Inhibition of cellular protein secretion by norwalk virus nonstructural protein p22 requires a mimic of an endoplasmic reticulum export signal.

Protein trafficking between the endoplasmic reticulum (ER) and Golgi apparatus is central to cellular homeostasis. ER export signals are utilized by a subset of proteins to rapidly exit the ER by direct uptake into COPII vesicles for transport to the Golgi. Norwalk virus nonstructural protein p22 contains a YXΦESDG motif that mimics a di-acidic ER export signal in both sequence and function. However, unlike normal ER export signals, the ER export signal mimic of p22 is necessary for apparent inhibition of normal COPII vesicle trafficking, which leads to Golgi disassembly and antagonism of Golgi-dependent cellular protein secretion. This is the first reported function for p22. Disassembly of the Golgi apparatus was also observed in cells replicating Norwalk virus, which may contribute to pathogenesis by interfering with cellular processes that are dependent on an intact secretory pathway. These results indicate that the ER export signal mimic is critical to the antagonistic function of p22, shown herein to be a novel antagonist of ER/Golgi trafficking. This unique and well-conserved human norovirus motif is therefore an appealing target for antiviral drug development

Tetraspanin 6: a pivotal protein of the multiple vesicular body determining exosome release and lysosomal degradation of amyloid precursor protein fragments

BACKGROUND: The mechanisms behind Aβ-peptide accumulation in non-familial Alzheimer’s disease (AD) remain elusive. Proteins of the tetraspanin family modulate Aβ production by interacting to γ-secretase. METHODS: We searched for tetraspanins with altered expression in AD brains. The function of the selected tetraspanin was studied in vitro and the physiological relevance of our findings was confirmed in vivo. RESULTS: Tetraspanin-6 (TSPAN6) is increased in AD brains and overexpression in cells exerts paradoxical effects on Amyloid Precursor Protein (APP) metabolism, increasing APP-C-terminal fragments (APP-CTF) and Aβ levels at the same time. TSPAN6 affects autophagosome-lysosomal fusion slowing down the degradation of APP-CTF. TSPAN6 recruits also the cytosolic, exosome-forming adaptor syntenin which increases secretion of exosomes that contain APP-CTF. CONCLUSIONS: TSPAN6 is a key player in the bifurcation between lysosomal-dependent degradation and exosome mediated secretion of APP-CTF. This corroborates the central role of the autophagosomal/lysosomal pathway in APP metabolism and shows that TSPAN6 is a crucial player in APP-CTF turnover

Methylglyoxal Produced by Amyloid- Peptide-Induced Nitrotyrosination of Triosephosphate Isomerase Triggers Neuronal Death in Alzheimer’s Disease

Amyloid-β peptide (Aβ) aggregates induce nitro-oxidative stress, contributing to the characteristic neurodegeneration found in Alzheimer's disease (AD). One of the most strongly nitrotyrosinated proteins in AD is the triosephosphate isomerase (TPI) enzyme which regulates glycolytic flow, and its efficiency decreased when it is nitrotyrosinated. The main aims of this study were to analyze the impact of TPI nitrotyrosination on cell viability and to identify the mechanism behind this effect. In human neuroblastoma cells (SH-SY5Y), we evaluated the effects of Aβ42 oligomers on TPI nitrotyrosination. We found an increased production of methylglyoxal (MG), a toxic byproduct of the inefficient nitro-TPI function. The proapoptotic effects of Aβ42 oligomers, such as decreasing the protective Bcl2 and increasing the proapoptotic caspase-3 and Bax, were prevented with a MG chelator. Moreover, we used a double mutant TPI (Y165F and Y209F) to mimic nitrosative modifications due to Aβ action. Neuroblastoma cells transfected with the double mutant TPI consistently triggered MG production and a decrease in cell viability due to apoptotic mechanisms. Our data show for the first time that MG is playing a key role in the neuronal death induced by Aβ oligomers. This occurs because of TPI nitrotyrosination, which affects both tyrosines associated with the catalytic center

High variety of known and new RNA and DNA viruses of diverse origins in untreated sewage

Deep sequencing of untreated sewage provides an opportunity to monitor enteric infections in large populations and for high-throughput viral discovery. A metagenomics analysis of purified viral particles in untreated sewage from the United States (San Francisco, CA), Nigeria (Maiduguri), Thailand (Bangkok), and Nepal (Kathmandu) revealed sequences related to 29 eukaryotic viral families infecting vertebrates, invertebrates, and plants (BLASTx E score, <10(−4)), including known pathogens (>90% protein identities) in numerous viral families infecting humans (Adenoviridae, Astroviridae, Caliciviridae, Hepeviridae, Parvoviridae, Picornaviridae, Picobirnaviridae, and Reoviridae), plants (Alphaflexiviridae, Betaflexiviridae, Partitiviridae, Sobemovirus, Secoviridae, Tombusviridae, Tymoviridae, Virgaviridae), and insects (Dicistroviridae, Nodaviridae, and Parvoviridae). The full and partial genomes of a novel kobuvirus, salivirus, and sapovirus are described. A novel astrovirus (casa astrovirus) basal to those infecting mammals and birds, potentially representing a third astrovirus genus, was partially characterized. Potential new genera and families of viruses distantly related to members of the single-stranded RNA picorna-like virus superfamily were genetically characterized and named Picalivirus, Secalivirus, Hepelivirus, Nedicistrovirus, Cadicistrovirus, and Niflavirus. Phylogenetic analysis placed these highly divergent genomes near the root of the picorna-like virus superfamily, with possible vertebrate, plant, or arthropod hosts inferred from nucleotide composition analysis. Circular DNA genomes distantly related to the plant-infecting Geminiviridae family were named Baminivirus, Nimivirus, and Niminivirus. These results highlight the utility of analyzing sewage to monitor shedding of viral pathogens and the high viral diversity found in this common pollutant and provide genetic information to facilitate future studies of these newly characterized viruses

Structural analysis on mutation residues and interfacial water molecules for human TIM disease understanding

10.1186/1471-2105-14-S16-S11BMC Bioinformatics14SUPPL16-BBMI

Early and reversible changes to the hippocampal proteome in mice on a high-fat diet

Funding LMW, FMC, CG, ACM and C-DM were funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS). FHM was supported by an EASTBIO DTP BBSRC studentship. DS was supported by a SULSA studentship.Peer reviewedPublisher PD

Maintenance with 5-FU/LV-aflibercept after induction with FOLFIRI-aflibercept versus FOLFIRI-aflibercept until progression as second-line treatment in older adults with metastatic colorectal cancer: the AFEMA phase II randomized trial

Background: The combination chemotherapy i.v. 5-fluorouracil (5-FU), irinotecan, and aflibercept (FOLFIRI-A) is a standard second-line treatment of metastatic colorectal cancer (mCRC). The aim was to assess maintenance treatment in second-line setting in older patients (aged ≥70 years) with mCRC. Patients and methods: We evaluated FOLFIRI-A given for six cycles followed by maintenance with 5-FU/leucovorin (LV)-A (arm A) or FOLFIRI-A (arm B) until progression in older adults with mCRC in the AFEMA randomized, open-label, non-inferiority phase II trial (EudraCT2016-004076-21/NCT03279289). Patients aged ≥70 years who previously failed oxaliplatin-fluoropyrimidine were randomly allocated (1 : 1) to either arm A (experimental) or arm B (control). After enrolling 35 patients, the FOLFIRI dose was reduced to level 1 in both arms due to toxicity. The primary endpoint was median progression-free survival (PFS); and secondary endpoints were median overall survival, objective response rate, and safety. Non-inferiority required the upper confidence interval (CI) limit to not exceed a hazard ratio (HR) of 1.5 (one-sided α = 0.075, 80% power). Results: A total of 170 patients were randomly allocated to arm A or arm B (n = 85 each). The median follow-up was 12.2 versus 10.9 months in arm A versus arm B. Most patients died (83.5% versus 88.2% in arm A versus arm B), mainly from disease progression. PFS non-inferiority was met (HR = 0.78, 95% CI 0.566-1.076, P = 0.131) with a median PFS of 6.1 versus 5.5 months in arm A versus arm B. Median overall survival was similar in arms A and B (12.2 and 11.5 months, respectively) (HR = 0.89, 95% CI 0.640-1.227, P = 0.467). During the maintenance phase, severe asthenia (4.5% versus 21.6%, P = 0.038), serious adverse events (SAEs) (17.8% versus 37.8%, P = 0.049), and treatment-related SAEs (6.7% versus 10.8%, P = 0.695) were reduced in arm A versus arm B. Conclusion: In older adults, induction with six cycles of FOLFIRI-A plus maintenance with 5-FU/LV-A was non-inferior to FOLFIRI-A until progression. Severe asthenia, SAEs, and treatment-related SAEs were reduced with 5-FU/LV-A maintenance.Funding: This work was supported by Spanish Cooperative Group for the Treatment of Digestive Tumors (TTD) (TTD Group), through an unrestricted grant provided by Sanofi (no grant number) Acknowledgments: The authors thank to all the investigators of the AFEMA study. The authors also thank the Spanish Cooperative Group for the Treatment of Digestive Tumors (TTD): Inmaculada Ruiz de Mena and Susana Rodríguez. Manuscript writing support was provided by Montse Sabaté-Pina, PhD from TF

A Novel Bocavirus Associated with Acute Gastroenteritis in Australian Children

Acute gastroenteritis (AGE) is a common illness affecting all age groups worldwide, causing an estimated three million deaths annually. Viruses such as rotavirus, adenovirus, and caliciviruses are a major cause of AGE, but in many patients a causal agent cannot be found despite extensive diagnostic testing. Proposing that novel viruses are the reason for this diagnostic gap, we used molecular screening to investigate a cluster of undiagnosed cases that were part of a larger case control study into the etiology of pediatric AGE. Degenerate oligonucleotide primed (DOP) PCR was used to non-specifically amplify viral DNA from fecal specimens. The amplified DNA was then cloned and sequenced for analysis. A novel virus was detected. Elucidation and analysis of the genome indicates it is a member of the Bocavirus genus of the Parvovirinae, 23% variant at the nucleotide level from its closest formally recognized relative, the Human Bocavirus (HBoV), and similar to the very recently proposed second species of Bocavirus (HBoV2). Fecal samples collected from case control pairs during 2001 for the AGE study were tested with a bocavirus-specific PCR, and HBoV2 (sequence confirmed) was detected in 32 of 186 cases with AGE (prevalence 17.2%) compared with only 15 controls (8.1%). In this same group of children, HBoV2 prevalence was exceeded only by rotavirus (39.2%) and astrovirus (21.5%) and was more prevalent than norovirus genogroup 2 (13.4%) and adenovirus (4.8%). In a univariate analysis of the matched pairs (McNemar's Test), the odds ratio for the association of AGE with HBoV2 infection was 2.6 (95% confidence interval 1.2–5.7); P = 0.007. During the course of this screening, a second novel bocavirus was detected which we have designated HBoV species 3 (HBoV3). The prevalence of HBoV3 was low (2.7%), and it was not associated with AGE. HBoV2 and HBoV3 are newly discovered bocaviruses, of which HBoV2 is the thirdmost-prevalent virus, after rotavirus and astrovirus, associated with pediatric AGE in this study

Maintenance with 5-FU/LV-aflibercept after induction with FOLFIRI-aflibercept versus FOLFIRI-aflibercept until progression as second-line treatment in older adults with metastatic colorectal cancer : the AFEMA phase II randomized trial

Background: The combination chemotherapy i.v. 5-fluorouracil (5-FU), irinotecan, and aflibercept (FOLFIRI-A) is a standard second-line treatment of metastatic colorectal cancer (mCRC). The aim was to assess maintenance treatment in second-line setting in older patients (aged ≥70 years) with mCRC. Patients and methods: We evaluated FOLFIRI-A given for six cycles followed by maintenance with 5-FU/leucovorin (LV)-A (arm A) or FOLFIRI-A (arm B) until progression in older adults with mCRC in the AFEMA randomized, open-label, non-inferiority phase II trial (EudraCT2016-004076-21/NCT03279289). Patients aged ≥70 years who previously failed oxaliplatin-fluoropyrimidine were randomly allocated (1 : 1) to either arm A (experimental) or arm B (control). After enrolling 35 patients, the FOLFIRI dose was reduced to level 1 in both arms due to toxicity. The primary endpoint was median progression-free survival (PFS); and secondary endpoints were median overall survival, objective response rate, and safety. Non-inferiority required the upper confidence interval (CI) limit to not exceed a hazard ratio (HR) of 1.5 (one-sided α = 0.075, 80% power). Results: A total of 170 patients were randomly allocated to arm A or arm B (n = 85 each). The median follow-up was 12.2 versus 10.9 months in arm A versus arm B. Most patients died (83.5% versus 88.2% in arm A versus arm B), mainly from disease progression. PFS non-inferiority was met (HR = 0.78, 95% CI 0.566-1.076, P = 0.131) with a median PFS of 6.1 versus 5.5 months in arm A versus arm B. Median overall survival was similar in arms A and B (12.2 and 11.5 months, respectively) (HR = 0.89, 95% CI 0.640-1.227, P = 0.467). During the maintenance phase, severe asthenia (4.5% versus 21.6%, P = 0.038), serious adverse events (SAEs) (17.8% versus 37.8%, P = 0.049), and treatment-related SAEs (6.7% versus 10.8%, P = 0.695) were reduced in arm A versus arm B. Conclusion: In older adults, induction with six cycles of FOLFIRI-A plus maintenance with 5-FU/LV-A was non-inferior to FOLFIRI-A until progression. Severe asthenia, SAEs, and treatment-related SAEs were reduced with 5-FU/LV-A maintenance

Detection of Aggregation-Competent Tau in Neuron-Derived Extracellular Vesicles

Progressive cerebral accumulation of tau aggregates is a defining feature of Alzheimer’s disease (AD). A popular theory that seeks to explain the apparent spread of neurofibrillary tangle pathology proposes that aggregated tau is passed from neuron to neuron. Such a templated seeding process requires that the transferred tau contains the microtubule binding repeat domains that are necessary for aggregation. While it is not clear how a protein such as tau can move from cell to cell, previous reports have suggested that this may involve extracellular vesicles (EVs). Thus, measurement of tau in EVs may both provide insights on the molecular pathology of AD and facilitate biomarker development. Here, we report the use of sensitive immunoassays specific for full-length (FL) tau and mid-region tau, which we applied to analyze EVs from human induced pluripotent stem cell (iPSC)-derived neuron (iN) conditioned media, cerebrospinal fluid (CSF), and plasma. In each case, most tau was free-floating with a small component inside EVs. The majority of free-floating tau detected by the mid-region assay was not detected by our FL assays, indicating that most free-floating tau is truncated. Inside EVs, the mid-region assay also detected more tau than the FL assay, but the ratio of FL-positive to mid-region-positive tau was higher inside exosomes than in free solution. These studies demonstrate the presence of minute amounts of free-floating and exosome-contained FL tau in human biofluids. Given the potential for FL tau to aggregate, we conclude that further investigation of these pools of extracellular tau and how they change during disease is merited