- Regulation of liver X receptor target genes by 22-functionalized oxysterols. Synthesis, in silico and in vitro evaluations
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The endogenous oxysterol 22(R)-hydroxycholesterol (22RHC, 1) is an LXR agonist which upregulates genes of critical involvement in human cholesterol- and lipid metabolism. In contrast, its synthetic epimer 22(S)-hydroxycholesterol (22SHC, 8) has shown specific antagonistic effects in recent studies, avoiding unwanted side effects provided by potent LXR agonists. In terms of LXR modulation, the aim of this study was to compare 22SHC (8), 22RHC (1) and synthesized ligands with keto- and amide functionality in the 22nd position of the cholesterol scaffold. 22SHC (8) and 22RHC (1) performed as expected while 22-ketocholesterol (22KC, 10) revealed an attractive in vitro profile for further investigation in terms of anti-atherosclerotic properties as selective upregulation of the ATP-binding cassette transporter ABCA1 was observed. A new synthesized amide derivate, Fernholtz cyclohexylamide (13) was shown to reduce lipogenesis in a dose-responsive manner and abolish the effect of the potent LXR agonist T0901317 when administered simultaneously.
- Viktorsson, Elvar ?rn,Gabrielsen, Mari,Kumarachandran, Nugalya,Sylte, Ingebrigt,Rongved, P?l,?strand, Ove Alexander H?gmoen,Kase, Eili Tranheim
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- Chirality Transfer in Stereoselective Synthesis. A Highly Stereocontrolled Synthesis of 22-Hydroxylated Steroid Side Chains via the -Wittig Rearrangement
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An efficient approach toward 22-oxygenated steroid side chains has been accomplished utilizing the -Wittig rearrangement of the dianion derived from the (E)-17(20)-ethylidene-16α-(carboxymethyl)oxy steroid.
- Koreeda, Masato,Ricca, Daniel J.
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- Cytotoxicity and suppression of immunoglobulin production against human Namalwa cells caused by oxidized cholesterol
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The effects of oxidized cholesterols on proliferation and IgM production of human lymphoblastoid Namalwa cells were examined. An oxidized cholesterol mixture, in contrast to cholesterol, was a potent cytotoxin to Namalwa cells. Among oxidized cholesterols examined, 25-hydroxycholesterol was the most cytotoxic. However, no oxidized cholesterol examined suppressed IgM production, although cholestanetriol and 7-ketocholesterol did suppress it. Thus, oxidized cholesterols are cytotoxic to lymphocytes, while the influence on the immunoglobulin production may be marginal.
- Osada, Kyoichi,Kodama, Takehiro,Matsuo, Noritaka,Yamada, Koji,Sugano, Michihiro
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p. 1362 - 1364
(2007/10/03)
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- Stereocontrolled Synthesis of (22R)-22-Hydroxycholesterol Guided by α-Silyl Radical Stabilization
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The synthesis of (22R)-22-hydroxycholesterol, featuring formation of three contiguous chiral centers (C-17, 20, and 22) in a single step by the use of a 6-endo α-silyl radical-mediated cyclization is presented.Additionally, an interesting protiodesilyatio
- Koreeda, Masato,George, Irene A.
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- 22-Hydroxycholesterol Derivatives as HMG CoA Reductase Suppressors and Serum Cholesterol Lowering Agents
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A series of 22-hydroxycholesterol derivatives with a modified side chain terminus was prepared.These agents were evaluated in vitro and in vivo for their ability to suppress HMG CoA reductase, the rate-limiting enzyme of cholesterol biosynthesis.In tissue culture assays, 22-hydroxycholesterol as well as the side chain modified analogues were potent inhibitors of HMG CoA reductase.However, only those sterols with a modified side chain terminus were effective suppressors of liver reductase whene administered ig to rats. 22-Hydroxy-25-methylcholesterol (4a) and 25-fluoro-22-hydroxycholesterol (15a) significantly lowered serum cholesterol levels when administered ig to primates; 25-chloro-22-hydroxycholesterol (15b) and the analogue with a cyclopropyl terminus, 20b, were ineffective.The cholesterol-lowering sterols did not significantly alter lipoprotein levels; however, the two compounds have been shown to inhibit acyl-coenzyme A:cholesterol-transferase (ACAT) in tissue culture studies
- Chorvat, Robert J.,Desai, Bipin N.,Radak, Suzanne Evans,McLaughlin, Kathleen T.,Miller, James E.,et al.
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p. 194 - 200
(2007/10/02)
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- Stereoselective Synthesis of Plant Growth-promoting Steroids, Brassinolide, Castasterone, Typhasterol, and Their 28-Nor Analogues
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Plant growth-promoting steroids, brassinolide (1a), (22R,23R,24S)-2α,3α,22,23-tetrahydroxy-B-homo-7-oxa-5α-ergostan-6-one, castasterone (2a), (22R,23R,24S)-2α,3α,22,23-tetrahydroxy-5α-ergostan-6-one, 28-norbrassinolide (1b), (22R,23R)-2α,3α,22,23-tetrahydroxy-B-homo-7-oxa-5α-cholestan-6-one, brassinone (2b), (22R,23R)-2α,3α,22,23-tetrahydroxy-5α-cholestan-6-one, and typhasterol (2c), (22R,23R,24S)-3α,22,23-trihydroxy-5α-ergostan-6-one, have been stereoselectively synthesized.These steroids show very strong biological activities in three different kinds of bioassays.
- Takatsuto, Suguru,Yazawa, Naoto,Ishiguro, Masaji,Morisaki, Masuo,Ikekawa, Nobuo
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p. 139 - 146
(2007/10/02)
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- Synthesis of Brassinolide, a Steroidal Lactone with Plant-growth Promoting Activity
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Brassinolide, a plant-growth promoter isolated from rape pollen, was stereoselectively synthesized from dinorcholenic acid.
- Ishiguro, Masaji,Takatsuto, Suguru,Morisaki, Masuo,Ikekawa, Nobuo
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p. 962 - 964
(2007/10/02)
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- Inhibition of sterol synthesis in cultured mouse cells by cholesterol derivatives oxygenated in the side chain
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Sterols derived from cholesterol by hydroxylation of the side chain in the 20α, 22α, 22β, or 25 position inhibited sterol synthesis from acetate and depressed the level of 3 hydroxy 3 methylglutaryl CoA reductase (EC 1.1.1.34) activity in primary cultures of mouse fetal liver cells and in L cell cultures. Rates of acetate metabolism to fatty acids and CO2, and rates of RNA and protein synthesis were not affected. Following the addition of the most potent inhibitors of the group, 25 hydroxycholesterol and 20α hydroxycholesterol, to L cell cultures the enzyme activity diminished to one half of the original amount within a period of 1 to 1.3 hr. Inhibitory potency was influenced by the location of the hydroxyl function on the side chain, by the completeness of the side chain, and by the introduction of a third functional group into the molecule. (21 references.)
- Kandutsch,Chen
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p. 6057 - 6061
(2007/10/13)
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