Sphingomyelin metabolites inhibit sphingomyelin synthase and CTP:phosphocholine cytidylyltransferase

Tissue injury in inflammation involves the release of several cytokines that activate sphingomyelinases and generate ceramide. In the lung, the impaired metabolism of surfactant phosphatidylcholine (PC) accompanies this acute and chronic injury. These effects are long-lived and extend beyond the time frame over which tumor necrosis factor (TNF)-alpha and interleukin-1beta are elevated. In this paper, we demonstrate that in H441 lung cells these two processes, cytokine-induced metabolism of sphingomyelin and the inhibition of PC metabolism, are directly interrelated. First, metabolites of sphingomyelin hydrolysis themselves inhibit key enzymes necessary for restoring homeostasis between sphingomyelin and its metabolites. Ceramide stimulates sphingomyelinases as effectively as TNF-alpha, thereby amplifying the sphingomyelinase activation, and TNF-alpha, ceramide, and sphingosine all inhibit PC:ceramide phosphocholine transferase (sphingomyelin synthase), the enzyme that restores homeostasis between sphingomyelin and ceramide pools. Second, ceramide inhibits PC synthesis, probably because of its effects on CTP:phosphocholine cytidylyltransferase, the rate-limiting enzymatic step in de novo PC synthesis. The data presented here suggest that TNF-alpha may be an inhibitor of phospholipid metabolism in inflammatory tissue injury. These actions may be amplified because of the ability of metabolites of sphingomyelin to inhibit the pathways that should restore the normal ceramide-sphingomyelin homeostasis.     

Design,synthesis and evaluation of constrained tetrahydroimidazopyrimidine derivatives as antagonists of corticotropin-releasing factor type 1 receptor (CRF1R)

Several tetrahydroimidazopyrimidines were prepared using silver assisted cyclization as the key step. The binding affinities of compounds thus prepared were evaluated in vitro toward hCRF₁R. Initial lead compound 16 (K_i = 32 nM) demonstrated modest putative anxiolytic effects in the mouse canopy test. Further optimization using parallel synthesis provided compounds with K_i’s <50 nM.     

Effects of a low-intensity electromagnetic field on fibroblast migration and proliferation

The aim of this study was to test if an extremely weak 1?GHz electromagnetic field (EMF), known to be in resonance with clusters of water molecules, has biological effects on human fibroblasts. We demonstrated that in an in vitro model of wound healing, this EMF can activate fibroblast migration. [(3)H]thymidine incorporation experiments demonstrated that the EMF could also activate fibroblast proliferation. Activation of the expression of human fibroblast growth factor 1 (HFGF1) after EMF exposure showed that molecular wound healing pathways are activated in response to this water-resonant EMF.     

Quantitative immunoproteomics analysis reveals novel MHC class I presented peptides in cisplatin-resistant ovarian cancer cells

Platinum-based chemotherapy is widely used to treat various cancers including ovarian cancer. However, the mortality rate for patients with ovarian cancer is extremely high, largely due to chemo-resistant progression in patients who respond initially to platinum based chemotherapy. Immunotherapy strategies, including antigen specific vaccines, are being tested to treat drug resistant ovarian cancer with variable results. The identification of drug resistant specific tumor antigens would potentially provide significant improvement in effectiveness when combined with current and emerging therapies. In this study, using an immunoproteomics method based on iTRAQ technology and an LC-MS platform, we identified 952 MHC class I presented peptides. Quantitative analysis of the iTRAQ labeled MHC peptides revealed that cisplatin-resistant ovarian cancer cells display increased levels of MHC peptides derived from proteins that are implicated in many important cancer pathways. In addition, selected differentially presented epitope specific CTL recognize cisplatin-resistant ovarian cancer cells significantly better than the sensitive cells. These over-presented, drug resistance specific MHC class I associated peptide antigens could be potential targets for the development of immunotherapeutic strategies for the treatment of ovarian cancer including the drug resistant phenotype.     

Optimized culture conditions for bacteriocin production by Pediococcus acidilactici LAB 5 and its characterization

A strain of Pediococcus acidilactici LAB 5 was isolated from vacuum-packed fermented meat product, in order to obtain a novel bacteriocin from food-grade organisms. Optimized culture conditions for bacteriocin production in different media (viz., MRS, TGE, TGE + buffer, TGE + Tween 80, and TGE + Tween 80 + buffer) and at different temperatures and pH conditions were reported. TGE + Tween 80 + buffer medium was found to be most effective for bacteriocin production (about 2400 AU/ml) by this strain, when incubated at 37 degrees C for 24 h. Bacteriocin, partially purified by adsorption-desorption method showed molecular mass of 10.3 kDa and produced prominent inhibition zone in activity gel. It showed significant storage stability both at high as well as in low temperatures for up to 6 months and retained its activity in a number of organic solvents, except in 2-mercaptoethanol. The treatment with amylase and lysozyme did not change its activity, but it lost its activity on proteinase K treatment. Antibacterial efficacy of bacteriocin was proved against some food spoilage and human pathogenic bacteria like Enterococcus, Leuconostoc, Listeria, Staphylococcus and Streptococcus.     

Isolation and Characterization of Pediocin NV 5 Producing <Emphasis Type="Italic">Pediococcus acidilactici</Emphasis> LAB 5 from Vacuum-Packed Fermented Meat Product

A potentially novel antimicrobial compound producing Pediococcus acidilactici LAB 5 was isolated from vacuum-packed fermented meat product. This compound was found active against some species of Enterococcus, Leuconostoc, Staphylococcus and Listeria, many of which are associated with food spoilage and food related health hazards. The strain was found to be a paired cocci which can utilize a broad range of carbohydrates and produce acid identical to the P. acidilactici and P. pentoseus. Since the antimicrobial agent was sensitive to proteolytic enzymes but quite resistant to heat, it was identified as a bacteriocin and was designated as Pediocin NV 5. The molecular weight of the bacteriocin was 10.3 kDa and the bacterium possessed a 5 kbp plasmid responsible for bacteriocin production and also for vancomycin resistance phenotype.     

Discovery of 6-chloro-2-trifluoromethyl-7-aryl-7H-imidazo[1,2-a]imidazol-3-ylmethylamines,a novel class of corticotropin-releasing factor receptor type 1 (CRF1R) antagonists

A novel series of [6-chloro-2-trifluoromethyl-7-aryl-7H-imidazo[1,2-a]imidazol-3-ylmethyl]-dialkylamines was discovered as potent CRF₁R antagonists. The optimization of binding affinity in the series by the parallel reaction approach is discussed herein.