Interleukin 34 (IL-34) cell-surface localization regulated by the molecular chaperone 78-kDa glucose-regulated protein facilitates the differentiation of monocytic cells

• Published in: The Journal of biological chemistry Vol. 294; no. 7; pp. 2386 - 2396
• Main Authors: Ogawa, Sayaka, Matsuoka, Yukiko, Takada, Miho, Matsui, Kazue, Yamane, Fumihiro, Kubota, Eri, Yasuhara, Shiori, Hieda, Kentaro, Kanayama, Naoki, Hatano, Naoya, Tokumitsu, Hiroshi, Magari, Masaki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.02.2019; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; cell differentiation; Cell Differentiation - physiology; Cell Line; Cell Membrane - genetics; Cell Membrane - metabolism; cell surface protein; chaperone; colony-stimulating factor-1 receptor; CRISPR/Cas; cytokine; Dendritic Cells, Follicular - cytology; Dendritic Cells, Follicular - metabolism; follicular dendritic cell; Gene Expression Regulation - physiology; GRP78; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Immunology; interleukin; interleukin 34; Interleukins - biosynthesis; Interleukins - genetics; Male; Mice; Mice, Inbred BALB C; monocyte; Monocytes - cytology; Monocytes - metabolism; plasma membrane; Western blot; cytokine; Western blot; interleukin 34; cell differentiation; cell surface protein; plasma membrane; GRP78; colony-stimulating factor-1 receptor; follicular dendritic cell; chaperone; monocyte; interleukin; CRISPR/Cas
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA118.006226

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.