Double Stranded RNA-Dependent Protein Kinase is Necessary for TNF-α-Induced Osteoclast Formation In Vitro and In Vivo

Double-stranded RNA-dependent protein kinase (PKR) is involved in cell cycle progression, cell proliferation, cell differentiation, tumorgenesis, and apoptosis. We previously reported that PKR is required for differentiation and calcification in osteoblasts. TNF-α plays a key role in osteoclast differentiation. However, it is unknown about the roles of PKR in the TNF-α-induced osteoclast differentiation. The expression of PKR in osteoclast precursor RAW264.7 cells increased during TNF-α-induced osteoclastogenesis. The TNF-α-induced osteoclast differentiation in bone marrow-derived macrophages and RAW264.7 cells was markedly suppressed by the pre-treatment of PKR inhibitor, 2-aminopurine (2AP), as well as gene silencing of PKR. The expression of gene markers in the differentiated osteoclasts including TRAP, Calcitonin receptor, cathepsin K and ATP6V0d2 was also suppressed by the 2AP treatment. Bone resorption activity of TNF-α-induced osteoclasts was also supressed by 2AP treatment. Inhibition of PKR supressed the TNF-α-induced activation of NF-κB and MAPK in RAW264.7 cells. 2AP inhibited both the nuclear translocation of NF-κB and its transcriptional activity in RAW264.7 cells. 2AP inhibited the TNF-α-induced expression of NFATc1 and c-fos, master transcription factors in osteoclastogenesis. TNF-α-induced nuclear translocation of NFATc1 in mature osteoclasts was clearly inhibited by the 2AP treatment. The PKR inhibitor C16 decreased the TNF-α-induced osteoclast formation and bone resorption in mouse calvaria. The present study indicates that PKR is necessary for the TNF-α-induced osteoclast differentiation in vitro and in vivo.

内容要旨・審査要旨・論文本文の公開:
内容要旨 : LID201507171001.pdf
審査要旨 : LID201507171002.pdf
論文本文 : k2857_fulltext.pdf
本論文は，著者Hiroki Shinoharaの学位論文として提出され，学位審査・授与の対象となっている。
著者の申請により要約(2015-07-18公開)に替えて論文全文を公開(2019-09-26)

This is the peer reviewed version of the following article: Shinohara, H. , Teramachi, J. , Okamura, H. , Yang, D. , Nagata, T. and Haneji, T. (2015), Double Stranded RNA‐Dependent Protein Kinase is Necessary for TNF‐α‐Induced Osteoclast Formation In Vitro and In Vivo. J. Cell. Biochem., 116: 1957-1967, which has been published in final form at https://doi:10.1002/jcb.25151. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.