scholarly journals Hepatocyte ELOVL Fatty Acid Elongase 6 Determines Ceramide Acyl‐Chain Length and Hepatic Insulin Sensitivity in Mice

Hepatology ◽  
2020 ◽  
Vol 71 (5) ◽  
pp. 1609-1625 ◽  
Author(s):  
Takashi Matsuzaka ◽  
Motoko Kuba ◽  
Saori Koyasu ◽  
Yuta Yamamoto ◽  
Kaori Motomura ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Insulin Sensitivity ◽  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acid Elongase ◽  
Hepatic Insulin Sensitivity ◽  
Acyl Chain Length

scholarly journals The mitogenic activities of phosphatidate are acyl-chain-length dependent and calcium independent in C3H/10T1/2 cells.

1991 ◽  
Vol 2 (1) ◽  
pp. 57-64 ◽  
Author(s):  
M J Krabak ◽  
S W Hui
Keyword(s):  
Fatty Acid ◽  
Dna Synthesis ◽  
Chain Length ◽  
Acyl Chain ◽  
Calcium Transient ◽  
Signaling Mechanism ◽  
Acyl Chain Length ◽  
Dose Dependent Fashion ◽  
Continuous Presence ◽  
A Chain

Phosphatidates (PA or phosphatidic acid) were shown to have mitogenic properties, including the stimulation of DNA synthesis and calcium mobilization in C3H/10T1/2 cells. Their continuous presence for a minimum of 7 h induced DNA synthesis with kinetics similar to that observed when 10% fetal bovine serum was used as a mitogen. PAs with long chain saturated fatty acid moieties were more mitogenic, in a dose-dependent fashion, than PAs with short saturated or unsaturated fatty acid moieties. When compared with lysostearoyl-PA (LSPA), distearoyl-PA (DSPA) was as potent with respect to the induction of DNA synthesis. Lysooleoyl-PA (LOPA) was slightly more potent than dioleoyl-PA (DOPA), but much weaker than DSPA and LSPA. Preincubation with dilauroyl-PA (DLPA) reduces the mitogenic effect of DSPA by 85%. The pattern of mitogenic inhibition suggests that a chain-length-independent, yet PA-specific, mechanism is involved. Both DSPA and DLPA are equally taken up by the cells after 30 min. LOPA, but not LSPA, produced a large calcium transient (1.3 microM), which we found to be derived from intracellular sources. DSPA, the most mitogenic PA tested, produced a weaker transient (0.6 microM). Interestingly, LSPA did not produce any detectable calcium transient. These results suggest that the chain-length-specific step in the signaling mechanism of PA occurs after the initial chain-length-independent partitioning and/or binding to the membrane and that the induction of DNA synthesis is not related to the observed calcium transients.

scholarly journals The elongation of exogenous fatty acids and the control of phospholipid acyl chain length in Micrococcus cryophilus

1980 ◽  
Vol 188 (3) ◽  
pp. 585-592 ◽  
Author(s):  
S P Sandercock ◽  
N J Russell
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Chain Length ◽  
De Novo ◽  
Acyl Chain ◽  
Psychrophilic Bacterium ◽  
Fatty Acid Elongation ◽  
Acyl Chain Length ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

The synthesis of fatty acids de novo from acetate and the elongation of exogenous satuated fatty acids (C12-C18) by the psychrophilic bacterium Micrococcus cryophilus (A.T.C.C. 15174) grown at 1 or 20 degrees C was investigated. M. cryophilus normally contains only C16 and C18 acyl chains in its phospholipids, and the C18/C16 ratio is altered by changes in growth temperature. The bacterium was shown to regulate strictly its phospholipid acyl chain length and to be capable of directly elongating myristate and palmitate, and possibly laurate, to a mixture of C16 and C18 acyl chains. Retroconversion of stearate into palmitate also occurred. Fatty acid elongation could be distinguished from fatty acid synthesis de novo by the greater sensitivity of fatty acid elongation to inhibition by NaAsO2 under conditions when the supply of ATP and reduced nicotinamide nucleotides was not limiting. It is suggested that phospholipid acyl chain length may be controlled by a membrane-bound elongase enzyme, which interconverts C16 and C18 fatty acids via a C14 intermediate; the activity of the enzyme could be regulated by membrane lipid fluidity.

scholarly journals Hepatic fatty acid uptake is regulated by the sphingolipid acyl chain length

2014 ◽  
Vol 1841 (12) ◽  
pp. 1754-1766 ◽  
Author(s):  
Woo-Jae Park ◽  
Joo-Won Park ◽  
Alfred H. Merrill ◽  
Judith Storch ◽  
Yael Pewzner-Jung ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Hepatic Fatty Acid ◽  
Acyl Chain Length

scholarly journals Phosphoproteomic Analysis across the Yeast Life Cycle Reveals Control of Fatty Acyl Chain Length by Phosphorylation of the Fatty Acid Synthase Complex

Cell Reports ◽  
2020 ◽  
Vol 32 (6) ◽  
pp. 108024
Author(s):  
Fernando Martínez-Montañés ◽  
Albert Casanovas ◽  
Richard R. Sprenger ◽  
Magdalena Topolska ◽  
David L. Marshall ◽  
...  
Keyword(s):  
Life Cycle ◽  
Fatty Acid ◽  
Chain Length ◽  
Fatty Acid Synthase ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Acyl Chain Length

scholarly journals Label-free CARS microscopy reveals similar triacylglycerol acyl chain length and saturation in myocellular lipid droplets of athletes and individuals with type 2 diabetes

Diabetologia ◽  
2020 ◽  
Vol 63 (12) ◽  
pp. 2654-2664
Author(s):  
Sabine Daemen ◽  
Anne Gemmink ◽  
Alexandra Paul ◽  
Nils Billecke ◽  
Katrina Rieger ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Sensitivity ◽  
Chain Length ◽  
Acyl Chain ◽  
Subcellular Location ◽  
Label Free ◽  
Acyl Chain Length ◽  
Type 2 Diabetic

Abstract Aims/hypothesis Intramyocellular lipid (IMCL) content associates with development of insulin resistance, albeit not in insulin-sensitive endurance-trained athletes (trained). Qualitative and spatial differences in muscle lipid composition may underlie this so-called athlete’s paradox. Here we studied triacylglycerol (TAG) composition of individual myocellular lipid droplets (LDs) in trained individuals and individuals with type 2 diabetes mellitus. Methods Trained ($$ \dot{V}{\mathrm{O}}_{2\max } $$ V ̇ O 2 max 71.0 ± 1.6 ml O2 [kg lean body mass (LBM)]−1 min−1), normoglycaemic (fasting glucose 5.1 ± 0.1 mmol/l) individuals and untrained ($$ \dot{V}{\mathrm{O}}_{2\max } $$ V ̇ O 2 max 36.8 ± 1.5 ml O2 [kg LBM]−1 min−1) individuals with type 2 diabetes (fasting glucose 7.4 ± 0.5 mmol/l), with similar IMCL content (3.5 ± 0.7% vs 2.5 ± 0.3%, p = 0.241), but at opposite ends of the insulin sensitivity spectrum (glucose infusion rate 93.8 ± 6.6 vs 25.7 ± 5.3 μmol [kg LBM]−1 min−1 for trained individuals and those with type 2 diabetes, respectively) were included from our database in the present study. We applied in situ label-free broadband coherent anti-Stokes Raman scattering (CARS) microscopy to sections from skeletal muscle biopsies to measure TAG acyl chain length and saturation of myocellular LDs. This approach uniquely permits examination of individual LDs in their native environment, in a fibre-type-specific manner, taking into account LD size and subcellular location. Results Despite a significant difference in insulin sensitivity, we observed remarkably similar acyl chain length and saturation in trained and type 2 diabetic individuals (chain length: 18.12 ± 0.61 vs 18.36 ± 0.43 number of carbons; saturation: 0.37 ± 0.05 vs 0.38 ± 0.06 number of C=C bonds). Longer acyl chains or higher saturation (lower C=C number) could be detected in subpopulations of LDs, i.e. large LDs (chain length: 18.11 ± 0.48 vs 18.63 ± 0.57 carbon number) and subsarcolemmal LDs (saturation: 0.34 ± 0.02 vs 0.36 ± 0.04 C=C number), which are more abundant in individuals with type 2 diabetes. Conclusions/interpretation In contrast to reports of profound differences in the lipid composition of lipids extracted from skeletal muscle from trained and type 2 diabetic individuals, our in situ, LD-specific approach detected only modest differences in TAG composition in LD subpopulations, which were dependent on LD size and subcellular location. If, and to what extent, these modest differences can impact insulin sensitivity remains to be elucidated.

scholarly journals Acyl chain length, saturation, and hydrophobicity modulate the efficiency of dietary fatty acid absorption in adult humans

2013 ◽  
Vol 305 (9) ◽  
pp. G620-G627 ◽  
Author(s):  
Ryan L. McKimmie ◽  
Linda Easter ◽  
Richard B. Weinberg
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Chain Length ◽  
Acyl Chain ◽  
Absorption Efficiency ◽  
Dietary Fatty Acids ◽  
Standard Diet ◽  
Absorption Coefficients ◽  
Fatty Acid Binding ◽  
Acyl Chain Length

Intestinal fat absorption is known to be, overall, a highly efficient process, but much less is known about the efficiency with which individual dietary fatty acids (FA) are absorbed by the adult small intestine. We therefore measured the absorption efficiency of the major dietary FA using sucrose polybehenate (SPB) as a nonabsorbable marker and analyzed how it is modulated by acyl chain physicochemical properties and polymorphisms of proteins involved in chylomicron assembly. Dietary FA absorption efficiency was measured in 44 healthy subjects fed a standard diet containing 35% fat and 5% SPB. FA and behenic acid (BA) were measured in homogenized diets and stool samples by gas chromatography-mass spectroscopy, and coefficients of absorption for each FA were calculated as 1 − [(FA/BA)feces/(FA/BA)diet]. Absorption coefficients for saturated FA decreased with increasing chain length and hydrophobicity (mean ± SE) and ranged from 0.95 ± 0.02 for myristate (14:0), 0.80 ± 0.03 for stearate (18:0), to 0.26 ± 0.02 for arachidate (20:0). Absorption coefficients for unsaturated FA increased with increasing desaturation from 0.79 ± 0.03 for elaidic acid (18:1t), 0.96 ± 0.01 for linoleate (18:2), to near complete absorption for eicosapentaenoic (20:5) and docosahexaenoic (22:6) acids. Of several common genetic polymorphisms in key proteins involved in the chylomicron assembly pathway, only the intestinal fatty acid-binding protein-2 A54T allele (rs1799883) had any impact on FA absorption. We conclude that acyl chain length, saturation, and hydrophobicity are the major determinants of the efficiency with which dietary FA are absorbed by the adult small intestine.

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