Distribution and expression analysis of transcription factors in tissues and progenitor cell populations of the goldfish (Carassius auratus L.) in response to growth factors and pathogens

We report on the mRNA levels of a panel of transcription factors in the kidney and spleen tissues, and in the cell populations from the blood, the spleen, and in the sorted kidney progenitor cells. The mRNA levels of cebpα, cjun, cmyb, egr1, gata1, gata2, gata3, lmo2, mafb, pax5, pu.1 and runx1 were assessed in healthy goldfish as well as in fish challenged with two different pathogens, Aeromonas salmonicida A449 or Trypanosoma carassii. Spleen tissue from healthy goldfish showed higher expression of myeloid (cjun), erythroid (gata1) and lymphoid (gata3, pax5) transcription factors, and lower expression of the myeloid transcription factor cebpα when compared to that of kidney. Splenocytes and PBLs had significantly higher mRNA levels of the transcription factors involved in myeloid (pu.1, mafb, cjun, egr1, cebpa), erythroid (gata1, lmo2), and lymphoid pathways (gata3 and pax5) compared to sorted kidney R1 progenitor cells, while R1 progenitor cells had higher mRNA levels of early progenitor transcription factors (runx1 and cmyb). Furthermore, the R1 progenitor cells had higher mRNA levels of the transcription factors involved in early progenitor cells (egr1, gata2) and the lymphoid lineage progenitors (gata3, pax5) compared to those in kidney. The mRNA levels of the transcription factors (gata2, mafb, cjun, gata1, lmo2, gata3, and pax5) in R1 progenitor cells changed during cultivation; they were elevated in day 2 R1 cells and down-regulated by day 6 of cultivation, when compared to those of day 0 R1 cells. Treatment of day 2 R1 progenitor cells with rgCSF-1 resulted in an up-regulation of transcription factors important for myeloid cell development (cjun and egr1). Similarly, rgkitla up-regulated the expressions of myeloid (mafb, egr1 and cebpa) transcription factors. Changes in the expression of transcription factors in the R1 progenitor cells were related to the observed developmental processes of myeloid progenitor cells during cultivation or treatment with recombinant growth factors in vitro. We also observed differential expressions of the transcription factors in R1 progenitor cells following exposure of the goldfish to either prokaryotic (heat-killed A. salmonicida A449) or eukaryotic (T. carassii) pathogens.