CD9+ Regulatory B Cells Induce T Cell Apoptosis via IL-10 and Are Reduced in Severe Asthmatic Patients

CD9 was recently identified as a marker of murine IL-10-competent regulatory B cells. Functional impairments or defects in CD9+ IL-10-secreting regulatory B cells are associated with enhanced asthma-like inflammation and airway hyperresponsiveness. In mouse models, all asthma-related features can be abrogated by CD9+ B cell adoptive transfer. We aimed herein to decipher the profiles, features, and molecular mechanisms of the regulatory properties of CD9+ B cells in human and mouse. The profile of CD9+ B cells was analyzed using blood from severe asthmatic patients and normal and asthmatic mice by flow cytometry. The regulatory effects of mouse CD9+ B cells on effector T cell death, cell cycle arrest, apoptosis, and mitochondrial depolarization were determined using yellow dye, propidium iodide, Annexin V, and JC-1 staining. MAPK phosphorylation was analyzed by western blotting. Patients with severe asthma and asthmatic mice both harbored less CD19+CD9+ B cells, although these cells displayed no defect in their capacity to induce T cell apoptosis. Molecular mechanisms of regulation of CD9+ B cells characterized in mouse showed that they induced effector T cell cycle arrest in sub G0/G1, leading to apoptosis in an IL-10-dependent manner. This process occurred through MAPK phosphorylation and activation of both the intrinsic and extrinsic pathways. This study characterizes the molecular mechanisms underlying the regulation of CD9+ B cells to induce effector T cell apoptosis in mice and humans via IL-10 secretion. Defects in CD9+ B cells in blood from patients with severe asthma reveal new insights into the lack of regulation of inflammation in these patients

C5aR2 regulates STING-mediated interferon beta production in human macrophages

The complement system mediates diverse regulatory immunological functions. C5aR2, an enigmatic receptor for anaphylatoxin C5a, has been shown to modulate PRR-dependent pro-inflammatory cytokine secretion in human macrophages. However, the specific downstream targets and underlying molecular mechanisms are less clear. In this study, CRISPR-Cas9 was used to generate macrophage models lacking C5aR2, which were used to probe the role of C5aR2 in the context of PRR stimulation. cGAS and STING-induced IFN-β secretion was significantly increased in C5aR2 KO THP-1 cells and C5aR2-edited primary human monocyte-derived macrophages, and STING and IRF3 expression were increased, albeit not significantly, in C5aR2 KO cell lines implicating C5aR2 as a regulator of the IFN-β response to cGAS-STING pathway activation. Transcriptomic analysis by RNAseq revealed that nucleic acid sensing and antiviral signalling pathways were significantly up-regulated in C5aR2 KO THP-1 cells. Altogether, these data suggest a link between C5aR2 and nucleic acid sensing in human macrophages. With further characterisation, this relationship may yield therapeutic options in interferon-related pathologies

The neutron and its role in cosmology and particle physics

Experiments with cold and ultracold neutrons have reached a level of precision such that problems far beyond the scale of the present Standard Model of particle physics become accessible to experimental investigation. Due to the close links between particle physics and cosmology, these studies also permit a deep look into the very first instances of our universe. First addressed in this article, both in theory and experiment, is the problem of baryogenesis ... The question how baryogenesis could have happened is open to experimental tests, and it turns out that this problem can be curbed by the very stringent limits on an electric dipole moment of the neutron, a quantity that also has deep implications for particle physics. Then we discuss the recent spectacular observation of neutron quantization in the earth's gravitational field and of resonance transitions between such gravitational energy states. These measurements, together with new evaluations of neutron scattering data, set new constraints on deviations from Newton's gravitational law at the picometer scale. Such deviations are predicted in modern theories with extra-dimensions that propose unification of the Planck scale with the scale of the Standard Model ... Another main topic is the weak-interaction parameters in various fields of physics and astrophysics that must all be derived from measured neutron decay data. Up to now, about 10 different neutron decay observables have been measured, much more than needed in the electroweak Standard Model. This allows various precise tests for new physics beyond the Standard Model, competing with or surpassing similar tests at high-energy. The review ends with a discussion of neutron and nuclear data required in the synthesis of the elements during the "first three minutes" and later on in stellar nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic

Study of lymphocyte regulation in lung and kidney transplantation

La transplantation s’accompagne aujourd’hui systematiquement de traitements immunosuppresseurs qui inhibent la reponse alloimmune dirigee contre le greffon afin d’eviter son rejet. Cependant, ces traitements lourds ont de nombreux effets deleteres et ne permettent pas de controler efficacement la survenue du rejet chronique a long terme. L’objectif de ce travail de these, base sur deux situations cliniques distinctes, s’inscrit dans deux axes prioritaires de la recherche en transplantation : (1) identifier des marqueurs predictifs de la perte de fonction des greffons pulmonaires et (2) decrypter les mecanismes de l’acceptation des greffons renaux dans une situation de tolerance operationnelle. Tout d’abord, nous avons etudie les mecanismes de l’acceptation du greffon, chez des patients transplantes renaux presentant un greffon fonctionnel en l’absence de traitement immunosuppresseur. Nous avons identifie chez ces patients une proportion plus importante de lymphocytes T regulateurs memoires circulants, ayant la capacite de degrader l’ATP extracellulaire et favoriser un etat protolerogenique. Ce mecanisme, defaillant chez les patients stables sous traitement, pourrait participer au maintien d’un greffon renal fonctionnel chez les patients tolerants non traites. Dans un second temps, nous nous sommes interesses, chez des patients transplantes pulmonaire, a la prediction de la survenue du rejet chronique. Nous avons mis en evidence un profil lymphocytaire T regulateur modifie chez les patients qui developperont un rejet chronique a long-terme. Le suivi de ce biomarqueur pourrait permettre une meilleure identification des patients a risque de rejet.Transplantation is nowadays systematically associated with the administration of immunosuppressive treatments inhibiting the allo-immune response toward the graft to prevent the rejection by the recipient's immune system. However, these heavy treatments have several deleterious effects and are not able to control longterm chronic rejection development. Thus, the objective of this PhD work, based on two distinct clinical situations, is part of two priority axes of transplant research: (1) identify early predictive markers of long-term lung allograft dysfunction and (2) decipher the mechanisms involved in the acceptance of kidney allograft in operational tolerance. We first investigated the mechanisms of graft acceptance in kidney transplanted patients with a functional graft in the absence of immunosuppressive therapy. We identified in these patients a greater proportion of circulating memory regulatory T lymphocytes, with an increased ability to degrade extracellular ATP, a pro-inflammatory mediator, and favour a protolerogenic environment. Thus, this mechanism, not efficient in stable patients under treatments, could participate in the inhibition of the allo-immune response leading to maintaining a functional kidney graft in the absence of immunosuppression. In a second time, we interested in the prediction of chronic rejection occurrence in lung transplanted patients. We report that the early posttransplant regulatory T lymphocyte profile is modified in patients who will develop chronic rejection in the 3 years. Thus, monitoring this predictive biomarker could allow a better identification of patients at risk of rejection

CD9+ Regulatory B Cells Induce T Cell Apoptosis via IL-10 and Are Reduced in Severe Asthmatic Patients

International audienceCD9 was recently identified as a marker of murine IL-10-competent regulatory B cells. Functional impairments or defects in CD9 + IL-10-secreting regulatory B cells are associated with enhanced asthma-like inflammation and airway hyperresponsiveness. In mouse models, all asthma-related features can be abrogated by CD9 + B cell adoptive transfer. We aimed herein to decipher the profiles, features, and molecular mechanisms of the regulatory properties of CD9 + B cells in human and mouse. The profile of CD9 + B cells was analyzed using blood from severe asthmatic patients and normal and asthmatic mice by flow cytometry. The regulatory effects of mouse CD9 + B cells on effector T cell death, cell cycle arrest, apoptosis, and mitochondrial depolarization were determined using yellow dye, propidium iodide, Annexin V, and JC-1 staining. MAPK phosphorylation was analyzed by western blotting. Patients with severe asthma and asthmatic mice both harbored less CD19 + CD9 + B cells, although these cells displayed no defect in their capacity to induce T cell apoptosis. Molecular mechanisms of regulation of CD9 + B cells characterized in mouse showed that they induced effector T cell cycle arrest in sub G0/G1, leading to apoptosis in an IL-10-dependent manner. This process occurred through MAPK phosphorylation and activation of both the intrinsic and extrinsic pathways. This study characterizes the molecular mechanisms underlying the regulation of CD9 + B cells to induce effector T cell apoptosis in mice and humans via IL-10 secretion. Defects in CD9 + B cells in blood from patients with severe asthma reveal new insights into the lack of regulation of inflammation in these patients

High circulating CD4+CD25[hi]FOXP3+ T cell subpopulation early after lung transplantation is associated with development of BOS

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Increased degradation of ATP is driven by memory~regulatory T cells in kidney transplantation tolerance

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GZMB+ B cells, a key factor of cell immunity in human?

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A composite score associated with spontaneous operational tolerance in kidney transplant recipients

International audienceNew challenges in renal transplantation include using biological information to devise a useful clinical test for discerning high- and low-risk patients for individual therapy and ascertaining the best combination and appropriate dosages of drugs. Based on a 20-gene signature from a microarray meta-analysis performed on 46 operationally tolerant patients and 266 renal transplant recipients with stable function, we applied the sparse Bolasso methodology to identify a minimal and robust combination of six genes and two demographic parameters associated with operational tolerance. This composite score of operational tolerance discriminated operationally tolerant patients with an area under the curve of 0.97 (95% confidence interval 0.94-1.00). The score was not influenced by immunosuppressive treatment, center of origin, donor type, or post-transplant lymphoproliferative disorder history of the patients. This composite score of operational tolerance was significantly associated with both de novo anti-HLA antibodies and tolerance loss. It was validated by quantitative polymerase chain reaction using independent samples and demonstrated specificity toward a model of tolerance induction. Thus, our score would allow clinicians to improve follow-up of patients, paving the way for individual therapy

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

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