IL-17-producing T cells in lupus nephritis

Podocyte SIRPα reduction aggravates lupus nephritis via promoting T cell inflammatory responses

Signal-regulatory protein alpha (SIRPα) has recently been found to be highly expressed in podocytes and is essential for maintaining podocyte function. However, its immunoregulatory function in podocytes remains elusive. Here, we report that SIRPα controls podocyte antigen presentation in specific T cell activation via inhibiting spleen tyrosine kinase (Syk) phosphorylation. First, podocyte SIRPα under lupus nephritis (LN) conditions is strongly downregulated. Second, podocyte-specific deletion of SIRPα exacerbates renal disease progression in lupus-prone mice, as evidenced by an increase in T cell infiltration. Third, SIRPα deletion or knockdown enhances podocyte antigen presentation, which activates specific T cells, via enhancing Syk phosphorylation. Supporting this, Syk inhibitor GS-9973 prevents podocyte antigen presentation, resulting in a decrease of T cell activation and mitigation of renal disease caused by SIRPα knockdown or deletion. Our findings reveal an immunoregulatory role of SIRPα loss in promoting podocyte antigen presentation to activate specific T cell immune responses in LN.

Clinical research progress of novel biologics for the treatment of lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of immune tolerance. Lupus nephritis (LN) is one of the most common manifestations of severe organ damage in SLE, and also an important cause of disability and death. Its pathogenesis is associated with immune abnormalities such as immune cells, cytokines, and immune complex deposition. Traditional immunosuppressive therapy has been unable to meet the treatment needs of patients while bringing them toxic effects. In recent years, targeted therapies have emerged, and several novel biologics have gradually entered people's sight. This review will briefly introduce the pathogenesis of LN and the mechanism of biological targets, and summarize and analyze the clinical trials of new biologics for treating LN. Although not all biologics show positive results in clinical trials, the experience learned from these trials can help researchers adjust and plan future trial programs to seek better treatment methods.

Molecular consideration relevant to the mechanism of the comorbidity between psoriasis and systemic lupus erythematosus (Review)

Systemic lupus erythematosus (SLE), a common autoimmune disease with a global incidence and newly diagnosed population estimated at 5.14 (range, 1.4-15.13) per 100,000 person-years and 0.40 million people annually, respectively, affects multiple tissues and organs; for example, skin, blood system, heart and kidneys. Accumulating data has also demonstrated that psoriasis (PS) can be a systemic inflammatory disease, which can affect organs other than the skin and occur alongside other autoimmune diseases, such as inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis and SLE. The current explanations for the possible comorbidity of PS and SLE include: i) The two diseases share susceptible gene loci; ii) they share a common IL-23/T helper 17 (Th17) axis inflammatory pathway; and iii) the immunopathogenesis of the two conditions is a consequence of the interactions between IL-17 cytokines with effector Th17 cells, T regulatory cells, as well as B cells. In addition, the therapeutic efficacy of IL-17 or TNF-α inhibitors has been demonstrated in PS, and has also become evident in SLE. However, the mechanisms have not been investigated. To the best of our knowledge, there remains a lack of substantial studies on the correlation between PS and SLE. In the present review, the literature, with regards to the epidemiology, genetic predisposition, inflammatory mechanisms and treatment of the patients with both PS and SLE, has been reviewed. Further investigations into the molecular pathogenic mechanism may provide drug targets that could benefit the patients with concomitant PS and SLE.

Integrated multiple microarray studies by robust rank aggregation to identify immune-associated biomarkers in Crohn's disease based on three machine learning methods

Crohn's disease (CD) is a complex autoimmune disorder presumed to be driven by complex interactions of genetic, immune, microbial and even environmental factors. Intrinsic molecular mechanisms in CD, however, remain poorly understood. The identification of novel biomarkers in CD cases based on larger samples through machine learning approaches may inform the diagnosis and treatment of diseases. A comprehensive analysis was conducted on all CD datasets of Gene Expression Omnibus (GEO); our team then used the robust rank aggregation (RRA) method to identify differentially expressed genes (DEGs) between controls and CD patients. PPI (protein‒protein interaction) network and functional enrichment analyses were performed to investigate the potential functions of the DEGs, with molecular complex detection (MCODE) identifying some important functional modules from the PPI network. Three machine learning algorithms, support vector machine-recursive feature elimination (SVM-RFE), random forest (RF), and least absolute shrinkage and selection operator (LASSO), were applied to determine characteristic genes, which were verified by ROC curve analysis and immunohistochemistry (IHC) using clinical samples. Univariable and multivariable logistic regression were used to establish a machine learning score for diagnosis. Single-sample GSEA (ssGSEA) was performed to examine the correlation between immune infiltration and biomarkers. In total, 5 datasets met the inclusion criteria: GSE75214, GSE95095, GSE126124, GSE179285, and GSE186582. Based on RRA integrated analysis, 203 significant DEGs were identified (120 upregulated genes and 83 downregulated genes), and MCODE revealed some important functional modules in the PPI network. Machine learning identified LCN2, REG1A, AQP9, CCL2, GIP, PROK2, DEFA5, CXCL9, and NAMPT; AQP9, PROK2, LCN2, and NAMPT were further verified by ROC curves and IHC in the external cohort. The final machine learning score was defined as [Expression level of AQP9 × (2.644)] + [Expression level of LCN2 × (0.958)] + [Expression level of NAMPT × (1.115)]. ssGSEA showed markedly elevated levels of dendritic cells and innate immune cells, such as macrophages and NK cells, in CD, consistent with the gene enrichment results that the DEGs are mainly involved in the IL-17 signaling pathway and humoral immune response. The selected biomarkers analyzed by the RRA method and machine learning are highly reliable. These findings improve our understanding of the molecular mechanisms of CD pathogenesis.

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.

The role of IL-17 and anti-IL-17 agents in the immunopathogenesis and management of autoimmune and inflammatory diseases

Interleukin-17 (IL-17) is a proinflammatory cytokine involved in chronic inflammation occurring during the pathogenesis of allergy, malignancy, and autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and psoriasis. IL-17 is produced by multiple cell types of adaptive and innate immunity, including T helper 17 cells, CD8 + T cells, γδ T cells, natural killer T cells, and innate lymphoid cells. Monoclonal antibodies (mAbs) targeting IL-17 and/or IL-17R would be a potential approach to study this therapeutic tool for these diseases. In the current review, we aimed to highlight the characteristics of IL-17 and its important role in the pathogenesis of related diseases. Critical evaluation of the mAbs targeting IL-17A and IL-17 receptors (e.g., Ixekizumab, Secukinumab, and Brodalumab) in various immune-mediated diseases will be provided, and finally, their clinical efficacy and safety will be reported.

Secukinumab on Refractory Lupus Nephritis

Lupus nephritis (LN) is the most frequent severe organ manifestation of systemic lupus erythematosus (SLE). About 30% of patients are refractory to treatment. The authors report a case of treatment of LN with interleukin-17-targeted therapy, demonstrating its possible benefit, after reports of T helper 17 cell involvement in SLE pathogenesis.

We present the case of a childbearing age woman with SLE, who developed refractory LN despite all the indicated therapeutic options. During follow up, infection with human papillomavirus was detected, a possible trigger, and the following management was based on this discovery. We currently know that cytokines play a major role in tissue damage and interleukin-17 (IL-17) seems to be a fundamental key in SLE and LN, having shown its expression in renal glomeruli and urinary sediment. Thus, it was decided to start treatment with an anti-IL-17A antibody, secukinumab. After starting secukinumab, clinical and biological features improved and complete renal response was achieved.

5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative attenuates lupus nephritis with less effect to thymocyte development

Retinoic‑acid‑receptor‑related orphan nuclear hormone receptor gamma t (RORγt), a critical transcriptional factor of Th17 cells, is a potential therapeutic target for Th17-mediated autoimmune diseases. In addition, RORγt is essential for thymocyte survival and lymph node development, and RORγt inhibition or deficiency causes abnormal thymocyte development, thymus lymphoma, and lymph node defect. Recent study demonstrated that specific regulation of Th17 differentiation related to the hinge region of RORγt. In this research, we investigated the effect of RORγt inhibitor, 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative (TTP), in the therapy of lupus nephritis and its safety on thymocyte development. We demonstrated that TTP repressed the development of Th17 cells and ameliorated the autoimmune disease manifestation in the pristane-induced lupus nephritis mice model. The treatment of TTP in the mice did not interfere with thymocyte development, including total thymocyte number and proportion of CD4+CD8+ double-positive populations in the thymus, and had no substantial effects on the pathogenesis of thymoma. The TTP had a stronger affinity with full-length RORγt protein compared with the truncated RORγt LBD region via surface plasmon resonance, which indicated TTP binding to RORγt beyond LBD region. Molecular docking computation showed that the best binding pocket of TTP to RORγt is located in the hinge region of RORγt. In summary, as a RORγt inhibitor, TTP had a potential to develop the clinical medicine for treating Th17-mediated autoimmune diseases with low safety risk for thymocyte development.

Circulating IL-17 Level Is Positively Associated with Disease Activity in Patients with Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis

Previous studies on the relationship between the circulating level of interleukin-17 (IL-17) and disease activity in systemic lupus erythematosus (SLE) were contradictory. This study is aimed at quantitatively assessing the correlation between the circulating IL-17 level and disease activity in SLE patients. A systematic search for related literature was conducted via PubMed, Web of Science, EMBASE, and Cochrane Library (up to January 26, 2021). The relationship between circulating IL-17 levels and SLE activity was evaluated using Fisher's z value, which was then converted to r. The standardized mean difference (SMD) and its 95% confidence interval (CI) were used to describe the difference between the circulating IL-17 level in patients with active and inactive SLE. STATA 16.0 was used to perform statistical analysis. Random-effects model was performed to synthesize data. Twenty-six studies involving 1,560 SLE patients were included in this review. The pooled r value was 0.38 (95% CI: 0.25-0.50; I² = 83.8%, P < 0.001) between the SLE activity and circulating level of IL-17. Patients with active SLE had higher level of circulating IL-17 than that of inactive (pooled SMD = 0.95, 95% CI: 0.38-1.53; I² = 90.5%, P < 0.001). The subgroup analysis suggested that the region and detection method of circulating IL-17 might not be a source of heterogeneity. No significant publication bias was found. In summary, circulating IL-17 level has a low positive relationship with SLE activity. It is necessary to carefully consider the use of circulating IL-17 as a biomarker of the disease activity in SLE patients. The relationship between the circulating level of IL-17 and SLE activity should be further confirmed in randomized controlled studies.

NK1.1- natural killer T cells upregulate interleukin-17 expression in experimental lupus nephritis

Interleukin (IL)-17-secreting invariant natural killer T (NKT) cells are involved in several inflammatory diseases. However, their role in lupus nephritis (LN) has not been fully characterized. Samples from patients with LN or glomerulonephritis and healthy controls were obtained, and elevated IL-17+ NKT cell numbers and IL-17 expression were observed in blood cells and kidneys, respectively, in patients with LN. Comparison of a mouse model of experimental autoimmune LN with the parental strain (NKT-deficient B6.CD1d-/- mice) revealed improved proteinuria, disease severity, and histopathology and decreased levels of chemokine (C-X-C motif) ligand 16 and T cell receptor-α variable 14 expression. Spleens and kidneys of B6.CD1d-/- mice also showed downregulation of inflammatory markers and IL-17. In coculture with renal mesangial and NKT cells, inflammatory markers and IL-17 were upregulated following α-galactosylceramide treatment and downregulated after treatment with IL-17-blocking antibodies. This was most prominent with killer cell lectin-like receptor subfamily B member 1 C (NK1.1)- NKT cells. Thus, IL-17 is upregulated in LN. Activation of NKT cells regulates IL-17-related immune responses systemically and in the kidneys, primarily via NK1.1- NKT cells. IL-17-secreting NK1.1- NKT cells could serve as diagnostic and therapeutic targets for LN.NEW & NOTEWORTHY This study makes a significant contribution to the literature because our results indicate that IL-17 is upregulated in lupus nephritis and that natural killer T (NKT) cells are involved in its pathogenesis. Activation of NKT cells regulates IL-17-related immune responses, both systemically and in the kidney, and this mainly involves NK1.1- NKT cells. Furthermore, IL-17-secreting NK1.1- NKT cells could serve as a diagnostic and therapeutic target for lupus nephritis.

Current Insights and Future Prospects for Targeting IL-17 to Treat Patients With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune cell abnormalities which lead to the production of autoantibodies and the deposition of immune complexes. Interleukin (IL)-17-producing cells play an important role in the pathogenesis of the disease, making them an attractive therapeutic target. Studies in lupus-prone mice and of ex vivo cells from patients with SLE humans have shown that IL-17 represents a promising therapeutic target. Here we review molecular mechanisms involved in IL-17 production and Th17 cell differentiation and function and an update on the role of IL-17 in autoimmune diseases and the expected usefulness for targeting IL-17 therapeutically.

Lupus nephritis: clinical presentations and outcomes in the 21st century

Lupus nephritis (LN) is a frequent and severe manifestation of SLE. Along the decades, the epidemiology of LN and its clinical presentation have been changing. However, even though retrospective cohort studies report a decreased mortality rate and an improvement in the disease prognosis, the percentage of patients progressing into end stage renal disease (ESRD) keeps steady despite the improvements in therapeutic strategies. Current in-use medications have been available for decades now, yet over the years, regimens for optimizing their efficacy and minimizing toxicity have been developed. Therapeutic research is now moving towards the direction of precision medicine and several new drugs, targeting selectively different pathogenetic pathways, are currently under evaluation with promising results. In this review, we address the main changes and persistent unmet needs in LN management throughout the past decades, with a focus on prognosis and upcoming treatments.

Analysis of the Clinical Effects of the Combination of Mycophenolate Mofetil with Either Tacrolimus or Cyclophosphamide

OBJECTIVES

Here, we aimed to compare the clinical effects of mycophenolate mofetil combined with either tacrolimus or with cyclophosphamide on lupus nephritis (LN) and to analyze their influence on the expression of cystatin C and on transforming growth factor-1 (TGF-β1).

METHODS

A total of 234 patients were randomly divided into two groups: group A, for mycophenolate mofetil combined with tacrolimus (n=117) and group B, for mycophenolate mofetil combined with cyclophosphamide (n=117). The enzyme-linked immunosorbent assay was adopted to detect the expression levels of serum TGF-β1 and cystatin C before and after treatment.

RESULTS

The total effectiveness rate in group A was much higher than that in group B. The times of effectiveness and effect validity in group A were much lower than those in group B. The expression levels of serum TGF-β1 and cystatin C decreased slightly after treatment in the two groups, and those of group A were much lower than those of group B.

CONCLUSIONS

The combination of mycophenolate mofetil and tacrolimus showed better clinical efficacy on LN and was safer than that of mycophenolate mofetil and cyclophosphamide. Moreover, the drug combination of mycophenolate mofetil and tacrolimus greatly reduced the expression levels of serum TGF-β1 and cystatin C.

Association of interleukin-17A gene polymorphisms and susceptibility to systemic lupus erythematosus in Egyptian children and adolescents: a multi-centre study

BACKGROUND

Recently, the interleukin-17A (IL-17A) gene has emerged as a potential candidate gene for autoimmune disorders, including systemic lupus erythematosus (SLE).

OBJECTIVES

This study aimed to investigate whether IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T could be susceptibility markers for juvenile-onset SLE (JSLE) and lupus nephritis (LN) in Egyptian children and adolescents.

METHODS

In this multi-centre study, we genotyped 320 patients diagnosed with JSLE and 320 matched control children for three IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T using TaqMan probe-based real-time polymerase chain reaction. Meanwhile, IL-17A serum levels were assessed using ELISA.

RESULTS

The IL-17 rs2275913 A/A genotype and A allele were more represented in JSLE patients compared to the control group (21% vs. 7%, odds ratio (OR) = 3.8, 95% confidence interval (CI) 1.78-5.5, p = 0.001, pBonf = 0.003 for the A/A genotype; 37% vs. 29%, OR = 1.4, 95% CI 1.11-1.8, p = 0.003, pBonf = 0.009 for the A allele. No significant difference was found for IL-17 rs8193036 and rs3748067 single nucleotide polymorphisms (SNPs) in genotype distribution or allele frequencies (p>0.05). Patients carrying the IL-17 rs2275913 A/A genotype and A allele were more likely to develop LN (OR = 5.64, 95% CI 2.39-13.77, pBonf = 0.001 for the A/A genotype; OR = 2.73, 95% CI 1.84-4.07, pBonf = 0.02 for the A allele).

CONCLUSION

The IL-17 rs2275913 A allele and A/A genotype were associated with high IL-17 serum levels and may contribute to susceptibility to JSLE and the development of LN in Egyptian children and adolescents. However, no significant association was evident between the studied IL-17A SNPs and other clinical phenotypes, disease activity scores or laboratory profile of JSLE.

Interleukin-34 as a marker for subclinical proliferative lupus nephritis

Background

Lupus nephritis (LN) is an ominous manifestation of systemic lupus erythematosus (SLE). Clinical renal affection is present in about 70% of lupus patients, and more patients have histological evidence of renal involvement without clinical manifestations. This study aimed to investigate the potential role of serum interleukin-34 (IL-34) as an early marker for the detection of silent LN.

Methods

Thirty-three lupus patients with silent LN (group I), 37 patients with clinical LN (group II) and 20 controls were included. The SLE Disease Activity Index (SLEDAI), IL-34, anti-dsDNA antibodies and renal biopsy were assessed in all patients.

Results

Serum IL-34 levels were significantly higher in all lupus patients compared to healthy controls ( p < 0.001) and showed a significant positive correlation with SLEDAI score. SLE patients with positive anti-dsDNA antibodies had more active disease according to SLEDAI and higher levels of IL-34 than those with negative anti-dsDNA antibodies. In both studied groups, serum IL-34 levels were significantly higher in patients with proliferative LN (class III and class IV) than those with non-proliferative lupus (class II and class V) and controls. Yet, in both groups, IL-34 was not useful in differentiating active from chronic renal affection.

Conclusion

In lupus patients with insignificant proteinuria, serum levels of IL-34 distinguished the different histological classes of subclinical LN. Serum IL-34 may be used as a surrogate marker for early renal affection in silent LN, especially the proliferative type.

Deep Phenotyping of Urinary Leukocytes by Mass Cytometry Reveals a Leukocyte Signature for Early and Non-Invasive Prediction of Response to Treatment in Active Lupus Nephritis

Non-invasive biomarkers are necessary for diagnosis and monitoring disease activity in lupus nephritis (LN) to circumvent risks and limitations of renal biopsies. To identify new non-invasive cellular biomarkers in the urine sediment of LN patients, which may reflect kidney inflammation and can be used to predict treatment outcome, we performed in-depth urinary immune cell profiling by mass cytometry. We established a mass cytometric workflow to comparatively analyze the cellular composition of urine and peripheral blood (PB) in 13 patients with systemic lupus erythematosus (SLE) with active, biopsy-proven proliferative LN. Clinical and laboratory data were collected at the time of sampling and 6 months after induction of therapy in order to evaluate the clinical response of each patient. Six patients with different acute inflammatory renal diseases were included as comparison group. Leukocyte phenotypes and composition differed significantly between urine and paired PB samples. In urine, neutrophils and monocytes/macrophages were identified as the most prominent cell populations comprising together about 30%–83% of nucleated cells, while T and B lymphocytes, eosinophils, and natural killer (NK) cells were detectable at frequencies of <10% each. The majority of urinary T cells showed phenotypical characteristics of activated effector memory T cells (EM) as indicated by the co-expression of CD38 and CD69 – a phenotype that was not detectable in PB. Kidney inflammation was also reflected by tissue-imprinted macrophages, which phenotypically differed from PB monocytes by an increased expression of HLA-DR and CD11c. The presence of activated urinary T cells and macrophages could be used for differential diagnosis of proliferative LN forms and other renal pathologies. Most interestingly, the amount of EM in the urine sediment could be used as a biomarker to stratify LN patients in terms of response to induction therapy. Deep immunophenotypic profiling of urinary cells in LN allowed us to identify a signature of activated T cells and macrophages, which appear to reflect leukocytic infiltrates in the kidney. This explorative study has not only confirmed but also extended the knowledge about urinary cells as a future non-invasive biomarker platform for diagnosis and precision medicine in inflammatory renal diseases.

Double negative T cells, a potential biomarker for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that is a challenge to diagnose and treat. There is an urgent need for biomarkers to help define organ involvement, and more effective therapies. A unique population of T cells, the CD3⁺CD4⁻CD8⁻ (DNeg) cells, is significantly increased in lupus patients. Twenty-seven cases (53%) of pediatric SLE patients had elevated DNeg cells in their peripheral blood, which correlated with kidney function (R² = 0.54). Significant infiltration of DNeg cells was observed in both adult and pediatric lupus kidneys by immunofluorescence. For the first time, this study provides direct evidence that DNeg cells facilitate kidney injury in preclinical 8-week-old MRL/lpr lupus mice. In lupus mice, the increase in DNeg cells tracked with worsening disease and correlated with kidney function (R² = 0.85). Our results show that DNeg cells per se can cause kidney dysfunction, increase in number with increase in disease pathology, and could serve as a potential biomarker.

Juvenile-onset systemic lupus erythematosus: Update on clinical presentation, pathophysiology and treatment options

Juvenile-onset systemic lupus erythematosus (jSLE) accounts for up to 20% of all SLE patients. Key differences between juvenile- and adult-onset (aSLE) disease include higher disease activity, earlier development of damage, and increased use of immunosuppressive treatment in jSLE suggesting (at least partial) infectivity secondary to variable pathomechanisms. While the exact pathophysiology of jSLE remains unclear, genetic factors, immune complex deposition, complement activation, hormonal factors and immune cell dysregulation are involved to variable extents, promising future patient stratification based on immune phenotypes. Though less effective and potentially toxic, jSLE patients are treated based upon evidence from studies in aSLE cohorts. Here, age-specific clinical features of jSLE, underlying pathomechanisms, treatment options and disease outcomes will be addressed. Future directions to improve the care of jSLE patients, including implementation of the Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) recommendations, biomarkers, treat to target and personalized medicine approaches are discussed.

cAMP Response Element Modulator α Induces Dual Specificity Protein Phosphatase 4 to Promote Effector T Cells in Juvenile-Onset Lupus

Effector CD4⁺ T cells with increased IL-17A and reduced IL-2 production contribute to tissue inflammation and organ damage in systemic lupus erythematosus (SLE). Increased expression of the transcription factor cAMP response element modulator (CREM) α promotes altered cytokine expression in SLE. The aim of this study was to investigate CREMα-mediated events favoring effector CD4⁺ T cells in health and disease. Using CRISPR/Cas9 genome editing and lentiviral transduction, we generated CREMα-deficient and CREMα-overexpressing Jurkat T cells. Gene expression and regulatory events were assessed using luciferase reporter assays and chromatin immunoprecipitation. Interaction between CREMα and p300 was investigated using proximity ligation assays, coimmunoprecipitation, and knockdown of p300. Gene expression profiles of modified cells were compared with CD4⁺ T cells from patients with juvenile-onset SLE. We show that CREMα induces dual specificity protein phosphatase (DUSP) 4 in effector CD4⁺ T cells through corecruitment of p300. The transcriptional coactivator p300 mediates histone acetylation at DUSP4, prompting increased gene expression. Using DUSP4 transfection models and genetically modified CREM-deficient and CREMα-overexpressing T cells, we demonstrate the molecular underpinnings by which DUSP4 induces IL-17A while limiting IL-2 expression. We demonstrate that CD4⁺ T cells from patients with juvenile-onset SLE share phenotypical features with CREMα-overexpressing CD4⁺ T cells, including increased DUSP4 expression and imbalanced IL-17A and IL-2 production. Taken together, we describe CREMα-mediated mechanisms that involve the transcriptional upregulation of DUSP4, leading to imbalanced cytokine production by effector T cells. Our findings identify the CREMα/DUSP4 axis as a promising candidate in the search for biomarkers and therapeutic targets in SLE.

[Lupus nephritis]

Systemic lupus erythematosus is the most characteristic of auto-immune disorders that can lead to tissue damage in many organs, including kidney. Lupus nephritis occurs in 10 to 40% of lupus patients. Its clinical hallmark is the appearance of a proteinuria as soon as a 0.5 g/g or 0.5 g/d threshold, which calls for a renal histological evaluation in order to determine the lupus nephritis severity and the need for specific therapy. More than half of renal biopsies lead to the diagnosis of active lupus nephritis-class III or class IV A according to the ISN/RPS classification-that are the most severe in regards to renal prognosis and mortality. Their treatment aims to their clinical remission and to the prevention of relapse with minimal adverse effects for eventually the preservation of renal function, the prevention of other irreversible damage, and the reduction of risk of death. The remission is obtained through induction therapies of which the association of high dose steroids and cyclophosphamide is the most experienced. When this association must be challenged by the prevention of side-effect, in particular infertility, mycophenolate can be given instead of cyclophosphamide. Maintenance therapy, for the prevention of relapse, consists in mycophenolate or in azathioprine, mycophenolate being the most efficient however associated with a high risk of teratogenicity. Withdrawal of maintenance therapy is possible after two to three years in absence of high risk factors of relapse of lupus nephritis, however a reliable assessment of the risk of relapse is still lacking. Only pure membranous lupus nephritis (pure class V) associated with high level proteinuria requires specific therapies that usually associates steroids and an immunosuppressive drug. However, their choice hierarchy and even the use of less immunosuppressive strategies remain to be determined in terms of benefice over risk ratios. In spite of its trigger effect on lupus activity, pregnancy can be safe and successful if scheduled in the lowest risk periods with close multidisciplinary monitoring before, during and after. When necessary, renal replacement therapy does not require specific adaptation, renal transplantation is the best option when possible, as early as possible.

Epoxyeicosatrienoic Acid Analog EET-A Blunts Development of Lupus Nephritis in Mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that causes life threatening renal disease and current therapies are limited with serious side-effects. CYP epoxygenase metabolites of arachidonic acid epoxyeicosatrienoic acids (EETs) demonstrate strong anti-inflammatory and kidney protective actions. We investigated the ability of an orally active EET analog, EET-A to prevent kidney injury in a mouse SLE model. Twenty-weeks old female NZBWF1 (SLE) and age-matched NZW/LacJ (Non SLE) were treated with vehicle or EET-A (10 mg/kg/d, p.o.) for 14 weeks and urine and kidney tissues were collected at the end of the protocol. SLE mice demonstrated marked renal chemotaxis with 30-60% higher renal mRNA expression of CXC chemokine receptors (CXCR) and CXC chemokines (CXCL) compared to Non SLE mice. In SLE mice, the elevated chemotaxis is associated with 5-15-fold increase in cytokine mRNA expression and elevated inflammatory cell infiltration in the kidney. SLE mice also had elevated BUN, serum creatinine, proteinuria, and renal fibrosis. Interestingly, EET-A treatment markedly diminished renal CXCR and CXCL renal mRNA expression in SLE mice. EET-A treatment also reduced renal TNF-α, IL-6, IL-1β, and IFN-γ mRNA expression by 70-80% in SLE mice. Along with reductions in renal chemokine and cytokine mRNA expression, EET-A reduced renal immune cell infiltration, BUN, serum creatinine, proteinuria and renal fibrosis in SLE mice. Overall, we demonstrate that an orally active EET analog, EET-A prevents renal injury in a mouse model of SLE by reducing inflammation.

Analysis of interleukin-17 and interleukin-23 for estimating disease activity and predicting the response to treatment in active lupus nephritis patients

Renal biopsy is a "gold standard" for establishing the diagnosis and assessing prognosis and monitoring therapy in lupus nephritis (LN) patients, but it is an invasive and inconvenient procedure. Evidences showed that interleukin-17(IL-17) and interleukin-23(IL-23) may be as alternative biomarkers for diagnosing LN, monitoring LN activity and predicting the response to treatment of LN. To analyze the roles of IL-17 and IL-23 in evaluation activity of LN and predicting active LN response to immunosuppressive treatment, by comparison between IL-17, IL-23 and clinical data of LN. Eighty patients with LN and 20 healthy volunteers were enrolled in this study. Plasma levels of IL-17 and IL-23 were detected by ELISA and clinical data were collected in patients with LN. Thirty-seven patients with active LN accepted immunosuppressive therapy and followed up to 6 months. The roles of IL-17 and IL-23 in evaluation the activity of LN and the predictability for active LN response to immunosuppressive treatment were analyzed. The ages or gender rations between LN patients and healthy controls were not significant difference at baseline. Baseline levels of IL-17 and IL-23 were higher in patients with active LN compare to them in patients with inactive LN or controls (P<0.001) and IL-23 in patients with inactive LN was higher than its in controls (P=0.004). IL-17 and IL-23 decreased significantly in active LN patients after 6 months therapy (P<0.001). The baseline level of IL-23 was significantly different in subgroups response to the immunosuppressive treatment in patients with active LN (P=0.0014). Baseline level of IL-23 in complete response group was lower than its in partial response group (P=0.0015) or nonresponse group (P=0.013). IL-17 was negative correlation with C3 (r=-0.44, P<0.001). IL-17 and IL-23 correlated with systemic lupus erythematosus (SLE) disease activity index (P<0.001). The correlation between IL-17 and LN pathological acute index (AI) was higher than the correlation between IL-23 and AI. (r=0.52, P<0.001 vs. r=0.41, P<0.001). Receiver Operation Characteristics (ROC) showed that IL-17 and IL-23 could be used to evaluate SLE disease activity index. IL-17 could be used as biomarker to evaluate pathological AI. IL-23 could be used as a predictor for predicting response to immunosuppressive treatment in patients with active LN. IL-17 and IL-23 may involve and contribute to LN. IL-17 could be used as a biomarker for LN clinical and pathological AI. IL-23 could be used as a predictor for predicting response to immunosuppressive treatment in patients with active LN.

The role of IL-17 in systemic lupus erythematosus and its potential as a therapeutic target

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibodies production and immune complex deposition with systemic clinical manifestations. Interleukin (IL)-17-producing cells play a crucial role in disease pathogenesis and represent an attractive therapeutic target. Areas covered: This review provides an update on the possibility of targeting IL-17 in SLE. The rational for this approach as well as currently available and future targets are discussed. Expert opinion: Although human expression studies and animal models indicate that IL-17 blocking may be a promising therapeutic strategy for SLE, direct evidence for IL-17 inhibition in SLE patients is unavailable. Biologic therapies and small-molecule drugs that target IL-17 production are required for the achievement of a favorable clinical effect in SLE patients.

Mechanisms of hypertension in autoimmune rheumatic diseases

Patients with autoimmune rheumatic diseases including rheumatoid arthritis and systemic lupus erythematosus have an increased prevalence of hypertension. There is now a large body of evidence showing that the immune system is a key mediator in both human primary hypertension and experimental models. Many of the proposed immunological mechanisms leading to primary hypertension are paralleled in autoimmune rheumatic disorders. Therefore, examining the link between autoimmunity and hypertension can be informative for understanding primary hypertension. This review examines the prevalent hypertension, the immune mediators that contribute to the prevalent hypertension and their impact on renal function and how the risk of hypertension is potentially influenced by common hormonal changes that are associated with autoimmune rheumatic diseases.

Linked Articles

This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc

Decreased α7nAChR mRNA levels in peripheral blood monocytes are associated with enhanced inflammatory cytokine production in patients with lupus nephritis

The cholinergic anti-inflammatory pathway modulates cytokine release by activating alpha-7 nicotinic acetylcholine receptors (α7nAChR) in monocytes/macrophages. We aimed to determine the role of α7nAChR in lupus nephritis (LN). We enrolled 36 inactive and 35 active LN patients, 34 primary glomerulonephritis patients, and 35 healthy controls. Peripheral blood monocytes were isolated, and mRNA expression of α7nAChR, interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α) in monocytes was measured. α7nAChR and IL-10 mRNA levels were significantly decreased, but IL-6 was increased, in LN patients compared with healthy controls or glomerulonephritis patients (all P < 0.01). Interestingly, α7nAChR mRNA levels were negatively correlated to SLEDAI (r = -0.68, P < 0.01), anti-dsDNA (r = -0.38, P < 0.05), and proteinuria (r = -0.49, P < 0.01) levels, and positively correlated to serum complement C3 levels (r = 0.38, P < 0.05) in patients with active LN. Furthermore, α7nAChR mRNA levels were negatively correlated to TNF-α (r = -0.50, P < 0.01), IL-1β (r = -0.42, P < 0.05), IL-6 (r = -0.69, P < 0.01) mRNA levels, and positively correlated to IL-10 (r = 0.45, P < 0.01). TNF-α, IL-1β, and IL-6 protein levels in the supernatant of cultured monocytes from active LN patients were significantly higher, while IL-10 was lower, than that of healthy controls. PNU-282987, an α7nAChR agonist, significantly decreased TNF-α, IL-1β, and IL-6 but increased IL-10 in the monocyte culture supernatant of active LN patients, which were abolished by an α7nAChR antagonist methyllycaconitine. The effects of PNU-282987 were confirmed in lipopolysaccharides-stimulated monocytes. Taken together, these findings suggest that decrease in α7nAChR mRNA levels may play a role in LN and that activation of α7nAChR may inhibit inflammation in LN.

Epigenetics in SLE

Purpose of Review

Systemic lupus erythematosus is a severe autoimmune/inflammatory condition of unknown pathophysiology. Though genetic predisposition is essential for disease expression, risk alleles in single genes are usually insufficient to confer disease. Epigenetic dysregulation has been suggested as the missing link between genetic risk and the development of clinically evident disease.

Recent Findings

Over the past decade, epigenetic events moved into the focus of research targeting the molecular pathophysiology of SLE. Epigenetic alteration can be the net result of preceding infections, medication, diet, and/or other environmental influences. While altered DNA methylation and histone modifications had already been established as pathomechanisms, DNA hydroxymethylation was more recently identified as an activating epigenetic mark.

Summary

Defective epigenetic control contributes to uncontrolled cytokine and co-receptor expression, resulting in immune activation and tissue damage in SLE. Epigenetic alterations promise potential as disease biomarkers and/or future therapeutic targets in SLE and other autoimmune/inflammatory conditions.

Inhibition of HDAC6 activity in kidney diseases: a new perspective

Histone deacetylase 6 (HDAC6), a cytoplasmic enzyme that plays important roles in many biological processes, is one isoform of a family of HDAC enzymes that catalyse the removal of functional acetyl groups from proteins. HDAC6 stands out from the other members of this family because it almost exclusively deacetylates cytoplasmic proteins and exerts deacetylation-independent effects, which has led to the successful development of relatively isoform-specific inhibitors of its enzymatic action. Numerous studies have recently demonstrated that HDAC6 expression and activity are increased in kidney disease, such as autosomal dominant polycystic kidney disease (ADPKD), renal fibrosis, and acute kidney injury (AKI), among others. Moreover, HDAC6 inhibitors have been investigated for use in treating these diseases. In fact, HDAC6 inhibitors effectively limit the progression of kidney diseases, suggesting that targeting HDAC6 may provide a novel treatment approach. However, the primary challenge in developing HDAC6-targeted therapies is understanding how the renoprotective effect of NDAC6 inhibitors can be selectively harnessed. Here, we discuss the unique function of HDAC6 and recapitulate the alluring potential of its inhibitors in kidney diseases.

Administration of activated lymphocyte-derived DNA accelerates and aggravates lupus nephritis in B6/lpr mice: a new approach to modify a lupus murine model

B6/lpr mouse strain is a well-known systemic lupus erythematosus murine model characterized by uncontrolled lymphoproliferation and autoantibody production. However, it displays a delayed and mild development of lupus nephritis (LN), which is not conducive to the research of the pathogenesis and therapeutic strategies of this condition. Our previous study demonstrated that activated lymphocyte-derived DNA (ALD-DNA) could induce high urine protein levels and severe glomerulonephritis (GN) in BALB/c mice. In the present study, we tried to remedy delayed urine protein production and mild GN in B6/lpr mice via ALD-DNA immunization. We found that urine protein levels were enhanced significantly in B6/lpr mice 4 weeks after ALD-DNA immunization compared with those in unactivated lymphocyte-derived (UnALD)-DNA- and phosphate-buffered saline (PBS)-treated controls. Moreover, more serious GN and glomerular immune complex were observed in ALD-DNA-immunized B6/lpr mice. We further explored the mechanism, and found that ALD-DNA immunization promoted T helper type 17 (Th17) cell enrichment remarkably, which enhanced the proportion of autoantibody-secreting plasma cells and promoted the production of anti-dsDNA autoantibodies, leading to accelerated and aggravated LN. Our data demonstrated that ALD-DNA immunization could remedy delayed urine protein production and mild GN in B6/lpr mouse, which makes it more suitable for studies on the pathogenesis of and therapeutic strategies against LN.

La/SSB chimeric autoantibody receptor modified NK92MI cells for targeted therapy of autoimmune disease

It has been long sought to specifically eliminate B-cell clones that generate autoreactive antibodies, while sparing the immune system when combating autoimmune disease. Although it was impossible to achieve this goal before, newly developed techniques have made it feasible today. Autoantibodies against La/SSB were involved in several autoimmune diseases. Here, we aimed to introduce La/SSB epitope-based chimeric autoantibody receptors (CAAR) into NK92MI cells enabled it to destroy the corresponding La/SSB-specific B cell receptor (BCR) -bearing lymphoma cells (LaA-BCR-Romas, LaA-BCR-Maver-1, and LaA-BCR-Jurkat cells). Such cell lines could eliminate a part of the B-cells in the blood of patients positive for anti-La/SSB antibodies. The CAAR we used in this study was constructed by fusing fragments from the nucleus protein, La/SSB, with the TCR signaling molecules, CD28, CD137, and CD3ζ. Thus, this method could specifically destroy the La/SSB autoreactive B-cell clones. Our results might provide a new strategy to combat antibody-mediated autoimmune diseases.

A case of refractory lupus nephritis complicated by psoriasis vulgaris that was controlled with secukinumab

It has been reported that T helper 17 cells are involved in the pathogenesis of systemic lupus erythematosus, but there is no report on interleukin-17-targeted therapy. We report a case of a 62-year-old female who presented with psoriasis vulgaris and refractory lupus nephritis. Because her conditions were resistant to conventional treatment, and flow cytometry confirmed the proliferation of activated T helper 17 cells in peripheral blood, and examination of a renal biopsy tissue sample confirmed infiltration of numerous interleukin-17-positive lymphocytes to the renal interstitium, administration of the anti-interleukin-17A antibody secukinumab was initiated. After starting secukinumab the clinical and biological features were improved.

IL10 promoter haplotypes may contribute to altered cytokine expression and systemic inflammation in celiac disease

Celiac disease (CD) is an autoimmune/inflammatory condition triggered by dietary gluten intake in genetically predisposed individuals. Though associations with MHC class II HLA-DQ2 or -DQ8 are the primary and necessary genetic predisposition for CD, >97% of genetically predisposed individuals never develop CD. Cytokines were measured in the serum of CD patients and controls. Possible associations with IL10 promoter variants were investigated. Cytokine expression from PBMCs was monitored in response to gluten exposure, or CD3/TCR complex stimulation in the absence or presence of recombinant IL-10. Serum cytokines varied between patients with CD at the time of diagnosis, after dietary elimination of gluten, and healthy controls. Serum IL-17A reflected disease activity. Reduced IL-10 serum levels and altered IL-10 expression by PBMCs coincided with IL10 promoter haplotypes that encode for "low" IL-10 expression (ATA). Increased prevalence of ATA IL10 promoter haplotypes and subsequently reduced IL-10 expression may be an immunological cofactor in individuals genetically predisposed for the development of CD. Resulting cytokine imbalances may be utilized as disease biomarkers in CD.

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.

New insights into the immunopathogenesis of systemic lupus erythematosus

The aetiology of systemic lupus erythematosus (SLE) is multifactorial, and includes contributions from the environment, stochastic factors, and genetic susceptibility. Great gains have been made in understanding SLE through the use of genetic variant identification, mouse models, gene expression studies, and epigenetic analyses. Collectively, these studies support the concept that defective clearance of immune complexes and biological waste (such as apoptotic cells), neutrophil extracellular traps, nucleic acid sensing, lymphocyte signalling, and interferon production pathways are all central to loss of tolerance and tissue damage. Increased understanding of the pathogenesis of SLE is driving a renewed interest in targeted therapy, and researchers are now on the verge of developing targeted immunotherapy directed at treating either specific organ system involvement or specific subsets of patients with SLE. Accordingly, this Review places these insights within the context of our current understanding of the pathogenesis of SLE and highlights pathways that are ripe for therapeutic targeting.

DNA methylation in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease facilitated by aberrant immune responses directed against cells and tissues, resulting in inflammation and organ damage. In the majority of patients, genetic predisposition is accompanied by additional factors conferring disease expression. While the exact molecular mechanisms remain elusive, epigenetic alterations in immune cells have been demonstrated to play a key role in disease pathogenesis through the dysregulation of gene expression. Since epigenetic marks are dynamic, allowing cells and tissues to differentiate and adjust, they can be influenced by environmental factors and also be targeted in therapeutic interventions. Here, we summarize reports on DNA methylation patterns in SLE, underlying molecular defects and their effect on immune cell function. We discuss the potential of DNA methylation as biomarker or therapeutic target in SLE.

Serum 25-OH vitamin D level in treatment-naïve systemic lupus erythematosus patients: Relation to disease activity, IL-23 and IL-17

Objectives The aim of this study was to assess the vitamin D status in treatment-naïve SLE patients and its association with clinical and laboratory markers of disease activity, including serum levels of IL-17 and IL-23. Methods Fifty-seven treatment-naïve SLE patients along with 42 matched controls were included. SLEDAI score was used to estimate disease activity. Serum levels of 25(OH) D, IL-17 and IL-23 were measured. Results The median level of 25(OH) D in SLE patients (40.8; 4-70 ng/ml) was significantly lower than in the controls (47; 25-93 ng/ml) ( P = 0.001). A total of 38.6% of SLE cases had 25 (OH) D levels < 30 ng/ml (hypovitaminosis D) vs. 4.8% of the controls ( P < 0.0001). Apart from thrombocytopenia, vitamin D was not associated with clinical signs of SLE. There were negative correlations between serum 25(OH) D and serum levels of IL-17, IL-23 and ANA (rho = -0.5, -0.8, -0.5, P ≤ 0.05) in SLE patients. Conclusion Hypovitaminosis D is prevalent in treatment naïve SLE patients. It contributes to ANA antibody production and is associated with high serum levels of IL-23 and IL-17; thus they may trigger the inflammatory process in SLE.

Aberrant Epigenetic Regulation in the Pathogenesis of Systemic Lupus Erythematosus and Its Implication in Precision Medicine

Great progress has been made in the last decades in understanding the complex immune dysregulation in systemic lupus erythematosus (SLE), yet the efforts to pursue an effective treatment of SLE proved to be futile. The pathoetiology of SLE involves extremely complicated and multifactorial interaction among various genetic and epigenetic factors. Multiple gene loci predispose to disease susceptibility, and the interaction with epigenetic modifications mediated through sex, hormones, and the hypothalamo-pituitary-adrenal axis complicates susceptibility and manifestations of this disease. Finally, certain environmental and psychological factors probably trigger the disease via epigenetic mechanisms. In this review, we summarize and discuss recent epigenetic studies of SLE and suggest a personalized approach to the dissection of disease onset and therapy or precision medicine. We speculate that in the future, precision medicine based on epigenetic and genetic information could help guide more effective targeted therapeutic intervention.

Blockade of Interleukin-17 Restrains the Development of Acute Lung Injury

The acute respiratory distress syndrome (ARDS), a clinical complication of severe acute lung injury (ALI) in humans, is a leading cause of morbidity and mortality in critically ill patients. Here, we explored the association between IL-17 and development of ALI using LPS-induced murine model. We found that IL-17 level was elevated in bronchoalveolar lavage (BAL) fluid of ALI mice. Upregulation of IL-17 resulted in increased severity of ALI as evidenced by decreased body weight and survival rate, elevated level of total protein and albumin in BAL fluid, as well as more apparent histopathology changes of lung. Induction of ALI was impaired in IL-17-deficient mice. Management of IL-17 could modulate LPS-induced pulmonary inflammation, as reflected by the total cell and neutrophil counts, proinflammatory cytokines, as well as chemokines in BAL fluid. Of note, blockade of IL-17 effectively inhibited the lung inflammation and alleviated ALI severity. Finally, we confirmed the clinical relevance and found that IL-17 expression was elevated and associated with the disease severity in patients with ARDS. In essence, IL-17 was crucial for development of ALI, suggesting a potential application for IL-17-based therapy in clinical practice.

Lupus nephritis biomarkers

Lupus nephritis (LN), a potentially destructive outcome of SLE, is a real challenge in the management of SLE because of the difficulty in diagnosing its subclinical onset and identifying relapses before serious complications set in. Conventional clinical parameters such as proteinuria, GFR, urine sediments, anti-dsDNA and complement levels are not sensitive or specific enough for detecting ongoing disease activity in lupus kidneys and early relapse of nephritis. There has long been a need for biomarkers of disease activity in LN. Such markers ideally should be capable of predicting early sub-clinical flares and could be used to gauge response to therapy, thus obviating the need for serial renal biopsies with their possible hazardous complications. Since urine can be readily obtained, it lends itself as an obvious biological substrate. In this review, the use of urine and serum as sources of lupus nephritis biomarkers is described, and the results of biomarker discovery studies using candidate and proteomic approaches are summarized.

Human embryonic mesenchymal stem cells alleviate pathologic changes of MRL/Lpr mice by regulating Th7 cell differentiation

Recent evidence indicates that mesenchymal stem cells (MSC) derived from early embryonic tissues have better therapeutic ability as compared with adult tissue-derived stem cells. In the present study, we transplanted human early embryonic MSC (hMSC) into MRL/Lpr mice via tail vein injection to observe the therapeutic efficacy of hMSC and their impact on T helper 17 (Th17) cell differentiation in MRL/Lpr mice. Animals in hMSC treatment group received hMSC (1 × 10⁶/200 μL) via the tail vein at the age of 16 and 19 weeks. We found that hMSC treatment prolonged the survival of MRL/Lpr mice without inducing tumorigenesis, reduced urine protein, and alleviated the renal pathologic changes. In addition, it reduced the proportion of Th17 cells in the spleen of MRL/Lpr mice and the serum interleukin 17 (IL-17) concentration. Our in vitro experiment also demonstrated that hMSC could secrete Th17 differentiation-related cytokines of PGE2, IL-10 and TGF-β, and IFN-γ stimulation up-regulated the secretion of these immune regulating factors. The results of the present study suggest that hMSC therapy could alleviate systemic and local renal lesions in MRL/Lpr mice, probably by secreting immune regulating factors and regulating Th17 cell differentiation in MRL/Lpr mice.

Effect of Adoptive Transfer or Depletion of Regulatory T Cells on Triptolide-induced Liver Injury

Objective: The aim of this study is to clarify the role of regulatory T cell (Treg) in triptolide (TP)-induced hepatotoxicity.

Methods: Female C57BL/6 mice received either adoptive transfer of Tregs or depletion of Tregs, then underwent TP administration and were sacrificed 24 h after TP administration. Liver injury was determined according to alanine transaminase (ALT) and aspartate transaminase (AST) levels in serum and histopathological change in liver tissue. Hepatic frequencies of Treg cells and the mRNA expression levels of transcription factor Forkhead box P3 and retinoid orphan nuclear receptor γt (RORγt), interleukin-10 (IL-10), suppressor of cytokine signaling (SOCS), and Notch/Notch ligand were investigated.

Results: During TP-induced liver injury, hepatic Treg and IL-10 decreased, while T helper 17 cells cell-transcription factor RORγt, SOCS and Notch signaling increased, accompanied with liver inflammation. Adoptive transfer of Tregs ameliorated the severity of TP-induced liver injury, accompanied with increased levels of hepatic Treg and IL-10. Adoptive transfer of Tregs remarkably inhibited the expression of RORγt, SOCS3, Notch1, and Notch3. On the contrary, depletion of Treg cells in TP-administered mice resulted in a notable increase of RORγt, SOCS1, SOCS3, and Notch3, while the Treg and IL-10 of liver decreased. Consistent with the exacerbation of liver injury, higher serum levels of ALT and AST were detected in Treg-depleted mice.

Conclusion: These results showed that adoptive transfer or depletion of Tregs attenuated or aggravated TP-induced liver injury, suggesting that Tregs could play important roles in the progression of liver injury. SOCS proteins and Notch signaling affected Tregs, which may contribute to the pathogenesis of TP-induced hepatotoxicity.

T cells and IL-17 in lupus nephritis

Systemic lupus erythematosus (SLE) is a complicated autoimmune disorder characterized by autoantibodies production, immune complex formation, and immune dysregulation, resulting in damage of multiple organs including the kidney. Lupus nephritis (LN) is the most common severe manifestation of SLE involving the majority of patients. Even though there are a number of reports indicating that interleukin-17 (IL-17) and Th17 cells play important roles in the pathogenesis of LN, the precise molecular mechanisms underline the development of LN have not been totally elucidated. In this review, we briefly summarize general characteristics of T and IL-17 cells in SLE. In addition, we discuss in detail T cell signaling pathways which control IL-17 production in patients with LN and in glomerulonephritis in lupus-prone mice. A better understanding of signaling and gene regulation defects in LN will lead to the identification of novel therapeutic targets and predictive biomarkers for diagnosis and prognosis of this disease.

Immune cells and type 1 IFN in urine of SLE patients correlate with immunopathology in the kidney

The immunopathological events in the kidneys of lupus nephritis (LN) patients are poorly understood due in part to the difficulty in acquiring serial biopsies and the inherent limitations in their analysis. To identify a means to circumvent these limitations, we investigated whether immune cells of kidney origin are present in patient urine and whether they correlate with kidney pathology. Flow cytometry analysis was performed on peripheral blood and urine cells of 69 SLE patients, of whom 41 were LN patients. In addition, type I IFN (IFNα/β) levels were determined in plasma and urine by bioassay. Approximately 60% of non-LN patients had urine lymphocytes. In these patients, T cells were always present and predominantly CD8(+), while B cells were either absent or a mixture of naïve and memory B cells. In contrast, >90% of LN patients had urine lymphocytes. In half, the B and T cells resembled those in non-LN patient urine; however, in the remaining patients, the B cells were exclusively Ig-secreting plasmablasts or plasma cells (PB/PCs) and the T cells were predominantly CD4(+). In addition, pDCs and IFNα/β frequently accompanied PB/PCs. The majority of patients with urine PB/PCs presented with proliferative nephritis and a significant loss of kidney function, which in some cases had progressed to end stage renal disease (ESRD). In conclusion, urine can provide access to cells of kidney resident populations for phenotypic and functional characterization. Analysis of these cells provides insight into the kidney immunopathology and may serve as biomarkers to identify patients at risk for developing LN and progressing to ESRD.

Analysis of CD95 and CCR7 expression on circulating CD4(+) lymphocytes revealed disparate immunoregulatory potentials in systemic lupus erythematosus

Emerging data have implicated a critical role for CD4 in the pathogenesis of systemic lupus erythematosus (SLE). This study was designed to delineate the contribution of CD4(+) T cells in the pathogenesis of SLE disease. Forty-four patients (3 male: 41 female) and 20 healthy volunteers (4 male: 16 female) were included in the study. CD4(+) lymphocytes analysis was done using three-color flow cytometry with antibodies against human-CD95, a prototype cell death receptor, and the chemokine receptor-7 (CCR7) after gating for lymphocytes based on the forward and side scatter. Serum levels of IL-6, IL-12, IL-17, TNF-α and IL-10 cytokines were assayed using ELISA. Disease activity was assessed using the SLE disease activity index (SLEDAI). Based on the expression of CCR7 and CD95, CD4(+) lymphocytes were subdivided into three particular subsets; CD4(+)CD95(+)CCR7(+) cells, CD4(+)CD95(-)CCR7(+) cells and CD4(+)CD95(+)CCR7(-) cells. Percentage of CD4(+)CD95(+)CCR7(+) cell subset was significantly higher in patients with SLE with active disease (SLEDAI > 6) and inactive (SLEDAI < 6) as compared with controls (P = 0.005), and it showed a significant positive correlation with ANA titer (P = 0.01), and a negative correlation with WBCs count (P = 0.001). CD4(+)CD95(+)CCR7(-) cell subset was significantly higher in active SLE patients in comparison to patients with inactive disease and controls (P = 0.05, P = 0.005 respectively), and it correlates positively with SLEDAI, IL-6 and IL-17 levels (P = 0.001, 0.05, 0.01 respectively), and negatively with blood WBCs counts (P = 0.001). The third CD4(+)CD95(-)CCR7(+)cell subset was found significantly lower in SLE patients compared with controls, and it was found negatively correlated with IL-10, IL-6, and IL-17. The results show that CD4(+)CD95(+)subset lacking expression of CCR7 is associated with cell mediated inflammatory response as manifested by its correlation with signs of inflammation, inflammatory cytokines and disease activity index. Whereas, CD4(+)CD95(+)CCR7(+) correlate more with antibody immune responses as manifested by association with serum ANA. These data suggest disparate roles of these cell subsets in the pathophysiology of SLE. A better understanding of the characteristics of CD4 cell subsets may shed light on the pathogenesis of autoimmune diseases, particularly SLE.

T cells as a therapeutic target in SLE

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by a loss of tolerance to multiple endogenous antigens. SLE etiology remains largely unknown, despite recent insight into the immunopathogenesis of the disease. T cells are important in the development of the disease by amplifying the immune response and contributing to organ damage. Aberrant signaling, cytokine secretion, and tissue homing displayed by SLE T cells have been extensively studied and the underlying pathogenic molecular mechanisms are starting to be elucidated. T-cell-targeted treatments are being explored in SLE patients. This review is an update on the T-cell abnormalities and related therapeutic options in SLE.

Lessons from Sjögren’s syndrome etiopathogenesis: Novel cellular and molecular targets

Sjögren’s syndrome (SS) is a systemic autoimmune disease that affects primarily the lacrimal and salivary glands. In addition to a systemic autoimmune response directed against ubiquitous antigens (such as Ro and La antigens), patients with SS mount a localized response that affects the epithelial component of exocrine glands leading to the establishment of a destructive inflammatory infiltrate comprised of activated T and B cells. Local chemokine and cytokine production drive the recruitment and local activation of immune cells that cause injury to acinar cells. CD4 T cells with different functional differentiation programs including Th1 (IFN-γ), Th2 (IL-13, IL-4) and Th17 (IL-17, IL-21, IL-22) as well as diverse cytokine signaling pathways, are involved at the initiation, perpetuation, and progression of the disease. Which factors initiate this response and allow it to become chronic are unknown. Proposed mechanisms include viral infections and acinar cell apoptosis. Moreover risk-conferring genetic variants, probably through the facilitation of innate and adaptive immune activation, most certainly contribute to the creation of an underlying environment that fosters tolerance loss and facilitates perpetuation of the autoimmune response. In this review, we describe the mechanisms through which the immune response causes SS and emphasize the pathways that are amenable of being targeted with therapeutic purposes.

Cytokines and MicroRNAs as Candidate Biomarkers for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, with varied course and symptoms. Its etiology is very complex and not clearly understood. There is growing evidence of the important role of cytokines in SLE pathogenesis, as well as their utility as biomarkers and targets in new therapies. Other potential new SLE biomarkers are microRNAs. Recently, over one hundred different microRNAs have been demonstrated to have a significant impact on the immune system. Various alterations in these microRNAs, associated with disease pathogenesis, have been described. They influence the signaling pathways and functions of immune response cells. Here, we aim to review the emerging new data on SLE etiology and pathogenesis.

Increased Tim-3 expression on peripheral T lymphocyte subsets and association with higher disease activity in systemic lupus erythematosus

Background

Both the T cell immunoglobulin domain- and mucin domain-containing molecule-3 (Tim-3) and the death receptor Fas contribute to the pathogenesis of various autoimmune diseases, including systemic lupus erythematosus (SLE). The aim of the present study was to determine whether Tim-3 and Fas are co-expressed on certain peripheral T lymphocyte subsets, and whether this expression is associated with greater disease activity in SLE.

Methods

Peripheral blood mononuclear cells were isolated from 46 patients newly diagnosed with SLE and 28 age- and sex-matched healthy controls (HCs). Expression of Tim-3 and Fas on T subsets was analyzed by flow cytometry, while mRNA levels of the Tim-3 ligand galectin-9 and Fas ligand FasL were assayed using real-time RT-PCR.

Results

The proportions of CD3⁺CD4⁺ and CD3⁺CD4^- T cells expressing Tim-3⁺ and Tim⁺Fas⁺ were significantly higher in patients than in HCs (p < 0.05), while the proportions of these subtypes expressing Fas were similar for the two groups. Patients with active SLE, as defined by their score on the SLE Disease Activity Index, had lower proportions of CD3⁺CD4⁺ T cells and higher proportions of CD3⁺CD4⁺Tim-3⁺ and CD3⁺CD4⁺Tim-3⁺Fas⁺ T cells than did patients with stable SLE. Serum levels of complement C3 and C4 proteins, considered as a marker of SLE activity, correlated negatively with proportions of CD3⁺CD4⁺ and CD3⁺CD4^- T cells expressing Tim-3.

Conclusions

Expression of Tim-3 and co-expression of Tim-3 and Fas on certain peripheral T subsets are associated with disease activity in SLE patients. Future research should examine whether the same is true of other T subsets implicated in SLE, and should explore the potential role(s) of Tim-3 in the disease pathway.

Virtual slides

http://www.diagnosticpathology.diagnomx.eu/vs/1855527845145188