Villus Cells Research Articles

Експресія генів CFTR, SLC9A3 та SNN1B в епітеліоцитах дванадцятипалої кишки щурів за умов тривалої шлункової гіпохлоргідрії та при введенні мультипробіотика

The increasing of Cftr, Slc9a3 and the decreasing of Snn1b gene's expression in rat duodenal villus and crypt epithelial cells against the background of intensification of free radical formation upon gastric hypoacidic conditions were shown. The level of above mentioned gene's expression both in villus and crypt epitheliocytes approached to the control value upon the treatment of hypoacidic rats with multiprobiotic Symbiter.

Metabolomic analysis of intestinal epithelial cell maturation along the crypt–villus axis

The present experiment showed a gradual change in the metabolism of intestinal epithelial cells during maturation along CVA. Metabolism of fatty acids, amino acids, and glucose was significantly different between villus and crypt cells.

The impact of oxidative stress on Par2, Ptgs2 genes expression in rat duodenal epithelial cells under conditions of prolonged gastric hypochlorhydria and with administration of multiprobiotic

Development of dysbiosis is a key consequence of long hypoacidity, in which there is colonization of the gastrointestinal tract by pathogenic microflora that forms source of sustainable endogenous infection and leads to inflammation. The prevalence of free-radical processes of antioxidant defense system is an important pathogenetic link in the origin and development of various disorders. Because reactive oxygen species are important for transcription of Ptgs2 gene, the relationship between oxidative stress, antioxidant element and PAR2-mediated signaling pathways may take place under conditions of dysbiotic changes due to hypochlorhydria. To evaluate the intensity of free radical processes and their impact on Par2, Ptgs2 genes expression in rat duodenal epithelial cells under conditions of prolonged gastric hypochlorhydria and with administration of multiprobiotic. Four experimental groups were created with 8 rats in each. One group was a control, while others were injected with acid suppressant omeprazole or multi-strain probiotic preparation or with both compounds simultaneously for 28 days. Protein oxidative modification products, free SH-groups, metallothioneins content were measured in villus and crypt epithelial cells with standard biochemical assays. Level of Par2, Ptgs2 genes mRNA was determined with semi-quantitative RT-PCR. Prolonged inhibition of acid secretion in stomach was accompanied by significant elevation of free radical processes (intensification of protein oxidative modification, free SH-groups pool reduction, changes of metallothioneins concentration) and elevation of Par2 and Ptgs2 genes expression levels in rat duodenal epithelial cells. Reduction of free radical processes intensity; restoration of redox balance and the normalization of Par2, Ptgs2 gene expression pattern in the duodenum upon the simultaneous administration of the multiprobiotic Symbiter were observed. Par2 overexpression leads to activation Ptgs2 on the background of free radical processes over the antioxidant defense system in the development of inflammation in the duodenum through dysbiotic changes in the conditions of prolonged hypochlorhydria.

Distinct Processes and Transcriptional Targets Underlie CDX2 Requirements in Intestinal Stem Cells and Differentiated Villus Cells

SummaryLgr5-expressing intestinal stem cells (ISCs) renew the adult gut epithelium by producing mature villus cells (VCs); the transcriptional basis for ISC functions remains unclear. RNA sequencing analysis identified transcripts modulated during differentiation of Lgr5+ ISCs into VCs, with high expression of the intestine-restricted transcription factor (TF) gene Cdx2 in both populations. Cdx2-deleted mouse ISCs showed impaired proliferation and long-term inability to produce mature lineages, revealing essential ISC functions. Chromatin immunoprecipitation sequencing analysis of CDX2 in Lgr5+ ISCs, coupled with mRNA profiling of control and Cdx2−/− ISCs, identified features of CDX2 regulation distinct from VCs. Most CDX2 binding in ISCs occurs in anticipation of future gene expression, but whereas CDX2 primarily activates VC genes, direct ISC targets are activated and repressed. Diverse CDX2 requirements in stem and differentiated cells may reflect the versatility of TFs that specify a tissue in development and control the same tissue in adults.

Generation of Human Induced Pluripotent Stem Cells from Extraembryonic Tissues of Fetuses Affected by Monogenic Diseases.

The generation of human induced pluripotent stem cells (hiPSCs) derived from an autologous extraembryonic fetal source is an innovative personalized regenerative technology that can transform own-self cells into embryonic stem-like ones. These cells are regarded as a promising candidate for cell-based therapy, as well as an ideal target for disease modeling and drug discovery. Thus, hiPSCs enable researchers to undertake studies for treating diseases or for future applications of in utero therapy. We used a polycistronic lentiviral vector (hSTEMCCA-loxP) encoding OCT4, SOX2, KLF4, and cMYC genes and containing loxP sites, excisible by Cre recombinase, to reprogram patient-specific fetal cells derived from prenatal diagnosis for several genetic disorders, such as myotonic dystrophy type 1 (DM1), β-thalassemia (β-Thal), lymphedema-distichiasis syndrome (LDS), spinal muscular atrophy (SMA), cystic fibrosis (CF), as well as from wild-type (WT) fetal cells. Because cell types tested to create hiPSCs influence both the reprogramming process efficiency and the kinetics, we used chorionic villus (CV) and amniotic fluid (AF) cells, demonstrating how they represent an ideal cell resource for a more efficient generation of hiPSCs. The successful reprogramming of both CV and AF cells into hiPSCs was confirmed by specific morphological, molecular, and immunocytochemical markers and also by their teratogenic potential when inoculated in vivo. We further demonstrated the stability of reprogrammed cells over 10 and more passages and their capability to differentiate into the three embryonic germ layers, as well as into neural cells. These data suggest that hiPSCs-CV/AF can be considered a valid cellular model to accomplish pathogenesis studies and therapeutic applications.

Epigenetic regulation of the intestinal epithelium.

The intestinal epithelium is an ideal model system for the study of normal and pathological differentiation processes. The mammalian intestinal epithelium is a single cell layer comprising proliferative crypts and differentiated villi. The crypts contain both proliferating and quiescent stem cell populations that self-renew and produce all the differentiated cell types, which are replaced every 3-5days. The genetics of intestinal development, homeostasis, and disease are well defined, but less is known about the contribution of epigenetics in modulating these processes. Epigenetics refers to heritable phenotypic traits, including gene expression, which are independent of mutations in the DNA sequence. We have known for several decades that human colorectal cancers contain hypomethylated DNA, but the causes and consequences of this phenomenon are not fully understood. In contrast, tumor suppressor gene promoters are often hypermethylated in colorectal cancer, resulting in decreased expression of the associated gene. In this review, we describe the role that epigenetics plays in intestinal homeostasis and disease, with an emphasis on results from mouse models. We highlight the importance of producing and analyzing next-generation sequencing data detailing the epigenome from intestinal stem cell to differentiated intestinal villus cell.

Mast cell regulation of Na-glutamine co-transporters B0AT1 in villus and SN2 in crypt cells during chronic intestinal inflammation.

BackgroundIn the chronically inflamed rabbit small intestine, brush border membrane (BBM) Na-glutamine co-transport is inhibited in villus cells (mediated by B0AT1), while it is stimulated in crypt cells (mediated by SN2/SNAT5). How mast cells, known to be enhanced in the chronically inflamed intestine, may regulate B0AT1 in villus and SN2/SNAT5 in crypt cell is unknown. Thus, the aim of the present study is to determine the regulation of B0AT1 and SN2/SNAT5 by mast cells during chronic enteritis.MethodsChronic intestinal inflammation was induced in male rabbits with intra-gastric inoculation of Eimeria magna oocytes. Rabbits with chronic inflammation were treated with ketotifen (10 mg/day) or saline (Placebo) for 2 days. Villus and crypts cells were isolated from the rabbit intestine using the Ca++ chelation technique. Na/K-ATPase activity was measured as Pi from cellular homogenate. BBM vesicles (BBMV) were prepared from villus and crypt cells and uptake studies were performed using rapid filtration technique with 3H-Glutamine. Western blot analyses were done using B0AT1 and SN2 specific antibodies.ResultsIn villus cells, Na-glutamine co-transport inhibition observed during inflammation was completely reversed by ketotifen, a mast cell stabilizer. In contrast, in crypt cells, Na-glutamine co-transport stimulation was reversed to normal levels by ketotifen. Kinetic studies demonstrated that ketotifen reversed the inhibition of B0AT1 in villus cells by restoring co-transporter numbers in the BBM, whereas the stimulation of SN2/SNAT5 in crypts cells was reversed secondary to restoration of affinity of the co-transporter. Western blot analysis showed that ketotifen restored immune-reactive levels of B0AT1 in villus cells, while SN2/SNAT5 levels from crypts cell remained unchanged.ConclusionIn the present study we demonstrate that mast cells likely function as a common upstream immune pathway regulator of the Na-dependent glutamine co-transporters, B0AT1 in villus cells and SN2 in crypts cells that are uniquely altered in the chronically inflamed small intestine.

Endogenous Life Cycle of Eimeria marmosopos (Apicomplexa: Eimeriidae) from the Opossum, Didelphis marsupialis (Didelphimorphia: Didelphidae) in Costa Rica.

The endogenous life cycle of Eimeria marmosopos was studied in experimentally infected young opossums, Didelphis marsupialis . All the endogenous stages were located in the epithelial cells of villi in the small intestine. Giemsa-stained mucosal scrapings and histological sections were studied for the diagnosis of all the life cycle stages. Eimeria marmosopos has 3 generations of meronts (M) that differ by size, shape, and number of merozoites (m), which also differ in their size, shape, and location of their nuclei within the cytoplasm of the meronts. The 3 meront types, M(1)-M(3), respectively, had 8-15 (m(1)), 4-9 (m(2)), and 22-30 (m(3)) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, completed the sexual cycle, finishing with the formation of unsporulated oocysts. This parasite's endogenous development produced severe intestinal lesions in experimentally infected opossums. There are 56 Eimeria species known from all marsupials worldwide, but this is the first complete life cycle in which both the asexual and sexual stages have been documented.

Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells

Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-D-[(3)H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter.

Interaction of glucose transporters SGLT1 and GLUT2 with cytoskeleton in enterocytes and Caco2 cells during hexose absorption

The distribution of cytoskeleton elements (microtubules and actin filaments) and glucose transporters SGLT1 or GLUT2 in enterocyte of rat intestine and Caco2 cells during hexose absorption was studied. Confocal microscopy revealed that the distribution of SGLT1 and GLUT2 transporters in absorptive cells of the intestinal villus was altered depending on maltose concentration. The transporters were colocalized with actin. An increased number of vesicles close to microtubules in the apical cell part during absorption of high hexoze concentration was observed with electron microscopy. This observation, as well as uncovered colocalization of the transporters and actin, as well as actin and α-tubulin, suggests that elements of the cytoskeleton participate in the translocation of glucose transporters to the apical cell membrane.

Effect of transvaginal ultrasound on human chorionic villus cell apoptosis during pregnancy.

With the advancement of ultrasonic technology in recent years, sonography has become a common medical diagnostic tool, as it has elevated output sonic intensity and elongated exposure time. This study investigates the effect of ultrasound on human chorionic villus cell apoptosis during early pregnancy. Transvaginal ultrasound was performed for a total of 60 women who had undergone induced abortion at our hospital. They were randomly divided into the control, short ultrasound (10 min), and long ultrasound (20 min) groups (N = 20 each). Twenty-four hours after ultrasonic exposure, chorionic villus tissues were extracted during induced abortion, and were tested for cell apoptosis using flow cytometry. Bax and B cell lymphoma-2 (Bcl-2) protein levels were also quantified by immunohistochemistry. We found that the long ultrasound group had significantly higher cell apoptosis rates compared to the short ultrasound group, which in turn had higher rates compared to the control group (P < 0.05 in both cases). Bax protein levels were elevated in both the long and short ultrasound groups (P < 0.05). Bcl-2 proteins in two ultrasound groups, however, were downregulated as compared to those in the control group (P < 0.05). It is therefore possible that transvaginal sonography can potentiate the apoptosis of human chorionic villus cells by increasing the Bax/Bcl-2 protein ratio.

Molecular mechanism of regulation of villus cell Na-K-ATPase in the chronically inflamed mammalian small intestine

Na-K-ATPase located on the basolateral membrane (BLM) of intestinal epithelial cells provides a favorable intracellular Na+ gradient to promote all Na dependent co-transport processes across the brush border membrane (BBM). Down-regulation of Na-K-ATPase activity has been postulated to alter the absorption via Na-solute co-transporters in human inflammatory bowel disease (IBD). Further, the altered activity of a variety of Na-solute co-transporters in intact villus cells has been reported in animal models of chronic enteritis. But the molecular mechanism of down-regulation of Na-K-ATPase is not known. In the present study, using a rabbit model of chronic intestinal inflammation, which resembles human IBD, Na-K-ATPase in villus cells was shown to decrease. The relative mRNA abundance of α-1 and β-1 subunits was not altered in villus cells during chronic intestinal inflammation. Similarly, the protein levels of these subunits were also not altered in villus cells during chronic enteritis. However, the BLM concentration of α-1 and β-1 subunits was diminished in the chronically inflamed intestinal villus cells. An ankyrin–spectrin skeleton is necessary for the proper trafficking of Na-K-ATPase to the BLM of the cell. In the present study, ankyrin expression was markedly diminished in villus cells from the chronically inflamed intestine resulting in depolarization of ankyrin-G protein. The decrease of Na-K-ATPase activity was comparable to that seen in ankyrin knockdown IEC-18 cells. Therefore, altered localization of Na-K-ATPase as a result of transcriptional down-regulation of ankyrin-G mediates the down-regulation of Na-K-ATPase activity during chronic intestinal inflammation.

YAP/TAZ Join the Play with β-catenin to Orchestrate Wnt Signaling

For the purpose of studying Wnt signaling, the intestinal epithelium has been the most relevant biological tissue for its differential topology expression of Wnt signaling: active in all crypt cells (helping in proliferation, stemness, regeneration, and tissue homeostasis) and inactive in the villi cells. Interestingly though, YAP/TAZ regulation through Wnt signaling has been more controversial and the subject of this review. Recent work shows that Wnt signaling inactivates the cytoplasmic pool of destruction complex through dissociating β-TrCP E3 ligase from the complex. Further, in addition to βcatenin, YAP and TAZ, two related proteins known for their roles in the Hippo signaling cascade, are two other pivotal regulators of cell proliferation and stemness during organ growth, regeneration, and tumorigenesis. The biological function of YAP/TAZ and β-catenin overlap to suggest that these factors are not completely independent of one another and may influence each other’s activities.

Genome-wide expression analysis in fibroblast cell lines from probands with Pallister Killian syndrome.

Pallister Killian syndrome (OMIM: # 601803) is a rare multisystem disorder typically caused by tissue limited mosaic tetrasomy of chromosome 12p (isochromosome 12p). The clinical manifestations of Pallister Killian syndrome are variable with the most common findings including craniofacial dysmorphia, hypotonia, cognitive impairment, hearing loss, skin pigmentary differences and epilepsy. Isochromosome 12p is identified primarily in skin fibroblast cultures and in chorionic villus and amniotic fluid cell samples and may be identified in blood lymphocytes during the neonatal and early childhood period. We performed genomic expression profiling correlated with interphase fluorescent in situ hybridization and single nucleotide polymorphism array quantification of degree of mosaicism in fibroblasts from 17 Caucasian probands with Pallister Killian syndrome and 9 healthy age, gender and ethnicity matched controls. We identified a characteristic profile of 354 (180 up- and 174 down-regulated) differentially expressed genes in Pallister Killian syndrome probands and supportive evidence for a Pallister Killian syndrome critical region on 12p13.31. The differentially expressed genes were enriched for developmentally important genes such as homeobox genes. Among the differentially expressed genes, we identified several genes whose misexpression may be associated with the clinical phenotype of Pallister Killian syndrome such as downregulation of ZFPM2, GATA6 and SOX9, and overexpression of IGFBP2.

Effects of whole-grain paddy rice replacement with or without enzyme addition on broiler performance and intestinal morphology

1. To investigate the effect of replacing maize with whole-grain paddy rice (WPR) in broiler chicken diets, with or without enzyme addition, on growth performance and histological structures of the intestinal villi, 14-d-old Marshall Chunky male chicks were divided into 4 groups with 4 replicates of 4 chicks each. The experimental diets containing different concentrations of WPR were as follows: (1) 0 g/kg (Control); (2) 141.5 g/kg, grower, and 125.0 g/kg, finisher (25WPR); (3) 283.0 g/kg, grower, and 250.0 g/kg, finisher (50WPR); (4) 283.0 g/kg, grower, and 250.0 g/kg, finisher, and enzyme supplementation (50WPR + enzyme). All diets were formulated to be isocaloric and isonitrogenous and provided ad libitum for 35 d.2. There were no differences among the diets on the growth performance and digestive organ size.3. The villus height and cell mitosis number of all intestinal segments did not change in any treatment. The ileal villus area, duodenal cell area, duodenal and jejunal goblet cell number in the 50WPR group increased significantly relative to the control but not when enzyme was included.4. In the scanning electron microscope results, all experimental groups showed clear protuberant cells and cell clusters on the villus apical surface of the duodenum. In the jejunum, cell clusters and areas having cells with no microvilli were frequently found in both the 50WPR and 50WPR + enzyme groups.5. In conclusion, broilers fed on diets replacing maize with WPR showed hypertrophied villi of duodenum and ileum and epithelial cells in duodenum and jejunum, especially in the 50WPR group, without negatively affecting growth performance. These findings suggest that WPR can replace maize up to a level of 50% (283.0 g/kg, starter, and 250.0 g/kg, finisher) in broiler diets without enzyme supplementation. However, further studies are needed to improve our knowledge of the influence of WPR on higher numbers of birds.

Toxoplasma gondii and Neospora caninum infections in goat abortions from Argentina

The aims of this study were to identify the occurrence of Toxoplasma gondii and Neospora caninum abortions in goats from Argentina by serological, macroscopical and microscopical examination and bioassay, and to characterize the obtained isolates by molecular techniques. For this purpose, 25 caprine fetal fluids, 18 caprine fetal brains and 10 caprine placentas from 8 dairy/meat goat farms from Argentina were analyzed. Gestational age of the aborted fetuses was determined in 18 cases. Protozoal infections were detected by at least one of the applied diagnostic techniques in 44% (11/25) of examined fetuses; specifically, 24% (6/25) were positive to T. gondii, 8% (2/25) were positive to N. caninum and 12% (3/25) were positive to both parasites. In this study IFAT titers were similarly distributed in younger and older fetuses. Macroscopical and microscopical examination of one placenta revealed chalky nodules in the fetal cotyledons and normal intercotyledonary areas, as well as necrosis and calcification of mesenchymal cells in villi. Tachyzoites were observed in peritoneal wash from 2 mice inoculated with brain and a pool of brain and placenta of two fetuses. Cell culture growth of tachyzoites was achieved from one inoculated mouse, and confirmed as T. gondii by PCR. The T. gondii isolate was identified as atypical or non-canonical by nested-PCR-RFLP. This is the first study that investigated the involvement of N. caninum and T. gondii in cases of goat abortion in Argentina.

Histopathological and histochemical studies on naturally occurring coccidial infections in caprines of Marathwada region

The histopathological and histochemical studies of intestines of goats affected with various species of Eimeria were conducted. Goats revealed acute to chronic enteritis evidenced by minimal to mild desquamation, disruption and exfoliation of glandular epithelial cells with bluntness of villi, exudation at the tip of villus, mild to moderate infiltration of polymorphonuclear cells, plasma cells, eosinophills and macrophages. In addition, there was hypertrophy and hyperplasia of epithelium of villi with goblet cell hyperplasia. The mature macrogamete contained a large number of eosinophilic granules, whereas, the microgametes showed presence of whorls formed by granules within them. The tissue sections stained with PAS revealed moderate positivity for presence of glycogen specially within the epithelial cells of villi wherein the schizont lodgement was marked. The tissue sections exposed to PAS Alcian blue staining revealed mild to intense positive reaction for mucin specially at the places in villus having the lodgment of gametocytes, whereas, the reaction at other portion of small intestines without invasion of endogenous stages, appeared to be comparatively less positive.

Effect of Curcumin Supplementation on Hepatic, Renal and Intestinal Organization of Anabas testudineus (Bloch): Light and Electron Microscopic Studies

The ultrastructure of hepatic, renal and intestinal tissues of Anabas testudineus and the influence of dietary curcumin (0.5 and 1% for 6 months) on the organization of these tissues were studied. The results revealed an increased vascularity in curcumin-treated fish liver. The size of hepatopancreas and its nuclei and melanomacrophage centres increased in the treated liver while size of hepatocytes and their nuclei remained unchanged. The hypertrophy and hyper-activity of hepatopancreas might provide for proper digestion and absorption of food. In the intestine, the number of goblet's cells in the villi decreased in the curcumin treated group which might help the retention of food in the intestine. Therefore, based on the above results it can be concluded that curcumin is beneficial to fish and, so, could be of application in aquaculture practices.

Enterocyte-specific Regulation of the Apical Nutrient Transporter SLC6A19 (B0AT1) by Transcriptional and Epigenetic Networks

Enterocytes are specialized to absorb nutrients from the lumen of the small intestine by expressing a select set of genes to maximize the uptake of nutrients. They develop from stem cells in the crypt and differentiate into mature enterocytes while moving along the crypt-villus axis. Using the Slc6a19 gene as an example, encoding the neutral amino acid transporter B(0)AT1, we studied regulation of the gene by transcription factors and epigenetic factors in the intestine. To investigate this question, we used a fractionation method to separate mature enterocytes from crypt cells and analyzed gene expression. Transcription factors HNF1a and HNF4a activate transcription of the Slc6a19 gene in villus enterocytes, whereas high levels of SOX9 repress expression in the crypts. CpG dinucleotides in the proximal promoter were highly methylated in the crypt and fully de-methylated in the villus. Furthermore, histone modification H3K27Ac, indicating an active promoter, was prevalent in villus cells but barely detectable in crypt cells. The results suggest that Slc6a19 expression in the intestine is regulated at three different levels involving promoter methylation, histone modification, and opposing transcription factors.

Lactoferrin ameliorates prostaglandin E2-mediated inhibition of Na+-glucose cotransport in enterocytes

Various immunoinflammatory cytokines are produced during chronic intestinal inflammation, which inhibits Na(+)-glucose cotransport (SGLT1) in villus cells. Lactoferrin (Lf), abundantly present in colostrum, is a multifunctional glycoprotein that is absorbed by receptor-mediated transcytosis in humans and animals and has been shown to exert anti-inflammatory effects. Therefore, this study aimed to examine whether Lf would prevent PGE2 effect on SGLT1 for glucose absorption in enterocytes. Intestinal epithelial cells (IEC-6) were grown on transwell plates, treated with phlorizin, PGE2, AH6809, and Lf, and 3-O-methyl d-glucopyranose (OMG) uptake was measured in 10 days postconfluent. Na(+)-dependent OMG uptake, phlorizin, and immunoblotting studies established the activity and apical membrane localization of SGLT1 in IEC-6 cells. PGE2 inhibited SGLT1 in a concentration- and time-dependent manner with an inhibitory constant (Ki) of 50.0 nmol/L and that was antagonized by prostanoid receptor inhibitor, AH6809. PGE2 did not alter Na(+)/K(+)-ATPase activity. In contrast, quantitative real-time polymerase chain reaction and Western blot analyses revealed that SGLT1-specific transcripts and protein expression level were decreased 3-fold by PGE2. Furthermore, PGE2 treatment increased intracellular cyclic adenosine monophosphate (cAMP) and Ca(2+) concentrations and decreased SGLT1 expression on the apical membrane, and these effects were ameliorated by Lf. Therefore, we conclude that Lf ameliorates the PGE2 inhibition of SGLT1 most likely via the Ca(2+)- and cAMP-signaling pathways.