Interleukin 34 (IL-34) cell-surface localization regulated by the molecular chaperone 78-kDa glucose-regulated protein facilitates the differentiation of monocytic cells
Interleukin 34 (IL-34) cell-surface localization regulated by the molecular chaperone 78-kDa glucose-regulated protein facilitates the differentiation of monocytic cells
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DOI：
10.1074/jbc.ra118.006226
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发表时间：
2019-02-15
影响因子：
4.8
通讯作者：
Magari, Masaki
中科院分区：
文献类型：
--
作者：
Ogawa, Sayaka;Matsuoka, Yukiko;Magari, Masaki
白细胞介素 34 (IL-34) 是一种细胞因子，与 CSF-1 具有共同的受体，即集落刺激因子 1 受体 (CSF-1R)。我们最近发现了一种新型单核细胞，称为滤泡树突状细胞诱导的单核细胞 (FDMC)，其分化依赖于通过滤泡树突状细胞系 FL-Y 产生的 IL-34 进行的 CSF-1R 信号传导。在这里，我们报告了 FDMC 分化背后的 IL-34 介导的 CSF-1R 信号传导的功能机制。 CRIPSR/Cas9介导的Il34基因敲除证实FL-Y细胞诱导FDMC的能力完全取决于FL-Y细胞表达的IL-34。 Transwell 培养实验表明，在 FDMC 前体细胞和 FL-Y 细胞之间的直接相互作用中，FDMC 分化需要来自 FL-Y 细胞表面膜锚定形式的 IL-34 的信号，而不是来自分泌形式的信号。此外，使用抗IL-34抗体的流式细胞术分析表明IL-34也在FL-Y细胞表面上表达。因此，我们探索了 FL-Y 细胞中与 IL-34 相互作用的蛋白质。质谱分析和 Pulldown 测定确定 IL-34 与 FL-Y 细胞质膜部分中的分子伴侣 78-kDa 葡萄糖调节蛋白 (GRP78) 相关。与这一发现一致，与原始FL-Y细胞相比，GRP78杂合子FL-Y细胞在其细胞表面表达较低水平的IL-34蛋白，并且表现出诱导FDMC分化的能力降低。这些结果表明 IL-34 在 FL-Y 细胞中与单核细胞分化相关的新型 GRP78 依赖性定位和特定功能。
Interleukin 34 (IL-34) constitutes a cytokine that shares a common receptor, colony-stimulating factor-1 receptor (CSF-1R), with CSF-1. We recently identified a novel type of monocytic cell termed follicular dendritic cell-induced monocytic cells (FDMCs), whose differentiation depended on CSF-1R signaling through the IL-34 produced from a follicular dendritic cell line, FL-Y. Here, we report the functional mechanisms of the IL-34-mediated CSF-1R signaling underlying FDMC differentiation. CRIPSR/Cas9-mediated knockout of the Il34 gene confirmed that the ability of FL-Y cells to induce FDMCs completely depends on the IL-34 expressed by FL-Y cells. Transwell culture experiments revealed that FDMC differentiation requires a signal from a membrane-anchored form of IL-34 on the FL-Y cell surface, but not from a secreted form, in a direct interaction between FDMC precursor cells and FL-Y cells. Furthermore, flow cytometric analysis using an anti-IL-34 antibody indicated that IL-34 was also expressed on the FL-Y cell surface. Thus, we explored proteins interacting with IL-34 in FL-Y cells. Mass spectrometry analysis and pulldown assay identified that IL-34 was associated with the molecular chaperone 78-kDa glucose-regulated protein (GRP78) in the plasma membrane fraction of FL-Y cells. Consistent with this finding, GRP78-heterozygous FL-Y cells expressed a lower level of IL-34 protein on their cell surface and exhibited a reduced competency to induce FDMC differentiation compared with the original FL-Y cells. These results indicated a novel GRP78-dependent localization and specific function of IL-34 in FL-Y cells related to monocytic cell differentiation.