Intracellular Processes Associated with Vesicular Transport from Endoplasmic Reticulum to Golgi and Exocytosis: Ethanol-Induced Changes in Membrane Biogenesis

Slomiany, Amalia; Grabska, Maria; Piotrowski, Elzbieta; Sengupta, Shipra; Morita, Masanori; Kasinathan, Chinnaswamy; Slomiany, Bronislaw L.

doi:10.1006/abbi.1994.1164

Cited by 21 publications

(62 citation statements)

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“…As far as the uptake of choline is concerned, the level of radioactivity in the PC in ethanol-treated hepatocytes was markedly lower than in the controls. This lower PC synthesis is consistent with the decrease in PC levels found in our study and those of other authors who have also found a decrease in PC synthesis in the livers of chronically-treated rats [22,25]. In spite of the fall in PC synthetic activity after chronic ethanol feeding, when the cells were incubated in vitro in the presence of alcohol we observed a significant increase in the incorporation of choline into PC in both the ethanol-treated and control hepatocytes.…”

Section: Resultssupporting

confidence: 93%

“…This reduction is due to a decrease in free cholesterol levels because the quantity of esterified cholesterol is unchanged in hepatocytes isolated from alcoholic rats compared to those of the controls. As far as phospholipid levels are concerned, in accordance with what we [21] and others authors [22,23] have reported, chronic ethanol ingestion significantly decreases PC levels without altering the concentration of other phospholipids in the hepatocyte.…”

Section: Resultssupporting

confidence: 90%

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Chronic ingestion of ethanol stimulates lipogenic response in rat hepatocytes

2001

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We isolated hepatocytes from rats chronically fed with ethanol and pair-fed control rats and incubated them both in the presence and absence of 100 mM ethanol in order to analyze the uptake into their lipids of several radiolabeled exogenous substrates. The hepatocytes treated chronically with ethanol showed higher lipogenic activity both in neutral lipids and phospholipids from serine, ethanolamine, glycerol and oleate. The only exception found was in the incorporation of choline into phosphatidylcholine (PC), which was lower in the hepatocytes from ethanol-fed rats than in the controls and was concomitant with a decrease in the PC levels of the ethanol-fed hepatocytes. The results obtained after exposing the cells to 100 mM ethanol in vitro indicate that in general the hepatocytes from ethanol-fed rats exhibit a higher lipogenic activity than the control cells. The only difference in the response to ethanol in vitro was found in the biosynthesis of phosphatidylserine (PS) from serine, which rose significantly in control cells but was unaffected in alcoholic hepatocytes. We put this difference in response down to specific adaptation to ethanol feeding.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 90%

Chronic ingestion of ethanol stimulates lipogenic response in rat hepatocytes

2001

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“…The cell membranes and subcellular organelle fractions (mitochondria, ER, Golgi) were recovered from the cold or radiolabeled cells as described earlier [40]- [43] [46] [47] [54]- [58]. The ER and Golgi organelles sediment, remaining after separation of nuclei, mitochondria, endosomes and lysosomes, and cell cytosol, was suspended in the buffer containing 0.2 M PIPES (pH 6.9), 2.0 M glycerol, 1 mM EGTA and 1.0 mM magnesium acetate and applied on the top of discontinuous gradient of 2.0/1.5/1.3/1.0 M sucrose and centrifuged at 100,000 xg for 16 h. The cell membranes were recovered from 1.0 M sucrose, ER from 1.3 M and 1.5 M sucrose and Golgi from the top of the 2.0 M sucrose.…”

Section: Preparation Of Cellular Organelles and Membranesmentioning

confidence: 99%

Concluding Step in Cell Restitution Cycle: ER Transport Vesicles with Sphingolipids in the Outer Leaflet of the Membrane Restore Lysosomes

Slomiany¹,

Slomiany²

2014

ABC

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Restitution of the cell organelles and the membrane implicates serine palmitoyltransferase (SPT) in signal-specific and selective assembly of the transport vesicles. Here, we reveal that SPT, embedded in the outer leaflet (OL) of endoplasmic reticulum (ER), is engaged in the synthesis of ER transport vesicles that recondition cell organelles, and the inner leaflet (IL) SPT in the restitution of the cell membrane. The OL SPT impacts assembly of sphingomyelinase (SMase)-susceptible ER vesicles but not the SMase-resistant and sphingolipid (SPhL) core-carrying vesicles that refurbish the cell membrane. The investigation of the SPT-initiated differences in the placement of SPhL in vesicular membranes by utilizing ER depleted of OL SPT, allows us to conclude that the restitution of endosomal and lysosomal membranes is achieved with the involvement of OL SPT, whereas the IL SPT is involved in formation of the lipid core for glycosphingolipids (GSL) and sphingomyelin (SM) of the apical and basolateral cell membrane. These findings along with our previously published report (Slomiany and Slomiany, Advances in Biological Chemistry, 2013, 3, 275-287), provide a clear distinction between the processes that renovate cell membrane and its organelles from that of the endocytotic cell debridement, and show that vesicles are navigated to the specific organelles and the cell membrane by the biomembrane constituents programmed in ER.

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“…To our knowledge there are few reports on the effects of ethanol on the biosynthetic pathways of individual phospholipids in spite of their importance as components of biological membranes and their involvement in processes such as membrane fusion, membrane asymmetry or interactions with specific proteins. Slomiany et al (1994) have shown that in alcoholic rats, PC biosynthesis is reduced by 50% as compared to pair-fed controls. Also in our laboratory we have recently demonstrated that in rat hepatocytes, chronic alcohol treatment alters the incorporation of exogenous polar bases into PE and PC via CDP-derivatives and into PS via base-exchange reaction increasing PE and PS biosynthesis and decreasing synthesis of PC (Carrasco et al, 1996).…”

Section: Introductionmentioning

confidence: 98%

Evidence of differential effects produced by ethanol on specific phospholipid biosynthetic pathways in rat hepatocytes

Carrasco

Sanchez-Amate

Marco

et al. 1996

British J Pharmacology

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1 The aim of the present study was to investigate the effects of ethanol in vitro on the phospholipid biosynthetic pathways in hepatocytes isolated from the rat. We have used [methyl-"4C] products of the CDP-choline and CDP-ethanolamine pathways. Radioactivity in the metabolic intermediates of both pathways was significantly decreased and the amount of label in PE was reduced whilst that of PC was not modified. 3 In the presence of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase (ADH) activity, ethanol produces a reduction in the label of choline phosphate, ethanolamine phosphate and a significant decrease in the amount of PC and PE radiolabel. 4 On the other hand, ethanol increases the incorporation of serine into phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine, although this effect is observed only in the absence of 4-methylpyrazole, indicating that this alteration is produced by some metabolite generated as a consequence of hepatic alcohol metabolism. 5 Ethanol also interferes with the methylation of phosphatidylethanolamine produced via the CDPethanolamine pathway but it does not alter phosphatidylethanolamine methylation when this phospholipid is produced by mitochondrial phosphatidylserine decarboxylation, suggesting the existence of different intramembrane pools of phosphatidylethanolamine, which may exhibit different sensitivity to alcohol. 6 Our results indicate that ethanol exerts two different effects on phospholipid metabolism in hepatocytes: a stimulatory effect on the incorporation of exogenous substrates into different phospholipids probably related to an alteration in the availability of lipogenic substrates as a consequence of ethanol metabolism, and another inhibitory effect produced by ethanol per se, which can be observed only when ethanol metabolism is inhibited by the presence of a specific inhibitor of alcohol dehydrogenase activity.

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Intracellular Processes Associated with Vesicular Transport from Endoplasmic Reticulum to Golgi and Exocytosis: Ethanol-Induced Changes in Membrane Biogenesis

Cited by 21 publications

References 0 publications

Chronic ingestion of ethanol stimulates lipogenic response in rat hepatocytes

Chronic ingestion of ethanol stimulates lipogenic response in rat hepatocytes

Concluding Step in Cell Restitution Cycle: ER Transport Vesicles with Sphingolipids in the Outer Leaflet of the Membrane Restore Lysosomes

Evidence of differential effects produced by ethanol on specific phospholipid biosynthetic pathways in rat hepatocytes

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