ADAMTS13 Transgene Truncation for AAV-Limited Gene Therapy
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Solution Overview
Problem
The large size of the gene encoding for ADAMTS13 (about 4.3 kilobases) exceeds the packaging capacity of AAV, limiting its use in gene therapy, and current truncated variants lack critical regulatory domains for fine-tuned proteolytic activity.
Innovation Solution
A gene therapy plasmid encoding variants of ADAMTS13, comprising specific domains for autoregulation and regulatory elements, is developed to fit within AAV packaging limits while maintaining full functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the full-length ADAMTS13 gene (4.3 kilobases) is used for gene therapy, then the therapeutic functionality is complete, but the gene size exceeds the AAV packaging capacity (4.5-4.8 kilobases)
Solution Approach 1:
The patent applies segmentation by dividing the ADAMTS13 gene into critical functional domains (proximal thrombospondin domain, distal thrombospondin domains, CUB domains) and selecting only the essential ones needed for packaging within AAV capacity while maintaining therapeutic activity. This allows the gene to be truncated to fit packaging limits without losing core function.
Solution Approach 2:
The patent extracts and removes non-essential domains from the full-length ADAMTS13 gene, specifically eliminating redundant thrombospondin domains (T3-T6) while retaining critical domains (T1, T2, T7, T8, CUB1, CUB2) necessary for enzymatic activity and regulation, thereby reducing gene size to fit AAV packaging capacity.
2Length of stationary object
If a truncated version of ADAMTS13 (MDTCS variant) is used to fit AAV packaging capacity, then the gene size is reduced, but the regulatory protein domain responsible for fine-tuned modulation of proteolytic activity is lost
Solution Approach 1:
The patent applies local quality by selectively retaining specific domains with distinct functional properties: proximal thrombospondin domain (T1) and distal thrombospondin domains (T2, T7, T8) are kept for structural integrity and regulatory functions, while intermediate domains (T3-T6) are removed. The CUB domains are retained to maintain proteolytic activity. This localized selection preserves regulatory capacity within size constraints.
Solution Approach 2:
The patent changes the gene structure parameters by deleting specific domain regions (T3-T6) while preserving others, creating a customized truncated version that fits AAV packaging limits. The resulting gene has modified domain composition that maintains both enzymatic activity and regulatory protein domain functions necessary for fine-tuned proteolytic modulation.
3Ease of operation
If standard care treatments are provided to cTTP patients, then immediate symptom management is achieved, but the long-term survival rate remains low (10-20% death risk)
Solution Approach 1:
The patent applies preliminary action by administering AAV-mediated gene therapy before the development of severe, irreversible complications. The therapy establishes long-term ADAMTS13 expression in the patient's liver, preventing future TTP episodes and improving long-term survival. This proactive approach differs from reactive standard care that treats symptoms after they manifest.
Solution Approach 2:
The patent enables continuity of useful action through long-term expression of ADAMTS13 in the patient's circulation, achieved by establishing permanent transgene expression in liver cells. This continuous production of functional ADAMTS13 prevents recurrent thrombotic events, providing sustained therapeutic benefit rather than temporary symptom management.
Data Source
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AI summary
The present invention provides gene therapy plasmids and transgenes comprising a variant of ADAMTS13, recombinant virus vectors for delivery of said viral plasmids and transgenes and medical uses relating to the treatment of ADAMTS13 insufficiency.