title: Postprandial phase time influences the uptake of TAG from postprandial TAG-rich lipoproteins by THP-1 macrophages.
abstract: Postprandial TAG-rich lipoproteins (TRL) can be taken up by macrophages, leading to the formation of foam cells, probably via receptor-mediated pathways. The present study was conducted to investigate whether the postprandial time point at which TRL are collected modulates this process. A meal containing refined olive oil was given to nine healthy young men and TRL were isolated from their serum at 2, 4 and 6 h postprandially. The lipid class and apoB compositions of TRL were determined by HPLC and SDS-PAGE, respectively. The accumulation of lipids in macrophages was determined after the incubation of THP-1 macrophages with TRL. The gene expression of candidate receptors was measured by real-time PCR. The highest concentrations of TAG, apoB48 and apoB100 in TRL were observed at 2 h after the consumption of the test meal. However, excessive intracellular TAG accumulation in THP-1 macrophages was observed in response to incubation with TRL isolated at 4 h, when their particle size (estimated as the TAG:apoB ratio) was intermediate. The abundance of mRNA transcripts in macrophages in response to incubation with TRL was down-regulated for LDL receptor (LDLR), slightly up-regulated for VLDL receptor and remained unaltered for LDLR-related protein, but no effect of the postprandial time point was observed. In contrast, the mRNA expression of scavenger receptors SRB1, SRA2 and CD36 was higher when cells were incubated with TRL isolated at 4 h after the consumption of the test meal. In conclusion, TRL led to excessive intracellular TAG accumulation in THP-1 macrophages, which was greater when cells were incubated with intermediate-sized postprandial TRL isolated at 4 h and was associated with a significant increase in the mRNA expression of scavenger receptors.
authors.affiliation: Nutrition and Lipid Metabolism, Instituto de la Grasa (CSIC),Avenida Padre García Tejero, 4,41012Seville,Spain.
authors.forename: Rosana
authors.initials: R
authors.lastname: Cabello-Moruno
authors.affiliation: Nutrition and Lipid Metabolism, Instituto de la Grasa (CSIC),Avenida Padre García Tejero, 4,41012Seville,Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Sinausia
authors.affiliation: Department of Comparative Biomedical Sciences,The Royal Veterinary College,Royal College Street,LondonNW1 0TU,UK.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Botham
authors.affiliation: Emergencies Services, General Hospital, HHUU Virgen del Rocío, Avenida Manuel Siurot s/n,41013Seville,Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Montero
authors.affiliation: Department of Comparative Biomedical Sciences,The Royal Veterinary College,Royal College Street,LondonNW1 0TU,UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Avella
authors.affiliation: Nutrition and Lipid Metabolism, Instituto de la Grasa (CSIC),Avenida Padre García Tejero, 4,41012Seville,Spain.
authors.forename: Javier S
authors.initials: JS
authors.lastname: Perona
mesh_terms: D000328:Adult; D018955:CD36 Antigens / Q000235:genetics; D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood*; D008264:Macrophages / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D010316:Particle Size; D019518:Postprandial Period / Q000502:physiology*; D012333:RNA, Messenger / Q000097:blood; D011973:Receptors, LDL / Q000235:genetics; D051117:Scavenger Receptors, Class A / Q000235:genetics; D051122:Scavenger Receptors, Class B / Q000235:genetics; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
chemical_list: D018955:CD36 Antigens; D008074:Lipoproteins; D012333:RNA, Messenger; D011973:Receptors, LDL; C495124:SCARB1 protein, human; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B; D014280:Triglycerides; C036053:VLDL receptor