Dataset Information

Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action.

ABSTRACT: Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl- channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel's proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation.

SUBMITTER: Catalan MA

PROVIDER: S-EPMC7464869 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action.

Catalán Marcelo A MA Julio-Kalajzić Francisca F Niemeyer María Isabel MI Cid Luis Pablo LP Sepúlveda Francisco V FV

Cells 20200726 8

Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl<sup>-</sup> channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole c ...[more]

PMID: 32722648

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Project description:Previous studies have reported the mechanisms of ion absorption and secretion by diverse membrane transport proteins in gills of various teleostean species. To date, however, the chloride channel expressed in the basolateral membrane of mitochondrion-rich (MR) cells for Cl(-) uptake in freshwater (FW) fish is still unknown. In this study, the combination of bioinformatics tools [i.e. National Center for Biotechnology Information (NCBI) database, Tetraodon nigroviridis (spotted green pufferfish) genome database (Genoscope), BLAT and BLASTn] were used to identify the gene of ClC-3 (TnClC-3), a member of the CLC chloride channel family in the T. nigroviridis genome. RT-PCR analysis revealed that the gene encoding for the ClC-3 protein was widely expressed in diverse tissues (i.e. gill, kidney, intestine, liver and brain) of FW- and seawater (SW)-acclimated pufferfish. In whole-mount double immunofluorescent staining, branchial ClC-3-like immunoreactive protein was localized to the basolateral membrane of Na(+)/K(+)-ATPase (NKA) immunoreactive cells in both the FW- and SW-acclimated pufferfish. In response to salinity, the levels of transcript of branchial TnClC-3 were similar between FW and SW fish. Moreover, the membrane fraction of ClC-3-like protein in gills was 2.7-fold higher in FW compared with SW pufferfish. To identify whether the expression of branchial ClC-3-like protein specifically responded to lower environmental [Cl(-)], the pufferfish were acclimated to artificial waters either with a normal (control) or lower Cl(-) concentration (low-Cl). Immunoblotting of membrane fractions of gill ClC-3-like protein showed the expression was about 4.3-fold higher in pufferfish acclimated to the low-Cl environment than in the control group. Furthermore, branchial ClC-3-like protein was rapidly elevated in response to acute changes of environmental salinity or [Cl(-)]. Taken together, pufferfish ClC-3-like protein was expressed in the basolateral membrane of gill MR cells, and the protein amounts were stimulated by hyposmotic and low-Cl environments. The enhancement of ClC-3-like protein may trigger the step of basolateral Cl(-) absorption of the epithelium to carry out iono- and osmoregulatory functions of euryhaline pufferfish gills.

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Dataset Information

Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action.

Publications

Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action.

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