Novel prostaglandin D2-derived activators of peroxisome proliferator-activated receptor-γ are formed in macrophage cell cultures

AbstractThe ToxCast in vitro screening program has provided concentration-response bioactivity data across more than a thousand assay endpoints for thousands of chemicals found in our environment and commerce. However, most ToxCast screening assays have evaluated individual biological targets in cancer cell lines lacking integrated physiological functionality (such as receptor signaling, metabolism). We evaluated differentiated HepaRGTM cells, a human liver-derived cell model understood to effectively model physiologically relevant hepatic signaling. Expression of 93 gene transcripts was measured by quantitative polymerase chain reaction using Fluidigm 96.96 dynamic arrays in response to 1060 chemicals tested in eight-point concentration-response. A Bayesian framework quantitatively modeled chemical-induced changes in gene expression via six transcription factors including: aryl hydrocarbon receptor, constitutive androstane receptor, pregnane X receptor, farnesoid X receptor, androgen receptor, and peroxisome proliferator-activated receptor alpha. For these chemicals the network model translates transcriptomic data into Bayesian inferences about molecular targets known to activate toxicological adverse outcome pathways. These data also provide new insights into the molecular signaling network of HepaRGTM cell cultures.

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Expression and regulation of sterol 27-hydroxylase (CYP27A1) in human macrophages: a role for RXR and PPARγ ligands

Biochemical Journal ◽

10.1042/bj20041776 ◽

2005 ◽

Vol 385 (3) ◽

pp. 823-830 ◽

Cited By ~ 52

Author(s):

Carmel M. QUINN ◽

Wendy JESSUP ◽

Jenny WONG ◽

Leonard KRITHARIDES ◽

Andrew J. BROWN

Keyword(s):

Human Monocyte ◽

Cell Types ◽

Human Macrophage ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Macrophage Cell ◽

Peroxisome Proliferator Activated Receptor ◽

Protein Levels ◽

Cholesterol Levels ◽

Elimination Pathway

CYP27A1 (sterol 27-hydroxylase) catalyses an important sterol elimination pathway in the human macrophage, and consequently may protect against atherosclerosis. We studied the expression and regulation of CYP27A1 in a human macrophage-like cell-line, THP-1, and primary HMDMs (human monocyte-derived macrophages). In both macrophage cell types, we found that CYP27A1 expression is independent of cellular cholesterol levels and of LXR (liver X receptor)-dependent control of transcription. However, the RXR (retinoid X receptor) ligand, 9-cis-retinoic acid, upregulates CYP27A1 expression. Of the RXR heterodimeric partners tested, PPAR (peroxisome-proliferator-activated receptor) γ ligands significantly increased CYP27A1 mRNA levels. Its reversal by a PPARγ antagonist demonstrated the specificity of this effect. Interestingly, HMDMs express markedly higher levels of CYP27A1 than THP-1 macrophages, and this difference was reflected in both protein levels and enzyme activities between the two cell types. In conclusion, stimulation of CYP27A1 by PPARγ may represent a key previously unrecognized mechanism by which PPARγ protects against atherosclerosis.

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The Molecular Mechanisms Underlying Prostaglandin D2-Induced Neuritogenesis in Motor Neuron-Like NSC-34 Cells

Cells ◽

10.3390/cells9040934 ◽

2020 ◽

Vol 9 (4) ◽

pp. 934 ◽

Cited By ~ 1

Author(s):

Hiroshi Nango ◽

Yasuhiro Kosuge ◽

Nana Yoshimura ◽

Hiroko Miyagishi ◽

Takanori Kanazawa ◽

...

Keyword(s):

Motor Neuron ◽

Neurite Outgrowth ◽

Motor Neurons ◽

Molecular Mechanisms ◽

Enzyme Linked Immunosorbent Assay ◽

Prostaglandin D2 ◽

Peroxisome Proliferator ◽

Neuron Development ◽

Peroxisome Proliferator Activated Receptor ◽

Lipid Compounds

Prostaglandins are a group of physiologically active lipid compounds derived from arachidonic acid. Our previous study has found that prostaglandin E2 promotes neurite outgrowth in NSC-34 cells, which are a model for motor neuron development. However, the effects of other prostaglandins on neuronal differentiation are poorly understood. The present study investigated the effect of prostaglandin D2 (PGD2) on neuritogenesis in NSC-34 cells. Exposure to PGD2 resulted in increased percentages of neurite-bearing cells and neurite length. Although D-prostanoid receptor (DP) 1 and DP2 were dominantly expressed in the cells, BW245C (a DP1 agonist) and 15(R)-15-methyl PGD2 (a DP2 agonist) had no effect on neurite outgrowth. Enzyme-linked immunosorbent assay demonstrated that PGD2 was converted to 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) under cell-free conditions. Exogenously applied 15d-PGJ2 mimicked the effect of PGD2 on neurite outgrowth. GW9662, a peroxisome proliferator-activated receptor–gamma (PPARγ) antagonist, suppressed PGD2-induced neurite outgrowth. Moreover, PGD2 and 15d-PGJ2 increased the protein expression of Islet-1 (the earliest marker of developing motor neurons), and these increases were suppressed by co-treatment with GW9662. These results suggest that PGD2 induces neuritogenesis in NSC-34 cells and that PGD2-induced neurite outgrowth was mediated by the activation of PPARγ through the metabolite 15d-PGJ2.

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Comparative toxicity of fatty acids on a macrophage cell line (J774)

Clinical Science ◽

10.1042/cs20060064 ◽

2006 ◽

Vol 111 (5) ◽

pp. 307-317 ◽

Cited By ~ 67

Author(s):

Thais Martins de Lima ◽

Maria Fernanda Cury-Boaventura ◽

Gisele Giannocco ◽

Maria Tereza Nunes ◽

Rui Curi

Keyword(s):

Fatty Acids ◽

Cell Death ◽

Cell Line ◽

Lipid Accumulation ◽

Membrane Integrity ◽

Peroxisome Proliferator ◽

Macrophage Cell Line ◽

Macrophage Cell ◽

Peroxisome Proliferator Activated Receptor ◽

High Concentrations

In the present study, the cytotoxicity of palmitic, stearic, oleic, linoleic, arachidonic, docosahexaenoic and eicosapentaenoic acids on a macrophage cell line (J774) was investigated. The induction of toxicity was investigated by changes in cell size, granularity, membrane integrity, DNA fragmentation and phosphatidylserine externalization by using flow cytometry. Fluorescence microscopy was used to determine the type of cell death (Acridine Orange/ethidium bromide assay). The possible mechanisms involved were examined by measuring mitochondrial depolarization, lipid accumulation and PPARγ (peroxisome-proliferator-activated receptor γ) activation. The results demonstrate that fatty acids induce apoptosis and necrosis of J774 cells. At high concentrations, fatty acids cause macrophage death mainly by necrosis. The cytotoxicity of the fatty acids was not strictly related to the number of double bonds in the molecules: palmitic acid>docosahexaenoic acid>stearic acid=eicosapentaenoic acid=arachidonic acid>oleic acid>linoleic acid. The induction of cell death did not involve PPARγ activation. The mechanisms of fatty acids to induce cell death involved changes in mitochondrial transmembrane potential and intracellular neutral lipid accumulation. Fatty acids poorly incorporated into triacylglycerol had the highest toxicity.

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