Swiprosin-1 Regulates Cytokine Expression of Human Mast Cell Line HMC-1 through Actin Remodeling.
BACKGROUND
Swiprosin-1 was identified in human CD8+ lymphocytes, mature B cells and non-lymphonoid tissue. We have recently reported that swiprosin-1 is expressed in mast cells and up-regulated in both in vitro and in vivo.


METHODS
The expression of cytokines and swiprosin-1 were determined by by real time PCR and conventional PCR. Pharmacological inhibitors were treated to investigate potential mechanism of swiprosin-1 in mast cell activation. Actin content was evaluated by confocal microscopy and flow cytometry.


RESULTS
The swiprosin-1 augmented PMA/A23187-induced expression of cytokines and release of histamine. However, knock-down of swiprosin-1 showed only a modest effect on PMA/A23187-induced cytokine expression, suggesting that swiprosin-1 has gain-of-function characteristics. Swiprosin-1 was found in microvilli-like membrane protrusions and highly co-localized with F-actin. Importantly, either disruption of actin by cytochalasin B or inhibition of PI3 kinase, an enzyme involved in actin remodeling, by wortmannin blocked cytokine expression only in swiprosin-1-overexpressing cells.


CONCLUSIONS
These results suggest that swiprosin-1 modulates mast cell activation potentially through actin regulation.
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
T P
TP
Ramesh
Young-Dae
YD
Kim
Min-Sung
MS
Kwon
Chang-Duk
CD
Jun
Sang-Wook
SW
Kim