Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl<sup>−</sup>/OH<sup>−</sup> exchange

Singla, Anuj; Dwivedi, Alka; Saksena, Seema; Gill, Ravinder K.; Alrefai, Waddah A.; Ramaswamy, Krishnamurthy; Dudeja, Pradeep K.

doi:10.1152/ajpgi.00345.2009

Cited by 38 publications

(32 citation statements)

References 46 publications

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“…Previous studies from our laboratory have shown the transcriptional regulation of DRA gene (2,14,39,41,43). In the present study our data show for the first time a novel regulatory pathway of down regulation of DRA by miR-494 via mechanisms involving translational repression through its interactions with the DRA mRNA 3=-UTR.…”

Section: Discussionsupporting

confidence: 70%

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Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Anbazhagan

Priyamvada

Kumar

et al. 2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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[downregulated in adenoma (DRA)] is a Cl Ϫ /HCO 3 Ϫ exchanger involved in electroneutral NaCl absorption in the mammalian intestine. Altered DRA expression levels are associated with infectious and inflammatory diarrheal diseases. Therefore, it is critical to understand the regulation of DRA expression. MicroRNAs (miRNAs) are endogenous, small RNAs that regulate protein expression via blocking the translation and/or promoting mRNA degradation. To investigate potential modulation of DRA expression by miRNA, five different in silico algorithms were used to predict the miRNAs that target DRA. Of these miRNAs, miR-494 was shown to have a highly conserved putative binding site in the DRA 3=-untranslated region (3=-UTR) compared with other DRA-targeting miRNAs in vertebrates. Transfection with pmirGLO dual luciferase vector containing DRA 3=-UTR (pmirGLO-3=-UTR DRA) resulted in a significant decrease in relative luciferase activity compared with empty vector. Cotransfection of the DRA 3=-UTR luciferase vector with a miR-494 mimic further decreased luciferase activity compared with cells transfected with negative control. The transfection of a miR-494 mimic into Caco-2 and T-84 cells significantly increased the expression of miR-494 and concomitantly decreased the DRA protein expression. Mutation of the seed sequences for miR-494 in 3=-UTR of DRA abrogated the effect of miR-494 on 3=-UTR. These data demonstrate a novel regulatory mechanism of DRA expression via miR-494 and indicate that targeting this microRNA may serve to be a potential therapeutic strategy for diarrheal diseases.

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Section: Discussionsupporting

confidence: 70%

“…Earlier studies from our group have shown the transcriptional regulation of DRA gene by various agents such as proinflammatory cytokine interferon-␥ (41), soluble factors secreted by probiotic Lactobacilus acidophilus (39) and lysophosphatidic acid (43). However, other mechanisms regulating DRA gene expression have yet to be investigated.…”

Section: /Hmentioning

confidence: 99%

Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Anbazhagan

Priyamvada

Kumar

et al. 2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…The involvement of PI3-kinase in the regulation of DRA has been shown in other studies as well. Lysophosphatidic acid and Lactobacillus acidophilus stimulate Cl/OH exchange and increase cell surface levels of DRA via a PI3-kinase-mediated mechanism (2,44). So far lipid rafts as well as PDZ interactions have not been addressed in this process.…”

Section: Discussionmentioning

confidence: 99%

Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts

Lissner

Nold

Hsieh

et al. 2010

American Journal of Physiology-Gastrointestinal and Liver Physi

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The Cl/HCO3 exchanger downregulated in adenoma (DRA) mediates electroneutral NaCl absorption in the intestine together with the apical Na/H exchanger NHE3. Lipid rafts (LR) modulate transport activity and are involved in phosphatidylinositol 3-kinase (PI3-kinase)-dependent trafficking of NHE3. Although DRA and NHE3 interact via PDZ adaptor proteins of the NHERF family, the role of LR and PDZ proteins in the regulation of DRA is unknown. We examined the association of DRA with LR using the nonionic detergent Triton X-100. DRA cofractionated with LR independently of its PDZ binding motif. Furthermore, DRA interacts with PDZK1, E3KARP, and IKEPP in LR, although their localization within lipid rafts is independent of DRA. Disruption of LR integrity resulted in the disappearance of DRA from LR, in a decrease of its surface expression and in a reduction of its activity. In HEK cells the inhibition of DRA by LR disruption was entirely dependent on the presence of the PDZ interaction motif. In addition, in Caco-2/BBE cells the inhibition by LR disruption was more pronounced in wild-type DRA than in mutated DRA (DRA-ETKFminus; lacking the PDZ binding motif)-expressing cells. Inhibition of PI3-kinase decreased the activity and the cell surface expression of wild-type DRA but not of DRA-ETKFminus; the partitioning into LR was unaffected. Furthermore, simultaneous inhibition of PI3-kinase and disruption of LR did not further decrease DRA activity and cell surface expression compared with LR disruption only. These results suggest that the activity of DRA depends on its LR association, on its PDZ interaction, and on PI3-kinase activity.

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“…2A). Both DRA and PAT-1 (putative anion transporter-1) are characterized as the apical membrane Cl Ϫ /HCO 3 Ϫ exchangers of intestinal epithelial cells that belong to the family of SLC26 anion exchangers (40). However, in contrast to its effects on DRA, S1P did not show any effect on PAT-1 mRNA levels at any given time point (Fig.…”

Section: S1p Stimulates CLmentioning

confidence: 95%

Transcriptional modulation of SLC26A3 (DRA) by sphingosine-1-phosphate

Anbazhagan

Priyamvada

Alakkam

et al. 2016

American Journal of Physiology-Gastrointestinal and Liver Physi

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Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl⁻/OH⁻ exchange

Abstract: Singla A, Dwivedi A, Saksena S, Gill RK, Alrefai WA, Ramaswamy K, Dudeja PK. Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl Ϫ /OH Ϫ exchange.

Cited by 38 publications

References 46 publications

Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts

Transcriptional modulation of SLC26A3 (DRA) by sphingosine-1-phosphate

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Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl−/OH− exchange

Abstract: Singla A, Dwivedi A, Saksena S, Gill RK, Alrefai WA, Ramaswamy K, Dudeja PK. Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl Ϫ /OH Ϫ exchange.

Cited by 38 publications

References 46 publications

Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Translational repression of SLC26A3 by miR-494 in intestinal epithelial cells

Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts

Transcriptional modulation of SLC26A3 (DRA) by sphingosine-1-phosphate

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Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl⁻/OH⁻ exchange