Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon

Umberto Laforenza, Emanuela Cova, Giulia Gastaldi, Simona Tritto, Monica Grazioli, Nicholas F La Russo, Patrick L. Splinter, Patrizia D'Adamo, Marisa Tosco, Ulderico Ventura

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Water is an essential nutrient because it must be introduced from exogenous sources to satisfy metabolic demand. Under physiologic conditions, the colon can absorb and secrete considerable amounts of water even against osmotic gradients, thus helping to maintain the body fluid balance. Here we describe studies on both aquaporin (AQP) expression and function using cells isolated from the superficial and lower crypt regions of the rat proximal colon. The expression of AQP-3, -4, and -8 in isolated colonocytes was determined by semiquantitative RT-PCR and by immunoblotting. The localization of AQP-8 in the colon was evaluated by immunohistochemistry. A stopped-flow light scattering method was used to examine osmotic water movement in isolated colonocytes. Moreover, the contribution of AQP-8 to overall water movement through isolated colonocytes was studied using RNA interference technology. Colonocytes from the proximal colon express AQP-3, -4, and -8 with increasing concentrations from the lower crypt cells toward those on the surface. Osmotic water permeability was higher in surface than in crypt colonocytes (P < 0.05); it was significantly inhibited by the water channel blocker dimethyl sulfoxide, and reversed by β-mercaptoethanol (P < 0.05). Immunohistochemistry revealed a strong AQP-8 labeling in the apical membrane of the superficial colonocytes. Inhibition of aquaporin-8 expression by small interfering RNA significantly decreased osmotic water permeability (∼38%; P < 0.05). Current results indicate that aquaporin-8 may play a major role in water movement through the colon by acting on the apical side of the superficial cells.

Original languageEnglish (US)
Pages (from-to)2329-2336
Number of pages8
JournalJournal of Nutrition
Volume135
Issue number10
StatePublished - Oct 2005

Fingerprint

aquaporins
colon
Colon
Water Movements
Aquaporin 3
Water
Aquaporin 4
rats
Aquaporins
water
Permeability
Immunohistochemistry
Water-Electrolyte Balance
Mercaptoethanol
immunohistochemistry
Body Fluids
permeability
RNA Interference
Dimethyl Sulfoxide
Immunoblotting

Keywords

  • Aquaporins
  • Colon
  • Small interfering RNA
  • Water channel

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

Laforenza, U., Cova, E., Gastaldi, G., Tritto, S., Grazioli, M., La Russo, N. F., ... Ventura, U. (2005). Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon. Journal of Nutrition, 135(10), 2329-2336.

Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon. / Laforenza, Umberto; Cova, Emanuela; Gastaldi, Giulia; Tritto, Simona; Grazioli, Monica; La Russo, Nicholas F; Splinter, Patrick L.; D'Adamo, Patrizia; Tosco, Marisa; Ventura, Ulderico.

In: Journal of Nutrition, Vol. 135, No. 10, 10.2005, p. 2329-2336.

Research output: Contribution to journalArticle

Laforenza, U, Cova, E, Gastaldi, G, Tritto, S, Grazioli, M, La Russo, NF, Splinter, PL, D'Adamo, P, Tosco, M & Ventura, U 2005, 'Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon', Journal of Nutrition, vol. 135, no. 10, pp. 2329-2336.
Laforenza U, Cova E, Gastaldi G, Tritto S, Grazioli M, La Russo NF et al. Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon. Journal of Nutrition. 2005 Oct;135(10):2329-2336.
Laforenza, Umberto ; Cova, Emanuela ; Gastaldi, Giulia ; Tritto, Simona ; Grazioli, Monica ; La Russo, Nicholas F ; Splinter, Patrick L. ; D'Adamo, Patrizia ; Tosco, Marisa ; Ventura, Ulderico. / Aquaporin-8 is involved in water transport in isolated superficial colonocytes from rat proximal colon. In: Journal of Nutrition. 2005 ; Vol. 135, No. 10. pp. 2329-2336.
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