scholarly journals Immunohistochemical staining reveals differential expression of ACSL3 and ACSL4 in hepatocellular carcinoma and hepatic gastrointestinal metastases

2020 ◽  
Vol 40 (4) ◽  
Author(s):  
Haarith Ndiaye ◽  
Jorlin Y. Liu ◽  
Andrew Hall ◽  
Shane Minogue ◽  
Marsha Y. Morgan ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Acyl Chain ◽  
Hepatic Metastases ◽  
Normal Liver ◽  
Subcellular Fractionation ◽  
Fatty Acyl ◽  
Liver Malignancies ◽  
Tissue Arrays ◽  
Chain Acyl ◽  
Long Chain

Abstract Long-chain fatty acyl CoA synthetases (ACSLs) activate fatty acids by CoA addition thus facilitating their intracellular metabolism. Dysregulated ACSL expression features in several cancers and can affect processes such as ferroptosis, fatty acid β-oxidation, prostaglandin biosynthesis, steroidogenesis and phospholipid acyl chain remodelling. Here we investigate long chain acyl-CoA synthetase 3 (ACSL3) and long chain acyl-CoA synthetase 4 (ACSL4) expression in liver malignancies. The expression and subcellular localisations of the ACSL3 and ACSL4 isoforms in hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA) and hepatic metastases were assessed by immunohistochemical analyses of multiple tumour tissue arrays and by subcellular fractionation of cultured HepG2 cells. The expression of both enzymes was increased in HCC compared with normal liver. Expression of ACSL3 was similar in HCC and hepatic metastases but lower in healthy tissue. Increased ACSL3 expression distinguished HCC from CCA with a sensitivity of 87.2% and a specificity of 75%. ACSL4 expression was significantly greater in HCC than in all other tumours and distinguished HCC from normal liver tissue with a sensitivity of 93.8% and specificity of 93.6%. Combined ACSL3 and ACSL4 staining scores distinguished HCC from hepatic metastases with 80.1% sensitivity and 77.1% specificity. These enzymes had partially overlapping intracellular distributions, ACSL4 localised to the plasma membrane and both isoforms associated with lipid droplets and the endoplasmic reticulum (ER). In conclusion, analysis of ACSL3 and ACSL4 expression can distinguish different classes of hepatic tumours.

scholarly journals Thioesterase superfamily member 2 (Them2)/acyl-CoA thioesterase 13 (Acot13): a homotetrameric hotdog fold thioesterase with selectivity for long-chain fatty acyl-CoAs

2009 ◽  
Vol 421 (2) ◽  
pp. 311-322 ◽  
Author(s):  
Jie Wei ◽  
Hye Won Kang ◽  
David E. Cohen
Keyword(s):  
Acyl Chain ◽  
Substrate Inhibition ◽  
Fatty Acyl ◽  
Mouse Heart ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Chain Acyl ◽  
Hotdog Fold ◽  
Long Chain ◽  
Myristoyl Coa

Them2 (thioesterase superfamily member 2) is a 140-amino-acid protein of unknown biological function that comprises a single hotdog fold thioesterase domain. On the basis of its putative association with mitochondria, accentuated expression in oxidative tissues and interaction with StarD2 (also known as phosphatidylcholine-transfer protein, PC-TP), a regulator of fatty acid metabolism, we explored whether Them2 functions as a physiologically relevant fatty acyl-CoA thioesterase. In solution, Them2 formed a stable homotetramer, which denatured in a single transition at 59.3 °C. Them2 exhibited thioesterase activity for medium- and long-chain acyl-CoAs, with Km values that decreased exponentially as a function of increasing acyl chain length. Steady-state kinetic parameters for Them2 were characteristic of long-chain mammalian acyl-CoA thioesterases, with minimal values of Km and maximal values of kcat/Km observed for myristoyl-CoA and palmitoyl-CoA. For these acyl-CoAs, substrate inhibition was observed when concentrations approached their critical micellar concentrations. The acyl-CoA thioesterase activity of Them2 was optimized at physiological temperature, ionic strength and pH. For both myristoyl-CoA and palmitoyl-CoA, the addition of StarD2 increased the kcat of Them2. Enzymatic activity was decreased by the addition of phosphatidic acid/phosphatidylcholine small unilamellar vesicles. Them2 expression, which was most pronounced in mouse heart, was associated with mitochondria and was induced by activation of PPARα (peroxisome-proliferator-activated receptor α). We conclude that, under biological conditions, Them2 probably functions as a homotetrameric long-chain acyl-CoA thioesterase. Accordingly, Them2 has been designated as the 13th member of the mammalian acyl-CoA thioesterase family, Acot13.

scholarly journals Effect of long-chain fatty acyl-CoA on mitochondrial and cytosolic ATP/ADP ratios in the intact liver cell

1984 ◽  
Vol 220 (2) ◽  
pp. 371-376 ◽  
Author(s):  
S Soboll ◽  
H J Seitz ◽  
H Sies ◽  
B Ziegler ◽  
R Scholz
Keyword(s):  
Liver Cell ◽  
Adenine Nucleotide ◽  
Intact Cell ◽  
Inhibitory Effect ◽  
Fatty Acyl ◽  
Fed State ◽  
Physiological Relevance ◽  
Chain Acyl ◽  
Long Chain

The effect of long-chain acyl-CoA on subcellular adenine nucleotide systems was studied in the intact liver cell. Long-chain acyl-CoA content was varied by varying the nutritional state (fed and starved states) or by addition of oleate. Starvation led to an increase in the mitochondrial and a decrease in the cytosolic ATP/ADP ratio in liver both in vivo and in the isolated perfused organ as compared with the fed state. The changes were reversed on re-feeding glucose in liver in vivo or on infusion of substrates (glucose, glycerol) in the perfused liver, respectively. Similar changes in mitochondrial and cytosolic ATP/ADP ratios occurred on addition of oleate, but, importantly, not with a short-chain fatty acid such as octanoate. It is concluded that long-chain acyl-CoA exerts an inhibitory effect on mitochondrial adenine nucleotide translocation in the intact cell, as was previously postulated in the literature from data obtained with isolated mitochondria. The physiological relevance with respect to pyruvate metabolism, i.e. regulation of pyruvate carboxylase and pyruvate dehydrogenase by the mitochondrial ATP/ADP ratio, is discussed.

scholarly journals Functional Analysis of Rice Long-Chain Acyl-CoA Synthetase 9 (OsLACS9) in the Chloroplast Envelope Membrane

2020 ◽  
Vol 21 (6) ◽  
pp. 2223
Author(s):  
Aya Kitajima-Koga ◽  
Marouane Baslam ◽  
Yuuki Hamada ◽  
Namiko Ito ◽  
Tomoko Taniuchi ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Fatty Acyl ◽  
Laser Scanning Microscopy ◽  
Chloroplast Envelope ◽  
Confocal Laser ◽  
Starch Degradation ◽  
Envelope Membrane ◽  
Chain Acyl ◽  
Chloroplast Envelope Membrane ◽  
Long Chain

The long-chain acyl-CoA synthetases (LACSs) are involved in lipid synthesis, fatty acid catabolism, and the transport of fatty acids between subcellular compartments. These enzymes catalyze the critical reaction of fatty acyl chains to fatty acyl-CoAs for the triacylglycerol biosynthesis used as carbon and energy reserves. In Arabidopsis, LACSs are encoded by a family of nine genes, with LACS9 being the only member located in the chloroplast envelope membrane. However, the comprehensive role of LACS9 and its contribution to plant metabolism have not been explored thoroughly. In this study, we report on the identification and characterization of LACS9 mutants in rice plants. Our results indicate that the loss-of-function mutations in OsLACS9 affect the architecture of internodes resulting in dwarf plants with large starch granules in the chloroplast, showing the suppression of starch degradation. Moreover, the plastid localization of α-amylase I-1 (AmyI-1)—a key enzyme involved in starch breakdown in plastids—was suppressed in the lacs9 mutant line. Immunological and confocal laser scanning microscopy analyses showed that OsLACS9-GFP is located in the chloroplast envelope in green tissue. Microscopic analysis showed that OsLACS9s interact with each other in the plastid envelope membrane. Furthermore, OsLACS9 is also one of the proteins transported to plastids without a transit peptide or involvement of the Toc/Tic complex system. To identify the plastid-targeting signal of OsLACS9, the transient expression and localization of a series of N-terminal truncated OsLACS9-green fluorescent protein (GFP) fusion proteins were examined. Truncation analyses identified the N-terminal 30 amino acid residues to be required for OsLACS9 plastid localization. Overall, the data in this study provide an advanced understanding of the function of OsLACS9 and its role in starch degradation and plant growth.

scholarly journals Activation of a peroxisome-proliferating catabolite of cholic acid to its CoA ester

1993 ◽  
Vol 296 (1) ◽  
pp. 265-270 ◽  
Author(s):  
T Nishimaki-Mogami ◽  
A Takahashi ◽  
Y Hayashi
Keyword(s):  
Cholic Acid ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Liver Microsomes ◽  
Subcellular Fractionation ◽  
Fatty Acyl ◽  
Peroxisome Proliferator ◽  
Rat Liver Microsomes ◽  
Triton X ◽  
Long Chain

We have shown that a microbial cholic acid catabolite (4R)-4-(2,3,4,6,6a beta,7,8,9,9a alpha,9b beta-decahydro-6a beta-methyl-3-oxo- 1H-cyclopenta[f]quinolin-7 beta-yl)valeric acid (DCQVA), is a potent peroxisome proliferator. In this paper a possible key stage in DCQVA metabolism, the activation of DCQVA to its CoA ester, has been investigated in rat liver microsomes and particulate fractions. The microsomal reaction was dependent on CoA, ATP, DCQVA (0.2-1 mM) and protein content. The reaction was decreased by storage at 4 degrees C, preincubation of microsomes at 37 degrees C for 5 min, or inclusion of Triton X-100 in the reaction mixture. Such treatments also enhanced generation of long-chain fatty acyl-CoAs, as determined by h.p.l.c. analysis. The same effect was caused by exposing the microsomes to phospholipase A2, suggesting that endogenous fatty acids may compete with DCQVA for esterification with CoA. Subcellular fractionation of rat liver demonstrated that the activity of DCQVA-CoA synthesis was localized predominantly in the microsomal fraction, in contrast to long-chain fatty acyl-CoA synthetase, which was distributed among all particulate fractions. Administration of clofibrate of rats did not affect the distribution of DCQVA-CoA synthesis activity. In contrast to a 2-fold induction of long-chain fatty acyl-CoA synthetase by clofibrate treatment, the activity of DCQVA-CoA synthesis in the microsomal fraction decreased by 80%. These results suggest that DCQVA is activated by an enzyme distinct from long-chain fatty acyl-CoA synthetase. The resulting perturbation of fatty acid metabolism may be involved in the mechanism whereby DCQVA causes peroxisome proliferation.

Distinct transcriptional regulation of long-chain acyl-CoA synthetase isoforms and cytosolic thioesterase 1 in the rodent heart by fatty acids and insulin

2006 ◽  
Vol 290 (6) ◽  
pp. H2480-H2497 ◽  
Author(s):  
David J. Durgan ◽  
Justin K. Smith ◽  
Margaret A. Hotze ◽  
Oluwaseun Egbejimi ◽  
Karalyn D. Cuthbert ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acyl ◽  
Null Mouse ◽  
Peroxisome Proliferator ◽  
Futile Cycle ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rat Cardiomyocytes ◽  
Adult Rat ◽  
Chain Acyl ◽  
Long Chain

The molecular mechanism(s) responsible for channeling long-chain fatty acids (LCFAs) into oxidative versus nonoxidative pathways is (are) poorly understood in the heart. Intracellular LCFAs are converted to long-chain fatty acyl-CoAs (LCFA-CoAs) by a family of long-chain acyl-CoA synthetases (ACSLs). Cytosolic thioesterase 1 (CTE1) hydrolyzes cytosolic LCFA-CoAs to LCFAs, generating a potential futile cycle at the expense of ATP utilization. We hypothesized that ACSL isoforms and CTE1 are differentially regulated in the heart during physiological and pathophysiological conditions. Using quantitative RT-PCR, we report that the five known acsl isoforms ( acsl1, acsl3, acsl4, acsl5, and acsl6) and cte1 are expressed in whole rat and mouse hearts, as well as adult rat cardiomyocytes (ARCs). Streptozotocin-induced insulin-dependent diabetes (4 wk) and fasting (≤24 h) both dramatically induced cte1 and repressed acsl6 mRNA, with no significant effects on the other acsl isoforms. In contrast, high-fat feeding (4 wk) induced cte1 without affecting expression of the acsl isoforms in the heart. Investigation into the mechanism(s) responsible for these transcriptional changes uncovered roles for peroxisome proliferator-activated receptor-α (PPARα) and insulin as regulators of specific acsl isoforms and cte1 in the heart. Culturing ARCs with oleate (0.1–0.4 mM) or the PPARα agonists WY-14643 (1 μM) and fenofibrate (10 μM) consistently induced acsl1 and cte1. Conversely, PPARα null mouse hearts exhibited decreased acsl1 and cte1 expression. Culturing ARCs with insulin (10 nM) induced acsl6, whereas specific loss of insulin signaling within the heart (cardiac-specific insulin receptor knockout mice) caused decreased acsl6 expression. Our data expose differential regulation of acsl isoforms and cte1 in the heart, where acsl1 and cte1 are PPARα-regulated genes, whereas acsl6 is an insulin-regulated gene.

scholarly journals Higher-plant medium- and short-chain acyl-CoA oxidases: identification, purification and characterization of two novel enzymes of eukaryotic peroxisomal β-oxidation

1996 ◽  
Vol 320 (2) ◽  
pp. 607-614 ◽  
Author(s):  
Mark A. HOOKS ◽  
Kornelia BODE ◽  
Ivan COUÉE
Keyword(s):  
Molecular Mass ◽  
Subcellular Location ◽  
Maximal Activity ◽  
Fatty Acyl ◽  
Short Chain ◽  
Higher Plant ◽  
Medium Chain ◽  
Chain Acyl ◽  
Acyl Coa Oxidase ◽  
Long Chain

Medium- and short-chain acyl-CoA oxidases were identified in and subsequently purified from dark-grown maize plantlets. The oxidase showing preference for medium-chain fatty acyl-CoAs (C10–C14) was purified to homogeneity. The oxidase showing preference for short-chain fatty acyl-CoAs (C4–C8) was purified over 150-fold. Various catalytic properties confirmed these enzymes to be true acyl-CoA oxidases. They produced trans-2-enoyl-CoA and H2O2 from the saturated acyl-CoA, as verified by various independent assay techniques. They also exhibited FAD-dependent activity; i.e. removal of loosely bound FAD by gel filtration markedly reduced activity, which could be restored upon re-addition of FAD. They showed apparent Km values between 2 and 10 µM for the acyl-CoA substrate giving maximal activity, no activity with the corresponding free fatty acid, high pH optima (8.3–8.6) and a peroxisomal subcellular location. The medium-chain acyl-CoA oxidase was determined to be a monomeric protein with a molecular mass of 62 kDa. The short-chain acyl-CoA oxidase was shown to have a native molecular mass of 60 kDa, but exhibited a labile multimeric structure, as indicated by the elution of multiple peaks of activity during several chromatographic steps, and ultimately by the purification of a subunit of molecular mass 15 kDa. The medium- and short-chain acyl-CoA oxidases were demonstrated to be distinct from the maize equivalent of the cucumber glyoxysomal long-chain acyl-CoA oxidase previously purified and characterized [Kirsch, Loffler and Kindl (1986) J. Biol. Chem. 261, 8570–8575]. The maize long-chain acyl-CoA oxidase was partially purified to permit determination of its substrate specificity; it showed activity with a broad range of acyl-CoAs of chain length greater than C8, and maximal activity with C16. The implications of the existence of multiple acyl-CoA oxidases in the regulation of plant peroxisomal β-oxidation are discussed.

scholarly journals Transarterial Radioembolization (TARE) Agents beyond 90Y-Microspheres

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
C. Bouvry ◽  
X. Palard ◽  
J. Edeline ◽  
V. Ardisson ◽  
P. Loyer ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Treatment Options ◽  
Hepatic Metastases ◽  
Liver Malignancies ◽  
Liver Tumours ◽  
Alternative Technologies ◽  
Transarterial Radioembolization ◽  
Advanced Stages ◽  
New Treatment ◽  
90Y Microspheres

Liver malignancies, either primary tumours (mainly hepatocellular carcinoma and cholangiocarcinoma) or secondary hepatic metastases, are a major cause of death, with an increasing incidence. Among them, hepatocellular carcinoma (HCC) presents with a dark prognosis because of underlying liver diseases and an often late diagnosis. A curative surgical treatment can therefore only be proposed in 20 to 30% of the patients. However, new treatment options for intermediate to advanced stages, such as internal radionuclide therapy, seem particularly attractive. Transarterial radioembolization (TARE), which consists in the use of intra-arterial injection of a radiolabelled embolising agent, has led to very promising results. TARE with 90Y-loaded microspheres is now becoming an established procedure to treat liver tumours, with two commercially available products (namely, SIR-Sphere® and TheraSphere®). However, this technology remains expensive and is thus not available everywhere. The aim of this review is to describe TARE alternative technologies currently developed and investigated in clinical trials, with special emphasis on HCC.

scholarly journals Acyl-chain specificity of human milk bile-salt-activated lipase

1991 ◽  
Vol 279 (1) ◽  
pp. 297-302 ◽  
Author(s):  
C S Wang
Keyword(s):  
Human Milk ◽  
Bile Salt ◽  
Chain Length ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Acyl Chain Length ◽  
Enzyme Substrate ◽  
Consistent Trend ◽  
Kinetics Of ◽  
Long Chain

In order to probe the active-site structure of human milk bile-salt-activated lipase (BAL), the kinetics of the BAL-catalysed reaction were studied using monoesters as substrates. Among the fatty acyl chains, ranging from C8 to C16 of monoacylglycerols in a single equimolar assay mixture, there was a consistent trend of increased reactivity with decreased fatty-acyl-chain length for both the basal and taurocholate-stimulated activities of BAL. In addition, the detection of hydrolysis of long-chain monoacylglycerols in the absence of bile salt indicates that it is possible for the long-chain fatty acid monoester to form an enzyme-substrate complex with the basal form of BAL. I further examined the reaction kinetics of BAL with water-soluble short-chain esters of p-nitrophenol. The results indicated that there is a consistent trend towards a decreased Michaelis-Menten constant with increased acyl-chain length. Therefore it was concluded that the decreased reactivity with increased acyl-chain length of acylglycerols is probably not a consequence of the lowered affinity of the substrate for the enzyme. The fact that butyrate ester has the optimum acyl chain to be a substrate of BAL can be attributed to its acyl-chain length being long enough for interaction with the active centre of BAL and short enough to provide adequate positioning of the ester bond for transition state complex formation. The calculated free energy of BAL catalysis based on the derived kinetic parameters provides additional insight into the effect on the enzyme-substrate interaction of increasing the number of methylene groups in the acyl chain of substrates.

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