Fig 1.
Western Blot analysis of tight junction proteins in membrane fractions of (A) testis and (B) lung (control). For negative controls, a soluble fraction (S1) of lung was used. (A) Tight junctions in the membrane fractions of human, mouse, and rat testis with three individuals each (I-III). The vinculin loading controls correspond to the experiments presented above, respectively. The testis of human (aged 65, 77 and 31), mouse and rat contain detectable amounts of claudin-11. On the same (stripped and retreated) membrane, occludin could only be detected clearly in mouse and rat whereas human testis contains only negligible amounts. No claudin-3 was found in testis of human and rat, but in mouse. (B) Tight junctions in the membrane fractions of human, mouse and rat lung. Vinculin loading control corresponds to all experiments. No claudin-11 was detected in the lung of rat and mouse. Occludin was found in lung of human, but not in rat or mouse. Strong claudin-3 expression was found in the lung of all three species. Mouse lung cytosolic fraction was only positive for vinculin, as expected. Abbreviations: S1 soluble fraction, hu human, ms mouse, rt rat.
Fig 2.
Location of claudin-11 in human testis with normal (NSP, A-C) and impaired spermatogenesis (Hyp, D-F; MA, G-I; SGA, J-L and SCO, M-O). Patches that have contact with the basal membrane are indicated by black arrowheads. Patches that do not touch the basal membrane are indicated by white arrowheads. The scale bar (15 μm) in image (A) applies to all images in panel I.
Fig 3.
Scheme of claudin-11 expression in the seminiferous epithelium used for patch analysis.
A claudin-11 patch is defined as the claudin-11 localization pattern between two points crossing the fictive line above the spermatogonia (black arrows). In the drawing the patches are indicated by brackets, letters (a-e) and triangles. If claudin-11 is in contact with the basal membrane (a & e), the patch was evaluated as positive (filled triangles), all other types negative (b-d, white triangles).
Fig 4.
Quantitative analysis of claudin-11 localization in contact with the basal membrane in men with impaired spermatogenesis compared to normal spermatogenesis.
(A) The total number of patches per tubule as well as (B) the number of patches reaching the basal membrane differs highly significant between NSP and SCO. (C) The ratio of the total number of patches versus patches with contact to the basal membrane. The ratio is significantly higher for MA and SCO. Analysis is based on a cohort of 100 patients (NSP n = 25, Hyp n = 24, MA n = 24, SCO n = 19, and SGA n = 8). Columns represent mean values with SEM indicated. Kruskal-Wallis-test was used to calculate p-values, p ≤ 0.05 was considered significant (*), p ≤ 0.001 highly significant (**), respectively, p ≤ 0.0001 (***).