To develop an inhalable drug delivery system, we synthesized poly (lactic-co-glycolic acid) nanoparticles with Remdesivir (RDV NPs) as an antiviral agent against SARS-CoV-2 replication and formulated Remdesivir-loaded nanocomposites (RDV NCs) via coating of RDV NPs with novel supramolecular cell-penetrating peptide nanofibers (NFs) to enhance cellular uptake and intracellular drug delivery. RDV NPs and RDV NCs were characterized using variou techniques, including Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and fluorescent microscopy. The cytotoxicity of RDV NCs was assessed in Vero E6 cells and primary human lung epithelial cells, with no significant cytotoxicity observed up to 1000 μg mL⁻¹ and 48 h. RDV NCs were spherically shaped with a size range of 200–300 nm and a zeta potential of ∼+31 mV as well as indicating the presence of coated nanofibers. Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR), immunofluorescence and plaque assays of SARS-CoV-2 infected Vero E6 treated with RDV NCs showed significantly higher antiviral activities compared to those of free drug and uncoated RDV NPs. RDV NCs exhibited high antiviral activity against SARS-CoV-2, and the nanocomposite platform has the potential to be developed into an inhalable drug delivery system for other viral infections in the lungs.

Zika virus (ZIKV) is a mosquito-transmitted flavivirus that has caused devastating congenital Zika syndrome (CZS), including microcephaly, congenital malformation, and fetal demise in human newborns in recent epidemics. ZIKV infection can also cause Guillain-Barré syndrome (GBS) and meningoencephalitis in adults. Despite intensive research in recent years, there are no approved vaccines or antiviral therapeutics against CZS and adult Zika diseases. In this report, we developed a novel live-attenuated ZIKV strain (named Z7) by inserting 50 RNA nucleotides (nt) into the 5′ untranslated region (UTR) of a pre-epidemic ZIKV Cambodian strain, FSS13025. We used this particular ZIKV strain as it is attenuated in neurovirulence, immune antagonism, and mosquito infectivity compared with the American epidemic isolates. Our data demonstrate that Z7 replicates efficiently and produces high titers without causing apparent cytopathic effects (CPE) in Vero cells or losing the insert sequence, even after ten passages. Significantly, Z7 induces robust humoral and cellular immune responses that completely prevent viremia after a challenge with a high dose of an American epidemic ZIKV strain PRVABC59 infection in type I interferon (IFN) receptor A deficient (Ifnar1^−/−) mice. Moreover, adoptive transfer of plasma collected from Z7 immunized mice protects Ifnar1^−/− mice from ZIKV (strain PRVABC59) infection. These results suggest that modifying the ZIKV 5′ UTR is a novel strategy to develop live-attenuated vaccine candidates for ZIKV and potentially for other flaviviruses.

The blastocyst is the preimplantation stage embryo that consists of two major components: the inner cell mass (ICM) and the trophectoderm (TE). The ICM gives rise to the fetus and some extraembryonic tissues whereas the TE contributes to development of the placenta. Previous studies have demonstrated that both human and mouse embryonic stem cells (ESCs) derived from the ICM are deficient in expressing type I IFNs in response to viral infection. In this study, we investigated the IFN response in mouse trophoblast stem cells (TSCs) and their in vitro differentiated trophoblasts (TSC-TBs). In this study, we report that, unlike ESCs, TSCs have a functional IFN system. They can express type I IFNs in response to viral stimuli and express IFN-stimulated genes in response to type I IFNs. TSC-TBs have a further developed IFN system and acquired the ability to express specialized type III IFN-λ. Furthermore, TSCs and TSC-TBs can provide ESCs with antiviral activity against Chikungunya, West Nile, and Zika virus infection, as demonstrated with a novel coculture model that simulates the temporal and spatial relationship between the ICM and the TE in a blastocyst. Taken together, our data demonstrate that mouse ESCs can respond to type I IFNs and gain IFN-based antiviral protection from TSCs and TSC-TBs via paracrine signaling mechanisms even though they themselves are unable to express type I IFNs.

Osteopontin (OPN), a multifunctional protein encoded by the secreted phosphoprotein-1 (Spp-1) gene in humans, plays important roles in a variety of physiological conditions, such as biomineralization, bone remodeling and immune functions. OPN also has significant roles in the pathogenesis of autoimmune, allergy and inflammatory diseases, as well as bacterial, fungal and viral infections. West Nile virus (WNV), a mosquito-transmitted flavivirus, is the leading agent for viral encephalitis in North America. Recent progress has been made in understanding both the biological functions of OPN and the pathogenesis of WNV. In this review article, we have summarized the current understanding of the biology of OPN and its vital roles in the pathogenesis of WNV encephalitis.

Summary: CRISPR-Cas9 (clustered, regularly interspaced, short palindromic repeats with CRISPR-associated protein 9) is a powerful, versatile, and cost-effective molecular tool that can be used for genetic engineering purposes and beyond ¹ and is especially suited for non-model organisms ² . Effective delivery of this system, however, remains a challenge for in vivo genetic manipulation of specific tissues ³ , particularly the brain ⁴ , and in adult indivuduals ^5,6 . We designed a new CRISPR-Cas9 plasmid that was inserted into a baculovirus vector to knockdown the octopamine beta subtype 2 receptor ( AmOctβ2R ), a transmembrane protein found in the mushroom body neurons of the honey bee ( Apis mellifera ) brain, to determine if octopamine plays a role in appetite regulation. We first confirmed that gene editing of AmOctβ2R is possible with Sanger sequencing. We then demonstrated expression of the CRISPR-Cas9 system with the baculovirus vector in vitro using live cell imaging, flow cytometry analysis, and in vivo using confocal imaging, showing widespread expression in the cells and throughout the honey bee brain, three days post treatment. There was also in vitro and in vivo knockdown of AmOctβ2R three days post-infection, that corresponded with appetite suppression in starved forager bees. Our findings suggest that we successfully delivered the CRISPR-Cas9 system and knocked down AmOctB2R in neuronal cells of the honey bee brain that were previously inaccessible due to the blood brain barrier and lack of infectivity of lentivirus vectors ⁷ . The newly characterized AmOctβ2R ⁸ can now be assigned a functional role and other targets for gene editing are now possible using this CRISPR-Cas9 system. Graphical