scholarly journals Impact of Antibodies and Strain Polymorphisms on Cytomegalovirus Entry and Spread in Fibroblasts and Epithelial Cells

2017 ◽  
Vol 91 (13) ◽  
Author(s):  
Xiaohong Cui ◽  
Daniel C. Freed ◽  
Dai Wang ◽  
Ping Qiu ◽  
Fengsheng Li ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Viral Entry ◽  
Active Immunization ◽  
Cell Entry ◽  
Strain Specificity ◽  
Humoral Responses ◽  
Cmv Disease

ABSTRACT Cytomegalovirus (CMV) entry into fibroblasts differs from entry into epithelial cells. CMV also spreads cell to cell and can induce syncytia. To gain insights into these processes, 27 antibodies targeting epitopes in CMV virion glycoprotein complexes, including glycoprotein B (gB), gH/gL, and the pentamer, were evaluated for their effects on viral entry and spread. No antibodies inhibited CMV spread in fibroblasts, including those with potent neutralizing activity against fibroblast entry, while all antibodies that neutralized epithelial cell entry also inhibited spread in epithelial cells and a correlation existed between the potencies of these two activities. This suggests that exposure of virions to the cell culture medium is obligatory during spread in epithelial cells but not in fibroblasts. In fibroblasts, the formation of syncytiumlike structures was impaired not only by antibodies to gB or gH/gL but also by antibodies to the pentamer, suggesting a potential role for the pentamer in promoting fibroblast fusion. Four antibodies reacted with linear epitopes near the N terminus of gH, exhibited strain specificity, and neutralized both epithelial cell and fibroblast entry. Five other antibodies recognized conformational epitopes in gH/gL and neutralized both fibroblast and epithelial cell entry. That these antibodies were strain specific for neutralizing fibroblast but not epithelial cell entry suggests that polymorphisms external to certain gH/gL epitopes may influence antibody neutralization during fibroblast but not epithelial cell entry. These findings may have implications for elucidating the mechanisms of CMV entry, spread, and antibody evasion and may assist in determining which antibodies may be most efficacious following active immunization or passive administration. IMPORTANCE Cytomegalovirus (CMV) is a significant cause of birth defects among newborns infected in utero and morbidity and mortality in transplant and AIDS patients. Monoclonal antibodies and vaccines targeting humoral responses are under development for prophylactic or therapeutic use. The findings reported here (i) confirm that cell-to-cell spread of CMV is sensitive to antibody inhibition in epithelial cells but not fibroblasts, (ii) demonstrate that antibodies can restrict the formation in vitro of syncytiumlike structures that resemble syncytial cytomegalic cells that are associated with CMV disease in vivo, and (iii) reveal that neutralization of CMV by antibodies to certain epitopes in gH or gH/gL is both strain and cell type dependent and can be governed by polymorphisms in sequences external to the epitopes. These findings serve to elucidate the mechanisms of CMV entry, spread, and antibody evasion and may have important implications for the development of CMV vaccines and immunotherapeutics.

scholarly journals Human Cytomegalovirus Infection of Caco-2 Cells Occurs at the Basolateral Membrane and Is Differentiation State Dependent

1999 ◽  
Vol 73 (6) ◽  
pp. 4552-4560 ◽  
Author(s):  
Michael A. Jarvis ◽  
C. Edward Wang ◽  
Heather L. Meyers ◽  
Patricia P. Smith ◽  
Christopher L. Corless ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Human Cytomegalovirus ◽  
Viral Entry ◽  
Hcmv Infection ◽  
Cell Model ◽  
Basolateral Membrane ◽  
In Vitro Models

ABSTRACT Epithelial cells are known to be a major target for human cytomegalovirus (HCMV) infection; however, the analysis of virus-cell interactions has been difficult to approach due to the lack of in vitro models. In this study, we established a polarized epithelial cell model using a colon epithelial cell-derived cell line (Caco-2) that is susceptible to HCMV infection at early stages of cellular differentiation. Infection of polarized cells was restricted to the basolateral surface whereas virus was released apically, which was consistent with the apical and not basolateral surface localization of two essential viral glycoproteins, gB and gH. HCMV infection resulted in the development of a cytopathology characteristic of HCMV infection of colon epithelium in vivo, and infection did not spread from cell to cell. The inability of HCMV to infect Caco-2 cells at late stages of differentiation was due to a restriction at the level of viral entry and was consistent with the sequestration of a cellular receptor for HCMV. These observations provide the first evidence that restriction of HCMV replication in epithelial cells is due to a receptor-mediated phenomenon.

scholarly journals A Dual Role for Oncostatin M Signaling in the Differentiation and Death of Mammary Epithelial Cells in Vivo

2008 ◽  
Vol 22 (12) ◽  
pp. 2677-2688 ◽  
Author(s):  
Paul G. Tiffen ◽  
Nader Omidvar ◽  
Nuria Marquez-Almuina ◽  
Dawn Croston ◽  
Christine J. Watson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Oncostatin M ◽  
Specific Gene ◽  
Mammary Involution

Abstract Recent studies in breast cancer cell lines have shown that oncostatin M (OSM) not only inhibits proliferation but also promotes cell detachment and enhances cell motility. In this study, we have looked at the role of OSM signaling in nontransformed mouse mammary epithelial cells in vitro using the KIM-2 mammary epithelial cell line and in vivo using OSM receptor (OSMR)-deficient mice. OSM and its receptor were up-regulated approximately 2 d after the onset of postlactational mammary regression, in response to leukemia inhibitory factor (LIF)-induced signal transducer and activator of transcription-3 (STAT3). This resulted in sustained STAT3 activity, increased epithelial apoptosis, and enhanced clearance of epithelial structures during the remodeling phase of mammary involution. Concurrently, OSM signaling precipitated the dephosphorylation of STAT5 and repressed expression of the milk protein genes β-casein and whey acidic protein (WAP). Similarly, during pregnancy, OSM signaling suppressed β-casein and WAP gene expression. In vitro, OSM but not LIF persistently down-regulated phosphorylated (p)-STAT5, even in the continued presence of prolactin. OSM also promoted the expression of metalloproteinases MMP3, MMP12, and MMP14, which, in vitro, were responsible for OSM-specific apoptosis. Thus, the sequential activation of IL-6-related cytokines during mammary involution culminates in an OSM-dependent repression of epithelial-specific gene expression and the potentiation of epithelial cell extinction mediated, at least in part, by the reciprocal regulation of p-STAT5 and p-STAT3.

scholarly journals Identifying human and murine M cells in vitro

2019 ◽  
Vol 244 (7) ◽  
pp. 554-564 ◽  
Author(s):  
Ana Klisuric ◽  
Benjamin Thierry ◽  
Ludivine Delon ◽  
Clive A Prestidge ◽  
Rachel J Gibson
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
In Vitro Models ◽  
Oral Drug ◽  
M Cells ◽  
Cell Marker ◽  
M Cell ◽  
Follicle Associated Epithelium

M cells are an epithelial cell population found in the follicle-associated epithelium overlying gut-associated lymphoid tissues. They are specialized in the transcytosis of luminal antigens. Their transcytotic capacity and location in an immunocompetent environment has prompted the study of these cells as possible targets for oral drug delivery systems. Currently, the models most commonly used to study M cells are restricted to in vivo experiments conducted in mice, and in vitro studies conducted in models comprised either of primary epithelial cells or established cell lines of murine or human origin. In vitro models of the follicle-associated epithelium can be constructed in several ways. Small intestinal Lgr5+ stem cells can be cultured into a 3D organoid structure where M cells are induced with RANKL administration. Additionally, in vitro models containing an “M cell-like” population can be obtained through co-culturing intestinal epithelial cells with cells of lymphocytic origin to induce the M cell phenotype. The evaluation of the efficiency of the variations of these models and their relevance to the in vivo human system is hampered by the lack of a universal M cell marker. This issue has also hindered the advancement of M cell-specific targeting approaches aimed at improving the bioavailability of orally administered compounds. This critical review discusses the different approaches utilized in the literature to identify M cells, their efficiency, reliability and relevance, in the context of commonly used models of the follicle-associated epithelium. The outcome of this review is a clearly defined and universally recognized criteria for the assessment of the relevance of models of the follicle-associated models currently used. Impact statement The study of M cells, a specialized epithelial cell type found in the follicle-associated epithelium, is hampered by the lack of a universal M cell marker. As such, many studies lack reliable and universally recognized methods to identify M cells in their proposed models. As a result of this it is difficult to ascertain whether the effects observed are due to the presence of M cells or an unaccounted variable. The outcome of this review is the thorough evaluation of the many M cell markers that have been used in the literature thus far and a proposed criterion for the identification of M cells for future publications. This will hopefully lead to an improvement in the quality of future publications in this field.

scholarly journals Microfluidic approaches for epithelial cell layer culture and characterisation

The Analyst ◽  
2014 ◽  
Vol 139 (13) ◽  
pp. 3206-3218 ◽  
Author(s):  
Roland Thuenauer ◽  
Enrique Rodriguez-Boulan ◽  
Winfried Römer
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Layer ◽  
Microfluidic Biochips ◽  
Epithelial Cell Layer

Novelin vitromodels of epithelia in which thein vivomicroenvironment of epithelial cells is precisely reconstituted can be realised with microfluidic biochips.

scholarly journals Characterization of the Glycoprotein Stable Signal Peptide in Mediating Pichinde Virus Replication and Virulence

2016 ◽  
Vol 90 (22) ◽  
pp. 10390-10397 ◽  
Author(s):  
Junjie Shao ◽  
Xiaoying Liu ◽  
Hinh Ly ◽  
Yuying Liang
Keyword(s):  
Cell Culture ◽  
Membrane Fusion ◽  
Viral Entry ◽  
Reverse Genetics ◽  
Cell Entry ◽  
Pichinde Virus ◽  
Viral Virulence ◽  
Stable Signal

ABSTRACTArenaviruses can cause lethal hemorrhagic fevers in humans with few preventative and therapeutic measures. The arenaviral glycoprotein stable signal peptide (SSP) is unique among signal peptides in that it is an integral component of the mature glycoprotein complex (GPC) and plays important roles not only in GPC expression and processing but also in the membrane fusion process during viral entry. Using the Pichinde virus (PICV) reverse genetics system, we analyzed the effects of alanine substitutions at many conserved residues within the SSP on viral replication in cell culture and in a guinea pig infection model. Our data showed that the K33A, F49A, and C57A mutations abolished GPC-mediated cell entry and therefore could not allow for the generation of viable recombinant viruses, demonstrating that these residues are essential for the PICV life cycle. The G2A mutation caused a marked reduction of cell entry at the membrane fusion step, and while this mutant virus was viable, it was significantly attenuatedin vitroandin vivo. The N20A mutation also reduced membrane fusion activity and viral virulence in guinea pigs, but it did not significantly affect cell entry or viral growth in cell culture. Two other mutations (N37A and R55A) did not affect membrane fusion or viral growthin vitrobut significantly reduced viral virulencein vivo. Taken together, our data suggest that the GPC SSP plays an essential role in mediating viral entry and also contributes to viral virulencein vivo.IMPORTANCESeveral arenaviruses, such as Lassa fever virus, can cause severe and lethal hemorrhagic fever diseases with high mortality and morbidity, and no FDA-approved vaccines or therapies are currently available. Viral entry into cells is mediated by arenavirus GPC that consists of an SSP, the receptor-binding GP1, and transmembrane GP2 protein subunits. Using a reverse genetics system of a prototypic arenavirus, Pichinde virus (PICV), we have shown for the first time in the context of virus infections of cell culture and of guinea pigs that the SSP plays an essential role in mediating the membrane fusion step as well as in other yet-to-be-determined processes during viral infection. Our study provides important insights into the biological roles of GPC SSP and implicates it as a good target for the development of antivirals against deadly human arenavirus pathogens.

scholarly journals Rapid protein kinase D1 signaling promotes migration of intestinal epithelial cells

2012 ◽  
Vol 303 (3) ◽  
pp. G356-G366 ◽  
Author(s):  
Steven H. Young ◽  
Nora Rozengurt ◽  
James Sinnett-Smith ◽  
Enrique Rozengurt
Keyword(s):  
Protein Kinase ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Protein Kinase D1

We have examined the role of protein kinase D1 (PKD1) signaling in intestinal epithelial cell migration. Wounding monolayer cultures of intestinal epithelial cell line IEC-18 or IEC-6 induced rapid PKD1 activation in the cells immediately adjacent to the wound edge, as judged by immunofluorescence microscopy with an antibody that detects the phosphorylated state of PKD1 at Ser916, an autophosphorylation site. An increase in PKD1 phosphorylation at Ser916 was evident as early as 45 s after wounding, reached a maximum after 3 min, and persisted for ≥15 min. PKD1 autophosphorylation at Ser916 was prevented by the PKD family inhibitors kb NB 142-70 and CRT0066101. A kb NB 142-70-sensitive increase in PKD autophosphorylation was also elicited by wounding IEC-6 cells. Using in vitro kinase assays after PKD1 immunoprecipitation, we corroborated that wounding IEC-18 cells induced rapid PKD1 catalytic activation. Further results indicate that PKD1 signaling is required to promote migration of intestinal epithelial cells into the denuded area of the wound. Specifically, treatment with kb NB 142-70 or small interfering RNAs targeting PKD1 markedly reduced wound-induced migration in IEC-18 cells. To test whether PKD1 promotes migration of intestinal epithelial cells in vivo, we used transgenic mice that express elevated PKD1 protein in the small intestinal epithelium. Enterocyte migration was markedly increased in the PKD1 transgenic mice. These results demonstrate that PKD1 activation is one of the early events initiated by wounding a monolayer of intestinal epithelial cells and indicate that PKD1 signaling promotes the migration of these cells in vitro and in vivo.

scholarly journals Acidified Pepsin Promotes Laryngeal Precancerosis by Upregulating H+/K+-ATPase and Activating Mitophagy in Laryngeal Epithelial Cells

2020 ◽  
Author(s):  
Ke-Jia Cheng ◽  
Qiong Xu ◽  
Zhi-Mei Li ◽  
Shui-Hong Zhou ◽  
Yang-Yang Bao ◽  
...  
Keyword(s):  
Cell Growth ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Laryngopharyngeal Reflux ◽  
Upper Aerodigestive Tract ◽  
Promoting Effect ◽  
Growth And Survival ◽  
Laryngeal Mucosa

Abstract Background: Although laryngopharyngeal reflux (LPR) has been implicated in various upper aerodigestive tract and laryngeal diseases, the underlying mechanisms remain elusive. In this study, we investigated the role of gastric acidified pepsin in laryngeal precancerosis. Results: Acidified pepsin (pH=3) enhanced the growth and survival of mouse laryngeal epithelial cells in vitro and promoted laryngeal mucosal thickening and laryngeal epithelial cell growth in vivo. Furthermore, acidified pepsin promoted autophagy/mitophagy induction, accompanied by a significant decrease in mitochondrial membrane potential (MMP). Inhibition of autophagy by chloroquine abolished the ability of acidified pepsin to promote mitophagy and cell growth in laryngeal epithelial cells. Additionally, chloroquine promoted cell apoptosis and further reduced MMP in laryngeal epithelial cells treated with acidified pepsin. The expression levels of pepsin and H+/K+-ATPase α and β subunits in 31 human laryngeal mucosa specimens were 51.6%, 48.4%, and 48.4%, respectively. Importantly, the pepsin level was correlated with the H+/K+-ATPase β subunit level. H+/K+-ATPase upregulation in laryngeal epithelial cells in response to acidified pepsin was essential for the mitophagy-promoting effect of acidified pepsin. H+/K+-ATPase knockout or inhibition further reduced MMP in the presence of acidified pepsin. Conclusions: Our findings suggest that in an acidic environment, pepsin promotes laryngeal epithelial cell growth and survival by upregulating H+/K+-ATPase and activating mitophagy, potentially leading to laryngeal precancerosis.

Growth and differentiation of mouse tracheal epithelial cells: selection of a proliferative population

2002 ◽  
Vol 283 (6) ◽  
pp. L1315-L1321 ◽  
Author(s):  
Yingjian You ◽  
Edward J. Richer ◽  
Tao Huang ◽  
Steven L. Brody
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Airway Epithelial Cell ◽  
Airway Epithelial ◽  
Tracheal Epithelial Cells ◽  
Proliferation And Differentiation ◽  
Tracheal Epithelial

Highly regulated programs for airway epithelial cell proliferation and differentiation during development and repair are often disrupted in disease. These processes have been studied in mouse models; however, it is difficult to isolate and identify epithelial cell-specific responses in vivo. To investigate these processes in vitro, we characterized a model for primary culture of mouse tracheal epithelial cells. Small numbers of cells seeded at low density (7.5 × 104 cells/cm2) rapidly proliferated and became polarized. Subsequently, supplemented media and air-liquid interface conditions resulted in development of highly differentiated epithelia composed of ciliated and nonciliated cells with gene expression characteristic of native airways. Genetically altered or injured mouse tracheal epithelial cells also reflected in vivo patterns of airway epithelial cell gene expression. Passage of cells resulted in continued proliferation but limited differentiation after the first passage, suggesting that transit-amplifying cell populations were present but with independent programs for proliferation and differentiation. This approach provides a high-fidelity in vitro model for evaluation of gene regulation and expression in mouse airway epithelial cells.

scholarly journals Plasmolipin regulates basolateral-to-apical transcytosis of ICAM-1 and leukocyte adhesion in polarized hepatic epithelial cells

2022 ◽  
Vol 79 (1) ◽  
Author(s):  
Cristina Cacho-Navas ◽  
Natalia Reglero-Real ◽  
Natalia Colás-Algora ◽  
Susana Barroso ◽  
Gema de Rivas ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Intracellular Transport ◽  
Molecular Mechanisms ◽  
Apical Membrane ◽  
Membrane Domains ◽  
Adhesion Receptor ◽  
Epithelial Barriers

AbstractApical localization of Intercellular Adhesion Receptor (ICAM)-1 regulates the adhesion and guidance of leukocytes across polarized epithelial barriers. Here, we investigate the molecular mechanisms that determine ICAM-1 localization into apical membrane domains of polarized hepatic epithelial cells, and their effect on lymphocyte-hepatic epithelial cell interaction. We had previously shown that segregation of ICAM-1 into apical membrane domains, which form bile canaliculi and bile ducts in hepatic epithelial cells, requires basolateral-to-apical transcytosis. Searching for protein machinery potentially involved in ICAM-1 polarization we found that the SNARE-associated protein plasmolipin (PLLP) is expressed in the subapical compartment of hepatic epithelial cells in vitro and in vivo. BioID analysis of ICAM-1 revealed proximal interaction between this adhesion receptor and PLLP. ICAM-1 colocalized and interacted with PLLP during the transcytosis of the receptor. PLLP gene editing and silencing increased the basolateral localization and reduced the apical confinement of ICAM-1 without affecting apicobasal polarity of hepatic epithelial cells, indicating that ICAM-1 transcytosis is specifically impaired in the absence of PLLP. Importantly, PLLP depletion was sufficient to increase T-cell adhesion to hepatic epithelial cells. Such an increase depended on the epithelial cell polarity and ICAM-1 expression, showing that the epithelial transcytotic machinery regulates the adhesion of lymphocytes to polarized epithelial cells. Our findings strongly suggest that the polarized intracellular transport of adhesion receptors constitutes a new regulatory layer of the epithelial inflammatory response.

235. Activin C antagonises activin A in vitro and over-expression leads to prostate pathologies in vivo

2008 ◽  
Vol 20 (9) ◽  
pp. 35
Author(s):  
E. Gold ◽  
N. Jetly ◽  
S. Behuria ◽  
T. Woodruff ◽  
S. Hedwards ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Receptor Activation ◽  
Activin A ◽  
Ventral Prostate ◽  
Cell Hyperplasia ◽  
Signalling Molecules ◽  
Significant Difference

Activin A is a well characterised inhibitor of proliferation in most epithelial cells. The actions of activin A on cell growth are mediated through Smad-dependent pathways. Activin A is potent at low levels, therefore its synthesis and bioactivity must be tightly regulated. Follistatin binding or inhibin subunit heterodimerisation block access to the activin receptor and/or receptor activation. We postulate that another mechanism of regulating activin A bioactivity is through the activin-βC subunit. In order to test our hypothesis produced recombinant activin C and mice overexpressing activin-βC. Recombinant activin C abrogated activin A-induced growth inhibition in vitro and the mechanism of action was downregulation of activin A-induced Smad signalling molecules. In the prostate overexpression of activin-βC increased epithelial cell proliferation while there was no significant difference in apoptotic epithelial cells. This imbalance between proliferation and apoptosis led to a significant increase in ventral prostate weight, prostatic hypertrophy and epithelial cell hyperplasia. A significant decrease in nuclear localisation of Smad-2 was associated with activin-βC overexpression in the prostate which implies antagonism of activin signalling also occurs in vivo. This is the first study to provide evidence that activin-βC is an antagonist of activin A in vitro and in vivo and implicates a role for the activin-βC subunit in maintenance of tissue homeostasis in the prostate.

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