DNA-anti-DNA immune complexes. Antibody protection of a discrete DNA fragment from DNase digestion in vitro.

Emlen, Woodruff; Ansari, Raheel M.; Burdick, G

doi:10.1172/jci111400

Cited by 46 publications

(25 citation statements)

References 22 publications

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“…The sera of other SLE patients (group 2) have high titers of Abs that bind to NETs and thus protect them from DNase1. This is in agreement with the observation that anti-DNA Abs protect DNA from DNase fragmentation in vitro (30). Interestingly, mutations (21) and polymorphisms in DNase1 (31) have been associated with SLE.…”

Section: Discussionsupporting

confidence: 90%

Impairment of neutrophil extracellular trap degradation is associated with lupus nephritis

Hakkim¹,

Fürnrohr

Amann

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

1,262

1,206

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Systemic lupus erythematosus (SLE) is an autoimmune disease in which patients develop autoantibodies to DNA, histones, and often to neutrophil proteins. These form immune complexes that are pathogenic and may cause lupus nephritis. In SLE patients, infections can initiate flares and are a major cause of mortality. Neutrophils respond to infections and release extracellular traps (NETs), which are antimicrobial and are made of DNA, histones, and neutrophil proteins. The timely removal of NETs may be crucial for tissue homeostasis to avoid presentation of self-antigens. We tested the hypothesis that SLE patients cannot clear NETs, contributing to the pathogenesis of lupus nephritis. Here we show that serum endonuclease DNase1 is essential for disassembly of NETs. Interestingly, a subset of SLE patients’ sera degraded NETs poorly. Two mechanisms caused this impaired NET degradation: ( i ) the presence of DNase1 inhibitors or ( ii ) anti-NET antibodies prevented DNase1 access to NETs. Impairment of DNase1 function and failure to dismantle NETs correlated with kidney involvement. Hence, identification of SLE patients who cannot dismantle NETs might be a useful indicator of renal involvement. Moreover, NETs might represent a therapeutic target in SLE.

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Section: Discussionsupporting

confidence: 90%

Impairment of neutrophil extracellular trap degradation is associated with lupus nephritis

Hakkim¹,

Fürnrohr

Amann

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

1,262

1,206

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“…Rat DNase I carries two mutations (E 13 to D and V 67 to I) responsible for the decrease in actin-binding of rat DNase I [3]. Contrary to the findings of Emlen et al [29] and Pucetti et al [30], we were unable to demonstrate any inhibitory or protective effect of anti-DNA antibodies on the reaction of DNase with DNA in agarose gels. Emlen et al [29] have shown that a 35-45 base pair (bp) DNA fragment in SLE sera is protected from DNase digestion and remains bound to antibody, thereby forming a small, DNase-resistant DNA-anti-DNA immune complex.…”

contrasting

confidence: 99%

Measurement of deoxyribonuclease I (DNase) in the serum and urine of systemic lupus erythematosus (SLE)-prone NZB/NZW mice by a new radial enzyme diffusion assay

Macanović

Lachmann

1997

Clinical and Experimental Immunology

104

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SUMMARYA new radial enzyme diffusion (RED) method for the measurement of DNase activity in serum and urine is described. The sensitivity of the assay is in the range of 15 . 6-500 ng/ml. The assay is based on the hydrolysis of double-stranded (ds) DNA (or nucleosomes) in agarose. The specificity of the reaction for DNase I was established by showing that either EDTA in the reaction buffer or G-actin abolished DNase activity. Being a functional assay, RED has advantages over radioimmunoassay (RIA) or ELISA, since antigenic assays may also measure complexes of DNase with actin. This method was used to measure DNase activity in the sera and urine of lupus-prone mice (NZB/NZW F 1 hybrids, aged 4-6 weeks). Serum DNase activity in these mice was significantly lower (mean 9 ng/ml) than in control, normal mice of the same age and sex (mean 37 ng/ml). Concentration of DNase in the urine of 4-6-week-old female NZB/NZW F 1 hybrids (24 ng/ml) was significantly lower then in control mice (521 ng/ml). The RED method was used to measure the concentration of actin as the DNase inhibitor in serum. G-actin in the presence of ATP binds DNase and inhibits its nucleolytic activity. Since ATP is necessary for the actin inhibition of DNase I, this shows that there is actin as well as DNase I in the serum. Actin is not only ATP-dependent, but also heat-labile. Heating the sera for 10 min at 50ЊC increases DNase activity. This is an alternative method for measuring the concentration of actin in the serum. An almost identical estimate of actin concentration in sera of normal mice was found from the difference of DNase activity in the presence or absence of ATP (mean actin concentration ¼ 21 ng/ml) or from the difference of DNase activity in heated and non-heated serum (mean actin concentration 18 ng/ml). We were not able to demonstrate DNase inhibitors in the urine of either control or NZB/W F 1 hybrid mice.

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“…Similarly, neither plasma DNA binding proteins (18) nor bound anti-DNA antibodies, if present, could easily account for the observed plasma DNA size distribution. Although anti-dsDNA antibodies partially protect DNA from nucleases, the length protected is only about 40 bp ( 19). Moreover, these explanations would not account for the reactivity of plasma DNA with antihistone antibody.…”

Section: Discussionmentioning

confidence: 98%

Endogenous circulating DNA in systemic lupus erythematosus. Occurrence as multimeric complexes bound to histone.

Rumore¹,

Steinman²

1990

J. Clin. Invest.

346

187

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Little is known about endogenous systemic lupus erythematosus (SLE) plasma DNA even though it is the presumed precursor of DNA-containing immune complexes, thought to play a central role in lupus glomerulonephritis. DNA purified from SLE plasma formed discrete bands, corresponding to sizes of about 150-200, 400, 600, and 800 bp, closely resembling the characteristic 200 bp "ladder" found with oligonucleosomal (ON) DNA. By radiolabeling DNA while in whole plasma, the very small amounts present could be further characterized. All of 24 such specimens formed two or more discrete bands on 6% PAGE. Detergent treatment of plasma resulted in a DNA migration pattern similar to that of purified DNA, suggesting disruption of DNA-protein complexes. DNA purified from authentic ON and detergent-treated ON behaved similarly. A significant portion of DNA, labeled in SLE plasma could be specifically immunoprecipitated with monoclonal antihistone antibody as was the case with ON. These immunoprecipitates, when redissolved, exhibited the expected size distribution upon PAGE. It is concluded that DNA in SLE plasma occurs as a series of multimeric complexes, at least a portion of which is noncovalently bound to histone. These results are consistent with an ON-like structure for SLE plasma DNA as had been suggested by theoretical considerations and may have important implications for its immunologic behavior in SLE and perhaps other disorders. (J. Clin. Invest. 1990.86:69-74.)

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DNA-anti-DNA immune complexes. Antibody protection of a discrete DNA fragment from DNase digestion in vitro.

Cited by 46 publications

References 22 publications

Impairment of neutrophil extracellular trap degradation is associated with lupus nephritis

Impairment of neutrophil extracellular trap degradation is associated with lupus nephritis

Measurement of deoxyribonuclease I (DNase) in the serum and urine of systemic lupus erythematosus (SLE)-prone NZB/NZW mice by a new radial enzyme diffusion assay

Endogenous circulating DNA in systemic lupus erythematosus. Occurrence as multimeric complexes bound to histone.

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