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Discovery may aid autoimmune
treatment
ANN ARBOR, Mich., -- University of Michigan
scientists say
a new discovery could help scientists
understand what causes
autoimmune diseases like rheumatoid
arthritis. In a study
published online in Nature,
researchers from the university's
medical school found
that the protein cryopyrin responds to
invading bacteria
by triggering the activation of a powerful
inflammatory
molecule called IL-1beta, which signals the
immune system
to attack pathogens and induces fever to pro-
tect the
body against infection. Found in the fluid inside
cells,
cryopyrin is a member of the NOD-LRR family of pro-
teins,
which protect cells against microbial infection.
Defective
cryopyrin is associated with increased suscept-
ibility to
infection. Small mutations in CIAS1 --the human
gene for
cryopyrin-- are known to cause three rare auto-
inflammatory diseases: familial cold autoinflammatory syn-
drome, Muckle-Wells syndrome and neonatal-onset multiple-
system inflammatory disease. The scientists found that
activated cryopyrin triggers a enzyme called caspase-1,
which splits the immature form of IL-1beta to produce the
active form of the molecule. Once IL-1beta is activated,
it can be secreted out of the cell where it binds to the
IL-1beta receptor on other cells to trigger an immune
response.
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