TREK‑TRAAK two‑pore domain potassium channels protect human retinal pigment epithelium cells from oxidative stress

Huang,Hao; Li,Han; Shi,Kangpei; Wang,Lei; Zhang,Xiaotong; Zhu,Xiaobo

doi:10.3892/ijmm.2018.3813

TREK‑TRAAK two‑pore domain potassium channels protect human retinal pigment epithelium cells from oxidative stress

Authors:
- Hao Huang
- Han Li
- Kangpei Shi
- Lei Wang
- Xiaotong Zhang
- Xiaobo Zhu
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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: August 8, 2018 https://doi.org/10.3892/ijmm.2018.3813
Pages: 2584-2594
Copyright: © Huang et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

The aim of the current study was to explore the potential of TREK‑TRAAK two‑pore domain potassium (K2P) channels in protecting human retinal pigment epithelium (hRPE) cells against oxidative stress. hRPE cells were obtained from donors, and then cell identification and detection of the expression levels of TREK‑TRAAK K2P channels in hRPE cells were conducted. Subsequently, tert‑butyl hydroperoxide (t‑BH) was used to induce oxidative stress in hRPE cells. Docosahexaenoic acid (DHA) was used to stimulate and fluoxetine was used to inhibit the TREK‑TRAAK K2P channels. The survival rates of hRPE cells under oxidative stress were examined using flow cytometry. Apoptosis‑associated factors, including Bax, Bcl‑2, cleaved‑caspase‑3, αB‑crystallin and their mRNAs, were examined using immunofluorescence, western blot and reverse transcription‑polymerase chain reaction analyses. Variations in the cytoarchitecture were observed by immunofluorescence and electron microscopy. The cells examined in the present study were identified as hRPE cells. All members in the TREK‑TRAAK K2P channel family (including TREK‑1, TREK‑2 and TRAAK) were found to be expressed in hRPE cells. Stimulation of TREK‑TRAAK K2P channels increased the survival rates of hRPE cells under oxidative stress and the levels of intracellular protective factors, such as Bcl‑2 and αB‑crystallin. By contrast, inhibition of these channels decreased the cell survival rates and increased apoptosis enhancing factors, such as Bax and cleaved‑caspase‑3. Further examination of the cytoarchitecture revealed that TREK‑TRAAK K2P channels protected the integrity of the hRPE cell structure against oxidative stress. In conclusion, the present study suggested that the activated TREK‑TRAAK K2P channels serve a role in protecting hRPE cells against the oxidative stress induced by t‑BH, which indicated that these K2P channels are potential novel targets in retinal protection and provided a new direction for research and therapy in retinal degeneration diseases.

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1	Pascolini D and Mariotti SP: Global estimates of visual impairment: 2010. Br J Ophthalmol. 96:614–618. 2012. View Article : Google Scholar
2	Athanasiou D, Aguilà M, Bevilacqua D, Novoselov SS, Parfitt DA and Cheetham ME: The cell stress machinery and retinal degeneration. FEBS Lett. 587:2008–2017. 2013. View Article : Google Scholar : PubMed/NCBI
3	Zhu XB, Luo Y, Xie L, Gao Y, Ding XY, Ma HJ, Chen HY and Tang SB: Inhibition of photoreceptor apoptosis in RCS rats by caspase-9 inhibitor. Chin J Pathophysiol. 23:7–11. 2007.In Chinese.
4	Perche O, Doly M and Ranchon-Cole I: Transient protective effect of caspase inhibitors in RCS rat. Exp Eye Res. 86:519–527. 2008. View Article : Google Scholar : PubMed/NCBI
5	Talley EM, Solorzano G, Lei Q, Kim D and Bayliss DA: Cns distribution of members of the two-pore-domain (KCNK) potassium channel family. J Neurosci. 21:7491–7505. 2001. View Article : Google Scholar : PubMed/NCBI
6	Honore E: The neuronal background K2P channels: Focus on TREK1. Nat Rev Neurosci. 8:251–261. 2007. View Article : Google Scholar : PubMed/NCBI
7	Noël J, Sandoz G and Lesage F: Molecular regulations governing TREK and TRAAK channel functions. Channels (Austin). 5:402–409. 2011. View Article : Google Scholar
8	Buckler KJ: Two-pore domain K+ channels and their role in chemoreception. Adv Exp Med Biol. 661:15–30. 2010. View Article : Google Scholar
9	Laigle C, Confort-Gouny S, Le Fur Y, Cozzone PJ and Viola A: Deletion of TRAAK potassium channel affects brain metabolism and protects against ischemia. PLoS One. 7:e532662012. View Article : Google Scholar
10	Bayliss DA and Barrett PQ: Emerging roles for two-pore-domain potassium channels and their potential therapeutic impact. Trends Pharmacol Sci. 29:566–575. 2008. View Article : Google Scholar : PubMed/NCBI
11	Heurteaux C, Laigle C, Blondeau N, Jarretou G and Lazdunski M: Alpha-linolenic acid and riluzole treatment confer cerebral protection and improve survival after focal brain ischemia. Neuroscience. 137:241–251. 2006. View Article : Google Scholar
12	Judge SI and Smith PJ: Patents related to therapeutic activation of K(ATP) and K(2P) potassium channels for neuroprotection: Ischemic/hypoxic/anoxic injury and general anesthetics. Expert Opin Ther Pat. 19:433–460. 2009. View Article : Google Scholar : PubMed/NCBI
13	Enyedi P and Czirjak G: Molecular background of leak K⁺ currents: Two-pore domain potassium channels. Physiol Rev. 90:559–605. 2010. View Article : Google Scholar : PubMed/NCBI
14	Querques G, Forte R and Souied EH: Retina and omega-3. J Nutr Metab. 2011:7483612011. View Article : Google Scholar : PubMed/NCBI
15	Kennard LE, Chumbley JR, Ranatunga KM, Armstrong SJ, Veale EL and Mathie A: Inhibition of the human two-pore domain potassium channel, TREK-1, by fluoxetine and its metabolite norfluoxetine. Br J Pharmacol. 144:821–829. 2005. View Article : Google Scholar : PubMed/NCBI
16	Dong YY, Pike AC, Mackenzie A, McClenaghan C, Aryal P, Dong L, Quigley A, Grieben M, Goubin S, Mukhopadhyay S, et al: K2P channel gating mechanisms revealed by structures of TREK-2 and a complex with Prozac. Science. 347:1256–1259. 2015. View Article : Google Scholar : PubMed/NCBI
17	Lee AK, Smart JL, Rubinstein M, Low MJ and Tse A: Reciprocal regulation of TREK-1 channels by arachidonic acid and CRH in mouse corticotropes. Endocrinology. 152:1901–1910. 2011. View Article : Google Scholar : PubMed/NCBI
18	Shen C, Li C, Zhu X, Zheng W and Xia R: Effect of TRAAK activator riluzole on t-BHP induced injury of human retinal pigment epithelial cells. Chin J Ocul Fund Dis. 29:400–405. 2013.In Chinese.
19	Shen CL, Ma W, Zheng W, Huang H, Xia R, Li C and Zhu X: The antioxidant effects of riluzole on the APRE-19 cell model injury-induced by t-BHP. BMC Ophthalmol. 17:2102017. View Article : Google Scholar
20	Lin SF, Mao YX, Zheng JL, Hu J and Tang SB: An improved primary culture and freezing and recovery method of human retina pigment epithelium. J Pract Med Tech. 19:791–793. 2012.In Chinese.
21	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
22	Plafker SM, O'Mealey GB and Szweda LI: Mechanisms for countering oxidative stress and damage in retinal pigment epithelium. Int Rev Cell Mol Biol. 298:135–177. 2012. View Article : Google Scholar : PubMed/NCBI
23	Wei MC, Zong WX, Cheng EH, Lindsten T, Panoutsakopoulou V, Ross AJ, Roth KA, MacGregor GR, Thompson CB and Korsmeyer SJ: Proapoptotic BAX and BAK: A requisite gateway to mitochondrial dysfunction and death. Science. 292:727–730. 2001. View Article : Google Scholar : PubMed/NCBI
24	Shi Y: Mechanisms of caspase activation and inhibition during apoptosis. Mol Cell. 9:459–470. 2002. View Article : Google Scholar : PubMed/NCBI
25	Sheekumar PG, Chothe P, Sharma KK, Baid R, Kompella U, Spee C, Kannan N, Manh C, Ryan SJ, Ganapathy V, et al: Antiapoptotic properties of alpha-crystallin-derived peptide chaperones and characterization of their uptake transporters in human RPE cells. Invest Ophthalmol Vis Sci. 54:2787–2798. 2013. View Article : Google Scholar
26	Ousman SS, Tomooka BH, van Noort JM, Wawrousek EF, O'Connor KC, Hafler DA, Sobel RA, Robinson WH and Steinman L: Protective and therapeutic role for alphaB-crystallin in autoimmune demyelination. Nature. 448:474–479. 2007. View Article : Google Scholar : PubMed/NCBI
27	Corrochano S, Barhoum R, Boya P, Arroba AI, Rodríguez-Muela N, Gómez-Vicente V, Bosch F, de Pablo F, de la Villa P and de la Rosa EJ: Attenuation of vision loss and delay in apoptosis of photoreceptors induced by proinsulin in a mouse model of retinitis pigmentosa. Invest Ophthalmol Vis Sci. 49:4188–4194. 2008. View Article : Google Scholar : PubMed/NCBI
28	Heisenberg CP and Bellaïche Y: Forces in tissue morphogenesis and patterning. Cell. 153:948–962. 2013. View Article : Google Scholar : PubMed/NCBI
29	Blanchoin L, Boujemaa-Paterski R, Sykes C and Plastino J: Actin dynamics, architecture, and mechanics in cell motility. Physiol Rev. 94:235–263. 2014. View Article : Google Scholar : PubMed/NCBI
30	Dan Dunn J, Alvarez LA, Zhang X and Soldati T: Reactive oxygen species and mitochondria: A nexus of cellular homeostasis. Redox Biol. 6:472–485. 2015. View Article : Google Scholar : PubMed/NCBI