Co-regulated expression of glomerular 12/15-lipoxygenase and interleukin-4 mRNAs in rat nephrotoxic nephritis.
Arachidonate 12- and 15-lipoxygenase (LO) products are generated in experimental glomerulonephritis. 15-S-HETE (a 15-LO product) and lipoxins (interaction products between 5-LO and either 12-LO or 15-LO) counteract the proinflammatory actions of leukotrienes. IL-4 has been shown to up-regulate 15-LO gene expression in human leukocytes. Based on homology with human 15-LO, we cloned a 0.76 kbp fragment of a rat LO cDNA from leukocytes stimulated by interleukin-4 (IL-4). The deduced amino acid sequence shows 71.0% and 60.1% homology to human 15-LO and 12-LO, respectively, and 100% homology to a recently cloned "leukocyte type" rat 12-lipoxygenase enzyme, which possesses significant 15-lipoxygenase activity (heretofore referred to as "12/15-LO"). A deletion mutant was utilized to generate internal standard cRNA in quantitative PCR assays. Glomerular 12/15-LO mRNA increased significantly over controls 24 and 48 hours after NTS injection, then decreased at 72 hours. RNA from NTS glomeruli contained higher levels of 12/15-LO mRNA than that from unstimulated peripheral leukocytes, suggesting that 12/15-LO transcription is up-regulated locally in native and/or infiltrating glomerular cells. Glomerular IL-4 mRNA increased markedly 16 hours post-NTS, and was then reduced, suggesting a potential role for T cell-derived IL-4 in directing the expression of 12/15-LO during glomerulonephritis. This represents the first demonstration of tandem regulated in vivo gene expression for a lymphokine (IL-4) and a lipoxygenase, both of which promote counter-inflammatory influences in immune complex-mediated injury.
Department of Medicine, Emory University, Atlanta, Georgia.
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T
Katoh
F G
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Lakkis
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Makita
K F
KF
Badr
D000595:Amino Acid Sequence; D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000378:metabolism; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics / Q000378:metabolism; D001091:Arachidonate Lipoxygenases / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005786:Gene Expression Regulation; D005921:Glomerulonephritis / Q000201:enzymology*; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism*; D007678:Kidney Glomerulus / Q000201:enzymology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D012333:RNA, Messenger; D015847:Interleukin-4; D001091:Arachidonate Lipoxygenases; D001092:Arachidonate 12-Lipoxygenase; D001093:Arachidonate 15-Lipoxygenase