Reveromycin A, an agent for osteoporosis, inhibits bone resorption by inducing apoptosis specifically in osteoclasts

Je Tae Woo*, Makoto Kawatani, Masanori Kato, Toshimasa Shinki, Takayuki Yonezawa, Naoki Kanoh, Hiroshi Nakagawa, Masamichi Takami, Kun Hyung Lee, Paula H. Stern, Kazuo Nagai, Hiroyuki Osada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Mature bone-resorbing osteoclasts (OCs) mediate excessive bone loss seen in several bone disorders, including osteoporosis. Here, we showed that reveromycin A (RM-A), a small natural product with three carboxylic groups in its structure, induced apoptosis specifically in OCs, but not in OC progenitors, nonfunctional osteoclasts, or osteoblasts. RM-A inhibited protein synthesis in OCs by selectively blocking enzymatic activity of isoleucyl-tRNA synthetase. The proapoptotic effect of RM-A was inhibited by neutralization or disruption of the acidic microenvironment, a prominent characteristic of OCs. RM-A was incorporated in OCs but not in nonfunctional osteoclasts and OC progenitors in neutral culture medium. Effects of RM-A on OC apoptosis increased under acidic culture conditions. RM-A not only was incorporated, but also induced apoptosis in OC progenitors in acidic culture medium. RM-A inhibited osteoclastic pit formation, decreased prelabeled 45Ca release in organ cultures, and antagonized increased bone resorption in ovariectomized mice. These results suggested that preventive effects of RM-A on bone resorption in vitro and in vivo were caused by apoptosis through inhibition of isoleucyl-tRNA synthetase in OCs and that specific sensitivity of OCs to RM-A was due to the acidic microenvironment, which increased cell permeability of RM-A by suppressing dissociation of protons from carboxylic acid moieties, making them less polar. This unique mechanism suggested that RM-A might represent a type of therapeutic agent for treating bone disorders associated with increased bone loss.

Original languageEnglish (US)
Pages (from-to)4729-4734
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number12
DOIs
StatePublished - Mar 21 2006

Keywords

  • Antiresorptive agent
  • Inhibitor
  • Isoleucyl-tRNA synthetase

ASJC Scopus subject areas

  • General

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