Disease relevance of Cldn7

• Interestingly, 82% of human intestinal-type gastric adenocarcinomas expressed Cldn7 whereas diffuse-type gastric adenocarcinomas did not (P < 0.001) [1].
• Cldn7 expression was observed in 30% of metaplasia, 80% of dysplasia, and 70% of gastric adenocarcinomas [1].
• One member of this family, claudin 7, has been shown to be expressed in the human mammary epithelium and some breast tumors [2].

High impact information on Cldn7

• Importantly, this epithelial DC population expressed high levels of the Langerhans cell marker Langerin and the tight junction proteins Claudin-1, Claudin-7, and ZO-2 [3].
• Using immunohistochemistry, both mouse and human gastric glands overexpressed Cldn7 in dysplastic but not surrounding normal glands [1].
• Expression of tight-junction protein claudin-7 is an early event in gastric tumorigenesis [1].
• However, transepithelial electrical resistance in claudin-7-overexpressing cells was greatly increased [4].
• Taken together, our studies demonstrated for the first time that the effect of claudin-7 overexpression in LLC-PK1 cells on paracellular transport is mediated through a concurrent decrease in the paracellular conductance to Cl(-) and an increase in the paracellular conductance to Na(+) [4].

Biological context of Cldn7

• Induced expression of HNF-4alpha led to translocation of these tight-junction and cell polarity proteins to beltlike tight junctions, where occludin, claudin-6 and claudin-7 were assembled, in differentiated cells [5].

Anatomical context of Cldn7

• Claudin-7, -8, -12, -13, and -15 appeared to be expressed in the duodenum, jejunum, ileum, and/or colon with remarkable variations in the expression levels along the intestinal tract, and had distinct subcellular localization in the intestinal epithelium [6].
• To set the stage for functional experiments on this molecule, we examined the developmental expression and localization of claudin 7 in the murine mammary epithelium and in a selection of murine mammary tumors [2].
• Claudin 7 expression and localization in the normal murine mammary gland and murine mammary tumors [2].
• These observations suggest that claudin 7 might be involved in vesicle trafficking to the basolateral membrane, possibly stabilizing cytoplasmic vesicles or participating in cell-matrix interactions [2].
• We examined the expression and distribution of claudin-1 to claudin-18 (except for claudin-7, -13 and -17) in the inner ear by immunofluorescence microscopy [7].

Associations of Cldn7 with chemical compounds

• Expression of claudin-7 and -8 along the mouse nephron [8].
• When NaCl was replaced with sodium aspartate, transepithelial electrical resistance was significantly decreased and dilution potentials were increased in claudin-7-overexpressing cells as compared to controls, the opposite effects from that of using NaCl [4].

Other interactions of Cldn7

• By contrast, claudin-7 was found in the same nephron segments as claudin-8, but it was expressed primarily at the basolateral membrane [8].

Analytical, diagnostic and therapeutic context of Cldn7

• To determine the nephron segment localization of claudin-7 and -8, immunofluorescence staining of mouse kidney sections was performed using isoform-specific antibodies [8].

References