Transport of lipoprotein lipase across endothelial cells

Journal Article · Fri Mar 15 04:00:00 EST 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.6.2254· OSTI ID:5030325

Saxena, U; Klein, M G; Goldberg, I J ^[1]

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1. Columbia Univ., New York, NY (United States)

Lipoprotein lipase (LPL), synthesized in muscle and fat, hydrolyzes plasma triglycerides primarily while bound to luminal endothelial cell surfaces. To obtain information about the movement of LPL from the basal to the luminal endothelial cell surface, the authors studied the transport of purified bovine milk LPL across bovine aortic endothelial cell monolayers. {sup 125}I-labeled LPL ({sup 125}I-LPL) added to the basal surface of the monolayers was detected on the apical side of the cells in two compartments: (1) in the medium of the upper chamber, and (2) bound to the apical cell surface. The amount of {sup 125}I-LPL on the cell surface, but not in the medium, reached saturation with time and LPL dose. Catalytically active LPL was transported to the apical surface but very little LPL activity appeared in the medium. Heparinase treatment of the basal cell surface and addition of dextran sulfate to the lower chamber decreased the amount of {sup 125}I-LPL appearing on the apical surface. Similarly, the presence of increasing molar ratios of oleic acid/bovine serum albumin at the basal surface decreased the transport of active LPL across the monolayer. Thus, a saturable transport system, which requires haparan sulfate proteoglycans and is inhibited by high concentrations of free fatty acids on the basal side of the cells, appears to exist for passage of enzymatically active LPL across endothelial cells. They postulate that regulation of LPL transport to the endothelial luminal surface modulates the physiologically active pool of LPL in vivo.

• OSTI ID: 5030325
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 88:6; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADIPOSE TISSUE
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
BODY
CARBOXYLESTERASES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CONNECTIVE TISSUE
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENDOTHELIUM
ENZYMES
ESTERASES
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LIPASES
LIPIDS
LIPOPROTEINS
MEMBRANE TRANSPORT
MEMBRANES
MONOCARBOXYLIC ACIDS
NUCLEI
ODD-EVEN NUCLEI
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
TISSUES
UPTAKE