Efficient in vitro and in vivo transfection of self-amplifying mRNA with linear poly(propylenimine) and poly(ethylenimine-propylenimine) random copolymers as non-viral carriers

Messenger RNA (mRNA) based vaccines have been introduced worldwide to combat the Covid-19 pandemic. These vaccines consist of non-amplifying mRNA formulated in lipid nanoparticles (LNPs). Consequently, LNPs are considered benchmark non-viral carriers for nucleic acid delivery. However, the formulation and manufacturing of these mRNA-LNP nanoparticles are expensive and time-consuming. Therefore, we used self-amplifying mRNA (saRNA) and synthesized novel polymers as alternative non-viral carrier platform to LNPs, which enable a simple, rapid, one-pot formulation of saRNA-polyplexes. Our novel polymer-based carrier platform consists of randomly concatenated ethylenimine and propylenimine comonomers, resulting in linear, poly(ethylenimine-ran-propylenimine) (L-PEIx-ran-PPIy) copolymers with controllable degrees of polymerization. Here we demonstrate in multiple cell lines, that our saRNA-polyplexes show comparable to higher in vitro saRNA transfection efficiencies and higher cell viabilities compared to formulations with Lipofectamine MessengerMAX™ (LFMM), a commercial, lipid-based carrier considered to be the in vitro gold standard carrier. This is especially true for our in vitro best performing saRNA-polyplexes with N/P 5, which are characterised with a size below 100 nm, a positive zeta potential, a near 100% encapsulation efficiency, a high retention capacity and the ability to protect the saRNA from degradation mediated by RNase A. Furthermore, an ex vivo hemolysis assay with pig red blood cells demonstrated that the saRNA-polyplexes exhibit negligible hemolytic activity. Finally, a bioluminescence-based in vivo study was performed over a 35-day period, and showed that the polymers result in a higher and prolonged bioluminescent signal compared to naked saRNA and L-PEI based polyplexes. Moreover, the polymers show different expression profiles compared to those of LNPs, with one of our new polymers (L-PPI250) demonstrating a higher sustained expression for at least 35 days after injection.

Distinct adaptation patterns between grip dynamics and arm kinematics when the body is upside-down

In humans, practically all movements are learnt and performed in a constant gravitational field. Yet, studies on arm movements and object manipulation in parabolic flight have highlighted very fast sensorimotor adaptations to altered gravity environments. Here, we wondered if the motor adjustments observed in those altered gravity environments could also be observed on Earth in a situation where the body is upside-down. To address this question, we asked participants to perform rhythmic arm movements in two different body postures (right-side-up and upside-down) while holding an object in precision grip. Analyses of grip-load force coordination and of movement kinematics revealed distinct adaptation patterns between grip and arm control. Grip force and load force were tightly synchronized from the first movements performed in upside-down posture, reflecting a malleable allocentric grip control. In contrast, velocity profiles showed a more progressive adaptation to the upside-down posture and reflected an egocentric planning of arm kinematics. In addition to suggesting distinct mechanisms between grip dynamics and arm kinematics for adaptation to novel contexts, these results also suggest the existence of general mechanisms underlying gravity-dependent motor adaptation that can be used for fast sensorimotor coordination across different postures on Earth and, incidentally, across different gravitational conditions in parabolic flights, in human centrifuges, or in Space.NEW & NOTEWORTHY During rhythmic arm movements performed in an upside-down posture, grip control adapted very quickly, but kinematics adaptation was more progressive. Our results suggest that grip control and movement kinematics planning might operate in different reference frames. Moreover, by comparing our results with previous results from parabolic flight studies, we propose that a common mechanism underlies adaptation to unfamiliar body postures and adaptation to altered gravity.

Corticosteroids and cellulose purification improve, respectively, the in vivo translation and vaccination efficacy of sa-mRNAs

Synthetic mRNAs are an appealing platform with multiple biomedical applications ranging from protein replacement therapy to vaccination. In comparison with conventional mRNA, synthetic self-amplifying mRNAs (sa-mRNAs) are gaining interest because of their higher and longer-lasting expression. However, sa-mRNAs also elicit an innate immune response, which may complicate their clinical application. Approaches to reduce the innate immunity of sa-mRNAs have not been studied in detail. Here we investigated, in vivo, the effect of several innate immune inhibitors and a novel cellulose-based mRNA purification approach on the type I interferon (IFN) response and the translation and vaccination efficacy of our formerly developed sa-mRNA vaccine against Zika virus. Among the investigated inhibitors, we found that corticosteroids and especially topical application of clobetasol at the sa-mRNA injection site was the most efficient in suppressing the type I IFN response and increasing the translation of sa-mRNA. However, clobetasol prevented formation of antibodies against sa-mRNA-encoded antigens and should therefore be avoided in a vaccination context. Residual dsRNA by-products of the in vitro transcription reaction are known inducers of immediate type I IFN responses. We additionally demonstrate a drastic reduction of these dsRNA by-products upon cellulose-based purification, reducing the innate immune response and improving sa-mRNA vaccination efficacy.

Acamprosate and diazepam differentially modulate alcohol-induced behavioural and cortical alterations in rats following chronic inhalation of ethanol vapour

The effects of Acamprosate (the calcium salt of an acetylated form of homotaurine) and the benzodiazepine-receptor agonist Diazepam, were investigated on the alcohol-induced behavioural preference towards alcohol following chronic alcoholization by inhalation. We also examined the effects of Acamprosate and Diazepam on the blood alcohol level (BAL) and on the cortical microvascular network. Acamprosate (50, 100, 200 and 400 mg/kg daily per os during the alcoholization period) did not significantly reduce either BAL or alcohol-induced cortical hypervascularization. Increasing dosages of Acamprosate (i.e. 50, 100, and 200 mg/kg/day), however, progressively reduced preference for alcohol as expressed in a free choice beverage procedure, whereas 400 mg/kg/day of Acamprosate immediately stopped this behaviour. Acamprosate (50 mg/kg/day) also reduced the spontaneous activity of rats during the withdrawal syndrome. By contrast, Diazepam (5 mg/kg) induced inversion in the animals' choice (i.e. increased water consumption versus decreased alcohol intake) during the same experimental procedure, and potentiated the alcohol-induced hypermotility of the animals during the withdrawal syndrome without altering cortical hypervascularization. Taken together, our data provide evidence that both substances exert dose-dependent effects on preference towards alcohol, but display opposite profiles on spontaneous motor activity during the withdrawal phase without any modification of brain microvascularization or blood alcohol levels.

Naftidrofuryl in the treatment of subacute stroke

In a placebo-controlled, double-blind study, 82 patients in the subacute stage of a disabling stroke were studied to assess the effect on clinical improvement of 600 mg naftidrofuryl against placebo. Forty-two patients were treated with the drug and 40 with placebo, in each case administered for 60 days. All patients received 100 mg aspirin and 300 mg dipyridamole daily and entered a similar program of rehabilitation therapy. At the start and the end of the study, the motor functions of the upper and lower limbs, the ability to walk and to perform daily activities, the comprehension and expression of speech, and the mental progress were assessed with quantitative linear scales. In the group treated with active drug, a greater overall tendency of improvement was observed, reaching statistically significant levels for walking and activities of daily life when compared to placebo-treated patients. Overall improvement was negatively influenced by advancing age, but the statistically significant effect of treatment on walking and daily activities was not interfered with by age. Right-sided lesions showed better improvement under active drug than left-sided lesions. This may be due to a correctional effect of naftidrofuryl on hemispatial neglect.

In vitro fertilization and embryo transfer as related to endogenous luteinizing hormone rise or human chorionic gonadotropin administration

After ovarian stimulation with clomiphene citrate combined with human menopausal gonadotropin for in vitro fertilization, the appearance of a spontaneous luteinizing hormone (LH) surge before fulfillment of the minimal criteria of follicular maturity (at least one follicle greater than 19 mm and serum estradiol [E2] greater than 400 pg/ml/follicle greater than 17 mm) is associated with reduced pregnancy rates. In these cases, follicles are smaller and serum E2 values are lower at the time of the LH surge. Oocyte recovery rate is reduced, embryonic anucleate fragments are more frequently observed, and the level of luteal progesterone on day 4 after oocyte retrieval is lower. Hyperandrogenic patients are more prone to display such premature spontaneous LH surge. We concluded that in case of an untimely LH rise, laparoscopy for oocyte retrieval should be cancelled.