An efficient high-throughput screening method for MYST family acetyltransferases, a new class of epigenetic drug targets

Epigenetic aberrations are increasingly regarded as key factors in cancer progression. Recently, deregulation of histone acetyltransferases (HATs) has been linked to several types of cancer. Monocytic leukemia zinc finger protein (MOZ) is a member of the MYST family of HATs, which regulate gene expression in cell proliferation and differentiation. Deregulation of these processes through constitutively active MOZ fusion proteins gives rise to the formation of leukemic stem cells, rendering MOZ an excellent target for treating myeloid leukemia. The authors implemented a hit discovery campaign to identify small-molecule inhibitors of MOZ-HAT activity. They developed a robust, homogeneous assay measuring the acetylation of synthetic histone peptides. In a primary screening campaign testing 243 000 lead-like compounds, they identified inhibitors from several chemical classes. Secondary assays were used to eliminate assay-interfering compounds and prioritize confirmed hits. This study establishes a new high-throughput assay for HAT activity and could provide the foundation for the development of a new class of drugs for the treatment of leukemias.     

The effects of high-dose glutamine ingestion on weightlifting performance

The purpose of this study was to determine if high-dose glutamine ingestion affected weightlifting performance. In a double-blind, placebo-controlled, crossover study, 6 resistance-trained men (mean +/- SE: age, 21.5 +/- 0.3 years; weight, 76.5 +/- 2.8 kg(-1)) performed weightlifting exercises after the ingestion of glutamine or glycine (0.3 g x kg(-1)) mixed with calorie-free fruit juice or placebo (calorie-free fruit juice only). Each subject underwent each of the 3 treatments in a randomized order. One hour after ingestion, subjects performed 4 total sets of exercise to momentary muscular failure (2 sets of leg presses at 200% of body weight, 2 sets of bench presses at 100% of body weight). There were no differences in the average number of maximal repetitions performed in the leg press or bench press exercises among the 3 groups. These data indicate that the short-term ingestion of glutamine does not enhance weightlifting performance in resistance-trained men.     

Ligand-binding activity and expression profile of annexins in Caenorhabditis elegans

Mammalian annexins are implicated in several physiological mechanisms based on their calcium-dependent phospholipid/membrane binding and carbohydrate-binding activities. In this study, we investigated gene expression profiles of all four Caenorhabditis elegans annexins, nex-1, -2, -3 and -4, throughout the development, and compared phospholipid- and carbohydrate-binding properties of their protein products, NEX-1, -2, -3 and -4. We found that nex-1 and -3 are transcribed continuously during the developmental stages, while expression of nex-2 and -4 appeared to be temporal, peaking at the L1 stage followed by a gradual decrease toward the adult stage. NEX-1 and -3 were detected as single protein band in total worm extracts by immunoblotting, but NEX-2 was heterogenic in size. NEX-1, -2, and -3 showed the binding activities to phosphatidylserine, phosphatidylinositol and phosphatidylethanolamine, but not to phosphatidylcholine. In contrast to their uniform phospholipids-binding properties, their glycosaminoglycan-binding activities were distinctive. NEX-2 bound to heparan sulfate and chondroitin, NEX-3 bound only to heparan sulfate, and NEX-1 showed no lectin activities under tested conditions. NEX-4 had neither phospholipids- nor carbohydrate-binding properties. Differentiated expression profiles and ligand-binding properties of NEX-1, -2, -3 and -4, shown in our study, may represent distinctive roles for each C. elegans annexins.     

TNF contributes to the immunopathology of perforin/Fas ligand double deficiency

Perforin (pfp)/Fas ligand (FasL) double-deficient mice have previously been shown to be infertile, lose weight and die prematurely due to tissue destruction caused by a significant inflammatory infiltrate of monocytes/macrophages and T cells. Herein we have compared disease progression in mice additionally deficient in the inflammatory mediator TNF. Unlike pfp/FasL double-deficient mice (TNF+/+ pfp-/- gld), mice lacking functional TNF, FasL and pfp (TNF-/- pfp-/- gld) were comparatively fertile, with the majority of mice not suffering severe pancreatitis or hysterosalphingitis in the first 5 months of life. The mean lifespan of TNF-/- pfp-/- gld mice was 217 +/- 79 days compared with 69 +/- 10 days for TNF+/+ pfp-/- gld mice and the majority of moribund TNF-/- pfp-/- gld mice appeared to die as a result of severe pancreatitis, suggesting that loss of TNF was not completely protective. At 8 weeks of age, characteristics associated with the gld phenotype, such as expansion of B220+ CD4- CD8- T cells, lymphadenopathy and hypergammaglobulinemia were comparable between TNF+/+ pfp-/- gld and TNF-/- pfp-/- gld mice, although the lymphoid organs of TNF+/+ pfp-/- gld mice contained greater numbers of B220+ CD4- CD8- T cells, macrophages and T cells. We conclude that TNF is necessary for the full manifestation of immune dysregulation caused by pfp/FasL-deficiency, in particular in the early and overwhelming tissue infiltration and destruction caused by inflammatory cells.