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Generating Ceramide from Sphingomyelin by Alkaline Sphingomyelinase in the Gut Enhances Sphingomyelin-Induced Inhibition of Cholesterol Uptake in Caco-2 Cells.

Feng, Dan LU ; Ohlsson, Lena LU ; Ling, Wenhua; Nilsson, Åke LU and Duan, Rui-Dong LU (2010) In Digestive Diseases and Sciences Mar 4. p.3377-3383
Abstract
BACKGROUND: Sphingomyelin (SM) is present in dietary products and cell plasma membranes. We previously showed that dietary SM inhibited cholesterol absorption in rats. In the intestinal tract, SM is mainly hydrolyzed by alkaline sphingomyelinase (alk-SMase) to ceramide. AIMS: We investigated the influence of SM and its hydrolytic products ceramide and sphingosine on cholesterol uptake in intestinal Caco-2 cells. METHODS: Micelles containing bile salt, monoolein, and (14)C-cholesterol were prepared with or without SM, ceramide, or sphingosine. The micelles were incubated with Caco-2 cells, and uptake of radioactive cholesterol was quantified. RESULTS: We found that confluent monolayer Caco-2 cells expressed NPC1L1, and the uptake of... (More)
BACKGROUND: Sphingomyelin (SM) is present in dietary products and cell plasma membranes. We previously showed that dietary SM inhibited cholesterol absorption in rats. In the intestinal tract, SM is mainly hydrolyzed by alkaline sphingomyelinase (alk-SMase) to ceramide. AIMS: We investigated the influence of SM and its hydrolytic products ceramide and sphingosine on cholesterol uptake in intestinal Caco-2 cells. METHODS: Micelles containing bile salt, monoolein, and (14)C-cholesterol were prepared with or without SM, ceramide, or sphingosine. The micelles were incubated with Caco-2 cells, and uptake of radioactive cholesterol was quantified. RESULTS: We found that confluent monolayer Caco-2 cells expressed NPC1L1, and the uptake of cholesterol in the cells was inhibited by ezetimibe, a specific inhibitor of NPC1L1. Incorporation of SM in the cholesterol micelles inhibited cholesterol uptake dose-dependently; 38% inhibition occurred at an equal mole ratio of SM and cholesterol. The inhibition was further enhanced to 45% by pretreating the cholesterol/SM micelles with recombinant alk-SMase, which hydrolyzed SM in the micelles by 85%, indicating ceramide has stronger inhibitory effects on cholesterol uptake. To confirm this, we further replaced SM in the micelles with ceramide and sphingosine, and found that at equal mole ratio to cholesterol, ceramide exhibited stronger inhibitory effect (50% vs 38%) on cholesterol uptake than SM, whereas sphingosine only had a weak effect at high concentrations. CONCLUSION: Both SM and ceramide inhibit cholesterol uptake, the effect of ceramide being stronger than that of SM. Alk-SMase enhances SM-induced inhibition of cholesterol uptake by generating ceramide in the intestinal lumen. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Digestive Diseases and Sciences
volume
Mar 4
pages
3377 - 3383
publisher
Springer
external identifiers
  • wos:000284066200011
  • pmid:20393874
  • scopus:78649327270
ISSN
1573-2568
DOI
10.1007/s10620-010-1202-9
language
English
LU publication?
yes
id
bcbb7fce-2856-4e6e-857e-657fffe43a66 (old id 1595265)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/20393874?dopt=Abstract
date added to LUP
2010-05-04 15:45:44
date last changed
2018-05-29 10:37:13
@article{bcbb7fce-2856-4e6e-857e-657fffe43a66,
  abstract     = {BACKGROUND: Sphingomyelin (SM) is present in dietary products and cell plasma membranes. We previously showed that dietary SM inhibited cholesterol absorption in rats. In the intestinal tract, SM is mainly hydrolyzed by alkaline sphingomyelinase (alk-SMase) to ceramide. AIMS: We investigated the influence of SM and its hydrolytic products ceramide and sphingosine on cholesterol uptake in intestinal Caco-2 cells. METHODS: Micelles containing bile salt, monoolein, and (14)C-cholesterol were prepared with or without SM, ceramide, or sphingosine. The micelles were incubated with Caco-2 cells, and uptake of radioactive cholesterol was quantified. RESULTS: We found that confluent monolayer Caco-2 cells expressed NPC1L1, and the uptake of cholesterol in the cells was inhibited by ezetimibe, a specific inhibitor of NPC1L1. Incorporation of SM in the cholesterol micelles inhibited cholesterol uptake dose-dependently; 38% inhibition occurred at an equal mole ratio of SM and cholesterol. The inhibition was further enhanced to 45% by pretreating the cholesterol/SM micelles with recombinant alk-SMase, which hydrolyzed SM in the micelles by 85%, indicating ceramide has stronger inhibitory effects on cholesterol uptake. To confirm this, we further replaced SM in the micelles with ceramide and sphingosine, and found that at equal mole ratio to cholesterol, ceramide exhibited stronger inhibitory effect (50% vs 38%) on cholesterol uptake than SM, whereas sphingosine only had a weak effect at high concentrations. CONCLUSION: Both SM and ceramide inhibit cholesterol uptake, the effect of ceramide being stronger than that of SM. Alk-SMase enhances SM-induced inhibition of cholesterol uptake by generating ceramide in the intestinal lumen.},
  author       = {Feng, Dan and Ohlsson, Lena and Ling, Wenhua and Nilsson, Åke and Duan, Rui-Dong},
  issn         = {1573-2568},
  language     = {eng},
  pages        = {3377--3383},
  publisher    = {Springer},
  series       = {Digestive Diseases and Sciences},
  title        = {Generating Ceramide from Sphingomyelin by Alkaline Sphingomyelinase in the Gut Enhances Sphingomyelin-Induced Inhibition of Cholesterol Uptake in Caco-2 Cells.},
  url          = {http://dx.doi.org/10.1007/s10620-010-1202-9},
  volume       = {Mar 4},
  year         = {2010},
}