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Updated: Jul 16, 2026
Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
Published on: March 16, 2017
Nitric oxide production and nitric oxide synthase immunoreactivity in Naegleria fowleri
Saúl Rojas-Hernández1, Marco A Rodríguez-Monroy, Leticia Moreno-Fierros
1Departamento de Investigación y Posgrado, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luís y Díaz Mirón, 11340, México, D.F., Mexico. saulrohe@yahoo.com.mx
Abstract:
Free-living ameba Naegleria fowleri produces an acute and fatal infectious disease called primary amebic meningoencephalitis (PAM), whose pathophysiological mechanism is largely unknown. The aim of this study was to investigate the role of nitric oxide (NO) in PAM. Although NO has a cytotoxic effect on various parasites, it is produced by others as part of the pathology, as is the case with Entamoeba histolytica. To test for the production of NO, we analyzed whether antibodies against mammalian NO synthase isoforms (neuronal, inducible, and endothelial) presented immunoreactivity to N. fowleri proteins. We found that the trophozoites produced NO in vitro. The Western blot results, which showed N. fowleri trophozoites, contained proteins that share epitopes with the three described mammalian NOS, but have relative molecular weights different than those described in the literature, suggesting that N. fowleri may contain undescribed NOS isoforms. Moreover, we found that trophozoites reacted to the NOS2 antibody, in amebic cultures as well as in the mouse brain infected with N. fowleri, suggesting that nitric oxide may participate in the pathogenesis of PAM. Further research aimed at determining whether N. fowleri contains active novel NOS isoforms could lead to the design of new therapies against this parasite.
Insights
Naegleria fowleri, the cause of primary amebic meningoencephalitis (PAM), produces nitric oxide (NO). This finding suggests NO may play a role in PAM pathogenesis and could inform new treatment strategies.
Area of Science:
- Parasitology
- Immunology
- Biochemistry
Background:
- Naegleria fowleri causes fatal primary amebic meningoencephalitis (PAM).
- The pathophysiological mechanisms of PAM remain largely unknown.
- Nitric oxide (NO) has complex roles in parasitic infections, acting as both a defense mechanism and a factor in disease pathology.
Purpose of the Study:
- To investigate the potential role of nitric oxide (NO) in the pathogenesis of primary amebic meningoencephalitis (PAM).
- To determine if Naegleria fowleri produces NO and identify potential nitric oxide synthase (NOS) enzymes within the parasite.
Main Methods:
- Analysis of immunoreactivity between antibodies against mammalian NOS isoforms (neuronal, inducible, endothelial) and N. fowleri proteins using Western blot.
- In vitro assessment of NO production by N. fowleri trophozoites.
- Detection of NOS activity in amebic cultures and infected mouse brains.
Main Results:
- N. fowleri trophozoites were confirmed to produce NO in vitro.
- Western blot analysis revealed N. fowleri proteins sharing epitopes with mammalian NOS, but with different molecular weights, suggesting novel NOS isoforms.
- Trophozoites exhibited reactivity to the NOS2 antibody in both culture and infected mouse brain models.
Conclusions:
- Naegleria fowleri produces nitric oxide, indicating its potential involvement in PAM pathogenesis.
- The parasite likely possesses unique NOS isoforms, distinct from known mammalian counterparts.
- Further research into these novel NOS isoforms could pave the way for developing targeted therapies against N. fowleri infections.
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