Tracking fatty acid kinetics in distinct lipoprotein fractions in vivo: a novel high-throughput approach for studying dyslipidemia in rodent models

McLaren, David G.; Wang, Sheng Ping; Stout, Steven J.; Xie, Dan; Miller, Paul L.; Mendoza, Vivienne; Rosa, Raymond; Castro-Perez, José; Previs, Stephen F.; Johns, Douglas G.; Roddy, Thomas P.

doi:10.1194/jlr.d030791

Cited by 13 publications

(7 citation statements)

References 15 publications

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“…To determine whether a reduction in VLDL secretion contributed to the reduced plasma lipid levels, the TG production rate following intravenous administration of [ 13 C 18 ]oleic acid was measured. We have previously demonstrated using this protocol in mice that the majority of newly made TG appearing in plasma is contained in VLDL and thus measurements made in total plasma should be a reasonable surrogate to determine VLDL-TG production ( 27 ). Treatment with m-Scap-1 siRNA resulted in a dose-responsive reduction in the appearance of newly made TG in plasma and was most dramatic at 0.5 mg/kg dose ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Dose-dependent effects of siRNA-mediated inhibition of SCAP on PCSK9, LDLR, and plasma lipids in mouse and rhesus monkey

Jensen

Tadin‐Strapps

Wang

et al. 2016

Journal of Lipid Research

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SREBP cleavage-activating protein (SCAP) is a key protein in the regulation of lipid metabolism and a potential target for treatment of dyslipidemia. SCAP is required for activation of the transcription factors SREBP-1 and -2. SREBPs regulate the expression of genes involved in fatty acid and cholesterol biosynthesis, and LDL-C clearance through the regulation of LDL receptor (LDLR) and PCSK9 expression. To further test the potential of SCAP as a novel target for treatment of dyslipidemia, we used siRNAs to inhibit hepatic SCAP expression and assess the effect on PCSK9, LDLR, and lipids in mice and rhesus monkeys. In mice, robust liver Scap mRNA knockdown (KD) was achieved, accompanied by dose-dependent reduction in SREBP-regulated gene expression, de novo lipogenesis, and plasma PCSK9 and lipids. In rhesus monkeys, over 90% SCAP mRNA KD was achieved resulting in approximately 75, 50, and 50% reduction of plasma PCSK9, TG, and LDL-C, respectively. Inhibition of SCAP function was demonstrated by reduced expression of SREBP-regulated genes and de novo lipogenesis. In conclusion, siRNA-mediated inhibition of SCAP resulted in a significant reduction in circulating PCSK9 and LDL-C in rodent and primate models supporting SCAP as a novel target for the treatment of dyslipidemia.

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Section: Resultsmentioning

confidence: 99%

Dose-dependent effects of siRNA-mediated inhibition of SCAP on PCSK9, LDLR, and plasma lipids in mouse and rhesus monkey

Jensen

Tadin‐Strapps

Wang

et al. 2016

Journal of Lipid Research

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“…Lipoprint gel electrophoresis was used to separate VLDL, LDL + IDL, and HDL from a separate, 25 l aliquot of plasma using LDL gel kits (Quantimetrix, Redondo Beach, CA). Gel bands containing the isolated lipoprotein fractions were excised and homogenized in PBS buffer for subsequent lipid extraction as previously described ( 14 ). The concentrations of all isotopomers of TG52:2 (M 0 , M 11 , M 18 , M 22 , and M 36 ) were determined in each lipoprotein fraction using an LC/MS method that has been described elsewhere ( 24 ).…”

Section: Methodsmentioning

confidence: 99%

“…Plasma time) of TG in specifi c lipoprotein compartments at one or more physiological steady states (10)(11)(12)(13). Using these methods as a starting point, we previously demonstrated the techniques necessary to characterize TG transfer between lipoprotein compartments in vivo using C57Bl/6 wild-type mice (which lack CETP) and natural fl anking region (NFR)-CETP-transgenic mice ( 14 ). Clear differences in the kinetics of TG appearance in HDL were observed between these two extreme conditions (i.e., in the absence and presence of CETP).…”

Section: Effects Of Anacetrapib On Hdl-tg Fl Ux In Vivomentioning

confidence: 99%

Evaluation of CETP activity in vivo under non-steady-state conditions: influence of anacetrapib on HDL-TG flux

McLaren

Previs

Phair³

et al. 2016

Journal of Lipid Research

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This article is available online at http://www.jlr.org ( 3,4 ) identifi ed a single lipid transfer protein in human plasma that was capable of carrying out this apparent heterolipid exchange and that is known today as cholesteryl ester transfer protein (CETP). In these and other reports, the exchange of HDL-CE for apoB-lipoprotein-TG was evaluated in vitro using lipoproteins containing radiolabeled CE and/or TG. Using this approach, the effects of donor and acceptor lipid composition ( 4 ), hypercholesterolemia ( 5 ), and many other parameters on CETP-mediated neutral lipid exchange have been assessed. The CETPmediated exchange of neutral lipids between lipoproteins in vivo has also been studied ( 6-9 ). In such cases, the experimental protocol typically involves injection of lipoprotein particles, radiolabeled with CE either in vitro or in vivo, into subjects followed by collection of blood samples for further analysis. Transfer activity is then evaluated by measuring the loss of enrichment from the donor particle and increase in enrichment of acceptor particles that were isolated from the postinjection blood samples.We hypothesized that the movement of TG from apoB lipoproteins to HDL could serve as a quantifi able activity measurement in vivo that would not require prior isolation and reinjection of donor particles. As noted, although the protein is commonly referred to as "cholesteryl ester transfer protein," the transfer of TG also occurs; this should allow an experimental protocol to be designed based on well-characterized methods for labeling TGs in free-living subjects. Lipoprotein TG kinetics have been studied for at least 30 years using both radioisotopes and stable isotopes to label the fatty acid precursors or the glycerol backbone. In the majority of cases, the goals of such studies have been determination of the fl ux (mass per unit Nichols and Smith ( 1 ) were the fi rst to observe that cholesteryl esters (CEs) could be transferred from HDL to apoB-containing lipoproteins in exchange for TG in incubated human serum, a fi nding later confi rmed by Hopkins and Barter ( 2 ). Subsequent investigations by Morton et al.

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“…Plasma levels of total cholesterol and free cholesterol were determined using a Cholesterol Quantification kit from Sigma (Sigma, St. Louis, MO, USA). Lipoproteins were separated from 25 µL of citrate-anticoagulated plasma using a photopolymerized loading gel stained with Sudan black dye (Lipoprint, Los Angeles, CA, USA) [ 49 ]. The samples were subjected to electrophoresis for 60 min at 3 mA per gel tube, set at a maximum delivery of 500 V. Bands were identified on the basis of the migration distance, according to the instructions of the manufacturer.…”

Section: Methodsmentioning

confidence: 99%

Selective HDL-Raising Human Apo A-I Gene Therapy Counteracts Cardiac Hypertrophy, Reduces Myocardial Fibrosis, and Improves Cardiac Function in Mice with Chronic Pressure Overload

Amin

Muthuramu

Aboumsallem

et al. 2017

IJMS

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Epidemiological studies support an independent inverse association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. The effect of selective HDL-raising adeno-associated viral serotype 8-human apolipoprotein (apo) A-I (AAV8-A-I) gene transfer on cardiac remodeling induced by transverse aortic constriction (TAC) was evaluated in C57BL/6 low-density lipoprotein receptor-deficient mice. Septal wall thickness and cardiomyocyte cross-sectional area were reduced by 16.5% (p < 0.001) and by 13.8% (p < 0.01), respectively, eight weeks after TAC in AAV8-A-I mice (n = 24) compared to control mice (n = 39). Myocardial capillary density was 1.11-fold (p < 0.05) higher and interstitial cardiac fibrosis was 45.3% (p < 0.001) lower in AAV8-A-I TAC mice than in control TAC mice. Lung weight and atrial weight were significantly increased in control TAC mice compared to control sham mice, but were not increased in AAV8-A-I TAC mice. The peak rate of isovolumetric contraction was 1.19-fold (p < 0.01) higher in AAV8-A-I TAC mice (n = 17) than in control TAC mice (n = 29). Diastolic function was also significantly enhanced in AAV8-A-I TAC mice compared to control TAC mice. Nitro-oxidative stress and apoptosis were significantly reduced in the myocardium of AAV8-A-I TAC mice compared to control TAC mice. In conclusion, selective HDL-raising human apo A-I gene transfer potently counteracts the development of pressure overload-induced cardiomyopathy.

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Tracking fatty acid kinetics in distinct lipoprotein fractions in vivo: a novel high-throughput approach for studying dyslipidemia in rodent models

Cited by 13 publications

References 15 publications

Dose-dependent effects of siRNA-mediated inhibition of SCAP on PCSK9, LDLR, and plasma lipids in mouse and rhesus monkey

Dose-dependent effects of siRNA-mediated inhibition of SCAP on PCSK9, LDLR, and plasma lipids in mouse and rhesus monkey

Evaluation of CETP activity in vivo under non-steady-state conditions: influence of anacetrapib on HDL-TG flux

Selective HDL-Raising Human Apo A-I Gene Therapy Counteracts Cardiac Hypertrophy, Reduces Myocardial Fibrosis, and Improves Cardiac Function in Mice with Chronic Pressure Overload

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