HIV-1 Epidemic in the Caribbean Is Dominated by Subtype B

The molecular epidemiology of HIV-1 in the Caribbean has been described using partial genome sequencing; subtype B is the most common subtype in multiple countries. To expand our knowledge of this, nearly full genome amplification, sequencing and analysis was conducted.Virion RNA from sera collected in Haiti, Dominican Republic, Jamaica and Trinidad and Tobago were reverse transcribed, PCR amplified, sequenced and phylogenetically analyzed. Nearly full genomes were completed for 15 strains; partial pol was done for 67 strains. All but one of the 67 strains analyzed in pol were subtype B; the exception was a unique recombinant of subtypes B and C collected in the Dominican Republic. Of the nearly full genomes of 14 strains that were subtype B in pol, all were subtype B from one end of the genome to the other and not inter-subtype recombinants. Surprisingly, the Caribbean subtype B strains clustered significantly with each other and separate from subtype B from other parts of the pandemic.The more complete analysis of HIV-1 from 4 Caribbean countries confirms previous research using partial genome analysis that the predominant subtype in circulation was subtype B. The Caribbean strains are phylogenetically distinct from other subtype B strains although the biological meaning of this finding is unclear

Authoritarian Regime Learning: Comparative Insights from the Arab Uprisings

This paper examines the learning of authoritarian regimes in the early phase of the Arab uprisings. Differentiating conceptually between learning and policy change, we analyze and compare the authoritarian regimes of Algeria, Bahrain, Jordan, and Syria and their reactions to the challenge of "late riser" oppositional protests. We first show that the four regimes initiated very diverse measures in the domains of repression, material co-optation, and legal reforms. With regard to the sources of learning, we find that proximity is a determining factor, in terms of both geography and political similarity. Using the case of Bahrain, we then demonstrate that structural factors such as internal power structures, regional and international pressures, or state capacity can decisively constrain the implementation of learning-induced policy change. Overall, the paper aims to contribute to the emerging research on the international dimension of authoritarian regimes in the Middle East and beyond

Truck drivers' perceptions on wearable devices and health promotion:A qualitative study

Professional truck drivers, as other shift workers, have been identified as a high-risk group for various health conditions including cardiovascular disease, obesity, diabetes, sleep apnoea and stress. Mobile health technologies can potentially improve the health and wellbeing of people with a sedentary lifestyle such as truck drivers. Yet, only a few studies on health promotion interventions related to mobile health technologies for truck drivers have been conducted. We aimed to explore professional truck drivers views on health promotion delivered via mobile health technologies such as wearable devices.We conducted a phenomenological qualitative study, consisting of four semi-structured focus groups with 34 full-time professional truck drivers in the UK. The focus groups were audio-taped, transcribed verbatim and analysed using thematic content analysis. We discussed drivers perceptions of their health, lifestyle and work environment, and their past experience and expectations from mobile health technologies.The participants viewed their lifestyle as unhealthy and were aware of possible consequences. They expressed the need and wish to change their lifestyle, yet perceived it as an inherent, unavoidable outcome of their occupation. Current health improvement initiatives were not always aligned with their working conditions. The participants were generally willing to use mobile health technologies such as wearable devices, as a preventive measure to avoid prospect morbidity, particularly cardiovascular diseases. They were ambivalent about privacy and the risk of their employers monitoring their clinical data.Wearable devices may offer new possibilities for improving the health and wellbeing of truck drivers. Drivers were aware of their unhealthy lifestyle. They were interested in changing their lifestyle and health. Drivers raised concerns regarding being continuously monitored by their employer. Health improvement initiatives should be aligned with the unique working conditions of truck drivers. Future research is needed to examine the impact of wearable devices on improving the health and wellbeing of professional drivers

Alternative HER/PTEN/Akt Pathway Activation in HPV Positive and Negative Penile Carcinomas

Copyright: 2011 Stankiewicz et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: The pathogenesis of penile squamous cell carcinoma (PSCC) is not well understood, though risk factors include human papillomavirus (HPV). Disruption of HER/PTEN/Akt pathway is present in many cancers; however there is little information on its function in PSCC. We investigated HER family receptors and phosphatase and tension homolog (PTEN) in HPV-positive and negative PSCC and its impact on Akt activation using immunohistochemistry and fluorescent in situ hybridisation (FISH). Methodology/Principal Findings: 148 PSCCs were microarrayed and immunostained for phosphorylated EGFR (pEGFR), HER2, HER3, HER4, phosphorylated Akt (pAkt), Akt1 and PTEN proteins. EGFR and PTEN gene status were also evaluated using FISH. HPV presence was assessed by PCR. pEGFR expression was detected significantly less frequently in HPV-positive than HPV-negative tumours (p = 0.0143). Conversely, HER3 expression was significantly more common in HPV-positive cases (p = 0.0128). HER4, pAkt, Akt and PTEN protein expression were not related to HPV. HER3 (p = 0.0054) and HER4 (p = 0.0002) receptors significantly correlated with cytoplasmic Akt1 immunostaining. All three proteins positively correlated with tumour grade (HER3, p = 0.0029; HER4, p = 0.0118; Akt1, p = 0.0001). pEGFR expression correlated with pAkt but not with tumour grade or stage. There was no EGFR gene amplification. HER2 was not detected. PTEN protein expression was reduced or absent in 62% of tumours but PTEN gene copy loss was present only in 4% of PSCCs. Conclusions/Significance: EGFR, HER3 and HER4 but not HER2 are associated with penile carcinogenesis. HPV-negative tumours tend to express significantly more pEGFR than HPV-positive cancers and this expression correlates with pAkt protein, indicating EGFR as an upstream regulator of Akt signalling in PSCC. Conversely, HER3 expression is significantly more common in HPV-positive cases and positively correlates with cytoplasmic Akt1 expression. HER4 and PTEN protein expression are not related to HPV infection. Our results suggest that PSCC patients could benefit from therapies developed to target HER receptors.Peer reviewedFinal Published versio

Aberrant Expression of Proteins Involved in Signal Transduction and DNA Repair Pathways in Lung Cancer and Their Association with Clinical Parameters

Because cell signaling and cell metabolic pathways are executed through proteins, protein signatures in primary tumors are useful for identifying key nodes in signaling networks whose alteration is associated with malignancy and/or clinical outcomes. This study aimed to determine protein signatures in primary lung cancer tissues.We analyzed 126 proteins and/or protein phosphorylation sites in case-matched normal and tumor samples from 101 lung cancer patients with reverse-phase protein array (RPPA) assay. The results showed that 18 molecules were significantly different (p<0.05) by at least 30% between normal and tumor tissues. Most of those molecules play roles in cell proliferation, DNA repair, signal transduction and lipid metabolism, or function as cell surface/matrix proteins. We also validated RPPA results by Western blot and/or immunohistochemical analyses for some of those molecules. Statistical analyses showed that Ku80 levels were significantly higher in tumors of nonsmokers than in those of smokers. Cyclin B1 levels were significantly overexpressed in poorly differentiated tumors while Cox2 levels were significantly overexpressed in neuroendocrinal tumors. A high level of Stat5 is associated with favorable survival outcome for patients treated with surgery.Our results revealed that some molecules involved in DNA damage/repair, signal transductions, lipid metabolism, and cell proliferation were drastically aberrant in lung cancer tissues, and Stat5 may serve a molecular marker for prognosis of lung cancers

The Glycosylphosphatidylinositol-PLC in Trypanosoma brucei Forms a Linear Array on the Exterior of the Flagellar Membrane Before and After Activation

Bloodstream forms of Trypanosoma brucei contain a glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) that cleaves the GPI-anchor of the variable surface glycoprotein (VSG). Its location in trypanosomes has been controversial. Here, using confocal microscopy and surface labelling techniques, we show that the GPI-PLC is located exclusively in a linear array on the outside of the flagellar membrane, close to the flagellar attachment zone, but does not co-localize with the flagellar attachment zone protein, FAZ1. Consequently, the GPI-PLC and the VSG occupy the same plasma membrane leaflet, which resolves the topological problem associated with the cleavage reaction if the VSG and the GPI-PLC were on opposite sides of the membrane. The exterior location requires the enzyme to be tightly regulated to prevent VSG release under basal conditions. During stimulated VSG release in intact cells, the GPI-PLC did not change location, suggesting that the release mechanism involves lateral diffusion of the VSG in the plane of the membrane to the fixed position of the GPI-PLC

Peroxiredoxin 3 Is a Redox-Dependent Target of Thiostrepton in Malignant Mesothelioma Cells

Thiostrepton (TS) is a thiazole antibiotic that inhibits expression of FOXM1, an oncogenic transcription factor required for cell cycle progression and resistance to oncogene-induced oxidative stress. The mechanism of action of TS is unclear and strategies that enhance TS activity will improve its therapeutic potential. Analysis of human tumor specimens showed FOXM1 is broadly expressed in malignant mesothelioma (MM), an intractable tumor associated with asbestos exposure. The mechanism of action of TS was investigated in a cell culture model of human MM. As for other tumor cell types, TS inhibited expression of FOXM1 in MM cells in a dose-dependent manner. Suppression of FOXM1 expression and coincidental activation of ERK1/2 by TS were abrogated by pre-incubation of cells with the antioxidant N-acetyl-L-cysteine (NAC), indicating its mechanism of action in MM cells is redox-dependent. Examination of the mitochondrial thioredoxin reductase 2 (TR2)-thioredoxin 2 (TRX2)-peroxiredoxin 3 (PRX3) antioxidant network revealed that TS modifies the electrophoretic mobility of PRX3. Incubation of recombinant human PRX3 with TS in vitro also resulted in PRX3 with altered electrophoretic mobility. The cellular and recombinant species of modified PRX3 were resistant to dithiothreitol and SDS and suppressed by NAC, indicating that TS covalently adducts cysteine residues in PRX3. Reduction of endogenous mitochondrial TRX2 levels by the cationic triphenylmethane gentian violet (GV) promoted modification of PRX3 by TS and significantly enhanced its cytotoxic activity. Our results indicate TS covalently adducts PRX3, thereby disabling a major mitochondrial antioxidant network that counters chronic mitochondrial oxidative stress. Redox-active compounds like GV that modify the TR2/TRX2 network may significantly enhance the efficacy of TS, thereby providing a combinatorial approach for exploiting redox-dependent perturbations in mitochondrial function as a therapeutic approach in mesothelioma

Thermodynamic Additivity of Sequence Variations: An Algorithm for Creating High Affinity Peptides Without Large Libraries or Structural Information

BACKGROUND: There is a significant need for affinity reagents with high target affinity/specificity that can be developed rapidly and inexpensively. Existing affinity reagent development approaches, including protein mutagenesis, directed evolution, and fragment-based design utilize large libraries and/or require structural information thereby adding time and expense. Until now, no systematic approach to affinity reagent development existed that could produce nanomolar affinity from small chemically synthesized peptide libraries without the aid of structural information. METHODOLOGY/PRINCIPAL FINDINGS: Based on the principle of additivity, we have developed an algorithm for generating high affinity peptide ligands. In this algorithm, point-variations in a lead sequence are screened and combined in a systematic manner to achieve additive binding energies. To demonstrate this approach, low-affinity lead peptides for multiple protein targets were identified from sparse random sequence space and optimized to high affinity in just two chemical steps. In one example, a TNF-α binding peptide with K(d) = 90 nM and high target specificity was generated. The changes in binding energy associated with each variation were generally additive upon combining variations, validating the basis of the algorithm. Interestingly, cooperativity between point-variations was not observed, and in a few specific cases, combinations were less than energetically additive. CONCLUSIONS/SIGNIFICANCE: By using this additivity algorithm, peptide ligands with high affinity for protein targets were generated. With this algorithm, one of the highest affinity TNF-α binding peptides reported to date was produced. Most importantly, high affinity was achieved from small, chemically-synthesized libraries without the need for structural information at any time during the process. This is significantly different than protein mutagenesis, directed evolution, or fragment-based design approaches, which rely on large libraries and/or structural guidance. With this algorithm, high affinity/specificity peptide ligands can be developed rapidly, inexpensively, and in an entirely chemical manner

The SNX-PX-BAR Family in Macropinocytosis: The Regulation of Macropinosome Formation by SNX-PX-BAR Proteins

Background: Macropinocytosis is an actin-driven endocytic process, whereby membrane ruffles fold back onto the plasma membrane to form large (> 0.2 mu m in diameter) endocytic organelles called macropinosomes. Relative to other endocytic pathways, little is known about the molecular mechanisms involved in macropinocytosis. Recently, members of the Sorting Nexin (SNX) family have been localized to the cell surface and early macropinosomes, and implicated in macropinosome formation. SNX-PX-BAR proteins form a subset of the SNX family and their lipid-binding (PX) and membrane-curvature sensing (BAR) domain architecture further implicates their functional involvement in macropinosome formation

Structural Elements Regulating Amyloidogenesis: A Cholinesterase Model System

Polymerization into amyloid fibrils is a crucial step in the pathogenesis of neurodegenerative syndromes. Amyloid assembly is governed by properties of the sequence backbone and specific side-chain interactions, since fibrils from unrelated sequences possess similar structures and morphologies. Therefore, characterization of the structural determinants driving amyloid aggregation is of fundamental importance. We investigated the forces involved in the amyloid assembly of a model peptide derived from the oligomerization domain of acetylcholinesterase (AChE), AChE586-599, through the effect of single point mutations on β-sheet propensity, conformation, fibrilization, surfactant activity, oligomerization and fibril morphology. AChE586-599 was chosen due to its fibrilization tractability and AChE involvement in Alzheimer's disease. The results revealed how specific regions and residues can control AChE586-599 assembly. Hydrophobic and/or aromatic residues were crucial for maintaining a high β-strand propensity, for the conformational transition to β-sheet, and for the first stage of aggregation. We also demonstrated that positively charged side-chains might be involved in electrostatic interactions, which could control the transition to β-sheet, the oligomerization and assembly stability. Further interactions were also found to participate in the assembly. We showed that some residues were important for AChE586-599 surfactant activity and that amyloid assembly might preferentially occur at an air-water interface. Consistently with the experimental observations and assembly models for other amyloid systems, we propose a model for AChE586-599 assembly in which a steric-zipper formed through specific interactions (hydrophobic, electrostatic, cation-π, SH-aromatic, metal chelation and polar-polar) would maintain the β-sheets together. We also propose that the stacking between the strands in the β-sheets along the fiber axis could be stabilized through π-π interactions and metal chelation. The dissection of the specific molecular recognition driving AChE586-599 amyloid assembly has provided further knowledge on such poorly understood and complicated process, which could be applied to protein folding and the targeting of amyloid diseases