Connective tissue mast cells in contact with fibroblasts express IL-3 mRNA. Analysis of single cells by polymerase chain reaction.
Mast cell-fibroblast interactions have been extensively investigated in the last few years. Fibroblasts support the in vitro survival but not proliferation of mouse connective-tissue type mast cells. However, the factor(s) that allow their survival on fibroblast monolayers has not been identified. We have investigated the presence of mRNA for IL-3 and granulocyte-macrophage-CSF in single mouse mast cells, before and after co-culture with 3T3 fibroblasts, using the polymerase chain reaction technique. The system was calibrated first by using in vitro generated population of mouse bone-marrow derived mast cells (BMMC). Significant differences in the amplification of IL-3 cDNA were observed in each of the BMMC cells examined, whereas the amplification of cDNA for the alpha-subunit of the Fc epsilon RI were similar. Inasmuch as murine cultured IL-3-dependent mast cells differentiate into connective tissue-like mast cells when co-cultured with 3T3 fibroblasts without any exogenous supply of growth factors, it was of interest to determine whether these connective tissue-like mast cells produce IL-3 message. Separation of the differentiated BMMC from the fibroblast monolayer, by either trypsinization or by single cell manipulation revealed the synthesis of a detectable amount of IL-3 mRNA in these mast cells. Whether this IL-3 mRNA was induced by fibroblasts was further investigated using connective tissue mast cells freshly purified from the mouse peritoneal cavity. Only about 20% of these connective tissue mast cells produced detectable amount of granulocyte-macrophage-CSF mRNA whereas in less than 10% of the cells IL-3 mRNA was detected. However, when these connective tissue mast cells were co-cultured with 3T3 fibroblasts for 18 hours and then separated, IL-3 mRNA were detected in most of the cells whereas no such mRNA was detected in tissue mast cells incubated for 18 h with medium derived from 3T3 fibroblasts. Therefore we conclude that fibroblasts induce the accumulation of IL-3 mRNA in connective tissue mast cells. The production of IL-3 may play a role in the survival of this type of mast cells on the fibroblast monolayer.
Razin
E
E
Institute of Biochemistry, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Leslie
K B
KB
Schrader
J W
JW
D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics; D002450:Cell Communication; D002478:Cells, Cultured; D003239:Connective Tissue Cells; D005260:Female; D005347:Fibroblasts / Q000502:physiology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics*; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis*; D011961:Receptors, Fc / Q000235:genetics; D017452:Receptors, IgG
D000943:Antigens, Differentiation; D007377:Interleukin-3; D012333:RNA, Messenger; D011961:Receptors, Fc; D017452:Receptors, IgG; D016178:Granulocyte-Macrophage Colony-Stimulating Factor