title: Hemocyte production and maturation in an invertebrate animal; proliferation and gene expression in hematopoietic stem cells of Pacifastacus leniusculus.
abstract: Regulation of hematopoiesis in invertebrates is largely unknown, although the hemocytes are essential in immunity, performing functions such as phagocytosis, encapsulation and lysis of foreign cells. We have developed a method to isolate hematopoietic stem cells from the freshwater crayfish, Pacifastacus leniusculus, and therefore, this animal provides a powerful tool for studies on invertebrate hematopoiesis. The hematopoietic tissue of crayfish was found to be actively proliferating. Injection of a beta1,3-glucan caused a severe loss of hemocytes, followed by a rapid recovery, due to release from the hematopoietic organ. Transcripts for peroxinectin, a hemocyte cell adhesion protein, were present in the hematopoietic cells, whereas mRNA for proPO was not detected. A gene coding for a Runt-domain protein known to be involved in hematopoiesis in Drosophila and mammals, was upregulated prior to hemocyte release.We conclude that hemocytes are synthesised and partly differentiated in the hematopoietic tissue, but the final differentiation into functional hemocytes expressing proPO is not completed until the hemocytes are released into the circulation.
authors.affiliation: Department of Comparative Physiology, Evolutionary Biology Centre, Uppsala University, 18A, Uppsala 752 36 Norbyvägen, Sweden. irene.soderhall@ebc.uu.se
authors.forename: Irene
authors.initials: I
authors.lastname: Söderhäll
authors.forename: Eakaphun
authors.initials: E
authors.lastname: Bangyeekhun
authors.forename: Susan
authors.initials: S
authors.lastname: Mayo
authors.forename: Kenneth
authors.initials: K
authors.lastname: Söderhäll
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D003400:Astacoidea / Q000502:physiology*; D001798:Blood Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015152:Blotting, Northern; D004156:Catechol Oxidase / Q000235:genetics / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D019070:Cell Lineage; D004792:Enzyme Precursors / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D015870:Gene Expression; D005936:Glucans; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000502:physiology; D006434:Hemocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011134:Polysaccharides / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D000925:Anticoagulants; D001798:Blood Proteins; D015815:Cell Adhesion Molecules; D004792:Enzyme Precursors; D005936:Glucans; D009363:Neoplasm Proteins; D011134:Polysaccharides; D014157:Transcription Factors; C096867:peroxinectin protein, Pacifastacus leniusculus; C008247:laminaran; C038451:pro-phenoloxidase; D004156:Catechol Oxidase