Licorice isoliquiritigenin-encapsulated mesoporous silica nanoparticles for osteoclast inhibition and bone loss prevention

Theranostics. 2019 Jul 9;9(18):5183-5199. doi: 10.7150/thno.33376. eCollection 2019.

Abstract

Mesoporous silica nanoparticles (MSNs) are extensively used in bone tissue regeneration and local drug delivery. However, the effects of MSNs alone on osteoclast formation and function, as well as the utilization of MSNs to deliver natural molecules against bone resorption, remain unexplored. Here, we report the development of licorice-derived bioactive flavonoid isoliquiritigenin (ISL)-encapsulated MSNs (MSNs-ISL) as a potent bone-bioresponsive nanoencapsulation system for prevention of osteoclast-mediated bone loss in vitro and in vivo. Methods: We synthesized MSNs-ISL and then investigated the drug loading and release characteristics of the resulting nanoparticles. In vitro experiments on osteoclast differentiation and bone resorption were performed using mouse primary bone marrow-derived macrophages (BMMs). In vivo animal experiments were conducted using a lipopolysaccharide (LPS)-mediated calvarial bone erosion model. Results: The resulting MSNs-ISL were spherical and highly monodispersed; they possessed a large specific surface area and superior biocompatibility, and allowed acid-sensitive sustained drug release. Compared with free ISL and MSNs alone, MSNs-ISL significantly and additively inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast generation, decreased the size and quantity of sealing zones, and reduced the osteolytic capacity of osteoclasts in vitro. MSNs-ISL treatment also downregulated RANKL-stimulated mRNA expression of osteoclast-associated genes and transcription factors. Mechanistically, MSNs-ISL remarkably attenuated the RANKL-initiated expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of mitogen-activated protein kinases (MAPKs), and phosphorylation and degradation of inhibitor of κBα (IκBα), together with the nuclear translocation of nuclear factor-κB (NF-κB) p65 and the activator protein (AP)-1 component c-Fos. Moreover, MSNs-ISL almost completely restrained the expression of nuclear factor of activated T cells (NFATc1). Consistent with the in vitro results, MSNs-ISL could block osteoclast activity; relieve inflammation-related calvarial bone destruction in vivo; and suppress c-Fos, NFATc1, and cathepsin K expression levels. Conclusion: Licorice ISL-encapsulated MSNs exhibit notable anti-osteoclastogenetic effects and protect against inflammatory bone destruction. Our findings reveal the feasibility of applying MSNs-ISL as an effective natural product-based bone-bioresponsive nanoencapsulation system to prevent osteoclast-mediated bone loss.

Keywords: drug delivery; isoliquiritigenin; lipopolysaccharide; mesoporous silica nanoparticles; osteoclast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Bone Resorption / drug therapy*
  • Bone Resorption / pathology
  • Bone Resorption / prevention & control*
  • Chalcones / chemical synthesis
  • Chalcones / pharmacology
  • Chalcones / therapeutic use*
  • Gene Expression Regulation / drug effects
  • Glycyrrhiza / chemistry*
  • Lipopolysaccharides
  • MAP Kinase Signaling System / drug effects
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Male
  • Mice, Inbred C57BL
  • NF-kappa B / metabolism
  • Nanoparticles / chemistry*
  • Nanoparticles / ultrastructure
  • Osteoclasts / drug effects
  • Osteoclasts / metabolism
  • Osteoclasts / pathology*
  • Osteogenesis / drug effects
  • Osteogenesis / genetics
  • Porosity
  • RANK Ligand / pharmacology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction / drug effects
  • Silicon Dioxide / chemistry*
  • Skull / pathology

Substances

  • Actins
  • Chalcones
  • Lipopolysaccharides
  • NF-kappa B
  • RANK Ligand
  • RNA, Messenger
  • Silicon Dioxide
  • isoliquiritigenin