Pharmacological inhibition of TLR9 activation blocks autoantibody production in human B cells from SLE patients

o-Vanillin binds covalently to MAL/TIRAP Lys-210 but independently inhibits TLR2

Toll-like receptor (TLR) innate immunity signalling protects against pathogens, but excessive or prolonged signalling contributes to a range of inflammatory conditions. Structural information on the TLR cytoplasmic TIR (Toll/interleukin-1 receptor) domains and the downstream adaptor proteins can help us develop inhibitors targeting this pathway. The small molecule o-vanillin has previously been reported as an inhibitor of TLR2 signalling. To study its mechanism of action, we tested its binding to the TIR domain of the TLR adaptor MAL/TIRAP (MALTIR). We show that o-vanillin binds to MALTIR and inhibits its higher-order assembly in vitro. Using NMR approaches, we show that o-vanillin forms a covalent bond with lysine 210 of MAL. We confirm in mouse and human cells that o-vanillin inhibits TLR2 but not TLR4 signalling, independently of MAL, suggesting it may covalently modify TLR2 signalling complexes directly. Reactive aldehyde-containing small molecules such as o-vanillin may target multiple proteins in the cell.

Gut microbiota from B-cell-specific TLR9-deficient NOD mice promote IL-10+ Breg cells and protect against T1D

Introduction

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing β cells. Toll-like receptor 9 (TLR9) plays a role in autoimmune diseases, and B cell-specific TLR9 deficiency delays T1D development. Gut microbiota are implicated in T1D, although the relationship is complex. However, the impact of B cell-specific deficiency of TLR9 on intestinal microbiota and the impact of altered intestinal microbiota on the development of T1D are unclear.

Objectives

This study investigated how gut microbiota and the intestinal barrier contribute to T1D development in B cell-specific TLR9-deficient NOD mice. Additionally, this study explored the role of microbiota in immune regulation and T1D onset.

Methods

The study assessed gut permeability, gene expression related to gut barrier integrity, and gut microbiota composition. Antibiotics depleted gut microbiota, and fecal samples were transferred to germ-free mice. The study also examined IL-10 production, Breg cell differentiation, and their impact on T1D development.

Results

B cell-specific TLR9-deficient NOD mice exhibited increased gut permeability and downregulated gut barrier-related gene expression. Antibiotics restored gut permeability, suggesting microbiota influence. Altered microbiota were enriched in Lachnospiraceae, known for mucin degradation. Transferring this microbiota to germ-free mice increased gut permeability and promoted IL-10-expressing Breg cells. Rag-/- mice transplanted with fecal samples from Tlr9 fl/fl Cd19-Cre+ mice showed delayed diabetes onset, indicating microbiota's impact.

Conclusion

B cell-specific TLR9 deficiency alters gut microbiota, increasing gut permeability and promoting IL-10-expressing Breg cells, which delay T1D. This study uncovers a link between TLR9, gut microbiota, and immune regulation in T1D, with implications for microbiota-targeted T1D therapies.

Harnessing anti-inflammatory pathways and macrophage nano delivery to treat inflammatory and fibrotic disorders

Targeting specific organs and cell types using nanotechnology and sophisticated delivery methods has been at the forefront of applicative biomedical sciences lately. Macrophages are an appealing target for immunomodulation by nanodelivery as they are heavily involved in various aspects of many diseases and are highly plastic in their nature. Their continuum of functional "polarization" states has been a research focus for many years yielding a profound understanding of various aspects of these cells. The ability of monocyte-derived macrophages to metamorphose from pro-inflammatory to reparative and consequently to pro-resolving effectors has raised significant interest in its therapeutic potential. Here, we briefly survey macrophages' ontogeny and various polarization phenotypes, highlighting their function in the inflammation-resolution shift. We review their inducing mediators, signaling pathways, and biological programs with emphasis on the nucleic acid sensing-IFN-I axis. We also portray the polarization spectrum of macrophages and the characteristics of their transition between different subtypes. Finally, we highlighted different current drug delivery methods for targeting macrophages with emphasis on nanotargeting that might lead to breakthroughs in the treatment of wound healing, bone regeneration, autoimmune, and fibrotic diseases.

Targeting MyD88: Therapeutic mechanisms and potential applications of the specific inhibitor ST2825

BACKGROUND

Myeloid differentiation factor-88 (MyD88) is a crucial adapter protein that coordinates the innate immune response and establishes an adaptive immune response. The interaction of the Toll/Interleukin-1 receptor (IL-1R) superfamily with MyD88 triggers the activation of various signalling pathways such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), promoting the production of a variety of immune and inflammatory mediators and potentially driving the development of a variety of diseases.

OBJECTIVE

This article will explore the therapeutic potential and mechanism of the MyD88-specific inhibitor ST2825 and describe its use in the treatment of several diseases. We envision future research and clinical applications of ST2825 to provide new ideas for the development of anti-inflammatory drugs and disease-specific drugs to open new horizons for the prevention and treatment of related inflammatory diseases.

MATERIALS AND METHODS

This review analysed relevant literature in PubMed and other databases. All relevant studies on MyD88 inhibitors and ST2825 that were published in the last 20 years were used as screening criteria. These studies looked at the development and improvement of MyD88 inhibitors and ST2825.

RESULTS

Recent evidence using the small-molecule inhibitor of ST2825 has suggested that blocking MyD88 activity can be used to treat diseases such as neuroinflammation, inflammatory diseases such as acute liver/kidney injury, or autoimmune diseases such as systemic lupus erythematosus and can affect transplantation immunity. In addition, ST2825 has potential therapeutic value in B-cell lymphoma with the MyD88 L265P mutation.

CONCLUSION

Targeting MyD88 is a novel therapeutic strategy, and scientific research is presently focused on the development of MyD88 inhibitors. The peptidomimetic compound ST2825 is a widely studied small-molecule inhibitor of MyD88. Thus, ST2825 may be a potential therapeutic small-molecule agent for modulating host immune regulation in inflammatory diseases and inflammatory therapy.

Role of Semaphorin 3A in Kidney Development and Diseases

Kidney diseases are worldwide public health problems affecting millions of people. However, there are still limited therapeutic options against kidney diseases. Semaphorin 3A (SEMA3A) is a secreted and membrane-associated protein, which regulates diverse functions, including immune regulation, cell survival, migration and angiogenesis, thus involving in the several pathogeneses of diseases, including eyes and neurons, as well as kidneys. SEMA3A is expressed in podocytes and tubular cells in the normal adult kidney, and recent evidence has revealed that excess SEMA3A expression and the subsequent signaling pathway aggravate kidney injury in a variety of kidney diseases, including nephrotic syndrome, diabetic nephropathy, acute kidney injury, and chronic kidney disease. In addition, several reports have demonstrated that the inhibition of SEMA3A ameliorated kidney injury via a reduction in cell apoptosis, fibrosis and inflammation; thus, SEMA3A may be a potential therapeutic target for kidney diseases. In this review article, we summarized the current knowledge regarding the role of SEMA3A in kidney pathophysiology and their potential use in kidney diseases.

Application and prospect of targeting innate immune sensors in the treatment of autoimmune diseases

Dysregulation of auto-reactive T cells and autoantibody-producing B cells and excessive inflammation are responsible for the occurrence and development of autoimmune diseases. The suppression of autoreactive T cell activation and autoantibody production, as well as inhibition of inflammatory cytokine production have been utilized to ameliorate autoimmune disease symptoms. However, the existing treatment strategies are not sufficient to cure autoimmune diseases since patients can quickly suffer a relapse following the end of treatments. Pattern recognition receptors (PRRs), including Toll-like receptors (TLRs), Nod-like receptors (NLRs), RIG-I like receptors (RLRs), C-type lectin receptors (CLRs) and various nucleic acid sensors, are expressed in both innate and adaptive immune cells and are involved in the development of autoimmune diseases. Here, we have summarized advances of PRRs signaling pathways, association between PRRs and autoimmune diseases, application of inhibitors targeting PRRs and the corresponding signaling molecules relevant to strategies targeting autoimmune diseases. This review emphasizes the roles of different PRRs in activating both innate and adaptive immunity, which can coordinate to trigger autoimmune responses. The review may also prompt the formulation of novel ideas for developing therapeutic strategies against autoimmune diseases by targeting PRRs-related signals.

Targeting MyD88 Downregulates Inflammatory Mediators and Pathogenic Processes in PBMC From DMARDs-Naïve Rheumatoid Arthritis Patients

MyD88-dependent intracellular signalling cascades and subsequently NF-kappaB-mediated transcription lead to the dynamic inflammatory processes underlying the pathogenesis of rheumatoid arthritis (RA) and related autoimmune diseases. This study aimed to identify the effect of the MyD88 dimerization inhibitor, ST2825, as a modulator of pathogenic gene expression signatures and systemic inflammation in disease-modifying antirheumatic drugs (DMARDs)-naïve RA patients. We analyzed bulk RNA-seq from peripheral blood mononuclear cells (PBMC) in DMARDs-naïve RA patients after stimulation with LPS and IL-1β. The transcriptional profiles of ST2825-treated PBMC were analyzed to identify its therapeutic potential. Ingenuity Pathway Analysis was implemented to identify downregulated pathogenic processes. Our analysis revealed 631 differentially expressed genes between DMARDs-naïve RA patients before and after ST2825 treatment. ST2825-treated RA PBMC exhibited a gene expression signature similar to that of healthy controls PBMC by downregulating the expression of proinflammatory cytokines, chemokines and matrix metalloproteases. In addition, B cell receptor, IL-17 and IL-15 signalling were critically downregulated pathways by ST2825. Furthermore, we identified eight genes (MMP9, CXCL9, MZB1, FUT7, TGM2, IGLV1-51, LINC01010, and CDK1) involved in pathogenic processes that ST2825 can potentially inhibit in distinct cell types within the RA synovium. Overall, our findings indicate that targeting MyD88 effectively downregulates systemic inflammatory mediators and modulates the pathogenic processes in PBMC from DMARDs-naïve RA patients. ST2825 could also potentially inhibit upregulated genes in the RA synovium, preventing synovitis and joint degeneration.

Circulating mitochondrial DNA copy numbers represent a sensitive marker for diagnosis and monitoring of disease activity in systemic lupus erythematosus

OBJECTIVES

Cell-free DNA is involved in the pathogenesis of systemic lupus erythematosus (SLE) but the clinical value of cell-free DNA measurements in SLE is unknown. Our aim was therefore to examine the utility of mitochondrial (mt) DNA and nuclear (n) DNA quantification in SLE.

METHODS

EDTA plasma was drawn from 103 consecutive patients with SLE and from 56 healthy blood donors. mtDNA and nDNA copy numbers were quantified by PCR from cell-free plasma. Clinical parameters were recorded prospectively.

RESULTS

Circulating mtDNA copy numbers were increased 8.8-fold in the plasma of patients with SLE (median 6.6×10⁷ /mL) compared with controls (median 7.6×10⁶ /mL, p<0.0001). Among all 159 individuals, a cut-off set at 1.8×10⁷ mtDNA copies in a receiver operated curve identified patients with SLE with 87.4% sensitivity and 94.6% specificity; the area under the curve was 0.95 (p<0.0001). mtDNA levels were independent of age or gender, but correlated with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) on multivariable analysis (p=0.004). Conversely, SLEDAI was associated with prednisone dose (p<0.001), anti-double stranded DNA-titres (p=0.003) and mtDNA levels (p=0.005), but not nDNA copy numbers. In 33 patients with SLE with available follow-up, the changes of mtDNA, but not those of nDNA concentrations, robustly correlated with the evolution of the SLEDAI (r=0.55, p=0.001).

CONCLUSIONS

Circulating mtDNA unlike nDNA molecules are markedly increased in SLE plasma. Regardless of disease activity, circulating mtDNA levels distinguish patients with SLE from healthy controls with high sensitivity and represent an independent marker of SLE activity.

The Immunomodulatory Effect of the Gut Microbiota in Kidney Disease

The human gut microbiota is a complex cluster composed of 100 trillion microorganisms, which holds a symbiotic relationship with the host under normal circumstances. Intestinal flora can facilitate the treatment of human metabolic dysfunctions and interact with the intestinal tract, which could influence intestinal tolerance, immunity, and sensitivity to inflammation. In recent years, significant interests have evolved on the association of intestinal microbiota and kidney diseases within the academic circle. Abnormal changes in intestinal microbiota, known as dysbiosis, can affect the integrity of the intestinal barrier, resulting in the bacterial translocation, production, and accumulation of dysbiotic gut-derived metabolites, such as urea, indoxyl sulfate (IS), and p-cresyl sulfate (PCS). These processes lead to the abnormal activation of immune cells; overproduction of antibodies, immune complexes, and inflammatory factors; and inflammatory cell infiltration that can directly or indirectly cause damage to the renal parenchyma. The aim of this review is to summarize the role of intestinal flora in the development and progression of several renal diseases, such as lupus nephritis, chronic kidney disease, diabetic nephropathy, and renal ischemia-reperfusion injury. Further research on these mechanisms should provide insights into the therapeutic potential of regulating intestinal flora and intervening related molecular targets for the abovementioned nephropathy.

Nucleic Acid Sensors as Therapeutic Targets for Human Disease

Innate immune sensors that detect nucleic acids are attractive targets for therapeutic intervention because of their diverse roles in many disease processes. In detecting RNA and DNA from either self or non-self, nucleic acid sensors mediate the pathogenesis of many autoimmune and inflammatory conditions. Despite promising pre-clinical data and investigational use in the clinic, relatively few drugs targeting nucleic acid sensors are approved for therapeutic use. Nevertheless, there is growing appreciation for the untapped potential of nucleic acid sensors as therapeutic targets, driven by the need for better therapies for cancer, infectious diseases, and autoimmune disorders. This review highlights the diverse mechanisms by which nucleic acid sensors are activated and exert their biological effects in the context of various disease settings. We discuss current therapeutic strategies utilizing agonists and antagonists targeting nucleic acid sensors to treat infectious disease, cancer, and autoimmune and inflammatory disorders.

TLR9 Deficiency in B Cells Promotes Immune Tolerance via Interleukin-10 in a Type 1 Diabetes Mouse Model

Toll-like receptor 9 (TLR9) is highly expressed in B cells, and B cells are important in the pathogenesis of type 1 diabetes (T1D) development. However, the intrinsic effect of TLR9 in B cells on β-cell autoimmunity is not known. To fill this knowledge gap, we generated NOD mice with a B-cell-specific deficiency of TLR9 (TLR9^fl/fl/CD19-Cre+ NOD). The B-cell-specific deletion of TLR9 resulted in near-complete protection from T1D development. Diabetes protection was accompanied by an increased proportion of interleukin-10 (IL-10)-producing B cells. We also found that TLR9-deficient B cells were hyporesponsive to both innate and adaptive immune stimuli. This suggested that TLR9 in B cells modulates T1D susceptibility in NOD mice by changing the frequency and function of IL-10-producing B cells. Molecular analysis revealed a network of TLR9 with matrix metalloproteinases, tissue inhibitor of metalloproteinase-1, and CD40, all of which are interconnected with IL-10. Our study has highlighted an important connection of an innate immune molecule in B cells to the immunopathogenesis of T1D. Thus, targeting the TLR9 pathway, specifically in B cells, may provide a novel therapeutic strategy for T1D treatment.

Interferon-directed therapies for the treatment of systemic lupus erythematosus: a critical update

The interferon (IFN) pathway, especially type I IFN, plays a critical role in the immunopathogenesis of systemic lupus erythematosus (SLE). We have gained significant insights into this pathway over the past two decades, including a better understanding of the key mediators of inflammation upstream and downstream of type I IFN. This has led to the identification of multiple potential targets for the treatment of SLE, for which a significant unmet need remains due to the failure of many patients to adequately respond to standard-of-care medications. Unfortunately, most new therapies in SLE have disappointed in preclinical or clinical trials to date, including a number that target type I IFN. Nevertheless, several IFN-directed therapies aimed at specific steps within this immunologic pathway have recently shown promise, and additional agents are in the treatment pipeline. In this review, we focus on the results of key therapeutic studies targeting the type I IFN pathway and discuss the future state of IFN-blockade in SLE.

Toll-like Receptors as Potential Therapeutic Targets in Kidney Diseases

Toll-like Receptors (TLRs) are members of pattern recognition receptors and serve a pivotal role in host immunity. TLRs response to pathogen-associated molecular patterns encoded by pathogens or damage-associated molecular patterns released by dying cells, initiating an inflammatory cascade, where both beneficial and detrimental effects can be exerted. Accumulated evidence has revealed that TLRs are closely associated with various kidney diseases but their roles are still not well understood. This review updated evidence on the roles of TLRs in the pathogenesis of kidney diseases including urinary tract infection, glomerulonephritis, acute kidney injury, transplant allograft dysfunction and chronic kidney diseases.

Downregulation of Inflammatory Cytokine Release from IL-1β and LPS-Stimulated PBMC Orchestrated by ST2825, a MyD88 Dimerisation Inhibitor

The inflammatory process implicates homeostasis disruption and increased production of inflammatory mediators. Myeloid differentiation primary response 88 (MyD88) is an essential protein recruited after lipopolysaccharide (LPS) and interleukin (IL)-1β stimulation, a process that converges in nuclear factor kappa B (NF-κB) activation, as well as a transcription of several genes of both pro- and anti-inflammatory cytokines. The inhibition of MyD88 has shown efficacy by decrease inflammatory response, and has demonstrated potential application as a therapeutic target in chronic diseases. In this study, we investigate the effect of MyD88 dimerisation inhibitor ST2825 on cytokine production from rhIL-1β and LPS-stimulated peripheral blood mononuclear cells (PBMC) from healthy blood donors (HBD). ST2825 significantly downregulates the production of IFN-γ, IL-6, IL-12, IL-2, IL-15, IL-7, VEGF, IL-1Ra, IL-4, IL-5, IL-13 and IL-9 (p < 0.05) in LPS-stimulated PBMC. Moreover, ST2825 had a relatively low impact on IL-1β signalling pathway inhibition, showing that only a few specific cytokines, such as IFN-γ and IL-1Ra, are inhibited in rhIL-1β-stimulated PBMC (p < 0.01). In conclusion, MyD88 dimerisation inhibitor ST2825 showed high efficacy by inhibiting pro- and anti-inflammatory cytokine production in LPS-stimulated PBMC. Moreover, although rhIL-1β induced a sustained cytokine production (p < 0.05), ST2825 did not show a significant effect in the secretion of neither pro- nor anti-inflammatory cytokines in rhIL-1β-stimulated PBMC.

Modulation of the Innate Immune Response by Targeting Toll-like Receptors: A Perspective on Their Agonists and Antagonists

Toll-like receptors (TLRs) are a class of proteins that recognize pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs), and they are involved in the regulation of innate immune system. These transmembrane receptors, localized at the cellular or endosomal membrane, trigger inflammatory processes through either myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling pathways. In the last decades, extensive research has been performed on TLR modulators and their therapeutic implication under several pathological conditions, spanning from infections to cancer, from metabolic disorders to neurodegeneration and autoimmune diseases. This Perspective will highlight the recent discoveries in this field, emphasizing the role of TLRs in different diseases and the therapeutic effect of their natural and synthetic modulators, and it will discuss insights for the future exploitation of TLR modulators in human health.

Anti-CXCL4 Antibody Reactivity Is Present in Systemic Sclerosis (SSc) and Correlates with the SSc Type I Interferon Signature

Systemic sclerosis (SSc) is characterized by skin/internal organ fibrosis, vasculopathy and autoimmunity. Chemokine (C-X-C motif) ligand 4 (CXCL4) is an SSc biomarker, predicting unfavorable prognosis and lung fibrosis. CXCL4 binds DNA/RNA and favors interferon (IFN)-α production by plasmacytoid dendritic cells (pDCs), contributing to the type I IFN (IFN-I) signature in SSc patients. However, whether CXCL4 is an autoantigen in SSc is unknown. Here, we show that at least half of SSc patients show consistent antibody reactivity to CXCL4. T-cell proliferation to CXCL4, tested in a limited number of patients, correlates with anti-CXCL4 antibody reactivity. Antibodies to CXCL4 mostly correlate with circulating IFN-α levels and are significantly higher in patients with lung fibrosis in two independent SSc cohorts. Antibodies to CXCL4 implement the CXCL4-DNA complex's effect on IFN-α production by pDCs; CXCL4-DNA/RNA complexes stimulate purified human B-cells to become antibody-secreting plasma cells in vitro. These data indicate that CXCL4 is indeed an autoantigen in SSc and suggest that CXCL4, and CXCL4-specific autoantibodies, can fuel a harmful loop: CXCL4-DNA/RNA complexes induce IFN-α in pDCs and direct B-cell stimulation, including the secretion of anti-CXCL4 antibodies. Anti-CXCL4 antibodies may further increase pDC stimulation and IFN-α release in vivo, creating a vicious cycle which sustains the SSc IFN-I signature and general inflammation.

B Cell Abnormalities in Systemic Lupus Erythematosus and Lupus Nephritis-Role in Pathogenesis and Effect of Immunosuppressive Treatments

Abnormalities in B cells play pivotal roles in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). Breach in central and peripheral tolerance mechanisms generates autoreactive B cells which contribute to the pathogenesis of SLE and LN. Dysregulation of B cell transcription factors, cytokines and B cell-T cell interaction can result in aberrant B cell maturation and autoantibody production. These immunological abnormalities also lead to perturbations in circulating and infiltrating B cells in SLE and LN patients. Conventional and novel immunosuppressive medications confer differential effects on B cells which have important clinical implications. While cyclophosphamide and mycophenolate mofetil (MMF) showed comparable clinical efficacy in active LN, MMF induction was associated with earlier reduction in circulating plasmablasts and plasma cells. Accumulating evidence suggests that MMF maintenance is associated with lower risk of disease relapse than azathioprine, which may be explained by its more potent and selective suppression of B cell proliferation. Novel therapeutic approaches targeting the B cell repertoire include B cell depletion with monoclonal antibodies binding to cell surface markers, inhibition of B cell cytokines, and modulation of costimulatory signals in B cell-T cell interaction. These biologics, despite showing improvements in serological parameters and proteinuria, did not achieve primary endpoints when used as add-on therapy to standard treatments in active LN patients. Other emerging treatments such as calcineurin inhibitors, mammalian target of rapamycin inhibitors and proteasome inhibitors also show distinct inhibitory effects on the B cell repertoire. Advancement in the knowledge on B cell biology has fueled the development of new therapeutic strategies in SLE and LN. Modification in background treatments, study endpoints and selective recruitment of subjects showing aberrant B cells or its signaling pathways when designing future clinical trials may better elucidate the roles of these novel therapies for SLE and LN patients.

Induction of brain-infiltrating T-bet-expressing B cells in multiple sclerosis

Objective

Results from anti‐CD20 therapies demonstrate that B‐ and T‐cell interaction is a major driver of multiple sclerosis (MS). The local presence of B‐cell follicle‐like structures and oligoclonal bands in MS patients indicates that certain B cells infiltrate the central nervous system (CNS) to mediate pathology. Which peripheral triggers underlie the development of CNS‐infiltrating B cells is not fully understood.

Methods

Ex vivo flow cytometry was used to assess chemokine receptor profiles of B cells in blood, cerebrospinal fluid, meningeal, and brain tissues of MS patients (n = 10). Similar analyses were performed for distinct memory subsets in the blood of untreated and natalizumab‐treated MS patients (n = 38). To assess T‐bet(CXCR3)⁺ B‐cell differentiation, we cultured B cells from MS patients (n = 21) and healthy individuals (n = 34) under T helper 1‐ and TLR9‐inducing conditions. Their CNS transmigration capacity was confirmed using brain endothelial monolayers.

Results

CXC chemokine receptor 3 (CXCR3)‐expressing B cells were enriched in different CNS compartments of MS patients. Treatment with the clinically effective drug natalizumab prevented the recruitment of CXCR3^high IgG1⁺ subsets, corresponding to their increased ability to cross CNS barriers in vitro. Blocking of interferon‐γ (IFNγ) reduced the transmigration potential and antigen‐presenting function of these cells. IFNγ‐induced B cells from MS patients showed increased T‐bet expression and plasmablast development. Additional TLR9 triggering further upregulated T‐bet and CXCR3, and was essential for IgG1 switching.

Interpretation

This study demonstrates that T‐bet^high IgG1⁺ B cells are triggered by IFNγ and TLR9 signals, likely contributing to enhanced CXCR3‐mediated recruitment and local reactivity in the CNS of MS patients. ANN NEUROL 2019;86:264–278

Small-molecule inhibitors and the salivary gland epithelium in Sjögren's syndrome

INTRODUCTION

The salivary gland (SG) in primary Sjögren's syndrome (pSS) is characterized by its lack of function (hyposalivation) and lymphocytic invasion. Small-molecule inhibitors (SMIs) are a new class of drugs, whose diminutive size permits diffusion into cells. SMIs targeting components of the immune system are eagerly being trialed for their potential therapeutic utility in pSS. Neglected until now, however, is a discussion of the potential effects of SMIs on the SG epithelium.

AREAS COVERED

We begin by reminding the reader of the SG epithelial compartment, its complicity in inflammatory milieu formation in pSS, and categories of SMIs which merit attention. We discuss each SMI category, including pre-clinical data concerning pSS and likely consequences of their application on the SG epithelium.

EXPERT OPINION

Recovery of saliva production in pSS requires restoring the function of the SG epithelium, not solely on inflammation resolution. Many SMIs, for example, those blocking JAK-STAT signaling, interfere with critical epithelial cell pathways, most notably EGF signaling. If the effect of SMIs on SG epithelium is ignored, recovery of SG function will be challenging. We predict that NFκB signaling blockade will impart the least SG epithelium damage whilst reducing inflammation and facilitating recovery from hyposalivation in pSS.

Potential Chronotherapeutic Optimization of Antimalarials in Systemic Lupus Erythematosus: Is Toll-Like Receptor 9 Expression Dependent on the Circadian Cycle in Humans?

Toll-like receptor 9 (TLR9) belongs to the group of endosomal receptors of the innate immune system with the ability to recognize hypomethylated CpG sequences from DNA. There is scarce information about TLR9 expression and its association with the circadian cycle (CC). Different patterns of TLR9 expression are regulated by the CC in mice, with an elevated expression at Zeitgeber time 19 (1:00 a.m.); nevertheless, we still need to corroborate this in humans. In systemic lupus erythematosus (SLE), the inhibitory effect of chloroquine (CQ) on TLR9 is limited. TLR9 activation has been associated with the presence of some autoantibodies: anti-Sm/RNP, anti-histone, anti-Ro, anti-La, and anti-double-stranded DNA. Treatment with CQ for SLE has been proven to be useful, in part by interfering with HLA-antigen coupling and with TLR9 ligand recognition. Studies have shown that TLR9 inhibitors such as antimalarial drugs are able to mask TLR9-binding sites on nucleic acids. The data presented here provide the basic information that could be useful for other clinical researchers to design studies that will have an impact in achieving a chronotherapeutic effect by defining the ideal time for CQ administration in SLE patients, consequently reducing the pathological effects that follow the activation of TLR9.

Toll-like receptors in lupus nephritis

The pathogenesis of systemic autoimmune diseases such as systemic lupus erythematosus (SLE) is based on the loss of self-tolerance against ubiquitous autoantigens involving all mechanisms of adaptive immunity. However, data accumulating over the last decade imply an important role also for numerous elements of innate immunity, namely the Toll-like receptors in the pathogenesis of SLE. Here we discuss their role in the most common organ complication of SLE, i.e. lupus nephritis. We summarize experimental and clinical data on the expression and functional contribution of the Toll-like receptors in immune complex glomerulonephritis, and intrarenal inflammation. Based on these discoveries Toll-like receptors are evolving as therapeutic targets for the treatment of SLE and lupus nephritis.

Targeting Suppressive Oligonucleotide to Lymph Nodes Inhibits Toll-like Receptor-9-Mediated Activation of Adaptive Immunity

PURPOSE

This paper aims to investigate the immunoinhibitory properties of a lymph nodes-targeting suppressive oligonucleotide (ODN) for the potential treatment of autoimmune diseases or chronic inflammation.

METHODS

Synthetic suppressive ODN engineered with an albumin-binding diacyl lipid at the 5'-terminal (lipo-ODN) was synthesized. In vitro and in vivo experiments were designed to compare the immune suppressive properties of lipo-ODN and unmodified ODN. Cellular uptake and distribution, inhibition of Toll-like receptor (TLR) activation, lymph nodes (LN) draining, and the suppression of antigen-specific immune responses in an ovalbumin protein model was investigated.

RESULTS

Compared to unmodified ODN, lipid functionalized suppressive ODN demonstrated enhanced cellular uptake and TLR-9 specific immune suppression in TLR reporter cells. Additionally, injection of a low dose of lipid-modified suppressive ODN, but not the unconjugated ODN, accumulated in the draining LNs and exhibited potent inhibition of antigen-specific CD8⁺ T cell and B cell responses in vivo.

CONCLUSIONS

Targeting suppressive ODN to antigen presenting cells (APCs) in the local LNs is an effective approach to amplify the immune modulation mediated by ODN containing repetitive TTAGGG motif. This approach might be broadly applicable to target molecular adjuvants to the key immune cells in the LNs draining from disease site, providing a simple strategy to improve the efficacy of many molecular immune modulators.

TLRs/NLRs: Shaping the landscape of host immunity

Innate immune system provides the first line of defense against pathogenic organisms. It has a varied and large collection of molecules known as pattern recognition receptors (PRRs) which can tackle the pathogens promptly and effectively. Toll-like receptors (TLRs) and NOD-like receptors (NLRs) are members of the PRR family that recognize pathogen associated molecular patterns (PAMPs) and play pivotal roles to mediate defense against infections from bacteria, fungi, virus and various other pathogens. In this review, we discuss the critical roles of TLRs and NLRs in the regulation of host immune-effector functions such as cytokine production, phagosome-lysosome fusion, inflammasome activation, autophagy, antigen presentation, and B and T cell immune responses that are known to be essential for mounting a protective immune response against the pathogens. This review may be helpful to design TLRs/NLRs based immunotherapeutics to control various infections and pathophysiological disorders.

Inhibition of myeloid differentiation primary response protein 88 provides neuroprotection in early brain injury following experimental subarachnoid hemorrhage

Accumulating of evidence suggests that activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) exacerbates early brain injury (EBI) following subarachnoid hemorrhage (SAH) by provoking pro-inflammatory and pro-apoptotic signaling. Myeloid differentiation primary response protein 88 (MyD88) is an endogenous adaptor protein in the toll-like receptors (TLRs) and interleukin (IL) -1β family signaling pathways and acts as a bottle neck in the NF-κB and MAPK pathways. Here, we used ST2825, a selective inhibitor of MyD88, to clarify whether inhibiting MyD88 could provide neuroprotection in EBI following SAH. Our results showed that the expression of MyD88 was markedly increased at 24 h post SAH. Intracerebroventricular injection of ST2825 significantly reduced the expression of MyD88 at 24 h post SAH. Involvement of MAPKs and NF-κB signaling pathways was revealed that ST2825 inhibited SAH-induced phosphorylation of TAK1, p38 and JNK, the nuclear translocation of NF-κB p65, and degradation of IκBα. Further, ST2825 administration diminished the SAH-induced inflammatory response and apoptosis. As a result, SAH-induced EBI was alleviated and neurological deficits caused by SAH were reversed. Our findings suggest that MyD88 inhibition confers marked neuroprotection against EBI following SAH. Therefore, MyD88 might be a promising new molecular target for the treatment of SAH.

Targeting interferons and their pathways in systemic lupus erythematosus

Significant advances in the understanding of the molecular basis of innate immunity have led to the identification of interferons (IFNs), particularly IFN-α, as central mediators in the pathogenesis of Systemic Lupus Erythematosus. Therefore, targeting of IFNs and of their downstream pathways has emerged as important developments for novel drug research in SLE. Based on this, several specific interferon blocking strategies using anti-IFN-α antibodies, anti-type I interferon receptor antibodies, Interferon-α-kinoid, or anti-IFN-γ antibodies have all been assessed in recent clinical trials. Alternative strategies targeting the plasmacytoid dendritic cells (pDCs), Toll-Like Receptors (TLRs)-7/9 or their downstream pathways such as the myeloid differentiation primary-response protein 88 (MYD88), spleen tyrosine kinase (Syk), Janus-kinases (JAKs), interleukin-1 receptor-associated kinase 4 (IRAK4), or the Tyrosine Kinase 2 (TYK2) are also investigated actively in SLE, at more preliminary clinical development stages, except for JAK inhibitors which have reached phase 2 studies. In a near future, in-depth and personalized functional characterization of IFN pathways may provide further guidance for the selection of the most relevant therapeutic strategy in SLE, tailored at the patient-level.

Innate immunity in Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease of exocrine tissue that primarily affects women. Although patients typically experience xerostomia and xerophthalmia, numerous systemic disease manifestations are seen. Innate immune hyperactivity is integral to many autoimmune diseases, including SS. Results from SS mouse models suggest that innate immune dysregulation drives disease and this is a seminal event in SS pathogenesis. Findings in SS patients corroborate those in mouse models, as innate immune cells and pathways are dysregulated both in exocrine tissue and in peripheral blood. We will review the role of the innate immune system in SS pathogenesis. We will discuss the etiology of SS with an emphasis on innate immune dysfunction. Moreover, we will review the innate cells that mediate inflammation in SS, the pathways implicated in disease, and the potential mechanisms governing their dysregulation. Finally, we will discuss emerging therapeutic approaches to target dysregulated innate immune signaling in SS.

Natural Modulators of Endosomal Toll-Like Receptor-Mediated Psoriatic Skin Inflammation

Psoriasis is a chronic inflammatory autoimmune disease that can be initiated by excessive activation of endosomal toll-like receptors (TLRs), particularly TLR7, TLR8, and TLR9. Therefore, inhibitors of endosomal TLR activation are being investigated for their ability to treat this disease. The currently approved biological drugs adalimumab, etanercept, infliximab, ustekinumab, ixekizumab, and secukizumab are antibodies against effector cytokines that participate in the initiation and development of psoriasis. Several immune modulatory oligonucleotides and small molecular weight compounds, including IMO-3100, IMO-8400, and CPG-52364, that block the interaction between endosomal TLRs and their ligands are under clinical investigation for their effectiveness in the treatment of psoriasis. In addition, several chemical compounds, including AS-2444697, PF-05387252, PF-05388169, PF-06650833, ML120B, and PHA-408, can inhibit TLR signaling. Although these compounds have demonstrated anti-inflammatory activity in animal models, their therapeutic potential for the treatment of psoriasis has not yet been tested. Recent studies demonstrated that natural compounds derived from plants, fungi, and bacteria, including mustard seed, Antrodia cinnamomea extract, curcumin, resveratrol, thiostrepton, azithromycin, and andrographolide, inhibited psoriasis-like inflammation induced by the TLR7 agonist imiquimod in animal models. These natural modulators employ different mechanisms to inhibit endosomal TLR activation and are administered via different routes. Therefore, they represent candidate psoriasis drugs and might lead to the development of new treatment options.

Inhibition of Toll-Like Receptor Signaling as a Promising Therapy for Inflammatory Diseases: A Journey from Molecular to Nano Therapeutics

The recognition of invading pathogens and endogenous molecules from damaged tissues by toll-like receptors (TLRs) triggers protective self-defense mechanisms. However, excessive TLR activation disrupts the immune homeostasis by sustained pro-inflammatory cytokines and chemokines production and consequently contributes to the development of many inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE), infection-associated sepsis, atherosclerosis, and asthma. Therefore, inhibitors/antagonists targeting TLR signals may be beneficial to treat these disorders. In this article, we first briefly summarize the pathophysiological role of TLRs in the inflammatory diseases. We then focus on reviewing the current knowledge in both preclinical and clinical studies of various TLR antagonists/inhibitors for the prevention and treatment of inflammatory diseases. These compounds range from conventional small molecules to therapeutic biologics and nanodevices. In particular, nanodevices are emerging as a new class of potent TLR inhibitors for their unique properties in desired bio-distribution, sustained circulation, and preferred pharmacodynamic and pharmacokinetic profiles. More interestingly, the inhibitory activity of these nanodevices can be regulated through precise nano-functionalization, making them the next generation therapeutics or “nano-drugs.” Although, significant efforts have been made in developing different kinds of new TLR inhibitors/antagonists, only limited numbers of them have undergone clinical trials, and none have been approved for clinical uses to date. Nevertheless, these findings and continuous studies of TLR inhibition highlight the pharmacological regulation of TLR signaling, especially on multiple TLR pathways, as future promising therapeutic strategy for various inflammatory and autoimmune diseases.

Neutrophils, Dendritic Cells, Toll-Like Receptors, and Interferon-α in Lupus Nephritis

Finding better treatments for lupus nephritis requires an understanding of the pathogenesis of the causative systemic disease, how this leads to kidney disease, and how lupus nephritis progresses to end-stage kidney disease. Here, we provide a brief conceptual overview on the related pathomechanisms. As a main focus we discuss in detail the roles of neutrophils, dendritic cells, Toll-like receptors, and interferon-α in the pathogenesis of lupus nephritis by separately reviewing their roles in extrarenal systemic autoimmunity and in intrarenal inflammation and immunopathology.

Toll-like receptor activation in the pathogenesis of lupus nephritis

The pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis is complex but no longer enigmatic. Much progress has been made to on the polygenetic origin of lupus in identifying gene variants that permit the loss of tolerance against nuclear autoantigens. Along the same line in about 50% of lupus patients additional genetic weaknesses promote immune complex glomerulonephritis and filtration barrier dysfunction. Here we briefly summarize the pathogenesis of SLE with a focus on loss of tolerance and the role of toll-like receptors in the "pseudo"-antiviral immunity concept of systemic lupus. In addition, we discuss the local role of Toll-like receptors in intrarenal inflammation and kidney remodeling.

Short-term MyD88 inhibition ameliorates cardiac graft rejection and promotes donor-specific hyporesponsiveness of skin grafts in mice

Recognition of evolutionarily conserved ligands by Toll-like receptors (TLRs) triggers signaling cascades in innate immune cells to amplify adaptive immune responses. Nearly all TLRs require MyD88 to transduce downstream signaling. MyD88 deficiency has been shown to promote the allograft acceptance in mice. However, direct evidence for therapeutic potential of MyD88 inhibitors remains lacking. Herein, we used a MyD88 inhibitor, namely ST2825, to explore its therapeutic potential and mechanisms in fully allogeneic skin and heart transplant models. Phenotypic maturation of dendritic cells stimulated by TLR ligands was alleviated by ST2825 in parallel with reduced T-cell proliferation in vitro. A short-course treatment with ST2825 significantly prolonged cardiac graft survival (mean survival time = 18.5 ± 0.92 days vs. 7.25 ± 0.46 days). ST2825-treated group had significantly reduced proinflammatory cytokines in allografts compared with control group. ST2825 combined with anti-CD154 induced long-term skin allograft acceptance in about one-third of recipients (>100 days). 'Skin-tolerant' recipients showed attenuated donor-specific IFN-γ responses, intact IL-4 responses, and compromised alloantibody responses. We conclude that MyD88 inhibitor ST2825 attenuates acute cardiac rejection and promotes donor-specific hyporesponsiveness in stringent skin transplant models. The direct evidence suggests that pharmacological inhibition of MyD88 hold promising potential for transplant rejection.

Toll-like receptors and chronic inflammation in rheumatic diseases: new developments

In the past few years, new developments have been reported on the role of Toll-like receptors (TLRs) in chronic inflammation in rheumatic diseases. The inhibitory function of TLR10 has been demonstrated. Receptors that enhance the function of TLRs, and several TLR inhibitors, have been identified. In addition, the role of the microbiome and TLRs in the onset of rheumatic diseases has been reported. We review novel insights on the role of TLRs in several inflammatory joint diseases, including rheumatoid arthritis, systemic lupus erythematosus, gout and Lyme arthritis, with a focus on the signalling mechanisms mediated by the Toll-IL-1 receptor (TIR) domain, the exogenous and endogenous ligands of TLRs, and the current and future therapeutic strategies to target TLR signalling in rheumatic diseases.

Targeted therapeutics in SLE: emerging strategies to modulate the interferon pathway

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by impaired immune tolerance, resulting in the generation of pathogenic autoantibodies and immune complexes. Although autoreactive B lymphocytes have been the first targets for biologic therapies in SLE, the importance of the innate immune system, and in particular, pathways involved in interferon (IFN) signaling, has emerged. There are now data supporting a central role for a plasmacytoid dendritic cell-derived type I IFN pathway in SLE, with a number of biologic therapeutics and small-molecule inhibitors undergoing clinical trials. Monoclonal antibodies targeting IFN-α have completed phase II clinical trials, and an antibody against the type I IFN receptor is entering a phase III trial. However, other IFNs, such as IFN gamma, and the more recently discovered type III IFNs, are also emerging as targets in SLE; and blockade of upstream components of the IFN signaling pathway may enable inhibition of more than one IFN subtype. In this review, we discuss the current understanding of IFNs in SLE, focusing on emerging therapies.

B-cell hyperfunction in children with immune thrombocytopenic purpura persists after splenectomy

BACKGROUND

Immune thrombocytopenic purpura (ITP) is characterized by reduced platelet count secondary to immune-mediated destruction, this results in an increased bleeding risk. Autoantibodies binding to platelets tag them for premature destruction in the spleen. For this reason, splenectomy is often performed as treatment of chronic forms of disease that are resistant to pharmacological therapy.

METHODS

We studied 30 patients with ITP and compared them with age-matched controls.

RESULTS

We show that B cells of patients with chronic ITP are intrinsically hyperreactive, producing more than normal IgG in vivo and plasma cells in vitro. In normal individuals after splenectomy, a significant depletion of memory B cells is observed, associated with loss of reactivity to CpG oligodeoxynucleotide and consequent inability to form antibody-producing cells. In Enzyme-Linked ImmunoSpot Methods, we compared three splenectomized ITP patients relapsing after surgery, 30 healthy controls, and 37 individuals splenectomized for trauma, spherocytosis, thalassemia, nonhematological tumor, and other diseases.

CONCLUSIONS

We confirmed that B cells of ITP patients remain hyperreactive in vitro and form high numbers of antibody-producing cells after splenectomy. Thus, chronic ITP may be associated with intrinsic B-cell hyperfunction, leading to the production of antibodies with multiple specificities including that against platelets.

Toll-like receptors: potential targets for lupus treatment

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE.

Interaction of Intestinal Microorganisms with the Human Host in the Framework of Autoimmune Diseases

Autoimmune diseases, such as systemic lupus erythematosus (SLE), are caused by a complex interaction of environmental-, genetic-, and sex-related factors. Although SLE has traditionally been considered independent from the microbiota, recent work published during the last 5 years suggests a strong connection between SLE and the composition of our gut commensals as one of the main environmental factors linked to this disease. Preliminary data have evidenced that (i) interaction of certain microbial-derived molecules with specific cell receptors and (ii) the influence of certain commensal microorganisms over specific immune cell subsets plays an important role in the pathogenesis of SLE and SLE-like diseases. In addition, epigenetic changes driven by certain microbial groups have been recently proposed as an additional link between gut microbiota and SLE. As immune responses elicited against commensal bacteria are deeply dependent on the composition of the latter, and as microbial populations can be modified by dietary interventions, identifying the precise gut microorganisms responsible for worsening the SLE symptoms is of crucial importance for this and other SLE-related diseases, including antiphospholipid syndrome or lupus nephritis. In this minireview, the current knowledge on the relationships between microbes and SLE and SLE-related diseases is compiled and discussed.

Dioscin attenuates renal ischemia/reperfusion injury by inhibiting the TLR4/MyD88 signaling pathway via up-regulation of HSP70

We previously reported the effect of dioscin against hepatic ischemia/reperfusion injury (IRI) in rats. However, little is known concerning the role of dioscin in renal IRI. In the present study, rats were subjected to IRI and dioscin was intragastrically administered for seven consecutive days before surgery. In vitro models of hypoxia/reoxygenation were developed in NRK-52E and HK-2 cells, which were prophylactically treated with or without dioscin. The results showed that dioscin significantly decreased serum BUN and Cr levels, and markedly attenuated cell injury. Mechanistic studies showed that dioscin significantly increased HSP70 levels, decreased the levels of TLR4, MyD88, TRAF6, COX-2, JNK, ERK and p38 MAPK phosphorylation, suppressed the nuclear translocation of NF-κB and HMGB1, and subsequently decreased the mRNA levels of IL-1β, IL-6, TNF-α, ICAM-1 and IFN-γ. Moreover, HSP70 siRNA or TLR4 DNA reversed the nephroprotective effects of dioscin, while dioscin still significantly down-regulated the TLR4 signaling pathway. Furthermore, by inhibiting MyD88 with ST2825 (a MyD88 inhibitor), renal IRI was significantly attenuated, suggesting that the effect of dioscin against renal IRI depended on MyD88. Our results suggested that dioscin had a potent effect against renal IRI through suppressing the TLR4/MyD88 signaling pathway by up-regulating HSP70. These data provide new insights for investigating the natural product with the nephroprotective effect against IRI, which should be developed as a new therapeutic agent for the treatment of acute kidney injury in the future.

Correlation between TLR9 Expression and Cytokine Secretion in the Clinical Diagnosis of Systemic Lupus Erythematosus

To investigate the correlation between TLR9 and cytokine secretion in SLE diagnosis and treatment. A total of 66 cases (39 SLE and 27 healthy donors) were enrolled in this study. The CD20+ labeled B cells were isolated from SLE patients. TLR9 mRNA expression from SLE tissues and B cells was detected using RT-PCR. The cytokine secretion in B cells were measured using ELISA. Correlation between TLR9 expression and cytokines secretion was analyzed using gene silencing method. Compared with the controls, TLR9 expression was significantly high in SLE patients tissues, as well as in B cells. Expressions of IL-6 and ds-DNA antibody were high in SLE patients serum and were positively correlated with TLR9 level in SLE patients (IL-6, R² = 0.768; ds-DNA antibody, R² = 0.730). The IL-6 and ds-DNA expression were significantly decreased by silencing TLR9 compared to the controls. Moreover, silencing TLR9 significantly decreased cytokines secretion including IL-6, IL-10, and IL-1rα, as well as the pathway-associated protein expression, including ICOS and Foxp3. The successful application of TLR9 silencing method in human SLE B cells may loan theatrical basis for the possibility of TLR9 genetic therapy in SLE diagnosis and treatment.

Inhibition of B-cell proliferation and antibody production by mesenchymal stromal cells is mediated by T cells

Bone marrow (BM)-derived mesenchymal stromal cells (MSCs), endowed with immunosuppressive and anti-inflammatory properties, represent a promising tool in immunoregulatory and regenerative cell therapy. Clarifying the interactions between MSCs and B-lymphocytes may be crucial for designing innovative MSC-based strategies in conditions in which B cells play a role, including systemic lupus erythematosus (SLE) and rejection of kidney transplantation. In this study, we show that, both in healthy subjects and in patients, in vitro B-cell proliferation, plasma-cell differentiation, and antibody production are inhibited by BM-derived MSCs when peripheral blood lymphocytes are stimulated with CpG, but not when sorted B cells are cultured with MSCs+CpG. Inhibition is restored in CpG+MSC cocultures when sorted T cells are added to sorted B cells, suggesting that this effect is mediated by T cells, with both CD4(+) and CD8(+) cells playing a role. Moreover, cell-cell contact between MSCs and T cells, but not between MSCs and B cells, is necessary to inhibit B-cell proliferation. Thus, the presence of functional T cells, as well as cell-cell contact between MSCs and T cells, are crucial for B-cell inhibition. This information can be relevant for implementing MSC-based therapeutic immune modulation in patients in whom T-cell function is impaired.

Impact analysis of autoantibody level and NR2 antibody level in neuropsychiatric SLE treated by methylprednisolone combined with MTX and DXM intrathecal injection

The objective is to explore the clinical curative effects of methylprednisolone combined with MTX and DXM intrathecal injection in treating neuropsychiatric systemic lupus erythematosus (NPSLE) and its effects on autoantibody level and anti-N-methyl-D-aspartate receptor subtype NR2a/2b antibody (anti-NR2 antibody) level. Thirty six admitted NPSLE patients were treated by methylprednisolone combined with MTX and DXM intrathecal injection. Thirty six SLE patients without neuropsychiatric symptoms were selected as non-NPSLE group. Clinical indexes including SLE activity index, erythrocyte sedimentation rate (ESR), cerebrospinal fluid pressure (CSFP), cerebrospinal fluid protein were observed before and after treatment. Autoantibodies including anti-nuclear antibody (ANA), anti-double stranded DNA antibody (anti-dsDNA antibody), anti-extractable nuclear antigen antibody (ENA-Ab) were detected before and after treatment. Enzyme linked immunosorbent assay was used to detect NR2 antibody level before and after treatment in two groups. Upon treatment of methylprednisolone combined with MTX and DXM intrathecal injection, SLE activity index, ESR, CSFP, cerebrospinal fluid protein of 36 NPSLE patients were significantly decreased. Before treatment, positive rates of ANA, anti-dsDNA antibody, and anti-ENA antibody in both NPSLE group and non-NPSLE group had no significant difference. However, positive rate of anti-NR2 antibody in NPSLE group was significantly higher than that of non-NPSLE group. After treatment, positive rates of autoantibodies and anti-NR2 antibody in both NPSLE and non-NPSLE group were significantly decreased. Anti-NR2 antibody can be a screening index of NPSLE, and methylprednisolone combined with MTX and DXM intrathecal injection has significant curative effects and can effectively decrease autoantibody level and anti-NR2 antibody level.

Drug-like analogues of the parasitic worm-derived immunomodulator ES-62 are therapeutic in the MRL/Lpr model of systemic lupus erythematosus

INTRODUCTION

ES-62, a phosphorylcholine (PC)-containing immunomodulator secreted by the parasitic worm Acanthocheilonema viteae, protects against nephritis in the MRL/Lpr mouse model of systemic lupus erythematosus (SLE). However, ES-62 is not suitable for development as a therapy and thus we have designed drug-like small molecule analogues (SMAs) based around its active PC-moiety. To provide proof of concept that ES-62-based SMAs exhibit therapeutic potential in SLE, we have investigated the capacity of two SMAs to protect against nephritis when administered to MRL/Lpr mice after onset of kidney damage.

METHODS

SMAs 11a and 12b were evaluated for their ability to suppress antinuclear antibody (ANA) generation and consequent kidney pathology in MRL/Lpr mice when administered after the onset of proteinuria.

RESULTS

SMAs 11a and 12b suppressed development of ANA and proteinuria. Protection reflected downregulation of MyD88 expression by kidney cells and this was associated with reduced production of IL-6, a cytokine that exhibits promise as a therapeutic target for this condition.

CONCLUSIONS

SMAs 11a and 12b provide proof of principle that synthetic compounds based on the safe immunomodulatory mechanisms of parasitic worms can exhibit therapeutic potential as a novel class of drugs for SLE, a disease for which current therapies remain inadequate.

Expression of Toll-like receptor -7 and -9 in B cell subsets from patients with primary Sjögren's syndrome

Introduction

Sjögren’s syndrome (SS) is a rheumatic autoimmune disease characterized by inflammation of exocrine glands. As autoantibodies are present in a majority of patients, B cells have been suggested to play an important role in onset and development of the disease. Toll-like receptors (TLRs) are pattern recognition receptors triggering innate immune responses. Since an increased expression of TLRs has been detected in other rheumatic diseases the purpose of this study was to explore TLRs in B cells of SS patients.

Methods

The expression of TLR-7 and -9 in B cell subsets of 25 patients with primary SS (pSS) and 25 healthy controls was analysed in peripheral blood using flow cytometry and real time quantitative PCR.

Results

We detected similar levels of CD19⁺ B cells in pSS patients and healthy controls. An increased number of naïve B cells, as well as fewer pre-switched memory B cells were found in pSS patients. No significant differences were observed in TLR-7 and -9 expression in B cells between pSS patients and healthy controls.

Conclusion

This study shows that pSS patients have an alteration in the B cell subpopulation composition compared to controls, with less pre-switched memory B cells and more naïve B cells. We did not detect any significant disparities in TLR-7 and -9 expression between the two groups.

Altered B cell homeostasis and toll-like receptor 9-driven response in type 1 diabetes carriers of the C1858T PTPN22 allelic variant: implications in the disease pathogenesis

Type 1 diabetes is an autoimmune disease caused by the destruction of pancreatic beta cells by autoreactive T cells. Among the genetic variants associated with type 1 diabetes, the C1858T (Lyp) polymorphism of the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene alters the function of T cells but also of B cells in innate and adaptive immunity. The Lyp variant was shown to diminish interferon production and responses upon Toll-like receptor stimulation in macrophages and dendritic cells, possibly leading to uncontrolled infections as triggers of the diabetogenic process. The aim of this study was to unravel the yet uncharacterized effects that the variant could exert on the immune and autoimmune responses, particularly regarding the B cell phenotype, in the peripheral blood lymphocytes of diabetic patients and healthy controls in basal conditions and after unmethylated bacterial DNA CpG stimulation. The presence of the Lyp variant resulted in a significant increase in the percentage of transitional B cells in C/T carriers patients and controls compared to C/C patients and controls, in C/T carrier patients compared to C/C controls and in C/T carrier patients compared to C/C patients. A significant reduction in the memory B cells was also observed in the presence of the risk variant. After four days of CpG stimulation, there was a significant increase in the abundance of IgM+ memory B cells in C/T carrier diabetics than in C/C subjects and in the groups of C/T carrier individuals than in C/C individuals. IgM- memory B cells tended to differentiate more precociously into plasma cells than IgM+ memory B cells in heterozygous C/T subjects compared to the C/C subjects. The increased Toll-like receptor response that led to expanded T cell-independent IgM+ memory B cells should be further investigated to determine the putative contribution of innate immune responses in the disease pathogenesis.