and p62 (also termed sequestosome 1). Furthermore, it was demonstrated that autophagy activation enhanced the TGF‑β2‑induced EMT process in ARPE‑19 cells, and inhibition of autophagy by chloroquine administration attenuated TGF‑β2‑induced EMT, which was determined by analyzing the expression of mesenchymal and epithelial markers by reverse transcription‑quantitative polymerase chain reaction and/or western blotting. A transwell migration and invasion assays was also performed that demonstrated that autophagy activation by rapamycin enhanced TGF‑β2‑stimulated RPE cell migration and invasion, and inhibition of autophagy reduced TGF‑β2‑stimulated RPE cell migration and invasion. These results also demonstrated that autophagy activation enhanced the TGF‑β2‑induced EMT process in ARPE‑19 cells, and inhibition of autophagy attenuated TGF‑β2‑induced EMT. Overall, the results of the present study demonstrated that TGF‑β2‑induced EMT may be regulated by autophagy, thus indicating that autophagy may serve as a potential therapeutic target for the attenuation of EMT in intraocular fibrotic disorders.

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1	Strauss O: The retinal pigment epithelium in visual function. Physiol Rev. 85:845–881. 2005. View Article : Google Scholar : PubMed/NCBI
2	Priglinger CS, Obermann J, Szober CM, Merl-Pham J, Ohmayer U, Behler J, Gruhn F, Kreutzer TC, Wertheimer C, Geerlof A, et al: Epithelial-to-mesenchymal transition of rpe cells in vitro confers increased beta1,6-N-glycosylation and increased susceptibility to galectin-3 binding. PLoS One. 11:e01468872016. View Article : Google Scholar : PubMed/NCBI
3	Kampik A, Green WR, Quigley HA and Pierce LH: Scanning and transmission electron microscopic studies of two cases of pigment dispersion syndrome. Am J Ophthalmol. 91:573–587. 1981. View Article : Google Scholar : PubMed/NCBI
4	Machemer R: Proliferative vitreoretinopathy (PVR): A personal account of its pathogenesis and treatment. Proctor lecture Invest Ophthalmol Vis Sci. 29:1771–1783. 1988.PubMed/NCBI
5	Hiscott P, Sheridan C, Magee RM and Grierson I: Matrix and the retinal pigment epithelium in proliferative retinal disease. Prog Retin Eye Res. 18:167–190. 1999. View Article : Google Scholar : PubMed/NCBI
6	Chen X, Ye S, Xiao W, Luo L and Liu Y: Differentially expressed microRNAs in TGFβ2-induced epithelial-mesenchymal transition in retinal pigment epithelium cells. Int J Mol Med. 33:1195–1200. 2014. View Article : Google Scholar : PubMed/NCBI
7	Hirasawa M, Noda K, Noda S, Suzuki M, Ozawa Y, Shinoda K, Inoue M, Ogawa Y, Tsubota K and Ishida S: Transcriptional factors associated with epithelial-mesenchymal transition in choroidal neovascularization. Mol Vis. 17:1222–1230. 2011.PubMed/NCBI
8	Zou M, Zhu W, Wang L, Shi L, Gao R, Ou Y, Chen X, Wang Z, Jiang A, Liu K, et al: AEG-1/MTDH-activated autophagy enhances human malignant glioma susceptibility to TGF-β1-triggered epithelial-mesenchymal transition. Oncotarget. 7:13122–13138. 2016. View Article : Google Scholar : PubMed/NCBI
9	Ghavami S, Cunnington RH, Gupta S, Yeganeh B, Filomeno KL, Freed DH, Chen S, Klonisch T, Halayko AJ, Ambrose E, et al: Autophagy is a regulator of TGF-β1-induced fibrogenesis in primary human atrial myofibroblasts. Cell Death Dis. 6:e16962015. View Article : Google Scholar : PubMed/NCBI
10	Ni BB, Li B, Yang YH, Chen JW, Chen K, Jiang SD and Jiang LS: The effect of transforming growth factor β1 on the crosstalk between autophagy and apoptosis in the annulus fibrosus cells under serum deprivation. Cytokine. 70:87–96. 2014. View Article : Google Scholar : PubMed/NCBI
11	Kim SI, Na HJ, Ding Y, Wang Z, Lee SJ and Choi ME: Autophagy promotes intracellular degradation of type I collagen induced by transforming growth factor (TGF)-β1. J Biol Chem. 287:11677–11688. 2012. View Article : Google Scholar : PubMed/NCBI
12	Grassi G, Di Caprio G, Santangelo L, Fimia GM, Cozzolino AM, Komatsu M, Ippolito G, Tripodi M and Alonzi T: Autophagy regulates hepatocyte identity and epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions promoting Snail degradation. Cell Death Dis. 6:e18802015. View Article : Google Scholar : PubMed/NCBI
13	Bertrand M, Petit V, Jain A, Amsellem R, Johansen T, Larue L, Codogno P and Beau I: SQSTM1/p62 regulates the expression of junctional proteins through epithelial-mesenchymal transition factors. Cell Cycle. 14:364–374. 2015. View Article : Google Scholar : PubMed/NCBI
14	Li J, Yang B, Zhou Q, Wu Y, Shang D, Guo Y, Song Z, Zheng Q and Xiong J: Autophagy promotes hepatocellular carcinoma cell invasion through activation of epithelial-mesenchymal transition. Carcinogenesis. 34:1343–1351. 2013. View Article : Google Scholar : PubMed/NCBI
15	Klionsky DJ and Emr SD: Autophagy as a regulated pathway of cellular degradation. Science. 290:1717–1721. 2000. View Article : Google Scholar : PubMed/NCBI
16	Sinha D, Valapala M, Shang P, Hose S, Grebe R, Lutty GA, Zigler JS Jr, Kaarniranta K and Handa JT: Lysosomes: Regulators of autophagy in the retinal pigmented epithelium. Exp Eye Res. 144:46–53. 2016. View Article : Google Scholar : PubMed/NCBI
17	Hyttinen JM, Petrovski G, Salminen A and Kaarniranta K: 5′-Adenosine monophosphate-activated protein kinase-mammalian target of rapamycin axis as therapeutic target for age-related macular degeneration. Rejuvenation Res. 14:651–660. 2011. View Article : Google Scholar : PubMed/NCBI
18	Mitter SK, Song C, Qi X, Mao H, Rao H, Akin D, Lewin A, Grant M, Dunn W Jr, Ding J, et al: Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD. Autophagy. 10:1989–2005. 2014. View Article : Google Scholar : PubMed/NCBI
19	Johansson I, Monsen VT, Pettersen K, Mildenberger J, Misund K, Kaarniranta K, Schønberg S and Bjørkøy G: The marine n-3 PUFA DHA evokes cytoprotection against oxidative stress and protein misfolding by inducing autophagy and NFE2L2 in human retinal pigment epithelial cells. Autophagy. 11:1636–1651. 2015. View Article : Google Scholar : PubMed/NCBI
20	Chen X, Xiao W, Wang W, Luo L, Ye S and Liu Y: The complex interplay between ERK1/2, TGFβ/Smad and Jagged/Notch signaling pathways in the regulation of epithelial-mesenchymal transition in retinal pigment epithelium cells. PLoS One. 9:e963652014. View Article : Google Scholar : PubMed/NCBI
21	Asaria RH, Kon CH, Bunce C, Sethi CS, Limb GA, Khaw PT, Aylward GW and Charteris DG: Silicone oil concentrates fibrogenic growth factors in the retro-oil fluid. Br J Ophthalmol. 88:1439–1442. 2004. View Article : Google Scholar : PubMed/NCBI
22	Baudouin C, Fredj-Reygrobellet D, Brignole F, Negre F, Lapalus P and Gastaud P: Growth factors in vitreous and subretinal fluid cells from patients with proliferative vitreoretinopathy. Ophthalmic Res. 25:52–59. 1993. View Article : Google Scholar : PubMed/NCBI
23	Livak KJ and Schmittgen TD: Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) method. Methods. 25:402–408. 2001. View Article : Google Scholar : PubMed/NCBI
24	Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, Adachi H, Adams CM, Adams PD, Adeli K, et al: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition). Autophagy. 12:1–222. 2016. View Article : Google Scholar : PubMed/NCBI
25	Lee SY, Oh JS, Rho JH, Jeong NY, Kwon YH, Jeong WJ, Ryu WY, Ahn HB, Park WC, Rho SH, et al: Retinal pigment epithelial cells undergoing mitotic catastrophe are vulnerable to autophagy inhibition. Cell Death Dis. 5:e13032014. View Article : Google Scholar : PubMed/NCBI
26	Liu YD, Wang ZB, Han G and Zhao P: Hyperbaric oxygen treatment attenuates neuropathic pain by elevating autophagy flux via inhibiting mTOR pathway. Am J Transl Res. 9:2629–2638. 2017.PubMed/NCBI
27	Zhou Q, Zhang H, Wu Q, Shi J and Zhou S: Pharmacological manipulations of autophagy modulate paraquat-induced cytotoxicity in PC12 cells. Int J Biochem Mol Biol. 8:13–22. 2017.PubMed/NCBI
28	Cui D, Sun D, Wang X, Yi L, Kulikowicz E, Reyes M, Zhu J, Yang ZJ, Jiang W and Koehler RC: Impaired autophagosome clearance contributes to neuronal death in a piglet model of neonatal hypoxic-ischemic encephalopathy. Cell Death Dis. 8:e29192017. View Article : Google Scholar : PubMed/NCBI
29	Alimpeti S and Andreadis ST: CDH2 and CDH11 act as regulators of stem cell fate decisions. Stem Cell Res. 14:270–282. 2015. View Article : Google Scholar : PubMed/NCBI
30	Pankov R and Yamada KM: Fibronectin at a glance. J Cell Sci. 115:3861–3863. 2002. View Article : Google Scholar : PubMed/NCBI
31	Eriksson JE, Dechat T, Grin B, Helfand B, Mendez M, Pallari HM and Goldman RD: Introducing intermediate filaments: From discovery to disease. J Clin Invest. 119:1763–1771. 2009. View Article : Google Scholar : PubMed/NCBI
32	Thiery JP and Sleeman JP: Complex networks orchestrate epithelial-mesenchymal transitions. Nat Rev Mol Cell Biol. 7:131–142. 2006. View Article : Google Scholar : PubMed/NCBI