Glycerophospholipids and cholesterol composition of bile in bile-fistula rats treated with monensin

Casu, A; Camogliano, L.

doi:10.1016/0005-2760(90)90117-g

Cited by 13 publications

(8 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, when the cells had been pretreated with monensin (10 M; Table I), only 17 Ϯ 3% of the BC was faintly labeled. Monensin is known to block vesicular transport from the Golgi apparatus to the PM and was shown to bring about a decrease in biliary lipid secretion (Casu and Camogliano, 1990). Since monensin treatment did not affect C 6 -NBD-Cer metabolism (data not shown), our data show that monensin treatment of HepG2 cells, in agreement with results reported previously (Lipsky and Pagano, 1985;Kok and Hoekstra, 1994), inhibits (vesicular) lipid transport exiting from the Golgi.…”

Section: Sorting Of C 6 -Nbd-glccer In a Sub-apical Compartment Does supporting

confidence: 92%

Segregation of Glucosylceramide and Sphingomyelin Occurs in the Apical to Basolateral Transcytotic Route in HepG2 Cells

IJzendoorn

Zegers

Kok

et al. 1997

The Journal of Cell Biology

105

View full text Add to dashboard Cite

HepG2 cells are highly differentiated hepatoma cells that have retained an apical, bile canalicular (BC) plasma membrane polarity. We investigated the dynamics of two BC-associated sphingolipids, glucosylceramide (GlcCer) and sphingomyelin (SM). For this, the cells were labeled with fluorescent acyl chainlabeled 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)- amino]hexanoic acid (C6-NBD) derivatives of either GlcCer (C6-NBD-GlcCer) or SM (C6-NBD-SM). The pool of the fluorescent lipid analogues present in the basolateral plasma membrane domain was subsequently depleted and the apically located C6-NBD-lipid was chased at 37°C. By using fluorescence microscopical analysis and a new assay that allows an accurate estimation of the fluorescent lipid pool in the apical membrane, qualitative and quantitative insight was obtained concerning kinetics, extent and (intra)cellular sites of the redistribution of apically located C6-NBD-GlcCer and C6-NBD-SM. It is demonstrated that both lipids display a preferential localization, C6-NBD-GlcCer in the apical and C6-NBD-SM in the basolateral area. Such a preference is expressed during transcytosis of both sphingolipids from the apical to the basolateral plasma membrane domain, a novel lipid trafficking route in HepG2 cells. Whereas the vast majority of the apically derived C6-NBD-SM was rapidly transcytosed to the basolateral surface, most of the apically internalized C6-NBD-GlcCer was efficiently redirected to the BC. The redirection of C6-NBD-GlcCer did not involve trafficking via the Golgi apparatus. Evidence is provided which suggests the involvement of vesicular compartments, located subjacent to the apical plasma membrane. Interestingly, the observed difference in preferential localization of C6-NBD-GlcCer and C6NBD-SM was perturbed by treatment of the cells with dibutyryl cAMP, a stable cAMP analogue. While the preferential apical localization of C6-NBD-GlcCer was amplified, dibutyryl cAMP-treatment caused apically retrieved C6-NBD-SM to be processed via a similar pathway as that of C6-NBD-GlcCer.The data unambiguously demonstrate that segregation of GlcCer and SM occurs in the reverse transcytotic route, i.e., during apical to basolateral transport, which results in the preferential localization of GlcCer and SM in the apical and basolateral region of the cells, respectively. A role for non-Golgi–related, sub-apical vesicular compartments in the sorting of GlcCer and SM is proposed.

show abstract

Section: Sorting Of C 6 -Nbd-glccer In a Sub-apical Compartment Does supporting

confidence: 92%

Segregation of Glucosylceramide and Sphingomyelin Occurs in the Apical to Basolateral Transcytotic Route in HepG2 Cells

IJzendoorn

Zegers

Kok

et al. 1997

The Journal of Cell Biology

105

View full text Add to dashboard Cite

show abstract

“…The role of the Golgi apparatus in the packing and sorting of intracellular lipids, including cholesterol, to the plasma membrane has been clearly characterized in peripheral cells [40][41][42]. It is noteworthy that ionophores, which interfere with the Golgi functions [43], decrease both the sinusoidal secretion of VLDL [44] and the canalicular secretion of cholesterol and phospholipids (present results and [18]). The ER plays a fundamental role in the regulation of intrahepatic cholesterol metabolism [6].…”

Section: Discussionmentioning

confidence: 58%

“…Colchicine is a well known microtubule-disrupting agent [45] and its effects on the vesicle-mediated transport of proteins and lipids have been extensively studied in cultured cells and in the whole animal [15][16][17]46]. Monensin is an ionophore that disrupts the trans-Golgi elements and inhibits the intracellular transport of membrane and secretory proteins, and some lipids [15,16,18,43]. Although both drugs inhibited total biliary cholesterol secretion, neither colchicine nor monensin did affect newly synthesized biliary cholesterol transfer in control rats.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Modulation of intrahepatic cholesterol trafficking: evidence by in vivo antisense treatment for the involvement of sterol carrier protein-2 in newly synthesized cholesterol transport into rat bile

PUGLIELLI¹,

RIGOTTI²,

AMIGO³

et al. 1998

Biochemical Journal

View full text Add to dashboard Cite

“…However, experiments with microtubule inhibitors have shown that biliary lipid secretion depends on vesicular transport [151][152][153], but neither the nature nor the intracellular transport route of these vesicles have been elucidated with certainty [150]. Also, an inhibitory effect of monensin on biliary lipid secretion has been reported [154], but this was not confirmed by others [155]. Some evidence points towards the Golgi apparatus as an assembly point for lipids and bile acids that are destined for biliary secretion.…”

Section: Lipid Transport To the Canalicular Membranementioning

confidence: 99%

Mechanisms and functional features of polarized membrane traffic in epithelial and hepatic cells

Zegers

Hoekstra

1998

Biochemical Journal

135

View full text Add to dashboard Cite

Epithelial cells express plasma-membrane polarity in order to meet functional requirements that are imposed by their interaction with different extracellular environments. Thus apical and basolateral membrane domains are distinguished that are separated by tight junctions in order to maintain the specific lipid and protein composition of each domain. In hepatic cells, the plasma membrane is also polarized, containing a sinusoidal (basolateral) and a bile canalicular (apical)-membrane domain. Relevant to the biogenesis of these domains are issues concerning sorting, (co-)transport and regulation of transport of domain-specific membrane components. In epithelial cells, specific proteins and lipids, destined for the apical membrane, are sorted in the trans-Golgi network (TGN), which involves their sequestration into cholesterol/sphingolipid 'rafts', followed by 'direct' transport to the apical membrane. In hepatic cells, a direct apical transport pathway also exists, as revealed by transport of sphingolipids from TGN to the apical membrane. This is remarkable, since in these cells numerous apical membrane proteins are 'indirectly' sorted, i.e. they are first transferred to the basolateral membrane prior to their subsequent transcytosis to the apical membrane. This raises intriguing questions as to the existence of specific lipid rafts in hepatocytes. As demonstrated in studies with HepG2 cells, it has become evident that, in hepatic cells, apical transport pathways can be regulated by protein kinase activity, which in turn modulates cell polarity. Finally, an important physiological function of hepatic cells is their involvement in intracellular transport and secretion of bile-specific lipids. Mechanisms of these transport processes, including the role of multidrug-resistant proteins in lipid translocation, will be discussed in the context of intracellular vesicular transport. Taken together, hepatic cell systems provide an important asset to studies aimed at elucidating mechanisms of sorting and trafficking of lipids (and proteins) in polarized cells in general.

show abstract

Glycerophospholipids and cholesterol composition of bile in bile-fistula rats treated with monensin

Cited by 13 publications

References 21 publications

Segregation of Glucosylceramide and Sphingomyelin Occurs in the Apical to Basolateral Transcytotic Route in HepG2 Cells

Segregation of Glucosylceramide and Sphingomyelin Occurs in the Apical to Basolateral Transcytotic Route in HepG2 Cells

Modulation of intrahepatic cholesterol trafficking: evidence by in vivo antisense treatment for the involvement of sterol carrier protein-2 in newly synthesized cholesterol transport into rat bile

Mechanisms and functional features of polarized membrane traffic in epithelial and hepatic cells

Contact Info

Product

Resources

About