Impaired E-cadherin expression in human spermatozoa in a male factor infertility subset signifies E-cadherin-mediated adhesion mechanisms operative in sperm–oolemma interactions

The effects of sesame oil and different doses of estradiol on testicular structure, sperm parameters, and chromatin integrity in old mice

Objective

Studies of the effects of estrogens on the male reproductive system have emphasized the role of these hormones in male fertility. Sesame oil has many phytoestrogenic compounds and may improve male fertility. This study investigated the effects of sesame oil and different concentrations of estrogen on sperm parameters and DNA integrity in male mice.

Methods

Twenty old NMRI (The Naval Medical Research Institute) male mice (40 weeks; weight, 30–35 g) were treated with sesame oil or different concentrations of estrogen (estradiol, 1 and 10 μL/kg/day) or received no treatment (controls). After 35 days, sperm parameters and DNA integrity were assessed and analyzed.

Results

Sperm count, progressive motility, and morphology were decreased in the group that received 10 μL/kg of estradiol. A remarkably lower percentage of DNA fragmentation and protamine deficiency were detected in the group that received 1 μL/kg of estradiol. In the groups that received sesame oil and 1 μL/kg of estradiol, the numbers of spermatogonia and Leydig cells were higher than in controls. The combination of sesame oil and 1 μL/kg of estradiol led to improved sperm parameters and chromatin and testicular structure.

Conclusion

Based on this study, consumption of sesame oil and a low concentration of estradiol may improve testicular function in older mice.

Functional variations of NFKB1 and NFKB1A in inflammatory disorders and their implication for therapeutic approaches

Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) is a sophisticated transcription factor that is particularly important in the inflammatory response, but it regulates more than 400 individual and dependent genes for parts of the apoptotic, angiogenic, and proliferative, differentiative, and cell adhesion pathways. NF-κB function is directly inhibited by the binding of inhibitor of κB (IκB), and the imbalance between NF-κB and IκB has been linked to the development and progression of cancer and a variety of inflammatory disorders. These observations might broaden the horizon of current knowledge, particularly on the pathogenesis of inflammatory diseases considering the roles of NF-κB and IκB. In this context, we focus this narrative review on a comparative discussion of our findings with other literature regarding variations of NFKB1 and NFKB1A and their association with susceptibility to widespread inflammatory disorders (such as atherosclerosis, morbid obesity, Behçet syndrome, Graves disease, Hashimoto disease) and common cancers (such as gliomas).

Cadherin mutation linked to resistance to Cry1Ac affects male paternity and sperm competition in Helicoverpa armigera

Several lepidopteran pests of cotton have cadherin-based resistance to the Bacillus thuringiensis (Bt) toxin Cry1Ac. Cadherins are transmembrane proteins that mediate cell-cell adhesion and tissue morphogenesis, suggesting that fitness costs associated with cadherin mutations may be present in many aspects of life history. To evaluate whether cadherin-based resistance is associated with fitness costs reducing male paternity in Helicoverpa armigera, we examined the effects of a major cadherin resistance allele on sperm competition within and between male ejaculates. When homozygous resistant and susceptible males competed for fertilization of a homozygous resistant or susceptible female, fertilization success was high in males with a different cadherin genotype than females, and low in males with the same cadherin genotype as females. Single matings between heterozygous males and susceptible females produced offspring within typical Mendelian ratios. Heterozygous males mated to resistant females, however, resulted in a disproportionate number of heterozygous offspring. While these results show that cadherin-based resistance to Cry1Ac has significant impacts on paternity in H. armigera, there was no evidence that costs associated with resistance consistently reduced male paternity. Rather, effects of cadherin-based resistance on paternity depended on interactions between male and female genotypes and differed when males or sperm competed for fertilization of females, which complicates assessment of impacts of cadherin resistance alleles on resistance evolution.

Cadherin gene expression and effects of Bt resistance on sperm transfer in pink bollworm

Cadherin proteins bind Bacillus thuringiensis (Bt) toxins in lepidopteran midguts but their inherent function remains unclear. In pink bollworm, Pectinophora gossypiella, three recessive mutations in a cadherin gene (BtR) are tightly linked with resistance to Bt toxin Cry1Ac. Here we examined patterns of transcription of this gene and the association between cadherin genotype and sperm transfer in pink bollworm. Cadherin RNA was most abundant in larvae, but was also found in adults and embryos. In fourth instar larvae, cadherin RNA was most abundant in the gut, yet its presence in the testes indicates a potential role in sperm production. Previously, we found reduced first-male paternity in pink bollworm males homozygous for cadherin mutations conferring resistance to Bt, when a resistant and susceptible male competed for access to a female. However, the number of offspring sired by resistant and susceptible males was similar without competition. Male Lepidoptera produce both fertile eupyrene sperm and anucleate, non-fertile apyrene sperm, suggesting that apyrene sperm may contribute to male reproductive success when sperm competition occurs. Accordingly, we hypothesized that cadherin-based resistance to Bt entails fitness costs that reduce apyrene sperm transfer. To test this hypothesis, we compared apyrene and eupyrene sperm transfer in males from four strains of pink bollworm. Transfer of apyrene and eupyrene sperm was lower in homozygous resistant than in susceptible males. Furthermore, homozygous resistant males weighed less than susceptible males, which could have diminished sperm transfer by resistant males directly, or via a positive association between male weight, spermatophore weight and sperm transfer. While data suggest that cadherin mutations induced a recessive fitness cost affecting apyrene sperm transfer, these mutations also generated recessive costs that affected other traits and could have lowered first-male paternity.

Expression of epithelial cadherin in the human male reproductive tract and gametes and evidence of its participation in fertilization

Epithelial cadherin (E-cadherin) has been involved in several calcium-dependent cell-cell adhesion events; however, its participation in gamete interaction has not been fully investigated. Our results have demonstrated expression of E-cadherin mRNA in the human male reproductive tract showing higher levels in the caput, corpus and cauda epididymis than in the testis. The mature 122 kDa E-cadherin was detected in epididymal protein extracts and was localized in the epithelial cells from the three epididymal regions. Moreover, the 86 kDa E-cadherin ectodomain was found in cauda epididymal and seminal plasma. Western immunoblotting of human sperm protein extracts allowed the identification of four E-cadherin forms (122, 105, 97 and 86 kDa). The protein was localized in the acrosomal region of intact spermatozoa, remained associated with the head of acrosome-reacted cells and was also detected on the oocyte surface. A similar localization was determined for other proteins of the adhesion complex (beta-catenin and actin). Spermatozoa incubated with anti-E-cadherin antibodies showed impaired binding to homologous zona pellucida (ZP); in addition, presence of these antibodies inhibited the penetration of human spermatozoa to ZP-free hamster oocytes. The results presented here describe the expression of E-cadherin in the male reproductive tract and gametes and strongly suggest its involvement in adhesion events during human fertilization. The identification of proteins involved in gamete interaction will contribute to the understanding of the molecular basis of fertilization and help in the diagnosis and treatment of infertility.