Degradation of Photoreceptor Outer Segments by the Retinal Pigment Epithelium Requires Pigment Epithelium-Derived Factor Receptor (PEDF-R).
Degradation of Photoreceptor Outer Segments by the Retinal Pigment Epithelium Requires Pigment Epithelium-Derived Factor Receptor (PEDF-R).
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DOI：
10.1167/iovs.62.2.30
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发表时间：
2021-02-01
影响因子：
4.4
通讯作者：
Becerra SP
中科院分区：
文献类型：
--
作者：
Bullock J;Polato F;Abu-Asab M;Bernardo-Colón A;Aflaki E;Agbaga MP;Becerra SP
探讨色素上皮衍生因子受体（PEDF-R）在吞噬过程中的作用。以前，我们确定PEDF-R，PNPLA 2基因编码的蛋白质，作为磷脂酶A2在视网膜色素上皮细胞（RPE）。在吞噬过程中，RPE细胞以感光器外节（POS）尖端的形式摄取丰富的磷脂和蛋白质，然后将其水解。PEDF-R在RPE吞噬作用中的作用尚不清楚。产生RPE中PNPLA 2被条件性敲除（cKO）的小鼠。培养小鼠RPE/脉络膜外植体。用siPNPLA 2沉默双链体转染人ARPE-19细胞。从牛视网膜中分离POS。使用磷脂酶A2抑制剂溴烯醇内酯。进行透射电子显微镜、免疫荧光、脂质标记、脉冲追踪实验、蛋白质印迹以及游离脂肪酸和β-羟基丁酸酯测定。与同窝对照组相比，cKO小鼠的RPE积累了脂质，以及更丰富、更大的视紫红质颗粒。在POS暴露后，与对照相比，来自cKO小鼠的RPE外植体释放较少的β-羟基丁酸酯。在吞噬过程中的POS摄入后，视紫红质降解停滞在溴烯醇内酯处理的细胞和PNPLA 2敲低的细胞相对于其相应的控制。磷脂酶A2抑制降低吞噬RPE细胞的β-羟基丁酸酯释放。PNPLA 2敲除还导致吞噬RPE细胞释放的脂肪酸和β-羟基丁酸酯减少。PEDF-R下调延迟吞噬过程中的POS消化。这些发现意味着RPE吞噬作用的效率取决于PEDF-R，从而确定了这种蛋白质对RPE中POS降解的新贡献。
To examine the contribution of pigment epithelium-derived factor receptor (PEDF-R) to the phagocytosis process. Previously, we identified PEDF-R, the protein encoded by the PNPLA2 gene, as a phospholipase A2 in the retinal pigment epithelium (RPE). During phagocytosis, RPE cells ingest abundant phospholipids and protein in the form of photoreceptor outer segment (POS) tips, which are then hydrolyzed. The role of PEDF-R in RPE phagocytosis is not known. Mice in which PNPLA2 was conditionally knocked out (cKO) in the RPE were generated. Mouse RPE/choroid explants were cultured. Human ARPE-19 cells were transfected with siPNPLA2 silencing duplexes. POSs were isolated from bovine retinas. The phospholipase A2 inhibitor bromoenol lactone was used. Transmission electron microscopy, immunofluorescence, lipid labeling, pulse–chase experiments, western blots, and free fatty acid and β-hydroxybutyrate assays were performed. The RPE of the cKO mice accumulated lipids, as well as more abundant and larger rhodopsin particles, compared to littermate controls. Upon POS exposure, RPE explants from cKO mice released less β-hydroxybutyrate compared to controls. After POS ingestion during phagocytosis, rhodopsin degradation was stalled both in cells treated with bromoenol lactone and in PNPLA2-knocked-down cells relative to their corresponding controls. Phospholipase A2 inhibition lowered β-hydroxybutyrate release from phagocytic RPE cells. PNPLA2 knockdown also resulted in a decline in fatty acids and β-hydroxybutyrate release from phagocytic RPE cells. PEDF-R downregulation delayed POS digestion during phagocytosis. The findings imply that the efficiency of RPE phagocytosis depends on PEDF-R, thus identifying a novel contribution of this protein to POS degradation in the RPE.
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影响因子：
3.4
作者：
Mazzoni, Francesca;Safa, Hussein;Finnemann, Silvia C.
通讯作者：
Finnemann, Silvia C.
DOI：
10.1074/jbc.m110.107854
发表时间：
2010-06-25
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Chandak PG;Radovic B;Aflaki E;Kolb D;Buchebner M;Fröhlich E;Magnes C;Sinner F;Haemmerle G;Zechner R;Tabas I;Levak-Frank S;Kratky D
通讯作者：
Kratky D
影响因子：
56.9
作者：
Haemmerle, G;Lass, A;Zechner, R
通讯作者：
Zechner, R
影响因子：
3.5
作者：
D'Cruz, PM;Yasumura, D;Vollrath, D
通讯作者：
Vollrath, D
DOI：
10.1152/physiol.00038.2009
发表时间：
2010-02
期刊：
Physiology (Bethesda, Md.)
影响因子：
--
作者：
Kevany BM;Palczewski K
通讯作者：
Palczewski K