scholarly journals Mitochondrial gene expression in small intestinal epithelial cells

1995 ◽  
Vol 308 (2) ◽  
pp. 665-671 ◽  
Author(s):  
T P Mayall ◽  
I Bjarnason ◽  
U Y Khoo ◽  
T J Peters ◽  
A J S Macpherson

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.

1998 ◽  
Vol 274 (3) ◽  
pp. G472-G479 ◽  
Author(s):  
Maarten A. C. Meijssen ◽  
Steven L. Brandwein ◽  
Hans-Christian Reinecker ◽  
Atul K. Bhan ◽  
Daniel K. Podolsky

Intestinal epithelial cells may be actively involved in the immunoregulatory pathways leading to intestinal inflammation. The aim of this study was to assess expression by intestinal epithelial cells of cytokines with potential involvement in the development of intestinal inflammation in interleukin (IL)-2-deficient [(−/−)] mice. Wild-type mice, mice heterozygous for the disrupted IL-2 gene, and IL-2(−/−) mice were studied at 6, 16, and 24 wk of age. The mRNA levels of transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), IL-1β, IL-6, IL-15, KC, JE, and CD14 in colonic and small intestinal epithelial cells were assessed by Northern blot analysis. CD14 was also measured by Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR). TGF-β1 mRNA was constitutively expressed in both colonic and small intestinal epithelial cells with increased expression in the colonic epithelium of colitic mice. CD14 was detected only in colonic epithelial cells, and mRNA levels increased severalfold in IL-2(−/−) mice with colitis. Northern analysis demonstrated increased levels of TGF-β1 and CD14 mRNA in colonic epithelial cells of IL-2(−/−) mice before the development of signs of colitis. CD14 mRNA and protein expression in the epithelial cells of colitic mice were confirmed by RT-PCR and Western blot analysis of isolated cells. In addition, IL-2(−/−) mice also expressed increased levels of IL-15 mRNA in small intestinal and colonic epithelial cells compared with heterozygous control mice. TNF-α, IL-1β, IL-6, KC, and JE mRNAs were only detectable in colonic epithelial cells of mice after the onset of colitis. Enhanced expression of TGF-β1, IL-15, and CD14 by colonic epithelial cells may play a role in the subsequent development of colitis in IL-2(−/−) mice.


2016 ◽  
Vol 49 (1) ◽  
pp. 102-114 ◽  
Author(s):  
Ti-Dong Shan ◽  
Hui Ouyang ◽  
Tao Yu ◽  
Jie-Yao Li ◽  
Can-Ze Huang ◽  
...  

1998 ◽  
Vol 274 (1) ◽  
pp. C289-C294 ◽  
Author(s):  
Chandira K. Kumar ◽  
Toai T. Nguyen ◽  
Francis B. Gonzales ◽  
Hamid M. Said

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.


2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Mia Madel Alfajaro ◽  
Ji-Yun Kim ◽  
Laure Barbé ◽  
Eun-Hyo Cho ◽  
Jun-Gyu Park ◽  
...  

ABSTRACTGroup A rotaviruses, an important cause of severe diarrhea in children and young animals, initiate infection via interactions of the VP8* domain of the VP4 spike protein with cell surface sialic acids (SAs) or histo-blood group antigens (HBGAs). Although the bovine G6P[5] WC3 strain is an important animal pathogen and is also used in the bovine-human reassortant RotaTeq vaccine, the receptor(s) for the VP8* domain of WC3 and its reassortant strains have not yet been identified. In the present study, HBGA- and saliva-binding assays showed that both G6P[5] WC3 and mono-reassortant G4P[5] strains recognized the αGal HBGA. The infectivity of both P[5]-bearing strains was significantly reduced in αGal-free MA-104 cells by pretreatment with a broadly specific neuraminidase or by coincubation with the α2,6-linked SA-specificSambucus nigralectin, but not by the α2,3-linked specific sialidase or byMaackia amurensislectin. Free NeuAc and the αGal trisaccharide also prevented the infectivity of both strains. This indicated that both P[5]-bearing strains utilize α2,6-linked SA as a ligand on MA104 cells. However, the two strains replicated in differentiated bovine small intestinal enteroids and in their human counterparts that lack α2,6-linked SA or αGal HBGA, suggesting that additional or alternative receptors such as integrins, hsp70, and tight-junction proteins bound directly to the VP5* domain can be used by the P[5]-bearing strains to initiate the infection of human cells. In addition, these data also suggested that P[5]-bearing strains have potential for cross-species transmission.IMPORTANCEGroup A rotaviruses initiate infection through the binding of the VP8* domain of the VP4 protein to sialic acids (SAs) or histo-blood group antigens (HBGAs). Although the bovine G6P[5] WC3 strain is an important animal pathogen and is used as the backbone in the bovine-human reassortant RotaTeq vaccine, the receptor(s) for their P[5] VP8* domain has remained elusive. Using a variety of approaches, we demonstrated that the WC3 and bovine-human mono-reassortant G4P[5] vaccine strains recognize both α2,6-linked SA and αGal HBGA as ligands. Neither ligand is expressed on human small intestinal epithelial cells, explaining the absence of natural human infection by P[5]-bearing strains. However, we observed that the P[5]-bearing WC3 and G4P[5] RotaTeq vaccine strains could still infect human intestinal epithelial cells. Thus, the four P[5] RotaTeq vaccine strains potentially binding to additional alternative receptors may be efficient and effective in providing protection against severe rotavirus disease in human.


2021 ◽  
Vol 534 ◽  
pp. 639-645
Author(s):  
Jung-ha Park ◽  
In kyo Jung ◽  
Yongjun Lee ◽  
Soojung Jin ◽  
Hee Jung Yun ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Orsolya Palócz ◽  
Géza Szita ◽  
György Csikó

The intestinal epithelium is the first determining barrier to the drugs administered per os. Cytochrome P450 (CYP) enzymes are substantial in the initial step of xenobiotic metabolism; therefore, intestinal CYP enzyme activities could be an important influencing factor of the oral utilization of xenobiotic substances. In this study, the effect of four drinking water supplements on CYP mRNA levels of porcine intestinal epithelial cells was examined. Further goal of the study is to describe the effect of these feed additives on the proinflammatory response of the LPS-treated enterocytes. The nontransformed porcine intestinal epithelial cells (IPEC-J2) were grown on six-well polyester membrane inserts. Cell cultures were treated with LPS (10 μg/ml), β-glucan (5 and 50 μg/ml), sanguinarine-containing additive (5 and 50 μg/ml), drinking water acidifier (0.1 and 1 μl/ml), and fulvic acid (25 and 250 μg/ml) for 1 hour. Cells were washed with culture medium and incubated for additional 1 h before total RNA isolation. IL-6, IL-8, TNF-α, HSP70, CYP1A1, CYP1A2, and CYP3A29 mRNA levels were measured. The LPS treatment upregulated the gene expression of IL-8 and TNF-α. The relative gene expression of IL-6 remained unchanged and TNF-α and HSP70 were downregulated after the treatment with each feed additive. CYP1A1 and CYP1A2 expressions increased after sanguinarine-containing solution, fulvic acid, and drinking water acidifier treatment. None of the treatments changed the gene expression of CYP3A29, responsible for the metabolism of the majority of drug substances used in swine industry. The feed additive substances inhibited the expression of proinflammatory mediators HSP70 and TNF-α; however, β-glucan and fulvic acid elevated the production of the chemokine IL-8 mRNA in endotoxin-treated enterocytes. All acidic supplements increased the expression of CYP1A1 gene; their constituents may serve as a ligand of CYP1A1 nuclear receptors.


Sign in / Sign up

Export Citation Format

Share Document