Global Gene Expression and the Role of Sigma Factors in Neisseria gonorrhoeae in Interactions with Epithelial Cells

ABSTRACT Like many bacterial pathogens, Neisseria gonorrhoeae must adapt to environmental changes in order to successfully colonize and proliferate in a new host. Modulation of gene expression in response to environmental signals is an efficient mechanism used by bacteria to achieve this goal. Using DNA microarrays and a tissue culture model for gonococcal infection, we examined global changes in gene expression in N. gonorrhoeae in response to adherence to host cells. Among those genes induced upon adherence to human epithelial cells in culture was rpoH, which encodes a homolog of the heat shock sigma factor, σ32 (RpoH), as well as genes of the RpoH regulon, groEL and groES. Attempts to construct an rpoH null mutant in N. gonorrhoeae were unsuccessful, suggesting that RpoH is essential for viability of N. gonorrhoeae. The extracytoplasmic sigma factor, RpoE (σE), while known to regulate rpoH in other bacteria, was found not to be necessary for the up-regulation of rpoH in gonococci upon adherence to host cells. To examine the role of RpoH in host cell interactions, an N. gonorrhoeae strain conditionally expressing rpoH was constructed. The results of our experiments showed that while induction of rpoH expression is not necessary for adherence of gonococci to epithelial cells, it is important for the subsequent invasion step, as gonococci depleted for rpoH invade cells two- to threefold less efficiently than a wild-type strain. Taken together, these results indicate that σ32, but not σE, is important for the response of gonococci in the initial steps of an infection.

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RpoH Mediates the Expression of Some, but Not All, Genes Induced in Neisseria gonorrhoeae Adherent to Epithelial Cells

Infection and Immunity ◽

10.1128/iai.74.5.2767-2776.2006 ◽

2006 ◽

Vol 74 (5) ◽

pp. 2767-2776 ◽

Cited By ~ 3

Author(s):

Ying Du ◽

Cindy Grove Arvidson

Keyword(s):

Epithelial Cells ◽

Neisseria Gonorrhoeae ◽

Host Cell ◽

Infection Process ◽

Host Cells ◽

Cell Contact ◽

Transmitted Infection ◽

New Host ◽

Sexually Transmitted ◽

Cell Induction

ABSTRACT Neisseria gonorrhoeae (gonococcus [GC]), is highly adapted to the human host, the only known reservoir for gonococcal infection. However, since it is sexually transmitted, infection of a new host likely requires a regulatory response on the part of the gonococcus to respond to this significant change in environment. We previously showed that adherence of gonococci to epithelial cells results in changes of gene expression in the bacteria that presumably prepare them for subsequent steps in the infection process. Expression of the heat shock sigma factor gene, rpoH, was shown to be important for the invasion step, as gonococci depleted for rpoH were reduced in their ability to invade epithelial cells. Here, we show that of the genes induced in adherent gonococci, two are part of the gonococcal RpoH regulon. When RpoH is depleted, expression of these genes is no longer induced by host cell contact, indicating that RpoH is mediating the host cell induction response of these genes. One RpoH-dependent gene, NGO0376, is shown to be important for invasion of epithelial cells, consistent with earlier observations that RpoH is necessary for this step of infection. Two genes, NGO1684 and NGO0340, while greatly induced by host cell contact, were found to be RpoH independent, indicating that more than one regulator is involved in the response to host cell contact. Furthermore, NGO0340, but not NGO1684, was shown to be important for both adherence and invasion of epithelial cells, suggesting a complex regulatory network in the response of gonococci to contact with host cells.

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Role of Lipooligosaccharide in Opa-Independent Invasion of Neisseria gonorrhoeae into Human Epithelial Cells

Journal of Experimental Medicine ◽

10.1084/jem.191.6.949 ◽

2000 ◽

Vol 191 (6) ◽

pp. 949-960 ◽

Cited By ~ 51

Author(s):

Wenxia Song ◽

Lang Ma ◽

Ruiwu Chen ◽

Daniel C. Stein

Keyword(s):

Epithelial Cells ◽

Neisseria Gonorrhoeae ◽

Outer Membrane ◽

Actin Filaments ◽

Direct Interaction ◽

Host Cells ◽

Bacterial Outer Membrane ◽

Isogenic Strains ◽

Adhesion And Invasion

Lipooligosaccharide (LOS) has been implicated in the adhesion and invasion of host epithelial cells. We examined the adhesive and invasive abilities of isogenic gonococcal opacity-associated outer membrane protein–negative, pilus-positive (Opa−Pil+) Neisseria gonorrhoeae strains expressing genetically defined LOS. Strain F62 (Opa−Pil+), expressing the lacto-N-neotetraose and the galNac-lacto-N-neotetraose LOS, and its isogenic derivative that expressed only the lacto-N-neotetraose LOS (F62ΔlgtD), adhered to, and invaded, to the same extent the human cervical epidermoid carcinoma cell line, ME180. While the adhesive abilities of Opa−Pil+ isogenic strains that express LOS molecules lacking the lacto-N-neotetraose structure were similar to that seen for F62, their invasive abilities were much lower than the strains expressing lacto-N-neotetraose. Fluorescence microscopy studies showed that the adherence of F62, but not the strains lacking lacto-N-neotetraose, induced the rearrangement of actin filaments under the adherent sites. Electron microscopy studies demonstrated that F62, but not the strains lacking lacto-N-neotetraose, formed extensive and intimate associations with epithelial cell membranes. Thus, in the absence of detectable Opa protein, the lacto-N-neotetraose LOS promotes gonococcal invasion into ME180 cells. The data also suggest that LOS is involved in the mobilization of actin filaments in host cells, and in the formation of a direct interaction between the bacterial outer membrane and the plasma membrane of ME180 cells.

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Time-resolved transcriptional profiling of Trichinella-infected murine myocytes helps to elucidate host–pathogen interactions in the muscle stage

Parasites & Vectors ◽

10.1186/s13071-021-04624-6 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Xiaoxiang Hu ◽

Xiaolei Liu ◽

Chen Li ◽

Yulu Zhang ◽

Chengyao Li ◽

...

Keyword(s):

Gene Expression ◽

Cell Biology ◽

Trichinella Spiralis ◽

Expression Patterns ◽

Muscle Cells ◽

Host Cells ◽

Initial Reaction ◽

Global Changes ◽

Mammalian Skeletal Muscle ◽

Time Resolved

Abstract Background Parasites of the genus Trichinella are the pathogenic agents of trichinellosis, which is a widespread and severe foodborne parasitic disease. Trichinella spiralis resides primarily in mammalian skeletal muscle cells. After invading the cells of the host organism, T. spiralis must elude or invalidate the host’s innate and adaptive immune responses to survive. It is necessary to characterize the pathogenesis of trichinellosis to help to prevent the occurrence and further progression of this disease. The aims of this study were to elucidate the mechanisms of nurse cell formation, pathogenesis and immune evasion of T. spiralis, to provide valuable information for further research investigating the basic cell biology of Trichinella-infected muscle cells and the interaction between T. spiralis and its host. Methods We performed transcriptome profiling by RNA sequencing to identify global changes at 1, 3, 7, 10 and 15 days post-infection (dpi) in gene expression in the diaphragm after the parasite entered and persisted within the murine myocytes; the mice were infected by intravenous injection of newborn larvae. Gene expression analysis was based on the alignment results. Differentially expressed genes (DEGs) were identified based on their expression levels in various samples, and functional annotation and enrichment analysis were performed. Results The most extensive and dynamic gene expression responses in host diaphragms were observed during early infection (1 dpi). The number of DEGs and genes annotated in the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology databases decreased significantly in the infected mice compared to the uninfected mice at 3 and 7 dpi, suddenly increased sharply at 10 dpi, and then decreased to a lower level at 15 dpi, similar to that observed at 3 and 7 dpi. The massive initial reaction of the murine muscle cells to Trichinella infection steadied in the later stages of infection, with little additional changes detected for the remaining duration of the studied process. Although there were hundreds of DEGs at each time point, only 11 genes were consistently up- or downregulated at all 5 time points. Conclusions The gene expression patterns identified in this study can be employed to characterize the coordinated response of T. spiralis-infected myocytes in a time-resolved manner. This comprehensive dataset presents a distinct and sensitive picture of the interaction between host and parasite during intracellular infection, which can help to elucidate how pathogens evade host defenses and coordinate the biological functions of host cells to survive in the mammalian environment.

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Role of Fosinopril and Valsartan on Klotho Gene Expression Induced by Angiotensin II in Rat Renal Tubular Epithelial Cells

Kidney & Blood Pressure Research ◽

10.1159/000316703 ◽

2010 ◽

Vol 33 (3) ◽

pp. 186-192 ◽

Cited By ~ 29

Author(s):

Q. Zhou ◽

S. Lin ◽

R. Tang ◽

P. Veeraragoo ◽

W. Peng ◽

...

Keyword(s):

Gene Expression ◽

Angiotensin Ii ◽

Epithelial Cells ◽

Tubular Epithelial Cells ◽

Renal Tubular Epithelial Cells ◽

Klotho Gene ◽

Renal Tubular

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OmpD but not OmpC is involved in adherence ofSalmonella entericaserovar Typhimurium to human cells

Canadian Journal of Microbiology ◽

10.1139/w04-056 ◽

2004 ◽

Vol 50 (9) ◽

pp. 719-727 ◽

Cited By ~ 17

Author(s):

Bochiwe Hara-Kaonga ◽

Thomas G Pistole

Keyword(s):

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Human Cells ◽

Host Cells ◽

Intestinal Epithelial ◽

Wild Type ◽

Human Macrophages ◽

Significant Difference ◽

Serovar Typhimurium

Conflicting reports exist regarding the role of porins OmpC and OmpD in infections due to Salmonella enterica serovar Typhimurium. This study investigated the role of these porins in bacterial adherence to human macrophages and intestinal epithelial cells. ompC and ompD mutant strains were created by transposon mutagenesis using P22-mediated transduction of Tn10 and Tn5 insertions, respectively, into wild-type strain 14028. Fluorescein-labeled wild-type and mutant bacteria were incubated with host cells at various bacteria to cell ratios for 1 h at 37 °C and analyzed by flow cytometry. The mean fluorescence intensity of cells with associated wild-type and mutant bacteria was used to estimate the number of bacteria bound per host cell. Adherence was also measured by fluorescence microscopy. Neither assay showed a significant difference in binding of the ompC mutant and wild-type strains to the human cells. In contrast, the ompD mutant exhibited lowered binding to both cell types. Our findings suggest that OmpD but not OmpC is involved in the recognition of Salmonella serovar Typhimurium by human macrophages and intestinal epithelial cells.Key words: Salmonella, adherence, porins, intestinal epithelial cells, macrophage.

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Inactivation of Genes Encoding MutL and MutS Proteins Influences Adhesion and Biofilm Formation by Neisseria gonorrhoeae

Microorganisms ◽

10.3390/microorganisms7120647 ◽

2019 ◽

Vol 7 (12) ◽

pp. 647 ◽

Cited By ~ 1

Author(s):

Jagoda Płaczkiewicz ◽

Monika Adamczyk-Popławska ◽

Robert Lasek ◽

Pawel Bącal ◽

Agnieszka Kwiatek

Keyword(s):

Epithelial Cells ◽

Neisseria Gonorrhoeae ◽

Biofilm Formation ◽

Dna Microarrays ◽

Wild Type ◽

Human Genes ◽

Genes Encoding ◽

Differential Gene ◽

Bacterial Genes ◽

Muts Gene

Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem. This bacterium possesses MutL and MutS DNA repair proteins encoded by mutL and mutS genes, whose inactivation causes a mutator phenotype. We have demonstrated the differential gene expression in N. gonorrhoeae mutL and mutS mutants using DNA microarrays. A subset of differentially expressed genes encodes proteins that can influence adhesion and biofilm formation. Compared to the wild-type strain, N. gonorrhoeae mutL and mutS mutants formed denser biofilms with increased biofilm-associated biomass on the abiotic surface. The N. gonorrhoeae mutS::km, but not the mutL mutant, was also more adherent and invasive to human epithelial cells. Further, during infection of epithelial cells with N. gonorrhoeae mutS::km, the expression of some bacterial genes encoding proteins that can influence gonococcal adhesion was changed compared with their expression in cells infected with the wild-type gonococcus, as well as of human genes’ encoding receptors utilized by N. gonorrhoeae (CD46, CEACAM 1, HSPG 2). Thus, deficiency in the mutS gene resulting in increased mutation frequency in singular organisms can be beneficial in populations because these mutants can be a source of features linked to microbial fitness.

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Roles of Elongator Dependent tRNA Modification Pathways in Neurodegeneration and Cancer

Genes ◽

10.3390/genes10010019 ◽

2018 ◽

Vol 10 (1) ◽

pp. 19 ◽

Cited By ~ 18

Author(s):

Harmen Hawer ◽

Alexander Hammermeister ◽

Keerthiraju Ravichandran ◽

Sebastian Glatt ◽

Raffael Schaffrath ◽

...

Keyword(s):

Gene Expression ◽

Human Disease ◽

Messenger Rna ◽

Environmental Changes ◽

Mrna Translation ◽

Regulatory Control ◽

Trna Modification ◽

Positive Role ◽

Trna Modifications

Transfer RNA (tRNA) is subject to a multitude of posttranscriptional modifications which can profoundly impact its functionality as the essential adaptor molecule in messenger RNA (mRNA) translation. Therefore, dynamic regulation of tRNA modification in response to environmental changes can tune the efficiency of gene expression in concert with the emerging epitranscriptomic mRNA regulators. Several of the tRNA modifications are required to prevent human diseases and are particularly important for proper development and generation of neurons. In addition to the positive role of different tRNA modifications in prevention of neurodegeneration, certain cancer types upregulate tRNA modification genes to sustain cancer cell gene expression and metastasis. Multiple associations of defects in genes encoding subunits of the tRNA modifier complex Elongator with human disease highlight the importance of proper anticodon wobble uridine modifications (xm5U34) for health. Elongator functionality requires communication with accessory proteins and dynamic phosphorylation, providing regulatory control of its function. Here, we summarized recent insights into molecular functions of the complex and the role of Elongator dependent tRNA modification in human disease.

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Pseudomonas aeruginosa Infection of Airway Epithelial Cells Modulates Expression of Kruppel-Like Factors 2 and 6 via RsmA-Mediated Regulation of Type III Exoenzymes S and Y

Infection and Immunity ◽

10.1128/iai.00489-06 ◽

2006 ◽

Vol 74 (10) ◽

pp. 5893-5902 ◽

Cited By ~ 26

Author(s):

Eoin P. O'Grady ◽

Heidi Mulcahy ◽

Julie O'Callaghan ◽

Claire Adams ◽

Fergal O'Gara

Keyword(s):

Gene Expression ◽

Pseudomonas Aeruginosa ◽

Transcription Factors ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Effector Proteins ◽

Host Cells ◽

Airway Epithelial ◽

Type Iii ◽

Enhanced Expression

ABSTRACT Pseudomonas aeruginosa is an important opportunistic pathogen which is capable of causing both acute and chronic infections in immunocompromised patients. Successful adaptation of the bacterium to its host environment relies on the ability of the organism to tightly regulate gene expression. RsmA, a small RNA-binding protein, controls the expression of a large number of virulence-related genes in P. aeruginosa, including those encoding the type III secretion system and associated effector proteins, with important consequences for epithelial cell morphology and cytotoxicity. In order to examine the influence of RsmA-regulated functions in the pathogen on gene expression in the host, we compared global expression profiles of airway epithelial cells in response to infection with P. aeruginosa PAO1 and an rsmA mutant. The RsmA-dependent response of host cells was characterized by significant changes in the global transcriptional pattern, including the increased expression of two Kruppel-like factors, KLF2 and KLF6. This increased expression was mediated by specific type III effector proteins. ExoS was required for the enhanced expression of KLF2, whereas both ExoS and ExoY were required for the enhanced expression of KLF6. Neither ExoT nor ExoU influenced the expression of the transcription factors. Additionally, the increased gene expression of KLF2 and KLF6 was associated with ExoS-mediated cytotoxicity. Therefore, this study identifies for the first time the human transcription factors KLF2 and KLF6 as targets of the P. aeruginosa type III exoenzymes S and Y, with potential importance in host cell death.

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