肠细胞中存在脂质的分泌-再摄取循环
  • 肠细胞内过量的甘油三酯以胞质脂滴(cLD)的形式被暂时储存;
  • 肠道特异性敲除主要脂肪水解酶ATGL(脂肪甘油三酯脂肪酶)及其共激活因子CGI-58,使小鼠肠细胞内积累大量cLD;
  • 这些cLD的积累不是来自肠细胞顶部吸收的食物脂质,ATGL/CGI-58不参与为乳糜微粒合成提供底物的食源性脂质水解;
  • cLD的积累是源于肠细胞基底侧吸收的脂质(血源性),ATGL/CGI-58介导血源性脂质的水解;
  • 小肠细胞中存在脂质的分泌-再摄取循环和2个不同的cLD池。
主编推荐语
mildbreeze
小肠中的脂质吸收对维持全身脂质平衡起着至关重要的作用,肠细胞内过量的甘油三酯以胞质脂滴(cLD)的形式暂时储存,并在两餐之间释放来维持脂质供应。Cell Reports发表的一项小鼠研究表明,小肠细胞中存在两个cLD池,一个是来自肠细胞顶部吸收的食源性脂质,另一个来自肠细胞基底侧再吸收的血液中的脂质,食源性脂质的cLD池为乳糜微粒合成提供底物,分泌进淋巴管的乳糜微粒进入血液循环后被肠细胞再摄取,从而形成脂质的分泌-再摄取循环。
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Cell Reports [IF:8.109]

ATGL/CGI-58-Dependent Hydrolysis of a Lipid Storage Pool in Murine Enterocytes

鼠类肠细胞中脂质储存池的ATGL/CGI-58依赖性水解作用

10.1016/j.celrep.2019.07.030

2019-08-13, Article

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As circulating lipid levels are balanced by the rate of lipoprotein release and clearance from the plasma, lipid absorption in the small intestine critically contributes to the maintenance of whole-body lipid homeostasis. Within enterocytes, excessive triglycerides are transiently stored as cytosolic lipid droplets (cLDs), and their mobilization sustains lipid supply during interprandial periods. Using mice lacking adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) exclusively in the intestine (intestine-specific double KO [iDKO]), we show that ATGL/CGI-58 are not involved in providing substrates for chylomicron synthesis. Massive intestinal cLD accumulation in iDKO mice independent of dietary lipids together with inefficient lipid incorporation into cLDs in the early absorption phase demonstrate the existence of a secretion/re-uptake cycle, corroborating the availability of two diverse cLD pools. This study identified ATGL/CGI-58 as critical players in the catabolism of basolaterally (blood) derived lipids and highlights the necessity to modify the current model of intestinal lipid metabolism.

First Authors:
Melanie Korbelius

Correspondence Authors:
Dagmar Kratky

All Authors:
Melanie Korbelius,Nemanja Vujic,Vinay Sachdev,Sascha Obrowsky,Silvia Rainer,Benjamin Gottschalk,Wolfgang F Graier,Dagmar Kratky

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