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1.
Cells ; 9(10)2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-33003471

RESUMO

COVID-19, caused by SARS-CoV-2 virus, emerged as a pandemic disease posing a severe threat to global health. To date, sporadic studies have demonstrated that innate immune mechanisms, specifically neutrophilia, NETosis, and neutrophil-associated cytokine responses, are involved in COVID-19 pathogenesis; however, our understanding of the exact nature of this aspect of host-pathogen interaction is limited. Here, we present a detailed dissection of the features and functional profiles of neutrophils, dendritic cells, and monocytes in COVID-19. We portray the crucial role of neutrophils as drivers of hyperinflammation associated with COVID-19 disease via the shift towards their immature forms, enhanced degranulation, cytokine production, and augmented interferon responses. We demonstrate the impaired functionality of COVID-19 dendritic cells and monocytes, particularly their low expression of maturation markers, increased PD-L1 levels, and their inability to upregulate phenotype upon stimulation. In summary, our work highlights important data that prompt further research, as therapeutic targeting of neutrophils and their associated products may hold the potential to reduce the severity of COVID-19.


Assuntos
Infecções por Coronavirus/sangue , Células Dendríticas/imunologia , Monócitos/imunologia , Neutrófilos/imunologia , Pneumonia Viral/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Células Cultivadas , Infecções por Coronavirus/imunologia , Citocinas/genética , Citocinas/metabolismo , Feminino , Humanos , Imunidade Inata , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia
2.
DNA Cell Biol ; 39(10): 1838-1849, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32876480

RESUMO

The breast cancer gene 1 (BRCA1) is a tumor suppressor, and mutations or epigenetic inactivation will increase the risk of breast cancer oncogenesis. The current research aimed to explore the relationship between BRCA1 expression, prognosis, and tumor immunity in hepatocellular carcinoma (HCC). In this study, BRCA1 expression was analyzed via multiple online databases and its association with clinical characteristics, prognosis and genetic alterations was identified using the original The Cancer Genome Atlas-liver hepatocellular carcinoma cohorts. DNA methylation sites and their prognostic values were analyzed using MethSurv. The correlations between BRCA1 and immune infiltration were investigated via Tumor Immune Estimation Resource. As results, BRCA1 was significantly upregulated in tumor tissues in multiple HCC cohorts. Besides, high BRCA1 expression was correlated with race, advanced T stage, clinical stage, poor tumor grade, MSI status, and worse prognosis. Notably, BRCA1 expression was positively correlated with infiltration levels of B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells. The current findings imply that BRCA1 is associated with prognosis and immune infiltration, laying foundations for in-depth research on the role of BRCA1 in HCC.


Assuntos
Proteína BRCA1/genética , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Proteína BRCA1/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/patologia , Movimento Celular , Metilação de DNA , Células Dendríticas/imunologia , Humanos , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/patologia , Linfócitos/imunologia , Macrófagos/imunologia
3.
Vaccine ; 38(42): 6487-6499, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32907757

RESUMO

The many carbohydrate chains on Covid-19 coronavirus SARS-CoV-2 and its S-protein form a glycan-shield that masks antigenic peptides and decreases uptake of inactivated virus or S-protein vaccines by APC. Studies on inactivated influenza virus and recombinant gp120 of HIV vaccines indicate that glycoengineering of glycan-shields to present α-gal epitopes (Galα1-3Galß1-4GlcNAc-R) enables harnessing of the natural anti-Gal antibody for amplifying vaccine efficacy, as evaluated in mice producing anti-Gal. The α-gal epitope is the ligand for the natural anti-Gal antibody which constitutes ~1% of immunoglobulins in humans. Upon administration of vaccines presenting α-gal epitopes, anti-Gal binds to these epitopes at the vaccination site and forms immune complexes with the vaccines. These immune complexes are targeted for extensive uptake by APC as a result of binding of the Fc portion of immunocomplexed anti-Gal to Fc receptors on APC. This anti-Gal mediated effective uptake of vaccines by APC results in 10-200-fold higher anti-viral immune response and in 8-fold higher survival rate following challenge with a lethal dose of live influenza virus, than same vaccines lacking α-gal epitopes. It is suggested that glycoengineering of carbohydrate chains on the glycan-shield of inactivated SARS-CoV-2 or on S-protein vaccines, for presenting α-gal epitopes, will have similar amplifying effects on vaccine efficacy. α-Gal epitope synthesis on coronavirus vaccines can be achieved with recombinant α1,3galactosyltransferase, replication of the virus in cells with high α1,3galactosyltransferase activity as a result of stable transfection of cells with several copies of the α1,3galactosyltransferase gene (GGTA1), or by transduction of host cells with replication defective adenovirus containing this gene. In addition, recombinant S-protein presenting multiple α-gal epitopes on the glycan-shield may be produced in glycoengineered yeast or bacteria expression systems containing the corresponding glycosyltransferases. Prospective Covid-19 vaccines presenting α-gal epitopes may provide better protection than vaccines lacking this epitope because of increased uptake by APC.


Assuntos
Antígenos Virais/genética , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Glicoproteína da Espícula de Coronavírus/genética , Trissacarídeos/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/biossíntese , Antígenos Virais/imunologia , Antígenos Virais/metabolismo , Betacoronavirus/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/virologia , Engenharia Genética , Proteína do Núcleo p24 do HIV/química , Proteína do Núcleo p24 do HIV/genética , Proteína do Núcleo p24 do HIV/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Humanos , Imunogenicidade da Vacina , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/virologia , Camundongos , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Trissacarídeos/química , Vacinas Virais/administração & dosagem , Vacinas Virais/biossíntese , Vacinas Virais/genética
4.
PLoS Pathog ; 16(9): e1008854, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32956405

RESUMO

Aspergillus fumigatus is an opportunistic fungal pathogen of immunocompromised patient populations. Mortality is thought to be context-specific and occurs via both enhanced fungal growth and immunopathogenesis. NLRX1 is a negative regulator of immune signaling and metabolic pathways implicated in host responses to microbes, cancers, and autoimmune diseases. Our study indicates loss of Nlrx1 results in enhanced fungal burden, pulmonary inflammation, immune cell recruitment, and mortality across immuno-suppressed and immuno-competent models of IPA using two clinically derived isolates (AF293, CEA10). We observed that the heightened mortality is due to enhanced recruitment of CD103+ dendritic cells (DCs) that produce elevated amounts of IL-4 resulting in a detrimental Th2-mediated immune response. Adoptive transfer of Nlrx1-/- CD103+ DCs in neutropenic NRG mice results in enhanced mortality that can be ablated using IL-4 neutralizing antibodies. In vitro analysis of CD103+ DCs indicates loss of Nlrx1 results in enhanced IL-4 production via elevated activation of the JNK/JunB pathways. Interestingly, loss of Nlrx1 also results in enhanced recruitment of monocytes and neutrophils. Chimeras of irradiated Nlrx1-/- mice reconstituted with wild type bone marrow have enhanced neutrophil recruitment and survival during models of IPA. This enhanced immune cell recruitment in the absence of Nlrx1 is mediated by excessive production of CXCL8/IL-8 family of chemokines and IL-6 via early and enhanced activation of P38 in response to A. fumigatus conidia as shown in BEAS-2B airway epithelial cells. In summary, our results point strongly towards the cell-specific and contextual function of Nlrx1 during invasive pulmonary aspergillosis and may lead to novel therapeutics to reduce Th2 responses by CD103+ DCs or heightened recruitment of neutrophils.


Assuntos
Aspergillus fumigatus/imunologia , Células Dendríticas/imunologia , Sistema de Sinalização das MAP Quinases/imunologia , Proteínas Mitocondriais/imunologia , Aspergilose Pulmonar/imunologia , Células Th2/imunologia , Animais , Linhagem Celular , Citocinas/genética , Citocinas/imunologia , MAP Quinase Quinase 4/genética , MAP Quinase Quinase 4/imunologia , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Proteínas Mitocondriais/genética , Neutrófilos/imunologia , Neutrófilos/patologia , Aspergilose Pulmonar/genética , Aspergilose Pulmonar/patologia , Células Th2/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/imunologia
5.
Nat Commun ; 11(1): 4835, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973173

RESUMO

Immune checkpoint blockade therapies have shown clinical promise in a variety of cancers, but how tumor-infiltrating T cells are activated remains unclear. In this study, we explore the functions of PD-L1 on dendritic cells (DCs), which highly express PD-L1. We observe that PD-L1 on DC plays a critical role in limiting T cell responses. Type 1 conventional DCs are essential for PD-L1 blockade and they upregulate PD-L1 upon antigen uptake. Upregulation of PD-L1 on DC is mediated by type II interferon. While DCs are the major antigen presenting cells for cross-presenting tumor antigens to T cells, subsequent PD-L1 upregulation protects them from killing by cytotoxic T lymphocytes, yet dampens the antitumor responses. Blocking PD-L1 in established tumors promotes re-activation of tumor-infiltrating T cells for tumor control. Our study identifies a critical and dynamic role of PD-L1 on DC, which needs to be harnessed for better invigoration of antitumor immune responses.


Assuntos
Antígeno B7-H1/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Ativação Linfocitária , Animais , Antígenos de Neoplasias/metabolismo , Antígeno B7-H1/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Células HEK293 , Humanos , Interferon gama/metabolismo , Linfócitos do Interstício Tumoral/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Linfócitos T Citotóxicos/imunologia , Microambiente Tumoral/imunologia , Regulação para Cima
6.
Cells ; 9(9)2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911691

RESUMO

The ongoing pandemic due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has so far infected about 2.42 × 107 (as at 27 August 2020) subjects with more than 820,000 deaths. It is the third zoonotic coronavirus-dependent outbreak in the last twenty years and represents a major infective threat for public health worldwide. A main aspect of the infection, in analogy to other viral infections, is the so-called "cytokine storm", an inappropriate molecular response to virus spread which plays major roles in tissue and organ damage. Immunological therapies, including vaccines and humanized monoclonal antibodies, have been proposed as major strategies for prevention and treatment of the disease. Accordingly, a detailed mechanistic knowledge of the molecular events with which the virus infects cells and induces an immunological response appears necessary. In this review, we will report details of the initial process of SARS-CoV-2 cellular entry with major emphasis on the maturation of the spike protein. Then, a particular focus will be devoted to describe the possible mechanisms by which dendritic cells, a major cellular component of innate and adaptive immune responses, may play a role in the spread of the virus in the human body and in the clinical evolution of the disease.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/virologia , Células Dendríticas/virologia , Pneumonia Viral/virologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Humanos , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/metabolismo , Piroptose , Sistema Renina-Angiotensina , Internalização do Vírus
7.
Anticancer Res ; 40(10): 5765-5776, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988904

RESUMO

BACKGROUND/AIM: We evaluated the safety, feasibility, and preliminary efficacy of Wilms tumor gene 1 (WT1) peptide and Mucin 1 (MUC1)-pulsed dendritic cell (DC) (WT1/MUC1-DC) vaccination as an adjuvant immunotherapy for surgically resectable pancreatic ductal adenocarcinoma (PDA) patients. PATIENTS AND METHODS: Eligible patients were administered WT1/MUC1-DC vaccination at least seven times every 2 weeks with concomitant adjuvant chemotherapy after surgical resection of PDA. RESULTS: Ten patients were enrolled and no Grade 2 or higher toxicities were associated with DC vaccination. The estimated overall survival (OS) and relapse-free survival (RFS) at 3-years from the time of surgical resection were 77.8% and 35.0%, respectively. Immunohistochemical analysis suggested a possible relationship between induction of WT1-specific cytotoxic T lymphocyte after DC vaccination and higher infiltration of CD3/CD4/CD8 lymphocytes in tumor tissues. CONCLUSION: WT1/MUC1-DC vaccination in the adjuvant setting was safe and well-tolerated in PDA patients after tumor resection. A large-scale prospective study is warranted to evaluate the clinical benefit of this modality.


Assuntos
Adenocarcinoma/tratamento farmacológico , Carcinoma Ductal Pancreático/tratamento farmacológico , Mucina-1/genética , Proteínas WT1/genética , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Idoso , Vacinas Anticâncer/administração & dosagem , Vacinas Anticâncer/imunologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/cirurgia , Quimioterapia Adjuvante/métodos , Células Dendríticas/imunologia , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Intervalo Livre de Doença , Feminino , Humanos , Imunoterapia/métodos , Masculino , Pessoa de Meia-Idade , Mucina-1/uso terapêutico , Proteínas WT1/uso terapêutico
8.
PLoS One ; 15(8): e0236212, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797100

RESUMO

Although an impact of processing on immunogenicity of food proteins has clearly been demonstrated, the underlying mechanisms are still unclear. We applied 3 different processing methods: wet heating (60 °C) and low- or high-temperature (50 °C or 130 °C, respectively) dry-heating in absence or presence of reducing sugars, to ß-lactoglobulin (BLG), lysozyme and thyroglobulin, which represent dietary proteins with different pI or molecular weight. Uptake of the soluble fraction of the samples was tested in two types of, genetically homogeneous, antigen-presenting cells (macrophages and dendritic cells derived from THP-1 monocytes). This revealed a strong correlation between the uptake of the different protein samples by macrophages and dendritic cells, and confirmed the key role of hydrophobicity, over aggregation, in determining the uptake. Several uptake routes were shown to contribute to the uptake of BLG by macrophages. However, cytokine responses following exposure of macrophages to BLG samples were not related to the levels of uptake. Together, our results demonstrate that heat-treatment-induced increased hydrophobicity is the prime driving factor in uptake, but not in cytokine production, by THP-1 macrophages.


Assuntos
Citocinas/metabolismo , Células Dendríticas/imunologia , Proteínas na Dieta/imunologia , Macrófagos/imunologia , Receptores de Superfície Celular/metabolismo , Culinária , Células Dendríticas/metabolismo , Proteínas na Dieta/química , Proteínas na Dieta/metabolismo , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Macrófagos/metabolismo , Peso Molecular , Células THP-1
9.
Science ; 369(6508): 1210-1220, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32788292

RESUMO

Coronavirus disease 2019 (COVID-19) represents a global crisis, yet major knowledge gaps remain about human immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We analyzed immune responses in 76 COVID-19 patients and 69 healthy individuals from Hong Kong and Atlanta, Georgia, United States. In the peripheral blood mononuclear cells (PBMCs) of COVID-19 patients, we observed reduced expression of human leukocyte antigen class DR (HLA-DR) and proinflammatory cytokines by myeloid cells as well as impaired mammalian target of rapamycin (mTOR) signaling and interferon-α (IFN-α) production by plasmacytoid dendritic cells. By contrast, we detected enhanced plasma levels of inflammatory mediators-including EN-RAGE, TNFSF14, and oncostatin M-which correlated with disease severity and increased bacterial products in plasma. Single-cell transcriptomics revealed a lack of type I IFNs, reduced HLA-DR in the myeloid cells of patients with severe COVID-19, and transient expression of IFN-stimulated genes. This was consistent with bulk PBMC transcriptomics and transient, low IFN-α levels in plasma during infection. These results reveal mechanisms and potential therapeutic targets for COVID-19.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Citocinas/sangue , DNA Bacteriano/sangue , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Citometria de Fluxo , Antígenos HLA-DR/análise , Humanos , Imunidade , Imunidade Inata , Imunoglobulinas/sangue , Imunoglobulinas/imunologia , Mediadores da Inflamação/sangue , Interferon Tipo I/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/sangue , Masculino , Células Mieloides/imunologia , Células Mieloides/metabolismo , Pandemias , Transdução de Sinais , Análise de Célula Única , Biologia de Sistemas , Serina-Treonina Quinases TOR/metabolismo , Transcrição Genética , Transcriptoma
10.
Nat Commun ; 11(1): 4289, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855397

RESUMO

Older organs represent an untapped potential to close the gap between demand and supply in organ transplantation but are associated with age-specific responses to injury and increased immunogenicity, thereby aggravating transplant outcomes. Here we show that cell-free mitochondrial DNA (cf-mt-DNA) released by senescent cells accumulates with aging and augments immunogenicity. Ischemia reperfusion injury induces a systemic increase of cf-mt-DNA that promotes dendritic cell-mediated, age-specific inflammatory responses. Comparable events are observed clinically, with the levels of cf-mt-DNA elevated in older deceased organ donors, and with the isolated cf-mt-DNA capable of activating human dendritic cells. In experimental models, treatment of old donor animals with senolytics clear senescent cells and diminish cf-mt-DNA release, thereby dampening age-specific immune responses and prolonging the survival of old cardiac allografts comparable to young donor organs. Collectively, we identify accumulating cf-mt-DNA as a key factor in inflamm-aging and present senolytics as a potential approach to improve transplant outcomes and availability.


Assuntos
DNA Mitocondrial/efeitos adversos , Dasatinibe/farmacologia , Inflamação/prevenção & controle , Transplante de Órgãos/métodos , Quercetina/farmacologia , Adulto , Envelhecimento/fisiologia , Animais , Diferenciação Celular , Ácidos Nucleicos Livres , Senescência Celular/efeitos dos fármacos , Senescência Celular/fisiologia , Citocinas/metabolismo , DNA Mitocondrial/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/fisiologia , Transplante de Coração/efeitos adversos , Transplante de Coração/métodos , Humanos , Inflamação/etiologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Pessoa de Meia-Idade , Transplante de Órgãos/efeitos adversos , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/imunologia , Doadores de Tecidos
11.
Science ; 369(6506): 993-999, 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-32820126

RESUMO

Stimulator of interferon genes (STING) links innate immunity to biological processes ranging from antitumor immunity to microbiome homeostasis. Mechanistic understanding of the anticancer potential for STING receptor activation is currently limited by metabolic instability of the natural cyclic dinucleotide (CDN) ligands. From a pathway-targeted cell-based screen, we identified a non-nucleotide, small-molecule STING agonist, termed SR-717, that demonstrates broad interspecies and interallelic specificity. A 1.8-angstrom cocrystal structure revealed that SR-717 functions as a direct cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) mimetic that induces the same "closed" conformation of STING. SR-717 displayed antitumor activity; promoted the activation of CD8+ T, natural killer, and dendritic cells in relevant tissues; and facilitated antigen cross-priming. SR-717 also induced the expression of clinically relevant targets, including programmed cell death 1 ligand 1 (PD-L1), in a STING-dependent manner.


Assuntos
Antineoplásicos/farmacologia , Materiais Biomiméticos/farmacologia , Proteínas de Membrana/metabolismo , Nucleotídeos Cíclicos/farmacologia , Animais , Antígeno B7-H1/metabolismo , Materiais Biomiméticos/química , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Cristalografia por Raios X , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Humanos , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Camundongos , Nucleotídeos Cíclicos/química , Conformação Proteica/efeitos dos fármacos
12.
Nat Med ; 26(10): 1623-1635, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32807934

RESUMO

Improved understanding and management of COVID-19, a potentially life-threatening disease, could greatly reduce the threat posed by its etiologic agent, SARS-CoV-2. Toward this end, we have identified a core peripheral blood immune signature across 63 hospital-treated patients with COVID-19 who were otherwise highly heterogeneous. The signature includes discrete changes in B and myelomonocytic cell composition, profoundly altered T cell phenotypes, selective cytokine/chemokine upregulation and SARS-CoV-2-specific antibodies. Some signature traits identify links with other settings of immunoprotection and immunopathology; others, including basophil and plasmacytoid dendritic cell depletion, correlate strongly with disease severity; while a third set of traits, including a triad of IP-10, interleukin-10 and interleukin-6, anticipate subsequent clinical progression. Hence, contingent upon independent validation in other COVID-19 cohorts, individual traits within this signature may collectively and individually guide treatment options; offer insights into COVID-19 pathogenesis; and aid early, risk-based patient stratification that is particularly beneficial in phasic diseases such as COVID-19.


Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Infecções por Coronavirus/imunologia , Citocinas/imunologia , Células Dendríticas/imunologia , Pneumonia Viral/imunologia , Linfócitos T/imunologia , Idoso , Subpopulações de Linfócitos B/imunologia , Basófilos/imunologia , Betacoronavirus , Estudos de Casos e Controles , Ciclo Celular , Quimiocina CXCL10/imunologia , Quimiocinas/imunologia , Estudos de Coortes , Infecções por Coronavirus/sangue , Progressão da Doença , Feminino , Citometria de Fluxo , Hospitalização , Humanos , Memória Imunológica , Imunofenotipagem , Interleucina-10/imunologia , Interleucina-6/imunologia , Contagem de Leucócitos , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/sangue , Prognóstico , Índice de Gravidade de Doença , Subpopulações de Linfócitos T/imunologia , Regulação para Cima
13.
Med Hypotheses ; 143: 110122, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32759007

RESUMO

A characteristic feature of COVID-19 disease is lymphopenia. Lymphopenia occurs early in the clinical course and is a predictor of disease severity and outcomes. The mechanism of lymphopenia in COVID-19 is uncertain. It has been variously attributed to the release of inflammatory cytokines including IL-6 and TNF-α; direct infection of the lymphocytes by the virus; and rapid sequestration of lymphocytes in the tissues. Additionally, we postulate that prostaglandin D2 (PGD2) is a key meditator of lymphopenia in COVID-19. First, SARS-CoV infection is known to stimulate the production of PGD2 in the airways, which inhibits the host dendritic cell response via the DP1 receptor signaling. Second, PGD2 is known to upregulate monocytic myeloid-derived suppressor cells (MDSC) via the DP2 receptor signaling in group 2 innate lymphoid cells (ILC2). We propose targeting PGD2/DP2 signaling using a receptor antagonist such as ramatroban as an immunotherapy for immune dysfunction and lymphopenia in COVID-19 disease.


Assuntos
Betacoronavirus , Infecções por Coronavirus/fisiopatologia , Linfopenia/fisiopatologia , Modelos Imunológicos , Terapia de Alvo Molecular , Pandemias , Pneumonia Viral/fisiopatologia , Prostaglandina D2/fisiologia , Sistema Respiratório/metabolismo , Adulto , Carbazóis/farmacologia , Carbazóis/uso terapêutico , Criança , Infecções por Coronavirus/complicações , Infecções por Coronavirus/imunologia , Células Dendríticas/imunologia , Humanos , Linfopenia/etiologia , Células Mieloides/imunologia , Pneumonia Viral/complicações , Pneumonia Viral/imunologia , Prostaglandina D2/biossíntese , Receptores Imunológicos/antagonistas & inibidores , Receptores Imunológicos/metabolismo , Receptores de Prostaglandina/antagonistas & inibidores , Receptores de Prostaglandina/metabolismo , Receptores de Prostaglandina/fisiologia , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico , Linfócitos T/imunologia , Tromboxano A2/antagonistas & inibidores
14.
Nature ; 585(7823): 96-101, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32814898

RESUMO

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative disorders that overlap in their clinical presentation, pathology and genetic origin. Autoimmune disorders are also overrepresented in both ALS and FTD, but this remains an unexplained epidemiologic observation1-3. Expansions of a hexanucleotide repeat (GGGGCC) in the C9orf72 gene are the most common cause of familial ALS and FTD (C9-ALS/FTD), and lead to both repeat-containing RNA and dipeptide accumulation, coupled with decreased C9orf72 protein expression in brain and peripheral blood cells4-6. Here we show in mice that loss of C9orf72 from myeloid cells alone is sufficient to recapitulate the age-dependent lymphoid hypertrophy and autoinflammation seen in animals with a complete knockout of C9orf72. Dendritic cells isolated from C9orf72-/- mice show marked early activation of the type I interferon response, and C9orf72-/- myeloid cells are selectively hyperresponsive to activators of the stimulator of interferon genes (STING) protein-a key regulator of the innate immune response to cytosolic DNA. Degradation of STING through the autolysosomal pathway is diminished in C9orf72-/- myeloid cells, and blocking STING suppresses hyperactive type I interferon responses in C9orf72-/- immune cells as well as splenomegaly and inflammation in C9orf72-/- mice. Moreover, mice lacking one or both copies of C9orf72 are more susceptible to experimental autoimmune encephalitis, mirroring the susceptibility to autoimmune diseases seen in people with C9-ALS/FTD. Finally, blood-derived macrophages, whole blood and brain tissue from patients with C9-ALS/FTD all show an elevated type I interferon signature compared with samples from people with sporadic ALS/FTD; this increased interferon response can be suppressed with a STING inhibitor. Collectively, our results suggest that patients with C9-ALS/FTD have an altered immunophenotype because their reduced levels of C9orf72 cannot suppress the inflammation mediated by the induction of type I interferons by STING.


Assuntos
Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Inflamação/metabolismo , Inflamação/prevenção & controle , Proteínas de Membrana/metabolismo , Células Mieloides/metabolismo , Envelhecimento/imunologia , Esclerose Amiotrófica Lateral/genética , Animais , Proteína C9orf72/deficiência , Células Dendríticas/citologia , Células Dendríticas/imunologia , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Feminino , Humanos , Inflamação/genética , Inflamação/imunologia , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Células Mieloides/imunologia , Neoplasias/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia
15.
J Exp Med ; 217(12)2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-32820330

RESUMO

Type I interferons (IFN-I) are a major antiviral defense and are critical for the activation of the adaptive immune system. However, early viral clearance by IFN-I could limit antigen availability, which could in turn impinge upon the priming of the adaptive immune system. In this study, we hypothesized that transient IFN-I blockade could increase antigen presentation after acute viral infection. To test this hypothesis, we infected mice with viruses coadministered with a single dose of IFN-I receptor-blocking antibody to induce a short-term blockade of the IFN-I pathway. This resulted in a transient "spike" in antigen levels, followed by rapid antigen clearance. Interestingly, short-term IFN-I blockade after coronavirus, flavivirus, rhabdovirus, or arenavirus infection induced a long-lasting enhancement of immunological memory that conferred improved protection upon subsequent reinfections. Short-term IFN-I blockade also improved the efficacy of viral vaccines. These findings demonstrate a novel mechanism by which IFN-I regulate immunological memory and provide insights for rational vaccine design.


Assuntos
Imunogenicidade da Vacina/imunologia , Interferon Tipo I/antagonistas & inibidores , Interferon-alfa/imunologia , Receptor de Interferon alfa e beta/imunologia , Vacinas Virais/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Animais , Anticorpos Bloqueadores/imunologia , Anticorpos Bloqueadores/farmacologia , Anticorpos Antivirais/imunologia , Apresentação do Antígeno/imunologia , Linfócitos T CD8-Positivos/metabolismo , Células Dendríticas/imunologia , Modelos Animais de Doenças , Expressão Gênica/imunologia , Células HEK293 , Humanos , Memória Imunológica , Interferon-alfa/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor de Interferon alfa e beta/genética , Transfecção , Infecção por Zika virus/virologia
16.
PLoS One ; 15(8): e0237034, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745117

RESUMO

Production of IFN-γ is a key innate immune mechanism that limits replication of intracellular bacteria such as Francisella tularensis (Ft) until adaptive immune responses develop. Previously, we demonstrated that the host cell types responsible for IFN-γ production in response to murine Francisella infection include not only natural killer (NK) and T cells, but also a variety of myeloid cells. However, production of IFN-γ by mouse dendritic cells (DC) is controversial. Here, we directly demonstrated substantial production of IFN-γ by DC, as well as hybrid NK-DC, from LVS-infected wild type C57BL/6 or Rag1 knockout mice. We demonstrated that the numbers of conventional DC producing IFN-γ increased progressively over the course of 8 days of LVS infection. In contrast, the numbers of conventional NK cells producing IFN-γ, which represented about 40% of non-B/T IFN-γ-producing cells, peaked at day 4 after LVS infection and declined thereafter. This pattern was similar to that of hybrid NK-DC. To further confirm IFN-γ production by infected cells, DC and neutrophils were sorted from naïve and LVS-infected mice and analyzed for gene expression. Quantification of LVS by PCR revealed the presence of Ft DNA not only in macrophages, but also in highly purified, IFN-γ producing DC and neutrophils. Finally, production of IFN-γ by infected DC was confirmed by immunohistochemistry and confocal microscopy. Notably, IFN-γ production patterns similar to those in wild type mice were observed in cells derived from LVS-infected TLR2, TLR4, and TLR2xTLR9 knockout (KO) mice, but not from MyD88 KO mice. Taken together, these studies demonstrate the pivotal roles of DC and MyD88 in IFN-γ production and in initiating innate immune responses to this intracellular bacterium.


Assuntos
Interferon gama/metabolismo , Fator 88 de Diferenciação Mieloide/genética , Receptores Toll-Like/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Francisella tularensis/imunologia , Imunidade Inata/imunologia , Células Matadoras Naturais/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Mieloides/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Neutrófilos/metabolismo , Baço/metabolismo , Linfócitos T/imunologia , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Receptor Toll-Like 9/metabolismo , Receptores Toll-Like/imunologia , Tularemia/microbiologia
17.
Nature ; 584(7822): 624-629, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32788723

RESUMO

Conventional type 1 dendritic cells (cDC1)1 are thought to perform antigen cross-presentation, which is required to prime CD8+ T cells2,3, whereas cDC2 are specialized for priming CD4+ T cells4,5. CD4+ T cells are also considered to help CD8+ T cell responses through a variety of mechanisms6-11, including a process whereby CD4+ T cells 'license' cDC1 for CD8+ T cell priming12. However, this model has not been directly tested in vivo or in the setting of help-dependent tumour rejection. Here we generated an Xcr1Cre mouse strain to evaluate the cellular interactions that mediate tumour rejection in a model requiring CD4+ and CD8+ T cells. As expected, tumour rejection required cDC1 and CD8+ T cell priming required the expression of major histocompatibility class I molecules by cDC1. Unexpectedly, early priming of CD4+ T cells against tumour-derived antigens also required cDC1, and this was not simply because they transport antigens to lymph nodes for processing by cDC2, as selective deletion of major histocompatibility class II molecules in cDC1 also prevented early CD4+ T cell priming. Furthermore, deletion of either major histocompatibility class II or CD40 in cDC1 impaired tumour rejection, consistent with a role for cognate CD4+ T cell interactions and CD40 signalling in cDC1 licensing. Finally, CD40 signalling in cDC1 was critical not only for CD8+ T cell priming, but also for initial CD4+ T cell activation. Thus, in the setting of tumour-derived antigens, cDC1 function as an autonomous platform capable of antigen processing and priming for both CD4+ and CD8+ T cells and of the direct orchestration of their cross-talk that is required for optimal anti-tumour immunity.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Apresentação Cruzada , Células Dendríticas/imunologia , Neoplasias/imunologia , Animais , Apresentação do Antígeno/imunologia , Linfócitos T CD4-Positivos/citologia , Antígenos CD40/imunologia , Antígenos CD40/metabolismo , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Feminino , Antígenos de Histocompatibilidade Classe II/imunologia , Camundongos , Transdução de Sinais
18.
PLoS Pathog ; 16(7): e1008737, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32726355

RESUMO

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the current COVID-19 pandemic. An unbalanced immune response, characterized by a weak production of type I interferons (IFN-Is) and an exacerbated release of proinflammatory cytokines, contributes to the severe forms of the disease. SARS-CoV-2 is genetically related to SARS-CoV and Middle East respiratory syndrome-related coronavirus (MERS-CoV), which caused outbreaks in 2003 and 2013, respectively. Although IFN treatment gave some encouraging results against SARS-CoV and MERS-CoV in animal models, its potential as a therapeutic against COVID-19 awaits validation. Here, we describe our current knowledge of the complex interplay between SARS-CoV-2 infection and the IFN system, highlighting some of the gaps that need to be filled for a better understanding of the underlying molecular mechanisms. In addition to the conserved IFN evasion strategies that are likely shared with SARS-CoV and MERS-CoV, novel counteraction mechanisms are being discovered in SARS-CoV-2-infected cells. Since the last coronavirus epidemic, we have made considerable progress in understanding the IFN-I response, including its spatiotemporal regulation and the prominent role of plasmacytoid dendritic cells (pDCs), which are the main IFN-I-producing cells. While awaiting the results of the many clinical trials that are evaluating the efficacy of IFN-I alone or in combination with antiviral molecules, we discuss the potential benefits of a well-timed IFN-I treatment and propose strategies to boost pDC-mediated IFN responses during the early stages of viral infection.


Assuntos
Antivirais/uso terapêutico , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/imunologia , Infecções por Coronavirus/tratamento farmacológico , Células Dendríticas/imunologia , Imunidade Inata/imunologia , Interferon Tipo I/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Células Dendríticas/efeitos dos fármacos , Humanos , Imunidade Inata/efeitos dos fármacos , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Prognóstico
20.
PLoS One ; 15(7): e0232307, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667911

RESUMO

In the mammalian gut CD103+ve myeloid DCs are known to suppress inflammation threatened by luminal bacteria, but stimuli driving DC precursor maturation towards this beneficial phenotype are incompletely understood. We isolated CD11+ve DCs from mesenteric lymph nodes (MLNs) of healthy mice; CD103+ve DCs were 8-24 fold more likely than CD103-ve DCs to exhibit extensive of prior phagocytosis of apoptotic intestinal epithelial cells. However, CD103+ve and CD103-ve MLN DCs exhibited similar ex vivo capacity to ingest apoptotic cells, indicating that apoptotic cells might drive immature DC maturation towards the CD103+ve phenotype. When cultured with apoptotic cells, myeloid DC precursors isolated from murine bone marrow and characterised as lineage-ve CD103-ve, displayed enhanced expression of CD103 and ß8 integrin and acquired increased capacity to induce T regulatory lymphocytes (Tregs) after 7d in vitro. However, DC precursors isolated from αv-tie2 mice lacking αv integrins in the myeloid line exhibited reduced binding of apoptotic cells and complete deficiency in the capacity of apoptotic cells and/or latent TGF-ß1 to enhance CD103 expression in culture, whereas active TGF-ß1 increased DC precursor CD103 expression irrespective of αv expression. Fluorescence microscopy revealed clustering of αv integrin chains and latent TGF-ß1 at points of contact between DC precursors and apoptotic cells. We conclude that myeloid DC precursors can deploy αv integrin to orchestrate binding of apoptotic cells, activation of latent TGF-ß1 and acquisition of the immunoregulatory CD103+ve ß8+ve DC phenotype. This implies that a hitherto unrecognised consequence of apoptotic cell interaction with myeloid phagocytes is programming that prevents inflammation.


Assuntos
Antígenos CD/metabolismo , Apoptose , Células Dendríticas/imunologia , Regulação da Expressão Gênica , Imunomodulação , Cadeias alfa de Integrinas/metabolismo , Integrina alfaV/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Animais , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Feminino , Camundongos Endogâmicos C57BL , Células Mieloides/citologia , Fagocitose , Linfócitos T Reguladores/imunologia
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