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Clinical and serologic manifestations of autoimmune disease in MRL-lpr/lpr mice lacking nitric oxide synthase type 2.

Gilkeson GS, Mudgett JS, Seldin MF, Ruiz P, Alexander AA, Misukonis MA, Pisetsky DS, Weinberg JB - J. Exp. Med. (1997)

Bottom Line: In previous studies, we showed that inhibiting NO production with the nonselective nitric oxide synthase (NOS) inhibitor NG-monomethyl-arginine reduced glomerulonephritis, arthritis, and vasculitis in MRL-lpr/lpr mice.MRL-lpr/lpr littermates homozygous for disrupted NOS2 (-/-), heterozygous for disrupted NOS2 (+/-), or wildtype (+/+) were derived for this study.There was no detectable NOS2 protein by immunoblot analysis of the spleen, liver, kidney, and peritoneal macrophages of the (-/-) animals, whereas that of (+/+) was high and (+/-) intermediate.

View Article: PubMed Central - PubMed

Affiliation: Ralph H. Johnson Veterans Affairs Medical Center, Medical University of South Carolina, Charleston 29425, USA.

ABSTRACT
Nitric oxide (NO) is an important mediator of the inflammatory response. MRL-lpr/lpr mice overexpress inducible nitric oxide synthase (NOS2) and overproduce NO in parallel with the development of an autoimmune syndrome with a variety of inflammatory manifestations. In previous studies, we showed that inhibiting NO production with the nonselective nitric oxide synthase (NOS) inhibitor NG-monomethyl-arginine reduced glomerulonephritis, arthritis, and vasculitis in MRL-lpr/lpr mice. To define further the role of NO and NOS2 in disease in MRL-lpr/lpr mice, mice with targeted disruption of NOS2 were produced by homologous recombination and bred to MRL-lpr/lpr mice to the N4 generation. MRL-lpr/lpr littermates homozygous for disrupted NOS2 (-/-), heterozygous for disrupted NOS2 (+/-), or wildtype (+/+) were derived for this study. Measures of NO production were markedly decreased in the MRL-lpr/lpr (-/-) mice compared with MRL-lpr/lpr (+/+) mice, with intermediate production by the MRL-lpr/lpr (+/-) mice. There was no detectable NOS2 protein by immunoblot analysis of the spleen, liver, kidney, and peritoneal macrophages of the (-/-) animals, whereas that of (+/+) was high and (+/-) intermediate. The (-/-) mice developed glomerular and synovial pathology similar to that of the (+/-) and (+/+) mice. However, (-/-) mice and (+/-) mice had significantly less vasculitis of medium-sized renal vessels than (+/+) mice. IgG rheumatoid factor levels were significantly lower in the (-/-) mice as compared with (+/+) mice, but levels of anti-DNA antibodies were comparable in all groups. Our findings show that NO derived from NOS2 has a variable impact on disease manifestations in MRL-lpr/lpr mice, suggesting heterogeneity in disease mechanisms.

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(A and B) Anti-DNA and anti-Ig rheumatoid factor antibody activity in sera from NOS2-modified MRL–lpr/lpr mice. 20-wk-old mice  were examined. A shows results from experiments testing sera for anti-ss-DNA antibody and anti-dsDNA antibody activity, and B shows results from experiments testing sera for IgG and IgM anti-Ig (rheumatoid factor) activity. The bars display the means and one standard deviation.
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Figure 5: (A and B) Anti-DNA and anti-Ig rheumatoid factor antibody activity in sera from NOS2-modified MRL–lpr/lpr mice. 20-wk-old mice were examined. A shows results from experiments testing sera for anti-ss-DNA antibody and anti-dsDNA antibody activity, and B shows results from experiments testing sera for IgG and IgM anti-Ig (rheumatoid factor) activity. The bars display the means and one standard deviation.

Mentions: Autoimmune disease in MRL–lpr/lpr mice is associated with production of a variety of autoantibodies that are observed in both human rheumatoid arthritis and systemic lupus erythematosus (1–3). Therefore, we determined whether MRL–lpr/lpr mice of various NOS2 genotypes displayed qualitative or quantitative differences in autoantibody production. As shown in Fig. 5 A, serum levels of antibodies to ss or dsDNA did not differ among the various mice, although there was a shift in the isotype of anti-DNA antibodies produced. The IgG1/IgG3 ratio of anti-DNA antibodies was higher in the (−/−) than in (+/+) mice (1.31 versus 0.39). In contrast with anti-DNA antibody levels, RF levels differed among the MRL–lpr/lpr mice of various NOS2 genotypes. The (−/−) mice produced significantly less IgG RF and IgM RF than did (+/+) mice (Fig. 5 B). IgG3 rheumatoid factor activity (known to be associated with small vessel, but not medium vessel vasculitis in MRL–lpr/lpr mice; reference 29), was similar in the three groups of mice [(+/+), 0.733 ± 0.215; (+/−), 0.633 ± 0.362; and (−/−), 0.781 ± 0.278]. Total serum IgG and IgM were similar in the three groups as were serum levels of anti-Sm and anti-La antibodies (results not shown).


Clinical and serologic manifestations of autoimmune disease in MRL-lpr/lpr mice lacking nitric oxide synthase type 2.

Gilkeson GS, Mudgett JS, Seldin MF, Ruiz P, Alexander AA, Misukonis MA, Pisetsky DS, Weinberg JB - J. Exp. Med. (1997)

(A and B) Anti-DNA and anti-Ig rheumatoid factor antibody activity in sera from NOS2-modified MRL–lpr/lpr mice. 20-wk-old mice  were examined. A shows results from experiments testing sera for anti-ss-DNA antibody and anti-dsDNA antibody activity, and B shows results from experiments testing sera for IgG and IgM anti-Ig (rheumatoid factor) activity. The bars display the means and one standard deviation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199001&req=5

Figure 5: (A and B) Anti-DNA and anti-Ig rheumatoid factor antibody activity in sera from NOS2-modified MRL–lpr/lpr mice. 20-wk-old mice were examined. A shows results from experiments testing sera for anti-ss-DNA antibody and anti-dsDNA antibody activity, and B shows results from experiments testing sera for IgG and IgM anti-Ig (rheumatoid factor) activity. The bars display the means and one standard deviation.
Mentions: Autoimmune disease in MRL–lpr/lpr mice is associated with production of a variety of autoantibodies that are observed in both human rheumatoid arthritis and systemic lupus erythematosus (1–3). Therefore, we determined whether MRL–lpr/lpr mice of various NOS2 genotypes displayed qualitative or quantitative differences in autoantibody production. As shown in Fig. 5 A, serum levels of antibodies to ss or dsDNA did not differ among the various mice, although there was a shift in the isotype of anti-DNA antibodies produced. The IgG1/IgG3 ratio of anti-DNA antibodies was higher in the (−/−) than in (+/+) mice (1.31 versus 0.39). In contrast with anti-DNA antibody levels, RF levels differed among the MRL–lpr/lpr mice of various NOS2 genotypes. The (−/−) mice produced significantly less IgG RF and IgM RF than did (+/+) mice (Fig. 5 B). IgG3 rheumatoid factor activity (known to be associated with small vessel, but not medium vessel vasculitis in MRL–lpr/lpr mice; reference 29), was similar in the three groups of mice [(+/+), 0.733 ± 0.215; (+/−), 0.633 ± 0.362; and (−/−), 0.781 ± 0.278]. Total serum IgG and IgM were similar in the three groups as were serum levels of anti-Sm and anti-La antibodies (results not shown).

Bottom Line: In previous studies, we showed that inhibiting NO production with the nonselective nitric oxide synthase (NOS) inhibitor NG-monomethyl-arginine reduced glomerulonephritis, arthritis, and vasculitis in MRL-lpr/lpr mice.MRL-lpr/lpr littermates homozygous for disrupted NOS2 (-/-), heterozygous for disrupted NOS2 (+/-), or wildtype (+/+) were derived for this study.There was no detectable NOS2 protein by immunoblot analysis of the spleen, liver, kidney, and peritoneal macrophages of the (-/-) animals, whereas that of (+/+) was high and (+/-) intermediate.

View Article: PubMed Central - PubMed

Affiliation: Ralph H. Johnson Veterans Affairs Medical Center, Medical University of South Carolina, Charleston 29425, USA.

ABSTRACT
Nitric oxide (NO) is an important mediator of the inflammatory response. MRL-lpr/lpr mice overexpress inducible nitric oxide synthase (NOS2) and overproduce NO in parallel with the development of an autoimmune syndrome with a variety of inflammatory manifestations. In previous studies, we showed that inhibiting NO production with the nonselective nitric oxide synthase (NOS) inhibitor NG-monomethyl-arginine reduced glomerulonephritis, arthritis, and vasculitis in MRL-lpr/lpr mice. To define further the role of NO and NOS2 in disease in MRL-lpr/lpr mice, mice with targeted disruption of NOS2 were produced by homologous recombination and bred to MRL-lpr/lpr mice to the N4 generation. MRL-lpr/lpr littermates homozygous for disrupted NOS2 (-/-), heterozygous for disrupted NOS2 (+/-), or wildtype (+/+) were derived for this study. Measures of NO production were markedly decreased in the MRL-lpr/lpr (-/-) mice compared with MRL-lpr/lpr (+/+) mice, with intermediate production by the MRL-lpr/lpr (+/-) mice. There was no detectable NOS2 protein by immunoblot analysis of the spleen, liver, kidney, and peritoneal macrophages of the (-/-) animals, whereas that of (+/+) was high and (+/-) intermediate. The (-/-) mice developed glomerular and synovial pathology similar to that of the (+/-) and (+/+) mice. However, (-/-) mice and (+/-) mice had significantly less vasculitis of medium-sized renal vessels than (+/+) mice. IgG rheumatoid factor levels were significantly lower in the (-/-) mice as compared with (+/+) mice, but levels of anti-DNA antibodies were comparable in all groups. Our findings show that NO derived from NOS2 has a variable impact on disease manifestations in MRL-lpr/lpr mice, suggesting heterogeneity in disease mechanisms.

Show MeSH
Related in: MedlinePlus