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1.
PLoS Pathog ; 16(9): e1008901, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32997722

RESUMO

The immune system of a host functions critically in shaping the composition of the microbiota, and some microbes are involved in regulating host endocrine system and development. However, whether the immune system acts on endocrine and development by shaping the composition of the microbiota remains unclear, and few molecular players or microbes involved in this process have been identified. In the current study, we found that RNA interference of a C-type lectin (HaCTL3) in the cotton bollworm Helicoverpa armigera suppresses ecdysone and juvenile hormone signaling, thus reducing larval body size and delaying pupation. Depletion of HaCTL3 also results in an increased abundance of Enterocuccus mundtii in the hemolymph, which may escape from the gut. Furthermore, HaCTL3 and its controlled antimicrobial peptides (attacin, lebocin, and gloverin) are involved in the clearance of E. mundtii from the hemolymph via phagocytosis or direct bactericidal activity. Injection of E. mundtii into larval hemocoel mimics HaCTL3-depleted phenotypes and suppresses ecdysone and juvenile hormone signaling. Taken together, we conclude that HaCTL3 maintains normal larval growth and development of H. armigera via suppressing the abundance of E. mundtii in the hemolymph. Our results provide the first evidence of an immune system acting on an endocrine system to modulate development via shaping the composition of microbiota in insect hemolymph. Thus, this study will deepen our understanding of the interaction between immunity and development.


Assuntos
Homeostase/fisiologia , Larva/crescimento & desenvolvimento , Larva/metabolismo , Lectinas Tipo C/metabolismo , Animais , Perfilação da Expressão Gênica/métodos , Hemolinfa/metabolismo , Imunidade Inata/genética , Proteínas de Insetos/metabolismo , Insetos/metabolismo , Fagocitose/fisiologia
2.
Sci Immunol ; 5(51)2020 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-32989174

RESUMO

Severe COVID-19 is characterized by excessive inflammation of the lower airways. The balance of protective versus pathological immune responses in COVID-19 is incompletely understood. Mucosa-associated invariant T (MAIT) cells are antimicrobial T cells that recognize bacterial metabolites, and can also function as innate-like sensors and mediators of antiviral responses. Here, we investigated the MAIT cell compartment in COVID-19 patients with moderate and severe disease, as well as in convalescence. We show profound and preferential decline in MAIT cells in the circulation of patients with active disease paired with strong activation. Furthermore, transcriptomic analyses indicated significant MAIT cell enrichment and pro-inflammatory IL-17A bias in the airways. Unsupervised analysis identified MAIT cell CD69high and CXCR3low immunotypes associated with poor clinical outcome. MAIT cell levels normalized in the convalescent phase, consistent with dynamic recruitment to the tissues and later release back into the circulation when disease is resolved. These findings indicate that MAIT cells are engaged in the immune response against SARS-CoV-2 and suggest their possible involvement in COVID-19 immunopathogenesis.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/patologia , Células T Invariáveis Associadas à Mucosa/imunologia , Pneumonia Viral/patologia , Adulto , Idoso , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Infecções por Coronavirus/imunologia , Feminino , Humanos , Imunidade Inata/imunologia , Inflamação/imunologia , Interleucina-17/metabolismo , Lectinas Tipo C/metabolismo , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia , Receptores CXCR3/metabolismo , Adulto Jovem
3.
Mol Immunol ; 126: 129-135, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32823237

RESUMO

Kalliklectin is a unique fish-specific lectin, whose sequence is similar to the heavy chain of mammalian plasma kallikrein and coagulation factor XI. In this study, we aimed to evaluate dynamic expression profiles of the lectin gene, during early developmental stages, in fugu, Takifugu rubripes. Reverse transcription-polymerase chain reaction (RT-PCR) showed that the kalliklectin gene was not expressed until 14 h post-fertilization (hpf), while the mRNA was detected after 30 hpf. In real-time quantitative PCR (qPCR), the gene was first expressed at 10.5 hpf; then, the expression level increased with a peak at 30 hpf and then gradually decreased. On the other hand, western blotting with specific antibody detected the lectin protein at all tested stages, including the unfertilized egg, which suggests that the lectin detected in the early stages was a maternal factor. Immunohistochemistry demonstrated that kalliklectin was localized at the basement membranes of the newly hatched larvae, while the lectin was widely detected in epidermal cells in larva at 5 dph. A 40-kDa lectin was partially purified from unfertilized eggs using mannose-affinity chromatography, and the lectin was determined as kalliklectin by liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (LC/Q-TOF-MS) analysis, which indicated that the lectin is functional in the eggs. The egg lectin can bind to Gram-positive bacterial pathogens of fish, such as Lactococcus garvieae and Streptococcus iniae. We conclude that fugu kalliklectin might be an important immunocomponent, transferred from mother to offspring.


Assuntos
Desenvolvimento Embrionário/imunologia , Proteínas de Peixes/metabolismo , Imunidade Materno-Adquirida , Lectinas Tipo C/metabolismo , Lectinas de Ligação a Manose/metabolismo , Receptores de Superfície Celular/metabolismo , Takifugu/crescimento & desenvolvimento , Animais , Embrião não Mamífero , Feminino , Proteínas de Peixes/imunologia , Perfilação da Expressão Gênica , Lactococcus/imunologia , Lectinas Tipo C/imunologia , Lectinas de Ligação a Manose/imunologia , Óvulo/imunologia , Óvulo/metabolismo , Receptores de Superfície Celular/imunologia , Streptococcus iniae/imunologia , Takifugu/imunologia , Takifugu/microbiologia
4.
Cornea ; 39(12): 1556-1562, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32826650

RESUMO

PURPOSE: To confirm the ocular tropism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by evaluating the expression of viral entry factors in human ocular tissues using immunohistochemistry. METHODS: Fresh donor corneas and primary explant cultures of corneal, limbal, and conjunctival epithelial cells were evaluated for the expression of viral entry factors. Using immunohistochemistry, the samples were tested for the expression of angiotension-converting enzyme 2 (ACE2), dendritic cell-specific intracellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN), DC-SIGN-related protein (DC-SIGNR), and transmembrane serine protease 2 (TMPRSS2). RESULTS: In total, 5 donor corneas were evaluated for the expression of viral entry factors. In all specimens, both ACE2 and TMPRSS2 were expressed throughout the surface epithelium (corneal, limbal, and conjunctival) and corneal endothelium. In corneal stromal cells, ACE2 was sporadically expressed, whereas TMPRSS2 was absent. DC-SIGN/DC-SIGNR expression varied between donor specimens. Four specimens expressed DC-SIGN/DC-SIGNR in a similar distribution to ACE2, but 1 specimen from a young donor showed no expression of DC-SIGN/DC-SIGNR. ACE2, TMPRSS2, and DC-SIGN/DC-SIGNR were all expressed in the cultured corneal, limbal, and conjunctival epithelial cells. CONCLUSIONS: Both corneal and conjunctival epithelia express ACE2, DC-SIGN/DC-SIGNR, and TMPRSS2, suggesting that the ocular surface is a potential route for the transmission of SARS-CoV-2. The risk of viral transmission with corneal transplantation cannot be ruled out, given the presence of ACE2 in corneal epithelium and endothelium. Cultured corneal, limbal, and conjunctival epithelial cells mimic the expression of viral entry factors in fresh donor tissue and may be useful for future in vitro SARS-CoV-2 infection studies.


Assuntos
Betacoronavirus/fisiologia , Moléculas de Adesão Celular/metabolismo , Túnica Conjuntiva/metabolismo , Epitélio Anterior/metabolismo , Lectinas Tipo C/metabolismo , Peptidil Dipeptidase A/metabolismo , Receptores de Superfície Celular/metabolismo , Serina Endopeptidases/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Cultivadas , Túnica Conjuntiva/citologia , Infecções por Coronavirus/imunologia , Células Epiteliais/metabolismo , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Limbo da Córnea/citologia , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia , Doadores de Tecidos , Tropismo Viral/fisiologia , Internalização do Vírus , Adulto Jovem
5.
Nat Commun ; 11(1): 4064, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792542

RESUMO

Regulation of the programming of tumour-associated macrophages (TAMs) controls tumour growth and anti-tumour immunity. We examined the role of FGF2 in that regulation. Tumours in mice genetically deficient in low-molecular weight FGF2 (FGF2LMW) regress dependent on T cells. Yet, TAMS not T cells express FGF receptors. Bone marrow derived-macrophages from Fgf2LMW-/- mice co-injected with cancer cells reduce tumour growth and express more inflammatory cytokines. FGF2 is induced in the tumour microenvironment following fractionated radiation in murine tumours consistent with clinical reports. Combination treatment of in vivo tumours with fractionated radiation and a blocking antibody to FGF2 prolongs tumour growth delay, increases long-term survival and leads to a higher iNOS+/CD206+ TAM ratio compared to irradiation alone. These studies show for the first time that FGF2 affects macrophage programming and is a critical regulator of immunity in the tumour microenvironment.


Assuntos
Fator 2 de Crescimento de Fibroblastos/metabolismo , Radioterapia/métodos , Animais , Linhagem Celular Tumoral , Fator 2 de Crescimento de Fibroblastos/genética , Células HT29 , Humanos , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/efeitos da radiação , Lectinas de Ligação a Manose/genética , Lectinas de Ligação a Manose/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Nus , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/efeitos da radiação , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Braz J Med Biol Res ; 53(9): e9693, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32696821

RESUMO

Ischemic heart disease (IHD) is one of the leading causes of death worldwide. C-type lectin domain family 3 member B (CLEC3B) is a C-type lectin superfamily member and is reported to promote tissue remodeling. The serum levels of CLEC3B are downregulated in patients with cardiovascular disease. However, the molecular mechanisms of CLEC3B in IHD is not well-characterized. Therefore, we overexpressed CLEC3B and silenced CLEC3B in H9c2 rat cardiomyocytes for the first time. We then constructed a model of IHD in vitro through culturing H9c2 cardiomyocytes in serum-free medium under oxygen-deficit conditions. Then, Cell Counting Kit-8 (CCK-8), flow cytometry, qRT-PCR, and western blot assays were performed to investigate cell viability, apoptosis, and expression levels of CLEC3B, phosphatidylinositol 3-kinase (PI3K), phosphorylated PI3K (p-PI3K), protein kinase B (Akt), phosphorylated Akt (p-Akt), and cleaved-caspase 3. We observed that the mRNA expression of CLEC3B was decreased in hypoxic H9c2 cardiomyocytes (P<0.05). Overexpression of CLEC3B increased cell viability (P<0.01), inhibited cell apoptosis (P<0.05), upregulated the levels of p-PI3K/PI3K and p-Akt/Akt (P<0.01 or P<0.05), and downregulated expression of cleaved-caspase 3 (P<0.001) in hypoxic H9c2 cardiomyocytes while silencing of CLEC3B caused the opposite results. Inhibition of the PI3K/Akt pathway reversed the protective effect of CLEC3B on hypoxic H9c2 cardiomyocytes. Our study demonstrated that CLEC3B alleviated the injury of hypoxic H9c2 cardiomyocytes via the PI3K/Akt pathway.


Assuntos
Apoptose/fisiologia , Lectinas Tipo C/metabolismo , Animais , Humanos , Hipóxia , Miócitos Cardíacos/fisiologia , Fosfatidilinositol 3-Quinase , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais
7.
Immunol Med ; 43(4): 161-170, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32649844

RESUMO

Cow milk is a nourishing food containing numerous essential nutrients. In Japan, the consumption of cow milk is thought to enhance resistance to exhaustion-related diseases. Although several nutrients in cow milk, such as lactoferrin, are thought to modulate immune cells, the mechanisms remain unclear. Recently, the immunoregulatory functions of food-derived microRNAs or exosomes have been reported. Therefore, we studied the effects of exosomes derived from cow milk (CM-Exs) on immune cells in the present study. We obtained blood samples from healthy adult donors with the approval of the ethics committee. Peripheral blood mononuclear cells (PBMCs) were stimulated with CM-Exs in the absence or presence of interleukin-2 (IL-2) and IL-12. Cell surface markers and intracellular cytokine production were analysed by flow cytometry. CM-Ex stimulation enhanced the expression of CD69 on NK cells. Although CM-Ex stimulation alone did not induce interferon-γ (IFN-γ) production by NK cells or γδT cells, simultaneous stimulation with CM-Ex, IL-2 and IL-12 significantly enhanced IFN-γ production. In conclusion, cow milk consumption alone may not activate immune cells; however, CM-Exs could enhance immune cells under inflammatory conditions.


Assuntos
Exossomos/imunologia , Exossomos/fisiologia , Células Matadoras Naturais/imunologia , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Leite/citologia , Linfócitos T/imunologia , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Células Cultivadas , Citocinas/metabolismo , Citometria de Fluxo , Humanos , Interferon gama/metabolismo , Interleucina-12/imunologia , Interleucina-2/imunologia , Células Matadoras Naturais/metabolismo , Lectinas Tipo C/metabolismo , Leucócitos Mononucleares/metabolismo , Linfócitos T/metabolismo
8.
Life Sci ; 258: 118085, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663578

RESUMO

BACKGROUND: An integral intestinal barrier is essential for intestinal homeostasis. Yet, as a side effect of cancer treatment, chemotherapeutic drugs have been reported to cause mucositis. In a recent study, we found that alginate oligosaccharides (AOS) prevent busulfan induced intestinal mucositis. However, it is not known if AOS improves small intestine epithelial cell integrity and migration, which are two essential processes for maintaining the mechanical barrier function of the small intestine. In the current investigation, we aimed to explore the effects of AOS on the integrity and migration of small intestine cells using swine intestinal epithelial IPEC-J2 cells. METHODS: Cell integrity was determined using the TEER assay. Cell migration capability was detected using a wound healing experiment. Small interfering RNA (siRNA) was used to inhibit mannose receptor (MR) expression. Western blotting and immunofluorescence staining were used to determine protein expression. RESULTS: Increasing levels of AOS improved cell integrity as measure by TEER. At the same time, AOS improved IPEC-J2 cell migration capacity as shown in the wound closure assay. It is interesting to note that AOS increased the expression of intestinal microvillus proteins and junction proteins to benefit cell integrity. MR siRNA blocked the action of AOS on cell integrity and cell migration and inhibited the expression of microvillus and cell junction proteins. CONCLUSION: We identified the underlying mechanisms by which AOS improved small intestinal mucositis. As a novel, natural food additive, AOS may be administered to prevent intestinal mucositis induced by chemotherapy or other issues.


Assuntos
Alginatos/farmacologia , Movimento Celular/efeitos dos fármacos , Intestino Delgado/citologia , Oligossacarídeos/farmacologia , Animais , Linhagem Celular , Lectinas Tipo C/metabolismo , Lectinas de Ligação a Manose/metabolismo , Proteínas dos Microfilamentos/metabolismo , Microvilosidades/efeitos dos fármacos , Microvilosidades/metabolismo , Miosinas/metabolismo , RNA Interferente Pequeno/metabolismo , Receptores de Superfície Celular/metabolismo , Suínos , Proteínas de Junções Íntimas/metabolismo , Cicatrização/efeitos dos fármacos
9.
Toxicon ; 185: 57-63, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32598989

RESUMO

C-type lectins (CTL) and CTL-like proteins (snaclecs) are important toxins found in snake venom which can disrupt hemostasis by binding platelet membrane glycoproteins. Traditional identification of these toxins usually relies on an "activity-directed fractionation" approach which is very arduous. Here, we report a new method for rapid screening of these proteins in snake venom. METHODS: A conserved and immunogenic peptide found in svCTLs (CTL and snaclecs) was identified by sequence alignment using DNAStar software. The peptide was de novo synthesized and conjugated to keyhole limpet hemocyanin (KLH). Rabbit antibodies were generated against the peptide by classical immunization. Deinagkistrodon acutus venom was separated by two-dimensional electrophoresis (2DE) followed by Western blot and CTLs immunodetected using the isolated polyclonal antibody. The same svCTL spots on a parallel 2DE gel were isolated and analyzed by MALDI-TOF-MS. RESULTS: A highly conserved peptide with the sequence "KTWDDAEKFCTEQ" was identified as a common epitope in svCTLs. The polyclonal antibody against the 13aa-peptide was successfully prepared and purified. Its usefulness to detect svCTLs in D. acutus venom was tested by 2DE-WB and we determined that it positively identified all known D. acutus venom CTLs. CONCLUSIONS: Immunodetection with antibodies against KTWDDAEKFCTEQ is an efficient strategy to identify novel svCTLs in the context of a complex proteome.


Assuntos
Lectinas Tipo C/metabolismo , Proteoma/metabolismo , Venenos de Serpentes/metabolismo , Sequência de Aminoácidos , Animais , Western Blotting , Espectrometria de Massas , Proteômica , Coelhos , Alinhamento de Sequência , Venenos de Serpentes/toxicidade
10.
PLoS Negl Trop Dis ; 14(6): e0008386, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32542003

RESUMO

Chromoblastomycosis (CBM) is a chronic worldwide subcutaneous mycosis, caused by several dimorphic, pigmented dematiaceous fungi. It is difficult to treat patients with the disease, mainly because of its recalcitrant nature. The correct activation of host immune response is critical to avoid fungal persistence in the tissue and disease chronification. CD4+ T cells are crucial for the development of protective immunity to F. pedrosoi infection. Here, we investigated T helper cell response dynamics during experimental CBM. Following footpad injection with F. pedrosoi hyphae and conidia, T cells were skewed towards a Th17 and Th1 phenotype. The Th17 population was the main Th cell subset found in the infected area during the early stages of experimental murine CBM, followed by Th1 predominance in the later stages, coinciding with the remission phase of the disease in this experimental model. Depletion of CD25+ cells, which leads to a reduction of Treg cells in the draining lymph node, resulted in decline in fungal burden after 14 days of infection. However, fungal cells were not cleared in the later stages of the disease, prolonging CBM clinical features in those animals. IL-17A and IFN-γ neutralization hindered fungal cell elimination in the course of the disease. Similarly, in dectin-2 KO animals, Th17 contraction in the course of experimental CBM was accompanied by fungal burden decrease in the first 14 days of infection, although it did not affect disease resolution. In this study, we gained insight into T helper subsets' dynamics following footpad injections of F. pedrosoi propagules and uncovered their contribution to disease resolution. The Th17 population proved to be important in eliminating fungal cells in the early stages of infection. The Th1 population, in turn, closely assisted by Treg cells, proved to be relevant not only in the elimination of fungal cells at the beginning of infection but also essential for their complete elimination in later stages of the disease in a mouse experimental model of CBM.


Assuntos
Ascomicetos/imunologia , Cromoblastomicose/imunologia , Lectinas Tipo C/metabolismo , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th17/imunologia , Animais , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Cromoblastomicose/microbiologia , Cromoblastomicose/patologia , Modelos Animais de Doenças , Humanos , Hifas , Interferon gama/metabolismo , Interleucina-17/metabolismo , Lectinas Tipo C/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Esporos Fúngicos
11.
Am J Pathol ; 190(9): 1833-1842, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32473917

RESUMO

Cholestatic liver injury leads to liver dysfunction. The available evidence suggests that platelets can either promote or reduce liver injury and fibrosis. This study focused on the functions of the C-type lectin-like receptor 2 (CLEC-2), a new special platelet receptor that binds with podoplanin-activating platelets. The role of CLEC-2 and podoplanin in cholestatic liver injury was investigated. Mice were injected intraperitoneally with weekly doses of anti-CLEC-2 antibody (2A2B10) to achieve effective CLEC-2 inhibition in their platelets. Next, left and middle hepatic bile duct ligation (BDL) procedures were performed, and mice were euthanized 1 week later (2A2B10-BDL group). In addition, mice were prepared for control groups, and relevant histological and laboratory variables were compared among these groups. The inhibition of CLEC-2 resulted in increasing hepatocellular necrosis, hepatic inflammation, and liver fibrosis. In addition, podoplanin was strongly expressed in hepatic sinusoidal endothelial cells in BDL-treated mice. Moreover, in 2A2B10-BDL mice, total plasma bile acid levels were significantly increased. In summary, podoplanin is expressed on hepatic sinusoidal endothelial cells upon BDL. Platelets bind with podoplanin via CLEC-2 and become activated. As a result, the total bile acid pool is decreased. Therefore, the CLEC-2-podoplanin interaction promotes liver protection and inhibits liver fibrosis after cholestatic liver injury.


Assuntos
Plaquetas/metabolismo , Colestase/metabolismo , Lectinas Tipo C/metabolismo , Glicoproteínas de Membrana/metabolismo , Animais , Colestase/patologia , Células Endoteliais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ativação Plaquetária/fisiologia
12.
Proc Natl Acad Sci U S A ; 117(23): 12980-12990, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32461368

RESUMO

The aryl hydrocarbon receptor (AhR) represents an environmental sensor regulating immune responses. In the skin, AhR is expressed in several cell types, including keratinocytes, epidermal Langerhans cells (LC), and dermal dendritic cells (DC). The mechanisms how AhR activates or inhibits cutaneous immune responses remain controversial, owing to differences in the cell-specific functions of AhR and the different activating ligands. Therefore, we sought to investigate the role of AhR in LC and langerin+ and negative DC in the skin. To this aim, we generated Langerin-specific and CD11c-specific knockout (-/-) mice lacking AhR, respectively, in LC and Langerin+ dermal DC and in all CD11c+ cells. These were then tested in an epicutaneous protein (ovalbumin, Ova) sensitization model. Immunofluorescence microscopy and flow cytometry revealed that Langerin-AhR-/- but not CD11c-AhR-/- mice harbored a decreased number of LC with fewer and stunted dendrites in the epidermis as well as a decreased number of LC in skin-draining lymph nodes (LN). Moreover, in the absence of AhR, we detected an enhanced T helper type-2 (Th2) [increased interleukin 5 (IL-5) and interleukin 13 (IL-13)] and T regulatory type-1 (Tr1) (IL-10) response when LN cells were challenged with Ova in vitro, though the number of regulatory T cells (Treg) in the LN remained comparable. Langerin-AhR-/- mice also exhibited increased blood levels of Ova-specific immunoglobulin E (IgE). In conclusion, deletion of AhR in langerin-expressing cells diminishes the number and activation of LC, while enhancing Th2 and Tr1 responses upon epicutaneous protein sensitization.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Células de Langerhans/imunologia , Receptores de Hidrocarboneto Arílico/metabolismo , Linfócitos T Reguladores/imunologia , Células Th2/imunologia , Administração Cutânea , Animais , Antígenos de Superfície/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Epiderme/imunologia , Epiderme/metabolismo , Técnicas de Inativação de Genes , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Células de Langerhans/metabolismo , Lectinas Tipo C/metabolismo , Lectinas de Ligação a Manose/metabolismo , Camundongos , Camundongos Transgênicos , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Receptores de Hidrocarboneto Arílico/genética , Linfócitos T Reguladores/metabolismo , Células Th2/metabolismo
13.
Curr Top Microbiol Immunol ; 425: 17-28, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32385534

RESUMO

Dihydroxynaphthalene melanin (DHN-melanin) is an integral component of the conidial cell wall surface, which has a central role in the pathogenicity of the major human airborne fungal pathogen Aspergillus fumigatus. Although the biosynthetic pathway for A. fumigatus DHN-melanin production has been well characterized, the molecular interactions of DHN-melanin with the immune system have been incompletely understood. Recent studies demonstrated that apart from concealing immunostimulatory cell wall polysaccharides, calcium sequestration by DHN-melanin inhibits essential host effector pathways regulating phagosome biogenesis and prevents A. fumigatus conidia killing by phagocytes. From the host perspective, DHN-melanin is specifically recognized by a C-type lectin receptor (MelLeC) present in murine endothelia and in human myeloid cells. Furthermore, DHN-melanin activates platelets and facilitates opsonophagocytosis by macrophages via binding to soluble pattern recognition receptors. Dissecting the dynamics of DHN-melanin organization on the fungal cell wall and the molecular interplay with the immune system will lead to a better understanding of A. fumigatus pathophysiology.


Assuntos
Aspergillus fumigatus , Melaninas , Naftóis , Animais , Aspergilose/imunologia , Aspergilose/metabolismo , Aspergilose/microbiologia , Aspergillus fumigatus/citologia , Aspergillus fumigatus/imunologia , Aspergillus fumigatus/metabolismo , Aspergillus fumigatus/patogenicidade , Parede Celular/química , Parede Celular/metabolismo , Humanos , Lectinas Tipo C/metabolismo , Melaninas/metabolismo , Naftóis/metabolismo , Receptores Mitogênicos/metabolismo
14.
Curr Top Microbiol Immunol ; 429: 103-115, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32300915

RESUMO

Mycobacteria have unique lipids on their cell walls, and the structures and physiological activities of these lipid components have been the subject of many studies. Although the host receptors for mycobacterial lipid have long been elusive, in recent years C-type lectin receptors (CLRs) have been reported to recognize these components. The dendritic cell immunoactivating receptor (DCAR), a CLR member, is encoded by Clec4b1. DCAR, which was identified in 2003, is reported to be associated with the immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptor protein, the Fc receptor γ chain (FcRγ). However, its physiological ligand and biological function were unknown. We recently identified DCAR as an activating receptor for mycobacteria. DCAR recognizes acylated phosphatidyl-inositol mannosides (PIMs) in mycobacteria to promote Th1 responses during mycobacterial infection. This review summarizes recent discoveries about the ligands and immunological roles of DCAR.


Assuntos
Mycobacterium , Proteínas Adaptadoras de Transdução de Sinal , Células Dendríticas/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Mycobacterium/metabolismo , Receptores Fc/metabolismo
15.
Nat Commun ; 11(1): 1913, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32312989

RESUMO

The TAGAP gene locus has been linked to several infectious diseases or autoimmune diseases, including candidemia and multiple sclerosis. While previous studies have described a role of TAGAP in T cells, much less is known about its function in other cell types. Here we report that TAGAP is required for Dectin-induced anti-fungal signaling and proinflammatory cytokine production in myeloid cells. Following stimulation with Dectin ligands, TAGAP is phosphorylated by EPHB2 at tyrosine 310, which bridges proximal Dectin-induced EPHB2 activity to downstream CARD9-mediated signaling pathways. During Candida albicans infection, mice lacking TAGAP mount defective immune responses, impaired Th17 cell differentiation, and higher fungal burden. Similarly, in experimental autoimmune encephalomyelitis model of multiple sclerosis, TAGAP deficient mice develop significantly attenuated disease. In summary, we report that TAGAP plays an important role in linking Dectin-induced signaling to the promotion of effective T helper cell immune responses, during both anti-fungal host defense and autoimmunity.


Assuntos
Antifúngicos/imunologia , Candidíase/imunologia , Diferenciação Celular , Proteínas Ativadoras de GTPase/química , Proteínas Ativadoras de GTPase/metabolismo , Receptor EphB2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células Th17/metabolismo , Animais , Antifúngicos/farmacologia , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/microbiologia , Feminino , Proteínas Ativadoras de GTPase/genética , Humanos , Lectinas Tipo C/metabolismo , Masculino , Camundongos Knockout , Esclerose Múltipla/complicações , Esclerose Múltipla/imunologia , Fosforilação , Receptor EphB2/imunologia , Receptores Imunológicos , Receptores de Reconhecimento de Padrão/metabolismo , Células Th17/imunologia
16.
Am J Respir Crit Care Med ; 201(10): 1209-1217, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32197050

RESUMO

Rationale: Interstitial macrophages (IMs) and airspace macrophages (AMs) play critical roles in lung homeostasis and host defense, and are central to the pathogenesis of a number of lung diseases. However, the absolute numbers of macrophages and the precise anatomic locations they occupy in the healthy human lung have not been quantified.Objectives: To determine the precise number and anatomic location of human pulmonary macrophages in nondiseased lungs and to quantify how this is altered in chronic cigarette smokers.Methods: Whole right upper lobes from 12 human donors without pulmonary disease (6 smokers and 6 nonsmokers) were evaluated using design-based stereology. CD206 (cluster of differentiation 206)-positive/CD43+ AMs and CD206+/CD43- IMs were counted in five distinct anatomical locations using the optical disector probe.Measurements and Main Results: An average of 2.1 × 109 IMs and 1.4 × 109 AMs were estimated per right upper lobe. Of the AMs, 95% were contained in diffusing airspaces and 5% in airways. Of the IMs, 78% were located within the alveolar septa, 14% around small vessels, and 7% around the airways. The local density of IMs was greater in the alveolar septa than in the connective tissue surrounding the airways or vessels. The total number and density of IMs was 36% to 56% greater in the lungs of cigarette smokers versus nonsmokers.Conclusions: The precise locations occupied by pulmonary macrophages were defined in nondiseased human lungs from smokers and nonsmokers. IM density was greatest in the alveolar septa. Lungs from chronic smokers had increased IM numbers and overall density, supporting a role for IMs in smoking-related disease.


Assuntos
Fumar Cigarros/patologia , Pulmão/patologia , Macrófagos Alveolares/patologia , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Contagem de Células , Feminino , Humanos , Imuno-Histoquímica , Lectinas Tipo C/metabolismo , Leucossialina/metabolismo , Pulmão/citologia , Pulmão/metabolismo , Macrófagos Alveolares/metabolismo , Masculino , Lectinas de Ligação a Manose/metabolismo , Pessoa de Meia-Idade , Dispositivos Ópticos , Receptores de Superfície Celular/metabolismo , Doadores de Tecidos
17.
Toxicon ; 178: 92-99, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32135198

RESUMO

Opossums in the clade Didelphini are well known to be resistant to snake venom due to endogenous circulating inhibitors which target metalloproteinases and phospholipases. However, the mechanisms through which these opossums cope with a variety of other damaging venom proteins are unknown. A protein involved in blood clotting (von Willebrand Factor) has been found to have undergone rapid adaptive evolution in venom-resistant opossums. This protein is a known target for a subset of snake venom C-type lectins (CTLs), which bind it and then induce it to bind platelets, causing hemostatic disruption. Several amino acid changes in vWF unique to these opossums could explain their resistance; however, experimental evidence that these changes disrupt venom CTL binding was lacking. We used platelet aggregation assays to quantify resistance to a venom-induced platelet response in two species of venom-resistant opossums (Didelphis virginiana, Didelphis aurita), and one venom-sensitive opossum (Monodelphis domestica). We found that all three species have lost nearly all their aggregation response to the venom CTLs tested. Using washed platelet assays we showed that this loss of aggregation response is not due to inhibitors in the plasma, but rather to the failure of either vWF or platelets (or both) to respond to venom CTLs. These results demonstrate the potential adaptive function of a trait previously shown to be evolving under positive selection. Surprisingly, these findings also expand the list of potentially venom tolerant species to include Monodelphis domestica and suggest that an ecological relationship between opossums and vipers may be a broader driver of adaptive evolution across South American marsupials than previously thought.


Assuntos
Adaptação Fisiológica/fisiologia , Didelphis/fisiologia , Venenos de Serpentes/toxicidade , Fator de von Willebrand/metabolismo , Animais , Plaquetas/metabolismo , Lectinas Tipo C/metabolismo , Metaloproteases/metabolismo , Agregação Plaquetária , Venenos de Serpentes/química , Venenos de Serpentes/metabolismo , América do Sul
18.
J Neuroinflammation ; 17(1): 48, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019570

RESUMO

BACKGROUND: Ischemic stroke is a main cause of mortality. Blood-brain barrier (BBB) breakdown appears to play a critical role in inflammation in patients with ischemic stroke and acceleration of brain injury. The BBB has a protective function and is composed of endothelial cells, pericytes, and astrocytes. In ischemic stroke treatments, regulation of vascular endothelial growth factor (VEGF)-A and vascular endothelial growth factor receptor (VEGFR)-2 is a crucial target despite adverse effects. Our previous study found that loss of C-type lectin family 14 member A (CLEC14A) activated VEGF-A/VEGFR-2 signaling in developmental and tumoral angiogenesis. Here, we evaluate the effects of BBB impairment caused by CLEC14A deficiency in ischemia-reperfusion injury. METHODS: In vitro fluorescein isothiocyanate (FITC)-dextran permeability, transendothelial electrical resistance (TEER) assay, and immunostaining were used to evaluate endothelial integrity. BBB permeability was assessed using Evans blue dye and FITC-dextran injection in Clec14a-/- (CLEC14A-KO) mice and wild-type mice. Middle cerebral artery occlusion surgery and behavioral assessments were performed to evaluate the neurologic damage. The change of tight junctional proteins, adhesion molecules, pro-inflammatory cytokines, and microglial were confirmed by immunofluorescence staining, Western blotting, and quantitative reverse transcription polymerase chain reaction of brain samples. RESULTS: In endothelial cells, knockdown of CLEC14A increased FITC-dextran permeability and decreased transendothelial electrical resistance; the severity of this effect increased with VEGF treatment. Immunofluorescence staining revealed that tight junctional proteins were attenuated in the CLEC14A knockdown endothelial cells. Consistent with the in vitro results, CLEC14A-KO mice that were injected with Evans blue dye had cerebral vascular leakage at postnatal day 8; wild-type mice had no leakage. We used a middle cerebral artery occlusion model and found that CLEC14A-KO mice had severe infarcted brain and neurological deficits with upregulated VEGFR-2 expression. FITC-dextran leakage was present in CLEC14A-KO mice after ischemia-reperfusion, and the numbers of tight junctional molecules were significantly decreased. Loss of CLEC14A increased the pro-inflammatory response through adhesion molecule expression, and glial cells were activated. CONCLUSIONS: These results suggest that activation of VEGFR-2 in CLEC14A-KO mice aggravates ischemic stroke by exacerbating cerebral vascular leakage and increasing neuronal inflammation after ischemia-reperfusion injury.


Assuntos
Barreira Hematoencefálica/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Lectinas Tipo C/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Traumatismo por Reperfusão/metabolismo , Animais , Barreira Hematoencefálica/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Infarto da Artéria Cerebral Média/genética , Infarto da Artéria Cerebral Média/patologia , Inflamação/metabolismo , Inflamação/patologia , Lectinas Tipo C/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Neurônios/patologia , Permeabilidade , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia
19.
J Ethnopharmacol ; 252: 112637, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32004631

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Acute kidney injury (AKI) is a common disease in hospitalized patients, especially in critically ill patients. It is characterised with high morbidity and mortality, and is also an important cause of chronic kidney disease and chronic renal failure. Astragalus propinquus Schischkin and Panax notoginseng (A&P) compound, a famous traditional Chinese medicine, consists of Astragalus propinquus Schischkin, Panax notoginseng, Angelica sinensis, Achyranthes bidentata, and Ecklonia kurome, has been widely used for the treatment of various kidney diseases in the southwest of China. However, the effects of A&P on treatment of AKI and its underlying mechanism are needed to be uncovered. AIM OF THE STUDY: Recent researches reported that Mincle (Macrophage-inducible C-type lectin) plays a key role in renal injury of AKI by regulating the expression and secretion of inflammatory cytokines on macrophage through modulating NF-κB signaling pathway. Here, we aimed to investigate the renoprotective effect of A&P on AKI and whether by inhibiting Mincle. MATERIALS AND METHODS: We established a lipopolysaccharide (LPS)-induced Bone Marrow-Derived Macrophage (BMDM) inflammatory cell model and a cisplatin-induced mouse AKI model in vitro and in vivo. Renal histopathology staining was performed to observe kidney morphology. The expression and secretion of inflammatory cytokines were detected by real-time PCR and Enzyme-linked immunosorbent assay. Western blotting was used to detect the protein levels and Flow cytometry performed to detect polarization of macrophage. RESULTS: The results showed that A&P significantly reduced the mRNA expression of IL-1ß, IL-6, TNFα and MCP-1 in LPS-stimulated BMDM cells, and secretion of IL-1ß and IL-6 in supernatant. The same results were found in Cisplatin-induced AKI kidney and serum after treatment with A&P. The data also showed that A&P strongly reduced the mRNA and protein levels of Mincle in vitro and vivo, and also inhibited the activation of Syk and NF-κB. Notably, A&P down-regulated the M1 macrophage marker iNOS, which may relate to the inhibition of Mincle. Interestingly, both overexpression of Mincle by transfection of pcDNA3.1-Mincle plasmid and administration of TDB (a ligand of Mincle) can significantly abolished the A&P-inhibited inflammation in BMDM, suggesting Mincle pathway play a key role in macrophage inflammation in AKI. CONCLUSION: Our findings indicated that A&P protected kidney from inhibiting inflammation through down-regulating of Mincle pathway in macrophage in AKI. It provides a potential medicine compound for the treatment of AKI.


Assuntos
Lesão Renal Aguda/tratamento farmacológico , Anti-Inflamatórios/uso terapêutico , Lectinas Tipo C/antagonistas & inibidores , Proteínas de Membrana/antagonistas & inibidores , Substâncias Protetoras/uso terapêutico , Lesão Renal Aguda/induzido quimicamente , Lesão Renal Aguda/metabolismo , Lesão Renal Aguda/patologia , Animais , Anti-Inflamatórios/farmacologia , Antineoplásicos , Células Cultivadas , Cisplatino , Citocinas/genética , Rim/efeitos dos fármacos , Rim/patologia , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Lipopolissacarídeos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Substâncias Protetoras/farmacologia , Transdução de Sinais/efeitos dos fármacos , Quinase Syk/metabolismo
20.
Curr Top Microbiol Immunol ; 429: 1-18, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32060644

RESUMO

C-type lectin receptors (CLRs) are a family of transmembrane proteins having at least one C-type lectin-like domain (CTLD) on the cell surface and either a short intracellular signaling tail or a transmembrane domain that facilitates interaction with a second protein, often the Fc receptor common gamma chain (FcRγ), that mediates signaling. Many CLRs directly recognize microbial cell walls and influence innate immunity by activating inflammatory and antimicrobial responses in phagocytes. In this review, we examine the contributions of certain CLRs to activation and regulation of phagocytosis in cells such as macrophages, dendritic cells and neutrophils.


Assuntos
Lectinas Tipo C , Fagocitose , Imunidade Inata , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Neutrófilos , Transdução de Sinais
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