Effect of overexpression of human Cu/Zn-SOD on activation-induced lymphocyte proliferation and apoptosis.
The process of lymphocyte proliferation and apoptosis is known to be linked to oxidative stress. In the present study, we have used a new transgenic mouse model to investigate the effect of human Cu/Zn superoxide dismutase (Cu/Zn-SOD) overexpression on activation-induced lymphocytes proliferation and apoptosis. Cu/Zn-SOD activity was 3.5-fold higher in the spleen of the transgenic mice overexpressing Cu/Zn-SOD (Tg-Cu/Zn-SOD) compared to the wild-type littermates. Proliferative response of lymphocytes to lipopolysaccharide (LPS), Concanavalin A (Con A), and anti-CD3 was measured by [3H]-thymidine incorporation. Activation-induced apoptosis was determined by incubating the T cells with anti-CD3 (primary stimulus) for 72 h, followed by restimulation with Con A (secondary stimulus) for various times. Apoptosis was assessed by measuring DNA fragmentation using a spectrofluorimetric assay and monitoring the expression of the specific apoptotic markers (Fas/CD95 receptor and Fas/CD95 ligand (Fas-L) using flow cytometry. There was no significant difference in proliferative response of lymphocytes to LPS, Con A, or anti-CD3 in transgenic mice overexpressing human Cu/Zn superoxide dismutase (Tg-Cu/Zn-SOD) compared to wild-type littermates. In addition, no significant difference was observed in lymphocyte populations and subsets between Tg-Cu/Zn-SOD mice and wild-type littermates. However, splenic T cells from Tg-Cu/Zn-SOD mice exhibited a significantly (p <.05) higher level of activation-induced DNA fragmentation than T cells from wild-type littermates. The increase in DNA fragmentation was paralleled with an increase in the proportion of T cells expressing Fas and Fas-L molecules. The possible consequences of Cu/Zn-SOD overproduction on activation-induced apoptosis are discussed.
Pahlavani
M A
MA
South Texas Veterans Health Care System, Audie L. Murphy Veterans Hospital, and Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78284, USA. pahlavani@uthscsa.edu
Mele
J F
JF
Richardson
A
A
D000818:Animals; D000938:Antigen-Presenting Cells; D017209:Apoptosis / Q000502:physiology*; D002455:Cell Division; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D053222:Fas Ligand Protein; D005434:Flow Cytometry; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D013154:Spleen / Q000201:enzymology; D013482:Superoxide Dismutase / Q000096:biosynthesis* / Q000235:genetics; D013601:T-Lymphocytes / Q000502:physiology*; D019014:fas Receptor / Q000378:metabolism
C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D019014:fas Receptor; D003208:Concanavalin A; D013482:Superoxide Dismutase