The Journal of Neuroscience, July 1, 2002, 22(13):5334-5343
Prostaglandin E2 Is a Novel Inducer of Oncostatin-M
Expression in Macrophages and Microglia
Pavle
Repovic and
Etty N.
Benveniste
Department of Cell Biology, University of Alabama at Birmingham,
Birmingham, Alabama 35294
Oncostatin-M (OSM), a pluripotent cytokine of the interleukin-6
(IL-6) family, is produced in a number of inflammatory conditions. Known sources of OSM include monocytes-macrophages and T-cells. Here
we present microglia, the resident macrophages of the brain, as a
source of OSM in the CNS. In this context, we describe a novel inducer
of OSM, prostaglandin E2 (PGE2).
PGE2 induces OSM expression in microglia, monocytes, and
macrophages of human and murine origin. PGE2 induction of
OSM is mimicked by cholera toxin, an activator of stimulatory G
(Gs)-proteins; by forskolin, an activator of
adenylate cyclase; and by the cAMP analog, dibutyryl-cAMP. PGE2 induction of OSM gene expression is inhibited by the
adenylate cyclase inhibitor 2',5'-dideoxyadenosine, by the protein
kinase A (PKA) inhibitor H-89, and by a dominant-negative PKA
construct. These data indicate that PGE2 signals via
Gs-protein-coupled receptor(s), adenylate cyclase, and PKA
to induce OSM expression. Accordingly, other activators of cAMP
signaling such as norepinephrine and PGE1 induce OSM. The
ability of PGE2 to induce OSM expression was tested under
more physiological conditions, using cocultures of astrocytes and
monocytes. Treatment of the cocultures with IL-1
or tumor necrosis
factor-
(TNF-
) results in production of PGE2 and OSM.
PGE2 produced in the cocultures is responsible for OSM
induction, because pretreatment with indomethacin, an inhibitor of
prostaglandin synthesis, as well as depletion of PGE2, abrogate OSM expression induced by IL-1
or
TNF-
. These data suggest that in the CNS, OSM may be produced
through collaboration of astrocytes and macrophages-microglia.
Key words:
oncostatin-M; prostaglandin E2; microglia; macrophage; astrocytes; cAMP
Copyright © 2002 Society for Neuroscience 0270-6474/02/22135334-10$05.00/0