INTRODUCTION: Red blood cells (RBCs), also known as erythrocytes, are underestimated in their role in the immune system. In mammals, erythrocytes undergo maturation that involves the loss of nuclei, resulting in limited transcription and protein synthesis capabilities. However, the nucleated nature of non-mammalian RBCs is challenging this conventional understanding of RBCs. Notably, in bony fishes, research indicates that RBCs are not only susceptible to pathogen attacks but express immune receptors and effector molecules. However, given the abundance of RBCs and their interaction with every physiological system, we postulate that they act in surveillance as sentinels, rapid responders, and messengers. METHODS: We performed a series of in vitro experiments with Cyprinus carpio RBCs exposed to Aeromonas hydrophila, as well as in vivo laboratory infections using different concentrations of bacteria. RESULTS: qPCR revealed that RBCs express genes of several inflammatory cytokines. Using cyprinid-specific antibodies, we confirmed that RBCs secreted tumor necrosis factor alpha (TNFα) and interferon gamma (IFNγ). In contrast to these indirect immune mechanisms, we observed that RBCs produce reactive oxygen species and, through transmission electron and confocal microscopy, that RBCs can engulf particles. Finally, RBCs expressed and upregulated several putative toll-like receptors, including tlr4 and tlr9, in response to A. hydrophila infection in vivo. DISCUSSION: Overall, the RBC repertoire of pattern recognition receptors, their secretion of effector molecules, and their swift response make them immune sentinels capable of rapidly detecting and signaling the presence of foreign pathogens. By studying the interaction between a bacterium and erythrocytes, we provide novel insights into how the latter may contribute to overall innate and adaptive immune responses of teleost fishes.
- MeSH
- Aeromonas hydrophila * immunology MeSH
- Cytokines * metabolism immunology MeSH
- Erythrocytes * immunology metabolism MeSH
- Phagocytosis immunology MeSH
- Gram-Negative Bacterial Infections * immunology MeSH
- Carps * immunology microbiology MeSH
- Fish Diseases * immunology microbiology MeSH
- Pathogen-Associated Molecular Pattern Molecules immunology MeSH
- Immunity, Innate MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
The existence of pattern recognition receptors (PRRs) on immune cells was discussed in 1989 by Charles Janeway, Jr., who proposed a general concept of the ability of PRRs to recognize and bind conserved molecular structures of microorganisms known as pathogen-associated molecular patterns (PAMPs). Upon PAMP engagement, PRRs trigger intracellular signaling cascades resulting in the expression of various proinflammatory molecules. These recognition molecules represent an important and efficient innate immunity tool of all organisms. As invertebrates lack the instruments of the adaptive immune system, based on "true" lymphocytes and functional antibodies, the importance of PRRs are even more fundamental. In the present review, the structure, specificity, and expression profiles of PRRs characterized in annelids are discussed, and their role in innate defense is suggested.
- MeSH
- Annelida immunology MeSH
- Membrane Glycoproteins chemistry genetics metabolism MeSH
- Pathogen-Associated Molecular Pattern Molecules immunology metabolism MeSH
- Immunity, Innate * MeSH
- Acute-Phase Proteins chemistry genetics metabolism MeSH
- Receptors, Pattern Recognition chemistry genetics metabolism MeSH
- Gene Expression Regulation MeSH
- Signal Transduction immunology MeSH
- Tissue Distribution MeSH
- Toll-Like Receptors chemistry genetics metabolism MeSH
- Carrier Proteins chemistry genetics metabolism MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Cytokinins are plant hormones with biological functions ranging from coordination of plant growth to the regulation of biotic and abiotic stress-related responses and senescence. The components of the plant immune system can learn from past elicitations by microbial pathogens and herbivores and adapt to new threats. It is known that plants can enter the primed state of enhanced defense induced by either natural or synthetic compounds. While the involvement of cytokinins in defense priming has been documented, no comprehensive model of their action has been provided to date. Here, we report the functional characterization of two aromatic cytokinin derivatives, 6-benzylaminopurine-9-arabinosides (BAPAs), 3-methoxy-BAPA and 3-hydroxy-BAPA, that proved to be effective in delaying senescence in detached leaves while having low interactions with the cytokinin pathway. An RNA-seq profiling study on Arabidopsis leaves treated with 3-methoxy-BAPA revealed that short and extended treatments with this compound shifted the transcriptional response markedly toward defense. Both treatments revealed upregulation of genes involved in processes associated with plant innate immunity such as cell wall remodeling and upregulation of specific MAP kinases, most importantly MPK11, which is a MAPK module involved in stress-related signaling during the pathogen-associated molecular patterns (PAMPs) response. In addition, elevated levels of JA and its metabolites, jasmonate/ethylene-driven upregulation of PLANT DEFENSIN 1.2 (PDF1.2) and other defensins, and also temporarily elevated levels of reactive oxygen species marked the plant response to 3-methoxy-BAPA treatment. Synergistic interactions were observed when plants were cotreated with 3-hydroxy-BAPA and the flagellin-derived bacterial PAMP peptide (flg22), leading to the enhanced expression of the PAMP-triggered immunity (PTI) marker gene FRK1. Our data collectively show that some BAPAs can sensitively prime the PTI responses in a low micromolar range of concentrations while having no observable negative effects on the overall fitness of the plant.
- MeSH
- Arabidopsis chemistry metabolism MeSH
- Arabinonucleosides chemistry pharmacology MeSH
- Cytokinins chemistry pharmacology MeSH
- Plant Immunity drug effects MeSH
- Plant Leaves drug effects MeSH
- MAP Kinase Signaling System drug effects MeSH
- Mitogen-Activated Protein Kinases genetics metabolism MeSH
- Molecular Structure MeSH
- Pathogen-Associated Molecular Pattern Molecules pharmacology MeSH
- Arabidopsis Proteins genetics metabolism MeSH
- Gene Expression Regulation, Plant drug effects MeSH
- Structure-Activity Relationship MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Primary interaction of an intracellular bacterium with its host cell is initiated by activation of multiple signaling pathways in response to bacterium recognition itself or as cellular responses to stress induced by the bacterium. The leading molecules in these processes are cell surface membrane receptors as well as cytosolic pattern recognition receptors recognizing pathogen-associated molecular patterns or damage-associated molecular patterns induced by the invading bacterium. In this review, we demonstrate possible sequences of events leading to recognition of Francisella tularensis, present findings on known mechanisms for manipulating cell responses to protect Francisella from being killed, and discuss newly published data from the perspective of early stages of host-pathogen interaction.
- MeSH
- Alarmins genetics immunology MeSH
- Bacterial Proteins genetics immunology MeSH
- Phagocytosis genetics MeSH
- Francisella tularensis genetics immunology pathogenicity MeSH
- Host-Pathogen Interactions genetics immunology MeSH
- Humans MeSH
- Macrophages immunology microbiology MeSH
- Pathogen-Associated Molecular Pattern Molecules immunology metabolism MeSH
- Immunity, Innate * MeSH
- Receptors, Cell Surface genetics immunology MeSH
- Receptors, Pattern Recognition genetics immunology MeSH
- Gene Expression Regulation MeSH
- Signal Transduction MeSH
- Tularemia genetics immunology microbiology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Imunitní systém je součástí komplexních tělních mechanizmů, zánětu, kterými člověk reaguje na expozici patogenním mikroorganizmům nebo poškození vlastních struktur. Především složky vrozené imunity jsou vybaveny receptory, kterými identifikují vzory patogenů PAMP a signály vnitřního poškození DAMP. Charakteristika zánětlivé odpovědi je určena aktuálními potřebami. Potenciál zánětlivé reakce je velký a jeho intenzita i rozsah musí být přísně regulovány na mnoha úrovních.
Immune system is the integral part of the complex body response, inflammation, which is raised either by the exposure to external signals, predominantly pathogens or by damage of own structures. Predominantly innate immunity is equiped by the receptors recognizing pathogenic PAMPs or signals of own damage DAMPs. The inflammatory response is reflecting the actual demand of our body. The potential of the inflammatory response is so powerful that its intensity and extent have to be carefully regulated on many levels.
- Keywords
- vycvičená imunita,
- MeSH
- Adaptive Immunity MeSH
- Invertebrates immunology MeSH
- Plant Immunity MeSH
- Immune System Phenomena * MeSH
- Immunologic Memory * MeSH
- Vertebrates immunology MeSH
- Pathogen-Associated Molecular Pattern Molecules MeSH
- Immunity, Innate MeSH
- Plants MeSH
- Publication type
- Review MeSH
Plant plasma membrane associated proteins play significant roles in Microbe-Associated Molecular Pattern (MAMP) mediated defence responses including signal transduction, membrane transport or energetic metabolism. To elucidate the dynamics of proteins associated with plasma membrane in response to cryptogein, a well-known MAMP of defence reaction secreted by the oomycete Phytophthora cryptogea, 2D-Blue Native/SDS gel electrophoresis of plasma membrane fractions was employed. This approach revealed 21 up- or down-regulated protein spots of which 15 were successfully identified as proteins related to transport through plasma membrane, vesicle trafficking, and metabolic enzymes including cytosolic NADP-malic enzyme and glutamine synthetase. Observed changes in proteins were also confirmed on transcriptional level by qRT-PCR analysis. In addition, a significantly decreased accumulation of transcripts observed after employment of a mutant variant of cryptogein Leu41Phe, exhibiting a conspicuous defect in induction of resistance, sustains the contribution of identified proteins in cryptogein-triggered cellular responses. Our data provide further evidence for dynamic MAMP-induced changes in plasma membrane associated proteins.
- MeSH
- Cell Membrane metabolism MeSH
- Chromatography, Liquid MeSH
- Electrophoresis, Polyacrylamide Gel MeSH
- Fungal Proteins genetics metabolism MeSH
- Membrane Proteins genetics metabolism MeSH
- Pathogen-Associated Molecular Pattern Molecules metabolism MeSH
- Phytophthora physiology MeSH
- Plant Proteins genetics metabolism MeSH
- Nicotiana genetics metabolism microbiology MeSH
- Tandem Mass Spectrometry MeSH
- Trypsin chemistry MeSH
- Publication type
- Journal Article MeSH
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- MeSH
- Acute Disease MeSH
- Antigen-Presenting Cells MeSH
- Biomarkers MeSH
- Chemokines MeSH
- Chronic Disease MeSH
- Diagnosis, Differential MeSH
- Gastrointestinal Diseases etiology MeSH
- Glucocorticoids therapeutic use MeSH
- Transplantation, Homologous * adverse effects MeSH
- Immunosuppressive Agents therapeutic use MeSH
- Skin Diseases etiology MeSH
- Humans MeSH
- Graft vs Host Disease * diagnosis etiology drug therapy physiopathology MeSH
- Liver Diseases etiology MeSH
- Pathogen-Associated Molecular Pattern Molecules MeSH
- Transplantation Conditioning adverse effects MeSH
- Gastrointestinal Microbiome MeSH
- Severity of Illness Index MeSH
- T-Lymphocytes MeSH
- Hematopoietic Stem Cell Transplantation * adverse effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Alarmins physiology immunology MeSH
- Skin Physiological Phenomena * immunology MeSH
- Interleukin-23 drug effects MeSH
- Humans MeSH
- Models, Immunological MeSH
- Models, Molecular MeSH
- Antibodies, Monoclonal pharmacology MeSH
- Pathogen-Associated Molecular Pattern Molecules immunology MeSH
- Psoriasis * drug therapy immunology physiopathology MeSH
- Tumor Necrosis Factor-alpha MeSH
- Ustekinumab * pharmacology MeSH
- Check Tag
- Humans MeSH
