Autoantibodies against Modified Histone Peptides in SLE Patients Are Associated with Disease Activity and Lupus Nephritis (original) (raw)
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Annals of the Rheumatic Diseases, 2010
Objectives In systemic lupus erythematosus (SLE) apoptotic chromatin is present extracellularly, which is most likely the result of disturbed apoptosis and/or insuffi cient removal. Released chromatin, modifi ed during apoptosis, activates the immune system resulting in the formation of autoantibodies. A study was undertaken to identify apoptosis-induced histone modifi cations that play a role in SLE. Methods The lupus-derived monoclonal antibody BT164, recently established by selection using apoptotic nucleosomes, was analysed by ELISA, western blot analysis and immunofl uorescence staining using chromatin, cells, plasma and renal sections. Random peptide phage display and peptide inhibition ELISA were used to identify precisely the epitope of BT164. The reactivity of plasma samples from lupus mice and patients with SLE with the epitope of BT164 was investigated by peptide ELISA. Results The epitope of BT164 was mapped in the N-terminal tail of histone H3 (27-KSAPAT-32) and included the apoptosis-induced trimethylation of K27. siRNA-mediated silencing of histone demethylases in cultured cells resulted in hypermethylation of H3K27 and increased nuclear reactivity of BT164. This apoptosisinduced H3K27me3 is a target for autoantibodies in patients and mice with SLE and is present in plasma and in glomerular deposits. Conclusion In addition to previously identifi ed acetylation of histone H4, H2A and H2B, this study shows that trimethylation of histone H3 on lysine 27 is induced by apoptosis and associated with autoimmunity in SLE. This fi nding is important for understanding the autoimmune response in SLE and for the development of translational strategies.
Autoimmunity to isomerized histone H2B in systemic lupus erythematosus
Autoimmunity, 2012
Histone H2B is a common target of autoantibodies in both spontaneous and drug-induced systemic lupus erythematosus (SLE). Recent studies demonstrate that Asp 25 of histone H2B (H2B) spontaneously converts to an isoaspartic acid (isoAsp) in vivo. Our laboratory has demonstrated that the posttranslational modification of an aspartic acid to an isoaspartic acid within self-peptides renders otherwise ignored peptides immunogenic. Analysis of serum from lupus-prone mice and histone antibody positive SLE patients revealed antibodies specific to the Asp and isoAsp H2B 21-35 peptide, and that the expression of these antibodies is dependent on TLR9. IsoAsp H2B 21-35 is immunogenic in non-autoimmune prone mice and mice lacking the ability to repair isoAsp have significantly reduced levels of antibodies to H2B. Asp H2B 21-35 incubated at physiological temperatures and pH acquires the isoAsp modification, demonstrating that H2B 21-35 is prone to spontaneous isoAsp formation in vivo. Autoimmunity to isoAsp H2B suggests that this form of the autoantigen may be critical in the induction of anti-histone autoantibodies in human SLE and in murine models of disease.
Annals of the Rheumatic Diseases, 2007
Objective: To study the prevalence and course of antichromatin (anti-nucleosome, anti-double-stranded (ds) DNA and anti-histone) and anti-C1q autoantibodies in patients with proliferative lupus nephritis (LN), treated in a randomised controlled trial with either cyclophosphamide or azathioprine plus methylprednisolone. Methods: Autoantibody levels were measured and analysed in 52 patients with proliferative LN, during their first year of treatment. Levels in both treatment arms were compared and associations with clinical, serological and outcome parameters were studied. Results: At study entry, prevalences for anti-nucleosome, anti-dsDNA, anti-histone and anti-C1q autoantibodies were 81%, 96%, 23% and 65%, respectively. Anti-chromatin autoantibodies correlated with each other, but not with anti-C1q levels. If patients were divided for their autoantibody titre at the start of treatment above or below the median, the only significant differences were higher SLE disease activity index with higher anti-nucleosome, and higher creatinine with higher anti-C1q autoantibodies. During the first year, a comparable rapid decline in the levels of anti-nucleosome, anti-dsDNA and anti-C1q autoantibodies was seen in both treatment arms. Antihistone autoantibody levels were low and did not change. Renal flares were not preceded by rises in autoantibody titres. Conclusions: These results indicate that measurement of antichromatin and anti-C1q autoantibodies is useful for diagnosing LN, but not for monitoring disease course.
Biochemical pharmacology, 2003
In recent years, it has become evident that Systemic Lupus Erythematosus (SLE) is a disease characterized by an array of autoantibodies directed against the native nucleosome, its DNA component and/or its histone component. Nuclear antigens are generated and released in vivo during apoptosis. A hallmark of apoptosis is the cleavage of chromatin by caspase-activated DNase. This fragmentation occurs at the internucleosomal level and leads to DNA ladder formation classically associated with apoptosis. Thus, dysregulation of DNA fragmentation might be directly linked to the induction of autoimmunity in SLE. In our studies, activated human lymphoblasts contain high amounts of core histones in their cell lysates after apoptosis induction. This accumulation correlated highly with markers of early apoptosis (Annexin V positive, propidium iodide negative), but not with markers of late apoptosis or necrosis. Interestingly, accumulation of core histones or nucleosomes in cell lysates was detected as early as 30 or 60 min after UV irradiation, whereas phosphatidylserine externalization occurred 2 hr after apoptosis induction. Our results suggest that extranuclear accumulation of core histones is a very early event in apoptosis, preceding the externalization of phagocytosis signals on the outer membrane surface of apoptotically dying lymphoblasts. The following review will discuss these results in a broader perspective which includes our hypothesis of how apoptosis dysregulation during early phases may contribute to the induction of autoimmunity against nuclear autoantigens as seen in SLE. #
Apoptosis-associated acetylation on histone H2B is an epitope for lupus autoantibodies
Molecular Immunology, 2009
Objective: Nucleosomes have been identified as a key autoantigen in systemic lupus erythematosus (SLE). Nucleosomes are present in the circulation due to a disturbed apoptosis and/or an insufficient clearance in SLE. During apoptosis, histones can be modified, thereby making them more immunogenic. Recently, we showed the importance of apoptosis-induced acetylation of histone H4 in the pathogenesis of SLE. The lupus-derived antibody LG11-2 was previously shown to react with the N-terminal tail of histone H2B, which contains amino acid residues that can be modified including phosphorylation of serine 14, known to occur during apoptosis. Here, we evaluate whether apoptosis-induced histone modifications on H2B exist that are targeted by LG11-2 or lupus-derived plasmas. Methods: Immunofluorescence staining and western immunoblot analysis of control, apoptotic and trichostatin A-treated cells/chromatin were performed with monoclonal antibody LG11-2. Reactivity of LG11-2 and plasmas from lupus mice and SLE patients with acetylated and/or phosphorylated H2B peptides was determined in competition ELISA.
Anti-chromatin antibodies in systemic lupus erythematosus: a useful marker for lupus nephropathy
Annals of the Rheumatic Diseases, 2003
Background: Anti-chromatin antibodies have recently been described in patients with systemic lupus erythematosus (SLE) and it has been suggested that their presence is associated with lupus nephritis. Objective: To assess the prevalence and clinical associations of these antibodies in SLE. Methods: The presence of anti-chromatin antibodies in 100 patients with SLE was investigated by an enzyme linked immunosorbent assay (ELISA). To determine the specificity of these antibodies, 100 patients with primary Sjögren's syndrome, 30 with primary antiphospholipid syndrome (APS), 10 with systemic sclerosis, and 100 normal controls were also tested. Results: Positive levels were detected in 69/100 (69%) patients with SLE. In contrast, they were found in only 8/100 (8%) of those with primary Sjögren's syndrome, in 1/10 (10%) with systemic sclerosis, in 2/30 (7%) with primary APS, and in none of the 100 healthy controls. Patients with anti-chromatin antibodies had a twofold higher prevalence of lupus nephropathy than those without these antibodies (58% v 29%, p<0.01). A significant correlation was found between the levels of anti-chromatin antibodies and disease activity score as measured by the European Consensus Lupus Activity Measurement (ECLAM; p=0.011). Conclusions: The measurement of anti-chromatin antibodies appears to be a useful addition to the laboratory tests that can help in the diagnosis and treatment of SLE. These antibodies are both sensitive and specific for SLE, and are a useful marker for an increased risk of lupus nephritis.
Journal of immunology research, 2014
Autoantibodies directed to chromatin components date back to the discovery of the LE cell and the LE cell phenomenon circa 1950, and subsequent evidence that major components of that reaction were chromatin components and histones in particular. Over time, immunoassays ranging from ELISA and line immunoassays to more modern bead-based assays incorporated histone and DNA mixtures, purified histones, and purified nucleosomes leading to a more thorough understanding of the genesis and pathogenetic relationships of antibodies to chromatin components in systemic lupus erythematosus and other autoimmune conditions. More recently, interest has focussed on other components of chromatin such as high mobility group (HMG) proteins both as targets of B cell responses and pro-inflammatory mediators. This review will focus on immunoassays that utilize chromatin components, their clinical relationships, and newer evidence implicating HMG proteins and DNA neutrophil extracellular traps (NETs) as im...
Molecular Immunology, 1987
The sera of patients with systemic lupus erythematosus (SLE) and drug-induced lupus (DIL) were used to study the antigenic regions of histone 1 (Hl) that bind antibodies in these sera. ELISA and immunoblotting techniques using enzymatically and chemically derived peptides of Hl showed that the major antigenic domain is in the carboxyl (C) terminus. None of the 24 SLE or 11 DIL sera bound to the central hydrophobic polypeptide by ELISA. The reactivity of DIL sera with the purified Hl peptides was similar to that observed with SLE sera. This observation suggests a common immune pathway for DIL and SLE.