TY - JOUR
T1 - Transfer of glucose hydrogens via acetyl-CoA, malonyl-CoA, and NADPH to fatty acids during de novo lipogenesis
AU - Belew, Getachew Debas
AU - Silva, Joao
AU - Rito, Joao
AU - Tavares, Ludgero
AU - Viegas, Ivan
AU - Teixeira, Jose
AU - Oliveira, Paulo J.
AU - Macedo, Maria Paula
AU - Jones, John G.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Deuterated water (2H2O) is widely used for measuring de novo lipogenesis (DNL). 2H is incorporated into fatty acids via exchange between body water and the hydrogens of acetyl-CoA, malonyl-CoA, and NADPH. Previous studies concluded that these exchanges are incomplete; therefore, fatty acid 2H enrichment requires correcting. In mice, we measured the 2H enrichment of fatty acid positions 2 and 3 and methyl hydrogens from [U-2H7]glucose to determine 2H transfer from glucose to fatty acid via malonyl-CoA, NADPH, and acetyl-CoA, respectively. Positional fatty acid 2H enrichments were compared with 13C enrichment of the same sites from an equivalent amount of [U-13C6]glucose provided alongside the [U-2H7]glucose tracer. Transfer of glucose 2H to fatty acid position 2 and methyl sites was low (2H enrichment of 0.06 ± 0.01 and 0.14 ± 0.01 relative to 13C) indicating extensive exchange at both malonyl- and acetyl-CoA, respectively. Transfer of glucose 2H into fatty acid position 3 was more extensive (0.46 ± 0.04 relative to 13C, P < 10-5 vs. position 2), indicating a more limited exchange of those glucose hydrogens that were transferred via NADPH. However, mice provided with [U-13C6]glucose and 2H2O had equivalent 2H enrichments of fatty acid positions 2 and 3, suggesting that in this setting, NADPH and body water 2H had exchanged extensively. This is explained by contributions of substrates other than exogenous glucose to DNL coupled with their extensive 2H enrichment from 2H2O prior to DNL. Under such conditions, 2H enrichment of fatty acids from 2H2O does not need correction.
AB - Deuterated water (2H2O) is widely used for measuring de novo lipogenesis (DNL). 2H is incorporated into fatty acids via exchange between body water and the hydrogens of acetyl-CoA, malonyl-CoA, and NADPH. Previous studies concluded that these exchanges are incomplete; therefore, fatty acid 2H enrichment requires correcting. In mice, we measured the 2H enrichment of fatty acid positions 2 and 3 and methyl hydrogens from [U-2H7]glucose to determine 2H transfer from glucose to fatty acid via malonyl-CoA, NADPH, and acetyl-CoA, respectively. Positional fatty acid 2H enrichments were compared with 13C enrichment of the same sites from an equivalent amount of [U-13C6]glucose provided alongside the [U-2H7]glucose tracer. Transfer of glucose 2H to fatty acid position 2 and methyl sites was low (2H enrichment of 0.06 ± 0.01 and 0.14 ± 0.01 relative to 13C) indicating extensive exchange at both malonyl- and acetyl-CoA, respectively. Transfer of glucose 2H into fatty acid position 3 was more extensive (0.46 ± 0.04 relative to 13C, P < 10-5 vs. position 2), indicating a more limited exchange of those glucose hydrogens that were transferred via NADPH. However, mice provided with [U-13C6]glucose and 2H2O had equivalent 2H enrichments of fatty acid positions 2 and 3, suggesting that in this setting, NADPH and body water 2H had exchanged extensively. This is explained by contributions of substrates other than exogenous glucose to DNL coupled with their extensive 2H enrichment from 2H2O prior to DNL. Under such conditions, 2H enrichment of fatty acids from 2H2O does not need correction.
KW - acetyl-coenzyme A
KW - deuterium nuclear magnetic resonance
KW - malonyl-coenzyme A
KW - pentose phosphate pathway
KW - reduced nicotinamide adenine dinucleotide phosphate
UR - http://www.scopus.com/inward/record.url?scp=85076065502&partnerID=8YFLogxK
U2 - 10.1194/jlr.RA119000354
DO - 10.1194/jlr.RA119000354
M3 - Article
C2 - 31575642
SN - 0022-2275
VL - 60
SP - 2050
EP - 2056
JO - Journal of Lipid Research
JF - Journal of Lipid Research
IS - 12
ER -