Interleukin-7 is required for CD4(+) T cell activation and autoimmune neuroinflammation

SIMBA: single-cell embedding along with features

Most current single-cell analysis pipelines are limited to cell embeddings and rely heavily on clustering, while lacking the ability to explicitly model interactions between different feature types. Furthermore, these methods are tailored to specific tasks, as distinct single-cell problems are formulated differently. To address these shortcomings, here we present SIMBA, a graph embedding method that jointly embeds single cells and their defining features, such as genes, chromatin-accessible regions and DNA sequences, into a common latent space. By leveraging the co-embedding of cells and features, SIMBA allows for the study of cellular heterogeneity, clustering-free marker discovery, gene regulation inference, batch effect removal and omics data integration. We show that SIMBA provides a single framework that allows diverse single-cell problems to be formulated in a unified way and thus simplifies the development of new analyses and extension to new single-cell modalities. SIMBA is implemented as a comprehensive Python library ( https://simba-bio.readthedocs.io ).

Rare SH2B3 coding variants in lupus patients impair B cell tolerance and predispose to autoimmunity

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a clear genetic component. While most SLE patients carry rare gene variants in lupus risk genes, little is known about their contribution to disease pathogenesis. Amongst them, SH2B3-a negative regulator of cytokine and growth factor receptor signaling-harbors rare coding variants in over 5% of SLE patients. Here, we show that unlike the variant found exclusively in healthy controls, SH2B3 rare variants found in lupus patients are predominantly hypomorphic alleles, failing to suppress IFNGR signaling via JAK2-STAT1. The generation of two mouse lines carrying patients' variants revealed that SH2B3 is important in limiting the number of immature and transitional B cells. Furthermore, hypomorphic SH2B3 was shown to impair the negative selection of immature/transitional self-reactive B cells and accelerate autoimmunity in sensitized mice, at least in part due to increased IL-4R signaling and BAFF-R expression. This work identifies a previously unappreciated role for SH2B3 in human B cell tolerance and lupus risk.

JAK-STAT signaling in inflammation and stress-related diseases: implications for therapeutic interventions

The Janus kinase-signal transducer and transcription activator pathway (JAK-STAT) serves as a cornerstone in cellular signaling, regulating physiological and pathological processes such as inflammation and stress. Dysregulation in this pathway can lead to severe immunodeficiencies and malignancies, and its role extends to neurotransduction and pro-inflammatory signaling mechanisms. Although JAK inhibitors (Jakinibs) have successfully treated immunological and inflammatory disorders, their application has generally been limited to diseases with similar pathogenic features. Despite the modest expression of JAK-STAT in the CNS, it is crucial for functions in the cortex, hippocampus, and cerebellum, making it relevant in conditions like Parkinson's disease and other neuroinflammatory disorders. Furthermore, the influence of the pathway on serotonin receptors and phospholipase C has implications for stress and mood disorders. This review expands the understanding of JAK-STAT, moving beyond traditional immunological contexts to explore its role in stress-related disorders and CNS function. Recent findings, such as the effectiveness of Jakinibs in chronic conditions such as rheumatoid arthritis, expand their therapeutic applicability. Advances in isoform-specific inhibitors, including filgotinib and upadacitinib, promise greater specificity with fewer off-target effects. Combination therapies, involving Jakinibs and monoclonal antibodies, aiming to enhance therapeutic specificity and efficacy also give great hope. Overall, this review bridges the gap between basic science and clinical application, elucidating the complex influence of the JAK-STAT pathway on human health and guiding future interventions.

The Peripheral Immune Landscape in a Patient with Myocarditis after the Administration of BNT162b2 mRNA Vaccine

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed a serious threat to global public health. A novel vaccine made from messenger RNA (mRNA) has been developed and approved for use at an unprecedented pace. However, an increased risk of myocarditis has been reported after BNT162b2 mRNA vaccination due to unknown causes. In this study, we used single-cell RNA sequencing and single-cell T cell receptor sequencing analyses of peripheral blood mononuclear cells (PBMCs) to describe, for the first time, changes in the peripheral immune landscape of a patient who underwent myocarditis after BNT162b2 vaccination. The greatest changes were observed in the transcriptomic profile of monocytes in terms of the number of differentially expressed genes. When compared to the transcriptome of PBMCs from vaccinated individuals without complications, increased expression levels of IL7R were detected in multiple cell clusters. Overall, results from this study can help advance research into the pathogenesis of BNT162b2-induced myocarditis.

Antisense modulation of IL7R splicing to control sIL7R expression in human CD4+ T cells

The interleukin 7 receptor (IL7R) is strongly associated with increased risk to develop multiple sclerosis (MS), an autoimmune disease of the central nervous system, and this association is likely driven by up-regulation of the soluble isoform of IL7R (sIL7R). Expression of sIL7R is determined by exclusion of the alternative exon 6 from IL7R transcripts, and our previous work revealed that the MS risk allele of the SNP rs6897932 within this exon enhances the expression of sIL7R by promoting exclusion of exon 6. sIL7R potentiates the activity of IL7, leading to enhanced expansion of T cells and increased disability in the experimental autoimmune encephalomyelitis (EAE) murine model of MS. This role in modulating T cell-driven immunity positions sIL7R as an attractive therapeutic target whose expression could be reduced for treatment of MS or increased for treatment of cancers. In this study, we identified novel antisense oligonucleotides (ASOs) that effectively control the inclusion (anti-sIL7R ASOs) or exclusion (pro-sIL7R ASOs) of this exon in a dose-dependent fashion. These ASOs provided excellent control of exon 6 splicing and sIL7R secretion in human primary CD4⁺ T cells. Supporting their potential for therapeutic targeting, we showed that lead anti-sIL7R ASOs correct the enhanced exon 6 exclusion imposed by the MS risk allele of rs6897932, whereas lead pro-sIL7R ASOs phenocopy it. The data presented here form the foundation for future preclinical studies that will test the therapeutic potential of these ASOs in MS and immuno-oncology.

Change of Serum Biomarkers to Post-Thrombolytic Symptomatic Intracranial Hemorrhage in Stroke

Background

Symptomatic intracranial hemorrhage (sICH) is a terrible complication after intravenous alteplase in stroke, and numerous biomarkers have been investigated. However, the change of biomarkers to sICH has not been well determined.

Aim

To investigate the association between the change of biomarkers and sICH.

Methods

This is a prospective cohort study, and patients with sICH within 24 h after thrombolysis were enrolled, while patients without sICH were matched by propensity score matching with a ratio of 1:1. The blood samples were collected before and 24 h after intravenous thrombolysis (IVT), and preset 49 serum biomarkers were measured by microarray analysis. Protein function enrichment analyses were performed to detect the association between the change of biomarkers and sICH.

Results

Of consecutive 358 patients, 7 patients with sICH in 24 h were assigned to the sICH group, while 7 matched patients without any ICH were assigned to the non-sICH group. A total of 9 biomarkers were found to significantly change before vs. after thrombolysis between groups, including increased biomarkers, such as brain-derived neurotrophic factor, C-C motif chemokine ligand (CCL)-24, interleukin (IL)-6, IL-10, IL-18, and vascular endothelial growth factor, and decreased biomarkers, such as CCL-11, intercellular adhesion molecule-1, and IL-7.

Conclusions

This is the first study to identify changes in serum biomarkers in patients with sICH after IVT, and found that 6 neuroinflammatory and 3 neuroprotective biomarkers may be associated with brain injury following post-thrombolytic sICH.

Clinical Trial Registration

https://www.clinicaltrials.gov, identifier: NCT02854592.

Sex-Specific Microglial Activation and SARS-CoV-2 Receptor Expression Induced by Chronic Unpredictable Stress

The coronavirus disease 2019 (COVID-19) pandemic has generated a lot of stress and anxiety among not only infected patients but also the general population across the globe, which disturbs cerebral immune homeostasis and potentially exacerbates the SARS-CoV-2 virus-induced neuroinflammation, especially among people susceptible to neuropsychiatric disorders. Here, we used a chronic unpredictable mild stress (CUMS) mouse model to study its effects on glia-mediated neuroinflammation and expression of SARS-CoV2 viral receptors. We observed that female mice showed depressive-like behavior after CUMS, whereas male mice showed enhanced anxiety and social withdrawal. Interestingly, CUMS led to increased amounts of total and MHCII⁺ microglia in the hippocampi of female mice but not male mice. mRNA levels of SARS-CoV-2 viral receptors angiotensin-converting enzyme 2 (Ace2) and basigin (Bsg) were also upregulated in the prefrontal cortices of stressed female mice but not male mice. Similarly, sex-specific changes in SARS-CoV-2 viral receptors FURIN and neuropilin-1 (NRP1) were also observed in monocytes of human caregivers enduring chronic stress. Our findings provided evidence on detrimental effects of chronic stress on the brain and behavior and implied potential sex-dependent susceptibility to SARS-CoV-2 infection after chronic stress.

Immunomodulation and Regenerative Capacity of MSCs for Long-COVID

The rapid mutation of the SARS-CoV-2 virus is now a major concern with no effective drugs and treatments. The severity of the disease is linked to the induction of a cytokine storm that promotes extensive inflammation in the lung, leading to many acute lung injuries, pulmonary edema, and eventually death. Mesenchymal stem cells (MSCs) might prove to be a treatment option as they have immunomodulation and regenerative properties. Clinical trials utilizing MSCs in treating acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) have provided a basis in treating post-COVID-19 patients. In this review, we discussed the effects of MSCs as an immunomodulator to reduce the severity and death in patients with COVID-19, including the usage of MSCs as an alternative regenerative therapy in post-COVID-19 patients. This review also includes the current clinical trials in utilizing MSCs and their potential future utilization for long-COVID treatments.

Identification of new IL-7Rα small-molecule agonists: a multi-computational approach

Interleukin 7 (IL-7) is an essential cytokine that acts as a potent growth factor of T-cells and supports the growth of B-cell precursors. IL-7 binds to a heterodimeric receptor consisting of an IL-7 receptor alpha (IL-7Rα) and the common gamma chain receptor (γc) which is shared with IL-2, IL-4, IL-9, IL-15 and IL-21. The discovery of small-molecule agonists of cytokines would be of great pharmaceutical interest with the increasing scientific rationale. In this study, a series of molecular modelling methods, including field-based pharmacophore virtual screening, protein-protein docking and molecular dynamics simulations, led to the identification of two compounds (i.e. 1 and 2) of different classes that exhibit enhanced agonistic effects by activating the IL-7 signalling cascade. One of these compounds was selected as a hit and represents the first small-molecule agonist of IL-7Rα with single-digit micromolar activity. Moreover, the prediction model of the active compound to the IL-7Rα/γc interaction complex provides insight into the binding of a small-molecule agonist to its receptor.

Functional antibodies and innate immune responses to WRSS1, a live oral Shigella sonnei vaccine candidate in Bangladeshi adults and children

Background

We demonstrated in a randomized placebo-controlled trial that WRSS1, a live oral Shigella sonnei vaccine candidate, is safe in Bangladeshi adults and children, and elicits antigen-specific antibodies. Here, we describe functional antibody and innate immune responses to WRSS1.

Methods

Adults (18–39 years) and children (5–9 years) received 3 doses of 3 × 10⁵ or 3 × 10⁶ colony forming units (CFU) of WRSS1 or placebo, 4 weeks apart; children additionally received 3 × 10⁴ CFU. Blood and stool were collected at baseline and 7 days after each dose. Functional antibodies were measured using serum bactericidal antibody (SBA) assay. Cytokine/chemokine concentrations were measured in lymphocyte cultures. Host defense peptides LL-37, HBD-1, and HD-5 were analyzed in plasma and stool.

Results

Children showed increased SBA titers over baseline after the third dose of 3 × 10⁶ CFU (P = .048). Significant increases of Th-17 and proinflammatory cytokines (TNF-α, G-CSF, MIP-1β), and reduction of anti-inflammatory and Th2 cytokines (IL-10, IL-13, GM-CSF) were observed in children. Plasma HBD-1 and LL-37 decreased in children after vaccination but were increased/unchanged in adults.

Conclusions

Functional antibodies and Th1/Th17 cytokine responses in children may serve as important indicators of immunogenicity and protective potential of WRSS1.

Clinical Trials Registration: NCT01813071.

MiR-126, IL-7, CXCR1/2 receptors, inflammation and circulating endothelial progenitor cells: The study on targets for treatment pathways in a model of subclinical cardiovascular disease (type 1 diabetes mellitus)

Background

Type 1 diabetes (T1DM) is associated with premature cardiovascular disease (CVD) and a pro-inflammatory state whilst the proangiogenic miR-126-3p/-5p may play a role in CVD. Animal studies established miR-126 to be pro-angiogenic. We hypothesised miR-126-3p/-5p are reduced in T1DM whilst pro-inflammatory cytokines are increased.

Methods

29 well controlled, T1DM patients without CVD and 20 healthy controls (HCs) were studied. MiR-126-3p/-5p were assayed in plasma and peripheral blood mononuclear cells (PBMCs) whilst Chemokine C-X-C Receptor 1/2 (CXCR1/2) mRNA in PBMCs by real-time quantitative PCR. Cytokines were assayed by the Mesoscale Discovery. Ingenuity Pathway Analysis (IPA) was used to predict target genes, cellular functions and pathological states regulated by miR-126-3p/-5p. IPA generated both direct and indirect causations between different targets and analysed whether these effects would be inhibitory or stimulatory based on the published evidence.

Results

T1DM patients had a relatively good diabetic control (HbA1c = 7.4 ± 0.7% or 57.3 ± 7.6 mmol/mol). Homeostatic cytokine IL-7, pro-inflammatory cytokines IL-8 and TNF-α, and vascular endothelial growth factor-C (VEGF-C) were increased in T1DM, versus HCs; p = 0.008, p = 0.003, p = 0.041 and p = 0.013 respectively. MiR-126-5p was significantly upregulated in PBMCs in T1DM versus HCs; p = 0.01, but not in plasma. MiR-126-3p was unchanged. CXCR1/2 were elevated in T1DM versus HCs; p = 0.009 and p < 0.001 respectively. MiR-126-5p was positively correlated with CXCR1/2, and with HbA1c whilst negatively correlated with circulating endothelial progenitor cells (CD34⁺CD133⁺CD45^dim) and fibronectin adhesion assay in a combined group of T1DM patients and HCs; p = 0.028 p = 0.049 p = 0.035 p = 0.047 and p = 0.004 respectively. IPA predicted miR-126-5p to be anti-inflammatory through the inhibition of chemokine C–C motif ligand 27, chymotrypsin-like elastase 2A and IL-7, whilst miR-126-3p had no direct anti-inflammatory effect. Simultaneously IPA predicted IL-7 as the most upstream cytokine target.

Conclusions

T1DM without apparent CVD or diabetic complications is an inflammatory state characterised not only by raised pro-inflammatory cytokines but also by increased receptor CXCR1/2 and miR-126-5p. MiR-126-5p upregulation may represent a compensatory response. Pro-miR-126-5p therapies or anti-IL-7 therapies may be a new option to reduce both inflammation and CVD risk in T1DM. Further research is required in a large prospective study in patients with T1DM.

Neurological risks and benefits of cytokine-based treatments in coronavirus disease 2019: from preclinical to clinical evidence

Immunodeficiency and hyperinflammation are responsible for the most frequent and life-threatening forms of coronavirus disease 2019 (COVID-19). Therefore, cytokine-based treatments targeting immuno-inflammatory mechanisms are currently undergoing clinical scrutiny in COVID-19-affected patients. In addition, COVID-19 patients also exhibit a wide range of neurological manifestations (neuro-COVID), which may also benefit from cytokine-based treatments. In fact, such drugs have shown some clinical efficacy also in neuroinflammatory diseases. On the other hand, anti-cytokine drugs are endowed with significant neurological risks, mainly attributable to their immunodepressant effects. Therefore, the aim of the present manuscript is to briefly describe the role of specific cytokines in neuroinflammation, to summarize the efficacy in preclinical models of neuroinflammatory diseases of drugs targeting these cytokines and to review the clinical data regarding the neurological effects of these drugs currently being investigated against COVID-19, in order to raise awareness about their potentially beneficial and/or detrimental neurological consequences.

Model-Based Characterization of the Pharmacokinetics, Target Engagement Biomarkers, and Immunomodulatory Activity of PF-06342674, a Humanized mAb Against IL-7 Receptor-α, in Adults with Type 1 Diabetes

IL-7 receptor-α (IL-7Rα) blockade has been shown to reverse autoimmune diabetes in the non-obese diabetic mouse by promoting inhibition of effector T cells and consequently altering the balance of regulatory T (T_reg) and effector memory (T_EM) cells. PF-06342674 is a humanized monoclonal antibody that binds to and inhibits the function of IL-7Rα. In the current phase 1b study, subjects with type 1 diabetes (T1D) received subcutaneous doses of either placebo or PF-06342674 (1, 3, 8 mg/kg/q2w or 6 mg/kg/q1w) for 10 weeks and were followed up to 18 weeks. Nonlinear mixed effects models were developed to characterize the pharmacokinetics (PK), target engagement biomarkers, and immunomodulatory activity. PF-06342674 was estimated to have 20-fold more potent inhibitory effect on T_EM cells relative to T_reg cells resulting in a non-monotonic dose-response relationship for the T_reg:T_EM ratio, reaching maximum at ~ 3 mg/kg/q2w dose. Target-mediated elimination led to nonlinear PK with accelerated clearance at lower doses due to high affinity binding and rapid clearance of the drug-target complex. Doses ≥ 3 mg/kg q2w result in sustained PF-06342674 concentrations higher than the concentration of cellular IL-7 receptor and, in turn, maintain near maximal receptor occupancy over the dosing interval. The results provide important insight into the mechanism of IL-7Rα blockade and immunomodulatory activity of PF-06342674 and establish a rational framework for dose selection for subsequent clinical trials of PF-06342674. Furthermore, this analysis serves as an example of mechanistic modeling to support dose selection of a drug candidate in the early phases of development.

Predicting bacterial infection outcomes using single cell RNA-sequencing analysis of human immune cells

Complex interactions between different host immune cell types can determine the outcome of pathogen infections. Advances in single cell RNA-sequencing (scRNA-seq) allow probing of these immune interactions, such as cell-type compositions, which are then interpreted by deconvolution algorithms using bulk RNA-seq measurements. However, not all aspects of immune surveillance are represented by current algorithms. Here, using scRNA-seq of human peripheral blood cells infected with Salmonella, we develop a deconvolution algorithm for inferring cell-type specific infection responses from bulk measurements. We apply our dynamic deconvolution algorithm to a cohort of healthy individuals challenged ex vivo with Salmonella, and to three cohorts of tuberculosis patients during different stages of disease. We reveal cell-type specific immune responses associated not only with ex vivo infection phenotype but also with clinical disease stage. We propose that our approach provides a predictive power to identify risk for disease, and human infection outcomes.

Complex interactions between different host immune cell types can determine the outcome of pathogen infections. Here, Avraham and colleagues present a deconvolution algorithm that uses single-cell RNA and bulk RNA sequencing measurements of pathogen-infected cells to predict disease risk outcomes.

The Prognostic Value of Serum Cytokines in Patients with Acute Ischemic Stroke

The inflammatory response is an unavoidable process and contributes to the destruction of cerebral tissue during the acute ischemic stroke (AIS) phase and has not been addressed fully to date. Insightful understanding of correlation of inflammatory mediators and stroke outcome may provide new biomarkers or therapeutic approaches for ischemic stroke. Here, we prospectively recruited 180 first-ever AIS patients within 72 hrs after stroke onset. We used the National Institutes of Health Stroke Scale (NIHSS) to quantify stroke severity and modified Rankin scale (mRS) to assess the 3-month outcome for AIS patients. Initially, we screened 35 cytokines, chemokines, and growth factors in sera from 75 AIS patients and control subjects. Cytokines that were of interest were further investigated in the 180 AIS patients and 14 heathy controls. We found that IL-1RA, IL-1β, IL-4, IL-5, IL-6, IL-7, IL-9, IL-10, IL-13, IL-15, EGF, G-CSF, Flt-3L, GM-CSF and Fractalkine levels were significantly decreased in severe stroke patients. In particular, IL-1β, IL-4, IL-5, IL-7, IL-9, IL-10, IL-15, G-CSF and GM-CSF were significantly reduced in AIS patients with poor outcome, compared to those with good prognosis. IL-6 was notably higher in the poor outcome group. Only IL-9 level decreased in the large infarct volume group. After adjusting for confounders, we found that IL-5 was an independent protective factor for prognosis in AIS patients with an adjusted OR of 0.042 (P = 0.007), whereas IL-6 was an independent risk predictor for AIS patients with an adjusted OR of 1.293 (P = 0.003). Our study suggests the levels of serum cytokines are related to stroke severity, short-term prognosis and cerebral infarct volume in AIS patients.

Transcriptome analysis of normal-appearing white matter reveals cortisol- and disease-associated gene expression profiles in multiple sclerosis

Inter-individual differences in cortisol production by the hypothalamus–pituitary–adrenal (HPA) axis are thought to contribute to clinical and pathological heterogeneity of multiple sclerosis (MS). At the same time, accumulating evidence indicates that MS pathogenesis may originate in the normal-appearing white matter (NAWM). Therefore, we performed a genome-wide transcriptional analysis, by Agilent microarray, of post-mortem NAWM of 9 control subjects and 18 MS patients to investigate to what extent gene expression reflects disease heterogeneity and HPA-axis activity. Activity of the HPA axis was determined by cortisol levels in cerebrospinal fluid and by numbers of corticotropin-releasing neurons in the hypothalamus, while duration of MS and time to EDSS6 served as indicator of disease severity. Applying weighted gene co-expression network analysis led to the identification of a range of gene modules with highly similar co-expression patterns that strongly correlated with various indicators of HPA-axis activity and/or severity of MS. Interestingly, molecular profiles associated with relatively mild MS and high HPA-axis activity were characterized by increased expression of genes that actively regulate inflammation and by molecules involved in myelination, anti-oxidative mechanism, and neuroprotection. Additionally, group-wise comparisons of gene expression in white matter from control subjects and NAWM from (subpopulations of) MS patients uncovered disease-associated gene expression as well as strongly up- or downregulated genes in patients with relatively benign MS and/or high HPA-axis activity, with many differentially expressed genes being previously undescribed in the context of MS. Overall, the data suggest that HPA-axis activity strongly impacts on molecular mechanisms in NAWM of MS patients, but partly also independently of disease severity.

A fully human anti-IL-7Rα antibody promotes antitumor activity against T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological cancer for which treatment options often result in incomplete therapeutic efficacy and long-term side-effects. Interleukin 7 (IL-7) and its receptor IL-7Rα promote T-ALL development and mutational activation of IL-7Rα associates with very high risk in relapsed disease. Using combinatorial phage-display libraries and antibody reformatting, we generated a fully human IgG1 monoclonal antibody (named B12) against both wild-type and mutant human IL-7Rα, predicted to form a stable complex with IL-7Rα at a different site from IL-7. B12 impairs IL-7/IL-7R-mediated signaling, sensitizes T-ALL cells to treatment with dexamethasone and can induce cell death per se. The antibody also promotes antibody-dependent natural killer-mediated leukemia cytotoxicity in vitro and delays T-cell leukemia development in vivo, reducing tumor burden and promoting mouse survival. B12 is rapidly internalized and traffics to the lysosome, rendering it an attractive vehicle for targeted intracellular delivery of cytotoxic cargo. Consequently, we engineered a B12–MMAE antibody–drug conjugate and provide proof-of-concept evidence that it has increased leukemia cell killing abilities as compared with the naked antibody. Our studies serve as a stepping stone for the development of novel targeted therapies in T-ALL and other diseases where IL-7Rα has a pathological role.

IL-7 receptor blockade blunts antigen-specific memory T cell responses and chronic inflammation in primates

Targeting the expansion of pathogenic memory immune cells is a promising therapeutic strategy to prevent chronic autoimmune attacks. Here we investigate the therapeutic efficacy and mechanism of new anti-human IL-7Rα monoclonal antibodies (mAb) in non-human primates and show that, depending on the target epitope, a single injection of antagonistic anti-IL-7Rα mAbs induces a long-term control of skin inflammation despite repeated antigen challenges in presensitized monkeys. No modification in T cell numbers, phenotype, function or metabolism is observed in the peripheral blood or in response to polyclonal stimulation ex vivo. However, long-term in vivo hyporesponsiveness is associated with a significant decrease in the frequency of antigen-specific T cells producing IFN-γ upon antigen restimulation ex vivo. These findings indicate that chronic antigen-specific memory T cell responses can be controlled by anti-IL-7Rα mAbs, promoting and maintaining remission in T-cell mediated chronic inflammatory diseases.

Anti-IL-7 receptor-α treatment ameliorates newly established Sjögren's-like exocrinopathy in non-obese diabetic mice

The levels of interleukin (IL)-7 and its receptor are elevated in the salivary glands of patients with Sjögren's syndrome (SS). Our previous study indicates that IL-7 plays a critical pathogenic role in the development and onset of SS in a mouse model of this disease. The present study aims at determining whether IL-7 also plays a role in sustaining SS pathologies after the disease onset, by using the non-obese diabetic (NOD) model. Intraperitoneal administration of a blocking antibody against the IL-7 receptor α chain (IL-7Rα) to female NOD mice aged 10 weeks, which exhibited newly onset clinical SS, for the duration of 3 weeks significantly ameliorated characteristic SS pathologies including hyposalivation and leukocyte infiltration of the submandibular glands (SMGs). These changes were accompanied by a decrease in IFN-γ-producing CD4 T- and CD8 T cells, B cells, and lymphocyte chemoattractants CXCL9, -10, -11 and -13 in the SMGs. Anti-IL-7Rα treatment markedly diminished the amount of TNF-α in the SMGs and increased the level of claudin-1 and aquaporin 5, two molecules critical for normal salivary secretion. Furthermore, neutralization of IFN-γ and TNF-α, individually or in combination, considerably improved salivary secretion, reduced leukocyte infiltration and down-regulated CXCL9 and -13 expression in the SMGs. Collectively, the results indicate that endogenous IL-7R signals promote Th1 and Tc1 responses and IFN-γ- and TNF-α production to sustain the persistence of SS-like sialadenitis in NOD mice. These findings suggest that IL-7 and Th1 cytokines could serve as promising therapeutic targets for this prevalent autoimmune disease.

Down-regulation of interleukin 7 receptor (IL-7R) contributes to central nervous system demyelination

Interleukin 7 receptor (IL-7R) has been associated with the pathogenesis of multiple sclerosis (MS), though the mechanisms are not clear. Because myelin expression is highly conserved between zebrafish and mammals, zebrafish have become an ideal model for studying demyelination. We used a transgenic (Tg; mbp:nfsB-egfp) zebrafish line in which oligodendrocytes expressed green fluorescent protein (GFP) from the larval stage to adulthood. Exposing adult transgenic zebrafish to metronidazole induced demyelination that resembled the morphological changes associated with the early stages of MS. The metronidazole-induced demyelination was confirmed by magnetic resonance imaging (MRI) for the first time. Microarray analysis revealed down-regulation of IL-7R during demyelination. Targeted knockdown of IL-7R demonstrated that IL-7R is essential for myelination in embryonic and larval zebrafish. Moreover, IL-7R down-regulation induced signaling via the JAK/STAT pathway leading to apoptosis in oligodendrocytes. These findings contribute to our understanding of the role of IL-7R in demyelination, and provide a rationale for the development of IL-7R-based therapies for MS and other demyelinating diseases.

Human Epistatic Interaction Controls IL7R Splicing and Increases Multiple Sclerosis Risk

Multiple sclerosis (MS) is an autoimmune disorder where T cells attack neurons in the central nervous system (CNS) leading to demyelination and neurological deficits. A driver of increased MS risk is the soluble form of the interleukin-7 receptor alpha chain gene (sIL7R) produced by alternative splicing of IL7R exon 6. Here, we identified the RNA helicase DDX39B as a potent activator of this exon and consequently a repressor of sIL7R, and we found strong genetic association of DDX39B with MS risk. Indeed, we showed that a genetic variant in the 5' UTR of DDX39B reduces translation of DDX39B mRNAs and increases MS risk. Importantly, this DDX39B variant showed strong genetic and functional epistasis with allelic variants in IL7R exon 6. This study establishes the occurrence of biological epistasis in humans and provides mechanistic insight into the regulation of IL7R exon 6 splicing and its impact on MS risk.

Broad induction of immunoregulatory mechanisms after a short course of anti-IL-7Rα antibodies in NOD mice

BACKGROUND

Type 1 diabetes is an autoimmune disease caused by T cell-mediated destruction of the insulin-producing β-cells in the pancreas. Therefore, approaches that effectively halt the pathogenic T cell response are predicted to have preventive or therapeutic benefit for type 1 diabetes patients. We previously demonstrated that long-term blocking of IL-7 signaling, which is critical for the survival and function of T cells, prevented and reversed type 1 diabetes in non-obese diabetic mice. However, such persistent inhibition of T cell responses raises concerns about causing immunodeficiency. Here, we asked whether a reduced duration of the treatment with anti-IL-7Rα antibodies retained efficacy in preventing diabetes. Moreover, we sought to identify immunoregulatory mechanisms induced by anti-IL-7Rα administration.

RESULTS

Anti-IL-7Rα antibodies were administered to prediabetic NOD mice for 3 weeks and blood samples were taken at the end of treatment and 2 weeks later to analyze changes in T cell phenotypes in response to IL-7Rα blockade. We found that the co-inhibitory receptors LAG-3, Tim-3 and PD-1 were increased on peripheral blood CD4⁺ and CD8⁺ T cells from anti-IL-7Rα-treated mice. Expression of these receptors contributed to reduced T cell cytokine production in response to TCR stimulation. In addition, the frequency of Tregs within the circulating CD4⁺ T cells was increased at the end of anti-IL-7Rα antibody treatment and these Tregs showed a more activated phenotype. In vitro restimulation assays revealed that effector T cells from anti-IL-7Rα-treated mice were more sensitive to co-inhibitory receptor induction after TCR stimulation. Importantly, these changes were accompanied by delayed type 1 diabetes disease kinetics.

CONCLUSIONS

Together, our data show that short-term blockade of IL-7Rα induces detectable changes in co-inhibitory receptor expression and Treg frequencies in peripheral blood of NOD mice. These changes appear to have long-lasting effects by delaying or preventing type 1 diabetes incidence. Hence, our study provides further support for using anti-IL-7Rα antibodies to modulate autoreactive T cell responses.

Emerging Skin T-Cell Functions in Response to Environmental Insults

Skin is the primary barrier between the body and the outside world, functioning not only as a physical barrier, but also as an immunologic first line of defense. A large number of T cells populate the skin. This review highlights the ability of these cutaneous T cells to regulate skin-specific environmental threats, including microbes, injuries, solar UV radiation, and allergens. Since much of this knowledge has been advanced from murine studies, we focus our review on how the mouse state has informed the human state, emphasizing the key parallels and differences.

Blockade of IL-7Rα alleviates collagen-induced arthritis via inhibiting Th1 cell differentiation and CD4+ T cell migration

T cell response is crucial to the pathogenesis and progression of rheumatoid arthritis (RA). IL-7/IL-7R axis has significant effect on CD4⁺ T cell response, including proliferation, differentiation, survival and migration. However, whether blockade of IL-7/IL-7R axis signaling can relieve RA and what is the potential treatment mechanisms are still remaining unclear. In this paper, we established collagen-induced arthritis (CIA) model and observed the effect of IL-7Rα antibody in the treatment of CIA mice. It is demonstrated that IL-7Rα antibody significantly alleviated clinical symptoms of CIA mice, accompanied with reduced CD4⁺ T cell number in both spleen and joints. Decreased CII-specific CD4⁺ T cell proliferation and reduced mRNA expression of inflammatory cytokines in IL-7Rα antibody-treated mice were observed. Subsequently, IL-7Rα antibody treatment in vivo downregulated the percentages of Th1 and Th17 cells and the mRNA expression of T-bet and RORγt gene. Moreover, it was found that IL-7 promoted Th1 cell differentiation in vitro, while having no effect on Th17 cell differentiation. In addition, administration of IL-7Rα antibody reduced the mRNA expression of chemokine receptors (CCR7, CXCR3, CXCR6 and XCR1) on CD4⁺ T cells and chemokine CXCL2 in joints. The results suggested that IL-7Rα antibody treated CIA mice via the inhibition of CII-specific CD4⁺ T cell proliferation, the reduction of Th1 cell differentiation and the restrain of CD4⁺ T cell migration to joint lesion site. This investigation indicates that IL-7Rα is a potential therapeutic target for RA.