Combination treatment with fingolimod and a pathogenic antigen prevents relapse of glucose-6-phosphate isomerase peptide-induced arthritis

The impact of fingolimod on Treg function in brain ischaemia

Fingolimod has generally shown neuroprotective effects in stroke models. Here, we tested the hypothesis that fingolimod modulates T-cell cytokine production towards a regulatory phenotype. Second, we investigated how fingolimod altered the Treg suppressive function and the sensitivity of effector T cells to regulation. Mice that had underwent the permanent electrocoagulation of the left middle cerebral artery received saline or fingolimod (0.5 mg/kg) daily for 10-days post-ischaemia. Fingolimod improved neurobehavioural recovery compared to saline control and increased Treg frequency in the periphery and brain. Tregs from fingolimod-treated animals had a higher expression of CCR8. Fingolimod increased the frequencies of CD4+ IL-10+ , CD4+ IFN-γ+ and CD4+ IL-10+ IFN-γ+ cells in spleen and blood, and CD4+ IL-17+ cells in the spleen, with only minor effects on CD8+ T-cell cytokine production. Treg from post-ischaemic mice had reduced suppressive function compared to Treg from non-ischaemic mice. Fingolimod treatment rescued this function against saline-treated but not fingolimod-treated CD4+ effector T cells. In conclusion, fingolimod seems to improve the suppressive function of Treg post-stroke while also increasing the resistance of CD4+ effector cells to this suppression. Fingolimod's capacity to increase both effector and regulatory functions may explain the lack of consistent improvement in functional recovery in experimental brain ischaemia.

Therapeutic strategy for rheumatoid arthritis by induction of myeloid-derived suppressor cells with high suppressive potential

Combination treatment using fingolimod (FTY720), an immunomodulator, and a pathogenic antigen prevents the progression of glucose-6-phosphate isomerase (GPI)_325-339-induced arthritis. In this study, we focused on myeloid-derived suppressor cells (MDSCs; CD11b⁺Gr-1⁺ cells) and investigated the effects of the combination treatment on these cells. DBA/1J mice with GPI_325-339-induced arthritis were treated using FTY720 and/or GPI_325-339 for five days. The expanded CD11b⁺Gr-1⁺ cell population and its inhibitory potential were examined. The percentage of CD369⁺CD11b⁺Gr-1⁺ cells effectively increased in the combination-treated mice. The inhibitory potential of CD369⁺CD11b⁺Gr-1⁺ cells was higher than that of cells not expressing CD369. Among bone marrow cells, the expression of CD369 in CD11b⁺Gr-1⁺ cells increased following stimulation with granulocyte-macrophage colony-stimulating factor, and the expression of CD11c increased accordingly. The increased CD11c expression indicated a decrease in the potential to suppress T cell proliferation based on the results of the suppression assay. The percentage of CD11c^-CD369⁺ cells in CD11b⁺Gr-1⁺ cells that were induced by the combination treatment also increased, and these cells tended to have a higher capacity to inhibit T cell proliferation. In conclusion, the combination treatment using FTY720 and the pathogenic antigen effectively induces MDSC, which demonstrates a high potential for suppressing T cell proliferation in the lymph nodes, thereby establishing an immune-tolerant state.

Molecular Pharmacology and Novel Potential Therapeutic Applications of Fingolimod

Fingolimod is a well-tolerated, highly effective disease-modifying therapy successfully utilized in the management of multiple sclerosis. The active metabolite, fingolimod-phosphate, acts on sphingosine-1-phosphate receptors (S1PRs) to bring about an array of pharmacological effects. While being initially recognized as a novel agent that can profoundly reduce T-cell numbers in circulation and the CNS, thereby suppressing inflammation and MS, there is now rapidly increasing knowledge on its previously unrecognized molecular and potential therapeutic effects in diverse pathological conditions. In addition to exerting inhibitory effects on sphingolipid pathway enzymes, fingolimod also inhibits histone deacetylases, transient receptor potential cation channel subfamily M member 7 (TRMP7), cytosolic phospholipase A2α (cPLA2α), reduces lysophosphatidic acid (LPA) plasma levels, and activates protein phosphatase 2A (PP2A). Furthermore, fingolimod induces apoptosis, autophagy, cell cycle arrest, epigenetic regulations, macrophages M1/M2 shift and enhances BDNF expression. According to recent evidence, fingolimod modulates a range of other molecular pathways deeply rooted in disease initiation or progression. Experimental reports have firmly associated the drug with potentially beneficial therapeutic effects in immunomodulatory diseases, CNS injuries, and diseases including Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and even cancer. Attractive pharmacological effects, relative safety, favorable pharmacokinetics, and positive experimental data have collectively led to its testing in clinical trials. Based on the recent reports, fingolimod may soon find its way as an adjunct therapy in various disparate pathological conditions. This review summarizes the up-to-date knowledge about molecular pharmacology and potential therapeutic uses of fingolimod.

Treatment approaches to patients with multiple sclerosis and coexisting autoimmune disorders

The past decades have yielded major therapeutic advances in many autoimmune conditions - such as multiple sclerosis (MS) - and thus ushered in a new era of more targeted and increasingly potent immunotherapies. Yet this growing arsenal of therapeutic immune interventions has also rendered therapy much more challenging for the attending physician, especially when treating patients with more than one autoimmune condition. Importantly, some therapeutic strategies are either approved for several autoimmune disorders or may be repurposed for other conditions, therefore opening new curative possibilities in related fields. In this article, we especially focus on frequent and therapeutically relevant concomitant autoimmune conditions faced by neurologists when treating patients with MS, namely psoriasis, rheumatoid arthritis and inflammatory bowel diseases. We provide an overview of the available disease-modifying therapies, highlight possible contraindications, show pathophysiological overlaps and finally present which therapeutics can be utilized as a combinatory treatment, in order to 'kill two birds with one stone'.

Characterization of an Expanded IL-10-Producing-Suppressive T Cell Population Associated with Immune Tolerance

An increase in the number of glucocorticoid-induced tumor necrosis factor receptor-family related gene/protein (GITR)⁺CD25^- (or fork-head box protein 3: Foxp3^-) CD4⁺ T cells, after treating a mouse model of arthritis with fingolimod (FTY720), and a pathogenic antigen may play a key role in the establishment of immune tolerance. In this study, we characterized a specific expanded T cell subset in this population. Mice with glucose-6-phosphate isomerase peptide (GPI_325-339)-induced arthritis were treated with FTY720 (1 mg/kg, per os) and GPI_325-339 (10 µg/mouse, intravenously) for five days, starting from the onset of symptoms. The expanded GITR⁺CD25^- (or Foxp3^-) CD4⁺ T cell population and its cytokine production were examined using flow cytometry. Furthermore, time-dependent changes in T-bet and/or early growth response gene 2 (Egr-2) expression in this T cell subset were examined. The density of T cell immunoreceptors with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)⁺CD39⁺ cell subset in the GITR⁺Foxp3^-CD4⁺ T cell population was significantly increased only in the combined treatment group, compared to that in the untreated and single-treatment groups. In the TIGIT⁺CD39⁺GITR⁺Foxp3^-CD4⁺ T cell population, T-bet⁺Egr-2⁺/T-bet⁺Egr-2^- cell ratio increased in the latter stage of the treatment. Furthermore, this T cell subset, which corresponded to a T helper 1 (Th1) response, produced high levels of both interleukin (IL)-10 and interferon (IFN)-γ. In conclusion, expanded TIGIT⁺CD39⁺GITR⁺Foxp3^-CD4⁺ T cells shifted from an effector Th1 to IL-10-producing-suppressor T cell phenotype, which may promote an immune-tolerant state.

Lactate Buildup at the Site of Chronic Inflammation Promotes Disease by Inducing CD4+ T Cell Metabolic Rewiring

Accumulation of lactate in the tissue microenvironment is a feature of both inflammatory disease and cancer. Here, we assess the response of immune cells to lactate in the context of chronic inflammation. We report that lactate accumulation in the inflamed tissue contributes to the upregulation of the lactate transporter SLC5A12 by human CD4+ T cells. SLC5A12-mediated lactate uptake into CD4+ T cells induces a reshaping of their effector phenotype, resulting in increased IL17 production via nuclear PKM2/STAT3 and enhanced fatty acid synthesis. It also leads to CD4+ T cell retention in the inflamed tissue as a consequence of reduced glycolysis and enhanced fatty acid synthesis. Furthermore, antibody-mediated blockade of SLC5A12 ameliorates the disease severity in a murine model of arthritis. Finally, we propose that lactate/SLC5A12-induced metabolic reprogramming is a distinctive feature of lymphoid synovitis in rheumatoid arthritis patients and a potential therapeutic target in chronic inflammatory disorders.

Immunophenotype and Transcriptome Profile of Patients With Multiple Sclerosis Treated With Fingolimod: Setting Up a Model for Prediction of Response in a 2-Year Translational Study

BACKGROUND

Fingolimod is a functional sphingosine-1-phosphate antagonist approved for the treatment of multiple sclerosis (MS). Fingolimod affects lymphocyte subpopulations and regulates gene expression in the lymphocyte transcriptome. Translational studies are necessary to identify cellular and molecular biomarkers that might be used to predict the clinical response to the drug. In MS patients, we aimed to clarify the differential effects of fingolimod on T, B, and natural killer (NK) cell subsets and to identify differentially expressed genes in responders and non-responders (NRs) to treatment.

MATERIALS AND METHODS

Samples were obtained from relapsing-remitting multiple sclerosis patients before and 6 months after starting fingolimod. Forty-eight lymphocyte subpopulations were measured by flow cytometry based on surface and intracellular marker analysis. Transcriptome sequencing by next-generation technologies was used to define the gene expression profiling in lymphocytes at the same time points. NEDA-3 (no evidence of disease activity) and NEDA-4 scores were measured for all patients at 1 and 2 years after beginning fingolimod treatment to investigate an association with cellular and molecular characteristics.

RESULTS

Fingolimod affects practically all lymphocyte subpopulations and exerts a strong effect on genetic transcription switching toward an anti-inflammatory and antioxidant response. Fingolimod induces a differential effect in lymphocyte subpopulations after 6 months of treatment in responder and NR patients. Patients who achieved a good response to the drug compared to NR patients exhibited higher percentages of NK bright cells and plasmablasts, higher levels of FOXP3, glucose phosphate isomerase, lower levels of FCRL1, and lower Expanded Disability Status Scale at baseline. The combination of these possible markers enabled us to build a probabilistic linear model to predict the clinical response to fingolimod.

CONCLUSION

MS patients responsive to fingolimod exhibit a recognizable distribution of lymphocyte subpopulations and a different pretreatment gene expression signature that might be useful as a biomarker.

Transcription Factors Downstream of IL-4 and TGF-β Signals: Analysis by Quantitative PCR, Western Blot, and Flow Cytometry

IL-9-producing Th9 cell is a novel Th cell subset involved in type II allergic inflammations such as asthma. Th9 cells can be induced from naïve Th cells in the presence of IL-4 and TGF-β. It is also well established that downstream signals of IL-4 and TGF-β, including STAT6, IRF4, Smad, and PU.1, directly mediate IL-9 production in Th9 cells. In this chapter we describe the methods of flow cytometry, qPCR and western blot analysis to determine the expression or activation of these transcription factors downstream of IL-4 and TGF-β.