Modified PDGFRα Receptors for Selective CMV Trimer Binding
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Solution Overview
Problem
Current antiviral therapies for human cytomegalovirus (CMV) are limited, especially for preventing congenital infections, and there is a need for effective therapeutic agents that can inhibit CMV replication without disrupting essential physiological signaling through platelet-derived growth factor receptor alpha (PDGFRα).
Innovation Solution
Modified PDGFRα polypeptides that retain binding to the CMV trimer but exhibit reduced binding to PDGF ligands, allowing for the development of diagnostic and therapeutic agents to inhibit CMV replication and spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type PDGFRα is used to bind CMV trimer, then CMV binding capacity is maintained, but PDGF ligand binding is not selectively reduced
Solution Approach 1:
The patent applies local quality by introducing specific amino acid substitutions at particular positions (e.g., L137, L208, V242, Y273) within the PDGFRα protein structure. These localized changes modify the binding interface properties to reduce PDGF affinity while preserving CMV trimer binding, thereby achieving selective binding characteristics without altering the entire protein structure.
Solution Approach 2:
The patent employs parameter changes by systematically varying amino acid residues at key binding positions through site-directed mutagenesis. By changing specific physical-chemical properties of amino acids (e.g., hydrophobicity, charge, steric bulk) at defined positions, the binding parameters for PDGF are reduced while maintaining or enhancing CMV trimer binding affinity.
2Reliability
If antiviral therapies are developed to inhibit CMV replication, then CMV infection is treated, but toxicity and drug resistance issues arise
Solution Approach 1:
The patent uses modified PDGFRα polypeptides as intermediary molecules that specifically bind to the CMV trimer (gH/gL/gO complex) to block viral entry into host cells. This intermediary approach provides antiviral protection through a novel mechanism that does not rely on conventional antiviral drugs, thereby avoiding associated toxicity and resistance problems.
Solution Approach 2:
The patent creates modified versions (copies) of the natural PDGFRα receptor with altered binding properties. These engineered polypeptide copies retain the ability to bind CMV trimer while lacking normal PDGF signaling function, providing a safer therapeutic alternative to conventional antivirals.
3Productivity
If PDGFRα is used as a therapeutic agent against CMV, then CMV replication is inhibited, but PDGF signaling is disrupted
Solution Approach 1:
The patent applies segmentation by using soluble extracellular domains of PDGFRα (lacking the intracellular signaling portion) as therapeutic agents. This segmentation allows the polypeptides to bind CMV trimer and inhibit viral entry without possessing transmembrane or intracellular signaling capabilities, thereby preventing disruption of normal PDGF signaling pathways.
Solution Approach 2:
The patent extracts and utilizes only the CMV-binding functional domain of PDGFRα (the extracellular region that binds gH/gL/gO trimer) while removing or disabling the PDGF signaling functionality. This extraction approach enables selective anti-CMV activity without interfering with physiological PDGF receptor signaling.
Data Source
AI summary
Modified platelet-derived growth factor receptor alpha (PDGFRα) polypeptides are described. The modified polypeptides include at least one amino acid substitution that allows the polypeptide to retain the capacity to bind a cytomegalovirus (CMV) trimer comprised of glycoprotein H (gH), gL and gO, but leads to reduced binding to one or more platelet-derived growth factor (PDGF) ligands. Use of the modified PDGFRα polypeptides for inhibiting CMV replication and/or spread, or treating a CMV infection, is also described.