@article{1eacb91e3de642ae82e05d4d405d04ae,
title = "Attenuation of periostin in retinal m{\"u}ller glia by TNF-α and IFN-γ",
abstract = "● AIM: To investigate the regulation and mechanisms of periostin expression in retinal M{\"u}ller glia, and to explore the relevance to retinal neovascularization. ● METHODS: The oxygen-induced retinopathy (OIR) mouse model and the human Moorfield/Institute of Ophthalmology-M{\"u}ller 1 (MIO-M1) cell line were used in the study. Immunofluorescence staining was used to determine the distribution and expression of periostin and a M{\"u}ller glial cell marker glutamine synthetase (GS). Cytokines TNF-α and IFN-γ were added to stimulate the MIO-M1 cells. ShRNA was used to knockdown periostin expression in MIO-M1 cells. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was conducted to assess the mRNA expression of periostin. ● RESULTS: Immunofluorescence staining showed that periostin was expressed by MIO-M1 M{\"u}ller glia. GS-positive M{\"u}ller glia and periostin increased in OIR retinas, and were partially overlaid. The stimulation of TNF-α and IFN-γ reduced the mRNA expression of periostin significantly and dose-dependently in MIO-M1 cells. Knockdown of periostin reduced mRNA expression of vascular endothelial growth factor A (VEGFA) in MIO-M1 cells, while VEGFA expression was not changed in periostin knock-out OIR retinas. ● CONCLUSION: M{\"u}ller glia could be one of the main sources of periostin in the retina, and might contribute to the pathogenesis of retinal neovascularization. Proinflammatory cytokines TNF-α and IFN-γ attenuate the periostin expression in retinal M{\"u}ller glia, which provides a potential and novel method in treating retinal neovascular diseases.",
author = "Peng, {Ying Qian} and Cao, {Man Jing} and Shigeo Yoshida and Zhang, {Lu Si} and Zeng, {Hui Lan} and Zou, {Jing Ling} and Yoshiyuki Kobayashi and Takahito Nakama and Shi, {Jing Ming} and Jia, {Song Bai} and Zhou, {Ye Di}",
note = "Funding Information: with M{\"u}ller glia marker GS, and MIO-M1 M{\"u}ller glial cells expressed periostin in vitro (Figure 1). Thus, M{\"u}ller glia might be one major source for periostin. TNF-α and IFN-γ attenuated periostin mRNA expression in MIO-M1 cells (Figure 2). These results indicated that proinflammatory cytokines TNF-α and IFN-γ might be important in the regulation of periostin produced by M{\"u}ller glia. The mechanism why these two cytokines could reduce periostin in vitro still remained unclear. Previous studies showed that M2-polarized macrophages produced periostin[11], and periostin could be induced by Th2 cytokines such as IL-4 and IL-13[16]. Periostin should have strong relevance to Th2 response with an anti-inflammatory effect. Moreover, both periostin and anti-inflammatory M2 macrophages enhanced ocular neovascularization[7,13,35-36]. Thus, pro-inflammation might possess an inhibitory effect on periostin production. The relationship between periostin and VEGF still remains controversial. Liu et al[37]reported that periostin enhanced tumor angiogenesis through activation of Erk/VEGF signaling in pancreatic cancer, and VEGF in the cancer tissues was significantly correlated with the expression of periostin. Periostin was also considered to have a significant positive correlation with VEGF in osteosarcoma patients[38] and in patients with esophageal squamous cell carcinoma[39], inducing and/or promoting tumor angiogenesis. Periostin also promoted VEGF secretion in keloid fibroblasts[40]. Another study showed that periostin shRNA-infection reduced VEGFA expression in GSC. Moreover, periostin and VEGFA were strongly associated with the progression of GSC[26]. However, the concentration of periostin in vitreous was not significantly correlated with those of VEGF in the vitreous of PDR patients[12]. In the present study, the in vitro and in vivo studies showed controversial results. IFN-γ and TNF-α down-regulate the VEGFA mRNA level in MIO-M1 cell line after 8h stimulation, while the VEGFA mRNA level has not been affected at 24h after the stimulation of TNF-α (Figure 3). Moreover, although the knockdown of periostin attenuated mRNA expression of VEGFA in MIO-M1 cell line, the deficiency of periostin does not affect the expression of VEGFA in the whole retina of OIR (Figures 4 and 5). A possible reason of this phenomenon might be that under hypoxia, VEGF can be expressed by many kinds of source cells besides M{\"u}ller glia, such as macrophages[41], retinal pigment epithelial (RPE) cells[42], etc. The attenuation of VEGFA in glial cells could be masked by the increase from those cells. Further studies are needed to determine whether experimental inhibition of periostin can attenuate retinal fibrovascular membrane formation ex-vivo and in vivo. Moreover, the mechanisms by which TNF-α and IFN-γ can induce down-regulation of periostin in mice is worth investigation. Periostin might be a novel target for PDR and it might have a synergistic effect with anti-VEGF treatment, and targeting these molecules by state-of-the-art strategies such as gene-editing using CRSPR-Cas9 system could be considered for the future investigations and clinical applications[43]. ACKNOWLEDGEMENTS Foundations: Supported by National Natural Science Foundation of China (No.81800855; No.81800856; No.81700837); Natural Science Foundation of Hunan Province (No.2018JJ3765); Department of Science and Technology, Hunan (No.2015TP2007); Japan Society for the Promotion of Science KAKENHI Grants (No.26293374; No.16K15734). Conflicts of Interest: Peng YQ, None; Cao MJ, None; Yoshida S, None; Zhang LS, None; Zeng HL, None; Zou JL, None; Kobayashi Y, None; Nakama T, None; Shi JM, None; Jia SB, None; Zhou YD, None. Funding Information: Supported by National Natural Science Foundation of China (No.81800855; No.81800856; No.81700837); Natural Science Foundation of Hunan Province (No.2018JJ3765); Department of Science and Technology, Hunan (No.2015TP2007); Japan Society for the Promotion of Science KAKENHI Grants (No.26293374; No.16K15734). Publisher Copyright: {\textcopyright} 2019, International Journal of Ophthalmology (c/o Editorial Office). All rights reserved.",
year = "2019",
month = feb,
doi = "10.18240/ijo.2019.02.05",
language = "English",
volume = "12",
pages = "212--218",
journal = "International Journal of Ophthalmology",
issn = "2222-3959",
publisher = "Press of International Journal of Ophthalmology",
number = "2",
}
