Role of mitochondria‐rich cells in epithelial chloride uptake

Larsen, Erik Hviid; Christoffersen, BC; Jensen, Lars Jørn; Sørensen, Jonas; Willumsen, NJ

doi:10.1113/expphysiol.1996.sp003955

Cited by 17 publications

(12 citation statements)

References 15 publications

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“…Ϫ exchanger in frog skin (11,23). A similar mechanism has been proposed in gills of freshwater fishes (7,27,29); however, the exact sites for H ϩ secretion are still a controversial subject (see introduction).…”

Section: Discussionmentioning

confidence: 80%

Proton pump-rich cell secretes acid in skin of zebrafish larvae

Li¹,

Horng²,

Kunkel³

et al. 2006

American Journal of Physiology-Cell Physiology

184

203

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The mammalian kidney excretes its metabolic acid load through the proton-transporting cells, intercalated cells, in the distal nephron and collecting duct. Fish excrete acid through external organs, gill, or skin; however, the cellular function is still controversial. In this study, molecular and electrophysiological approaches were used to identify a novel cell type secreting acid in skin of zebrafish (Danio rerio) larvae. Among keratinocytes covering the larval surface, novel proton-secreting ionocytes, proton pump (H(+)-ATPase)-rich cells, were identified to generate strong outward H(+) flux. The present work demonstrates for the first time, with a noninvasive technique, H(+)-secreting cells in an intact animal model, the zebrafish, showing it to be a suitable model in which to study the functions of vertebrate transporting epithelia in vivo.

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Section: Discussionmentioning

confidence: 80%

Proton pump-rich cell secretes acid in skin of zebrafish larvae

Li¹,

Horng²,

Kunkel³

et al. 2006

American Journal of Physiology-Cell Physiology

184

203

View full text Add to dashboard Cite

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“…These studies have identified cells that have been proposed to be analogous to ICs in the kidney, based on the fact that they independently exchange Na + for H + and Cl -for HCO 3 - (Larsen et al, 1996;Ehrenfeld and Klein, 1997;Jensen et al, 2003), using a proton-motive force attributed to a H + v-ATPase pump related to that in mammalian ICs Jensen et al, 2002). Here, we provide evidence that cells remarkably similar to the ICs of the mammalian kidney arise in the Xenopus larval skin.…”

Section: Discussionmentioning

confidence: 99%

Specification of ion transport cells in theXenopuslarval skin

2011

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SUMMARYSpecialized epithelial cells in the amphibian skin play important roles in ion transport, but how they arise developmentally is largely unknown. Here we show that proton-secreting cells (PSCs) differentiate in the X. laevis larval skin soon after gastrulation, based on the expression of a 'kidney-specific' form of the H + v-ATPase that localizes to the plasma membrane, orthologs of the Cl -/HCO 3 -antiporters ae1 and pendrin, and two isoforms of carbonic anhydrase. Like PSCs in other species, we show that the expression of these genes is likely to be driven by an ortholog of foxi1, which is also sufficient to promote the formation of PSC precursors. Strikingly, the PSCs form in the skin as two distinct subtypes that resemble the alpha-and beta-intercalated cells of the kidney. The alpha-subtype expresses ae1 and localizes H + v-ATPases to the apical plasma membrane, whereas the beta-subtype expresses pendrin and localizes the H + v-ATPase cytosolically or basolaterally. These two subtypes are specified during early PSC differentiation by a binary switch that can be regulated by Notch signaling and by the expression of ubp1, a transcription factor of the grainyhead family. These results have implications for how PSCs are specified in vertebrates and become functionally heterogeneous.

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“…Since fluid secreted into the tubule lumen is not sufficiently acidic to drive cation/H + antiport, the pH of an unstirred layer in the brush border might be low enough, as in amphibian skin (Larsen et al, 1996). In addition, large negative surface charges of the apical membrane due to fixed negative charges of glycosylated proteins, glycolipids and adsorbed proteins may support a surface pH considerably lower than that in the aqueous solution of the tubule lumen (Aronson and Giebisch, 1997).…”

Section: Atpase Activitiesmentioning

confidence: 99%

The V-type H+-ATPase in Malpighian tubules of Aedes aegypti: localization and activity

Weng

Huss

Wieczorek

et al. 2003

Journal of Experimental Biology

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SUMMARY The V-type H+-ATPase is thought to provide the driving force for transepithelial electrolyte and fluid secretion in Malpighian tubules. To confirm the presence of this proton pump in Malpighian tubules of the yellow fever mosquito Aedes aegypti, we used several antibodies raised against the V-type H+-ATPase of Manduca sexta. Western blot analysis confirmed the presence of the V-type H+-ATPase in Malpighian tubules of Aedes aegypti. In situ immunostaining identified the V-type H+-ATPase at the apical membrane of the mitochondrion-rich brush border of principal cells. The V-type H+-ATPase was not found in stellate cells. Measurements of ATPase activity revealed that bafilomycin-sensitive and NO3--sensitive ATPase activity accounted for 50–60% of total ATPase activity in crude extracts of Malpighian tubules. No significant ouabain- or vanadate-sensitive Na+/K+-ATPase activity was detected. These results support the conclusion reached previously in electrophysiological studies that the mechanisms for transepithelial electrolyte secretion in the AedesMalpighian tubules rely on the V-type H+-ATPase as the principal energizer of epithelial transport. Measures of transepithelial Na+and K+ secretion and estimates of the H+ flux mediated by the V-type H+-ATPase suggest a 1:1 stoichiometry for Na+/H+ and K+/H+ exchange transport across the apical membrane.

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Role of mitochondria‐rich cells in epithelial chloride uptake

Cited by 17 publications

References 15 publications

Proton pump-rich cell secretes acid in skin of zebrafish larvae

Proton pump-rich cell secretes acid in skin of zebrafish larvae

Specification of ion transport cells in theXenopuslarval skin

The V-type H+-ATPase in Malpighian tubules of Aedes aegypti: localization and activity

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