Molecular mechanisms for the release of chemokines from human leukemic mast cell line (HMC)-1 cells activated by SCF and TNF-alpha: roles of ERK, p38 MAPK, and NF-kappaB.
BACKGROUND
Mast cells play pivotal roles in IgE-mediated airway inflammation and other mast cell-mediated inflammation by activation and chemoattraction of inflammatory cells.


OBJECTIVE
We investigated the intracellular signaling mechanisms regulating chemokine release from human mast cell line-1 (HMC-1) cells activated by stem cell factor (SCF) or tumor necrosis factor (TNF)-alpha.


METHODS
Chemokine gene expressions were assessed by reverse transcription-polymerase chain reaction, while the releases of chemokines were determined by flow cytometry or enzyme-linked immunosorbent assay (ELISA). To elucidate the intracellular signal transduction regulating the chemokine expression, phosphorylated-extracellular signal-regulated kinase (ERK), phosphorylated-p38 mitogen-activated protein kinase (MAPK) and nuclear translocated nuclear factor (NF)-kappaB-DNA binding were quantitatively assessed by ELISA.


RESULTS
Either SCF or TNF-alpha could induce release from HMC-1 cells of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, regulated upon activation normal T-cell expressed and secreted (RANTES), and I-309, while SCF and TNF-alpha induced release of macrophage inflammatory protein (MIP)-1beta and interferon-gamma-inducible protein-10 (IP-10), respectively. Using various selective inhibitors for signaling molecules, we found that the inductions of IL-8, MCP-1, and I-309 were mediated by either SCF-activated ERK or TNF-alpha-activated p38 MAPK, while the induction of IP-10 by TNF-alpha was mediated by both activated p38 MAPK and NF-kappaB. The induction of RANTES by SCF or TNF-alpha was mediated by ERK and NF-kappaB, respectively, and SCF induced MIP-1beta release was mediated by ERK.


CONCLUSIONS
The above results therefore elucidated the different intracellular signaling pathways regulating the release of different chemokines from SCF and TNF-alpha-activated mast cells, thereby shedding light for the immunopathological mechanisms of mast cell-mediated diseases.
Wong
C K
CK
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
Tsang
C M
CM
Ip
W K
WK
Lam
C W K
CW
D001483:Base Sequence; D015415:Biomarkers / Q000032:analysis; D045744:Cell Line, Tumor; D018925:Chemokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D019089:Stem Cell Factor / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D015415:Biomarkers; D018925:Chemokines; D016328:NF-kappa B; D012333:RNA, Messenger; D019089:Stem Cell Factor; D014409:Tumor Necrosis Factor-alpha; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases