Month: November 2020

Intracellular copper deposits impede inhibitor of apoptosis proteins, which eventually causes apoptotic cell death. The clinical presentation varies from predominantly hepatic to predominantly neurologic and shows great heterogeneity regarding severity, age of onset and initial symptoms. Wilson’s GSI-IX disease results in severe disability and death if untreated. The key neurological features comprise extrapyramidal symptoms, ataxia, dystonia, seizures and psychiatric symptoms, such as personality changes, depression and psychosis. Structural changes in the brain of Wilson’s disease patients have been well documented by magnetic resonance imaging, which has revealed lesions of the basal ganglia, midbrain, pons and cerebellum and widespread cortical atrophy and white matter changes. Histological studies have reported necrosis, gliosis and cystic changes in the brainstem, thalamus, cerebellum and cerebral cortex of Wilson’s disease patients. The functional consequences of these structural changes have been demonstrated in the acoustic, sensory, motor and visual systems and are reflected by disordered multimodality evoked potentials. Visual evoked potentials have been reported to be abnormal in approximately 50% of symptomatic Wilson’s disease patients. Common ocular findings of Wilson’s disease include the Kayser–Fleischer ring and sunflower cataracts. Both are due to copper deposition and do not cause visual impairment, suggesting that the observed pathologies in VEPs may be explained by retroocular changes. However, altered flash electroretinograms in Wilson’s disease are indicative of a retinal pathology. Optical coherence tomography is a fast and non-invasive technique and the latest generation of OCT devices is capable of depicting retinal changes at nearly the cellular level. In this study, we used up-to-date OCT technology to analyze the retinal changes in Wilson’s disease patients. We compared the morphological changes measured by a state-of-theart spectral domain OCT device with VEPs as functional parameters and correlated these findings with laboratory parameters and a clinical Wilson’s disease score. We were able to reproduce previously reported findings that indicate that in Wilson’s disease, VEP latencies are delayed. We believe that the prolonged P100 latencies are likely to reflect a slowed conduction velocity of the visual tract caused by copper deposits. A structural analysis of the retina by OCT revealed reduced thickness of the RNFL, total macula and GCIP, clearly indicating pathological changes to the retinal ganglion cells and their axons in the retina. In line with previous publications, the VEP amplitudes of Wilson’s disease patients were unchanged compared with controls. However, in Wilson’s disease patients, low VEP amplitudes tended to be associated with thinner RNFL, GCIP and total macular thickness, although these correlations failed to reach significance. In other diseases such as multiple sclerosis, the VEP amplitude is reported to correlate with the RNFL thickness. It is possible that the extent of axonal loss in Wilson’s disease patients was not sufficient to significantly reduce the VEP amplitude. However, these findings indicate that OCT may be a more sensitive parameter of axonal loss in Wilson’s disease than VEP amplitudes. To our knowledge, no histopathological studies analyzing the retinae of patients with Wilson’s disease have been reported, so the exact mechanisms of retinal degeneration in these patients remain unclear. However, the reduction of RNFL thickness in Wilson’s disease reflects degeneration of the retinal ganglion cell axons and degeneration of the retinal ganglion cells themselves and is likely to account for the observed reduced thickness of the GCIP complex.

In conclusion, we identified brain mitochondrial proteins in p53 null mice that display crucial p53-dependent cellular functions in the central nervous system. Therefore, our results reinforce the concept that the lack of p53 could disturb cell homeostasis causing cells to stimulate defensive pathways. We also elaborated on the link between p53 and mitochondria as we used for the study mitochondria from p53 knock out mice. Since mitochondrial dysfunction is a key feature of neurodegenerative diseases such as AD, p53 conceivably could be a novel therapeutic target for the treatment of these disorders. Molecular features of solid tumours become central in tailoring targeted therapies, but the accessibility to tumour tissue may be sometimes limited due to the size of bioptic samples or the unavailability of biological material, particularly during patients’ follow up. In this context cancer-derived cell-free DNA in blood represents a promising biomarker for cancer diagnosis and an useful surrogate material for molecular characterization. The two classes of alterations detectable in cfDNA from cancer patients include quantitative and qualitative abnormalities. Concerning the former aspect, it is now evident that cancer patients have a higher concentration of cfDNA than healthy individuals. The concentration of cfDNA is influenced by tumor stage, size, location, and other factors. On the other hand, increased plasma DNA level is not a specific cancer marker, as it is observed also in patients with premalignant states, inflammation or trauma. Total cfDNA concentration has been proposed as a marker for early cancer detection, but the studies conducted so far showed a ICI 182780 scarce discriminatory power between patients and controls as well as limited sensitivity and specificity, not allowing one to reach any final conclusion on the diagnostic impact of this parameter. Several studies report a prognostic value of total cfDNA, while conflicting results have been obtained in testing this marker for therapy monitoring. The reduced specificity of this quantitative test leads us to evaluate additional biomarkers reflecting qualitative alterations in cfDNA. A higher specificity in cancer diagnosis can be achieved by detecting tumor specific alterations in cfDNA, such as DNA integrity, genetic and epigenetic modifications. Blood cfDNA in cancer patients originates from apoptotic or necrotic cells. In solid cancers, necrosis generates a spectrum of DNA fragments with variable size, due to random digestion by DNases. In contrast, cell death in normal blood nucleated cells occurs mostly via apoptosis that generates small and uniform DNA fragments. It has generally been observed that in patients affected by several neoplastic diseases plasma DNA contains longer fragments than in healthy subjects reflected by the increase of DNA integrity index. The above mentioned parameters can obviously be considered as non-specific biomarkers, since the increase of cfDNA concentration and integrity is common to the large majority of human solid cancers. When cfDNA is used to detect genetic and epigenetic modifications in a specific tumor, it is necessary to select definite molecular targets that are expected to be altered in affected patients. In cutaneous melanoma, the oncogene BRAF is frequently mutated. BRAF is a serine–threonine protein kinase involved in the RAS–RAF–MEK–ERK pathway which regulates cell growth, survival, differentiation and senescence. The oncogene BRAF is frequently mutated in other human cancers constitutively activating the MAPK pathway. The most common BRAF mutation, which accounts for more than 90% of cases of cancer involving this gene, is the T1799A transversion, converting valine to glutamic acid at position 600.

The conformational flexibility of GPCRs, but also to the sensitivity of docking to small changes in the protein structure. In combination, it can be exploited to identify larger numbers of ligands by docking to more than one protein conformation. Any model of a protein structure represents only one possibility from the continuum of conformations. Thus, using differently optimized models, the set of identified ligands would have changed. Yet, the overall performance, with some models being able to recognize ligands and some not, would be similar. This fact might also be considered disheartening for approaches that aim to include receptor flexibility via docking to multiple conformations of a receptor and calculating the average rank of a molecule across all structures. Eukaryotic transcription factors are AbMole BioScience Life Science Reagents grouped into families based on their common DNA binding domains. Due to their similarity of their DNA binding domains, proteins within families have the potential to bind to similar DNA motifs and this has been shown to be the case for the ETS transcription factors where only subtle differences in binding specificity can be observed in vitro. Given that there are 28 ETS family members in mammals and that they possess a similar binding potential it is unclear how biological specificity is achieved. However, insights into this have been provided by several genome-wide ChIP-seq/ChIP-chip studies, where it is clear that although there is substantial overlap in DNA binding in vivo, individual family members preferentially bind to subsets of sites. It seems likely that binding to these ‘exclusive’ sites accounts for the specificity of action of particular ETS factors. Indeed, we recently showed that in breast epithelial MCF10A cells, ELK1 binds to DNA in vivo in two distinct manners, either overlapping with binding of another ETS protein GABPA or binding to a different set of sites to GABPA. Importantly, ELK1 was shown to control cell migration and it does so through regulating the expression of genes associated with ‘unique’ ELK1 binding sites. This study therefore confirmed the hypothesis that a specific biological effect can be elicited by the binding of a single family member, in this case ELK1, to a series of target genes that are not targeted by other family members. In addition to the specific role for ELK1 in controlling MCF10A cell migration, a large number of genes targeted by ELK1 overlap with the binding of GABPA. Similarly, in human T cell lines, GABPA binding substantially overlaps that of the other ETS proteins ETS1 and ELF1. In this overlapping binding mode, GABPA is thought to control the activities of housekeeping genes such as those encoding ribosomal proteins. However, it is not clear whether GABPA functions to control specific sets of genes in an independent manner from other ETS proteins and hence drive distinct biological processes. Such a specific function appears likely, as GABPA has previously been associated with controlling many different processes. For example, it was recently demonstrated to play an important role in haematopoietic stem cell maintenance and differentiation. It also has a role as a controller of cell cycle progression and is important for the formation of a functional postsynaptic apparatus in neurons. These studies suggest that GABPA likely binds in a ‘unique’ manner to sets of genes controlling these processes. In this study we investigated the functional role of GABPA in MCF10A cells. As our previous results showed that ELK1 controls breast epithelial cell migration and this happens through regulating a set of target genes that are apparently ‘unique’ to ELK1 and not also bound by GABPA, we therefore assumed that GABPA would not affect cell migration and instead would control different biological processes.

Each ring type may be particularly suited for different purposes where flexibility or rigidity is advantageous. In terms of a static view of the stability of ring proteins, symmetry itself may not be a determinant of the stability. The smaller population of the 12-mer TRAP compared with the 11- mer is primarily attributed to subtle differences in the inter-subunit interactions. Antson et al. recently found that B. halodurans TRAP exclusively forms a 12-mer ring. The crystal structure of the 12-mer B. halodurans TRAP showed the C-terminal residues with a conformation different from those of the 11-mer TRAP of B. subtilis or B. stearothermophilus, which forms different interactions with the adjacent subunit allowing an increase in the diameter of the ring. However, the present study shows that symmetry significantly influences dynamics, and should be another important factor for not only stability but also biological function of ring proteins, especially for large ring structures like the present case of C11 and C12. The emergence of rapid resistance to antibiotics among major pathogens remains a serious threat to public health. To overcome this challenge, many laboratories pursue drug discovery efforts to identify novel structural classes of antibiotics. However, a limited understanding of the molecular mechanism of action is a critical bottleneck in the development of novel classes of antibacterial agents. Therefore, more detailed studies into the mechanism of microbial death resulting from Ibrutinib antibiotic use and the reason for the drug resistance of pathogens is required. Antibacterial peptides, a cluster of small peptides secreted by most organisms, represent a promising new class of antibiotic drugs. They are known to be active against a wide range of microorganisms including bacteria, protozoa, yeast fungi, viruses, and even tumor cells. These active polypeptides have characteristics of small molecular mass, high efficacy, stability, particular antibacterial mechanism, and little drug resistance. Fusaricidin A was elucidated to be a cyclic depsipeptide containing a unique fatty acid, 15-guanidino-3-hydroxypentadecanoic acid. Fusaricidins B, C, and D are minor components from the culture broth of a bacterial strain Bacillus polymyxa KT-8. Their structures have been elucidated to be cyclic hexadepsipeptide, very similar to that of fusaricidin A. Fusaricidins C and D displayed strong activity against gram-positive bacteria, especially Staphylococcus aureus FDA 209P, S. aureus, and Micrococcus luteus IFO 3333 as did fusaricidin A, whereas fusaricidin B showed weaker activity against those microbes than the fusaricidin C and D mixture. However, fusaricidin, even at 100 mg/mL, showed no activity against all the gram-negative bacteria tested. Despite their promising antimicrobial profile, much remains to be determined regarding the MoA of fusaricidins and the development of microbial resistance to the compounds. In this report, we used genome-wide expression technologies to elucidate bacterial defense mechanisms responsible for fusaricidin resistance; this strategy is increasingly used in the antibiotic research field. As a model organism, we chose B. subtilis 168, a grampositive, spore-forming bacterium that is ubiquitously distributed in soil. The complete genome of B. subtilis 168 was sequenced in 1997 and is reported to encode 4,106 proteins. The availability of this genomic sequence provides a cost-effective opportunity to explore genomic variation between strains. Trancriptomic analysis is a powerful approach to elucidate the inhibitory mechanisms of novel antimicrobial compounds and has been successfully applied to characterize and differentiate antimicrobial actions, often using B. subtilis as a model organism.

In this study, we found a positive correlation between IL-1b production and cytotoxicity induced by EHEC-Ehx. Even the cytotoxicity of Ehx has been found to contribute to the release of IL-1b through cell lysis, which cannot be the main source of extracellular IL-1b because most of the IL-1b in the supernatant was biologically active mature IL-1b, as shown by immunoblot analysis. Further experiments are needed to determine the mechanism by which cytotoxicity of Ehx affects the secretion of mature IL-1b into the extracellular space and how cytotoxic Ehx affects the pathogenesis of EHEC infection. In this study, we found EHEC O157:H7-Ehx to contribute to cytotoxicity in THP-1 cells. It was also found responsible for higher levels of mature IL-1b. The NLRP3 inflammasome was found to mediate EHEC O157:H7-activated IL-1b production. Ehx may activate pro-caspase-1 through activation of NLRP3, like other pore-form bacteria toxins. However, the possibility that other types of inflammasome signaling may be activated by Ehx cannot yet be ruled out. This may also have stimulated the release of IL-1b. Cytotoxicity to THP-1 cells may also contribute to the release of IL-1b using some as yet unknown mechanism. Further study is needed to determine the possible roles of IL-1b in the pathogenesis of this potentially fatal foodborne infection. Genomic imprinting is an epigenetic phenomenon observed in eutherian mammals. For the large majority of autosomal genes, the two parental copies are both either transcribed or silent. However, in a small group of genes one copy is turned off in a parent-of-origin specific manner thereby resulting in monoallelic expression. These genes are called ‘imprinted’ because the silenced copy of the gene is epigenetically marked or imprinted in either the egg or the sperm. Imprinted genes play important roles in development and growth both pre- and Staurosporine postnatally by acting in fetal and placental tissues. Interestingly, there appears to exist a general pattern whereby maternally expressed genes tend to limit embryonic growth and paternally expressed genes tend to promote growth. A model case for this striking scenario is the antagonistic action of Igf2 and Igf2r in mouse. Deletion of the paternally expressed Igf2 gene results in intrauterine growth restriction. On the other hand, deletion of the maternally expressed gene Igf2r, results in overgrowth. The observation that maternally and paternally expressed genes apparently act as antagonists has inspired several evolutionary theories that aim to explain the origin of genetic imprinting under the process of ‘natural selection’. The most scientifically accepted theory is currently the kinship theory and. Briefly, this theory suggests that in polygamous mammalian species, silencing of maternally derived growth inhibiting genes results in increased growth of the embryo. This is associated with an increased nutritional demand and thereby with an exploitation of maternal resources at the cost of future off-spring that might be fathered by a different male. The evolution of a gene regulatory mechanism that silences preferentially one parental allele of a gene implies that paternally and maternally expressed genes experience different selective pressures during evolution. This assumption is supported by the finding that the two groups reveal different patterns of sequence conservation. Whereas the protein-encoding DNA sequences of paternally expressed genes are well conserved among different mammalian species, maternally expressed genes are much more divergent. Whether paternally and maternally expressed genes differ also in molecular functions and gene regulation is a question that has not yet been investigated in detail.