Intestinal Anion Exchanger Down-regulated in Adenoma (DRA) Is Inhibited by Intracellular Calcium

Lamprecht, Georg; Hsieh, Chih-Jen; Lissner, Simone; Nold, Lilia; Heil, Andreas; Gaco, Vera; Schäfer, Julia; Turner, Jerrold R.; Gregor, Michael

doi:10.1074/jbc.m109.004127

Cited by 33 publications

(43 citation statements)

References 44 publications

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“…It was shown previously that the Cl -/HCO 3 -exchanger SLC26A3 and NHE3 are inhibited by the pathological increase of intracellular Ca 2+ [6,26]. In our experiments, CDC induced a dose- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 the release from the ER via IP 3 R and/or RyR or Ca 2+ entry from the extracellular space [32,14,13] [26].…”

Section: Discussionmentioning

confidence: 96%

Bile acids inhibit Na+/H+ exchanger and Cl−/HCO3 − exchanger activities via cellular energy breakdown and Ca2+ overload in human colonic crypts

Pallagi-Kunstár

Farkas

Maléth

et al. 2014

Pflugers Arch - Eur J Physiol

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Abstract:Bile acids play important physiological role in the solubilisation and absorption of dietary lipids. However, under pathophysiological conditions, such as short bowel syndrome, they can reach the colon in high concentrations inducing diarrhea. In this study our aim was to characterise the cellular pathomechanism of bile-induced diarrhea using human samples. Colonic crypts were isolated from biopsies of patients (controls with negative colonoscopic findings) and of cholecystectomised/ileumresected patients with or without diarrhoea. In vitro measurement of the transporter activities revealed impaired Na+/H+ exchanger (NHE) and Cl-/HCO3-exchanger (CBE) activities in cholecystectomised/ileum-resected patients suffering from diarrhea, compared to control patients. Acute treatment of colonic crypts with 0.3mM chenodeoxycholate caused dose-dependent intracellular acidosis; moreover, the activities of acid/base transporters (NHE and CBE) were strongly impaired. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 3 AbstractBile acids play important physiological role in the solubilisation and absorption of dietary lipids. However, under pathophysiological conditions, such as short bowel syndrome, they can reach the colon in high concentrations inducing diarrhea. In this study our aim was to characterise the cellular pathomechanism of bile-induced diarrhea using human samples. Colonic crypts were isolated from biopsies of patients (controls with negative colonoscopic findings) and of cholecystectomised/ileum-resected patients with or without diarrhoea. In vitro measurement of the transporter activities revealed impaired Na + /H + exchanger (NHE) and Cl -/HCO 3 -exchanger (CBE) activities in cholecystectomised/ileum-resected patients suffering from diarrhea, compared to control patients. Acute treatment of colonic crypts with 0.3mM chenodeoxycholate caused dose-dependent intracellular acidosis; moreover, the activities of acid/base transporters (NHE and CBE) were strongly impaired. This concentration of chenodeoxycholate did not cause morphological changes in colonic epithelial cells, although significantly reduced the intracellular ATP level, decreased mitochondrial transmembrane potential and caused sustained intracellular Ca 2+ elevation. We also showed that chenodeoxycholate induced Ca 2+ release from the endoplasmic reticulum and extracellular Ca 2+ influx contributing to the Ca 2+ elevation. Importantly, our results suggest that the chenodeoxycholate induced inhibition of NHE activities was ATP-dependent, whereas the inhibition of CBE activity was mediated by the sustained Ca 2+ elevation.We suggest that bile acids inhibit the function of ion transporters via cellular energy breakdown and Ca 2+ overload in human colonic epithelial cells, which can reduce fluid and electrolyte absorption in the colon and promote ...

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Section: Discussionmentioning

confidence: 96%

Bile acids inhibit Na+/H+ exchanger and Cl−/HCO3 − exchanger activities via cellular energy breakdown and Ca2+ overload in human colonic crypts

Pallagi-Kunstár

Farkas

Maléth

et al. 2014

Pflugers Arch - Eur J Physiol

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“…HEK293 cells stably transfected with EGFP-tagged DRA (HEK/EGFP-DRA) or EGFP-tagged DRA-ETKFminus (HEK/ EGFP-DRA-ETKFminus); a DRA construct that lacks the COOHterminal PDZ interaction motif (glutamate-threonine-lysine-phenylalanine, ETKF), were used as described previously (20). Caco-2/BBE cells expressing the Tet-Off system stably transfected with EGFP-DRA and EGFP-DRA-ETKFminus were used as described previously (24). They were routinely kept in the presence of 20 ng/ml doxycycline.…”

Section: Methodsmentioning

confidence: 99%

“…EGFP-PDZK1 was used as described previously (24). Human NHERF (also known as EBP50) was amplified from the Imagenes clone IRAKp961A113 using pfu and primers that incorporate a BamHI and a XhoI site (CCTTAGGGATCCAT-GAGCGCGGACG and GGCTCGAGGGCGCTCAGAGGTTGC).…”

Section: Methodsmentioning

confidence: 99%

“…DRA activity was assessed as changes in the intracellular pH (pH i) upon removal and readdition of extracellular chloride as previously described (20,24). The pHi traces were analyzed as described previously (25).…”

Section: Methodsmentioning

confidence: 99%

“…With regard to NHE3, DRA, and their common function for intestinal NaCl absorption the potential interplay of their raft association and their PDZ interaction has not been studied. To this end DRA has the advantage that a mutant, which lacks the PDZ interaction motif (DRA-ETKFminus), can be expressed and is functionally active (24).…”

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confidence: 99%

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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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Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease

Seidler

Nikolovska

2019

Comprehensive Physiology

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SLC26 family members are multifunctional transporters of small anions, including Cl − , HCO 3 − , sulfate, oxalate, and formate. Most SLC26 isoforms act as secondary (coupled) anion transporters, while others mediate uncoupled electrogenic transport resembling Cl − channels. Of the 11 described SLC26 isoforms, the SLC26A1,2,3,6,7,9,11 are expressed in the gastrointestinal tract, where they participate in salt and water transport, surface pH‐microclimate regulation, affect the microbiome composition, the absorption, and secretion of oxalate and sulfate, and other functions that require further study. Several intestinal or extra‐intestinal diseases are related to SLC26A mutations. Patients with congenital chloride diarrhea (CLD) suffer from Cl − ‐rich acidic diarrhea and systemic alkalosis due to SLC26A3 mutations. Patients with osteochondrodysplastic syndromes experience skeletal defects due to SLC26A2 mutations, resulting in defective sulfate absorption in enterocytes and sulfate uptake in chondrocytes. Because of functional interactions between SLC26 and other proteins, such as the Cl − channel CFTR, some of the intestinal cystic fibrosis manifestations may be attributed to impaired SLC26 isoform localization and function. The altered expression of SLC26 members due to inflammation or operative procedures have important consequences on intestinal transport and barrier function in common diseases as inflammatory bowel disease or bariatric surgery. The present review gives an overview on the current state of knowledge of the intestinally expressed SLC26A isoforms (SLC26A1,2,3,6,7,9,11) from the history of their functional identification, cloning and expression, the insights into their function, interaction partners and regulation gained in heterologous expression systems and Slc26a‐deficient mice, to information about their transcriptional regulation and roles in gastrointestinal disease manifestations. © 2019 American Physiological Society. Compr Physiol 9:839‐872, 2019.

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Intestinal Anion Exchanger Down-regulated in Adenoma (DRA) Is Inhibited by Intracellular Calcium

Abstract: 2؉i in DRA regulation are unknown. Wild type DRA and a mutant lacking the PDZ interaction motif (DRA-ETKFminus) were expressed constitutively in human embryonic kidney (HEK) and inducibly in Caco-2/BBE cells. DRA-mediated Cl/HCO 3 exchange was measured as intracellular pH changes. Ca

Cited by 33 publications

References 44 publications

Bile acids inhibit Na+/H+ exchanger and Cl−/HCO3 − exchanger activities via cellular energy breakdown and Ca2+ overload in human colonic crypts

Bile acids inhibit Na+/H+ exchanger and Cl−/HCO3 − exchanger activities via cellular energy breakdown and Ca2+ overload in human colonic crypts

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

Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease

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