RNA editing of Filamin A pre-mRNA regulates vascular contraction and diastolic blood pressure.

Epitranscriptomic events such as adenosine-to-inosine (A-to-I) RNA editing by ADAR can recode mRNAs to translate novel proteins. Editing of the mRNA that encodes actin crosslinking protein Filamin A (FLNA) mediates a Q-to-R transition in the interactive C-terminal region. While FLNA editing is conserved among vertebrates, its physiological function remains unclear. Here, we show that cardiovascular tissues in humans and mice show massive editing and that FLNA RNA is the most prominent substrate. Patient-derived RNA-Seq data demonstrate a significant drop in FLNA editing associated with cardiovascular diseases. Using mice with only impaired FLNA editing, we observed increased vascular contraction and diastolic hypertension accompanied by increased myosin light chain phosphorylation, arterial remodeling, and left ventricular wall thickening, which eventually causes cardiac remodeling and reduced systolic output. These results demonstrate a causal relationship between RNA editing and the development of cardiovascular disease indicating that a single epitranscriptomic RNA modification can maintain cardiovascular health.

Animal testing for vaccines. Implementing replacement, reduction and refinement: challenges and priorities.

Transition to in vitro alternative methods from in vivo in vaccine release testing and characterization, the implementation of the consistency approach, and a drive towards international harmonization of regulatory requirements are most pressing needs in the field of vaccines. It is critical for global vaccine community to work together to secure effective progress towards animal welfare and to ensure that vaccines of ever higher quality can reach the populations in need in the shortest possible timeframe. Advancements in the field, case studies, and experiences from Low and Middle Income Countries (LMIC) were the topics discussed by an international gathering of experts during a recent conference titled "Animal Testing for Vaccines - Implementing Replacement, Reduction and Refinement: Challenges and Priorities". This conference was organized by the International Alliance for Biological Standardization (IABS), and held in Bangkok, Thailand on December 3 and 4 2019. Participants comprised stakeholders from many parts of the world, including vaccine developers, manufacturers and regulators from Asia, Europe, North America, Australia and New Zealand. In interactive workshops and vibrant panel discussions, the attendees worked together to identify the remaining barriers to validation, acceptance and implementation of alternative methods, and how harmonization could be promoted, especially for LMICs.

Contamination of therapeutic human immunoglobulin preparations with apolipoprotein H (ß2-glycoprotein I).

Polyclonal immunoglobulin (Ig) concentrates are important biological medicinal products and the assurance of their quality and safety is crucial. In our present approach we used proteomic methods to check the purity of commercial Ig products of different origin. The experimental setup included nonreducing 2DE or DIGE combined with MALDI-TOF and the thrombin generation assay, a routine safety test for pharmaceutical Ig preparations, and was complemented by a specific immunoassay. 2DE patterns displayed contaminations with trace amounts of human apolipoprotein H (Apo-H), transferrin, albumin, and its fragments. In contrast to the latter, Apo-H is a protein that is active in the coagulation cascade, and thus a potential involvement in thromboembolic events in vivo cannot be excluded. It was found by 2DE and MALDI-TOF to be a contaminant of several Ig preparations. Spiking experiments of Ig preparations with pure Apo-H demonstrated an Apo-H concentration dependent increase in thrombin generation assay values. Traces of Apo-H are possibly also contributing to unwanted side effects, as already known for factor XIa. The significance of Apo-H contaminations for these side effects might be verified by detailed analyses of pharmacovigilance data.

The Trithorax group protein Ash2l and Saf-A are recruited to the inactive X chromosome at the onset of stable X inactivation.

Mammals compensate X chromosome gene dosage between the sexes by silencing of one of the two female X chromosomes. X inactivation is initiated in the early embryo and requires the non-coding Xist RNA, which encompasses the inactive X chromosome (Xi) and triggers its silencing. In differentiated cells, several factors including the histone variant macroH2A and the scaffold attachment factor SAF-A are recruited to the Xi and maintain its repression. Consequently, in female somatic cells the Xi remains stably silenced independently of Xist. Here, we identify the Trithorax group protein Ash2l as a novel component of the Xi. Ash2l is recruited by Xist concomitantly with Saf-A and macroH2A at the transition to Xi maintenance. Recruitment of these factors characterizes a developmental transition point for the chromatin composition of the Xi. Surprisingly, expression of a mutant Xist RNA that does not cause gene repression can trigger recruitment of Ash2l, Saf-A and macroH2A to the X chromosome, and can cause chromosome-wide histone H4 hypoacetylation. This suggests that a chromatin configuration is established on non-genic chromatin on the Xi by Xist to provide a repressive compartment that could be used for maintaining gene silencing. Gene silencing is mechanistically separable from the formation of this repressive compartment and, thus, requires additional pathways. This observation highlights a crucial role for spatial organization of chromatin changes in the maintenance of X inactivation.

Independent control of COVID-19 vaccines by EU Official Control Authority Batch Release: challenges, strengths and successes.

Vaccines have been a key tool in stemming the tide of the COVID-19 pandemic. The rapid development of effective vaccines against COVID-19, together with their regulatory approval and wide scale distribution has been achieved in an impressively short period thanks to the intense efforts of many. In parallel to vaccine development, the EU considered it important to prepare for the independent control of the COVID-19 vaccines, including testing, to help ensure that only vaccines that comply with the approved quality requirements reach the public and to help improve/increase public confidence in the vaccines. The existing EU Official Control Authority Batch Release (OCABR) system, co-ordinated by the European Directorate for the Quality of Medicines and HealthCare (EDQM), was able to effectively respond to the need, through rapid co-ordination, work-sharing, advance planning and early interaction with manufacturers, the Coalition for Epidemic Preparedness Innovation (CEPI) and regulatory authorities. The Official Medicines Control Laboratories (OMCLs) involved in the OCABR activity, using the strength of the established system in the OCABR network and adaptations to the crisis conditions, were ready to release the first COVID-19 vaccine batches, after protocol review and testing, at the time of the conditional marketing authorisation for each of the COVID-19 vaccines, with no delay for batches reaching the public. Thanks to the dedication of resources by the EU and national authorities as well as by the EDQM, this was done without impacting the release of the other vaccines and human blood and plasma derived medicinal products, essential for public health. Transparency and communication of practices were important factors to support reliance on the OCABR outcome in non-EU countries, with the goal to improve access to vaccines in Europe and beyond. An overview of the process, legal background, challenges and successes of OCABR for COVID-19 vaccines as well as a look at the international perspective and lessons learned is provided.

Proteome diversification by adenosine to inosine RNA editing.

Nucleotide deamination is a widespread phenomenon frequently leading to a change of the genetic information. Adenosine deaminases that act on RNA (ADARs) convert adenosines to inosines in double-stranded or structured regions of RNAs. Inosines are interpreted as guanosines by most cellular processes and hence, this type of modification can affect the coding potential of an RNA but also its splicing, folding or stability, to name a few. While originally believed to be a rare event recent bioinformatic screens have demonstrated that RNA editing by ADARs is widespread and very abundant in mammals. From these screens, editing sites were discovered in both coding and non-coding regions of mRNAs. In this review we focus on RNA editing events that alter the coding potential of mRNAs and hence lead to the formation of proteins that differ from their genomically encoded versions. We will therefore discuss the role of ADARs in proteome diversification, in particular in the nervous system where editing is most abundant.

Microbiological contamination in counterfeit and unapproved drugs.

BACKGROUND: Counterfeit and unapproved medicines are inherently dangerous and can cause patient injury due to ineffectiveness, chemical or biological contamination, or wrong dosage. Growth of the counterfeit medical market in developed countries is mainly attributable to life-style drugs, which are used in the treatment of non-life-threatening and non-painful conditions, such as slimming pills, cosmetic-related pharmaceuticals, and drugs for sexual enhancement. One of the main tasks of health authorities is to identify the exact active pharmaceutical ingredients (APIs) in confiscated drugs, because wrong API compounds, wrong concentrations, and/or the presence of chemical contaminants are the main risks associated with counterfeit medicines. Serious danger may also arise from microbiological contamination. We therefore performed a market surveillance study focused on the microbial burden in counterfeit and unapproved medicines. METHODS: Counterfeit and unapproved medicines confiscated in Canada and Austria and controls from the legal market were examined for microbial contaminations according to the US and European pharmacopoeia guidelines. The microbiological load of illegal and legitimate samples was statistically compared with the Wilcoxon rank-sum test. RESULTS: Microbial cultivable contaminations in counterfeit and unapproved phosphodiesterase type 5 inhibitors were significantly higher than in products from the legal medicines market (p < 0.0001). Contamination levels exceeding the USP and EP limits were seen in 23% of the tested illegal samples in Canada. Additionally, microbiological contaminations above the pharmacopoeial limits were detected in an anabolic steroid and an herbal medicinal product in Austria (6% of illegal products tested). CONCLUSIONS: Our results show that counterfeit and unapproved pharmaceuticals are not manufactured under the same hygienic conditions as legitimate products. The microbiological contamination of illegal medicinal products often exceeds USP and EP limits, representing a potential threat to consumer health.

Xist and the order of silencing.

X inactivation is the mechanism by which mammals adjust the genetic imbalance that arises from the different numbers of gene-rich X-chromosomes between the sexes. The dosage difference between XX females and XY males is functionally equalized by silencing one of the two X chromosomes in females. This dosage-compensation mechanism seems to have arisen concurrently with early mammalian evolution and is based on the long functional Xist RNA, which is unique to placental mammals. It is likely that previously existing mechanisms for other cellular functions have been recruited and adapted for the evolution of X inactivation. Here, we critically review our understanding of dosage compensation in placental mammals and place these findings in the context of other cellular processes that intersect with mammalian dosage compensation.

Selective upregulation of vascular endothelial growth factor receptors neuropilin-1 and -2 in human neuroblastoma.

BACKGROUND: Recent studies show that vascular endothelial growth factor (VEGF) and its receptors Flt-1 and KDR, and a series of other angiogenic molecules, are upregulated in advanced but not low stage human neuroblastoma. Neuropilin-1 and 2 (NRP) are novel specific receptors of VEGF(165), whose role is unknown in human neuroblastoma. METHODS: Tissue biopsies of 37 children with Stage I-IV neuroblastoma were obtained, as well as biopsies of 7 normal adrenals as controls. The mRNA expression of VEGF(165) and its receptors Flt-1, KDR, NRP1, and NRP2 was evaluated by real-time reverse transcription polymerase chain reaction. NRP protein expression was detected by immunocytochemistry and Western blotting. RESULTS: VEGF(165) mRNA was upregulated in Stage III and IV and Flt-1 and KDR gene expression was increased in Stage III, while NRP1 and 2 mRNA and protein levels were higher in Stages I-IV vs. controls (P < 0.05). NRP was expressed in vascular endothelial but not tumor cells. CONCLUSIONS: These results show for the first time that human neuroblastoma expresses NRP, and that NRP co-regulates VEGF angiogenic effect in human neuroblastoma. NRP might be a sensitive angiogenic measure of VEGF systems in neuroblastoma, particularly in its early stages.