Leclaire Martin Dominik, Nettels-Hackert Gerburg, König Jeannette, Höhn Annika, Grune Tilman, Uhlig Constantin E, Hansen Uwe, Eter Nicole, Heiduschka Peter
Research Laboratory, Department of Ophthalmology, University Medical Center, Domagkstr. 15, D-48149, Münster, Germany.
German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany.
Graefes Arch Clin Exp Ophthalmol. 2019 May;257(5):931-952. doi: 10.1007/s00417-019-04253-x. Epub 2019 Jan 28.
To examine the reaction of microglial cells (MG) when incubated with lipofuscin (LP) in vitro with emphasis on the immunological reaction of the MG toward LP and the suppression of this reaction by immunomodulatory agents. MG are involved in the pathogenesis of degenerative eye disorders such as age-related macular degeneration (AMD). LP is a heterogeneous waste material that accumulates in the retinal pigment epithelium (RPE) cells with advancing age. LP is known to have toxic effects on RPE cells and therefore an elevated LP-derived fundus autofluorescence is a risk factor for AMD development. MG in the subretinal space have been reported in eyes affected by AMD. Moreover, in senescent mice, subretinal MG were found, which display an autofluorescence that may be derived from LP uptake.
In this study, we incubated MG (BV-2 cell line and primary cells from murine brain) in vitro with LP isolated from the human RPE. We observed phagocytosis, studied cell morphologies, and analyzed the cell culture supernatants. We also investigated the effect of the immunomodulatory agents hydrocortisone (HC), minocycline, and the tripeptide TKP.
The MG phagocytosed the LP quickly and completely. We detected highly elevated levels of pro-inflammatory cytokines (especially of IL-6, IL-23p19, TNF-α, KC, RANTES, and IL-1α) in the cell culture supernatants. Furthermore, levels of vascular endothelial growth factor (VEGF) were raised in BV-2 cells. Anti-inflammatory agents added to the cell cultures inhibited the inflammatory reaction, in particular hydrocortisone (HC). Minocycline and TKP had less impact on the cytokine release.
The interaction of MG and LP could play a role in the development of retinal degeneration by triggering an inflammatory reaction and angiogenesis.
研究小胶质细胞（MG）在体外与脂褐质（LP）孵育时的反应，重点关注MG对LP的免疫反应以及免疫调节因子对该反应的抑制作用。MG参与包括年龄相关性黄斑变性（AMD）在内的退行性眼病的发病机制。LP是一种异质性废物，随着年龄增长在视网膜色素上皮（RPE）细胞中积累。已知LP对RPE细胞有毒性作用，因此LP衍生的眼底自发荧光升高是AMD发生的危险因素。在受AMD影响的眼睛的视网膜下间隙中已报道存在MG。此外，在衰老小鼠中发现了视网膜下MG，其显示出可能源自LP摄取的自发荧光。
在本研究中，我们将MG（BV-2细胞系和来自鼠脑的原代细胞）在体外与人RPE分离的LP一起孵育。我们观察了吞噬作用，研究了细胞形态，并分析了细胞培养上清液。我们还研究了免疫调节因子氢化可的松（HC）、米诺环素和三肽TKP的作用。
MG迅速且完全地吞噬了LP。我们在细胞培养上清液中检测到促炎细胞因子（尤其是IL-6、IL-23p19、TNF-α、KC、RANTES和IL-1α）水平高度升高。此外，BV-2细胞中血管内皮生长因子（VEGF）水平升高。添加到细胞培养物中的抗炎剂抑制了炎症反应，尤其是氢化可的松（HC）。米诺环素和TKP对细胞因子释放的影响较小。
MG与LP的相互作用可能通过引发炎症反应和血管生成在视网膜变性的发展中起作用。
