Nonenveloped Avian Reoviruses Released with Small Extracellular Vesicles Are Highly Infectious

Vesicle-encapsulated nonenveloped viruses are a recently recognized alternate form of nonenveloped viruses that can avoid immune detection and potentially increase systemic transmission. Avian orthoreoviruses (ARVs) are the leading cause of various disease conditions among birds and poultry. However, whether ARVs use cellular vesicle trafficking routes for egress and cell-to-cell transmission is still poorly understood. We demonstrated that fusogenic ARV-infected quail cells generated small (~100 nm diameter) extracellular vesicles (EVs) that contained electron-dense material when observed by transmission electron microscope. Cryo-EM tomography indicated that these vesicles did not contain ARV virions or core particles, but the EV fractions of OptiPrep gradients did contain a small percent of the ARV virions released from cells. Western blotting of detergent-treated EVs revealed that soluble virus proteins and the fusogenic p10 FAST protein were contained within the EVs. Notably, virus particles mixed with the EVs were up to 50 times more infectious than virions alone. These results suggest that EVs and perhaps fusogenic FAST-EVs could contribute to ARV virulence.

Null results of oxytocin and vasopressin administration across a range of social cognitive and behavioral paradigms: Evidence from a randomized controlled trial

Research examining oxytocin and vasopressin in humans has the potential to elucidate neurobiological mechanisms underlying human sociality that have been previously unknown or not well characterized. A primary goal of this work is to increase our knowledge about neurodevelopmental and psychiatric disorders characterized by impairments in social cognition. However, years of research highlighting wide-ranging effects of, in particular, intranasal oxytocin administration have been tempered as the fields of psychology, neuroscience, and other disciplines have been addressing concerns over the reproducibility and validity of research findings. We present a series of behavioral tasks that were conducted using a randomized, double-blind, placebo controlled, between-subjects design, in which our research group found no main effects of oxytocin and vasopressin on a host of social outcomes. In addition to null hypothesis significance testing, we implemented equivalence testing and Bayesian hypothesis testing to examine the sensitivity of our findings. These analyses indicated that 47-83% of our results (depending on the method of post-hoc analysis) had enough sensitivity to detect the absence of a main effect. Our results add to evidence that intranasal oxytocin may have a more limited direct effect on human social processes than initially assumed and suggest that the direct effects of intranasal vasopressin may be similarly limited. Randomized controlled trial registration: NCT01680718.

Oxytocin, but not vasopressin, impairs social cognitive ability among individuals with higher levels of social anxiety: a randomized controlled trial

Individuals with social anxiety are characterized by a high degree of social sensitivity, which can coincide with impairments in social cognitive functioning (e.g. theory of mind). Oxytocin (OT) and vasopressin (AVP) have been shown to improve social cognition, and OT has been theorized as a potential therapeutic agent for individuals with social anxiety disorder. However, no study has investigated whether these neuropeptides improve social cognitive ability among socially anxious individuals. In a randomized, double-blind, placebo controlled, between-subjects design we investigated whether social anxiety moderated the effects of OT or AVP (vs placebo) on social working memory (i.e. working memory that involves manipulating social information) and non-social working memory. OT vs placebo impaired social working memory accuracy in participants with higher levels of social anxiety. No differences were found for non-social working memory or for AVP vs placebo. Results suggest that OT administration in individuals with higher levels of social anxiety may impair social cognitive functioning. Randomized-controlled trial registration: NCT01680718.

Vasopressin, but not oxytocin, increases empathic concern among individuals who received higher levels of paternal warmth: A randomized controlled trial

BACKGROUND

Empathy improves our ability to communicate in social interactions and motivates prosocial behavior. The neuropeptides arginine vasopressin and oxytocin play key roles in socioemotional processes such as pair bonding and parental care, which suggests that they may be involved in empathic processing.

METHODS

We investigated how vasopressin and oxytocin affect empathic responding in a randomized, double-blind, placebo controlled, between-subjects study design. We also examined the moderating role of parental warmth, as reported in the early family environment, on empathic responding following vasopressin, oxytocin, or placebo administration.

RESULTS

Among participants who reported higher levels of paternal warmth (but not maternal warmth), vasopressin (vs. placebo and oxytocin) increased ratings of empathic concern after viewing distressing and uplifting videos. No main or interaction effects were found for individuals who received oxytocin.

CONCLUSIONS

Vasopressin has a role in enhancing empathy among individuals who received higher levels of paternal warmth.

TRIAL REGISTRATION

NCT01680718.

Moderate threat causes longer lasting disruption to processing in anxious individuals

Anxiety is associated with increased attentional capture by threat. Previous studies have used simultaneous or briefly separated (<1 s) presentation of threat distractors and target stimuli. Here, we tested the hypothesis that high trait anxious participants would show a longer time window within which distractors cause disruption to subsequent task processing, and that this would particularly be observed for stimuli of moderate or ambiguous threat value. A novel temporally separated emotional distractor task was used. Face or house distractors were presented for 250 ms at short (∼1.6 s) or long (∼3 s) intervals prior to a letter string comprising Xs or Ns. Trait anxiety was associated with slowed identification of letter strings presented at long intervals after face distractors with part surprise/part fear expressions. In other words, these distractors had an impact on high anxious individuals’ speed of target identification seconds after their offset. This was associated with increased activity in the fusiform gyrus and amygdala and reduced dorsal anterior cingulate recruitment. This pattern of activity may reflect impoverished recruitment of reactive control mechanisms to damp down stimulus-specific processing in subcortical and higher visual regions. These findings have implications for understanding how threat-related attentional biases in anxiety may lead to dysfunction in everyday settings where stimuli of moderate, potentially ambiguous, threat value such as those used here are fairly common, and where attentional disruption lasting several seconds may have a profound impact.

Unraveling the anxious mind: anxiety, worry, and frontal engagement in sustained attention versus off-task processing

Much remains unknown regarding the relationship between anxiety, worry, sustained attention, and frontal function. Here, we addressed this using a sustained attention task adapted for functional magnetic resonance imaging. Participants responded to presentation of simple stimuli, withholding responses to an infrequent “No Go” stimulus. Dorsolateral prefrontal cortex (DLPFC) activity to “Go” trials, and dorsal anterior cingulate (dACC) activity to “No Go” trials were associated with faster error-free performance; consistent with DLPFC and dACC facilitating proactive and reactive control, respectively. Trait anxiety was linked to reduced recruitment of these regions, slower error-free performance, and decreased frontal-thalamo-striatal connectivity. This indicates an association between trait anxiety and impoverished frontal control of attention, even when external distractors are absent. In task blocks where commission errors were made, greater DLPFC-precuneus and DLPFC-posterior cingulate connectivity were associated with both trait anxiety and worry, indicative of increased off-task thought. Notably, unlike trait anxiety, worry was not linked to reduced frontal-striatal-thalamo connectivity, impoverished frontal recruitment, or slowed responding during blocks without commission errors, contrary to accounts proposing a direct causal link between worry and impoverished attentional control. This leads us to propose a new model of the relationship between anxiety, worry and frontal engagement in attentional control versus off-task thought.

An fMRI study of caring vs self-focus during induced compassion and pride

This study examined neural activation during the experience of compassion, an emotion that orients people toward vulnerable others and prompts caregiving, and pride, a self-focused emotion that signals individual strength and heightened status. Functional magnetic resonance images (fMRI) were acquired as participants viewed 55 s continuous sequences of slides to induce either compassion or pride, presented in alternation with sequences of neutral slides. Emotion self-report data were collected after each slide condition within the fMRI scanner. Compassion induction was associated with activation in the midbrain periaqueductal gray (PAG), a region that is activated during pain and the perception of others' pain, and that has been implicated in parental nurturance behaviors. Pride induction engaged the posterior medial cortex, a region that has been associated with self-referent processing. Self-reports of compassion experience were correlated with increased activation in a region near the PAG, and in the right inferior frontal gyrus (IFG). Self-reports of pride experience, in contrast, were correlated with reduced activation in the IFG and the anterior insula. These results provide preliminary evidence towards understanding the neural correlates of important interpersonal dimensions of compassion and pride. Caring (compassion) and self-focus (pride) may represent core appraisals that differentiate the response profiles of many emotions.

Description of a procedure which allows isolation of viral nonstructural proteins from BHK vertebrate cells infected with the West Nile flavivirus in a state which allows their direct chemical characterization

We have developed a procedure which allows isolation of virus-coded nonstructural (NS) proteins from BHK cells infected with the West Nile (WN) flavivirus in a state of purity which allows their chemical characterization. A crude membrane fraction proved to be a suitable starting material. Incubation of crude membranes in buffer containing 1.2 M guanidine hydrochloride (GH) allows isolation of weakly washed membranes. Incubation of weakly washed membranes in the presence of either 5 M GH or 8 M urea allows the isolation of stringently washed membranes, as well as a soluble protein-containing wash which is called the differential wash. Stringently washed membranes contain proteins with apparent molecular weights of 14, 19, 23, 29, and 50 kDa as predominant constituents. These proteins are of sufficient purity after SDS-PAGE to allow amino-terminal sequence determination. Together with the genome RNA sequence these analyses show that these molecules represent the virus-coded proteins NS 2b, NS 2a, pre M, NS 4b, and E, respectively. Similar analysis of the proteins present in the differential wash shows that the proteins NS 5, NS 3, and NS 1 are major constituents of this material. The carboxy-terminal sequences of NS 5 and NS 1 have also been determined.

Nucleotide sequence of the 5'-terminal untranslated part of the genome of the flavivirus West Nile virus

We have determined the nucleotide sequence of the 5'-terminal untranslated region of the 42 S genome RNA of the flavivirus West Nile virus by primer extension. These analyses make our primary structure determination of this genome, which comprises a total number of 10,960 nucleotides, complete. Some implications of our data concerning the structure of flavivirus-specific nucleic acids and the initiation of translation of WN virus-specific RNA are discussed.

Analysis of structural properties which possibly are characteristic for the 3'-terminal sequence of the genome RNA of flaviviruses

Recently we have shown that an open reading frame comprising 10290 nucleotides is present on the infectious, single-stranded genome RNA of the West Nile flavivirus. We have now isolated cloned cDNA representing the 3'-terminal untranslated region of this molecule. The sequence of this region which comprises 571 nucleotides is given in this report. Recently, the nucleotide sequence of the genome RNA of the yellow fever flavivirus has been described. A comparative analysis of the 3'-terminal untranslated nucleotide sequences present in each genome suggests that in flaviviruses this region probably has the following properties. It has a heteropolymeric sequence at the 3' terminus. It contains one or more oligonucleotide sequences that are repeated. An extensive stem and loop structure can be folded from the nucleotide sequences present at the 3' terminus. The stem of this structure contains a conserved region introducing a defined mismatch into the stem. The loop of this structure probably contains short conserved oligonucleotide sequences in analogous positions. In both viruses the oligonucleotide CAUAUUGAC (AG)CC(UA) GGGA(UA) AGAC lies closely in front of the sequence which can be folded into the stem of the 3'-terminal stem and loop structure and the oligonucleotide CUAGAGGUUAGAGGAGACCC is strictly conserved between both viruses. The analyses indicate that the 3'-terminal untranslated region of the genome of flaviviruses probably has rather unique characteristics of primary and secondary structure. Possible implications of these findings are discussed.

Primary structure of the West Nile flavivirus genome region coding for all nonstructural proteins

The genome RNA of the flavivirus West Nile (WN) virus has been transcribed into cDNA, the cDNA has been cloned, and the nucleotide sequences coding for the structural proteins have been determined (Castle et al., 1985; Wengler et al., 1985). We have now determined the nucleotide sequence coding for all viral nonstructural proteins which comprises 7929 nucleotides. Together with our earlier sequence analyses these data show that a long open reading frame (ORF) containing 10,290 nucleotides is present on the genome of WN virus. The two largest nonstructural proteins which can be detected in flavivirus-infected cells are the proteins NV5 and NV4 which have an apparent molecular mass of 97,000 and 74,000 Da, respectively. Both proteins were isolated by preparative polyacrylamide gel electrophoresis, and partial amino acid sequences of peptides derived from these proteins were determined. These analyses allow us to localize the nucleotide regions which code for these proteins and show that the region coding for the NV5 protein is located at the 3'-terminus of the long ORF. Together with our earlier analyses these data show that the protein sequences of virus-specific proteins are present on the viral polyprotein translated from the long ORF in the order V2-NV2-V3-(nonstructural proteins of up to 75,000 Da)-NV4-(nonstructural proteins of up to 45,000 Da)-NV5. Our data indicate that virus-specific structural and nonstructural proteins which are synthesized from a single long ORF accumulate in large amounts in infected cells. A possible role of the presence of these molecules, which are associated to cellular membranes, in the accumulation of membrane vesicles which characteristically occurs in flavivirus-infected cells is discussed.

Sequence analysis of the membrane protein V3 of the flavivirus West Nile virus and of its gene

Flaviviruses contain a large membrane-associated protein V3, having a mol mass of about 50 kDa which is responsible for hemagglutination. We have isolated the V3 protein from the West Nile (WN) flavivirus and determined its amino-terminal amino acid sequence and amino acid sequences of fragments derived from this protein. We have also transcribed parts of the WN virus genome RNA into cDNA and cloned and sequenced this cDNA. The results of these analyses have allowed us to identify the region of the viral genome coding for the V3 protein. In this report we describe the total nucleotide sequence of the genome region coding for the WN virus V3 protein and the amino acid sequence of the V3 protein derived from these analyses. The exact carboxy terminus of the V3 protein has not been determined in these experiments. These analyses have shown that the V3 protein of WN virus does not contain an Asn-X-Ser/Thr sequence which could allow addition of N-linked carbohydrate chains to this protein. In accordance with this finding, analyses of metabolic labeling of the V3 protein using [3H]glucosamine indicate that the WN virus V3 protein is an unglycosylated protein. Together with our earlier analyses these results show that the viral structural proteins are present on the genome RNA in the order 5'-terminus-core protein (V2)-small membrane-associated protein (NV2)-large membrane-associated protein (V3) and describe the nucleotide sequences coding for all WN virus structural proteins identified so far. A hypothesis concerning the processes involved in the synthesis of all viral structural proteins and the probable orientation of these proteins relative to the endoplasmatic reticulum membrane based on the structure of these proteins is discussed.

Sequence analysis of the viral core protein and the membrane-associated proteins V1 and NV2 of the flavivirus West Nile virus and of the genome sequence for these proteins

Cell-associated flaviviruses contain the two membrane proteins V3 and NV2 besides the viral core protein V2 whereas extracellular viruses do contain V2 protein and the two membrane proteins V3 and V1. Since the V1 protein could not be detected in infected cells it has been suggested that V1 is generated from NV2 by proteolytic cleavage during the release of virus from cells (D. Shapiro, W. E. Brandt, and P. K. Russell (1972), Virology 50, 906-911). We have isolated the viral structural proteins V1, V2, and NV2 from the flavivirus West Nile virus and determined their amino-terminal amino acid sequences and amino acid sequences of peptides derived from these proteins. We have also transcribed parts of the viral genome into cDNA and cloned and sequenced this cDNA. The analyses of the protein structure of V1, V2, and NV2 together with the determination of the amino-terminal sequence of V3 (data not shown) have allowed us to identify the nucleotide region coding for the structural proteins V2, NV2, and V1. The primary structure of this nucleotide sequence is presented in this report. The data show that the amino terminus of the viral core protein V2 is followed by the amino termini of the proteins NV2, V1, and V3, respectively. These data for the first time identify the exact order of all structural proteins of a flavivirus identified so far. Our data strongly support the above-mentioned hypothesis that V1 is derived from NV2 by proteolytic cleavage and furthermore indicate that V1 represents the nonglycosylated carboxy-terminal part of NV2 which contains those sequences which anchor NV2 in the viral membrane. A working hypothesis is presented in which two species of cellular enzymes, signalase(s) removing signal sequences and enzymes involved in cleaving polyproteins after a pair of basic amino acids, do generate the proteins V2, NV2, and V1 from the growing peptide chain synthesized during translation of the 42 S genome RNA which functions as mRNA for these proteins.