Inhibition of Carrageenan-Induced Cutaneous Inflammation by PPAR Agonists Is Dependent on Hepatocyte-Specific Retinoid X ReceptorAlpha

Symmetrical bis-tertiary amines as novel CXCR4 inhibitors

CXCR4 inhibitors are promising agents for the treatment of cancer metastasis and inflammation. A series of novel tertiary amine derivatives targeting CXCR4 were designed, synthesized, and evaluated. The central benzene ring linker and side chains were modified and optimized to study the structure-activity relationship. Seven compounds displayed much more potent activity than the reference drug, AMD3100, in both the binding affinity assay and the blocking of Matrigel invasion functional assay. These compounds exhibited effective concentration ranging from 1 to 100 nM in the binding affinity assay and inhibited invasion from 65.3% to 100% compared to AMD3100 at 100 nM. Compound IIn showed a 50% suppressive effect against carrageenan-induced paw inflammation in a mouse model, which was as effective as the peptidic antagonist, TN14003 (48%). These data demonstrate that symmetrical bis-tertiary amines are unique CXCR4 inhibitors with high potency.

Unique physicochemical properties of perfluorinated compounds and their bioconcentration in common carp Cyprinus carpio L

Carp (Cyprinus carpio L.) was exposed to perfluorinated compounds (PFCs)-perfluoroalkyl carboxylic acids (number of carbon atoms, C = 8, 11, 12, 14, 16, and 18) and perfluorooctane sulfonate (PFOS)-in bioconcentration tests to compare the bioconcentration factors (BCFs) and physicochemical properties of each specific compound. Despite having the same number of carbon atoms (C = 8), the BCFs of perfulorooctanoic acid (PFOA) and PFOS differed by more than two orders of magnitude (PFOA BCF = < 5.1 to 9.4; PFOS BCF = 720 to 1300). The highest BCFs were obtained from perfluorododecanoic acid (BCF = 10,000 to 16,000) and perfluorotetradecanoic acid (BCF = 16,000 to 17,000). The longest observed depuration half-lives were for perfluorohexadecanoic acid (48 to 54 days) and PFOS (45 to 52 days). The concentrations of PFCs were highest in the viscera, followed by the head, integument, and remaining parts of the test fish. PFCs concentrations in the integument, which was in direct contact with the test substances, were relatively greater than that of other lipophilic substance (hexachlorobenzene). It is likely that Clog P would be a better parameter than log K (ow) for the prediction of BCFs for PFCs. Threshold values for PFCs bioaccumulation potential (molecular weight = 700, maximum diameter = 2 nm) seemed to deviate from those generally reported because of the specific steric bulk effect of molecule size.

Involvement of the Retinoid X Receptor Ligand in the Anti-Inflammatory Effect Induced by Peroxisome Proliferator-Activated Receptor γ Agonist In Vivo

Peroxisome proliferator-activated receptor γ (PPARγ) forms a heterodimeric DNA-binding complex with retinoid X receptors (RXRs). It has been reported that the effect of the PPAR agonist is reduced in hepatocyte RXR-deficient mice. Therefore, it is suggested that the endogenous RXR ligand is involved in the PPARγ agonist-induced anti-inflammatory effect. However, the participation of the RXR ligand in the PPARγ-induced anti-inflammatory effect is unknown. Here, we investigated the influence of RXR antagonist on the anti-inflammatory effect of PPARγ agonist pioglitazone in carrageenan test. In addition, we also examined the influence of PPAR antagonist on the anti-inflammatory effect induced by RXR agonist NEt-3IP. The RXR antagonist suppressed the antiedema effect of PPARγ agonist. In addition, the anti-inflammatory effect of RXR agonist was suppressed by PPARγ antagonist. PPARγ agonist-induced anti-inflammatory effects were reversed by the RXR antagonist. Thus, we showed that the endogenous RXR ligand might contribute to the PPARγ agonist-induced anti-inflammatory effect.

PPARs are a unique set of fatty acid regulated transcription factors controlling both lipid metabolism and inflammation

Cells are constantly exposed to a large variety of lipids. Traditionally, these molecules were thought to serve as simple energy storing molecules. More recently it has been realized that they can also initiate and regulate signaling events that will decisively influence development, cellular differentiation, metabolism and related functions through the regulation of gene expression. Multicellular organisms dedicate a large family of nuclear receptors to these tasks. These proteins combine the defining features of both transcription factors and receptor molecules, and therefore have the unique ability of being able to bind lipid signaling molecules and transduce the appropriate signals derived from lipid environment to the level of gene expression. Intriguingly, the members of a subfamily of the nuclear receptors, the peroxisome proliferator-activated receptors (PPARs) are able to sense and interpret fatty acid signals derived from dietary lipids, pathogenic lipoproteins or essential fatty acid metabolites. Not surprisingly, Peroxisome proliferator-activated receptors were found to be key regulators of lipid and carbohydrate metabolism. Unexpectedly, later studies revealed that Peroxisome proliferator-activated receptors are also able to modulate inflammatory responses. Here we summarize our understanding on how these transcription factors/receptors connect lipid metabolism to inflammation and some of the novel regulatory mechanisms by which they contribute to homeostasis and certain pathological conditions. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.

Optical imaging of bacterial infection in living mice using deep-red fluorescent squaraine rotaxane probes

Two structurally related fluorescent imaging probes allow optical imaging of bacterial leg infection models in living athymic and immunocompetent mice. Structurally, the probes are comprised of a deep-red fluorescent squaraine rotaxane scaffold with two appended bis(zinc(II)-dicolylamine) (bis(Zn-DPA)) targeting ligands. The bis(Zn-DPA) ligands have high affinity for the anionic phospholipids and related biomolecules that reside within the bacterial envelope, and they are known to selectively target bacterial cells over the nearly uncharged membrane surfaces of healthy mammalian cells. Planar, whole-animal optical imaging studies showed that intravenous dosing of either probe (10 nmol) allowed imaging of localized infections of Gram-positive Staphylococcus aureus and Gram-negative Salmonella enterica serovar typhimurium. High selectivity for the infected target leg (T) over the contralateral nontarget leg (NT) was reflected by T/NT ratios up to six. The infection imaging signal was independent of mouse humoral immune status, and there was essentially no targeting at a site of sterile inflammation induced by injection of lambda-carrageenan. Furthermore, the fluorescent probe imaging signal colocalized with the bioluminescence signal from a genetically engineered strain of S. enterica serovar typhimurium. Although not highly sensitive (the localized infection must contain at least approximately 10(6) colony forming units for fluorescence visualization), the probes are remarkably selective for bacterial cells considering their low molecular weight (<1.5 kDa) and simple structural design. The more hydrophilic of the two probes produced a higher T/NT ratio in the early stages of the imaging experiment and washed out more rapidly from the blood clearance organs (liver, kidney). Therefore, it is best suited for longitudinal studies that require repeated dosing and imaging of the same animal. The results indicate that fluorescent probes based on squaraine rotaxanes should be broadly useful for in vivo animal imaging studies, and they further validate the ability of imaging probes with bis(Zn-DPA) ligands to selectively target bacterial infections in living animals.

Glucans from the Caripia montagnei mushroom present anti-inflammatory activity

Caripia montagnei is a basidiomycete species which contains polysaccharides with immunomodulatory properties. An extract of this mushroom underwent removal of the fat content by organic solvent and subsequently proteolysis. The aqueous phase obtained after proteolysis was precipitated with methanol yielding a fraction containing carbohydrates (98.7+/-3.3%) and protein (1.3+/-0.25%). Chemical analysis, infrared spectroscopy and nuclear magnetic resonance (NMR) showed that the carbohydrate fraction contained (63.3+/-4.1) of beta-glucans and proteins (2.2+/-0.3%). These glucans (50mg/kg of body weight) significantly reduced the inflammatory infiltrate produced by thioglycolate-induced peritonitis by 75.5+/-5.2%, when compared to Wy-14643 (60.3+/-6.1%), PFOA (37.8+/-2.8%) and clofibrate (52.2+/-3.2%), p<0.001, which are of the peroxisome proliferator-activated receptor (PPAR-alpha). L-NAME, a nitric oxide synthase inhibitor, reduced the plantar edema in Wistar rats by 91.4+/-1.3% (p<0.001). A significant reduction in nitric oxide (NO) levels was observed in the exudates when the glucans was used in comparison to carrageenan. The C. montagnei glucans did not present signs of inducing cytotoxicity. A decrease in IL-1ra, IL-10 and IFN-gamma in the peritonitis model was observed. Thus, the results suggest that glucans from the C. montagnei mushroom is an effective immunomodulator and may have potential for anti-inflammatory properties.

Nuclear receptors and inflammatory diseases

It is well known that the steroid hormone glucocorticoid and its nuclear receptor regulate the inflammatory process, a crucial component in the pathophysiological process related to human diseases that include atherosclerosis, obesity and type II diabetes, inflammatory bowel disease, Alzheimer's disease, multiple sclerosis, and liver tumors. Growing evidence demonstrates that orphan and adopted orphan nuclear receptors, such as peroxisome proliferator-activated receptors, liver x receptors, the farnesoid x receptor, NR4As, retinoid x receptors, and the pregnane x receptor, regulate the inflammatory and metabolic profiles in a ligand-dependent or -independent manner in human and animal models. This review summarizes the regulatory roles of these nuclear receptors in the inflammatory process and the underlying mechanisms.

Perfluoroalkyl Acids: A Review of Monitoring and Toxicological Findings

In recent years, human and wildlife monitoring studies have identified perfluoroalkyl acids (PFAA) worldwide. This has led to efforts to better understand the hazards that may be inherent in these compounds, as well as the global distribution of the PFAAs. Much attention has focused on understanding the toxicology of the two most widely known PFAAs, perfluorooctanoic acid, and perfluorooctane sulfate. More recently, research was extended to other PFAAs. There has been substantial progress in understanding additional aspects of the toxicology of these compounds, particularly related to the developmental toxicity, immunotoxicity, hepatotoxicity, and the potential modes of action. This review provides an overview of the recent advances in the toxicology and mode of action for PFAAs, and of the monitoring data now available for the environment, wildlife, and humans. Several avenues of research are proposed that would further our understanding of this class of compounds.