Fetal hepatic expression of 5-lipoxygenase activating protein is confined to colonizing hematopoietic cells.
Leukotriene C(4) is a potent inflammatory mediator formed from arachidonic acid and glutathione. 5-Lipoxygenase (5-LO), 5-lipoxygenase activating protein (FLAP) and leukotriene C(4) synthase (LTC(4)S) participate in its biosynthesis. We report evidence from insitu hybridization experiments that FLAP mRNA is abundantly expressed in fetal mouse liver from e11.5 until delivery. In contrast very little or no FLAP mRNA was detected in adult liver. The fetal expression in liver was not uniform but occurred in patches. Cells from e15.5 livers were fractionated by fluorescence activated cell sorting into hepatocytes and other CD45(-) cells and CD45(+) hematopoietic cells. The latter were further separated into immature (Lin(-)) and mature (Lin(+)) cells and analyzed for FLAP mRNA content by quantitative RT-PCR. FLAP mRNA expression was confined to CD45(+) cells and the mature cells had approximately 4-fold higher FLAP mRNA levels compared to the immature cells.
Strid
Tobias
T
Department of Clinical and Experimental Medicine, Linköping University, Sweden.
Karlsson
Cecilia
C
Söderström
Mats
M
Zhang
Jie
J
Qian
Hong
H
Sigvardsson
Mikael
M
Hammarström
Sven
S
D058927:5-Lipoxygenase-Activating Proteins; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D047108:Embryonic Development; D005333:Fetus / Q000201:enzymology*; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D017404:In Situ Hybridization, Fluorescence; D008099:Liver / Q000196:embryology* / Q000201:enzymology*; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D058927:5-Lipoxygenase-Activating Proteins; C548593:Alox5ap protein, mouse; D002352:Carrier Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D001094:Arachidonate 5-Lipoxygenase