Hepatitis C virus (HCV) is a positive-strand RNA virus replicating in a membranous replication organelle composed primarily of double-membrane vesicles (DMVs) having morphological resemblance to autophagosomes. To define the mechanism of DMV formation and the possible link to autophagy, we conducted a yeast two-hybrid screening revealing 32 cellular proteins potentially interacting with HCV proteins. Among these was the Receptor for Activated Protein C Kinase 1 (RACK1), a scaffolding protein involved in many cellular processes, including autophagy. Depletion of RACK1 strongly inhibits HCV RNA replication without affecting HCV internal ribosome entry site (IRES) activity. RACK1 is required for the rewiring of subcellular membranous structures and for the induction of autophagy. RACK1 binds to HCV nonstructural protein 5A (NS5A), which induces DMV formation. NS5A interacts with ATG14L in a RACK1 dependent manner, and with the ATG14L-Beclin1-Vps34-Vps15 complex that is required for autophagosome formation. Both RACK1 and ATG14L are required for HCV DMV formation and viral RNA replication. These results indicate that NS5A participates in the formation of the HCV replication organelle through interactions with RACK1 and ATG14L. All positive-strand RNA viruses replicate their genomes in distinct membrane-associated compartments designated replication organelles. The compartmentalization of viral replication machinery allows the enrichment and coordination of cellular and viral factors required for RNA replication and the evasion from innate host defense systems. Hepatitis C virus (HCV), a prototype member of the Flaviviridae family, rearranges intracellular membranes to construct replication organelles composed primarily of double-membrane vesicles (DMVs) which are morphologically similar to autophagosomes. Nonstructural protein 5A (NS5A), which is essential for HCV replication, induces DMV formation. Here, we report that NS5A triggers DMV formation through interactions with RACK1 and components of the vesicle nucleation complex acting at the early stage of autophagy. These results illustrate how a virus skews cellular machineries to utilize them for its replication by hijacking cellular proteins through protein-protein interactions. This research sheds light on the molecular basis of replication organelle formation by HCV and possibly other viruses employing organelles with DMV morphology.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused devastation to human society through its high virulence, infectivity, and genomic mutations, which reduced the efficacy of vaccines. Here, we report the development of aptamers that effectively interfere with SARS-CoV-2 infection by targeting its spike protein, which plays a pivotal role in host cell entry of the virus through interaction with the viral receptor angiotensin-converting enzyme 2 (ACE2). To develop highly effective aptamers and to understand their mechanism in inhibiting viral infection, we determined the three-dimensional (3D) structures of aptamer/receptor-binding domain (RBD) complexes using cryogenic electron microscopy (cryo-EM). Moreover, we developed bivalent aptamers targeting two distinct regions of the RBD in the spike protein that directly interact with ACE2. One aptamer interferes with the binding of ACE2 by blocking the ACE2-binding site in RBD, and the other aptamer allosterically inhibits ACE2 by binding to a distinct face of RBD. Using the 3D structures of aptamer–RBD complexes, we minimized and optimized these aptamers. By combining the optimized aptamers, we developed a bivalent aptamer that showed a stronger inhibitory effect on virus infection than the component aptamers. This study confirms that the structure-based aptamer-design approach has a high potential in developing antiviral drugs against SARS-CoV-2 and other viruses.

The emergence of numerous SARS-CoV-2 variants, characterized by mutations in the viral RNA genome and target proteins, has presented challenges for accurate COVID-19 diagnosis. To address this, we developed universal aptamer probes capable of binding to the spike proteins of SARS-CoV-2 variants, including highly mutated strains like Omicron. These aptamers were identified through protein-based SELEX using spike proteins from three key variants (D614G-substituted Wuhan-Hu-1, Delta, and Omicron) and virus-based SELEX, known as viro-SELEX. Leveraging these universal aptamers, we created a highly sensitive lateral flow assay (LFA) and an ultra-sensitive molecular diagnostic platform that integrates a novel rapid PCR technique, enabling fast and reliable detection across all SARS-CoV-2 variants.

Cyanobacterial harmful algal blooms are increasingly recognized as a global environmental challenge, largely driven by nutrient enrichment and eutrophication of freshwater systems. Among the toxins produced during these blooms, microcystins—particularly microcystin-LR—have attracted considerable scientific attention due to their persistence in aquatic environments and their potential impacts on ecosystems, agriculture, and public health. This systematic review and meta-analysis synthesize evidence from 35 experimental and observational studies to evaluate the ecological and human health consequences of microcystin exposure across plant systems, microbial communities, and human populations. A comprehensive literature search was conducted across major scientific databases following PRISMA guidelines, and quantitative data were analyzed using random-effects meta-analysis models. The results reveal consistent inhibitory effects of microcystins on plant growth and physiology, including reductions in biomass, root development, and photosynthetic performance. Leafy vegetables such as lettuce and spinach appear particularly sensitive, while cereal crops including rice and wheat also show measurable physiological stress under toxin exposure. Beyond plant toxicity, microcystins significantly alter microbial community structure, reducing diversity and disrupting nutrient-cycling functions essential for ecosystem stability. Evidence of human exposure was also identified, with detectable microcystin concentrations reported in serum samples from populations exposed to contaminated water sources. Dose–response analyses further demonstrate that ecological and physiological effects intensify with increasing toxin concentrations. Overall, this synthesis highlights the interconnected ecological and public health risks associated with microcystin contamination. The findings underscore the importance of integrated monitoring, improved water management practices, and interdisciplinary research to mitigate the impacts of cyanobacterial toxins in agricultural landscapes and food production systems.