Format

Send to

Choose Destination
Immunology. 2010 Feb;129(2):178-85. doi: 10.1111/j.1365-2567.2009.03174.x. Epub 2009 Aug 17.

Expression and function of the NALP3 inflammasome in rheumatoid synovium.

Author information

1
Laboratoire de Rhumatologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.

Abstract

The NACHT, LRR and PYD domains containing protein (NALP3) inflammasome is a key regulator of interleukin-1 beta (IL-1 beta) secretion. As there is strong evidence for a pro-inflammatory role of IL-1 beta in rheumatoid arthritis (RA) and in murine models of arthritis, we explored the expression of the different components of the NALP3 inflammasome as well as other nucleotide oligomerization domain (NOD)-like receptors (NLRs) in synovium obtained from patients with RA. The expression of NLRs was also studied in fibroblast lines derived from joint tissue. By immunohistology, NALP3 and apoptosis-associated speck-like protein containing a CARD domain (ASC) were expressed in myeloid and endothelial cells and B cells. T cells expressed ASC but lacked NALP3. In synovial fibroblast lines, NALP3 expression was not detected at the RNA and protein levels and stimulation with known NALP3 agonists failed to induce IL-1 beta secretion. Interestingly, we were unable to distinguish RA from osteoarthritis synovial samples on the basis of their basal level of RNA expression of known NLR proteins, though RA samples contained higher levels of caspase-1 assayed by enzyme-linked immunosorbent assay. These results indicate that myeloid and endothelial cells are the principal sources of inflammasome-mediated IL-1 beta production in the synovium, and that synovial fibroblasts are unable to activate caspase-1 because they lack NALP3. The NALP3 inflammasome activity does not account for the difference in level of inflammation between RA and osteoarthritis.

PMID:
19824913
PMCID:
PMC2814460
DOI:
10.1111/j.1365-2567.2009.03174.x
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center