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Epithelial Cell Infection Analyses with Shigella
Published on: February 9, 2024
Modulación de la virulencia de Shigella en respuesta al oxígeno disponible in vivo
Benoit Marteyn1, Nicholas P West, Douglas F Browning
1Centre for Molecular Microbiology and Infection, Department of Microbiology, Flowers Building, Imperial College London, London SW7 2AZ, UK.
Nature
|May 4, 2010
Resumen
Las bacterias Shigella flexneri usan los niveles de oxígeno para controlar su virulencia. En bajos niveles de oxígeno, se preparan para invadir extendiendo las agujas de secreción, pero reducen la liberación del efector, mejorando la invasión cerca del revestimiento intestinal.
Área de la Ciencia:
- Microbiología Microbiología.
- La patogénesis bacteriana es la patogénesis bacteriana.
- Interacciones huésped-patógeno.
Sus antecedentes:
- Las bacterias coordinan la expresión del factor de virulencia en función de los microambientes del huésped.
- Shigella flexneri causa disentería y depende de su sistema de secreción de tipo tres (T3SS) para la invasión y la virulencia.
- Los niveles de oxígeno en el tracto gastrointestinal influyen en el comportamiento bacteriano.
Objetivo del estudio:
- Para investigar cómo la concentración de oxígeno afecta la actividad del sistema de secreción de tipo tres (T3SS) de Shigella flexneri.
- Para aclarar los mecanismos reguladores que controlan la función T3SS en respuesta a los diferentes niveles de oxígeno.
- Comprender el papel del oxígeno en la mediación de la invasión y virulencia de Shigella dentro del tracto gastrointestinal del huésped.
Principales métodos:
- Análisis de la expresión génica bacteriana bajo diferentes condiciones de oxígeno (anaeróbico vs. oxigenación relativa).
- Investigando el papel del regulador FNR (reducción de fumarato y nitrato) en el control de la transcripción del gen de virulencia.
- Examinando el impacto de la regulación mediada por oxígeno en la extensión de la aguja T3SS y la secreción del efector (Ipa).
Principales resultados:
- Condiciones anaerobias en el lumen intestinal priman a Shigella para la invasión mediante la extensión de las agujas T3SS, pero reprimen la secreción del efector Ipa a través del control mediado por FNR de spa32 y spa33.
- Una zona de oxigenación relativa cerca de la mucosa del tracto gastrointestinal invierte el bloqueo anaeróbico en la secreción de Ipa.
- Este gradiente de oxígeno permite la activación precisa de T3SS en el sitio de contacto con la célula huésped, mejorando la invasión y la virulencia.
Conclusiones:
- La concentración de oxígeno es una señal ambiental crítica que modula la virulencia de Shigella flexneri.
- El regulador de FNR juega un papel clave en la vinculación del metabolismo anaeróbico a la regulación de T3SS.
- Los diferentes niveles de oxígeno dentro del tracto gastrointestinal facilitan la invasión bacteriana dirigida y la patogénesis.
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