Pseudotyped recombinant adeno-associated viral vectors mediate efficient gene transfer into primary human CD34+ peripheral blood progenitor cells

Background and aimsBecause of their pluripotency, human CD34⁺ peripheral blood progenitor cells (PBPC) are targets of interest for the treatment of many acquired and inherited disorders using gene therapeutic approaches. Unfortunately, most current vector systems lack either sufficient transduction efficiency or an appropriate safety profile. Standard single-stranded recombinant adeno-associated virus 2 (AAV2)-based vectors offer an advantageous safety profile, yet lack the required efficiency in human PBPC.MethodsA panel of pseudotyped AAV vectors (designated AAV2/x, containing the vector genome of serotype 2 and capsid of serotype x, AAV2/1–AAV2/6) was screened on primary human granulocyte–colony-stimulating factor (G-CSF)-mobilized CD34⁺ PBPC to determine their gene transfer efficacy. Additionally, double-stranded self-complementary AAV (dsAAV) were used to determine possible second-strand synthesis limitations.ResultsAAV2/6 vectors proved to be the most efficient [12.8% (1.8–25.4%) transgene-expressing PBPC after a single transduction], being significantly more efficient (all P < 0.005) than the other vectors [AAV2/2, 2.0% (0.2–7.3%); AAV2/1, 1.3% (0.1–2.9%); others, <; 1% transgene-expressing PBPC]. In addition, the relevance of the single-to-double-strand conversion block in transduction of human PBPC could be shown using pseudotyped dsAAV vectors: for dsAAV2/2 [9.3% (8.3–20.3%); P < 0.001] and dsAAV2/6 [37.7% (23.6–61.0%); P < 0.001) significantly more PBPC expressed the transgene compared with their single-stranded counterparts; for dsAAV2/1, no significant increase could be observed.ConclusionsWe have shown that clinically relevant transduction efficiency levels using AAV-based vectors in human CD34⁺ PBPC are feasible, thereby offering an efficient alternative vector system for gene transfer into this important target cell population.     

Past attacks influence host selection by the solitary bark beetle Dendroctonus micans

1. A spatio‐temporal study of host selection and local spread of a solitary bark beetle attacking live spruce Dendroctonus micans (Kugelann) was carried out using a combination of standard statistical methods, geostatistical analyses, and modelling. The study was based on data from three plots (150–300 trees, 0.3–1 ha) from 1978 to 1993. All trees were mapped and successful and abortive bark‐beetle attacks on each tree were counted annually. Because the attacked trees usually survived, temporal attack patterns as well as spatial patterns could be analysed. 2. The distribution of successful insect attacks on the trees was slightly aggregative, indicating some degree of choice rather than totally random establishment. 3. The level of yearly individual attacks per tree was very stable, suggesting that D. micans usually leave the host in which they develop. 4. The attacked trees were distributed randomly in the plots; at the study's spatial scale, the insects dispersed freely throughout the plot (no spatial dependence). 5. On the other hand, time dependence was strong; some trees were attacked repeatedly while others were left untouched. 6. Among a choice of scenarios (random attack, fixed variability in individual host susceptibility, induced host susceptibility following random attack), the best fit was obtained with the model involving induced individual host susceptibility. This type of relation to the host tree contrasts strongly with patterns generally described in host–plant relationships (including gregarious, tree‐killing bark beetles), where local herbivore damage results in induced resistance. 7. These results suggest that the first attacks in a new stand are made at random, that all or most of the beetles emerging from a tree disperse and resample the stand, and that they settle preferentially on trees that were colonised successfully by previous generations.     

Cutting proteins within lipid bilayers: rhomboid structure and mechanism

Rhomboids were only discovered to be novel proteases in 2001, but progress on understanding this newest family of intramembrane proteases has been rapid. They are now the best characterized of these rather mysterious enzymes that cleave transmembrane domains within the lipid bilayer. In particular, the biochemical analysis of solubilized rhomboids and, most recently, a flurry of high-resolution crystal structures, have led to real insight into their enzymology. Long-standing questions about how it is possible for a water-requiring proteolytic reaction to occur in the lipid bilayer are now answered for the rhomboids. Intramembrane proteases, which control many medically important biological processes, have made the transition from rather heretical outsiders to novel enzymes that are becoming well understood.     

Wnt-3a utilizes a novel low dose and rapid pathway that does not require casein kinase 1-mediated phosphorylation of Dvl to activate beta-catenin

The current view of canonical Wnt signalling is that following Wnt binding to its receptors (Frizzled-Lrp5/6), dishevelled (Dvl) becomes hyperphosphorylated, and the signal is transduced to the APC-GSK3beta-axin-beta-catenin multiprotein complex, which subsequently dissociates. As a result beta-catenin is not phosphorylated, escapes proteosomal degradation and activates its target genes after translocation to the nucleus. Here, we analyzed the importance of the Wnt-3a-induced phosphorylation and shift in electrophoretic migration of Dvl (PS-Dvl) for the activation of beta-catenin. Analysis of Wnt-3a time- and dose-responses in a dopaminergic cell line showed that beta-catenin is activated rapidly (within minutes) and at a low dose of Wnt-3a (1 ng/ml). Surprisingly, PS-Dvl appeared only after 30 min and at greater doses (> or =20 ng/ml) of Wnt-3a. Moreover, we found that a casein kinase 1 inhibitor (D4476) or siRNA for casein kinase 1 delta/epsilon (CK1delta/epsilon) blocked the Wnt-3a-induced PS-Dvl. Interestingly, CK1 inhibition or siRNA for CK1delta/epsilon did not ablate the activation of beta-catenin by Wnt-3a, indicating that there is a PS-Dvl-independent path to activate beta-catenin. The increase in beta-catenin activation by Wnt-3a (PS-Dvl-dependent or -independent) were blocked by Dickkopf1 (Dkk1), suggesting that the effect of Wnt-3a is in both cases mediated by Lrp5/6 receptors. Thus, our results show that Wnt-3a rapidly induce a partial activation of beta-catenin in the absence of PS-Dvl at low doses, while at high doses induce a full activation of beta-catenin in a PS-Dvl-dependent manner.     

Dentinogenesis imperfecta

Dentinogenesis imperfecta is a congenital dentin dysplasia that occurs either isolated or associated with a genetic disorder known as osteogenesis imperfecta. Dentinogenesis imperfecta is inherited in an autosomal dominant pattern. Clinically the teeth color of both dentitions varies from brown to a translucent gray with an opalescent sheen. Shields et al. (1973) proposed a classification of Dentinogenesis imperfecta into three types: type I, associated with osteogenesis imperfecta; type II, hereditary opalescent dentin; type III Brandywine-type. The phenotypes of Dentinogenesis imperfecta are described in regard to their genetic defects, pathology, radiology and histopathology as well as their dental treatment.     

Antiamnesic and Antioxidants Effects of Ferulago angulata Essential Oil Against Scopolamine-Induced Memory Impairment in Laboratory Rats

Neurochemical Research - Ferulago angulata (Apiaceae) is a shrub indigenous to western Iran, Turkey and Iraq. In traditional medicine, F. angulata is recommended for treating digestive pains,...     

Room temperature crystal structure of the fast switching M159T mutant of the fluorescent protein dronpa

The fluorescent protein Dronpa undergoes reversible photoswitching reactions between the bright “on” and dark “off” states via photoisomerization and proton transfer reactions. We report the room temperature crystal structure of the fast switching Met159Thr mutant of Dronpa at 2.0‐Å resolution in the bright on state. Structural differences with the wild type include shifted backbone positions of strand β8 containing Thr159 as well as an altered A‐C dimer interface involving strands β7, β8, β10, and β11. The Met159Thr mutation increases the cavity volume for the p‐hydroxybenzylidene‐imidazolinone chromophore as a result of both the side chain difference and the backbone positional differences. Proteins 2015; 83:397–402. © 2014 Wiley Periodicals, Inc.     

Allostery mediates ligand binding to WWOX tumor suppressor via a conformational switch

While being devoid of the ability to recognize ligands itself, the WW2 domain is believed to aid ligand binding to the WW1 domain in the context of a WW1–WW2 tandem module of WW domain‐containing oxidoreductase (WWOX) tumor suppressor. In an effort to test the generality of this hypothesis, we have undertaken here a detailed biophysical analysis of the binding of WW domains of WWOX alone and in the context of the WW1–WW2 tandem module to an array of putative proline‐proline‐x–tyrosine (PPXY) ligands. Our data show that while the WW1 domain of WWOX binds to all ligands in a physiologically relevant manner, the WW2 domain does not. Moreover, ligand binding to the WW1 domain in the context of the WW1–WW2 tandem module is two‐to‐three‐fold stronger than when treated alone. We also provide evidence that the WW domains within the WW1–WW2 tandem module physically associate so as to adopt a fixed spatial orientation relative to each other. Of particular note is the observation that the physical association of the WW2 domain with WW1 blocks access to ligands. Consequently, ligand binding to the WW1 domain not only results in the displacement of the WW2 lid but also disrupts the physical association of WW domains in the liganded conformation. Taken together, our study underscores a key role of allosteric communication in the ability of the WW2 orphan domain to chaperone physiological action of the WW1 domain within the context of the WW1–WW2 tandem module of WWOX. Copyright © 2015 John Wiley & Sons, Ltd.