| 1. |
- Lin, Xionghui, 1976-, et al.
(författare)
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Ancient Cytokines, the Role of Astakines as Hematopoietic Growth Factors
- 2010
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:37, s. 28577-28586
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoiesis is the process by which hemocytes mature and subsequently enter the circulation. Vertebrate prokineticins (PKs) are known to take part in this process, as are the invertebrate prokineticin domain proteins, astakines. In Pacifastacus leniusculus, astakine 1 is essential for the release of new hemocytes into the open circulatory system of these animals. In addition to astakine 1, we have now cloned a homologue of astakine 1 with an insert of 13 amino acids, named as astakine 2. Both crustacean astakines lack the N-terminal AVIT motif, which is present in vertebrate PKs, and hence receptor binding differs from that of vertebrate PKs. We have found astakine-like sequences in 19 different invertebrate species, and the sequences show that some motifs are conserved among invertebrate groups. Previously we showed that astakine 1 is directly involved in hematopoiesis, and now we show that astakine 1 and astakine 2 have different roles in hemocyte lineage differentiation. Astakine 1 can stimulate proliferation of hematopoietic tissue (Hpt) cells (precursor of hemocytes) as well as specifically induce differentiation of Hpt cells along the semigranular cell lineage, whereas astakine 2 plays a role in granular cell differentiation. Moreover, we discuss the impact of the putative structures of different astakines in comparison with the vertebrate prokineticins.
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| 2. |
- Lin, Xionghui, et al.
(författare)
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Crustacean hematopoiesis and the astakine cytokines
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 117:24, s. 6417-6424
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Forskningsöversikt (refereegranskat)abstract
- Major contributions to research in hematopoiesis in invertebrate animals have come from studies in the fruit fly, Drosophila melanogaster, and the freshwater crayfish, Pacifastacus leniusculus. These animals lack oxygen-carrying erythrocytes and blood cells of the lymphoid lineage, which participate in adaptive immune defence, thus making them suitable model animals to study the regulation of blood cells of the innate immune system. This review presents an overview of crustacean blood cell formation, the role of these cells in innate immunity and how their synthesis is regulated by the astakine cytokines. Astakines are among the first invertebrate cytokines shown to be involved in hematopoiesis, and they can stimulate the proliferation, differentiation and survival of hematopoietic tissue cells. The astakines and their vertebrate homologues, prokineticins, share similar functions in hematopoiesis; thus, studies of astakine-induced hematopoiesis in crustaceans may not only advance our understanding of the regulation of invertebrate hematopoiesis but may also provide new evolutionary perspectives about this process.
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| 3. |
- Lin, Xionghui, 1976-, et al.
(författare)
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EVOLUTION OF HEMATOPOIESIS: AN ASTAKINE INDUCED NOVEL HEMATOPOIETIC FACTOR
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We report here the cloning and initial characterization of a novel invertebrate hematopoietic factor. This factor was identified from the SSH library with the aim to find the downstream genes of an invertebrate cytokine, astakine 1 in the freshwater crayfish Pacifastacus leniusculus. This Pacifastacus Hematopoietic Factor (PHF) was found to be induced in the primary cell culture of crayfish Hpt cells (precursor of crayfish blood cells) by treatment with astakine 1. Silencing PHF did not affect the renewal of Hpt cells in vitro, but induced the apoptosis rate of Hpt cells. PHF is dominantly present in the blood lineage of crayfish (Hpt cells and blood cells), and in vivo RNAi experiment shows that knockdown of this gene results in severe loss of blood cells in the animal. Our data suggest that crayfish PHF is critical for the survival of not only hemocytes but also the Hpt cells by preventing their apoptosis, thus it plays an important role in the hematopoiesis in crayfish. PHF is a small cysteine rich protein (ca. 9 kDa) with high similarity with the N-terminal region of vertebrate CRIM1 and both of them contains an IGFBP variant motif with unknown function. Our study of PHF may also shed light on the function of this untypical IGFBP motif located in the N-terminal of vertebrate CRIM1.
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| 4. |
- Lin, Xionghui, 1976-
(författare)
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Hematopoiesis in a Crustacean
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hemocytes (blood cells) play an important role in the immune response in invertebrates, and thus the regulation of hemocyte homeostasis (hematopoiesis) is essential for the host survival against pathogens. Astakine 1, a homologue to vertebrate prokineticins, was first identified in the freshwater crayfish Pacifastacus leniusculus as a cytokine, and was found to be necessary for new hemocyte synthesis and release in vivo, and also to induce spreading and proliferation of Hematopoietic tissue cells (Hpt cells, precursor of hemocytes) in vitro. The work of this thesis is aimed to further our understanding of the molecular mechanisms involved in astakine 1 induced hematopoiesis.Crayfish transglutaminase (Tgase) has been identified in the hemocytes, and is essential for the coagulation reaction. Interestingly this enzyme is exceedingly abundant in the Hpt cells, and the spreading of Hpt cells induced by astakine 1 was accompanied by sequential loss of TGase activity from the surface of these cells. This loss of TGase activity may be an important effect of astakine 1, resulting in recruiting new hemocytes into the circulatory system. Although astakine 1 contain a prokineticin domain, it lacks the conserved N-terminal AVIT motif present in its vertebrate homologues. This motif is important for vertebrate prokineticins to interact with their receptors, indicating a different receptor interaction for crayfish astakine 1. Astakine 1 was indeed found to interact with a completely different receptor, the β-subunit of ATP synthase, on a portion of Hpt cells, and subsequently block its extracellular ATP formation. Surface ATP synthase has been reported on numerous mammalian cells, but now for the first time in an invertebrate. The activity of ATP synthase on the Hpt cells may be important for the survival and proliferation of Hpt cells, but the underlying mechanisms remain further study. With the finding of a second type of astakine in crayfish, invertebrate astakines can be divided into two groups: astakine 1 and astakine 2. The properties of astakine 2 are different from those of astakine 1 both in structure and function. In primary cell culture of Hpt cells, only astakine 1 can promote proliferation as well as differentiation into semigranular cells, whereas astakine 2 may play a potential role in the maturation of granular cells. Moreover, a novel cysteine rich protein, Pacifastacus hematopoiesis factor (PHF), was found to be one target gene of astakine 1 in Hpt cells. Down regulation of PHF results in increased apoptosis in Hpt cells in vitro, and in vivo silencing PHF leads to a severe loss of hemocytes in the animal. Therefore astakine 1 acquires the anti-apoptosis ability by inducing its downstream gene PHF in the Hpt cells. With its ability to promote the survival, proliferation and differentiation of Hpt cells, astakine 1 is proven to be an important hematopoietic growth factor.
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| 5. |
- Lin, Xionghui, et al.
(författare)
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Identification and properties of a receptor for the invertebrate cytokine astakine, involved in hematopoiesis
- 2009
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 315:7, s. 1171-1180
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Tidskriftsartikel (refereegranskat)abstract
- We have recently isolated an invertebrate cytokine from a freshwater crayfish, which we named astakine 1. Interestingly this protein is expressed exclusively in hemocytes and hematopoietic tissue and is essential for the release of new hemocytes into the open circulatory system of these animals. This astakine has a prokineticin (PK) domain but lacks the N-terminal AVIT amino acids and hence receptor binding may differ from vertebrate PKs. Accordingly, here we report that a receptor for astakine 1 on hematopoietic tissue (Hpt) cells is identical to the beta-subunit of F1ATP synthase. In this study we have used several different methods to clearly demonstrate that ATP-synthase is located on the plasma membrane of a subpopulation of Hpt cells and there may function as a receptor for astakine, whereas mature blood cells (hemocytes) do not have any ATP-synthase on the outside of their plasma membranes. Our results clearly show that ATP synthase beta subunits are present on the cell surface of Hpt cells and highlight the need for more detailed studies on intracellular traffic connections between mitochondria and other membrane compartments.
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| 6. |
- Lin, Xionghui, 1976-, et al.
(författare)
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Invertebrate astakines - regulators of differentiation in hematopoietic tissues
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Hematopoiesis is the process by which hemocytes mature and subsequently enter the circulation. Vertebrate prokineticins are known to take part in this process, as are the invertebrate prokineticin domain proteins, astakines. In Pacifastacus leniusculus astakine 1 is essential for the release of new hemocytes into the open circulatory system of these animals. In addition to astakine 1 we have now cloned a homologue of astakine 1 with an insert of 13 amino acids, named astakine 2. Common to both crustacean astakines is the lack of the N-terminal AVIT amino acids present in vertebrate PKs, and hence receptor binding differs from that of vertebrate PKs. Now we have found astakine-like sequences in 19 different invertebrate species and the sequences show that some motifs are conserved among invertebrate groups. Previously we showed that astakine 1 is directly involved in hematopoiesis and now we show that astakine 1 and astakine 2 have different roles in hemocyte lineage differentiation and that astakine 1 specifically induce differentiation along the semigranular cell lineage. Further we discuss the impact of the putative structure of different astakines in comparison with the vertebrate prokineticins.
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| 7. |
- Lin, Xionghui, et al.
(författare)
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Invertebrate Hematopoiesis : An Astakine-Dependent Novel Hematopoietic Factor
- 2011
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 186:4, s. 2073-2079
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Tidskriftsartikel (refereegranskat)abstract
- A novel factor, named crustacean hematopoietic factor (CHF), was identified from a library of suppression subtractive hybridization with the aim to find downstream genes of an invertebrate cytokine, astakine 1, in the freshwater crayfish Pacifastacus leniusculus. CHF is a small cysteine-rich protein (∼9 kDa) with high similarity to the N-terminal region of vertebrate CRIM1 in containing an insulin growth factor binding protein variant motif with unknown function. CHF was found to be induced in primary cell cultures of crayfish hematopoietic tissue (Hpt) cells (precursors of crayfish blood cells) after treatment with astakine 1. Silencing of CHF did not affect the renewal of Hpt cells in vitro, but induced apoptosis of Hpt cells. CHF is exclusively expressed in the blood cell lineage of crayfish (Hpt cells and blood cells), and in vivo RNA interference experiments show that knockdown of this gene results in severe loss of blood cells and a higher apoptotic rate in Hpt. Our data further suggest that crayfish CHF is critical for the survival of hemocytes and Hpt cells by preventing their apoptosis, thus it plays an important role in hemocyte homeostasis in crayfish. Our study of CHF may also shed light on the function of this untypical insulin growth factor binding protein motif located in the N-terminal of vertebrate CRIM1.
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| 8. |
- Lin, Xionghui, et al.
(författare)
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Purification of properoxinectin, a myeloperoxidase homologue and its activation to a cell adhesion molecule
- 2007
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165 .- 1872-8006. ; 1770:1, s. 87-93
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Tidskriftsartikel (refereegranskat)abstract
- Peroxidases are important mediators of innate immune reactions throughout the animal kingdom. In many arthropods a myeloperoxidase homologue, peroxinectin, is known to function as a cell adhesion factor and an opsonin. Here, we report in the freshwater crayfish Pacifastacus leniusculus the isolation of properoxinectin, inactive in cell adhesion, and we also show that properoxinectin is produced in the mature blood cells whereas the hematopoietic tissue contains very little of this protein. Both properoxinectin and peroxinectin are catalytically active as peroxidases, at least when using low molecular weight substrates. The extracellular processing of properoxinectin into an active cell adhesion protein was found to involve proteolytic steps shared with the prophenoloxidase activating system to yield catalytically active phenoloxidase. Thus, the regulation of activities by two ancient metalloproteins, both potentially producing highly toxic substances aimed at pathogens, is carried out by limited proteolysis. The proteolytic processing is triggered in the presence of microbial compounds such as beta-glucans or lipopolysaccharide after the release of properoxinectin and prophenoloxidase activating serine proteinases from the blood cells.
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| 9. |
- Lin, Xionghui, et al.
(författare)
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Transglutaminase activity in the hematopoietic tissue of a crustacean, Pacifastacus leniusculus, importance in hemocyte homeostasis
- 2008
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Ingår i: BMC Immunology. - : Springer Science and Business Media LLC. - 1471-2172. ; 9:58, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Transglutaminases (TGases) form a group of enzymes that have many different substrates and among the most well known are fibrin for Factor XIIIa and the clotting protein in crustaceans. We also found that TGase is an abundant protein in the hematopoietic tissue (Hpt) cells of crayfish and hence we have studied the possible function of this enzyme in hematopoiesis. RESULTS: TGase is one of the most abundant proteins in the Hpt and its mRNA expression as well as enzyme activity is very high in the Hpt cells, lesser in the semi-granular hemocytes and very low in the granular cells. In cultured hematopoietic tissues, high activity was present in cells in the centre of the tissue, whereas cells migrating out of the tissue had very low TGase activity. RNAi experiments using dsRNA for TGase completely knocked down the transcript and as a result the cell morphology was changed and the cells started to spread intensely. If astakine, a cytokine directly involved in hematopoiesis, was added the cells started to spread and adopt a morphology similar to that observed after RNAi of TGase. Astakine had no effect on TGase expression, but after a prolonged incubation for one week with this invertebrate cytokine, TGase activity inside and outside the cells was completely lost. Thus it seems as if astakine addition to the Hpt cells and RNAi of TGase in the cell culture will lead to the same results, i.e. loss of TGase activity in the cells and they start to differentiate and spread. CONCLUSION: The results of this study suggest that TGase is important for keeping the Hpt cells in an undifferentiated stage inside the hematopoietic tissue and if expression of TGase mRNA is blocked the cells start to differentiate and spread. This shows a new function for transglutaminase in preventing hematopoietic stem cells from starting to differentiate and migrate into the hemolymph, whereas their proliferation is unaffected. Astakine is also important for the hematopoiesis, since it induces hemocyte synthesis in the Hpt but now we also show that it in some unknown way participates in the differentiation of the Hpt cells.
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| 10. |
- Noonin, Chadanat, et al.
(författare)
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Invertebrate hematopoiesis : an anterior proliferation centre as a link between the hematopoietic tissue and the brain
- 2012
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 21:17, s. 3173-3186
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Tidskriftsartikel (refereegranskat)abstract
- During evolution, the innate and adaptive immune systems developed to protect organisms from nonself substances. The innate immune system is phylogenetically more ancient and is present in most multicellular organisms, whereas adaptive responses are restricted to vertebrates. Arthropods, lack the blood cells of the lymphoid lineage, and oxygen-carrying erythrocytes, making them suitable model animals to study the regulation of the blood cells of the innate immune system. Many crustaceans have a long life span and need to continuously synthesize blood cells, in contrast to many insects. The hematopoietic tissue (HPT) of Pacifastacus leniusculus provides a simple model to study hematopoiesis because the tissue can be isolated and the proliferation of stem cells and their differentiation can be studied both in vivo and in vitro. Here we demonstrate new findings of a physical link between the HPT and the brain. Actively proliferating cells were localized to an anterior proliferation centre (APC) in the anterior part of the tissue near the area linking the HPT to the brain, whereas more differentiated cells were detected in the posterior part. The central areas of HPT expand in response to lipopolysaccharide-induced blood loss. Cells isolated from the APC divide rapidly and form cell clusters in vitro; conversely, the cells from the remaining HPT form monolayers, and they can be induced to differentiate in vitro. Our findings offer an opportunity to learn more about invertebrate hematopoiesis and its connection to the central nervous system and thereby to obtain new information about the evolution of different blood and nerve cell lineages.
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