Stapled Peptides Inhibit HSV-1 DNA Polymerase Processivity
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Solution Overview
Problem
Current treatments for herpes simplex virus type 1 (HSV-1) infections, particularly herpes keratitis, face challenges due to emerging drug-resistant mutants and the limited effectiveness of existing antiviral drugs, which complicates clinical management and leads to recurrent infections and vision loss.
Innovation Solution
Development of stapled peptides that specifically target the interaction between HSV-1's DNA polymerase and processivity factor, blocking viral DNA synthesis and infection by mimicking the extreme C-terminal α-helix of the DNA polymerase, thereby inhibiting processive DNA synthesis and infection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nucleoside analogue antiviral drugs like acyclovir are used to treat HSV-1 infections, then viral infection is blocked by targeting viral thymidine kinase, but drug-resistant mutants emerge leading to treatment failure
Solution Approach 1:
The patent extracts and isolates the extreme C-terminal α-helix region of the HSV-1 DNA polymerase (residues 1222-1235) to create a stapled peptide inhibitor. This extracted peptide specifically targets the processivity factor interaction site on the DNA polymerase, separating the therapeutic action from the viral thymidine kinase target that leads to resistance. The stapled peptide mimics the native helix structure to disrupt the polymerase-processivity factor interaction essential for viral DNA synthesis.
Solution Approach 2:
The patent introduces a staple (covalent linker) at position 1230-1235 of the DNA polymerase C-terminal helix, transforming the flexible peptide into a rigid stapled structure. This parameter change in molecular conformation enhances binding affinity and stability of the inhibitor to the processivity factor, improving therapeutic effectiveness while maintaining specificity for HSV-1 DNA polymerase.
2Reliability
If trifluridine is used to treat refractory herpes keratitis, then antiviral activity is achieved, but toxicity increases due to non-specific DNA polymerase inhibition
Solution Approach 1:
The stapled peptide is designed with local specificity to the HSV-1 DNA polymerase processivity factor interaction interface. By targeting this specific local region (C-terminal helix residues 1222-1235) rather than the general DNA polymerase active site, the inhibitor achieves selective antiviral activity. This local quality approach allows the drug to inhibit HSV-1 replication while sparing host cellular DNA polymerases, reducing toxicity.
Solution Approach 2:
The stapled peptide acts as an intermediary molecule that binds to the processivity factor on HSV-1 DNA polymerase, blocking the interaction between the viral polymerase and its processivity factor. This intermediary action specifically disrupts viral DNA synthesis without affecting host cell DNA replication machinery, providing selective antiviral therapy with reduced off-target toxicity.
3Reliability
If acyclovir and related inhibitors are used to treat herpes keratitis, then viral infection is blocked, but all drugs target the same herpes TK leading to cross-resistance
Solution Approach 1:
The stapled peptide targets a different functional element of the HSV-1 replication machinery - the DNA polymerase processivity factor interaction - rather than thymidine kinase. This alternative target provides multi-functionality in antiviral therapy, addressing cases where TK-targeting drugs fail due to resistance. The universal approach of targeting essential viral replication functions through multiple different molecular targets expands treatment options.
4Ease of operation
If recurrent HSV-1 infections are left untreated, then natural disease progression occurs, but permanent corneal scarring and vision loss result
Solution Approach 1:
The stapled peptide inhibitor prevents HSV-1 DNA synthesis at an early stage by blocking the polymerase-processivity factor interaction required for viral genome replication. By administering this inhibitor during initial or recurrent infections, the treatment prevents progression to stromal keratitis, corneal scarring, and vision loss. The preliminary action of blocking viral DNA synthesis before immune-mediated damage occurs protects corneal integrity.
Data Source
AI summary
The present disclosure relates generally to stapled peptides, and pharmaceutical compositions thereof, which are useful for preventing and/or treating herpes simplex virus-1 (HSV-1) processive DNA synthesis, propagation, and/or infection in a subject. The present disclosure further provides methods for treating herpes simplex keratitis in a subject