Synergistic correlation between host angiogenin and dengue virus replication

Exploiting Host Kinases to Combat Dengue Virus Infection and Disease

The burden of dengue on human health has dramatically increased in recent years, underscoring the urgent need for effective therapeutic interventions. Despite decades of research since the discovery of the dengue virus, no specific antiviral treatments are available and strategies to reliably prevent severe disease remain limited. Direct-acting antivirals against dengue are under active investigation but have shown limited efficacy to date. An underappreciated Achille's heal of the virus is its dependence on host factors for infection and pathogenesis, each of which presents a potential avenue for therapeutic intervention. We and others have demonstrated that dengue virus relies on multiple host kinases, some of which are already targeted by clinically approved inhibitors. These offer drug repurposing opportunities for host-directed dengue treatment. Here, we summarize findings on the role of kinases in dengue infection and disease and highlight potential kinase targets for the development of innovative host-directed therapeutics.

Advances in Nanobiosensors for Rapid and Sensitive Detection of Dengue Virus Biomarkers by Using Clinical Laboratory

BACKGROUND

The recent rise in dengue virus (DENV) cases poses a significant threat to human health, with infections ranging from mild to severe and potentially leading to premature death.

OBJECTIVE

To highlight the importance of early detection of DENV and to review advancements in detection technologies, particularly focusing on nanobiosensors.

METHODS

This review examines traditional detection methods for DENV, including molecular, serological, and direct virus culture techniques, while discussing their limitations. It also explores innovative technologies that enhance detection accuracy, speed, and efficiency.

RESULTS

Nonstructural protein 1 (NS1) serves as a key biomarker present in high concentrations during the early stages of DENV infection, underscoring the need for timely detection. Traditional methods, while effective, have limitations that new technologies aim to address. Biosensors, particularly nanobiosensors, have emerged as promising tools for rapid, sensitive, and cost-effective DENV detection.

CONCLUSION

The adoption of advanced detection methods, especially nanobiosensors, is crucial for improving DENV management and reducing human suffering. This review provides a comprehensive overview of nanobiosensors and their applications, presented in an accessible manner for readers.

Dengue Virus Life Cycle and Host Protein Interactions: Focus on RNA Binding Proteins and Therapeutic Advances

Dengue, a widespread arthropod-borne viral disease, remains endemic in more than 100 nations, affecting over 40% of the world's population, with millions of cases reported annually, and has a major burden on global public health systems. The causative agent of this infection is the dengue virus which belongs to the Flaviviridae family of RNA viruses. The DENV infection leads to a broad spectrum of clinical symptoms, ranging from mild to severe, and even fatal in the cases of secondary infection. In the absence of promising antiviral therapies or vaccines to effectively combat the infection, understanding the interaction between the host and pathogen, along with the associated molecular mechanisms, is crucial. In this review, we focused on the specialised functions of various RNA-binding proteins (RBPs) and their roles at various stages of the viral life cycle. This review examines the intricate interplay between viral and host cellular factors. Notably, numerous host RBPs, including La, eIF2, PTBP1, YBX1, and other hnRNPs, interact with viral components, such as NS2A, NS2B, NS3, NS4A, NS4B and NS5, and most importantly, the viral UTRs (untranslated regions), to facilitate critical stages of the viral life cycle. We comprehensively compiled the specific roles of RBPs in the dengue virus life cycle, including viral entry, translation, transcription, and assembly, and further explored the therapeutic possibilities.

Biotin-Based Northern Blotting (BiNoB): A Cost-Efficient Alternative for Detection of Small RNAs

Advances in sequencing technology have led to the discovery of diverse types of regulatory RNAs. Differential transcript levels regulate cellular processes and influence disease severity. Identifying these variations through reliable methods is crucial for understanding the regulatory roles and disease mechanisms of regulatory RNAs. Northern blotting, which is considered the gold standard for differential expression analysis, poses challenges due to various limitations associated with RNA quality and integrity, radioactivity exposure, and associated reagents and expenses. In this protocol, we employ a biotin-based northern blotting (BiNoB) approach that is both convenient and inexpensive, eliminating the need for specialized settings as required with radioactivity-based northern blotting. We comprehensively target various RNA types, making this technique a versatile tool for RNA detection. Additionally, we conduct a comparison between 3'-end labeled probes that were labeled in-house and 5'-end labeled probes that were obtained commercially. Remarkably, our results reveal relatively higher sensitivity with 3'-end labeled probes. Furthermore, we demonstrated that the use of an in-house buffer offered comparable sensitivity to a commercially available buffer, providing another cost-effective alternative. We also aimed to determine the minimum quantity of total RNA required to detect small non-coding RNAs such as tRNA fragments. Whereas previous studies reported the use of 5-10 µg total RNA for tRNA fragment detection, our findings revealed that as little as 1 µg total RNA is sufficient to detect small RNAs like tRNAs and their fragments. This concentration may vary depending on the expression levels of the specific RNAs being detected. © 2024 Wiley Periodicals LLC. Basic Protocol: Biotin-based northern blotting.

Viral hijacking of hnRNPH1 unveils a G-quadruplex-driven mechanism of stress control

Viral genomes are enriched with G-quadruplexes (G4s), non-canonical structures formed in DNA or RNA upon assembly of four guanine stretches into stacked quartets. Because of their critical roles, G4s are potential antiviral targets, yet their function remains largely unknown. Here, we characterize the formation and functions of a conserved G4 within the polymerase coding region of orthoflaviviruses of the Flaviviridae family. Using yellow fever virus, we determine that this G4 promotes viral replication and suppresses host stress responses via interactions with hnRNPH1, a host nuclear protein involved in RNA processing. G4 binding to hnRNPH1 causes its cytoplasmic retention with subsequent impacts on G4-containing tRNA fragments (tiRNAs) involved in stress-mediated reductions in translation. As a result, these host stress responses and associated antiviral effects are impaired. These data reveal that the interplay between hnRNPH1 and both host and viral G4 targets controls the integrated stress response and viral replication.

Unravelling tRNA fragments in DENV pathogenesis: Insights from RNA sequencing

Small non-coding RNAs (sncRNAs) derived from tRNAs are known as tRNA-derived small RNAs (tsRNAs). These tsRNAs are further categorized into tRNA-derived fragments (tRFs) and tRNA halves (tiRNAs), which play significant roles in the various molecular mechanisms underlying certain human diseases. However, the generation of tsRNAs and their potential roles during Dengue virus (DENV) infection is not yet known. Here, we performed small RNA sequencing to identify the generation and alterations in tsRNAs expression profiles of DENV-infected Huh7 cells. Upon DENV infection, tRNA fragmentation was found to be increased. We identified a significant number of differentially expressed tsRNAs during DENV infection. Interestingly, the 3'tRF population showed upregulation, while the i-tRF population exhibited downregulation. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed to analyze the impact of differentially expressed tsRNAs on DENV pathogenesis. Our results suggest that differentially expressed tsRNAs are involved in transcriptional regulation via RNA polymerase II promoter and metabolic pathways. Overall, our study contributes significantly to our understanding of the roles played by tsRNAs in the complex dynamics of DENV infection.

Effects of Pathogenic Mutants of the Neuroprotective RNase 5-Angiogenin in Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that affects the motoneurons. More than 40 genes are related with ALS, and amyloidogenic proteins like SOD1 and/or TDP-43 mutants are directly involved in the onset of ALS through the formation of polymorphic fibrillogenic aggregates. However, efficacious therapeutic approaches are still lacking. Notably, heterozygous missense mutations affecting the gene coding for RNase 5, an enzyme also called angiogenin (ANG), were found to favor ALS onset. This is also true for the less-studied but angiogenic RNase 4. This review reports the substrate targets and illustrates the neuroprotective role of native ANG in the neo-vascularization of motoneurons. Then, it discusses the molecular determinants of many pathogenic ANG mutants, which almost always cause loss of function related to ALS, resulting in failures in angiogenesis and motoneuron protection. In addition, ANG mutations are sometimes combined with variants of other factors, thereby potentiating ALS effects. However, the activity of the native ANG enzyme should be finely balanced, and not excessive, to avoid possible harmful effects. Considering the interplay of these angiogenic RNases in many cellular processes, this review aims to stimulate further investigations to better elucidate the consequences of mutations in ANG and/or RNase 4 genes, in order to achieve early diagnosis and, possibly, successful therapies against ALS.

Dengue virus pathogenesis and host molecular machineries

Dengue viruses (DENV) are positive-stranded RNA viruses belonging to the Flaviviridae family. DENV is the causative agent of dengue, the most rapidly spreading viral disease transmitted by mosquitoes. Each year, millions of people contract the virus through bites from infected female mosquitoes of the Aedes species. In the majority of individuals, the infection is asymptomatic, and the immune system successfully manages to control virus replication within a few days. Symptomatic individuals may present with a mild fever (Dengue fever or DF) that may or may not progress to a more critical disease termed Dengue hemorrhagic fever (DHF) or the fatal Dengue shock syndrome (DSS). In the absence of a universally accepted prophylactic vaccine or therapeutic drug, treatment is mostly restricted to supportive measures. Similar to many other viruses that induce acute illness, DENV has developed several ways to modulate host metabolism to create an environment conducive to genome replication and the dissemination of viral progeny. To search for new therapeutic options, understanding the underlying host-virus regulatory system involved in various biological processes of the viral life cycle is essential. This review aims to summarize the complex interaction between DENV and the host cellular machinery, comprising regulatory mechanisms at various molecular levels such as epigenetic modulation of the host genome, transcription of host genes, translation of viral and host mRNAs, post-transcriptional regulation of the host transcriptome, post-translational regulation of viral proteins, and pathways involved in protein degradation.