The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca
ABSTRACT The toxigenic Klebsiella oxytoca strains secrete tilymicin and tilivalline enterotoxins, which cause antibiotic-associated hemorrhagic colitis. Both enterotoxins are non-ribosomal peptides synthesized by enzymes encoded in two divergent operons clustered in a pathogenicity island. The trans...
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American Society for Microbiology
2025-01-01
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| Online Access: | https://journals.asm.org/doi/10.1128/msphere.00780-24 |
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| author | Miguel A. De la Cruz Hilda A. Valdez-Salazar Diana Rodríguez-Valverde Santa Mejia-Ventura Nayely Robles-Leyva Tania Siqueiros-Cendón Quintín Rascón-Cruz Nancy León-Montes Jorge Soria-Bustos Fernando Chimal-Cázares Roberto Rosales-Reyes María L. Cedillo Jorge A. Yañez-Santos J. Antonio Ibarra Javier Torres Jorge A. Girón James G. Fox Miguel A. Ares |
| author_facet | Miguel A. De la Cruz Hilda A. Valdez-Salazar Diana Rodríguez-Valverde Santa Mejia-Ventura Nayely Robles-Leyva Tania Siqueiros-Cendón Quintín Rascón-Cruz Nancy León-Montes Jorge Soria-Bustos Fernando Chimal-Cázares Roberto Rosales-Reyes María L. Cedillo Jorge A. Yañez-Santos J. Antonio Ibarra Javier Torres Jorge A. Girón James G. Fox Miguel A. Ares |
| author_sort | Miguel A. De la Cruz |
| collection | DOAJ |
| description | ABSTRACT The toxigenic Klebsiella oxytoca strains secrete tilymicin and tilivalline enterotoxins, which cause antibiotic-associated hemorrhagic colitis. Both enterotoxins are non-ribosomal peptides synthesized by enzymes encoded in two divergent operons clustered in a pathogenicity island. The transcriptional regulator Lrp (leucine-responsive regulatory protein) controls the expression of several bacterial genes involved in virulence. In this work, we have uncovered novel findings that have significant implications. We determined the transcriptional expression of aroX and npsA, the first genes of each tilimycin (TM)/tilivalline (TV) biosynthetic operon in K. oxytoca MIT 09-7231 wild-type and its derivatives Δlrp mutant and complemented strains. Our results suggest that Lrp directly activates the transcription of both aroX and npsA genes by binding to the intergenic regulatory region in a leucine-dependent manner. Furthermore, the lack of Lrp significantly diminished the cytotoxicity of K. oxytoca on HeLa cells due to reduced production of TM and TV. Altogether, our data present a new perspective on the role of Lrp as a regulator in cytotoxin-producing K. oxytoca strains and how it controls the expression of genes involved in the biosynthesis of their main virulence factors.IMPORTANCETilimycin (TM) and tilivalline (TV) are enterotoxins that are a hallmark for the cytotoxin-producing Klebsiella oxytoca strains, which cause antibiotic-associated hemorrhagic colitis. The biosynthesis of TM and TV is driven by enzymes encoded by the aroX- and NRPS-operons. In this study, we discovered that the transcriptional regulator Lrp plays a crucial role in activating the expression of the aroX- and NRPS-operons, thereby initiating TM and TV biosynthesis. Our results underscore a molecular mechanism by which TM and TV production by toxigenic K. oxytoca strains is regulated and shed further light on developing strategies to prevent the intestinal illness caused by this enteric pathogen. |
| format | Article |
| id | doaj-art-39a541ff8d514ea1856f9463d6605cd7 |
| institution | Kabale University |
| issn | 2379-5042 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | American Society for Microbiology |
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| spelling | doaj-art-39a541ff8d514ea1856f9463d6605cd72025-01-28T14:00:56ZengAmerican Society for MicrobiologymSphere2379-50422025-01-0110110.1128/msphere.00780-24The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytocaMiguel A. De la Cruz0Hilda A. Valdez-Salazar1Diana Rodríguez-Valverde2Santa Mejia-Ventura3Nayely Robles-Leyva4Tania Siqueiros-Cendón5Quintín Rascón-Cruz6Nancy León-Montes7Jorge Soria-Bustos8Fernando Chimal-Cázares9Roberto Rosales-Reyes10María L. Cedillo11Jorge A. Yañez-Santos12J. Antonio Ibarra13Javier Torres14Jorge A. Girón15James G. Fox16Miguel A. Ares17Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoFacultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Chihuahua, MexicoFacultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Chihuahua, MexicoFacultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Chihuahua, MexicoUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoCentro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, MexicoInstituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Tulancingo, Hidalgo, MexicoUnidad de Medicina Experimental, Facultad de Medicina, Universidad Autónoma de México, Mexico City, MexicoCentro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, MexicoCentro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, MexicoDepartamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, MexicoUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoCentro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, MexicoDivision of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, USAUnidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, MexicoABSTRACT The toxigenic Klebsiella oxytoca strains secrete tilymicin and tilivalline enterotoxins, which cause antibiotic-associated hemorrhagic colitis. Both enterotoxins are non-ribosomal peptides synthesized by enzymes encoded in two divergent operons clustered in a pathogenicity island. The transcriptional regulator Lrp (leucine-responsive regulatory protein) controls the expression of several bacterial genes involved in virulence. In this work, we have uncovered novel findings that have significant implications. We determined the transcriptional expression of aroX and npsA, the first genes of each tilimycin (TM)/tilivalline (TV) biosynthetic operon in K. oxytoca MIT 09-7231 wild-type and its derivatives Δlrp mutant and complemented strains. Our results suggest that Lrp directly activates the transcription of both aroX and npsA genes by binding to the intergenic regulatory region in a leucine-dependent manner. Furthermore, the lack of Lrp significantly diminished the cytotoxicity of K. oxytoca on HeLa cells due to reduced production of TM and TV. Altogether, our data present a new perspective on the role of Lrp as a regulator in cytotoxin-producing K. oxytoca strains and how it controls the expression of genes involved in the biosynthesis of their main virulence factors.IMPORTANCETilimycin (TM) and tilivalline (TV) are enterotoxins that are a hallmark for the cytotoxin-producing Klebsiella oxytoca strains, which cause antibiotic-associated hemorrhagic colitis. The biosynthesis of TM and TV is driven by enzymes encoded by the aroX- and NRPS-operons. In this study, we discovered that the transcriptional regulator Lrp plays a crucial role in activating the expression of the aroX- and NRPS-operons, thereby initiating TM and TV biosynthesis. Our results underscore a molecular mechanism by which TM and TV production by toxigenic K. oxytoca strains is regulated and shed further light on developing strategies to prevent the intestinal illness caused by this enteric pathogen.https://journals.asm.org/doi/10.1128/msphere.00780-24lrpcitotoxicityaroXnpsAKlebsiella oxytoca |
| spellingShingle | Miguel A. De la Cruz Hilda A. Valdez-Salazar Diana Rodríguez-Valverde Santa Mejia-Ventura Nayely Robles-Leyva Tania Siqueiros-Cendón Quintín Rascón-Cruz Nancy León-Montes Jorge Soria-Bustos Fernando Chimal-Cázares Roberto Rosales-Reyes María L. Cedillo Jorge A. Yañez-Santos J. Antonio Ibarra Javier Torres Jorge A. Girón James G. Fox Miguel A. Ares The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca mSphere lrp citotoxicity aroX npsA Klebsiella oxytoca |
| title | The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca |
| title_full | The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca |
| title_fullStr | The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca |
| title_full_unstemmed | The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca |
| title_short | The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in Klebsiella oxytoca |
| title_sort | transcriptional regulator lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in klebsiella oxytoca |
| topic | lrp citotoxicity aroX npsA Klebsiella oxytoca |
| url | https://journals.asm.org/doi/10.1128/msphere.00780-24 |
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