Gastrointestinal microbes respond to biochemical metabolites that coordinate their behaviors. Here, we demonstrate that bacterial indole functions as a multifactorial mitigator of Klebsiella grimontii and Klebsiella oxytoca pathogenicity. These closely related microbes produce the enterotoxins tilimycin and tilivalline; cytotoxin-producing strains are the causative agent of antibiotic-associated hemorrhagic colitis and have been associated with necrotizing enterocolitis of premature infants. We demonstrate that carbohydrates induce cytotoxin synthesis while concurrently repressing indole biosynthesis. Conversely, indole represses cytotoxin production. In both cases, the alterations stemmed from differential transcription of npsA and npsB, key genes involved in tilimycin biosynthesis. Indole also enhances conversion of tilimycin to tilivalline, an indole analog with reduced cytotoxicity. In this context, we established that tilivalline, but not tilimycin, is a strong agonist of pregnane X receptor (PXR), a master regulator of xenobiotic detoxification and intestinal inflammation. Tilivalline binding upregulated PXR-responsive detoxifying genes and inhibited tubulin-directed toxicity. Bacterial indole, therefore, acts in a multifunctional manner to mitigate cytotoxicity by Klebsiella spp.: suppression of toxin production, enhanced conversion of tilimycin to tilivalline, and activation of PXR. IMPORTANCE The human gut harbors a complex community of microbes, including several species and strains that could be commensals or pathogens depending on context. The specific environmental conditions under which a resident microbe changes its relationship with a host and adopts pathogenic behaviors, in many cases, remain poorly understood. Here, we describe a novel communication network involving the regulation of K. grimontii and K. oxytoca enterotoxicity. Bacterial indole was identified as a central modulator of these colitogenic microbes by suppressing bacterial toxin (tilimycin) synthesis and converting tilimycin to tilivalline while simultaneously activating a host receptor, PXR, as a means of mitigating tissue cytotoxicity. On the other hand, fermentable carbohydrates were found to inhibit indole biosynthesis and enhance toxin production. This integrated network involving microbial, host, and metabolic factors provides a contextual framework to better understand K. oxytoca complex pathogenicity.

Center for Environmental Sciences and Engineering University of Connecticut Storrs Connecticut USA

Department of Cell Biology and Genetics Faculty of Science Palacky University Olomouc Czech Republic

Department of Genetics and Genome Sciences UConn Health Farmington Connecticut USA

Department of Immunology UConn Health Farmington Connecticut USA

Department of Medicine Molecular Pharmacology and Genetics Albert Einstein College of Medicine Bronx New York USA

Department of Medicine UConn Health Farmington Connecticut USA

Department of Microbiology and Immunology Drexel University Philadelphia Pennsylvania USA

Department of Molecular Biology and Biophysics UConn Health Farmington Connecticut USA

Department of Pediatrics UConn Health Farmington Connecticut USA

Division of Neonatology Connecticut Children's Medical Center Hartford Connecticut USA

Institute of Molecular Biosciences University of Grazgrid 5110 5 BioTechMed Graz Graz Austria

The Jackson Laboratory for Genomic Medicine Farmington Connecticut USA

000      

00000naa a2200000 a 4500

001      

bmc23004941

003      

CZ-PrNML

005      

20230425171819.0

007      

ta

008      

230418s2022 xxu f 000 0|eng||

009      

AR

024    7_

$a 10.1128/mbio.03752-21 $2 doi

035    __

$a (PubMed)35073747

040    __

$a ABA008 $b cze $d ABA008 $e AACR2

041    0_

$a eng

044    __

$a xxu

100    1_

$a Ledala, Nagender $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA

245    10

$a Bacterial Indole as a Multifunctional Regulator of Klebsiella oxytoca Complex Enterotoxicity / $c N. Ledala, M. Malik, K. Rezaul, S. Paveglio, A. Provatas, A. Kiel, M. Caimano, Y. Zhou, J. Lindgren, K. Krasulova, P. Illes, Z. Dvořák, S. Kortagere, S. Kienesberger, A. Cosic, L. Pöltl, EL. Zechner, S. Ghosh, S. Mani, JD. Radolf, AP. Matson

520    9_

$a Gastrointestinal microbes respond to biochemical metabolites that coordinate their behaviors. Here, we demonstrate that bacterial indole functions as a multifactorial mitigator of Klebsiella grimontii and Klebsiella oxytoca pathogenicity. These closely related microbes produce the enterotoxins tilimycin and tilivalline; cytotoxin-producing strains are the causative agent of antibiotic-associated hemorrhagic colitis and have been associated with necrotizing enterocolitis of premature infants. We demonstrate that carbohydrates induce cytotoxin synthesis while concurrently repressing indole biosynthesis. Conversely, indole represses cytotoxin production. In both cases, the alterations stemmed from differential transcription of npsA and npsB, key genes involved in tilimycin biosynthesis. Indole also enhances conversion of tilimycin to tilivalline, an indole analog with reduced cytotoxicity. In this context, we established that tilivalline, but not tilimycin, is a strong agonist of pregnane X receptor (PXR), a master regulator of xenobiotic detoxification and intestinal inflammation. Tilivalline binding upregulated PXR-responsive detoxifying genes and inhibited tubulin-directed toxicity. Bacterial indole, therefore, acts in a multifunctional manner to mitigate cytotoxicity by Klebsiella spp.: suppression of toxin production, enhanced conversion of tilimycin to tilivalline, and activation of PXR. IMPORTANCE The human gut harbors a complex community of microbes, including several species and strains that could be commensals or pathogens depending on context. The specific environmental conditions under which a resident microbe changes its relationship with a host and adopts pathogenic behaviors, in many cases, remain poorly understood. Here, we describe a novel communication network involving the regulation of K. grimontii and K. oxytoca enterotoxicity. Bacterial indole was identified as a central modulator of these colitogenic microbes by suppressing bacterial toxin (tilimycin) synthesis and converting tilimycin to tilivalline while simultaneously activating a host receptor, PXR, as a means of mitigating tissue cytotoxicity. On the other hand, fermentable carbohydrates were found to inhibit indole biosynthesis and enhance toxin production. This integrated network involving microbial, host, and metabolic factors provides a contextual framework to better understand K. oxytoca complex pathogenicity.

650    _2

$a lidé $7 D006801

650    _2

$a novorozenec $7 D007231

650    _2

$a Klebsiella oxytoca $x genetika $x metabolismus $7 D041121

650    _2

$a enterotoxiny $x metabolismus $7 D004768

650    12

$a pseudomembranózní enterokolitida $x mikrobiologie $7 D004761

650    12

$a infekce bakteriemi rodu Klebsiella $x mikrobiologie $7 D007710

650    _2

$a cytotoxiny $x metabolismus $7 D003603

650    _2

$a indoly $x metabolismus $7 D007211

655    _2

$a časopisecké články $7 D016428

655    _2

$a práce podpořená grantem $7 D013485

655    _2

$a Research Support, U.S. Gov't, Non-P.H.S. $7 D013486

700    1_

$a Malik, Mishika $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA $u Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA

700    1_

$a Rezaul, Karim $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA

700    1_

$a Paveglio, Sara $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA $u Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA

700    1_

$a Provatas, Anthony $u Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, Connecticut, USA

700    1_

$a Kiel, Aaron $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA

700    1_

$a Caimano, Melissa $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA $u Department of Medicine, UConn Health, Farmington, Connecticut, USA $u Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA

700    1_

$a Zhou, Yanjiao $u Department of Medicine, UConn Health, Farmington, Connecticut, USA $u The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA

700    1_

$a Lindgren, Jonathan $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA

700    1_

$a Krasulova, Kristyna $u Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic $1 https://orcid.org/0000000283036847

700    1_

$a Illes, Peter $u Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic $1 https://orcid.org/0000000339091491

700    1_

$a Dvořák, Zdeněk $u Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic $1 https://orcid.org/0000000239383585 $7 xx0118950

700    1_

$a Kortagere, Sandhya $u Department of Microbiology & Immunology, Drexel University, Philadelphia, Pennsylvania, USA $1 https://orcid.org/0000000235328669

700    1_

$a Kienesberger, Sabine $u Institute of Molecular Biosciences, University of Grazgrid.5110.5, BioTechMed-Graz, Graz, Austria $1 https://orcid.org/0000000331903678

700    1_

$a Cosic, Amar $u Institute of Molecular Biosciences, University of Grazgrid.5110.5, BioTechMed-Graz, Graz, Austria

700    1_

$a Pöltl, Lisa $u Institute of Molecular Biosciences, University of Grazgrid.5110.5, BioTechMed-Graz, Graz, Austria $1 https://orcid.org/0000000276283137

700    1_

$a Zechner, Ellen L $u Institute of Molecular Biosciences, University of Grazgrid.5110.5, BioTechMed-Graz, Graz, Austria $1 https://orcid.org/0000000320351898

700    1_

$a Ghosh, Subho $u Department of Medicine, Molecular Pharmacology and Genetics, Albert Einstein College of Medicine, Bronx, New York, USA

700    1_

$a Mani, Sridhar $u Department of Medicine, Molecular Pharmacology and Genetics, Albert Einstein College of Medicine, Bronx, New York, USA

700    1_

$a Radolf, Justin D $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA $u Department of Immunology, UConn Health, Farmington, Connecticut, USA $u Department of Medicine, UConn Health, Farmington, Connecticut, USA $u Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA $u Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA

700    1_

$a Matson, Adam P $u Department of Pediatrics, UConn Health, Farmington, Connecticut, USA $u Division of Neonatology, Connecticut Children's Medical Center, Hartford, Connecticut, USA $u Department of Immunology, UConn Health, Farmington, Connecticut, USA $1 https://orcid.org/0000000340800013

773    0_

$w MED00188129 $t mBio $x 2150-7511 $g Roč. 13, č. 1 (2022), s. e0375221

856    41

$u https://pubmed.ncbi.nlm.nih.gov/35073747 $y Pubmed

910    __

$a ABA008 $b sig $c sign $y p $z 0

990    __

$a 20230418 $b ABA008

991    __

$a 20230425171815 $b ABA008

999    __

$a ok $b bmc $g 1925189 $s 1191150

BAS    __

$a 3

BAS    __

$a PreBMC-MEDLINE

BMC    __

$a 2022 $b 13 $c 1 $d e0375221 $e 20220125 $i 2150-7511 $m mBio $n MBio $x MED00188129

LZP    __

$a Pubmed-20230418