RESUMO
Cognitive impairment is a frequent manifestation of neuropsychiatric systemic lupus erythematosus, present in up to 80% of patients and leading to a diminished quality of life. In the present study, we used a model of lupus-like cognitive impairment that is initiated when antibodies that crossreact with excitatory neuronal receptors penetrate the hippocampus, causing immediate, self-limited, excitotoxic death of hippocampal neurons, which is then followed by a significant loss of dendritic complexity in surviving neurons. This injury creates a maladaptive equilibrium that is sustained in mice for at least 1 year. We identified a feedforward loop of microglial activation and microglia-dependent synapse elimination dependent on neuronal secretion of high mobility group box 1 protein (HMGB1) which binds the receptor for advanced glycation end products (RAGE) and leads to microglial secretion of C1q, upregulation of interleukin-10 with consequent downregulation of leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1), an inhibitory receptor for C1q. Treatment with a centrally acting angiotensin-converting enzyme inhibitor or with an angiotensin-receptor blocker restored a healthy equilibrium, microglial quiescence and intact spatial memory.
Assuntos
Autoanticorpos , Proteína HMGB1 , Animais , Camundongos , Complemento C1q , Proteína HMGB1/metabolismo , Doenças Neuroinflamatórias , Qualidade de Vida , Receptor para Produtos Finais de Glicação Avançada/metabolismoRESUMO
The brain is normally sequestered from antibody exposure by the blood brain barrier. However, antibodies can access the brain during fetal development before the barrier achieves full integrity, and in disease states when barrier integrity is compromised. Recent studies suggest that antibodies contribute to brain pathology associated with autoimmune diseases such as systemic lupus erythematosus and neuromyelitis optica, and can lead to transient or permanent behavioral or cognitive abnormalities. We review these findings here and examine the circumstances associated with antibody entry into the brain, the routes of access and the mechanisms that then effect pathology. Understanding these processes and the nature and specificity of neuronal autoantibodies may reveal therapeutic strategies toward alleviating or preventing the neurological pathologies and behavioral abnormalities associated with autoimmune disease.
Assuntos
Anticorpos/imunologia , Encéfalo/imunologia , Encéfalo/patologia , Animais , HumanosRESUMO
Damaging interactions between antibodies and brain antigenic targets may be responsible for an expanding range of neurological disorders. In the case of systemic lupus erythematosus (SLE), patients generate autoantibodies (AAbs) that frequently bind dsDNA. Although some symptoms of SLE may arise from direct reactivity to dsDNA, much of the AAb-mediated damage originates from cross-reactivity with other antigens. We have studied lupus AAbs that bind dsDNA and cross-react with the NR2A and NR2B subunits of the NMDA receptor (NMDAR). In adult mouse models, when the blood-brain barrier is compromised, these NMDAR-reactive AAbs access the brain and elicit neuronal death with ensuing cognitive dysfunction and emotional disturbance. The cellular mechanisms that underlie these deleterious effects remain incompletely understood. Here, we show that, at low concentration, the NMDAR-reactive AAbs are positive modulators of receptor function that increase the size of NMDAR-mediated excitatory postsynaptic potentials, whereas at high concentration, the AAbs promote excitotoxicity through enhanced mitochondrial permeability transition. Other synaptic receptors are completely unaffected by the AAbs. NMDAR activation is required for producing both the synaptic and the mitochondrial effects. Our study thus reveals the mechanisms by which NMDAR-reactive AAbs trigger graded cellular alterations, which are likely to be responsible for the transient and permanent neuropsychiatric symptoms observed in patients with SLE. Our study also provides a model in which local AAb concentration determines the exact nature of the cellular response.
Assuntos
Autoanticorpos/toxicidade , Encéfalo/imunologia , Encéfalo/fisiopatologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Vasculite Associada ao Lúpus do Sistema Nervoso Central/imunologia , Vasculite Associada ao Lúpus do Sistema Nervoso Central/fisiopatologia , Neurotoxinas/toxicidade , Animais , Reações Cruzadas , Potenciais Pós-Sinápticos Excitadores , Feminino , Humanos , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Transporte da Membrana Mitocondrial/fisiologia , Poro de Transição de Permeabilidade Mitocondrial , Modelos Imunológicos , Modelos Neurológicos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/imunologiaRESUMO
Cognitive impairment is a frequent manifestation of neuropsychiatric systemic lupus erythematosus (NPSLE), present in up to 80% of patients and leading to a diminished quality of life. We have developed a model of lupus-like cognitive impairment which is initiated when anti-DNA, anti-N-methyl D-aspartate receptor (NMDAR) cross- reactive antibodies, which are present in 30% of SLE patients, penetrate the hippocampus1. This leads to immediate, self-limited excitotoxic death of CA1 pyramidal neurons followed by a significant loss of dendritic arborization in the remaining CA1 neurons and impaired spatial memory. Both microglia and C1q are required for dendritic loss1. Here we show that this pattern of hippocampal injury creates a maladaptive equilibrium that is sustained for at least one year. It requires HMGB1 secretion by neurons to bind RAGE, a receptor for HMGB1 expressed on microglia, and leads to decreased expression of microglial LAIR-1, an inhibitory receptor for C1q. The angiotensin converting enzyme (ACE) inhibitor captopril, which can restore a healthy equilibrium, microglial quiescence, and intact spatial memory, leads to upregulation of LAIR-1. This paradigm highlights HMGB1:RAGE and C1q:LAIR-1 interactions as pivotal pathways in the microglial-neuronal interplay that defines a physiologic versus a maladaptive equilibrium.
RESUMO
Patients with Systemic lupus erythematosus (SLE) experience various peripheral and central nervous system manifestations including spatial memory impairment. A subset of autoantibodies (DNRAbs) cross-react with the GluN2A and GluN2B subunits of the NMDA receptor (NMDAR). We find that these DNRAbs act as positive allosteric modulators on NMDARs with GluN2A-containing NMDARs, even those containing a single GluN2A subunit, exhibiting a much greater sensitivity to DNRAbs than those with exclusively GluN2B. Accordingly, GluN2A-specific antagonists provide greater protection from DNRAb-mediated neuronal cell death than GluN2B antagonists. Using transgenic mice to perturb expression of either GluN2A or GluN2B in vivo, we find that DNRAb-mediated disruption of spatial memory characterized by early neuronal cell death and subsequent microglia-dependent pathologies requires GluN2A-containing NMDARs. Our results indicate that GluN2A-specific antagonists or negative allosteric modulators are strong candidates to treat SLE patients with nervous system dysfunction.
Assuntos
Autoanticorpos/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/psicologia , Receptores de N-Metil-D-Aspartato/imunologia , Memória Espacial , Animais , Morte Celular , Feminino , Humanos , Lúpus Eritematoso Sistêmico/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/citologia , Neurônios/imunologia , Receptores de N-Metil-D-Aspartato/genéticaRESUMO
Acetylation of lysines at different sites in the N-terminus of core histones is a common mode of chromatin modification; different combinations of such modifications are associated with distinct patterns of gene expression, replication and repair. Antibodies are usually used to identify and localize particular histone modifications and to correlate their presence with transcription or other cellular processes. This requires antibodies of sufficient specificity and affinity for each of the many modifications that have now been observed. In most instances, polyclonal antibodies have been used but monoclonal antibodies can also be effective. Here we report that a phage-displayed repertoire of rearranged antibody genes from splenic B cells from a patient with systemic lupus contain Fab fragments that can bind native acetylated lysine 8 histone H4. This finding represents the first selection of human antibodies specific for acetylated histone and suggests that lupus antibodies may contribute to dissection of the histone code.
Assuntos
Anticorpos Monoclonais/metabolismo , Autoanticorpos/metabolismo , Histona Acetiltransferases/metabolismo , Histonas/imunologia , Fragmentos Fab das Imunoglobulinas/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Acetilação , Anticorpos Monoclonais/genética , Afinidade de Anticorpos , Especificidade de Anticorpos , Autoanticorpos/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Biblioteca Gênica , Histonas/isolamento & purificação , Histonas/metabolismo , Humanos , Fragmentos Fab das Imunoglobulinas/genética , Região Variável de Imunoglobulina/metabolismo , Lúpus Eritematoso Sistêmico/genética , Proteínas Recombinantes/metabolismoRESUMO
Classic immunologic teaching describes the brain as an immunologically privileged site. Studies of neuroimmunology have focused for many years almost exclusively on multiple sclerosis, a disease in which inflammatory cells actually infiltrate brain tissue, and the rodent model of this disease, experimental allergic encephalitis. Over the past decade, however, increasingly, brain-reactive antibodies have been demonstrated in the serum of patients with numerous neurological diseases. The contribution these antibodies make to neuronal dysfunction has, in general, not been determined. Here, we describe recent studies showing that serum antibodies to the N-methyl-D-aspartate receptor occur frequently in patients with systemic lupus erythematosus and can cause alterations in cognition and behavior following a breach in the blood-brain barrier.
Assuntos
Transtornos Cognitivos/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/psicologia , Animais , Autoanticorpos/biossíntese , Autoanticorpos/fisiologia , Transtornos Cognitivos/metabolismo , Transtornos Cognitivos/psicologia , Modelos Animais de Doenças , Humanos , Lúpus Eritematoso Sistêmico/metabolismoRESUMO
A primary mechanism for activation of innate immunity is recognition of damage or pathogen associated molecular patterns by pattern recognition receptors (PRRs). Nucleic acid is a damage associated molecular pattern molecule that when internalized into a monocyte and recognized by intracellular nucleic acid sensing toll like receptors will cause production of type 1 interferon. The process by which DNA or RNA is delivered into the cytosol of monocytes in systemic lupus erythematosus remains incompletely understood, and therapeutic approaches to prevent DNA-mediated monocyte activation are needed. We identified two mechanisms for internalization of DNA by monocytes. IgG-bound DNA was internalized by interacting with Fc gamma receptor IIa, while high-mobility group box-1 protein-bound DNA was internalized by interacting with the receptor for advanced glycation end products. Both pathways contribute to an inflammatory phenotype in monocytes exposed to serum from patients with SLE. Moreover, both of these pathways can be inhibited by a pentapeptide, DWEYS, which is a DNA mimetope. In one instance DWEYS directly competes with DNA for antibody binding and in the other DWEYS binds high-mobility group box-1 and blocks its interaction with RAGE. Our data highlight distinct pathways involved in nucleic acid enters monocytes in SLE, and identify a potential therapeutic to prevent nucleic acid internalization in SLE.
Assuntos
Anticorpos Antinucleares , Ácidos Nucleicos Livres , Imunoglobulina G , Interferons , Lúpus Eritematoso Sistêmico , Monócitos , Animais , Anticorpos Antinucleares/sangue , Anticorpos Antinucleares/imunologia , Ácidos Nucleicos Livres/sangue , Ácidos Nucleicos Livres/imunologia , Feminino , Proteína HMGB1/sangue , Proteína HMGB1/imunologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Interferons/sangue , Interferons/imunologia , Lúpus Eritematoso Sistêmico/sangue , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Masculino , Camundongos Mutantes , Monócitos/imunologia , Monócitos/metabolismo , Monócitos/patologia , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , ômega-CloroacetofenonaRESUMO
Cognitive impairment occurs in 40-90% of patients with systemic lupus erythematosus (SLE), which is characterized by autoantibodies to nuclear antigens, especially DNA. We discovered that a subset of anti-DNA antibodies, termed DNRAbs, cross reacts with the N-methyl-d-aspartate receptor (NMDAR) and enhances NMDAR signaling. In patients, DNRAb presence associates with spatial memory impairment. In a mouse model, DNRAb-mediated brain pathology proceeds through an acute phase of excitotoxic neuron loss, followed by persistent alteration in neuronal integrity and spatial memory impairment. The latter pathology becomes evident only after DNRAbs are no longer detectable in the brain. Here we investigate the mechanism of long-term neuronal dysfunction mediated by transient exposure to antibody. We show that activated microglia and C1q are critical mediators of neuronal damage. We further show that centrally acting inhibitors of angiotensin-converting enzyme (ACE) can prevent microglial activation and preserve neuronal function and cognitive performance. Thus, ACE inhibition represents a strong candidate for clinical trials aimed at mitigating cognitive dysfunction.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Anticorpos Antinucleares/imunologia , Autoanticorpos , Encéfalo , Lúpus Eritematoso Sistêmico/imunologia , Transtornos da Memória , Neurônios/imunologia , Animais , Autoanticorpos/imunologia , Autoanticorpos/toxicidade , Encéfalo/imunologia , Encéfalo/patologia , Feminino , Lúpus Eritematoso Sistêmico/patologia , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/imunologia , Transtornos da Memória/patologia , Camundongos , Camundongos Endogâmicos BALB C , Microglia , Neurônios/patologia , Receptores de N-Metil-D-Aspartato/imunologiaRESUMO
The potential role of systemic inflammation on brain injury in newborns with congenital heart disease (CHD) was assessed by measuring levels of central nervous system (CNS)-derived proteins in serum prior to and following cardiac surgery. A total of 23 newborns (gestational age, 39±1 weeks) with a diagnosis of CHD that required cardiac surgery with cardiopulmonary bypass (CPB) were enrolled in the current study. Serum samples were collected immediately prior to surgery and 2, 24 and 48 h following CPB, and serum levels of phosphorylated neurofilament-heavy subunit (pNF-H), neuron-specific enolase (NSE) and S100B were analyzed. Systemic inflammation was assessed by measuring serum concentrations of complement C5a and complement sC5b9, and the following cytokines: Interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL12p70, interferon γ and tumor necrosis factor (TNF)-α. Analysis of cord blood from normal term deliveries (n=26) provided surrogate normative values for newborns. pNF-H and S100B were 2.4- to 2.8-fold higher (P<0.0001) in patient sera than in cord blood prior to surgery and remained elevated following CPB. Pre-surgical serum pNF-H and S100B levels directly correlated with interleukin (IL)-12p70 (ρ=0.442, P<0.05). pNF-H was inversely correlated with arterial pO2 prior to surgery (ρ=-0.493, P=0.01) and directly correlated with arterial pCO2 post-CPB (ρ=0.426, P<0.05), suggesting that tissue hypoxia and inflammation contribute to blood brain barrier (BBB) dysfunction and neuronal injury. Serum IL12p70, IL-6, IL-8, IL-10 and TNF-α levels were significantly higher in patients than in normal cord blood and levels of these cytokines increased following CPB (P<0.001). Activation of complement was observed in all patients prior to surgery, and serum C5a and sC5b9 remained elevated up to 48 h post-surgery. Furthermore, they were correlated (P<0.05) with low arterial pO2, high pCO2 and elevated arterial pressure in the postoperative period. Length of mechanical ventilation was associated directly with post-surgery serum IL-12p70 and IL-8 concentrations (P<0.05). Elevated serum concentrations of pNF-H and S100B in neonates with CHD suggest BBB dysfunction and CNS injury, with concurrent hypoxemia and an activated inflammatory response potentiating this effect.
RESUMO
Cells and molecules of the immune system contribute to brain pathology as well as to brain homeostasis. We suggest that there are numerous anti-brain antibodies that can cause acute neuronal dysfunction if they penetrate brain parenchyma. Many of these acute immune-mediated insults may alter the homeostatic mechanisms in the brain and initiate pathologic events that no longer depend on the presence of the inciting antibody, but rather on microglial cell activation. This paradigm, if correct, suggests that there may be two potential moments of therapeutic intervention. The first moment is when antibody contacts cells of the central nervous system and the second is when microglia become activated and impair normal neuronal functions. In this review, we discuss data that support this model for immune-mediated pathology in both the adult brain and the developing fetal brain.
Assuntos
Autoanticorpos/imunologia , Doenças Autoimunes do Sistema Nervoso/imunologia , Encefalopatias/imunologia , Encéfalo/imunologia , Microglia/imunologia , Doenças Autoimunes do Sistema Nervoso/patologia , Encéfalo/patologia , Encefalopatias/patologia , Humanos , Microglia/patologiaRESUMO
Systemic lupus erythematosus is an autoimmune disease that can affect numerous tissues and is characterized by the production of nuclear antigen-directed autoantibodies (e.g., anti-dsDNA). Using a combination of virtual and ELISA-based screens, we made the intriguing discovery that several HIV-protease inhibitors can function as decoy antigens to specifically inhibit the binding of anti-dsDNA antibodies to target antigens such as dsDNA and pentapeptide DWEYS. Computational modeling revealed that HIV-protease inhibitors comprised structural features present in DWEYS and predicted that analogues containing more flexible backbones would possess preferred binding characteristics. To address this, we reduced the internal amide backbone to improve flexibility, producing new small-molecule decoy antigens, which neutralize anti-dsDNA antibodies in vitro, in situ, and in vivo. Pharmacokinetic and SLE model studies demonstrated that peptidomimetic FISLE-412,1 a reduced HIV protease inhibitor analogue, was well-tolerated, altered serum reactivity to DWEYS, reduced glomeruli IgG deposition, preserved kidney histology, and delayed SLE onset in NZB/W F1 mice.
Assuntos
Anticorpos Antinucleares/imunologia , Inibidores da Protease de HIV/química , Inibidores da Protease de HIV/uso terapêutico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Animais , DNA/imunologia , Descoberta de Drogas , Feminino , Inibidores da Protease de HIV/farmacocinética , Inibidores da Protease de HIV/farmacologia , Humanos , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/imunologia , Glomérulos Renais/patologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Camundongos , Camundongos Endogâmicos NZB , Modelos MolecularesRESUMO
We briefly review the protective role of maternal antibodies during fetal development and at early postnatal stages. We describe antibody delivery to fetuses, particularly in the context of the developing blood-brain barrier (BBB), and present the essential concepts regarding the adult BBB, together with existing information on the prenatal developing BBB. We focus on maternal antibody transfer to the developing brain and the consequences of the presence of pathogenic antibodies at early stages of brain development on subsequent brain dysfunction.
Assuntos
Anticorpos/metabolismo , Barreira Hematoencefálica/imunologia , Encefalopatias/imunologia , Encéfalo/imunologia , Imunidade Materno-Adquirida , Adulto , Animais , Anticorpos/imunologia , Citotoxicidade Celular Dependente de Anticorpos , Encéfalo/embriologia , Feminino , Humanos , Exposição Materna/efeitos adversos , GravidezRESUMO
Patients with systemic lupus erythematosus (SLE) experience cognitive abnormalities in multiple domains including processing speed, executive function, and memory. Here we show that SLE patients carrying antibodies that bind DNA and the GluN2A and GluN2B subunits of the N-methyl-d-aspartate receptor (NMDAR), termed DNRAbs, displayed a selective impairment in spatial recall. Neural recordings in a mouse model of SLE, in which circulating DNRAbs penetrate the hippocampus, revealed that CA1 place cells exhibited a significant expansion in place field size. Structural analysis showed that hippocampal pyramidal cells had substantial reductions in their dendritic processes and spines. Strikingly, these abnormalities became evident at a time when DNRAbs were no longer detectable in the hippocampus. These results suggest that antibody-mediated neurocognitive impairments may be highly specific, and that spatial cognition may be particularly vulnerable to DNRAb-mediated structural and functional injury to hippocampal cells that evolves after the triggering insult is no longer present.
Assuntos
Autoanticorpos/metabolismo , Cognição , Receptores de N-Metil-D-Aspartato/imunologia , Percepção Espacial , Adulto , Animais , Anticorpos Antinucleares/imunologia , Membrana Celular/metabolismo , Dendritos/metabolismo , Feminino , Células HEK293 , Hipocampo/patologia , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Células Piramidais/metabolismo , Memória EspacialRESUMO
Systemic lupus erythematosus (SLE) is characterized by multiorgan inflammation, neuropsychiatric disorders (NPSLE), and anti-nuclear antibodies. We previously identified a subset of anti-DNA antibodies (DNRAb) cross-reactive with the N-methyl-D-aspartate receptor, present in 30% to 40% of patients, able to enhance excitatory post-synaptic potentials and trigger neuronal apoptosis. DNRAb+ mice exhibit memory impairment or altered fear response, depending on whether the antibody penetrates the hippocampus or amygdala. Here, we used 18F-fluorodeoxyglucose (FDG) microPET to plot changes in brain metabolism after regional blood-brain barrier (BBB) breach. In DNRAb+ mice, metabolism declined at the site of BBB breach in the first 2 weeks and increased over the next 2 weeks. In contrast, DNRAb- mice exhibited metabolic increases in these regions over the 4 weeks after the insult. Memory impairment was present in DNRAb+ animals with hippocampal BBB breach and altered fear conditioning in DNRAb+ mice with amygdala BBB breach. In DNRAb+ mice, we observed an inverse relationship between neuron number and regional metabolism, while a positive correlation was observed in DNRAb- mice. These findings suggest that local metabolic alterations in this model take place through different mechanisms with distinct time courses, with important implications for the interpretation of imaging data in SLE subjects.
Assuntos
Tonsila do Cerebelo/metabolismo , Anticorpos Antinucleares/metabolismo , Barreira Hematoencefálica/metabolismo , Hipocampo/metabolismo , Lúpus Eritematoso Sistêmico/metabolismo , Tonsila do Cerebelo/diagnóstico por imagem , Tonsila do Cerebelo/patologia , Animais , Comportamento Animal , Barreira Hematoencefálica/diagnóstico por imagem , Barreira Hematoencefálica/patologia , Modelos Animais de Doenças , Feminino , Fluordesoxiglucose F18 , Hipocampo/diagnóstico por imagem , Hipocampo/patologia , Lúpus Eritematoso Sistêmico/diagnóstico por imagem , Lúpus Eritematoso Sistêmico/patologia , Lúpus Eritematoso Sistêmico/psicologia , Camundongos , Camundongos Endogâmicos BALB C , Neurônios/metabolismo , Neurônios/patologia , Tomografia por Emissão de PósitronsRESUMO
Pivotal to brain development and function is an intact blood-brain barrier (BBB), which acts as a gatekeeper to control the passage and exchange of molecules and nutrients between the circulatory system and the brain parenchyma. The BBB also ensures homeostasis of the central nervous system (CNS). We report that germ-free mice, beginning with intrauterine life, displayed increased BBB permeability compared to pathogen-free mice with a normal gut flora. The increased BBB permeability was maintained in germ-free mice after birth and during adulthood and was associated with reduced expression of the tight junction proteins occludin and claudin-5, which are known to regulate barrier function in endothelial tissues. Exposure of germ-free adult mice to a pathogen-free gut microbiota decreased BBB permeability and up-regulated the expression of tight junction proteins. Our results suggest that gut microbiota-BBB communication is initiated during gestation and propagated throughout life.
Assuntos
Barreira Hematoencefálica , Intestinos/microbiologia , Microbiota , Animais , Feminino , Camundongos , Permeabilidade , Gravidez , Junções Íntimas/metabolismoRESUMO
This chapter describes methods utilized in establishing a mouse model of neuropsychiatric lupus encompassing both cognitive and emotional dysfunction, and a model of the influence of maternal antibody on the developing brain. The antibody of interest binds the N-methyl-D: -aspartate receptor (NMDAR), a receptor for glutamate that is a major excitatory neurotransmitter in the brain involved in synaptic plasticity, in memory and learning, and in emotional responses.We introduce basic concepts of these models and provide protocols for the following: (1) the induction of anti-dsDNA, anti-NMDAR antibodies, (2) testing serum antibody titer by ELISA, (3) breaching blood brain barrier (BBB) integrity with LPS and epinephrine, (4) passive transfer of pathology by injecting human and mouse brain-reactive antibodies into adult mouse as well as injecting the antibody into gestating mice and transfer of antibody from dam to fetus, (5) blocking NMDAR-mediated pathogenicity in vivo, (6) evacuation of blood from the brain by cardiac perfusion to preserve the brain for histology, (7) evaluating injured/apoptotic neurons in brain histology, (8) preparing membrane-enriched brain -fractions for NMDAR analysis.
Assuntos
Autoanticorpos/imunologia , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/patologia , Lúpus Eritematoso Sistêmico/imunologia , Biologia Molecular/métodos , Receptores de N-Metil-D-Aspartato/imunologia , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Western Blotting , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Epinefrina/farmacologia , Feminino , Humanos , Imunização , Imunização Passiva , Lipopolissacarídeos/farmacologia , Lúpus Eritematoso Sistêmico/patologia , Membranas/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Miocárdio/patologia , PerfusãoRESUMO
Systemic lupus erythematosus (SLE), a disease of women during childbearing years, is characterized by the production of double-stranded DNA antibodies. A subset of these antibodies, present in 40% of patients, cross-reacts with the NR2A and NR2B subunits of the N-methyl-d-aspartate receptor (NMDAR). In this study, we show that, in mouse models, these antibodies cause a loss of female fetus viability by inducing apoptosis of NR2A-expressing neurons within the brainstem late in fetal development; gender specificity derives from a time-dependent increased expression of NR2A in female brainstem or increased vulnerability of female fetal neurons to signaling through NR2A-containing NMDARs. This paradigm is consistent with available data on the sex ratio of live births of women with SLE. It represents a novel mechanism by which maternal autoantibodies can severely affect fetal health in a gender-specific fashion and raises the question of how many maternal antibodies affect brain development or exhibit gender-specific fetal effects.
Assuntos
Autoanticorpos/imunologia , Encéfalo/embriologia , Morte Fetal/imunologia , Animais , Animais Recém-Nascidos , Anticorpos Antinucleares/imunologia , Apoptose/genética , Apoptose/imunologia , Encéfalo/patologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neurônios/imunologia , Oligopeptídeos/imunologia , Oligopeptídeos/farmacologia , Gravidez , Receptores de N-Metil-D-Aspartato/genética , Fatores Sexuais , Razão de MasculinidadeRESUMO
Systemic lupus erythematosus (SLE) is an autoimmune disease mediated by autoantibodies and preferentially affecting women of childbearing age. Because the offspring of mothers with SLE show a high frequency of learning disorders, we hypothesized that maternally transferred autoantibodies that bind DNA and the N-methyl-D-aspartate receptor (NMDAR) could have a pathogenic role during fetal brain development. Here we describe a maternal SLE mouse model wherein pregnant dams harbored DNA-specific, NMDAR-specific autoantibodies throughout gestation. High titers of these autoantibodies in maternal circulation led to histological abnormalities in fetal brain and subsequent cognitive impairments in adult offspring. These data support a paradigm in which in utero exposure to neurotoxic autoantibodies causes abnormal brain development with long-term consequences. This paradigm may apply to multiple congenital neuropsychiatric disorders.