scholarly journals Host Cell Contact-Induced Transcription of the Type IV Fimbria Gene Cluster of Actinobacillus pleuropneumoniae

2004 ◽  
Vol 72 (2) ◽  
pp. 691-700 ◽  
Author(s):  
Bouke K. H. L. Boekema ◽  
Jos P. M. Van Putten ◽  
Norbert Stockhofe-Zurwieden ◽  
Hilde E. Smith
Keyword(s):  
Epithelial Cells ◽  
Host Cell ◽  
Gene Cluster ◽  
Promoter Activity ◽  
Actinobacillus Pleuropneumoniae ◽  
Lung Epithelial Cells ◽  
Cell Contact ◽  
Variable Expression ◽  
Type Iv

ABSTRACT Type IV pili (Tfp) of gram-negative species share many characteristics, including a common architecture and conserved biogenesis pathway. Much less is known about the regulation of Tfp expression in response to changing environmental conditions. We investigated the diversity of Tfp regulatory systems by searching for the molecular basis of the reported variable expression of the Tfp gene cluster of the pathogen Actinobacillus pleuropneumoniae. Despite the presence of an intact Tfp gene cluster consisting of four genes, apfABCD, no Tfp were formed under standard growth conditions. Sequence analysis of the predicted major subunit protein ApfA showed an atypical alanine residue at position −1 from the prepilin peptidase cleavage site in 42 strains. This alanine deviates from the consensus glycine at this position in Tfp from other species. Yet, cloning of the apfABCD genes under a constitutive promoter in A. pleuropneumoniae resulted in pilin and Tfp assembly. Tfp promoter-luxAB reporter gene fusions demonstrated that the Tfp promoter was intact but tightly regulated. Promoter activity varied with bacterial growth phase and was detected only when bacteria were grown in chemically defined medium. Infection experiments with cultured epithelial cells demonstrated that Tfp promoter activity was upregulated upon adherence of the pathogen to primary cultures of lung epithelial cells. Nonadherent bacteria in the culture supernatant exhibited virtually no promoter activity. A similar upregulation of Tfp promoter activity was observed in vivo during experimental infection of pigs. The host cell contact-induced and in vivo-upregulated Tfp promoter activity in A. pleuropneumoniae adds a new dimension to the diversity of Tfp regulation.

scholarly journals In Vivo and In Vitro Analysis of Factor Binding Sites in Jaagsiekte Sheep Retrovirus Long Terminal Repeat Enhancer Sequences: Roles of HNF-3, NF-I, and C/EBP for Activity in Lung Epithelial Cells

2006 ◽  
Vol 80 (1) ◽  
pp. 332-341 ◽  
Author(s):  
Kathleen McGee-Estrada ◽  
Hung Fan
Keyword(s):  
Epithelial Cells ◽  
Long Terminal Repeat ◽  
Binding Site ◽  
Terminal Repeat ◽  
Lung Epithelial Cells ◽  
Type Ii ◽  
Jaagsiekte Sheep Retrovirus ◽  
Efficient System ◽  
Lung Epithelial

ABSTRACT Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma, a contagious lung cancer of sheep that arises from type II pneumocytes and Clara cells of the lung epithelium. Studies of the tropism of this virus have been hindered by the lack of an efficient system for viral replication in tissue culture. To map regulatory regions important for transcriptional activation, an in vivo footprinting method that couples dimethyl sulfate treatment and ligation-mediated PCR was performed in murine type II pneumocyte-derived MLE-15 cells infected with a chimeric Moloney murine leukemia virus driven by the JSRV enhancers (ΔMo+JS Mo-MuLV). In vivo footprints were found in the JSRV enhancers in two regions previously shown to be important for JSRV long terminal repeat (LTR) activity: a binding site for the lung-specific transcription factor HNF-3β and an E-box element in the distal enhancer adjacent to an NF-κB-like binding site. In addition, in vivo footprints were detected in two downstream motifs likely to bind C/EBP and NF-I. Mutational analysis of a JSRV LTR reporter construct (pJS21luc) revealed that the C/EBP binding site is critical for LTR activity, while the putative NF-I binding element is less important; elimination of these sites resulted in 70% and 40% drops in LTR activity, respectively. Electrophoretic mobility shift assays using nuclear extracts from MLE-15 murine Clara cell-derived mtCC1-2 cells with probes corresponding to the NF-I or C/EBP sites revealed several complexes. Antiserum directed against NF-IA, C/EBPα, or C/EBPβ supershifted the corresponding protein-DNA complexes, indicating that these isoforms, which are also important for the expression of several cellular lung-specific genes, may be important for JSRV expression in lung epithelial cells.

scholarly journals EphB6 Regulates TFEB-Lysosomal Pathway and Survival of Disseminated Indolent Breast Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1079
Author(s):  
Manuela Zangrossi ◽  
Patrizia Romani ◽  
Probir Chakravarty ◽  
Colin D.H. Ratcliffe ◽  
Steven Hooper ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Epithelial Cells ◽  
Cancer Cells ◽  
Lung Epithelial Cells ◽  
Late Relapse ◽  
Alveolar Type ◽  
Type I ◽  
Extrinsic Factors ◽  
Lung Epithelial

Late relapse of disseminated cancer cells is a common feature of breast and prostate tumors. Several intrinsic and extrinsic factors have been shown to affect quiescence and reawakening of disseminated dormant cancer cells (DDCCs); however, the signals and processes sustaining the survival of DDCCs in a foreign environment are still poorly understood. We have recently shown that crosstalk with lung epithelial cells promotes survival of DDCCs of estrogen receptor-positive (ER+) breast tumors. By using a lung organotypic system and in vivo dissemination assays, here we show that the TFEB-lysosomal axis is activated in DDCCs and that it is modulated by the pro-survival ephrin receptor EphB6. TFEB lysosomal direct targets are enriched in DDCCs in vivo and correlate with relapse in ER+ breast cancer patients. Direct coculture of DDCCs with alveolar type I-like lung epithelial cells and dissemination in the lung drive lysosomal accumulation and EphB6 induction. EphB6 contributes to survival, TFEB transcriptional activity, and lysosome formation in DDCCs in vitro and in vivo. Furthermore, signaling from EphB6 promotes the proliferation of surrounding lung parenchymal cells in vivo. Our data provide evidence that EphB6 is a key factor in the crosstalk between disseminated dormant cancer cells and the lung parenchyma and that the TFEB-lysosomal pathway plays an important role in the persistence of DDCCs.

scholarly journals Physical and Functional Interactions between Homeodomain NKX2.1 and Winged Helix/Forkhead FOXA1 in Lung Epithelial Cells

2007 ◽  
Vol 27 (6) ◽  
pp. 2155-2165 ◽  
Author(s):  
Parviz Minoo ◽  
Lingyan Hu ◽  
Yiming Xing ◽  
Nian Ling Zhu ◽  
Hongyan Chen ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Epithelial Cells ◽  
Target Genes ◽  
Lung Epithelial Cells ◽  
Mobility Shift ◽  
Independent Manner ◽  
Winged Helix ◽  
Gradient Distribution ◽  
Functional Interactions

ABSTRACT NKX2.1 is a homeodomain transcription factor that controls development of the brain, lung, and thyroid. In the lung, Nkx2.1 is expressed in a proximo-distal gradient and activates specific genes in phenotypically distinct epithelial cells located along this axis. The mechanisms by which NKX2.1 controls its target genes may involve interactions with other transcription factors. We examined whether NKX2.1 interacts with members of the winged-helix/forkhead family of FOXA transcription factors to regulate two spatially and cell type-specific genes, SpC and Ccsp. The results show that NKX2.1 interacts physically and functionally with FOXA1. The nature of the interaction is inhibitory and occurs through the NKX2.1 homeodomain in a DNA-independent manner. On SpC, which lacks a FOXA1 binding site, FOXA1 attenuates NKX2.1-dependent transcription. Inhibition of FOXA1 by small interfering RNA increased SpC mRNA, demonstrating the in vivo relevance of this finding. In contrast, FOXA1 and NKX2.1 additively activate transcription from Ccsp, which includes both NKX2.1 and FOXA1 binding sites. In electrophoretic mobility shift assays, the GST-FOXA1 fusion protein interferes with the formation of NKX2.1 transcriptional complexes by potentially masking the latter's homeodomain DNA binding function. These findings suggest a novel mode of selective gene regulation by proximo-distal gradient distribution of and functional interactions between forkhead and homeodomain transcription factors.

scholarly journals Influenza A Virus Infection Induces Apical Redistribution of Na+, K+-ATPase in Lung Epithelial Cells In Vitro and In Vivo

2019 ◽  
Vol 61 (3) ◽  
pp. 395-398
Author(s):  
Christin Peteranderl ◽  
Irina Kuznetsova ◽  
Jessica Schulze ◽  
Martin Hardt ◽  
Emilia Lecuona ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Influenza A ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Influenza A Virus Infection

scholarly journals IL-13 Mediates In Vivo IL-9 Activities on Lung Epithelial Cells but Not on Hematopoietic Cells

2007 ◽  
Vol 178 (5) ◽  
pp. 3244-3251 ◽  
Author(s):  
Valérie Steenwinckel ◽  
Jamila Louahed ◽  
Ciriana Orabona ◽  
François Huaux ◽  
Guy Warnier ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Hematopoietic Cells ◽  
Lung Epithelial Cells ◽  
Lung Epithelial

Differentiation of Lung Epithelial Cells from Murine Embryonic Stem Cells with in Vivo Implantation

2013 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Christine Finck ◽  
Blair Roszell ◽  
Todd Jensen ◽  
Ariel Seaton ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Epithelial Cells ◽  
Embryonic Stem ◽  
Lung Epithelial Cells ◽  
Murine Embryonic Stem Cells ◽  
Lung Epithelial

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

2006 ◽  
Vol 74 (5) ◽  
pp. 2767-2776 ◽  
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.

scholarly journals Efficient Translocation of EspC into Epithelial Cells Depends on Enteropathogenic Escherichia coli and Host Cell Contact

2006 ◽  
Vol 74 (4) ◽  
pp. 2293-2303 ◽  
Author(s):  
Jorge E. Vidal ◽  
Fernando Navarro-García
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Host Cell ◽  
Cytopathic Effect ◽  
Cell Interaction ◽  
Cell Contact ◽  
Internalization Mechanism ◽  
Cell Cytosol ◽  
Cytoskeletal Disruption

ABSTRACT EspC is an autotransporter protein secreted by enteropathogenic Escherichia coli (EPEC). The pathogenic role of EspC in EPEC infection is unknown. We have shown that the purified EspC produces enterotoxicity and cytotoxicity; for the latter effect, EspC must be internalized. However, the internalization mechanism is unknown. Here we show that azithromycin (an inhibitor of pinocytosis), but not drugs affecting caveole-, clathrin-, or receptor-mediated endocytosis, inhibited purified EspC internalization and cytoskeletal disruption, suggesting that purified EspC is internalized by pinocytosis. Furthermore, unlike in cholera toxin, we were unable to detect a receptor on epithelial cells by pretreatment at 4°C. Upon EspC entry, it is delivered directly into the cell cytosol, as shown by the fact that drugs that inhibit intracellular trafficking had no effect on cytoskeletal disruption. All these data suggest that purified EspC internalization is not a physiological internalization mechanism; hence, we explored EspC internalization during the infection of epithelial cells by EPEC. Like other EPEC virulence factors, EspC secretion is stimulated by EPEC when it is grown in cell culture medium and enhanced by the presence of epithelial cells. Physiologically secreted EspC was efficiently internalized during EPEC and host cell interaction. Additionally, the lack of EspC internalization caused by using an isogenic mutant prevented the cytopathic effect caused by EPEC. These data suggest that EPEC uses an efficient mechanism to internalize milieu-secreted EspC into epithelial cells; once inside the cells, EspC is able to induce the cytopathic effect caused by EPEC.

scholarly journals Type IV Secretion Machinery Promotes Ton-Independent Intracellular Survival of Neisseria gonorrhoeae within Cervical Epithelial Cells

2010 ◽  
Vol 78 (6) ◽  
pp. 2429-2437 ◽  
Author(s):  
Tracey A. Zola ◽  
Heather R. Strange ◽  
Nadia M. Dominguez ◽  
Joseph P. Dillard ◽  
Cynthia N. Cornelissen
Keyword(s):  
Epithelial Cells ◽  
Neisseria Gonorrhoeae ◽  
Host Cell ◽  
Iron Acquisition ◽  
Intracellular Survival ◽  
Type Iv Secretion ◽  
Open Reading Frames ◽  
Cell Infection ◽  
Type Iv ◽  
Cervical Epithelial Cells

ABSTRACT Survival of Neisseria gonorrhoeae within host epithelial cells is expected to be important in the pathogenesis of gonococcal disease. We previously demonstrated that strain FA1090 derives iron from a host cell in a process that requires the Ton complex and a putative TonB-dependent transporter, TdfF. FA1090, however, lacks the gonococcal genetic island (GGI) that is present in the majority of strains. The GGI in strain MS11 has been partially characterized, and it encodes a type IV secretion system (T4SS) involved in DNA release. In this study we investigated the role of iron acquisition and GGI-encoded gene products in gonococcal survival within cervical epithelial cells. We demonstrated that intracellular survival of MS11 was dependent on acquisition of iron from the host cell, but unlike the findings for FA1090, expression of the Ton complex was not required. Survival was not dependent on a putative TonB-like protein encoded in the GGI but instead was directly linked to T4SS structural components in a manner independent of the ability to release or internalize DNA. These data suggest that expression of selected GGI-encoded open reading frames confers an advantage during cervical cell infection. This study provides the first link between expression of the T4SS apparatus and intracellular survival of gonococci.

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