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A series of cycloalkyl-substituted oxo-alkanedicarboxylic acids have been prepared by the TosMIC methodology departing from haloalkyl-substituted cycloalkylcarboxylic esters. cyclopropyl derivatives showed IC50 activity in the 0.3–1.0 μM range on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes, and they showed lipid-regulating properties when tested in vivo in female obese Zucker fatty rats.

Keto-substituted hydrocarbons with 11-19 methylene and bis-terminal hydroxyl and carboxyl groups have been synthesized and evaluated in both in vivo and in vitro assays for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in obese female Zucker fatty rats [Crl:(ZUC)-faBR] following 1 and 2 weeks of oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ketone functionality and the gem dimethyl or methyl/aryl substituents. Furthermore, biological activity was found to be greatest in both in vivo and in vitro assays for the tetramethyl-substituted keto diacids and diols (e.g., 10c, 10g, 14c), and the least active were shown to be the bis(arylmethyl) derivatives (e.g., 10e, 10f, 14f). Compound 14c dose-dependently elevated HDL-cholesterol, reduced triglycerides, and reduced NEFA, with a minimum effective dose of 30 mg/kg/day. Compound 1 g dose-dependently modified non-HDL-cholesterol, triglycerides, and nonesterified fatty acids, with a minimum effective dose of 10 mg/kg/day. At this dose, compound 10g elevated HDL-cholesterol levels 2-3 times higher than pretreatment levels, and a dose-dependent reduction of fasting insulin and glucose levels was observed.

Long hydrocarbon chain ethers with bis-terminal hydroxyl or carboxyl groups have been synthesized and evaluated for their potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid and glycemic variables in female obese Zucker fatty rats following 1 and 2 weeks of daily oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the central ether functionality and the gem dimethyl or methyl/aryl substituents. Biological activity was found to be greatest for tetramethyl-substituted ether diols (e.g., 28 and 31), while bis(arylmethyl) derivatives (e.g., 10, 11, and 27), diethers (e.g., 49, 50, and 56), and diphenyl ethers (e.g., 35 and 36) were the least active. For the most biologically active compound 28, we observed as much as a 346% increase in serum HDL-cholesterol and a 71% reduction in serum triglycerides at the highest dose administered (100 mg/kg) after 2 weeks of treatment. For compound 31 we observed a 69% reduction in non-HDL-cholesterol, accompanied by a 131% increase in HDL-cholesterol and an 84% reduction in serum triglycerides under the same treatment conditions.

We have identified a novel omega-hydroxy-alkanedicarboxylic acid, ESP 55016, that favorably alters serum lipid variables in obese female Zucker (fa/fa) rats. ESP 55016 reduced serum non-HDL-cholesterol (non-HDL-C), triglyceride, and nonesterified fatty acid levels while increasing serum HDL-C and beta-hydroxybutyrate levels in a dose-dependent manner. ESP 55016 reduced fasting serum insulin and glucose levels while also suppressing weight gain. In primary rat hepatocytes, ESP 55016 increased the oxidation of [(14)C]palmitate in a dose- and carnitine palmitoyl transferase-I (CPT-I)-dependent manner. Furthermore, in primary rat hepatocytes and in vivo, ESP 55016 inhibited fatty acid and sterol synthesis. The "dual inhibitor" activity of ESP 55016 was unlikely attributable to the activation of the AMP-activated protein kinase (AMPK) pathway because AMPK and acetyl-CoA carboxylase (ACC) phosphorylation states as well as ACC activity were not altered by ESP 55016. Further studies indicated the conversion of ESP 55016 to a CoA derivative in vivo. ESP 55016-CoA markedly inhibited the activity of partially purified ACC. The activity of partially purified HMG-CoA reductase was not altered by the xenobiotic-CoA. These data suggest that ESP 55016-CoA favorably alters lipid metabolism in a model of diabetic dyslipidemia in part by initially inhibiting fatty acid and sterol synthesis plus enhancing the oxidation of fatty acids through the ACC/malonyl-CoA/CPT-I regulatory axis.

To induce atherogenesis in mice, a high fat (HF) diet is supplemented with cholic acid (CA), which increases apoB-containing particles and lower apoA-I-containing particles. HF diet without CA increases levels of both HDL and LDL, suggesting that CA may be responsible for the elevation of LDL and lowering of HDL. The mechanism of dietary CA-induced lowering of apoA-I-containing particles has recently been reported. In this study, we examined the mechanism of CA- and HF-induced elevation of apoB-containing lipoproteins in mice. Mice were fed the following four diets: control chow (C), high fat high cholesterol, (HF), control and 0.5% cholate (CA), and HF + CA. Dietary CA increased the plasma levels of apoB-containing particles by ∼2-fold when compared to control; VLDL levels increased 2-fold, and LDL levels increased 1.3-fold. On HF diet, VLDL increased by 1.4-fold, and LDL by 2-fold, suggesting that CA and HF-induced increases of apoB-containing particles occurred by different mechanisms. We investigated the potential mechanisms regulating plasma levels of apoB in CA- and HF-fed mice. Although hepatic apoB mRNA levels did not change on CA diet, apoB-100 mRNA increased relative to B-48 as a result of decreased editing of apoB mRNA. Measurements of hepatic LDL receptor mRNA suggested that CA diet down-regulated LDL receptor mRNA, possibly by increasing the levels of hepatic cholesterol. Since plasma and hepatic vitamin E levels did not show significant changes on CA-containing diets, it suggests that dietary CA did not act by increasing the absorption of dietary fat. Hepatic lipase, known to modulate plasma levels of apoB-containing particles, did not show changes in CA- or HF-fed mice. Taken together, these results suggest that dietary CA increased apoB-containing particles both in chow-fed and fat-fed mice by enhancing the relative production of apoB-100, and also by reducing LDL receptor-mediated clearance of apoB-containing particles. Thus, dietary cholate modulates plasma levels of apoB primarily by posttranscriptional mechanisms. © 2001 Elsevier Science Ltd. All rights reserved.

A series of long (11-15) hydrocarbon chain diols and diacids with various central functional groups and terminal gem-dimethyl or -methyl/aryl substituents was synthesized and evaluated in both in vivo and in vitro assays for its potential to favorably alter lipid disorders including metabolic syndrome. Compounds were assessed for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes, as well as for their effects on lipid and glycemic variables in obese female Zucker fatty rats, Crl:(ZUC)-faBR. The most active compounds were hydroxyl-substituted symmetrical diacids and diols with a 13-atom chain and terminal gem-dimethyl substituents. Furthermore, biological activity was enhanced by central substitution with O, C=O, S, S=O compared to the methylene analogues and was diminished for compounds with central functional groups such as carbamate, ester, urea, acetylmethylene, and hydroxymethylene.

Tumor necrosis factor (TNF) is secreted by macrophages in response to various stimuli and blocks lipid accumulation during the conversion of preadipocytes to adipocytes in culture. In the present report, we investigate the effect of recombinant TNF on the expression of acetyl-coenzyme-A (CoA) carboxylase, the rate-limiting enzyme for long-chain fatty acid biosynthesis. We used a preadipocyte cell line, 30A-5, derived from 10T1/2 mouse fibroblasts after treatment with 5-azacytidine. Treatment of the preadipocyte cell line with dexamethasone and insulin triggers the conversion of these cells to mature adipocytes as evidenced by the accumulation of lipid. The mRNA and enzyme levels of acetyl-CoA carboxylase as well as the enzyme activity increase markedly during the conversion process. TNF prevents the conversion of preadipocytes to adipocytes with a concomitant inhibition in the accumulation of acetyl-CoA carboxylase mRNA and decrease in enzyme activity. This observed reduction in acetyl-CoA carboxylase mRNA levels is reversible upon removal of TNF. Acetyl-CoA carboxylase mRNA levels and enzyme activity also decrease when fully differentiated adipocytes are exposed to TNF but to a much lesser extent. These results suggest that TNF affects de novo lipid synthesis in part by altering the mRNA levels of acetyl-CoA carboxylase.

We measured acetyl-CoA carboxylase mRNA levels in various tissues of the rat under different nutritional and hormonal states using a cDNA probe. We surveyed physiological conditions which are known to alter carboxylase activity, and thus fatty acid synthesis, to determine whether changes in the levels of carboxylase mRNA are involved. The present studies include the effects of fasting and refeeding, diabetes and insulin, and lactation on carboxylase mRNA levels. Northern blot analysis of liver RNA revealed that fasting followed by refeeding animals a fat-free (high carbohydrate) diet dramatically increased the amount of carboxylase mRNA compared to the fasted condition. These changes in the level of mRNA correspond to changes in the activity and amount of acetyl-CoA carboxylase. Acetyl-CoA carboxylase mRNA levels in epididymal fat tissue decreased upon fasting and increased to virtually normal levels after 72 h of refeeding, closely resembling the liver response. The amount of acetyl-CoA carboxylase mRNA decreased markedly in epididymal fat tissue of diabetic rats as compared to nondiabetic animals. However, 6 h after injection of insulin the mRNA level returned to that of the nondiabetic animals. Gestation and lactation also affected the levels of carboxylase mRNA in both liver and mammary gland. Maximum induction in both tissues occurred 5 days postpartum. These studies suggest that these diverse physiological conditions affect fatty acid synthesis in part by altering acetyl-CoA carboxylase gene expression.

Poly(A)+ RNA from lactating rat mammary glands was fractionated according to size by isokinetic sucrose gradient centrifugation to obtain a fraction enriched for acetyl-CoA carboxylase. In vitro translation of this RNA preparation yielded apparent full-length acetyl-CoA carboxylase with a molecular weight of 260,000. The synthesized protein was identified as acetyl-CoA carboxylase by specific immunoprecipitation. Tests with antiserum to fatty acid synthetase, revealed that the fractions containing acetyl-CoA carboxylase mRNA also contained mRNA for fatty acid synthetase; both of these mRNAs were approximately 10 kb. Fatty acid synthetase with a molecular weight of 250,000 was synthesized. Using an in vitro rabbit reticulocyte lysate translation system, we have shown that the amount of translatable acetyl-CoA carboxylase mRNA increases during lactation. On the fifth day postpartum the level of translatable acetyl-CoA carboxylase mRNA increased to a peak level seven times that on the day of parturition.