Evidence for distinct intracellular signaling pathways in CD34+ progenitor to dendritic cell differentiation from a human cell line model.
Intracellular signals that mediate differentiation of pluripotent hemopoietic progenitors to dendritic cells (DC) are largely undefined. We have previously shown that protein kinase C (PKC) activation (with phorbol ester (PMA) alone) specifically induces differentiation of primary human CD34+ hemopoietic progenitor cells (HPC) to mature DC. We now find that cytokine-driven (granulocyte-macrophage CSF and TNF-alpha) CD34+ HPC-->DC differentiation is preferentially blocked by inhibitors of PKC activation. To further identify intracellular signals and downstream events important in CD34+ HPC-->DC differentiation we have characterized a human leukemic cell line model of this process. The CD34+ myelomonocytic cell line KG1 differentiates into dendritic-like cells in response to granulocyte-macrophage CSF plus TNF-alpha, or PMA (with or without the calcium ionophore ionomycin, or TNF-alpha), with different stimuli mediating different aspects of the process. Phenotypic DC characteristics of KG1 dendritic-like cells include morphology (loosely adherent cells with long neurite processes), MHC I+/MHC IIbright/CD83+/CD86+/CD14- surface Ag expression, and RelB and DC-CK1 gene expression. Functional DC characteristics include fluid phase macromolecule uptake (FITC-dextran) and activation of resting T cells. Comparison of KG1 to the PMA-unresponsive subline KG1a reveals differences in expression of TNF receptors 1 and 2; PKC isoforms alpha, beta I, beta II, and mu; and RelB, suggesting that these components/pathways are important for DC differentiation. Together, these findings demonstrate that cytokine or phorbol ester stimulation of KG1 is a model of human CD34+ HPC to DC differentiation and suggest that specific intracellular signaling pathways mediate specific events in DC lineage commitment.
St Louis
D C
DC
Immune Cell Biology Program, Naval Medical Research Institute, Bethesda, MD 20889, USA.
Woodcock
J B
JB
Franzoso
G
G
Blair
P J
PJ
Carlson
L M
LM
Murillo
M
M
Wells
M R
MR
Williams
A J
AJ
Smoot
D S
DS
Kaushal
S
S
Grimes
J L
JL
Harlan
D M
DM
Chute
J P
JP
June
C H
CH
Siebenlist
U
U
Lee
K P
KP
Fransozo
G
G
D000328:Adult; D018952:Antigens, CD34 / Q000276:immunology*; D000954:Antigens, Surface / Q000096:biosynthesis; D017209:Apoptosis / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000502:physiology; D003713:Dendritic Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D004789:Enzyme Activation / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D007424:Intracellular Fluid / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D046911:Macromolecular Substances; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D051841:Transcription Factor RelB; D014157:Transcription Factors / Q000096:biosynthesis
D018952:Antigens, CD34; D000954:Antigens, Surface; D016207:Cytokines; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D014157:Transcription Factors; D051841:Transcription Factor RelB; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate