Codon-optimized MDR3 AAV vector for PFIC3 gene therapy
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Solution Overview
Problem
Current treatments for progressive familial intrahepatic cholestasis type 3 (PFIC3) are inadequate, with no cure available and existing therapies either ineffective or associated with significant side effects and risks.
Innovation Solution
Development of an adeno-associated virus vector carrying a codon-optimized sequence encoding the MDR3 isoform A, which is specifically designed for efficient expression in the canalicular membranes of hepatocytes, thereby addressing the underlying genetic defect causing PFIC3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integrating vector systems are used to correct the defective ABCB4 gene, then stable integration and expression of ABCB4 in liver cells can be achieved, but there is a potential risk of causing insertional mutagenesis
Solution Approach 1:
The patent uses adeno-associated virus (AAV) vectors as intermediary carriers to deliver the corrected ABCB4 gene to liver cells. AAV vectors are non-integrating viral vectors that maintain transgene expression without integrating into the host genome, thus avoiding insertional mutagenesis while achieving stable long-term expression. This intermediary approach resolves the contradiction by providing a safe delivery mechanism that does not directly integrate into host DNA.
Solution Approach 2:
The patent employs non-integrating AAV vectors that function as temporary, non-permanent gene delivery vehicles. These vectors deliver the therapeutic gene without becoming permanently part of the host genome, allowing the therapeutic effect to be achieved without the long-term risks associated with permanent integration. The vectors complete their function and are eventually cleared without causing genetic instability.
2Object-affected harmful factors
If RNA therapy is used to treat PFIC3, then the need for stable integration is avoided, but long-term stable transgene expression is difficult to achieve
Solution Approach 1:
The patent utilizes codon optimization to modify the ABCB4 coding sequence, replacing rare codons with more frequently used codons in human cells. This parameter change in the genetic code enhances translation efficiency and protein expression levels. By optimizing codon usage, the patent achieves sustained long-term expression of the therapeutic protein from the AAV-delivered transgene without requiring integration into the host genome, thus resolving the contradiction between safety and durability.
3Reliability
If liver transplant is performed to treat PFIC3, then effective treatment is achieved, but risks of the procedure and re-emergence of the condition remain
Solution Approach 1:
The patent extracts and corrects only the defective ABCB4 gene responsible for PFIC3, delivering the corrected gene specifically to liver cells using AAV vectors. This targeted approach corrects the underlying genetic defect without requiring removal of the entire liver organ. By extracting and fixing only the problematic genetic element rather than replacing the whole organ, the patent achieves effective treatment while avoiding the significant risks and complications associated with liver transplantation.
4Reliability
If biliary diversion surgery is performed, then patient outcomes improve, but post-surgical complications and reduced quality of life occur
Solution Approach 1:
The patent enables the liver cells to self-correct the genetic defect by delivering the functional ABCB4 gene directly to the hepatocytes. The corrected cells then autonomously produce the MDR3 phospholipid transporter protein, restoring normal phosphatidylcholine secretion into bile without requiring external surgical intervention or ongoing medical management. This self-service approach improves patient outcomes while maintaining quality of life, avoiding the complications and lifestyle restrictions associated with biliary diversion surgery.
Data Source
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AI summary
The present disclosure relates to gene therapy vector for use in the treatment of progressive familiar intrahepatic cholestasis type 3. More specifically, the present invention relates to an adeno-associated virus vector comprising codon-optimized sequence encoding for the MDR3 isoform A for the treatment of PFIC3.