Project description:To identify novel LXR target genes, we conducted transcriptional profiling studies using RAW264.7 cells ectopically expressing LXRalpha Total RNA was isolated from RAW264.7 macrophages ectopically expressing LXRalpha as described in Venkateswaran et al. (2000); PNAS 97, 12097-12102. Cells were cultured with DMSO or GW3965 (1 μM) and LG268 (100 nM). Transcriptional profiling was performed at the UCLA microarray core facility using murine Affymetrix 430 2.0 microarrays.
Project description:Liver X receptors (LXRs) are important regulators of cholesterol, lipid and glucose metabolism and have been extensively studied in liver, macrophages and adipose tissue. However, their role in skeletal muscle is not yet fully elucidated and the functional role of each of the LXRalpha (NR1H3) and LXRbeta (NR1H2) subtypes in skeletal muscle is at present unknown. To study the importance of each of the receptor subtypes, myotube cultures derived from wild type (WT), LXRalpha and LXRbeta knockout (KO) mice were established. The present study shows that treatment with the unselective LXR agonist T0901317 increased mRNA levels of LXR target genes such as sterol regulatory element-binding transcription factor 1 (SREBF1), fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1) and ATP-binding cassette transporter A1 (ABCA1) in myotubes established from WT and LXRalpha KO mice. However, only minor changes in expression level were observed for these genes after treatment with T0901317 in myotubes from LXRbeta KO mice. Gene expression analysis using Affymetrix NuGO Genechip arrays showed that few other genes than the classical, well known LXR target genes were regulated by LXR in skeletal muscle. Furthermore, functional studies using radiolabeled substrates showed that treatment with T0901317 increased lipogenesis and apoA1 dependent cholesterol efflux, in myotubes from WT and LXRalpha KO mice, but not LXRbeta KO mice. The data suggest that the lipogenic effects of LXRs, as well as the LXR-stimulated cholesterol efflux, are mainly mediated by LXRbeta in skeletal muscle.
Project description:Bone marrow derived macrophages were isolated from C57BL/6J (LXR positive) and LXRalpha +LXRbeta double knockout mice (DKO) that had been treated with vehicle, Kado2-lipid A (KLA, and inflammatory stimulus), acetylated LDL (AcLDL, a mimic of pro-atherogenic lipoprotein particles) and GW3965 (GW, a synthetic LXR agonist) for 17 hours. Following treatment RNA was isolated and RNA-Seq was performed.
Project description:Effect of LXR activation on LPS-induced inflammatory response in immortalized bone marrow macrophages from LXRa/b knockout mice stably expressing LXR wildtype, K328R/K434R or L439A/E441A mutant
