Studies of the Mechanisms of Myelopoiesis in Goldfish (Carassius auratus L.)

• Author / Creator

  Katzenback, Barbara A

• Development of progenitor cells into myeloid cells (i.e. macrophages and neutrophils) is critical to the survival of metazoans for maintenance of homeostasis and defense against pathogens. While much is known about myeloid cell development in mammals, less is known about this process in fish. The objective of my thesis was to characterize the myeloid progenitor cell subpopulations of goldfish, their growth factors, receptors and transcription factors (TFs) involved in the process of myeloid cell development (myelopoiesis). Goldfish kita receptor and its ligand, kitla, were cloned, expressed and characterized. The kita was highly expressed in progenitor cells, compared to monocytes and mature macrophages. The recombinant KITLA was glycosylated, formed non-covalent homodimers, induced a progenitor cell chemotactic response and promoted the survival of progenitor cells. These results suggest a role for KITA/KITLA in the retention and survival of progenitor cells. Colony stimulating factor-1 receptor (CSF-1R) is important for macrophage development. Antibody to goldfish CSF-1R was shown to specifically identify cells of the macrophage lineage, including a subpopulation of progenitor cells. The CSF-1R+ population of progenitor cells decreased with time of culture, coinciding with the generation of monocytes and macrophages. The assessment of mRNA levels of a panel of TFs in progenitor cells showed that this cell population was committed to the macrophage lineage by day 2 of cultivation. Addition of rgKITLA and rgCSF-1 to progenitor cells modulated specific myeloid TF mRNA levels consistent with the functional characterization studies. A procedure for the isolation of highly purified primary neutrophils was developed in this study. Primary neutrophils, isolated from the goldfish kidney produced, reactive oxygen intermediates and degranulated after exposure to mitogens and the fish pathogen, Aeromonas salmonicida, in a dose- and time-dependent manner. Goldfish granulocyte colony stimulating factor receptor (gcsfr) was identified and expressed by neutrophils. gcsfr mRNA levels were found to be significantly higher after exposure of neutrophils to mitogens or A. salmonicida, suggesting a role for GCSFR in neutrophil survival or activation during inflammation. Taken together, my results highlight the importance of growth factors, receptors and transcription factors in the modulation of goldfish myelopoiesis.

• Subjects / Keywords

  • Colony-stimulating factor-1 receptor
  • Myelopoiesis
  • Stem cell factor
  • Monopoiesis
  • Macrophages
  • Kit receptor
  • Progenitor cells
  • Transcription factors
  • Granulopoiesis
  • Colony-stimulating factor-1
  • Granulocyte colony-stimulating factor receptor
  • Goldfish

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3B71R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.