Lipid-Modified Antisense Oligonucleotides for Bacterial Uptake
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Solution Overview
Problem
Antimicrobial resistance, particularly against third-generation cephalosporins, poses a significant public health issue due to the prevalence of extended-spectrum β-lactamases like CTX-M-15, rendering current antibiotics ineffective, and existing solutions like small drug inhibitors face resistance issues.
Innovation Solution
Development of lipid-modified antisense oligonucleotides that target the blaCTX-M15 gene, enhancing cellular uptake and stability through phosphorothioate chemistry, to specifically reduce the expression of CTX-M extended-spectrum β-lactamases, thereby restoring antibiotic sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antisense oligonucleotides are used to target blaCTX-M15 gene, then gene expression inhibition is achieved, but cellular uptake efficiency is insufficient
Solution Approach 1:
The patent combines antisense oligonucleotides with lipid carriers to create lipid-conjugated antisense oligonucleotides. This composite structure integrates the gene-targeting capability of oligonucleotides with the cell-membrane penetration ability of lipids, thereby improving cellular uptake while maintaining gene expression inhibition function.
Solution Approach 2:
Lipid carriers serve as intermediaries that facilitate the delivery of antisense oligonucleotides into bacterial cells. The lipid component acts as a mediator that enables the oligonucleotide to cross the cell membrane barrier, which otherwise prevents efficient cellular uptake of naked oligonucleotides.
2Reliability
If small drug inhibitors are used to address AMR, then resistance mechanism is targeted, but inhibitor-resistant β-lactamases develop over time
Solution Approach 1:
Instead of directly inhibiting the β-lactamase enzyme, the invention uses antisense oligonucleotides that copy or mimic the target gene sequence to bind complementary mRNA. This indirect approach prevents enzyme production at the transcriptional level, avoiding the selection pressure that leads to inhibitor-resistant enzyme variants.
Solution Approach 2:
The antisense oligonucleotide acts preliminarily by blocking mRNA translation before the β-lactamase enzyme can be synthesized. This preventive mechanism stops resistance enzyme production at an early stage, preventing the development of inhibitor-resistant strains that would otherwise emerge from direct enzyme-inhibitor interactions.
3Adaptability or versatility
If carriers used in mammalian cells are applied to bacterial cells, then delivery mechanism is transferred, but toxicity increases and delivery efficiency decreases
Solution Approach 1:
The invention adapts the carrier properties specifically for bacterial applications by using lipid conjugates with characteristics optimized for prokaryotic cell membranes. Rather than directly transferring mammalian cell carriers, the lipid component is tailored to match bacterial membrane properties, reducing toxicity while maintaining delivery capability.
Solution Approach 2:
The patent modifies key parameters of the delivery system by changing from complex mammalian cell carriers to simplified lipid-conjugated oligonucleotides. This parameter change includes altering the molecular structure, size, and chemical composition to suit bacterial targets, thereby reducing toxicity while preserving delivery function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The lipid-modified antisense oligonucleotides demonstrate a significant decrease in the minimum inhibitory concentration of ceftriaxone against resistant strains, effectively inhibiting β-lactamase production and reversing antibiotic resistance, offering a promising strategy to combat resistant bacteria.
Implementation Method 1
Antisense oligonucleotides (ASO) hybridize with mRNA, which inhibit the expression of the gene responsible of the resistance
Implementation Method 2
these lipid-modified antisense oligonucleotides can show a further improved enzymatic stability with phosphorothioate chemistry (PTO)
Data Source
AI summary
The present invention relates to the treatment of infections due to antibiotic-resistant bacteria. Antimicrobial resistance (AMR) has been observed at dangerously high levels worldwide and alternative strategies are urgently needed. Antisense therapy has been identified as potential therapeutic tool for tackling AMR. However, in the context of AMR, since the antisense oligonucleotides have to reach the target mRNA to be efficient, the cellular uptake inside prokaryotic cells is a critical issue. The inventors demonstrated that antisense oligonucleotide sequences, in particular targeting the blaCTX/M15 gene, featuring a lipid moiety conjugated to the ASO extremity show a particularly efficient intracellular penetration in prokaryotic cells and that these lipid-modified antisense oligonucleotides can show a further improved enzymatic stability with phosphorothioate chemistry (PTO). In particular, the present invention relates to an antisense oligonucleotide modified by substitution at the 5′ or the 3′ end by a lipid moiety, wherein said antisense oligonucleotide specifically targets an mRNA encoding a CTX-M extended spectrum β-lactamase. Another object of the invention concerns the antisense oligonucleotide of the invention for use for treating a bacterial infection, in particular due to bacteria resistant to 3rd generation cephalosporins.