RESUMO
Activated T cells undergo metabolic reprogramming and effector-cell differentiation but the factors involved are unclear. Utilizing mice lacking DUSP6 (DUSP6-/-), we show that this phosphatase regulates T cell receptor (TCR) signaling to influence follicular helper T (TFH) cell differentiation and T cell metabolism. In vitro, DUSP6-/- CD4+ TFH cells produced elevated IL-21. In vivo, TFH cells were increased in DUSP6-/- mice and in transgenic OTII-DUSP6-/- mice at steady state. After immunization, DUSP6-/- and OTII-DUSP6-/- mice generated more TFH cells and produced more antigen-specific IgG2 than controls. Activated DUSP6-/- T cells showed enhanced JNK and p38 phosphorylation but impaired glycolysis. JNK or p38 inhibitors significantly reduced IL-21 production but did not restore glycolysis. TCR-stimulated DUSP6-/- T cells could not induce phosphofructokinase activity and relied on glucose-independent fueling of mitochondrial respiration. Upon CD28 costimulation, activated DUSP6-/- T cells did not undergo the metabolic commitment to glycolysis pathway to maintain viability. Unexpectedly, inhibition of fatty acid oxidation drastically lowered IL-21 production in DUSP6-/- TFH cells. Our findings suggest that DUSP6 connects TCR signaling to activation-induced metabolic commitment toward glycolysis and restrains TFH cell differentiation via inhibiting IL-21 production.
Assuntos
Diferenciação Celular/fisiologia , Fosfatase 6 de Especificidade Dupla , Glicólise/fisiologia , Receptores de Antígenos de Linfócitos T , Transdução de Sinais/fisiologia , Linfócitos T Auxiliares-Indutores , Animais , Formação de Anticorpos/fisiologia , Antígenos CD28/genética , Antígenos CD28/imunologia , Antígenos CD28/metabolismo , Fosfatase 6 de Especificidade Dupla/genética , Fosfatase 6 de Especificidade Dupla/imunologia , Fosfatase 6 de Especificidade Dupla/metabolismo , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Interleucinas/genética , Interleucinas/imunologia , Interleucinas/metabolismo , MAP Quinase Quinase 4/genética , MAP Quinase Quinase 4/imunologia , MAP Quinase Quinase 4/metabolismo , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/imunologia , Mitocôndrias/metabolismo , Consumo de Oxigênio/fisiologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Auxiliares-Indutores/citologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
INTRODUCTION: Multiple sclerosis (MS) is a complex neurodegenerative disorder that affects the brain and spinal cord. In this study, we applied a deep learning-based approach using the StyleGAN model to explore patterns related to MS and predict disease progression in magnetic resonance images (MRI). METHODS: We trained the StyleGAN model unsupervised using T1-weighted GRE MR images and diffusion-based ADC maps of MS patients and healthy controls. We then used the trained model to resample MR images from real input data and modified them by manipulations in the latent space to simulate MS progression. We analyzed the resulting simulation-related patterns mimicking disease progression by comparing the intensity profiles of the original and manipulated images and determined the brain parenchymal fraction (BPF). RESULTS: Our results show that MS progression can be simulated by manipulating MR images in the latent space, as evidenced by brain volume loss on both T1-weighted and ADC maps and increasing lesion extent on ADC maps. CONCLUSION: Overall, this study demonstrates the potential of the StyleGAN model in medical imaging to study image markers and to shed more light on the relationship between brain atrophy and MS progression through corresponding manipulations in the latent space.
Assuntos
Progressão da Doença , Imageamento por Ressonância Magnética , Esclerose Múltipla , Humanos , Esclerose Múltipla/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Adulto , Masculino , Feminino , Encéfalo/diagnóstico por imagem , Aprendizado Profundo , Pessoa de Meia-Idade , Processamento de Imagem Assistida por Computador/métodosRESUMO
Phosphatase and tensin homolog (PTEN) is vital for B cell development, acting as a key negative regulator in the PI3K signaling pathway. We used CD23-cre to generate PTEN-conditional knockout mice (CD23-cKO) to examine the impact of PTEN mutation on peripheral B cells. Unlike mb1-cre-mediated PTEN deletion in early B cells, CD23-cKO mutants exhibited systemic inflammation with increased IL-6 production in mature B cells upon CpG stimulation. Inflammatory B cells in CD23-cKO mice showed elevated phosphatidylinositol 3-phosphate [PI(3)P] levels and increased TLR9 endosomal localization. Pharmacological inhibition of PI(3)P synthesis markedly reduced TLR9-mediated IL-6. Single-cell RNA-sequencing (RNA-seq) revealed altered endocytosis, BANK1, and NF-κB1 expression in PTEN-deficient B cells. Ectopic B cell receptor (BCR) expression on non-inflammatory mb1-cKO B cells restored BANK1 and NF-κB1 expression, enhancing TLR9-mediated IL-6 production. Our study highlights PTEN as a crucial inflammatory checkpoint, regulating TLR9/IL-6 axis by fine-tuning PI(3)P homeostasis. Additionally, BCR downregulation prevents the differentiation of inflammatory B cells in PTEN deficiency.
RESUMO
Chronic kidney disease (CKD) is a global public health issue. CKD is caused by the infiltration of various myeloid cell types into renal tissue, resulting in renal fibrosis and tubular atrophy. Unilateral ureteral obstruction (UUO) surgery in mice is a model of CKD and characterized by high expression of the anti-inflammatory receptor, Triggering receptor expressed on myeloid cells 2 (TREM-2), on myeloid cells in affected kidneys. Here, we show that iNOS expression and nitric oxide (NO) induction were decreased in Trem-2-/- bone marrow-derived DCs (BMDCs) and in Trem-2 knockdown DC2.4 cells stimulated in vitro with LPS. The nitration of RORγt was decreased in T cells co-cultured with LPS-stimulated Trem-2-/- BMDCs, enhancing IL-17 production. UUO-treated Trem-2-/- mice displayed aggravated renal pathogenesis accompanied by greater neutrophil infiltration and enhanced Th17 cells differentiation, phenotypes that could be rescued by the administration of L-arginine (a biological precursor of NO). Our data identify a key mechanism underlying TREM-2-mediated NO to modulate the cellular crosstalk between dendritic cells, Th17, and neutrophils. Furthermore, we also reveal TREM-2 as a potential novel target for the development of anti-inflammatory drugs in CKD treatment. KEY MESSAGES: The expression of TREM-2 is increased in nephritis TREM-2+ DCs maintain NO production to negatively regulate Th17 differentiation The severe pathologies of nephritis can be rescued by L-arginine supplementation.
Assuntos
Glicoproteínas de Membrana/metabolismo , Nefrite , Receptores Imunológicos/metabolismo , Insuficiência Renal Crônica , Obstrução Ureteral , Animais , Arginina , Células Dendríticas/patologia , Lipopolissacarídeos , Camundongos , Nefrite/complicações , Óxido Nítrico , Células Th17/patologia , Obstrução Ureteral/patologiaRESUMO
The serine/threonine phosphatase PP4 has been implicated in DNA damage repair and cell cycle regulation through its dephosphorylation of specific substrates. We previously showed that PP4 is required for mouse B cell development, germinal center (GC) formation and immunoglobulin (Ig) class switch recombination (CSR). Here, we investigate the mechanisms underlying this requirement and demonstrate that murine PP4-deficient B lymphocytes have a defect in cell proliferation. Strikingly, the DNA damage response pathway that involves ATM/p53 and is linked to cell cycle arrest and impaired cell survival is strongly induced in these mutant B cells. In response to LPS + IL-4, stimuli that trigger IgG1 production, these PP4-deficient B cells show inefficient phosphorylation of ATR, leading to reduced retention of γH2AX-NBS1 complexes at sites of DNA damage, and compromised switching to IgG1. However, beyond the cell proliferation phase, conditional deletion of PP4 under the control of AID/cre completely restores normal IgG1 production in mutant B cell cultures. In vivo, co-deletion of PP4 and p53 by AID/cre partially rescues switching to IgG1 in B cells of mice immunized with TNP-KLH. Our findings establish that PP4 is indispensable for preventing DNA replication stress that could interfere with CSR, thereby promoting antibody switching during the humoral immune response.
Assuntos
Replicação do DNA , Switching de Imunoglobulina , Fosfoproteínas Fosfatases/deficiência , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Proliferação de Células , Células Cultivadas , Switching de Imunoglobulina/genética , Switching de Imunoglobulina/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/metabolismoRESUMO
C5L2 is a receptor that binds to C5a and belongs to the family of G protein-coupled receptors, but its role in physiological C5a-mediated responses remains under debate. Here we show that, like the canonical C5a receptor C5aR, C5L2 plays a pro-inflammatory role in a murine model of acute experimental colitis. We demonstrate that C5L2 physically interacts with C5aR and is required for optimal C5a-mediated C5aR internalization and associated ERK activation. Abrogation of C5a-induced receptor internalization by treatment with the dynamin inhibitor dynasore(TM) impaired C5a-induced MEK and ERK signaling. Although the presence of C5aR alone was sufficient to recruit the scaffold protein ß-arrestin1 to the cell membrane in response to C5a stimulation, it was inadequate to mediate AP2 recruitment and subsequent C5aR internalization. Expression of C5L2 allowed normal internalization of C5aR in response to C5a stimulation, followed by normal ERK signaling. Thus, our work reveals an essential role for C5L2 in C5a-triggered, AP2-dependent C5aR internalization and downstream ERK signaling.