cytosporone-b and Inflammation

The orphan nuclear receptor Nur77 is involved in diverse cellular processes such as inflammation, proliferation, differentiation and survival. Stimuli like lipopolysaccharide (LPS) and tumor necrosis factor (TNF) increase Nur77 expression in human and murine macrophages, and it has been proposed that Nur77 plays a major role in dampening the inflammatory response. Here, we evaluated the expression and function of Nur77 in human anti-inflammatory and pro-inflammatory macrophages derived from blood monocytes cultured with macrophage colony-stimulating factor (M-MDMs) or granulocyte/macrophage colony-stimulating factor (GM-MDMs), respectively. Nur77 mRNA expression was significantly enhanced in M-MDMs compared with GM-MDMs, both constitutively and upon exposure to Toll-like receptor (TLR)2, 3, and 4 ligands. Nur77 activation with the agonist Cytosporone B (CsnB) significantly suppressed the production of TNF, interleukin (IL)-1β, IL-6, and IL-8 in GM-MDMs stimulated with LPS. In contrast, it tended to enhance the production of the anti-inflammatory cytokine IL-10. This effect was associated with reduced NF-κB p65 nuclear translocation. Similarly, Nur77 knockdown enhanced TNF production in GM-MDMs. CsnB effectively stimulated the transactivation activity of Nur77 in M-MDMs, but it did not alter cytokine synthesis or p65 nuclear translocation. However, Nur77 seemed to have a role in maintaining the anti-inflammatory profile of M-MDMs, since Nur77-deficient M-MDMs constitutively produced higher levels of TNF transcripts. Thus, in the absence of exogenous agonists, Nur77 activity favors the anti-inflammatory function of M-MDMs, whereas agonistic activation of this receptor preferentially drives attenuation of inflammation in inflammatory macrophages.

Topics: Cytokines; Humans; Inflammation; Lipopolysaccharides; Macrophage Colony-Stimulating Factor; Macrophages; NF-kappa B; Nuclear Receptor Subfamily 4, Group A, Member 1; Phenylacetates; Tumor Necrosis Factor-alpha

Inflammation is a pivotal pathological factor in colorectal cancer (CRC) initiation and progression, and modulating this inflammatory state has the potential to ameliorate disease progression. NR4A receptors have emerged as key regulators of inflammatory pathways that are important in CRC. Here, we have examined the effect of NR4A agonist, Cytosporone B (CsnB), on colorectal tissue integrity and its effect on the inflammatory profile in CRC tissue ex vivo. Here, we demonstrate concentrations up 100 μM CsnB did not adversely affect tissue integrity as measured using transepithelial electrical resistance, histology and crypt height. Subsequently, we reveal through the use of a cytokine/chemokine array, ELISA and qRT-PCR analysis that multiple pro-inflammatory mediators were significantly increased in CRC tissue compared to control tissue, which were then attenuated with the addition of CsnB (such as IL-1β, IL-8 and TNFα). Lastly, stratification of the data revealed that CsnB especially alters the inflammatory profile of tumours derived from males who had not undergone chemoradiotherapy. Thus, this study demonstrates that NR4A agonist CsnB does not adversely affect colon tissue structure or functionality and can attenuate the pro-inflammatory state of human CRC tissue ex vivo.

Topics: Adult; Aged; Aged, 80 and over; Chemokines; Colorectal Neoplasms; Cytokines; Female; Humans; Inflammation; Inflammation Mediators; Male; Middle Aged; Nuclear Receptor Subfamily 4, Group A, Member 1; Phenylacetates

Chronically activated CD4

Topics: Animals; Anti-Inflammatory Agents; Antibodies; Arthritis, Experimental; Arthritis, Rheumatoid; CD4-Positive T-Lymphocytes; Collagen Type II; Cytokines; Female; Humans; Inflammation; Male; Mice; Mice, Inbred DBA; Phenylacetates; Receptors, Cytoplasmic and Nuclear; Retinoids; Synovial Fluid; Thiazoles; Thiosemicarbazones; Transcription, Genetic

Monocytes are central to the physiopathology of arthritis, but their roles in progression and resolution of the disease remain to be clarified. Using NR4A1

Topics: Animals; Anti-Inflammatory Agents; Antigens, Ly; Arthritis; Cells, Cultured; Disease Models, Animal; Female; Humans; Inflammation; Joints; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; Nuclear Receptor Subfamily 4, Group A, Member 1; Phenylacetates; T-Lymphocytes, Regulatory

Hypercholesterolaemia and inflammation are correlated with atherogenesis. Orphan nuclear receptor NR4A1, as a key regulator of inflammation, is closely associated with lipid levels in vivo. However, the mechanism by which lipids regulate NR4A1 expression remains unknown. We aimed to elucidate the underlying mechanism of NR4A1 expression in monocytes during hypercholesterolaemia, and reveal the potential role of NR4A1 in hypercholesterolaemia-induced circulating inflammation. Circulating leucocytes were collected from blood samples of 139 patients with hypercholesterolaemia and 139 sex- and age-matched healthy subjects. We found that there was a low-grade inflammatory state and higher expression of NR4A1 in patients. Both total cholesterol and low-density lipoprotein cholesterol levels in plasma were positively correlated with NR4A1 mRNA level. ChIP revealed that acetylation of histone H3 was enriched in the NR4A1 promoter region in patients. Human mononuclear cell lines THP-1 and U937 were treated with cholesterol. Supporting our clinical observations, cholesterol enhanced p300 acetyltransferase and decreased HDAC7 (histone deacetylase 7) recruitment to the NR4A1 promoter region, resulting in histone H3 hyperacetylation and further contributing to NR4A1 up-regulation in monocytes. Moreover, cytosporone B, an NR4A1 agonist, completely reversed cholesterol-induced IL-6 (interleukin 6) and MCP-1 (monocyte chemoattractant protein 1) expression to below basal levels, and knockdown of NR4A1 expression by siRNA not only mimicked, but also exaggerated the effects of cholesterol on inflammatory biomarker up-regulation. Thus we conclude that histone acetylation contributes to the regulation of NR4A1 expression in hypercholesterolaemia, and that NR4A1 expression reduces hypercholesterolaemia-induced inflammation.

Topics: Acetylation; Adult; Aged; Binding Sites; Case-Control Studies; Chemokine CCL2; Cholesterol; Female; Gene Expression Regulation; Histone Deacetylases; Histones; Humans; Hypercholesterolemia; Inflammation; Inflammation Mediators; Interleukin-6; Male; Middle Aged; Monocytes; Nuclear Receptor Subfamily 4, Group A, Member 1; p300-CBP Transcription Factors; Phenylacetates; Promoter Regions, Genetic; Protein Processing, Post-Translational; RNA Interference; RNA, Messenger; Transfection; U937 Cells

It is clear that lipid disorder and inflammation are associated with cardiovascular diseases and underlying atherosclerosis. Nur77 has been shown to be involved in inflammatory response and lipid metabolism.. Here, we explored the role of Nur77 in atherosclerotic plaque progression in apoE(-/-) mice fed a high-fat/high cholesterol diet.. The Nur77 gene, a nuclear hormone receptor, was highly induced by treatment with Cytosporone B (Csn-B, specific Nur77 agonist), recombinant plasmid over-expressing Nur77 (pcDNA-Nur77), while inhibited by treatment with siRNAs against Nur77 (si-Nur77) in THP-1 macrophage-derived foam cells, HepG2 cells and Caco-2 cells, respectively. In addition, the expression of Nur77 was highly induced by Nur77 agonist Csn-B, lentivirus encoding Nur77 (LV-Nur77), while silenced by lentivirus encoding siRNA against Nur77 (si-Nur77) in apoE(-/-) mice fed a high-fat/high cholesterol diet, respectively. We found that increased expression of Nur77 reduced macrophage-derived foam cells formation and hepatic lipid deposition, downregulated gene levels of inflammatory molecules, adhesion molecules and intestinal lipid absorption, and decreases atherosclerotic plaque formation.. These observations provide direct evidence that Nur77 is an important nuclear hormone receptor in regulation of atherosclerotic plaque formation and thus represents a promising target for the treatment of atherosclerosis.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Blotting, Western; Caco-2 Cells; Cell Line, Tumor; Cholesterol, Dietary; Diet, High-Fat; Disease Progression; Foam Cells; Gene Expression; Hep G2 Cells; Humans; Inflammation; Lipid Metabolism; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nuclear Receptor Subfamily 4, Group A, Member 1; Phenylacetates; Plaque, Atherosclerotic; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference