Animal Models Of Autoimmunity Research Articles

Mediators of Inflammation as Targets for Chronic Pain Treatment

Mediators of Inflammation as Targets for Chronic Pain Treatment

The Dendritic Cell Response to Classic, Emerging, and Homeostatic Danger Signals. Implications for Autoimmunity

Dendritic cells (DCs) initiate and control immune responses, participate in the maintenance of immunological tolerance and are pivotal players in the pathogenesis of autoimmunity. In patients with autoimmune disease and in experimental animal models of autoimmunity, DCs show abnormalities in both numbers and activation state, expressing immunogenic levels of costimulatory molecules and pro-inflammatory cytokines. Exogenous and endogenous danger signals activate DCs to stimulate the immune response. Classic endogenous danger signals are released, activated, or secreted by host cells and tissues experiencing stress, damage, and non-physiologic cell death; and are therefore referred to as damage-associated molecular patterns (DAMPs). Some DAMPs are released from cells, where they are normally sequestered, during necrosis (e.g., heat shock proteins, uric acid, ATP, HMGB1, mitochondria-derived molecules). Others are actively secreted, like Type I Interferons. Here we discuss important DAMPs in the context of autoimmunity. For some, there is a clear pathogenic link (e.g., nucleic acids and lupus). For others, there is less evidence. Additionally, we explore emerging danger signals. These include inorganic materials and man-made technologies (e.g., nanomaterials) developed as novel therapeutic approaches. Some nanomaterials can activate DCs and may trigger unintended inflammatory responses. Finally, we will review “homeostatic danger signals,” danger signals that do not derive directly from pathogens or dying cells but are associated with perturbations of tissue/cell homeostasis and may signal pathological stress. These signals, like acidosis, hypoxia, and changes in osmolarity, also play a role in inflammation and autoimmunity.

Microwave and magnetic (M2) proteomics of the experimental autoimmune encephalomyelitis animal model of multiple sclerosis

We hypothesized that quantitative MS/MS-based proteomics at multiple time points, incorporating rapid microwave and magnetic (M(2) ) sample preparation, could enable relative protein expression to be correlated to disease progression in the experimental autoimmune encephalomyelitis (EAE) animal model of multiple sclerosis. To test our hypothesis, microwave-assisted reduction/alkylation/digestion of proteins from brain tissue lysates bound to C8 magnetic beads and microwave-assisted isobaric chemical labeling were performed of released peptides, in 90 s prior to unbiased proteomic analysis. Disease progression in EAE was assessed by scoring clinical EAE disease severity and confirmed by histopathologic evaluation for central nervous system inflammation. Decoding the expression of 283 top-ranked proteins (p <0.05) at each time point relative to their expression at the peak of disease, from a total of 1191 proteins observed in four technical replicates, revealed a strong statistical correlation to EAE disease score, particularly for the following four proteins that closely mirror disease progression: 14-3-3ε (p = 3.4E-6); GPI (p = 2.1E-5); PLP1 (p = 8.0E-4); PRX1 (p = 1.7E-4). These results were confirmed by Western blotting, signaling pathway analysis, and hierarchical clustering of EAE risk groups. While validation in a larger cohort is underway, we conclude that M(2) proteomics is a rapid method to quantify putative prognostic/predictive protein biomarkers and therapeutic targets of disease progression in the EAE animal model of multiple sclerosis.

Transplanting of Mesenchymal Stem Cells May Affect Proliferation and Function of CD4+T Cells in Experimental Autoimmune Encephalomyelitis

To research the effects of transplanting mesenchymal stem cells on the development of experimental autoimmune encephalomyelitis and the mechanism behind it. An experimental autoimmune encephalomyelitis animal model was induced by injection of the MOG peptide, and mesenchymal stem cell injection was done 20 and 22 days after experimental autoimmune encephalomyelitis induction. Clinical scores were recorded daily to evaluate developing experimental autoimmune encephalomyelitis. The frequency of CD4(+)CD25(+)Foxp3(+)T cells in the spleen, the thymus, and the lymph nodes were analyzed by flow cytometry, and Foxp3, TGF-β1, and IL-10 mRNA were detected by reverse-transcription-polymerase chain reaction. Transplant of mesenchymal stem cells on experimental autoimmune encephalomyelitis mice led to a decreased clinical score, an up-regulation of CD4(+)CD25(+)Foxp3(+)T cells, Foxp3, TGF-β1, and IL-10 mRNA in the spleen, the lymph nodes, and the thymus as compared with experimental autoimmune encephalomyelitis mice. Transplant of mesenchymal stem cells may prevent developing experimental autoimmune encephalomyelitis and might be an available method in therapy of multiple sclerosis. Mesenchymal stem cells transplant may affect proliferation and function of CD4(+)T cells in experimental autoimmune encephalomyelitis, and CD4(+)CD25(+)Foxp3(+)T cell, Foxp3, TGF-β1, and IL-10 may be involved in this process.

EndoS, a “drug from a bug” as a novel treatment for autoimmunity of the blood

Pathogens have through co‐evolution become the true experts of our immune system and have during this process developed a multitude of strategies to manipulate the immune response. This is fundamental for the pathogens to persist and cause disease, but we can also exploit this nature’s own high throughput screening system as a source for novel biologicals to treat disease. We have identified several immunomodulating molecules from pathogens (PADIMMs) and here we present one example, the immunoglobulin glycan hydrolyzing enzyme EndoS from the human pathogen Streptococcus pyogenes. EndoS hydrolysis of IgG completely alters the effector functions of IgG, with reduced complement activation and altered binding to Fc‐receptors on white blood cells. When taken out of its infectious context, EndoS can be administered as an experimental drug in animal models of antibody‐mediated autoimmunity. We have been able to show that EndoS has a dramatic positive effects in several animal models of autoimmunity, including rheumatoid arthritis, systemic lupus erythematosus (SLE), and of particular interest for this forum, autoimmune hemolytic anemia (AIHA), and immune thrombocytopenic purpura (ITP). The hope is, by telling this story, to stimulate other researchers to join the “Drugs from Bugs” movement in the hunt for the immunomodulating biologicals of tomorrow.

IL-10-independent regulatory role for B cells in suppressing autoimmunity through GITRL-mediated maintenance of Tregs (176.18)

Abstract A regulatory role for B cells has been shown in animal models of autoimmunity and several studies suggested an IL-10-dependent mechanism. In our model of experimental autoimmune encephalomyelitis (EAE), WT mice exhibited a monophasic disease and recovered, but B cell deficiency, either genetic (µMT) or anti-CD20-mediated, led to unresolved EAE. Although B cells regulated EAE, we did not detect IL-10-producing B cells. Hence, we investigated IL-10-independent roles for B cells in immune regulation. B cell deficiency resulted in reduced numbers of CD4+Foxp3+ T regulatory cells (Tregs) in the periphery, suggesting involvement of B cells in their peripheral homeostasis. Interestingly, B cell depletion therapy in humans has been associated with the onset of autoimmunity. Likewise, reduction of Tregs post anti-CD20-mediated depletion of B cells resulted in spontaneous EAE and accelerated colitis in genetically susceptible mice. To study B cell-Treg interactions, we transferred B cells into µMT mice, which resulted in the proliferation and partial restoration of Treg numbers, sufficient for the resolution of EAE. Mechanistically, expression of glucocorticoid-induced tumor necrosis factor receptor-ligand (GITRL) by B cells was required, but IL-10 and B7 molecules were dispensable. Our results demonstrate a novel IL-10-independent role for B cells in regulating autoimmunity by maintenance of Tregs via GITRL.

Development and function of interleukin 17–producing γδ T cells

Interleukin (IL) 17 is a phylogenetically ancient cytokine that has been adopted by the adaptive immune system, and the investigation of adaptive T helper (Th) 17 cells has substantially contributed to our understanding of the molecular requirements for the induction, regulation, and function of IL-17. However, IL-17 is in fact produced by a large variety of innate immune cells and exerts its most significant biological functions at the interface of the organism with its environment, such as, for example, at epithelial surfaces, where γδ T cells are a prominent source of IL-17. In this review, we will give an overview on the concepts of commitment of γδ T cells to effector phenotypes, focusing on IL-17-producing γδ T cells (γδT17 cells). The role of γδT17 cells in animal models of autoimmunity will be discussed as well as the prerequisites for the development of human γδT17 cells and their potential importance for human disease conditions.

Dissecting complex epigenetic alterations in human lupus

Systemic lupus erythematosus is a chronic relapsing autoimmune disease that primarily afflicts women, and both a genetic predisposition and appropriate environmental exposures are required for lupus to develop and flare. The genetic requirement is evidenced by an increased concordance in identical twins and by the validation of at least 35 single-nucleotide polymorphisms predisposing patients to lupus. Genes alone, though, are not enough. The concordance of lupus in identical twins is often incomplete, and when concordant, the age of onset is usually different. Lupus is also not present at birth, but once the disease develops, it typically follows a chronic relapsing course. Thus, genes alone are insufficient to cause human lupus, and additional factors encountered in the environment and over time are required to initiate the disease and subsequent flares. The nature of the environmental contribution, though, and the mechanisms by which environmental agents modify the immune response to cause lupus onset and flares in genetically predisposed people have been controversial. Reports that the lupus-inducing drugs procainamide and hydralazine are epigenetic modifiers, that epigenetically modified T cells are sufficient to cause lupus-like autoimmunity in animal models, and that patients with active lupus have epigenetic changes similar to those caused by procainamide and hydralazine have prompted a growing interest in how epigenetic alterations contribute to this disease. Understanding how epigenetic mechanisms modify T cells to contribute to lupus requires an understanding of how epigenetic mechanisms regulate gene expression. The roles of DNA methylation, histone modifications, and microRNAs in lupus pathogenesis will be reviewed here.

W5-2 Lymphopenia-induced proliferation (LIP) triggers the development of follicular helper T (T&lt;sub&gt;FH&lt;/sub&gt;) cells which have a distinctive ontogeny and a critical role in aberrant B cell responses

Lymphopenia results in the homeostatic peripheral expansion of lymphocytes to maintain T cell homeostasis. Accumulating data show that lymphopenia-induced proliferation (LIP) has a pathogenic role in the development of autoimmunity in animal models and human systemic autoimmune diseases such as systemic lupus erythematosus, Sjögren's syndrome and rheumatoid arthritis. To clarify the mechanism of anti-nuclear antibodies (ANA) production, we established a lymphopenic mouse model in which CD4+ T cell subsets from wild-type BALB/c mice were adoptively injected into BALB/c nude mice, which induced IgG-type ANA production. We observed that class switching and ANA production were enhanced when regulatory T cells were depleted. We identified IL-21-producing PD-1+ TFH cells which develop from conventional T cells during LIP and drive germinal center reactions with aberrant B cell responses. Compared with traditional TFH cells, this subset has a distinctive ontogeny and a critical role in breaking B cell tolerance. This study reveals the physiological mechanism how immunological tolerance is maintained during LIP and would help to understand the pathogenesis of systemic autoimmune diseases.

Immune-Regulatory Mechanisms in Systemic Autoimmune and Rheumatic Diseases

Immune-Regulatory Mechanisms in Systemic Autoimmune and Rheumatic Diseases

Bowman–Birk inhibitor attenuates experimental autoimmune encephalomyelitis by delaying infiltration of inflammatory cells into the CNS

Bowman-Birk Inhibitor (BBI), a serine protease inhibitor derived from soybeans, has anti-inflammatory properties and is able to suppress the development of central nervous system (CNS) autoimmunity in animal models. Experimental autoimmune encephalomyelitis (EAE), a widely used animal model of multiple sclerosis (MS), is characterized by breakdown of the blood-brain barrier and infiltration of inflammatory cells into the CNS, resulting in pathology. In this study, we observed that BBI-treated mice showed delayed onset of EAE and reduced disease severity compared to control mice. BBI-treated mice had fewer inflammatory cells in the CNS including significantly reduced numbers of Th1 and Th17 cells. In the periphery, BBI treatment suppressed the development of encephalitogenic Th1 and Th17 responses early on [day 7 post-immunization (p.i.)], while after disease onset (day 14 p.i.) BBI-treated mice had stronger Th responses, as determined by antigen-specific proliferation and cytokine production. These results demonstrate that BBI treatment temporarily suppressed the development of encephalitogenic responses, but these responses eventually attained normal magnitude. Given that BBI-treated mice exhibited stronger encephalitogenic responses in the periphery during clinically manifesting EAE, delayed disease onset, and reduced numbers of CNS-infiltrating cells, it appears likely that BBI impedes the exit of pathogenic Th1 and Th17 cells from lymphoid organs, thereby delaying their migration into the CNS.

Autoreactive Antibodies and Loss of Retinal Ganglion Cells in Rats Induced by Immunization with Ocular Antigens

In an experimental autoimmune animal model, retinal ganglion cell (RGC) loss was induced through immunization with glaucoma-related antigens. The target of this study was to investigate the pathomechanism behind this decline and the serum antibody reactivity against ocular and neuronal tissues after immunization with glaucoma- and non-glaucoma-associated antigens. Rats immunized with optic nerve antigen homogenate (ONA) or keratin (KER) were compared to control rats (CO). Intraocular pressure (IOP) was measured, and the fundi were examined regularly. Four weeks afterward, cells were counted in retinal flat mounts. Retina, optic nerve, and brain sections from healthy animals and optic nerve sections from immunized animals were incubated with serum collected at different time points. The occurrence of autoreactive antibodies was examined. Signs of antibody deposits, microglia activation, and demyelination were sought in optic nerves of immunized animals. Brain sections were examined for abnormalities. No IOP or fundus changes were observed. Animals immunized with ONA showed a significant cell loss compared with the CO group. Elevated autoreactive antibodies against retina, optic nerve, and brain were observed. Animals immunized with KER, despite their immunologic response against KER, demonstrated neither RGC loss, nor increased development of autoreactive antibodies. Optic nerve from animals immunized with ONA demonstrated antibody accumulation, glia activation, and demyelination. No such observations were made in the KER or CO groups. Brain sections were without pathologic findings. Systemic autoimmunity against ocular and neuronal epitopes, mediated by accordant autoreactive antibodies, is involved in the inflammatory processes that cause RGC degeneration in this experimental animal model.

Intravenous administration of human embryonic stem cell-derived neural precursor cells attenuates cuprizone-induced central nervous system (CNS) demyelination

Previous studies have demonstrated the therapeutic potential for human embryonic stem cell-derived neural precursor cells (hES-NPCs) in autoimmune and genetic animal models of demyelinating diseases. Herein, we tested whether intravenous (i.v.) administration of hES-NPCs would impact central nervous system (CNS) demyelination in a cuprizone model of demyelination. C57Bl/6 mice were fed cuprizone (0.2%) for 2 weeks and then separated into two groups that either received an i.v. injection of hES-NPCs or i.v. administration of media without these cells. After an additional 2 weeks of dietary cuprizone treatment, CNS tissues were analysed for detection of transplanted cells and differences in myelination in the region of the corpus callosum (CC). Cuprizone-induced demyelination in the CC was significantly reduced in mice treated with hES-NPCs compared with cuprizone-treated controls that did not receive stem cells. hES-NPCs were identified within the brain tissues of treated mice and revealed migration of transplanted cells into the CNS. A limited number of human cells were found to express the mature oligodendrocyte marker, O1, or the astrocyte marker, glial fibrillary acidic protein. Reduced apoptosis and attenuated microglial and astrocytic responses were also observed in the CC of hES-NPC-treated mice. These findings indicated that systemically administered hES-NPCs migrated from circulation into a demyelinated lesion within the CNS and effectively reduced demyelination. Observed reductions in astrocyte and microglial responses, and the benefit of hES-NPC treatment in this model of myelin injury was not obviously accountable to tissue replacement by exogenously administered cells.

Infection and autoimmunity: Lessons of animal models

While the key initiating processes that trigger human autoimmune diseases remain enigmatic, increasing evidences support the concept that microbial stimuli are among major environmental factors eliciting autoimmune diseases in genetically susceptible individuals. Here, we present an overview of evidences obtained through various experimental models of autoimmunity for the role of microbial stimuli in disease development. Disease onset and severity have been compared in numerous models under conventional, specific-pathogen-free and germ-free conditions. The results of these experiments suggest that there is no uniform scheme that could describe the role played by infectious agents in the experimental models of autoimmunity. While some models are dependent, others prove to be completely independent of microbial stimuli. In line with the threshold hypothesis of autoimmune diseases, highly relevant genetic factors or microbial stimuli induce autoimmunity on their own, without requiring further factors. Importantly, recent evidences show that colonization of germ-free animals with certain members of the commensal flora [such as segmented filamentous bacteria (SFB)] may lead to autoimmunity. These data drive attention to the importance of the complex composition of gut flora in maintaining immune homeostasis. The intriguing observation obtained in autoimmune animal models that parasites often confer protection against autoimmune disease development may suggest new therapeutic perspectives of infectious agents in autoimmunity.

Epigenetic alterations and autoimmune disease.

Recent advances in epigenetics have enhanced our knowledge of how environmental factors (UV radiation, drugs, infections, etc.) contribute to the development of autoimmune diseases (AID) in genetically predisposed individuals. Studies conducted in monozygotic twins discordant for AID and spontaneous autoimmune animal models have highlighted the importance of DNA methylation changes and histone modifications. Alterations in the epigenetic pattern seem to be cell specific, as CD4+ T cells and B cells are dysregulated in systemic lupus erythematosus, synovial fibroblasts in rheumatoid arthritis and cerebral cells in multiple sclerosis. With regard to lymphocytes, the control of tolerance is affected, leading to the development of autoreactive cells. Other epigenetic processes, such as the newly described miRNAs, and post-translational protein modifications may also be suspected. Altogether, a conceptual revolution is in progress, in AID, with potential new therapeutic strategies targeting epigenetic patterns.

Antigen-based therapy with glutamic acid decarboxylase (GAD) vaccine in patients with recent-onset type 1 diabetes: a randomised double-blind trial

Glutamic acid decarboxylase (GAD) is a major target of the autoimmune response that occurs in type 1 diabetes mellitus. In animal models of autoimmunity, treatment with a target antigen can modulate aggressive autoimmunity. We aimed to assess whether immunisation with GAD formulated with aluminum hydroxide (GAD-alum) would preserve insulin production in recent-onset type 1 diabetes. Patients aged 3-45 years who had been diagnosed with type 1 diabetes for less than 100 days were enrolled from 15 sites in the USA and Canada, and randomly assigned to receive one of three treatments: three injections of 20 μg GAD-alum, two injections of 20 μg GAD-alum and one of alum, or 3 injections of alum. Injections were given subcutaneously at baseline, 4 weeks later, and 8 weeks after the second injection. The randomisation sequence was computer generated at the TrialNet coordinating centre. Patients and study personnel were masked to treatment assignment. The primary outcome was the baseline-adjusted geometric mean area under the curve (AUC) of serum C-peptide during the first 2 h of a 4-h mixed meal tolerance test at 1 year. Secondary outcomes included changes in glycated haemoglobin A(1c) (HbA(1c)) and insulin dose, and safety. Analysis included all randomised patients with known measurements. This trial is registered with ClinicalTrials.gov, number NCT00529399. 145 patients were enrolled and treated with GAD-alum (n=48), GAD-alum plus alum (n=49), or alum (n=48). At 1 year, the 2-h AUC of C-peptide, adjusted for age, sex, and baseline C-peptide value, was 0·412 nmol/L (95% CI 0·349-0·478) in the GAD-alum group, 0·382 nmol/L (0·322-0·446) in the GAD-alum plus alum group, and 0·413 nmol/L (0·351-0·477) in the alum group. The ratio of the population mean of the adjusted geometric mean 2-h AUC of C-peptide was 0·998 (95% CI 0·779-1·22; p=0·98) for GAD-alum versus alum, and 0·926 (0·720-1·13; p=0·50) for GAD-alum plus alum versus alum. HbA(1c), insulin use, and the occurrence and severity of adverse events did not differ between groups. Antigen-based immunotherapy therapy with two or three doses of subcutaneous GAD-alum across 4-12 weeks does not alter the course of loss of insulin secretion during 1 year in patients with recently diagnosed type 1 diabetes. Although antigen-based therapy is a highly desirable treatment and is effective in animal models, translation to human autoimmune disease remains a challenge. US National Institutes of Health.

Autologous haemopoietic stem cell transplantation for autoimmune diseases

Introduction: Autoimmune diseases are signified by complex errors of immune-regulation, and the development of autoreactive T and B cells targeting self-antigens, which eventually can lead to permanent organ damage. Despite novel therapeutic protocols, the disease course is chronic, debilitating and in some instances the outcome is lethal. Previously, stem cell transplantation has been reported to be beneficial in autoimmune animal models, as well as in autoimmune diseases related to hematological abnormalities, which opened potential new avenues in the treatment of human autoimmune diseases.Areas covered: In this review, the authors describe the compound cellular regulatory effects of autologous hemopoietic stem cell transplantation (ASCT) and also clinical observations, related to the therapy in a variety of organ-specific and systemic autoimmune diseases.Expert opinion: ASCT has a broad effect on the re-populated immune system, complex regulatory potentials and long term beneficial effect via down-regulating immune-reactivity, yet its widespread use in autoimmune diseases is limited, mostly due to the serious side-effects of the conditioning treatments. However, in certain autoimmune diseases with severe debilitating, or even life-threatening course, including systemic lupus erythematosus, systemic sclerosis or multiple sclerosis, ASCT can be a reasonable choice when conventional therapy has failed.

T helper (Th)1, Th2, and Th17 interleukin pathways in infertile patients with minimal/mild endometriosis

In the present study, interleukin (IL)-10, IL-12, IL-17, and IL-23 levels were measured in serum and peritoneal fluid of women with minimal or mild endometriosis and compared with levels in controls without endometriosis. Higher IL-23 levels were encountered in the peritoneal fluid of women with endometriosis, suggesting a possible role of this cytokine in these women's infertility.

HE3286, an orally bioavailable synthetic analogue of an active DHEA metabolite suppresses spontaneous autoimmune diabetes in the non-obese diabetic (NOD) mouse

5-Androstene-3β,7β,17β-triol (AET) is a naturally occurring anti-inflammatory adrenal steroid that limits acute and chronic inflammation. HE3286 (17α-ethynyl-5-androstene-3β,7β,17β-triol) is a synthetic derivative of AET with improved pharmaceutical properties and efficacy in some animal models of autoimmunity. Here, daily oral doses of HE3286 led to a suppression of spontaneous autoimmune diabetes in the non-obese diabetic mouse model of type 1 diabetes mellitus when administered either shortly before or after the first incidence of disease onset. Efficacy was associated with reduced insulitis and a suppression of the pathogenic T helper cell type 1 and type 17 phenotypes in peripheral lymphoid organs. These results demonstrate that daily oral treatment with HE3286 administrated relatively late in the destructive autoimmune process led to a suppression of type 1 diabetes mellitus onset and of the pathological inflammatory status, supporting its clinical evaluation in type 1 diabetes mellitus subjects.

Regulatory T Cells Require Mammalian Target of Rapamycin Signaling To Maintain Both Homeostasis and Alloantigen-Driven Proliferation in Lymphocyte-Replete Mice

Rapamycin (Rapa), an immunosuppressive drug that acts through mammalian target of Rapa inhibition, broadly synergizes with tolerogenic agents in animal models of transplantation and autoimmunity. Rapa preferentially inhibits conventional CD4(+) Foxp3(-) T cells (Tconv) and promotes outgrowth of CD4(+)Foxp3(+) regulatory T cells (Treg) during in vitro expansion. Moreover, Rapa is widely perceived as augmenting both expansion and conversion of Treg in vivo. However, most quantitative studies were performed in lymphopenic hosts or in graft-versus-host disease models. We show in this study that in replete wild-type mice, Rapa significantly inhibits both homeostatic and alloantigen-induced proliferation of Treg, and promotes their apoptosis. Together, these lead to significant Treg depletion. Tconv undergo depletion to a similar degree, resulting in no change in the percent of Treg among CD4 cells. Moreover, in this setting, there was no evidence of conversion of Tconv into Treg. However, after withdrawal of Rapa, Treg recover Ag-induced proliferation more quickly than Tconv, leading to recovery to baseline numbers and an increase in the percent of Treg compared with Tconv. These findings suggest that the effects of Rapa on Treg survival, homeostasis, and induction, depend heavily on the cellular milieu and degree of activation. In vivo, the resistance of Treg to mammalian target of Rapa inhibition is relative and results from lymphopenic and graft-versus-host disease models cannot be directly extrapolated to settings more typical of solid organ transplantation or autoimmunity. Moreover, these results have important implications for the timing of Rapa therapy with tolerogenic agents designed to increase the number of Treg in vivo.