Soluble RANKL cleaved from activated lymphocytes by TNF-α-converting enzyme contributes to osteoclastogenesis in periodontitis

Hiroyuki Kanzaki, Seicho Makihira, Maiko Suzuki, Takenobu Ishii, Alexandru Movila, Josefine Hirschfeld, Hani Mawardi, Xiaoping Lin, Xiaozhe Han, Martin A. Taubman, Toshihisa Kawai

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Host immune responses play a key role in promoting bone resorption in periodontitis via receptor activator of NF-κB ligand (RANKL)-dependent osteoclastogenesis. Both membrane-bound RANKL (mRANKL) expressed on lymphocytes and soluble RANKL (sRANKL) are found in periodontal lesions. However, the underlying mechanism and cellular source of sRANKL release and its biological role in periodontitis are unclear. TNF-α-converting enzyme (TACE) is reported to cleave the following: 1) precursor TNF-α with release of mature, soluble TNF-α and 2) mRANKL with release of sRANKL. Both soluble TNF-α and sRANKL are found in the periodontitis lesion, leading to the hypothesis that TACE expressed on lymphocytes is engaged in RANKL shedding and that the resulting sRANKL induces osteoclastogenesis. In the current study, upon stimulating PBLs with mitogens in vitro, RANKL expression, sRANKL secretion, and TACE expression were all upregulated. Among the four putative mRANKL sheddases examined in neutralization assays, TACE was the only functional sheddase able to cleave mRANKL expressed on PBL. Moreover, PBL culture supernatant stimulated with mitogens in the presence of anti-TACE Ab or anti-RANKL Ab showed a marked reduction of osteoclastogenesis from osteoclast precursors, indicating that TACE-mediated sRANKL may possess sufficient osteoclastogenic activity. According to double-color confocal microscopy, B cells expressed a more pronounced level of RANKL and TACE expression than T cells or monocytes in periodontally diseased gingiva. Conditioned medium of patients' gingival lymphocyte culture increased in vitro osteoclastogenic activity, which was suppressed by the addition of anti-TACE Ab and anti-RANKL Ab. Therefore, TACE-mediated cleavage of sRANKL from activated lymphocytes, especially B cells, can promote osteoclastogenesis in periodontitis.

Original languageEnglish
Pages (from-to)3871-3883
Number of pages13
JournalJournal of Immunology
Volume197
Issue number10
DOIs
Publication statusPublished - Nov 15 2016

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All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology

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