Roles of TroA and TroR in Metalloregulated Growth and Gene Expression in Treponema denticola

ABSTRACT The availability of divalent metal cations required as cofactors for microbial metabolism is severely limited in the host environment. Bacteria have evolved highly regulated uptake systems to maintain essential metal homeostasis to meet cellular demands while preventing toxicity. The Tro operon (troABCDR), present in all sequenced Treponema spp., is a member of a highly conserved family of ATP-binding cassette transporters involved in metal cation uptake whose expression is controlled by TroR, a DtxR-like cation-responsive regulatory protein. Transcription of troA responds to divalent manganese and iron (T. denticola) or manganese and zinc (T. pallidum), and metal-dependent TroR binding to the troA promoter represses troA transcription. We report here the construction and complementation of defined T. denticola ΔtroR and ΔtroA strains to characterize (i) the role of TroA in metal-dependent T. denticola growth and (ii) the role of TroR in T. denticola gene expression. We show that TroA expression is required for T. denticola growth under iron- and manganese-limited conditions. Furthermore, TroR is required for the transcriptional regulation of troA in response to iron or manganese, and deletion of troR results in significant differential expression of more than 800 T. denticola genes in addition to troA. These results suggest that (i) TroA-mediated cation uptake is important in metal homeostasis in vitro and may be important for Treponema survival in the host environment and (ii) the absence of TroR results in significant dysregulation of nearly one-third of the T. denticola genome. These effects may be direct (as with troA) or indirect due to dysregulation of metal homeostasis. IMPORTANCE Treponema denticola is one of numerous host-associated spirochetes, a group including commensals, pathobionts, and at least one frank pathogen. While most T. denticola research concerns its role in periodontitis, its relative tractability for growth and genetic manipulation make it a useful model for studying Treponema physiology, metabolism, and host-microbe interactions. Metal micronutrient acquisition and homeostasis are highly regulated both in microbial cells and by host innate defense mechanisms that severely limit metal cation bioavailability. Here, we characterized the T. denticola troABCDR operon, the role of TroA-mediated iron and manganese uptake in growth, and the effects of TroR on global gene expression. This study contributes to our understanding of the mechanisms involved in cellular metal homeostasis required for survival in the host environment.

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Characterization of Host Responses duringPseudomonas aeruginosaAcute Infection in the Lungs and Blood and after Treatment with the Synthetic Immunomodulatory Peptide IDR-1002

Infection and Immunity ◽

10.1128/iai.00661-18 ◽

2018 ◽

Vol 87 (1) ◽

Cited By ~ 8

Author(s):

Kelli Wuerth ◽

Amy H. Y. Lee ◽

Reza Falsafi ◽

Erin E. Gill ◽

Robert E. W. Hancock

Keyword(s):

Gene Expression ◽

Bacterial Resistance ◽

Lymphocyte Activation ◽

Lavage Fluid ◽

Innate Immune ◽

Microbial Infection ◽

Content Type ◽

Innate Defense ◽

Lung Infections

ABSTRACTPseudomonas aeruginosais an opportunistic pathogen that causes nosocomial pneumonia and infects patients with cystic fibrosis.P. aeruginosalung infections are difficult to treat due to bacterial resistance to antibiotics, and strains with multidrug resistance are becoming more prevalent. Here, we examined the use of a small host defense peptide, innate defense regulator 1002 (IDR-1002), in an acuteP. aeruginosalung infectionin vivo. IDR-1002 significantly reduced the bacterial burden in bronchoalveolar lavage fluid (BALF), as well as MCP-1 in BALF and serum, KC in serum, and interleukin 6 (IL-6) in BALF. Transcriptome sequencing (RNA-Seq) was conducted on lungs and whole blood, and the effects ofP. aeruginosa, IDR-1002, and the combination ofP. aeruginosaand IDR-1002 were evaluated. Differential gene expression analysis showed thatP. aeruginosaincreased multiple inflammatory and innate immune pathways, as well as affected hemostasis, matrix metalloproteinases, collagen biosynthesis, and various metabolism pathways in the lungs and/or blood. Infected mice treated with IDR-1002 had significant changes in gene expression compared to untreated infected mice, with fewer differentially expressed genes associated with the inflammatory and innate immune responses to microbial infection, and treatment also affected morphogenesis, certain metabolic pathways, and lymphocyte activation. Overall, these results showed that IDR-1002 was effective in treatingP. aeruginosaacute lung infections and associated inflammation.

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Cyclic Diguanylate Regulates Virulence Factor Genes via Multiple Riboswitches inClostridium difficile

mSphere ◽

10.1128/msphere.00423-18 ◽

2018 ◽

Vol 3 (5) ◽

Cited By ~ 11

Author(s):

Robert W. McKee ◽

Carissa K. Harvest ◽

Rita Tamayo

Keyword(s):

Gene Expression ◽

Clostridium Difficile ◽

Biofilm Formation ◽

Toxin Production ◽

Intestinal Colonization ◽

Cyclic Diguanylate ◽

Signaling Molecule ◽

Content Type ◽

Surface Motility

ABSTRACTThe intracellular signaling molecule cyclic diguanylate (c-di-GMP) regulates many processes in bacteria, with a central role in controlling the switch between motile and nonmotile lifestyles. Recent work has shown that inClostridium difficile(also calledClostridioides difficile), c-di-GMP regulates swimming and surface motility, biofilm formation, toxin production, and intestinal colonization. In this study, we determined the transcriptional regulon of c-di-GMP inC. difficile,employing overexpression of a diguanylate cyclase gene to artificially manipulate intracellular c-di-GMP. Consistent with prior work, c-di-GMP regulated the expression of genes involved in swimming and surface motility. c-di-GMP also affected the expression of multiple genes encoding cell envelope proteins, several of which affected biofilm formationin vitro. A substantial proportion of the c-di-GMP regulon appears to be controlled either directly or indirectly via riboswitches. We confirmed the functionality of 11 c-di-GMP riboswitches, demonstrating their effects on downstream gene expression independent of the upstream promoters. The class I riboswitches uniformly functioned as “off” switches in response to c-di-GMP, while class II riboswitches acted as “on” switches. Transcriptional analyses of genes 3′ of c-di-GMP riboswitches over a broad range of c-di-GMP levels showed that relatively modest changes in c-di-GMP levels are capable of altering gene transcription, with concomitant effects on microbial behavior. This work expands the known c-di-GMP signaling network inC. difficileand emphasizes the role of the riboswitches in controlling known and putative virulence factors inC. difficile.IMPORTANCEInClostridium difficile, the signaling molecule c-di-GMP regulates multiple processes affecting its ability to cause disease, including swimming and surface motility, biofilm formation, toxin production, and intestinal colonization. In this study, we used RNA-seq to define the transcriptional regulon of c-di-GMP inC. difficile. Many new targets of c-di-GMP regulation were identified, including multiple putative colonization factors. Transcriptional analyses revealed a prominent role for riboswitches in c-di-GMP signaling. Only a subset of the 16 previously predicted c-di-GMP riboswitches were functionalin vivoand displayed potential variability in their response kinetics to c-di-GMP. This work underscores the importance of studying c-di-GMP riboswitches in a relevant biological context and highlights the role of the riboswitches in controlling gene expression inC. difficile.

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CsrA (BB0184) Is Not Involved in Activation of the RpoN-RpoS Regulatory Pathway in Borrelia burgdorferi

Infection and Immunity ◽

10.1128/iai.01555-13 ◽

2014 ◽

Vol 82 (4) ◽

pp. 1511-1522 ◽

Cited By ~ 10

Author(s):

Zhiming Ouyang ◽

Jianli Zhou ◽

Michael V. Norgard

Keyword(s):

Gene Expression ◽

Borrelia Burgdorferi ◽

Animal Studies ◽

Expression System ◽

Regulatory Pathway ◽

Content Type ◽

Mouse Tissues ◽

Differential Gene ◽

Carbon Storage Regulator

ABSTRACTBorrelia burgdorferiencodes a homologue of the bacterial carbon storage regulator A (CsrA). Recently, it was reported that CsrA contributes toB. burgdorferiinfectivity and is required for the activation of the central RpoN-RpoS regulatory pathway. However, many questions concerning the function of CsrA inB. burgdorferigene regulation remain unanswered. In particular, there are conflicting reports concerning the molecular details of how CsrA may modulaterpoSexpression and, thus, how CsrA may influence the RpoN-RpoS pathway inB. burgdorferi. To address these key discrepancies, we examined the role of CsrA in differential gene expression in the Lyme disease spirochete. Upon engineering an induciblecsrAexpression system inB. burgdorferi, controlled hyperexpression of CsrA in a merodiploid strain did not significantly alter the protein and transcript levels ofbosR,rpoS, and RpoS-dependent genes (such asospCanddbpA). In addition, we constructed isogeniccsrAmutants in two widely used infectiousB. burgdorferistrains. When expression ofbosR,rpoS,ospC, anddbpAwas compared between thecsrAmutants and their wild-type counterparts, no detectable differences were observed. Finally, animal studies indicated that thecsrAmutants remained infectious for and virulent in mice. Analyses ofB. burgdorferigene expression in mouse tissues showed comparable levels ofrpoStranscripts by thecsrAmutants and the parental strains. Taken together, these results constitute compelling evidence that CsrA is not involved in activation of the RpoN-RpoS pathway and is dispensable for mammalian infectious processes carried out byB. burgdorferi.

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TheTreponema denticolaPAS Domain-Containing Histidine Kinase Hpk2 Is a Heme Binding Sensor of Oxygen Levels

Journal of Bacteriology ◽

10.1128/jb.00116-18 ◽

2018 ◽

Vol 200 (18) ◽

Cited By ~ 1

Author(s):

Juni Sarkar ◽

Daniel P. Miller ◽

Lee D. Oliver ◽

Richard T. Marconi

Keyword(s):

Microbial Community ◽

Periodontal Disease ◽

Histidine Kinase ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Treponema Denticola ◽

Pas Domain ◽

Adaptive Responses ◽

Content Type

ABSTRACTPeriodontal disease (PD) results from a shift in the composition of the microbial community of the subgingival crevice. As the bacterial population transitions from Gram-positive bacteria to predominantly Gram-negative anaerobes and spirochetes, dramatic changes occur in the physiological and immunological environment at diseased sites.Treponema denticolathrives in periodontal pockets, indicating that it has a unique ability to adapt to changing environmental conditions. Hpk2 (tde1970), a Per-Arnt-Sim motif (PAS) domain-containing histidine kinase (HK), is part of theT. denticolaHpk2-Rrp2 (tde1969) two-component regulatory (TCR) system. This TCR system is growth phase regulated and has been postulated to play a key role in adaptive responses. In this study, we employ predictive structural analyses and site-directed mutagenesis to investigate the functional role of specific amino acid residues located within the Hpk2 PAS domain. Specific substitutions impacted autophosphorylation (AP), phosphotransfer (PT), oligomerization, and hemin binding. The AP, PT, hemin binding, and oligomerization potential of some mutated Hpk2 proteins differed under aerobic versus anaerobic reaction conditions. The data presented here suggest that the regulatory activity of Hpk2 is linked to diatomic gas levels. In a broader sense, this study highlights the importance of studying proteins produced by anaerobes under conditions that approximate the environment in which they thrive.IMPORTANCEPeriodontal disease affects nearly 60% of the global adult population. Its costs to individuals, and to society as a whole, are enormous. As periodontal disease develops, there is a shift in the composition of the oral microbial community. The bacteria that become dominant are able to cause significant damage to the tissues that support the teeth, leading to tooth loss.Treponema denticolais one of the keystone pathogens associated with periodontal disease. An earlier study demonstrated that the Hpk2 and Rrp2 proteins play an important role in adaptive responses. Here, we explore the role of specific Hpk2 amino acids in environmental sensing and function, using structural analyses and site-directed mutagenesis.

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Transcription of the Subtilase Cytotoxin Gene subAB1 in Shiga Toxin-Producing Escherichia coli Is Dependent on hfq and hns

Applied and Environmental Microbiology ◽

10.1128/aem.01281-19 ◽

2019 ◽

Vol 85 (20) ◽

Cited By ~ 2

Author(s):

Laura Heinisch ◽

Katharina Zoric ◽

Maike Krause ◽

Herbert Schmidt

Keyword(s):

Gene Expression ◽

Escherichia Coli ◽

Shiga Toxin ◽

Promoter Activity ◽

Deletion Mutants ◽

Content Type ◽

E Coli ◽

Intensive Investigation ◽

Subtilase Cytotoxin

ABSTRACT Certain foodborne Shiga toxin-producing Escherichia coli (STEC) strains carry genes encoding the subtilase cytotoxin (SubAB). Although the mode of action of SubAB is under intensive investigation, information about the regulation of subAB gene expression is currently not available. In this study, we investigated the regulation of the chromosomal subAB1 gene in laboratory E. coli strain DH5α and STEC O113:H21 strain TS18/08 using a luciferase reporter gene assay. Special emphasis was given to the role of the global regulatory protein genes hfq and hns in subAB1 promoter activity. Subsequently, quantitative real-time PCR was performed to analyze the expression of Shiga toxin 2a (Stx2a), SubAB1, and cytolethal distending toxin V (Cdt-V) genes in STEC strain TS18/08 and its isogenic hfq and hns deletion mutants. The deletion of hfq led to a significant increase of up to 2-fold in subAB1 expression, especially in the late growth phase, in both strains. However, deletion of hns showed different effects on the promoter activity during the early and late exponential growth phases in both strains. Furthermore, upregulation of stx2a and cdt-V was demonstrated in hfq and hns deletion mutants in TS18/08. These data showed that the expression of subAB1, stx2a, and cdt-V is integrated in the regulatory network of global regulators Hfq and H-NS in Escherichia coli. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) strains are responsible for outbreaks of foodborne diseases, such as hemorrhagic colitis and the hemolytic uremic syndrome. The pathogenicity of those strains can be attributed to, among other factors, the production of toxins. Recently, the subtilase cytotoxin was detected in locus of enterocyte effacement (LEE)-negative STEC, and it was confirmed that it contributes to the cytotoxicity of those STEC strains. Although the mode of action of SubAB1 is under intensive investigation, the regulation of gene expression is currently not known. The global regulatory proteins H-NS and Hfq have impact on many cellular processes and have been described to regulate virulence factors as well. Here, we investigate the role of hns and hfq in expression of subAB1 as well as stx2a and cdt-V in an E. coli laboratory strain as well as in wild-type STEC strain TS18/08.

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Interplay of a Ligand Sensor and an Enzyme in Controlling Expression of the Saccharomyces cerevisiae GAL Genes

Eukaryotic Cell ◽

10.1128/ec.05294-11 ◽

2011 ◽

Vol 11 (3) ◽

pp. 334-342 ◽

Cited By ~ 17

Author(s):

Dariusz Abramczyk ◽

Stacey Holden ◽

Christopher J. Page ◽

Richard J. Reece

Keyword(s):

Gene Expression ◽

Saccharomyces Cerevisiae ◽

Transcriptional Control ◽

Transcriptional Response ◽

Content Type ◽

Considerable Debate ◽

Active Transcription ◽

Gal Genes ◽

The Subject

ABSTRACT The regulation of the Saccharomyces cerevisiae GAL genes in response to galactose as a source of carbon has served as a paradigm for eukaryotic transcriptional control over the last 50 years. Three proteins—a transcriptional activator (Gal4p), an inhibitor (Gal80p), and a ligand sensor (Gal3p)—control the switch between inert and active gene expression. The molecular mechanism by which the recognition of galactose within the cell is converted into a transcriptional response has been the subject of considerable debate. In this study, using a novel and powerful method of localizing active transcription factors within the nuclei of cells, we show that a short-lived complex between Gal4p, Gal80p, and Gal3p occurs soon after the addition of galactose to cells to activate GAL gene expression. Gal3p is subsequently replaced in this complex by Gal1p, and a Gal4p-Gal80p-Gal1p complex is responsible for the continued expression of the GAL genes. The transient role of the ligand sensor indicates that current models for the induction and continued expression of the yeast GAL genes need to be reevaluated.

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Regulation by ToxR-Like Proteins Converges onvttRBExpression To Control Type 3 Secretion System-Dependent Caco2-BBE Cytotoxicity in Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.00130-16 ◽

2016 ◽

Vol 198 (11) ◽

pp. 1675-1682 ◽

Cited By ~ 6

Author(s):

Kelly A. Miller ◽

Madeline K. Sofia ◽

Jacob W. A. Weaver ◽

Christopher H. Seward ◽

Michelle Dziejman

Keyword(s):

Gene Expression ◽

Cell Death ◽

Vibrio Cholerae ◽

Secretion System ◽

Content Type ◽

Transcriptional Regulatory ◽

Type 3 Secretion System ◽

Type 3

ABSTRACTGenes carried on the type 3 secretion system (T3SS) pathogenicity island ofVibrio choleraenon-O1/non-O139 serogroup strain AM-19226 must be precisely regulated in order for bacteria to cause disease. Previously reported results showed that both T3SS function and the presence of bile are required to cause Caco2-BBE cell cytotoxicity during coculture with strain AM-19226. We therefore investigated additional parameters affectingin vitrocell death, including bacterial load and the role of three transmembrane transcriptional regulatory proteins, VttRA, VttRB, and ToxR. VttRAand VttRBare encoded on the horizontally acquired T3SS genomic island, whereas ToxR is encoded on the ancestral chromosome. While strains carrying deletions in any one of the three transcriptional regulatory genes are unable to cause eukaryotic cell death, the results of complementation studies point to a hierarchy of regulatory control that converges onvttRBexpression. The data suggest both that ToxR and VttRAact upstream of VttRBand that modifying the level of eithervttRAorvttRBexpression can strongly influence T3SS gene expression. We therefore propose a model whereby T3SS activity and, hence,in vitrocytotoxicity are ultimately regulated byvttRBexpression.IMPORTANCEIn contrast to O1 and O139 serogroupV. choleraestrains that cause cholera using two main virulence factors (toxin-coregulated pilus [TCP] and cholera toxin [CT]), O39 serogroup strain AM-19226 uses a type 3 secretion system as its principal virulence mechanism. Although the regulatory network governing TCP and CT expression is well understood, the factors influencing T3SS-associated virulence are not. Using anin vitromammalian cell model to investigate the role of three ToxR-like transmembrane transcriptional activators in causing T3SS-dependent cytotoxicity, we found that expression levels and a hierarchical organization were important for promoting T3SS gene expression. Furthermore, our results suggest that horizontally acquired, ToxR-like proteins act in concert with the ancestral ToxR protein to orchestrate T3SS-mediated pathogenicity.

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iac Gene Expression in the Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter soli LF7

Applied and Environmental Microbiology ◽

10.1128/aem.01057-18 ◽

2018 ◽

Vol 84 (19) ◽

Cited By ~ 6

Author(s):

Isaac V. Greenhut ◽

Beryl L. Slezak ◽

Johan H. J. Leveau

Keyword(s):

Gene Expression ◽

Acetic Acid ◽

Promoter Region ◽

Deletion Mutant ◽

Plant Hormone ◽

Major Facilitator Superfamily ◽

Soil Bacterium ◽

Content Type ◽

Indole 3 Acetic Acid

ABSTRACT We show for soil bacterium Enterobacter soli LF7 that the possession of an indole-3-acetic acid catabolic (iac) gene cluster is causatively linked to the ability to utilize the plant hormone indole-3-acetic acid (IAA) as a carbon and energy source. Genome-wide transcriptional profiling by mRNA sequencing revealed that these iac genes, chromosomally arranged as iacHABICDEFG and coding for the transformation of IAA to catechol, were the most highly induced (>29-fold) among the relatively few (<1%) differentially expressed genes in response to IAA. Also highly induced and immediately downstream of the iac cluster were genes for a major facilitator superfamily protein (mfs) and enzymes of the β-ketoadipate pathway (pcaIJD-catBCA), which channels catechol into central metabolism. This entire iacHABICDEFG-mfs-pcaIJD-catBCA gene set was constitutively expressed in an iacR deletion mutant, confirming the role of iacR, annotated as coding for a MarR-type regulator and located upstream of iacH, as a repressor of iac gene expression. In E. soli LF7 carrying the DNA region upstream of iacH fused to a promoterless gfp gene, green fluorescence accumulated in response to IAA at concentrations as low as 1.6 μM. The iacH promoter region also responded to chlorinated IAA, but not other aromatics tested, indicating a narrow substrate specificity. In an iacR deletion mutant, gfp expression from the iacH promoter region was constitutive, consistent with the predicted role of iacR as a repressor. A deletion analysis revealed putative −35/−10 promoter sequences upstream of iacH, as well as a possible binding site for the IacR repressor. IMPORTANCE Bacterial iac genes code for the enzymatic conversion of the plant hormone indole-3-acetic acid (IAA) to catechol. Here, we demonstrate that the iac genes of soil bacterium Enterobacter soli LF7 enable growth on IAA by coarrangement and coexpression with a set of pca and cat genes that code for complete conversion of catechol to central metabolites. This work contributes in a number of novel and significant ways to our understanding of iac gene biology in bacteria from (non-)plant environments. More specifically, we show that LF7's response to IAA involves derepression of the MarR-type transcriptional regulator IacR, which is quite fast (less than 25 min upon IAA exposure), highly specific (only in response to IAA and chlorinated IAA, and with few genes other than iac, cat, and pca induced), relatively sensitive (low micromolar range), and seemingly tailored to exploit IAA as a source of carbon and energy.

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Privatization of Biofilm Matrix in Structurally Heterogeneous Biofilms

mSystems ◽

10.1128/msystems.00425-20 ◽

2020 ◽

Vol 5 (4) ◽

Author(s):

Simon B. Otto ◽

Marivic Martin ◽

Daniel Schäfer ◽

Raimo Hartmann ◽

Knut Drescher ◽

...

Keyword(s):

Gene Expression ◽

Shear Stress ◽

Content Type ◽

Matrix Gene ◽

Starting Point ◽

The Matrix ◽

Matrix Components ◽

Biofilm Development ◽

The Impact

ABSTRACT The self-produced biofilm provides beneficial protection for the enclosed cells, but the costly production of matrix components makes producer cells susceptible to cheating by nonproducing individuals. Despite detrimental effects of nonproducers, biofilms can be heterogeneous, with isogenic nonproducers being a natural consequence of phenotypic differentiation processes. For instance, in Bacillus subtilis biofilm cells differ in production of the two major matrix components, the amyloid fiber protein TasA and exopolysaccharides (EPS), demonstrating different expression levels of corresponding matrix genes. This raises questions regarding matrix gene expression dynamics during biofilm development and the impact of phenotypic nonproducers on biofilm robustness. Here, we show that biofilms are structurally heterogeneous and can be separated into strongly and weakly associated clusters. We reveal that spatiotemporal changes in structural heterogeneity correlate with matrix gene expression, with TasA playing a key role in biofilm integrity and timing of development. We show that the matrix remains partially privatized by the producer subpopulation, where cells tightly stick together even when exposed to shear stress. Our results support previous findings on the existence of “weak points” in seemingly robust biofilms as well as on the key role of linkage proteins in biofilm formation. Furthermore, we provide a starting point for investigating the privatization of common goods within isogenic populations. IMPORTANCE Biofilms are communities of bacteria protected by a self-produced extracellular matrix. The detrimental effects of nonproducing individuals on biofilm development raise questions about the dynamics between community members, especially when isogenic nonproducers exist within wild-type populations. We asked ourselves whether phenotypic nonproducers impact biofilm robustness, and where and when this heterogeneity of matrix gene expression occurs. Based on our results, we propose that the matrix remains partly privatized by the producing subpopulation, since producing cells stick together when exposed to shear stress. The important role of linkage proteins in robustness and development of the structurally heterogeneous biofilm provides an entry into studying the privatization of common goods within isogenic populations.

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New Role of Nod Proteins in Regulation of Intestinal Goblet Cell Response in the Context of Innate Host Defense in an Enteric Parasite Infection

Infection and Immunity ◽

10.1128/iai.01187-15 ◽

2015 ◽

Vol 84 (1) ◽

pp. 275-285 ◽

Cited By ~ 15

Author(s):

Huaqing Wang ◽

Janice J. Kim ◽

Emmanuel Denou ◽

Amanda Gallagher ◽

David J. Thornton ◽

...

Keyword(s):

Goblet Cell ◽

Cell Response ◽

Periodic Acid ◽

Goblet Cells ◽

Parasitic Infections ◽

Double Knockout ◽

Trichuris Muris ◽

Content Type ◽

Innate Defense

Mucins secreted by intestinal goblet cells are considered an important component of innate defense in a number of enteric infections, including many parasitic infections, but also likely provide protection against the gut microbiota. Nod proteins are intracellular receptors that play key roles in innate immune response and inflammation. Here, we investigated the role of Nod proteins in regulation of intestinal goblet cell response in naive mice and mice infected with the enteric parasiteTrichuris muris. We observed significantly fewer periodic acid-Schiff (PAS)-stained intestinal goblet cells and less mucin (Muc2) in Nod1 and Nod2 double-knockout (Nod DKO) mice afterT. murisinfection than in wild-type (WT) mice. Expulsion of parasites from the intestine was significantly delayed in Nod DKO mice. Treatment of naive WT mice with Nod1 and Nod2 agonists simultaneously increased numbers of PAS-stained goblet cells and Muc2-expressing cells, whereas treatment with Nod1 or Nod2 separately had no significant effect. Stimulation of mucin-secreting LS174T cells with Nod1 and Nod2 agonists upregulated core 3 β1,3-N-acetylglucosaminyltransferase (C3GnT; an important enzyme in mucin synthesis) and MUC2. We also observed lower numbers of PAS-stained goblet cells and less Muc2 in germfree mice. Treatment with Nod1 and Nod2 agonists enhanced the production of PAS-stained goblet cells and Muc2 in germfree mice. These data provide novel information on the role of Nod proteins in goblet cell response and Muc2 production in relation to intestinal innate defense.

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