BACKGROUND: Mast cells (MCs) arise from haematopoietic stem cells. We have recently reported that CD34(+) progenitors derived from human bone marrow (BM) develop into tryptase+, chymase+ MCs when cultured in the presence of recombinant human stem cell factor (rhSCF) and recombinant human IL-6 (rhIL-6). In an experiment for the expression of chymase during differentiation, chymase+ cells were detected in human BM, but tryptase+ cells were not found. OBJECTIVE: The purpose of this study was to show the appearance of chymase+ cells in CD34(+) cells with an origin different from MC differentiation. METHODS: CD34(+) cells from human BM were sorted with anti-CD117 monoclonal antibody (mAb), and cytospins of CD34(+), CD34(+)CD117(+), or CD34(+)CD117(-) were prepared. These cells were cultured with rhSCF+rhIL-6 for 12 weeks. Some of the cells were subjected to either histological stain with Wright-Giemsa or immunocytochemistry with anti-chymase mAb. Real-time RT-PCR was also performed to compare the transcriptional level of chymase from each cell preparation. RESULTS: Chymase was expressed in CD34(+) cells as well as human MCs by immunocytochemistry. Substantial CD34(+)CD117(-) cells, but not CD34(+)CD117(+) cells, were stained immunocytochemically with anti-chymase mAb. For 1 week culture with rhSCF+rhIL-6, no cells expressed chymase in any preparation. Real-time RT-PCR revealed positivity for chymase mRNA in CD34(+) cells, but it reduced at 1 week of culture, and increased as cells developed into MCs. Chymase mRNA in CD34(+)CD117(+) cells was negligible compared with that in CD34(+)CD117(-). Tryptase mRNA was below the detectable level in CD34(+) cells, and increased along with MC differentiation. After 12 weeks of culture, CD34(+)CD117(+) developed predominantly into MCs, whereas CD34(+)CD117(-) developed into monocytes/macrophages. CONCLUSION: Our findings suggested that chymase is present not only in MCs but also in CD34(+)CD117(-) BM progenitors, but that its origin is different from the MC lineage.
BACKGROUND: Mast cells (MCs) arise from haematopoietic stem cells. We have recently reported that CD34(+) progenitors derived from human bone marrow (BM) develop into tryptase+, chymase+ MCs when cultured in the presence of recombinant humanstem cell factor (rhSCF) and recombinant humanIL-6 (rhIL-6). In an experiment for the expression of chymase during differentiation, chymase+ cells were detected in human BM, but tryptase+ cells were not found. OBJECTIVE: The purpose of this study was to show the appearance of chymase+ cells in CD34(+) cells with an origin different from MC differentiation. METHODS:CD34(+) cells from human BM were sorted with anti-CD117 monoclonal antibody (mAb), and cytospins of CD34(+), CD34(+)CD117(+), or CD34(+)CD117(-) were prepared. These cells were cultured with rhSCF+rhIL-6 for 12 weeks. Some of the cells were subjected to either histological stain with Wright-Giemsa or immunocytochemistry with anti-chymase mAb. Real-time RT-PCR was also performed to compare the transcriptional level of chymase from each cell preparation. RESULTS:Chymase was expressed in CD34(+) cells as well as human MCs by immunocytochemistry. Substantial CD34(+)CD117(-) cells, but not CD34(+)CD117(+) cells, were stained immunocytochemically with anti-chymase mAb. For 1 week culture with rhSCF+rhIL-6, no cells expressed chymase in any preparation. Real-time RT-PCR revealed positivity for chymase mRNA in CD34(+) cells, but it reduced at 1 week of culture, and increased as cells developed into MCs. Chymase mRNA in CD34(+)CD117(+) cells was negligible compared with that in CD34(+)CD117(-). Tryptase mRNA was below the detectable level in CD34(+) cells, and increased along with MC differentiation. After 12 weeks of culture, CD34(+)CD117(+) developed predominantly into MCs, whereas CD34(+)CD117(-) developed into monocytes/macrophages. CONCLUSION: Our findings suggested that chymase is present not only in MCs but also in CD34(+)CD117(-) BM progenitors, but that its origin is different from the MC lineage.
Authors: Águida Cristina Gomes Henriques; Roseana de Almeida Freitas; Bruno Cunha Pires; Clarissa Araújo Gurgel; Jean Nunes Dos Santos Journal: An Bras Dermatol Date: 2016 Sep-Oct Impact factor: 1.896