T. Wu et al., ANTISENSE INHIBITION OF 85-KDA CPLA(2) BLOCKS ARACHIDONIC-ACID RELEASE FROM AIRWAY EPITHELIAL-CELLS, American journal of physiology. Lung cellular and molecular physiology, 17(2), 1997, pp. 331-338
Inflammatory cytokines play a critical role in the initiation and perp
etuation of inflammation. Several cytokines are known to increase the
production of arachidonic acid (AA) metabolites, which may mediate cyt
okine-induced acute and chronic inflammation. Although cytokines upreg
ulate phospholipase A(2) (PLA(2)) in several target cells, the contrib
ution of individual PLA(2) to cytokine-induced AA release and eicosano
id production remains unclear because of the existence of various form
s of cellular PLA(2). To examine the role of 85-kDa cytosolic PLA(2) (
cPLA(2)) in cytokine-induced AA release, a system was developed to inh
ibit the expression of cPLA(2) in a human bronchial epithelial cell li
ne (BEAS-2B cells) by antisense RNA. Cells stably expressing antisense
cPLA(2) exhibited decreased cPLA(2) protein levels as well as decreas
ed cPLA(2) activity assayed in vitro. The effects of cytokines interfe
ron-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and in
terleukin-1 alpha (IL-1 alpha) on the release of prelabeled [H-3]AA we
re then tested in cells stably transfected with vector alone as well a
s cells transfected with cPLA(2) antisense plasmid. IFN-gamma (300 U/m
l), TNF-alpha (20 ng/ml), and IL-1 alpha (20 ng/ml) all induced a sign
ificantly increased release of prelabeled [H-3]AA after 15 min to 2 h
of treatment in control cells, and their effects were significantly re
duced in cells transfected with cPLA(2) antisense vector. These result
s demonstrate a critical role of cPLA(2) in inflammatory cytokine-indu
ced AA metabolism.