9-deoxy-delta-9-prostaglandin-d2 and Inflammation

Prostaglandins (PGs) are produced via cyclooxygenases, which are enzymes that play a major role in neuroinflammation. Epidemiological studies show that chronic treatment with low levels of cyclooxygenase inhibitors (nonsteroidal anti-inflammatory drugs (NSAIDs)) lowers the risk for Alzheimer's disease (AD) and Parkinson's disease (PD) by as much as 50%. Unfortunately, inhibiting cyclooxygenases with NSAIDs blocks the synthesis of downstream neuroprotective and neurotoxic PGs, thus producing adverse side effects. We focus on prostaglandin J2 (PGJ2) because it is highly neurotoxic compared to PGA1, D2, and E2. Unlike other PGs, PGJ2 and its metabolites have a cyclopentenone ring with reactive α,β-unsaturated carbonyl groups that form covalent Michael adducts with key cysteines in proteins and GSH. Cysteine-binding electrophiles such as PGJ2 are considered to play an important role in determining whether neurons will live or die. We discuss in vitro and in vivo studies showing that PGJ2 induces pathological processes relevant to neurodegenerative disorders such as AD and PD. Further, we discuss our work showing that increasing intracellular cAMP with the lipophilic peptide PACAP27 counteracts some of the PGJ2-induced detrimental effects. New therapeutic strategies that neutralize the effects of specific neurotoxic PGs downstream from cyclooxygenases could have a significant impact on the treatment of chronic neurodegenerative disorders with fewer adverse side effects.

Topics: Alzheimer Disease; Animals; Disease Models, Animal; Humans; Inflammation; Lipopolysaccharides; Neurodegenerative Diseases; Neurons; Parkinson Disease; Prostaglandin D2; Prostaglandins; Protein Binding; Protein Processing, Post-Translational; Receptors, Prostaglandin; Signal Transduction

Prostaglandin D(2) (PGD(2)) is produced by a variety of immune and non-hematopoietic cells and appears to function in both an inflammatory and homeostatic capacity. Two genetically distinct PGD(2)-synthesizing enzymes have been identified to date, including hematopoietic- and lipocalin-type PGD synthases (H-PGDS and L-PGDS, respectively). Though the inter-species expression profiles of these two enzymes vary widely, H-PGDS is generally localized to the cytosolic aspect of immune and inflammatory cells, whereas L-PGDS is more resigned to tissue-based expression. PGD(2) activity is principally mediated through two unique G protein-coupled receptors (GPCR), designated DP(1) and DP(2). These receptors exhibit overlapping binding profiles, yet their respective agonists elicit generally distinctive responses. Additional to DP receptors, the PGD(2) metabolite 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) binds the nuclear peroxisome proliferator-activated receptor gamma (PPARgamma) and has the facility to initiate a variety of anti-inflammatory phenotypes either through or independent of PPARgamma association. This review highlights the collective relevance of PGD(2) and its respective synthases, receptors, and metabolites in immunopathologic responses.

Topics: Animals; Inflammation; Intramolecular Oxidoreductases; Isoprostanes; Lipocalins; Mice; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases; Receptors, Prostaglandin

PPARgamma has been recently described as being a gene of susceptibility for Intestinal Bowel Diseases (IBD) as NOD2/CARD15 gene. IBD are pathologies due to an abnormal immune response, in genetically predisposed patients, to the bacteria of the intestinal flora. PPARgamma, known for its significant role in adipogenesis, is strongly expressed by the epithelial cells of the colon mucosa. PPARgamma is implicated in the regulation of inflammation. Indeed, agonists of this nuclear receptor decrease strongly the intensity of inflammation during experimental colitis induced by chemical agents. A deficit of PPARgamma in patients with ulcerative colitis has been highlighted, that could in part explain the acute inflammation. In addition, bacteria, including those of the commensal flora, are able to regulate PPARgamma. Toll Like Receptor-4 (TLR-4), responsible for the recognition of bacterial motif as lipopolysaccharide (LPS), is implicated in PPARgamma regulation and its anti-inflammatory properties. All these arguments make of PPARgamma a very interesting therapeutic target for the treatment of IBD.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Bacterial Physiological Phenomena; Colitis, Ulcerative; Crohn Disease; Eicosanoids; Fatty Acids, Omega-3; Homeostasis; Humans; Inflammation; Inflammatory Bowel Diseases; Insulin Resistance; Intestinal Mucosa; Ligands; Lipid Metabolism; Mice; PPAR gamma; Prostaglandin D2; Thiazolidinediones; Toll-Like Receptor 4

Topics: Cyclooxygenase 2; Humans; Inflammation; Inflammation Mediators; Ligands; Membrane Proteins; NF-kappa B; Nitric Oxide Synthase Type II; PPAR gamma; Prostaglandin D2; Signal Transduction; Thioredoxins

Prostaglandins (PGs) of the J2 family including PGJ2, delta12-PGJ2, and 15-deoxy-delta12,14-PGJ2 (15d-PGJ2) are naturally occurring metabolites of PGD2. Among them, 15d-PGJ2 is a powerful ligand for the peroxisome proliferator-activated receptor-gamma (PPARgamma). 15d-PGJ2 and synthetic PPARgamma ligands have been reported to exert several effects on vascular cells, such as anti-proliferative, differentiation-inducing, anti-apoptotic, and anti-inflammatory effects, most of which seem to be atheroprotective, although PPARgamma-independent mechanisms may be involved. Vascular endothelial cells, intimal smooth muscle cells, and cardiomyocytes express lipocalin-type PGD synthase (L-PGDS) in vivo, which catalyzes the isomeric conversion of PGH2 to PGD2. L-PGDS expression in endothelial cells is stimulated by laminar fluid shear stress. PGD2 and 15d-PGJ2 are detected in the culture medium of endothelial cells exposed to shear stress. Serum and urinary levels of L-PGDS increase in diseases with vascular injuries, such as hypertension and diabetes. Based on these findings, we hypothesize that PGs of the J2 series are physiological substances produced in the vascular wall to protect vascular cells from injurious stimuli and to repress inflammatory reactions. If this hypothesis is correct, PGJ2 family members or other similar substances may provide novel preventive and therapeutic strategies for the treatment of vascular diseases.

Topics: Animals; Apoptosis; Cardiovascular Diseases; Cardiovascular System; Humans; Inflammation; Prostaglandin D2

The peroxisome proliferator-activated receptor gamma is a nuclear hormone receptor playing a crucial role in adipogenesis and insulin sensitization. Prostaglandin J2 derivatives and the antidiabetic thiazolidinediones are its respective natural and synthetic ligands. The RXR/PPAR gamma heterodimer has also been reported to have important immunomodulatory activities and its pleiotropic functions suggest wide-ranging medical implications.

Topics: Adipose Tissue; Animals; Arteriosclerosis; Gene Expression; Humans; Inflammation; Insulin; Ligands; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Thiazoles; Thiazolidinediones; Transcription Factors

Topics: Animals; Antineoplastic Agents; Antiviral Agents; Carrier Proteins; Cell Division; Fatty Acid-Binding Protein 7; Fatty Acid-Binding Proteins; Hot Temperature; Humans; Inflammation; Molecular Structure; Neoplasm Proteins; Osteogenesis; Prostaglandin D2; Tumor Suppressor Proteins

Female fertility depends greatly on the capacity of the uterus to recognize and eliminate microbial infections, a major reason of inflammation in the endometrium in many species. This study aimed to determine the in vitro effect of peroxisome proliferator-activated receptor gamma (PPARγ) ligands on the transcriptome genes expression and alternative splicing in the porcine endometrium in the mid-luteal phase of the estrous cycle during LPS-stimulated inflammation using RNA-seq technology. The endometrial slices were incubated in vitro in the presence of LPS and PPARγ agonists-PGJ2 or pioglitazone and antagonist-T0070907. We identified 222, 3, 4, and 62 differentially expressed genes after LPS, PGJ2, pioglitazone, or T0070907 treatment, respectively. In addition, we detected differentially alternative spliced events: after treatment with LPS-78, PGJ2-60, pioglitazone-52, or T0070907-134. These results should become a basis for further studies explaining the mechanism of PPARγ action in the reproductive system in pigs.

Topics: Alternative Splicing; Animals; Benzamides; Endometrium; Female; Gene Expression Profiling; Inflammation; Lipopolysaccharides; Pioglitazone; PPAR gamma; Prostaglandin D2; Pyridines; Swine

Regulation of the amyloid precursor protein (APP) processing by α- and β-secretases is of special interest to Alzheimer's disease (AD), as these proteases prevent or mediate amyloid beta formation, respectively. Neuroinflammation is also implicated in AD. Our data demonstrate that the endogenous mediator of inflammation prostaglandin J2 (PGJ2) promotes full-length APP (FL-APP) processing by α- and β-secretases. The decrease in FL-APP was independent of proteasomal, lysosomal, calpain, caspase, and γ-secretase activities. Moreover, PGJ2-treatment promoted cleavage of secreted APP, specifically sAPPα and sAPPβ, generated by α and β-secretase, respectively. Notably, PGJ2-treatment induced caspase-dependent cleavage of sAPPβ. Mechanistically, PGJ2-treatment selectively diminished mature (O- and N-glycosylated) but not immature (N-glycosylated only) FL-APP. PGJ2-treatment also increased the overall levels of protein O-GlcNAcylation, which occurs within the nucleocytoplasmic compartment. It is known that APP undergoes O-GlcNAcylation and that the latter protects proteins from proteasomal degradation. Our results suggest that by increasing protein O-GlcNAcylation levels, PGJ2 renders mature APP less prone to proteasomal degradation, thus shunting APP toward processing by α- and β-secretases.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Caspases; Cells, Cultured; Cytoplasm; Female; Glycosylation; Humans; Inflammation; Male; Prostaglandin D2; Proteasome Endopeptidase Complex; Proteolysis; Rats, Sprague-Dawley; Tumor Cells, Cultured

The insulin sensitizing thiazolidinedione drugs, rosiglitazone and pioglitazone are specific peroxisome proliferator-activated receptor-gamma agonists and reduce pro-inflammatory responses in patients with type 2 diabetes and coronary artery disease, and may be beneficial in sepsis. Sepsis was induced in 8-10-wk-old C57BL/6 mice by cecal ligation and puncture (CLP) with a 22 -g double puncture technique. Mice received an i.p. injection of vehicle (DMSO:PBS) or pioglitazone (20 mg/kg) at 1 h and 6 h after CLP, and were sacrificed at various time points. In sepsis, vehicle-treated mice had hypoglycemia, increased lung injury and increased lung neutrophil infiltration. Pro-inflammatory plasma cytokines were increased, but the plasma adipokine, adiponectin, was decreased in vehicle-treated septic mice. This corresponded with inhibitor κB (IκBα) protein degradation and an increase in NF-κB activity in lung. Pioglitazone treatment improved plasma Glc and adiponectin levels, and decreased pro-inflammatory cytokines. Lung IκBα protein expression increased and corresponded with a decrease in NF-κB activity in the lung from pioglitazone-treated mice. Pioglitazone reduces the inflammatory response in polymicrobial sepsis in part through inhibition of NF-κB and may be a novel therapy in sepsis.

Topics: Adipokines; Animals; Cytokines; Hypoglycemia; Hypoglycemic Agents; I-kappa B Proteins; Inflammation; Lung; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Pioglitazone; PPAR gamma; Prostaglandin D2; Sepsis; Thiazolidinediones

Neutrophils and their chemoattractants, the CXC-ELR chemokines keratinocyte cytokine (KC) and macrophage inflammatory protein-2 (MIP-2), play a critical role in pancreatitis. While acute pancreatitis is initiated in acinar cells, it is unclear if these are a source of CXC-ELR chemokines. KC and MIP-2 have NF-κB, activator protein-1 (AP-1) sites in their promoter regions. However, previous studies have shown increased basal and reduced caerulein-induced AP-1 activation in harvested pancreatic tissue in vitro, which limits interpreting the caerulein-induced response. Moreover, recent studies suggest that NF-κB silencing in acinar cells alone may not be sufficient to reduce inflammation in acute pancreatitis. Thus the aim of this study was to determine whether acinar cells are a source of KC and MIP-2 and to understand their transcriptional regulation. Primary overnight-cultured murine pancreatic acini were used after confirming their ability to replicate physiological and pathological acinar cell responses. Upstream signaling resulting in KC, MIP-2 upregulation was studied along with activation of the transcription factors NF-κB and AP-1. Cultured acini replicated critical responses to physiological and pathological caerulein concentrations. KC and MIP-2 mRNA levels increased in response to supramaximal but not to physiological caerulein doses. This upregulation was calcium and protein kinase C (PKC), but not cAMP, dependent. NF-κB inhibition completely prevented upregulation of KC but not MIP-2. Complete suppression of MIP-2 upregulation required dual inhibition of NF-κB and AP-1. Acinar cells are a likely source of KC and MIP-2 upregulation during pancreatitis. This upregulation is dependent on calcium and PKC. MIP-2 upregulation requires both NF-κB and AP-1 in these cells. Thus dual inhibition of NF-κB and AP-1 may be a more successful strategy to reduce inflammation in pancreatitis than targeting NF-κB alone.

Topics: Animals; Calcium; Ceruletide; Chemokine CXCL1; Chemokine CXCL2; Inflammation; Mice; NF-kappa B; Pancreas; Prostaglandin D2; Protein Kinase C; RNA, Messenger; Tissue Culture Techniques; Transcription Factor AP-1; Transcription, Genetic; Up-Regulation

Neutrophils (polymorphonuclear leukocytes [PMNs]) are critical to the immune response, including clearance of infectious pathogens. Sepsis is associated with impaired PMN function, including chemotaxis. PMNs express peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a ligand-activated nuclear transcription factor involved in immune and inflammatory regulation. The role of PPAR-gamma in PMN responses, however, is not well characterized. We report that freshly isolated human PMNs constitutively express PPAR-gamma, which is up-regulated by the sepsis-induced cytokines TNF-alpha and IL-4. PMN chemotactic responses to formylmethionyl-leucyl-phenylalanine (fMLP) and IL-8 were dose-dependently inhibited by treatment with the PPAR-gamma ligands troglitazone and 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) and by transfection of PMN-like HL-60 cells with a constitutively active PPAR-gamma construct. Inhibition of chemotaxis by PPAR-gamma ligands correlated with decreases in extracellular signal-regulated kinase-1 and -2 activation, actin polymerization, and adherence to a fibrinogen substrate. Furthermore, PMN expression of PPAR-gamma was increased in sepsis patients and mice with either of 2 models of sepsis. Finally, treatment with the PPAR-gamma antagonist GW9662 significantly reversed the inhibition of PMN chemotaxis and increased peritoneal PMN recruitment in murine sepsis. This study indicates that PPAR-gamma activation is involved in PMN chemotactic responses in vitro and may play a role in the migration of these cells in vivo.

Topics: Actins; Anilides; Animals; Antineoplastic Agents; Cell Adhesion; Chemotaxis; Chromans; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Fibrinogen; HL-60 Cells; Humans; Inflammation; Interleukin-4; Interleukin-8; Male; Mice; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; N-Formylmethionine Leucyl-Phenylalanine; PPAR gamma; Prostaglandin D2; Sepsis; Thiazolidinediones; Troglitazone; Tumor Necrosis Factor-alpha; Up-Regulation

Many neurodegenerative disorders are characterized by two pathological hallmarks: progressive loss of neurons and occurrence of inclusion bodies containing ubiquitinated proteins. Inflammation may be critical to neurodegeneration associated with ubiquitin-protein aggregates. We previously showed that prostaglandin J2 (PGJ2), one of the endogenous products of inflammation, induces neuronal death and the accumulation of ubiquitinated proteins into distinct aggregates. We now report that temporal microarray analysis of human neuroblastoma SK-N-SH revealed that PGJ2 triggered a "repair" response including increased expression of heat shock, protein folding, stress response, detoxification and cysteine metabolism genes. PGJ2 also decreased expression of cell growth/maintenance genes and increased expression of apoptotic genes. Over time pro-death responses prevailed over pro-survival responses, leading to cellular demise. Furthermore, PGJ2 increased the expression of proteasome and other ubiquitin-proteasome pathway genes. This increase failed to overcome PGJ2 inhibition of 26 S proteasome activity. Ubiquitinated proteins are degraded by the 26 S proteasome, shown here to be the most active proteasomal form in SK-N-SH cells. We demonstrate that PGJ2 impairs 26 S proteasome assembly, which is an ATP-dependent process. PGJ2 perturbs mitochondrial function, which could be critical to the observed 26 S proteasome disassembly, suggesting a cross-talk between mitochondrial and proteasomal impairment. In conclusion neurotoxic products of inflammation, such as PGJ2, may play a role in neurodegenerative disorders associated with the aggregation of ubiquitinated proteins by impairing 26 S proteasome activity and inducing a chain of events that culminates in neuronal cell death. Temporal characterization of these events is relevant to understanding the underlying mechanisms and to identifying potential early biomarkers.

Topics: Biomarkers; Cell Line, Tumor; Cell Survival; DNA Repair; Gene Expression Regulation, Neoplastic; Humans; Inflammation; Neuroblastoma; Neurons; Oligonucleotide Array Sequence Analysis; Prostaglandin D2; Proteasome Endopeptidase Complex; Reverse Transcriptase Polymerase Chain Reaction

Many neurodegenerative disorders, such as Parkinson disease, exhibit inclusion bodies containing ubiquitinated proteins. The mechanisms implicated in this aberrant protein deposition remain elusive. In these disorders signs of inflammation are also apparent in the affected central nervous system areas. We show that prostaglandin J2 (PGJ2), an endogenous product of inflammation, disrupts the cytoskeleton in neuronal cells. Furthermore, PGJ2 perturbed microtubule polymerization in vitro and decreased the number of free sulfhydryl groups on tubulin cysteines. A direct effect of PGJ2 on actin was not apparent, although actin filaments were altered in cells treated with PGJ2. This cyclopentenone prostaglandin triggered endoplasmic reticulum (ER) collapse and the redistribution of ER proteins, such as calnexin and catechol-O-methyltransferase, into a large centrosomal aggregate containing ubiquitinated proteins and alpha-synuclein. The PGJ2-dependent cytoskeletal rearrangement paralleled the development of the large centrosomal aggregate. Both of these events were replicated by treating cells with colchicine, which disrupts the microtubule/ER network, but not with brefeldin A, which impairs ER/Golgi transport. PGJ2 also perturbed 26 S proteasome assembly and activity, which preceded the accumulation of ubiquitinated proteins as detergent/salt-insoluble aggregates. Our data support a mechanism by which, upon PGJ2 treatment, cytoskeleton/ER collapse coincides with the relocation of ER proteins, other potentially neighboring proteins, and ubiquitinated proteins into centrosomal aggregates. Development of these large perinuclear aggregates is associated with disruption of the microtubule/ER network. This aberrant protein deposition, triggered by a product of inflammation, may be common to other compounds that disrupt microtubules and induce protein aggregation, such as MPP+ and rotenone, found to be associated with neurodegeneration.

Topics: Actins; alpha-Synuclein; Cell Line, Tumor; Centrosome; Cyclopentanes; Cytoskeleton; Endoplasmic Reticulum; Humans; Inflammation; Kinetics; Microtubules; Neurodegenerative Diseases; Prostaglandin D2; Proteasome Endopeptidase Complex; Protein Binding; Ubiquitin

To investigate molecular mechanisms linking inflammation with neurodegeneration, we treated neuronal cultures with prostaglandins (PGs), which are mediators of inflammation. PGA1, D2, J2, and Delta12-PGJ2, but not PGE2, reduced the viability and raised the levels of ubiquitinated proteins in the neuronal cells. PGJ2 and its metabolite, Delta12-PGJ2, were the most potent of the four neurotoxic PGs tested in inducing both effects. To address the mechanism by which these agents lead to the accumulation of ubiquitinated proteins, we tested their effects on neuronal ubiquitin hydrolases UCH-L1 and UCH-L3 as well as on proteasome activity. Notably, Delta12-PGJ2 inhibited the activities of UCH-L1 (K(i) approximately 3.5 microM) and UCH-L3 (K(i) approximately 8.1 microM) without affecting proteasome activity. Intracellular aggregates containing ubiquitinated proteins were detected in Delta12-PGJ2-treated cells, indicating that these aggregates can form independently of proteasome inhibition. In conclusion, impairment of ubiquitin hydrolase activity, such as triggered by Delta12-PGJ2, may be an important contributor to neurodegeneration associated with accumulation of ubiquitinated proteins and inflammation.

Topics: Animals; Antineoplastic Agents; Cells, Cultured; Cysteine Endopeptidases; Dinoprostone; Enzyme Inhibitors; Inflammation; Mice; Molecular Structure; Multienzyme Complexes; Neurons; Prostaglandin D2; Prostaglandins A; Proteasome Endopeptidase Complex; Rats; Ubiquitin; Ubiquitin Thiolesterase

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists are now emerging as therapeutic drugs for various inflammatory diseases. However, their molecular mechanism of action remains to be elucidated. Here we report a novel mechanism that underlies the PPAR-gamma agonist-mediated suppression of brain inflammation. We show that 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)) and rosiglitazone reduce the phosphorylation of STAT1 and STAT3 as well as Janus kinase 1 (JAK1) and JAK2 in activated astrocytes and microglia. The PPAR-gamma agonist-mediated reduction in phosphorylation leads to the suppression of JAK-STAT-dependent inflammatory responses. The effects of 15d-PGJ(2) and rosiglitazone are not mediated by activation of PPAR-gamma. 15d-PGJ(2) and rosiglitazone rapidly induce the transcription of suppressor of cytokine signaling (SOCS) 1 and 3, which in turn inhibit JAK activity in activated glial cells. In addition, Src homology 2 domain-containing protein phosphatase 2 (SHP2), another negative regulator of JAK activity, is also involved in their anti-inflammatory action. Our data suggest that 15d-PGJ(2) and rosiglitazone suppress the initiation of JAK-STAT inflammatory signaling independently of PPAR-gamma, thus attenuating brain inflammation.

Topics: Animals; Anti-Inflammatory Agents; Astrocytes; Carrier Proteins; DNA-Binding Proteins; Gene Expression Regulation; Inflammation; Janus Kinase 1; Janus Kinase 2; Neuroglia; Phosphorylation; Prostaglandin D2; Protein Biosynthesis; Protein-Tyrosine Kinases; Proteins; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Repressor Proteins; Rosiglitazone; Signal Transduction; STAT1 Transcription Factor; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 1 Protein; Suppressor of Cytokine Signaling 3 Protein; Suppressor of Cytokine Signaling Proteins; Thiazoles; Thiazolidinediones; Trans-Activators; Transcription Factors

Monocytes/macrophages (Mphi) play a pivotal role in the persistence of chronic inflammation and local tissue destruction in diseases such as rheumatoid arthritis and atherosclerosis. The production by Mphi of cytokines, chemokines, metalloproteinases and their inhibitors is an essential component in this process, which is tightly regulated by multiple factors. The peroxisome proliferator-activated receptors (PPARs) were shown to be involved in modulating inflammation. PPARgamma is activated by a wide variety of ligands such as fatty acids, the anti-diabetic thiazolidinediones (TZDs), and also by certain prostaglandins of which 15-deoxy-Delta(12,14)-PGJ2 (PGJ2). High concentrations of PPARgamma ligands were shown to have anti-inflammatory activities by inhibiting the secretion of interleukin-1 (IL-1), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNFalpha) by stimulated monocytes. The aim of this study was to determine whether PGJ2 and TZDs would also exert an immunomodulatory action through the up-regulation of anti-inflammatory cytokines such as the IL-1 receptor antagonist (IL-1Ra). THP-1 monocytic cells were stimulated with PMA, thereby enhancing the secretion of IL-1, IL-6, TNFalpha, IL-1Ra and metalloproteinases. Addition of PGJ2 had an inhibitory effect on IL-1, IL-6 and TNFalpha secretion, while increasing IL-1Ra production. In contrast, the bona fide PPARgamma ligands (TZDs; rosiglitazone, pioglitazone and troglitazone) barely inhibited proinflammatory cytokines, but strongly enhanced the production of IL-1Ra from PMA-stimulated THP-1 cells. Unstimulated cells did not respond to TZDs in terms of IL-1Ra production, suggesting that in order to be effective, PPAR ligands depend on PMA signalling. Basal levels of PPARgamma are barely detectable in unstimulated THP-1 cells, while stimulation with PMA up-regulates its expression, suggesting that higher levels of PPARgamma expression are necessary for receptor ligand effects to occur. In conclusion, we demonstrate for the first time that TZDs may exert an anti-inflammatory activity by inducing the production of the IL-1Ra.

Topics: Antineoplastic Agents; Cell Differentiation; Cell Line; Cell Separation; Enzyme Inhibitors; Fibrinolytic Agents; Flow Cytometry; Humans; Inflammation; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Interleukin-6; Ligands; Monocytes; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Rosiglitazone; Sialoglycoproteins; Thiazoles; Thiazolidinediones; Time Factors; Transcription Factors; Tretinoin; Tumor Necrosis Factor-alpha; Up-Regulation; Vitamin D

Topics: Animals; CCAAT-Enhancer-Binding Protein-delta; CCAAT-Enhancer-Binding Proteins; Cells, Cultured; Chromans; DNA-Binding Proteins; Gene Expression Regulation; Inflammation; Luciferases; Muscle, Smooth, Vascular; NF-kappa B; Phosphorylation; Prostaglandin D2; Protein Binding; Rats; Receptors, Cytoplasmic and Nuclear; Recombinant Fusion Proteins; STAT3 Transcription Factor; Thiazoles; Thiazolidinediones; Trans-Activators; Transcription Factors; Troglitazone

CCAAT/enhancer-binding proteins (C/EBPs) upregulate transcription of various inflammatory cytokines and acute phase proteins, such as interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, and cyclooxygenase-2. Recent studies have demonstrated that peroxisome proliferator-activated receptor (PPAR)-gamma is present in atherosclerotic lesions, and negatively regulates expression of these genes. Interestingly, PPAR-gamma gene promoter has tandem repeats of C/EBP-binding motif, and C/EBP-delta plays a pivotal role in transactivation of PPAR-gamma gene. It has been well known that the interaction between C/EBPs and PPAR-gamma plays a central role in maintaining adipocyte differentiation and glucometabolism; however, the relationship between PPAR-gamma and C/EBPs in the vessel wall remains unclear. In the present study, we showed that a high level of C/EBP-delta expression induced by inflammation positively regulated transcription and protein expression of PPAR-gamma in vascular smooth muscle cells (VSMCs). On the other hand, PPAR-gamma ligands troglitazone, pioglitazone, and 15-deoxy-Delta(12,14)-prostaglandin J(2) inhibited IL-1beta-induced IL-6 expression at a transcriptional revel in VSMCs. Functional promoter analysis revealed that PPAR-gamma ligands inhibited IL-1beta-induced transactivation of IL-6 gene via suppression of not only nuclear factor-kappaB but also C/EBP-DNA binding. Moreover, PPAR-gamma ligands suppressed protein expression and transcription of C/EBP-delta through dephosphorylation of signal transducer and activator of transcription 3. These findings strongly suggest that C/EBP-delta is negatively autoregulated via transactivation of PPAR-gamma. This feedback mechanism probably downregulates transcription of inflammatory cytokines and acute phase proteins, and modulates inflammatory responses in the early process of atherosclerosis.

Topics: Animals; Carotid Arteries; CCAAT-Enhancer-Binding Protein-delta; CCAAT-Enhancer-Binding Proteins; Cells, Cultured; Chromans; DNA-Binding Proteins; Gene Expression Regulation; Inflammation; Interleukin-6; Luciferases; Male; Muscle, Smooth, Vascular; NF-kappa B; Phosphorylation; Prostaglandin D2; Protein Binding; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Recombinant Fusion Proteins; STAT3 Transcription Factor; Thiazoles; Thiazolidinediones; Trans-Activators; Transcription Factors; Transcription, Genetic; Troglitazone

Prostaglandin D2 (PGD2) exerts a variety of biologic actions in the eye; these include ocular hypotension and inflammatory effects on the conjunctiva. The profile of activity of PGD2 in ocular tissues was compared to that of BW 245C, a selective agonist for the PGD2-sensitive (DP) receptor, and to that of the biologically active metabolites of PGD2, 9 alpha,11 beta-prostaglandin F2 (9 alpha,11 beta-PGF2) and prostaglandin J2 (PGJ2). PGD2 produced a dose-dependent decrease in intraocular pressure and in the conjunctiva it caused increased conjunctival microvascular permeability, eosinophil infiltration and goblet cell depletion. Although BW 245C was equipotent to PGD2 as an ocular hypotensive agent, it did not cause pathological effects in the conjunctiva. Thus, the ocular hypotensive effect of PGD2 may be separated from inflammatory effects on the conjunctiva by employing a selective DP-receptor agonist such as BW 245C. 9 alpha,11 beta-PGF2 was a weak ocular hypotensive and did not cause conjunctival inflammation. PGJ2 produced no significant effect on intraocular pressure. PGJ2 did not elicit a microvascular permeability response in the conjunctiva, but was inflammatory in other respects and caused eosinophil infiltration and goblet cell depletion similar to PGD2. Thus, both the ocular hypotensive actions and the conjunctival pathology of PGD2 may be replicated individually by employing PGD2 analogues and metabolites.

Topics: Animals; Aqueous Humor; Capillary Permeability; Chemotaxis, Leukocyte; Conjunctiva; Dinoprost; Eosinophils; Evans Blue; Eye; Female; Guinea Pigs; Hydantoins; Inflammation; Intraocular Pressure; Male; Prostaglandin D2; Rabbits