Vaccination response to tetanus toxoid and 23-valent pneumococcal vaccines following administration of a single dose of abatacept: a randomized,open-label,parallel group study in healthy subjects

The effect of abatacept, a selective T-cell co-stimulation modulator, on vaccination has not been previously investigated. In this open-label, single-dose, randomized, parallel-group, controlled study, the effect of a single 750 mg infusion of abatacept on the antibody response to the intramuscular tetanus toxoid vaccine (primarily a memory response to a T-cell-dependent peptide antigen) and the intramuscular 23-valent pneumococcal vaccine (a less T-cell-dependent response to a polysaccharide antigen) was measured in 80 normal healthy volunteers. Subjects were uniformly randomized to receive one of four treatments: Group A (control group), subjects received vaccines on day 1 only; Group B, subjects received vaccines 2 weeks before abatacept; Group C, subjects received vaccines 2 weeks after abatacept; and Group D, subjects received vaccines 8 weeks after abatacept. Anti-tetanus and anti-pneumococcal (Danish serotypes 2, 6B, 8, 9V, 14, 19F and 23F) antibody titers were measured 14 and 28 days after vaccination. While there were no statistically significant differences between the dosing groups, geometric mean titers following tetanus or pneumococcal vaccination were generally lower in subjects who were vaccinated 2 weeks after receiving abatacept, compared with control subjects. A positive response (defined as a twofold increase in antibody titer from baseline) to tetanus vaccination at 28 days was seen, however, in ≥ 60% of subjects across all treatment groups versus 75% of control subjects. Similarly, over 70% of abatacept-treated subjects versus all control subjects (100%) responded to at least three pneumococcal serotypes, and approximately 25–30% of abatacept-treated subjects versus 45% of control subjects responded to at least six serotypes.     

Maternal diabetes induces congenital heart defects in mice by altering the expression of genes involved in cardiovascular development

Background

Congenital heart defects are frequently observed in infants of diabetic mothers, but the molecular basis of the defects remains obscure. Thus, the present study was performed to gain some insights into the molecular pathogenesis of maternal diabetes-induced congenital heart defects in mice.

Methods and results

We analyzed the morphological changes, the expression pattern of some genes, the proliferation index and apoptosis in developing heart of embryos at E13.5 from streptozotocin-induced diabetic mice. Morphological analysis has shown the persistent truncus arteriosus combined with a ventricular septal defect in embryos of diabetic mice. Several other defects including defective endocardial cushion (EC) and aberrant myofibrillogenesis have also been found. Cardiac neural crest defects in experimental embryos were analyzed and validated by the protein expression of NCAM and PGP 9.5. In addition, the protein expression of Bmp4, Msx1 and Pax3 involved in the development of cardiac neural crest was found to be reduced in the defective hearts. The mRNA expression of Bmp4, Msx1 and Pax3 was significantly down-regulated (p < 0.001) in the hearts of experimental embryos. Further, the proliferation index was significantly decreased (p < 0.05), whereas the apoptotic cells were significantly increased (p < 0.001) in the EC and the ventricular myocardium of the experimental embryos.

Conclusion

It is suggested that the down-regulation of genes involved in development of cardiac neural crest could contribute to the pathogenesis of maternal diabetes-induced congenital heart defects.     

Characterization of a novel gene for strain typing reveals substructuring of Aspergillus fumigatus across North America

Fifty-five epidemiologically linked Aspergillus fumigatus isolates obtained from six nosocomial outbreaks of invasive aspergillosis were subtyped by sequencing the polymorphic region of the gene encoding a putative cell surface protein, Afu3g08990 (denoted as CSP). Comparative sequence analysis showed that genetic diversity was generated in the coding region of this gene by both tandem repeats and point mutations. Each unique sequence in an outbreak cluster was assigned an arbitrary number or CSP sequence type. The CSP typing method was able to identify "clonal" and genotypically distinct A. fumigatus isolates, and the results of this method were concordant with those of another discriminatory genotyping technique, the Afut1 restriction fragment length polymorphism typing method. The novel single-locus sequence typing (CSP typing) strategy appears to be a simple, rapid, discriminatory tool that can be readily shared across laboratories. In addition, we found that A. fumigatus isolates substructured into multiple clades; interestingly, one clade consisted of isolates predominantly representing invasive clinical isolates recovered from cardiac transplant patients from two different outbreak situations. We also found that the A. fumigatus isolate Af293, whose genome has been sequenced, possesses a CSP gene structure that is substantially different from those of the other A. fumigatus strains studied here, highlighting the need for further taxonomic study.     

Study of the inhibition of cyclin-dependent kinases with roscovitine and indirubin-3′-oxime from molecular dynamics simulations

Molecular dynamics simulations were performed to elucidate the interactions of CDK2 and CDK5 complexes with three inhibitors: R-roscovitine, S-roscovitine, and indirubin-3′-oxime. The preference of the two complexes for R-roscovitine over the S enantiomer, as reported by the experiment, was also found by the simulations. More importantly, the simulations showed that the cause of the stronger affinity for the R enantiomer is the presence of an important hydrogen bond between R-roscovitine and the kinases not found with S-roscovitine. The simulations also showed two amino acid mutations in the active site of CDK5/R-roscovitine that favor binding-enhanced electrostatic contributions, making the inhibitor more effective for CDK5 than for CDK2. This suggests that the effectiveness of roscovitine-like inhibitors can be improved by enhancing their electrostatic interaction with the kinases. Finally, molecular mechanics–Possion–Boltzmann/surface area calculations of the CDK5/indirubin-3′-oxime system in both water-excluded and water-included environments gave significantly different electrostatic contributions to the binding. The simulations detected the displacement of a water molecule in the active site of the water-included CDK/indirubin-3′-oxime system. This resulted in a more conserved binding pattern than the water-excluded structure. Hence, in the design of new indirubin-like inhibitors, it is important to include the water molecule in the analysis. Figure Hydrogen bonding networks at the active sites of both CDK5/R-roscotivine (light grey) and CDK2/R-roscovitine (black).     

A Vertebrate-Specific Chp-PAK-PIX Pathway Maintains E-Cadherin at Adherens Junctions during Zebrafish Epiboly

Background

In early vertebrate development, embryonic tissues modulate cell adhesiveness and acto-myosin contractility to correctly orchestrate the complex processes of gastrulation. E-cadherin (E-cadh) is the earliest expressed cadherin and is needed in the mesendodermal progenitors for efficient migration [1], [2]. Regulatory mechanisms involving directed E-cadh trafficking have been invoked downstream of Wnt11/5 signaling [3]. This non-canonical Wnt pathway regulates RhoA-ROK/DAAM1 to control the acto-myosin network. However, in this context nothing is known of the intracellular signals that participate in the correct localization of E-cadh, other than a need for Rab5c signaling [3].

Methodology/Principal Findings

By studying loss of Chp induced by morpholino-oligonucleotide injection in zebrafish, we find that the vertebrate atypical Rho-GTPase Chp is essential for the proper disposition of cells in the early embryo. The underlying defect is not leading edge F-actin assembly (prominent in the cells of the envelope layer), but rather the failure to localize E-cadh and β-catenin at the adherens junctions. Loss of Chp results in delayed epiboly that can be rescued by mRNA co-injection, and phenocopies zebrafish E-cadh mutants [4], [5]. This new signaling pathway involves activation of an effector kinase PAK, and involvement of the adaptor PAK-interacting exchange factor PIX. Loss of signaling by any of the three components results in similar underlying defects, which is most prominent in the epithelial-like envelope layer.

Conclusions/Significance

Our current study uncovers a developmental pathway involving Chp/PAK/PIX signaling, which helps co-ordinate E-cadh disposition to promote proper cell adhesiveness, and coordinate movements of the three major cell layers in epiboly. Our data shows that without Chp signaling, E-cadh shifts to intracellular vesicles rather than the adhesive contacts needed for directed cell movement. These events may mirror the requirement for PAK2 signaling essential for the proper formation of the blood-brain barrier [6], [7].     

Molecular and morphological characterization of neural tube defects in embryos of diabetic Swiss Albino mice

BACKGROUND AND RESULTS: Embryos from diabetic mice exhibit several forms of neural tube defects, including non-closure of the neural tube. In the present study, embryos collected at embryonic day 11.5 from diabetic pregnancies displayed open neural tube with architectural disruption of the surrounding tissues. The percentage of proliferating cells was found to be increased in the dorsal and ventral domains of the spinal neural tube of embryos from diabetic mice, indicating a defect in the proliferation index. We have analyzed the development of various cell types, including motoneurons, interneurons, oligodendrocytes and migrating neurons, as well as radial glial cells in the open neural tube using specific molecular markers. Immunofluorescence results revealed a significantly reduced number of Pax2+ interneurons and increased number of Isl-1+ motoneurons, as well as Olig2+ oligodendrocytes in the neural tube of embryos from diabetic mice as compared to controls. In addition, these embryos exhibited a decreased number of doublecortin positive migrating neurons and Glast/Blbp positive radial glial cells with shortened processes in the neural tube. Expression levels of several developmental control genes involved in the generation of different neuronal cell types (such as Shh, Ngn, Ngn2, Ascl1) were also found to be altered in the neural tube of embryos from diabetic mice. CONCLUSIONS: Overall, the open neural tube in embryos of diabetic mice exhibits defects in the specification of different cell types, including motoneurons and interneurons, as well as glial cells along the dorsoventral axis of the developing spinal cord. Although these defects are associated with altered expression of several development control genes, the exact mechanisms by which maternal diabetes contributes to these changes remain to be investigated.     

Male-limited evolution suggests no extant intralocus sexual conflict over the sexually dimorphic cuticular hydrocarbons of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

Sexually dimorphic traits are likely to have evolved through sexually antagonistic selection. However, recent empirical data suggest that intralocus sexual conflict often persists, even when traits have diverged between males and females. This implies that evolved dimorphism is often incomplete in resolving intralocus conflict, providing a mechanism for the maintenance of genetic variance in fitness-related traits. We used experimental evolution in Drosophila melanogaster to directly test for ongoing conflict over a suite of sexually dimorphic cuticular hydrocarbons (CHCs) that are likely targets of sex-specific selection. Using a set of experimental populations in which the transmission of genetic material had been restricted to males for 82 generations, we show that CHCs did not evolve, providing experimental evidence for the absence of current intralocus sexual conflict over these traits. The absence of ongoing conflict could indicate that CHCs have never been the target of sexually antagonistic selection, although this would require the existing dimorphism to have evolved via completely sexlinked mutations or as a result of former, but now absent, pleiotropic effects of the underlying loci on another trait under sexually antagonistic selection. An alternative interpretation, and which we believe to be more likely, is that the extensive CHC sexual dimorphism is the result of past intralocus sexual conflict that has been fully resolved, implying that these traits have evolved genetic independence between the sexes and that genetic variation in them is therefore maintained by alternative mechanisms. This latter interpretation is consistent with the known roles of CHCs in sexual communication in this species and with previous studies suggesting the genetic independence of CHCs between males and females. Nevertheless, direct estimates of sexually antagonistic selection will be important to fully resolve these alternatives.