Inhibitors of HIV protease: Unique non-peptide active site templates

New templates were designed and prepared which straddle the active site of HIV-1 protease. These templates were designed to be ‘flexible scaffolds’ upon which substituents could be appended to fill the pockets of HIV protease. The new templates prepared and analysed were 4-hydroxy-5H-furan-2-ones, 4-hydroxy-5,6-dihydropyrones, 3-hydroxy-cyclohex-2-enones, and 4-hydroxy-2(1H)-pyridinones, of which the 4-hydroxy- 5,6-dihydropyrones were found to be the most potent inhibitors of HIV-1 protease.     

A transfection compound series based on a versatile Tris linkage

The family of cationic lipid transfection reagents described here demonstrates a modular design that offers potential for the ready synthesis of a wide variety of molecular variants. The key feature of these new molecules is the use of Tris as a linker for joining the hydrophobic domain to a cationic head group. The molecular design offers the opportunity to conveniently synthesise compounds differing in charge, the number and nature of hydrophobic groups in the hydrophobic domain and the characteristics of the spacer between the cationic and hydrophobic moieties. We show that prototype reagents of this design can deliver reporter genes into cultured cells with efficiencies rivaling those of established cationic lipid transfection reagents. A feature of these reagents is that they are not dependent on formulation with a neutral lipid for activity.     

Genome-wide linkage analysis replicates susceptibility locus for fasting plasma triglycerides: NHLBI Family Heart Study

Recent reports implicate chromosomal regions linked to inter-individual variation in plasma triglycerides. We conducted genome-wide scans to replicate these linkages and/or identify other loci influencing plasma triglycerides in the NHLBI Family Heart Study (FHS). Data were obtained for 501 three-generational families. Genotyping was done by the Utah Molecular Genetics Laboratory and NHLBI Mammalian Genotyping Service; markers from both were placed on one genetic map. Analysis was done using multipoint variance components linkage. Fasting plasma triglycerides were log-transformed and age-, sex-, and field center-adjusted; suggestive linkage evidence was found on chromosome 8 (LOD=2.80 at 89 cM, marker D8S1141). Further adjustment for waist girth, BMI, diabetes, hypertension, and lipid-lowering drugs suggested linkage regions on chromosomes 6 (LOD=2.29 at 79 cM, marker D6S295) and 15 (LOD=1.85 at 43 cM, marker D15S659). Since HDL is correlated with triglycerides and because it was linked to this region on chromosome 15 in FHS, we created a composite triglyceride–HDL phenotype. The combined phenotype LOD score was 3.0 at the same marker on chromosome 15. Chromosome 15 likely harbors a susceptibility locus with an influence on triglycerides and HDL. Regions on chromosomes 6 and 8 may also contain loci contributing to inter-individual variation in plasma triglycerides.     

Tobacco transgenic for the flax rust resistance gene L expresses allele-specific activation of defense responses

Tobacco was transformed with three different alleles (L2, L6, and L10) of the flax rust resistance gene L, a member of the toll interleukin-1 receptor, nucleotide-binding site, leucine-rich repeat (TIR-NBS-LRR) class of plant disease resistance genes. L6 transgenics had a stunted phenotype, expressed several defense response genes constitutively, and had increased resistance to the fungus Cercospora nicotianae and the oomycete Phytophthora parasitica pv. nicotianae. L2 and L10 transgenics, with one exception for L10, did not express these phenotypes, indicating that the activation of tobacco defense responses is L6 allele-specific. The phenotype of the exceptional L10 transgenic plant was associated with the presence of a truncated L10 gene resulting from an aberrant T-DNA integration. The truncated gene consisted of the promoter, the complete TIR region, and 39 codons of the NBS domain fused inframe to a tobacco retrotransposon-like sequence. A similar truncated L10 gene, constructed in vitro, was transiently expressed in tobacco leaves and gave rise to a strong localized necrotic reaction. Together, these results suggest that defense signaling properties of resistance genes can be expressed in an allele-specific and pathogen-independent manner when transferred between plant genera.     

Activin redux: specification of mesodermal pattern in Xenopus by graded concentrations of endogenous activin B

Mesoderm formation in the amphibian embryo occurs through an inductive interaction in which cells of the vegetal hemisphere of the embryo act on overlying equatorial cells. The first candidate mesoderm-inducing factor to be identified was activin, a member of the transforming growth factor type beta family, and it is now clear that members of this family are indeed involved in mesoderm and endoderm formation. In particular, Derrière and five nodal-related genes are all considered to be strong candidates for endogenous mesoderm-inducing agents. Here, we show that activin, the function of which in mesoderm induction has hitherto been unclear, also plays a role in mesoderm formation. Inhibition of activin function using antisense morpholino oligonucleotides interferes with mesoderm formation in a concentration-dependent manner and also changes the expression levels of other inducing agents such as Xnr2 and Derrière. This work reinstates activin as a key player in mesodermal patterning. It also emphasises the importance of checking for polymorphisms in the 5' untranslated region of the gene of interest when carrying out antisense morpholino experiments in Xenopus laevis.     

Molecular activity of 1,25-dihydroxyvitamin D3 in primary cultures of human prostatic epithelial cells revealed by cDNA microarray analysis

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] exerts anti-proliferative, differentiating and apoptotic effects on prostatic cells. These activities, in addition to epidemiologic findings that link Vitamin D to prostate cancer risk, support the use of 1,25(OH)(2)D(3) for prevention or therapy of prostate cancer. The molecular mechanisms by which 1,25(OH)(2)D(3) exerts antitumor effects on prostatic cells are not well-defined. In addition, there is heterogeneity among the responses of various prostate cell lines and primary cultures to 1,25(OH)(2)D(3) with regard to growth inhibition, differentiation and apoptosis. To understand the basis of these differential responses and to develop a better model of Vitamin D action in the prostate, we performed cDNA microarray analyses of primary cultures of normal and malignant human prostatic epithelial cells, treated with 50 nM of 1,25(OH)(2)D(3) for 6 and 24 h. CYP24 (25-hydroxyvitamin D(3)-24-hydroxylase) was the most highly upregulated gene. Significant and early upregulation of dual specificity phosphatase 10 (DUSP10), validated in five additional primary cultures, points to inhibition of members of the mitogen-activated protein kinase (MAPK) superfamily as a key event mediating activity of 1,25(OH)(2)D(3) in prostatic epithelial cells. The functions of other regulated genes suggest protection by 1,25(OH)(2)D(3) from oxidative stress. Overall, these results provide new insights into the molecular basis of antitumor activities of Vitamin D in prostate cells.     

Infarction alters both the distribution and noradrenergic properties of cardiac sympathetic neurons

Regional changes occur in the sympathetic innervation of the heart after myocardial infarction (MI), including loss of norepinephrine (NE) uptake and depletion of neuronal NE. This apparent denervation is accompanied by increased cardiac NE spillover. One potential explanation for these apparently contradictory findings is that the sympathetic neurons innervating the heart are exposed to environmental stimuli that alter neuronal function. To understand the changes that occur in the innervation of the heart after MI, immunohistochemical, biochemical, and molecular analyses were carried out in the heart and stellate ganglia of control and MI rats. Immunohistochemistry with panneuronal markers revealed extensive denervation in the left ventricle (LV) below the infarct, but sympathetic nerve fibers were retained in the base of the heart. Western blot analysis revealed that tyrosine hydroxylase (TH) expression (normalized to a panneuronal marker) was increased significantly in the base of the heart and in the stellate ganglia but decreased in the LV below the MI. NE transporter (NET) binding sites, normalized to total protein, were unchanged, except in the LV, where [3H]nisoxetine binding was decreased. TH mRNA was increased significantly in the left and right stellate ganglia after MI, while NET mRNA was not. In the base of the heart, increased TH coupled with no change in NET may explain the increase in extracellular NE observed after MI. Coupled with substantial denervation in the LV, these changes likely contribute to the onset of cardiac arrhythmias.     

Lack of Apparent Neurological Abnormalities in Rabbits Sensitized by Gangliosides

Two very high titer polyclonal antibodies against two ganglioside antigens, GM1 and GD1a, have been raised in New Zealand white rabbits using a homogeneous suspension of the highly purified antigens in Keyhole Limpet Hemocyanin and Freunds adjuvant. The antisera were prepared over a period of 6 months with repeated injections of the ganglioside suspension, followed by an intravenous injection of the purified ganglioside solution, and collecting the serum (approximately 50 ml) at defined time intervals. The GM1-antibody, thus prepared, showed a cross reactivity toward GD1b and asialo-GM1 (GA1), while the GD1a-antibody reacted with GD1a, GM1 and GA1 and GD1b as determined by immuno-overlay and ELISA methods. The titer for GM1 antiserum, determined by ELISA, was greater than 1/10,000 dilution while the titer for GD1a antibody was greater than 1/5,000 dilution. No neurological or behavioral abnormality was observed during the period of antiserum production. To evaluate any likely pathological damage caused by such a high titer ganglioside-antibody, autopsy of CNS as well PNS tissues from the rabbits were carried out after the final bleeding. No obvious pathological changes, including demyelination, were noted in any of the four rabbits. These observations cast doubt as to the direct effect of anti-ganglioside antibody induced neurological and pathological disorders.Special issue dedicated to Lawrence F. Eng.