A novel pyrazole derivative protects from ovariectomy-induced osteoporosis through the inhibition of NADPH oxidase

Sci Rep. 2016 Mar 15;6:22389. doi: 10.1038/srep22389.


Osteoclast cells (OCs) are differentiated from bone marrow-derived macrophages (BMMs) by activation of receptor activator of nuclear factor κB (NF-κB) ligand (RANKL). Activation of NADPH oxidase (Nox) isozymes is involved in RANKL-dependent OC differentiation, implicating Nox isozymes as therapeutic targets for treatment of osteoporosis. Here, we show that a novel pyrazole derivative, Ewha-18278 has high inhibitory potency on Nox isozymes. Blocking the activity of Nox with Ewha-18278 inhibited the responses of BMMs to RANKL, including reactive oxygen species (ROS) generation, activation of mitogen-activated protein (MAP) kinases and NF-κB, and OC differentiation. To evaluate the anti-osteoporotic function of Ewha-18278, the derivative was applied to estrogen-deficient ovariectomized (OVX) ddY mice. Oral administration of Ewha-18278 (10 mg/kg/daily, 4 weeks) into the mice recovered bone mineral density, trabecular bone volume, trabecular bone length, number and thickness, compared to control OVX ddY mice. Moreover, treatment of OVX ddY mice with Ewha-18278 increased bone strength by increasing cortical bone thickness. We provide that Ewha-18278 displayed Nox inhibition and blocked the RANKL-dependent cell signaling cascade leading to reduced differentiation of OCs. Our results implicate Ewha-18278 as a novel therapeutic agent for the treatment of osteoporosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Area Under Curve
  • Blotting, Western
  • Bone Density / drug effects
  • Cell Differentiation / drug effects
  • Cells, Cultured
  • Female
  • Membrane Glycoproteins / antagonists & inhibitors*
  • Membrane Glycoproteins / metabolism
  • Metabolic Clearance Rate
  • Mice
  • Mice, Inbred C57BL
  • Mitogen-Activated Protein Kinases / metabolism
  • Molecular Structure
  • NADPH Oxidase 2
  • NADPH Oxidases / antagonists & inhibitors*
  • NADPH Oxidases / metabolism
  • NF-kappa B / metabolism
  • Osteoclasts / cytology
  • Osteoclasts / drug effects
  • Osteoporosis / etiology
  • Osteoporosis / metabolism
  • Osteoporosis / prevention & control*
  • Ovariectomy / adverse effects*
  • Protective Agents / administration & dosage
  • Protective Agents / chemistry
  • Protective Agents / pharmacology
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacokinetics
  • Pyrazoles / pharmacology*
  • RANK Ligand / metabolism
  • Signal Transduction / drug effects


  • Ewha-18278
  • Membrane Glycoproteins
  • NF-kappa B
  • Protective Agents
  • Pyrazoles
  • RANK Ligand
  • Cybb protein, mouse
  • NADPH Oxidase 2
  • NADPH Oxidases
  • Mitogen-Activated Protein Kinases