scholarly journals Cytotoxic effects of manganese oxide nanoparticles in combination with microbial components on intestinal epithelial cells

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 975
Author(s):  
Jorrell Fredericks ◽  
Sujata Senapati ◽  
Michael J. Wannemuehler

Background: Manganese oxide has been shown to cause toxicity and is associated with occupational-related disease (e.g., welders). With the goal to improve several biomedical areas, manganese oxide nanoparticles (MnO NP) are being considered for use in drug delivery and magnetic resonance imaging (MRI) to obtain high resolution anatomical images of tumors and gastrointestinal (GI) inflammation. Regardless of whether it is intentional or unintentional ingestion, the GI tract has been shown to be the primary route of entry for metal nanoparticles including MnO NP. However, studies assessing toxicity of MnO NP for intestinal epithelial cells (IECs) are virtually nonexistent. Methods: Given the proximity to the GI lumen, assessing the effects of nanoparticles on IECs in the presence of bacterial components presents a more holistic model of exposure. Therefore, we examined the effects of MnO NP alone and MnO NP in combination with Escherichia coli LF82 bacterial lysate on selected functions of MODE-K cells, a murine intestinal epithelial cell line. Data were analyzed using one-way ANOVA. Differences with p < 0.05 were considered significant. Results: Results showed MnO NP plus E. coli LF82 lysate added to MODE-K cells severely inhibited monolayer scratch wound healing, enhanced the secretion of interleukin 6 (IL-6), and induced mitochondrial dysfunction. Conclusions: Overall, our findings show that toxicity of MnO NP deleteriously affected MODE-K cells and demonstrated the necessity to integrate other environmental factors, such as microbial components and/or inflammatory cytokines, into studies assessing effects of nanoparticles on mucosal epithelia.

1997 ◽  
Vol 272 (4) ◽  
pp. G879-G884 ◽  
Author(s):  
P. E. Wischmeyer ◽  
M. W. Musch ◽  
M. B. Madonna ◽  
R. Thisted ◽  
E. B. Chang

Glutamine (Gln) protects gut mucosa against injury and promotes mucosal healing. Because the induction of heat shock proteins (HSP) protects cells under conditions of stress, we determined whether Gln conferred protection against stress in an intestinal epithelial cell line through HSP induction. Gln added to IEC-18 cells induces an increase in HSP70, a concentration-dependent effect also seen with mRNA. Two forms of injury, lethal heat (49 degrees C) and oxidant, were used, and viability was determined by 51Cr release. Gln-treated cells were significantly more resistant to injury. Treatment with 6-diazo-5-oxo-L-norleucine (DON), a nonmetabolizable analog of Gln, induced HSP70 and protected cells from injury, but less than Gln. These findings suggest that the effects of Gln on HSP70 induction and cellular protection are mediated by metabolic and nonmetabolic mechanisms. To determine whether HSP induction was central to the action of Gln and DON, quercetin, which blocks HSP induction, was used. Quercetin blocked HSP70 induction and the protective effect of Gln and DON. We conclude that the protective effects of Gln in intestinal epithelial cells are in part mediated by HSP70 induction.


Author(s):  
Rino P. Donato ◽  
Adaweyah El-Merhibi ◽  
Batjargal Gundsambuu ◽  
Kai Yan Mak ◽  
Emma R. Formosa ◽  
...  

2020 ◽  
Vol 318 (4) ◽  
pp. C732-C739
Author(s):  
Fangyi Liu ◽  
Xiao Wang ◽  
Hua Geng ◽  
Heng-Fu Bu ◽  
Peng Wang ◽  
...  

Sirtuin 6 (Sirt6) is predominantly expressed in epithelial cells in intestinal crypts. It plays an important role in protecting intestinal epithelial cells against inflammatory injury. Previously, we found that colitis is associated with the downregulation of Sirt6 protein in the intestines. Here, we report that murine interferon-γ (Ifnγ) inhibits Sirt6 protein but not mRNA expression in young adult mouse colonocytes (YAMC, a mouse colonic epithelial cell line) in a dose- and time-dependent manner. Using microRNA array analysis, we showed that Ifnγ induces expression of miR-92b in YAMC cells. With in silico analysis, we found that the Sirt6 3′-untranslated region (UTR) contains a putative binding site for miR-92b. Luciferase assay showed that Ifnγ inhibited Sirt6 3′-UTR activity and this effect was mimicked by miR-92b via directly targeting the miR-92b seed site in the 3′-UTR of Sirt6 mRNA. Furthermore, Western blot demonstrated that miR-92b downregulated Sirt6 protein expression in YAMC cells. Blocking miR-92b with a specific inhibitor attenuated the inhibitory effect of Ifnγ on Sirt6 protein expression in the cells. Collectively, our data suggest that Ifnγ inhibits Sirt6 protein expression in intestinal epithelial cells via a miR-92b-mediated mechanism. miR-92b may be a novel therapeutic target for rescuing Sirt6 protein levels in intestinal epithelial cells, thereby protecting against intestinal mucosal injury caused by inflammation.


2002 ◽  
Vol 195 (5) ◽  
pp. 559-570 ◽  
Author(s):  
Mathias W. Hornef ◽  
Teresa Frisan ◽  
Alain Vandewalle ◽  
Staffan Normark ◽  
Agneta Richter-Dahlfors

Toll-like receptor (TLR) 4 is mainly found on cells of the myelopoietic lineage. It recognizes lipopolysaccharide (LPS) and mediates cellular activation and production of proinflammatory cytokines. Less is known about the distribution and role of TLR4 in epithelial cells that are continuously exposed to microbes and microbial products. Here we show that the murine small intestinal epithelial cell line m-ICcl2 is highly responsive to LPS and expresses both CD14 and TLR4. Transcription and surface membrane staining for CD14 were up-regulated upon LPS exposure. Surprisingly, TLR4 immunostaining revealed a strictly cytoplasmic paranuclear distribution. This paranuclear compartment could be identified as the Golgi apparatus. LPS added to the supernatant was internalized by m-ICcl2 cells and colocalized with TLR4. Continuous exposure to LPS led to a tolerant phenotype but did not alter TLR4 expression nor cellular distribution. Thus, intestinal epithelial cells might be able to provide the initial proinflammatory signal to attract professional immune cells to the side of infection. The cytoplasmic location of TLR4, which is identical to the final location of internalized LPS, further indicates an important role of cellular internalization and cytoplasmic traffic in the process of innate immune recognition.


2001 ◽  
Vol 281 (2) ◽  
pp. G323-G332 ◽  
Author(s):  
M. C. Buresi ◽  
E. Schleihauf ◽  
N. Vergnolle ◽  
A. Buret ◽  
J. L. Wallace ◽  
...  

The thrombin receptor, protease-activated receptor-1 (PAR-1), has wide tissue distribution and is involved in many physiological functions. Because thrombin is in the intestinal lumen and mucosa during inflammation, we sought to determine PAR-1 expression and function in human intestinal epithelial cells. RT-PCR showed PAR-1 mRNA expression in SCBN cells, a nontransformed duodenal epithelial cell line. Confluent SCBN monolayers mounted in Ussing chambers responded to PAR-1 activation with a Cl−-dependent increase in short-circuit current. The secretory effect was blocked by BaCl2and the Ca2+-ATPase inhibitor thapsigargin, but not by the L-type Ca2+channel blocker verapamil or DIDS, the nonselective inhibitor of Ca2+-dependent Cl−transport. Responses to thrombin and PAR-1-activating peptides exhibited auto- and crossdesensitization. Fura 2-loaded SCBN cells had increased fluorescence after PAR-1 activation, indicating increased intracellular Ca2+. RT-PCR showed that SCBN cells expressed mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) and hypotonicity-activated Cl−channel-2 but not for the Ca2+-dependent Cl−channel-1. PAR-1 activation failed to increase intracellular cAMP, suggesting that the CFTR channel is not involved in the Cl−secretory response. Our data demonstrate that PAR-1 is expressed on human intestinal epithelial cells and regulates a novel Ca2+-dependent Cl−secretory pathway. This may be of clinical significance in inflammatory intestinal diseases with elevated thrombin levels.


2000 ◽  
Vol 74 (1) ◽  
pp. 513-517 ◽  
Author(s):  
Audrey Esclatine ◽  
Michel Lemullois ◽  
Alain L. Servin ◽  
Anne-Marie Quero ◽  
Monique Geniteau-Legendre

ABSTRACT Human cytomegalovirus (CMV) causes severe disease in immunosuppressed patients and notably infects the gastrointestinal tract. To understand the interaction of CMV with intestinal epithelial cells, which are highly susceptible to CMV infection in vivo, we used the intestinal epithelial cell line Caco-2 and demonstrated that CMV enters predominantly through the basolateral surface of polarized Caco-2 cells. As shown by expression of all three classes of CMV proteins and by visualization of nucleocapsids by transmission electron microscopy, both poorly and fully differentiated Caco-2 cells were permissive to CMV replication. However, infection failed to produce infectious particles in Caco-2 cells, irrespective of the state of differentiation.


1994 ◽  
Vol 267 (3) ◽  
pp. C776-C783 ◽  
Author(s):  
G. M. Denning ◽  
R. A. Clark ◽  
M. J. Welsh

Ca2+ plays a central role in regulating transepithelial fluid and electrolyte transport in intestinal epithelial cells. To investigate the mechanisms regulating the cytosolic free Ca2+ concentration ([Ca2+]c), we examined the effect of secretory agonists on [Ca2+]c in the intestinal epithelial cell line HT-29 clone 19A cells. We found that [Ca2+]c increased after addition of either adenosine 3',5'-cyclic monophosphate (cAMP)-dependent agonists or a D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]dependent agonist carbachol. Several lines of evidence suggest that cAMP- and Ins(1,4,5)P3-dependent agonists act through separate pathways. First, isoproterenol and forskolin increased cellular levels of cAMP but not Ins(1,4,5)P3, whereas carbachol increased cellular levels of Ins(1,4,5)P3 and stimulated inositol phosphate turnover without increasing cAMP. Second, carbachol increased [Ca2+]c by stimulating the release of Ca2+ from intracellular stores and influx of extracellular Ca2+. In contrast, cAMP agonists increased [Ca2+]c by stimulating Ca2+ influx alone. Third, the responses to maximal concentrations of cAMP agonists and carbachol were approximately additive. Finally, Ins(1,4,5)P3- but not cAMP agonist-dependent Ca2+ influx was inhibited by inorganic Ca2+ channel blockers. Thus, in intestinal epithelial cells, [Ca2+]c is regulated by at least two different second-messenger pathways, involving Ins(1,4,5)P3 or cAMP. In addition, cAMP stimulates influx of extracellular Ca2+ through a pathway distinct from that mediated by Ins(1,4,5)P3.


2017 ◽  
Vol 37 (2) ◽  
Author(s):  
Xiaoqing Wang ◽  
Weiwei Hu ◽  
Liqi Zhu ◽  
Qian Yang

Intestinal epithelial cells are the targets for transmissible gastroenteritis (TGE) virus (TGEV) infection. It is urgent to develop a novel candidate against TGEV entry. Bacillus subtilis is a probiotic with excellent anti-microorganism properties and one of its secretions, surfactin, has been regarded as a versatile weapon for most plant pathogens, especially for the enveloped virus. We demonstrate for the first time that B. subtilis OKB105 and its surfactin can effectively inhibit one animal coronavirus, TGEV, entering the intestinal porcine epithelial cell line (IPEC-J2). Then, several different experiments were performed to seek the might mechanisms. The plaque assays showed that surfactant could reduce the plaque generation of TGEV in a dose-dependent manner. Meanwhile, after incubation with TGEV for 1.5 h, B. subtilis could attach TGEV particles to their surface so that the number of virus to bind to the host cells was declined. Furthermore, our data showed that the inhibition of B. subtilis was closely related to the competition with TGEV for the viral entry receptors, including epidermal growth factor receptor (EGFR) and aminopeptidase N (APN) protein. In addition, Western blotting and apoptosis analysis indicated that B. subtilis could enhance the resistance of IPEC-J2 cells by up-regulating the expression of toll-like receptor (TLR)-6 and reducing the percentage of apoptotic cells. Taken together, our results suggest that B. subtilis OKB105 and its surfactin can antagonize TGEV entry in vitro and may serve as promising new candidates for TGEV prevention.


2001 ◽  
Vol 114 (10) ◽  
pp. 1925-1934 ◽  
Author(s):  
R. Massoumi ◽  
A. Sjolander

Local inflammatory reactions affect the integrity of intestinal epithelial cells, such as E-cadherin-mediated cell-cell interactions. To elucidate this event, we investigated the effects of an inflammatory mediator, leukotriene D(4)(LTD(4)), on the phosphorylation status and properties of vinculin, a multi-binding protein known to interact with both the E-cadherin-catenin complex and the cytoskeleton. Treatment of an intestinal epithelial cell line with LTD(4)induced rapid tyrosine phosphorylation of vinculin, which was blocked by the Src family tyrosine kinase inhibitor PP1. Simultaneously, LTD(4) caused an increased association between vinculin and actin, and that association was decreased by PP1. LTD(4) also induced dissociation of vinculin from (α)-catenin without affecting the catenin complex itself. This dissociation was not blocked by PP1 but was mimicked by the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol 13-acetate (TPA). Also, the PKC inhibitor GF109203X abolished both the LTD(4)- and the TPA-induced dissociation of vinculin from (α)-catenin. Furthermore, LTD(4) caused a colocalisation of vinculin with PKC-(α) in focal adhesions. This accumulation of vinculin was blocked by transfection with a dominant negative inhibitor of PKC (PKC regulatory domain) and also by preincubation with either GF109203X or PP1. Thus, various LTD(4)-induced phosphorylations of vinculin affect the release of this protein from catenin complexes and its association with actin, two events that are necessary for accumulation of vinculin in focal adhesions. Functionally this LTD(4)-induced redistribution of vinculin was accompanied by a PKC-dependent upregulation of active (β)1 integrins on the cell surface and an enhanced (β)1 integrin-dependent adhesion of the cells to collagen IV.


2005 ◽  
Vol 288 (2) ◽  
pp. G346-G353 ◽  
Author(s):  
Laetitia Charrier ◽  
Yutao Yan ◽  
Adel Driss ◽  
Christian L. Laboisse ◽  
Shanthi V. Sitaraman ◽  
...  

The disintegrin metalloproteases (or ADAMs) are membrane-anchored glycoproteins that have been implicated in cell-cell or cell-matrix interactions and in proteolysis of molecules on the cell surface. The expression and/or the pathophysiological implications of ADAMs are not known in intestinal epithelial cells. Therefore, our aim was to investigate the expression and the role of ADAMs in intestinal epithelial cells. Expression of ADAMs was assessed by RT-PCR, Western blot analysis, and immunufluorescence experiments. Wound-healing experiments were performed by using the electric cell substrate impedence sensing technology. Our results showed that ADAMs-10, -12, and -15 mRNA are expressed in the colonic human cell lines Caco2-BBE and HT29-Cl.19A. An ADAM-15 complementary DNA cloned from Caco2-BBE poly(A)+ RNA, and encompassing the entire coding region, was found to be shorter and to present a different region encoding the cytoplasmic tail compared with ADAM-15 sequence deposited in the database. In Caco2-BBE cells and colonic epithelial cells, ADAM-15 protein was found in the apical, basolateral, and intracellular compartments. We also showed that the overexpression of ADAM-15 reduced cell migration in a wound-healing assay in Caco2-BBE monolayers. Our data show that 1) ADAM-15 is expressed in human intestinal epithelia, 2) a new variant of ADAM-15 is expressed in a human intestinal epithelial cell line, and 3) ADAM-15 is involved in intestinal epithelial cells wound-healing processes. Together, these results suggest that ADAM-15 may have important pathophysiological roles in intestinal cells.


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