| 1. |
- Cinege, Gyöngyi, et al.
(författare)
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Broad Ultrastructural and Transcriptomic Changes Underlie the Multinucleated Giant Hemocyte Mediated Innate Immune Response against Parasitoids
- 2022
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Ingår i: Journal of Innate Immunity. - : S. Karger. - 1662-811X .- 1662-8128. ; 14:4, s. 335-354
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Tidskriftsartikel (refereegranskat)abstract
- Multinucleated giant hemocytes (MGHs) represent a novel type of blood cell in insects that participate in a highly efficient immune response against parasitoid wasps involving isolation and killing of the parasite. Previously, we showed that circulating MGHs have high motility and the interaction with the parasitoid rapidly triggers encapsulation. However, structural and molecular mechanisms behind these processes remained elusive. Here, we used detailed ultrastructural analysis and live cell imaging of MGHs to study encapsulation in Drosophila ananassae after parasitoid wasp infection. We found dynamic structural changes, mainly driven by the formation of diverse vesicular systems and newly developed complex intracytoplasmic membrane structures, and abundant generation of giant cell exosomes in MGHs. In addition, we used RNA sequencing to study the transcriptomic profile of MGHs and activated plasmatocytes 72 h after infection, as well as the uninduced blood cells. This revealed that differentiation of MGHs was accompanied by broad changes in gene expression. Consistent with the observed structural changes, transcripts related to vesicular function, cytoskeletal organization, and adhesion were enriched in MGHs. In addition, several orphan genes encoding for hemolysin-like proteins, pore-forming toxins of prokaryotic origin, were expressed at high level, which may be important for parasitoid elimination. Our results reveal coordinated molecular and structural changes in the course of MGH differentiation and parasitoid encapsulation, providing a mechanistic model for a powerful innate immune response.
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| 2. |
- Gabor, Erika, et al.
(författare)
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Identification of reference markers for characterizing honey bee (Apis mellifera) hemocyte classes
- 2020
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 109
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Tidskriftsartikel (refereegranskat)abstract
- Cell mediated immunity of the honey bee (Apis mellifera) involves the activity of several hemocyte populations, currently defined by morphological features and lectin binding characteristics. The objective of the present study was to identify molecular markers capable of characterizing subsets of honey bee hemocytes. We developed and employed monoclonal antibodies with restricted reactions to functionally distinct hemocyte subpopulations. Melanizing cells, known as oenocytoids, were defined by an antibody to prophenoloxidase, aggregating cells were identified by the expression of Hemolectin, and phagocytic cells were identified by a marker expressed on granulocytes. We anticipate that this combination of antibodies not only allows for the detection of functionally distinct hemocyte subtypes, but will help to further the exploration of hematopoietic compartments, as well as reveal details of the honey bee cellular immune defense against parasites and microbes.
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| 3. |
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| 4. |
- Kari, Beata, et al.
(författare)
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The raspberry Gene Is Involved in the Regulation of the Cellular Immune Response in Drosophila melanogaster
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Drosophila is an extremely useful model organism for understanding how innate immune mechanisms defend against microbes and parasitoids. Large foreign objects trigger a potent cellular immune response in Drosophila larva. In the case of endoparasitoid wasp eggs, this response includes hemocyte proliferation, lamellocyte differentiation and eventual encapsulation of the egg. The encapsulation reaction involves the attachment and spreading of hemocytes around the egg, which requires cytoskeletal rearrangements, changes in adhesion properties and cell shape, as well as melanization of the capsule. Guanine nucleotide metabolism has an essential role in the regulation of pathways necessary for this encapsulation response. Here, we show that the Drosophila inosine 5'-monophosphate dehydrogenase (IMPDH), encoded by raspberry (ras), is centrally important for a proper cellular immune response against eggs from the parasitoid wasp Leptopilina boulardi. Notably, hemocyte attachment to the egg and subsequent melanization of the capsule are deficient in hypomorphic ras mutant larvae, which results in a compromised cellular immune response and increased survival of the parasitoid.
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| 5. |
- Kurucz, Eva, et al.
(författare)
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Definition of Drosophila hemocyte subsets by cell-type specific antigens.
- 2007
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Ingår i: Acta Biol Hung. - 0236-5383. ; 58 Suppl, s. 95-111
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the heterogeneity of Drosophila hemocytes on the basis of the expression of cell-type specific antigens. The antigens characterize distinct subsets which partially overlap with those defined by morphological criteria. On the basis of the expression or the lack of expression of blood cell antigens the following hemocyte populations have been defined: crystal cells, plasmatocytes, lamellocytes and precursor cells. The expression of the antigens and thus the different cell types are developmentally regulated. The hemocytes are arranged in four main compartments: the circulating blood cells, the sessile tissue, the lymph glands and the posterior hematopoietic tissue. Each hemocyte compartment has a specific and characteristic composition of the various cell types. The described markers represent the first successful attempt to define hemocyte lineages by immunological markers in Drosophila and help to define morphologically, functionally, spatially and developmentally distinct subsets of hemocytes.
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| 6. |
- Kurucz, Eva, et al.
(författare)
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Hemese, a hemocyte-specific transmembrane protein, affects the cellular immune response in Drosophila.
- 2003
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 100:5, s. 2622-7
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Tidskriftsartikel (refereegranskat)abstract
- We have identified a previously undescribed transmembrane protein, Hemese, from Drosophila melanogaster blood cells (hemocytes), by using a monoclonal pan-hemocyte antibody. Heavy glycosylation is suggested by the heterogeneous size distribution, ranging between 37 and 70 kDa. Hemese expression is restricted to the cell surfaces of hemocytes of all classes, and to the hematopoietic organs. The sequence of the corresponding gene, Hemese (He), predicts a glycophorin-like protein of 15 kDa, excluding an N-terminal signal peptide, with a single hydrophobic transmembrane region. The extracellular region consists mainly of Ser/Thr-rich sequence of low complexity, with several potential O-glycosylation sites. Hemese contains phosphotyrosine and the cytoplasmic region has potential phosphorylation sites, suggesting an involvement in signal transduction. Depletion of Hemese by RNA interference has no obvious effect under normal conditions, but the cellular response to parasitic wasps is much enhanced. This finding indicates that Hemese plays a modulatory role in the activation or recruitment of the hemocytes.
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| 7. |
- Kurucz, Eva, et al.
(författare)
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Nimrod, a putative phagocytosis receptor with EGF repeats in Drosophila plasmatocytes.
- 2007
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Ingår i: Curr Biol. - 0960-9822. ; 17:7, s. 649-54
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Tidskriftsartikel (refereegranskat)abstract
- The hemocytes, the blood cells of Drosophila, participate in the humoral and cellular immune defense reactions against microbes and parasites [1-8]. The plasmatocytes, one class of hemocytes, are phagocytically active and play an important role in immunity and development by removing microorganisms as well as apoptotic cells. On the surface of circulating and sessile plasmatocytes, we have now identified a protein, Nimrod C1 (NimC1), which is involved in the phagocytosis of bacteria. Suppression of NimC1 expression in plasmatocytes inhibited the phagocytosis of Staphylococcus aureus. Conversely, overexpression of NimC1 in S2 cells stimulated the phagocytosis of both S. aureus and Escherichia coli. NimC1 is a 90-100 kDa single-pass transmembrane protein with ten characteristic EGF-like repeats (NIM repeats). The nimC1 gene is part of a cluster of ten related nimrod genes at 34E on chromosome 2, and similar clusters of nimrod-like genes are conserved in other insects such as Anopheles and Apis. The Nimrod proteins are related to other putative phagocytosis receptors such as Eater and Draper from D. melanogaster and CED-1 from C. elegans. Together, they form a superfamily that also includes proteins that are encoded in the human genome.
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| 8. |
- Márkus, Róbert, et al.
(författare)
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Sessile hemocytes as a hematopoietic compartment in Drosophila melanogaster
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:12, s. 4805-4809
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Tidskriftsartikel (refereegranskat)abstract
- The blood cells, or hemocytes, in Drosophila participate in the immune response through the production of antimicrobial peptides, the phagocytosis of bacteria, and the encapsulation of larger foreign particles such as parasitic eggs; these immune reactions are mediated by phylogenetically conserved mechanisms. The encapsulation reaction is analogous to the formation of granuloma in vertebrates, and is mediated by large specialized cells, the lamellocytes. The origin of the lamellocytes has not been formally established, although it has been suggested that they are derived from the lymph gland, which is generally considered to be the main hematopoietic organ in the Drosophila larva. However, it was recently observed that a subepidermal population of sessile blood cells is released into the circulation in response to a parasitoid wasp infection. We set out to analyze this phenomenon systematically. As a result, we define the sessile hemocytes as a novel hematopoietic compartment, and the main source of lamellocytes.
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| 9. |
- Rus, Florentina, et al.
(författare)
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Expression pattern of Filamin-240 in Drosophila blood cells.
- 2006
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Ingår i: Gene Expr Patterns. - 1567-133X. ; 6:8, s. 928-34
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Tidskriftsartikel (refereegranskat)abstract
- The expression pattern of Filamin-240 was studied in subsets of Drosophila blood cells by means of immunofluorescent staining and Western blot analysis with use of an antibody specific to a "filamin-folding domain", a consensus motif profile generated from the 20 existing filamin repeats. Expression of Filamin-240 is restricted to lamellocytes - a special blood cell type of the cellular immune response - and is involved in the regulation of lamellocyte development. In the cher1 homozygous larvae, which lack Filamin-240 protein, a vigorous lamellocyte differentiation occurs which is further enhanced upon in vivo immune challenge by a parasitic wasp, Leptopilina boulardi. By introducing a full-length transgene encoding the Drosophila Filamin-240 protein into the cher1 Filamin-deficient homozygous mutant, the mutant blood cell phenotype was rescued. These data demonstrate that the expression of Filamin-240 is strictly lamellocyte specific in Drosophila blood cells and that the protein is a suppressor of lamellocyte development.
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| 10. |
- Somogyi, Kálmán, et al.
(författare)
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Evolution of genes and repeats in the Nimrod superfamily.
- 2008
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Ingår i: Mol Biol Evol. - 1537-1719. ; 25:11, s. 2337-47
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Tidskriftsartikel (refereegranskat)abstract
- The recently identified Nimrod superfamily is characterized by the presence of a special type of EGF repeat, the NIM repeat, located right after a typical CCXGY/W amino acid motif. On the basis of structural features, nimrod genes can be divided into three types. The proteins encoded by Draper-type genes have an EMI domain at the N-terminal part and only one copy of the NIM motif, followed by a variable number of EGF-like repeats. The products of Nimrod B-type and Nimrod C-type genes (including the eater gene) have different kinds of N-terminal domains, and lack EGF-like repeats but contain a variable number of NIM repeats. Draper and Nimrod C-type (but not Nimrod B-type) proteins carry a transmembrane domain. Several members of the superfamily were claimed to function as receptors in phagocytosis and/or binding of bacteria, which indicates an important role in the cellular immunity and the elimination of apoptotic cells. In this paper, the evolution of the Nimrod superfamily is studied with various methods on the level of genes and repeats. A hypothesis is presented in which the NIM repeat, along with the EMI domain, emerged by structural reorganizations at the end of an EGF-like repeat chain, suggesting a mechanism for the formation of novel types of repeats. The analyses revealed diverse evolutionary patterns in the sequences containing multiple NIM repeats. Although in the Nimrod B and Nimrod C proteins show characteristics of independent evolution, many internal NIM repeats in Eater sequences seem to have undergone concerted evolution. An analysis of the nimrod genes has been performed using phylogenetic and other methods and an evolutionary scenario of the origin and diversification of the Nimrod superfamily is proposed. Our study presents an intriguing example how the evolution of multigene families may contribute to the complexity of the innate immune response.
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| 11. |
- Vilmos, Péter, et al.
(författare)
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A rapid rosetting method for separation of hemocyte sub-populations of Drosophila melanogaster.
- 2004
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Ingår i: Dev Comp Immunol. - 0145-305X. ; 28:6, s. 555-63
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Tidskriftsartikel (refereegranskat)abstract
- Hemocytes, cellular elements of the innate immune system in insects, play a crucial role in the cellular and humoral immune response. Although a significant amount of information has been collected on their differentiation and function, our understanding of hemocyte development is far from complete. Their characterisation is mostly based on morphological criteria. However, molecular markers were recently identified, defining functional subsets by the aid of monoclonal antibodies. Isolated subsets of hemocytes, in sufficient quantity and purity could help to analyse their development in vitro and also to further define their molecular characteristics. Here we describe an antibody-based rosetting technique for the physical separation of Drosophila hemocyte sub-populations. We have applied anti-hemocyte antibodies coupled to sheep red blood cells for separation. The method relies on the formation of rosettes between hemocytes and sheep erythrocytes, sensitised with discriminative anti-hemocyte monoclonal antibodies. Using this method the rosetting and non-rosetting hemocytes can be separated from each other by gradient centrifugation. Rosette-forming cells from the pellet and non-rosetting cells from the interface can be isolated in high recovery. The method can be used for functional and molecular characterisation of hemocyte sub-populations. The procedure is sensitive, reproducible and easy to perform.
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| 12. |
- Zettervall, Carl-Johan, et al.
(författare)
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A directed screen for genes involved in Drosophila blood cell activation
- 2004
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Washington : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 101:39, s. 14192-14197
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Tidskriftsartikel (refereegranskat)abstract
- An attack by a parasitic wasp activates a vigorous cellular immune response in Drosophila larvae. This response is manifested by an increased number of circulating cells, the hemocytes, and by the appearance of a specialized class of hemocyte, the lamellocytes, which participate in the encapsulation and killing of the parasite. To study the molecular mechanisms of this response, we have overexpressed different genes in the hemocytes, by using the GAL4-upstream activating sequence system and a hemocyte-specific Hemese-GAL4 driver. Multiple transgenes were tested, representing several important signaling pathways. We found that the proliferation response and the activation of lamellocyte formation are independent phenomena. A drastic increase in the number of circulating hemocytes is caused by receptor tyrosine kinases, such as Egfr, Pvr, and Alk, as well as by the downstream signaling components Ras85D and pointed, supporting the notion that the Ras-mitogen-activated protein kinase pathway regulates hemocyte numbers. In the case of Pvr and Alk, this phenotype also is accompanied by lamellocyte formation. By contrast, constitutively active hopscotch and hemipterous give massive activation of lamellocyte formation with little or no increase in total hemocyte numbers. This finding indicates that both the Jak/Stat and the Jun kinase pathways affect lamellocyte formation. Still other signals, mediated by aop(ACT), Toll(10b), and Rac1 expression, cause a simultaneous increase in lamellocyte and total cell numbers, and the same effect is seen when WNT signaling is suppressed. We conclude that the activation of a cellular response is complex and affected by multiple signaling pathways.
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