Localization of vasoactive intestinal peptide and toll‐like receptor 2 immunoreactive cells in endostyle of urochordate <scp><i>Styela plicata</i></scp> (Lesueur, 1823)

Albano

Savoca

et al. 2022

Biology

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The immune system of a fish has cellular and molecular defense mechanisms that are substantially retained throughout the evolution of vertebrates. The innate immune system provides biological processes, such as phagocytosis and mechanical barriers, to implement an efficient defensive response after exposure to chemical or biological contaminants, pollutants, and contact with parasites, germs, and pathogens. Club cells (CCs) are widespread in the skin of Ostariophysi. After a predator attack or exposure to toxins and parasites, these cells can produce alarming substances. Given their effectiveness against viruses, parasites, and common skin lesions, recent studies have suggested that CCs are a component of the immune system. This study aims to immunohistochemically characterize the CCs for the first time in the skin of zebrafish, using mitogen-activated protein kinase (MAPK) p38, Toll-like receptor (TLR)2, Piscidin1, and inducible nitric oxide synthase (iNOS) peptides involved in the function of all types of vertebrate immune cells. According to our analysis, the intermediate layer of the epidermis exhibited rounded, oval, and elongated CCs, with central acidophilic cytoplasm and a spherical basophilic nucleus, that are positive to the antibodies tested. Our results may confirm that CCs could be involved in the immune function, increasing our knowledge of the immune system of teleosts.

Section: Discussionmentioning

confidence: 99%

Confocal Identification of Immune Molecules in Skin Club Cells of Zebrafish (Danio rerio, Hamilton 1882) and Their Possible Role in Immunity

Albano

Savoca

et al. 2022

Biology

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“…TLRs, found in all classes of vertebrates [ 47 , 48 , 49 ], are physically and genotypically highly conserved receptors [ 50 , 51 ] that are involved in immune response [ 52 ]. Phylogenetically, TLRs—particularly TLR-2—have been characterized in urochordates (tunica and endostyle of ascidian Styela plicata) [ 53 , 54 ], cartilaginous fishes [ 10 ], bony fishes [ 55 ], and other upper vertebrates [ 48 , 56 ]. Sharks are interesting species from an evolutionary point of view, as they are considered the first species to have evolved adaptive immune responses in addition to the innate immune system.…”

Section: Methodsmentioning

confidence: 99%

Confocal Characterization of Intestinal Dendritic Cells from Myxines to Teleosts

Capillo

Fumia

et al. 2022

Biology

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Dendritic cells (DCs) are antigen-presenting cells (APCs) that regulate the beginning of adaptive immune responses. The mechanisms of tolerance to antigens moving through the digestive tract are known to be regulated by intestinal DCs. Agnatha and Gnathostoma are descendants of a common ancestor. The Ostracoderms gave rise to Cyclostomes, whereas the Placoderms gave rise to Chondrichthyes. Sarcopterygii and Actinopterygii are two evolutionary lines of bony fishes. Brachiopterygii and Neopterygii descend from the Actinopterygii. From Neopterygii, Holostei and Teleostei evolved. Using immunohistochemistry with TLR-2, Langerin/CD207, and MHC II, this study aimed to characterize intestinal DCs, from myxines to teleosts. The findings reveal that DCs are positive for the antibodies tested, highlighting the presence of DCs and DC-like cells phylogenetically from myxines, for the first time, to teleosts. These findings may aid in improving the level of knowledge about the immune system’s evolution and these sentinel cells, which are crucial to the body’s defense.

“…RCs are peculiar cells, equipped with granules containing serotonin and piscidin [ 81 ], a potent antimicrobial peptide [ 82 , 83 , 84 ]. They act via Toll-like receptor (TLR), a type of evolutionarily conserved receptor [ 40 , 85 , 86 , 87 , 88 , 89 , 90 , 91 ] activated in response to viruses, bacteria or organic or chemical stress [ 92 , 93 , 94 , 95 , 96 , 97 ].…”

Section: Discussionmentioning

confidence: 99%

Histological and Chemical Analysis of Heavy Metals in Kidney and Gills of Boops boops: Melanomacrophages Centers and Rodlet Cells as Environmental Biomarkers

Cicero

Fumia

et al. 2022

Toxics

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Industrialization has resulted in a massive increase in garbage output, which is frequently discharged or stored in waterways like rivers and seas. Due to their toxicity, durability, bioaccumulation, and biomagnification, heavy metals (such as mercury, cadmium, and lead) have been identified as strong biological poisons. Their presence in the aquatic environment has the potential to affect water quality parameters and aquatic life in general. Teleosts’ histopathology provides a sensitive indicator of pollutant-induced stress, because their organs have a central role in the transformation of different active chemical compounds in the aquatic environment. In particular, the gills, kidneys, and liver are placed at the center of toxicological studies. The purpose of this study is to examine the morphological changes caused by heavy metals in the kidney and gills of Boops boops, with a focus on melanomacrophages centers (MMCs) and rodlet cells (RCs) as environmental biomarkers, using histological and histochemical stainings (hematoxylin/eosin, Van Gieson trichrome, Periodic Acid Schiff reaction, and Alcian Blue/PAS 2.5), and immunoperoxidase methods. Our findings show an increase of MMCs and RCs linked to higher exposure to heavy metals, confirming the role of these aggregates and cells as reliable biomarkers of potential aquatic environmental changes reflected in fish fauna. The cytological study of RCs and MMCs could be important in gaining a better understanding of the complicated immune systems of teleosts.