scholarly journals Role of the Campylobacter jejuni Cj1461 DNA Methyltransferase in Regulating Virulence Characteristics

2008 ◽  
Vol 190 (19) ◽  
pp. 6524-6529 ◽  
Author(s):  
Joo-Sung Kim ◽  
Jiaqi Li ◽  
If H. A. Barnes ◽  
David A. Baltzegar ◽  
Mohanasundari Pajaniappan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Mutant Strain ◽  
Campylobacter Jejuni ◽  
Dna Methyltransferase ◽  
Wild Type ◽  
Less Invasive ◽  
Human Epithelial Cells ◽  
Methyltransferase Gene

ABSTRACT Mutation of the cj1461 predicted methyltransferase gene reduced the motility of Campylobacter jejuni 81-176. Electron microscopy revealed that the mutant strain had flagella but with aberrant structure. The Δcj1461 mutant was sevenfold more adherent to but 50-fold less invasive of INT-407 human epithelial cells than the wild type.

The Campylobacter jejuni general glycosylation system is important for attachment to human epithelial cells and in the colonization of chicks

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1957-1964 ◽  
Author(s):  
A. V. Karlyshev ◽  
P. Everest ◽  
D. Linton ◽  
S. Cawthraw ◽  
D. G. Newell ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Campylobacter Jejuni ◽  
Host Cells ◽  
High Similarity ◽  
Human Epithelial Cells

It has recently been shown that the enteropathogen Campylobacter jejuni has an N-linked general protein glycosylation pathway (Pgl) that modifies many of the organism's proteins. To determine the role of the N-linked general glycosylation in C jejuni, the authors studied the pglH gene, which shows high similarity to a family of sugar transferases. pglH mutants were constructed in strains 81116 and 11168H. Both mutants were shown to be deficient in their ability to glycosylate a number of C. jejuni proteins, but their lipooligosaccharide and capsule were unaffected. The pglH mutants had significantly reduced ability to adhere to and invade human epithelial Caco-2 cells. Additionally, the 81116 pglH mutant was severely affected in its ability to colonize chicks. These results suggest that glycosylation is important for the attachment of C. jejuni to human and chicken host cells and imply a role for glycoproteins in the pathogenesis of C. jejuni.

scholarly journals Expression of lysophosphatidic acid receptor 5 is necessary for the regulation of intestinal Na+/H+ exchanger 3 by lysophosphatidic acid in vivo

2018 ◽  
Vol 315 (4) ◽  
pp. G433-G442 ◽  
Author(s):  
Kayte A. Jenkin ◽  
Peijian He ◽  
C. Chris Yun
Keyword(s):  
Epithelial Cells ◽  
Lysophosphatidic Acid ◽  
Direct Evidence ◽  
Intestinal Epithelial Cells ◽  
Regulatory Role ◽  
Intestinal Epithelial ◽  
Fluid Absorption ◽  
Wild Type

Lysophosphatidic acid (LPA) is a bioactive lipid molecule, which regulates a broad range of pathophysiological processes. Recent studies have demonstrated that LPA modulates electrolyte flux in the intestine, and its potential as an antidiarrheal agent has been suggested. Of six LPA receptors, LPA5 is highly expressed in the intestine. Recent studies by our group have demonstrated activation of Na+/H+ exchanger 3 (NHE3) by LPA5. However, much of what has been elucidated was achieved using colonic cell lines that were transfected to express LPA5. In the current study, we engineered a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC, and investigated the role of LPA5 in NHE3 regulation and fluid absorption in vivo. The intestine of Lpar5ΔIEC mice appeared morphologically normal, and the stool frequency and fecal water content were unchanged compared with wild-type mice. Basal rates of NHE3 activity and fluid absorption and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5. NHE3 activation involves trafficking of NHE3 from the terminal web to microvilli, and this mobilization of NHE3 by LPA was abolished in Lpar5ΔIEC mice. Dysregulation of NHE3 was specific to LPA, and insulin and cholera toxin were able to stimulate and inhibit NHE3, respectively, in both wild-type and Lpar5ΔIEC mice. The current study for the first time demonstrates the necessity of LPA5 in LPA-mediated stimulation of NHE3 in vivo. NEW & NOTEWORTHY This study is the first to assess the role of LPA5 in NHE3 regulation and fluid absorption in vivo using a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC. Basal rates of NHE3 activity and fluid absorption, and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5.

scholarly journals Porphyromonas gingivalis Impairs Oral Epithelial Barrier through Targeting GRHL2

2019 ◽  
Vol 98 (10) ◽  
pp. 1150-1158 ◽  
Author(s):  
W. Chen ◽  
A. Alshaikh ◽  
S. Kim ◽  
J. Kim ◽  
C. Chun ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Oral Mucosa ◽  
Porphyromonas Gingivalis ◽  
Oral Bacteria ◽  
Conditional Knockout ◽  
Epithelial Barrier ◽  
Wild Type ◽  
Oral Epithelial ◽  
Junction Proteins

Oral mucosa provides the first line of defense against a diverse array of environmental and microbial irritants by forming the barrier of epithelial cells interconnected by multiprotein tight junctions (TJ), adherens junctions, desmosomes, and gap junction complexes. Grainyhead-like 2 (GRHL2), an epithelial-specific transcription factor, may play a role in the formation of the mucosal epithelial barrier, as it regulates the expression of the junction proteins. The current study investigated the role of GRHL2 in the Porphyromonas gingivalis ( Pg)–induced impairment of epithelial barrier functions. Exposure of human oral keratinocytes (HOK-16B and OKF6 cells) to Pg or Pg-derived lipopolysaccharides ( Pg LPSs) led to rapid loss of endogenous GRHL2 and the junction proteins (e.g., zonula occludens, E-cadherin, claudins, and occludin). GRHL2 directly regulated the expression levels of the junction proteins and the epithelial permeability for small molecules (e.g., dextrans and Pg bacteria). To explore the functional role of GRHL2 in oral mucosal barrier, we used a Grhl2 conditional knockout (KO) mouse model, which allows for epithelial tissue-specific Grhl2 KO in an inducible manner. Grhl2 KO impaired the expression of the junction proteins at the junctional epithelium and increased the alveolar bone loss in the ligature-induced periodontitis model. Fluorescence in situ hybridization revealed increased epithelial penetration of oral bacteria in Grhl2 KO mice compared with the wild-type mice. Also, blood loadings of oral bacteria (e.g., Bacteroides, Bacillus, Firmicutes, β- proteobacteria, and Spirochetes) were significantly elevated in Grhl2 KO mice compared to the wild-type littermates. These data indicate that Pg bacteria may enhance paracellular penetration through oral mucosa in part by targeting the expression of GRHL2 in the oral epithelial cells, which then impairs the epithelial barrier by inhibition of junction protein expression, resulting in increased alveolar tissue destruction and systemic bacteremia.

scholarly journals Cryptococcus neoformans Evades Pulmonary Immunity by Modulating Xylose Precursor Transport

2020 ◽  
Vol 88 (8) ◽  
Author(s):  
Lucy X. Li ◽  
Camaron R. Hole ◽  
Javier Rangel-Moreno ◽  
Shabaana A. Khader ◽  
Tamara L. Doering
Keyword(s):  
Cryptococcus Neoformans ◽  
Mutant Strain ◽  
Fungal Pathogen ◽  
Wild Type ◽  
Content Type ◽  
Helper Cell Type ◽  
Lymphoid Structures ◽  
Type Infection

ABSTRACT Cryptococcus neoformans is a fungal pathogen that kills almost 200,000 people each year and is distinguished by abundant and unique surface glycan structures that are rich in xylose. A mutant strain of C. neoformans that cannot transport xylose precursors into the secretory compartment is severely attenuated in virulence in mice yet surprisingly is not cleared. We found that this strain failed to induce the nonprotective T helper cell type 2 (Th2) responses characteristic of wild-type infection, instead promoting sustained interleukin 12p40 (IL-12p40) induction and increased IL-17A (IL-17) production. It also stimulated dendritic cells to release high levels of proinflammatory cytokines, a behavior we linked to xylose expression. We further discovered that inducible bronchus-associated lymphoid tissue (iBALT) forms in response to infection with either wild-type cryptococci or the mutant strain with reduced surface xylose; although iBALT formation is slowed in the latter case, the tissue is better organized. Finally, our temporal studies suggest that lymphoid structures in the lung restrict the spread of mutant fungi for at least 18 weeks after infection, which is in contrast to ineffective control of the pathogen after infection with wild-type cells. These studies demonstrate the role of xylose in modulation of host response to a fungal pathogen and show that cryptococcal infection triggers iBALT formation.

scholarly journals Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

Reproduction ◽  
2012 ◽  
Vol 143 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Sayaka Koyanagi ◽  
Hiroko Hamasaki ◽  
Satoshi Sekiguchi ◽  
Kenshiro Hara ◽  
Yoshiyuki Ishii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Proteomic Analysis ◽  
Ubiquitin Proteasome System ◽  
Underlying Mechanism ◽  
Wild Type ◽  
Transmission Electron ◽  
Ubiquitin Proteasome

Maternal proteins are rapidly degraded by the ubiquitin–proteasome system during oocyte maturation in mice. Ubiquitin C-terminal hydrolase L1 (UCHL1) is highly and specifically expressed in mouse ova and is involved in the polyspermy block. However, the role of UCHL1 in the underlying mechanism of polyspermy block is poorly understood. To address this issue, we performed a comprehensive proteomic analysis to identify maternal proteins that were relevant to the role of UCHL1 in mouse ova using UCHL1-deficientgad. Furthermore, we assessed morphological features ingadmouse ova using transmission electron microscopy. NACHT, LRR, and PYD domain-containing (NALP) family proteins and endoplasmic reticulum (ER) chaperones were identified by proteomic analysis. We also found that the ‘maternal antigen that embryos require’ (NLRP5 (MATER)) protein level increased significantly ingadmouse ova compared with that in wild-type mice. In an ultrastructural study,gadmouse ova contained less ER in the cortex than in wild-type mice. These results provide new insights into the role of UCHL1 in the mechanism of polyspermy block in mouse ova.

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

2004 ◽  
Vol 50 (9) ◽  
pp. 719-727 ◽  
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.

Catalase activity in Campylobacter jejuni: comparison of a wild-type strain with an aerotolerant variant

1990 ◽  
Vol 36 (6) ◽  
pp. 449-451 ◽  
Author(s):  
Pamela A. Vercellone ◽  
Robert M. Smibert ◽  
Noel R. Krieg
Keyword(s):  
Campylobacter Jejuni ◽  
Catalase Activity ◽  
Specific Activity ◽  
Wild Type ◽  
Oxygen Tolerance ◽  
Variant Strain ◽  
Cultural Conditions ◽  
Cell Extracts ◽  
Bactericidal Effects

A comparison of Campylobacter jejuni VPI strain H840 (ATCC 29428), which can grow at O2 levels up to 15%, with variant strain MC711-01 (which can grown at O2 levels up to 21–26%) indicated that the specific activity of catalase in crude cell extracts was higher in the variant by a factor of 1.6 to 2.5, depending on cultural conditions. Smaller differences occurred with superoxide dismutase activity, while peroxidase activities were invariably lower in the variant strain. The variant strain was much more resistant than the wild type to the bactericidal effects of H2O2. The results suggest that catalase activity might be one of the factors associated with the greater tolerance of O2 by the variant strain. However, both strains became more susceptible to H2O2 when cultures were initially grown at 6% O2 and then shifted to 21% O2; thus the role of catalase in the oxygen tolerance of C. jejuni is probably minor. Key words: Campylobacter jejuni, catalase, oxygen tolerance.

scholarly journals The β-tail domain (βTD) regulates physiologic ligand binding to integrin CD11b/CD18

Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3513-3520 ◽  
Author(s):  
Vineet Gupta ◽  
Annette Gylling ◽  
José Luis Alonso ◽  
Takashi Sugimori ◽  
Petre Ianakiev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ligand Binding ◽  
Conformational Changes ◽  
Divalent Cations ◽  
Contact Region ◽  
Allosteric Modulator ◽  
Tail Domain ◽  
Wild Type ◽  
High Affinity

Abstract Crystallographic and electron microscopy studies revealed genuflexed (bent) integrins in both unliganded (inactive) and physiologic ligandbound (active) states, suggesting that local conformational changes are sufficient for activation. Herein we have explored the role of local changes in the contact region between the membrane-proximal β-tail domain (βTD) and the ligand-binding βA domain of the bent conformation in regulating interaction of integrin CD11b/CD18 (αMβ2) with its physiologic ligand iC3b. We replaced the βTD CD loop residues D658GMD of the CD18 (β2) subunit with the equivalent D672SSG of the β3 subunit, with AGAA or with NGTD, expressed the respective heterodimeric receptors either transiently in epithelial HEK293T cells or stably in leukocytes (K562), and measured their ability to bind iC3b and to conformation-sensitive mAbs. In the presence of the physiologic divalent cations Ca2+ plus Mg2+ (at 1 mM each), the modified integrins showed increased (in HEK293) or constitutive (in K562) binding to iC3b compared with wild-type receptors. K562 expressing the βTD-modified integrins bound in Ca2+Mg2+ to the βA-directed high-affinity reporter mAb 24 but not to mAb KIM127, a reporter of the genu-straightened state. These data identify a role for the membrane proximal βTD as an allosteric modulator of integrin activation.

scholarly journals Role of DNA methylation in expression control of the IKZF3-GSDMA region in human epithelial cells

PLoS ONE ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. e0172707 ◽  
Author(s):  
Sanny Moussette ◽  
Abeer Al Tuwaijri ◽  
Hamid-Reza Kohan-Ghadr ◽  
Samar Elzein ◽  
Raquel Farias ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Epithelial Cells ◽  
Expression Control ◽  
Human Epithelial Cells
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