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Chen Y, Berejnaia O, Liu J, Wang SP, Daurio NA, Yin W, Mayoral R, Petrov A, Kasumov T, Zhang GF, Previs SF, Kelley DE, McLaren DG. Quantifying ceramide kinetics in vivo using stable isotope tracers and LC-MS/MS. Am J Physiol Endocrinol Metab 2018; 315:E416-E424. [PMID: 29509438 DOI: 10.1152/ajpendo.00457.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Numerous studies have implicated dyslipidemia as a key factor in mediating insulin resistance. Ceramides have received special attention since their levels are inversely associated with normal insulin signaling and positively associated with factors that are involved in cardiometabolic disease. Despite the growing literature surrounding ceramide biology, there are limited data regarding the activity of ceramide synthesis and turnover in vivo. Herein, we demonstrate the ability to measure ceramide kinetics by coupling the administration of [2H]water with LC-MS/MS analyses. As a "proof-of-concept" we determined the effect of a diet-induced alteration on ceramide flux; studies also examined the effect of myriocin (a known inhibitor of serine palmitoyltransferase, the first step in sphingosine biosynthesis). Our data suggest that one can estimate ceramide synthesis and draw conclusions regarding the source of fatty acids; we discuss caveats in regards to method development in this area.
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Affiliation(s)
- Ying Chen
- MRL, Merck & Co., Inc., Kenilworth, New Jersey
| | | | - Jinqi Liu
- MRL, Merck & Co., Inc., Kenilworth, New Jersey
| | | | | | - Wu Yin
- MRL, Merck & Co., Inc., Kenilworth, New Jersey
| | | | | | - Takhar Kasumov
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - Guo-Fang Zhang
- Division of Endocrinology, Metabolism and Nutrition, Duke Molecular Physiology Institute, and Department of Medicine, Duke University , Durham, North Carolina
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Pan Y, Zhou H, Mahsut A, Rohm RJ, Berejnaia O, Price O, Chen Y, Castro-Perez J, Lassman ME, McLaren D, Conway J, Jensen KK, Thomas T, Reyes-Soffer G, Ginsberg HN, Gutstein DE, Cleary M, Previs SF, Roddy TP. Static and turnover kinetic measurement of protein biomarkers involved in triglyceride metabolism including apoB48 and apoA5 by LC/MS/MS. J Lipid Res 2014; 55:1179-87. [PMID: 24694356 DOI: 10.1194/jlr.d047829] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Indexed: 11/20/2022] Open
Abstract
LC/MS quantification of multiple plasma proteins that differ by several orders of magnitude in concentration from a single sample is challenging. We present a strategy that allows the simultaneous determination of the concentration and turnover kinetics of higher and lower abundant proteins from a single digestion mixture. Our attention was directed at a cluster of proteins that interact to affect the absorption and interorgan lipid trafficking. We demonstrate that apos involved in TG metabolism such as apoC2, C3, E, and A4 (micromolar concentration), and apoB48 and apoA5 (single-digit nanomolar concentration) can be quantified from a single digestion mixture. A high degree of correlation between LC/MS and immunobased measurements for apoC2, C3, E, and B48 was observed. Moreover, apoA5 fractional synthesis rate was measured in humans for the first time. Finally, the method can be directly applied to studies involving nonhuman primates because peptide sequences used in the method are conserved between humans and nonhuman primates.
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Affiliation(s)
- Yi Pan
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Haihong Zhou
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Ablatt Mahsut
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Rory J Rohm
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Olga Berejnaia
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Olga Price
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - Ying Chen
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | | | | | - David McLaren
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | - James Conway
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | | | | | | | | | | | - Michele Cleary
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
| | | | - Thomas P Roddy
- Merck Research Laboratories, Merck & Co. Inc., Kenilworth, NJ
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Wang L, Wismer MK, Racine F, Conway D, Giacobbe RA, Berejnaia O, Kath GS. Development of an integrated semi-automated system for in vitro pharmacodynamic modelling. J Antimicrob Chemother 2008; 62:1070-7. [PMID: 18647747 DOI: 10.1093/jac/dkn294] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The aim of this study was to develop an integrated system for in vitro pharmacodynamic modelling of antimicrobials with greater flexibility, easier control and better accuracy than existing in vitro models. METHODS Custom-made bottle caps, fittings, valve controllers and a modified bench-top shaking incubator were used. A temperature-controlled automated sample collector was built. Computer software was developed to manage experiments and to control the entire system including solenoid pinch valves, peristaltic pumps and the sample collector. The system was validated by pharmacokinetic simulations of linezolid 600 mg infusion. The antibacterial effect of linezolid against multiple Staphylococcus aureus strains was also studied in this system. RESULTS An integrated semi-automated bench-top system was built and validated. The temperature-controlled automated sample collector allowed unattended collection and temporary storage of samples. The system software reduced the labour necessary for many tasks and also improved the timing accuracy for performing simultaneous actions in multiple parallel experiments. The system was able to simulate human pharmacokinetics of linezolid 600 mg intravenous infusion accurately. A pharmacodynamic study of linezolid against multiple S. aureus strains with a range of MICs showed that the required 24 h free drug AUC/MIC ratio was approximately 30 in order to keep the organism counts at the same level as their initial inoculum and was about > or = 68 in order to achieve > 2 log(10) cfu/mL reduction in the in vitro model. CONCLUSIONS The integrated semi-automated bench-top system provided the ability to overcome many of the drawbacks of existing in vitro models. It can be used for various simple or complicated pharmacokinetic/pharmacodynamic studies efficiently and conveniently.
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Affiliation(s)
- Liangsu Wang
- Department of Infectious Disease Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, NJ 07065, USA.
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