A family of glycoconjugates has recently been shown to share a common carbohydrate epitope recognized by the mouse monoclonal antibody HNK-1. The specificity of HNK-1 was found to be similar to that of another monoclonal antibody, NC-1. These two IgM monoclonal antibodies were raised after immunization of mice with a human T-cell line and avian neural crest-derived ganglia, respectively. The antigens recognized by these antibodies include the myelin-associated glycoprotein, MAG, a glycolipid of defined structure, and a set of molecules involved in cell adhesion. The timing and pattern of appearance of these antigens are distinct. Moreover, the epitope may be absent on an antigen at a given stage or in a given tissue. Therefore, although the molecules able to carry the NC-1/HNK-1 epitope are numerous and expressed in various tissues, the use of the monoclonal antibodies on tissue sections has proven adequate for following the migration of avian neural crest cells, the major cell lineage recognized by NC-1 and HNK-1 during early embryogenesis. Analogies in several other species have been found on the basis of HNK-1 reactivity. In this study we show that NC-1 and HNK-1 can be used successfully to label migrating neural crest cells in dog, pig and human. On the other hand, the NC-1/HNK-1 epitope was not present on migrating crest cells in amphibians or mice and was found only transiently on the neural crest of rats.

RNA interference (RNAi) is a post-transcriptional gene silencing mechanism that mediates the sequence-specific degradation of targeted RNA and thus provides a tremendous opportunity for development of oligonucleotide-based drugs. Here, we report on the design and validation of small interfering RNAs (siRNAs) targeting highly conserved regions of the hepatitis C virus (HCV) genome. To aim for therapeutic applications by optimizing the RNAi efficacy and reducing potential side effects, we considered different factors such as target RNA variations, thermodynamics and accessibility of the siRNA and target RNA, and off-target effects. This aim was achieved using an in silico design and selection protocol complemented by an automated MysiRNA-Designer pipeline. The protocol included the design and filtration of siRNAs targeting highly conserved and accessible regions within the HCV internal ribosome entry site, and adjacent core sequences of the viral genome with high-ranking efficacy scores. Off-target analysis excluded siRNAs with potential binding to human mRNAs. Under this strict selection process, two siRNAs (HCV353 and HCV258) were selected based on their predicted high specificity and potency. These siRNAs were tested for antiviral efficacy in HCV genotype 1 and 2 replicon cell lines. Both in silico-designed siRNAs efficiently inhibited HCV RNA replication, even at low concentrations and for short exposure times (24h); they also exceeded the antiviral potencies of reference siRNAs targeting HCV. Furthermore, HCV353 and HCV258 siRNAs also inhibited replication of patient-derived HCV genotype 4 isolates in infected Huh-7 cells. Prolonged treatment of HCV replicon cells with HCV353 did not result in the appearance of escape mutant viruses. Taken together, these results reveal the accuracy and strength of our integrated siRNA design and selection protocols. These protocols could be used to design highly potent and specific RNAi-based therapeutic oligonucleotide interventions.

IntroductionHepatitis C virus (HCV) infection persists in most infected individuals and can lead to the development of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) have a crucial role in various liver diseases, especially HCC. The expression profiles of circulating microRNAs have been studied aiming at the identification of novel non-invasive biomarkers. This study aims to develop a non-invasive diagnostic tool based on measuring the serum levels of different miRNAs in order to detect HCV-induced HCC at the early stages of the disease.Material and methodsFive main miRNAs (miRNA-122a, miRNA-125a, miRNA-139, miRNA-145, and miRNA-199a) were selected according to the literature that demonstrated their unique expression pattern during HCC development. Serum samples were collected from 42 cases of chronic hepatitis C (CHC) without cirrhosis, 45 cases of CHC with cirrhosis (LC), 38 cases of HCC with HCV, and 40 healthy individuals serving as a control. The five miRNAs were measured using real-time reverse transcription PCR. The conventional HCC markers α-fetoprotein (AFP) and des-γ-carboxyprothrombin (DCP) were measured with commercial kits.ResultsSerum levels of miRNA-122a, miRNA-125a, miRNA-139, miRNA-145, and miRNA-199a were significantly lower (p < 0.01) in HCC than in CHC and LC groups. As a single marker, miRNA-122a had the highest sensitivity for HCC, followed by miRNA-199a, miRNA-145, miRNA-139, and miRNA-125a.ConclusionsThese findings indicate that measurement of serum levels of miRNA-122a, miRNA-125a, miRNA-139, miRNA-145, and miRNA-199a can differentiate HCC from CHC and LC. Our results suggest that serum miR-122 might serve as a novel and potential noninvasive biomarker for HCV-induced HCC.

One of the main protective measures against COVID-19's spread is the use of face masks. It is therefore of the utmost importance for face masks to be high functioning in terms of their filtration ability and comfort. Notwithstanding the prevalence of the commercial polypropylene face masks, its effectiveness is under contention, leaving vast room for improvement. During the pandemic, the use of at least one mask per day for each individual results in a massive number of masks that need to be safely disposed of. Fabricating biodegradable filters of high efficiency not only can protect individuals and save the environment but also can be sewed on reusable/washable cloth masks to reduce expenses. Wearing surgical masks for long periods of time, especially in hot regions, causes discomfort by irritating sensitive facial skin and warmed inhaled air. Herein, we demonstrate the fabrication of novel electrospun composites layers as face mask filters for protection against pathogens and tiny particulates. The combinatorial filter layers are made by integrating TiO 2 nanotubes as fillers into chitosan/poly(vinyl alcohol) polymeric electrospun nanofibers as the outer layer. The other two fillerfree layers, chitosan/poly(vinyl alcohol) and silk/poly(vinyl alcohol) as the middle and inner composite layers, respectively, were used for controlled protection, contamination prevention, and comfort for prolonged usage. The ASTM standards evaluation tests were adopted to evaluate the efficacy of the assembled filter, revealing high filtration efficiency compared to that of commercial surgical masks. The TiO 2 /Cs/PVA outer layer significantly reduced Staphylococcus aureus bacteria by 44.8% compared to the control, revealing the dual effect of TiO 2 and chitosan toward the infectious bacterial colonies. Additionally, molecular dynamics calculations were used to assess the mechanical properties of the filter layers.