Baicalin-Induced Autophagy Preserved LPS-Stimulated Intestinal Cells from Inflammation and Alterations of Paracellular Permeability

Several studies have demonstrated a relevant role of intestinal epithelial cells in the immune response and in chronic inflammatory conditions, including ulcers, colitis, and Crohn’s disease. Baicalin (BA), extracted from the root of Scutellaria baicalensis, has various beneficial healthy effects, including anti-inflammatory activity. However, few studies have evaluated BA effects on autophagic signaling in epithelial cell response to inflammatory stimuli. To explore possible beneficial effects of BA, HT-29 cells were exposed to lipopolysaccharide (LPS), in presence or absence of BA, for 4 h. We evaluated mRNA levels of autophagy-related genes and cytokines, triggering inflammatory response. Furthermore, the expression of claudin 1, involved in the regulation of paracellular permeability was analyzed. BA treatment repressed LPS-induced expression of TNF-α and IL-1β. The down-regulation of autophagy-related genes induced by LPS was counteracted by cell pretreatment with BA. Under these conditions, BA reduced the NF-κB activation caused by LPS. Also, BA restored mRNA and protein levels of claudin 1, which were reduced by LPS. In conclusion, in intestinal epithelial cells BA regulates the NF-κB activation and modulates both autophagic and inflammatory processes, leading to an improvement of paracellular permeability. These results suggest that the anti-inflammatory effects of BA can be associated to the regulation of autophagic flux.

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Basic helix–loop–helix protein E47-mediated p21Waf1/Cip1 gene expression regulates apoptosis of intestinal epithelial cells

Biochemical Journal ◽

10.1042/bj20070293 ◽

2007 ◽

Vol 407 (2) ◽

pp. 243-254 ◽

Cited By ~ 8

Author(s):

Sujoy Bhattacharya ◽

Huazhang Guo ◽

Ramesh M. Ray ◽

Leonard R. Johnson

Keyword(s):

Epithelial Cells ◽

Caspase 3 ◽

Intestinal Epithelial Cells ◽

Mrna Levels ◽

Intestinal Epithelial ◽

Protein Levels ◽

Basic Helix Loop Helix ◽

Helix Loop Helix ◽

Apoptotic Protein

Inhibition of ornithine decarboxylase by DFMO (α-difluromethylornithine) and subsequent polyamine depletion increases p21Cip1 protein, induces cell cycle arrest and confers resistance to apoptosis on intestinal epithelial cells. However, the mechanism by which polyamines regulate p21Cip1 expression and apoptosis is unknown. On the basis of the involvement of p21Cip1 as an anti-apoptotic protein, we tested the role of p21Cip1 in providing protection from apoptosis. Simultaneously, we investigated the role of E47, a basic helix–loop–helix protein, in the regulation of p21Cip1 gene transcription. Gene-specific siRNA (small interfering RNA) decreased E47 protein levels, increased p21Cip1 promoter activity and protein levels and protected cells from TNFα (tumour necrosis factor α)-induced apoptosis. Knockdown of p21Cip1 protein by siRNA resulted in cells becoming more susceptible to apoptosis. In contrast, incubation with EGF (epidermal growth factor) stimulated p21Cip1 mRNA and protein levels and rescued cells from apoptosis. During apoptosis, the level of E47 mRNA increased, causing a concomitant decrease in p21Cip1 mRNA and protein levels. Polyamine depletion decreased E47 mRNA levels and cell survival. Caspase 3-mediated cleavage of p130Cas has been implicated in p21Cip1 transcription. The progression of apoptosis led to a caspase 3-dependent cleavage of p130Cas and generated a 31 kDa fragment, which translocated to the nucleus, associated with nuclear E47 and inhibited p21Cip1 transcription. Polyamine depletion inhibited all these effects. Transient expression of the 31 kDa fragment prevented the expression of p21Cip1 protein and increased apoptosis. These results implicate p21Cip1 as an anti-apoptotic protein and suggest a role for polyamines in the regulation of p21Cip1 via the transcription repressor E47. Caspase-mediated cleavage of p130Cas generates a 31 kDa fragment, inhibits p21Cip1 transcription and acts as an amplifier of apoptotic signalling.

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Clostridium difficile toxins A and B decrease intestinal SLC26A3 protein expression

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00307.2017 ◽

2018 ◽

Vol 315 (1) ◽

pp. G43-G52 ◽

Cited By ~ 5

Author(s):

Hayley Coffing ◽

Shubha Priyamvada ◽

Arivarasu N. Anbazhagan ◽

Christine Salibay ◽

Melinda Engevik ◽

...

Keyword(s):

Clostridium Difficile ◽

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Critical Factor ◽

The United States ◽

Mrna Levels ◽

Apical Surface ◽

Intestinal Epithelial ◽

Protein Levels ◽

Anion Transporter

Clostridium difficile infection (CDI) is the primary cause of nosocomial diarrhea in the United States. Although C. difficile toxins A and B are the primary mediators of CDI, the overall pathophysiology underlying C. difficile-associated diarrhea remains poorly understood. Studies have shown that a decrease in both NHE3 (Na+/H+ exchanger) and DRA (downregulated in adenoma, Cl−/[Formula: see text] exchanger), resulting in decreased electrolyte absorption, is implicated in infectious and inflammatory diarrhea. Furthermore, studies have shown that NHE3 is depleted at the apical surface of intestinal epithelial cells and downregulated in patients with CDI, but the role of DRA in CDI remains unknown. In the current studies, we examined the effects of C. difficile toxins TcdA and TcdB on DRA protein and mRNA levels in intestinal epithelial cells (IECs). Our data demonstrated that DRA protein levels were significantly reduced in response to TcdA and TcdB in IECs in culture. This effect was also specific to DRA, as NHE3 and PAT-1 (putative anion transporter 1) protein levels were unaffected by TcdA and TcdB. Additionally, purified TcdA and TcdA + TcdB, but not TcdB, resulted in a decrease in colonic DRA protein levels in a toxigenic mouse model of CDI. Finally, patients with recurrent CDI also exhibited significantly reduced expression of colonic DRA protein. Together, these findings indicate that C. difficile toxins markedly downregulate intestinal expression of DRA which may contribute to the diarrheal phenotype of CDI. NEW & NOTEWORTHY Our studies demonstrate, for the first time, that C. difficile toxins reduce DRA protein, but not mRNA, levels in intestinal epithelial cells. These findings suggest that a downregulation of DRA may be a critical factor in C. difficile infection-associated diarrhea.

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Antioxidant and anti-inflammatory potential of Aloe vera and Punica granatum: onconutraceutical potential in intestinal epithelial cells

10.1055/s-0039-3399962 ◽

2019 ◽

Author(s):

SF Rapa ◽

G Pepe ◽

D Cianciarulo ◽

F Merciai ◽

E Salviati ◽

...

Keyword(s):

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Aloe Vera ◽

Punica Granatum ◽

Intestinal Epithelial ◽

Anti Inflammatory

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Protective Effects of Lactoferrin against SARS-CoV-2 Infection In Vitro

Nutrients ◽

10.3390/nu13020328 ◽

2021 ◽

Vol 13 (2) ◽

pp. 328 ◽

Cited By ~ 1

Author(s):

Claudio Salaris ◽

Melania Scarpa ◽

Marina Elli ◽

Alice Bertolini ◽

Simone Guglielmetti ◽

...

Keyword(s):

Immune Response ◽

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Plaque Assay ◽

Immune Response Gene ◽

Intestinal Epithelial ◽

Antiviral Immune Response ◽

Qrt Pcr ◽

Anti Inflammatory

SARS-CoV-2 is a newly emerging virus that currently lacks curative treatments. Lactoferrin (LF) is a naturally occurring non-toxic glycoprotein with broad-spectrum antiviral, immunomodulatory and anti-inflammatory effects. In this study, we assessed the potential of LF in the prevention of SARS-CoV-2 infection in vitro. Antiviral immune response gene expression was analyzed by qRT-PCR in uninfected Caco-2 intestinal epithelial cells treated with LF. An infection assay for SARS-CoV-2 was performed in Caco-2 cells treated or not with LF. SARS-CoV-2 titer was determined by qRT-PCR, plaque assay and immunostaining. Inflammatory and anti-inflammatory cytokine production was determined by qRT-PCR. LF significantly induced the expression of IFNA1, IFNB1, TLR3, TLR7, IRF3, IRF7 and MAVS genes. Furthermore, LF partially inhibited SARS-CoV-2 infection and replication in Caco-2 intestinal epithelial cells. Our in vitro data support LF as an immune modulator of the antiviral immune response with moderate effects against SARS-CoV-2 infection.

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Comparison of intestinal folate carrier clone expressed in IEC-6 cells and in Xenopusoocytes

AJP Cell Physiology ◽

10.1152/ajpcell.1998.274.1.c289 ◽

1998 ◽

Vol 274 (1) ◽

pp. C289-C294 ◽

Cited By ~ 59

Author(s):

Chandira K. Kumar ◽

Toai T. Nguyen ◽

Francis B. Gonzales ◽

Hamid M. Said

Keyword(s):

Folic Acid ◽

Epithelial Cells ◽

Cdna Clone ◽

Xenopus Oocytes ◽

Intestinal Epithelial Cells ◽

Maximal Velocity ◽

Mrna Levels ◽

Acidic Ph ◽

Intestinal Epithelial ◽

Folate Transport

We recently identified a cDNA clone from mouse small intestine, which appears to be involved in folate transport when expressed in Xenopus oocytes. The open reading frame of this clone is identical to that of the reduced folate carrier (RFC) (K. H. Dixon, B. C. Lanpher, J. Chiu, K. Kelley, and K. H. Cowan. J. Biol. Chem. 269: 17–20, 1994). The characteristics of this cDNA clone [previously referred to as intestinal folate carrier 1 (IFC-1)] expressed in Xenopus oocytes, however, were found to be different from the characteristics of folate transport in native small intestinal epithelial cells. To further study these differences, we determined the characteristics of RFC when expressed in an intestinal epithelial cell line, IEC-6, and compared the findings to its characteristics when expressed in Xenopus oocytes. RFC was stably transfected into IEC-6 cells by electroporation; its cRNA was microinjected into Xenopus oocytes. Northern blot analysis of poly(A)+RNA from IEC-6 cells stably transfected with RFC cDNA (IEC-6/RFC) showed a twofold increase in RFC mRNA levels over controls. Similarly, uptake of folic acid and 5-methyltetrahydrofolate (5-MTHF) by IEC-6/RFC was found to be fourfold higher than uptake in control sublines. This increase in folic acid and 5-MTHF uptake was inhibited by treating IEC-6/RFC cells with cholesterol-modified antisense DNA oligonucleotides. The increase in uptake was found to be mainly mediated through an increase in the maximal velocity ( V max) of the uptake process [the apparent Michaelis-Menten constant ( K m) also changed (range was 0.31 to 1.56 μM), but no specific trend was seen]. In both IEC-6/RFC and control sublines, the uptake of both folic acid and 5-MTHF displayed 1) pH dependency, with a higher uptake at acidic pH 5.5 compared with pH 7.5, and 2) inhibition to the same extent by both reduced and oxidized folate derivatives. These characteristics are very similar to those seen in native intestinal epithelial cells. In contrast, RFC expressed in Xenopus oocytes showed 1) higher uptake at neutral and alkaline pH 7.5 compared with acidic pH 5.5 and 2) higher sensitivity to reduced compared with oxidized folate derivatives. Results of these studies demonstrate that the characteristics of RFC vary depending on the cell system in which it is expressed. Furthermore, the results may suggest the involvement of cell- or tissue-specific posttranslational modification(s) and/or the existence of an auxiliary protein that may account for the differences in the characteristics of the intestinal RFC when expressed in Xenopus oocytes compared with when expressed in intestinal epithelial cells.

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Mitochondrial gene expression in small intestinal epithelial cells

Biochemical Journal ◽

10.1042/bj3080665 ◽

1995 ◽

Vol 308 (2) ◽

pp. 665-671 ◽

Cited By ~ 5

Author(s):

T P Mayall ◽

I Bjarnason ◽

U Y Khoo ◽

T J Peters ◽

A J S Macpherson

Keyword(s):

Epithelial Cells ◽

Cytochrome Oxidase ◽

Cytochrome B ◽

Intestinal Epithelial Cells ◽

Mitochondrial Gene ◽

Cytochrome Oxidase I ◽

Mrna Levels ◽

Intestinal Epithelial ◽

Mitochondrial Transcription Factor ◽

Small Intestinal

Most mitochondrial genes are transcribed as a single large transcript from the heavy strand of mitochondrial DNA, and are subsequently processed into the proximal mitochondrial (mt) 12 S and 16 S rRNAs, and the more distal tRNAs and mRNAs. We have shown that in intestinal epithelial biopsies the steady-state levels of mt 12 S and 16 S rRNA are an order of magnitude greater than those of mt mRNAs. Fractionation of rat small intestinal epithelial cells on the basis of their maturity has shown that the greatest ratios of 12 S mt rRNA/cytochrome b mt mRNA or 12 S mt rRNA/cytochrome oxidase I mt mRNA are found in the surface mature enterocytes, with a progressive decrease towards the crypt immature enteroblasts. Cytochrome b and cytochrome oxidase I mt mRNA levels are relatively uniform along the crypt-villus axis, but fractionation experiments showed increased levels in the crypt base. The levels of human mitochondrial transcription factor A are also greater in immature crypt enteroblasts compared with mature villus enterocytes. These results show that the relative levels of mt rRNA and mRNA are distinctly regulated in intestinal epithelial cells according to the crypt-villus position and differentiation status of the cells, and that there are higher mt mRNA and mt TFA levels in the crypts, consistent with increased transcriptional activity during mitochondrial biogenesis in the immature enteroblasts.

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