Complement system and phagocytosis in a colonial protochordate

Peronato, Anna; Drago, Lorenzo; Rothbächer, Ute; Macor, Paolo; Ballarin, Loriano; Franchi, Nicola

doi:10.1016/j.dci.2019.103530

Cited by 16 publications

(7 citation statements)

References 37 publications

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“…In ascidians, which are the closest relatives to vertebrates [5,6], haemocytes are responsible for all vital activities because they are involved in nutrition [7], excretion [8], asexual reproduction [9][10][11][12][13] and part of tunic formation [14]. In defence responses [15], haemocytes are able to phagocytise foreign materials [16][17][18][19][20]; release opsonins [21], cytokines [22][23][24], agglutinins [25,26], complement factors [27,28] and antimicrobial peptides [29]; actively participate with cytotoxic substances in inflammatory reactions [30]; and are involved in allorecognition between contacting colonies that are genetically incompatible [31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Searching for the Origin and the Differentiation of Haemocytes before and after Larval Settlement of the Colonial Ascidian Botryllus schlosseri: An Ultrastructural Viewpoint

Cima

2022

JMSE

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The colonial ascidian Botryllus schlosseri possesses an innate immunity, which plays fundamental roles in its survival, adaptability, worldwide spread and ecological success. Three lines of differentiation pathways of circulating haemocytes are known to be present in the haemolymph, starting from undifferentiated haemoblasts: (i) the phagocytic line (hyaline amoebocytes and macrophage-like cells), (ii) the cytotoxic line (granular amoebocytes and morula cells) and (iii) the storage cell line (pigment cells and nephrocytes). Many questions remain about their origin, and thus, observations during various stages of development were undertaken in this study. Haemocytes were detected beginning from the early tailbud embryo stage. Haemoblasts were always present and morula cells were the first differentiated haemocytes detected. In both the next stage, just before hatching, and the swimming tadpole larva stage, hyaline amoebocytes and pigment cells were also recognisable. Some morula cells containing active phenoloxidase migrated from the haemolymph into the tunic after having crossed the epidermis, and this behaviour could be related to the preparation of a defensive function for spatial competition. During larval metamorphosis, macrophage-like cells appeared with their phagosomes positive to acid phosphatase activity and containing apoptotic cells from tail tissue degeneration. After metamorphosis, in the filter-feeding oozoid stage, nephrocytes involved in nitrogen catabolism finally appeared. In both the subendostylar sinus and the peripheral blind-sac vessels (ampullae), clusters of haemoblasts were recognisable, some of which showed incipient specialisations, considering the hypothesis of the presence of putative niches of haemolymph stem cells.

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Section: Introductionmentioning

confidence: 99%

Searching for the Origin and the Differentiation of Haemocytes before and after Larval Settlement of the Colonial Ascidian Botryllus schlosseri: An Ultrastructural Viewpoint

Cima

2022

JMSE

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“…The colonial ascidian B. schlosseri is a reliable organism for the study of tunicate innate immunity, and various humoral factors involved in the protection from foreign cells have been identified so far, including the enzyme PO [ 54 , 55 , 56 ], a rhamnose-binding lectin with opsonic properties [ 57 , 58 ] and various complement components modulating the immune responses [ 47 , 48 , 49 , 59 ].…”

Section: Discussionmentioning

confidence: 99%

Botryllin, a Novel Antimicrobial Peptide from the Colonial Ascidian Botryllus schlosseri

2023

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By mining the transcriptome of the colonial ascidian Botryllus schlosseri, we identified a transcript for a novel styelin-like antimicrobial peptide, which we named botryllin. The gene is constitutively transcribed by circulating cytotoxic morula cells (MCs) as a pre-propeptide that is then cleaved to mature peptide. The synthetic peptide, obtained from in silico translation of the transcript, shows robust killing activity of bacterial and unicellular yeast cells, causing breakages of both the plasma membrane and the cell wall. Specific monoclonal antibodies were raised against the epitopes of the putative amino acid sequence of the propeptide and the mature peptide; in both cases, they label the MC granular content. Upon MC degranulation induced by the presence of nonself, the antibodies recognise the extracellular nets with entrapped bacteria nearby MC remains. The obtained results suggest that the botryllin gene carries the information for the synthesis of an AMP involved in the protection of B. schlosseri from invading foreign cells.

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“…In Botryllus schlosseri, a model species for the study of immunobiology (Figure 5A), allorecognition and asexual reproduction, including whole-body regeneration (119,(129)(130)(131), colonies increase their size through periodical cycles of asexual reproduction requiring the involvement of stem cells. Unlike most species, where the body is long-lived and maintained by cellular replacement, B. schlosseri regenerates new colonial units (buds) on a biweekly basis from stem cells that remain for life, replacing the previous generation's zooids and, partly, the circulatory cells (129,(132)(133)(134)(135)(136)(137), Circulating immune cells influence the process as they assure the crosstalk between blastogenic generations at the generation change (takeover) (Figure 5D): cytotoxic MCs increase the transcription of the complement factor 3 (C3) and stimulate phagocytosis, required for the removal of apoptotic cells in tissues of old zooids (138,139). Phagocytes are also required for the completion of the takeover and the formation of new buds as the prevention of phagocytosis blocks the process (140).…”

Section: Ascidiansmentioning

confidence: 99%

Stem Cells and Innate Immunity in Aquatic Invertebrates: Bridging Two Seemingly Disparate Disciplines for New Discoveries in Biology

et al. 2021

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The scopes related to the interplay between stem cells and the immune system are broad and range from the basic understanding of organism’s physiology and ecology to translational studies, further contributing to (eco)toxicology, biotechnology, and medicine as well as regulatory and ethical aspects. Stem cells originate immune cells through hematopoiesis, and the interplay between the two cell types is required in processes like regeneration. In addition, stem and immune cell anomalies directly affect the organism’s functions, its ability to cope with environmental changes and, indirectly, its role in ecosystem services. However, stem cells and immune cells continue to be considered parts of two branches of biological research with few interconnections between them. This review aims to bridge these two seemingly disparate disciplines towards much more integrative and transformative approaches with examples deriving mainly from aquatic invertebrates. We discuss the current understanding of cross-disciplinary collaborative and emerging issues, raising novel hypotheses and comments. We also discuss the problems and perspectives of the two disciplines and how to integrate their conceptual frameworks to address basic equations in biology in a new, innovative way.

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Complement system and phagocytosis in a colonial protochordate

Cited by 16 publications

References 37 publications

Searching for the Origin and the Differentiation of Haemocytes before and after Larval Settlement of the Colonial Ascidian Botryllus schlosseri: An Ultrastructural Viewpoint

Searching for the Origin and the Differentiation of Haemocytes before and after Larval Settlement of the Colonial Ascidian Botryllus schlosseri: An Ultrastructural Viewpoint

Botryllin, a Novel Antimicrobial Peptide from the Colonial Ascidian Botryllus schlosseri

Stem Cells and Innate Immunity in Aquatic Invertebrates: Bridging Two Seemingly Disparate Disciplines for New Discoveries in Biology

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