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Methyl-hydroxylamine as an efficacious antibacterial agent that targets the ribonucleotide reductase enzyme.

Julián E, Baelo A, Gavaldà J, Torrents E - PLoS ONE (2015)

Bottom Line: RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity.M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa.Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm.

View Article: PubMed Central - PubMed

Affiliation: Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.

ABSTRACT
The emergence of multidrug-resistant bacteria has encouraged vigorous efforts to develop antimicrobial agents with new mechanisms of action. Ribonucleotide reductase (RNR) is a key enzyme in DNA replication that acts by converting ribonucleotides into the corresponding deoxyribonucleotides, which are the building blocks of DNA replication and repair. RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity. However, the high toxicity of these current drugs to eukaryotic cells does not permit their use as antibacterial agents. Here, we present a radical scavenger compound that inhibited bacterial RNR, and the compound's activity as an antibacterial agent together with its toxicity in eukaryotic cells were evaluated. First, the efficacy of N-methyl-hydroxylamine (M-HA) in inhibiting the growth of different Gram-positive and Gram-negative bacteria was demonstrated, and no effect on eukaryotic cells was observed. M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa. Thus, given the M-HA activity against these two bacteria, our results showed that M-HA has intracellular antimycobacterial activity against BCG-infected macrophages, and it is efficacious in partially disassembling and inhibiting the further formation of P. aeruginosa biofilms. Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm. Overall, our results suggest the vast potential of M-HA as an antibacterial agent, which acts by specifically targeting a bacterial RNR enzyme.

No MeSH data available.


Related in: MedlinePlus

TNF-α and IL-12 production as triggered by BCG-infected macrophages that were treated with different doses of HU, HA and M-HA.J774 macrophages were infected with BCG and treated with different concentrations of radical scavenger compounds, and TNF-α and IL-12 levels were measured 24 hours post-infection. The results represent the means ± SD of triplicate preparations with one representative of two independent experiments. A Mann-Whitney test was performed (*, P < 0.01; versus non-treated macrophages (control)). HU, hydroxyurea; HA, hydroxylamine; and M-HA, methyl-hydroxylamine.
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pone.0122049.g004: TNF-α and IL-12 production as triggered by BCG-infected macrophages that were treated with different doses of HU, HA and M-HA.J774 macrophages were infected with BCG and treated with different concentrations of radical scavenger compounds, and TNF-α and IL-12 levels were measured 24 hours post-infection. The results represent the means ± SD of triplicate preparations with one representative of two independent experiments. A Mann-Whitney test was performed (*, P < 0.01; versus non-treated macrophages (control)). HU, hydroxyurea; HA, hydroxylamine; and M-HA, methyl-hydroxylamine.

Mentions: We investigated the production of two bactericidal products that are able to kill intracellular BCG, namely TNF-α and NO [24], when the macrophages were infected with BCG and treated with the different radical scavenger compounds. As shown in Fig. 4, M-HA-treated macrophages produce higher TNF-α values at 24 hours post-infection than untreated cells (Fig. 4A). The highest amount of cytokine production was observed when cells were treated with high concentrations of M-HA (Fig. 4A). The amount of cytokine production did not increase after longer periods of incubation (72 or 120 hours after infection) (data not shown). When TNF-α production was evaluated in non-infected cultures, similar values were obtained in radical scavenger-treated and non-treated macrophages (data not shown).


Methyl-hydroxylamine as an efficacious antibacterial agent that targets the ribonucleotide reductase enzyme.

Julián E, Baelo A, Gavaldà J, Torrents E - PLoS ONE (2015)

TNF-α and IL-12 production as triggered by BCG-infected macrophages that were treated with different doses of HU, HA and M-HA.J774 macrophages were infected with BCG and treated with different concentrations of radical scavenger compounds, and TNF-α and IL-12 levels were measured 24 hours post-infection. The results represent the means ± SD of triplicate preparations with one representative of two independent experiments. A Mann-Whitney test was performed (*, P < 0.01; versus non-treated macrophages (control)). HU, hydroxyurea; HA, hydroxylamine; and M-HA, methyl-hydroxylamine.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4363900&req=5

pone.0122049.g004: TNF-α and IL-12 production as triggered by BCG-infected macrophages that were treated with different doses of HU, HA and M-HA.J774 macrophages were infected with BCG and treated with different concentrations of radical scavenger compounds, and TNF-α and IL-12 levels were measured 24 hours post-infection. The results represent the means ± SD of triplicate preparations with one representative of two independent experiments. A Mann-Whitney test was performed (*, P < 0.01; versus non-treated macrophages (control)). HU, hydroxyurea; HA, hydroxylamine; and M-HA, methyl-hydroxylamine.
Mentions: We investigated the production of two bactericidal products that are able to kill intracellular BCG, namely TNF-α and NO [24], when the macrophages were infected with BCG and treated with the different radical scavenger compounds. As shown in Fig. 4, M-HA-treated macrophages produce higher TNF-α values at 24 hours post-infection than untreated cells (Fig. 4A). The highest amount of cytokine production was observed when cells were treated with high concentrations of M-HA (Fig. 4A). The amount of cytokine production did not increase after longer periods of incubation (72 or 120 hours after infection) (data not shown). When TNF-α production was evaluated in non-infected cultures, similar values were obtained in radical scavenger-treated and non-treated macrophages (data not shown).

Bottom Line: RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity.M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa.Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm.

View Article: PubMed Central - PubMed

Affiliation: Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.

ABSTRACT
The emergence of multidrug-resistant bacteria has encouraged vigorous efforts to develop antimicrobial agents with new mechanisms of action. Ribonucleotide reductase (RNR) is a key enzyme in DNA replication that acts by converting ribonucleotides into the corresponding deoxyribonucleotides, which are the building blocks of DNA replication and repair. RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity. However, the high toxicity of these current drugs to eukaryotic cells does not permit their use as antibacterial agents. Here, we present a radical scavenger compound that inhibited bacterial RNR, and the compound's activity as an antibacterial agent together with its toxicity in eukaryotic cells were evaluated. First, the efficacy of N-methyl-hydroxylamine (M-HA) in inhibiting the growth of different Gram-positive and Gram-negative bacteria was demonstrated, and no effect on eukaryotic cells was observed. M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa. Thus, given the M-HA activity against these two bacteria, our results showed that M-HA has intracellular antimycobacterial activity against BCG-infected macrophages, and it is efficacious in partially disassembling and inhibiting the further formation of P. aeruginosa biofilms. Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm. Overall, our results suggest the vast potential of M-HA as an antibacterial agent, which acts by specifically targeting a bacterial RNR enzyme.

No MeSH data available.


Related in: MedlinePlus