title: The effect of old age on apolipoprotein E and its receptors in rat liver.
abstract: Apolipoprotein E (apoE) is associated with aging and some age-related diseases. The majority of apoE is produced by hepatocytes for the receptor-mediated uptake of lipoproteins. Here, the effects of age on the hepatic expression and distribution of apoE and its receptors were determined using immunofluorescence, Western blots, and quantitative PCR in rat liver tissue and isolated hepatocytes. The expression of apoE mRNA and protein was not influenced significantly by aging. Immunofluorescence studies in isolated hepatocytes showed that apoE was more likely to be co-localized with early endosomes, golgi, and microtubules in isolated old hepatocytes. The mRNA expression of the receptor involved in sequestration of apoE, heparan sulfate proteoglycan was reduced in old age, without any significant effect on the expression of either the low-density lipoprotein receptor or low density-lipoprotein receptor-related protein. Old age is associated with changes in hepatic apoE intracellular trafficking and heparan sulfate proteoglycan expression that might contribute to age-related disease.
authors.affiliation: ANZAC Research Institute, University of Sydney, Sydney, Australia.
authors.forename: Tharani
authors.initials: T
authors.lastname: Sabaretnam
authors.forename: Jennifer
authors.initials: J
authors.lastname: O'Reilly
authors.forename: Leonard
authors.initials: L
authors.lastname: Kritharides
authors.forename: David G
authors.initials: DG
authors.lastname: Le Couteur
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001057:Apolipoproteins E / Q000378:metabolism*; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011973:Receptors, LDL / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: D001057:Apolipoproteins E; D019812:Heparan Sulfate Proteoglycans; D012333:RNA, Messenger; D011973:Receptors, LDL