Apolipoprotein B epitopes are present in nuclear preparations of human and mouse cells.
We previously showed that a native very low-density lipoprotein (VLDL)- and low-density lipoprotein (LDL)-rich mix induces global changes in DNA methylation in cultured THP-1 human macrophages. The exact molecular mechanisms for this response are not yet known. Previous studies showed that apolipoprotein B (ApoB) or its fragments can be localized in nuclei following cellular uptake, thus suggesting that ApoB may have a chromatin-modifying activity. To verify this hypothesis, we assessed whether ApoB epitopes are detected in THP-1 and mouse cell nuclei. Using a combination of immunoblotting, immunocytochemistry and chromatin immunoprecipitation, we showed that ApoB epitopes are present in THP-1 cell and mouse monocyte/macrophage nuclear fractions, but are perinuclear rather than intranuclear. Our results are not consistent with a direct chromatin-ApoB interaction as an underlying mechanism for the observed epigenetic responses to lipoproteins in THP-1 cells.
Døssing
Kristina
K
Department of Clinical Biochemistry, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
Zaina
Silvio
S
D000818:Animals; D001055:Apolipoproteins B / Q000276:immunology / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D000939:Epitopes; D006801:Humans; D017737:Macrophages, Peritoneal / Q000378:metabolism; D051379:Mice; D009000:Monocytes / Q000378:metabolism
D001055:Apolipoproteins B; D002843:Chromatin; D000939:Epitopes