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Mucinski JM, McCaffrey JM, Rector RS, Kasumov T, Parks EJ. Relationship between hepatic and mitochondrial ceramides: A novel in vivo method to track ceramide synthesis. J Lipid Res 2023; 64:100366. [PMID: 37028768 DOI: 10.1016/j.jlr.2023.100366] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
Ceramides (CERs) are key intermediate sphingolipids implicated in contributing to mitochondrial dysfunction and the development of multiple metabolic conditions. Despite the growing evidence of CERs role in disease risk, kinetic methods to measure CER turnover are lacking, particularly using in vivo models. The utility of orally-administered 13C3, 15N L-serine, dissolved in drinking water, was tested to quantify CER 18:1/16:0 synthesis in 10 week-old male and female C57Bl/6 mice. To generate isotopic labeling curves, animals consumed either a control (CD) or high fat diet (HFD; n=24/diet) for two weeks and varied in the duration of the consumption of serine-labeled water (0, 1, 2, 4, 7, or 12 days; n=four animals/day/diet). Unlabeled and labeled hepatic and mitochondrial CERs were quantified using liquid chromatography tandem mass spectrometry. Total hepatic CER content did not differ between the two diet groups while total mitochondrial CERs increased with HFD feeding (60%, P<0.001). Within hepatic and mitochondrial pools, HFD induced greater saturated CER concentrations (P<0.05) and significantly elevated absolute turnover of 16:0 mitochondrial CER (mitochondria: 59%, P<0.001 versus liver: 15%, P=0.256). The data suggest cellular redistribution of CERs due to the HFD. These data demonstrate that a two-week HFD alters the turnover and content of mitochondrial CERs. Given the growing data on CERs contributing to hepatic mitochondrial dysfunction and the progression of multiple metabolic diseases, this method may now be used to investigate how CER turnover is altered in these conditions.
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The FKBP51 Inhibitor SAFit2 Restores the Pain-Relieving C16 Dihydroceramide after Nerve Injury. Int J Mol Sci 2022; 23:ijms232214274. [PMID: 36430751 PMCID: PMC9695264 DOI: 10.3390/ijms232214274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
Neuropathic pain is a pathological pain state with a broad symptom scope that affects patients after nerve injuries, but it can also arise after infections or exposure to toxic substances. Current treatment possibilities are still limited because of the low efficacy and severe adverse effects of available therapeutics, highlighting an emerging need for novel analgesics and for a detailed understanding of the pathophysiological alterations in the onset and maintenance of neuropathic pain. Here, we show that the novel and highly specific FKBP51 inhibitor SAFit2 restores lipid signaling and metabolism in nervous tissue after nerve injury. More specifically, we identify that SAFit2 restores the levels of the C16 dihydroceramide, which significantly reduces the sensitization of the pain-mediating TRPV1 channel and subsequently the secretion of the pro-inflammatory neuropeptide CGRP in primary sensory neurons. Furthermore, we show that the C16 dihydroceramide is capable of reducing acute thermal hypersensitivity in a capsaicin mouse model. In conclusion, we report for the first time the C16 dihydroceramide as a novel and crucial lipid mediator in the context of neuropathic pain as it has analgesic properties, contributing to the pain-relieving properties of SAFit2.
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Salvador AF, Shyu CR, Parks EJ. Measurement of lipid flux to advance translational research: evolution of classic methods to the future of precision health. EXPERIMENTAL & MOLECULAR MEDICINE 2022; 54:1348-1353. [PMID: 36075949 PMCID: PMC9534914 DOI: 10.1038/s12276-022-00838-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/22/2022] [Accepted: 07/12/2022] [Indexed: 02/08/2023]
Abstract
Over the past 70 years, the study of lipid metabolism has led to important discoveries in identifying the underlying mechanisms of chronic diseases. Advances in the use of stable isotopes and mass spectrometry in humans have expanded our knowledge of target molecules that contribute to pathologies and lipid metabolic pathways. These advances have been leveraged within two research paths, leading to the ability (1) to quantitate lipid flux to understand the fundamentals of human physiology and pathology and (2) to perform untargeted analyses of human blood and tissues derived from a single timepoint to identify lipidomic patterns that predict disease. This review describes the physiological and analytical parameters that influence these measurements and how these issues will propel the coming together of the two fields of metabolic tracing and lipidomics. The potential of data science to advance these fields is also discussed. Future developments are needed to increase the precision of lipid measurements in human samples, leading to discoveries in how individuals vary in their production, storage, and use of lipids. New techniques are critical to support clinical strategies to prevent disease and to identify mechanisms by which treatments confer health benefits with the overall goal of reducing the burden of human disease. Personalized tracking of how lipid (fat) metabolism changes over time could lead to improvements in the diagnosis and treatment of several diseases. Elizabeth Parks and colleagues from the University of Missouri, Columbia, USA, discuss the ways in which researchers use stable isotope labeling to monitor the kinetics of fatty acids and other lipids in the body. Usually, lipid quantities are measured only at a single timepoint, however the tracking of lipid turnover over time provides further diagnostic information. Aided by new techniques such as high-throughput mass spectrometry and machine learning, researchers are now able to continuously map total lipid contents in individual patients. The transition of measurements of lipid flux from the research laboratory to the doctor’s office will likely play a role in a new era of precision medicine.
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Affiliation(s)
- Amadeo F Salvador
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, 65212, USA.,Department of Medicine, Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.,Department of Electrical Engineering and Computer Science, Institute for Data Science and Informatics, University of Missouri, Columbia, MO, 65211, USA
| | - Chi-Ren Shyu
- Department of Electrical Engineering and Computer Science, Institute for Data Science and Informatics, University of Missouri, Columbia, MO, 65211, USA
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, 65212, USA. .,Department of Medicine, Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.
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Satapati S, Downes DP, Metzger D, Shankaran H, Talukdar S, Zhou Y, Ren Z, Chen M, Lim YH, Hatcher NG, Wen X, Sheth PR, McLaren DG, Previs SF. Using measures of metabolic flux to align screening and clinical development: Avoiding pitfalls to enable translational studies. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:20-28. [PMID: 35058172 DOI: 10.1016/j.slasd.2021.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Screening campaigns, especially those aimed at modulating enzyme activity, often rely on measuring substrate→product conversions. Unfortunately, the presence of endogenous substrates and/or products can limit one's ability to measure conversions. As well, coupled detection systems, often used to facilitate optical readouts, are subject to interference. Stable isotope labeled substrates can overcome background contamination and yield a direct readout of enzyme activity. Not only can isotope kinetic assays enable early screening, but they can also be used to follow hit progression in translational (pre)clinical studies. Herein, we consider a case study surrounding lipid biology to exemplify how metabolic flux analyses can connect stages of drug development, caveats are highlighted to ensure reliable data interpretations. For example, when measuring enzyme activity in early biochemical screening it may be enough to quantify the formation of a labeled product. In contrast, cell-based and in vivo studies must account for variable exposure to a labeled substrate (or precursor) which occurs via tracer dilution and/or isotopic exchange. Strategies are discussed to correct for these complications. We believe that measures of metabolic flux can help connect structure-activity relationships with pharmacodynamic mechanisms of action and determine whether mechanistically differentiated biophysical interactions lead to physiologically relevant outcomes. Adoption of this logic may allow research programs to (i) build a critical bridge between primary screening and (pre)clinical development, (ii) elucidate biology in parallel with screening and (iii) suggest a strategy aimed at in vivo biomarker development.
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Affiliation(s)
- Santhosh Satapati
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Daniel P Downes
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA
| | - Daniel Metzger
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Harish Shankaran
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Saswata Talukdar
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Yingjiang Zhou
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Zhao Ren
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Michelle Chen
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Yeon-Hee Lim
- Merck & Co., Inc, 213 E. Grand Ave, South San Francisco, CA, 94080, USA
| | - Nathan G Hatcher
- Merck & Co., Inc, 770 Sumneytown Pike, West Point, PA, 19486, USA
| | - Xiujuan Wen
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA
| | - Payal R Sheth
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA
| | - David G McLaren
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA
| | - Stephen F Previs
- Merck & Co., Inc, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA.
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Zelnik ID, Volpert G, Viiri LE, Kauhanen D, Arazi T, Aalto-Setälä K, Laaksonen R, Futerman AH. Different rates of flux through the biosynthetic pathway for long-chain versus very-long-chain sphingolipids. J Lipid Res 2020; 61:1341-1346. [PMID: 32651186 PMCID: PMC7529049 DOI: 10.1194/jlr.ra120000984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The backbone of all sphingolipids (SLs) is a sphingoid long-chain base (LCB) to which a fatty acid is N-acylated. Considerable variability exists in the chain length and degree of saturation of both of these hydrophobic chains, and recent work has implicated ceramides with different LCBs and N-acyl chains in distinct biological processes; moreover, they may play different roles in disease states and possibly even act as prognostic markers. We now demonstrate that the half-life, or turnover rate, of ceramides containing diverse N-acyl chains is different. By means of a pulse-labeling protocol using stable-isotope, deuterated free fatty acids, and following their incorporation into ceramide and downstream SLs, we show that very-long-chain (VLC) ceramides containing C24:0 or C24:1 fatty acids turn over much more rapidly than long-chain (LC) ceramides containing C16:0 or C18:0 fatty acids due to the more rapid metabolism of the former into VLC sphingomyelin and VLC hexosylceramide. In contrast, d16:1 and d18:1 ceramides show similar rates of turnover, indicating that the length of the sphingoid LCB does not influence the flux of ceramides through the biosynthetic pathway. Together, these data demonstrate that the N-acyl chain length of SLs may not only affect membrane biophysical properties but also influence the rate of metabolism of SLs so as to regulate their levels and perhaps their biological functions.
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Affiliation(s)
- Iris D Zelnik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Giora Volpert
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Leena E Viiri
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere Finland
| | | | - Tamar Arazi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Katriina Aalto-Setälä
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere Finland
| | - Reijo Laaksonen
- Zora Biosciences Oy, Espoo, Finland
- Finnish Cardiovascular Research Center Tampere, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Reidy PT, Mahmassani ZS, McKenzie AI, Petrocelli JJ, Summers SA, Drummond MJ. Influence of Exercise Training on Skeletal Muscle Insulin Resistance in Aging: Spotlight on Muscle Ceramides. Int J Mol Sci 2020; 21:ijms21041514. [PMID: 32098447 PMCID: PMC7073171 DOI: 10.3390/ijms21041514] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
Intramuscular lipid accumulation has been associated with insulin resistance (IR), aging, diabetes, dyslipidemia, and obesity. A substantial body of evidence has implicated ceramides, a sphingolipid intermediate, as potent antagonists of insulin action that drive insulin resistance. Indeed, genetic mouse studies that lower ceramides are potently insulin sensitizing. Surprisingly less is known about how physical activity (skeletal muscle contraction) regulates ceramides, especially in light that muscle contraction regulates insulin sensitivity. The purpose of this review is to critically evaluate studies (rodent and human) concerning the relationship between skeletal muscle ceramides and IR in response to increased physical activity. Our review of the literature indicates that chronic exercise reduces ceramide levels in individuals with obesity, diabetes, or hyperlipidemia. However, metabolically healthy individuals engaged in increased physical activity can improve insulin sensitivity independent of changes in skeletal muscle ceramide content. Herein we discuss these studies and provide context regarding the technical limitations (e.g., difficulty assessing the myriad ceramide species, the challenge of obtaining information on subcellular compartmentalization, and the paucity of flux measurements) and a lack of mechanistic studies that prevent a more sophisticated assessment of the ceramide pathway during increased contractile activity that lead to divergences in skeletal muscle insulin sensitivity.
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Affiliation(s)
- Paul T. Reidy
- Department of Kinesiology and Health, Miami University, 420 S Oak St, Oxford, OH 45056, USA;
| | - Ziad S. Mahmassani
- Departments of Physical Therapy and Athletic Training, University of Utah, 520 Wakara Way, Salt Lake City, UT 84018, USA; (Z.S.M.); (A.I.M.); (J.J.P.)
| | - Alec I. McKenzie
- Departments of Physical Therapy and Athletic Training, University of Utah, 520 Wakara Way, Salt Lake City, UT 84018, USA; (Z.S.M.); (A.I.M.); (J.J.P.)
| | - Jonathan J. Petrocelli
- Departments of Physical Therapy and Athletic Training, University of Utah, 520 Wakara Way, Salt Lake City, UT 84018, USA; (Z.S.M.); (A.I.M.); (J.J.P.)
| | - Scott A. Summers
- Department of Nutrition and Integrative Physiology, University of Utah, 250 1850 E, Salt Lake City, UT 84112, USA;
| | - Micah J. Drummond
- Departments of Physical Therapy and Athletic Training, University of Utah, 520 Wakara Way, Salt Lake City, UT 84018, USA; (Z.S.M.); (A.I.M.); (J.J.P.)
- Correspondence:
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7
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Daurio NA, Wang Y, Chen Y, Zhou H, Carballo-Jane E, Mane J, Rodriguez CG, Zafian P, Houghton A, Addona G, McLaren DG, Zhang R, Shyong BJ, Bateman K, Downes DP, Webb M, Kelley DE, Previs SF. Spatial and temporal studies of metabolic activity: contrasting biochemical kinetics in tissues and pathways during fasted and fed states. Am J Physiol Endocrinol Metab 2019; 316:E1105-E1117. [PMID: 30912961 DOI: 10.1152/ajpendo.00459.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The regulation of nutrient homeostasis, i.e., the ability to transition between fasted and fed states, is fundamental in maintaining health. Since food is typically consumed over limited (anabolic) periods, dietary components must be processed and stored to counterbalance the catabolic stress that occurs between meals. Herein, we contrast tissue- and pathway-specific metabolic activity in fasted and fed states. We demonstrate that knowledge of biochemical kinetics that is obtained from opposite ends of the energetic spectrum can allow mechanism-based differentiation of healthy and disease phenotypes. Rat models of type 1 and type 2 diabetes serve as case studies for probing spatial and temporal patterns of metabolic activity via [2H]water labeling. Experimental designs that capture integrative whole body metabolism, including meal-induced substrate partitioning, can support an array of research surrounding metabolic disease; the relative simplicity of the approach that is discussed here should enable routine applications in preclinical models.
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Affiliation(s)
- Natalie A Daurio
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Yichen Wang
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Ying Chen
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Haihong Zhou
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Ester Carballo-Jane
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Joel Mane
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Carlos G Rodriguez
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Peter Zafian
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Andrea Houghton
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - George Addona
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - David G McLaren
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Rena Zhang
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Bao Jen Shyong
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Kevin Bateman
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Daniel P Downes
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Maria Webb
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - David E Kelley
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Stephen F Previs
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
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