5-Aminosalicylic acid abrogates T-cell proliferation by blocking interleukin-2 production in peripheral blood mononuclear cells.
The antiinflammatory agent sulfasalazine (SS) is prescribed to treat Crohn's disease, ulcerative colitis and rheumatoid arthritis. Activated T cells are present within diseased mucosal and synovial sites. We tested whether SS or its metabolites 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP) inhibited the T-cell activation products interleukin 2 (IL-2) and interleukin 2 receptor alpha-chain (IL-2R alpha). Experiments were performed in phytohemaglutinin- and phorbol ester-stimulated peripheral blood mononuclear cells. Radioactive thymidine and leucine incorporation assayed DNA and protein synthesis, respectively. Enzyme-linked immunosorbent assay and Northern blot analysis measured IL-2 and IL-2R alpha. Lactate dehydrogenase release determined cell viability, and intracellular free calcium was measured by an indole fluorescent indicator. SS and 5-ASA, but not SP, inhibited T-cell proliferation and protein synthesis in phytohemaglutinin- and phorbol ester-stimulated peripheral blood monomuclear cells. 5-ASA (625 microM) markedly reduced culture supernatant IL-2 protein levels by 92% and steady-state IL-2 messenger RNA levels 4.4-fold at 24 and 18 hr, respectively. The supplementation of IL-2 restored T-cell proliferation only in 5-ASA-treated cultures. SS, 5-ASA and SP did not alter intracellular calcium accumulation after mitogenic stimulation. SS and 5-ASA (625 microM) caused 71% and 37% cytotoxicity, respectively, in 72-hr cultures. 5-ASA inhibits T-cell proliferation in part by blocking IL-2 messenger RNA accumulation and protein production downstream of the rise in cytosolic calcium. Inhibition of IL-2 production is an additional mechanism of action for 5-ASA.
Stevens
C
C
Department of Medicine, Beth Israel Hospital, Boston, Massachusetts.
Lipman
M
M
Fabry
S
S
Moscovitch-Lopatin
M
M
Almawi
W
W
Keresztes
S
S
Peppercorn
M A
MA
Strom
T B
TB
D000636:Aminosalicylic Acids / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D019804:Mesalamine; D012333:RNA, Messenger / Q000235:genetics; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013427:Sulfapyridine / Q000494:pharmacology; D012460:Sulfasalazine / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects*
D000636:Aminosalicylic Acids; D007376:Interleukin-2; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D012460:Sulfasalazine; D019804:Mesalamine; D002118:Calcium; D013427:Sulfapyridine