Regulation of lipoprotein lipase mRNA content in 3T3-L1 cells by tumour necrosis factor.
Tumour necrosis factor (TNF) was previously shown to suppress lipoprotein lipase (LPL) synthesis and activity in 3T3-L1 adipocytes. The present study examined the effect of TNF on amounts of mRNA for LPL in 3T3-L1 cells. Northern-blot analysis of polyadenylated RNA using a cDNA probe to guinea-pig LPL identified two predominant species of LPL message, 3.7 and 3.9 kilobases in size. The steady-state amounts of these mRNAs increased 10-fold upon expression of the adipocyte phenotype. A single dose of 1.5 nM-TNF decreased LPL mRNA by approx. 60% in 17 h with a corresponding decrease in LPL activity, an effect that was reversed 48 h after exposure to TNF. The results demonstrate that TNF reversibly down-regulates LPL mRNA in fully differentiated 3T3-L1 adipocytes. Cells induced to differentiate in the presence of 1.5 nM-TNF exhibited a delayed time course for development of the adipocyte phenotype, as judged by attenuation of the normal increase in LPL mRNA that occurs with differentiation.
Cornelius
P
P
Department of Biochemistry, East Carolina University School of Medicine, Greenville, NC 27858.
Enerback
S
S
Bjursell
G
G
Olivecrona
T
T
Pekala
P H
PH
D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D002460:Cell Line; D004587:Electrophoresis, Agar Gel; D008071:Lipoprotein Lipase / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000187:drug effects* / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D008071:Lipoprotein Lipase