Continuous administration of anti-interleukin 10 antibodies delays onset of autoimmunity in NZB/W F1 mice

Concomitant use of interleukin-2 and tacrolimus suppresses follicular helper T cell proportion and exerts therapeutic effect against lupus nephritis in systemic lupus erythematosus-like chronic graft versus host disease

Introduction

Defective interleukin-2 (IL-2) production contributes to immune system imbalance in patients with systemic erythematosus lupus (SLE). Recent clinical studies suggested that low-dose IL-2 treatment is beneficial for SLE and the therapeutic effect is associated with regulatory T cell (Treg) expansion. Pharmacological calcineurin inhibition induces a reduction in the number of Tregs because they require stimulation of T cell receptor signaling and IL-2 for optimal proliferation. However, the activation of T cell receptor signaling is partially dispensable for the expansion of Tregs, but not for that of conventional T cells if IL-2 is present.

Aim

We examined whether addition of IL-2 restores the Treg proportion even with concurrent use of a calcineurin inhibitor and if the follicular helper T cell (Tfh) proportion is reduced in an SLE-like murine chronic graft versus host disease model.

Methods

Using a parent-into-F1 model, we investigated the effect of IL-2 plus tacrolimus on Treg and Tfh proportions and the therapeutic effect.

Results

Treatment with a combination of IL-2 and tacrolimus significantly delayed the initiation of proteinuria and decreased the urinary protein concentration, whereas tacrolimus or IL-2 monotherapy did not significantly attenuate proteinuria. Phosphorylation of signal transducer and activator of transcription 3, a positive regulator of Tfh differentiation, was reduced by combination treatment, whereas phosphorylation of signal transducer and activator of transcription 5, a negative regulator, was not reduced.

Conclusion

Addition of calcineurin inhibitors as adjunct agents may be beneficial for IL-2-based treatment of lupus nephritis.

Interrelation of T cell cytokines and autoantibodies in systemic lupus erythematosus: A cross-sectional study

T-helper cytokines interferon gamma (IFNɣ), interleukin 17 (IL-17) and IL-10 impact systemic lupus erythematosus (SLE) directly and indirectly via modulation of autoAb production. We determined the separate and combined effects on clinical manifestations of SLE (N = 62). IFNɣ, IL-17 but not IL-10 were significantly elevated in patients with SLE. IFNɣ positively correlated with anti-DNA and anti-SSA. IL-17 positively correlated with anti-SSA and was significantly higher in patients with discoid rash and class V LN. IL-10 did not correlate with circulating autoantibodies but was significantly elevated in patients with LN. Patients with LN had elevated plasma levels of anti-DNA and anti-Sm/ribonuclear protein (RNP). Anti-Sm/RNP levels were decreased in patients with acute mucocutaneous manifestations, including photosensitivity and/or malar rash. The study provides critical insights into pathological mechanisms of LN, which could help guide future diagnoses and therapies.

IL-10 revisited in systemic lupus erythematosus

IL-10 is a cytokine with pleiotropic functions, particularly known for its suppressive effects on various immune cells. Consequently, it can limit the pathogenesis of inflammatory diseases, such as multiple sclerosis (MS), inflammatory bowel disease, Crohn’s disease, and Epidermolysis bullosa acquisita, among others. Recent evidence however indicates that it plays dual roles in Systemic lupus Erythematosus (SLE) where it may inhibit pro-inflammatory effector functions but seems to be also a main driver of the extrafollicular antibody response, outside of germinal centers (GC). In line, IL-10 promotes direct differentiation of activated B cells into plasma cells rather than stimulating a GC response. IL-10 is produced by B cells, myeloid cells, and certain T cell subsets, including extrafollicular T helper cells, which are phenotypically distinct from follicular helper T cells that are relevant for GC formation. In SLE patients and murine lupus models extrafollicular T helper cells have been reported to support ongoing extrafollicular formation of autoreactive plasma cells, despite the presence of GCs. Here, we discuss the role of IL-10 as driver of B cell responses, its impact on B cell proliferation, class switch, and plasma cells.

Immunomodulatory Activity of Mesenchymal Stem Cells in Lupus Nephritis: Advances and Applications

Lupus nephritis (LN) is a significant cause of various acute and chronic renal diseases, which can eventually lead to end-stage renal disease. The pathogenic mechanisms of LN are characterized by abnormal activation of the immune responses, increased cytokine production, and dysregulation of inflammatory signaling pathways. LN treatment is an important issue in the prevention and treatment of systemic lupus erythematosus. Mesenchymal stem cells (MSCs) have the advantages of immunomodulation, anti-inflammation, and anti-proliferation. These unique properties make MSCs a strong candidate for cell therapy of autoimmune diseases. MSCs can suppress the proliferation of innate and adaptive immune cells, such as natural killer cells (NKs), dendritic cells (DCs), T cells, and B cells. Furthermore, MSCs suppress the functions of various immune cells, such as the cytotoxicity of T cells and NKs, maturation and antibody secretion of B cells, maturation and antigen presentation of DCs, and inhibition of cytokine secretion, such as interleukins (ILs), tumor necrosis factor (TNF), and interferons (IFNs) by a variety of immune cells. MSCs can exert immunomodulatory effects in LN through these immune functions to suppress autoimmunity, improve renal pathology, and restore kidney function in lupus mice and LN patients. Herein, we review the role of immune cells and cytokines in the pathogenesis of LN and the mechanisms involved, as well as the progress of research on the immunomodulatory role of MSCs in LN.

T Cell Homeostatic Proliferation Promotes a Redox State That Drives Metabolic and Epigenetic Upregulation of Inflammatory Pathways in Lupus

Significance: Numerous abnormalities in T cells have been described in patients with systemic lupus erythematosus (SLE), including lymphopenia, DNA demethylation, expression of endogenous retroviruses (ERVs), increased cell death, enlarged mitochondria, production of reactive oxygen species (ROS), and the appearance of unusual CD4^-CD8^- T cells. Our studies propose a model in which accelerated homeostatic proliferation of T cells promotes an epigenetic and metabolic program, leading to this cluster of abnormalities. Recent Advances: Growing knowledge of the innate immune disorders in SLE has included increased mitochondrial size and ROS production that induces oligomerization of the mitochondrial antiviral signaling (MAVS) protein and type I interferon production, as well as DNA demethylation, upregulation of inflammatory genes, and expression of certain ERVs in SLE peripheral blood mononuclear cells. All these events are part of the cellular program that occurs during homeostatic proliferation of T cells. Evidence from a murine model of SLE as well as in human SLE reveals that increased T cell homeostatic proliferation may be a driving factor in these processes. Critical Issues: Despite extensive knowledge of the myriad autoantibodies in SLE and other immune abnormalities, a cogent model has been lacking to link the numerous and seemingly disparate immune aberrations. This may partly explain the general lack of new drugs specifically for SLE in over 50 years. A more coherent model of SLE would not only unify the variety of immune abnormalities is SLE but would also suggest new therapies. Future Directions: The model of augmented homeostatic proliferation leading to increased mitochondrial mass, ROS, DNA demethylation, and upregulation of inflammatory genes suggests strategic new targets for SLE, including antioxidants and certain inhibitors of metabolism. Antioxid. Redox Signal. 36, 410-422.

Anti-TLR7 Antibody Protects Against Lupus Nephritis in NZBWF1 Mice by Targeting B Cells and Patrolling Monocytes

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and multiple organ damage. Toll-like receptor 7 (TLR7), an innate immune RNA sensor expressed in monocytes/macrophages, dendritic cells (DCs), and B cells, promotes disease progression. However, little is known about the cellular mechanisms through which TLR7 drives lupus nephritis. Here, we show that the anti-mouse TLR7 mAb, but not anti-TLR9 mAb, protected lupus-prone NZBWF1 mice from nephritis. The anti-TLR7 mAb reduced IgG deposition in glomeruli by inhibiting the production of autoantibodies to the RNA-associated antigens. We found a disease-associated increase in Ly6C^low patrolling monocytes that expressed high levels of TLR7 and had upregulated expression of lupus-associated IL-10, CD115, CD31, and TNFSF15 in NZBWF1 mice. Anti-TLR7 mAb abolished this lupus-associated increase in patrolling monocytes in the circulation, spleen, and glomeruli. These results suggested that TLR7 drives autoantibody production and lupus-associated monocytosis in NZBWF1 mice and, that anti-TLR7 mAb is a promising therapeutic tool targeting B cells and monocytes/macrophages.

Advances in therapeutic targets-related study on systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic and autoimmunity-mediated diffuse connective tissue disease. The mainstay of treatments for SLE mainly relies on corticosteroids and immunosuppressants, which have a series of unavoidable side effects. Therefore, it is of fundamental importance to search novel therapeutic targets for better treatment with favorable efficacy and minor side effects. Recent studies shed light on potential therapeutic targets for SLE, mainly covering the followings: B-cell/plasmocyte-related targets [B cell activating factor (BAFF), a proliferation-inducing ligand (APRIL), CD20, CD22, CD19/FcγRIIb, Bruton tyrosine kinase (Btk), and proteasome], T cell-related targets [calcineurin, mammalian target of rapamycin (mTOR), regulatory factor X1 (RFX1), and Rho kinase], macrophage-related targets (macrophage migration inhibitory factor), intracellular signaling molecules, cytokines (cereblon, histone deacetylase 6, Janus activated kinase/signal transducer and activator of transcription), co-stimulating factors (CD28/B7, CD40/CD154), IgE autoantibody, and gut microbiome. Among them, belimumab (a humanized monoclonal antibody against B-lymphocyte stimulator) and telitacicept (a recombinant human B-lymphocyte stimulator receptor-antibody fusion protein) have been sequentially approved for the clinical treatment of SLE in China. A variety of new targeted-therapy drugs are in the Phase 2 or Phase 3 clinical trials,among which anifrolumab (a human monoclonal antibody against type I interferon receptor subunit 1) has completed a Phase 3 clinical trial with good responses achieved, although its incidence of herpes zoster is higher than that in the control group. The research progress in both molecular mechanisms and new drug development for different therapeutic targets have greatly promoted our better and in-depth understanding of the pathogenesis of SLE, and have also reflected the complexity and heterogeneity of the disease. Successful development and clinical application of more novel therapies would no doubt usher in a new era of individualized treatment for SLE in the future.

IL-10 as a Th2 Cytokine: Differences Between Mice and Humans

The discovery of IL-10 more than 30 years ago marked the beginning of our understanding of how cytokines regulate immune responses, based on cross-regulation between Th1 and Th2 cytokines. Although multiple cell types were shown to produce IL-10, its identity as a Th2 cytokine remained strong because it was rigidly associated with Th2 clones in mice, whereas both Th1 and Th2 clones could secrete IL-10 in humans. However, as new Th1/Th2 cell functionalities emerged, anti-inflammatory action of IL-10 gained more attention than its inhibitory effect on Th1 cells, which may occur as an indirect consequence of suppression of APCs. This notion is also supported by the discovery of regulatory T cells, whose suppressor functions involve the mediation of IL-10, among other molecules. From this perspective, we discuss the functionalities of IL-10 by highlighting important differences between mice and humans with an emphasis on the Th1 and Th2 paradigm.

The DNA co-vaccination using Sm antigen and IL-10 as prophylactic experimental therapy ameliorates nephritis in a model of lupus induced by pristane

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies such as anti-Sm. Studies in patients with SLE and murine models of lupus reveal that the most critical anti-Sm autoantibodies are predominantly direct against D1_(83–119), D2, and B´/B epitopes.

Objectives

The present study aimed to analyze the induction of antigen-specific tolerance after prophylactic immunization with a DNA vaccine encoding the epitopes: D1_83-119, D2, B´/B, and B´/B_COOH in co-vaccination with IFN-γ or IL-10 in a murine model of lupus induced by pristane.

Material and methods

To obtain endotoxin-free DNA vaccines, direct cloning techniques using pcDNA were performed: D1_83-119, D2, B´/B, B´/B_COOH, IFN-γ, or IL-10. Lupus was induced by 0.5 mL of pristane via intraperitoneal in BALB/c female mice. Immunoprecipitation with K562 cells was metabolically labeled with ³⁵S and ELISA to detect serum antibodies or mice IgG1, IgG2a isotypes. ELISA determined IL-10 and IFN-γ from splenocytes supernatants. Proteinuria was assessed monthly, and lupus nephritis was evaluated by immunofluorescence, and electron microscopy.

Results

The prophylactic co-vaccination with D2/IL-10 reduced the expression of kidney damage observed by electron microscopy, direct immunofluorescence, and H & E, along with reduced level of anti-nRNP/Sm antibodies (P = 0.048).

Conclusion

The prophylactic co-vaccination of IL-10 with D2 in pristane-induced lupus ameliorates the renal damage maybe by acting as prophylactic DNA tolerizing therapy.

Roles of IL-1 and IL-10 family cytokines in the progression of systemic lupus erythematosus: Friends or foes?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that can affect nearly every organ system in the body. Besides genetic and environmental factors, unbalanced pro-inflammatory and anti-inflammatory cytokines contribute to immune dysregulation, trigger an inflammatory response, and induce tissue and organ damage. Inflammatory responses in SLE can be promoted and/or maintained by the availability of cytokines that are overproduced systemically and/or in local tissues. Several key cytokines have been considered potential targets for the reduction of chronic inflammation in SLE. Recent studies indicated that dysregulated production of several cytokines, including those of the IL-1 family and IL-10 family, orchestrate immune activation and self-tolerance, play critical roles in the pathogenesis of SLE. Among IL-1 family cytokines, IL-1, IL-18, IL-33, IL-36, IL-37, and IL-38 had been the most thoroughly investigated in SLE. Additionally, IL-10 family cytokines, IL-10, IL-20, IL-22, IL-26, IL-28, and IL-29 are dysregulated in SLE. Therefore, a better understanding of the initiation and progression of SLE may provide suitable novel targets for therapeutic intervention. In this review, we discuss the involvement of inflammation in the pathogenesis of SLE, with a focus on IL-1 family and IL-10 family cytokines, and highlight pathophysiological approaches and therapeutic potential for treating SLE.

AIM2 deficiency in B cells ameliorates systemic lupus erythematosus by regulating Blimp-1-Bcl-6 axis-mediated B-cell differentiation

Absent in melanoma 2 (AIM2) has been reported to be a component of inflammasomes in innate immune cells. Surprisingly, AIM2 is expressed by B cells, and higher AIM2 expression is observed in the B cells from lupus patients. To date, the inflammasome-independent function of AIM2 in B cells remains unclear. Here, we report increased expression of AIM2 in human tonsil memory and germinal center (GC) B cells and in memory B cells and plasma cells from the circulation and skin lesions of lupus patients. Conditional knockout of AIM2 in B cells reduces the CD19⁺ B-cell frequency in lymph nodes and spleens, and dampens KLH-induced IgG1-antibody production. In a pristane-induced mouse model of lupus, AIM2 deficiency in B cells attenuates lupus symptoms and reduces the frequency of GC B cells, T follicular helper (Tfh) cells, plasmablast cells, and plasma cells. Furthermore, the loss of AIM2 in human B cells leads to the increased expression of Blimp-1 and reduces the expression of Bcl-6. However, the silencing of Blimp-1 and Bcl-6 has no significant effect on AIM2 expression, indicating that AIM2 might be the upstream regulator for Blimp-1 and Bcl-6. In addition, IL-10 is found to upregulate AIM2 expression via DNA demethylation. Together, our findings reveal that AIM2 is highly expressed in the B cells of lupus patients and promotes B-cell differentiation by modulating the Bcl-6–Blimp-1 axis, providing a novel target for SLE treatment.

Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

Immune Cell Landscape Identification Associates Intrarenal Mononuclear Phagocytes With Onset and Remission of Lupus Nephritis in NZB/W Mice

Objective

A challenging issue in the clinical management of lupus nephritis (LN) is the resistance to immunosuppressive therapy. We postulated that perturbed intrarenal immune cell landscape affected LN onset and remission induction, and shedding light on the characteristics of intrarenal immune cell infiltration could cultivate more efficient treatment regimens.

Materials and Methods

Genome-wide expression profiles of microarray datasets were downloaded from the Gene Expression Omnibus database. The CIBERSORT algorithm was used to analyze the intrarenal immune cell landscape, followed by Pearson correlation analysis and principal component analysis. The differentially expressed genes were identified and subjected to Gene Ontology (GO) enrichment analyses and protein-protein interaction network establishment, being visualized by Cytoscape and further analyzed by CytoHubba to extract hub genes. Hub genes were also validated in the genomic dataset from kidney biopsy-proven LN patients.

Results

In addition to memory B cells, monocytes and M1 macrophages were identified as two predominantly increased intrarenal immune cell types in LN-prone NZB/W mice upon nephritis onset. Most interestingly, apart from memory B cells, monocytes and M1 macrophages proportions in kidney tissue were significantly lower in early remission mice compared with late remission mice. Furthermore, GO analysis showed that intrarenal mononuclear phagocytes triggered nephritis onset mainly via the initiation of adaptive immune response and inflammatory reaction, but this functional involvement was mitigated upon remission induction. Hub genes related to LN onset in NZB/W mice were validated in the genomic dataset from kidney biopsy-proven LN patients.

Conclusion

LN characterizes aberrant mononuclear phagocytes abundance and signature upon disease onset, of which the reversal is associated with early remission induction in LN-prone NZB/W mice. Mononuclear phagocytes might be an adjunctive histology marker for monitoring disease onset and stratifying LN patients in terms of response to remission induction therapy.

Low Levels of Vitamin D Promote Memory B Cells in Lupus

Background: Vitamin D deficiency is a known risk factor for Systemic Lupus Erythematosus (SLE), yet clinical trials have not demonstrated efficacy and few studies have utilized lupus models to understand the mechanism underlying this relationship. The Act1-/- mouse is a spontaneous model of lupus and Sjögren's syndrome, characterized by increased Th17 cells and peripheral B cell expansion. Vitamin D3 has anti-inflammatory properties, reduces Th17 cells and impairs B cell differentiation/activation. Therefore, we assessed how varying amounts of vitamin D3 affected lupus-like disease in the Act1-/- mouse. Methods: Act1-/- mice were fed either low/restricted (0 IU/kg), normal (2 IU/kg), or high/supplemented (10 IU/kg) vitamin D3 chow for 9 weeks, after which lupus-like features were analyzed. Results: While we found no differences in Th17 cells between vitamin D3 groups, vitamin D3 restriction specifically promoted memory B cell development, accompanied by elevated levels of serum IgM, IgG1, IgG3, and anti-dsDNA IgG. A similar significant negative association between serum vitamin D and memory B cells was confirmed in a cohort of SLE patients. Conclusion: Low levels of vitamin D3 are associated with elevated levels of memory B cells in an animal model of lupus and well-controlled SLE patients.

IL-10 producing regulatory and helper T-cells in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease characterised by the production of pathogenic autoantibodies against nuclear self-antigens. The anti-inflammatory and tolerogenic cytokine Interleukin-10 appears to play a paradoxical pathogenic role in SLE and is therefore currently therapeutically targeted in clinical trials. It is generally assumed that the pathogenic effect of IL-10 in SLE is due to its growth and differentiation factor activity on autoreactive B-cells, but effects on other cells might also play a role. To date, a unique cellular source of pathogenic IL-10 in SLE has not been identified. In this review, we focus on the contribution of different CD4⁺T-cell subsets to IL-10 and autoantibody production in SLE. In particular, we discuss that IL-10 produced by different subsets of adaptive regulatory T-cells, follicular helper T-cells and extra-follicular B-helper T-cells is likely to have different effects on autoreactive B-cell responses. A better understanding of the role of IL-10 in B-cell responses and lupus would allow to identify the most promising therapies for individual SLE patients in the future.

Epigenetic and transcriptional mechanisms for the regulation of IL-10

IL-10 is a critical immunoregulatory cytokine expressed in virtually all immune cell types. Maintaining a delicate balance between effective immune response and tolerance requires meticulous and dynamic control of IL-10 expression both epigenetically and transcriptionally. In this Review, we describe the epigenetic mechanisms controlling IL-10 expression, including chromatin remodeling, 3D chromatin loops, histone modification and DNA methylation. We discuss the role of transcription factors in directing chromatin modifications, with a special highlight on the emerging concept of pioneer transcription factors in setting up the chromatin landscape in T helper cells for IL-10 induction. Besides summarizing the recent progress on transcriptional regulation in specialized IL-10 producers such as type 1 regulatory T cells, regulatory B cells and regulatory innate lymphoid cells, we also discuss common transcriptional mechanisms for IL-10 regulation that are shared with other IL-10 producing cells.

Heightened TLR7/9-Induced IL-10 and CXCL13 Production with Dysregulated NF-ҝB Activation in CD11chiCD11b+ Dendritic Cells in NZB/W F1 Mice

Systemic lupus erythematosus (SLE) is a chronic, multifactorial autoimmune disease that predominantly affects young females. Dysregulation of different immune cell populations leads to self-tolerance breakdown and subsequent multiple organ damage as the disease develops. Plasmacytoid dendritic cells (pDCs) are potent producers of type I interferon (IFN), while myeloid dendritic cells (mDCs) are more specialized in antigen presentations. We have previously reported that bone-marrow (BM)-derived pDCs from the murine lupus model New Zealand black/white F1 (BWF1) possess abnormalities. Therefore, this study continues to investigate what aberrant properties peripheral pDCs and mDCs possess in BWF1 and how they mediate SLE progression, by comparing their properties in pre-symptomatic and symptomatic mice. Results showed that CD11c^hiCD11b⁺ myeloid DCs expanded during the disease state with down-regulation of co-stimulatory molecules and major histocompatibility complex class II molecules (MHC II), but their capacity to stimulate T cells was not hampered. During the disease state, this subset of mDCs displayed heightened toll-like receptors 7 and 9 (TLR 7/9) responses with increased interleukin 10 (IL-10) and C-X-C motif chemokine ligand 13 (CXCL13) expressions. Moreover, the expressions of myeloid differentiation primary response 88 (Myd88) and nuclear factor kappa B subunit 1 (Nfkb1) were higher in CD11c^hiCD11b⁺ DCs at the disease stage, leading to higher nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 phosphorylation activity. In summary, we reported aberrant phenotypic properties with enhanced TLR7/9 responses of CD11c^hiCD11b⁺ DCs in SLE mediated by aberrant NF-κB signaling pathway. Our findings add additional and novel information to our current understanding of the role of DCs in lupus immunopathogenesis. Lastly, molecular candidates in the NF-κB pathway should be exploited for developing therapeutic targets for SLE.

Tetra-arsenic tetra-sulfide ameliorates lupus syndromes by inhibiting IL-17 producing double negative T cells

Systemic lupus erythematosus (SLE) is an autoimmune disease of uncertain etiology that affects multiple tissues and organs. Tetra-arsenic tetra-sulfide (As₄ S₄ ), a traditional Chinese medicine, is effective on acute promyelocytic leukemia with mild side effects. In our previous study, BXSB lupus-prone mice treated with As₄ S₄ has showed improved monocytosis, decreased serum interleukin (IL)-6 and suppressed skin, liver and renal lesions with well-tolerance. In this study, we explored the effect and mechanism of As₄ S₄ on the MRL/lpr mice. MRL/lpr and wild MRL/MpJ mice were divided into control and As₄ S₄ treatment groups and dosed with As₄ S₄ or placebo for 8 weeks. We found that As₄ S₄ prevented the skin, renal and lung lesions of MRL/lpr mice. As₄ S₄ significantly decreased the double negative T (DN T) cells and reduced the serum levels of IL-17, IL-10, and antinuclear antibodies titer. Further results revealed that the FasL was decreased, and activated caspases elevated in DN T cells in As₄ S₄ treated MRL/lpr mice. Taken together, As₄ S₄ could selectively suppresses DN T cells by inducing apoptosis. It also reduced inflammatory cytokines IL-17, which may be produced by DN T cells. As₄ S₄ may represent a new therapy for SLE.

The Role of CD38 on the Function of Regulatory B Cells in a Murine Model of Lupus

Previous work from our group has shown that Cd38^-/- mice develop a milder pristane-induced lupus disease than WT or Art2^-/- counterparts, demonstrating a new role for CD38 in promoting aberrant inflammation and lupus-like autoimmunity via a Transient Receptor Potential Melastatin 2 (TRPM2)-dependent apoptosis-driven mechanism. In this study we asked whether CD38 may play a role in the expression and function of regulatory B cells (IL-10-producing B cells or B10 cells). In pristane-treated mice the frequency of spleen CD19⁺CD1d^hiCD5⁺ B cells, which are highly enriched in B10 cells, was significantly increased in Cd38^-/- splenocytes compared to WT, while the frequency of peritoneal plasmacytoid dendritic cells (pDCs), which are major type I Interferon (IFN) producers, was greatly diminished. The low proportion of pDCs correlated with lower amounts of IFN-α in the peritoneal lavage fluids of the Cd38^-/- mice than of WT and Art2^-/- mice. Functional ex vivo assays showed increased frequencies of IL-10-producing B cells in Cd38^-/- splenocytes than in WT upon stimulation with an agonist anti-CD40 mAb. Overall these results strongly suggest that Cd38^-/- mice are better suited than WT mice to generate and expand regulatory B10 cells following the appropriate stimulation.

Modeling Macrophage Polarization and Its Effect on Cancer Treatment Success

Positive feedback loops drive immune cell polarization toward a pro-tumor phenotype that accentuates immunosuppression and tumor angiogenesis. This phenotypic switch leads to the escape of cancer cells from immune destruction. These positive feedback loops are generated by cytokines such as TGF-β, Interleukin-10 and Interleukin-4, which are responsible for the polarization of monocytes and M1 macrophages into pro-tumor M2 macrophages, and the polarization of naive helper T cells intopro-tumor Th2 cells. In this article, we present a deterministic ordinary differential equation (ODE) model that includes key cellular interactions and cytokine signaling pathways that lead to immune cell polarization in the tumor microenvironment. The model was used to simulate various cancer treatments in silico. We identified combination therapies that consist of M1 macrophages or Th1 helper cells, coupled with an anti-angiogenic treatment, that are robust with respect to immune response strength, initial tumor size and treatment resistance. We also identified IL-4 and IL-10 as the targets that should be neutralized in order to make these combination treatments robust with respect to immune cell polarization. The model simulations confirmed a hypothesis based on published experimental evidence that a polarization into the M1 and Th1 phenotypes to increase the M1-to-M2 and Th1-to-Th2 ratios plays a significant role in treatment success. Our results highlight the importance of immune cell reprogramming as a viable strategy to eradicate a highly vascularized tumor when the strength of the immune response is characteristically weak and cell polarization to the pro-tumor phenotype has occurred.

Superantigen influence in conjunction with cytokine polymorphism potentiates autoimmunity in systemic lupus erythematosus patients

Risk posed by microbial superantigens in triggering or exacerbating SLE in genetically predisposed individuals, thereby altering the response to its treatment strategies, has not been studied. Using streptococcal pyrogenic exotoxin A and staphylococcal enterotoxin B as prototype superantigens, we have demonstrated that they profoundly affect the magnitude of polyclonal T cell response, particularly CD4(+) T cells and expression of CD45RA and CD45RO, and cytokine secretion in vitro in SLE patient PBMCs. Also, reduced proportions of FoxP3 expressing CD4(+)CD25(+) T cells were detected in SLE as compared to healthy control PBMCs. Furthermore, polymorphism in IL-10 and TGF-β showed significant association with SLE in our study population. These results indicate that accumulation of superantigen-reactive T cells and cytokine polymorphism may cause disease exacerbation, relapse, or therapeutic resistance in SLE patients. Attempts to contain colonizing and/or superantigen-producing microbial agents in SLE patients in addition to careful monitoring of their therapy may be worthwhile in decreasing disease severity or preventing frequent relapses. The study suggests that superantigen interference in conjunction with cytokine polymorphism may play a role in immune dysregulation, thereby contributing to autoimmunity in SLE. Therefore, changes in T cell phenotypes and cytokine secretion might be good indicators of therapeutic efficacy in these patients.

Selective HDAC6 inhibition decreases early stage of lupus nephritis by down-regulating both innate and adaptive immune responses

We have demonstrated previously that histone deacetylase (HDAC6) expression is increased in animal models of systemic lupus erythematosus (SLE) and that inhibition of HDAC6 decreased disease. In our current studies, we tested if an orally active selective HDAC6 inhibitor would decrease disease pathogenesis in a lupus mouse model with established early disease. Additionally, we sought to delineate the cellular and molecular mechanism(s) of action of a selective HDAC6 inhibitor in SLE. We treated 20-week-old (early-disease) New Zealand Black (NZB)/White F₁ female mice with two different doses of the selective HDAC6 inhibitor (ACY-738) for 5 weeks. As the mice aged, we determined autoantibody production and cytokine levels by enzyme-linked immunosorbent assay (ELISA) and renal function by measuring proteinuria. At the termination of the study, we performed a comprehensive analysis on B cells, T cells and innate immune cells using flow cytometry and examined renal tissue for immune-mediated pathogenesis using immunohistochemistry and immunofluorescence. Our results showed a reduced germinal centre B cell response, decreased T follicular helper cells and diminished interferon (IFN)-γ production from T helper cells in splenic tissue. Additionally, we found the IFN-α-producing ability of plasmacytoid dendritic cells was decreased along with immunoglobulin isotype switching and the generation of pathogenic autoantibodies. Renal tissue showed decreased immunoglobulin deposition and reduced inflammation as judged by glomerular and interstitial inflammation. Taken together, these studies show selective HDAC6 inhibition decreased several parameters of disease pathogenesis in lupus-prone mice. The decrease was due in part to inhibition of B cell development and response.

Development of Th17-Associated Interstitial Kidney Inflammation in Lupus-Prone Mice Lacking the Gene Encoding STAT-1

OBJECTIVE

Type I interferon (IFN) signaling is a central pathogenic pathway in systemic lupus erythematosus (SLE), and therapeutics targeting type I IFN signaling are in development. Multiple proteins with overlapping functions play a role in IFN signaling, but the signaling events downstream of receptor engagement are unclear. This study was undertaken to investigate the roles of the type I and type II IFN signaling components IFN-α/β/ω receptor 2 (IFNAR-2), IFN regulatory factor 9 (IRF-9), and STAT-1 in a mouse model of SLE.

METHODS

We used immunohistochemical staining and highly multiplexed assays to characterize pathologic changes in histology, autoantibody production, cytokine/chemokine profiles, and STAT phosphorylation in order to investigate the individual roles of IFNAR-2, IRF-9, and STAT-1 in MRL/lpr mice.

RESULTS

We found that STAT-1(-/-) mice, but not IRF-9(-/-) or IFNAR-2(-/-) mice, developed interstitial nephritis characterized by infiltration with retinoic acid receptor-related orphan nuclear receptor γt-positive lymphocytes, macrophages, and eosinophils. Despite pronounced interstitial kidney disease and abnormal kidney function, STAT-1(-/-) mice had decreased proteinuria, glomerulonephritis, and autoantibody production. Phosphospecific flow cytometry revealed shunting of STAT phosphorylation from STAT-1 to STAT-3/4.

CONCLUSION

We describe unique contributions of STAT-1 to pathology in different kidney compartments in a mouse model, and provide potentially novel insight into tubulointerstitial nephritis, a poorly understood complication that predicts end-stage kidney disease in SLE patients.

Cytokine profile in childhood-onset systemic lupus erythematosus: a cross-sectional and longitudinal study

Childhood-onset systemic lupus erythematosus (cSLE) exhibits an aggressive clinical phenotype and severe complications. This could be due to a pro-inflammatory cytokine milieu. Therefore, we determined plasma levels of Th1 (IL-2, IFN-γ, TNF), Th2 (IL-4), Th17 (IL-17A, IL-6), and Treg (IL-10) cytokines in a cohort of cSLE patients and healthy controls, and we evaluated the association between these cytokines and disease activity. We conducted a cross-sectional study with 51 cSLE patients from two pediatric rheumatology services. Ten cSLE patients participated in a longitudinal follow-up study. Blood samples were collected from the same patient during active and inactive disease. Disease activity was evaluated according to SLE Disease Activity Index 2000 (SLEDAI-2K). Cytokines levels were measured by cytometric bead array technique. cSLE patients had higher IL-6 (P<0.001) and IL-10 (P<0.001) levels than healthy controls. Patients with active disease had higher IL-6 and IL-10 levels than patients with inactive disease (P=0.001 and P=0.014, respectively) and the control group (both P<0.001). IL-6 (P=0.022), IL-10 (P=0.013), and IL-17A (P=0.041) levels were significantly higher during active than inactive disease. Linear regression analysis revealed IL-6 (P=0.002, 95%CI=0.006-0.025) and IL-10 (P=0.01 95%CI=0.021-0.150) as independent factors for increased SLEDAI-2K. IL-6, IL-10, and IL-17A are candidate biomarkers for disease activity in cSLE patients. This is the first longitudinal study to support their pivotal role in the pathogenesis of the disease.

Interleukin-2-inducible T-cell kinase expression and relation to disease severity in systemic lupus erythematosus

BACKGROUND

Interleukin-2 inducible T-cell kinase (ITK) is expressed in T cells, and plays an important role in autoimmune inflammatory diseases through regulating the balance of Th17/Treg. However, its role in human systemic lupus erythematosus (SLE) remains unclear. The present study aims to measure the activation status of ITK in T cells from SLE patients and healthy controls, and identify its possible correlation to disease severity. We also discuss the serum levels of Th17, Treg related cytokines including IL-17, IL-21, IL-22, IL-10, analyzing correlation between ITK and Th17/Treg related cytokines.

METHODS

Peripheral blood samples were drawn from 42 patients with SLE and 43 healthy blood donors, and the phosphorylation of ITK protein was studied in T cells using flow cytometry. In addition, serum levels of Th17/Treg related cytokines were studied with enzyme-linked immunosorbent assay (ELISA).

RESULTS

Percentages of CD4⁺pITK⁺ T cells, CD8⁺pITK⁺ T cells were higher in SLE patients compared with controls, and were positively related to disease activity, some clinical and laboratory parameters. Percentages of CD4⁺pITK⁺ T cells, CD8⁺pITK⁺ T cells were more prominent in active SLE patients compared with less active patients. Serum levels of Th17 and Treg related cytokines were higher in patients compared with controls. CD4⁺pITK⁺ T cells were related to levels of IL-17, IL-21.

CONCLUSION

These data indicate that increased ITK expression could act as a disease activity marker and as a risk factor for involvement in SLE, but it still needs further study to confirm.

Clinical associations of IL-10 and IL-37 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the development of autoantibodies to nuclear antigens and inflammatory responses mediated by multiple cytokines. Although previous studies have determined clinical associations between SLE and the anti-inflammatory cytokines IL-10 and IL-37, their role in the disease, or their potential as biomarkers, remains unclear. We examined serum levels of IL-10 and IL-37 in a large cohort of SLE patients, with detailed longitudinal clinical data. We demonstrate a statistically significant association of serum IL-10 with disease activity, with higher levels in active compared to inactive disease. High first visit IL-10 was predictive of high subsequent disease activity; patients with IL-10 in highest quartile at first visit were 3.6 times more likely to have active disease in subsequent visits. Serum IL-37 was also higher in SLE patients compared to control, and was strongly associated with Asian ethnicity. However, IL-37 was not statistically significantly associated with disease activity. IL-37 was significantly reduced in patients with organ damage but this association was attenuated in multivariable analysis. The data suggest that IL-10, but not IL-37, may have potential as a biomarker predictive for disease activity in SLE.

Impact of CD200-Fc on dendritic cells in lupus-prone NZB/WF1 mice

Abnormal expression of CD200/CD200R1 may contribute to the immunologic abnormalities in patients with systemic lupus erythematosus (SLE). This study aimed to assess the function of CD200/CD200R1and impact of CD200-Fc on dendritic cells in lupus-prone NZB/WF1 mice. Female NZB/WF1 mice were treated with CD200-Fc or control for 4 weeks. Plasma samples were collected to measure autoantibody levels. The expression levels of CD200/CD200R1 in peripheral blood mononuclear cells (PBMCs) and splenocytes were examined. The percentage of CD200/CD200R1-positive cells in splenocytes from NZB/WF1 mice was lower than that of C57BL/6 mice (p < 0.05). The plasma level of anti-dsDNA was significantly higher in NZB/WF1 mice than C57BL/6 mice (p < 0.001). However, the anti-dsDNA levels decreased (p = 0.047) after CD200-Fc treatment. Finally, CD200-Fc reduced the levels of IL-6 (p = 0.017) and IL-10 (p = 0.03) in the dendritic cell culture supernatant. This study suggests that the immunosuppressive CD200/CD200R1 signaling pathway might be involved in the immunopathology of NZB/WF1 mice; the present results merit further exploration of agents that can modulate the CD200/CD200FR1 pathway as a therapy for human lupus.

Targeting interferon-α: a promising approach for systemic lupus erythematosus therapy

System lupus erythematosus (SLE) is an autoimmune disease with multicellular pathogeneic components.Recent studiessuggestan importantrole for interferon-a (IFN) in the immunopathogenesis of SLE. Data demonstrating a correlationbetween IFN-a and SLE disease severity range from elevated IFN-a levels in patients’serum and induction of IFN-regulated genes in peripheral blood mononuclear cells, to drug induced lupus disease in hepatitis C or cancer patients treated with recombinant IFN-a. In addition, mouse models of lupus in which the IFNR is deleted fail to develop disease manifestations. Thus, targetingIFN-a promises to be therapeuticallyefficacious for SLE.

Inhibition of SHP2 ameliorates the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a devastating multisystemic autoimmune disorder. However, the molecular mechanisms underlying its pathogenesis remain elusive. Some patients with Noonan syndrome, a congenital disorder predominantly caused by gain-of-function mutations in the protein tyrosine phosphatase SH2 domain-containing PTP (SHP2), have been shown to develop SLE, suggesting a functional correlation between phosphatase activity and systemic autoimmunity. To test this directly, we measured SHP2 activity in spleen lysates isolated from lupus-prone MRL/lpr mice and found it was markedly increased compared with that in control mice. Similar increases in SHP2 activity were seen in peripheral blood mononuclear cells isolated from lupus patients relative to healthy patients. To determine whether SHP2 alters autoimmunity and related immunopathology, we treated MRL/lpr mice with an SHP2 inhibitor and found increased life span, suppressed crescentic glomerulonephritis, reduced spleen size, and diminished skin lesions. SHP2 inhibition also reduced numbers of double-negative T cells, normalized ERK/MAPK signaling, and decreased production of IFN-γ and IL-17A/F, 2 cytokines involved in SLE-associated organ damage. Moreover, in cultured human lupus T cells, SHP2 inhibition reduced proliferation and decreased production of IFN-γ and IL-17A/F, further implicating SHP2 in lupus-associated immunopathology. Taken together, these data identify SHP2 as a critical regulator of SLE pathogenesis and suggest targeting of its activity as a potent treatment for lupus patients.

Increases of microRNA let-7e in peripheral blood mononuclear cells in Hashimoto's disease

MicroRNA (miRNA) is a family of non-coding RNAs that have important roles in various vital functions. It has been reported that let-7e, a miRNA, may be involved in the regulation of interleukin (IL)-10 production. The purpose of this study was to evaluate the role of let-7e as a regulator of IL-10 production in the pathological processes of autoimmune thyroid diseases (AITDs). We evaluated the association between let-7e expression and intracellular expression of IL-10 in the peripheral blood mononuclear cells (PBMCs) collected from 11 healthy volunteers. Then we investigated the expression levels of let-7e in the PBMCs of 50 patients with Graves' disease (GD), 42 patients with Hashimoto's disease (HD) and 28 healthy controls. We found negative correlations between the expression level of let-7e and IL-10 messengerRNA (mRNA) and between the expression level of let-7e and proportion of IL-10(+) cells in stimulated PBMCs from healthy volunteers (r = -0.44, p = 0.0267 and r = -0.49, p = 0.0166, respectively). The expression levels of let-7e were significantly increased in HD patients compared with those in GD patients and healthy volunteers (p = 0.0003 and p = 0.0011, respectively). let-7e may be associated with the pathogenesis of HD through the regulation of intracellular IL-10 expression.

Association of Interleukin-1B and Interleukin-4 Gene Variants with Autoimmune Thyroid Diseases in Tunisian Population

Autoimmune thyroid diseases (AITD) including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are complex genetic diseases. Cytokines IL-1B and IL-4 play a role in the pathogenesis of AITD. This study was conducted on Tunisian patients with GD or HT to investigate the association of IL-1B and IL-4 gene polymorphisms with the risk and the prognosis of AITD. A total of 358 healthy controls and 341 patients with AITDs (249 HT and 92 GD) were genotyped for IL-1B+3953C/T and IL-4 intron 3 VNTR polymorphisms. A significant association was found between IL-1B+3953C/T polymorphism and GD or HT, both in the dominant and additive models. The IL-1B+3953T allele was associated with GD (p = 0.0003, OR = 1.93, CI = 1.34-2.78) and HT (p = 0.009, OR = 1.43, CI = 1.09-1.88). The IL-4 VNTR polymorphism was associated only with HT risk both in additive (p = 0.03, OR = 0.31, CI = 0.11-0.86) and recessive (p = 0.03, OR = 3.04, CI = 1.13-8.17) models. No significant association was found between IL-1B+3953C/T polymorphism and change in the serum concentrations of TSH and FT4 in GD and HT patients. In HT patients, the IL-1B+3953T allele (p = 0.009, OR = 0.42, CI = 0.22-0.83) and the IL-1B+3953T/T genotype (p = 0.03, OR = 0.21, CI = 0.04-1.07) were more frequent in the absence than in the presence of an anti-TPO antibody. The proportion of HT patients with the P1P2 genotype of the IL-4 gene was significantly higher in the absence than in the presence of the anti-TPO antibody (p = 0.04, OR = 0.39, CI = 0.17-0.89). These preliminary results suggest that IL-1B and IL-4 gene polymorphisms may be associated with GD and HT susceptibility and may represent prognostic factors for predicting the severity of HT.

IL-10 Production Is Critical for Sustaining the Expansion of CD5+ B and NKT Cells and Restraining Autoantibody Production in Congenic Lupus-Prone Mice

The development and progression of systemic lupus erythematosus is mediated by the complex interaction of genetic and environmental factors. To decipher the genetics that contribute to pathogenesis and the production of pathogenic autoantibodies, our lab has focused on the generation of congenic lupus-prone mice derived from the New Zealand Black (NZB) strain. Previous work has shown that an NZB-derived chromosome 4 interval spanning 32 to 151 Mb led to expansion of CD5⁺ B and Natural Killer T (NKT) cells, and could suppress autoimmunity when crossed with a lupus-prone mouse strain. Subsequently, it was shown that CD5⁺ B cells but not NKT cells derived from these mice could suppress the development of pro-inflammatory T cells. In this paper, we aimed to further resolve the genetics that leads to expansion of these two innate-like populations through the creation of additional sub-congenic mice and to characterize the role of IL-10 in the suppression of autoimmunity through the generation of IL-10 knockout mice. We show that expansion of CD5⁺ B cells and NKT cells localizes to a chromosome 4 interval spanning 91 to 123 Mb, which is distinct from the region that mediates the majority of the suppressive phenotype. We also demonstrate that IL-10 is critical to restraining autoantibody production and surprisingly plays a vital role in supporting the expansion of innate-like populations.

The role of Bruton's tyrosine kinase in autoimmunity and implications for therapy

Bruton's tyrosine kinase (BTK) mediates B cell signaling and is also present in innate immune cells but not T cells. BTK propagates B cell receptor (BCR) responses to antigen-engagement as well as to stimulation via CD40, toll-like receptors (TLRs), Fc receptors (FCRs) and chemokine receptors. Importantly, BTK can modulate signaling, acting as a "rheostat" rather than an "on-off" switch; thus, overexpression leads to autoimmunity while decreased levels improve autoimmune disease outcomes. Autoreactive B cells depend upon BTK for survival to a greater degree than normal B cells, reflected as loss of autoantibodies with maintenance of total antibody levels when BTK is absent. This review describes contributions of BTK to immune tolerance, including studies testing BTK-inhibitors for treatment of autoimmune diseases.

The Role of the Transcription Factor Ets1 in Lupus and Other Autoimmune Diseases

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by excess B- and T-cell activation, the development of autoantibodies against self-antigens including nuclear antigens, and immune complex deposition in target organs, which triggers an inflammatory response and tissue damage. The genetic and environmental factors that contribute to the development of SLE have been studied extensively in both humans and mouse models of the disease. One of the important genetic contributions to SLE development is an alteration in the expression of the transcription factor Ets1, which regulates the functional differentiation of lymphocytes. Here, we review the genetic, biochemical, and immunological studies that have linked low levels of Ets1 to aberrant lymphocyte differentiation and to the pathogenesis of SLE.

Therapeutic potential of regulatory cytokines that target B cells

Autoreactive B cells play a crucial role in the pathogenesis of autoimmune diseases by producing auto-antibodies and presenting antigens. Regulatory cytokines that simultaneously suppress multiple pathways have the potential to control autoreactive B cells. The generally inhibitory cytokine IL-10 may have a stimulatory effect on human B-cell survival and antibody production. TGF-β family cytokines can decrease or increase antibody production and can suppress B-cell proliferation and differentiation. In contrast to TGF-β1, which induces extensive fibrosis, TGF-β3 and bone morphogenetic protein 6 (BMP-6)/BMP-7 induce non-scarring wound healing and counteract tissue fibrosis. Therefore, TGF-β3 and BMP-6/BMP-7 may be clinically applicable as therapeutic cytokines that target B cells. Recent progress in protein engineering may enable us to generate novel biologic therapies based on TGF-β family cytokines.

Evaluating the association of interleukin-10 gene promoter -592 A/C polymorphism with lupus nephritis susceptibility

Background

Interleukin-10 (IL-10) is an important immunoregulatory cytokine. There are few studies evaluating the association between IL-10 and lupus nephritis (LN). The aim of this study was to evaluate the association of IL-10 gene promoter -592 A/C with LN susceptibility.

Methods

The study was conducted on 84 patients with systemic lupus erythematosus (SLE). Patients were divided into LN group (Group I, 48 patients) and non-LN group (Group II, 36 patients). The -592 A/C polymorphisms in IL-10 promoter gene were determined by polymerase chain reaction and restriction fragment length polymorphism in both groups. IL-10 was determined by enzyme-linked immunosorbent assay. Frequencies of the genotypes were compared between LN and non-LN patients and among LN patients with different pathologic classes.

Results

There was a significant increase in serum level of IL-10 (P = 0.001) in Group I compared with Group II and significant positive correlation between serum IL-10 and SLE disease activity index (r = 0.466, P = 0.001) in Group I. There were no significant differences in the distribution of the IL-10 gene promoter -592 A/C genotypes or the allele frequencies between Groups I and II. There was no significant difference between AC/CC and AA genotypes with SLE disease activity index, proteinuria, hematuria, anti-double-stranded DNA, and IL-10 in Group I. There was no significant difference in the distribution of AC and CC genotypes among different pathologic LN classes.

Conclusion

IL-10 suggested to play a role in pathogenesis and development of LN. However, the promoter -592 A/C of IL-10 gene suggested to be not associated with serum IL-10 levels or LN susceptibility. In addition, it appears that promoter -592 A/C of IL-10 gene not associated with LN activity or the pathologic classes of LN.

Specific HDAC6 inhibition by ACY-738 reduces SLE pathogenesis in NZB/W mice

We sought to determine if a selective HDAC6 inhibitor (ACY-738) decreases disease in NZB/W mice. From 22 to 38weeks-of-age, mice were injected intraperitoneally with 5 or 20mg/kg of ACY-738, or vehicle control. Body weight and proteinuria were measured every 2weeks, while sera anti-dsDNA, Ig isotypes, and cytokine levels were measured every 4weeks. Kidney disease was determined by evaluation of sera, urine, immune complex deposition, and renal pathology. Flow cytometric analysis assessed thymic, splenic, bone marrow, and peripheral lymphocyte differentiation patterns. Our results showed HDAC6 inhibition decreased SLE disease by inhibiting immune complex-mediated glomerulonephritis, sera anti-dsDNA levels, and inflammatory cytokine production and increasing splenic Treg cells. Inhibition of HDAC6 increased the percentage of cells in the early-stage developmental fractions of both pro- and pre-B cells. These results suggest that specific HDAC6 inhibition may be able to decrease SLE disease by altering aberrant T and B cell differentiation.

Comparative Efficacies of Long-Term Serial Transplantation of Syngeneic, Allogeneic, Xenogeneic, or CTLA4Ig-Overproducing Xenogeneic Adipose Tissue-Derived Mesenchymal Stem Cells on Murine Systemic Lupus Erythematosus

Allogeneic and xenogeneic transplantation are suitable alternatives for treating patients with stem cell defects and autoimmune diseases. The purpose of this study was to compare the effects of long-term serial transplantation of adipose tissue-derived mesenchymal stem cells (ASCs) from (NZB × NZW) F1 mice (syngeneic), BALB/c mice (allogeneic), or humans (xenogeneic) on systemic lupus erythematosus (SLE). The effects of transplanting human ASCs overproducing CTLA4Ig (CTLA4Ig-hASC) were also compared. Animals were divided into five experimental groups, according to the transplanted cell type. Approximately 500,000 ASCs were administered intravenously every 2 weeks from 6 to 60 weeks of age to all mice except for the control mice, which received saline. The human ASC groups (hASC and CTLA4Ig-hASC) showed a 13-week increase in average life spans and increased survival rates and decreased blood urea nitrogen, proteinuria, and glomerular IgG deposition. The allogeneic group also showed higher survival rates compared to those of the control, up to 40, 41, 42, 43, 44, 45, 52, and 53 weeks of age. Syngeneic ASC transplantation did not accelerate the mortality of the mice. The mean life span of both the syngeneic and allogeneic groups was prolonged for 6-7 weeks. Both human ASC groups displayed increased serum interleukin-10 and interleukin-4 levels, whereas both mouse ASC groups displayed significantly increased GM-CSF and interferon-γ levels in the serum. The strongest humoral immune response was induced by xenogeneic transplantation, followed by allogeneic, CTLA4Ig-xenogeneic, and syngeneic transplantations. Long-term serial transplantation of the ASCs from various sources displayed different patterns of cytokine expression and humoral responses, but all of them increased life spans in an SLE mouse model.

Interactions of surface-expressed TLR-4 and endosomal TLR-9 accelerate lupus progression in anti-dsDNA antibody transgenic mice

The hallmark of systemic lupus erythematosus (SLE) is the presence of high levels of anti-double-stranded DNA autoantibody (anti-dsDNA) in sera. In addition, pathogen infections coincide frequently with the occurrence of lupus. Our study was designed to investigate the contribution of anti-dsDNA, extracellular and intracellular Toll-like receptors (TLRs), a family of pattern-recognition receptors for sensing invading pathogens, in the pathogenesis of lupus. Although cell surface-expressed TLR4 may promote lupus progression, intracellular nucleic acid-sensing TLR9 plays either stimulatory or protective roles in different murine lupus models. To examine the role of TLR4, TLR9, and anti-dsDNA in SLE, we generated transgenic mice carrying anti-dsDNA antibody transgene and challenged the mice with TLR4- and TLR9-agonists, lipopolysaccharides (LPS), and CpG oligodeoxynucleotide (CpG ODN1826 and 2216), respectively. Splenocytes from these mice were found to secrete higher levels of interleukin-10 (IL-10) and anti-dsDNA when treated with a combination of TLR4 and TLR9 agonists (LPS + CpG). In addition, the transgenic mice were intraperitoneally administered with CpG or combined CpG and LPS to determine whether extracellular TLR4 and intracellular TLR9 activations could affect lupus progression in vivo. It was found that serum levels of anti-dsDNA antibodies and interferon-alpha were higher in CpG + LPS-treated transgenic mice than those in non-transgenic mice. Besides, elevated levels of proteinuria, blood urine nitrogen, and immune complex depositions in kidney were found in treated transgenic mice. Anti-dsDNA and simultaneous activation of surface-expressed TLR4 and endosomal TLR9 are crucial to promote the lupus progression.

Contribution of B-1a cells to systemic lupus erythematosus in the NZM2410 mouse model

Systemic lupus erythematosus (SLE) is an autoimmune disease of complex etiology in which B cells play a central role. An expanded number of B-1a cells have been consistently associated with murine lupus, and more recently with human SLE. We have identified Cdkn2c, a gene that controls cell cycle progression, as a key regulator of B-1a cell numbers and have associated Cdkn2c deficiency with autoimmune pathology, including the production of autoantibodies and the skewing of CD4(+) T cells toward inflammatory effector functions. We review the genetic studies that have led to these findings, as well as the possible mechanisms by which B-1a cell expansion and Cdkn2c deficiency are related to SLE pathogenesis.

Circulating CXCR5+CD4+helper T cells in systemic lupus erythematosus patients share phenotypic properties with germinal center follicular helper T cells and promote antibody production

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies. Recently, a specific highly activated T helper cell subset, follicular helper T (Tfh) cell, has emerged as a key immunoregulator of germinal center (GC) formation and high-affinity antibody production. To identify the pathophysiological role of Tfh cells in SLE patients, we compared the phenotypic and functional properties of circulating Tfh-like cells in lupus patients to GC-Tfh cells, and correlated the percentage of Tfh-like cells with autoantibody production and SLE disease activity.

METHODS

Peripheral blood was collected from 29 lupus patients and 25 healthy controls. Tonsils were obtained surgically from non-SLE controls and used as a source of GC-Tfh cells. Tfh cells were defined by their signature surface markers (CXCR5, ICOS, CD57, PD-1 and BTLA) via flow cytometry. IL-21 expression levels from Tfh cells were measured by real-time PCR and intracellular staining. The function of Tfh cells was carried out by co-culture of Tfh cells and autologous B cells in vitro. IgG in the culture supernatant was detected by ELISA.

RESULTS

The frequency of circulating Tfh-like cells was significantly increased in SLE patients compared to healthy controls (p < 0.05). The Tfh-like cells not only display similar phenotypes and signature cytokines with GC-Tfh cells, but also are capable of driving B cells to differentiate into IgG-secreting plasma cells in vitro. In addition, the frequency of Tfh-like cells correlated positively with the percentage of circulating plasmablasts, levels of serum anti-dsDNA antibodies and ANA.

CONCLUSION

The accumulated circulating Tfh-like cells in lupus patients share phenotypic and functional properties with GC-Tfh cells. Tfh-like cells may serve as perpetuators in the pathogenesis of SLE by enhancing the self-reactive B cell clones to further differentiate into auto antibody-producing plasmablasts, and ultimately cause autoimmunity.

Phosphorylcholine-tuftsin compound prevents development of dextransulfate-sodium-salt induced murine colitis: implications for the treatment of human inflammatory bowel disease

Improved clinical findings of inflammatory bowel disease (IBD) upon treatment with helminthes and their ova were proven in animal models of IBD and in human clinical studies. The immunomodulatory properties of several helminthes were attributed to the phosphorylcholine (PC) molecule. We assessed the therapeutic potential of tuftsin-PC conjugate (TPC) to attenuate murine colitis. Colitis was induced by Dextransulfate-Sodium-Salt (DSS) in drinking water. TPC was given by daily oral ingestion (50 μg/0.1 ml/mouse or PBS) starting at day -2. Disease activity index (DAI) score was followed daily and histology of the colon was performed by H&E staining. Analysis of the cytokines profile in distal colon lysates was performed by immunoblot. Treatment of DSS induced colitis with TPC prevented the severity of colitis, including a reduction in the DAI score, less shortening of the colon and less inflammatory activity in histology. The immunoblot showed that the colitis preventive activity of TPC was associated with downregulation of colon pro-inflammatory IL-1β, TNFα and IL-17 cytokines expression, and enhancement of anti-inflammatory IL-10 cytokine expression. In the current study, we demonstrated that TPC treatment can prevent significantly experimental colitis induction in naïve mice. We propose the TPC as a novel potential small synthetic molecule to treat colitis.