| First Author | Bharadwaj KG | Year | 2010 |
| Journal | J Biol Chem | Volume | 285 |
| Issue | 49 | Pages | 37976-86 |
| PubMed ID | 20852327 | Mgi Jnum | J:167341 |
| Mgi Id | MGI:4867817 | Doi | 10.1074/jbc.M110.174458 |
| Citation | Bharadwaj KG, et al. (2010) Chylomicron- and VLDL-derived lipids enter the heart through different pathways: in vivo evidence for receptor- and non-receptor-mediated fatty acid uptake. J Biol Chem 285(49):37976-86 |
| abstractText | Lipids circulate in the blood in association with plasma lipoproteins and enter the tissues either after hydrolysis or as non-hydrolyzable lipid esters. We studied cardiac lipids, lipoprotein lipid uptake, and gene expression in heart-specific lipoprotein lipase (LpL) knock-out (hLpL0), CD36 knock-out (Cd36(-/-)), and double knock-out (hLpL0/Cd36(-/-)-DKO) mice. Loss of either LpL or CD36 led to a significant reduction in heart total fatty acyl-CoA (control, 99.5 +/- 3.8; hLpL0, 36.2 +/- 3.5; Cd36(-/-), 57.7 +/- 5.5 nmol/g, p < 0.05) and an additive effect was observed in the DKO (20.2 +/- 1.4 nmol/g, p < 0.05). Myocardial VLDL-triglyceride (TG) uptake was reduced in the hLpL0 (31 +/- 6%) and Cd36(-/-) (47 +/- 4%) mice with an additive reduction in the DKO (64 +/- 5%) compared with control. However, LpL but not CD36 deficiency decreased VLDL-cholesteryl ester uptake. Endogenously labeled mouse chylomicrons were produced by tamoxifen treatment of beta-actin-MerCreMer/LpL(flox/flox) mice. Induced loss of LpL increased TG levels >10-fold and reduced HDL by >50%. After injection of these labeled chylomicrons in the different mice, chylomicron TG uptake was reduced by approximately 70% and retinyl ester by approximately 50% in hLpL0 hearts. Loss of CD36 did not alter either chylomicron TG or retinyl ester uptake. LpL loss did not affect uptake of remnant lipoproteins from ApoE knock-out mice. Our data are consistent with two pathways for fatty acid uptake; a CD36 process for VLDL-derived fatty acid and a non-CD36 process for chylomicron-derived fatty acid uptake. In addition, our data show that lipolysis is involved in uptake of core lipids from TG-rich lipoproteins. |
