RESUMO
Gastro-intestinal helminth infections trigger the release of interleukin-33 (IL-33), which induces type-2 helper T cells (Th2 cells) at the site of infection to produce IL-13, thereby contributing to host resistance in a T cell receptor (TCR)-independent manner. Here, we show that, as a prerequisite for IL-33-induced IL-13 secretion, Th2 cells required the expression of the epidermal growth factor receptor (EGFR) and of its ligand, amphiregulin, for the formation of a signaling complex between T1/ST2 (the IL-33R) and EGFR. This shared signaling complex allowed IL-33 to induce the EGFR-mediated activation of the MAP-kinase signaling pathway and consequently the expression of IL-13. Lack of EGFR expression on T cells abrogated IL-13 expression in infected tissues and impaired host resistance. EGFR expression on Th2 cells was TCR-signaling dependent, and therefore, our data reveal a mechanism by which antigen presentation controls the innate effector function of Th2 cells at the site of inflammation.
Assuntos
Receptores ErbB/imunologia , Interleucina-13/imunologia , Interleucina-33/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Células Th2/imunologia , Anfirregulina/imunologia , Anfirregulina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Receptores ErbB/genética , Receptores ErbB/metabolismo , Expressão Gênica/genética , Expressão Gênica/imunologia , Perfilação da Expressão Gênica/métodos , Células HEK293 , Humanos , Interleucina-13/genética , Interleucina-13/metabolismo , Interleucina-33/genética , Interleucina-33/metabolismo , Sistema de Sinalização das MAP Quinases/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Nematospiroides dubius/imunologia , Nematospiroides dubius/fisiologia , Nocardia/imunologia , Nocardia/fisiologia , Nocardiose/imunologia , Nocardiose/metabolismo , Nocardiose/microbiologia , Receptores de Antígenos de Linfócitos T/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologia , Células Th2/metabolismoRESUMO
The transcription factor retinoic acid-related orphan receptor α (RORα) is important in regulating several physiological functions, such as cellular development, circadian rhythm, metabolism, and immunity. In two in vivo animal models of type 2 lung inflammation, Nippostrongylus brasiliensis infection and house dust mite (HDM) sensitization, we show a role for Rora in Th2 cellular development during pulmonary inflammation. N. brasiliensis infection and HDM challenge induced an increase in frequency of Rora-expressing GATA3+CD4 T cells in the lung. Using staggerer mice, which have a ubiquitous deletion of functional RORα, we generated bone marrow chimera mice, and we observed a delayed worm expulsion and reduced frequency in the expansion of Th2 cells and innate lymphoid type 2 cells (ILC2s) in the lungs after N. brasiliensis infection. ILC2-deficient mouse (Rorafl/flIl7raCre) also had delayed worm expulsion with associated reduced frequency of Th2 cells and ILC2s in the lungs after N. brasiliensis infection. To further define the role for Rora-expressing Th2 cells, we used a CD4-specific Rora-deficient mouse (Rorafl/flCD4Cre), with significantly reduced frequency of lung Th2 cells, but not ILC2, after N. brasiliensis infection and HDM challenge. Interestingly, despite the reduction in pulmonary Th2 cells in Rorafl/flCD4Cre mice, this did not impact the expulsion of N. brasiliensis after primary and secondary infection, or the generation of lung inflammation after HDM challenge. This study demonstrates a role for RORα in Th2 cellular development during pulmonary inflammation that could be relevant to the range of inflammatory diseases in which RORα is implicated.
Assuntos
Imunidade Inata , Pneumonia , Camundongos , Animais , Células Th2 , Receptor alfa de Ácido Retinoico , Linfócitos T CD4-Positivos , TretinoínaRESUMO
Reducing the pool of HIV-1 reservoirs in patients is a must to achieve functional cure. The most prominent HIV-1 cell reservoirs are resting CD4 + T cells and brain derived microglial cells. Infected microglial cells are believed to be the source of peripheral tissues reseedings and the emergence of drug resistance. Clearing infected cells from the brain is therefore crucial. However, many characteristics of microglial cells and the central nervous system make extremely difficult their eradication from brain reservoirs. Current methods, such as the "shock and kill", the "block and lock" and gene editing strategies cannot override these difficulties. Therefore, new strategies have to be designed when considering the elimination of brain reservoirs. We set up an original gene suicide strategy using latently infected microglial cells as model cells. In this paper we provide proof of concept of this strategy.
Assuntos
Encéfalo/virologia , Genes Transgênicos Suicidas , Infecções por HIV , HIV-1 , Latência Viral , Linfócitos T CD4-Positivos/virologia , Células Cultivadas , Edição de Genes , Humanos , Microglia/virologiaRESUMO
BACKGROUND: Atopic dermatitis (AD) is associated with a dysregulation of the skin barrier and may predispose to the development of secondary allergic conditions, such as asthma. Tmem79ma/ma mice harbor a mutation in the gene encoding Transmembrane Protein 79 (or Mattrin), which has previously been associated with AD. As a result of the Tmem79 gene mutation, these mice have a defective skin barrier and develop spontaneous skin inflammation. In this study, Tmem79ma/ma mice were assessed for the underlying immunological response in the development of spontaneous skin and lung inflammation. METHODS: Development of spontaneous skin and lung inflammation in Tmem79ma/ma mice was analyzed. We further investigated susceptibility to cutaneous Staphylococcus aureus infection. Tmem79ma/ma were crossed to IL-17A-deficient mice to address the contribution of IL-17A to spontaneous skin and lung disease. RESULTS: Tmem79ma/ma mice developed IL-17A-dependent spontaneous AD-like inflammation and were refractory to S aureus infection. Mutant mice progressed to airway inflammation subsequent to the occurrence of dermatitis. The progression from skin to lung disease is dependent on adaptive immunity and is facilitated by cutaneous expansion of Th17 and TCRγδ T cells. CONCLUSION: Mice lacking Tmem79/Mattrin expression have a defective skin barrier. In adulthood, these mice develop dermatitis with secondary progression to lung inflammation. The development of skin and lung inflammation is IL-17A-dependent and mediated by TCRγδ T cells.
Assuntos
Dermatite Atópica , Interleucina-17 , Pneumonia , Animais , Dermatite Atópica/genética , Modelos Animais de Doenças , Interleucina-17/genética , Proteínas de Membrana/genética , Camundongos , Pneumonia/genética , PeleRESUMO
Infection with parasite helminths induces potent modulation of the immune system of the host. Epidemiological and animal studies have shown that helminth infections can suppress or exacerbate unrelated autoimmune, allergic, and other inflammatory disorders. There is growing evidence that helminth infection-mediated suppression of bystander inflammatory responses is influenced by alterations in the intestinal microbiome modulating metabolic and immune functions of the infected host. We analyzed the fecal microbiota of mice infected with adult male Schistosoma mansoni worms, which are less susceptible to experimental colitis, and male- and female-worm-infected mice, which are highly sensitive to colitis. While both groups of infected mice developed a disrupted microbiota, there were marked alterations in mice with male and female worm infections. Antibiotic-treated recipients that were cohoused with both types of S. mansoni worm-infected mice acquired a colitogenic microbiome, leading to increased susceptibility to experimental colitis. Following anthelmintic treatment to remove worms from worm-only-infected mice, the mice developed exacerbated colitis. This study provides evidence that adult male S. mansoni worm infection modulates the host's immune system and suppresses bystander colitis while limiting dysbiosis of the host's intestinal microbiome during infection.
Assuntos
Colite/prevenção & controle , Microbioma Gastrointestinal , Esquistossomose mansoni/imunologia , Animais , Suscetibilidade a Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Esquistossomose mansoni/microbiologiaRESUMO
BACKGROUND: Atopic dermatitis (AD) is one of the most common skin diseases with a multifactorial etiology. Mutations leading to loss of skin barrier function are associated with the development of AD with group 2 innate lymphoid cells (ILC2) promoting acute skin inflammation. Filaggrin-mutant (Flgft/ft ) mice develop spontaneous skin inflammation accompanied by an increase in skin ILC2 numbers, IL-1ß production, and other cytokines recapitulating human AD. Here, we investigated the role of ILC2, effector cytokines, inflammasome activation, and mast cell function on the development of chronic AD-like inflammation in mice. METHODS: Mice with a frameshift mutation in the filaggrin gene develop spontaneous dermatitis. Flgft/ft mice were crossed to cell- or cytokine-deficient mouse strains, or bred under germ-free conditions. Skin inflammation was scored, and microbiome composition was analyzed. Skin protein expression was measured by multiplex immunoassay. Infiltrating cells were analyzed by flow cytometry. RESULTS: Wild-type and Flgft/ft mice significantly differ in their microbiome composition. Furthermore, mutant mice do not develop skin inflammation under germ-free conditions. ILC2 deficiency did not ameliorate chronic dermatitis in Flgft/ft mice, which was also independent of IL-4, IL-5, IL-9, IL-13, IL-17A, and IL-22. Inflammation was independent of NLRP3 inflammasome activation but required IL-1ß and IL-1R1-signaling. Mechanistically, IL-1ß promoted hyperactivation of IL-1R1-expressing mast cells. Treatment with anti-IL-1ß-antibody alleviated dermatitis exacerbation, while antibiotic intervention ameliorated dermatitis in neonatal mice but not in adults with established inflammation. CONCLUSIONS: In summary, we identified a critical role for the microbiome and IL-1ß mediating chronic inflammation in mice with an impaired skin barrier.
Assuntos
Dermatite Atópica/imunologia , Dermatite Atópica/metabolismo , Imunidade Inata , Interleucina-1beta/metabolismo , Linfócitos/imunologia , Linfócitos/metabolismo , Animais , Biópsia , Citocinas/metabolismo , Dermatite Atópica/patologia , Modelos Animais de Doenças , Proteínas Filagrinas , Inflamassomos/metabolismo , Linfócitos/patologia , Mastócitos/imunologia , Mastócitos/metabolismo , Camundongos , Camundongos Transgênicos , Microbiota , Fenótipo , Transdução de Sinais , Pele/imunologia , Pele/metabolismo , Pele/patologiaRESUMO
Basophils are associated with T helper 2 (Th2) cell-polarized immune responses such as allergic disorders or helminth infections. To directly address the role of basophils for type 2 immunity, we generated transgenic mice with constitutive and selective deletion of basophils. Differentiation and accumulation of Th2 cells, induction of eosinophilia, and increase in serum IgE or IgG1 induced by allergens or by infection with the helminth Nippostrongylus brasiliensis appeared to be basophil independent. Further, basophils were not required for passive IgE- or IgG1-mediated systemic anaphylaxis. However, basophils were essential for IgE-meditated chronic allergic dermatitis and for protection against secondary infection with N. brasiliensis. These results demonstrate that basophils play an important role for protective immunity against helminths and orchestrate chronic allergic inflammation, whereas primary Th2 cell responses can operate efficiently in the absence of this cell type.
Assuntos
Basófilos/fisiologia , Dermatite Atópica/imunologia , Nippostrongylus/imunologia , Animais , Asma/etiologia , Diferenciação Celular , Doença Crônica , Células Dendríticas/fisiologia , Imunidade Humoral , Imunoglobulina E/sangue , Memória Imunológica , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ovalbumina/imunologia , Papaína/farmacologia , Células Th2/citologiaRESUMO
Atopic dermatitis (AD) is a common inflammatory skin disease affecting up to 20% of children and 3% of adults worldwide and is associated with dysregulation of the skin barrier. Although type 2 responses are implicated in AD, emerging evidence indicates a potential role for the IL-17A signaling axis in AD pathogenesis. In this study we show that in the filaggrin mutant mouse model of spontaneous AD, IL-17RA deficiency (Il17ra-/- ) resulted in severe exacerbation of skin inflammation. Interestingly, Il17ra-/- mice without the filaggrin mutation also developed spontaneous progressive skin inflammation with eosinophilia, as well as increased levels of thymic stromal lymphopoietin (TSLP) and IL-5 in the skin. Il17ra-/- mice have a defective skin barrier with altered filaggrin expression. The barrier dysregulation and spontaneous skin inflammation in Il17ra-/- mice was dependent on TSLP, but not the other alarmins IL-25 and IL-33. The associated skin inflammation was mediated by IL-5-expressing pathogenic effector Th2 cells and was independent of TCRγδ T cells and IL-22. An absence of IL-17RA in nonhematopoietic cells, but not in the hematopoietic cells, was required for the development of spontaneous skin inflammation. Skin microbiome dysbiosis developed in the absence of IL-17RA, with antibiotic intervention resulting in significant amelioration of skin inflammation and reductions in skin-infiltrating pathogenic effector Th2 cells and TSLP. This study describes a previously unappreciated protective role for IL-17RA signaling in regulation of the skin barrier and maintenance of skin immune homeostasis.
Assuntos
Dermatite Atópica/imunologia , Receptores de Interleucina-17/imunologia , Receptores de Interleucina-17/metabolismo , Pele/crescimento & desenvolvimento , Pele/patologia , Animais , Citocinas/imunologia , Dermatite Atópica/patologia , Modelos Animais de Doenças , Disbiose , Eosinofilia/imunologia , Proteínas Filagrinas , Regulação da Expressão Gênica , Homeostase , Interleucina-33/imunologia , Interleucina-5/genética , Interleucina-5/imunologia , Interleucinas/genética , Interleucinas/imunologia , Proteínas de Filamentos Intermediários/deficiência , Proteínas de Filamentos Intermediários/genética , Camundongos , Microbiota , Mutação , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Receptores de Interleucina-17/deficiência , Receptores de Interleucina-17/genética , Transdução de Sinais , Pele/imunologia , Pele/microbiologia , Células Th2/imunologia , Linfopoietina do Estroma do Timo , Interleucina 22RESUMO
IgE-mediated activation of mast cells and basophils contributes to protective immunity against helminths but also causes allergic responses. The development and persistence of IgE responses are poorly understood, which is in part due to the low number of IgE-producing cells. Here, we used next generation sequencing to uncover a striking overlap between the IgE and IgG1 repertoires in helminth-infected or OVA/alum-immunized wild-type BALB/c mice. The memory IgE response after secondary infection induced a strong increase of IgE+ plasma cells in spleen and lymph nodes. In contrast, germinal center B cells did not increase during secondary infection. Unexpectedly, the memory IgE response was lost in mice where the extracellular part of IgG1 had been replaced with IgE sequences. Adoptive transfer studies revealed that IgG1+ B cells were required and sufficient to constitute the memory IgE response in recipient mice. T cell-derived IL-4/IL-13 was required for the memory IgE response but not for expansion of B cells from memory mice. Together, our results reveal a close relationship between the IgE and IgG1 repertoires in vivo and demonstrate that the memory IgE response is mainly conserved at the level of memory IgG1+ B cells. Therefore, targeting the generation and survival of allergen-specific IgG1+ B cells could lead to development of new therapeutic strategies to treat chronic allergic disorders.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Imunoglobulina E/metabolismo , Imunoglobulina G/metabolismo , Memória Imunológica , Interleucina-13/metabolismo , Interleucina-4/metabolismo , Plasmócitos/metabolismo , Imunidade Adaptativa , Transferência Adotiva , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/parasitologia , Linfócitos T CD4-Positivos/transplante , Proliferação de Células , Células Cultivadas , Switching de Imunoglobulina , Imunoglobulina E/química , Imunoglobulina E/genética , Imunoglobulina G/química , Interleucina-13/genética , Interleucina-4/genética , Linfonodos/imunologia , Linfonodos/metabolismo , Linfonodos/parasitologia , Linfonodos/patologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Nippostrongylus/imunologia , Plasmócitos/citologia , Plasmócitos/imunologia , Plasmócitos/parasitologia , Domínios e Motivos de Interação entre Proteínas , Baço/imunologia , Baço/metabolismo , Baço/parasitologia , Baço/patologia , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologia , Infecções por Strongylida/patologiaRESUMO
PURPOSE: To identify baseline optical coherence tomography morphologic characteristics predicting the visual response to anti-vascular endothelial growth factor therapy in diabetic macular edema. METHODS: Sixty-seven patients with diabetic macular edema completed a prospective, observational study (NCT01947881-CHARTRES). All patients received monthly intravitreal injections of Lucentis for 3 months followed by PRN treatment and underwent best-corrected visual acuity measurements and spectral domain optical coherence tomography at Baseline, Months 1, 2, 3, and 6. Visual treatment response was characterized as good (≥10 letters), moderate (5-10 letters), and poor (<5 or letters loss). Spectral domain optical coherence tomography images were graded before and after treatment by a certified Reading Center. RESULTS: One month after loading dose, 26 patients (38.80%) were identified as good responders, 19 (28.35%) as Moderate and 22 (32.83%) as poor responders. There were no significant best-corrected visual acuity and central retinal thickness differences at baseline (P = 0.176; P = 0.573, respectively). Ellipsoid zone disruption and disorganization of retinal inner layers were good predictors for treatment response, representing a significant risk for poor visual recovery to anti-vascular endothelial growth factor therapy (odds ratio = 10.96; P < 0.001 for ellipsoid zone disruption and odds ratio = 7.05; P = 0.034 for disorganization of retinal inner layers). CONCLUSION: Damage of ellipsoid zone, higher values of disorganization of retinal inner layers, and central retinal thickness decrease are good predictors of best-corrected visual acuity response to anti-vascular endothelial growth factor therapy.
Assuntos
Inibidores da Angiogênese/administração & dosagem , Retinopatia Diabética/tratamento farmacológico , Edema Macular/tratamento farmacológico , Ranibizumab/administração & dosagem , Retina/patologia , Acuidade Visual/fisiologia , Idoso , Retinopatia Diabética/patologia , Retinopatia Diabética/fisiopatologia , Feminino , Humanos , Injeções Intravítreas , Edema Macular/patologia , Edema Macular/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Retina/diagnóstico por imagem , Tomografia de Coerência Óptica , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidoresRESUMO
Interleukin (IL)-33, a member of the IL-1 family, was originally described in 2005 as a potent initiator of type 2 immunity found during allergic inflammation and parasitic infections. IL-33 has been shown to play important and potent roles bridging innate and adaptive immunity in the regulation of tissue homeostasis, injury, and repair. Recent discoveries have extended the range of functions for IL-33 beyond type 2 conditions and its role as an alarmin at barrier sites, with emerging central roles for IL-33 in T-cell regulation, obesity, viral and tumor immunity. Here, we review the recent advances on how IL-33 activity is regulated, its immunomodulatory properties on innate and adaptive cells, and the newly discovered roles of IL-33 in obesity, intestinal inflammation, and tumorigenesis.
Assuntos
Imunidade Adaptativa , Alarminas/imunologia , Enterite/imunologia , Interleucina-33/imunologia , Neoplasias/imunologia , Obesidade/imunologia , Células Th2/imunologia , Animais , Citocinas/imunologia , Humanos , Imunidade Inata , Neoplasias/etiologia , Obesidade/etiologiaRESUMO
Over 25% of the world's population are infected with helminth parasites, the majority of which colonise the gastrointestinal tract. However, no vaccine is yet available for human use, and mechanisms of protective immunity remain unclear. In the mouse model of Heligmosomoides polygyrus infection, vaccination with excretory-secretory (HES) antigens from adult parasites elicits sterilising immunity. Notably, three purified HES antigens (VAL-1, -2 and -3) are sufficient for effective vaccination. Protection is fully dependent upon specific IgG1 antibodies, but passive transfer confers only partial immunity to infection, indicating that cellular components are also required. Moreover, immune mice show greater cellular infiltration associated with trapping of larvae in the gut wall prior to their maturation. Intra-vital imaging of infected intestinal tissue revealed a four-fold increase in extravasation by LysM+GFP+ myeloid cells in vaccinated mice, and the massing of these cells around immature larvae. Mice deficient in FcRγ chain or C3 complement component remain fully immune, suggesting that in the presence of antibodies that directly neutralise parasite molecules, the myeloid compartment may attack larvae more quickly and effectively. Immunity to challenge infection was compromised in IL-4Rα- and IL-25-deficient mice, despite levels of specific antibody comparable to immune wild-type controls, while deficiencies in basophils, eosinophils or mast cells or CCR2-dependent inflammatory monocytes did not diminish immunity. Finally, we identify a suite of previously uncharacterised heat-labile vaccine antigens with homologs in human and veterinary parasites that together promote full immunity. Taken together, these data indicate that vaccine-induced immunity to intestinal helminths involves IgG1 antibodies directed against secreted proteins acting in concert with IL-25-dependent Type 2 myeloid effector populations.
Assuntos
Anticorpos Anti-Helmínticos/imunologia , Antígenos de Helmintos/imunologia , Imunoglobulina G/imunologia , Interleucina-4/imunologia , Interleucinas/imunologia , Nematospiroides dubius/imunologia , Infecções por Strongylida/imunologia , Vacinação , Animais , Anticorpos Anti-Helmínticos/genética , Humanos , Imunoglobulina G/genética , Interleucina-4/genética , Interleucinas/genética , Larva/imunologia , Camundongos , Camundongos Knockout , Infecções por Strongylida/genética , Infecções por Strongylida/prevenção & controleRESUMO
The persistence of latently infected cells in patients under combinatory antiretroviral therapy (cART) is a major hurdle to HIV-1 eradication. Strategies to purge these reservoirs are needed and activation of viral gene expression in latently infected cells is one promising strategy. Bromodomain and Extraterminal (BET) bromodomain inhibitors (BETi) are compounds able to reactivate latent proviruses in a positive transcription elongation factor b (P-TEFb)-dependent manner. In this study, we tested the reactivation potential of protein kinase C (PKC) agonists (prostratin, bryostatin-1 and ingenol-B), which are known to activate NF-κB signaling pathway as well as P-TEFb, used alone or in combination with P-TEFb-releasing agents (HMBA and BETi (JQ1, I-BET, I-BET151)). Using in vitro HIV-1 post-integration latency model cell lines of T-lymphoid and myeloid lineages, we demonstrated that PKC agonists and P-TEFb-releasing agents alone acted as potent latency-reversing agents (LRAs) and that their combinations led to synergistic activation of HIV-1 expression at the viral mRNA and protein levels. Mechanistically, combined treatments led to higher activations of P-TEFb and NF-κB than the corresponding individual drug treatments. Importantly, we observed in ex vivo cultures of CD8+-depleted PBMCs from 35 cART-treated HIV-1+ aviremic patients that the percentage of reactivated cultures following combinatory bryostatin-1+JQ1 treatment was identical to the percentage observed with anti-CD3+anti-CD28 antibodies positive control stimulation. Remarkably, in ex vivo cultures of resting CD4+ T cells isolated from 15 HIV-1+ cART-treated aviremic patients, the combinations bryostatin-1+JQ1 and ingenol-B+JQ1 released infectious viruses to levels similar to that obtained with the positive control stimulation. The potent effects of these two combination treatments were already detected 24 hours post-stimulation. These results constitute the first demonstration of LRA combinations exhibiting such a potent effect and represent a proof-of-concept for the co-administration of two different types of LRAs as a potential strategy to reduce the size of the latent HIV-1 reservoirs.
Assuntos
Briostatinas/farmacologia , Linfócitos T CD4-Positivos/virologia , Regulação Viral da Expressão Gênica/efeitos dos fármacos , HIV-1/efeitos dos fármacos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Diterpenos/metabolismo , HIV-1/fisiologia , Humanos , Fator B de Elongação Transcricional Positiva/metabolismo , Ativação Viral/efeitos dos fármacos , Latência Viral/efeitos dos fármacosRESUMO
Eosinophils are associated with type 2 immune responses to allergens and helminths. They release various proinflammatory mediators and toxic proteins on activation and are therefore considered proinflammatory effector cells. Eosinophilia is promoted by the cytokines interleukin (IL)-3, IL-5, and granulocyte macrophage-colony-stimulating factor (GM-CSF) and can result from enhanced de novo production or reduced apoptosis. In this study, we show that only IL-5 induces differentiation of eosinophils from bone marrow precursors, whereas IL-5, GM-CSF, and to a lesser extent IL-3 promote survival of mature eosinophils. The receptors for these cytokines use the common ß chain, which serves as the main signaling unit linked to signal transducer and activator of transcription 5, p38 mitogen-activated protein kinase, and nuclear factor (NF)-κB pathways. Inhibition of NF-κB induced apoptosis of in vitro cultured eosinophils. Selective deletion of IκBα in vivo resulted in enhanced expression of Bcl-xL and reduced apoptosis during helminth infection. Retroviral overexpression of Bcl-xL promoted survival, whereas pharmacologic inhibition of Bcl-xL in murine or human eosinophils induced rapid apoptosis. These results suggest that therapeutic strategies targeting Bcl-xL in eosinophils could improve health conditions in allergic inflammatory diseases.
Assuntos
Apoptose/fisiologia , Eosinófilos/imunologia , Proteínas I-kappa B/imunologia , NF-kappa B/imunologia , Proteína bcl-X/imunologia , Animais , Western Blotting , Eosinófilos/metabolismo , Citometria de Fluxo , Helmintíase Animal/imunologia , Humanos , Proteínas I-kappa B/metabolismo , Camundongos , Camundongos Transgênicos , Inibidor de NF-kappaB alfa , NF-kappa B/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/fisiologia , Proteína bcl-X/metabolismoRESUMO
Basophils orchestrate protection against reinfections with gastrointestinal helminths and ticks, but the underlying mechanisms remain elusive. We investigated the role of Fc receptors on basophils, the antibody isotypes IgG1 and IgE, and basophil-derived IL-4/IL-13 during challenge infections with Heligmosomoides polygyrus and Nippostrongylus brasiliensis. Using mixed bone marrow chimeras, we found that activating Fc receptors on basophils were required for protective immunity but not for regulation of basophil homeostasis. Furthermore, rapid worm expulsion was impaired in IgE-deficient but not in IgG1-deficient mice. Basophils promoted the recruitment of other effector cells into the small intestine and induced expression of the antihelminthic proteins resistin-like molecule ß and mucin 5ac. Selective deletion of IL-4/IL-13 in basophils resulted in impaired worm expulsion. Collectively, our results indicate that IgE-mediated activation of basophils and the release of basophil-derived IL-4/IL-13 are critical steps in protective immunity against helminths. Therefore, development of effective vaccines against helminths should consider boosting the IL-4/IgE/basophil axis of the immune system.
Assuntos
Basófilos/imunologia , Citocinas/imunologia , Trato Gastrointestinal/imunologia , Heligmosomatoidea/imunologia , Imunoglobulina E/imunologia , Infecções por Strongylida/imunologia , Animais , Basófilos/metabolismo , Basófilos/parasitologia , Western Blotting , Citocinas/metabolismo , Citometria de Fluxo , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/parasitologia , Heligmosomatoidea/fisiologia , Interações Hospedeiro-Parasita/imunologia , Imunoglobulina E/genética , Imunoglobulina E/metabolismo , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-13/metabolismo , Interleucina-4/genética , Interleucina-4/imunologia , Interleucina-4/metabolismo , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Intestino Delgado/parasitologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Nematospiroides dubius/imunologia , Nematospiroides dubius/fisiologia , Nippostrongylus/imunologia , Nippostrongylus/fisiologia , Receptores Fc/genética , Receptores Fc/imunologia , Receptores Fc/metabolismo , Infecções por Strongylida/metabolismo , Infecções por Strongylida/parasitologia , Células Th2/imunologia , Células Th2/metabolismoRESUMO
Disease conditions associated with pulmonary fibrosis are progressive and have a poor long-term prognosis with irreversible changes in airway architecture leading to marked morbidity and mortalities. Using murine models we demonstrate a role for interleukin (IL)-25 in the generation of pulmonary fibrosis. Mechanistically, we identify IL-13 release from type 2 innate lymphoid cells (ILC2) as sufficient to drive collagen deposition in the lungs of challenged mice and suggest this as a potential mechanism through which IL-25 is acting. Additionally, we demonstrate that in human idiopathic pulmonary fibrosis there is increased pulmonary expression of IL-25 and also observe a population ILC2 in the lungs of idiopathic pulmonary fibrosis patients. Collectively, we present an innate mechanism for the generation of pulmonary fibrosis, via IL-25 and ILC2, that occurs independently of T-cell-mediated antigen-specific immune responses. These results suggest the potential of therapeutically targeting IL-25 and ILC2 for the treatment of human fibrotic diseases.
Assuntos
Regulação da Expressão Gênica , Interleucina-17/metabolismo , Interleucinas/metabolismo , Linfócitos/citologia , Fibrose Pulmonar/metabolismo , Idoso , Animais , Moléculas de Adesão Celular/metabolismo , Colágeno/química , Colágeno/metabolismo , Feminino , Humanos , Fibrose Pulmonar Idiopática/patologia , Imunidade Inata , Inflamação , Interleucina-13/metabolismo , Fígado/parasitologia , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Fibrose Pulmonar/patologia , Schistosoma mansoniRESUMO
Schistosomiasis is a severe and chronic disease caused by the parasitic trematode Schistosoma mansoni after deposition of eggs in the liver and intestines. The immune response to S. mansoni eggs is characterized by increased Th2 cells, eosinophilia, and high serum IgE levels. Granulomas are formed around the eggs to protect the organs against tissue damage caused by toxic products that are secreted from the eggs. Egg-derived components have further been shown to activate the IgE-mediated release of IL-4 and IL-13 from basophils, suggesting that basophils could be involved in protection against a fatal course of infection. Using T cell-specific IL-4/IL-13-deficient mice and basophil-deficient Mcpt8Cre mice, we determined the contribution of Th2 cells and basophils for protective immunity against S. mansoni egg-induced pathology during the patent stage of infection. Our results demonstrate that T cell-derived IL-4/IL-13 was essential for granuloma formation, IgE production, basophilia, differentiation of alternatively activated macrophages, and protection against fatal infection. Although basophils were recruited into liver granulomas, they appeared to be dispensable as a source of IL-4/IL-13 both for differentiation of Th2 cells and for prevention of weight loss and mortality.
Assuntos
Basófilos/imunologia , Interleucina-13/imunologia , Interleucina-4/imunologia , Schistosoma mansoni/imunologia , Esquistossomose mansoni/imunologia , Células Th2/imunologia , Animais , Basófilos/patologia , Granuloma/genética , Granuloma/imunologia , Granuloma/parasitologia , Granuloma/patologia , Imunoglobulina E/genética , Imunoglobulina E/imunologia , Interleucina-13/genética , Interleucina-4/genética , Fígado/imunologia , Fígado/parasitologia , Fígado/patologia , Ativação de Macrófagos/genética , Macrófagos/imunologia , Macrófagos/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Esquistossomose mansoni/genética , Células Th2/patologiaRESUMO
Active positive transcription elongation factor b (P-TEFb) is essential for cellular and human immunodeficiency virus type 1 (HIV-1) transcription elongation. CTIP2 represses P-TEFb activity in a complex containing 7SK RNA and HEXIM1. Recently, the inactive 7SK/P-TEFb small nuclear RNP (snRNP) has been detected at the HIV-1 core promoter as well as at the promoters of cellular genes, but a recruiting mechanism still remains unknown to date. Here we show global synergy between CTIP2 and the 7SK-binding chromatin master-regulator HMGA1 in terms of P-TEFb-dependent endogenous and HIV-1 gene expression regulation. While CTIP2 and HMGA1 concordingly repress the expression of cellular 7SK-dependent P-TEFb targets, the simultaneous knock-down of CTIP2 and HMGA1 also results in a boost in Tat-dependent and independent HIV-1 promoter activity. Chromatin immunoprecipitation experiments reveal a significant loss of CTIP2/7SK/P-TEFb snRNP recruitment to cellular gene promoters and the HIV-1 promoter on HMGA1 knock-down. Our findings not only provide insights into a recruiting mechanism for the inactive 7SK/P-TEFb snRNP, but may also contribute to a better understanding of viral latency.
Assuntos
HIV-1/genética , Proteína HMGA1a/metabolismo , Fator B de Elongação Transcricional Positiva/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Linhagem Celular , Regulação da Expressão Gênica , HumanosRESUMO
The positive transcription elongation factor b (P-TEFb) is involved in physiological and pathological events including inflammation, cancer, AIDS, and cardiac hypertrophy. The balance between its active and inactive form is tightly controlled to ensure cellular integrity. We report that the transcriptional repressor CTIP2 is a major modulator of P-TEFb activity. CTIP2 copurifies and interacts with an inactive P-TEFb complex containing the 7SK snRNA and HEXIM1. CTIP2 associates directly with HEXIM1 and, via the loop 2 of the 7SK snRNA, with P-TEFb. In this nucleoprotein complex, CTIP2 significantly represses the Cdk9 kinase activity of P-TEFb. Accordingly, we show that CTIP2 inhibits large sets of P-TEFb- and 7SK snRNA-sensitive genes. In hearts of hypertrophic cardiomyopathic mice, CTIP2 controls P-TEFb-sensitive pathways involved in the establishment of this pathology. Overexpression of the ß-myosin heavy chain protein contributes to the pathological cardiac wall thickening. The inactive P-TEFb complex associates with CTIP2 at the MYH7 gene promoter to repress its activity. Taken together, our results strongly suggest that CTIP2 controls P-TEFb function in physiological and pathological conditions.