Dental pulp cell-derived powerful inducer of TNF-α comprises PKR containing stress granule rich microvesicles.
Dental pulp cell-derived powerful inducer of TNF-α comprises PKR containing stress granule rich microvesicles.
复制标题
牙髓细胞衍生的 TNF-α 强效诱导剂包含含有富含应激颗粒的微泡的 PKR。
DOI：
10.1038/s41598-019-40046-2
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发表时间：
2019
影响因子：
4.6
通讯作者：
Nishimura F.
中科院分区：
文献类型：
--
作者：
Suzuki S;Fukuda T;Nagayasu S;Nakanishi J;Yoshida K;Hirata-Tsuchiya S;Nakao Y;Sano T;Yamashita A;Yamada S;Ohta K;Shiba H;Nishimura F.
众所周知，牙髓组织可以引起在人体中观察到的一些最严重的急性炎症。我们发现牙髓细胞分泌一种诱导巨噬细胞产生肿瘤坏死因子-α的因子，并将该因子命名为牙髓细胞源性TNF-α强效诱导因子（DPIT）。DPIT在牙髓细胞中被诱导并通过微泡转运到受体细胞。用PKR抑制剂处理牙髓细胞显著抑制DPIT活性，并且细胞内组成性激活弱干扰素信号。在受体巨噬细胞中，用含DPIT的牙髓细胞上清液刺激导致核因子-κB和MAP激酶如JNK和p38的激活。蛋白质组学分析显示，许多应激颗粒相关蛋白存在于牙髓细胞的上清液中，以及微泡标记蛋白如GAPDH、β-肌动蛋白、HSPA 8、HSPB 1、HSPE 1和HSPD 1。此外，在牙髓细胞来源的微泡中检测到大分子AHNAK和PKR，并且牙髓细胞中AHNAK的基因沉默导致DPIT活性降低。因此，DPIT的核心蛋白是PKR，并且PKR在具有AHNAK的应激颗粒聚集体中保持活性状态，并通过微囊泡转运。DPIT诱导TNF-α的活性远上级革兰氏阴性细菌内毒素。因此，我们首次报道，活性PKR通过微泡作为应激颗粒聚集体转运，并在巨噬细胞中诱导强大的炎症信号。
It is well known that dental pulp tissue can evoke some of the most severe acute inflammation observed in the human body. We found that dental pulp cells secrete a factor that induces tumor necrosis factor-α production from macrophages, and designated this factor, dental pulp cell-derived powerful inducer of TNF-α (DPIT). DPIT was induced in dental pulp cells and transported to recipient cells via microvesicles. Treatment of dental pulp cells with a PKR inhibitor markedly suppressed DPIT activity, and weak interferon signals were constitutively activated inside the cells. In recipient macrophages, stimulation with DPIT-containing supernatants from pulp cells resulted in activation of both nuclear factor-κB and MAP kinases like JNK and p38. Proteomics analyses revealed that many stress granule-related proteins were present in supernatants from dental pulp cells as well as microvesicle marker proteins like GAPDH, β-actin, HSPA8, HSPB1, HSPE1, and HSPD1. Furthermore, giant molecule AHNAK and PKR were detected in microvesicles derived from dental pulp cells, and gene silencing of AHNAK in dental pulp cells led to reduced DPIT activity. Thus, it appeared that the core protein of DPIT was PKR, and that PKR was maintained in an active state in stress granule aggregates with AHNAK and transported via microvesicles. The activity of DPIT for TNF-α induction was far superior to that of gram-negative bacterial endotoxin. Therefore, we, report for the first time, that active PKR is transported via microvesicles as stress granule aggregates and induces powerful inflammatory signals in macrophages.