Novel diarylheptanoids as inhibitors of TNF-α production.

Synthesis and anti-inflammatory activity of novel diarylheptanoids [5-hydroxy-1-phenyl-7-(pyridin-3-yl)-heptan-3-ones and 1-phenyl-7-(pyridin-3-yl)hept-4-en-3-ones] as inhibitors of tumor necrosis factor-α (TNF-α) production is described in the present article. The key reactions involve the formation of a ß-hydroxyketone by the reaction of substituted 4-phenyl butan-2-ones with pyridine-3-carboxaldehyde in presence of LDA and the subsequent dehydration of the same to obtain the α,ß-unsaturated ketones. Compounds 4i, 5b, 5d, and 5g significantly inhibit lipopolysaccharide (LPS)-induced TNF-α production from human peripheral blood mononuclear cells in a dose-dependent manner. Of note, the in vitro TNF-α inhibition potential of 5b and 5d is comparable to that of curcumin (a naturally occurring diarylheptanoid). Most importantly, oral administration of 4i, 5b, 5d, and 5g (each at 100 mg/kg) but not curcumin (at 100 mg/kg) significantly inhibits LPS-induced TNF-α production in BALB/c mice. Collectively, our findings indicate that these compounds may have potential therapeutic implications for TNF-α-mediated auto-immune/inflammatory disorders.

NF-κB-mediated anti-inflammatory activity of the sesquiterpene lactone 7-hydroxyfrullanolide.

Microarray technology can be used to study the molecular mechanisms of new chemical entities with the aim to develop effective therapeutics. 7-Hydroxyfrullanolide (7HF) is a sesquiterpene lactone that was found to be efficacious in multiple animal models of inflammation by suppression of pro-inflammatory cytokines; however, its molecular mechanism of action remains unclear. We investigated the effects of 7HF on lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells using microarray-based gene expression studies and explored the molecular targets affected. Gene expression profiles and pathway analysis revealed that 7HF potently suppressed multiple inflammatory pathways induced by LPS. More importantly, 7HF was found to inhibit NF-κB related transcripts. These transcripts were further validated using freshly isolated synovial cells from rheumatoid arthritis patients, thus clinically validating our findings. Cell-based imaging and subsequent Western blot analysis demonstrated that 7HF inhibited the translocation of NF-κB into the nucleus by directly inhibiting the phosphorylation of IKK-ß. Since the transcription of adhesion molecules is regulated by NF-κB, further investigation showed that 7HF dose-dependently suppressed ICAM-1, VCAM-1 and E-selectin expression on LPS-stimulated endothelial cells as well as inhibited the adhesion of monocytes to LPS-stimulated endothelial cells. Taken together, our results reveal that 7HF possesses NF-κB inhibitory potential and suggest a likely molecular mechanism of its anti-inflammatory activity.

Phenotypic and genotypic assessment of concomitant drug-induced toxic effects in liver, kidney and blood.

Several studies have characterized drug-induced toxicity in liver and kidney. However, the majority of these studies have been performed with 'individual' organs in isolation. Separately, little is known about the role of whole blood as a surrogate tissue in drug-induced toxicity. Accordingly, we investigated the 'concurrent' response of liver, kidney and whole blood during a toxic assault. Rats were acutely treated with therapeutics (acetaminophen, rosiglitazone, fluconazole, isoniazid, cyclophosphamide, amphotericin B, gentamicin and cisplatin) reported for their liver and/or kidney toxicity. Changes in clinical chemistry parameters (e.g. AST, urea) and/or observed microscopic tissue damage confirmed induced hepatotoxicity and/or nephrotoxicity by all drugs. Drug-induced toxicity was not confined to an 'individual' organ. Not all drugs elicited significant alterations in phenotypic parameters of toxicity (e.g. ALT, creatinine). Accordingly, the transcriptional profile of the organs was studied using a toxicity panel of 30 genes derived from literature. Each of the test drugs generated specific gene expression patterns which were unique for all three organs. Hierarchical cluster analyses of purported hepatotoxicants and nephrotoxicants each led to characteristic 'fingerprints' (e.g. decrease in Cyp3a1 indicative of hepatotoxicity; increase in Spp1 and decrease in Gstp1 indicative of nephrotoxicity). In whole blood cells, a set of genes was derived which closely correlated with individual drug-induced concomitant changes in liver or kidney. Collectively, these data demonstrate drug-induced multi-organ toxicity. Furthermore, our findings underscore the importance of transcriptional profiling during inadequate phenotypic anchorage and suggest that whole blood may be judiciously used as a surrogate for drug-induced extra-hematological organ toxicity.

Effect of nephrotoxicants and hepatotoxicants on gene expression profile in human peripheral blood mononuclear cells.

Studying peripheral blood transcriptome in the quest for translational markers of toxicity is considered to be an attractive offshoot in the field of toxicogenomics. Moreover, it is acknowledged that, xenobiotics which cause a toxic response through similar mechanisms lead to distinctive gene expression patterns. The current study was undertaken to gauge the response of an accessible surrogate tissue, such as blood, to drug-induced perturbations aimed at deriving gene expression patterns. Human peripheral blood mononuclear cells (hPBMC) were exposed to conventional drugs, with reported kidney and/or liver injury, in order to determine their transcriptomic response. Test drugs were divided into two classes viz., drugs affecting kidney (cyclophosphamide, amphotericin B, gentamicin and cisplatin) and liver (acetaminophen, rosiglitazone, fluconazole and isoniazid). After performing gene expression analysis and hierarchical clustering, signature patterns for the two classes were obtained, with a set of 365 genes that can discriminate the two classes of drugs. Our results imply that transcriptional profile of hPBMC get altered as a consequence of drug exposure and unique patterns indicative of specific organ toxicity can hence be deduced. These signature patterns obtained for drugs could be studied for their qualification to identify drug-induced toxicity.

7-hydroxyfrullanolide, a sesquiterpene lactone, inhibits pro-inflammatory cytokine production from immune cells and is orally efficacious in animal models of inflammation.

A promising therapeutic approach to reduce pathological inflammation is to inhibit the increased production of pro-inflammatory cytokines (e.g., TNF-alpha, IL-6). In this study, we investigated the anti-inflammatory potential of 7-hydroxyfrullanolide (7HF). 7HF is an orally bioavailable, small molecule sesquiterpene lactone isolated from the fruit of Sphaeranthus indicus. 7HF significantly and dose-dependently diminished induced and spontaneous production of TNF-alpha and IL-6 from freshly isolated human mononuclear cells, synovial tissue cells isolated from patients with active rheumatoid arthritis and BALB/c mice. Oral administration of 7HF significantly protected C57BL/6J mice against endotoxin-mediated lethality. In the dextran sulfate sodium (DSS) model of murine colitis, oral administration of 7HF prevented DSS-induced weight loss, attenuated rectal bleeding, improved disease activity index and diminished shortening of the colon of C57BL/6J mice. Histological analyses of colonic tissues revealed that 7HF attenuated DSS-induced colonic edema, leukocyte infiltration in the colonic mucosa and afforded significant protection against DSS-induced crypt damage. 7HF was also significantly efficacious in attenuating carrageenan-induced paw edema in Wistar rats after oral administration. In the collagen-induced arthritis in DBA/1J mice, 7HF significantly reduced disease associated increases in articular index and paw thickness, protected against bone erosion and joint space narrowing and prominently diminished joint destruction, hyperproliferative pannus formation and infiltration of inflammatory cells. Collectively, these results provide evidence that 7HF-mediated inhibition of pro-inflammatory cytokines functionally results in marked protection in experimental models of acute and chronic inflammation.

A preferential p110alpha/gamma PI3K inhibitor attenuates experimental inflammation by suppressing the production of proinflammatory mediators in a NF-kappaB-dependent manner.

A promising therapeutic approach to diminish pathological inflammation is to inhibit the increased production and/or biological activity of proinflammatory cytokines (e.g., TNF-alpha, IL-6). The production of proinflammatory cytokines is controlled at the gene level by the activity of transcription factors, such as NF-kappaB. Phosphatidylinositol 3-kinase (PI3K), a lipid kinase, is known to induce the activation of NF-kappaB. Given this, we hypothesized that inhibitors of PI3K activation would demonstrate anti-inflammatory potential. Accordingly, we studied the effects of a preferential p110alpha/gamma PI3K inhibitor (compound 8C; PIK-75) in inflammation-based assays. Mechanism-based assays utilizing human cells revealed that PIK-75-mediated inhibition of PI3K activation is associated with dramatic suppression of downstream signaling events, including AKT phosphorylation, IKK activation, and NF-kappaB transcription. Cell-based assays revealed that PIK-75 potently and dose dependently inhibits in vitro and in vivo production of TNF-alpha and IL-6, diminishes the induced expression of human endothelial cell adhesion molecules (E-selectin, ICAM-1, and VCAM-1), and blocks human monocyte-endothelial cell adhesion. Most importantly, PIK-75, when administered orally in a therapeutic regimen, significantly suppresses the macroscopic and histological abnormalities associated with dextran sulfate sodium-induced murine colitis. The efficacy of PIK-75 in attenuating experimental inflammation is mediated, at least in part, due to the downregulation of pertinent inflammatory mediators in the colon. Collectively, these results provide first evidence that PIK-75 possesses anti-inflammatory potential. Given that PIK-75 is known to exhibit anti-cancer activity, the findings from this study thus reinforce the cross-therapeutic functionality of potential drugs.