Project description:Lipoprotein lipase (LPL) is an extracellular lipase that preferentially hydrolyses triglycerides in triglyceride-rich lipoproteins within the circulation. LPL expression in macrophages contributes to atherosclerosis. In addition, the hydrolysis products liberated from lipoprotein lipids by LPL causes lipid accumulation and impairs cholesterol efflux ability in macrophages. However, the effects of LPL hydrolysis products in modulating the transcript profiles within macrophages and their roles in foam cell formation are not completely understood. We performed microarray analyses on THP-1 macrophages incubated with LPL hydrolysis products to identify differentially expressed genes.
Project description:Lipoprotein lipid hydrolysis products generated by lipoprotein lipase (LPL) (herein, HP) can contribute to the conversion of macrophages into foam cells, but the molecular processes are not well understood. We previously reported that HP from total lipoproteins significantly changed the transcriptome of human macrophages, including an increased representation of small nucleolar RNAs. Cellular stress within cardiomyocytes was previously reported to increase the expression of small nucleolar RNAs through an increase of reactive oxygen species (ROS) generation by NADPH oxidase (NOX). Thus, we hypothesized that the HP induced ROS production through NOX activity, resulting in changes to small RNA transcripts. We examined changes to small RNA expression using RNA-seq in the absence or presence of HP, and whether those changes could be reversed by NOX inhibition. We identified eight differentially expressed small RNAs: three with differed expression in response to HP, and five with differed expression in response to NOX inhibition in the presence of HP.
Project description:Triglyceride-rich lipoproteins and their remnants contribute to atherosclerosis, possibly by carrying remnant cholesterol and/or by exerting a pro-inflammatory effect on macrophages. Nevertheless, little is known about how macrophages process triglyceride-rich lipoproteins. We show that uptake by macrophages of VLDL-sized emulsion particles is dependent on the enzyme lipoprotein lipase via its C-terminal domain. Subsequent internalization of VLDL-triglycerides by macrophages is carried out by caveolae-mediated endocytosis, followed by hydrolysis by lysosomal acid lipase. STARD3 is required for the transfer of lysosomal fatty acids to the ER for lipid storage, while NPC1 likely is involved in promoting the extracellular efflux of fatty acids. Our data provide novel insights into how macrophages process VLDL-derived triglycerides and suggest that macrophages have the remarkable capacity to excrete internalized triglycerides as fatty acids.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Changes to small RNA expression in macrophages in response to very low-density lipoprotein lipid hydrolysis by lipoprotein lipase and NADPH oxidase inhibition
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
