Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using differential hybridization techniques we have isolated a hamster cDNA encoding a cholesterol-regulated protein. By sequence homology we concluded that the isolated cDNA encodes alpha 1-inhibitor III (alpha 1 I3), a protein of the alpha-macroglobulin (alpha M) family. When hamsters were fed diets rich in cholesterol, cholic acid, or chenodeoxycholic acid, the amount of alpha 1I3 RNA was reduced between 5- and 10-fold. Drugs that lower plasma cholesterol levels, such as colestipol and mevinolin, increased alpha 1I3 RNA between 2- and 3-fold. Additionally, plasma alpha 1I3 protein levels, as measured by immunoblotting techniques using an anti-human alpha 2M antibody, correlate well with alpha 1I3 RNA levels in those hamsters. Plasma alpha 1I3 protein was inversely proportional to plasma cholesterol levels in those hamsters. The observed suppression of alpha 1I3 expression by cholesterol mimics the cholesterol-mediated regulation of other genes that maintain cholesterol homeostasis, such as 3-hydroxy-3-methylglutaryl coenzyme A synthase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and low density lipoprotein receptor. We hypothesize that alpha 1I3 may play a role in the onset of atherosclerosis and may provide a link between cholesterol and the clotting system. Furthermore, the availability of another sterol-regulated gene, like alpha 1I3, should help elucidate the molecular mechanisms of cholesterol-mediated regulation of gene transcription.
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PMID:Cholesterol-mediated suppression of alpha 1-inhibitor III, a plasma alpha-macroglobulin family protein. 171 65

Lifibrol (4-(4'-tert. butylphenyl)-1-(4'-carboxyphenoxy)-2-butanol) is a new hypocholesterolemic compound; it effectively lowers low density lipoprotein (LDL) cholesterol. We studied the effects of lifibrol on the cholesterol metabolism of cultured cells. In the hepatoma cell line HepG2, Lifibrol decreased the formation of sterols from [14C]-acetic acid by approximately 25%. Similar to lovastatin, lifibrol had no effect on the synthesis of sterols from [14C]-mevalonic acid. Lifibrol did not inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Instead, cholesterol synthesis inhibition by lifibrol was entirely accounted for by competitive inhibition of HMG-CoA synthase. Lifibrol enhanced the cellular binding, uptake, and degradation of LDL in cultured cells in a dose dependent fashion. The stimulation of LDL receptors was significantly stronger than expected from the effect of lifibrol on sterol synthesis. In parallel, lifibrol increased the amount of immunologically detectable receptor protein. Stimulation of LDL receptor mediated endocytosis was observed both in the presence and in the absence of cholesterol-containing lipoproteins. In the absence of an extracellular source of cholesterol, both lifibrol and lovastatin induced microsomal HMG-CoA reductase. Co-incubation with LDL was sufficient to suppress the lifibrol mediated increase in reductase activity, indicating that lifibrol does not affect the production of the non-sterol derivative(s) which are thought to regulate HMG-CoA reductase activity at the post-transcriptional level. Considered together, the data suggest that the hypolipidemic action of lifibrol may, at least in part, be mediated by sterol-independent stimulation of the LDL receptor pathway. A potential advantage of lifibrol is that therapeutic concentrations do not interfere with the production of mevalonate which is required not only to synthesize sterols but also as a precursor of electron transport moieties, glycoproteins and farnesylated proteins.
Atherosclerosis 2000 Nov
PMID:The effects of lifibrol (K12.148) on the cholesterol metabolism of cultured cells: evidence for sterol independent stimulation of the LDL receptor pathway. 1105 1

Hepatic lipase (HL) not only plays an important role in plasma lipoprotein transport, but may also affect intracellular lipid metabolism. We hypothesize that HL expression is regulated as an integral part of intracellular lipid homeostasis. Addition of oleate (1 mM) to HepG2 cells increased HL secretion to 134+/-14% of control (p<0.02), and increased the transcriptional activity of a 698-bp HL promoter-reporter construct two-fold. Atorvastatin (10 microM) abolished the oleate stimulation. The transcriptional activity of a sterol-regulatory-element binding protein (SREBP)-sensitive HMG-CoA synthase promoter construct was reduced 50% by oleate, and increased 2-3-fold by atorvastatin. Co-transfection with an SREBP-2 expression vector reduced HL promoter activity and increased HMG-CoA synthase promoter activity. Upstream stimulatory factors (USF) are also implicated in maintenance of lipid homeostasis. Co-transfection with a USF-1 expression vector stimulated HL promoter activity 4-6-fold. The USF-stimulated HL promoter activity was not further enhanced by oleate, but almost completely prevented by atorvastatin or co-transfection with the SREBP-2 vector. Opposite regulation by USF-1 and SREBP-2 was also observed with a 318-bp HL promoter construct that lacks potential SRE-like and E-box binding motifs. We conclude that the opposite regulation of HL expression by fatty acids and statins is mediated via SREBP, possibly through interaction with USF.
Atherosclerosis 2005 Mar
PMID:Sterol-regulatory-element binding protein inhibits upstream stimulatory factor-stimulated hepatic lipase gene expression. 1572 Oct 10