OATP2A1/SLCO2A1-mediated prostaglandin E2 loading into intracellular acidic compartments of macrophages contributes to exocytotic secretion
OATP2A1/SLCO2A1-mediated prostaglandin E2 loading into intracellular acidic compartments of macrophages contributes to exocytotic secretion
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DOI：
10.1016/j.bcp.2015.10.009
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发表时间：
2015-12-15
影响因子：
5.8
通讯作者：
Tamai, Ikumi
中科院分区：
文献类型：
--
作者：
Shimada, Hiroaki;Nakamura, Yoshinobu;Tamai, Ikumi
有显著的证据表明，诱导型环氧合酶亚型（考克斯-2）调节PGE（2）的细胞周浓度;然而，分泌过程的机制仍不清楚。因此，本研究旨在评价前列腺素转运蛋白（OATP 2A 1）在巨噬细胞分泌PGE（2）中的作用。Oatp 2a 1（Slco 2a 1）的免疫荧光染色主要在胞质结构域中检测到，并且在鼠巨噬细胞衍生的RAW 264细胞和腹膜巨噬细胞（PM）中与抗PGE（2）抗体、LysoTracker（R）和抗溶酶体相关膜蛋白（Lamp）I抗体部分共定位。OATP抑制剂和Slco 2a 1（+/-）PMs存在时，含有轻溶酶体的亚细胞组分对PGE（2）的摄取显著降低。在激活的巨噬细胞中，PGE（2）和溶酶体特异性N-乙酰-β-D-氨基葡萄糖苷酶的分泌增强，而在Ca 2+耗尽的条件下显著减少。从脂多糖激活的Slco 2a 1（-/-）PMs分泌的PGE（2）的量显著低于来自野生型（WT）小鼠的PMs。在来自Slco 2a 1（-/-）和WT小鼠的PM之间，考克斯-2和15-羟基前列腺素脱氢酶（15-Pgdh）的表达没有变化。这些结果表明，OATP 2A 1参与了PGE（2）向细胞内酸性区室（包括轻溶酶体）的加载。因此，OATP 2A 1通过Ca 2+内流诱导的胞吐作用促进巨噬细胞分泌PGE（2），与PGE（2）合成和代谢无关。(C)2015爱思唯尔公司All rights reserved.
There is significant evidence that the inducible cyclooxygenase isoform (COX-2) regulates the pericellular concentration of PGE(2); however, the mechanism of the secretory process remains unclear. The present study, therefore, aimed to evaluate the role of prostaglandin transporter (OATP2A1) in PGE(2) secretion from macrophages. lmmunofluorescence staining for Oatp2a1 (Slco2a1) was primarily detected in cytoplasmic domains, and was partially co-localized with anti-PGE(2) antibody, LysoTracker (R), and anti-lysosome-associated membrane protein (Lamp) I antibody in murine macrophage-derived RAW264 cells and peritoneal macrophages (PMs). PGE(2) uptake by subcellular fraction containing light lysosomes was reduced significantly in the presence of an OATP inhibitor and in Slco2a1(+/-) PMs. Secretion of PGE(2) and lysosome-specific N-acetyl-beta-D-glucosaminidase was enhanced in activated macrophagic cells, and diminished significantly under the Ca2+-depleted condition. The amount of PGE(2) secreted from lipopolysaccharide-activated Slco2a1(-/-) PMs was significantly lower than that from PMs from wild type (WT) mice. Expression of Cox-2 and 15-hydroxyprostaglandin dehydrogenase (15-Pgdh) was unchanged between PMs from Slco2a1(-/-) and WT mice. These results suggest that OATP2A1 is involved in PGE(2)-loading into intracellular acidic compartments, including light lysosomes. Thus, OATP2A1 contributes to PGE(2) secretion by macrophages via exocytosis induced by Ca2+ influx, independently of PGE(2) synthesis and metabolism. (C) 2015 Elsevier Inc. All rights reserved.