Essential role for proteinase-activated receptor-2 in arthritis
J. Clin. Invest. William R. Ferrell, et al. 111:35 doi:10.1172/JCI16913 [
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Figure 4Chronic joint inflammation is inhibited by
PAR-2 gene disruption and PAR-2 is upregulated in inflamed tissues. (
a) Comparison of the response to induction of adjuvant arthritis in
PAR-2+/+ mice (filled triangles),
PAR-2–/– mice (open circles), and heterozygous mice (filled squares). An acute (24–hour) phase is followed by a progressive increase in joint diameter that reached a plateau by about 14 days in all but the
PAR-2–/– group, which did not develop a chronic response. Data are presented as mean ± SEM;
n = 6–8. (
b) X-gal staining of normal synovial tissue in a
PAR-2–/– mouse shows a rich density of staining for β-galactosidase activity limited to endothelial cells along the length of the arteriole. (
c) Two weeks after induction of adjuvant monoarthritis in the
PAR-2–/– mouse there is marked discrete extravascular cellular staining (scale bar: 50 μm for both
b and
c). (
d) X-gal staining of inflamed synovial tissue excised from the knee joints of four
PAR-2–/– mice shows very dense staining compared with uninflamed tissues from the contralateral knees (scale bar: 5 mm).
