RESUMO
The assessment of amphibian responses as bioindicators of exposure to chemical pollutants is an important tool for conservation of native species. This study aimed to investigate the effects of chronic aluminum (Al) and zinc (Zn) exposure on survival, body size, morphology (malformations), and immune system (leukocyte profile) in P. cuvieri tadpoles. Ecotoxicological analyses were performed utilizing chronic toxicity tests in which 210 tadpoles at the 25th Gosner developmental stage were exposed to Al and Zn. Individuals of P. cuvieri were maintained in glass containers containing various concentrations of aluminum sulfate (0.1, 0.2, or 0.3 mg/L) and zinc sulfate (0.18, 0.27 or 0.35 mg/L), and tests were performed in triplicate. After 14 days, amphibians were weighed, measured and survival rate, malformations in the oral and intestine apparatus, leukocyte profile, and ratio between neutrophils and lymphocytes determined. The differing concentrations of Al and Zn did not produce lethality in P. cuvieri where 95% of the animals survived 326 hr following metal exposure. Individuals exposed to Zn achieved greater body growth and weight gain compared to controls. Aluminum increased weight gain compared controls. These metals also produced malformations of the oral and intestine apparatus and enhanced occurrence of hemorrhages, especially at the highest doses. Lymphocytes were the predominant cells among leukocytes, with lymphopenia and neutrophilia observed following Al and Zn treatment, as evidenced by elevated neutrophil/lymphocyte ratio, an important indicator of stress in animals. Data suggest that further studies need to be carried out, even with metal concentrations higher than those prescribed by CONAMA, to ensure the conservation of this species.
Assuntos
Poluentes Químicos da Água , Zinco , Humanos , Animais , Zinco/farmacologia , Zinco/toxicidade , Alumínio/farmacologia , Larva , Anuros/fisiologia , Metais , Sistema Imunitário/química , Tamanho Corporal , Aumento de Peso , Poluentes Químicos da Água/toxicidadeRESUMO
BACKGROUND: The fetus grows in a sterile womb environment. After birth, the newborn immune system has two immediate hurdles to clear. First immediate suppression of the womb compatible immune system and turn on the immune system of the newborn that can counter the antigenic world. The underlying mechanism of immune fluctuation by milk microRNAs (miRNAs) can be crucial for the treatment of critical or premature newborn. METHODS: We collected fourteen samples of each colostrum and mature milk from lactating mothers, four samples of each were used for microarray analysis, and the other ten were used for miRNA expression profiling by real-time PCR. RESULTS: From the microarray, 154 differentially expressed miRNAs were identified, whereas 49 miRNAs were revealed as immune-related miRNAs based on a literature study. Among the 49 miRNAs, 33 were already shown as strongly validated immune-related miRNAs (validated by qPCR, Western Blot, and Luciferase assay) and were considered for further analysis. Twenty-two miRNA expressions were analysed by real-time PCR as their Ct values were within considerable limits. Twelve numbers of miRNAs were significantly downregulated in mature milk compared to colostrum, which were again subjected to bioinformatics analysis to predict the biological mechanisms behind the differentially expressed miRNAs. CONCLUSION: This study shed light on the human milk exosome miRNA expression dynamics during lactation and their possible role in the gradual skewing of the newborns' immune system. The information is crucial for the development and onset of sepsis in premature newborns in the NICU.
Assuntos
Exossomos , MicroRNAs , Gravidez , Feminino , Recém-Nascido , Humanos , Colostro , Exossomos/genética , Exossomos/metabolismo , Lactação/genética , MicroRNAs/genética , Leite Humano , Sistema Imunitário/química , Sistema Imunitário/metabolismo , Perfilação da Expressão GênicaRESUMO
WHAT IS KNOWN ABOUT THE ACTION OF ENDOCRINE DISRUPTORS ON THE IMMUNE SYSTEM? The immune system (innate and adaptive immunity), involves different tissues and cell types to defend the body against external aggressions. This physiological mechanism involves some hormonal systems for its proper functioning. Moreover, new relationships between the immune system and endocrine processes have been recently described. Immunotoxicology is therefore a rapidly expanding field of research. Many environmental pollutants, such as organochlorine pesticides, polycyclic aromatic hydrocarbons or heavy metals, have an impact on the immune response leading either to a deficiency or a hyperactivation (autoimmune disease, allergy). More recently, other endocrine disruptors such as organofluorines are suspected to be immunotoxic. Low-level exposure to pollutants in the general population probably does not explain the development of all the pathologies, but it sentisizes organisms to the development of these pathologies, weakening certain key processes of the immune system.
QUE SAIT-ON DE L'ACTION DES PERTURBATEURS ENDOCRINIENS SUR LE SYSTÈME IMMUNITAIRE ? Le système immunitaire, composé de l'immunité innée et l'immunité adaptative, met en jeu différents tissus et types cellulaires afin de défendre l'organisme contre les agressions extérieures. Le bon fonctionnement de ce mécanisme physiologique implique quelques systèmes hormonaux. Par ailleurs, de nouvelles relations entre le système immunitaire et des processus endocriniens ont été récemment décrites. L'immunotoxicologie est donc un domaine de recherche en pleine expansion. Un grand nombre de polluants environnementaux, comme des pesticides organochlorés, des hydrocarbures aromatiques polycycliques ou des métaux lourds, impactent la réponse immunitaire, conduisant soit à une déficience soit à une hyperactivation (maladie auto-immune, allergie). Depuis peu, d'autres perturbateurs endocriniens comme les organofluorés sont suspectés d'exercer des effets immunotoxiques. L'exposition de la population générale aux polluants, à bas bruit, n'explique probablement pas le développement de l'ensemble des pathologies observées mais rend les organismes susceptibles de développer ces pathologies, en contribuant à fragiliser certains processus clés du système immunitaire.
Assuntos
Disruptores Endócrinos , Poluentes Ambientais , Hipersensibilidade , Hidrocarbonetos Policíclicos Aromáticos , Disruptores Endócrinos/toxicidade , Poluentes Ambientais/toxicidade , Humanos , Sistema Imunitário/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/toxicidadeRESUMO
Limitations associated with immunoglobulins have motivated the search for novel binding scaffolds. Repeat proteins have emerged as one promising class of scaffolds, but often are limited to binding protein and peptide targets. An exception is the repeat proteins of the immune system, which have in recent years served as an inspiration for binding scaffolds which can bind glycans and other classes of biomolecule. Like other repeat proteins, these proteins can be very stable and have a monomeric mode of binding, with elongated and highly variable binding surfaces. The ability to target glycans and glycoproteins fill an important gap in current tools for research and biomedical applications.
Assuntos
Proteínas de Transporte/química , Sistema Imunitário/química , Imunoglobulinas/química , Engenharia de Proteínas/métodos , Sequências Repetitivas de Aminoácidos/genética , Motivos de Aminoácidos/genética , Sequência de Aminoácidos/genética , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Humanos , Sistema Imunitário/metabolismo , Imunoglobulinas/metabolismo , Proteínas NLR/química , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Domínios Proteicos/genética , Receptores Toll-Like/químicaRESUMO
In immunology, the resolution of complex chemical mixtures familiar from omics, comes with an added layer of hierarchy: bioactive immunological surface markers are embedded on the cell membranes of e.g. white blood cells. Therefore, each blood sample actually consists of a comprehensive mixture of cells. The cells need to be resolved based on their surface marker chemistry, to investigate their involvement in an immune response. This mixture may be measured on a single-cell level with Multicolour Flow Cytometry (MFC). Finding such cellular and molecular markers is of the utmost academic and diagnostic importance. Several advanced data analysis methods therefore aim to meet the considerable data challenge of resolving such cell mixtures. These multivariate methods are more resource-efficient than the manual analysis of MFC data, called sequential gating, but also likely provide additional biomedical insight compared to the conventional bivariate approach. To compare such methods more comprehensively than has been done until now, we have developed a list of criteria on how each method recovers the information on both the cell and the underlying molecular levels on an MFC sample of an asthma patient. We compare these methods for the chemometric data analysis commonly used in metabolomics. This shows that all compared methods have their own advantage in recovering the sequential gating results, giving insight into the limitations of sequential gating, providing insight into the chemical relationships between cells within the mixture and resolving information related to chemical heterogeneities between cells. We furthermore show how comparative analyses of different samples may lead to further insight into the subdivision of cells into different types based on their immunological involvement in asthma development, and how sparsity-a currently popular method to enhance the discriminative ability of multivariate models-may reduce the insight into the underlying hierarchical variability in cell chemistry. Although developed for cytometry, the presented chemometrics will be highly valuable to many more chemical systems where hierarchical arrangement of the molecules plays a crucial role.
Assuntos
Asma/diagnóstico , Sistema Imunitário/química , Adulto , Idoso , Asma/sangue , Asma/imunologia , Citometria de Fluxo , Humanos , Sistema Imunitário/imunologia , Aprendizado de Máquina , Pessoa de Meia-Idade , Adulto JovemRESUMO
Siglecs are a family of receptor-type glycan recognition proteins (lectins) involved in self-nonself discrimination by the immune system. Identification of Siglec ligands is necessary to understand how Siglec-ligand interaction translates into biological outcomes. However, this is challenging because the interaction is weak. To facilitate identification of Siglec ligands, we adopted a proximity labeling method based on the tyramide radicalization principle. Cells that express Siglec ligands were labeled with Siglec-peroxidase complexes and incubated with biotin tyramide and hydrogen peroxide to generate short-lived tyramide radicals that covalently label the proteins near the Siglec-peroxidase complex. A proof-of-principle experiment using CD22 (Siglec-2) probe identified its known ligands on B cells, including CD22 itself, CD45, and IgM, among others, demonstrating the validity of this method. The specificity of labeling was confirmed by sialidase treatment of target cells and using glycan recognition-deficient mutant CD22 probes. Moreover, possible interactions between biotin-labeled proteins were revealed by literature-based protein-protein interaction network analysis, implying the presence of a molecular cluster comprising CD22 ligands. Further application of this method identified CD44 as a hitherto unknown Siglec-15 ligand on RAW264.7-derived osteoclasts. These results demonstrated the utility of proximity labeling for the identification of Siglec ligands, which may extend to other lectins.
Assuntos
Linfócitos B/imunologia , Sistema Imunitário/imunologia , Lectinas/imunologia , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/imunologia , Animais , Biotina/química , Radicais Livres/química , Humanos , Peróxido de Hidrogênio/química , Sistema Imunitário/química , Imunoglobulina M/imunologia , Lectinas/metabolismo , Antígenos Comuns de Leucócito/imunologia , Ligantes , Camundongos , Células RAW 264.7 , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/química , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/metabolismo , Coloração e Rotulagem , Tiramina/químicaRESUMO
Occurrence of polycyclic aromatic hydrocarbon (PAH) contamination in the marine environment represents a risk to marine life and humans. In this study, plasma samples from Atlantic cod (Gadus morhua) were analysed by shotgun mass spectrometry to investigate the plasma proteome in response to exposure to single PAHs (naphthalene or chrysene) and their corresponding metabolites (dihydrodiols). In total, 369 proteins were identified and ranked according to their relative abundance. The levels of 12 proteins were found significantly altered in PAH exposed fish and are proposed as new biomarker candidates. Eleven proteins were upregulated, primarily immunoglobulin components, and one protein was downregulated (antifreeze protein type IV.) The uniformity of the upregulated proteins suggests a triggered immune response in the exposed fish. Overall, the results provide valuable knowledge for future studies of the Atlantic cod plasma proteome and generate grounds for establishing new plasma protein biomarkers for environmental monitoring of PAH related exposure.
Assuntos
Gadus morhua/sangue , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Animais , Biomarcadores/sangue , Feminino , Peixes/sangue , Peixes/metabolismo , Gadus morhua/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Sistema Imunitário/química , Sistema Imunitário/efeitos dos fármacos , Espectrometria de Massas , Plasma/química , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Proteoma/metabolismo , Poluentes Químicos da Água/farmacologiaRESUMO
INTRODUCTION: A postpartum diagnosis of breast cancer is an independent predictor of metastases, however the reason is unknown. In rodents, the window of postpartum mammary gland involution promotes tumor progression, suggesting a role for breast involution in the poor prognosis of human postpartum breast cancers. Rodent mammary gland involution is characterized by the programmed elimination of the secretory lobules laid down in preparation for lactation. This tissue involution process involves massive epithelial cell death, stromal remodeling, and immune cell infiltration with similarities to microenvironments present during wound healing and tumor progression. Here, we characterize breast tissue from premenopausal women with known reproductive histories to determine the extent, duration and cellular mechanisms of postpartum lobular involution in women. METHODS: Adjacent normal breast tissues from premenopausal women (n = 183) aged 20 to 45 years, grouped by reproductive categories of nulliparous, pregnant and lactating, and by time since last delivery were evaluated histologically and by special stain for lobular area, lobular type composition, apoptosis and immune cell infiltration using computer assisted quantitative methods. RESULTS: Human nulliparous glands were composed dominantly of small (approximately 10 acini per lobule) and medium (approximately 35 acini per lobule) sized lobules. With pregnancy and lactation, a >10 fold increase in breast epithelial area was observed compared to nulliparous cases, and lactating glands were dominated by mature lobules (>100 acini per lobule) with secretory morphology. Significant losses in mammary epithelial area and mature lobule phenotypes were observed within 12 months postpartum. By 18 months postpartum, lobular area content and lobule composition were indistinguishable from nulliparous cases, data consistent with postpartum involution facilitating regression of the secretory lobules developed in preparation for lactation. Analyses of apoptosis and immune cell infiltrate confirmed that human postpartum breast involution is characterized by wound healing-like tissue remodeling programs that occur within a narrowed time frame. CONCLUSIONS: Human postpartum breast involution is a dominant tissue-remodeling process that returns the total lobular area of the gland to a level essentially indistinguishable from the nulliparous gland. Further research is warranted to determine whether the normal physiologic process of postpartum involution contributes to the poor prognosis of postpartum breast cancer.
Assuntos
Apoptose/fisiologia , Mama/fisiologia , Proliferação de Células , Células Epiteliais/fisiologia , Período Pós-Parto/fisiologia , Adulto , Análise de Variância , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Mama/química , Mama/citologia , Feminino , Humanos , Sistema Imunitário/química , Sistema Imunitário/citologia , Imuno-Histoquímica , Antígeno Ki-67/análise , Lactação , Antígenos Comuns de Leucócito/análise , Pessoa de Meia-Idade , Paridade , Gravidez , Pré-Menopausa , Adulto JovemRESUMO
Flaviviruses, the human pathogens responsible for dengue fever, West Nile fever, tick-borne encephalitis, and yellow fever, are endemic in tropical and temperate parts of the world. The flavivirus nonstructural protein 1 (NS1) functions in genome replication as an intracellular dimer and in immune system evasion as a secreted hexamer. We report crystal structures for full-length, glycosylated NS1 from West Nile and dengue viruses. The NS1 hexamer in crystal structures is similar to a solution hexamer visualized by single-particle electron microscopy. Recombinant NS1 binds to lipid bilayers and remodels large liposomes into lipoprotein nanoparticles. The NS1 structures reveal distinct domains for membrane association of the dimer and interactions with the immune system and are a basis for elucidating the molecular mechanism of NS1 function.
Assuntos
Membrana Celular/virologia , Sistema Imunitário/virologia , Proteínas não Estruturais Virais/química , Membrana Celular/química , Cristalografia por Raios X , Proteína DEAD-box 58 , RNA Helicases DEAD-box/química , RNA Helicases DEAD-box/imunologia , Humanos , Interações Hidrofóbicas e Hidrofílicas , Sistema Imunitário/química , Imunidade Inata , Bicamadas Lipídicas , Microscopia Eletrônica , Conformação Proteica , Multimerização Proteica , Receptores Imunológicos , Proteínas não Estruturais Virais/imunologiaRESUMO
Coelomocytes are considered to be immune effectors of sea urchins. Coelomocytes are the freely circulating cells in the body fluid contained in echinoderm coelom and mediate the cellular defence responses to immune challenges by phagocytosis, encapsulation, cytotoxicity and the production of antimicrobial agents. Coelomocytes have the ability to recognize self from non-self. Considering that sialic acids play important roles in immunity, we determined the presence of sialic acid types in coelomocytes of Paracentrotus lividus. Homogenized coelomocytes were kept in 2 M aqueous acetic acid at 80 °C for 3 h to liberate sialic acids. Sialic acids were determined by derivatization with 1,2-diamino-4,5-methylenediaoxy-benzene dihydrochloride (DMB) followed by capillary liquid-chromatography-electrospray ionization/tandem mass spectrometry (CapLC-ESI-MS/MS). Standard sialic acids; Neu5Ac, Neu5Gc, KDN and bovine submaxillary mucin showing a variety of sialic acids were used to confirm sialic acids types. We found ten different types of sialic acids (Neu5Gc, Neu5Ac, Neu5Gc9Ac, Neu5Gc8Ac, Neu5,9Ac2, Neu5,7Ac2, Neu5,8Ac2, Neu5,7,9Ac3, Neu5Gc7,9Ac2, Neu5Gc7Ac) isolated in limited amounts from total coelomocyte population. Neu5Gc type of sialic acids in coelomocytes was the most abundant type sialic acid when compared with other types. This is the first report on the presence of sialic acid types in coelomocytes of P. lividus using CapLC-ESI-MS/MS-Ion Trap system (Capillary Liquid Chromatography-Electrospray Ionization/Tandem Mass Spectrometry).
Assuntos
Sistema Imunitário/química , Paracentrotus/química , Ácidos Siálicos/análise , Animais , Cromatografia Líquida , Sistema Imunitário/citologia , Sistema Imunitário/imunologia , Paracentrotus/citologia , Paracentrotus/imunologia , Ácidos Siálicos/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em TandemRESUMO
Calreticulin is a calcium-binding chaperone that has several functions in the immune response. In the endoplasmic reticulum (ER), calreticulin facilitates the folding of major histocompatibility complex (MHC) class I molecules and their assembly factor tapasin, thereby influencing antigen presentation to cytotoxic T cells. Although calreticulin is normally ER-resident, it is found at the cell surface of living cancer cells and dying cells. Here, calreticulin promotes cellular phagocytic uptake. In tumor vaccine models, drugs that induce cell surface calreticulin confer enhanced tumor protection in an extracellular calreticulin-dependent manner. Much remains to be understood about the roles of calreticulin in these distinct functions. Further investigations are important towards advancing basic knowledge of glycoprotein-folding pathways, and towards developing new cancer therapeutic strategies.
Assuntos
Calreticulina/imunologia , Sistema Imunitário/imunologia , Animais , Calreticulina/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Sistema Imunitário/química , Espaço Intracelular/imunologia , Fagócitos/imunologia , Dobramento de ProteínaRESUMO
Molecular dynamics simulations have to be sufficiently long to draw reliable conclusions. However, no method exists to prove that a simulation has converged. We suggest the method of "lagged RMSD-analysis" as a tool to judge if an MD simulation has not yet run long enough. The analysis is based on RMSD values between pairs of configurations separated by variable time intervals Δt. Unless RMSD(Δt) has reached a stationary shape, the simulation has not yet converged.
Assuntos
Biologia Computacional/métodos , Simulação de Dinâmica Molecular , Algoritmos , Animais , Simulação por Computador , Humanos , Sistema Imunitário/química , Modelos Moleculares , Modelos Estatísticos , Modelos Teóricos , Conformação Molecular , Proteínas/química , Receptores de Antígenos de Linfócitos T/química , Reprodutibilidade dos Testes , Fatores de TempoRESUMO
The immune system is highly evolved and can respond to infection throughout the body. Pathogenspecific immune cells are usually generated in secondary lymphoid tissues (e.g., spleen, lymph nodes) and then migrate to sites of infection where their functionality is shaped by the local milieu. Because immune cells are so heavily influenced by the infected tissue in which they reside, it is important that their interactions and dynamics be studied in vivo. Two-photon microscopy is a powerful approach to study host-immune interactions in living tissues, and recent technical advances in the field have enabled researchers to capture movies of immune cells and infectious agents operating in real time. These studies have shed light on pathogen entry and spread through intact tissues as well as the mechanisms by which innate and adaptive immune cells participate in thwarting infections. This review focuses on how two-photon microscopy can be used to study tissue-specific immune responses in vivo, and how this approach has advanced our understanding of host-immune interactions following infection.
Assuntos
Interações Hospedeiro-Patógeno , Sistema Imunitário/química , Infecções/imunologia , Tecido Linfoide/química , Animais , Diagnóstico por Imagem , Humanos , Sistema Imunitário/imunologia , Infecções/diagnóstico , Infecções/microbiologia , Infecções/virologia , Tecido Linfoide/imunologia , MicroscopiaRESUMO
The proteomic response to bacterial infection in a teleost fish (Paralichthys olivaceus) infected with Streptococcus parauberis was analyzed using label-free protein quantitation coupled with LC-MS(E) tandem mass spectrometry. A total of 82 proteins from whole kidney, a major lymphoid organ in this fish, were found to be differentially expressed between healthy and diseased fish analyzed 6, 24, 72 and 120 h post-infection. Among the differentially expressed proteins, those involved in mediating immune responses (e.g., heat shock proteins, cathepsins, goose-type lysozyme and complement components) were most significantly up-regulated by infection. In addition, cell division cycle 48 (CDC48) and calreticulin, which are associated with cellular recovery and glycoprotein synthesis, were up-regulated in the universal protein group, whereas the other proteins in that group were down-regulated. There was continuous activation of expression of immune-associated proteins during infection, but there was also loss of expression of proteins not involved in immune function. We expect that our findings regarding immune response at the protein level would offer new insight into the systemic response to bacterial infection of a major immune organ in teleost fish.
Assuntos
Imunidade Adaptativa , Doenças dos Peixes/metabolismo , Linguado/metabolismo , Rim/metabolismo , Proteoma/análise , Infecções Estreptocócicas/metabolismo , Streptococcus/imunologia , Imunidade Adaptativa/fisiologia , Animais , Análise por Conglomerados , Doenças dos Peixes/imunologia , Linguado/imunologia , Sistema Imunitário/química , Sistema Imunitário/metabolismo , Rim/química , Rim/imunologia , Modelos Biológicos , Proteoma/metabolismo , Infecções Estreptocócicas/imunologia , Distribuição TecidualRESUMO
Among the different proteoglycans expressed by mammals, serglycin is in most immune cells the dominating species. A unique property of serglycin is its ability to adopt highly divergent structures, because of glycosylation with variable types of glycosaminoglycans when expressed by different cell types. Recent studies of serglycin-deficient animals have revealed crucial functions for serglycin in a diverse array of immunological processes. However, its exact function varies to a large extent depending on the cellular context of serglycin expression. Based on these findings, serglycin is emerging as a structural and functional chameleon, with radically different properties depending on its exact cellular and immunological context.
Assuntos
Sistema Imunitário/citologia , Proteoglicanas/química , Proteoglicanas/fisiologia , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/fisiologia , Animais , Regulação da Expressão Gênica/imunologia , Humanos , Sistema Imunitário/química , Sistema Imunitário/metabolismo , Proteoglicanas/biossíntese , Vesículas Secretórias/imunologia , Vesículas Secretórias/metabolismo , Relação Estrutura-Atividade , Proteínas de Transporte Vesicular/biossínteseRESUMO
The classical protein structure-function paradigm has been challenged by the emergence of intrinsically disordered proteins (IDPs), the proteins that do not adopt well-defined three-dimensional structures under physiological conditions. This development was accompanied by the introduction of a "coupled binding and folding" paradigm that suggests folding of IDPs upon binding to their partners. However, our recent studies challenge this general view by revealing a novel, previously unrecognized phenomenon - uncoupled binding and folding. This biologically important mechanism is characteristic of members of a new family of IDPs involved in immune signaling and underlies their unusual properties including: (1) specific homodimerization, (2) the lack of folding upon binding to a well-folded protein, another IDP molecule, or to lipid bilayer membranes, and (3) the "scissors-cut paradox". The third phenomenon occurs in diverse IDP interactions and suggests that properties of IDP fragments are not necessarily additive in the context of the entire protein. The "no disorder-to-order transition" type of binding is distinct from known IDP interactions and is characterized by an unprecedented observation of the lack of chemical shift and peak intensity changes in multidimensional NMR spectra, a fingerprint of proteins, upon complex formation. Here, I focus on those interactions of IDPs with diverse biological partners where the binding phase driven by electrostatic interactions is not be necessarily followed by the hydrophobic folding phase. I also review new multidisciplinary knowledge about immune signaling-related IDPs and show how it expands our understanding of cell function with multiple applications in biology and medicine.
Assuntos
Sistema Imunitário/metabolismo , Dobramento de Proteína , Proteínas/química , Proteínas/metabolismo , Sistema Imunitário/química , Sistema Imunitário/patologia , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Proteínas/genética , Transdução de SinaisRESUMO
Systems biology is an emerging discipline that combines high-content, multiplexed measurements with informatic and computational modeling methods to better understand biological function at various scales. Here we present a detailed review of the methods used to create computational models and to conduct simulations of immune function. We provide descriptions of the key data-gathering techniques employed to generate the quantitative and qualitative data required for such modeling and simulation and summarize the progress to date in applying these tools and techniques to questions of immunological interest, including infectious disease. We include comments on what insights modeling can provide that complement information obtained from the more familiar experimental discovery methods used by most investigators and the reasons why quantitative methods are needed to eventually produce a better understanding of immune system operation in health and disease.
Assuntos
Sistema Imunitário/citologia , Modelos Imunológicos , Biologia de Sistemas/métodos , Animais , Simulação por Computador , Humanos , Sistema Imunitário/química , Infecções/genética , Infecções/imunologiaRESUMO
Rationally designing new strategies to control the human immune response stands as a key challenge for the scientific community. Chemical biologists have the opportunity to address specific issues in this area that have important implications for both basic science and clinical medicine.
Assuntos
Sistema Imunitário/química , Sistema Imunitário/efeitos dos fármacos , Imunidade/efeitos dos fármacos , Biologia Sintética/tendências , Animais , Diferenciação Celular/fisiologia , Humanos , Imunidade Celular/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas , Vacinas/química , Vacinas/uso terapêuticoRESUMO
Human APOBEC3 enzymes are cellular DNA cytidine deaminases that inhibit and/or mutate a variety of retroviruses, retrotransposons, and DNA viruses. Here, we report a detailed examination of human APOBEC3 gene expression, focusing on APOBEC3G (A3G) and APOBEC3F (A3F), which are potent inhibitors of human immunodeficiency virus type 1 (HIV-1) infection but are suppressed by HIV-1 Vif. A3G and A3F are expressed widely in hematopoietic cell populations, including T cells, B cells, and myeloid cells, as well as in tissues where mRNA levels broadly correlate with the lymphoid cell content (gonadal tissues are exceptions). By measuring mRNA copy numbers, we find that A3G mRNA is approximately 10-fold more abundant than A3F mRNA, implying that A3G is the more significant anti-HIV-1 factor in vivo. A3G and A3F levels also vary between donors, and these differences are sustained over 12 months. Responses to T-cell activation or cytokines reveal that A3G and A3F mRNA levels are induced approximately 10-fold in macrophages and dendritic cells (DCs) by alpha interferon (IFN-alpha) and approximately 4-fold in naïve CD4(+) T cells. However, immunoblotting revealed that A3G protein levels are induced by IFN-alpha in macrophages and DCs but not in T cells. In contrast, T-cell activation and IFN-gamma had a minimal impact on A3G or A3F expression. Finally, we noted that A3A mRNA expression and protein expression are exquisitely sensitive to IFN-alpha induction in CD4(+) T cells, macrophages, and DCs but not to T-cell activation or other cytokines. Given that A3A does not affect HIV-1 infection, these observations imply that this protein may participate in early antiviral innate immune responses.
Assuntos
Citidina Desaminase/genética , Citosina Desaminase/genética , Células-Tronco Hematopoéticas/citologia , Imunidade Inata , Desaminase APOBEC-3G , Infecções por HIV/imunologia , Sistema Hematopoético/química , Sistema Hematopoético/citologia , Humanos , Sistema Imunitário/química , Sistema Imunitário/citologia , Interferon-alfa/farmacologia , RNA Mensageiro/análise , Distribuição Tecidual , Ativação Transcricional/efeitos dos fármacosRESUMO
A H1x-like protein (i.e., NCAMP-1) is expressed on the membrane and in GEs from fish NK-like cells. In the present study, we identify the imprinting control region mouse NCAMP-1 ortholog using NCAMP-1 polyclonal antibodies and mAb. Polychromatic flow cytometry revealed NCAMP-1 expression on PBLs (Gr-1(+) PMNs were 21.1% NCAMP-1(+); DX-5(+) NK cells were 12.2% NCAMP-1(+)), mesenteric LN cells (CD11c(+) DCs were 23.2% NCAMP-1(+); Gr-1(+) PMNs were 24.8% NCAMP-1(+); CD21(+) B cells were 17.8% NCAMP-1(+)), and splenocytes (CD11c(+) were 39.6% NCAMP-1(+); Gr-1(+) PMNs were 40.9% NCAMP-1(+); DX-5(+) NK cells were 24.3% NCAMP-1(+); CD21(+) B cells were 28.5% NCAMP-1(+)). Western blot analysis using pNCAMP-1 and GEs from RAW 264.7 cells produced a 32-kDa signal. GEs from RAW 264.7 cells produced a significant reduction in Escherichia coli CFU. This antimicrobial killing activity was inhibited by pretreatment of the extract with (polyclonal) anti-NCAMP-1. Treatment with preimmune serum did not reduce bacterial cell killing. Confocal microscopy using NCAMP-1 and LAMP-1 mAb demonstrated that NCAMP-1 was located on the membrane and in cytosolic vesicles of RAW 264.7 cells and did not appear to colocalize with LAMP-1. NCAMP-1 may participate as a bifunctional protein on cells. It is expressed on the membranes of phagocytic cells, NK cells, and APCs in mice as well as in the granules of macrophages. In phagocytic cells, NCAMP-1 may participate in a nonregulated exocytosis pathway of cellular secretion.