Regulation of herpes simplex virus type 1 latency-reactivation cycle and ocular disease by cellular signaling pathways

Retinoic Acid Neutralizes the Effects of Herpes Simplex Virus Type 1-Infected Cell Protein 0 (ICP0) in Retinal Pigment Epithelial Cells

BACKGROUND

Herpes simplex virus (HSV) infection of the cornea, uvea, and retina is the leading infectious cause of blindness worldwide. This study examined the effects of retinoic acid (RA) on the protein levels of interleukin (IL)-17A and IL-23 cytokines with known proinflammatory effects and toll-like receptor 3 (TLR3) messenger RNA (mRNA) expression in retinal pigment epithelial (ARPE-19) cells treated with HSV-1-infected cell protein 0 (ICP0).

METHODOLOGY

We used 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyl tetrazolium bromide assay to calculate the half maximal inhibitory concentration (IC50) doses of RA and ICP0 in ARPE-19 cells. At the end of 24 hours, protein levels of IL-17A and IL-23 were analyzed using enzyme-linked immunosorbent assay. TLR3 mRNA expression levels were also calculated using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

RA administration decreased IL-17A levels, which were elevated by ICP0. The IL-23 levels were similar between the ICP0-treated and control groups, but the difference was significant between the ICP0-treated group and RA+ICP0 combination. These results showed that RA can significantly increase IL-23 levels in the presence of ICP0. Although ICP0 dramatically increased TLR3 mRNA expression compared with that in the control group, the RA+ICP0 combination returned TLR3 mRNA expression to a level similar to that in the control group (P = 0.419).

CONCLUSIONS

RA may potentially neutralize HSV-1 ICP0 negative effects in ARPE-19 cells.

Flavonoids with Anti-Herpes Simplex Virus Properties: Deciphering Their Mechanisms in Disrupting the Viral Life Cycle

The herpes simplex virus (HSV) is a double-stranded DNA human virus that causes persistent infections with recurrent outbreaks. HSV exists in two forms: HSV-1, responsible for oral herpes, and HSV-2, primarily causing genital herpes. Both types can lead to significant complications, including neurological issues. Conventional treatment, involving acyclovir and its derivatives, faces challenges due to drug resistance. This underscores the imperative for continual research and development of new drugs, with a particular emphasis on exploring the potential of natural antivirals. Flavonoids have demonstrated promise in combating various viruses, including those within the herpesvirus family. This review, delving into recent studies, reveals the intricate mechanisms by which flavonoids decode their antiviral capabilities against HSV. By disrupting key stages of the viral life cycle, such as attachment to host cells, entry, DNA replication, latency, and reactivation, flavonoids emerge as formidable contenders in the ongoing battle against HSV infections.