Dual RNA-Seq characterization of host and pathogen gene expression in liver cells infected with Crimean-Congo Hemorrhagic Fever Virus.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus that can cause a hemorrhagic fever in humans, with a case fatality rate of up to 40%. Cases of CCHFV have been reported in Africa, Asia, and southern Europe; and recently, due to the expanding range of its vector, autochthonous cases have been reported in Spain. Although it was discovered over 70 years ago, our understanding of the pathogenesis of this virus remains limited. We used RNA-Seq in two human liver cell lines (HepG2 and Huh7) infected with CCHFV (strain IbAr10200), to examine kinetic changes in host expression and viral replication simultaneously at 1 and 3 days post infection. Through this, numerous host pathways were identified that were modulated by the virus including: antiviral response and endothelial cell leakage. Notably, the genes encoding DDX60, a cytosolic component of the RIG-I signalling pathway and OAS2 were both shown to be dysregulated. Interestingly, PTPRR was induced in Huh7 cells but not HepG2 cells. This has been associated with the TLR9 signalling cascade, and polymorphisms in TLR9 have been associated with poor outcomes in patients. Additionally, we performed whole-genome sequencing on CCHFV to assess viral diversity over time, and its relationship to the host response. As a result, we have demonstrated that through next-generation mRNA deep-sequencing it is possible to not only examine mRNA gene expression, but also to examine viral quasispecies and typing of the infecting strain. This demonstrates a proof-of-principle that CCHFV specimens can be analyzed to identify both the virus and host biomarkers that may have implications for prognosis.

Downregulation of circulating miR 802-5p and miR 194-5p and upregulation of brain MEF2C along breast cancer brain metastasization.

Breast cancer brain metastases (BCBMs) have been underinvestigated despite their high incidence and poor outcome. MicroRNAs (miRNAs), and particularly circulating miRNAs, regulate multiple cellular functions, and their deregulation has been reported in different types of cancer and metastasis. However, their signature in plasma along brain metastasis development and their relevant targets remain undetermined. Here, we used a mouse model of BCBM and next-generation sequencing (NGS) to establish the alterations in circulating miRNAs during brain metastasis formation and development. We further performed bioinformatics analysis to identify their targets with relevance in the metastatic process. We additionally analyzed human resected brain metastasis samples of breast cancer patients for target expression validation. Breast cancer cells were injected in the carotid artery of mice to preferentially induce metastasis in the brain, and samples were collected at different timepoints (5 h, 3, 7, and 10 days) to follow metastasis development in the brain and in peripheral organs. Metastases were detected from 7 days onwards, mainly in the brain. NGS revealed a deregulation of circulating miRNA profile during BCBM progression, rising from 18% at 3 days to 30% at 10 days following malignant cells' injection. Work was focused on those altered prior to metastasis detection, among which were miR-802-5p and miR-194-5p, whose downregulation was validated by qPCR. Using targetscan and diana tools, the transcription factor myocyte enhancer factor 2C (MEF2C) was identified as a target for both miRNAs, and its expression was increasingly observed in malignant cells along brain metastasis development. Its upregulation was also observed in peritumoral astrocytes pointing to a role of MEF2C in the crosstalk between tumor cells and astrocytes. MEF2C expression was also observed in human BCBM, validating the observation in mouse. Collectively, downregulation of circulating miR-802-5p and miR-194-5p appears as a precocious event in BCBM and MEF2C emerges as a new player in brain metastasis development.

A Novel Triple-Mutant AAV6 Capsid Induces Rapid and Potent Transgene Expression in the Muscle and Respiratory Tract of Mice.

Gene therapy for the treatment of genetic disorders has demonstrated considerable therapeutic success in clinical trials. Among the most effective and commonly used gene delivery vectors are those based on adeno-associated virus (AAV). Despite these advances in clinical gene therapy, further improvements in AAV vector properties such as rapid intracellular processing and transgene expression, targeted transduction of therapeutically relevant cell types, and longevity of transgene expression, will render extension of such successes to many other human diseases. Engineering of AAV capsids continues to evolve the specificity and efficiency of AAV-mediated gene transfer. Here, we describe a triple AAV6 mutant, termed AAV6.2FF, containing F129L, Y445F, and Y731F mutations. AAV6.2FF yielded 10-fold greater transgene expression in lung than AAV6 after 21 days. Additionally, this novel capsid demonstrated 101-fold and 49-fold increased transgene expression in the muscle and lungs, respectively, 24 hr post vector delivery when compared with the parental AAV6. Furthermore, AAV6.2FF retains heparin sulfate binding capacity and displays a 10-fold increase in resistance to pooled immunoglobulin neutralization in vitro. The rapid and potent expression mediated by AAV6.2FF is ideally suited to applications such as vectored immunoprophylaxis, in which rapid transgene expression is vital for use during an outbreak response scenario.