RESUMO
Metabolic programming is important for B cell fate, but the bioenergetic requirement for regulatory B (Breg) cell differentiation and function is unknown. Here we show that Breg cell differentiation, unlike non-Breg cells, relies on mitochondrial electron transport and homeostatic levels of reactive oxygen species (ROS). Single-cell RNA sequencing analysis revealed that TXN, encoding the metabolic redox protein thioredoxin (Trx), is highly expressed by Breg cells, unlike Trx inhibitor TXNIP which was downregulated. Pharmacological inhibition or gene silencing of TXN resulted in mitochondrial membrane depolarization and increased ROS levels, selectively suppressing Breg cell differentiation and function while favoring pro-inflammatory B cell differentiation. Patients with systemic lupus erythematosus (SLE), characterized by Breg cell deficiencies, present with B cell mitochondrial membrane depolarization, elevated ROS and fewer Trx+ B cells. Exogenous Trx stimulation restored Breg cells and mitochondrial membrane polarization in SLE B cells to healthy B cell levels, indicating Trx insufficiency underlies Breg cell impairment in patients with SLE.
Assuntos
Proteínas de Transporte , Diferenciação Celular , Lúpus Eritematoso Sistêmico , Mitocôndrias , Espécies Reativas de Oxigênio , Tiorredoxinas , Tiorredoxinas/metabolismo , Tiorredoxinas/genética , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Mitocôndrias/metabolismo , Feminino , Animais , Camundongos , Potencial da Membrana Mitocondrial , Masculino , Adulto , OxirreduçãoRESUMO
Systemic lupus erythematosus (SLE) is characterized by increased expression of type I interferon (IFN)-regulated genes in 50%-75% of patients. We report that out of 501 patients with SLE analyzed, 73 (14%) present autoantibodies against IFNα (anti-IFN-Abs). The presence of neutralizing-anti-IFN-Abs in 4.2% of patients inversely correlates with low circulating IFNα protein levels, inhibition of IFN-I downstream gene signatures, and inactive global disease score. Hallmarks of SLE pathogenesis, including increased immature, double-negative plasmablast B cell populations and reduction in regulatory B cell (Breg) frequencies, were normalized in patients with neutralizing anti-IFN-Abs compared with other patient groups. Immunoglobulin G (IgG) purified from sera of patients with SLE with neutralizing anti-IFN-Abs impedes CpGC-driven IFNα-dependent differentiation of B cells into immature B cells and plasmablasts, thus recapitulating the neutralizing effect of anti-IFN-Abs on B cell differentiation in vitro. Our findings highlight a role for neutralizing anti-IFN-Abs in controlling SLE pathogenesis and support the use of IFN-targeting therapies in patients with SLE lacking neutralizing-anti-IFN-Abs.
Assuntos
Subpopulações de Linfócitos B , Interferon Tipo I , Lúpus Eritematoso Sistêmico , Humanos , Autoanticorpos , Subpopulações de Linfócitos B/metabolismo , Interferon-alfa/uso terapêutico , Interferon-alfa/genética , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/genéticaRESUMO
Regulatory B cells (Bregs) have immunosuppressive capacity, primarily via the production of IL-10. IL-10 expression and immunosuppression have been described in a number of human B cell subsets, two of which include the CD19+CD24hiCD38hi and CD19+CD24hiCD27+ populations. In this chapter, we describe how to identify and isolate these subsets from peripheral blood B cells via flow cytometry. We also explain how to expand Bregs in culture and how to identify them based on intracellular expression of IL-10.
