Celastrol ameliorates Propionibacterium acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3

Phytomedicine. 2021 Jan:80:153398. doi: 10.1016/j.phymed.2020.153398. Epub 2020 Oct 24.

Abstract

Background: Celastrol, a pentacyclic triterpenoid quinonemethide isolated from several spp. of Celastraceae family, exhibits anti-inflammatory activities in a variety of diseases including arthritis.

Purpose: This study aims to investigate whether the inhibition of NLRP3 inflammasome is engaged in the anti-inflammatory activities of celastrol and delineate the underlying mechanism.

Methods: The influence of celastrol on NLRP3 inflammasome activation was firstly studied in lipopolysaccharide (LPS)-primed mouse bone marrow-derived macrophages (BMDMs) and phorbol 12-myristate 13-acetate (PMA)-primed THP-1 cells treated with nigericin. Reconstituted inflammasome was also established by co-transfecting NLRP3, ASC, pro-caspase-1 and pro-IL-1β in HEK293T cells. The changes of inflammasome components including NLRP3, ASC, pro-caspase-1/caspase-1 and pro-IL-1β/IL-1β were examined by enzyme-linked immunosorbent assay (ELISA), western blotting and immunofluorescence. Furthermore, Propionibacterium acnes (P. acnes)/LPS-induced liver injury and monosodium urate (MSU)-induced gouty arthritis in mice were employed in vivo to validate the inhibitory effect of celastrol on NLRP3 inflammasome.

Results: Celastrol significantly suppressed the cleavage of pro-caspase-1 and pro-IL-1β, while not affecting the protein expressions of NLRP3, ASC, pro-caspase-1 and pro-IL-1β in THP-1 cells, BMDMs and HEK293T cells. Celastrol suppressed NLRP3 inflammasome activation and alleviated P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis. Mechanism study revealed that celastrol could interdict K63 deubiquitination of NLRP3, which may concern interaction of celastrol and BRCA1/BRCA2-containing complex subunit 3 (BRCC3), and thereby prohibited the formation of NLRP3, ASC and pro-caspase-1 complex to block the generation of mature IL-1β.

Conclusion: Celastrol suppresses NLRP3 inflammasome activation in P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3, which presents a novel insight into inhibition of celastrol on NLRP3 inflammasome and provides more evidences for its application in the therapy of inflammation-related diseases.

Keywords: Celastrol; Deubiquitination; Gouty arthritis; IL-1β; Liver injury; NLRP3 inflammasome.

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Arthritis, Gouty / chemically induced
  • Arthritis, Gouty / drug therapy*
  • Arthritis, Gouty / metabolism
  • HEK293 Cells
  • Humans
  • Inflammasomes / drug effects
  • Inflammasomes / metabolism
  • Lipopolysaccharides / toxicity
  • Liver / drug effects*
  • Liver / microbiology
  • Liver / pathology
  • Lysine / metabolism
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • NLR Family, Pyrin Domain-Containing 3 Protein / genetics
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism*
  • Pentacyclic Triterpenes
  • Propionibacterium acnes / pathogenicity
  • THP-1 Cells
  • Triterpenes / pharmacology*
  • Ubiquitination / drug effects
  • Uric Acid / toxicity

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Inflammasomes
  • Lipopolysaccharides
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • NLRP3 protein, human
  • Nlrp3 protein, mouse
  • Pentacyclic Triterpenes
  • Triterpenes
  • Uric Acid
  • Lysine
  • celastrol