Molecular mechanisms of ATP secretion during immunogenic cell death

The immunogenic demise of cancer cells can be induced by various chemotherapeutics, such as anthracyclines and oxaliplatin, and provokes an immune response against tumor-associated antigens. Thus, immunogenic cell death (ICD)-inducing antineoplastic agents stimulate a tumor-specific immune response that determines the long-term success of therapy. The release of ATP from dying cells constitutes one of the three major hallmarks of ICD and occurs independently of the two others, namely, the pre-apoptotic exposure of calreticulin on the cell surface and the postmortem release of high-mobility group box 1 (HMBG1) into the extracellular space. Pre-mortem autophagy is known to be required for the ICD-associated secretion of ATP, implying that autophagy-deficient cancer cells fail to elicit therapy-relevant immune responses in vivo. However, the precise molecular mechanisms whereby ATP is actively secreted in the course of ICD remain elusive. Using a combination of pharmacological screens, silencing experiments and techniques to monitor the subcellular localization of ATP, we show here that, in response to ICD inducers, ATP redistributes from lysosomes to autolysosomes and is secreted by a mechanism that requires the lysosomal protein LAMP1, which translocates to the plasma membrane in a strictly caspase-dependent manner. The secretion of ATP additionally involves the caspase-dependent activation of Rho-associated, coiled-coil containing protein kinase 1 (ROCK1)-mediated, myosin II-dependent cellular blebbing, as well as the opening of pannexin 1 (PANX1) channels, which is also triggered by caspases. Of note, although autophagy and LAMP1 fail to influence PANX1 channel opening, PANX1 is required for the ICD-associated translocation of LAMP1 to the plasma membrane. Altogether, these findings suggest that caspase- and PANX1-dependent lysosomal exocytosis has an essential role in ATP release as triggered by immunogenic chemotherapy.     

Correlation of Y-chromosome multiple segmental deletions and chromosomal anomalies in non-obstructive azoospermic males from northeastern China

We investigated the frequency and types of Y-chromosome microdeletions and chromosomal anomalies in non-obstructive azoospermic and severely oligozoospermic infertile males in northeastern China. The sample consisted of 519 infertile males (456 azoospermic, 63 severely oligozoospermic). PCR assays for Y-chromosome microdeletions and chromosome analysis were performed on all patients and controls. Array-comparative genomic hybridization was performed for three patients with chromosomal anomalies. Fifty-nine of 519 patients (11.37%) had Y-chromosome microdeletions. Microdeletions were found in 11.18% (51/456) of the non-obstructive azoospermic patients and in 12.7% (8/63) of the severely oligozoospermic patients. Eleven of 51 non-obstructive azoospermic patients with Y-chromosome microdeletions had multiple segmental deletions in the AZFb+c regions; four of these patients had chromosomal anomalies. Our sample from northeastern China had a higher frequency of microdeletions among severely oligozoospermic than among non-obstructive azoospermic males.     

Derivatives of L-Adenosine and L-Guanosine as Substrates for Human Deoxycytidine Kinase

Abstract

A series of analogues of L-adenosine and of L-guanosine, including ß-L-dA, ß-L-Ado, ß-L-araA, and ß-L-dG, have been shown to be substrates of human deoxycytidine kinase thus demonstrating the complete lack of enantioselectivity of this enzyme.     

Characterization of Prolamins from Meadow Grasses: Homology with those of Wheat, Barley and Rye

Prolamin fractions were extracted from seeds of five speciesof temperate meadow grasses. SDS-PAGE showed the presence ofpolypeptidcs with M_rs of 20–30000 in Phieum pratense andDactylis glomerata, and between 30000 and 65 000 in Lolium perenneand in two species of Festuca (F. rubra and F. arundinacea).The fractions had broadly similar amino acid compositions withhigh glutamate+glutamine (29 to 35 mol %) and phenylalaninc(8 to 10 mol %), but there was some variation in the contentsof prolinc (10 to 23 mol %) and several other amino acids includinglysine (0.3 to 1.9 mol %). Automated Edman degradation of twogel filtration fractions from L perenne and one fraction eachfrom the other four species showed single major N.terminal aminoacid sequences. These were homologous with each other, and withthe -typc prolamins of wheat, barley and rye. Key words: Prolamins, meadow grasses, SDS-PAGE     

Abl deregulates Cdk5 kinase activity and subcellular localization in Drosophila neurodegeneration

Although Abl functions in mature neurons, work to date has not addressed Abl's role on Cdk5 in neurodegeneration. We found that beta-amyloid (Abeta42) initiated Abl kinase activity and that blockade of Abl kinase rescued both Drosophila and mammalian neuronal cells from cell death. We also found activated Abl kinase to be necessary for the binding, activation, and translocalization of Cdk5 in Drosophila neuronal cells. Conversion of p35 into p25 was not observed in Abeta42-triggered Drosophila neurodegeneration, suggesting that Cdk5 activation and protein translocalization can be p25-independent. Our genetic studies also showed that abl mutations repressed Abeta42-induced Cdk5 activity and neurodegeneration in Drosophila eyes. Although Abeta42 induced conversion of p35 to p25 in mammalian cells, it did not sufficiently induce Cdk5 activation when c-Abl kinase activity was suppressed. Therefore, we propose that Abl and p35/p25 cooperate in promoting Cdk5-pY15, which deregulates Cdk5 activity and subcellular localization in Abeta42-triggered neurodegeneration.     

Relationship between formation of the femoral bicondylar angle and trochlear shape: independence of diaphyseal and epiphyseal growth

During hominin evolution, an increase in the femoral bicondylar angle was the initial change that led to selection for protuberance of the lateral trochlear lip and the elliptical profile of the lateral condyle. No correlation is found during ontogeny between the degree of femoral obliquity and of the prominence of the lateral trochlear lip. Might there be a relationship with the elliptical profile of the lateral condyle? On intact femoral diaphyses of juvenile humans and great apes, we compared the anteroposterior length of the lateral and medial sides of the distal metaphysis. The two diaphyseal pillars remain equal during postnatal growth in great apes, while the growth of the lateral pillar far exceeds that of the medial pillar in humans. Increase in bicondylar angle is correlated with disproportionate anteroposterior lengthening of the lateral pillar. The increased anteroposterior length of the lateral side of the metaphysis would contribute to increasing the radius of the curvature of the lateral condyle, but not to the projection of the lateral trochlear lip. The similar neonatal and adult femoro‐patellar joint shape in humans prompted an assessment of the similarity during growth of the entire neonatal and adult epiphyses. We showed that the entire epiphysis undergoes drastic changes in proportions during postnatal growth. Finally, we emphasize the need to distinguish the cartilaginous phenotype and the ossified phenotype of the distal femoral epiphysis (and of any epiphysis) during postnatal growth. This crucial distinction applies to most postcranial bones, for they almost all develop following the process of endochondral ossification. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.     

Influence of season and host age on wild boar parasites in Corsica using indicator species analysis

The indicator value (Ind Val) method which combines measures of fidelity and specificity has been used in a study on wild boar parasites in Corsica during 2001-2003. Because of its resilience to changes in abundance, IndVal is a particularly effective tool for ecological bioindication. The Ind Val method showed how season can influence the occurrence of parasite species in the wild boar, and also identified parasites as bioindicators relative to host age. The randomization test identified five parasite species having a significant indicator value for the season (the ticks, Hyalomma aegyptium and Rhipicephalus sanguineus, the louse, Haematopinus suis and the nematodes Globocephalus urosubulatus and Ascaris suum and two indicator species of an age class (the nematodes G. urosubulatus and Metastrongylus sp.). Data on species composition and infection levels would help improve the monitoring and management of parasitism in Suidae populations.