RESUMEN

Anti-dsDNA antibodies are pathogenically heterogeneous, implying distinct origins and antigenic properties. Unexpectedly, during the clinical and molecular characterization of autoantibodies to the endonuclease DNase1L3 in patients with systemic lupus erythematosus (SLE), we identified a subset of neutralizing anti-DNase1L3 antibodies previously catalogued as anti-dsDNA. Based on their variable heavy-chain (VH) gene usage, these antibodies can be divided in two groups. One group is encoded by the inherently autoreactive VH4-34 gene segment, derives from anti-DNase1L3 germline-encoded precursors, and gains cross-reactivity to dsDNA - and some additionally to cardiolipin - following somatic hypermutation. The second group, originally defined as nephritogenic anti-dsDNA antibodies, is encoded by diverse VH gene segments. Although affinity maturation results in dual reactivity to DNase1L3 and dsDNA, their binding efficiencies favor DNase1L3 as the primary antigen. Clinical, transcriptional and monoclonal antibody data support that cross-reactive anti-DNase1L3/dsDNA antibodies are more pathogenic than single reactive anti-dsDNA antibodies. These findings point to DNase1L3 as the primary target of a subset of antibodies classified as anti-dsDNA, shedding light on the origin and pathogenic heterogeneity of antibodies reactive to dsDNA in SLE.

Asunto(s)

Lupus Eritematoso Sistémico , Humanos , Lupus Eritematoso Sistémico/genética , Autoanticuerpos , Anticuerpos Antinucleares/genética , ADN/metabolismo , Anticuerpos Monoclonales , Endodesoxirribonucleasas/genética

RESUMEN

Introduction: It is documented that a series of autoantibodies can be detected with increased frequency in women with recurrent pregnancy loss (RPL) and they may impact the pregnancy prognosis negatively. It is unknown whether the autoantibodies per se or the basic immune disturbances underlying autoantibody production, are the reason for this association. Our group has previously found that some genetically determined immunological biomarkers are associated with RPL and the same biomarkers are also in various degrees known to predispose to autoantibody production. The aim of this study was to clarify whether the RPL-associated immunogenetic biomarkers are associated with positivity for three major classes of autoantibodies associated with RPL. Methods: In 663 patients with RPL in whom we had results for HLA-DRB1 typing and plasma mannose-binding lectin (p-MBL) measurement, it was investigated whether there is a correlation between positivity for the autoantibodies: anticardiolipin antibodies, ß2 glycoprotein I antibodies, and lupus anticoagulant (jointly called antiphospholipid antibodies), thyroid-peroxidase antibodies, and antinuclear antibodies and each of the HLA-DRB1 alleles HLA-DRB1*03 or HLA-DRB1*07 either alone or in combination with low p-MBL defined as ≤500 µg/l. Results: Although slightly higher frequencies of positivity of two or more autoantibodies were seen in patients with either p-MBL ≤500 µg/l or being positive for HLA-DRB1*03, none were significantly associated. However, in patients with the combination of low p-MBL and HLA-DRB1*03, presence of at least one autoantibody was significantly more frequent than in patients with no such combination (OR= 2.4; 95% CI 1.2-5.0, p = 0.01). In an analysis of which autoantibodies were most strongly associated with the low p-MBL/HLA-DRB1*03 combination, antinuclear antibodies were significantly more frequent in these patients (OR 2.0; 95% CI 1.0-3.9, p=0.05) whereas the other autoantibodies were also positively but more weakly associated with this combination. Discussion: In conclusion, to clarify the pathogenetic background, underlying immunogenetic factors should be examined in autoantibody positive RPL patients (as well as other patients with autoimmune diseases) but the genetic background may be complex.

Asunto(s)

Aborto Habitual , Anticuerpos Antinucleares , Cadenas HLA-DRB1 , Femenino , Humanos , Embarazo , Aborto Habitual/genética , Anticuerpos Antinucleares/genética , Autoanticuerpos , Cadenas HLA-DRB1/genética , Lectinas de Unión a Manosa/genética , Fenotipo

RESUMEN

Systemic lupus erythematosus is a chronic disease characterized by autoantibodies, renal and cutaneous disease, and immune complex formation. Emerging evidence suggests that aberrant DNA repair is an underlying mechanism of lupus development. We previously showed that the POLBY265C/C mutation, which results in development of an aberrant immune repertoire, leads to lupus-like disease in mice. To address whether the hematopoietic compartment is sufficient for lupus development, we transplanted bone marrow cells from POLBY265C/C and POLB+/+ into wild-type congenic mice. Only mice transplanted with the POLBY265C/C bone marrow develop high levels of antinuclear antibodies and renal disease. In conclusion, we show that the hematopoietic compartment harvested from the POLBY265C/C mice is sufficient for development of autoimmune disease.

Asunto(s)

ADN Polimerasa beta/metabolismo , Lupus Eritematoso Sistémico , Animales , Anticuerpos Antinucleares/genética , Autoanticuerpos/genética , Lupus Eritematoso Sistémico/genética , Ratones , Mutación

RESUMEN

The anti-La mab 312B, which was established by hybridoma technology from human-La transgenic mice after adoptive transfer of anti-human La T cells, immunoprecipitates both native eukaryotic human and murine La protein. Therefore, it represents a true anti-La autoantibody. During maturation, the anti-La mab 312B acquired somatic hypermutations (SHMs) which resulted in the replacement of four aa in the complementarity determining regions (CDR) and seven aa in the framework regions. The recombinant derivative of the anti-La mab 312B in which all the SHMs were corrected to the germline sequence failed to recognize the La antigen. We therefore wanted to learn which SHM(s) is (are) responsible for anti-La autoreactivity. Humanization of the 312B ab by grafting its CDR regions to a human Ig backbone confirms that the CDR sequences are mainly responsible for anti-La autoreactivity. Finally, we identified that a single amino acid replacement (D > Y) in the germline sequence of the CDR3 region of the heavy chain of the anti-La mab 312B is sufficient for anti-La autoreactivity.

Asunto(s)

Anticuerpos Antinucleares/genética , Autoanticuerpos/genética , Hipermutación Somática de Inmunoglobulina/genética , Secuencia de Aminoácidos , Aminoácidos/genética , Aminoácidos/metabolismo , Anticuerpos Antinucleares/inmunología , Anticuerpos Antinucleares/metabolismo , Autoanticuerpos/química , Autoanticuerpos/inmunología , Autoanticuerpos/metabolismo , Autoinmunidad/genética , Regiones Determinantes de Complementariedad/genética , Regiones Determinantes de Complementariedad/inmunología , Regiones Determinantes de Complementariedad/metabolismo , Epítopos/genética , Epítopos/inmunología , Células HeLa , Humanos , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/metabolismo , Análisis de Secuencia de Proteína

RESUMEN

Autoimmunity may have its origins of early repertoire selection in developmental B cells. Such a primary repertoire is probably shaped by selecting B cells that can efficiently perform productive signaling, stimulated by self-antigens in the bone marrow, such as DNA. In support of that idea, we previously found a V segment from VH10 family that can form antibodies that bind to DNA independent of CDR3 usage. In this paper we designed four antibody fragments in a novel single-chain pre-BCR (scpre-BCR) format containing germinal V gene segments from families known to bind DNA (VH10) or not (VH4) connected to a murine surrogate light chain (SLC), lacking the highly charged unique region (UR), by a hydrophilic peptide linker. We also tested the influence of CDR2 on DNA reactivity by shuffling the CDR2 loop. The scpre-BCRs were expressed in bacteria. VH10 bearing scpre-BCR could bind DNA, while scpre-BCR carrying the VH4 segment did not. The CDR2 loop shuffling hampered VH10 reactivity while displaying a gain-of-function in the nonbinding VH4 germline. We modeled the binding sites demonstrating the conservation of a positivity charged pocket in the VH10 CDR2 as the possible cross-reactive structural element. We presented evidence of DNA reactivity hardwired in a V gene, suggesting a structural mechanism for innate autoreactivity. Therefore, while autoreactivity to DNA can lead to autoimmunity, efficiently signaling for B cell development is likely a trade-off mechanism leading to the selection of potentially autoreactive repertoires.

Asunto(s)

Región Variable de Inmunoglobulina/genética , Anticuerpos de Dominio Único/genética , Anticuerpos de Dominio Único/inmunología , Secuencia de Aminoácidos/genética , Animales , Anticuerpos Antinucleares/genética , Arginina/genética , Arginina/metabolismo , Autoantígenos/genética , Autoinmunidad/inmunología , Secuencia de Bases/genética , ADN/inmunología , Células Germinativas/inmunología , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Pesadas de Inmunoglobulina/metabolismo , Región Variable de Inmunoglobulina/metabolismo , Región Variable de Inmunoglobulina/ultraestructura , Ratones , Anticuerpos de Dominio Único/ultraestructura , Relación Estructura-Actividad

RESUMEN

Anti-DNA antibodies are usually produced against histone-DNA complexes appearing during cell apoptosis, while histones are known as damage-associated molecules. A myelin sheath of axons contains myelin basic protein (MBP) playing an important role in the pathogenesis of autoimmune diseases. Antibodies with enzymatic activities (abzymes) are distinctive features of some autoimmune and viral diseases. Abzymes against different proteins can usually only hydrolyze these specific proteins. Using sequential chromatographies of homogeneous IgG preparations from sera of HIV-infected patients on columns with immobilized MBP, H2a, and H2b histones, the anti-MBP, anti-H2a, and anti-H2b antibodies were obtained. It was first shown that IgGs against H2a and H2b effectively hydrolyze these histones and MBP, while anti-MBP split MBP, H2a, and H2b, but no other control proteins. Using the MALDI mass spectrometry, the cleavage sites of H2a, H2b, and MBP by abzymes against these three proteins were found. Among 14 sites of hydrolysis of H2a by IgGs against H2a and 10 sites by anti-MBP IgGs, only one site of hydrolysis was the same for these abzymes. Eleven cleavage sites of H2b with IgGs against H2b and 10 sites of its hydrolysis with antibodies against MBP were different. Anti-H2a, anti-H2b, and anti-MBP abzymes are unpredictable examples of IgGs possessing not only cross-complexation but also catalytic cross-reactivity, which may be a common phenomenon for such abzymes in patients with different autoimmune diseases. The existence of cross-reactivity of abzymes against H2a and H2b histones and MBP represent a great danger to humans since, in contrast with MBP, histones due to cell apoptosis constantly occur in human blood. Anti-H2a, anti-H2b, and anti-MBP can attack and hydrolyze myelin basic protein of the myelin sheath of axons and plays a negative role in the pathogenesis of several pathologies.

Asunto(s)

Infecciones por VIH/inmunología , Histonas/inmunología , Complejos Multiproteicos/inmunología , Proteína Básica de Mielina/inmunología , Anticuerpos Antinucleares/sangre , Anticuerpos Antinucleares/genética , Anticuerpos Antinucleares/inmunología , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , VIH/patogenicidad , Infecciones por VIH/sangre , Infecciones por VIH/genética , Histonas/sangre , Humanos , Hidrólisis , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Complejos Multiproteicos/sangre , Proteína Básica de Mielina/sangre , Proteolisis , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción

RESUMEN

BACKGROUND: Systemic lupus erythematosus (SLE) is a severe autoimmune disease in which immune tolerance defects drive production of pathogenic anti-nuclear autoantibodies. Anergic B cells are considered a potential source of these autoantibodies due to their autoreactivity and overrepresentation in SLE patients. Studies of lupus-prone mice have shown that genetic defects mediating autoimmunity can breach B cell anergy, but how this breach occurs with regards to endogenous nuclear antigen remains unclear. We investigated whether B and T cell defects in congenic mice (c1) derived from the lupus-prone New Zealand Black strain can breach tolerance to nuclear self-antigen in the presence of knock-in genes (Vκ8/3H9; dKI) that generate a ssDNA-reactive, anergic B cell population. METHODS: Flow cytometry was used to assess splenic B and T cells from 8-month-old c1 dKI mice and serum autoantibodies were measured by ELISA. dKI B cells stimulated in vitro with anti-IgM were assessed for proliferation and activation by examining CFSE decay and CD86. Cytokine-producing T cells were identified by flow cytometry following culture of dKI splenocytes with PMA and ionomycin. dKI B cells from 6-8-week-old mice were adoptively transferred into 4-month-old wild type recipients and assessed after 7 days via flow cytometry and immunofluorescence microscopy. RESULTS: c1 dKI mice exhibited B cell proliferation indicative of impaired anergy, but had attenuated autoantibodies and germinal centres compared to wild type littermates. This attenuation appeared to stem from a decrease in PD-1hi T helper cells in the dKI strains, as c1 dKI B cells were recruited to germinal centres when adoptively transferred into c1 wild type mice. CONCLUSION: Anergic, DNA-specific autoreactive B cells only seem to drive profound autoimmunity in the presence of concomitant defects in the T cell subsets that support high-affinity plasma cell production.

Asunto(s)

Anticuerpos Antinucleares/genética , Anticuerpos Antifosfolípidos/genética , Antígenos/inmunología , Linfocitos B/inmunología , Anergia Clonal , Lupus Eritematoso Sistémico/inmunología , Animales , Linfocitos B/citología , Proliferación Celular , ADN de Cadena Simple/inmunología , Susceptibilidad a Enfermedades , Técnicas de Sustitución del Gen , Lupus Eritematoso Sistémico/genética , Ratones

RESUMEN

Phenotypic variation of quantitative traits is orchestrated by a complex interplay between the environment (e.g. diet) and genetics. However, the impact of gene-environment interactions on phenotypic traits mostly remains elusive. To address this, we feed 1154 mice of an autoimmunity-prone intercross line (AIL) three different diets. We find that diet substantially contributes to the variability of complex traits and unmasks additional genetic susceptibility quantitative trait loci (QTL). By performing whole-genome sequencing of the AIL founder strains, we resolve these QTLs to few or single candidate genes. To address whether diet can also modulate genetic predisposition towards a given trait, we set NZM2410/J mice on similar dietary regimens as AIL mice. Our data suggest that diet modifies genetic susceptibility to lupus and shifts intestinal bacterial and fungal community composition, which precedes clinical disease manifestation. Collectively, our study underlines the importance of including environmental factors in genetic association studies.

Asunto(s)

Cruzamientos Genéticos , Dieta , Genes , Estudios de Asociación Genética , Carácter Cuantitativo Heredable , Animales , Animales no Consanguíneos , Anticuerpos Antinucleares/genética , Bacterias/crecimiento & desarrollo , Biodiversidad , Femenino , Hongos/crecimiento & desarrollo , Predisposición Genética a la Enfermedad , Nefritis Lúpica/genética , Nefritis Lúpica/inmunología , Masculino , Ratones , Microbiota , Mapeo Físico de Cromosoma , Sitios de Carácter Cuantitativo/genética , Bazo/metabolismo , Transcriptoma/genética , Secuenciación Completa del Genoma

RESUMEN

Juvenile-onset systemic sclerosis (jSSc) is a rare and severe autoimmune disease with associated life-threatening organ inflammation and evidence of fibrosis. The organ manifestations of jSSc resemble adult SSc, but with better outcomes and survival. The etiology of jSSc appears to reflect adult-onset SSc, with similar inflammatory mediators and autoantibodies, but with a significant population of children with uncharacterized anti-nuclear antibodies. The genetics of patients with jSSc differ from women with SSc, resembling instead the genes of adult males with SSc, with additional HLA genes uniquely associated with childhood-onset disease. Current treatments are aimed at inhibiting the inflammatory aspect of disease, but important mechanisms of fibrosis regulated by dermal white adipose tissue dendritic cells may provide an avenue for targeting and potentially reversing the fibrotic stage.

Asunto(s)

Anticuerpos Antinucleares/inmunología , Células Dendríticas/inmunología , Dermis/inmunología , Esclerodermia Sistémica/inmunología , Grasa Subcutánea/inmunología , Adulto , Anticuerpos Antinucleares/genética , Niño , Células Dendríticas/patología , Dermis/patología , Femenino , Humanos , Esclerodermia Sistémica/genética , Esclerodermia Sistémica/patología , Grasa Subcutánea/patología

RESUMEN

Anti-nuclear antibodies to speckled 100 kDa (sp100) and glycoprotein 210 (gp210) are specific serologic markers of primary biliary cholangitis (PBC) of uncertain/controversial clinical or prognostic significance. To study the genetic determinants associated with sp100 and gp210 autoantibody subphenotypes, we performed a genome-wide association analysis of 930 PBC cases based on their autoantibody status, followed by a replication study in 1,252 PBC cases. We confirmed single-nucleotide polymorphisms rs492899 (P = 3.27 × 10-22 ; odds ratio [OR], 2.90; 95% confidence interval [CI], 2.34-3.66) and rs1794280 (P = 5.78 × 10-28 ; OR, 3.89; 95% CI, 3.05-4.96) in the human major histocompatibility complex (MHC) region associated with the sp100 autoantibody. However, no genetic variant was identified as being associated with the gp210 autoantibody. To further define specific classical human leukocyte antigen (HLA) alleles or amino acids associated with the sp100 autoantibody, we imputed 922 PBC cases (211 anti-sp100-positive versus 711 negative cases) using a Han Chinese MHC reference database. Conditional analysis identified that HLA-DRß1-Asn77/Arg74, DRß1-Ser37, and DPß1-Lys65 were major determinants for sp100 production. For the classical HLA alleles, the strongest association was with DRB1*03:01 (P = 1.51 × 10-9 ; OR, 2.97; 95% CI, 2.06-4.29). Regression analysis with classical HLA alleles identified DRB1*03:01, DRB1*15:01, DRB1*01, and DPB1*03:01 alleles can explain most of the HLA association with sp100 autoantibody. Conclusion: This study indicated significant genetic predisposition to the sp100 autoantibody, but not the gp210 autoantibody, subphenotype in PBC patients. Additional studies will be necessary to determine if these findings have clinical significance to PBC pathogenesis and/or therapeutics.

Asunto(s)

Anticuerpos Antinucleares/genética , Antígenos Nucleares/inmunología , Autoantígenos/inmunología , Cirrosis Hepática Biliar/genética , Anciano , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Cirrosis Hepática Biliar/inmunología , Masculino , Persona de Mediana Edad

RESUMEN

A Doença Mista do Tecido Conjuntivo (DMTC) é uma doença autoimune crônica composta por um misto de quatro doenças: Lúpus Eritematoso Sistêmico, Esclerose Sistêmica, Dermatomiosite/Polimiosite e Artrite Reumatoide. Por se tratar de uma combinação de doenças autoimunes o diagnóstico é bastante complexo. Atualmente existem quatro combinações sugeridas por diferentes autores para a realização de um diagnóstico preciso, são eles: Kasukawa, Alarcón-Segovia e Villareal, Kahn e Appeboom e Sharp. Desde a sua descoberta em 1972 por Sharp, passaram-se 46 anos e desta forma o objetivo desta revisão foi verificar a evolução do diagnóstico da DMTC desde a sua descoberta até a atualidade. Para isso utilizou-se sites de busca PUBMED e SCIELO. Por se tratar de uma doença autoimune que leva ao desenvolvimento de um quadro inflamatório crônico utilizou-se a ferramenta STRING que permite a análise da interação de proteínas. Até a presente data, não existe um consenso de qual critério deve ser usado para o diagnóstico correto e eficiente desta doença. A baixa relação de interações observadas a partir da ferramenta STRING demonstra que ainda não existem dados suficientes na literatura para que a ligação entre proteínas marcadoras e a DTMC possa ser estabelecida. (AU)

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Mixed connective tissue disease (MCTD) is a chronic autoimmune disorder consisting of a mixture of four diseases: systemic lupus erythematosus, systemic sclerosis, dermatomyositis/polymyositis, and rheumatoid arthritis. Because it is a combination of different autoimmune disorders its diagnosis is quite complex. Currently there are four combinations suggested by the following authors to establish an accurate diagnosis: Kasukawa, Alarcón-Segovia & Villareal, Kahn, and Appeboom & Sharp. It has been 46 years since Sharp reported the disease in 1972 and thus the purpose of this review was to investigate the evolution of the diagnosis of MCTD since then. PubMed and SciELO databases were used for this investigation. Because MCTD is an autoimmune disease that leads to the development of a chronic inflammatory condition, the STRING tool was used to allow the analysis of protein interaction. To date, there is no consensus as to what criterion should be used for a correct and efficient diagnosis of this disease. The low ratio of interactions observed from the STRING tool demonstrates that there is not yet enough data in the literature for establishing the binding between marker proteins and MCTD. (AU)

Asunto(s)

Humanos , Masculino , Femenino , Enfermedad Mixta del Tejido Conjuntivo/diagnóstico , Enfermedad Mixta del Tejido Conjuntivo/genética , Anticuerpos Antinucleares/genética , Anticuerpos Antinucleares/sangre , Biología Computacional/métodos

RESUMEN

BACKGROUND MAD2 is the gene controlling mitosis. Many studies have assessed MAD2 in various types of carcinoma. Antinuclear mitotic spindle apparatus antibody (MSA) and anticentromere antibody (ACA) are related mitotic antibodies, playing roles in autoimmune diseases and carcinomas, but the expression of MAD2, MSA, and ACA in SCLC is unclear. MATERIAL AND METHODS We enrolled 70 SCLC patients, 72 non-small cell lung cancer (NSCLC) patients, and 65 pulmonary nodule (PN) patients. MAD2 expression was measured through agarose electrophoresis and qt-PCR. Antinuclear mitotic spindle apparatus antibody (MSA) and anticentromere antibody (ACA) were detected by indirect immunofluorescence (IIF). RESULTS MAD2 was found both in SCLC and NSCLC. Interestingly, there was a significant difference found between SCLC and NSCLC using qt-PCR (P<0.05). The area under the ROC curve of MAD2 expression was 0.799, with medium diagnostic value. MAD2 expression was related to age, lymphatic metastasis, and survival time, but not with sex. The positivity for MSA and ACA by IIF assay were 37.20% and 34.00%, respectively, in the SCLC group, which were higher than in the NSCLC and pulmonary nodule groups (P<0.05). The kappa values of MSA and ACA with MAD2 expression were 0.73 and 0.65, respectively, with moderate consistency. Combining MAD2 with MSA and ACA enhanced the sensitivity and specificity for diagnosing SCLC. CONCLUSIONS MAD2 expression was found to be involved in carcinogenesis and prognosis of SCLC. The combination of MAD2 with MSA and ACA is useful for early diagnosis and shows promise in treatment of SCLC.

Asunto(s)

Anticuerpos Antinucleares/biosíntesis , Biomarcadores de Tumor/biosíntesis , Neoplasias Pulmonares/metabolismo , Proteínas Mad2/biosíntesis , Carcinoma Pulmonar de Células Pequeñas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antinucleares/genética , Biomarcadores de Tumor/genética , Femenino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Metástasis Linfática , Proteínas Mad2/genética , Masculino , Persona de Mediana Edad , Pronóstico , Carcinoma Pulmonar de Células Pequeñas/genética , Carcinoma Pulmonar de Células Pequeñas/patología , Huso Acromático/inmunología , Análisis de Supervivencia , Transcriptoma

RESUMEN

Anti-DNA autoantibodies are a hallmark of systemic lupus erythematosus (SLE). A subset of anti-DNA IgG autoantibodies is cell-internalizable; thus they can enter living cells in the form of free IgG. However, the contribution made by the Fc region of internalized free-form IgG to the cytokine response has not been studied, despite the recent discovery of tripartite motif-containing 21 (TRIM21), a cytosolic Fc receptor involved in immune signaling. This study used an internalizable IgG anti-DNA antibody (3D8) to examine the cytokine responses of human monocytes to the Fc region of cytosolic free IgG. Internalization of 3D8 IgG and a 3D8 single-chain variable fragment-Fc (scFv-Fc) induced production of IL-8 and TNF-α via activation of NF-κB. By contrast, a 3D8 scFv (comprising variable domains alone) did not. This suggests Fc-dependent cytokine signaling. A 3D8 IgG-N434D mutant that is not recognized by TRIM21 induced greater production of cytokines than 3D8 IgG. Moreover the amounts of cytokines induced by 3D8 IgG in TRIM21-knockdown THP-1 cells were higher than those in control cells, indicating that cytokine signaling is not mediated by TRIM21. The results suggest the existence of a novel Fc-dependent signaling pathway that is activated upon internalization of IgG antibodies by human monocytes.

Asunto(s)

Anticuerpos Antinucleares/metabolismo , Inmunoglobulina G/metabolismo , Lupus Eritematoso Sistémico/inmunología , Monocitos/fisiología , Ribonucleoproteínas/metabolismo , Anticuerpos Antinucleares/genética , Citosol/metabolismo , Endocitosis , Humanos , Inmunoglobulina G/genética , Mediadores de Inflamación/metabolismo , Interleucina-8/metabolismo , Mutación/genética , FN-kappa B/metabolismo , ARN Interferente Pequeño/genética , Receptores Fc/metabolismo , Ribonucleoproteínas/genética , Transducción de Señal , Anticuerpos de Cadena Única/genética , Células THP-1 , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

Anti-double-stranded (ds)DNA autoantibodies are prototypical serological markers of systemic lupus erythematosus (SLE), but little is known about their immunoglobulin variable (IgV) region composition at the level of the secreted (serum) proteome. Here, we use a novel proteomic workflow based on de novo mass spectrometric sequencing of anti-dsDNA precipitins to analyse IgV subfamily expression and mutational signatures of high-affinity, precipitating anti-dsDNA responses. Serum anti-dsDNA proteomes were oligoclonal with shared (public) expression of immunoglobulin (Ig)G heavy chain variable region (IGHV) and kappa chain variable region (IGKV) subfamilies. IgV peptide maps from eight subjects showed extensive public and random (private) amino acid replacement mutations with prominent arginine substitutions across heavy (H)- and light (L)-chains. Shared sets of L-chain complementarity determining region 3 (CDR3) peptides specified by arginine substitutions were sequenced from the dominantly expressed IGKV3-20 subfamily, with changes in expression levels of a clonal L-chain CDR3 peptide by quantitative multiple reaction monitoring (MRM) paralleling the rise and fall of anti-dsDNA levels by Farr radioimmunoassays (RIA). The heavily mutated IgV peptide signatures of precipitating anti-dsDNA autoantibody proteomes reflect the strong selective forces that shape humoral anti-dsDNA responses in germinal centres. Direct sequencing of agarose gel precipitins using microlitre volumes of stored sera streamlines the antibody sequencing workflow and is generalizable to other precipitating serum antibodies.

Asunto(s)

Anticuerpos Antinucleares/genética , Regiones Determinantes de Complementariedad/genética , Región Variable de Inmunoglobulina/genética , Cadenas kappa de Inmunoglobulina/genética , Lupus Eritematoso Sistémico/inmunología , Adulto , Anciano de 80 o más Años , Secuencia de Aminoácidos , Sustitución de Aminoácidos/genética , Anticuerpos Antinucleares/sangre , Anticuerpos Antinucleares/inmunología , ADN/inmunología , Femenino , Humanos , Inmunoglobulina G/genética , Inmunoglobulina G/inmunología , Región Variable de Inmunoglobulina/inmunología , Cadenas kappa de Inmunoglobulina/inmunología , Masculino , Espectrometría de Masas , Persona de Mediana Edad , Adulto Joven

RESUMEN

N6-Methyladenosine (m6A) is an abundant post-transcriptional RNA modification that influences multiple aspects of gene expression. In addition to recruiting proteins, m6A can modulate RNA function by destabilizing base pairing. Here, we show that when neighbored by a 5' bulge, m6A stabilizes m6A-U base pairs, and global RNA structure by ~1 kcal mol-1. The bulge most likely provides the flexibility needed to allow optimal stacking between the methyl group and 3' neighbor through a conformation that is stabilized by Mg2+. A bias toward this motif can help explain the global impact of methylation on RNA structure in transcriptome-wide studies. While m6A embedded in duplex RNA is poorly recognized by the YTH domain reader protein and m6A antibodies, both readily recognize m6A in this newly identified motif. The results uncover potentially abundant and functional m6A motifs that can modulate the epitranscriptomic structure landscape with important implications for the interpretation of transcriptome-wide data.

Asunto(s)

Adenosina/análogos & derivados , Magnesio/metabolismo , Procesamiento Postranscripcional del ARN , ARN Mensajero/metabolismo , Transcriptoma , Adenosina/metabolismo , Anticuerpos Antinucleares/genética , Anticuerpos Antinucleares/metabolismo , Emparejamiento Base , Sitios de Unión , Cationes Bivalentes , Clonación Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Conformación de Ácido Nucleico , Motivos de Nucleótidos , Unión Proteica , Estabilidad del ARN , ARN Mensajero/química , ARN Mensajero/genética , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Termodinámica

RESUMEN

A key challenge in the development of novel chemotherapeutics is the design of molecules capable of selective toxicity to cancer cells. Antibodies have greater target specificity compared to small molecule drugs, but most are unable to penetrate cells, and predominantly target extracellular antigens. A nuclear-penetrating anti-DNA autoantibody isolated from the MRL/lpr lupus mouse model, 3E10, preferentially localizes to tumors, inhibits DNA repair, and selectively kills cancer cells with defects in DNA repair. A murine divalent single chain variable fragment of 3E10 with mutations for improved DNA binding affinity, 3E10 (D31N) di-scFv, has previously been produced in P. pastoris and yielded promising pre-clinical findings, but is unsuitable for clinical testing. The present study reports the design, expression and testing of a panel of humanized 3E10 (D31N) di-scFvs, some of which contain CDR substitution. These variants were expressed in a modified CHO system and evaluated for their physicochemical attributes and ability to penetrate nuclei to selectively cause DNA damage accumulation in and kill cancer cells with DNA repair defects. Secondary structure was conserved and most variants retained the key characteristics of the murine 3E10 (D31N) di-scFv produced in P. pastoris. Moreover, several variants with CDR substitutions outperformed the murine prototype. In conclusion, we have designed several humanized variants of 3E10 (D31N) di-scFv that have potential for application as monotherapy or conjugates for targeted nuclear drug delivery.

Asunto(s)

Anticuerpos Antinucleares/genética , Anticuerpos Antinucleares/inmunología , Autoanticuerpos/genética , Autoanticuerpos/inmunología , ADN/genética , ADN/inmunología , Ingeniería de Proteínas/métodos , Animales , Anticuerpos Antinucleares/uso terapéutico , Autoanticuerpos/uso terapéutico , Daño del ADN/inmunología , Ratones

RESUMEN

The signature lesion of SSA/Ro autoantibody-associated congenital heart block (CHB) is fibrosis and a macrophage infiltrate, supporting an experimental focus on cues influencing the fibroblast component. The transcriptomes of human fetal cardiac fibroblasts were analyzed using two complementary approaches. Cardiac injury conditions were simulated in vitro by incubating human fetal cardiac fibroblasts with supernatants from macrophages transfected with the SSA/Ro-associated noncoding Y ssRNA. The top 10 upregulated transcripts in the stimulated fibroblasts reflected a type I interferon (IFN) response [e.g., IFN-induced protein 44-like (IFI44L), of MX dynamin-like GTPase (MX)1, MX2, and radical S-adenosyl methionine domain containing 2 (Rsad2)]. Within the fibrotic pathway, transcript levels of endothelin-1 (EDN1), phosphodiesterase (PDE)4D, chemokine (C-X-C motif) ligand (CXCL)2, and CXCL3 were upregulated, while others, including adenomedullin, RAP guanine nucleotide exchange factor 3 (RAPGEF3), tissue inhibitor of metalloproteinase (TIMP)1, TIMP3, and dual specificity phosphatase 1, were downregulated. Agnostic Database for Annotation, Visualization and Integrated Discovery analysis revealed a significant increase in inflammatory genes, including complement C3A receptor 1 (C3AR1), F2R-like thrombin/trypsin receptor 3, and neutrophil cytosolic factor 2. In addition, stimulated fibroblasts expressed high levels of phospho-MADS box transcription enhancer factor 2 [a substrate of MAPK5 (ERK5)], which was inhibited by BIX-02189, a specific inhibitor of ERK5. Translation to human disease leveraged an unprecedented opportunity to interrogate the transcriptome of fibroblasts freshly isolated and cell sorted without stimulation from a fetal heart with CHB and a matched healthy heart. Consistent with the in vitro data, five IFN response genes were among the top 10 most highly expressed transcripts in CHB fibroblasts. In addition, the expression of matrix-related genes reflected fibrosis. These data support the novel finding that cardiac injury in CHB may occur secondary to abnormal remodeling due in part to upregulation of type 1 IFN response genes.NEW & NOTEWORTHY Congenital heart block is a rare disease of the fetal heart associated with maternal anti-Ro autoantibodies which can result in death and for survivors, lifelong pacing. This study provides in vivo and in vitro transcriptome-support that injury may be mediated by an effect of Type I Interferon on fetal fibroblasts.

Asunto(s)

Anticuerpos Antinucleares/metabolismo , Corazón Fetal/metabolismo , Fibroblastos/metabolismo , Perfilación de la Expresión Génica , Bloqueo Cardíaco/congénito , Mediadores de Inflamación/metabolismo , Interferón Tipo I/metabolismo , Transcriptoma , Adulto , Anticuerpos Antinucleares/genética , Anticuerpos Antinucleares/inmunología , Células Cultivadas , Medios de Cultivo Condicionados/metabolismo , Femenino , Corazón Fetal/inmunología , Corazón Fetal/patología , Fibroblastos/patología , Fibrosis , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica , Bloqueo Cardíaco/genética , Bloqueo Cardíaco/inmunología , Bloqueo Cardíaco/metabolismo , Bloqueo Cardíaco/patología , Humanos , Mediadores de Inflamación/inmunología , Factores Reguladores del Interferón/genética , Factores Reguladores del Interferón/metabolismo , Interferón Tipo I/inmunología , Macrófagos/inmunología , Macrófagos/metabolismo , Miocardio , Comunicación Paracrina , Embarazo , Transfección

RESUMEN

Targeting and modification of important intracellular proteins using efficient vehicles are invaluable in diagnostic and therapeutic fields. Cell-penetrating antibodies and their fragments can be utilized as vehicles for the delivery of modifiers into cells. In this study, we explored the applicability of variable heavy chain (VH) domain as delivery vehicles for mammalian cells. The characteristics of the recombinant VH domain produced from a cell-penetrating monoclonal anti-double stranded DNA antibody 2C10 were analyzed using flow cytometry, confocal microscopy, cell proliferation assay, and cell cycle analysis in various mammalian cell lines. The VH domain penetrated into various cell lines in a time- and dose-dependent manner, although the internalization efficiency varied. The domain was localized in the nuclei as well as the cytoplasm of living cells. It was also internalized into cells mainly through the clathrin-mediated endocytosis pathway. We tested further its efficiency in delivering specific biomolecule(s) using the conjugates of the single domain molecule and small interfering RNA (siRNA) for the testicular nuclear auto-antigenic sperm protein (tNASP). It was found that the siRNA was successfully delivered by the VH domain into cancer cells, and knockdown effects from the delivered tNASP-siRNA were observed. The levels of the RNA transcript and protein of tNASP were decreased and the down-regulated tNASP inhibited cell proliferation and caused G0G1 phase arrest of the cell cycle. These results indicate that the recombinant 2C10 VH domain could be applied as an efficient vehicle capable of delivering valuable biomolecule into the cytoplasm or cell nuclei for clinical uses.

Asunto(s)

Anticuerpos Antinucleares/genética , Péptidos de Penetración Celular/genética , Sistemas de Liberación de Medicamentos/métodos , Inmunoconjugados/genética , ARN Interferente Pequeño/genética , Anticuerpos de Dominio Único/genética , Animales , Anticuerpos Antinucleares/química , Anticuerpos Antinucleares/metabolismo , Autoantígenos/genética , Autoantígenos/metabolismo , Células COS , Puntos de Control del Ciclo Celular/genética , Proliferación Celular , Péptidos de Penetración Celular/química , Péptidos de Penetración Celular/metabolismo , Chlorocebus aethiops , Endocitosis , Expresión Génica , Técnicas de Silenciamiento del Gen , Células HCT116 , Células HeLa , Humanos , Inmunoconjugados/química , Inmunoconjugados/metabolismo , Células Jurkat , Ratones , Células 3T3 NIH , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , ARN Interferente Pequeño/química , ARN Interferente Pequeño/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Anticuerpos de Dominio Único/química , Anticuerpos de Dominio Único/metabolismo

RESUMEN

Background Estrogens have a modulatory effect on several immune responses, many of which are correlated to autoimmune diseases. Estrogens act through binding to their receptors, and an overexpression of these receptors has been identified in patients with different autoimmune diseases. Here we analyzed the association of a putative functional genetic variant in the main estrogen receptor (ERα) gene ( ESR1), and the susceptibility to clinical findings and severity of SLE. Methods A total of 426 individuals (266 healthy controls and 160 SLE patients) were genotyped for the polymorphism rs2234693 in the ESR1 gene. Allele and genotype frequencies were calculated and analyzed between cases and controls using Unphased software. Results The SNP rs2234693 was not associated with SLE per se but the minor allele rs2234693-C was correlated with the presence of nephritis and discoid skin rash. On the other hand, the rs2234693-CC genotype was correlated with the absence of arthritis as well as anti-ANA and anti-RNP autoantibodies. The comprehensive clinical analysis of these patients revealed a more severe status of the disease, characterized by a younger age of onset and higher number of organs involved when compared to European populations. Conclusions Minor allele rs2234693-C was associated with renal and cutaneous involvement, as well as the absence of arthritis, anti-ANA and anti-RNP autoantibodies.

Asunto(s)

Receptor alfa de Estrógeno/genética , Lupus Eritematoso Sistémico/genética , Adulto , Alelos , Anticuerpos Antinucleares/genética , Artritis/genética , Brasil , Estudios de Casos y Controles , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lupus Eritematoso Sistémico/inmunología , Masculino , Polimorfismo de Nucleótido Simple , Adulto Joven

RESUMEN

IgG anti-DNA antibodies are both diagnostic and pathogenic for systemic lupus erythematosus (SLE). They contribute to tissue inflammation through direct tissue binding and to systemic inflammation through activation of Toll-like receptors by nucleic acid-containing immune complexes. IgG DNA-reactive antibodies originate when B cell tolerance mechanisms are impaired. The heterogeneous immune perturbations in SLE lead to the survival and activation of DNA-reactive B cells in various B cell subsets at distinct stages of B cell maturation and differentiation. We propose that the spectrum of B cell alterations and failed tolerance mechanisms for DNA-reactive B cells in lupus patients is best understood by studying genetic risk alleles. This implies that the B cells producing IgG anti-DNA antibodies and the failed tolerance mechanisms(s) will differ across patients. A better understanding of these differences should lead to better patient stratification, improved outcomes of clinical trials, and the identification of novel therapeutic targets.

Asunto(s)

Anticuerpos Antinucleares/metabolismo , Subgrupos de Linfocitos B/inmunología , Linfocitos B/inmunología , ADN/inmunología , Lupus Eritematoso Sistémico/inmunología , Alelos , Animales , Anticuerpos Antinucleares/genética , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Tolerancia Inmunológica , Lupus Eritematoso Sistémico/genética , Riesgo