Antiviral Immunity in the Fruit Fly, Drosophila melanogaster

The fruit fly, Drosophila melanogaster, is an extremely useful model to study innate immunity mechanisms. A fundamental understanding of these mechanisms as they relate to various pathogens has come to light over the past 30 years. The discovery of Toll‐like receptors and their recognition of shared molecules (pathogen‐associated molecular patterns or PAMPs) among pathogenic bacteria were the first detailed set of receptors to be described that act in innate immunity. The immune deficiency pathway (Imd) described in D. melanogaster functions in a very similar way to the Toll pathway in recognizing PAMPs primarily from Gram‐negative bacteria. The discovery of small interfering RNAs (RNAi) provided a means by which antiviral immunity was accomplished in invertebrates. Another related pathway, the JAK/STAT pathway, functions in a similar manner to the interferon pathways described in vertebrates, also providing antiviral defense. Recently, autophagy was also shown to function as a protective pathway against virus infection in D. melanogaster. At least three of these pathways (Imd, JAK/STAT, and RNAi) show signal integration in response to viral infection, demonstrating a coordinated immune response against viral infection. The number of pathways and the integration of them reflect the diversity of pathogens to which innate immune mechanisms must be able to respond. The viral pathogens that infect invertebrates have developed countermeasures to some of these pathways, in particular to RNAi. The evolutionary arms race of pathogen vs. host is ever ongoing

Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts of \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

Aging is a complex process characterized by a steady decline in an organism’s ability to perform life-sustaining tasks. In the present study, two cages of approximately 12,000 mated Drosophila melanogaster females were used as a source of RNA from individuals sampled frequently as a function of age. A linear model for micro array data method was used for the micro array analysis to adjust for the box effect; it identified 1,581 candidate aging genes.Cluster analyses using a self-organizing map algorithm on the 1,581 significant genes identified gene expression patterns across different ages. Genes involved in immune system function and regulation, chorion assembly and function, and metabolism were all significantly differentially expressed as a function of age. The temporal pattern of data indicated that gene expression related to aging is affected relatively early in life span. In addition, the temporal variance in gene expression in immune function genes was compared to a random set of genes. There was an increase in the variance of gene expression within each cohort, which was not observed in the set of random genes.This observation is compatible with the hypothesis that D. melanogaster immune function genes lose control of gene expression as flies age

Analysis of immune-related genes during Nora virus infection of <em>Drosophila melanogaster</em> using next generation sequencing

Drosophila melanogaster depends upon the innate immune system to regulate and combat viral infection. This is a complex, yet widely conserved process that involves a number of immune pathways and gene interactions. In addition, expression of genes involved in immunity are differentially regulated as the organism ages. This is particularly true for viruses that demonstrate chronic infection, as is seen with Nora virus. Nora virus is a persistent non-pathogenic virus that replicates in a horizontal manner in D. melanogaster. The genes involved in the regulation of the immune response to Nora virus infection are largely unknown. In addition, the temporal response of immune response genes as a result of infection has not been examined. In this study, D. melanogaster either infected with Nora virus or left uninfected were aged for 2, 10, 20 and 30 days. The RNA from these samples was analyzed by next generation sequencing (NGS) and the resulting immune-related genes evaluated by utilizing both the PANTHER and DAVID databases, as well as comparison to lists of immune related genes and FlyBase. The data demonstrate that Nora virus infected D. melanogaster exhibit an increase in immune related gene expression over time. In addition, at day 30, the data demonstrate that a persistent immune response may occur leading to an upregulation of specific immune response genes. These results demonstrate the utility of NGS in determining the potential immune system genes involved in Nora virus replication, chronic infection and involvement of antiviral pathways

Screening for psychological distress in patients with lung cancer: results of a clinical audit evaluating the use of the patient Distress Thermometer

Patients with lung cancer frequently suffer psychological distress and guidelines in the United Kingdom recommend screening of all cancer patients for this problem. The audit investigated use of the Distress Thermometer in terms of staff adherence to locally developed guidelines, patient willingness to use the tool, its impact on referral rates to clinical psychology services and concordance between the tool and the clinical assessment. Use of the Distress Thermometer was audited over a 3-month period in one lung cancer outpatient clinic. Referrals to clinical psychology services in response to clearly delineated referral indicators were assessed. Patient-reported outcomes were compared with practitioner assessment of need during clinical consultations to see whether the tool was measuring distress effectively. Thirty three of 34 patients used the Distress Thermometer during the audit period. Ten reported distress levels above 4 in the emotional or family problems domains. On ten occasions, the clinical interview identified problems not elicited by the Distress Thermometer. Guidelines were adhered to by staff, and patients were offered information about local support services and referral to clinical psychology services where indicated. Whilst all patients were happy to receive written information about further sources of support, none wanted to be referred to psychological services at that time. The Distress Thermometer is acceptable to patients with lung cancer in outpatient settings but it did not increase referrals for psychological support. Staff found it to be a useful tool in opening up communication about patient issues although it should not replace a comprehensive clinical interview

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Characterization of Nora Virus Structural Proteins via Western Blot Analysis

Nora virus is a single stranded RNA picorna-like virus with four open reading frames (ORFs). The coding potentials of the ORFs are not fully characterized, but ORF3 and ORF4 are believed to encode the capsid proteins (VP3, VP4a, VP4b, and VP4c) comprising the virion. To determine the polypeptide composition of Nora virus virions, polypeptides from purified virus were compared to polypeptides detected in Nora virus infected Drosophila melanogaster. Nora virus was purified from infected flies and used to challenge mice for the production of antisera. ORF3, ORF4a, ORF4b, and ORF4c were individually cloned and expressed in E. coli; resultant recombinant proteins purified and were used to make monospecific antisera. Antisera were evaluated via Western blot against whole virus particles and Nora virus infected fly lysates. Viral purification yielded two particle types with densities of ~1.31 g/mL (empty particles) and ~1.33 g/mL (complete virions). Comparison of purified virus polypeptide composition to Nora virus infected D. melanogaster lysate showed the number of proteins in infected cell lysates is less than purified virus. Our results suggest the virion is composed of 6 polypeptides, VP3, VP4a, two forms of VP4b, and two forms of VP4c. This polypeptide composition is similar to other small RNA insect viruses

Nora Virus VP4b and ORF1 Circulate in Hemolymph of Infected D. melanogaster with Coordinate Expression of Vago and Vir-1

Study of the novel RNA virus, Nora virus, which is a persistent, picorna-like virus that replicates in the gut of Drosophila melanogaster offers insight into human innate immunity and other picorna-like viruses. Nora virus infection leads to a locomotor abnormality and upregulation of two candidate target proteins, Vago and Virus-induced RNA 1 (Vir-1). These proteins are uncharacterized in response to Nora virus. We hypothesize that Nora virus is circulating in the hemolymph of Nora virus-infected D. melanogaster, allowing for migration beyond the primary site of replication in the gut. Analysis by qRT-PCR demonstrated biphasic viral load and corresponding vago and vir-1 transcription levels, suggesting transcription of vago and vir-1 occurs in response to viral infection. However, Vir-1 is also present in virus-free D. melanogaster suggesting basal expression or alternative functions. Presence of Nora virus RNA and the Viral Protein 4b (VP4b), in hemolymph of infected D. melanogaster supports the hypothesized circulation of Nora virus in the hemolymph. The study suggests that impaired locomotor function may be due to transport of Nora virus from the gut to the brain via the hemolymph

Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts of \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

Aging is a complex process characterized by a steady decline in an organism’s ability to perform life-sustaining tasks. In the present study, two cages of approximately 12,000 mated Drosophila melanogaster females were used as a source of RNA from individuals sampled frequently as a function of age. A linear model for micro array data method was used for the micro array analysis to adjust for the box effect; it identified 1,581 candidate aging genes.Cluster analyses using a self-organizing map algorithm on the 1,581 significant genes identified gene expression patterns across different ages. Genes involved in immune system function and regulation, chorion assembly and function, and metabolism were all significantly differentially expressed as a function of age. The temporal pattern of data indicated that gene expression related to aging is affected relatively early in life span. In addition, the temporal variance in gene expression in immune function genes was compared to a random set of genes. There was an increase in the variance of gene expression within each cohort, which was not observed in the set of random genes.This observation is compatible with the hypothesis that D. melanogaster immune function genes lose control of gene expression as flies age