Targeting Herpes Simplex Virus-1 gD by a DNA Aptamer Can Be an Effective New Strategy to Curb Viral Infection.

Herpes simplex virus type 1 (HSV-1) is an important factor for vision loss in developed countries. A challenging aspect of the ocular infection by HSV-1 is that common treatments, such as acyclovir, fail to provide effective topical remedies. Furthermore, it is not very clear whether the viral glycoproteins, required for HSV-1 entry into the host, can be targeted for an effective therapy against ocular herpes in vivo. Here, we demonstrate that HSV-1 envelope glycoprotein gD, which is essential for viral entry and spread, can be specifically targeted by topical applications of a small DNA aptamer to effectively control ocular infection by the virus. Our 45-nt-long DNA aptamer showed high affinity for HSV-1 gD (binding affinity constant [Kd] = 50 nM), which is strong enough to disrupt the binding of gD to its cognate host receptors. Our studies showed significant restriction of viral entry and replication in both in vitro and ex vivo studies. In vivo experiments in mice also resulted in loss of ocular infection under prophylactic treatment and statistically significant lower infection under therapeutic modality compared to random DNA controls. Thus, our studies validate the possibility that targeting HSV-1 entry glycoproteins, such as gD, can locally reduce the spread of infection and define a novel DNA aptamer-based approach to control HSV-1 infection of the eye.

Monitoring influenza hemagglutinin and glycan interactions using surface plasmon resonance.

Hemagglutinin (HA) is a trimeric glycoprotein expressed on the influenza virus membrane. HA of influenza viruses binds to the host's cell surface complex glycans via a terminal sialic acid (Sia), as the first key step in the process of infection, transmission and virulence of influenza viruses. It is important to monitor and evaluate the receptor (glycan) binding preferences of the HAs derived from influenza A viruses, especially those originating from birds and swine, to understand their potential ability for interspecies transmission. From this viewpoint, in the present study, we have developed a protocol for analyzing the glycan-HA interactions efficiently and kinetically, based on surface plasmon resonance (SPR). Our results showed that glycan-HA binding analyses can be performed reliably and efficiently on Biacore-chips in the SPR system, using chemically synthesized biotinylated multivalent-glycans. Using the CAP-chip, we were able to regenerate the surface for multiple analyses, allowing us to derive, for the first time, the precise kinetic parameters for different HA-glycan complexes of newly emerging influenza viruses. These studies suggested that this SPR-based method is suitable for influenza surveillance to define the pandemic scenario as well as to screen of synthetic glycans and other compounds that may interfere with glycan-HA interactions.

In vitro-transcribed Chrysanthemum stunt viroid RNA is infectious to chrysanthemum and other plants.

Chrysanthemum stunt viroid (CSVd), a noncoding RNA, is known to cause chrysanthemum stunt disease, which affects the yield of flowers. To gain insights into CSVd replication, infection, and the reasons for the spreading of CSVd disease in chrysanthemum plants, we prepared linear CSVd RNA and analyzed its ability to cause disease in chrysanthemum plants. We found that linear CSVd replicated as efficiently as CSVd RNA isolated from the infected chrysanthemum plants. Additionally, the linear CSVd RNA was evaluated for its ability to infect other plants as well, which revealed that CSVd has a wide host range for its replication. Importantly, the CSVd isolated from these hosts is infectious to chrysanthemum plants, and thus potentially contributes to the spreading of the disease to chrysanthemum plants.