RNA interference in honeybees : off-target effects caused by dsRNA

RNA interference involves the targeted knockdown of mRNA triggered by complementary dsRNA molecules applied to an experimental organism. Although this technique has been successfully used in honeybees (Apis mellifera), it remains unclear whether the application of dsRNA leads to unintended expression knockdown in unspecific, non-targeted genes. Therefore, we studied the gene expression of four non-target genes coding for proteins that are involved in different physiological processes after treatment with three dsRNAs in two abdominal tissues. We found unspecific gene downregulation depending on both the dsRNA used and the different tissues. Hence, RNAi experiments in the honeybee require rigid controls and carefully selected dsRNA sequences to avoid misinterpretation of RNAi-derived phenotypes.This study was financially supported by the DFG (RFAM).http://link.springer.com/journal/13592hb2016Zoology and Entomolog

Deformed wing virus and drone mating flights in the honey bee ( Apis mellifera ): implications for sexual transmission of a major honey bee virus

Deformed wing virus (DWV) represents an ideal model to study the interaction between mode of transmission and virulence in honey bees since it exhibits both horizontal and vertical transmissions. However, it is not yet clear if venereal-vertical transmission represents a regular mode of transmission for this virus in natural honey bee populations. Here, we provide clear evidence for the occurrence of high DWV titres in the endophallus of sexually mature drones collected from drone congregation areas (DCAs). Furthermore, the endophallus DWV titres of drones collected at their maternal hives were no different from drones collected at nearby DCAs, suggesting that high-titre DWV infection of the endophallus does not hinder the ability of drones to reach the mating area. The results are discussed within the context of the dispersal of DWV between colonies and the definition of DWV virulence with respect to the transmission route and the types of tissues infecte

Control of mandibular gland pheromone synthesis by alternative splicing of the CP-2 transcription factor gemini in honeybees (Apis mellifera carnica)

The honeybee queen’s mandibular gland pheromones (QMP) are essential for the suppression of worker reproduction. Worker ovary activation is regulated by alternative splicing of a CP2-transcription factor named gemini. Since workers with activated ovaries also produce QMP in their mandibular glands, we tested whether alternative splicing of gemini also controls mandibular gland pheromone biosynthesis in workers using RNA interference. Altering the splice pattern of gemini resulted in enhanced levels of the queen-specific components of the mandibular gland pheromone in queenless honeybee workers, suggesting that gemini functions as a pleiotropic regulatory switch influencing both ovary activation and resulting in QMP synthesis in workers. Because the QMP produced by these workers suppresses ovary activation in other workers, gemini seems to be a key regulatory gene affecting reproductive hierarchies among workers in queenless colonies.The Deutsche Forschungsgemeinschaft (RFAM; MO 373/30-1), the South African National Research Foundation’s (NRF) incentive funding to CWWP, RMC, and Research Career Advancement (RCA) fellowship to AAY (Grant no. 91419).http://link.springer.com/journal/135922019-08-01hj2019Zoology and Entomolog

High-intensity non-invasive ventilation during exercise-training versus without in people with very severe COPD and chronic hypercapnic respiratory failure: a randomised controlled trial

Background People with very severe chronic obstructive pulmonary disease (COPD) using nocturnal non-invasive ventilation (NIV) for chronic hypercapnic respiratory failure (CHRF) experience reduced exercise capacity and severe dyspnoea during exercise training (ET). The use of NIV during ET can personalise training during pulmonary rehabilitation (PR) but whether high-intensity NIV (HI-NIV) during exercise is accepted and improves outcomes in these extremely physically limited patients is unknown. The aim of this trial was to determine if ET with HI-NIV during PR was more effective than without at improving exercise capacity and reducing dyspnoea during exercise.Methods Patients with COPD, CHRF and nocturnal-NIV were randomised to supervised cycle-ET as part of PR with HI-NIV or without (control). Primary outcome was change in cycle endurance time (ΔCETtime), while secondary outcomes were dyspnoea at isotime during the cycle endurance test and during ET-sessions and for the HI-NIV group, post-trial preferred exercising method.Results Twenty-six participants (forced expiratory volume in 1 s 22±7%pred, PaCO251±7 mm Hg) completed the trial (HI-NIV: n=13, ET: IPAP 26±3/EPAP 6±1 cm H2O; control n=13). At completion of a 3 week ET-programme, no significant between-group differences in ΔCETtime were seen (HI-NIV-control: Δ105 s 95% CI (−92 to 302), p=0.608). Within-group ΔCETtime was significant (HI-NIV: +246 s 95% CI (61 to 432); control: +141 s 95% CI (60 to 222); all p<0.05). The number of responders (Δ>minimal important difference (MID)101 s: n=53.8%) was the same in both groups for absolute ΔCETtime and 69.2% of control and 76.9% of the HI-NIV group had a %change>MID33%.Compared with control, the HI-NIV group reported less isotime dyspnoea (Δ−2.0 pts. 95% CI (−3.2 to −0.8), p=0.005) and during ET (Δ−3.2 pts. 95% CI (−4.6 to −1.9), p<0.001). Most of the HI-NIV group (n=12/13) preferred exercising with NIV.Conclusion In this small group of patients with very severe COPD requiring nocturnal NIV, participation in an ET-programme during PR significantly improved exercise capacity irrespective of HI-NIV use. Reported dyspnoea was in favour of HI-NIV.Trial registration number NCT03803358

Targeted T cell receptor gene editing provides predictable T cell product function for immunotherapy.

Adoptive transfer of T cells expressing a transgenic T cell receptor (TCR) has the potential to revolutionize immunotherapy of infectious diseases and cancer. However, the generation of defined TCR-transgenic T cell medicinal products with predictable in vivo function still poses a major challenge and limits broader and more successful application of this "living drug." Here, by studying 51 different TCRs, we show that conventional genetic engineering by viral transduction leads to variable TCR expression and functionality as a result of variable transgene copy numbers and untargeted transgene integration. In contrast, CRISPR/Cas9-mediated TCR replacement enables defined, targeted TCR transgene insertion into the TCR gene locus. Thereby, T cell products display more homogeneous TCR expression similar to physiological T cells. Importantly, increased T cell product homogeneity after targeted TCR gene editing correlates with predictable in vivo T cell responses, which represents a crucial aspect for clinical application in adoptive T cell immunotherapy

Control of mandibular gland pheromone synthesis by alternative splicing of the CP-2 transcription factor gemini in honeybees (Apis mellifera carnica)

The honeybee queen’s mandibular gland pheromones (QMP) are essential for the suppression of worker reproduction. Worker ovary activation is regulated by alternative splicing of a CP2-transcription factor named gemini. Since workers with activated ovaries also produce QMP in their mandibular glands, we tested whether alternative splicing of gemini also controls mandibular gland pheromone biosynthesis in workers using RNA interference. Altering the splice pattern of gemini resulted in enhanced levels of the queen-specific components of the mandibular gland pheromone in queenless honeybee workers, suggesting that gemini functions as a pleiotropic regulatory switch influencing both ovary activation and resulting in QMP synthesis in workers. Because the QMP produced by these workers suppresses ovary activation in other workers, gemini seems to be a key regulatory gene affecting reproductive hierarchies among workers in queenless colonies.The Deutsche Forschungsgemeinschaft (RFAM; MO 373/30-1), the South African National Research Foundation’s (NRF) incentive funding to CWWP, RMC, and Research Career Advancement (RCA) fellowship to AAY (Grant no. 91419).http://link.springer.com/journal/135922019-08-01hj2019Zoology and Entomolog