Suppression of monosodium urate crystal-induced inflammation by inhibiting TGF-β-activated kinase 1-dependent signaling: role of the ubiquitin proteasome system. Academic Article uri icon

Overview

abstract

  • Monosodium urate (MSU) crystals activate inflammatory pathways that overlap with interleukin-1β (IL-1β) signaling. However, the post-translational mechanisms involved and the role of signaling proteins in this activation are unknown. In the present study, we investigated the intracellular signaling mechanisms involved in MSU-induced activation of THP-1 macrophages and human nondiseased synovial fibroblasts (NLSFs) and the in vivo efficacy of an inhibitor of tumor growth factor-β (TGF-β)-activated kinase 1 (TAK1), 5Z-7-oxozeaenol, in MSU-induced paw inflammation in C57BL/6 mice. THP-1 macrophage activation with MSU crystals (25-200 µg/ml) resulted in the rapid and sustained phosphorylation of interleukin-1 receptor-activated kinase 1 (IRAK1 Thr209) and TAK1 (Thr184/187) and their association with the E3 ubiquitin ligase TRAF6. At the cellular level, MSU inhibited the deubiquitinases A20 and UCHL2 and increased 20s proteasomal activity, leading to a global decrease in K63-linked ubiquitination and increase in K48-linked ubiquitination in THP-1 macrophages. While MSU did not stimulate cytokine production in NLSFs, it significantly amplified IL-1β-induced IL-6, IL-8, and ENA-78/CXCL5 production. Docking studies and MD simulations followed by TAK1 in vitro kinase assays revealed that uric acid molecules are capable of arresting TAK1 in an active-state conformation, resulting in sustained TAK1 kinase activation. Importantly, MSU-induced proinflammatory cytokine production was completely inhibited by 5Z-7-oxozeaenol but not IRAK1/4 or TRAF6 inhibitors. Administration of 5Z-7-oxozeaenol (5 or 15 mg/kg; orally) significantly inhibited MSU-induced paw inflammation in C57BL/6 mice. Our study identifies a novel post-translational mechanism of TAK1 activation by MSU and suggests the therapeutic potential of TAK1 in regulating MSU-induced inflammation.

publication date

  • September 11, 2019

Research

keywords

  • Gout
  • Inflammation
  • Lactones
  • MAP Kinase Kinase Kinases
  • Proteasome Endopeptidase Complex
  • Resorcinols
  • Ubiquitin
  • Uric Acid

Identity

PubMed Central ID

  • PMC7853128

Scopus Document Identifier

  • 85074001271

Digital Object Identifier (DOI)

  • 10.1038/s41423-019-0284-3

PubMed ID

  • 31511642

Additional Document Info

volume

  • 18

issue

  • 1