Echinoderm Antimicrobial Peptides

Arizza, Vincenzo; Schillaci, Domenico

doi:10.1016/b978-0-12-803252-7.00012-6

Cited by 4 publications

(3 citation statements)

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“…Further studies have shown that the echinoderm phagocytes produce reactive oxygen radicals, haemolysin, agglutinins, phenoloxidase and antimicrobial peptides. 53,54 Echinoderm genomes investigated show a richness of receptors making this group of animals well suited for recognition of foreign material. Thus, the sea urchin Strongylocentrotus purpuratus carry at least 221 TLR genes, Mesocentrotus franciscanus possess 276 TLR genes and S. fragilis 238 TLR genes.…”

Section: Echinodermsmentioning

confidence: 99%

“…It had previously been observed that leukocytes could perform phagocytosis but the cellular interactions in these invertebrates, resembling inflammation in vertebrates, were found surprising. Further studies have shown that the echinoderm phagocytes produce reactive oxygen radicals, haemolysin, agglutinins, phenoloxidase and antimicrobial peptides 53,54 . Echinoderm genomes investigated show a richness of receptors making this group of animals well suited for recognition of foreign material.…”

Section: Origin and Evolutionmentioning

confidence: 99%

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Neutrophils and aquatic pathogens

Buchmann

2022

Parasite Immunology

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Introduction Neutrophilic granulocytes are short‐lived cells continuously circulating in the vascular system of vertebrates. They play a basic and decisive role in the innate immune defence of the hosts against all types of pathogenic microorganisms. Methods Based on a literature study, the functions of neutrophils and cells with similar functions are described. The study places special emphasis on organisms in the aquatic environment and the pathogens occurring in that particular environment. Results The evolutionary origin of this specific cell type is not clear, but its most basic traits (recognition of foreign elements, extracellular trap release, phagocytosis and elimination of ingested material) are found in phagocytes in members of evolutionary ancient invertebrate groups spanning from amoebae, sponges, sea‐anemones, mollusks (snails and mussels), arthropods (crustaceans and insects) to echinoderms (sea stars and sea urchins). Their functions as innate immune sentinels and effector cells in these groups are well described. Neutrophilic granulocytes with elongated and lobed nuclei (possibly allowing cell movements through narrow extracellular spaces and leaving space for phagosomes) occur in vertebrates including fish, amphibians, reptiles, birds and mammals although the morphology of the nucleus, stainability of cytoplasmic granula, and the antimicrobial armament vary among groups. Following the pathogen invasion of a fish host, the neutrophils migrates from the vascular system into the infection focus. They apply their PRRs (including TLRs) to recognize the invader as non‐self, produce netosis by casting extracellular chromatin containing traps in the microenvironment. These nets assist the immobilization of invading microbes and prevents their further spread. The cells attach to and engulf the microbes by phagocytosis, whereafter they eliminate the pathogen in phagolysosomes equipped with a range of killing mechanisms and attract, by release of chemokines, additional immune cells (monocytes, macrophages and lymphocytes) to the site of invasion. Their role in innate immunity of fish hosts towards aquatic pathogens has been elucidated by in vivo and in vitro studies. Neutrophils interact with virus (e.g. IPNV and VHSV), bacteria (e.g. Aeromonas, Vibrio, Edwardsiella, Mycobacterium and Renibacterium) and parasites, including monogeneans (Gyrodactylus), cestodes (Diphyllobothrium), trematodes (Diplostomum) and ciliates (Ichthyophthirius and Philasterides). Despite the decisive function of neutrophils in innate immunity and early protection, the excessive production of ROS, RNS and NETs may lead to pathological disturbances in the host, which are exacerbated if the pathogens evolve immune evasion mechanisms. Conclusion Neutrophils in aquatic organisms play a central role in innate immunity but may serve as a toll and a support in acquired protection. The strong impact of the cellular reactions not only on pathogen but also on host tissues emphasizes that an optimal immune reaction is balanced, involv...

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Section: Echinodermsmentioning

confidence: 99%

Section: Origin and Evolutionmentioning

confidence: 99%

Neutrophils and aquatic pathogens

Buchmann

2022

Parasite Immunology

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“…In response to PRR signaling, organisms secrete a wide variety of effector proteins that include expanded gene families encoding anti-microbial peptides and proteins (AMPs) ( 14 – 17 ). Invertebrates such as sea urchins have a sophisticated innate immune system with expanded gene families encoding TLRs, NLRs [( 18 , 19 ); reviewed in ( 20 , 21 )], small C-type lectins ( 19 ), and a variety of AMPs that function in a wide range of organisms ( 16 , 22 , 23 ). The purple sea urchin from the Pacific coast of North America, Strongylocentrotus purpuratus , also has the SpTransformer ( SpTrf ) gene family [reviewed in ( 24 )] that encodes unique immune effector proteins.…”

Section: Introductionmentioning

confidence: 99%

Recombinant SpTransformer proteins are functionally diverse for binding and phagocytosis by three subtypes of sea urchin phagocytes

Crow,

Shaw,

Grayfer

et al. 2024

Front. Immunol.

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IntroductionThe California purple sea urchin, Strongylocentrotus purpuratus, relies solely on an innate immune system to combat the many pathogens in the marine environment. One aspect of their molecular defenses is the SpTransformer (SpTrf) gene family that is upregulated in response to immune challenge. The gene sequences are highly variable both within and among animals and likely encode thousands of SpTrf isoforms within the sea urchin population. The native SpTrf proteins bind foreign targets and augment phagocytosis of a marine Vibrio. A recombinant (r)SpTrf-E1-Ec protein produced by E. coli also binds Vibrio but does not augment phagocytosis.MethodsTo address the question of whether other rSpTrf isoforms function as opsonins and augment phagocytosis, six rSpTrf proteins were expressed in insect cells. ResultsThe rSpTrf proteins are larger than expected, are glycosylated, and one dimerized irreversibly. Each rSpTrf protein cross-linked to inert magnetic beads (rSpTrf::beads) results in different levels of surface binding and phagocytosis by phagocytes. Initial analysis shows that significantly more rSpTrf::beads associate with cells compared to control BSA::beads. Binding specificity was verified by pre-incubating the rSpTrf::beads with antibodies, which reduces the association with phagocytes. The different rSpTrf::beads show significant differences for cell surface binding and phagocytosis by phagocytes. Furthermore, there are differences among the three distinct types of phagocytes that show specific vs. constitutive binding and phagocytosis. ConclusionThese findings illustrate the complexity and effectiveness of the sea urchin innate immune system driven by the natSpTrf proteins and the phagocyte cell populations that act to neutralize a wide range of foreign pathogens.

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