Substance P is associated with heart enlargement and apoptosis in murine dilated cardiomyopathy induced by Taenia crassiceps infection

Dilated cardiomyopathy (degeneration of heart muscle and heart enlargement) is an important cause of heart failure among young adults. Dilated cardiomyopathy may be a complication during or after various viral, bacterial, or parasitic diseases. Substance P (SP) is a neurotransmitter that is involved in the pathogenesis of various diseases. To determine whether SP is associated with cardiac changes in murine cysticercosis, we compared heart-weight to body-weight ratio, cardiac pathology, cardiomyocyte size, and cardiac-apoptosis (TUNEL assay) in hearts from Taenia crassiceps-infected (wild-type vs. SP-knockout) mice. We noted that, as compared with control uninfected wild-type mice, elevated protein levels of SP and its receptor as studied by ELISA or immunohistochemistry, respectively, were elevated in the hearts of parasite-infected wild-type mice. The heart-weight to body-weight ratios were significantly higher in the parasite-infected wild-type mice versus those of the infected SP-knockout mice. Furthermore, wild-type infected mice developed dilated cardiomyopathy with increased chamber size of both ventricles, decreased ventricular wall thickness, compensatory cardiomyocyte hypertrophy, and increased cardiac apoptosis. This cardiac pathology did not develop in mice lacking SP activity (i.e., in infected SP knockout mice) or in uninfected mice. These data indicate that SP is associated with cardiac changes in an animal model of parasitic dilated cardiomyopathy.     

Ebola virus glycoprotein 1: identification of residues important for binding and postbinding events

The filoviruses Ebola virus (EBOV) and Marburg virus (MARV) are responsible for devastating hemorrhagic fever outbreaks. No therapies are available against these viruses. An understanding of filoviral glycoprotein 1 (GP1) residues involved in entry events would facilitate the development of antivirals. Towards this end, we performed alanine scanning mutagenesis on selected residues in the amino terminus of GP1. Mutant GPs were evaluated for their incorporation onto feline immunodeficiency virus (FIV) particles, transduction efficiency, receptor binding, and ability to be cleaved by cathepsins L and B. FIV virions bearing 39 out of 63 mutant glycoproteins transduced cells efficiently, whereas virions bearing the other 24 had reduced levels of transduction. Virions pseudotyped with 23 of the poorly transducing GPs were characterized for their block in entry. Ten mutant GPs were very poorly incorporated onto viral particles. Nine additional mutant GPs (G87A/F88A, K114A/K115A, K140A, G143A, P146A/C147A, F153A/H154A, F159A, F160A, and Y162A) competed poorly with wild-type GP for binding to permissive cells. Four of these nine mutants (P146A/C147A, F153A/H154A, F159A, and F160A) were also inefficiently cleaved by cathepsins. An additional four mutant GPs (K84A, R134A, D150A, and E305/E306A) that were partially defective in transduction were found to compete effectively for receptor binding and were readily cleaved by cathepsins. This finding suggested that this latter group of mutants might be defective at a postbinding, cathepsin cleavage-independent step. In total, our study confirms the role of some GP1 residues in EBOV entry that had previously been recognized and identifies for the first time other residues that are important for productive entry.     

Phosphatidylinositol ether lipid analogues that inhibit AKT also independently activate the stress kinase, p38alpha, through MKK3/6-independent and -dependent mechanisms

Previously, we identified five active phosphatidylinositol ether lipid analogues (PIAs) that target the pleckstrin homology domain of Akt and selectively induce apoptosis in cancer cells with high levels of Akt activity. To examine specificity, PIAs were screened against a panel of 29 purified kinases. No kinase was inhibited, but one isoform of p38, p38alpha, was uniformly activated 2-fold. Molecular modeling of p38alpha revealed the presence of two regions that could interact with PIAs, one in the activation loop and a heretofore unappreciated region in the upper lobe that resembles a pleckstrin homology domain. In cells, two phases of activation were observed, an early phase that was independent of the upstream kinase MKK3/6 and inhibited by the p38 inhibitor SB203580 and a latter phase that was coincident with MKK3/6 activation. In short term xenograft experiments that employed immunohistochemistry and immunoblotting, PIA administration increased phosphorylation of p38 but not MKK3/6 in tumors in a statistically significant manner. Although PIAs rapidly activated p38 with similar time and dose dependence as Akt inhibition, p38 activation and Akt inhibition were independent events induced by PIAs. Using SB203580 or p38alpha(-/-) cells, we showed that p38alpha is not required for PIA-induced apoptosis but is required for H(2)O(2)- and anisomycin-induced apoptosis. Nonetheless, activation of p38a contributes to PIA-induced apoptosis, because reconstitution of p38a into p38alpha(-/-) cells increased apoptosis. These studies indicate that p38alpha is activated by PIAs through a novel mechanism and show that p38alpha activation contributes to PIA-induced cell death. Independent modulation of Akt and p38alpha could account for the profound cytotoxicity of PIAs.     

Energy expenditure and influence of physiologic factors during marathon running

This study examined energy expenditure and physiologic determinants for marathon performance in recreational runners. Twenty recreational marathon runners participated (10 males aged 41 +/- 11.3 years, 10 females aged 42.7 +/- 11.7 years). Each subject completed a V(.-)O2max and a 1-hour treadmill run at recent marathon pace, and body composition was indirectly determined via dual energy X-ray absorptiometry. The male runners exhibited higher V(.-)O2max (ml x kg(-1) x min(-1)) values (52.6 +/- 5.5) than their female counterparts (41.9 +/- 6.6), although ventilatory threshold (T-vent) values were similar between groups (males: 76.2 +/- 6.1 % of V(.-)O2max, females: 75.1 +/- 5.1%). The male runners expended more energy (2,792 +/- 235 kcal) for their most recent marathon as calculated from the 1-hour treadmill run at marathon pace than the female runners (2,436 +/- 297 kcal). Body composition parameters correlated moderately to highly (r ranging from 0.50 to 0.87) with marathon run time. Also, V(.-)O2max (r = -0.73) and ventilatory threshold (r = -0.73) moderately correlated with marathon run time. As a group, the participants ran near their ventilatory threshold for their most recent marathon (r = 0.74). These results indicate the influence of body size on marathon run performance. In general, the larger male and female runners ran slower and expended more kilocalories than smaller runners. Regardless of marathon finishing time, the runners maintained a pace near their T-vent, and as T-vent or V(.-)O2max increased, marathon performance time decreased.     

Synthesis and enantioselective rearrangement of (Z)-4-triphenylmethoxy-2,3-epoxybutan-1-ol enantiomers

Efficient enzyme catalyzed kinetic resolutions of a synthetically useful chiral building block, (Z)-4-triphenylmethoxy-2,3-epoxybutan-1-ol, are reported. The highest selectivities were achieved by Lipozyme TL IM and Amano Lipase PS enzymes in the presence of vinyl acetate. Enantiomeric enrichment of the optically active acetate isomer was accomplished by selective crystallization of the racemic part of the enantiomeric mixture. Enzyme catalyzed hydrolysis of the acetate also provided an optically pure epoxybutanol derivative. O-Benzylation of (+)-(Z)-1-hydroxy-4-triphenylmethoxy-2,3-epoxybutane followed by super base promoted diastereo- and enantio-selective rearrangement resulted in (+)-(2R,3R,1'R)-3-[1-hydroxy-2-(triphenylmethoxy)ethyl]-2-phenyloxetane in >98% ee and de. Configurations of the new optically active products were determined by chemical correlation.     

Rybp,a polycomb complex-associated protein,is required for mouse eye development

Background  

Rybp (Ring1 and YY1 binding protein) is a zinc finger protein which interacts with the members of the mammalian polycomb complexes. Previously we have shown that Rybp is critical for early embryogenesis and that haploinsufficiency of Rybp in a subset of embryos causes failure of neural tube closure. Here we investigated the requirement for Rybp in ocular development using four in vivo mouse models which resulted in either the ablation or overexpression of Rybp.     

Phase 0 clinical trials in cancer drug development: from FDA guidance to clinical practice

The Food and Drug Administration (FDA) recently introduced the Exploratory Investigational New Drug Guidance to expedite the clinical evaluation of new therapeutic and imaging agents. Early clinical studies performed under the auspices of this guidance, so-called "Phase 0" trials, have been initiated at the National Cancer Institute to integrate qualified pharmacodynamic biomarker assays into first-in-human cancer clinical trials of molecularly targeted agents. The goal of this integration is to perform molecular proof-of-concept investigations at the earliest stage of cancer drug development. Phase 0 trials do not offer any possibility of patient benefit; instead, intensive, real-time pharmacodynamic and pharmacokinetic analyses of patient tumor samples and/or surrogate tissues are performed to inform subsequent trials. Phase 0 studies do not replace formal Phase I drug safety testing and require a substantial investment of resources in assay development early on; however, they offer the promise of more rational selection of agents for further, large-scale development as well as the molecular identification of potential therapeutic failures early in the development process.