Ca. Louis et al., DISTINCT ARGINASE ISOFORMS EXPRESSED IN PRIMARY AND TRANSFORMED MACROPHAGES - REGULATION BY OXYGEN-TENSION, American journal of physiology. Regulatory, integrative and comparative physiology, 43(3), 1998, pp. 775-782
Experiments were performed to identify arginase isoforms expressed in
primary and transformed rodent macrophages and to determine the molecu
lar mechanisms for the previously observed increase in arginase activi
ty in macrophages cultured in hypoxia or anoxia. Results demonstrate t
he following: 1) mRNA and protein for hepatic-type Al arginase are exp
ressed in primary cultures of rat and mouse peritoneal macrophages and
are enhanced seven-and ninefold, respectively, by lipopolysaccharide
(LPS). 2) mRNA for extrahepatic-type AII arginase is constitutively ex
pressed in mouse, but not rat, peritoneal macrophages and is detected
in RAW264.7 cells after LPS treatment; neither J774A.1 nor P388D(1) ce
lls contain arginase mRNA. 3) AI arginase mRNA, arginase activity in c
ell lysates, and L-arginine flux through arginase in intact cells are
all increased in rat wound-derived and mouse peritoneal macrophages by
hypoxide or anoxic culture; AII arginase mRNA is, in contrast, suppre
ssed >50% by O-2 deprivation. 4) Expression of the L-arginine transpor
ter mCAT-2 is increased greater than twofold by reduced O-2 culture. T
hese results demonstrate substantial variability in arginase isoform e
xpression among primary and transformed rodent macrophages, They also
identify AI and AII arginase and the mCAT-2 L-arginine transporter as
O-2-regulated genes.