Unwinding the SARS-CoV-2 Ribosomal Frameshifting Pseudoknot with LNA and G-Clamp-Modified Phosphorothioate Oligonucleotides Inhibits Viral Replication

Ribosomal frameshifting (RFS) at the slippery site of SARS-CoV-2 RNA is essential for the biosynthesis of the viral replication machinery. It requires the formation of a pseudoknot (PK) structure near the slippery site and can be inhibited by PK-disrupting oligonucleotide-based antivirals. We obtained and compared three types of such antiviral candidates, namely locked nucleic acids (LNA), LNA-DNA gapmers, and G-clamp-containing phosphorothioates (CPSs) complementary to PK stems. Using optical and electrophoretic methods, we showed that stem 2-targeting oligonucleotide analogs induced PK unfolding at nanomolar concentrations, and this effect was particularly pronounced in the case of LNA. For the leading PK-unfolding LNA and CPS oligonucleotide analogs, we also demonstrated dose-dependent RSF inhibition in dual luciferase assays (DLAs). Finally, we showed that the leading oligonucleotide analogs reduced SARS-CoV-2 replication at subtoxic concentrations in the nanomolar range in two human cell lines. Our findings highlight the promise of PK targeting, illustrate the advantages and limitations of various types of DNA modifications and may promote the future development of oligonucleotide-based antivirals.

Multicomponent Lipid Nanoparticles for RNA Transfection

Despite the wide variety of available cationic lipid platforms for the delivery of nucleic acids into cells, the optimization of their composition has not lost its relevance. The purpose of this work was to develop multi-component cationic lipid nanoparticles (LNPs) with or without a hydrophobic core from natural lipids in order to evaluate the efficiency of LNPs with the widely used cationic lipoid DOTAP (1,2-dioleoyloxy-3-[trimethylammonium]-propane) and the previously unstudied oleoylcholine (Ol-Ch), as well as the ability of LNPs containing GM3 gangliosides to transfect cells with mRNA and siRNA. LNPs containing cationic lipids, phospholipids and cholesterol, and surfactants were prepared according to a three-stage procedure. The average size of the resulting LNPs was 176 nm (PDI 0.18). LNPs with DOTAP mesylate were more effective than those with Ol-Ch. Core LNPs demonstrated low transfection activity compared with bilayer LNPs. The type of phospholipid in LNPs was significant for the transfection of MDA-MB-231 and SW 620 cancer cells but not HEK 293T cells. LNPs with GM3 gangliosides were the most efficient for the delivery of mRNA to MDA-MB-231 cells and siRNA to SW620 cells. Thus, we developed a new lipid platform for the efficient delivery of RNA of various sizes to mammalian cells.

Epithelial protective therapy in comorbid diseases. Practical Guidelines for Physicians

In 2021 the first multidisciplinary National Consensus on the pathophysiological and clinical aspects of Increased Epithelial Permeability Syndrome was published. The proposed guidelines are developed on the basis of this Consensus, by the same team of experts. Twenty-eight Practical Guidelines for Physicians statements were adopted by the Expert Council using the "delphic" method. Such main groups of epithelial protective drugs as proton pump inhibitors, bismuth drugs and probiotics are discussed in these Guidelines from the positions of evidence-based medicine. The clinical and pharmacological characteristics of such a universal epithelial protector as rebamipide, acting at the preepithelial, epithelial and subepithelial levels, throughout gastrointestinal tract, are presented in detail.

Emotional, personal, cognitive and other mental disorders after removal of the tumor of the diencephalic region (in the long-term period)

Introduction

In the literature, there are conflicting data regarding the recovery of mental disorders, in particular, pathologies of the emotional, personality, behavioral and cognitive spheres, in patients after surgical treatment of tumors of the diencephalic region.

Objectives

To evaluate the dynamics of psychopathological disorders after removal of a craniopharyngioma.

Methods

45 patients (18–68 y.o.), operated through transcranial access. The follow-up period ranged from 3 months to 9 years (on average 2.8 + 0.4). The main method is psychopathological, supplemented by rating scales and questionnaires.

Results

In the late postoperative period, mental disorders were detected in 75% of patients (Table 1). Table 1. Dynamics of the main psychopathological symptom complexes (n = 45).Disorders (may be a combination)Before surgery (n,%)2 weeks after (n,%)18 months after (n,%)Emotional and volitional27 (60%)27 (60%)15 (33%)Cognitive - Korsakov syndrome18 (40%) 4 (9%)27 (59%) 8 (18%)18 (40%) 7 (15%)Personality21 (46%)25 (55%)23 (51%)

The table shows that emotional-volitional disorders have a clear positive dynamics by 18 months after surgery compared with the preoperative level. Korsakov’s syndrome and personality disorders are less favorable. 23 patients (52%) returned to their previous profession; 22 (48%) stopped working due to a severe degree of disability, of which 7 (15%) need constant supervision.

Conclusions

The positive dynamics of psychopathological symptoms is observed only within 1.5 years after the removal of the craniopharyngioma, in the future they remain without a tendency to improve. 22 patients (48%) stopped working. The most severe degree of disability is 15% patients.

Disclosure

No significant relationships.

OP0132 ALLERGIC ASTHMA INDUCES THE ACCUMULATION OF SYNOVIAL RESIDENT EOSINOPHILS, TRIGGERING THE RESOLUTION OF INFLAMMATORY ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a chronic inflammatory disorder, involving synovial joints, which affects approximately 1 percent of the world population[1]. Our former work demonstrated that the Th2-eosinophil pathway is a strong anti-inflammatory mediator of inflammatory arthritis[2]. Allergic asthma is an inflammatory disease of the airway, triggered by type 2 immune response. Hitherto, clinical observations on the impact of asthma on RA showed controversial results. Herein, we investigated the action of allergic asthma on inflammatory arthritis.

Objectives:

We aimed to delineate the molecular and cellular responses induced by allergic asthma on inflammatory arthritis, particularly depicting the role of eosinophil subsets in arthritic synovium.

Methods:

Allergic asthma was induced in wild type and genetically modified mice by ovalbumin (OVA) treatment. After the initiation of allergic asthma, K/BxN serum was transferred into the asthmatic mice or control mice to trigger serum induced arthritis (SIA). Then, arthritis severity, circulating cytokines and the cytology of lung and synovium were analyzed. Eosinophil subsets were studied by flow cytometry, single cell RNA sequencing analysis, and were isolated and transferred into the synovial cavity of eosinophil deficient arthritic mice. Clinical data of patients with both RA and asthma were collected and checked for the relapse of RA after asthma treatment with anti-interleukin (IL)-5 antibody.

Results:

Mice induced with allergic asthma exhibited a rapid resolution of SIA. The OVA-triggered resolution disappeared in eosinophil deficient mice (ΔdblGATA), and was partially blocked by IL-5 neutralization. We could detect that IL-5 was mainly produced by type 2 innate lymphoid cell (ILC2) in the lung. Allergic asthma exclusively induced the proliferation (Ki67+) and accumulation of synovial resident eosinophils (rEos, Siglec-Fint), which switched classical macrophages into alternatively activated macrophages. Synovial induced eosinophils (iEos, Siglec-Fhigh) appeared only in the acute phase of SIA. Single cell RNA sequencing analysis showed that rEos played an anti-inflammatory role, while iEos had pro-inflammatory properties in arthritis. The roles of rEos and iEos in arthritis were confirmed by transferring rEos/iEos into the synovial cavity of arthritic mice. Patiens with both RA and asthma showed a remission relapse of RA after using humanized monoclonal IL-5 antibody for treating sever eosinophilic asthma.

Conclusion:

Allergic asthma induced an IL-5 mediated proliferation and accumulation of synovial rEos. The latter triggered the resolution of inflammatory arthritis. In human, eosinophils induced by asthma were essential for the sustaining of RA remission.

References:

[1]Myasoedova, E., et al., Is the incidence of rheumatoid arthritis rising?: results from Olmsted County, Minnesota, 1955-2007. Arthritis Rheum, 2010.62(6): p. 1576-82.

[2]Chen, Z., et al., Th2 and eosinophil responses suppress inflammatory arthritis. Nat Commun, 2016.7: p. 11596.

Acknowledgments:

Mengdan Liu and Darja Andreev contributed equally to this study

Disclosure of Interests:

Mengdan Liu: None declared, Darja Andreev: None declared, Katerina Kachler: None declared, Julia Koelle: None declared, Simon Rauber: None declared, Andreas Ramming Grant/research support from: Pfizer, Novartis, Consultant of: Boehringer Ingelheim, Novartis, Gilead, Pfizer, Speakers bureau: Boehringer Ingelheim, Roche, Janssen, Susetta Finotto: None declared, Georg Schett Speakers bureau: AbbVie, BMS, Celgene, Janssen, Eli Lilly, Novartis, Roche and UCB, Aline Bozec: None declared

Localization and distribution of laminin in the basal lamina of certain mechanoreceptors—an immunogold study

The applied immunogold cytochemical technique in investigating the cytologic distribution of the laminin (LAM) molecule in the capsulated Pacinian and Herbst mechanoreceptors shows the presence of LAM around most elements of the receptor structures. The LAM immunoreactivity (LAM-IR) is best expressed in the vicinity of the perineural capsule cells of both receptor types, where it is primarily concentrated around the perinuclear regions as well as the cytoplasmic lamellae. Such a localization overlaps with the already known ultrastructural localization of a basal lamina (BL) around these cells. Laminin immunoreactivity is less well expressed around the modified Schwann cells. Even in these cells, however, there is an apparent immunoreaction around the cytoplasmic lamellae regardless of the lamellar location. In both receptor types, there is no LAM-IR in the cells of the subcapsular space. Of particular significance we consider the localization of gold particles (respectively the presence of a BL) between the innermost lamellae of the modified Schwann cells and the non-myelinated part of the receptor nerve fiber and their endings, as well as around the axoplasmic protrusions of the nerve endings. We discuss the role of the BL and LAM in the investigated rapidly adapting mechanoreceptors and their trophic influence upon the sensory regions. We also assume the arresting and selective effect of these membranes in building up the ion channels of the axolemma which probably has a certain importance in mechanotransduction.

Multiple origins of cyclodiene insecticide resistance in Tribolium castaneum (Coleoptera: Tenebrionidae)

The number of origins of pesticide resistance-associated mutations is important not only to our understanding of the evolution of resistance but also in modeling its spread. Previous studies of amplified esterase genes in a highly dispersive Culex mosquito have suggested that insecticide resistance-associated mutations (specifically a single-gene duplication event) can occur a single time and then spread throughout global populations. In order to provide data for resistance-associated point mutations, which are more typical of pesticide mechanisms as a whole, we studied the number of independent origins of cyclodiene insecticide resistance in the red flour beetle Tribolium castaneum. Target-site insensitivity to cyclodienes is conferred by single point mutations in the gene Resistance to dieldrin (Rdl), which codes for a subunit of a gamma-aminobutyric acid (GABA) receptor. These point mutations are associated with replacements of alanine 302 which render the receptor insensitive to block by the insecticide. We collected 141 strains of Tribolium worldwide and screened them for resistance. Twenty-four strains contained resistant individuals. After homozygosing 23 of these resistance alleles we derived a nucleotide sequence phylogeny of the resistant strains from a 694-bp section of Rdl, encompassing exon 7 (which contains the resistance-associated mutation) and part of a flanking intron. The phylogeny also included six susceptible alleles chosen at random from a range of geographical locations. Resistance alleles fell into six clades and three clades contained both resistant and susceptible alleles. Although statistical analysis provided support at only the 5-6% level, the pattern of variation in resistance alleles is more readily explained by multiple independent origins of resistance than by spread of a single resistance-associated mutation. For example, two resistance alleles differed from two susceptible alleles only by the resistance-associated mutation itself, suggesting that they form the susceptible ancestors and that resistance arose independently in several susceptible backgrounds. This suggests that in Tribolium Rdl, de novo mutations for resistance have arisen independently in several populations. Identical alleles were found in geographically distant regions as well, also implying that some Rdl alleles have been exported in stored grain. These differences from the Culex study may stem both from differences in the population genetics of Tribolium versus that of mosquitoes and differences in mutation rates associated with point mutations versus gene duplication events. The Tribolium data therefore suggest that multiple origins of insecticide resistance (associated with specific point mutations) may be more common than the spread of single events. These findings have implications for the way in which we model the evolution and spread of insecticide resistance genes and also suggest that parallel adaptive substitutions may not be uncommon in phyletic evolution.

Lack of nucleotide variability in a beetle pest with extreme inbreeding

The coffee berry borer beetle Hypothenemus hampei (Ferrari) (Curculionidae: Scolytinae) is the major insect pest of coffee and has spread to most of the coffee-growing countries of the world. This beetle also displays an unusual life cycle, with regular sibling mating. This regular inbreeding and the population bottlenecks occurring on colonization of new regions should lead to low levels of genetic diversity. We were therefore interested in determining the level of nucleotide variation in nuclear and mitochondrial genomes of this beetle worldwide. Here we show that two nuclear loci (Resistance to dieldrin and ITS2) are completely invariant, whereas some variability is maintained at a mitochondrial locus (COI), probably corresponding to a higher mutation rate in the mitochondrial genome. Phylogenetic analysis of the mitochondrial data shows only two clades of beetle haplotypes outside of Kenya, the proposed origin of the species. These data confirm that inbreeding greatly reduces nucleotide variation and suggest the recent global spread of only two inbreeding lines of this bark beetle.

Tubular networks in soleus muscle fibers of the rat following tenotomy. I. Spatial organization

Complex systems of tubules, 30-40 nm in diameter, were observed in myofibers of the soleus muscle of Wistar rats following experimental transection of the Achilles tendon. The appearance of these systems varied remarkably, depending upon the plane of sectioning. The spacial arrangement of the tubules was reconstructed by comparing several sections through individual systems. Such reconstructions revealed that they are networks of tubular elements arranged in an hexagonal pattern. A three-dimensional wire model was prepared, illustrating the spatial organization of the tubular systems. The model consists of four groups of lattices with a honeycomb-like arrangement. The lattices of each group are parallel to one another, and intersect those of the other groups at an inclination of 60 degrees.