Identification and characterization of a Kidd antigen/UT-B urea transporter expressed in human colon

Inoue, Hideki; Jackson, Shelley D.; Vikulina, Tatyana; Klein, Janet D.; Tomita, Kimio; Bagnasco, Serena M.

doi:10.1152/ajpcell.00443.2003

Cited by 55 publications

(56 citation statements)

References 31 publications

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“…8A). The bands of 50 and 98 kDa in rumen epithelium are similar in size to the UT-B protein bands previously detected in rat and human colon (24). The detected signals in the rat testis (Fig.…”

Section: Ut-b Expression In Rumen Epitheliumsupporting

confidence: 81%

Short-chain fatty acids and acidic pH upregulate UT-B, GPR41, and GPR4 in rumen epithelial cells of goats

Gui

Yao

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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Currently, the mechanism(s) responsible for the regulation of urea transporter B (UT-B) expression levels in the epithelium of the rumen remain unclear. We hypothesized that rumen fermentation products affect ruminal UT-B expression. Therefore, the effects of short-chain fatty acids (SCFA), pH, ammonia, and urea on mRNA and protein levels of UT-B were assayed in primary rumen epithelial cell cultures and in rumen epithelium obtained from intact goats. In vitro, SCFA and acidic pH were found to synergetically stimulate both mRNA and protein expression of UT-B, whereas NH 4Cl decreased mRNA and protein levels of UT-B at pH 6.8. Treatment with urea increased both levels at pH 7.4. When goats received a diet rich in nitrogen (N) and nonfiber carbohydrates (NFC), their rumen epithelium had higher levels of UT-B, and the rumen contained higher concentrations of SCFA and NH 3-N with a lower pH. An increase in plasma urea-N concentration was also observed compared with the plasma of the goats that received a diet low in N and NFC. In a second feeding trial, goats that received a NFC-rich, but isonitrogenous, diet had higher mRNA and protein levels of UT-B, and higher levels of G proteincoupled receptor (GPR) 41 and GPR4, in their rumen epithelium. The ruminal concentrations of SCFA and NH 3-N also increased, while a lower pH was detected. In contrast, the serum urea-N concentrations remained unchanged. These data indicate that ruminal SCFA and pH are key factors, via GPR4 and GPR41, in the dietary regulation of UT-B expression, and they have priority over changes in plasma urea.SCFA and pH; UT-B expression; GPR41; GPR4; rumen epithelial cells; diet RECYCLING OF UREA TO THE MAMMALIAN gut accounts for 20 -30% of liver-synthesized urea that is present in humans (17). In contrast, these levels vary from 10 to 90% in ruminants (21) with feeding strategy (21) and intake of fermentable carbohydrates (22). These characteristics make the ruminant forestomach, especially the rumen, an excellent model for studies of urea entry and regulation in the gut. Urea transport across the rumen epithelium is generally accepted to occur down a concentration gradient from blood to lumen by diffusion through transport proteins, such as urea transporter B (UT-B), or possibly aquaporins. In our laboratory's recent studies, rumen fermentation products, including short-chain fatty acids (SCFA) and ammonia, as well as pH, were found to rapidly modulate UT-B activity (1, 34). It is possible that multiple mechanisms mediate regulation of urea transport, although these mechanisms are not fully characterized. UT-B has been found in many tissues and species, including human and rodent colon tissues, in erythrocytes and kidney tissue, as well as in ovine and bovine rumen (52). In bovine tissues, the UT-B protein exists as a multimer (30). Previous studies (21, 39, 41) have shown that changes in dietary nitrogen (N) content causes significant changes in serum urea-N (BUN) concentrations and the entry of urea into the gut. However, a correlation between N ...

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Section: Ut-b Expression In Rumen Epitheliumsupporting

confidence: 81%

Short-chain fatty acids and acidic pH upregulate UT-B, GPR41, and GPR4 in rumen epithelial cells of goats

Gui

Yao

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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“…UT-A1 in the colon (You et al, 1993) and UT-B (Inoue et al, 2004) and UT-A6 (Smith et al, 2004) both in the small intestine and the colon. It is assumed that urea transport into the colon is facilitated and that the hydrolysis and salvage of nitrogen from hydrolysed urea is regulated by protein intake and need (Jackson, 1998).…”

Section: Faecesmentioning

confidence: 99%

“…It is assumed that urea transport into the colon is facilitated and that the hydrolysis and salvage of nitrogen from hydrolysed urea is regulated by protein intake and need (Jackson, 1998). However, the UT-B from human colon was demonstrated to stimulate urea transport in both directions (Inoue et al, 2004). In rats protein abundance of UT-B in the colon was reduced on a low-protein diet both with and without supplementation of urea (Inoue et al, 2005).…”

Section: Faecesmentioning

confidence: 99%

Scientific Opinion on Dietary Reference Values for water

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2010

EFS2

331

114

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This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) deals with the setting of dietary reference values for water for specific age groups. Adequate Intakes (AI) have been defined derived from a combination of observed intakes in population groups with desirable osmolarity values of urine and desirable water volumes per energy unit consumed. The reference values for total water intake include water from drinking water, beverages of all kind, and from food moisture and only apply to conditions of moderate environmental temperature and moderate physical activity levels (PAL 1.6). AIs for infants in the first half of the first year of life are estimated to be 100-190 mL/kg per day. For infants 6-12 months of age a total water intake of 800-1000 mL/day is considered adequate. For the second year of life an adequate total water intake of 1100-1200 mL/day is defined by interpolation, as intake data are not available. AIs of water for children are estimated to be 1300 mL/day for boys and girls 2-3 years of age; 1600 mL/day for boys and girls 4-8 years of age; 2100 mL/day for boys 9-13 years of age; 1900 mL/day for girls 9-13 years of age. Adolescents of 14 years and older are considered as adults with respect to adequate water intake. Available data for adults permit the definition of AIs as 2.0 L/day (P 95 3.1 L) for females and 2.5 L/day (P95 4.0 L) for males. The same AIs as for adults are defined for the elderly. For pregnant women the same water intake as in non-pregnant women plus an increase in proportion to the increase in energy intake (300 mL/day) is proposed. For lactating women adequate water intakes of about 700 mL/day above the AIs of non-lactating women of the same age are derived. KEY WORDSWater, total body water, hydration, osmolarity, water balance, regulation, distribution, consumption, water loss, water requirement, adequate intake SUMMARYFollowing a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a scientific Opinion on Population Reference Intakes.Water is consumed from different sources, which include drinking water (tap and bottled water), beverages, moisture content of foods, and water produced by oxidative processes in the body. Water intake from beverages and foods is defined as total water intake, while the sum of total water intake and oxidation water constitutes total available water.Water is essential for practically all functions of the body and is particularly important for thermoregulation.A water intake which balances losses and thereby assures adequate hydration of body tissues is essential for health and life.The water content of the body and the distribution of body water over the intracellular and extracellular compartments of the body changes with age, but is under tight homeostatic control for an individual in a given stage of life.Loss of body weight, denoting loss of body water, of about 1% is normally compensated within 24 hours. Without compensation and furthe...

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“…The Papp u and Papp m values through the small pathway were calculated as the difference between the observed and calculated values for each monolayer, although a contribution of UT-B urea transporter to the transport of urea through Caco-2 cell monolayers has been reported. 16) The e/L and R of the small pathway for samples 13-1 and -2 were calculated using the Renkin function. When the calculated Papp u through the small pathway was compared with the observed total Papp u for each monolayer, the contribution of the small pore pathway to urea permeation was over 80% if the contribution of the UT-B urea transporter is negligible, suggesting that the small pathway is the major permeation pathway for such small hydrophilic molecules.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the Establishment of a Tight Junction in Caco-2 Cell Monolayers Using a Pore Permeation Model Involving Two Different Sizes

Seki

Harada

Hosoya

et al. 2008

Biological & Pharmaceutical Bulletin

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The tight junction formation in Caco-2 cell monolayers was compared after 9 and 13 d of culture. Four different sized paracellular markers were simultaneously applied to the apical side of the monolayers. The transepithelial resistance and permeability coefficient of mannitol for the monolayers cultured for 13 d were 17.4 and 0.095 times those after 9 d, respectively. The tight junction structure developed during that period. The pore permeation model involving two different sizes was used to quantitatively evaluate the paracellular pathways. The results suggest that there were two-different sized (large and small) pathways in the monolayers cultured for 13 d, while there was only a single large pathway in those cultured for 9 d. The small pathway in the monolayers cultured for 13 d might be a major permeation pathway for the paracellular permeation of urea and the equivalent cylindrical pore radius of the small pathway was less than 0.4 nm, suggesting development of the tight junctions after 13 d.

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Identification and characterization of a Kidd antigen/UT-B urea transporter expressed in human colon

Cited by 55 publications

References 31 publications

Short-chain fatty acids and acidic pH upregulate UT-B, GPR41, and GPR4 in rumen epithelial cells of goats

Short-chain fatty acids and acidic pH upregulate UT-B, GPR41, and GPR4 in rumen epithelial cells of goats

Scientific Opinion on Dietary Reference Values for water

Evaluation of the Establishment of a Tight Junction in Caco-2 Cell Monolayers Using a Pore Permeation Model Involving Two Different Sizes

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