Deformed wing virus genotypes A and B do not elicit immunologically different responses in naïve honey bee hosts.

Iflavirus aladeformis (Picornavirales: Iflaviridae), commonly known as deformed wing virus(DWV), in association with Varroa destructor Anderson and Trueman (Mesostigmata: Varroidae), is a leading factor associated with honey bee (Apis mellifera L. [Hymenoptera: Apidae]) deaths. The virus and mite have a near global distribution, making it difficult to separate the effect of one from the other. The prevalence of two main DWV genotypes (DWV-A and DWV-B) has changed over time, leading to the possibility that the two strains elicit a different immune response by the host. Here, we use a honey bee population naïve to both the mite and the virus to investigate if honey bees show a different immunological response to DWV genotypes. We examined the expression of 19 immune genes by reverse transcription quantitative PCR (RT-qPCR) and analysed small RNA after experimental injection with DWV-A and DWV-B. We found no evidence that DWV-A and DWV-B elicit different immune responses in honey bees. RNA interference genes were up-regulated during DWV infection, and small interfering RNA (siRNA) responses were proportional to viral loads yet did not inhibit DWV accumulation. The siRNA response towards DWV was weaker than the response to another honey bee pathogen, Triatovirus nigereginacellulae (Picornavirales: Dicistroviridae; black queen cell virus), suggesting that DWV is comparatively better at evading host antiviral defences. There was no evidence for the production of virus-derived Piwi-interacting RNAs (piRNAs) in response to DWV. In contrast to previous studies, and in the absence of V. destructor, we found no evidence that DWV has an immunosuppressive effect. Overall, our results advance our understanding of the immunological effect that DWV in isolation elicits in honey bees.

Abundant small RNAs in the reproductive tissues and eggs of the honey bee, Apis mellifera.

BACKGROUND: Polyandrous social insects such as the honey bee are prime candidates for parental manipulation of gene expression in offspring. Although there is good evidence for parent-of-origin effects in honey bees the epigenetic mechanisms that underlie these effects remain a mystery. Small RNA molecules such as miRNAs, piRNAs and siRNAs play important roles in transgenerational epigenetic inheritance and in the regulation of gene expression during development. RESULTS: Here we present the first characterisation of small RNAs present in honey bee reproductive tissues: ovaries, spermatheca, semen, fertilised and unfertilised eggs, and testes. We show that semen contains fewer piRNAs relative to eggs and ovaries, and that piRNAs and miRNAs which map antisense to genes involved in DNA regulation and developmental processes are differentially expressed between tissues. tRNA fragments are highly abundant in semen and have a similar profile to those seen in the semen of other animals. Intriguingly we also find abundant piRNAs that target the sex determination locus, suggesting that piRNAs may play a role in honey bee sex determination. CONCLUSIONS: We conclude that small RNAs may play a fundamental role in honey bee gametogenesis and reproduction and provide a plausible mechanism for parent-of-origin effects on gene expression and reproductive physiology.

Simultaneous Isolation of High-Quality RNA and DNA From Postmortem Human Central Nervous System Tissues for Omics Studies.

Multi-omics approaches are increasingly being adopted to understand the complex networks underlying disease. The coisolation of high-quality nucleotides from affected tissues is paramount for the parallel analysis of transcriptomic, genomic, and epigenomic data sets. Although nucleotides extracted from postmortem central nervous system (CNS) tissue are widely used in the study of neurodegenerative disease, assessment of methods for the simultaneous isolation of DNA and RNA is limited. Herein, we describe a strategy for the isolation of high-quality DNA and RNA from postmortem human tissue from 7 CNS regions. Motor cortex, frontal cortex, hippocampus, occipital cortex, anterior cingulate cortex, cerebellum, and spinal cord tissues were obtained from 22 individuals diagnosed with motor neuron disease (MND) and 13 neurologically normal controls (n = 245 tissues). We demonstrated that the Qiagen AllPrep DNA/RNA kit consistently isolated DNA and RNA of high yield and quality from all 6 brain regions. Importantly, phenol-chloroform-based extraction was required to isolate high-yield RNA from spinal cord. RNA sequencing using RNA extracted from 6 CNS regions (n = 60) generated high-quality transcriptomes. Hierarchical clustering of data from motor cortex, using an MND susceptibility gene panel and marker genes of disease-associated microglia, demonstrated that MND-specific gene expression signatures could be detected in the transcriptome data.

Riluzole does not ameliorate disease caused by cytoplasmic TDP-43 in a mouse model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease commonly treated with riluzole, a small molecule that may act via modulation of glutamatergic neurotransmission. However, riluzole only modestly extends lifespan for people living with ALS, and its precise mechanisms of action remain unclear. Most ALS cases are characterised by accumulation of cytoplasmic TAR DNA binding protein of 43 kDa (TDP-43), and understanding the effects of riluzole in models that closely recapitulate TDP-43 pathology may provide insights for development of improved therapeutics. We therefore investigated the effects of riluzole in female transgenic mice that inducibly express nuclear localisation sequence (NLS)-deficient human TDP-43 in neurons (NEFH-tTA/tetO-hTDP-43ΔNLS, 'rNLS8', mice). Riluzole treatment from the first day of hTDP-43ΔNLS expression did not alter disease onset, weight loss or performance on multiple motor behavioural tasks. Riluzole treatment also did not alter TDP-43 protein levels, solubility or phosphorylation. Although we identified a significant decrease in GluA2 and GluA3 proteins in the cortex of rNLS8 mice, riluzole did not ameliorate this disease-associated molecular phenotype. Likewise, riluzole did not alter the disease-associated atrophy of hindlimb muscle in rNLS8 mice. Finally, riluzole treatment beginning after disease onset in rNLS8 mice similarly had no effect on progression of late-stage disease or animal survival. Together, we demonstrate specific glutamatergic receptor alterations and muscle fibre-type changes reminiscent of ALS in female rNLS8 mice, but riluzole had no effect on these or any other disease phenotypes. Future targeting of pathways related to accumulation of TDP-43 pathology may be needed to develop better treatments for ALS.

Interrogating the Relationship Between Schizotypy, the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism, and Neuronal Oscillatory Activity.

The COMT Val158Met polymorphism affects the availability of synaptic dopamine in the prefrontal cortex and has been widely studied as a genetic risk factor for psychosis. Schizotypy is associated with an increased risk of psychosis, with some studies implicating similar neurobiological mechanisms to schizophrenia. The present study sought to interrogate the link between the COMT Val158Met polymorphism and schizotypy using electroencephalogram (EEG) to identify neurophysiological mechanisms underpinning psychosis risk. Neurotypical (N = 91) adults were genotyped for the COMT Val158Met polymorphism, completed the Schizotypal Personality Questionnaire (SPQ), and had eyes open resting-state EEG recorded for 4 min. SPQ suspiciousness subscale scores were higher for individuals homozygous for Val/Val and Met/Met versus Val/Met genotypes. Delta, theta, alpha-2, beta-1, and beta-2 amplitudes were lower for Val/Val than Met/Met individuals. Lower theta amplitudes were correlated with higher total SPQ scores (P = 0.050), and multiple regression revealed that higher delta, and lower theta and beta-2 amplitudes (but not COMT genotype) best predicted total SPQ scores (P = 0.014). This study demonstrates the importance of COMT genotype in determining trait suspiciousness and EEG oscillatory activity. It also highlights relationships between dopaminergic alterations, EEG and schizotypy that are dissimilar to those observed in schizophrenia.