Specific Deletion of Cdh2 in Sertoli Cells Leads to Altered Meiotic Progression and Subfertility of Mice1

Abstract

CDH2 (cadherin 2, Neural-cadherin, or N-cadherin) is the predominant protein of testicular basal ectoplasmic specializations (basal ES; a testis-specific type of adhesion junction), one of the major cell junctions composing the blood-testis barrier (BTB). The BTB is found between adjacent Sertoli cells in seminiferous tubules, which divides the tubules into basal and adluminal compartments and prevents the deleterious exchange of macromolecules between blood and seminiferous tubules. However, the exact roles of basal ES protein CDH2 in BTB function and spermatogenesis is still unknown. We thus generated mice with Cdh2 specifically knocked out in Sertoli cells by crossing Cdh2 loxP mice with Amh-Cre mice. Cdh2 deletion in Sertoli cells did not affect Sertoli cell counts, but led to compromised BTB function, delayed meiotic progression from prophase to metaphase I in testes, increased germ cell apoptosis, sloughing of meiotic cells, and, subsequently, reduced sperm counts in epididymides and subfertility of mice. However, the testes with Cdh2-specific deletion in germ cells did not show any difference from the normal control testes, and phenotypes observed in Sertoli cell and germ cell Cdh2 double-knockout mice were indistinguishable from those in mice with Cdh2 specifically knocked out only in Sertoli cells. Taken together, our data demonstrate that the adhesion junction component, Cdh2, functions just in Sertoli cells, but not in germ cells during spermatogenesis, and is essential for the integrity of BTB function, its deletion in Sertoli cells would lead to the BTB damage and subsequently meiosis and spermatogenesis failure.

RPL10L Is Required for Male Meiotic Division by Compensating for RPL10 during Meiotic Sex Chromosome Inactivation in Mice

“…The percentage of Rpl10l À/À spermatocytes in each successive stage (leptotene, zygotene, pachytene, and diplotene) was comparable to those of Rpl10l +/À spermatocytes ( Figures 2B and 2C), indicating that the progression of prophase I was not affected following the deletion of Rpl10l. We next examined the progression from prophase to metaphase of meiosis I using the meiotic delay assay [23]. Testes from adult Rpl10l À/À males contained significantly fewer spermatocytes in the first meiotic metaphase (MMI) than testes from Rpl10l +/À littermates ( Figure 2D), indicating that spermatogenesis was arrested at the transition from prophase I to metaphase I.…”

“…Testis sections were prepared as described [23]. For histological analysis, testes were fixed in 4% paraformaldehyde or Bouin's fixative overnight at 4 C. Samples were dehydrated through a graded series of ethanol, embedded in paraffin, serially sectioned, and stained with hematoxylin and eosin or periodic acid-Schiff.…”

“…Meiotic preparations were made as previously described [23]. Briefly, single-cell suspensions were prepared from isolated seminiferous tubule fragments in 2.2% (w/v) trisodium citrate dihydrate (isotonic solution) and centrifuged for 10 min at 800 rpm, followed by treatment with 0.9% (w/v) trisodium citrate dihydrate (hypotonic solution) for 12 min at 37 C and fixation in Carnoy's solution (75% methanol, 25% acetic acid) at 4 C. After three washes in fixative, chromosome preparations were made by dropping the cell suspension onto cold slides.…”

Ndrg3 gene regulates DSB repair during meiosis through modulation the ERK signal pathway in the male germ cells

“…Firstly, the spermatogenesis progression analysis was performed using 8 weeks old mice. The morphologies of mid-pachytene spermatocyte, metaphase stage of spermatogonium, metaphase I and metaphase II spermatocyte were distinguished according to the previous study32 and the results were shown in Supplemental Figure 2. Based on counting the specific cell number per 1000 spermatocytes, Ndrg3 +/− mouse resulted in a significant decrease in the frequencies of meiosis I metaphase (MMI) or meiosis II metaphase (MMII) (Table 1), indicating that spermatogenesis was disturbed in Ndrg3 +/− mice.…”

“…ANOVA or Student’s t test were used for statistical comparison to determine significance. The difference of the number of spermatogonium, MMI and MMII cells as well as the ratios of MMII to MMI were tested for significance using the Mann-Whitney U -test as described previously32. Statistical significance set: NS, P > 0.05; *P ≤ 0.05; **P ≤ 0.01.…”