A novel hematopoietic granulin induces proliferation of goldfish (Carassius auratus L.) macrophages.
Granulins are a group of highly conserved growth factors that have been described from a variety of organisms spanning the metazoa. In this study, goldfish granulin was one of the most commonly identified transcripts in the differential cross-screening of macrophage cDNA libraries and was preferentially expressed in proliferating macrophages. Unlike mammalian granulins, which possess 7.5 repeats of a characteristic signature of 12 cysteine residues, the goldfish granulin encoded a putative peptide possessing only 1.5 cysteine repeats. Northern blot and real-time PCR analyses indicated that goldfish granulin was expressed only in the hematopoietic tissues of the goldfish, specifically the kidney and spleen, and in activated peripheral blood mononuclear cells. We expressed granulin using a prokaryotic expression system and produced an affinity-purified rabbit anti-goldfish granulin IgG. Recombinant goldfish granulin induced a dose-dependent proliferative response of goldfish macrophages that was inversely related to the myeloid differentiation stage of the cells studied. The highest proliferative response was observed in macrophage progenitor cells and monocytes. This proliferative response of macrophages was abrogated by the addition of anti-granulin IgG. These results indicate that goldfish granulin is a growth factor that positively modulates cell proliferation at distinct junctures of macrophage differentiation.
Department of Biological Sciences, CW-405 Biological Sciences Building, University of Alberta, Edmonton, Alberta T6G E9, Canada.
Patrick C
PC
Hanington
Daniel R
DR
Barreda
Miodrag
M
Belosevic
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D015723:Gene Library; D006054:Goldfish; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D007249:Inflammation; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry*; D007668:Kidney / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010802:Phylogeny; D000077153:Progranulins; D012313:RNA / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
D018076:DNA, Complementary; D007074:Immunoglobulin G; D036341:Intercellular Signaling Peptides and Proteins; D000077153:Progranulins; D011994:Recombinant Proteins; D012313:RNA; D004247:DNA; D003545:Cysteine