Linked Life Data

21127258

Source:http://linkedlifedata.com/resource/pubmed/id/21127258

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2011-1-31
pubmed:abstractText
Apolipoprotein (apo) A-IV overexpression enhances chylomicron (CM) assembly and secretion in newborn swine intestinal epithelial cells by producing larger particles (Lu S, Yao Y, Cheng X, Mitchell S, Leng S, Meng S, Gallagher JW, Shelness GS, Morris GS, Mahan J, Frase S, Mansbach CM, Weinberg RB, Black DD. J Biol Chem 281: 3473-3483, 2006). To determine the impact of apo A-IV on microsomal triglyceride transfer protein (MTTP), IPEC-1 cell lines containing a tetracycline-regulatable expression system were used to overexpress native swine apo A-IV and "piglike" human apo A-IV, a mutant human apo A-IV with deletion of the EQQQ-rich COOH-terminus, previously shown to upregulate basolateral triglyceride (TG) secretion 5-fold and 25-fold, respectively. Cells were incubated 24 h with and without doxycycline and oleic acid (OA, 0.8 mM). Overexpression of the native swine apo A-IV and piglike human apo A-IV increased MTTP lipid transfer activity by 39.7% (P = 0.006) and 53.6% (P = 0.0001), respectively, compared with controls. Changes in mRNA and protein levels generally paralleled changes in activity. Interestingly, native swine apo A-IV overexpression also increased MTTP large subunit mRNA, protein levels, and lipid transfer activity in the absence of OA, suggesting a mechanism not mediated by lipid absorption. Overexpression of piglike human apo A-IV significantly increased partitioning of radiolabeled OA from endoplasmic reticulum (ER) membrane to lumen, suggesting increased net transfer of membrane TG to luminal particles. These results suggest that the increased packaging of TG into nascent CMs in the ER lumen, induced by apo A-IV, is associated with upregulation of MTTP activity at the pretranslational level. Thus MTTP is regulated by apo A-IV in a manner to promote increased packaging of TG into the CM core, which may be important in neonatal fat absorption.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1522-1547
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
300
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
G357-63
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Regulation of microsomal triglyceride transfer protein by apolipoprotein A-IV in newborn swine intestinal epithelial cells.
pubmed:affiliation
Children's Foundation Research Center of Memphis, Le Bonheur Children's Medical Center, Rm. 401, W. Patient Tower, 50 N. Dunlap, Memphis, TN 38103, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural