RESUMO
The intricate immune mechanisms governing mucosal healing following intestinal damage induced by cytotoxic drugs remain poorly understood. The goal of this study was to investigate the role of lymphotoxin beta receptor (LTßR) signaling in chemotherapy-induced intestinal damage. LTßR deficient mice exhibited heightened body weight loss, exacerbated intestinal pathology, increased proinflammatory cytokine expression, reduced IL-22 expression, and proliferation of intestinal epithelial cells following methotrexate (MTX) treatment. Furthermore, LTßR-/-IL-22-/- mice succumbed to MTX treatment, suggesting that LTßR- and IL-22- dependent pathways jointly promote mucosal repair. Although both LTßR ligands LIGHT and LTß were upregulated in the intestine early after MTX treatment, LIGHT-/- mice, but not LTß-/- mice, displayed exacerbated disease. Further, we revealed the critical role of T cells in mucosal repair as T cell-deficient mice failed to upregulate intestinal LIGHT expression and exhibited increased body weight loss and intestinal pathology. Analysis of mice with conditional inactivation of LTßR revealed that LTßR signaling in intestinal epithelial cells, but not in Lgr5+ intestinal stem cells, macrophages or dendritic cells was critical for mucosal repair. Furthermore, inactivation of the non-canonical NF-kB pathway member RelB in intestinal epithelial cells promoted MTX-induced disease. Based on these results, we propose a model wherein LIGHT produced by T cells activates LTßR-RelB signaling in intestinal epithelial cells to facilitate mucosal repair following chemotherapy treatment.
Assuntos
Mucosa Intestinal , Receptor beta de Linfotoxina , Metotrexato , Camundongos Knockout , Transdução de Sinais , Fator de Transcrição RelB , Animais , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Mucosa Intestinal/efeitos dos fármacos , Receptor beta de Linfotoxina/metabolismo , Receptor beta de Linfotoxina/genética , Camundongos , Fator de Transcrição RelB/metabolismo , Fator de Transcrição RelB/genética , Metotrexato/efeitos adversos , Células Epiteliais/metabolismo , Camundongos Endogâmicos C57BL , Interleucina 22 , Interleucinas/metabolismo , Interleucinas/genéticaRESUMO
Tumor necrosis factor (TNF) is one of many cytokines - protein molecules responsible for communication between the cells of immune system. TNF was discovered and given its grand name because of its striking antitumor effects in experimental systems, but its main physiological functions in the context of whole organism turned out to be completely unrelated to protection against tumors. This short review discusses "man-made" mouse models generated by early genome-editing technologies, which enabled us to establish true functions of TNF in health and certain diseases as well as to unravel potential strategies for improving therapy of TNF-dependent diseases.
Assuntos
Fator de Necrose Tumoral alfa , Animais , Humanos , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Camundongos , Edição de Genes/métodos , Neoplasias/imunologia , Neoplasias/genética , Neoplasias/terapiaRESUMO
Mechanisms of sex-dependent orofacial pain are widely understudied. A significant gap in knowledge exists about comprehensive regulation of tissue-specific trigeminal sensory neurons in diseased state of both sexes. Using RNA sequencing of FACS sorted retro-labeled sensory neurons innervating tongue tissue, we determined changes in transcriptomic profiles in males and female mice under naïve as well as tongue-tumor bearing conditions Our data revealed the following interesting findings: (1) FACS sorting obtained higher number of neurons from female trigeminal ganglia (TG) compared to males; (2) Naïve female neurons innervating the tongue expressed immune cell markers such as Csf1R, C1qa and others, that weren't expressed in males. This was validated by Immunohistochemistry. (3) Accordingly, immune cell markers such as Csf1 exclusively sensitized TRPV1 responses in female TG neurons. (4) Male neurons were more tightly regulated than female neurons upon tumor growth and very few differentially expressed genes (DEGs) overlapped between the sexes, (5) Male DEGs contained higher number of transcription factors whereas female DEGs contained higher number of enzymes, cytokines and chemokines. Collectively, this is the first study to characterize the effect of sex as well as of tongue-tumor on global gene expression, pathways and molecular function of tongue-innervating sensory neurons.
Assuntos
Células Receptoras Sensoriais , Língua , Camundongos , Masculino , Feminino , Animais , Língua/metabolismo , Gânglio Trigeminal/metabolismo , Caracteres Sexuais , Biomarcadores/metabolismo , GenômicaRESUMO
Systemic inflammation halts lymphopoiesis and prioritizes myeloid cell production. How blood cell production switches from homeostasis to emergency myelopoiesis is incompletely understood. Here, we show that lymphotoxin-ß receptor (LTßR) signaling in combination with TNF and IL-1 receptor signaling in bone marrow mesenchymal stem cells (MSCs) down-regulates Il7 expression to shut down lymphopoiesis during systemic inflammation. LTßR signaling in MSCs also promoted CCL2 production during systemic inflammation. Pharmacological or genetic blocking of LTßR signaling in MSCs partially enabled lymphopoiesis and reduced monocyte numbers in the spleen during systemic inflammation, which correlated with reduced survival during systemic bacterial and viral infections. Interestingly, lymphotoxin-α1ß2 delivered by B-lineage cells, and specifically by mature B cells, contributed to promote Il7 down-regulation and reduce MSC lymphopoietic activity. Our studies revealed an unexpected role of LTßR signaling in MSCs and identified recirculating mature B cells as an important regulator of emergency myelopoiesis.
Assuntos
Células-Tronco Mesenquimais , Mielopoese , Humanos , Interleucina-7 , Linfócitos B/metabolismo , Células-Tronco Mesenquimais/metabolismo , Inflamação/metabolismoRESUMO
BACKGROUND: Dysregulation of airway smooth muscle cells (ASM) is central to the severity of asthma. Which molecules dominantly control ASM in asthma is unclear. High levels of the cytokine LIGHT (aka TNFSF14) have been linked to asthma severity and lower baseline predicted FEV1 percentage, implying that signals through its receptors might directly control ASM dysfunction. OBJECTIVE: Our study sought to determine whether signaling via lymphotoxin beta receptor (LTßR) or herpesvirus entry mediator from LIGHT dominantly drives ASM hyperreactivity induced by allergen. METHODS: Conditional knockout mice deficient for LTßR or herpesvirus entry mediator in smooth muscle cells were used to determine their role in ASM deregulation and airway hyperresponsiveness (AHR) in vivo. Human ASM were used to study signals induced by LTßR. RESULTS: LTßR was strongly expressed in ASM from normal and asthmatic subjects compared to several other receptors implicated in smooth muscle deregulation. Correspondingly, conditional deletion of LTßR only in smooth muscle cells in smMHCCreLTßRfl/fl mice minimized changes in their numbers and mass as well as AHR induced by house dust mite allergen in a model of severe asthma. Intratracheal LIGHT administration independently induced ASM hypertrophy and AHR in vivo dependent on direct LTßR signals to ASM. LIGHT promoted contractility, hypertrophy, and hyperplasia of human ASM in vitro. Distinguishing LTßR from the receptors for IL-13, TNF, and IL-17, which have also been implicated in smooth muscle dysregulation, LIGHT promoted NF-κB-inducing kinase-dependent noncanonical nuclear factor kappa-light-chain enhancer of activated B cells in ASM in vitro, leading to sustained accumulation of F-actin, phosphorylation of myosin light chain kinase, and contractile activity. CONCLUSIONS: LTßR signals directly and dominantly drive airway smooth muscle hyperresponsiveness relevant for pathogenesis of airway remodeling in severe asthma.
Assuntos
Asma , Membro 14 de Receptores do Fator de Necrose Tumoral , Humanos , Camundongos , Animais , Receptor beta de Linfotoxina/genética , Asma/patologia , Músculo Liso , Miócitos de Músculo Liso/patologia , Camundongos Knockout , Alérgenos , Pulmão/patologiaRESUMO
Gain-of-function (GOF) mutations in CXCR4 cause WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome, characterized by infections, leukocyte retention in bone marrow (BM), and blood leukopenias. B lymphopenia is evident at early progenitor stages, yet why do CXCR4 GOF mutations that cause B (and T) lymphopenia remain obscure? Using a CXCR4 R334X GOF mouse model of WHIM syndrome, we showed that lymphopoiesis is reduced because of a dysregulated mesenchymal stem cell (MSC) transcriptome characterized by a switch from an adipogenic to an osteolineage-prone program with limited lymphopoietic activity. We identify lymphotoxin beta receptor (LTßR) as a critical pathway promoting interleukin-7 (IL-7) down-regulation in MSCs. Blocking LTßR or CXCR4 signaling restored IL-7 production and B cell development in WHIM mice. LTßR blocking also increased production of IL-7 and B cell activating factor (BAFF) in secondary lymphoid organs (SLOs), increasing B and T cell numbers in the periphery. These studies revealed that LTßR signaling in BM MSCs and SLO stromal cells limits the lymphocyte compartment size.
Assuntos
Síndromes de Imunodeficiência , Linfopenia , Animais , Fator Ativador de Células B , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/genética , Interleucina-7 , Receptor beta de Linfotoxina , Camundongos , Doenças da Imunodeficiência Primária , Nicho de Células-Tronco , Linfócitos T , VerrugasRESUMO
TNF and LTα are structurally related cytokines of the TNF superfamily. Their genes are located in close proximity to each other and to the Ltb gene within the TNF/LT locus inside MHC. Unlike Ltb, transcription of Tnf and of Lta is tightly controlled, with the Tnf gene being an immediate early gene that is rapidly induced in response to various inflammatory stimuli. Genes of the TNF/LT locus play a crucial role in lymphoid tissue organogenesis, although some aspects of their specific contribution remain controversial. Here, we present new findings and discuss the distinct contribution of TNF produced by ILC3 cells to Peyer's patch organogenesis.
Assuntos
Linfotoxina-alfa , Nódulos Linfáticos Agregados , Animais , Tecido Linfoide , Camundongos , Camundongos Knockout , Organogênese/genética , Fatores de Necrose Tumoral/metabolismoRESUMO
Infection with Orientia tsutsugamushi, an obligate intracellular bacterium, can cause mild or severe scrub typhus. Some patients develop acute lung injury, multi-organ failure, and fatal infection; however, little is known regarding key immune mediators that mediate infection control or disease pathogenesis. Using murine models of scrub typhus, we demonstrated in this study the requirement of TNF-TNFR signaling in protective immunity against this infection. Mice lacking both TNF receptors (TNFR1 and TNFR2) were highly susceptible to O. tsutsugamushi infection, displaying significantly increased tissue bacterial burdens and succumbing to infection by day 9, while most wild-type mice survived through day 20. This increased susceptibility correlated with poor activation of cellular immunity in inflamed tissues. Flow cytometry of lung- and spleen-derived cells revealed profound deficiencies in total numbers and activation status of NK cells, neutrophils, and macrophages, as well as CD4 and CD8 T cells. To define the role of individual receptors in O. tsutsugamushi infection, we used mice lacking either TNFR1 or TNFR2. While deficiency in either receptor alone was sufficient to increase host susceptibility to the infection, TNFR1 and TNFR2 played a distinct role in cellular responses. TNF signaling through TNFR1 promoted inflammatory responses and effector T cell expansion, while TNFR2 signaling was associated with anti-inflammatory action and tissue homeostasis. Moreover, TNFRs played an intrinsic role in CD8+ T cell activation, revealing an indispensable role of TNF in protective immunity against O. tsutsugamushi infection.
Assuntos
Orientia tsutsugamushi , Receptores Tipo II do Fator de Necrose Tumoral , Receptores Tipo I de Fatores de Necrose Tumoral , Tifo por Ácaros , Animais , Camundongos , Camundongos Endogâmicos C57BL , Receptores Tipo I de Fatores de Necrose Tumoral/imunologia , Receptores Tipo II do Fator de Necrose Tumoral/imunologia , Tifo por Ácaros/imunologiaRESUMO
Lymphotoxin beta receptor (LTßR) is a promising therapeutic target in autoimmune and infectious diseases as well as cancer. Mice with genetic inactivation of LTßR display multiple defects in development and organization of lymphoid organs, mucosal immune responses, IgA production and an autoimmune phenotype. As these defects are imprinted in embryogenesis and neonate stages, the impact of LTßR signaling in adulthood remains unclear. Here, to overcome developmental defects, we generated mice with inducible ubiquitous genetic inactivation of LTßR in adult mice (iLTßRΔ/Δ mice) and redefined the role of LTßR signaling in organization of lymphoid organs, immune response to mucosal bacterial pathogen, IgA production and autoimmunity. In spleen, postnatal LTßR signaling is required for development of B cell follicles, follicular dendritic cells (FDCs), recruitment of neutrophils and maintenance of the marginal zone. Lymph nodes of iLTßRΔ/Δ mice were reduced in size, lacked FDCs, and had disorganized subcapsular sinus macrophages. Peyer`s patches were smaller in size and numbers, and displayed reduced FDCs. The number of isolated lymphoid follicles in small intestine and colon were also reduced. In contrast to LTßR-/- mice, iLTßRΔ/Δ mice displayed normal thymus structure and did not develop signs of systemic inflammation and autoimmunity. Further, our results suggest that LTßR signaling in adulthood is required for homeostasis of neutrophils, NK, and iNKT cells, but is dispensable for the maintenance of polyclonal IgA production. However, iLTßRΔ/Δ mice exhibited an increased sensitivity to C. rodentium infection and failed to develop pathogen-specific IgA responses. Collectively, our study uncovers new insights of LTßR signaling in adulthood for the maintenance of lymphoid organs, neutrophils, NK and iNKT cells, and IgA production in response to mucosal bacterial pathogen.
Assuntos
Envelhecimento/imunologia , Tecido Linfoide/imunologia , Receptor beta de Linfotoxina/fisiologia , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/imunologia , Autoimunidade , Moléculas de Adesão Celular/metabolismo , Quimiocinas/metabolismo , Citrobacter rodentium/imunologia , Cruzamentos Genéticos , Regulação da Expressão Gênica no Desenvolvimento , Homeostase/imunologia , Imunoglobulina A/biossíntese , Imunoglobulina A/imunologia , Inflamação , Células Matadoras Naturais/imunologia , Tecido Linfoide/citologia , Receptor beta de Linfotoxina/biossíntese , Receptor beta de Linfotoxina/deficiência , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Endogâmicos MRL lpr , Camundongos Transgênicos , Neutrófilos/imunologia , Deleção de Sequência , Organismos Livres de Patógenos Específicos , Esplenomegalia/imunologiaRESUMO
The spleen contains a myriad of conventional dendritic cell (cDC) subsets that protect against systemic pathogen dissemination by bridging antigen detection to the induction of adaptive immunity. How cDC subsets differentiate in the splenic environment is poorly understood. Here, we report that LTα1ß2-expressing Rorgt+ ILC3s, together with B cells, control the splenic cDC niche size and the terminal differentiation of Sirpα+CD4+Esam+ cDC2s, independently of the microbiota and of bone marrow pre-cDC output. Whereas the size of the splenic cDC niche depended on lymphotoxin signaling only during a restricted time frame, the homeostasis of Sirpα+CD4+Esam+ cDC2s required continuous lymphotoxin input. This latter property made Sirpα+CD4+Esam+ cDC2s uniquely susceptible to pharmacological interventions with LTßR agonists and antagonists and to ILC reconstitution strategies. Together, our findings demonstrate that LTα1ß2-expressing Rorgt+ ILC3s drive splenic cDC differentiation and highlight the critical role of ILC3s as perpetual regulators of lymphoid tissue homeostasis.
Assuntos
Células Dendríticas/imunologia , Imunidade Inata , Tecido Linfoide/imunologia , Linfotoxina-alfa/imunologia , Transdução de Sinais/imunologia , Baço/imunologia , Animais , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/imunologia , Moléculas de Adesão Celular/metabolismo , Células Dendríticas/metabolismo , Feminino , Tecido Linfoide/citologia , Tecido Linfoide/metabolismo , Receptor beta de Linfotoxina/genética , Receptor beta de Linfotoxina/imunologia , Receptor beta de Linfotoxina/metabolismo , Linfotoxina-alfa/genética , Linfotoxina-alfa/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Receptores Imunológicos/metabolismo , Transdução de Sinais/genética , Baço/citologia , Baço/metabolismoRESUMO
Inflammatory bowel disease is characterized by an exacerbated intestinal immune response, but the critical mechanisms regulating immune activation remain incompletely understood. We previously reported that the TNF-superfamily molecule TNFSF14 (LIGHT) is required for preventing severe disease in mouse models of colitis. In addition, deletion of lymphotoxin beta receptor (LTßR), which binds LIGHT, also led to aggravated colitis pathogenesis. Here, we aimed to determine the cell type(s) requiring LTßR and the mechanism critical for exacerbation of colitis. Specific deletion of LTßR in neutrophils (LTßRΔN), but not in several other cell types, was sufficient to induce aggravated colitis and colonic neutrophil accumulation. Mechanistically, RNA-Seq analysis revealed LIGHT-induced suppression of cellular metabolism, and mitochondrial function, that was dependent on LTßR. Functional studies confirmed increased mitochondrial mass and activity, associated with excessive mitochondrial ROS production and elevated glycolysis at steady-state and during colitis. Targeting these metabolic changes rescued exacerbated disease severity. Our results demonstrate that LIGHT signals to LTßR on neutrophils to suppress metabolic activation and thereby prevents exacerbated immune pathogenesis during colitis.
Assuntos
Colite/imunologia , Doenças Inflamatórias Intestinais/imunologia , Receptor beta de Linfotoxina/metabolismo , Mitocôndrias/metabolismo , Neutrófilos/metabolismo , Ativação Metabólica , Animais , Sulfato de Dextrana , Modelos Animais de Doenças , Progressão da Doença , Humanos , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neutrófilos/imunologia , Membro 14 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genéticaRESUMO
Asthma is a common inflammatory disease of the airway caused by a combination of genetic and environmental factors and characterized by airflow obstruction, wheezing, eosinophilia, and neutrophilia of lungs and sputum. Similar to other proinflammatory cytokines, IL-6 is elevated in asthma and plays an active role in this disease. However, the exact molecular mechanism of IL-6 involvement in the pathogenesis of asthma remains largely unknown and the major cellular source of pathogenic IL-6 has not been defined. In the present study, we used conditional gene targeting to demonstrate that macrophages and dendritic cells are the critical sources of pathogenic IL-6 in acute HDM-induced asthma in mice. Complete genetic inactivation of IL-6 ameliorated the disease with significant decrease in eosinophilia in the lungs. Specific ablation of IL-6 in macrophages reduced key indicators of type 2 allergic inflammation, including eosinophil and Th2 cell accumulation in the lungs, production of IgE and expression of asthma-associated inflammatory mediators. In contrast, mice with deficiency of IL-6 in dendritic cells demonstrated attenuated neutrophilic, but regular eosinophilic response in HDM-induced asthma. Taken together, our results indicate that IL-6 plays a pathogenic role in the HDM-induced asthma model and that lung macrophages and dendritic cells are the predominant sources of pathogenic IL-6 but contribute differently to the disease.
Assuntos
Asma/imunologia , Células Dendríticas/imunologia , Interleucina-6/imunologia , Macrófagos/imunologia , Animais , Asma/genética , Asma/patologia , Células Dendríticas/patologia , Modelos Animais de Doenças , Eosinófilos/imunologia , Eosinófilos/patologia , Interleucina-6/genética , Macrófagos/patologia , Camundongos , Camundongos Knockout , Células Th2/imunologia , Células Th2/patologiaRESUMO
The emigration of mature thymocytes from the thymus is critical for establishing peripheral T cell compartments. However, the pathways controlling this process and the timing of egress in relation to postselection developmental stages are poorly defined. Here, we reexamine thymocyte egress and test current and opposing models in relation to the requirement for LTßR, a regulator of thymic microenvironments and thymocyte emigration. Using cell-specific gene targeting, we show that the requirement for LTßR in thymocyte egress is distinct from its control of thymic epithelium and instead maps to expression by endothelial cells. By separating emigration into sequential phases of perivascular space (PVS) entry and transendothelial migration, we reveal a developmentally ordered program of egress where LTßR operates to rate limit access to the PVS. Collectively, we show the process of thymic emigration ensures only the most mature thymocytes leave the thymus and demonstrate a role for LTßR in the initiation of thymus emigration that segregates from its control of medulla organization.
Assuntos
Movimento Celular/imunologia , Células Endoteliais/imunologia , Receptor beta de Linfotoxina/imunologia , Timócitos/imunologia , Timo/imunologia , Animais , Movimento Celular/genética , Células Endoteliais/citologia , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Knockout , Timócitos/citologia , Timo/citologiaRESUMO
The liver has an extraordinary capacity to regenerate through activation of key molecular pathways. However, central regulators controlling liver regeneration remain insufficiently studied. Here, we show that B cell-deficient animals failed to induce sufficient liver regeneration after partial hepatectomy (PHx). Consistently, adoptive transfer of B cells could rescue defective liver regeneration. B cell-mediated lymphotoxin beta production promoted recovery from PHx. Absence of B cells coincided with loss of splenic cluster of differentiation 169-positive (CD169+ ) macrophages. Moreover, depletion of CD169+ cells resulted in defective liver regeneration and decreased survival, which was associated with reduced hepatocyte proliferation. Mechanistically, CD169+ cells contributed to liver regeneration by inducing hepatic interleukin-6 (IL-6) production and signal transducer and activator of transcription 3 activation. Accordingly, treatment of CD169+ cell-depleted animals with IL-6/IL-6 receptor rescued liver regeneration and severe pathology following PHx. Conclusion: We identified CD169+ cells to be a central trigger for liver regeneration, by inducing key signaling pathways important for liver regeneration.
Assuntos
Linfócitos B/fisiologia , Regeneração Hepática/imunologia , Animais , Hepatectomia , Interleucina-6/metabolismo , Masculino , Camundongos , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismoRESUMO
A new biomimetic nanoreactor design, MaBiDz, is presented based on a copolymer brush in combination with superparamagnetic nanoparticles. This cellular nanoreactor features two species of magnetic particles, each functionalized with two components of a binary deoxyribozyme system. In the presence of a target mRNA analyte and a magnetic field, the nanoreactor is assembled to form a biocompartment enclosed by the polymeric brush that enables catalytic function of the binary deoxyribozyme with enhanced kinetics. MaBiDz was demonstrated here as a cellular sensor for rapid detection and imaging of a target mRNA biomarker for metastatic breast cancer, and its function shows potential to be expanded as a biomimetic organelle that can downregulate the activity of a target mRNA biomarker.
Assuntos
DNA Catalítico/química , Campos Magnéticos , Nanopartículas de Magnetita/química , Biomarcadores Tumorais/análise , Humanos , Células MCF-7 , Proteínas Nucleares , Polímeros , RNA Mensageiro/análise , Proteína 1 Relacionada a TwistRESUMO
Lymphotoxin (LT) is a member of the tumor necrosis factor (TNF) superfamily of cytokines which serves multiple functions, including the control of lymphoid organ development and maintenance, as well as regulation of inflammation and autoimmunity. Although the role of LT in organogenesis and maintenance of lymphoid organs is well established, the contribution of LT pathway to homeostasis of lymphoid organs during the immune response to pathogens is less understood. In this review, we highlight recent advances on the role of LT pathway in antiviral immune responses. We discuss the role of LT signaling in lymphoid organ integrity, type I IFN production and regulation of protection and immunopathology during viral infections. We further discuss the potential of therapeutic targeting LT pathway for controlling immunopathology and antiviral protection.
Assuntos
Antivirais/imunologia , Tecido Linfoide/fisiologia , Linfotoxina-alfa/imunologia , Viroses/imunologia , Animais , Autoimunidade , Homeostase/imunologia , Humanos , Inflamação , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Tecido Linfoide/imunologia , Receptor beta de Linfotoxina/imunologia , Linfotoxina-alfa/efeitos dos fármacos , Linfotoxina-alfa/genética , Camundongos , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/fisiologia , Viroses/tratamento farmacológico , Viroses/fisiopatologiaRESUMO
Splenomegaly is a well-known phenomenon typically associated with inflammation. However, the underlying cause of this phenotype has not been well characterized. Furthermore, the splenomegaly phenotype seen in lymphotoxin (LT) signaling-deficient mice is characterized by increased numbers of splenocytes and splenic neutrophils. Splenomegaly, as well as the related phenotype of increased lymphocyte counts in non-lymphoid tissues, is thought to result from the absence of secondary lymphoid tissues in LT-deficient mice. We now present evidence that mice deficient in LTα1ß2 or LTßR develop splenomegaly and increased numbers of lymphocytes in non-lymphoid tissues in a microbiota-dependent manner. Antibiotic administration to LTα1ß2- or LTßR-deficient mice reduces splenomegaly. Furthermore, re-derived germ-free Ltbr-/- mice do not exhibit splenomegaly or increased inflammation in non-lymphoid tissues compared to specific pathogen-free Ltbr-/- mice. By using various LTß- and LTßR-conditional knockout mice, we demonstrate that retinoic acid-related orphan receptor γT-positive type 3 innate lymphoid cells provide the required active LT signaling to prevent the development of splenomegaly. Thus, this study demonstrates the importance of LT-mediated immune responses for the prevention of splenomegaly and systemic inflammation induced by microbiota.
Assuntos
Imunidade Inata , Linfócitos/imunologia , Heterotrímero de Linfotoxina alfa1 e beta2/imunologia , Receptor beta de Linfotoxina/imunologia , Microbiota/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Animais , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Linfócitos/patologia , Heterotrímero de Linfotoxina alfa1 e beta2/genética , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Knockout , Receptores de Antígenos de Linfócitos T gama-delta/genéticaRESUMO
T and B cell compartmentalization is a hallmark of secondary lymphoid organs and is maintained by chemokine-expressing stromal cells. How this stromal cell network initially develops and differentiates into two distinct subsets is poorly known, especially for the splenic white pulp (WP). Here, we show that perivascular fibroblast precursors are triggered by LTα1ß2 signals to expand, express CCL19/21, and then differentiate into two functionally distinct fibroblast subsets responsible for B and T cell clustering and WP compartmentalization. Failure to express or sense CCL19 leads to impaired T zone development, while lack of B cells or LTα1ß2 leads to an earlier and stronger impairment in WP development. We therefore propose that WP development proceeds in multiple steps, with LTα1ß2+ B cells acting as major inducer cells driving the expansion and gradual differentiation of perivascular fibroblasts into T and B zone organizer cells.
Assuntos
Diferenciação Celular/fisiologia , Fibroblastos/metabolismo , Fibroblastos/fisiologia , Animais , Quimiocina CCL19/metabolismo , Quimiocina CXCL13/metabolismo , Quimiocinas CXC/metabolismo , Linfotoxina-alfa/metabolismo , Camundongos , Baço/citologia , Baço/metabolismoRESUMO
During αßT cell development, the thymus medulla represents an essential microenvironment for T cell tolerance. This functional specialization is attributed to its typical organized topology consisting of a branching structure that contains medullary thymic epithelial cell (mTEC) networks to support negative selection and Foxp3+ T-regulatory cell (T-reg) development. Here, by performing TEC-specific deletion of the thymus medulla regulator lymphotoxin ß receptor (LTßR), we show that thymic tolerance mechanisms operate independently of LTßR-mediated mTEC development and organization. Consistent with this, mTECs continue to express Fezf2 and Aire, regulators of intrathymic self-antigens, and support T-reg development despite loss of LTßR-mediated medulla organogenesis. Moreover, we demonstrate that LTßR controls thymic tolerance by regulating the frequency and makeup of intrathymic dendritic cells (DCs) required for effective thymocyte negative selection. In all, our study demonstrates that thymus medulla specialization for thymic tolerance segregates from medulla organogenesis and instead involves LTßR-mediated regulation of the thymic DC pool.
Assuntos
Tolerância Central/imunologia , Células Epiteliais/imunologia , Receptor beta de Linfotoxina/imunologia , Timo/imunologia , Animais , Autoantígenos/imunologia , Tolerância Central/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Proteínas de Ligação a DNA/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Células Epiteliais/metabolismo , Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Receptor beta de Linfotoxina/genética , Receptor beta de Linfotoxina/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia Confocal , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/imunologia , Proteínas do Tecido Nervoso/metabolismo , Organogênese/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timo/embriologia , Timo/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismo , Proteína AIRERESUMO
Detection of specific mRNA in living cells has attracted significant attention in the past decade. Probes that can be easily delivered into cells and activated at the desired time can contribute to understanding translation, trafficking and degradation of mRNA. Here we report a new strategy termed magnetic field-activated binary deoxyribozyme (MaBiDZ) sensor that enables both efficient delivery and temporal control of mRNA sensing by magnetic field. MaBiDZ uses two species of magnetic beads conjugated with different components of a multicomponent deoxyribozyme (DZ) sensor. The DZ sensor is activated only in the presence of a specific target mRNA and when a magnetic field is applied. Here we demonstrate that MaBiDZ sensor can be internalized in live MCF-7 breast cancer cells and activated by a magnetic field to fluorescently report the presence of specific mRNA, which are cancer biomarkers.