title: Role of the leucine-rich repeat domain of cryopyrin/NALP3 in monosodium urate crystal-induced inflammation in mice.
abstract: OBJECTIVE
  The mechanism by which monosodium urate monohydrate (MSU) crystals intracellularly activate the cryopyrin inflammasome is unknown. The aim of this study was to use a mouse molecular genetics-based approach to test whether the leucine-rich repeat (LRR) domain of cryopyrin is required for MSU crystal-induced inflammation.
  
  
  METHODS
  Cryopyrin-knockout lacZ (Cryo(-Z/-Z)) mice and mice with the cryopyrin LRR domain deleted and fused to the lacZ reporter (Cryo(DeltaLRR Z/DeltaLRR Z)) were generated using bacterial artificial chromosome-based targeting vectors, which allow for large genomic deletions. Bone marrow-derived macrophages from Cryo(DeltaLRR Z/DeltaLRR Z) mice, Cryo(-Z/-Z) mice, and congenic wild-type (WT) mice were challenged with endotoxin-free MSU crystals under serum-free conditions. Phagocytosis and cytokine expression were assessed by flow cytometry and enzyme-linked immunosorbent assay. MSU crystals also were injected into mouse synovial-like subcutaneous air pouches. The in vivo inflammatory responses were examined.
  
  
  RESULTS
  Release of interleukin-1beta (IL-1beta), but not CXCL1 and tumor necrosis factor alpha, was impaired in Cryo(DeltaLRR Z/DeltaLRR Z) and Cryo(-Z/-Z) mouse bone marrow-derived macrophages compared with WT mouse bone marrow-derived macrophages in response to not only MSU crystals but also other known stimuli that activate the cryopyrin inflammasome. In addition, a comparable percentage of MSU crystals taken up by each type of bone marrow-derived macrophage was observed. Moreover, total leukocyte infiltration in the air pouch and IL-1beta production were attenuated in Cryo(-Z/-Z) and Cryo(DeltaLRR Z/DeltaLRR Z) mice at 6 hours postinjection of MSU crystals compared with WT mice.
  
  
  CONCLUSIONS
  MSU crystal-induced inflammatory responses were comparably attenuated both in vitro and in vivo in Cryo(DeltaLRR Z/DeltaLRR Z) and Cryo(-Z/-Z) mice. Hence, the LRR domain of cryopyrin plays a role in mediating MSU crystal-induced inflammation in this model.
authors.affiliation: University of California, San Diego, USA.
authors.forename: Hal M
authors.initials: HM
authors.lastname: Hoffman
authors.forename: Peter
authors.initials: P
authors.lastname: Scott
authors.forename: James L
authors.initials: JL
authors.lastname: Mueller
authors.forename: Amir
authors.initials: A
authors.lastname: Misaghi
authors.forename: Sean
authors.initials: S
authors.lastname: Stevens
authors.forename: George D
authors.initials: GD
authors.lastname: Yancopoulos
authors.forename: Andrew
authors.initials: A
authors.lastname: Murphy
authors.forename: David M
authors.initials: DM
authors.lastname: Valenzuela
authors.forename: Ru
authors.initials: R
authors.lastname: Liu-Bryan
mesh_terms: D000818:Animals; D015210:Arthritis, Gouty / Q000276:immunology / Q000378:metabolism*; D001854:Bone Marrow Cells; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005260:Female; D000090263:Leucine-Rich Repeat Proteins; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D010587:Phagocytosis / Q000187:drug effects; D011506:Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid; D012867:Skin / Q000187:drug effects / Q000473:pathology; D014527:Uric Acid / Q000276:immunology / Q000633:toxicity
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D000090263:Leucine-Rich Repeat Proteins; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D011506:Proteins; D014527:Uric Acid