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Lysine392, a K63-linked ubiquitination site in NEMO, mediates inflammatory osteoclastogenesis and osteolysis

Muhammad Alhawagri1, Yasuhiro Yamanaka, Dean Ballard

  • 1Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, USA.

Journal of Orthopaedic Research : Official Publication of the Orthopaedic Research Society
|September 14, 2011
PubMed

Insights

Polymethyl methacrylate (PMMA) particles from bone implants cause osteolysis. Targeting the NEMO Lysine 392 residue in the IKK complex can impair this process by affecting NF-κB and Erk activation.

Area of Science:

  • Biomedical Engineering
  • Immunology
  • Orthopedics

Background:

  • Polymethyl methacrylate (PMMA) particles from bone implants are a major cause of osteolysis and implant failure.
  • The precise mechanisms of PMMA-induced osteolysis, particularly the inflammatory pathways, remain unclear.
  • Nuclear factor kappa-B (NF-κB) and MAP kinase pathways are known to be central to inflammatory osteolysis.

Purpose of the Study:

  • To identify key molecular mediators in PMMA particle-induced osteolysis.
  • To investigate the role of the NEMO protein, specifically Lysine 392, in osteoclastogenesis and osteolysis.
  • To explore potential therapeutic targets for combating PMMA-induced osteolysis.

Main Methods:

  • Utilized genetically modified mice with a NEMO-K392R mutation.
  • Assessed the impact of this mutation on PMMA particle-induced osteoclast formation and osteolytic responses.
  • Analyzed the activation of NF-κB and various MAP kinases (including Erk) in response to PMMA particles.

Main Results:

  • Mice with the NEMO-K392R mutation exhibited impaired PMMA-induced osteoclastogenesis and osteolysis.
  • This impairment was associated with reduced activation of NF-κB and Erk signaling pathways.
  • Other MAP kinase pathways did not appear to be significantly affected.

Conclusions:

  • Lysine 392 of NEMO is a critical mediator in PMMA particle-induced inflammatory osteoclastogenesis and osteolysis.
  • The NEMO Lysine 392 residue plays a significant role in activating NF-κB and Erk signaling, crucial for osteolysis.
  • Targeting the NEMO Lysine 392 motif presents a promising strategy for preventing or treating PMMA-induced osteolysis.

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