Down-regulation of survivin alleviates experimental arthritis

Single-Cell Analysis of CX3CR1+ Cells Reveals a Pathogenic Role for BIRC5+ Myeloid Proliferating Cells Driven by Staphylococcus aureus Leukotoxins

Our previous studies identified a population of stem cell-like proliferating myeloid cells within inflamed tissues that could serve as a reservoir for tissue macrophages to adopt different activation states depending on the microenvironment. By lineage-tracing cells derived from CX3CR1+ precursors in mice during infection and profiling by single-cell RNA sequencing, in this study, we identify a cluster of BIRC5+ myeloid cells that expanded in the liver during chronic infection with either the parasite Schistosoma mansoni or the bacterial pathogen Staphylococcus aureus. In the absence of tissue-damaging toxins, S. aureus infection does not elicit these BIRC5+ cells. Moreover, deletion of BIRC5 from CX3CR1-expressing cells results in improved survival during S. aureus infection. Hence the combination of single-cell RNA sequencing and genetic fate-mapping CX3CR1+ cells revealed a toxin-dependent pathogenic role for BIRC5 in myeloid cells during S. aureus infection.

Increase in serum vimentin levels in patients with glioma and its correlation with prognosis of patients with glioblastoma

Early diagnosis of glioma is of great value to improve prognosis. We focused on serum vimentin levels as a useful biomarker for preoperative diagnosis. The aim of this study was to determine whether serum vimentin levels in patients with glioma are significantly higher than those of healthy adult volunteer and whether the serum vimentin level is associated with overall survival (OS) in patients with glioblastoma (GBM). This study included 52 consecutive patients with newly diagnosed glioma and a control group of 13 healthy adult volunteers. We measured serum vimentin levels in blood samples obtained from patients with glioma preoperatively and a control group. Furthermore, we investigated the correlation between serum vimentin levels and OS in patients with GBM. The serum vimentin levels of patients with glioma were significantly higher than those of the control group. The serum vimentin level of 2.9 ng/ml was the optimal value for differentiating patients with glioma from the control group with a sensitivity of 92.3% and specificity of 88.5%. The serum vimentin levels correlated significantly with immunoreactivity for survivin. In 27 patients with GBM, serum vimentin levels (cutoff value, median value 53.3 ng/ml) correlated with OS in univariate and multivariate analyses. Our study revealed that serum vimentin levels of patients with glioma are significantly higher than those of the control group. Therefore, we believe that serum vimentin level might be a useful and practical biomarker for preoperative diagnosis of glioma. Furthermore, high serum vimentin levels correlated significantly with shorter OS in patients with GBM.

Immunomodulatory Microparticles Epigenetically Modulate T Cells and Systemically Ameliorate Autoimmune Arthritis

Disease modifying antirheumatic drugs (DMARDs) have improved the prognosis of autoimmune inflammatory arthritides but a large fraction of patients display partial or nonresponsiveness to front-line DMARDs. Here, an immunoregulatory approach based on sustained joint-localized release of all-trans retinoic acid (ATRA), which modulates local immune activation and enhances disease-protective T cells and leads to systemic disease control is reported. ATRA imprints a unique chromatin landscape in T cells, which is associated with an enhancement in the differentiation of naïve T cells into anti-inflammatory regulatory T cells (Treg ) and suppression of Treg destabilization. Sustained release poly-(lactic-co-glycolic) acid (PLGA)-based biodegradable microparticles encapsulating ATRA (PLGA-ATRA MP) are retained in arthritic mouse joints after intra-articular (IA) injection. IA PLGA-ATRA MP enhance migratory Treg which in turn reduce inflammation and modify disease in injected and uninjected joints, a phenotype that is also reproduced by IA injection of Treg . PLGA-ATRA MP reduce proteoglycan loss and bone erosions in the SKG and collagen-induced arthritis mouse models of autoimmune arthritis. Strikingly, systemic disease modulation by PLGA-ATRA MP is not associated with generalized immune suppression. PLGA-ATRA MP have the potential to be developed as a disease modifying agent for autoimmune arthritis.

Single-cell analysis of CX3CR1 + cells reveal a pathogenic role for BIRC5 + myeloid proliferating cells driven by Staphylococcus aureus leukotoxins

Our previous studies identified a population of stem cell-like proliferating myeloid cells within inflamed tissues that could serve as a reservoir for tissue macrophages to adopt different activation states depending on the microenvironment. By lineage tracing cells derived from CX3CR1 + precursors in mice during infection and profiling by scRNA-seq, here we identify a cluster of BIRC5 + myeloid cells that expanded in the liver during either chronic infection with the parasite Schistosoma mansoni or the bacterial pathogen Staphylococcus aureus . In the absence of tissue damaging toxins, S. aureus infection does not elicit these BIRC5 + cells. Moreover, deletion of BIRC5 from CX3CR1 expressing cells results in improved survival during S. aureus infection. Hence, the combination of scRNA-Seq and genetic fate mapping CX3CR1 + cells revealed a toxin dependent pathogenic role for BIRC5 in myeloid cells during S. aureus infection.

Contribution of survivin to the immune system, allergies and autoimmune diseases

In addition to malignancies, survivin (a member of the apoptosis inhibitor family) has been implicated in the pathogenesis of inflammatory disorders, including autoimmune and allergic diseases. Survivin is constantly expressed in the proliferating hematopoietic progenitor cells, and it is re-expressed in the mature cells of the innate and adaptive immunity, upon activation. Survivin enhances the expression of co-stimulatory molecules and MHC class II molecules in dendritic cells, and promotes the lifespan of macrophages, neutrophils, and eosinophils, while suppressing natural killer (NK) cell activity. Survivin has been implicated in T cell maturation, T cell expansion, effector CD4⁺ T cell differentiation, maintenance of memory CD4⁺ T and CD8⁺ T cells, as well as antibody production. Upregulated expression of survivin was indicated in the T cells as well as various samples collected from allergic patients. Survivin can contribute to the pathogenesis of allergic diseases via the promotion of the Th2 polarization, promoting IL-4 expression, compromising activation-induced cell death (AICD) in Th2 cells, and preventing apoptosis of eosinophils, as well as, amplification of eosinophilia. Moreover, survivin can interfere with clonal deletion of autoreactive T and B cells, as well as suppress Treg cell development and activity supporting the development of autoimmune diseases. This review discusses the role of survivin in immunity, allergy and autoimmunity as well as provides evidence that survivin may be considered as a novel therapeutic target for the treatment of allergic and autoimmune diseases.

SMOC2 promotes aggressive behavior of fibroblast-like synoviocytes in rheumatoid arthritis through transcriptional and post-transcriptional regulating MYO1C

Fibroblast-like synoviocytes (FLSs), play a key role in perpetuating synovial inflammation and bone erosion in rheumatoid arthritis (RA), however, the underlying mechanism(s) of RA FLSs activation and aggression remain unclear. Identifying endogenous proteins that selectively target FLSs is urgently needed. Here, we systematically identified that secreted modular calcium-binding protein 2 (SMOC2), was significantly increased in RA FLSs and synovial tissues. SMOC2 knockdown specifically regulated cytoskeleton remodeling and decreased the migration and invasion of RA FLSs. Mechanistically, cytoskeleton-related genes were significantly downregulated in RA FLSs with reduced SMOC2 expression, especially the motor protein myosin1c (MYO1C). SMOC2 controlled MYO1C expression by SRY-related high-mobility group box 4 (SOX4) and AlkB homolog 5 (ALKHB5) mediated-m⁶A modification through transcriptional and post-transcriptional regulation. Furthermore, intra-articular Ad-shRNA-SMOC2 treatment attenuated synovial inflammation as well as bone and cartilage erosion in rats with collagen-induced arthritis (CIA). Our findings suggest that increased SMOC2 expression in FLSs may contribute to synovial aggression and joint destruction in RA. SMOC2 may serve as a potential target against RA. SMOC2-mediated regulation of the synovial migration and invasion in RA FLSs. In RA FLSs, SMOC2 is significantly increased, leading to the increased level of MYO1C via SOX4-mediated transcriptional regulation and ALKBH5-mediated m⁶A modification, thereby causing cytoskeleton remodeling and promoting RA FLSs migration and invasion. The Figure was drawn by Figdraw.

Rho-GTPase dependent leukocyte interaction generates pro-inflammatory thymic Tregs and causes arthritis

Conditional mutation of protein geranylgeranyltransferase type I (GGTase-I) in macrophages (GLC) activates Rho-GTPases and causes arthritis in mice. Knocking out Rag1 in GLC mice alleviates arthritis which indicates that lymphocytes are required for arthritis development in those mice. To study GLC dependent changes in the adaptive immunity, we isolated CD4⁺ T cells from GLC mice (CD4⁺GLCs). Spleen and joint draining lymph nodes (dLN) CD4⁺GLCs exhibited high expression of Cdc42 and Rac1, which repressed the caudal HOXA proteins and activated the mechanosensory complex to facilitate migration. These CDC42/RAC1 rich CD4⁺GLCs presented a complete signature of GARP⁺NRP1⁺IKZF2⁺FOXP3⁺ regulatory T cells (Tregs) of thymic origin. Activation of the β-catenin/Lef1 axis promoted a pro-inflammatory Th1 phenotype of Tregs, which was strongly associated with arthritis severity. Knockout of Cdc42 in macrophages of GLC mice affected CD4⁺ cell biology and triggered development of non-thymic Tregs. Knockout of Rac1 and RhoA had no such effects on CD4⁺ cells although it alleviated arthritis in GLC mice. Disrupting macrophage and T cell interaction with CTLA4 fusion protein reduced the Th1-driven inflammation and enrichment of thymic Tregs into dLNs. Antigen challenge reinforced the CD4⁺GLC phenotype in non-arthritic heterozygote GLC mice and increased accumulation of Rho-GTPase expressing thymic Tregs in dLNs. Our study demonstrates an unexpected role of macrophages in stimulating the development of pro-inflammatory thymic Tregs and reveal activation of Rho-GTPases behind their arthritogenic phenotype.

Ablation of Survivin in T Cells Attenuates Acute Allograft Rejection after Murine Heterotopic Heart Transplantation by Inducing Apoptosis

Although studies in oncology have well explored the pharmacological effects of Birc5, little is known about its role in allogeneic T-cell responses. Therefore, the present study used a mouse model of acute heart allograft rejection to investigate the protective effect and mechanism of conditional knockout of Birc5 in T cells. Survivin (encoded by Birc5) was up-regulated in T cells activated in vivo and in vitro. Deletion of Birc5 in T cells attenuated acute heart allograft rejection by reducing the ratio of effector to naive T cells and Th1 to Tregs. In addition, deletion of Birc5 had no noticeable effect on proliferation but on apoptosis and the secretion of IFN-γ. The results revealed a significant increase in the percentage of Annexin V positive CD4⁺ T cells in the Birc5^-/- group, compared to the WT. Moreover, there was significant increase in early apoptotic alloreactive T cells in Birc5^-/- mice and this was partly mediated by caspase-3. Furthermore, treatment with YM155 inhibited acute heart allograft rejection in vivo and increased T-cell apoptosis in healthy human PBMCs in vitro. The results highlight a potential therapeutic target for the prevention and treatment of acute transplant rejection.

The Functional Impact of Alternative Splicing and Single Nucleotide Polymorphisms in Rheumatoid Arthritis

Advances in genomics and proteomics aid the identification of genes associated with various diseases. Genome-Wide Association Studies (GWAS) have identified multiple loci as risk alleles for susceptibility to Rheumatoid Arthritis (RA). A bisection of RA risk can be attributed to genetic factors. Over 100 associated genetic loci that encompass immune regulatory factors have been found to be linked with RA. Aberrant Single Nucleotide Polymorphisms (SNPs) and alternative splicing mechanisms in such loci induce RA. These aberrations are viewed as potential therapeutic targets due to their association with a multitude of diseases. This review presents a few imperious genes whose alterations can cause severe bone deformities culminating in RA.

Synoviocyte-targeted therapy synergizes with TNF inhibition in arthritis reversal

Fibroblast-like synoviocytes (FLS) are joint-lining cells that promote rheumatoid arthritis (RA) pathology. Current disease-modifying antirheumatic agents (DMARDs) operate through systemic immunosuppression. FLS-targeted approaches could potentially be combined with DMARDs to improve control of RA without increasing immunosuppression. Here, we assessed the potential of immunoglobulin-like domains 1 and 2 (Ig1&2), a decoy protein that activates the receptor tyrosine phosphatase sigma (PTPRS) on FLS, for RA therapy. We report that PTPRS expression is enriched in synovial lining RA FLS and that Ig1&2 reduces migration of RA but not osteoarthritis FLS. Administration of an Fc-fusion Ig1&2 attenuated arthritis in mice without affecting innate or adaptive immunity. Furthermore, PTPRS was down-regulated in FLS by tumor necrosis factor (TNF) via a phosphatidylinositol 3-kinase-mediated pathway, and TNF inhibition enhanced PTPRS expression in arthritic joints. Combination of ineffective doses of TNF inhibitor and Fc-Ig1&2 reversed arthritis in mice, providing an example of synergy between FLS-targeted and immunosuppressive DMARD therapies.

Protein prenylation restrains innate immunity by inhibiting Rac1 effector interactions

Rho family proteins are prenylated by geranylgeranyltransferase type I (GGTase-I), which normally target proteins to membranes for GTP-loading. However, conditional deletion of GGTase-I in mouse macrophages increases GTP-loading of Rho proteins, leading to enhanced inflammatory responses and severe rheumatoid arthritis. Here we show that heterozygous deletion of the Rho family gene Rac1, but not Rhoa and Cdc42, reverses inflammation and arthritis in GGTase-I-deficient mice. Non-prenylated Rac1 has a high affinity for the adaptor protein Ras GTPase-activating-like protein 1 (Iqgap1), which facilitates both GTP exchange and ubiquitination-mediated degradation of Rac1. Consistently, inactivating Iqgap1 normalizes Rac1 GTP-loading, and reduces inflammation and arthritis in GGTase-I-deficient mice, as well as prevents statins from increasing Rac1 GTP-loading and cytokine production in macrophages. We conclude that blocking prenylation stimulates Rac1 effector interactions and unleashes proinflammatory signaling. Our results thus suggest that prenylation normally restrains innate immune responses by preventing Rac1 effector interactions.

Macrophage specific deletion of GGTase-I, a prenylation enzyme, in mice induces inflammatory response and rheumatoid arthritis. Here the authors show that GGTase-I deficiency and the resulting reduction of RAC1 prenylation increase RAC1 interaction with the adaptor protein IQGAP1, leading to GTP-loading of RAC1 and enhanced proinflammatory cytokine production.

microRNA involvement in the regulation of survivin in peripheral blood mononuclear cells from rheumatoid arthritis patients

AIM

Impaired regulation of immune tolerance results in autoimmune diseases, such as rheumatoid arthritis (RA). Survivin is an anti-apoptotic protein and can induce cellular mitosis. In the current study, we assessed the transcript level of total survivin (survivin-TS) and its three major variants and evaluated the expression level of important micro RNAs (miRNAs) involved in survivin expression regulation in RA patients.

METHOD

Peripheral blood mononuclear cells (PBMCs) were isolated from 50 healthy controls and 50 RA-active patients. RNA extraction was performed and then single-strand complementary DNA was synthesized. Quantitative real-time polymerase chain reaction was used to assess the expression level of survivin-TS and its variants with effective miRNAs in PBMCs.

RESULTS

Overexpression of survivin-2B (fold change = 1.57, P = 0.005), survivn-ΔEx3 (fold change = 1.93, P = 0.009) and downregulation of survivin-WT (fold change = 0.64, P = 0.0002) were found in PBMCs of patients, while messenger RNA (mRNA) expression of survivin-TS had no significant difference between RA patients and controls. Expression levels of miR-335-5p, miR-485-5p, miR-16-5p, miR-150-5p, miR-34a-5p, and miR-203a-3p were significantly increased in PBMCs from patients compared with healthy controls. In a correlation study, dysregulation of these miRNAs were not correlated with mRNA expression level of survivin.

CONCLUSION

While survivin-TS was not differently expressed in RA patients, its variants had altered expression. Although miRNAs were aberrantly expressed in PBMCs from RA subjects, they did not regulate survivin-TS. miRNAs might be involved in RA pathogenesis, but not through controlling survivin.

Survivin induces defects in apoptosis in eosinophils in intestine with food allergy

Survivin is an anti-apoptosis protein that may be associated with the development of eosinophilia; the latter is associated with the pathogenesis of many immune disorders. Here we report that less apoptotic eosinophils (Eos) were induced in those isolated from mice suffering from food allergy (FA) than those from naive mice after treating with cisplatin in vitro. Exposure to cisplatin induced more Fas ligand (FasL) expression in Eos isolated from naive mice than in those of FA mouse. Survivin was detected in the intestinal tissue extracts in much higher amounts in the FA group than in the naive group. Immunohistochemistry showed that epithelial cells were the major source of survivin in the intestine. Exposure to IL-4 or IL-13 up-regulated the expression of survivin in intestinal epithelial cells. Survivin interfered with the expression of FasL in Eos. Inhibition of survivin attenuated the eosinophilia-related inflammation in the intestine. In conclusion, intestinal epithelial cell-produced survivin induced defects in apoptosis in Eos to contribute to eosinophilia in the intestine. Inhibition of survivin can suppress the eosinophilia-related intestinal inflammation. The data suggest that survivin may be a novel target for the treatment of FA.

Inflammation in the hippocampus affects IGF1 receptor signaling and contributes to neurological sequelae in rheumatoid arthritis

Aberrant insulin-like growth factor 1 receptor (IGF1R)/insulin receptor signaling in brain has recently been linked to neurodegeneration in diabetes mellitus and in Alzheimer’s disease. In this study, we demonstrate that functional disability and pain in patients with rheumatoid arthritis (RA) and in experimental RA are associated with hippocampal inflammation and inhibition of IGF1R/insulin receptor substrate 1 (IRS1) signal, reproducing an IGF1/insulin-resistant state. This restricts formation of new neurons in the hippocampus, reduces hippocampal volume, and predisposes RA patients to develop neurological symptoms. Improving IRS1 function through down-regulation of IGF1R disinhibits neurogenesis and can potentially ameliorate neurological symptoms. This opens perspectives for drugs that revert IGF1/insulin resistance as an essential complement to the antirheumatic and antiinflammatory arsenal.

Rheumatoid arthritis (RA) is an inflammatory joint disease with a neurological component including depression, cognitive deficits, and pain, which substantially affect patients’ quality of daily life. Insulin-like growth factor 1 receptor (IGF1R) signaling is one of the factors in RA pathogenesis as well as a known regulator of adult neurogenesis. The purpose of this study was to investigate the association between IGF1R signaling and the neurological symptoms in RA. In experimental RA, we demonstrated that arthritis induced enrichment of IBA1⁺ microglia in the hippocampus. This coincided with inhibitory phosphorylation of insulin receptor substrate 1 (IRS1) and up-regulation of IGF1R in the pyramidal cell layer of the cornus ammoni and in the dentate gyrus, reproducing the molecular features of the IGF1/insulin resistance. The aberrant IGF1R signaling was associated with reduced hippocampal neurogenesis, smaller hippocampus, and increased immobility of RA mice. Inhibition of IGF1R in experimental RA led to a reduction of IRS1 inhibition and partial improvement of neurogenesis. Evaluation of physical functioning and brain imaging in RA patients revealed that enhanced functional disability is linked with smaller hippocampus volume and aberrant IGF1R/IRS1 signaling. These results point to abnormal IGF1R signaling in the brain as a mediator of neurological sequelae in RA and provide support for the potentially reversible nature of hippocampal changes.

Survivin Measurement improves Clinical Prediction of Transition From Arthralgia to RA-Biomarkers to Improve Clinical Sensitivity of Transition From Arthralgia to RA

Background: Arthralgia often predates development of rheumatoid arthritis (RA). A set of joint symptoms commonly found in patients during their transition from arthralgia to RA, has been recently proposed.

Aim: To combine clinical and serological markers and to improve recognition of imminent rheumatoid arthritis (RA) among patients with arthralgia.

Methods: The total of 1,743 first-visit patients attending the rheumatology ward in Gothenburg for joint symptoms were identified during 12 consecutive months. Among those, 63 patients were classified as RA, 73 had undifferentiated arthritis and 180 had unexplained arthralgia. New RA cases, which prospectively developed during 48 months, comprised the preclinical (pre) RA group. The joint symptoms of the first-visit were analyzed aiming to distinguish patients with arthralgia and arthritis, and patients with pre-RA, who later developed the disease. The receiver operating characteristics curves were constructed. In the model, symptoms with the odds ratio >2.0 between the arthralgia and pre-RA were combined with information about RA-specific antibodies, C-reactive protein (CRP), and survivin in serum.

Results: The proposed set of clinical symptoms distinguished the arthralgia patients from RA and pre-RA. Presence of survivin in serum showed strong association with clinical joint symptoms in arthralgia. A combination of symptoms in several small joint areas, increasing number of joints with symptoms, and patient's experience of swelling in small hand joints at the first visit identified pre-RA cases with 93% specificity. Grouping those symptoms with information about survivin, RA-specific antibodies, and CRP (or gender) in the final algorithm achieved 91% specificity and 55.2% of positive prediction for transition from arthralgia to RA.

Conclusion: Clinical and serological parameters in combination aid recognition of imminent RA among arthralgia patients with appropriate sensitivity.

Collagen V oral administration decreases inflammation and remodeling of synovial membrane in experimental arthritis

Because collagen type V (Col V) can be exposed in tissue injury, we hypothesized that oral administration of this collagen species modulates the inflammation and remodeling of experimental synovitis, avoiding joint destruction, and that the modulation may differ according to the temporal administration. Arthritis (IA, n = 20) was induced in Lewis rats by intraarticular (ia) injection of 500 μg of methylated bovine serum albumin (mBSA) emulsified in complete Freund’s adjuvant (CFA) (10 μl) followed by an intraarticular booster of mBSA (50 μg) in saline (50 μl) administered at 7 and 14 days. The control group received saline (50 μl, ia). After the first intraarticular injection, ten IA animals were supplemented via gavage with Col V (500 μg/300 μl) daily for 30 days (IA/Suppl). The control group received saline (50 μL) and Col V supplement in the same way (Suppl). Col V oral administration in IA/Suppl led to 1) inhibited edema and severe inflammatory cell infiltration, 2) decreased collagen fiber content, 3) decreased collagen type I, 4) inhibited lymphocyte subpopulations and macrophages, 5) inhibited IL-1β, IL-10, IL-17 and TNF-α production and 6) increased expression of caspase-9 in the synovial tissue. In conclusion, Col V supplementation decreased synovial inflammation and the fibrotic response, possibly by increased the apoptosis of inflammatory cells.

Survivin in autoimmune diseases

Survivin is a protein functionally important for cell division, apoptosis, and possibly, for micro-RNA biogenesis. It is an established marker of malignant cell transformation. In non-malignant conditions, the unique properties of survivin make it indispensable for homeostasis of the immune system. Indeed, it is required for the innate and adaptive immune responses, controlling differentiation and maintenance of CD4⁺ and CD8⁺ memory T-cells, and in B cell maturation. Recently, survivin has emerged as an important player in the pathogenesis of autoimmune diseases. Under the conditions of unreserved inflammation, survivin enhances antigen presentation, maintains persistence of autoreactive cells, and supports production of autoantibodies. In this context, survivin takes its place as a diagnostic and prognostic marker in rheumatoid arthritis, psoriasis, systemic sclerosis and pulmonary arterial hypertension, neuropathology and multiple sclerosis, inflammatory bowel diseases and oral lichen planus. In this review, we summarise the knowledge about non-malignant properties of survivin and focus on its engagement in cellular and molecular pathology of autoimmune diseases. The review highlights utility of survivin measures for clinical applications. It provides rational for the survivin inhibiting strategies and presents results of recent reports on survivin inhibition in modern therapies of cancers and autoimmune diseases.

Rheumatoid Arthritis Fibroblast-like Synoviocyte Suppression Mediated by PTEN Involves Survivin Gene Silencing

Survivin is a proto-oncogene biomarker known for its anti-apoptotic and cell cycle regulating properties induced by the activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. In the context of non-cancer pathology, such as rheumatoid arthritis (RA), survivin has emerged as a feature associated with severe joint damage and poor treatment response. Phosphatase and tensin homolog (PTEN) is a phosphatase antagonizing all classes of PI3K. The interplay between survivin oncogenic mechanisms and proliferation suppression networks in RA has remained largely elusive. This study investigated the effect of PTEN on survivin gene expression in rheumatiod arthritis fibroblast-like synoviocyte (RA-FLS). We showed for the first time that the suppression of RA-FLS was mediated by PTEN involving survivin silencing. Considering that survivin suppressants are currently available in clinical trials and clinical use, their effects in RA-FLS support a probably RA therapy to clinical practice.

Smoking activates cytotoxic CD8+ T cells and causes survivin release in rheumatoid arthritis

CD8⁺ T cells have an emerging role in RA. Resent research indicates a causal relationship between the non-exhausted state of CD8⁺ T cells, defined by lost function of PD-1, and development of arthritis. We investigated how smoking contributes to the non-exhausted phenotype of CD8⁺ T cells and cause survivin release to serum. We compared serum survivin levels between smokers and non-smokers in 252 RA and 168 healthy subjects. Nicotine effects on CD8⁺ T cells were studied in peripheral blood of smoking women, bone marrow of nicotine treated mice and in sorted CD8 spleen cells in vitro using flow cytometry and quantitative PCR. Smoking increased the frequency of survivin release in serum of healthy women (OR 3.64, p = 0.025) and in RA patients (OR 1.98, p = 0.039). CD8⁺ T cells of smokers gained a non-exhausted PD-1 deficient phenotype. Expression of the cytotoxic marker CD107 correlated to survivin levels in serum. In the experimental setting, nicotine exposure led to an accumulation of non-exhausted PD-1^-IL-7R⁺ CD8⁺ T cells in the bone marrow that is abundant with survivin producing cells. The production of the cytolytic protein perforin in bone marrow correlated to serum survivin levels. In vitro stimulation of nicotinic receptors on murine CD8⁺ T cells induced repressive transcription factors T-bet and Blimp-1 in support of the non-exhausted phenotype. We conclude that nicotine contributes to autoimmunity by supporting the non-exhausted state of CD8⁺ T cells resulting in the release of survivin. This presents a new mechanism by which smoking may contribute to the pathogenesis of RA.

Survivin co-ordinates formation of follicular T-cells acting in synergy with Bcl-6

Follicular T helper (Tfh) cells are recognized by the expression of CXCR5 and the transcriptional regulator Bcl-6. Tfh cells control B cell maturation and antibody production, and if deregulated, may lead to autoimmunity. Here, we study the role of the proto-oncogene survivin in the formation of Tfh cells. We show that blood Tfh cells of patients with the autoimmune condition rheumatoid arthritis, have intracellular expression of survivin. Survivin was co-localized with Bcl-6 in the nuclei of CXCR5⁺CD4 lymphocytes and was immunoprecipitated with the Bcl-6 responsive element of the target genes. Inhibition of survivin in arthritic mice led to the reduction of CXCR5⁺ Tfh cells and to low production of autoantibodies. Exposure to survivin activated STAT3 and induced enrichment of PD-1⁺Bcl-6⁺ subset within Tfh cells. Collectively, our study demonstrates that survivin belongs to the Tfh cell phenotype and ensures their optimal function by regulating transcriptional activity of Bcl-6.

Serum survivin predicts responses to treatment in active rheumatoid arthritis: a post hoc analysis from the SWEFOT trial

BACKGROUND

The identification of biomarkers that predict optimal and individual choices of treatment for patients with rheumatoid arthritis gains increasing attention. The purpose of this study was to investigate if the proto-oncogene survivin might aid in treatment decisions in early rheumatoid arthritis.

METHODS

Serum survivin levels were measured in 302 patients who completed the Swedish pharmacotherapy (SWEFOT) trial at baseline, 3, 12, and 24 months. Survivin levels > 0.45 ng/mL were considered positive. Based on the survivin status, core set outcomes measuring disease activity, functional disability, as well as global health and pain were evaluated after methotrexate (MTX) monotherapy at 3 months, and at 12 and 24 months of follow-up. Treatment of non-responders was randomly intensified with either a combination of disease-modifying antirheumatic drugs (triple therapy: MTX, sulfasalazine, and hydroxychloroquine) or by adding antibodies against tumor necrosis factor (anti-TNF).

RESULTS

Antirheumatic treatment resulted in an overall decrease of serum survivin levels. Survivin-positive patients at baseline who initially responded to MTX had a higher risk of disease re-activation (OR 3.21 (95% CI 1.12-9.24), P = 0.032) and failed to improve in their functional disability (P = 0.018) if having continued on MTX monotherapy compared to survivin-negative patients. Ever-smokers who were survivin-positive were less likely to respond to MTX than those who were survivin-negative (OR 1.91 (1.01-3.62), P = 0.045). In survivin-positive patients, triple therapy led to better improvements in disease activity than did MTX + anti-TNF. At 24 months, survivin-positive patients randomized to anti-TNF had a higher risk of active disease than those randomized to triple therapy (OR 3.15 (1.09-9.10), P = 0.037).

DISCUSSION

We demonstrate for the first time that survivin is a valuable serologic marker that can distinguish drug-specific clinical responses in early rheumatoid arthritis through the pragmatic clinical setting of the care-based SWEFOT trial. Although treatment response cannot solely be attributable to survivin status, per protocol sensitivity analyses confirmed the superior effect of triple therapy on survivin-positive patients.

CONCLUSIONS

Survivin-positive patients have poor outcomes if treated with MTX monotherapy. A decrease of survivin levels during treatment is associated with better clinical responses. For survivin-positive patients who fail MTX, triple therapy is associated with better outcomes than anti-TNF therapy.

TRIAL REGISTRATION

WHO database at the Karolinska University Hospital: CT20080004 ; ClinicalTrials.gov: NCT00764725, registered 1 October 2008.

Suppressed diversity of survivin splicing in active rheumatoid arthritis

Introduction

Alternative splicing distinguishes normal and pathologic cells. High levels of oncoprotein survivin recognise patients with severe rheumatoid arthritis (RA). Here, we assess clinical relevance of alternative splicing of survivin in leukocytes of peripheral blood (PBMC) and bone marrow (BM) in RA patients.

Method

Transcription of survivin wild-type (survivin-WT), survivin-2B and survivin-ΔEx3 was measured in 67 randomly selected RA patients and in 23 patients before and after B cell depletion with rituximab. Analysis was done in relation to disease activity, anti-rheumatic treatment and serum levels of rheumatoid factor (RF) and survivin.

Results

Survivin-WT was the dominant splice variant equally expressed in T and B cells, while survivin-2B and survivin-ΔEx3 were higher in B cells. High disease activity (DAS28>5.1) was associated with an excess of survivin-WT and low ratios between survivin-2B/WT (p=0.035) and survivin-ΔEx3/WT in PBMC. Depletion of B cells by rituximab caused a decrease in survivin-WT (p=0.005) in PBMC, increasing the ratio between survivin-2B/WT (p=0.009) and survivin-ΔEx3/WT (p=0.001) in BM. This increase in survivin-2B/WT was associated with reduction in CD19+ BM cells (r=0.929, p=0.007), RF (IgM, r=0.857, p=0.024; IgA, r=0.739, p=0.021), and DAS28 (0.636, p=0.054). The increase in survivin-ΔEx3 in BM was associated with a reduction of CD19+ BM cells (r=0.714, p=0.058) and DAS28 (r=0.648, p=0.049), while survivin-ΔEx3/WT was associated with RF (IgG, r=0.882, p=0.016).

Conclusion

This study demonstrates that the suppressed diversity of survivin splicing in leukocytes may attribute to adverse self-recognition in RA. Depletion of autoantibody producing B cells improves the balance of survivin splicing.