RRC ID 54911
Author 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.
Title Dental pulp cell-derived powerful inducer of TNF-α comprises PKR containing stress granule rich microvesicles.
Journal Sci Rep
Abstract 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.
Volume 9(1)
Pages 3825
Published 2019-3-7
DOI 10.1038/s41598-019-40046-2
PII 10.1038/s41598-019-40046-2
PMID 30846715
PMC PMC6405945
MeSH Cell Line Cell-Derived Microparticles / metabolism* Cells, Cultured Dental Pulp / metabolism* Humans Inflammation / metabolism JNK Mitogen-Activated Protein Kinases / metabolism Macrophages / metabolism Monocytes / metabolism Signal Transduction Tumor Necrosis Factor-alpha / metabolism*
IF 4.011
Times Cited 2
Resource
Human and Animal Cells MCF7(RCB1904) THP-1(RCB1189)