Fully immunocompetent CD8+ T lymphocytes are present in autologous haematopoietic stem cell transplantation recipients despite an ineffectual T-helper response

Background

Reduced CD4 T lymphocytes counts can be observed in HIV infection and in patients undergoing autologous haematopoietic stem cell transplantation (ASCT). Nevertheless, whereas opportunistic infections (OI) are frequent in HIV-infected individuals with low cell counts, OI are uncommon in ASCT patients.

Methodology/Principal Findings

To verify whether this observation could be secondary to intrinsic HIV-correlated T cell defects, we performed in-depth immunologic analyses in 10 patients with comparable CD4 counts in whom lymphopenia was secondary either to HIV-infection or ASCT-associated immunosuppressive therapy and compared them to age-matched healthy subjects. Results showed the presence of profound alterations in CD4+ T lymphocytes in both groups of patients with respect to healthy controls. Thus, a low percentage of CCR7+ CD4+ T cells and a compensative expansion of CD45RA−CCR7− CD4+ T cells, a reduced IL-2/IFN-γ cytokine production and impaired recall antigens-specific proliferative responses were detected both in ASCT and HIV patients. In stark contrast, profound differences were detected in CD8+ T-cells between the two groups of patients. Thus, mature CD8+ T cell prevailed in ASCT patients in whom significantly lower CD45RA−CCR7− cells, higher CD45RA+CCR7− CD8+ cells, and an expansion of CCR7+CD8+ cells was detected; this resulted in higher IFN-γ +/TNFα production and granzyme CD8+ expression. The presence of strong CD8 T cells mediated immune responses justifies the more favorable clinical outcome of ASCT compared to HIV patients.

Conclusion/Significance

These results indicate that CD8 T cells maturation and functions can be observed even in the face of a profound impairment of CD4+ T lymphocytes in ASCT but not in HIV patients. Primary HIV-associated CD8 defects or an imprinting by an intact CD4 T cell system in ASCT could justify these results.     

Prion protein amino acid determinants of differential susceptibility and molecular feature of prion strains in mice and voles

The bank vole is a rodent susceptible to different prion strains from humans and various animal species. We analyzed the transmission features of different prions in a panel of seven rodent species which showed various degrees of phylogenetic affinity and specific prion protein (PrP) sequence divergences in order to investigate the basis of vole susceptibility in comparison to other rodent models. At first, we found a differential susceptibility of bank and field voles compared to C57Bl/6 and wood mice. Voles showed high susceptibility to sheep scrapie but were resistant to bovine spongiform encephalopathy, whereas C57Bl/6 and wood mice displayed opposite features. Infection with mouse-adapted scrapie 139A was faster in voles than in C57Bl/6 and wood mice. Moreover, a glycoprofile change was observed in voles, which was reverted upon back passage to mice. All strains replicated much faster in voles than in mice after adapting to the new species. PrP sequence comparison indicated a correlation between the transmission patterns and amino acids at positions 154 and 169 (Y and S in mice, N and N in voles). This correlation was confirmed when inoculating three additional rodent species: gerbils, spiny mice and oldfield mice with sheep scrapie and 139A. These rodents were chosen because oldfield mice do have the 154N and 169N substitutions, whereas gerbil and spiny mice do not have them. Our results suggest that PrP residues 154 and 169 drive the susceptibility, molecular phenotype and replication rate of prion strains in rodents. This might have implications for the assessment of host range and molecular traceability of prion strains, as well as for the development of improved animal models for prion diseases.     

Autophagy and amyotrophic lateral sclerosis: The multiple roles of lithium

In a pilot clinical study that we recently published we found that lithium administration slows the progression of Amyotrophic Lateral Sclerosis (ALS) in human patients. This clinical study was published in addition with basic (in vitro) and pre-clinical (in vivo) data demonstrating a defect of autophagy as a final common pathway in the genesis of ALS. In fact, lithium was used as an autophagy inducer. In detailing the protective effects of lithium we found for the first time that this drug stimulates the biogenesis of mitochondria in the central nervous system and, uniquely in the spinal cord, it induces neuronogenesis and neuronal differentiation. In particular, the effects induced by lithium can be summarized as follows: (i) the removal of altered mitochondria and protein aggregates; (ii) the biogenesis of well-structured mitochondria; (iii) the suppression of glial proliferation; (iv) the differentiation of newly formed neurons in the spinal cord towards a specific phenotype. In this addendum we focus on defective autophagy as a "leit motif" in ALS and the old and novel features of lithium which bridge autophagy activation to concomitant effects that may be useful for the treatment of a variety of neurodegenerative disorders. In particular, the biogenesis of mitochondria and the increase of calbindin D 28K-positive neurons, which are likely to support powerful neuroprotection towards autophagy failure, mitochondriopathy and neuronal loss in the spinal cord.     

Hierarchically structured scleractinian coral biocrystals

Microscopic (AFM and FESEM) observations show that scleractinian coral biomineral fibers in extant Desmophyllum and Favia, and fossil Jurassic Isastrea are composed of nanocrystalline grains of about 30-100 nm in size. In contrast to these findings, SR diffraction data on the same coral materials exhibit narrow Bragg peaks suggesting much larger crystallite size. These seemingly contradicting results of microscopic and diffraction studies are reconciled within a new, minute-scale model of scleractinian biomineral fibers. In this model, nanocrystalline aragonite units are interconnected by mineral bridges and form aggregates usually larger than 200 nm. Most likely, the size of the aggregates is resulting from physiological biomineralization cycles that control cellular secretion of ions and biopolymeric species. Intercalation of biopolymers into crystal lattice may influence consistently several structural parameters of the scleractinian coral bio-aragonite in all studied samples: (i) the lattice parameters and internal strains of the bio-aragonite are larger than in mineral aragonite, (ii) lattice parameter elongations and internal strains reveal directional anisotropy with respect to crystallographic axes.     

The Yku70-Yku80 complex contributes to regulate double-strand break processing and checkpoint activation during the cell cycle

DNA double-strand breaks (DSBs) are repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). HR requires 5' DSB end degradation that occurs in the presence of cyclin-dependent kinase (CDK) activity. Here, we show that a lack of any of the NHEJ proteins Yku (Yku70-Yku80), Lif1 or DNA ligase IV (Dnl4) increases 5' DSB end degradation in G1 phase, with ykuDelta cells showing the strongest effect. This increase depends on MRX, the recruitment of which at DSBs is enhanced in ykuDelta G1 cells. DSB processing in G2 is not influenced by the absence of Yku, but it is delayed by Yku overproduction, which also decreases MRX loading on DSBs. Moreover, DSB resection in ykuDelta cells occurs independently of CDK activity, suggesting that it might be promoted by CDK-dependent inhibition of Yku.     

A SNP transferability survey within the genus <Emphasis Type="Italic">Vitis</Emphasis>

Background  

Efforts to sequence the genomes of different organisms continue to increase. The DNA sequence is usually decoded for one individual and its application is for the whole species. The recent sequencing of the highly heterozygous Vitis vinifera L. cultivar Pinot Noir (clone ENTAV 115) genome gave rise to several thousand polymorphisms and offers a good model to study the transferability of its degree of polymorphism to other individuals of the same species and within the genus.     

SNP high-throughput screening in grapevine using the SNPlex™ genotyping system

Background

Until recently, only a small number of low- and mid-throughput methods have been used for single nucleotide polymorphism (SNP) discovery and genotyping in grapevine (Vitis vinifera L.). However, following completion of the sequence of the highly heterozygous genome of Pinot Noir, it has been possible to identify millions of electronic SNPs (eSNPs) thus providing a valuable source for high-throughput genotyping methods.

Results

Herein we report the first application of the SNPlex? genotyping system in grapevine aiming at the anchoring of an eukaryotic genome. This approach combines robust SNP detection with automated assay readout and data analysis. 813 candidate eSNPs were developed from non-repetitive contigs of the assembled genome of Pinot Noir and tested in 90 progeny of Syrah × Pinot Noir cross. 563 new SNP-based markers were obtained and mapped. The efficiency rate of 69% was enhanced to 80% when multiple displacement amplification (MDA) methods were used for preparation of genomic DNA for the SNPlex assay.

Conclusion

Unlike other SNP genotyping methods used to investigate thousands of SNPs in a few genotypes, or a few SNPs in around a thousand genotypes, the SNPlex genotyping system represents a good compromise to investigate several hundred SNPs in a hundred or more samples simultaneously. Therefore, the use of the SNPlex assay, coupled with whole genome amplification (WGA), is a good solution for future applications in well-equipped laboratories.     

Phase I dynamics of cardiac output, systemic O2 delivery, and lung O2 uptake at exercise onset in men in acute normobaric hypoxia

We tested the hypothesis that vagal withdrawal plays a role in the rapid (phase I) cardiopulmonary response to exercise. To this aim, in five men (24.6+/-3.4 yr, 82.1+/-13.7 kg, maximal aerobic power 330+/-67 W), we determined beat-by-beat cardiac output (Q), oxygen delivery (QaO2), and breath-by-breath lung oxygen uptake (VO2) at light exercise (50 and 100 W) in normoxia and acute hypoxia (fraction of inspired O2=0.11), because the latter reduces resting vagal activity. We computed Q from stroke volume (Qst, by model flow) and heart rate (fH, electrocardiography), and QaO2 from Q and arterial O2 concentration. Double exponentials were fitted to the data. In hypoxia compared with normoxia, steady-state fH and Q were higher, and Qst and VO2 were unchanged. QaO2 was unchanged at rest and lower at exercise. During transients, amplitude of phase I (A1) for VO2 was unchanged. For fH, Q and QaO2, A1 was lower. Phase I time constant (tau1) for QaO2 and VO2 was unchanged. The same was the case for Q at 100 W and for fH at 50 W. Qst kinetics were unaffected. In conclusion, the results do not fully support the hypothesis that vagal withdrawal determines phase I, because it was not completely suppressed. Although we can attribute the decrease in A1 of fH to a diminished degree of vagal withdrawal in hypoxia, this is not so for Qst. Thus the dual origin of the phase I of Q and QaO2, neural (vagal) and mechanical (venous return increase by muscle pump action), would rather be confirmed.