Stimulation of the secretion of latent cysteine proteinase activity by tumor necrosis factor alpha and interleukin-1.
OBJECTIVE
Cultured synovial fibroblast-like cells from 3 patients with rheumatoid arthritis (RA) and 3 patients with osteoarthritis (OA) were evaluated for their potential to secrete cysteine proteinases spontaneously and after stimulation by tumor necrosis factor alpha (TNF alpha) or interleukin-1 (IL-1).


METHODS
Culture media and cell lysates were analyzed before and after high performance liquid chromatography (HPLC) using the enzymatic substrate, Z-Phe-Arg-AMC, and by immunoblotting with anti-cathepsin B antiserum. Immunolocalization of cathepsin B was studied on cell monolayers.


RESULTS
Latent cysteine proteinase activity was found to be secreted spontaneously by cultured synovial fibroblast-like cells. This activity was increased after treatment with either TNF alpha or IL-1. Stimulated protease activity was eluted by HPLC at a peak coincident with that of purified cathepsin B. By immunoblot, cell supernatants contained a 43-kd form of cathepsin B, while cell lysates contained a 30-kd form, consistent, respectively, with cathepsin B before and after cleavage of its propeptide. An intracellular increase in cathepsin B after treatment with TNF alpha was also seen with immunohistochemical studies.


CONCLUSIONS
TNF alpha (in the 6 cases studied) and IL-1 (in 4 cases) stimulated the secretion of a latent cysteine proteinase activity from synovial fibroblast-like cells, which appears to represent primarily cathepsin B.
Department of Biochemistry, CHRU, Lille, France.
G
G
Huet
R M
RM
Flipo
C
C
Colin
A
A
Janin
B
B
Hemon
M
M
Collyn-d'Hooghe
R
R
Lafyatis
B
B
Duquesnoy
P
P
Degand
D001172:Arthritis, Rheumatoid / Q000473:pathology; D002401:Cathepsin B / Q000737:chemistry; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000494:pharmacology*; D010003:Osteoarthritis / Q000473:pathology; D013583:Synovial Membrane / Q000166:cytology / Q000201:enzymology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D003546:Cysteine Endopeptidases; D002401:Cathepsin B