Transcriptional regulation of apolipoprotein A‐I expression in Hep G2 cells by phorbol ester

Vandenbrouck, Yves; Lambert, Gilles; Janvier, Brigitte; Girlich, Delphine; Béréziat, G.; Mangeney-Andreani, Marise

doi:10.1016/0014-5793(95)01252-x

Cited by 6 publications

(3 citation statements)

References 34 publications

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“…Vigilin, a protein implicated in both biosynthesis and metabolism of lipids and steroids, facilitates removal of excess cholesterol from cells [73] and secondly apolipoprotein A IV which facilitates transport of cholesterol to the liver were both expressed at higher level in fish fed PP compared to MP. The high expression of apolipoproteins in fish fed diets containing high levels of plant proteins has previously been observed [9,74] and is most likely indicates reduced cellular cholesterol in fish fed the PP diet due to decreased dietary cholesterol, associated with low fishmeal content, and/or in response to trace levels of phytoestrogens [75] and phorbol esters [76] co purified with the plant proteins.…”

Section: Discussionmentioning

confidence: 99%

Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

et al. 2012

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BackgroundAquaculture of piscivorous fish is in continual expansion resulting in a global requirement to reduce the dependence on wild caught fish for generation of fishmeal and fish oil. Plant proteins represent a suitable protein alternative to fish meal and are increasingly being used in fish feed. In this study, we examined the transcriptional response of Atlantic salmon (Salmo salar) to a high marine protein (MP) or low fishmeal, higher plant protein replacement diet (PP), formulated to the same nutritional specification within previously determined acceptable maximum levels of individual plant feed materials.ResultsAfter 77 days of feeding the fish in both groups doubled in weight, however neither growth performance, feed efficiency, condition factor nor organ indices were significantly different. Assessment of histopathological changes in the heart, intestine or liver did not reveal any negative effects of the PP diet. Transcriptomic analysis was performed in mid intestine, liver and skeletal muscle, using an Atlantic salmon oligonucleotide microarray (Salar_2, Agilent 4x44K). The dietary comparison revealed large alteration in gene expression in all the tissues studied between fish on the two diets. Gene ontology analysis showed, in the mid intestine of fish fed PP, higher expression of genes involved in enteritis, protein and energy metabolism, mitochondrial activity/kinases and transport, and a lower expression of genes involved in cell proliferation and apoptosis compared to fish fed MP. The liver of fish fed PP showed a lower expression of immune response genes but a higher expression of cell proliferation and apoptosis processes that may lead to cell reorganization in this tissue. The skeletal muscle of fish fed PP vs MP was characterized by a suppression of processes including immune response, energy and protein metabolism, cell proliferation and apoptosis which may reflect a more energy efficient tissue.ConclusionsThe PP diet resulted in significant effects on transcription in all the 3 tissues studied. Despite of these alterations, we demonstrated that high level of plant derived proteins in a salmon diet allowed fish to grow with equal efficiency as those on a high marine protein diet, and with no difference in biometric quality parameters.

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Section: Discussionmentioning

confidence: 99%

Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

et al. 2012

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“…Furthermore, TPA inhibits both SP-A (24,27,29) and SP-C gene expression acting at the level of transcription. 3 In hepatic cells, expression of T4 binding globulin, apolipoprotein A-1, and CYP7A genes are inhibited by TPA and responsiveness mapped to promoter regions containing HNF binding sites (17,55,56). The possible role of altered intracellular distribution of transcription factors in the regulation of these and potentially other genes awaits further investigation.…”

Section: Discussionmentioning

confidence: 99%

Phorbol Ester Down-regulation of Lung Surfactant Protein B Gene Expression by Cytoplasmic Trapping of Thyroid Transcription Factor-1 and Hepatocyte Nuclear Factor 3

Kumar¹,

Venkatesh²,

Planer³

et al. 1997

Journal of Biological Chemistry

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The lung-specific surfactant protein B (SP-B) is essential for surfactant function and normal respiration. We investigated the role of thyroid transcription factor-1 (TTF-1) and hepatocyte nuclear factor 3 (HNF3) in the down-regulation of SP-B gene expression by phorbol ester in pulmonary adenocarcinoma H441 cells. Responsiveness to 12-O-tetradecanoylphorbol-13-acetate (TPA) localized to the SP-B proximal promoter (؊140/؊65 bp) and specifically to binding sites for TTF-1 and HNF3, which act as cell-specific enhancers of SP-B expression. Treatment of cells with TPA (10 nM) caused a time-dependent decrease in both TTF-1 and HNF3 in nuclear extracts and accumulation of both factors in the cytoplasm as assessed by electromobility shift, Western, Southwestern, and immunofluorescence assays. Treatment did not alter the mRNA content or DNA binding activity for either transcription factor. We conclude that down-regulation of SP-B gene expression by phorbol ester involves cytoplasmic trapping and loss of TTF-1 and HNF3 from the nucleus. This mechanism of action is independent of AP-1 and other transcription factors known to be influenced by phorbol ester.

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“…Because plasma HDL levels are correlated with plasma apoAI and liver apoAI mRNA levels (2), it is thought that factors affecting apoAI gene expression play an important role in atherosclerosis susceptibility. Although a number of pharmacological, dietary, and physiological factors affect apoAI and HDL plasma levels (3)(4)(5)(6)(7)(8), the underlying molecular mechanisms remain obscure. For example, numer-ous observational studies and a recent randomized trial have shown that estrogen replacement therapy increases apoAI and HDL plasma levels (9 -11).…”

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confidence: 99%

Estrogen Regulation of the Apolipoprotein AI Gene Promoter through Transcription Cofactor Sharing

Harnish¹,

Evans²,

Scicchitano³

et al. 1998

Journal of Biological Chemistry

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Estrogen replacement therapy increases plasma concentrations of high density lipoprotein and its major protein constituent, apolipoprotein AI (apoAI). Studies with animal model systems, however, suggest opposite effects. In HepG2 cells stably expressing estrogen receptor alpha (ERalpha), 17beta-estradiol (E2) potently inhibited apoAI mRNA steady state levels. ApoAI promoter deletion mapping experiments indicated that ERalpha plus E2 inhibited apoAI activity through the liver-specific enhancer. Although the ERalpha DNA binding domain was essential but not sufficient for apoAI enhancer inhibition, ERalpha binding to the apoAI enhancer could not be detected by electrophoretic mobility shift assays. Western blotting and cotransfection assays showed that ERalpha plus E2 did not influence the abundance or the activity of the hepatocyte-enriched factors HNF-3beta and HNF-4, two transcription factors essential for apoAI enhancer function. Expression of the ERalpha coactivator RIP140 dramatically repressed apoAI enhancer function in cotransfection experiments, suggesting that RIP140 may also function as a coactivator on the apoAI enhancer. Moreover, estrogen regulation of apoAI enhancer activity was dependent upon the balance between ERalpha and RIP140 levels. At low ratios of RIP140 to ERalpha, E2 repressed apoAI enhancer activity, whereas at high ratios this repression was reversed. Regulation of the apoAI gene by estrogen may thus vary in direction and magnitude depending not only on the presence of ERalpha and E2 but also upon the intracellular balance of ERalpha and coactivators utilized by ERalpha and the apoAI enhancer.

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Transcriptional regulation of apolipoprotein A‐I expression in Hep G2 cells by phorbol ester

Cited by 6 publications

References 34 publications

Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

Phorbol Ester Down-regulation of Lung Surfactant Protein B Gene Expression by Cytoplasmic Trapping of Thyroid Transcription Factor-1 and Hepatocyte Nuclear Factor 3

Estrogen Regulation of the Apolipoprotein AI Gene Promoter through Transcription Cofactor Sharing

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