Modelling of electrolyte transport in renal and intestinal epithelia

Knauf, H.; Gerok, W.

doi:10.1007/bf01716722

Cited by 3 publications

(3 citation statements)

References 75 publications

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“…The pattern of expression of claudin‐2 must be associated with specific properties of the epithelium since the claudin‐2 tetraspan protein substantially increases transepithelial permeability to solutes and ions (Furuse et al, 2001; Amasheh et al, 2002). This correlates with the commonly accepted model of a leaky versus tight epithelium in the crypt versus upper compartments (Madara and Marcial, 1984) as well as proximal versus distal intestine (Knauf and Gerok, 1982). Claudin‐2 could also be involved with cell cohesion at the intestinal crypt base and participate in the establishment and maintenance of the polarity of poorly differentiated epithelial cells, by restricting the lateral diffusion of membrane proteins and lipids (Anderson and Van Itallie, 1995; Madara, 1998; Tsukita et al, 2001).…”

Section: Discussionsupporting

confidence: 86%

“…Thus, claudin expression could drive a major functional role in epithelial physiology, particularly considering the claudin‐2 pattern of expression in intestinal compartments. Studies showing the heterogeneity of intestinal epithelial permeability along the proximo‐distal axis (Knauf and Gerok, 1982; Pacha et al, 1987; Hosoya et al, 1993) suggest that claudin expression could be related to this physiological phenomenon. However, in the human, nothing is known about the pattern of expression of claudin‐2 in the intestinal epithelium.…”

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confidence: 99%

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Differential expression of claudin‐2 along the human intestine: Implication of GATA‐4 in the maintenance of claudin‐2 in differentiating cells

Escaffit

Boudreau

Beaulieu

2004

Journal Cellular Physiology

130

103

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Claudins, and particularly claudin-2, are important regulatory components of tight junction permeability. A better understanding of the involvement of claudin-2 in intestinal barrier functions requires the characterization of its distribution and regulation in the intestine. Interestingly, the claudin-2 gene promoter harbors a number of similarities to that of sucrase-isomaltase, a marker of enterocyte differentiation. We thus investigated the expression of claudin-2 in relation to the transcription factors CDX2, HNF-1alpha, and GATA-4 in the human intestine. The characterization of claudin-2 and the expression of the above transcription factors were performed by immunofluorescence, Western blot, and RT-PCR in the developing human intestinal epithelium. The functional role of CDX2, HNF-1alpha, and GATA-4 on claudin-2 regulation was also examined by ectopic expression studies in intestinal cell models. Claudin-2 was detected in both crypt and villus cells of the small intestine but restricted to undifferentiated crypt cells in the colon. CDX2 and HNF-1alpha were expressed along the entire intestine whereas GATA-4 was undetectable in the colon. Accordingly, in the colonic Caco-2 cell model, claudin-2 was found to be present only in undifferentiated cells. Like in the colonic epithelium, GATA-4 was found to be also lacking in Caco-2 cells while CDX2 and HNF-1alpha were present at significant levels. Cotransfection experiments showed that the claudin-2 promoter was activated by CDX2, HNF-1alpha, and GATA-4 in a cooperative manner. Furthermore, forced GATA-4 expression in Caco-2 cells enhances maintenance of claudin-2 expression during differentiation. These observations suggest that optimal claudin-2 expression in the gut relies on the presence of GATA-4, suggesting a role for this factor in intestinal regionalization.

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Section: Discussionsupporting

confidence: 86%

mentioning

confidence: 99%

Differential expression of claudin‐2 along the human intestine: Implication of GATA‐4 in the maintenance of claudin‐2 in differentiating cells

Escaffit

Boudreau

Beaulieu

2004

Journal Cellular Physiology

130

103

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“…Thus, as plasma glucose concentration is elevated, glucose résorp¬ tion increases Unearly until the Tm is obtained, after which any additional increase in the filtered glucose load is excreted in the urine. 8 The final form of renal glycosuria is caused by proximal tubule metabolic dysfunction. Splay may represent heterogeneity of the nephron population.5 Vol¬ ume expansion and uremia may also exaggerate the de¬ gree of splay.…”

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confidence: 99%

Angiotensin-Converting Enzyme Inhibitors and Glycosuria

Milavetz

Popovtzer²

1992

Arch Intern Med

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Renal glycosuria associated with the use of angiotensin-converting enzyme inhibitors has been previously reported in two patients. A third patient was studied who developed isolated glycosuria associated with lisinopril therapy. As in the two previously described patients, this patient had a normal serum glucose level, underlying hypertension, and onset of glycosuria between 2 and 16 weeks after initiation of therapy with an angiotensin-converting enzyme inhibitor. The patient had renal artery stenosis with elevated renin levels. Age, time until resolution of glycosuria, and a rise in serum creatinine level did not have a consistent relationship with glycosuria associated with angiotensin-converting enzyme inhibitor therapy. Since glycosuria was the only defect noted, without evidence of any other urinary solutes, angiotensin-converting enzyme inhibitors may exert an effect on the glucose-specific proximal tubule transport system.

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Kidney proximal tubule cells: Epithelial cells without EGTA-extractable annexins?

Tribolo¹,

Maroux²,

Massey-Harroche³

2000

Biochem. Cell Biol.

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The expression and the subcellular localizations of annexins I, II, IV, VI, and XIII in renal epithelial cells were investigated, using immunological techniques with specific monoclonal antibodies. Upon performing Western blotting experiments, no annexins VI and XIII were detected in kidney, whereas annexins I, II, and IV were. Immunofluorescence labelling procedure performed on thin frozen renal sections showed the presence of these three annexins along the plasma membrane of the collecting duct cells with a restricted expression of annexin I at principal cells. Annexin I was also found present in some glomerular cells. None of these annexins, however, were detected in the proximal tubular cells upon performing immunofluorescence labelling and electrophoretic analysis on an EGTA (ethylenebis(oxyethylenenitrilo)tetraacetic acid)-extractable annexin fraction prepared from freshly isolated cells. This is the first time a mammalian epithelial cell has been found to express non-typical annexin (at least partly solubilized with EGTA). However, when these cells were grown in primary culture, they were found to express annexins I, II, IV, and V. As well as being located along the basolateral membrane, annexins I and II are also present on vesicles, which suggests that these annexins may be involved in vesicular traffic under cell culture conditions.

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Modelling of electrolyte transport in renal and intestinal epithelia

Cited by 3 publications

References 75 publications

Differential expression of claudin‐2 along the human intestine: Implication of GATA‐4 in the maintenance of claudin‐2 in differentiating cells

Differential expression of claudin‐2 along the human intestine: Implication of GATA‐4 in the maintenance of claudin‐2 in differentiating cells

Angiotensin-Converting Enzyme Inhibitors and Glycosuria

Kidney proximal tubule cells: Epithelial cells without EGTA-extractable annexins?

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