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Gene expression during differentiation of human dendritic cells from cord blood cd34 stem cells
G M Fisher1, S Iqball, S C Knight
1Antigen Presentation Research Group, Imperial College of Science Technology & Medicine, Northwick Part Institute for Medical Research, Harrow, HA1 3UJ, Middlesex, UK. g.fisher@ic.ac.uk
Insights
Human cord blood stem cells differentiate into dendritic cells (DC) expressing cytokine receptors. These CD1a+ dendritic cells (DC) show potential to respond to various signals, with constitutive expression of IL-12 receptor mRNA.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Human cord blood CD34(+) stem cells are a source for generating dendritic cells (DC).
- Cytokines like stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha) are used in DC differentiation.
- Dendritic cells (DC) play a crucial role in initiating immune responses.
Purpose of the Study:
- To investigate the differentiation of human cord blood CD34(+) stem cells into CD1a+ dendritic cells (DC).
- To analyze the expression of cytokine receptors and STATs mRNA in the generated CD1a+ DC populations.
- To understand the potential of these DC to respond to maturational signals.
Main Methods:
- CD34(+) stem cells from human cord blood were cultured with SCF, GM-CSF, and TNF-alpha.
- Flow cytometry was used to identify and quantify CD1a+ cells.
- Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect mRNA expression of various cytokine receptors (IL-2R, IL-3R, IL-6R, IL-12R, IL-4R) and STATs (STAT3, STAT4).
Main Results:
- Functional CD1a+ dendritic cells (DC) were generated from CD34(+) stem cells.
- CD1a+ DC populations exhibited constitutive expression of IL-2R, IL-3R, IL-6R, IL-12R, STAT3, and STAT4 mRNA.
- Unexpectedly, IL-12 receptor mRNA was found in CD1a+ DC, which are typically considered myeloid.
- Intermittent expression of IL-12p35 and IL-4R mRNA was observed, suggesting inducible gene expression.
Conclusions:
- Generated CD1a+ DC express a range of cytokine receptors, indicating responsiveness to diverse maturational signals.
- The constitutive expression of IL-12 receptor mRNA in CD1a+ DC warrants further investigation into their immune function.
- These findings contribute to understanding the plasticity and potential signaling pathways of dendritic cells derived from cord blood stem cells.
Abstract:
Human cord blood CD34(+)stem cells were allowed to differentiate in the presence of cytokines stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor alpha (TNF-alpha) into functional CD1a+dendritic cells (DC). A maximum of 1.9 x 10(6) CD1a+ cells were separated from the cells generated from 1.2 x 10(6) CD34(+) stem cells from an individual donor. The percentage of CD1a+cells separated rose to a maximum of 27% at day 11 and fell to 8% at 21 days. Reverse transcription-polymerase chain reaction analysis showed that interleukin 2 receptor, interleukin 3 receptor, interleukin 6 receptor, interleukin 12 receptor (IL-12R) and signal transducer and activator of transcription (STAT) 3, STAT 4 mRNA was expressed in all CD1a+cell populations throughout and appears to be constitutive. Expression of IL-12RmRNA was unexpected in CD1a+DC normally considered to be of myeloid lineage. Expression of interleukin 12 (IL-12) p40 subunit mRNA was not detected. Intermittent expression of the IL-12p35 subunit and IL-4R mRNA suggested that gene expression is inducible, but not obviously correlated with progressive DC development. Expression of mRNA for a spectrum of cytokine receptors indicates that CD1a+DC have the potential to respond to a variety of maturational signals.