Impact of LXR activation on alternatively activated human macrophages
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE158022 | GEO | 2021/04/14
REPOSITORIES: GEO
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Project description:Impact of LXR activation on alternatively activated human macrophages
| PRJNA663777 | ENA
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 LXRM-NM-1 and LXRM-NM-2 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), LXRM-NM-1 and LXRM-NM-2 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 LXRM-NM-1 KO mice. However, only minor changes in expression level were observed for these genes after treatment with T0901317 in myotubes from LXRM-NM-2 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 LXRM-NM-1 KO mice, but not LXRM-NM-2 KO mice. The data suggest that the lipogenic effects of LXRs, as well as the LXR-stimulated cholesterol efflux, are mainly mediated by LXRM-NM-2 in skeletal muscle. To study the importance of each of the receptor subtypes, myotube cultures derived from wild type (WT), LXRa and LXRb knockout (KO) mice were established. Sixteen samples were examined. Half the samples were treated with the unselective LXR agonist T0901317.
2010-03-30 | E-GEOD-13192 | biostudies-arrayexpress
Project description:Macrophage activation must be tightly controlled to prevent overzealous responses that cause self-damage. MicroRNAs have been shown to promote classical macrophage activation by blocking concomitant anti-inflammatory signals and transcription factors, but can also place restraints on activation by preventing excessive TLR-signalling. In contrast, the microRNA profile associated with alternatively activated macrophages and their role in regulating wound-healing or anti-helminthic responses has not yet been described. Utilizing an in vivo model of alternative activation, in which adult Brugia malayi nematodes are surgically implanted in the peritoneal cavity of mice, we examined the profile of microRNA expression in these alternatively activated macrophages and compared this to alternatively activated IL-4 receptor knockout macrophages and thioglycollate elicited macrophages. Peritoneal macrophages from BALB/c wild type or IL-4 receptor knockout mice were elicited with thioglycollate or using nemtodes (peritoneal implant of Brugia malayi). The latter leads to a population of alternatively activated macrophages. Microarray analysis was used to examine the microRNA profile of WT alternatively activated macrophages (n = 4), IL-4 receptor knockout alternatively activated macrophages (n = 4), WT thioglycollate elicited macrophages (n = 3) and IL-4 receptor knockout thioglycollate elicited macrophages (n = 3).
2012-08-07 | E-GEOD-35047 | biostudies-arrayexpress
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 LXRα and LXRβ 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), LXRα and LXRβ 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 LXRα KO mice. However, only minor changes in expression level were observed for these genes after treatment with T0901317 in myotubes from LXRβ 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 LXRα KO mice, but not LXRβ KO mice. The data suggest that the lipogenic effects of LXRs, as well as the LXR-stimulated cholesterol efflux, are mainly mediated by LXRβ in skeletal muscle.
2010-03-31 | GSE13192 | GEO
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.
2009-10-01 | E-MTAB-61 | biostudies-arrayexpress
Project description:Mycobacterium tuberculosis (Mtb) is a life-threatening pathogen in humans. Bacterial infection of macrophages usually triggers strong innate immune mechanisms, including IL-1 cytokine secretion. The newer member of the IL-1 family, IL-36, was recently shown to be involved in cellular defense against Mtb. To unveil the underlying mechanism of IL-36 induced antibacterial activity, we analyzed its role in the regulation of cholesterol metabolism, together with the involvement of Liver X Receptor (LXR) in this process. Here we report that, in Mtb-infected macrophages, IL-36 signaling modulates cholesterol biosynthesis and efflux via LXR. Moreover, IL-36 induces the expression of cholesterol-converting enzymes and the accumulation of LXR ligands, such as oxysterols. Ultimately, both IL-36 and LXR signaling play a role in the regulation of antimicrobial peptides expression and in Mtb growth restriction. These data provide novel evidence for the importance of IL‑36 and cholesterol metabolism mediated by LXR in cellular host defense against Mtb.
2018-02-14 | GSE103092 | GEO
Project description:Background: Obesity is associated with infiltration of macrophages into adipose tissue. Adipose macrophages may contribute to an elevated inflammatory status by secreting a variety of pro-inflammatory mediators, including TNFalpha and IL-6. Recent data suggest that during diet-induced obesity the phenotype of adipose-resident macrophages changes from alternatively activated macrophages towards a more classical and pro-inflammatory phenotype. Here, we explore the effect of PPARγ-activation on obesity-induced inflammation in 129SV mice fed a high fat diet for 20 weeks. High fat feeding increased bodyweight gain, adipose tissue mass and liver triglycerides. Rosiglitazone treatment further increased adipose mass, reduced liver triglycerides and changed adipose tissue morphology towards smaller adipocytes. Surprisingly, rosiglitazone markedly increased the number of macrophages in adipose tissue, as shown by immunohistochemical analysis and quantification of macrophage marker genes CD68 and F4/80+. In adipose tissue, markers for classically activated macrophages including IL-18 were down regulated whereas markers characteristic for alternatively activated macrophages (Arginase 1, IL-10) were up regulated by rosiglitazone. Importantly, conditioned media from rosiglitazone-treated alternatively activated macrophages neutralized the inhibitory effect of macrophages on 3T3-L1 adipocyte differentiation, suggesting that alternatively activated macrophages may be involved in mediating the effects of rosiglitazone on adipose tissue morphology and mass. Our results suggest that short term rosiglitazone treatment increases infiltration of alternatively activated macrophages in adipose tissue. The alternatively activated macrophages might play a role in PPARγ-dependent expansion and remodeling of adipose tissue. Keywords: metabolic state analysis
2008-04-29 | GSE11295 | GEO
Project description:The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice is dependent on LXR and correlates with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the role of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as PPAR signaling pathways, and subsequent ChIP-seq mapping of PPARM-NM-1 binding demonstrated binding of PPARM-NM-1 to 71-88% of the identified LXR:RXR binding sites. Sequence analysis of shared binding regions combined with sequential ChIP on selected sites indicate that LXR:RXR and PPARM-NM-1:RXR bind to degenerate response elements in a mutually exclusive manner. Together our findings suggest extensive and unexpected cross-talk between hepatic LXR and PPARM-NM-1 at the level of binding to shared genomic sites LXR, RXR, PPARalpha and RNA Polymerase II ChIP-seq on livers from female C57BL/6 wild-type and/or LXRM-NM-1/M-NM-2-deficient mice (13 weeks of age, n=1) treated by oral gavage once daily for 14 days with the RXR agonist bexarotene (100 mg/kg body weight [mpk], in 1% carboxymethylcellulose), the LXR agonist T0901317 (T09, 30 mpk) or vehicle alone.
2012-01-31 | E-GEOD-35262 | biostudies-arrayexpress
Project description:Macrophage activation must be tightly controlled to prevent overzealous responses that cause self-damage. MicroRNAs have been shown to promote classical macrophage activation by blocking concomitant anti-inflammatory signals and transcription factors, but can also place restraints on activation by preventing excessive TLR-signalling. In contrast, the microRNA profile associated with alternatively activated macrophages and their role in regulating wound-healing or anti-helminthic responses has not yet been described. Utilizing an in vivo model of alternative activation, in which adult Brugia malayi nematodes are surgically implanted in the peritoneal cavity of mice, we examined the profile of microRNA expression in these alternatively activated macrophages and compared this to alternatively activated IL-4 receptor knockout macrophages and thioglycollate elicited macrophages.
2012-08-08 | GSE35047 | GEO
Project description:The Liver X Receptors (LXRs) play important roles in multiple metabolic pathways, including fatty acid, cholesterol, carbohydrate and energy metabolism. To expand the knowledge of the functions of LXR signaling during embryonic development, we performed a whole-genome microarray analysis of Lxr target genes in zebrafish larvae treated with either one of the synthetic LXR ligands T0901317 or GW3965. Assessment of the biological processes enriched by differentially expressed genes revealed a prime role for Lxr in regulating lipid metabolic processes, similarly to the function of LXR in mammals. In addition, exposure to the Lxr ligands induced changes in expression of genes in the neural retina and lens of the zebrafish eye, including the photoreceptor guanylate cyclase activators and lens gamma crystallins, suggesting a potential novel role for Lxr in modulating the transcription of genes associated with visual function in zebrafish. The regulation of expression of metabolic genes was phenotypically reflected in an increased absorption of yolk in the zebrafish larvae, and changes in the expression of genes involved in visual perception were associated with morphological alterations in the retina and lens of the developing zebrafish eye. The regulation of expression of both lipid metabolic and eye specific genes was sustained in 1 month old fish. The transcriptional networks demonstrated several conserved effects of LXR activation between zebrafish and mammals, and also identified potential novel functions of Lxr, supporting zebrafish as a promising model for investigating the role of Lxr during development.
2016-03-07 | GSE59031 | GEO