Triacylglycerol synthesis in goat mammary gland. The effect of ATP, Mg2+ and glycerol 3-phosphate on the esterification of fatty acids synthesized de novo.
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ABSTRACT:
SUBMITTER: Hansen HO
PROVIDER: S-EPMC1153654 | biostudies-other | 1984 Jun
REPOSITORIES: biostudies-other
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Project description:ATP alone had no effect on incorporation of fatty acids synthesized de novo and membrane-bound diacylglycerol into triacylglycerol. Combined addition of ATP and Mg2+ totally inhibits incorporation of fatty acids synthesized de novo and stimulated incorporation of membrane-bound diacylglycerol. ATP, Mg2+ and glycerol 3-phosphate stimulate incorporation of fatty acids synthesized de novo into triacylglycerol, but inhibited the incorporation of membrane-bound diacylglycerol. Diacylglycerol generated in situ was shown to be superior to diacylglycerols preloaded on the membrane as substrate for the diacylglycerol acyltransferase. A model is proposed to explain the effect of absorbed exogenous fatty acid on fatty acid synthesis de novo in goat mammary gland.
| S-EPMC1153655 | biostudies-other
Project description:Both subcellular fractions of lactating goat mammary gland and dispersed lactating goat mammary-gland cells were able to incorporate [U-3H]2-O-hexadecylglycerol into monoalkyl-monoacylglycerol. However, the incorporation of [U-3H]2-O-hexadecylglycerol into monoalkyl-monoacylglycerol by dispersed cells was not accompanied by incorporation of fatty acid synthesized de novo or added radiolabelled fatty acid. The result therefore shows that an active monoacylglycerol pathway does not exist in goat mammary gland.
| S-EPMC1147112 | biostudies-other
Project description:1. The presence of palmitoyl-CoA-l-glycerol 3-phosphate palmitoyltransferase (EC 2.3.1.15) has been demonstrated in a particulate fraction of mammary tissue from lactating guinea pigs. 2. Cell-free preparations also catalysed the activation of palmitate and oleate, and the conversion of enzymically formed phosphatidic acid into glycerides, in accord with the Kennedy pathway of glyceride formation. 3. The properties of the system that esterifies l-glycerol 3-phosphate were studied with respect to substrates and cofactors, and the reaction product was shown to be phosphatidic acid (1,2-diacyl glycerol 3-phosphate). 4. The extent to which newly formed phosphatidic acid was converted into glyceride in a cell-free system was dependent on the nature of the acyl donor, the concentration of subcellular particles, the time of incubation and the concentration of Mg(2+).
| S-EPMC1198292 | biostudies-other
Project description:Acyl-CoA:glycerol-3-phosphate acyltransferase (GPAT) catalyzes the first step during de novo synthesis of triacylglycerol. It has been well recognized that mammals possess multiple enzymatically distinct proteins with GPAT activity. Although the mitochondrial-associated GPAT has been cloned and extensively characterized, the molecular identity of the endoplasmic reticulum (ER)-associated GPAT, which accounts for the majority of total GPAT activity in most tissues, has remained elusive. Here we report the identification of genes encoding human and mouse ER-associated GPAT (termed GPAT3). GPAT3 is a member of the acyltransferase family predominantly expressed in tissues characterized by active lipid metabolism, such as adipose tissue, small intestine, kidney, and heart. Ectopic expression of GPAT3 leads to a significant increase in N-ethylmaleimide-sensitive GPAT activity, whereas acyltransferase activity toward a variety of other lysophospholipids, as well as neutral lipid substrates, is not altered. Overexpression of GPAT3 in mammalian cells results in increased triacylglycerol, but not phospholipid, formation. GPAT3 is localized to the ER when overexpressed in COS-7 cells. GPAT3 mRNA is dramatically up-regulated during adipocyte differentiation, is reciprocally regulated in adipose tissue and liver of ob/ob mice, and is up-regulated in mice treated with a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist. A substantial loss of GPAT activity in 3T3-L1 adipocytes was achieved by reducing GPAT3 mRNA levels through GPAT3-specific siRNA knockdown. These findings identify GPAT3 as a previously uncharacterized triacylglycerol biosynthetic enzyme. Similar to other lipogenic enzymes, GPAT3 may be useful as a target for the treatment of obesity.
| S-EPMC1702318 | biostudies-literature
Project description:Mesenchymal stem cells have been widely used in the treatment of various chronic diseases. The objective of this survey was to evaluate the therapeutic and regenerative potential of stem cells from adipose tissue (ASCs) in the milk production recovery repair of tissue injury in mastitis goats treated with antimicrobial agents prior to cell therapy. After the diagnosis of mastitis and treatment with gentamicin, eight lactating goats were selected for cellular and subsequent therapy, physical-chemical analysis of milk, ultrasonographic and histopathological examinations. The ASCs were taken from the subcutaneous fat of a young goat cultivated in vitro, marked with Qdots-655 and injected in the left mammary gland, being the right mammary gland used as the control. After 30 days the ultrasonographic and histopathological analyzes were repeated and, in the first lactation period, the physical-chemical analysis of the milk was reapeated. Before the cellular therapy, the physical-chemical quality of the milk was compromised and the ultrasonographic and histopathological analysis revealed a chronic inflammatory process and fibrous tissue. The marking of the ASCs with Qdots enabled the tracking, by fluorescence microscopy (BX41-OLYMPUS), in the mammary tissue. In the ASCs therapy, cultures showed high cellularity and characteristics favorable to preclinical studies; with the therapy the physical-chemical parameters of the milk, fat, protein, temperature and pH showed significant differences among the groups; five animals treated with ASCs reconstituted the functionality of the gland and the connective tissue reduced in quantity and inflammatory infiltrate cells. ASCs have potential for the possible regeneration of fibrous mastitis lesions in the mammary gland, however, it would be necessary to increase injection time for the histopathological analysis, since the reconstitution of the glandular acini within the assessed period was not finalized. ASCs can be used to reestablish milk production in goat with chronic mastitis repair mammary lesions, with potential to be a promising clinical alternative for animal rehabilitation for productivity.
| S-EPMC6804991 | biostudies-literature
Project description:During lactation, large amounts of calcium are exported from the mammary gland into milk to ensure skeletal growth of the offspring. Recent studies revealed that serotonin (5-HT) is essential to stimulate skeletal calcium resorption for milk synthesis. Our objective was to explore the correlation between circulating 5-HT and serum calcium and parathyroid hormone-related protein (PTHrP) concentrations around parturition in dairy goats. We also investigated the effect of 5-HT on PTHrP expression in cultured primary goat mammary epithelial cells (GMEC). Blood samples of multiparous Guanzhong dairy goats were collected on day -5 to 3 postpartum for analysis of serum concentrations of calcium, 5-HT, and PTHrP. Results revealed that from day -3 to 0 postpartum serum calcium and 5-HT concentrations decreased progressively, but serum PTHrP concentration only had a sharp drop in the postpartum period sampled. Correlation analysis of circulating 5-HT and serum calcium and PTHrP concentrations on day 1 and 2 postpartum revealed that low serum 5-HT concentration was positively correlated with serum total calcium or PTHrP concentration. By knocking down tryptophan hydroxylase-1 (TPH1) or adding 5-hydroxytryptophan (5-HTP) to decrease or increase the levels of 5-HT in GMEC, we observed that 5-HTP increased PTHrP expression in a dose-dependent manner and siTPH1 decreased PTHrP protein expression. Furthermore, 5-HT increased mRNA abundance of calcium-sensing receptor (CaSR) in a dose-dependent manner and decreased the expression of plasma membrane Ca2+ ATPase-1 (PMCA1). Taken together, 5-HT seems to induce PTHrP expression in goat mammary cells during and after parturition. These findings suggest that increasing 5-HT biosynthesis could be a potential therapeutic target for prevention of hypocalcemia in dairy goats.
| S-EPMC6093522 | biostudies-literature
Project description:BACKGROUND:Nutrition affects milk composition thus influencing its nutritional properties. Nutrition also modifies the expression of mammary genes, whose regulation is not fully understood. MicroRNAs (miRNA) are small non coding RNA which are important post-transcriptional regulators of gene expression by targeting messenger RNAs. Our goal was to characterize miRNA whose expression is regulated by nutrition in the lactating goat mammary gland, which may provide clues to deciphering regulations of the biosynthesis and secretion of milk components. METHODOLOGY/PRINCIPAL FINDINGS:Using high-throughput sequencing technology, miRNomes of the lactating mammary gland were established from lactating goats fed ad libitum or deprived of food for 48 h affecting milk production and composition. High throughput miRNA sequencing revealed 30 miRNA with an expression potentially modulated by food deprivation; 16 were down-regulated and 14 were up-regulated. Diana-microT predictive tools suggested a potential role for several nutriregulated miRNA in lipid metabolism. Among the putative targets, 19 were previously identified as differently expressed genes (DEG). The functions of these 19 DEG revealed, notably, their involvement in tissue remodelling. CONCLUSION/SIGNIFICANCE:In conclusion, this study offers the first evidence of nutriregulated miRNA in the ruminant mammary gland. Characterization of these 30 miRNA could contribute to a clearer understanding of gene regulation in the mammary gland in response to nutrition.
| S-EPMC4608672 | biostudies-literature
Project description:Development of mammary secretory epithelium and its functional differentiation occur during pregnancy under combined actions of ovarian steroids, pituitary hormones and growth factors. If the effect of these molecules is relatively well known, effect of differentiation factors expressed locally is not enough characterized. To understand local regulation of mammary tissue development and differentiation we realized transcriptional analysis on 5 physiological stages (4 during pregnancy and 1 during lactation). An appropriate experimental design was drawn to follow gene expression profiles during differentiation of mammary tissue. Results showed that at mid-pregnancy, mammary tissue was enough defferentiated into secretory epithelium to express milk protein genes and genes of the immune response system actors. But the secretoty activation of mammary epithelium was done only after parturition and wwas characterized by the expression of lipidogenesis genes. Keywords: time course, mammary gland differentiation, goat, pregnancy 18 samples, loop design
2010-05-16 | E-GEOD-14008 | biostudies-arrayexpress
Project description:CCAAT/enhancer binding protein α (C/EBPα) is the key transcription factor involved in lipid metabolism, however, the role of C/EBPα in milk fat synthesis of dairy goats remains unknown. The objective of the present research was to clarify the function of C/EBPα in goat mammary epithelial cells (GMECs) and its impact on peroxisome proliferator-activated receptor gamma (PPARG) promoter activity. In this study, C/EBPα overexpression increased its mRNA and protein levels by 42-fold and 6-fold, respectively. In contrast, transfecting siRNA targeting C/EBPα decreased its mRNA level to 20% and protein abundance to 80% of the basal level. The contents of lipid droplets, triacylglycerol (TAG), and cholesterol were increased (P < 0.05) in C/EBPα-overexpressing GMECs, and knockdown of C/EBPα led to the opposite results. Overexpression of C/EBPα significantly increased the expression levels of genes involved in TAG synthesis (AGPAT6, DGAT2, P < 0.01), lipid droplet formation (PLIN2, P < 0.01), and fatty acid synthesis (FADS2, P < 0.05; ELOVL6, P < 0.01). Knockdown of C/EBPα decreased (P < 0.05) the expression levels of AGPAT6, DGAT1, DGAT2, PLIN2, FADS2, and ELOVL6. C/EBPα upregulated the expression level of PPARG (P < 0.05), and four C/EBPα binding regions were identified in the PPARG promoter at -1,112 to -1,102 bp, -734 to -724 bp, -248 to -238 bp, and -119 to -109 bp. Knockdown of C/EBPα reduced (P < 0.05) the PPARG promoter activity when the C/EBPα binding regions were mutated at -1,112 to -1,102 bp, -734 to -724 bp, and -248 to -238 bp locations of the promoter. However, the promoter activity did not change when the mutation was located at -119 bp. In conclusion, our results suggest that C/EBPα can promote TAG synthesis in GMECs through its effects on mRNA abundance of genes related to lipid metabolism and regulation of the PPARG promoter activity via C/EBPα binding regions.
| S-EPMC9863032 | biostudies-literature
Project description:Development of mammary secretory epithelium and its functional differentiation occur during pregnancy under combined actions of ovarian steroids, pituitary hormones and growth factors. If the effect of these molecules is relatively well known, effect of differentiation factors expressed locally is not enough characterized. To understand local regulation of mammary tissue development and differentiation we realized transcriptional analysis on 5 physiological stages (4 during pregnancy and 1 during lactation). An appropriate experimental design was drawn to follow gene expression profiles during differentiation of mammary tissue. Results showed that at mid-pregnancy, mammary tissue was enough defferentiated into secretory epithelium to express milk protein genes and genes of the immune response system actors. But the secretoty activation of mammary epithelium was done only after parturition and wwas characterized by the expression of lipidogenesis genes. Keywords: time course, mammary gland differentiation, goat, pregnancy
2009-12-23 | GSE14008 | GEO