Elevated Th17 cells are accompanied by FoxP3+ Treg cells decrease in patients with lupus nephritis

Regulatory T cells in acute and chronic kidney diseases

Foxp3-expressing CD4+ regulatory T cells (Tregs) make up one subset of the helper T cells (Th) and are one of the major mechanisms of peripheral tolerance. Tregs prevent abnormal activation of the immune system throughout the lifespan, thus protecting from autoimmune and inflammatory diseases. Recent studies have elucidated the role of Tregs beyond autoimmunity. Tregs play important functions in controlling not only innate and adaptive immune cell activation, but also regulate nonimmune cell function during insults and injury. Inflammation contributes to a multitude of acute and chronic diseases affecting the kidneys. This review examines the role of Tregs in pathogenesis of renal inflammatory diseases and explores the approaches for enhancing Tregs for prevention and therapy of renal inflammation.

Increased circulating CD4+CXCR5+FoxP3+ follicular regulatory T cells correlated with severity of systemic lupus erythematosus patients

As one specialized subset of regulatory T cells (Tregs), follicular regulatory T cells (TFR) could suppress follicular helper T cells (TFH) and B cells in germinal centers to maintain immune homeostasis. The unbalance of TFR and TFH cells could result in abnormal germinal center responses and contribute to pathogenesis of autoimmune diseases. However, the role of TFR cells in systemic lupus erythematosus (SLE) remains unclear. This study revealed a significant increase of CD4⁺CXCR5⁺FOXP3⁺ TFR cells in peripheral blood of SLE patients compared with healthy controls. Meanwhile, the suppression ability of circulating TFR cells was not altered. The ratios of TFR/TFH were increased in SLE patients and the frequency of TFR was positively correlated with auto-antibodies and SLEDAI scores of SLE patients. Our results demonstrated that circulating TFR cells were increased during SLE, which suggested that elevated TFR might be a response to the pathogenesis of SLE to suppress TFH function and may provide novel insight for the pathogenesis of SLE.

Effect of induction therapy on circulating T-helper 17 and T-regulatory cells in active proliferative lupus nephritis

INTRODUCTION

T-helper 17 (Th17) cells and T-regulatory (Treg) cells have been suggested to play pathogenic roles in lupus nephritis. The in vivo effects of current therapies for lupus nephritis (LN) on these cells have not been adequately studied.

METHODS

We conducted a prospective observational study among patients with active proliferative lupus nephritis (LN) who received Eurolupus induction therapy and assessed them as per the European League Against Rheumatism criteria for renal response. Peripheral circulatory Th17 and Treg cell numbers were enumerated at start of therapy, at 3 and 6 months follow-up periods using flow cytometry. Baseline values were compared with inactive lupus patients (iSLE) and healthy controls (HC).

RESULTS

Thirty patients with LN, 20 iSLE and 22 HC were enrolled into the study. In LN, Th17 frequency was significantly higher compared to HC, and Treg frequency significantly lower compared to both iSLE and HC. Nineteen patients fulfilled criteria for response (partial or complete) at 6 months. Responder group showed a significant decline in Th17 frequency and an increasing trend in Treg frequency compared to baseline after 6 months of therapy.

CONCLUSION

Circulating Th17 cells were significantly raised in patients with active proliferative LN and showed a significant reduction in responder patients following therapy.

FOXP3+ T cells are present in kidney biopsy samples in children with tubulointerstitial nephritis and uveitis syndrome

BACKGROUND

Tubulointerstitial nephritis (TIN) is an inflammatory disease of unknown pathogenesis. To evaluate a possible role of regulatory T cells (Tregs) in the pathophysiology of TIN with (TINU) and without uveitis, we investigated the presence and quantity of FOXP3⁺ T regulatory lymphocytes in diagnostic kidney biopsies from pediatric patients.

METHODS

A total of 33 patients (14 TIN and 19 TINU) were enrolled. The quantity of CD4⁺, FOXP3⁺ and double-positive T cells in formalin-fixed kidney biopsies was determined using double label immunohistochemistry with anti-human CD4 and FOXP3 antibodies.

RESULTS

FOXP3 staining was successful in all 33 patients. In patients with chronic uveitis, the density of FOXP3⁺ cells was significantly lower (p = 0.046) than in TIN patients without uveitis or with uveitis lasting <3 months. CD4⁺ staining was successful in 23 patients. The density of all lymphocytes (CD4⁺, CD4⁺FOXP3⁺ and FOXP3⁺ cells) was significantly lower (p = 0.023) in patients with chronic uveitis than in other patients.

CONCLUSIONS

FOXP3⁺ T cells are present in kidney biopsy samples from TIN and TINU patients. In patients with chronic uveitis, the density of FOXP3⁺ T cells is significantly lower than in other patients, suggesting a different pathomechanism for these clinical conditions.

CD4+ T helper cells and regulatory T cells in active lupus nephritis: an imbalance towards a predominant Th1 response?

The objective of this study was to evaluate the frequency of CD4⁺ T cell subsets in peripheral blood mononuclear cells (PBMC), urine and renal tissue from patients with lupus nephritis (LN). PBMC and urinary cells were collected from 17 patients with active LN, 20 disease controls (DC) with primary glomerulonephritis and 10 healthy controls (HC) and were analysed by flow cytometry with markers for T helper type 1 (Th1), Th2, Th17 and regulatory T cells (T_reg ) cells. T cell subsets were assessed by immunohistochemistry from LN biopsy specimens from 12 LN patients. T cell subtypes in PBMC were re-evaluated at 6 months of therapy. CD4⁺ T cells were decreased in PBMC in LN compared with DC and HC (P = 0·0001). No differences were observed in urinary CD4⁺ T cell subsets between LN and DC. The frequency of urinary Th17 cells was higher in patients with non-proliferative than in proliferative LN (P = 0·041). CD3⁺ and T-box 21 ( Tbet+) cells were found in glomeruli and interstitium of LN patients, while forkhead box protein 3 (FoxP3), retinoid-related orphan receptor gamma (ROR-γ) and GATA binding protein 3 (GATA-3) were present only in glomeruli. Th1 cells in PBMC were correlated negatively with urinary Th1 cells (Rho = -0·531; P = 0·028) and with T_bet in renal interstitium (Rho = -0·782; P = 0·004). At 6 months, LN patients showed an increase in Th17 cells in PBMC. In conclusion, the inverse association between Th1 cells from PBMC and urinary/renal tissue indicate a role for Th1 in LN pathophysiology. Urinary Th17 cells were associated with less severe LN, and Th17 increased in PBMC during therapy. Urinary CD4⁺ T cells were not different between LN and DC.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Regulatory T cells in immune-mediated renal disease

Regulatory T cells (Tregs) are CD4+ T cells that can suppress immune responses by effector T cells, B cells and innate immune cells. This review discusses the role that Tregs play in murine models of immune-mediated renal diseases and acute kidney injury and in human autoimmune kidney disease (such as systemic lupus erythematosus, anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic antibody-associated vasculitis). Current research suggests that Tregs may be reduced in number and/or have impaired regulatory function in these diseases. Tregs possess several mechanisms by which they can limit renal and systemic inflammatory immune responses. Potential therapeutic applications involving Tregs include in vivo induction of Tregs or inducing Tregs from naïve CD4+ T cells or expanding natural Tregs ex vivo, to use as a cellular therapy. At present, the optimal method of generating a phenotypically stable pool of Tregs with long-lasting suppressive effects is not established, but human studies in renal transplantation are underway exploring the therapeutic potential of Tregs as a cellular therapy, and if successful may have a role as a novel therapy in immune-mediated renal diseases.

Emerging roles of T helper 17 and regulatory T cells in lung cancer progression and metastasis

Lung cancer is a leading cause of cancer-related deaths worldwide. Lung cancer risk factors, including smoking and exposure to environmental carcinogens, have been linked to chronic inflammation. An integral feature of inflammation is the activation, expansion and infiltration of diverse immune cell types, including CD4⁺ T cells. Within this T cell subset are immunosuppressive regulatory T (Treg) cells and pro-inflammatory T helper 17 (Th17) cells that act in a fine balance to regulate appropriate adaptive immune responses.In the context of lung cancer, evidence suggests that Tregs promote metastasis and metastatic tumor foci development. Additionally, Th17 cells have been shown to be an integral component of the inflammatory milieu in the tumor microenvironment, and potentially involved in promoting distinct lung tumor phenotypes. Studies have shown that the composition of Tregs and Th17 cells are altered in the tumor microenvironment, and that these two CD4⁺ T cell subsets play active roles in promoting lung cancer progression and metastasis.We review current knowledge on the influence of Treg and Th17 cells on lung cancer tumorigenesis, progression, metastasis and prognosis. Furthermore, we discuss the potential biological and clinical implications of the balance among Treg/Th17 cells in the context of the lung tumor microenvironment and highlight the potential prognostic function and relationship to metastasis in lung cancer.

CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) Regulatory T Cell Subsets in Mediating Autoimmune Reactivity in Systemic Lupus Erythematosus Patients

The available clinical as well as experimental studies implicate participation of T regulatory (Treg) subsets in the pathogenesis and course of systemic lupus erythematosus (SLE). Introduction of the CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) regulatory subpopulations analysis into immunological processes assessment and disease activation prognosis in patients with lupus nephritis (LN) may improve monitoring of disease activity and enable an early, and thus more effective, therapeutic treatment. The main goal of the study was to investigate whether the quantitative changes of Treg subpopulations are related to the clinical status of patients with LN. Fifty-four adult SLE patients divided into two groups according to their SLEDAI and renal SLEDAI scores were enrolled into the study. Subpopulations of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) phenotypes were determined by flow cytometry. The control group had higher absolute number of CD4(+)CD25(+)Foxp3(+) cells compared with the study group (p < 0.001). Also, significant inverse correlation in the absolute number of CD4(+)CD25(+)Foxp3(+) cells and SLEDAI score was observed. There were significant differences in the percentage and absolute number of CD4(+)CD25(+)Foxp3(+) lymphocytes between active and non-active LN groups. The study group had statistically lower values of CD4(+)CD25(+)CD127(-) cells, both in the percentage (p < 0.001) as well as their absolute number (p = 0.014) compared to the control group. There were also statistically significant positive correlations between the absolute number of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) Tregs.

IN CONCLUSION

(1) reduction in the number of regulatory CD4(+)CD25(+)Foxp3(+) cells is a promising indicator of the activity of SLE, particularly of renal involvement; (2) determination of the number of regulatory cells using the CD4(+)CD25(+)CD127(-) phenotype is unreliable in patients with SLE.

Serum Cytokines Th1, Th2, and Th17 Expression Profiling in Active Lupus Nephritis-IV: From a Southern Chinese Han Population

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by aberrant T cell immune response. Diffuse proliferative lupus nephritis (LN-IV) is the most common, severe, and active form of lupus nephritis. In this study, we investigated the production of Th1, Th2, and Th17 cytokines in prediction of active form of LN-IV. ProcartaPlex multiplex immunoassays panels were used for detection of serum Th1, Th2, and Th17 cytokines profiling. Th1 and Th17 cytokines (IL-18, IFN-γ, IL-12p70, IL-6, and IL-17A) were considerably expressed in the serum of lupus nephritis IV patients in comparison to the healthy control. However, only IL18 and IL6 were higher in class IV versus class III lupus nephritis. Importantly, the ratios of Th1/Th2 (IL-18/IL-4) and Th17/Th2 (IL-17A/IL-4) were significantly elevated in LN-IV when compared with LN-III, LN-V, and healthy controls. Consistently, the serum cytokines IL-18, IL-17A, and IFN-γ were markedly expressed in LN-IV patient glomeruli and interstitial tissue compared to other classes of LN by IHC. ROC further suggests that IL-18 was a potential marker for LN-IV. The data from our study suggests that the early detection and quantification of these cytokines may help in prediction of active form of LN-IV.

The T helper type 17/regulatory T cell paradigm in pregnancy

T helper type 17 (Th17) and regulatory T (Treg) cells are active players in the establishment of tolerance and defence. These attributes of the immune system enmesh to guarantee the right level of protection. The healthy immune system, on the one hand, recognizes and eliminates dangerous non-self pathogens and, on the other hand, protects the healthy self. However, there are circumstances where this fine balance is disrupted. In fact, in situations such as in pregnancy, the foreign fetal antigens challenge the maternal immune system and Treg cells will dominate Th17 cells to guarantee fetal survival. In other situations such as autoimmunity, where the Th17 responses are often overwhelming, the immune system shifts towards an inflammatory profile and attacks the healthy tissue from the self. Interestingly, autoimmune patients have meliorating symptoms during pregnancy. This connects with the antagonist role of Th17 and Treg cells, and their specific profiles during these two immune challenging situations. In this review, we put into perspective the Th17/Treg ratio during pregnancy and autoimmunity, as well as in pregnant women with autoimmune conditions. We further review existing systems biology approaches that study specific mechanisms of these immune cells using mathematical modelling and we point out possible future directions of investigation. Understanding what maintains or disrupts the balance between these two opponent yet reciprocal cells in healthy physiological settings, sheds light into the development of innovative pharmacological approaches to fight pregnancy loss and autoimmunity.

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect many organs, including the skin, joints, the central nervous system and the kidneys. Women of childbearing age and certain racial groups are typically predisposed to developing the condition. Rare, inherited, single-gene complement deficiencies are strongly associated with SLE, but the disease is inherited in a polygenic manner in most patients. Genetic interactions with environmental factors, particularly UV light exposure, Epstein-Barr virus infection and hormonal factors, might initiate the disease, resulting in immune dysregulation at the level of cytokines, T cells, B cells and macrophages. Diagnosis is primarily clinical and remains challenging because of the heterogeneity of SLE. Classification criteria have aided clinical trials, but, despite this, only one drug (that is, belimumab) has been approved for use in SLE in the past 60 years. The 10-year mortality has improved and toxic adverse effects of older medications such as cyclophosphamide and glucocorticoids have been partially offset by newer drugs such as mycophenolate mofetil and glucocorticoid-sparing regimes. However, further improvements have been hampered by the adverse effects of renal and neuropsychiatric involvement and late diagnosis. Adding to this burden is the increased risk of premature cardiovascular disease in SLE together with the risk of infection made worse by immunosuppressive therapy. Challenges remain with treatment-resistant disease and symptoms such as fatigue. Newer therapies may bring hope of better outcomes, and the refinement to stem cell and genetic techniques might offer a cure in the future.

Regulatory T cells in kidney disease and transplantation

Regulatory T cells (Tregs) have been shown to be important in maintaining immune homeostasis and preventing autoimmune disease, including autoimmune kidney disease. It is also likely that they play a role in limiting kidney transplant rejection and potentially in promoting transplant tolerance. Although other subsets of Tregs exist, the most potent and well-defined Tregs are the Foxp3 expressing CD4(+) Tregs derived from the thymus or generated peripherally. These CD4(+)Foxp3(+) Tregs limit autoimmune renal disease in animal models, especially chronic kidney disease, and kidney transplantation. Furthermore, other subsets of Tregs, including CD8 Tregs, may play a role in immunosuppression in kidney disease. The development and protective mechanisms of Tregs in kidney disease and kidney transplantation involve multiple mechanisms of suppression. Here we review the development and function of CD4(+)Foxp3(+) Tregs. We discuss the specific application of Tregs as a therapeutic strategy to prevent kidney disease and to limit kidney transplant rejection and detail clinical trials in this area of transplantation.

CD275-Independent IL-17-Producing T Follicular Helper-like Cells in Lymphopenic Autoimmune-Prone Mice

T cells undergo homeostatic expansion and acquire an activated phenotype in lymphopenic microenvironments. Restoration of normal lymphocyte numbers typically re-establishes normal homeostasis, and proinflammatory cytokine production returns to baseline. Mice deficient in guanine nucleotide exchange factor RasGRP1 exhibit dysregulated homeostatic expansion, which manifests as lymphoproliferative disease with autoantibody production. Our previous work revealed that autoreactive B cells lacking RasGRP1 break tolerance early during development, as well as during germinal center responses, suggesting that T cell-independent and T cell-dependent mechanisms are responsible. Examination of whether a particular T cell subset is involved in the breach of B cell tolerance revealed increased Th17 cells in Rasgrp1-deficient mice relative to control mice. Rasgrp1-deficient mice lacking IL-17R had fewer germinal centers, and germinal centers that formed contained fewer autoreactive B cells, suggesting that IL-17 signaling is required for a break in B cell tolerance in germinal centers. Interestingly, a fraction of Th17 cells from Rasgrp1-deficient mice were CXCR5(+) and upregulated levels of CD278 coordinate with their appearance in germinal centers, all attributes of T follicular helper cells (Tfh17). To determine whether CD278-CD275 interactions were required for the development of Tfh17 cells and for autoantibody, Rasgrp1-deficient mice were crossed with CD275-deficient mice. Surprisingly, mice deficient in RasGRP1 and CD275 formed Tfh17 cells and germinal centers and produced similar titers of autoantibodies as mice deficient in only RasGRP1. Therefore, these studies suggest that requirements for Tfh cell development change in lymphopenia-associated autoimmune settings.

The Changing Landscape of Renal Inflammation

Kidney inflammation is a major contributor to progressive renal injury, leading to glomerulonephritis (GN) and chronic kidney disease. We review recent advances in our understanding of leukocyte accumulation in the kidney, emphasizing key chemokines involved in GN. We discuss features of renal inflammation such as the evolving concept of immune cell plasticity. We also describe certain aspects of organ-specific tissue microenvironments in shaping immune cell responses, as well as the current knowledge of how regulatory T lymphocytes impact on other immune effector cell populations to control inflammation. It is clear that present and future research in these areas may contribute to the development of novel targeted therapeutics, with the hope of alleviating the burden of end-stage renal disease (ESRD).

Melanocortin peptides: potential targets in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease resulting in loss of self-tolerance with multiple organs, such as the kidney, skin, joints, and the central nervous system (CNS), being targeted. Numerous immunosuppressant therapies are currently being used for the treatment of SLE, but their clinical utility is somewhat variable because of the clinical heterogeneity. Melanocortins are a family of peptides derived from the common precursor protein pro-opiomelanocortin. These multifunctional peptides activate five subtypes of melanocortin receptors expressed on immune, skin, muscle, bone, and kidney cells and cells within the CNS. Melanocortin peptides have demonstrated a variety of biologic actions including immunomodulation, melanogenesis, and renoprotection. This review aims to introduce the melanocortin system and explore the mechanisms by which they may be beneficial in diseases such as SLE.

Dietary extra virgin olive oil attenuates kidney injury in pristane-induced SLE model via activation of HO-1/Nrf-2 antioxidant pathway and suppression of JAK/STAT, NF-κB and MAPK activation

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a widespread organ involvement. Recent studies have suggested that extra virgin olive oil (EVOO) might possess preventive effects on this immunoinflammation-related disease. However, its role in SLE remained unknown. In this work, we evaluated the effects of EVOO diet in a pristane-induced SLE model in mice. Three-month-old mice received an injection of pristane or saline solution and were fed with different experimental diets: sunflower oil diet or EVOO diet. After 24weeks, mice were sacrificed, spleens were collected and kidneys were removed for immunoinflammatory detections. The kidney expression of microsomal prostaglandin E synthase 1, heme oxygenase 1 (HO-1), nuclear factor E2-related factor 2 (Nrf-2), mitogen-activated protein kinases (MAPKs), Janus kinase/signal transducer and activator of transcription (JAK/STAT) and nuclear transcription factor-kappa B (NF-κB) pathways were studied by western blotting. In addition to macroscopic and histological analyses, serum matrix metalloproteinase 3 (MMP-3) levels and proinflammatory cytokines production in splenocytes were evaluated by enzyme-linked immunoassay. We have demonstrated that EVOO diet significantly reduced renal damage and decreased MMP-3 serum and PGE2 kidney levels as well as the proinflammatory cytokines production in splenocytes. Our data indicate that Nrf-2 and HO-1 protein expressions were up-regulated in those mice fed with EVOO and the activation of JAK/STAT, MAPK and NF-κB pathways were drastically ameliorated. These results support the interest of EVOO as a beneficial functional food exerting a preventive/palliative role in the management of SLE.

The involvement of T regulatory lymphocytes in a cohort of lupus nephritis patients: a pilot study

T regulator lymphocytes (Tregs) play a key role in the maintenance of immune tolerance and in the development of autoimmune diseases. Expression of Foxp3 is specific for Tregs, and can be used for the identification of these cells. This study investigated the variations of Tregs Foxp3+ in the kidney biopsies inflammatory infiltrate of different lupus nephritis classes compared to that of ANCA glomerulonephritis, acute tubulointerstitial nephritis and nephroangiosclerosis. Sections of paraffin-embedded tissue have been stained by immunohistochemistry with anti-CD3 and anti-FoxP3 antibodies. We find that the ratio of FoxP3+/CD3+ cells is significantly lower in patients with lupus nephritis class IV and in patients with vasculitides than in the course of nephroangiosclerosis, tubulointerstitial nephritis and lupus nephritis class V. The data presented herein demonstrate a decrease of FoxP3+ Treg cells in the inflammatory infiltrate of lupus nephritis, particularly during the most active phases of lupus nephritis, as observed in the course of a IV class nephritis.

Increase of peripheral T regulatory cells during remission induction with cyclophosphamide in active systemic lupus erythematosus

BACKGROUND

Cyclophosphamide efficacy in lupus nephritis (LN) and neuropsychiatric systemic lupus erythematosus (NPSLE) is probably mediated by a non-specific ablation of reactive lymphocytes. However, little is known in regard to its effect on T regulatory cells (Tregs) in such patients, which was the aim of this study.

PATIENTS AND METHODS

Ten Caucasian lupus patients were included, six with LN classes IV-V (mean age 33.8 ± 8.8 years) and four with NPSLE (mean age 35.5 ± 8.8 years, clinical manifestations: 1/4 acute confusional state, 1/4 psychosis, 2/4 refractory seizures). Cyclophosphamide was administered at monthly pulses (500 mg/m(2) /month for 6 months); doses of other administered drugs, including steroids, remained stable or lower. CD4(+) CD25(high) FOXP3(+) Tregs were assessed by flow-cytometry at baseline and before every subsequent pulse and 3-6 months after the final pulse. Disease activity was assessed by SLE Disease Activity Index (SLEDAI).

RESULTS

In LN patients, Tregs were significantly increased even after the fourth pulse (0.54 ± 0.20% vs. 1.24 ± 0.29%, P < 0.001). Likewise, in NPSLE, Tregs were significantly expanded after the fourth pulse (0.57 ± 0.23% vs. 1.41 ± 0.28%, P < 0.001). SLEDAI was significantly reduced in all patients.

CONCLUSIONS

Cyclophosphamide pulse therapy was associated with a significant increase of the CD4(+) CD25(high) FOXP3(+) Tregs in patients with active LN and NPSLE. This effect is probably indirect and may partially explain the beneficial role of cyclophosphamide in such cases.

Prognostic Significance of the Systemic Inflammatory and Immune Balance in Alcoholic Liver Disease with a Focus on Gender-Related Differences

Objectives

Mechanisms of immune regulation in alcoholic liver disease (ALD) are still unclear. The aim of our study was to determine an impact of Th17 / regulatory T (Treg) cells balance and its corresponding cytokine profile on the ALD outcome. Possible gender-related differences in the alcohol-induced inflammatory response were also assessed.

Materials and Methods

147 patients with ALD were prospectively recruited, assigned to subgroups based on their gender, severity of liver dysfunction and presence of ALD complications at admission, and followed for 90 days. Peripheral blood frequencies of Th17 and Treg cells together with IL-1beta, IL-6, IL-17A, IL-23, and TGF-beta1 levels were investigated. Flow cytometry was used to identify T cell phenotype and immunoenzymatic ELISAs for the corresponding cytokine concentrations assessment. Multivariable logistic regression was applied in order to select independent predictors of advanced liver dysfunction and the disease complications.

Results

IL-17A, IL-1beta, IL-6 levels were significantly increased, while TGF-beta1 decreased in ALD patients. The imbalance with significantly higher Th17 and lower Treg frequencies was observed in non-survivors. IL-6 and TGF-beta1 levels differed in relation to patient gender in ALD group. Concentrations of IL-6 were associated with the severity of liver dysfunction, development of ALD complications, and turned out to be the only independent immune predictor of 90-day survival in the study cohort.

Conclusions

We conclude that IL-6 revealed the highest diagnostic and prognostic potential among studied biomarkers and was related to the fatal ALD course. Gender-related differences in immune regulation might influence the susceptibility to alcohol-associated liver injury.

Distinctive Treg associated CCR4-CCL22 expression profile with altered frequency of Th17/Treg cell in the immunopathogenesis of Pemphigus Vulgaris

Pemphigus Vulgaris (PV), a relatively common autoimmune blistering disease in India, primarily mediated by anti-Desmoglein 3 (anti-Dsg3) autoantibodies. T-helper 17 (Th17) and T-regulatory (Treg) cells play significant role in regulating immune homeostasis in autoimmune disorders. To understand immunopathogenesis of PV, it is crucial to unfold the phenotypic expression and functional characteristics of these cells along with their specific homing chemokine receptor-ligand. This proposed study aims to unravel the functional expression of Th17 and Treg cells along with their specific homing chemokine receptor-ligand, transcription factors and cytokine levels to better understand the immunopathogenesis of PV. The Flow cytometry results showed decreased frequency of Treg cells and high number of Th17 cells (p<0.001) indicating immune dysregulation in PV. A significant increase (p<0.001) in the serum levels of Th17 associated molecules (IL-17A, CCL-20) and relative expression of RORγt, CCR6 and CCL20 was found in patients. For Treg cells, transcription factor FOXp3 was significantly lowered along with defective CCR4-CCL22 (p<0.05) that might be playing an ambiguous role in Treg generated immune regulation, leading to homing defect at lesional sites. This maiden study revealed the role of defective receptor-ligand interface that might have failed to suppress inflammatory milieu produced by Th17 cells thus promoting inflammation and contributing to immunopathogenesis of PV. This chemokine receptor-ligand can further be explored as potential target for development of novel therapies in PV.

The parasitic worm product ES-62 targets myeloid differentiation factor 88-dependent effector mechanisms to suppress antinuclear antibody production and proteinuria in MRL/lpr mice

Objective

The hygiene hypothesis suggests that parasitic helminths (worms) protect against the development of autoimmune disease via a serendipitous side effect of worm-derived immunomodulators that concomitantly promote parasite survival and limit host pathology. The aim of this study was to investigate whether ES-62, a phosphorylcholine-containing glycoprotein secreted by the filarial nematode Acanthocheilonema viteae, protects against kidney damage in an MRL/lpr mouse model of systemic lupus erythematosus (SLE).

Methods

MRL/lpr mice progressively produce high levels of autoantibodies, and the resultant deposition of immune complexes drives kidney pathology. The effects of ES-62 on disease progression were assessed by measurement of proteinuria, assessment of kidney histology, determination of antinuclear antibody (ANA) production and cytokine levels, and flow cytometric analysis of relevant cellular populations.

Results

ES-62 restored the disrupted balance between effector and regulatory B cells in MRL/lpr mice by inhibiting plasmablast differentiation, with a consequent reduction in ANA production and deposition of immune complexes and C3a in the kidneys. Moreover, by reducing interleukin-22 production, ES-62 may desensitize downstream effector mechanisms in the pathogenesis of kidney disease. Highlighting the therapeutic importance of resetting B cell responses, adoptive transfer of purified splenic B cells from ES-62–treated MRL/lpr mice mimicked the protection afforded by the helminth product. Mechanistically, this reflects down-regulation of myeloid differentiation factor 88 expression by B cells and also kidney cells, resulting in inhibition of pathogenic cross-talk among Toll-like receptor–, C3a-, and immune complex–mediated effector mechanisms.

Conclusion

This study provides the first demonstration of protection against kidney pathology by a parasitic worm–derived immunomodulator in a model of SLE and suggests therapeutic potential for drugs based on the mechanism of action of ES-62.

TGF-Beta Blockade Increases Renal Inflammation Caused by the C-Terminal Module of the CCN2

The CCN family member 2 (CCN2, also known as connective tissue growth factor) may behave as a risk biomarker and a potential therapeutic target for renal disease. CCN2 participates in the regulation of inflammation and fibrosis. TGF-β is considered the main fibrogenic cytokine; however, in some pathological settings TGF-β also has anti-inflammatory properties. CCN2 has been proposed as a downstream profibrotic mediator of TGF-β, but data on TGF-β role in CCN2 actions are scarce. Our aim was to evaluate the effect of TGF-β blockade in CCN2-mediated experimental renal damage. Systemic administration of the C-terminal module of CCN2 to mice caused sustained renal inflammation. In these mice, TGF-β blockade, using an anti-TGF-β neutralizing antibody, significantly increased renal expression of the NGAL (a kidney injury biomarker), kidney infiltration by monocytes/macrophages, and upregulation of MCP-1 expression. The anti-inflammatory effect of TGF-β seems to be mediated by a dysregulation of the systemic Treg immune response, shown by decreased levels of circulating CD4⁺/Foxp3⁺Treg cells. Our experimental data support the idea that TGF-β exerts anti-inflammatory actions in the kidney and suggest that it is not an optimal therapeutic target.

Pathogenesis of renal disease in systemic lupus erythematosus--the role of autoantibodies and lymphocytes subset abnormalities

Lupus nephritis (LN) is a common and severe organ manifestation of systemic lupus erythematosus (SLE), and is associated with significant patient morbidity and mortality. Autoantibodies and aberrations in lymphocyte subsets have putative roles in the pathogenesis of SLE and LN, and might reflect disease activity and are amenable to immunosuppressive treatments. Anti-DNA is one of the well-studied autoantibodies, which correlates with disease activity and has direct nephritogenic effects on resident renal cells and various glomerular components. Other important autoantibodies in the pathogenesis of LN include anti-C1q, anti-α-actinin and anti-nucleosome antibodies. Changes in naive and memory B cells and plasma cells have been observed in SLE and LN patients. These B cell subsets exert diverse effects during pathogenesis of LN such as production of autoantibodies, secretion of proinflammatory and anti-inflammatory cytokines and presentation of auto-antigens to effector cells. Aberration of T lymphocytes, especially the T-helper subsets, is also highly pertinent in the development of LN. In this context, important T helper subsets include Th1, Th2, Th9, Th17, T_Reg and follicular T-helper cells. The growing knowledge on these autoantibodies and lymphocyte subset abnormalities will enhance our understanding of SLE and LN, and hence help devise better strategies for disease monitoring and treatment.

Dysregulated CD4+ T cells from SLE-susceptible mice are sufficient to accelerate atherosclerosis in LDLr-/- mice

OBJECTIVE

Accelerated atherosclerosis is a major source of morbidity in systemic lupus erythematosus (SLE). However, the cause of SLE-accelerated atherosclerosis remains unclear.

METHODS

CD4(+) T cells from C57/Bl/6 (B6) or SLE-susceptible B6.Sle1.2.3 (B6.SLE) mice were transferred into LDLr(-/-), Rag(-/-) mice. T cells were examined for cytokine production and expression of interleukin-10 receptor (IL-10R) and functional markers. T cells were isolated based on FoxP3(GFP) expression and transferred to LDLr(-/-), Rag(-/-) mice to establish a role for B6.SLE effector T cells (Teff) in atherosclerosis.

RESULTS

Mice receiving whole B6.SLE CD4(+) T cells displayed no other SLE phenotype; however, atherosclerosis was increased nearly 40%. We noted dysregulated IL-17 production and reduced frequency of IL-10R expression by B6.SLE regulatory T cells (Treg). Functional assays indicated resistance of B6.SLE Teff to suppression by both B6.SLE and B6 Treg. Transfer experiments with CD4(+)FoxP3(-) Teff and CD4(+)FoxP3(+) Treg from B6.SLE and B6 mice, respectively, resulted in increased atherosclerosis compared with B6 Teff and Treg recipients. Treg isolated from mice receiving B6.SLE Teff with B6 Treg had increased production of IL-17 and fewer expressed IL-10R compared with B6 Teff and Treg transfer.

CONCLUSIONS

Transfer of B6.SLE Teff to LDLr(-/-), Rag(-/-) mice results in accelerated atherosclerosis independent of the source of Treg. In addition, the presence of B6.SLE Teff resulted in more IL-17-producing Treg and fewer expressing IL-10R, suggesting that B6.SLE Teff may mediate phenotypic changes in Treg. To our knowledge, this is the first study to provide direct evidence of the role of B6.SLE Teff in accelerating atherosclerosis through resistance to Treg suppression.

Jieduquyuziyin prescription suppresses IL-17 production and Th17 activity in MRL/lpr mice by inhibiting expression of Ca(2+)/calmodulin-dependent protein kinase-4

Jieduquyuziyin prescription (JP) is a traditional Chinese medicinal (TCM) formula which has been demonstrated to be effective for systemic lupus erythematosus (SLE) treatment as an approved hospital prescription for many years in China. But its mechanism of action in combating this disease is largely unknown. Our previous studies showed that JP can slow disease progression without producing significant toxic side effects. We treated MRL/lpr mice with JP to ascertain if JP could improve SLE by the suppression of Ca(2+)/calmodulin-dependent protein kinase-4 (CaMK4) expression. We investigated the role of JP in a model of SLE in MRL/lpr mice, and identified the possible mechanism of action. Mice were divided randomly into four groups: control, model, and two treatment groups. Sections of renal tissue were stained with hematoxylin and eosin (H&E). Histopathologic changes in the kidney were evaluated by light microscopy. T-helper (Th)17 cells were analyzed by flow cytometry. mRNA levels of interleukin (IL)-17, CaMK4, and RORγt were measured by reverse transcription polymerase chain reaction (RT-PCR). CaMK4 expression was assessed by Western blotting. The results showed that the percentages of Th17, IL-17, and RORγt in mice treated with JP were decreased remarkably compared to the model group (p < 0.05). Interestingly, a high CaMK4 expression was observed in the SLE mice, which was inhibited by JP. These results suggest that CaMK4 activity was increased in T cells from MRL/lpr mice compared with the control group. Our findings support the conclusion that the effects of JP on MRL/lpr mice may involve the regulation of CaMK4 overexpression in MRL/lpr mice.

Th17 cells in autoimmune diseases

Th17 cells are a new subset of CD4(+) T cells involved in the clearance of extracellular pathogens and fungi. Accumulating evidence suggests that Th17 cells and their signature cytokines have a pivotal role in the pathogenesis of multiple autoimmune-mediated inflammatory diseases. Here, we summarize recent research progress on Th17 function in the development and pathogenesis of autoimmune diseases. We also propose to identify new small molecule compounds to manipulate Th17 function for potential therapeutic application to treat human autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, inflammatory bowel disease, and multiple sclerosis.

Low-dose interleukin-2 therapy: a driver of an imbalance between immune tolerance and autoimmunity

For many years, the role of interleukin-2 (IL-2) in autoimmune responses was established as a cytokine possessing strong pro-inflammatory activity. Studies of the past few years have changed our knowledge on IL-2 in autoimmune chronic inflammation, suggesting its protective role, when administered at low-doses. The disrupted balance between regulatory and effector T cells (Tregs and Teffs, respectively) is a characteristic of autoimmune diseases, and is dependent on homeostatic cytokines, including IL-2. Actually, inherent defects in the IL-2 signaling pathway and/or levels leading to Treg compromised function and numbers as well as Th17 expansion have been attributed to autoimmune disorders. In this review, we discuss the role of IL-2 in the pathogenesis of autoimmune diseases. In particular, we highlight the impact of the dysregulated IL-2 pathway on disruption of the Treg/Th17 balance, reversal of which appears to be a possible mechanism of the low-dose IL-2 treatment. The negative effects of IL-2 on the differentiation of follicular helper T cells (Tfh) and pathogenic Th17 cells, both of which contribute to autoimmunity, is emphasized in the paper as well. We also compare the current IL-2-based therapies of animal and human subjects with immune-mediated diseases aimed at boosting the Treg population, which is the most IL-2-dependent cell subset desirable for sufficient control of autoimmunity. New perspectives of therapeutic approaches focused on selective delivery of IL-2 to inflamed tissues, thus allowing local activity of IL-2 to be combined with its reduced systemic and pleiotropic toxicity, are also proposed in this paper.

Piperlongumine alleviates lupus nephritis in MRL-Fas(lpr) mice by regulating the frequency of Th17 and regulatory T cells

Recent data have shown that piperlongumine (PL), an important component of Piper longum fruits, is known to possess anti-inflammatory and vascular-protective activities. This study aimed to examine the therapeutic effects and underlying mechanisms of PL on lupus-prone MRL-Fas(lpr) mice. Female MRL-Fas(lpr) mice were intraperitoneally treated with PL (2.4 mg kg(-1) d(-1)) for 10 weeks, and the proteinuria level was biweekly monitored. After the mice were euthanized, serum biochemical parameters and renal damage were determined. Splenocytes of MRL-Fas(lpr) mice were isolated for in vitro study. Treatment of the mice with PL significantly attenuated the progression of proteinuria and glomerulonephritis. The improvement was accompanied by decreased serum levels of nephritogenic anti-dsDNA antibodies, IL-6, IL-17, IL-23 and TNF-α. Treatment of the mice with PL suppressed the frequency of Th17 cells and increased the regulatory T cells (Tregs). In vitro, the levels of IL-6, IL-17, IL-23 and TNF-α were significantly decreased in the cultures of splenocytes from PL-treated mice compared with those from vehicle-treated mice. In addition, PL treatment impeded activation of the JAK/STAT3 signaling in splenocytes. Of great important, the survival of MRL-Fas(lpr) mice were improved by PL treatment. In summary, PL effectively ameliorates lupus syndrome in MRL-Fas(lpr) mice by suppressing the pathogenic Th17 cells and increasing the Tregs as well as inhibiting activation of the JAK/STAT3 signaling pathway. This study sheds new light on the immune-modulatory role of PL.

Th17 cells in autoimmune and infectious diseases

The view of CD4 T-cell-mediated immunity as a balance between distinct lineages of Th1 and Th2 cells has changed dramatically. Identification of the IL-17 family of cytokines and of the fact that IL-23 mediates the expansion of IL-17-producing T cells uncovered a new subset of Th cells designated Th17 cells, which have emerged as a third independent T-cell subset that may play an essential role in protection against certain extracellular pathogens. Moreover, Th17 cells have been extensively analyzed because of their strong association with inflammatory disorders and autoimmune diseases. Also, they appear to be critical for controlling these disorders. Similar to Th1 and Th2 cells, Th17 cells require specific cytokines and transcription factors for their differentiation. Th17 cells have been characterized as one of the major pathogenic Th cell populations underlying the development of many autoimmune diseases, and they are enhanced and stabilized by IL-23. The characteristics of Th17 cells, cytokines, and their sources, as well as their role in infectious and autoimmune diseases, are discussed in this review.

Impaired balance of T helper 17/T regulatory cells in carbon tetrachloride-induced liver fibrosis in mice

AIM: To investigate the effect of T helper (Th) 17/T regulatory (Treg) cells on hepatic fibrosis in mice and its possible mechanism.

METHODS: Hepatic fibrosis was induced by intraperitoneal injection of carbon tetrachloride. Hepatic pathological changes were observed by hematoxylin and eosin staining; the protein levels of interleukin (IL)-6, transforming growth factor (TGF)-β and α-smooth muscle actin (SMA) in liver tissue were determined by Western blotting; and the frequency of Th17 and Treg cells in the liver was estimated by flow cytometry. In addition, hepatic stellate cells were isolated from healthy mouse liver and co-cultured with Th17 or Treg cells. Immunofluorescence staining and Western blotting were performed to determine the change in HSC activation.

RESULTS: In the model group, there were different degrees of fibroplasia, degeneration and necrosis. The protein levels of IL-6, TGF-β and α-SMA in liver tissue were significantly higher than those in the control group at 12 wk (P < 0.05). Compared with the control group, the frequency of Th17 cells in the model group was increased but the frequency of Treg cells decreased gradually. Furthermore, at 4, 8 and 12 wk, there were significant differences in the number of Th17 cells (0.52% ± 0.16%, 1.46% ± 0.24%, and 2.60% ± 0.41%, respectively, P < 0.05) and Treg cells (2.99% ± 0.40%, 2.16% ± 0.50%, and 1.49% ± 0.34%, respectively, P < 0.05). In vitro, Th17 cells promoted, whereas Treg cells inhibited the expression of α-SMA, both in a dose-dependent manner, compared with the control group.

CONCLUSION: Th17/Treg imbalance exists in mice with liver fibrosis, which potentially promotes liver fibrosis via HSC activation.

The pro-inflammatory potential of T cells in juvenile-onset systemic lupus erythematosus

BACKGROUND

T cells are important to systemic lupus erythematosus (SLE) disease progression. This study determined the pro-inflammatory potential of T cells within the rare condition juvenile-onset SLE (JSLE).

METHOD

IL-17A and Th1/Th2-related cytokine concentrations were measured in plasma/serum from JSLE patients (n = 19, n = 11) and HC (n = 18, n = 7). IL17A, RORC, IL23 and IL23R mRNA were measured in peripheral blood mononuclear cells (PBMCs) from JSLE and healthy controls (HC) (n = 12). Th17-associated cytokine expression was analysed in the supernatant of CD3/CD28 activated JSLE (n = 7) and HC (n = 6) PBMCs.

RESULTS

JSLE plasma IL-17A level (21.5 ± 5.2 pg/ml) was higher compared to HC (7.2 ± 2.5 pg/ml, p = 0.028). No differences were found in Th1/Th2 cytokines levels. IL = 17A (p = 0.022), IL-6 (p = 0.028) and IL-21 (p = 0.003) concentrations were increased in supernatants from activated JSLE PBMCs. IL-17 F (p = 0.50) and IL-22 (p = 0.43) were also increased but were not statistically significant. IL17A and IL23 mRNA was significantly higher in JSLE PBMCs (p = 0.018 and p = 0.01).

CONCLUSION

JSLE T cells have an increased ability to secrete Th17 associated cytokines once activated, which could contribute to the pro-inflammatory disease phenotype seen in these patients.

Imbalance between Th17 and regulatory T-Cells in sarcoidosis

Sarcoidosis is a systemic granulomatous disease, which is thought to result from an aberrant immune response. CD4+ T lymphocytes play an important role in the development of granulomas. Previously, the immunopathogenesis of sarcoidosis was focused on Th1/Th2 disturbances. The aim of this study was to evaluate the balance between newer CD4+ T lymphocytes, i.e., Treg and Th17 cells. In our studies, a decrease in Treg cells and an increase in Th17 cells were observed in the peripheral blood and BALF of sarcoidosis patients. A significant increase in the Th17/Treg cell ratio was observed in sarcoidosis patients. After treatment with prednisone, the expression of Foxp3 mRNA was elevated in the peripheral blood, and expression of (ROR)γt mRNA showed a downward trend. These findings suggest that sarcoidosis is associated with an imbalance between Th17 and Treg cells in peripheral blood and BALF. Therefore, targeting the cytokines that affect the Th17/Treg ratio could provide a new promising therapy for pulmonary sarcoidosis.

Th17/Treg imbalance induced by increased incidence of atherosclerosis in patients with systemic lupus erythematosus (SLE)

The objective of the study was to investigate whether the immunological factors in patients with Systemic Lupus Erythematosus (SLE) and a high incidence of atherosclerosis correlate with a Th17/Treg imbalance. All cases were recruited from the Affiliated Hospital of Guilin Medical University: a random sample of 42 cases with SLE and atherosclerosis, 39 positive control cases with SLE alone with no anomalies detected via coronary artery angiography or carotid color Doppler ultrasound examination, as well as 45 normal controls based on physical examination were included. The serum expression levels of IL-10, IL-17, IL-6, TNF-α, Th17, Th17 cell transcription factor RORγt, and Treg cell transcription factor Foxp3 were measured in each group of patients. Correlations among Th17/Treg, their secreted cell factors, transcription factors, SLE, and SLE with concurrent atherosclerosis (SLE + AS) were analyzed. The results are as follows: (1) total cholesterol and triacylglycerol levels in the SLE and SLE + AS groups were higher than those in the control group (P < 0.05 and P < 0.01); (2) serum IL-10 in the SLE + AS group was lower than the SLE and control groups; however, serum IL-17 and IL-6 levels in the SLE + AS group were elevated compared to the SLE and control groups (average P < 0.01); (3) the percentage of Treg cells in the SLE + AS patients was lower than those found in the SLE and control groups; in contrast, percentages of serum Th17 cells in SLE + AS patients were higher than the SLE and control groups (average P < 0.01); (4) FoxP3 expression in the SLE + AS group was lower than levels observed in the SLE and control groups (average P < 0.05); in contrast, RORγt expression in the SLE + AS group was higher than levels found in the SLE and control groups (average P < 0.05). The abnormal balance between Th17 cells and Treg cells in SLE + AS patients has obvious implications for Th17 migration. The results suggest that Th17 cell proportion and function can be enhanced, relatively or absolutely, whereas the proportion and function of Treg cells can abate, relatively or absolutely. This imbalance may be an important reason for the high incidence of SLE with atherosclerosis.

Interleukin-17 expression positively correlates with disease severity of lupus nephritis by increasing anti-double-stranded DNA antibody production in a lupus model induced by activated lymphocyte derived DNA

Lupus nephritis is one of the most serious manifestations and one of the strongest predictors of a poor outcome in systemic lupus erythematosus (SLE). Recent evidence implicated a potential role of interlukin-17 (IL-17) in the pathogenesis of lupus nephritis. However, the correlation between IL-17 expression level and the severity of lupus nephritis still remains incompletely understood. In this study, we found that serum IL-17 expression level was associated with the severity of lupus nephritis, which was evaluated by histopathology of kidney sections and urine protein. Of note, we showed that enforced expression of IL-17 using adenovirus construct that expresses IL-17 could enhance the severity of lupus nephritis, while blockade of IL-17 using neutralizing antibody resulted in decreased severity of lupus nephritis. Consistently, we observed an impaired induction of lupus nephritis in IL-17-deficient mice. Further, we revealed that IL-17 expression level was associated with immune complex deposition and complement activation in kidney. Of interest, we found that IL-17 was crucial for increasing anti-double-stranded DNA (dsDNA) antibody production in SLE. Our results suggested that IL-17 expression level positively correlated with the severity of lupus nephritis, at least in part, because of its contribution to anti-dsDNA antibody production. These findings provided a novel mechanism for how IL-17 expression level correlated with disease pathogenesis and suggested that management of IL-17 expression level was a potential and promising approach for treatment of lupus nephritis.

IFN-γ induces lipogenesis in mouse mesangial cells via the JAK2/STAT1 pathway

The objective is to investigate the effect of high mobility group box-1 (HMGB1) on lipid deposition in γ-interferon (IFN-γ)-stimulated mouse mesangial cell line (MMC) and to determine whether the Janus kinase 2 and signal transducer and activator of transcription 1 (JAK2/STAT1) signaling pathway plays an important role in this process. We employed a control group, an IFN-γ stimulation group, and an IFN-γ + AG490 (JAK2 inhibitor) group. RNA interference aimed at sterol regulatory element-binding protein-1 (SREBP-1) or HMGB1 was used to investigate the effect of these proteins on IFN-γ-induced lipid deposition. Western blotting was used to detect phospho (p)-JAK2, JAK2, p-STAT1, STAT1, SREBP-1, fatty acid synthase (FAS), and HMGB1 protein expression. RT-PCR was used to detect SREBP-1, FAS, and HMGB1 mRNA. Oil Red O staining and the triglyceride assay were used to detect lipid deposition and triglyceride content. Results were as follows: 1) IFN-γ increased MMC cell lipid deposition, triglyceride content, and p-JAK2, p-STAT1, SREBP-1, and FAS expression; 2) SREBP-1 inhibition prevented FAS upregulation and attenuated IFN-γ-induced MMC cell lipid deposition and triglyceride content; 3) HMGB1 upregulated SREBP-1 and FAS mRNA and protein levels, which increased lipid deposition in MMC cells. Small interfering RNA-mediated inhibition of HMGB1 decreased SREBP-1 and FAS expression and lipid accumulation; 4) AG490 decreased upregulation of HMGB1 and p-JAK2/p-STAT1, as well as IFN-γ-induced lipogenesis. In conclusion, the JAK2/STAT1 pathway mediates IFN-γ-induced lipogenesis in MMC cells through regulation of HMGB1/SREBP-1/FAS.

Altered AKT1 and MAPK1 gene expression on peripheral blood mononuclear cells and correlation with T-helper-transcription factors in systemic lupus erythematosus patients

Kinases have been implicated in the immunopathological mechanisms of Systemic Lupus Erythematosus (SLE). v-akt murine-thymoma viral-oncogene-homolog 1 (AKT1) and mitogen-activated-protein-kinase 1 (MAPK1) gene expressions in peripheral mononuclear cells from thirteen SLE patients with inactive or mild disease were evaluated using quantitative real-time reverse-transcription polymerase-chain-reaction and analyzed whether there was any correlation with T-helper (Th) transcription factors (TF) gene expression, cytokines, and S100A8/S100A9-(Calprotectin). Age- and gender-matched thirteen healthy controls were examined. AKT1 and MAPK1 expressions were upregulated in SLE patients and correlated with Th17-(Retinoic acid-related orphan receptor (ROR)-C), T-regulatory-(Treg)-(Transforming Growth Factor Beta (TGFB)-2), and Th2-(interleukin (IL)-5)-related genes. MAPK1 expression correlated with Th1-(IL-12A, T-box TF-(T-bet)), Th2-(GATA binding protein-(GATA)-3), and IL-10 expressions. IL-10 expression was increased and correlated with plasma Tumor Necrosis Factor (TNF)-α and Th0-(IL-2), Th1-(IL-12A, T-bet), GATA3, Treg-(Forkhead/winged-helix transcription factor- (FOXP)-3), and IL-6 expressions. FOXP3 expression, FOXP3/RORC, and FOXP3/GATA3 expression ratios were increased. Plasma IL-1β, IL-12(p70), Interferon-(IFN)-γ, and IL-6 cytokines were augmented. Plasma IL-1β, IL-6, IL-2, IFN-γ, TNF-α, IL-10, and IL-13 correlated with C-reactive protein, respectively. Increased Calprotectin correlated with neutrophils. Conclusion, SLE patients presented a systemic immunoinflammatory activity, augmented AKT1 and MAPK1 expressions, proinflammatory cytokines, and Calprotectin, together with increased expression of Treg-related genes, suggesting a regulatory feedback opposing the inflammatory activity.

Accelerated atherosclerosis in SLE: mechanisms and prevention approaches

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by increased serum autoantibody levels and tissue damage. With improved diagnosis and more effective treatment of the resultant kidney disease, accelerated atherosclerosis has become a major cause of morbidity in patients suffering from SLE. Although the exact mechanisms for SLE-accelerated atherosclerosis are unknown, multiple factors have been established as potential players in this process. Among these potential players are dysregulation of T and B cell populations and increased circulating levels of inflammatory cytokines. In addition, SLE patients exhibit a proatherogenic lipid profile characterized by low HDL and high LDL and triglycerides. Recent therapeutic approaches have focused on targeting B cells, the producers of autoantibodies, but most studies do not consider the effects of these treatments on atherosclerosis. Evidence suggests that T cells play a major role in SLE-accelerated atherosclerosis. Therefore, therapies targeted at T cells may also prove invaluable in treating SLE and atherosclerosis.

Relationship between FOXP3 positive populations and cytokine production in systemic lupus erythematosus

In this work we studied CD4+FOXP3+ populations in systemic lupus erythematosus (SLE) and the relationship with Th cytokine production. We found an increment in CD25-FOXP3+ population in SLE associated with CD4+ downregulation and disease progression. CD25low cells were also upregulated and showed increased percentages of FOXP3+ and CD127-/low cells, supporting the activated status of SLE lymphocytes. Despite the normal levels of CD25highFOXP3+ cells, the negative correlations observed in controls with the frequency of IFNγ, TNFα and IL-10 secreting cells were disrupted in patients, supporting a defective Treg function. Also, CD25high cells showed an altered balance in the production of these cytokines. In addition, CD25highFOXP3+ cells correlated directly with IL-17A and IL-8 but not with TGFβ in SLE. The increased proportion of IL-17+ cells among the CD25high subset and the positive correlation between IL-17 levels and Treg cells suggest a trans-differentiation of Treg into Th17 cells in SLE.

The potential role of Th17 cells and Th17-related cytokines in the pathogenesis of lupus nephritis

T helper type 17 (Th17) cells, a novel distinct subset of Th cell, can secrete interleukin (IL)-17 in humans. Although recent data suggest that Th17 cells and IL-17 play an important role in the pathogenesis of lupus nephritis (LN), the expression of Th17-related cytokines in the kidneys of SLE patients has not been studied in detail. In the present study, we investigated circulating Th17-cell frequencies using flow cytometry and serum Th17-related cytokine levels by enzyme-linked immunosorbent assay (ELISA) in 24 LN patients (17 patients with class IV and seven patients with class V) and 12 healthy controls. We also investigated glomerular Th17-related cytokine expression in LN patients and minimal change nephropathy (MCN) patients using immunohistochemistry. Our results showed significantly higher median frequencies of circulating Th17 cells in LN patients (0.68%) than in healthy controls (0.12%, p < 0.001). Serum levels of IL-17, IL-6 and IL-23 were significantly higher in LN patients (median 7.26, 232.60 and 37.01 pg/ml, respectively) than in healthy controls (median 0.82, 34.60 and 7.42 pg/ml, respectively; all p < 0.001). Circulating Th17-cell frequencies were positively correlated with SLEDAI, renal SLEDAI and histological activity index, the degree of cellular crescent and endocapillary proliferation. Significantly higher levels of glomerular IL-17 and IL-23 expression were observed in renal biopsies from class IV LN patients as compared to those from MCN patients and normal controls. Glomerular IL-17 and IL-23 expression levels were positively correlated with renal SLEDAI and histological activity index for LN patients. Our results suggest the potential role of the IL-23/Th17 axis in the intra-renal inflammation of SLE.

Balance between regulatory T and Th17 cells in systemic lupus erythematosus: the old and the new

Pathogenic mechanisms underlying the development of systemic lupus erythematosus (SLE) are very complex and not yet entirely clarified. However, the pivotal role of T lymphocytes in the induction and perpetuation of aberrant immune response is well established. Among T cells, IL-17 producing T helper (Th17) cells and regulatory T (Treg) cells represent an intriguing issue to be addressed in SLE pathogenesis, since an imbalance between the two subsets has been observed in the course of the disease. Treg cells appear to be impaired and therefore unable to counteract autoreactive T lymphocytes. Conversely, Th17 cells accumulate in target organs contributing to local IL-17 production and eventually tissue damage. In this setting, targeting Treg/Th17 balance for therapeutic purposes may represent an intriguing and useful tool for SLE treatment in the next future. In this paper, the current knowledge about Treg and Th17 cells interplay in SLE will be discussed.

Effector T-cell subsets in systemic lupus erythematosus: update focusing on Th17 cells

PURPOSE OF REVIEW

The discovery of T helper (Th)17 cells that produce the proinflammatory cytokine IL-17 has substantially advanced our understanding of T-cell biology and autoimmunity. We will review recent findings on effector T cells, in particular Th17 cells, in lupus.

RECENT FINDINGS

Studies reported increased IL-17 levels in the circulation and tissues in human and murine lupus. Patients with systemic lupus erythematosus (SLE or lupus) had an increased frequency of Th17 cells in peripheral blood which correlated with disease activity. However, the frequency of IFN-γ-producing Th1 cells did not change in the same patients, suggesting a selective dysregulation of Th17 cells in SLE. In addition, patients with SLE had an increased frequency of IL-17-producing CD3CD4CD8 (double negative) T cells in the peripheral blood and kidneys. Similar findings were noticed in lupus-prone MRL/MP-lpr/lpr (MRL/lpr) mice. A recent study demonstrated that IL-17 could promote B-cell survival and differentiation into antibody-producing cells. This raises the possibility that IL-17 is implicated in the pathogenesis of SLE by promoting humoral immunity against self-antigen.

SUMMARY

Emerging data show a body of evidence that IL-17 and Th17 cells may play a role in the pathogenesis of SLE. Further studies are warranted to dissect the mechanism for increased IL-17 production and the therapeutic implication of targeting this cytokine in SLE.