scholarly journals Fasciola hepatica hijacks host macrophage miRNA machinery to modulate early innate immune responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nham Tran ◽  
Alison Ricafrente ◽  
Joyce To ◽  
Maria Lund ◽  
Tania M. Marques ◽  
...  
Keyword(s):  
Immune Responses ◽  
Cell Function ◽  
Fasciola Hepatica ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Defence Mechanisms ◽  
First Line ◽  
M1 Macrophages ◽  
Successful Infection ◽  
Inflammatory Immune Response

AbstractFasciola hepatica, a global worm parasite of humans and their livestock, regulates host innate immune responses within hours of infection. Host macrophages, essential to the first-line defence mechanisms, are quickly restricted in their ability to initiate a classic protective pro-inflammatory immune response. We found that macrophages from infected animals are enriched with parasite-derived micro(mi)RNAs. The most abundant of these miRNAs, fhe-miR-125b, is released by the parasite via exosomes and is homologous to a mammalian miRNA, hsa-miR-125b, that is known to regulate the activation of pro-inflammatory M1 macrophages. We show that the parasite fhe-miR-125b loads onto the mammalian Argonaut protein (Ago-2) within macrophages during infection and, therefore, propose that it mimics host miR-125b to negatively regulate the production of inflammatory cytokines. The hijacking of the miRNA machinery controlling innate cell function could be a fundamental mechanism by which worm parasites disarm the early immune responses of their host to ensure successful infection.

PRRs in pathogen recognition

2006 ◽  
Vol 1 (3) ◽  
pp. 299-313 ◽  
Author(s):  
Satoshi Uematsu ◽  
Shizuo Akira
Keyword(s):  
Pattern Recognition ◽  
Immune Responses ◽  
Pattern Recognition Receptors ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Pathogen Recognition ◽  
First Line ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
Wide Range

AbstractThe innate immune system provides the first line of host defense against invading microorganisms before the development of adaptive immune responses. Innate immune responses are initiated by germline-encoded pattern recognition receptors (PRRs), which recognize specific structures of microorganisms. Toll-like receptors (TLRs) are pattern-recognition receptors that sense a wide range of microorganisms, including bacteria, fungi, protozoa and viruses. TLRs exist either on the cell surface or in the lysosome/endosome compartment and induce innate immune responses. Recently, cytoplasmic PRRs have been identified which detect pathogens that have invaded the cytosol. This review focuses on the pathogen recognition of PRRs in innate immunity.

scholarly journals Two arms are better than one: parasite variation leads to combined inducible and constitutive innate immune responses

2008 ◽  
Vol 275 (1637) ◽  
pp. 937-945 ◽  
Author(s):  
Ruth Hamilton ◽  
Mike Siva-Jothy ◽  
Mike Boots
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
A Priori ◽  
Innate Immune ◽  
Induced Responses ◽  
Innate Immune Responses ◽  
Defence Mechanisms ◽  
Induced Defences ◽  
Differential Costs ◽  
Better Than

Parasites represent a major threat to all organisms which has led to the evolution of an array of complex and effective defence mechanisms. Common to both vertebrates and invertebrates are innate immune mechanisms that can be either constitutively expressed or induced on exposure to infection. In nature, we find that a combination of both induced and constitutive responses are employed by vertebrates, invertebrates and, to an extent, plants when they are exposed to a parasite. Here we use a simple within-host model motivated by the insect immune system, consisting of both constitutive and induced responses, to address the question of why both types of response are maintained so ubiquitously. Generally, induced responses are thought to be advantageous because they are only used when required but are too costly to maintain constantly, while constitutive responses are advantageous because they are always ready to act. However, using a simple cost function but with no a priori assumptions about relative costs, we show that variability in parasite growth rates selects for a strategy that combines both constitutive and induced defences. Differential costs are therefore not necessary to explain the adoption of both forms of defence. Clearly, hosts are likely to be challenged by variable parasites in nature and this is sufficient to explain why it is optimal to deploy both arms of the innate immune system.

scholarly journals lncRNAs Regulate Innate Immune Responses and Their Roles in Macrophage Polarization

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhen Wang ◽  
Ying Zheng
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
Innate Immune System ◽  
Macrophage Polarization ◽  
Noncoding Rnas ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Innate Immune Responses ◽  
First Line ◽  
New Class

The innate immune system is the first line of defense against microbial pathogens. The activated innate immune system plays important roles in eliciting antimicrobial defenses. Despite the benefits of innate immune responses, excessive inflammation will cause host damage. Thus, tight regulation of these processes is required for the maintenance of immune homeostasis. Recently, a new class of long noncoding RNAs (lncRNAs) has emerged as important regulators in many physiological and pathological processes. Dysregulated lncRNAs have been found to be associated with excessive or uncontrolled inflammation. In this brief review, we summarize the roles of functional lncRNAs in regulating innate immune responses. We also discuss the roles of lncRNAs in macrophage polarization, an important molecular event in the innate immune responses.

scholarly journals An Evaluation of the Fasciola hepatica miRnome Predicts a Targeted Regulation of Mammalian Innate Immune Responses

2021 ◽  
Vol 11 ◽  
Author(s):  
Alison Ricafrente ◽  
Hieu Nguyen ◽  
Nham Tran ◽  
Sheila Donnelly
Keyword(s):  
Immune Responses ◽  
Immune Cell ◽  
Fasciola Hepatica ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Regulate Gene Expression ◽  
Non Coding Rnas ◽  
Parasitic Worms ◽  
High Degree ◽  
Insight Into

Understanding mechanisms by which parasitic worms (helminths) control their hosts’ immune responses is critical to the development of effective new disease interventions. Fasciola hepatica, a global scourge of humans and their livestock, suppresses host innate immune responses within hours of infection, ensuring that host protective responses are quickly incapacitated. This allows the parasite to freely migrate from the intestine, through the liver to ultimately reside in the bile duct, where the parasite establishes a chronic infection that is largely tolerated by the host. The recent identification of micro(mi)RNA, small RNAs that regulate gene expression, within the extracellular vesicles secreted by helminths suggest that these non-coding RNAs may have a role in the parasite-host interplay. To date, 77 miRNAs have been identified in F. hepatica comprising primarily of ancient conserved species of miRNAs. We hypothesized that many of these miRNAs are utilized by the parasite to regulate host immune signaling pathways. To test this theory, we first compiled all of the known published F. hepatica miRNAs and critically curated their sequences and annotations. Then with a focus on the miRNAs expressed by the juvenile worms, we predicted gene targets within human innate immune cells. This approach revealed the existence of targets within every immune cell, providing evidence for the universal management of host immunology by this parasite. Notably, there was a high degree of redundancy in the potential for the parasite to regulate the activation of dendritic cells, eosinophils and neutrophils, with multiple miRNAs predicted to act on singular gene targets within these cells. This original exploration of the Fasciola miRnome offers the first molecular insight into mechanisms by which F. hepatica can regulate the host protective immune response.

scholarly journals The First Line of Defense: Receptor-like Protein Kinase-Mediated Stomatal Immunity

2021 ◽  
Vol 23 (1) ◽  
pp. 343
Author(s):  
Zhe Wang ◽  
Xiaoping Gou
Keyword(s):  
Immune Responses ◽  
Water Exchange ◽  
Guard Cells ◽  
Innate Immune ◽  
Research Progress ◽  
Future Research ◽  
Bacterial Invasion ◽  
Innate Immune Responses ◽  
First Line ◽  
Molecular Patterns

Stomata regulate gas and water exchange between the plant and external atmosphere, which are vital for photosynthesis and transpiration. Stomata are also the natural entrance for pathogens invading into the apoplast. Therefore, stomata play an important role in plants against pathogens. The pattern recognition receptors (PRRs) locate in guard cells to perceive pathogen/microbe-associated molecular patterns (PAMPs) and trigger a series of plant innate immune responses, including rapid closure of stomata to limit bacterial invasion, which is termed stomatal immunity. Many PRRs involved in stomatal immunity are plasma membrane-located receptor-like protein kinases (RLKs). This review focuses on the current research progress of RLK-mediated signaling pathways involved in stomatal immunity, and discusses questions that need to be addressed in future research.

scholarly journals Toll-like Receptor (TLR) dan Imunitas Natura

2018 ◽  
Vol 15 (3) ◽  
pp. 111
Author(s):  
Suprapto Ma’at
Keyword(s):  
Immune Responses ◽  
Innate Immune ◽  
Acquired Immunity ◽  
Gene Products ◽  
Innate Immune Responses ◽  
Toll Like Receptor ◽  
First Line ◽  
Expression Of Genes ◽  
Molecular Pattern ◽  
Living Species

In all living species, the first line of defence against microbial aggressions is constituted by innate immunity. Toll-like receptors(TLRs) are a family of pattern recognition receptors that are activated by specific components of microbes and certain host molecules.They constitute the first line of defense against many pathogens and play a crucial role in the function of the innate immune system.Recognition of pathogen-associated molecular pattern (PAMP) by TLR, alone or heterodimerization with other TLR or non-TLR receptors,induces signals responsible for the activation of genes important for an effective host defense, especially proinflammatory cytokines, orinitiates signal transduction pathways, which trigger expression of genes. These gene products control innate immune responses andfurther instruct development of antigen-specific acquired immunity.

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