Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages
Apolipoprotein E-receptor-mediated pathways are the main routes by which macrophages take up chylomicron remnants, but uptake may also be mediated by receptor-independent routes. To investigate these mechanisms, triacylglycerol (TG) accumulation induced by apolipoprotein-free chylomicron remnant-l...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2012-01-01
|
| Series: | International Journal of Vascular Medicine |
| Online Access: | http://dx.doi.org/10.1155/2012/501954 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832566373956452352 |
|---|---|
| author | Mariarosaria Napolitano Howard S. Kruth Elena Bravo |
| author_facet | Mariarosaria Napolitano Howard S. Kruth Elena Bravo |
| author_sort | Mariarosaria Napolitano |
| collection | DOAJ |
| description | Apolipoprotein E-receptor-mediated pathways are the main routes by which macrophages take up chylomicron remnants, but uptake may also be mediated by receptor-independent routes. To investigate these mechanisms, triacylglycerol (TG) accumulation induced by apolipoprotein-free chylomicron remnant-like particles (CRLPw/o) in human monocyte-derived macrophages was evaluated. Macrophage TG content increased about 5-fold after incubation with
CRLPw/o, and this effect was not reduced by the inhibition of phagocytosis, macropinocytosis, apolipoprotein E function, or proteoglycan bridging.
The role of lipases, including lipoprotein lipase, cholesteryl ester hydrolase, and secretory (sPLA2) and cytosolic phospholipase A2, was studied using [3H]TG-labelled CRLPw/o. Total cell radioactivity after incubation with [3H]TG CRLPw/o was reduced by 15–30% by inhibitors of lipoprotein lipase and cholesteryl ester hydrolase and by about 45% by inhibitors of sPLA2 and cytosolic PLA2 . These results suggest that macrophage lipolytic enzymes mediate the internalization of postprandial TG-rich lipoproteins and that sPLA2 and cytosolic PLA2, play a more important role than extracellular lipoprotein lipase-mediated TG hydrolysis. |
| format | Article |
| id | doaj-art-e4545c6e7ab7423e85818729e2938cf7 |
| institution | Kabale University |
| issn | 2090-2824 2090-2832 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Vascular Medicine |
| spelling | doaj-art-e4545c6e7ab7423e85818729e2938cf72025-02-03T01:04:26ZengWileyInternational Journal of Vascular Medicine2090-28242090-28322012-01-01201210.1155/2012/501954501954Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human MacrophagesMariarosaria Napolitano0Howard S. Kruth1Elena Bravo2Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, ItalySection of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1422, USADepartment of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, ItalyApolipoprotein E-receptor-mediated pathways are the main routes by which macrophages take up chylomicron remnants, but uptake may also be mediated by receptor-independent routes. To investigate these mechanisms, triacylglycerol (TG) accumulation induced by apolipoprotein-free chylomicron remnant-like particles (CRLPw/o) in human monocyte-derived macrophages was evaluated. Macrophage TG content increased about 5-fold after incubation with CRLPw/o, and this effect was not reduced by the inhibition of phagocytosis, macropinocytosis, apolipoprotein E function, or proteoglycan bridging. The role of lipases, including lipoprotein lipase, cholesteryl ester hydrolase, and secretory (sPLA2) and cytosolic phospholipase A2, was studied using [3H]TG-labelled CRLPw/o. Total cell radioactivity after incubation with [3H]TG CRLPw/o was reduced by 15–30% by inhibitors of lipoprotein lipase and cholesteryl ester hydrolase and by about 45% by inhibitors of sPLA2 and cytosolic PLA2 . These results suggest that macrophage lipolytic enzymes mediate the internalization of postprandial TG-rich lipoproteins and that sPLA2 and cytosolic PLA2, play a more important role than extracellular lipoprotein lipase-mediated TG hydrolysis.http://dx.doi.org/10.1155/2012/501954 |
| spellingShingle | Mariarosaria Napolitano Howard S. Kruth Elena Bravo Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages International Journal of Vascular Medicine |
| title | Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages |
| title_full | Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages |
| title_fullStr | Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages |
| title_full_unstemmed | Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages |
| title_short | Phospholipase A2 Mediates Apolipoprotein-Independent Uptake of Chylomicron Remnant-Like Particles by Human Macrophages |
| title_sort | phospholipase a2 mediates apolipoprotein independent uptake of chylomicron remnant like particles by human macrophages |
| url | http://dx.doi.org/10.1155/2012/501954 |
| work_keys_str_mv | AT mariarosarianapolitano phospholipasea2mediatesapolipoproteinindependentuptakeofchylomicronremnantlikeparticlesbyhumanmacrophages AT howardskruth phospholipasea2mediatesapolipoproteinindependentuptakeofchylomicronremnantlikeparticlesbyhumanmacrophages AT elenabravo phospholipasea2mediatesapolipoproteinindependentuptakeofchylomicronremnantlikeparticlesbyhumanmacrophages |