Modulation of Mutant Huntingtin N-Terminal Cleavage and Its Effect on Aggregation and Cell Death

Huntington’s disease (HD) is a neurodegenerative disorder caused by a polyglutamine expansion near the N-terminus of huntingtin. A neuropathological hallmark of Huntington’s disease is the presence of intracellular aggregates composed of mutant huntingtin N-terminal fragments in human postmortem brain, animal models, and cell culture models. It has been found that N-terminal fragments of the mutant huntingtin protein are more toxic than the full-length protein. Therefore, proteolytic processing of mutant huntingtin may play a key event in the pathogenesis of HD. Here, we present evidence that the region in huntingtin covering amino acids 116 to 125 is critical for N-terminal proteolytic processing. Within this region, we have identified mutations that either strongly reduce or enhance N-terminal cleavage. We took advantage of this effect and demonstrate that the mutation Δ121–122 within the putative cleavage region enhances N-terminal cleavage of huntingtin and the aggregation of N-terminal fragments. Furthermore, this particular deletion increased the activation of apoptotic processes and decreased neuronal cell viability. Our data indicate that the N-terminal proteolytic processing of mutant huntingtin can be modulated with an effect on aggregation and cell death rate

Schwarzes Gold und grüne Ambitionen: Ressourcenpolitik in den Andenländern

Der Ausgang der im Juni 2011 in Peru anstehenden Präsidentschaftswahlen wird auch über die zukünftige Ausrichtung der Ressourcenpolitik des Landes entscheiden. Eine Stärkung der Rolle des Staates in der ressourcenbasierten Volkswirtschaft würde dem Vorbild der Politiken in Bolivien, Ecuador und Venezuela folgen. Die steigende globale Nachfrage nach Erdöl und Erdgas macht deren Ausbeutung auch in den rohstoffreichen Andenländern attraktiver. Die linksgerichteten Regierungen der Region vertreten rhetorisch eine "neue" Ressourcenpolitik, die dazu beitragen soll, die Ressourcenausbeutung ökologisch und sozial verträglicher zu gestalten sowie mehr Verteilungsgerechtigkeit herzustellen. Anspruch und Realität klaffen jedoch weit auseinander. In Bolivien, Ecuador und Venezuela ist auf dem Papier mit der Veränderung der Staats- und Wirtschaftsmodelle auch eine Neuausrichtung der Ressourcenpolitiken einhergegangen. In der Praxis wurde trotz der gestärkten Rolle des Staates die einseitige Ausrichtung auf den Export von Primärgütern weiter vertieft. Ressourcen- und Umweltkonflikte haben sich in den vergangenen Jahren im Andenraum vermehrt und zugespitzt. Die peruanische Regierung begegnete diesen besonders repressiv. In Bolivien und Ecuador ermahnen Protestbewegungen dazu, die in den neuen Verfassungen deutlich ausgeweiteten sozialen Menschen- und Umweltrechte sowie das neue Entwicklungsmodell des Buen Vivir in die Tat umzusetzen. Der verstärkte globale Wettbewerb um fossile Brennstoffe und das Interesse nationaler Regierungen an kurzfristigen Gewinnen zur Umsetzung ehrgeiziger Sozialprogramme schränken die Aussichten auf eine Abkehr von der hohen Ressourcenabhängigkeit der Andenländer stark ein

Functional consequences of genetic polymorphisms in the NKG2D receptor signaling pathway and putative gene interactions

NKG2D (NK group 2, member D) is an activating natural killer (NK) receptor, which is expressed on NK and CD8+ T cells. On NK cells, NKG2D elicits cytotoxicity and release of cytokines. On CD8+ T cells, it functions as a co-stimulatory molecule. The receptor recognizes several ligands including the major histocompatibility complex (MHC) class I chain-related molecules A (MICA) and B (MICB) as well as the UL16-binding proteins (ULBP). The diversity of NKG2D ligands is further increased by a high degree of genetic variability of the ligands. Recently, an amino acid exchange from valine to methionine at position 129 in MICA has been found to be associated with the outcome of allogeneic hematopoietic stem cell transplantation (HSCT), and the functional consequences of this specific genetic variation have been elucidated. The clinical associations found after HSCT were explainable by the functional differences of the MICA-129 variants. Herein, we discuss how the genetic polymorphisms of NKG2D ligands and NKG2D itself interact and may affect the outcome of HSCT and the susceptibility to other diseases, which have been associated with polymorphisms in the NKG2D signaling pathway

A single polyploidization event at the origin of the tetraploid genome of Coffea arabica is responsible for the extremely low genetic variation in wild and cultivated germplasm

The genome of the allotetraploid species Coffea arabica L. was sequenced to assemble independently the two component subgenomes (putatively deriving from C. canephora and C. eugenioides) and to perform a genome-wide analysis of the genetic diversity in cultivated coffee germplasm and in wild populations growing in the center of origin of the species. We assembled a total length of 1.536 Gbp, 444 Mb and 527 Mb of which were assigned to the canephora and eugenioides subgenomes, respectively, and predicted 46,562 gene models, 21,254 and 22,888 of which were assigned to the canephora and to the eugeniodes subgenome, respectively. Through a genome-wide SNP genotyping of 736 C. arabica accessions, we analyzed the genetic diversity in the species and its relationship with geographic distribution and historical records. We observed a weak population structure due to low-frequency derived alleles and highly negative values of Taijma's D, suggesting a recent and severe bottleneck, most likely resulting from a single event of polyploidization, not only for the cultivated germplasm but also for the entire species. This conclusion is strongly supported by forward simulations of mutation accumulation. However, PCA revealed a cline of genetic diversity reflecting a west-to-east geographical distribution from the center of origin in East Africa to the Arabian Peninsula. The extremely low levels of variation observed in the species, as a consequence of the polyploidization event, make the exploitation of diversity within the species for breeding purposes less interesting than in most crop species and stress the need for introgression of new variability from the diploid progenitors

Atrophin-1, the Dentato-Rubral and Pallido-Luysian Atrophy Gene Product, Interacts with Eto/Mtg8 in the Nuclear Matrix and Represses Transcription

Dentato-rubral and pallido-luysian atrophy (DRPLA) is one of the family of neurodegenerative diseases caused by expansion of a polyglutamine tract. The drpla gene product, atrophin-1, is widely expressed, has no known function or activity, and is found in both the nuclear and cytoplasmic compartments of neurons. Truncated fragments of atrophin-1 accumulate in neuronal nuclei in a transgenic mouse model of DRPLA, and may underlie the disease phenotype

Health outcomes in offspring born to survivors of childhood cancers following assisted reproductive technologies

Purpose: An increasing number of childhood cancer survivors are using assisted reproductive technologies (ART) to overcome treatment-related fertility impairment. We report perinatal and health outcomes of offspring born to survivors following ART. Methods: The FeCt Multicenter Offspring Study surveyed the health of offspring of childhood cancer survivors. Health outcomes in offspring born to survivors following ART (n = 57, 4.6%) or after spontaneous conception (n = 1182) were assessed in the German cohort (n = 1239) using bivariate analysis. Findings were put into the context of the general German population by health outcome assessment in 1:1 matched-pair analysis (n = 2478). Results: Nearly twice the survivors used ART compared with numbers reported for the German general population (4.6% vs. 2.6%). Successful pregnancies were achieved after a median of two cycles, mainly using non-cryopreserved oocytes/sperm. Multiple sibling births (p < 0.001, 28.1% vs. 3.0%) and low birth weight (p = 0.008; OR = 2.659, 95% CI = 1.258-5.621) occurred significantly more often in offspring born to survivors who utilized ART than spontaneously conceived children, whereas similar percentages were born preterm or too small for their gestational age. ART did not increase the prevalence of childhood cancer or congenital malformations in offspring born to survivors. Conclusion: ART use by childhood cancer survivors was successful with both fresh and cryopreserved oocytes/sperm, and did not influence perinatal health or health outcomes when known confounders were taken into account. Implications for cancer survivors: Oncofertility is an important component of patient care. Our study implicates that the utilization of ART by adult survivors of childhood cancer does not put offspring at additional risk for adverse perinatal or health outcomes

Immunotherapeutic targeting of membrane Hsp70-expressing tumors using recombinant human granzyme B

Background: We have previously reported that human recombinant granzyme B (grB) mediates apoptosis in membrane heat shock protein 70 (Hsp70)-positive tumor cells in a perforin-independent manner

Fertility education for adolescent cancer patients: Gaps in current clinical practice in Europe

Objective: As adolescent cancer patients may suffer from infertility following treatment, fertility counselling is essential. Our aim was to explore the current situation in four European countries in terms of (I) education about the risk for infertility, (II) counselling on fertility preservation, (III) patients' knowledge on fertility, (IV) sufficiency of information and (V) uptake of cryopreservation. Methods: In total, 113 patients (13–20 years) at 11 study centres completed a self-report questionnaire three and six months after cancer diagnosis. Multivariate logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI). Results: As many as 80.2% of participants reported having received education about the risk for infertility prior to treatment, 73.2% recalled counselling on fertility preservation. Only 52.3% stated they felt sufficiently informed to make a decision. Inability to recall counselling on fertility preservation (OR = 0.03, CI: 0.00–0.47) and female gender (OR = 0.11, CI: 0.03–0.48) was associated with lower use of cryopreservation, whereas older age was associated with higher use. Conclusion: Fertility counselling was available to a relatively high proportion of patients, and it did influence the utilisation of cryopreservation. However, many patients did not feel sufficiently informed. Further improvement is needed to enable adolescent cancer patients to make an informed decision on fertility preservation

Epigenome-wide association study in peripheral tissues highlights DNA methylation profiles associated with episodic memory performance in humans

The decline in episodic memory (EM) performance is a hallmark of cognitive aging and an early clinical sign in Alzheimer&rsquo;s disease (AD). In this study, we conducted an epigenome-wide association study (EWAS) using DNA methylation (DNAm) profiles from buccal and blood samples for cross-sectional (n = 1019) and longitudinal changes in EM performance (n = 626; average follow-up time 5.4 years) collected under the auspices of the Lifebrain consortium project. The mean age of participants with cross-sectional data was 69 &plusmn; 11 years (30&ndash;90 years), with 50% being females. We identified 21 loci showing suggestive evidence of association (p &lt; 1 &times; 10&minus;5) with either or both EM phenotypes. Among these were SNCA, SEPW1 (both cross-sectional EM), ITPK1 (longitudinal EM), and APBA2 (both EM traits), which have been linked to AD or Parkinson&rsquo;s disease (PD) in previous work. While the EM phenotypes were nominally significantly (p &lt; 0.05) associated with poly-epigenetic scores (PESs) using EWASs on general cognitive function, none remained significant after correction for multiple testing. Likewise, estimating the degree of &ldquo;epigenetic age acceleration&rdquo; did not reveal significant associations with either of the two tested EM phenotypes. In summary, our study highlights several interesting candidate loci in which differential DNAm patterns in peripheral tissue are associated with EM performance in humans

SUCLA2 mutations cause global protein succinylation contributing to the pathomechanism of a hereditary mitochondrial disease

Mitochondrial acyl-coenzyme A species are emerging as important sources of protein modification and damage. Succinyl-CoA ligase (SCL) deficiency causes a mitochondrial encephalomyopathy of unknown pathomechanism. Here, we show that succinyl-CoA accumulates in cells derived from patients with recessive mutations in the tricarboxylic acid cycle (TCA) gene succinyl-CoA ligase subunit-beta (SUCLA2), causing global protein hyper-succinylation. Using mass spectrometry, we quantify nearly 1,000 protein succinylation sites on 366 proteins from patient-derived fibroblasts and myotubes. Interestingly, hyper-succinylated proteins are distributed across cellular compartments, and many are known targets of the (NAD(+))-dependent desuccinylase SIRT5. To test the contribution of hyper-succinylation to disease progression, we develop a zebrafish model of the SCL deficiency and find that SIRT5 gain-of-function reduces global protein succinylation and improves survival. Thus, increased succinyl-CoA levels contribute to the pathology of SCL deficiency through post-translational modifications. The pathomechanism of succinyl-CoA ligase (SCL) deficiency, a hereditary mitochondrial disease, is not fully understood. Here, the authors show that increased succinyl-CoA levels contribute to SCL pathology by causing global protein hyper-succinylation.Peer reviewe