Intrauterine growth restriction leads to changes in sulfur amino acid metabolism, but not global DNA methylation, in Yucatan miniature piglets

Intrauterine growth restriction (IUGR), in both animals and humans, has been linked to metabolic syndrome later in life. There has been recent evidence that perturbations in sulfur amino acid metabolism may be involved in this early programming phenomenon. Methionine is the precursor for cellular methylation reactions and for the synthesis of cysteine. It has been suggested that the mechanism behind the "fetal origins" of adult diseases may be epigenetic, involving DNA methylation. Because we have recently demonstrated the fetal origins phenomenon in Yucatan miniature swine, we hypothesized that sulfur amino acid metabolism is altered in IUGR piglets. In this study, metabolites and the activities of sulfur amino acid cycle enzymes were analyzed in liver samples of 3- to 5-day-old runt (IUGR: 0.85±0.13 kg) and large (1.36±0.21 kg) Yucatan miniature pig littermates (n=6 pairs). The IUGR piglets had significantly lower specific and total activities of betaine-homocysteine methyltransferase (BHMT) and cystathionine γ-lyase (CGL) than larger littermates (P<.05). Expression of CGL (but not BHMT) mRNA was also lower in IUGR piglets (P<.05). This low CGL reduced cysteine and taurine concentrations in IUGR pigs and led to an accumulation of hepatic cystathionine, with lower homocysteine concentrations. Methylation index and liver global DNA methylation were unaltered. Reduced prenatal growth in Yucatan miniature piglets impairs their remethylation capacity as well as their ability to remove cystathionine and synthesize cysteine and taurine, which could have important implications on long-term health outcomes of IUGR neonates.     

All politics is local: the case of Macrocephalon maleo conservation on Sulawesi, Indonesia

The rich biodiversity of the Indonesian island of Sulawesi is subject to a high rate of deforestation and other pressures. Its plight is symbolized by the deteriorating conservation status of the maleo, an iconic galliform bird that is both striking in appearance and intimately bound up with local traditions. After a series of international-led projects during the 1980s and early 1990s conservation efforts petered out until recently when there has been an upsurge in local-led concern and action. To capitalize on this a workshop was held in 2010 to share local perceptions, lessons and concerns about the species and these conservation efforts. The workshop was dominated by members of local communities and their elected or traditional representatives, although there was also a wide variety of other stakeholders present, including from national species conservation and local government agencies. Whilst there is a need for more information to underpin the actions necessary to ensure the survival of this species, the overwhelming perception of participants was that continued decentralization of policy making and budgetary responsibility would enhance the conservation efforts for this species (and other elements of biodiversity) considerably. This would allow the upsurge in locally-led conservation activities to be continued and expanded.     

Finger loop inhibitors of the HCV NS5b polymerase. Part II. Optimization of tetracyclic indole-based macrocycle leading to the discovery of TMC647055

Optimization of a novel series of macrocyclic indole-based inhibitors of the HCV NS5b polymerase targeting the finger loop domain led to the discovery of lead compounds exhibiting improved potency in cellular assays and superior pharmacokinetic profile. Further lead optimization performed on the most promising unsaturated-bridged subseries provided the clinical candidate 27-cyclohexyl-12,13,16,17-tetrahydro-22-methoxy-11,17-dimethyl-10,10-dioxide-2,19-methano-3,7:4,1-dimetheno-1H,11H-14,10,2,9,11,17-benzoxathiatetraazacyclo docosine-8,18(9H,15H)-dione, TMC647055 (compound 18a). This non-zwitterionic 17-membered ring macrocycle combines nanomolar cellular potency (EC(50) of 82 nM) with minimal associated cell toxicity (CC(50)>20 μM) and promising pharmacokinetic profiles in rats and dogs. TMC647055 is currently being evaluated in the clinic.     

p14ARF Post-Transcriptional Regulation of Nuclear Cyclin D1 in MCF-7 Breast Cancer Cells: Discrimination between a Good and Bad Prognosis?

As part of a cell's inherent protection against carcinogenesis, p14ARF is upregulated in response to hyperproliferative signalling to induce cell cycle arrest. This property makes p14ARF a leading candidate for cancer therapy. This study explores the consequences of reactivating p14ARF in breast cancer and the potential of targeting p14ARF in breast cancer treatment. Our results show that activation of the p14ARF-p53-p21-Rb pathway in the estrogen sensitive MCF-7 breast cancer cells induces many hallmarks of senescence including a large flat cell morphology, multinucleation, senescence-associated-β-gal staining, and rapid G1 and G2/M phase cell cycle arrest. P14ARF also induces the expression of the proto-oncogene cyclin D1, which is most often associated with a transition from G1-S phase and is highly expressed in breast cancers with poor clinical prognosis. In this study, siRNA knockdown of cyclin D1, p21 and p53 show p21 plays a pivotal role in the maintenance of high cyclin D1 expression, cell cycle and growth arrest post-p14ARF induction. High p53 and p14ARF expression and low p21/cyclin D1 did not cause cell-cycle arrest. Knockdown of cyclin D1 stops proliferation but does not reverse senescence-associated cell growth. Furthermore, cyclin D1 accumulation in the nucleus post-p14ARF activation correlated with a rapid loss of nucleolar Ki-67 protein and inhibition of DNA synthesis. Latent effects of the p14ARF-induced cellular processes resulting from high nuclear cyclin D1 accumulation included a redistribution of Ki-67 into the nucleoli, aberrant nuclear growth (multinucleation), and cell proliferation. Lastly, downregulation of cyclin D1 through inhibition of ER abrogated latent recurrence. The mediation of these latent effects by continuous expression of p14ARF further suggests a novel mechanism whereby dysregulation of cyclin D1 could have a double-edged effect. Our results suggest that p14ARF induced-senescence is related to late-onset breast cancer in estrogen responsive breast cancers and/or the recurrence of more aggressive breast cancer post-therapy.     

Discovery of novel potent and selective dipeptide hepatitis C virus NS3/4A serine protease inhibitors

Starting from the previously reported HCV NS3/4A protease inhibitor BILN 2061, we have used a fast-follower approach to identify a novel series of HCV NS3/4A protease inhibitors in which (i) the P3 amino moiety and its capping group have been truncated, (ii) a sulfonamide is introduced in the P1 cyclopropyl amino acid, (iii) the position 8 of the quinoline is substituted with a methyl or halo group, and (iv) the ring size of the macrocycle has been reduced to 14 atoms. SAR analysis performed with a limited set of compounds led to the identification of N-{17-[8-chloro-2-(4-isopropylthiazol-2-yl)-7-methoxyquinolin-4-yloxy]-2,14-dioxo-3,15-diazatricyclo [13.3.0.0 [Bartenschlager, R.; Lohmann, V. J. Gen. Virol. 2000, 81, 1631; Vincent Soriano, Antonio Madejon, Eugenia Vispo, Pablo Labarga, Javier Garcia-Samaniego, Luz Martin-Carbonero, Julie Sheldon, Marcelle Bottecchia, Paula Tuma, Pablo Barreiro Expert Opin. Emerg. Drugs, 2008, 13, 1-19]]octadec-7-ene-4-carbonyl}(1-methylcyclopropyl)(1-methylcyclopropyl)sulfonamide 19l an extremely potent (K(i)=0.20 nM, EC(50)=3.7 nM), selective, and orally bioavailable dipeptide NS3/4A protease inhibitor, which has features attractive for further preclinical development.