Small Molecule PPO Activators for Anaerobic Infection Treatment
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Solution Overview
Problem
Current strategies for combating antibiotic-resistant bacterial infections, such as those caused by Staphylococcus aureus, are limited by the inability to target pathways conditionally required during infection, and existing small molecule screening methods have not identified effective therapeutics that target central metabolism.
Innovation Solution
Development of compounds that activate the enzyme protoporphyrinogen oxidase (PPO) and the heme sensor system (HssRS) to modulate heme biosynthesis and toxicity, allowing for the identification of novel antimicrobial agents that target the heme biosynthetic pathway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small molecule screening strategies based on growth inhibition are used, then traditional antibiotic targets are identified, but pathways conditionally required during infection cannot be targeted
Solution Approach 1:
Instead of screening for compounds that inhibit bacterial growth directly, the patent inverts the approach by screening for compounds that activate heme biosynthesis pathways. This is achieved by using a reporter system where activation of the HssRS two-component system (which responds to heme accumulation) drives expression of a fluorescent reporter gene. Compounds that cause fluorescence indicate activation of heme biosynthesis, providing a reverse selection strategy that identifies inhibitors of central metabolism rather than traditional growth inhibition targets.
2Productivity
If heme biosynthesis is activated to treat infection, then bacterial growth is inhibited under anaerobic conditions, but heme toxicity may increase
Solution Approach 1:
The patent exploits the dual nature of heme as both essential and toxic to bacteria. By activating heme biosynthesis through PPO activation and HssRS system stimulation, the patent creates heme accumulation that triggers a feedback response. The bacteria's own heme sensor system (HssRS) detects the accumulated heme and activates efflux pumps to export excess heme, converting the potentially harmful heme accumulation into a therapeutic mechanism that selectively kills anaerobic bacteria while allowing aerobic bacteria to regulate heme levels normally.
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 compounds effectively activate HssRS, leading to increased heme biosynthesis, alleviating heme toxicity and inhibiting bacterial growth, particularly under anaerobic conditions, providing a new approach to treating antibiotic-resistant infections.
Implementation Method 1
Development of compounds that activate the enzyme protoporphyrinogen oxidase (PPO) and the heme sensor system (HssRS) to modulate heme biosynthesis
Implementation Method 2
HssS is a transmembrane histidine kinase that senses toxic levels of heme through an undetermined mechanism
Implementation Method 3
Upon activation, HssS autophosphorylates and transfers the phosphate to an aspartate residue of its cognate response regulator, HssR
Implementation Method 4
HssR is a cytoplasmic protein which, upon phosphorylation by HssS, binds the direct repeat of the promoter for the heme regulated transporter (hrtAB), a gene encoding an efflux pump that alleviates heme toxicity
Data Source
AI summary
A method for treating a microbial infection involves administering an effective amount of a compound of the formula:wherein R1 is H, alkyl, aryl, heteroaryl, R2 is H, halogen, alkyl, aryl, heteroaryl, R3 is H, hydroxyl, alkoxy, alkyl, aryl, heteroaryl, amino, amino sulfonyl, acetamide, R4 is H, hydroxyl, alkoxy, alkyl, aryl, heteroaryl, amino, amino sulfonyl, acetamide, R5 is H, hydroxyl, alkoxy, alkyl, aryl, heteroaryl, amino, amino sulfonyl, acetamide, R6 is H, hydroxyl, alkoxy, alkyl, aryl, heteroaryl, amino, amino sulfonyl, acetamide, R7 is H, hydroxyl, alkoxy, alkyl, aryl, heteroaryl, amino, amino sulfonyl, acetamide, R8 is —CR3, O, S, wherein R5 and R6, R7 and R6, R5 and R4, R4 and R3 can cyclize forming a 3-10 member ring comprising C, O, S, and/or N optionally substituted with one or more R3; and administering light therapy, such as a photodynamic therapy (PDT) light source.