A hydrocarbon-stapled peptide targeting HSV-1's processivity factor specifically blocked herpes DNA synthesis and infection in human corneal cells with a selectivity index of 11.6, offering a new approach for drug-resistant herpes keratitis.
Selectivity index 11.6The optimized di-valine stapled peptide blocked HSV-1 infection in human corneal cells with meaningful selectivity — a foundation for topical herpes keratitis treatment
What the researchers found
Optimized di-valine stapled peptide blocked HSV-1 DNA synthesis and infection in human primary corneal epithelial cells with selectivity index of 11.6. Unstapled control peptide had no effect. Peptide did not block unrelated virus infection (specificity confirmed).
Why it matters
Acyclovir-resistant herpes is a growing clinical problem, especially for eye infections that can cause blindness. A peptide targeting a completely different viral protein provides a fallback treatment option.
The numbers in context
Selectivity index 11.6; di-valine optimization; specific to HSV-1; unstapled control had no effect
How the study worked
Structure-based peptide design from HSV-1 polymerase C-terminus crystal structure. Hydrocarbon stapling to maintain α-helical conformation. Testing of DNA synthesis inhibition, HSV-1 infection blocking, and specificity in human primary corneal epithelial cells.
Who was studied
Human primary corneal epithelial cells infected with HSV-1
What this study cannot tell us
In vitro study in human corneal cells only. Selectivity index of 11.6 is modest for drug development. Topical eye formulation, stability, and penetration not tested. In vivo efficacy in animal models of herpes keratitis not assessed.
How to read the evidence
Low evidence grade: in vitro proof-of-concept in human primary cells. No animal or clinical data. Selectivity index needs improvement for drug development.
When this study was published
Published 2021. Stapled peptide antivirals are a growing research area with increasing pharmaceutical interest.
The bigger picture
Stapled peptides are proving versatile across therapeutic areas. This application — blocking a viral enzyme's protein-protein interaction — demonstrates their potential in antiviral medicine, where protein interactions are often "undruggable" by conventional small molecules.
Questions still open
- Can the peptide be formulated as stable eye drops for clinical use?
- Would this peptide work against acyclovir-resistant HSV-1 strains specifically?
- Could similar stapled peptides target processivity factors of other herpesviruses?
Common questions
What is herpes keratitis?
Why use a stapled peptide instead of regular antiviral drugs?
Read the original research
Herpes Simplex Virus-1 infection in human primary corneal epithelial cells is blocked by a stapled peptide that targets processive DNA synthesis.
The ocular surface, 19, 313-321
Citation
Guan, Hancheng; Nuth, Manunya; Lee, Vivian; Lin, Chenyan; Mitchell, Claire H; Lu, Wennan; Scott, Richard W; Parker, Michael H; Kulp, John L; Reitz, Allen B; Ricciardi, Robert P. (2021). Herpes Simplex Virus-1 infection in human primary corneal epithelial cells is blocked by a stapled peptide that targets processive DNA synthesis.. The ocular surface, 19, 313-321. https://doi.org/10.1016/j.jtos.2020.11.001