IL-2-induced tumor necrosis factor (TNF)-beta expression: further analysis in the IL-2 knockout model, and comparison with TNF-alpha, lymphotoxin-beta, TNFR1 and TNFR2 modulation.
IL-2 induces the stimulation of inflammatory and immune reactions, and the apoptosis of antigen-activated cells. However, the molecular basis of these pleiotropic functions is largely unknown. We have previously reported that IL-2 induces genes involved in cytoskeleton organization, oncogene regulation and transcriptional control. In an IL-2-dependent cell line, we have also shown that IL-2 induces tumor necrosis factor (TNF)-beta mRNA through the Jak-STAT pathway. Here, we first demonstrate in vitro that IL-2 induces mature and partially spliced TNF-beta mRNA in the splenocytes and lymph node cells of both IL-2(-/-) and IL-2(+/-) mice. Under the same experimental conditions, IL-2 is seen to induce TNF-alpha mRNA. mRNA expression is followed by semiquantitative RT-PCR and this analysis is then extended in vivo by studying different lymphoid organs from IL-2(-/-)animals. Strikingly, the expression of TNF-beta mRNA is noted to be extremely low in the spleens and lymph nodes of IL-2(-/-) mice. Similarly, TNF-alpha, lymphotoxin (LT)-beta, TNFR1 and TNFR2 mRNA levels are also low in the spleens of IL-2(-/-) animals, whereas IFN-gamma and IL-4 mRNA levels remain unaffected in these animals. The experimental values are significantly different (P < or = 0.05) from those of control IL-2(+/-) animals. Western blot analysis of TNF-alpha expression confirmed and extended the results at the protein level. For the first time, we demonstrate that IL-2 directly or indirectly regulates genes of the TNF-TNFR family in secondary lymphoid organs. Furthermore, IL-2(-/-) animals in which thymopoiesis is unaffected show normal expression of these genes. Altogether, our data further define the pleiotropic effects of IL-2 at the molecular level.
Reddy
J
J
Unité d'Immunogénétique Cellulaire, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France.
Chastagner
P
P
Fiette
L
L
Liu
X
X
Thèze
J
J
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D007376:Interleukin-2 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000166:cytology; D008233:Lymphotoxin-alpha / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D053308:Lymphotoxin-beta; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000096:biosynthesis; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D015703:Antigens, CD; D007376:Interleukin-2; C505887:Ltb protein, mouse; D008233:Lymphotoxin-alpha; D053308:Lymphotoxin-beta; D008565:Membrane Proteins; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha