Expression of Rab25 is down-regulated in the foreskin of children with hypospadias

The potential mechanisms underlying phthalate-induced hypospadias: a systematic review of rodent model studies

Objectives

Maternal exposure to environmental endocrine disruptors, such as phthalates, during pregnancy is a significant risk factor for the development of hypospadias. By consolidating existing research on the mechanisms by which phthalates induce hypospadias in rodent models, this systematic review aims to organize and analyze the discovered mechanisms and their potential connections.

Methods

The study involved all articles that explored the mechanisms of phthalate-induced hypospadias using rodent models. A comprehensive search of the PubMed and Web of Science databases was conducted using the terms "hypospadias" and "phthalates" before January 20, 2024. Then, two investigators screened for studies worthy of inclusion by setting inclusion and exclusion criteria.

Results

Of the initial 326 search results, 22 were included in the subsequent analysis. Based on the commonalities among different results, the mechanisms of phthalate-induced hypospadias could be categorized into the following five groups: sex steroids-related signaling pathways (n=10), epithelial-mesenchymal transition (n=6), autophagy (n=5), apoptosis (n=4) and angiogenesis (n=2). Among these, sex steroids-related signaling pathways might serve as a central regulator among all mechanisms, and reactive oxygen species (ROS) also played an important mediating role.

Conclusion

The systematic review indicates that phthalates may initially disrupt the balance of sex steroids-related pathways, leading to abnormally elevated levels of ROS and subsequently to other functional abnormalities, ultimately resulting in the development of hypospadias. All these findings will help to improve prevention strategies during pregnancy to reduce the adverse effects of phthalates on the offspring.

Deficiency in the Rab25 gene leads to a decline in male fertility and testicular injury: Impact on the regulation of germ cell proliferation and apoptosis

BACKGROUND

Rab25 is a member of the Rab family, functioning as a regulatory molecule in intracellular transport. Although its involvement in cellular functions and disease development is well-established, its precise roles in male reproductive physiology remain elusive.

METHODS

To explore the specific roles of Rab25 in testicular development and spermatogenesis, we established the Rab25-/- mouse model and Rab25 knockdown germ cell line (GC-2). We compared the fertility, sperm analysis, and testicular tissues between Rab25-/- and wild-type male mice. To delve deeper into potential mechanisms, we employed immunohistochemistry, TUNEL assay, Western Blotting, CCK-8 assay, etc. to evaluate cell proliferation and apoptosis in testicular tissues and GC-2 cells.

RESULTS

Our findings indicated that Rab25 was expressed in germ cells and Leydig cells in the testes. Although the weight of Rab25-/- mice testes exhibited no significant changes, fertility was compromised, with a decrease in sperm quantity and reduced motility. HE staining revealed a disorganized arrangement of germ cells and vacuolization. Additionally, chromatin marginalization and nuclear pyknosis were observed in the Rab25-/- mice. In both Rab25-/- mice testes and Rab25 knockdown GC-2 cells, we found that germ cell proliferation was reduced, while apoptosis was increased.

CONCLUSIONS

In conclusion, our study proposes that Rab25 plays a vital role in spermatogenesis by regulating the proliferation and apoptosis of germ cells.

Rab25 is involved in hypospadias via the β1 integrin/EGFR pathway

BACKGROUND

Hypospadias is a common congenital abnormality of the penile. Abnormal regulation of critical genes involved in urethral development leads to hypospadias. We used the Rab25-/- mice and foreskin fibroblasts transfected with lentivirus in vitro and in vivo to investigate the role of Rab25 in hypospadias.

METHODS

The expression levels of various molecules in tissue samples and foreskin fibroblasts were confirmed using molecular biology methods (western blotting, PCR, immunohistochemistry, etc.). A scanning electron microscope (SEM) was used to visualize the external morphology of genital tubercles (GTs) of gestation day (GD) 18.5 male wild-type (WT) and Rab25-/- mice.

RESULTS

An expanded distal cleft and V-shaped urethral opening were observed in GD 18.5 Rab25-/- mice. We demonstrated that Rab25 mediated hypospadias through the β1 integrin/EGFR pathway. In addition, silencing Rab25 inhibited cell proliferation and migration and promoted apoptosis in the foreskin fibroblasts; Ki-67- and TUNEL-positive cells were mainly concentrated near the urethral seam.

CONCLUSION

These findings suggest that Rab25 plays an essential role in hypospadias by activation of β1 integrin/EGFR pathway, and Rab25 is a critical mediator of urethral seam formation in GD18.5 male fetal mice.