Reversing interleukin-2 inhibition mediated by anti-double-stranded DNA autoantibody ameliorates glomerulonephritis in MRL-lpr/lpr mice.
OBJECTIVE
Our previous study demonstrated that anti-double-stranded DNA (anti-dsDNA) antibodies involved in lupus nephritis down-regulate the production of interleukin-2 (IL-2) in T cells, which in turn, contributes to the defective production of cytotoxic cells and to activation-induced cell death in vitro. To reveal novel molecular targets for lupus therapy, the molecular mechanisms of IL-2 down-regulation by anti-dsDNA were studied.


METHODS
Anti-dsDNA monoclonal antibody (mAb) 9D7 was used to study the molecular mechanisms of IL-2 production in vitro. Treatment with arginine-rich peptide, a penetration inhibitor, was used to verify the effect of internalization of anti-dsDNA on the production of IL-2. The signaling pathway for IL-2 expression induced by anti-dsDNA was analyzed by using kinase inhibitors. The therapeutic effects of these inhibitors were evaluated in MRL-lpr/lpr mice.


RESULTS
Inhibition of IL-2 production in activated Jurkat cells and human T cells pretreated with mAb 9D7 was reversed by treatment with the arginine-rich peptide. Levels of pAkt and phosphorylated glycogen synthase kinase 3 (pGSK-3) were reduced in activated Jurkat cells that had been pretreated with mAb 9D7. The inhibition of IL-2 production by mAb 9D7 was counteracted by pretreating the cells with LiCl (a GSK-3 inhibitor). However, IL-2 reduction was not recovered in the cells pretreated with ERK and JNK inhibitors. Furthermore, MRL-lpr/lpr mice injected with LiCl or with arginine-rich peptide restored the IL-2 production and reduced the manifestations of lupus.


CONCLUSIONS
These findings suggest that penetration of T cells by anti-dsDNA may inhibit IL-2 production by activating GSK-3. Moreover, blocking GSK-3 activation as well as inhibiting anti-dsDNA penetration is a potential therapeutic approach for lupus.
Song
Ying-Chyi
YC
National Yang-Ming University, Taipei, Taiwan.
Tang
Shye-Jye
SJ
Lee
Tai-Ping
TP
Hung
Wen-Chien
WC
Lin
Shu-Chi
SC
Tsai
Chang-Youh
CY
Ng
Wailap Victor
WV
Wu
Ming-Fang
MF
Sun
Kuang-Hui
KH
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology; D001323:Autoantibodies / Q000235:genetics / Q000276:immunology*; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005921:Glomerulonephritis / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology*; D051379:Mice; D019463:Mice, Inbred MRL lpr; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D007376:Interleukin-2; D004247:DNA