ABSTRACT
The ability to obtain Fe is critical for pathogens to multiply in their host. For this reason, there is significant interest in the identification of compounds that might interfere with Fe management in bacteria. Here we have tested the response of two Gram-negative pathogens, Salmonella enterica serovar Typhimurium (STM) and Pseudomonas aeruginosa (PAO1), to deferiprone (DFP), a chelating agent already in use for the treatment of thalassemia, and to some DFP derivatives designed to increase its lipophilicity. Our results indicate that DFP effectively inhibits the growth of PAO1, but not STM. Similarly, Fe-dependent genes of the two microorganisms respond differently to this agent. DFP is, however, capable of inhibiting an STM strain unable to synthesize enterochelin, while its effect on PAO1 is not related to the capability to produce siderophores. Using a fluorescent derivative of DFP we have shown that this chelator can penetrate very quickly into PAO1, but not into STM, suggesting that a selective receptor exists in Pseudomonas. Some of the tested derivatives have shown a greater ability to interfere with Fe homeostasis in STM compared to DFP, whereas most, although not all, were less active than DFP against PAO1, possibly due to interference of the added chemical tails with the receptor-mediated recognition process. The results reported in this work indicate that DFP can have different effects on distinct microorganisms, but that it is possible to obtain derivatives with a broader antimicrobial action.
Subject(s)
Anti-Infective Agents/pharmacology , Deferiprone/analogs & derivatives , Deferiprone/pharmacology , Iron Chelating Agents/pharmacology , Pseudomonas aeruginosa/drug effects , Salmonella typhimurium/drug effects , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Gene Expression Regulation/drug effects , Iron-Binding Proteins/genetics , Iron-Binding Proteins/metabolism , Sigma Factor/genetics , Sigma Factor/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
The blood-brain barrier (BBB) permeability of molecules needs to meet stringent requirements of Lipinski's rule, which pose a difficulty for the rational design of efficient chelating agents for Parkinson's disease chelation therapy. Therefore, the iron chelators employed N-aliphatic alcohols modification of deferiprone were reasonably designed in this work. The chelators not only meet Lipinski's rule for BBB permeability, but also ensure the iron affinity. The results of solution thermodynamics demonstrated that the pFe3+ value of N-hydroxyalkyl substituted deferiprone is between 19.20 and 19.36, which is comparable to that of clinical deferiprone. The results of 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays indicated that the N-hydroxyalkyl substituted deferiprone also possesses similar radical scavenging ability in comparison to deferiprone. Meanwhile, the Cell Counting Kit-8 assays of neuron-like rat pheochromocytoma cell-line demonstrated that the N-hydroxyalkyl substituted deferiprone exhibits extremely low cytotoxicity and excellent H2O2-induced oxidative stress protection effect. These results indicated that N-hydroxyalkyl substituted deferiprone has potential application prospects as chelating agents for Parkinson's disease chelation therapy strategy.
