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Luo J, Zhu JJ, Sun YT, Shi HB, Li J. Inhibitions of FASN suppress triglyceride synthesis via the control of malonyl-CoA in goat mammary epithelial cells. ANIMAL PRODUCTION SCIENCE 2017. [DOI: 10.1071/an15708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fatty acid synthase (FASN) is the key enzyme for de novo fatty acid synthesis from acetyl-CoA and malonyl-CoA. All the steps involved in fatty acid synthesis by FASN have been clearly defined in monogastrics and ruminants. However, there are no data on the mechanism of how FASN affects triglyceride synthesis. Inhibition of FASN in goat mammary epithelial cells by C75, a synthetic inhibitor of FASN activity, and shRNA markedly suppressed the accumulation of triglyceride in goat mammary epithelial cells. Meanwhile, C75 treatment significantly reduced the relative content of monounsaturated fatty acids (C16:1 and C18:1). Corresponding to the suppression of lipid accumulation, both of C75 and shRNA also decreased the mRNA expression of GPAM, AGPAT6 and DGAT2, all of which are related to triglyceride synthesis. The fact that treatment of malonyl-CoA decreased the expression of these genes is consistent with the results of shRNA treatment. Furthermore, the supplement of malonyl-CoA enhanced the suppression on GPAM, AGPAT6, LPIN1, DGAT1 and DGAT2. The results underscore the role of malonyl-CoA in inhibition of FASN in regulating triglyceride synthesis in goat mammary epithelial cells.
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Li J, Luo J, Xu H, Wang M, Zhu J, Shi H, Haile AB, Wang H, Sun Y. Fatty acid synthase promoter: Characterization, and transcriptional regulation by sterol regulatory element binding protein-1 in goat mammary epithelial cells. Gene 2015; 561:157-64. [DOI: 10.1016/j.gene.2015.02.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/22/2015] [Accepted: 02/12/2015] [Indexed: 12/18/2022]
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Zhu JJ, Luo J, Sun YT, Shi HB, Li J, Wu M, Yu K, Haile AB, Loor JJ. Short communication: Effect of inhibition of fatty acid synthase on triglyceride accumulation and effect on lipid metabolism genes in goat mammary epithelial cells. J Dairy Sci 2015; 98:3485-91. [PMID: 25726120 DOI: 10.3168/jds.2014-8202] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 01/12/2015] [Indexed: 01/12/2023]
Abstract
The role of fatty acid synthase (FASN) on de novo fatty acid synthesis has been well established. In monogastrics, unlike acetyl-coenzyme A carboxylase, FASN is primarily controlled at the transcriptional level. However, no data exist on ruminant mammary cells evaluating effects of FASN knockdown on mRNA expression of lipogenic genes. Inhibition of FASN in mammary cells by C75-mediated interference, a synthetic inhibitor of FASN activity, and short hairpin RNA-mediated interference markedly reduced cellular triglyceride content at least in part by decreasing the expression of genes related to triglyceride synthesis (GPAT, AGPAT6, and DGAT2) and enhancing the expression of lipolysis-related genes (ATGL and HSL). Consistent with the markedly lower expression of genes related to lipid droplet formation and secretion (TIP47, ADFP, BTN1A1, and XDH), cellular lipid droplets also were reduced sharply after incubation with C75 or adenovirus-short-hairpin-RNA. The results underscored the essential role of FASN in the overall process of milk-fat formation in goat mammary epithelial cells.
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Affiliation(s)
- J J Zhu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - J Luo
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100.
| | - Y T Sun
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - H B Shi
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - J Li
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - M Wu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - K Yu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - A B Haile
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China 712100
| | - J J Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801
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Zhao WS, Hu SL, Yu K, Wang H, Wang W, Loor J, Luo J. Lipoprotein lipase, tissue expression and effects on genes related to fatty acid synthesis in goat mammary epithelial cells. Int J Mol Sci 2014; 15:22757-71. [PMID: 25501331 PMCID: PMC4284735 DOI: 10.3390/ijms151222757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/11/2014] [Accepted: 11/24/2014] [Indexed: 01/08/2023] Open
Abstract
Lipoprotein lipase (LPL) serves as a central factor in hydrolysis of triacylglycerol and uptake of free fatty acids from the plasma. However, there are limited data concerning the action of LPL on the regulation of milk fat synthesis in goat mammary gland. In this investigation, we describe the cloning and sequencing of the LPL gene from Xinong Saanen dairy goat mammary gland, along with a study of its phylogenetic relationships. Sequence analysis showed that goat LPL shares similarities with other species including sheep, bovine, human and mouse. LPL mRNA expression in various tissues determined by RT-qPCR revealed the highest expression in white adipose tissue, with lower expression in heart, lung, spleen, rumen, small intestine, mammary gland, and kidney. Expression was almost undetectable in liver and muscle. The expression profiles of LPL gene in mammary gland at early, peak, mid, late lactation, and the dry period were also measured. Compared with the dry period, LPL mRNA expression was markedly greater at early lactation. However, compared with early lactation, the expression was lower at peak lactation and mid lactation. Despite those differences, LPL mRNA expression was still greater at peak, mid, and late lactation compared with the dry period. Using goat mammary epithelial cells (GMEC), the in vitro knockdown of LPL via shRNA or with Orlistat resulted in a similar degree of down-regulation of LPL (respectively). Furthermore, knockdown of LPL was associated with reduced mRNA expression of SREBF1, FASN, LIPE and PPARG but greater expression of FFAR3. There was no effect on ACACA expression. Orlistat decreased expression of LIPE, FASN, ACACA, and PPARG, and increased FFAR3 and SREBF1 expression. The pattern of LPL expression was similar to the changes in milk fat percentage in lactating goats. Taken together, results suggest that LPL may play a crucial role in fatty acid synthesis.
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Affiliation(s)
- Wang-Sheng Zhao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Shi-Liang Hu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Kang Yu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Hui Wang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Wei Wang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Juan Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA.
| | - Jun Luo
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
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Mohammad MA, Haymond MW. Regulation of lipid synthesis genes and milk fat production in human mammary epithelial cells during secretory activation. Am J Physiol Endocrinol Metab 2013; 305:E700-16. [PMID: 23880316 PMCID: PMC3761196 DOI: 10.1152/ajpendo.00052.2013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Expression of genes for lipid biosynthetic enzymes during initiation of lactation in humans is unknown. Our goal was to study mRNA expression of lipid metabolic enzymes in human mammary epithelial cell (MEC) in conjunction with the measurement of milk fatty acid (FA) composition during secretory activation. Gene expression from mRNA isolated from milk fat globule (MFG) and milk FA composition were measured from 6 h to 42 days postpartum in seven normal women. Over the first 96 h postpartum, daily milk fat output increased severalfold and mirrored expression of genes for all aspects of lipid metabolism and milk FA production, including lipolysis at the MEC membrane, FA uptake from blood, intracellular FA transport, de novo FA synthesis, FA and glycerol activation, FA elongation, FA desaturation, triglyceride synthesis, cholesterol synthesis, and lipid droplet formation. Expression of the gene for a key lipid synthesis regulator, sterol regulatory element-binding transcription factor 1 (SREBF1), increased 2.0-fold by 36 h and remained elevated over the study duration. Expression of genes for estrogen receptor 1, thyroid hormone-responsive protein, and insulin-induced 2 increased progressively to plateau by 96 h. In contrast, mRNA of peroxisome proliferator-activated receptor-γ decreased severalfold. With onset of lactation, increased de novo synthesis of FA was the most prominent change in milk FA composition and mirrored the expression of FA synthesis genes. In conclusion, milk lipid synthesis and secretion in humans is a complex process requiring the orchestration of a wide variety of pathways of which SREBF1 may play a primary role.
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Affiliation(s)
- Mahmoud A Mohammad
- Department of Pediatrics, Children's Nutrition Research Center, U.S. Department of Agriculture/Agricultural Research Service, Baylor College of Medicine, Houston, Texas
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Identification of genes that regulate multiple cellular processes/responses in the context of lipotoxicity to hepatoma cells. BMC Genomics 2007; 8:364. [PMID: 17925029 PMCID: PMC2110894 DOI: 10.1186/1471-2164-8-364] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 10/09/2007] [Indexed: 01/20/2023] Open
Abstract
Background In order to devise efficient treatments for complex, multi-factorial diseases, it is important to identify the genes which regulate multiple cellular processes. Exposure to elevated levels of free fatty acids (FFAs) and tumor necrosis factor alpha (TNF-α) alters multiple cellular processes, causing lipotoxicity. Intracellular lipid accumulation has been shown to reduce the lipotoxicity of saturated FFA. We hypothesized that the genes which simultaneously regulate lipid accumulation as well as cytotoxicity may provide better targets to counter lipotoxicity of saturated FFA. Results As a model system to test this hypothesis, human hepatoblastoma cells (HepG2) were exposed to elevated physiological levels of FFAs and TNF-α. Triglyceride (TG) accumulation, toxicity and the genomic responses to the treatments were measured. Here, we present a framework to identify such genes in the context of lipotoxicity. The aim of the current study is to identify the genes that could be altered to treat or ameliorate the cellular responses affected by a complex disease rather than to identify the causal genes. Genes that regulate the TG accumulation, cytotoxicity or both were identified by a modified genetic algorithm partial least squares (GA/PLS) analysis. The analyses identified NADH dehydrogenase and mitogen activated protein kinases (MAPKs) as important regulators of both cytotoxicity and lipid accumulation in response to FFA and TNF-α exposure. In agreement with the predictions, inhibiting NADH dehydrogenase and c-Jun N-terminal kinase (JNK) reduced cytotoxicity significantly and increased intracellular TG accumulation. Inhibiting another MAPK pathway, the extracellular signal regulated kinase (ERK), on the other hand, improved the cytotoxicity without changing TG accumulation. Much greater reduction in the toxicity was observed upon inhibiting the NADH dehydrogenase and MAPK (which were identified by the dual-response analysis), than for the stearoyl-CoA desaturase (SCD) activation (which was identified for the TG-alone analysis). Conclusion These results demonstrate the applicability of GA/PLS in identifying the genes that regulate multiple cellular responses of interest and that genes regulating multiple cellular responses may be better candidates for countering complex diseases.
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Glasser F, Doreau M, Ferlay A, Loor JJ, Chilliard Y. Milk fatty acids: Mammary synthesis could limit transfer from duodenum in cows. EUR J LIPID SCI TECH 2007. [DOI: 10.1002/ejlt.200700017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Faergeman NJ, Ballegaard T, Knudsen J, Black PN, DiRusso C. Possible roles of long-chain fatty Acyl-CoA esters in the fusion of biomembranes. Subcell Biochem 2000; 34:175-231. [PMID: 10808334 DOI: 10.1007/0-306-46824-7_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Affiliation(s)
- N J Faergeman
- Department of Biochemistry and Molecular Biology, Albany Medical College, New York 12208, USA
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Rosendal J, Ertbjerg P, Knudsen J. Characterization of ligand binding to acyl-CoA-binding protein. Biochem J 1993; 290 ( Pt 2):321-6. [PMID: 7680855 PMCID: PMC1132275 DOI: 10.1042/bj2900321] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ligand binding to recombinant bovine acyl-CoA-binding protein (rACBP) was examined using a Lipidex 1000 competition assay and an e.p.r. spectroscopy displacement assay. Of all putative ligands tested, rACBP exhibited a high binding affinity only for acyl-CoA esters. No alternative ligands could be found in rat liver fractions purified on an affinity of column on which ACBP was coupled to Sepharose 4B. E.p.r. data indicate that both the acyl chain and the CoA head group of acyl-CoA are involved in binding and that the 3'-phosphate group on the ribose moiety of acyl-CoA esters plays a crucial role in the binding of acyl-CoA to ACBP. E.p.r. competition binding studies show that the binding affinity of acyl-CoA esters for rACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-CoA esters with 14-22 carbon atoms in the acyl chain. No correlation between the number of double bonds in the acyl chain and the binding affinity was observed. The experimental results strongly indicate that ACBP specifically binds long-chain acyl-CoA esters with a very high affinity, results that indicate that ACBP is likely to be involved in the intracellular transport and pool formation of these compounds.
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Affiliation(s)
- J Rosendal
- Institute of Biochemistry, Odense University, Denmark
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11
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Knudsen J. Acyl-CoA-binding and transport, an alternative function for diazepam binding inhibitor (DBI), which is identical with acyl-CoA-binding protein. Neuropharmacology 1991; 30:1405-10. [PMID: 1780038 DOI: 10.1016/s0028-3908(11)80009-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Acyl-CoA binding protein (ACBP) was originally identified as an artifact in a preparation of fatty acid binding protein. The amino acid sequence of ACBP from bovine, rat and human liver is identical to the sequence of diazepam binding inhibitor (DBI) from these species. ACBP and DBI are therefore one and the same protein. The tertiary structure of ACBP in solution has been determined by 2D-NMR. ACBP consists of 4 alpha-helixes, covering the sequence from amino acid 2-11, 20-38, 51-62 and 72-85, respectively. The protein is folded so that it forms a boomerang type of structure with helix 1 and 2 arranged antiparallel in the one arm of the boomerang, helix 3 and the non-helical part between helix 2 and 3 form the second arm in the boomerang. Helix 4 is located in an angle behind helix 1 and 2. NMR measurements of chemical shifts, induced by acyl-CoA binding, indicate that the binding site is located in the bottom of the V formed between the two arms of the boomerang. This location of the binding site is confirmed with affinity labelling with radioactive photoreactive acyl-CoA esters. ACBP does not bind free CoA or free fatty and short chain acyl-CoA esters (C2-C8). The affinity increases with increasing length of the acyl chain from C10-C20 and drops again in acyl-CoA esters with 22 and 24 carbon in the acyl chain.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Knudsen
- Institute of Biochemistry, Odense University, Denmark
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12
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Knudsen J. Acyl-CoA-binding protein (ACBP) and its relation to fatty acid-binding protein (FABP): an overview. Mol Cell Biochem 1990; 98:217-23. [PMID: 2266962 DOI: 10.1007/bf00231387] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Acyl-CoA-binding protein is a 10 Kd protein which binds medium- and long-chain acyl-CoA esters with high affinity. The concentration in liver is 2-4 times the acyl-CoA concentration. ACBP has much greater affinity for acyl-CoA than FABP. FABP from bovine heart and liver is unable to compete with multilamellar liposomes, Lipidex and microsomal membrane in binding acyl-CoA esters, whereas ACBP effectively extracts acyl-CoA from all those sources. Previously published results on the effect of FABP on acyl-CoA metabolism need to be reevaluated due to possible contamination with ACBP. Recently it was discovered that ACBP is identical to a putative neurotransmitter diazepam binding inhibitor. The possibility therefore exists that ACBP has more than one function.
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Affiliation(s)
- J Knudsen
- Institute of Biochemistry, Odense University, Denmark
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13
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Mikkelsen J, Knudsen J. Acyl-CoA-binding protein from cow. Binding characteristics and cellular and tissue distribution. Biochem J 1987; 248:709-14. [PMID: 3435479 PMCID: PMC1148607 DOI: 10.1042/bj2480709] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using the tyrosine fluorescence quenching as a criterion for acyl-CoA binding, we have shown that acyl-CoA-binding protein (ACBP) binds acyl-CoA esters with a chain length greater than C8 with equal affinity. The binding studies indicated a binding stoichiometry of 1 mol of acyl-CoA/2 mol of ACBP. The protein was found in liver, adipose tissue, intestinal mucosa, kidney, heart, brain, muscles and mammary gland. The highest concentration was found in liver cytosol and the lowest in muscles and mammary gland. ACBP could not be shown to bind non-esterified fatty acids.
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Affiliation(s)
- J Mikkelsen
- Institute of Biochemistry, Odense University, Denmark
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Hansen HO, Knudsen J. Effect of exogenous long-chain fatty acids on individual fatty acid synthesis by dispersed ruminant mammary gland cells. J Dairy Sci 1987; 70:1350-4. [PMID: 3624591 DOI: 10.3168/jds.s0022-0302(87)80155-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We investigated the effect of exogenously added fatty acids on de novo synthesis of individual fatty acids and their incorporation into triacylglycerols by dispersed lactating ruminant mammary gland epithelial cells. Palmitate addition strongly stimulated synthesis and incorporation of butyrate and, to a smaller extent, palmitate synthesis and incorporation. Oleic acid strongly inhibited synthesis of all fatty acids except butyrate, whereas the effect of lauric acid was nearly neutral. Free fatty acid depletion of the mammary gland cells potentiated the effect of palmitate and made oleate less inhibitory.
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Hansen HO, Knudsen J. Effect of exogenous long-chain fatty acids on lipid biosynthesis in dispersed ruminant mammary gland epithelial cells: esterification of long-chain exogenous fatty acids. J Dairy Sci 1987; 70:1344-9. [PMID: 3624590 DOI: 10.3168/jds.s0022-0302(87)80154-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Dispersed epithelial cells from lactating bovine and goat mammary glands incorporated acetate into all fatty acids (C4 to C16) that were incorporated into mainly triacylglycerols. The cells secreted free fatty acids only into the incubation medium, and this secretion was dependent on the concentration of albumin and the type and amount of exogenous fatty acid added to the medium. Addition of palmitic acid to the incubation medium stimulated synthesis and incorporation of fatty acids synthesized de novo into triacylglycerols, whereas stearic and linoleic acid were inhibitory.
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Mogensen IB, Schulenberg H, Hansen HO, Spener F, Knudsen J. A novel acyl-CoA-binding protein from bovine liver. Effect on fatty acid synthesis. Biochem J 1987; 241:189-92. [PMID: 3566708 PMCID: PMC1147542 DOI: 10.1042/bj2410189] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Bovine liver was shown to contain a hitherto undescribed medium-chain acyl-CoA-binding protein. The protein co-purifies with fatty-acid-binding proteins, but was, unlike these proteins, unable to bind fatty acids. The protein induced synthesis of medium-chain acyl-CoA esters on incubation with goat mammary-gland fatty acid synthetase. The possible function of the protein is discussed.
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Hansen HO, Tornehave D, Knudsen J. Synthesis of milk specific fatty acids and proteins by dispersed goat mammary-gland epithelial cells. Biochem J 1986; 238:167-72. [PMID: 3800930 PMCID: PMC1147111 DOI: 10.1042/bj2380167] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The method now described for preparation of dispersed lactating goat mammary-gland cells gives a high yield of morphologically and functionally normal mammary cells. The cells synthesize specific goat milk fatty acids in the right proportions, and they respond to hormones by increased protein synthesis. The cells can be frozen and thawed without losing the above properties, which makes them an excellent tool for metabolic and hormonal studies.
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Kuksis A, Marai L, Myher JJ, Cerbulis J, Farrell HM. Comparative study of the molecular species of chloropropanediol diesters and triacylglycerols in milk fat. Lipids 1986; 21:183-90. [PMID: 3702611 DOI: 10.1007/bf02534819] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In an effort to establish the origin of the fatty acid esters of 3-chloropropanediol, which recently have been isolated in small amounts from goat milk, we compared the molecular species composition of the chlorohydrin diesters and of goat milk triacylglycerols. The chloropropanediol diesters were found to be composed of molecular species containing C10-C18 fatty acids and corresponded closely in carbon number to those calculated for the long chain sn-1,2-diacylglycerol moieties of goat milk triacylglycerols. The molecular species of goat milk total triacylglycerols contained C4-C18 fatty acids. It is suggested that triacylglycerols and chloropropanediol diesters are derived from the same pool of long chain fatty acids. A molecular distillate of bovine milk fat did not contain chloropropanediol diesters, while the available samples of human milk fat were shown to contain alkyldiacylglycerols as the major components of a neutral lipid fraction corresponding in polarity to the chloropropanediol diesters.
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19
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Hansen HO, Grunnet I, Knudsen J. Triacylglycerol synthesis in goat mammary gland. The effect of ATP, Mg2+ and glycerol 3-phosphate on the esterification of fatty acids synthesized de novo. Biochem J 1984; 220:513-9. [PMID: 6547605 PMCID: PMC1153654 DOI: 10.1042/bj2200513] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Goat mammary-gland microsomal fraction by itself induces synthesis of medium-chain-length fatty acids by goat mammary fatty acid synthetase and incorporates short- and medium-chain fatty acids into triacylglycerol. Addition of ATP in the absence or presence of Mg2+ totally inhibits triacylglycerol synthesis from short- and medium-chain fatty acids, and severely inhibits synthesis de novo of medium-chain fatty acids. The inhibition by ATP of fatty acid synthesis and triacylglycerol synthesis de novo can be relieved by glycerol 3-phosphate. The effect of ATP could not be mimicked by the non-hydrolysable ATP analogue, adenosine 5'-[beta,gamma-methylene]triphosphate and could not be shown to be caused by inhibition of the diacylglycerol acyltransferase by a phosphorylation reaction. Possible explanations for the mechanism of the inhibition by ATP are discussed, and a hypothetical model for its action is outlined.
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