Dysregulated expression of androgen metabolism genes and genetic analysis in hypospadias

The association and underlying mechanism of the digit ratio (2D:4D) in hypospadias

The second-to-fourth digit (2D:4D) ratio is thought to be associated with prenatal androgen exposure. However, the relationship between the 2D:4D ratio and hypospadias is poorly understood, and its molecular mechanism is not clear. In this study, by analyzing the hand digit length of 142 boys with hypospadias (23 distal, 68 middle, and 51 proximal) and 196 controls enrolled in Shanghai Children's Hospital (Shanghai, China) from December 2020 to December 2021, we found that the 2D:4D ratio was significantly increased in boys with hypospadias ( P < 0.001) and it was positively correlated with the severity of the hypospadias. This was further verified by the comparison of control mice and prenatal low testosterone mice model obtained by knocking out the risk gene (dynein axonemal heavy chain 8 [ DNAH8 ]) associated with hypospadias. Furthermore, the discrepancy was mainly caused by a shift in 4D. Proteomic characterization of a mouse model validated that low testosterone levels during pregnancy can impair the growth and development of 4D. Comprehensive mechanistic explorations revealed that during the androgen-sensitive window, the downregulation of the androgen receptor (AR) caused by low testosterone levels, as well as the suppressed expression of chondrocyte proliferation-related genes such as Wnt family member 5a ( Wnt5a ), Wnt5b , Smad family member 2 ( Smad2 ), and Smad3 ; mitochondrial function-related genes in cartilage such as AMP-activated protein kinase ( AMPK ) and nuclear respiratory factor 1 ( Nrf-1 ); and vascular development-related genes such as myosin light chain ( MLC ), notch receptor 3 ( Notch3 ), and sphingosine kinase 1 ( Sphk1 ), are responsible for the limitation of 4D growth, which results in a higher 2D:4D ratio in boys with hypospadias via decreased endochondral ossification. This study indicates that the ratio of 2D:4D is a risk marker of hypospadias and provides a potential molecular mechanism.

Retrospective studies and quantitative proteomics reveal that abnormal expression of blood pressure, blood lipids, and coagulation related proteins is associated with hypospadias

Hypospadias refers to the abnormal position of the male urethral orifice, which not only leads to urination disorder but also causes sexual dysfunction in adulthood. However, the complex and diverse pathogenic factors of hypospadias are still unclear. To study the pathogenesis and prognosis of hypospadias, we counted the serological indexes of children with hypospadias, and found that sSBP, TC and LDL increased in children with mild, moderate and severe hypospadias. Subsequently, we used quantitative proteomics to find differential proteins in mild, moderate and severe hypospadias. After bioinformatics analysis and biochemical experiments on the screened DEPs, we found that the expression of proteins related to immune inflammation, coagulation, blood pressure and inflammation, and blood lipid were differential expressed in the prepuce tissue of children with hypospadias. We further confirmed that the proteins FGB, FGG, SERPINA1, and AGT involved in the angiotensin system, cholesterol metabolism, and coagulation were significantly up-regulated by biochemical experiments. In particular, the AGT protein of the angiotensin system involved in blood pressure regulation, we have shown that it increases with the severity of hypospadias. This study suggests that children with hypospadias are more likely to suffer from hyperlipidemia and cardiovascular disease (CVD). Our findings provide a theoretical basis for early monitoring of blood lipids and blood pressure to prevent CVD in children with hypospadias.

hsa_circ_0000417 downregulation suppresses androgen receptor expression and apoptotic signals in human foreskin fibroblasts via sponging miR-6756-5p

BACKGROUND

Dysregulated apoptosis of penile mesenchymal cells during male urethragenesis has been previously demonstrated to underly hypospadiac urethral closure failure, and androgen receptor (AR) has been shown to play a central role in regulating penile mesenchyme cell proliferation and survival. However, the regulatory mechanisms upstream and downstream of AR remain poorly understood. Our clinical data and bioinformatics analysis previously indicated that hsa_circ_0000417, a circRNA significantly downregulated in hypospadias preputial specimens, may act as a ceRNA for AR via sequestering hsa_miR-6756-5p, and that the biological functions of hsa_circ_0000417 may significantly involve the PI3K/AKT pathway. In this study, we employed human foreskin fibroblasts (HFF-1) to experimentally validate this putative hsa_circ_0000417/miR-6756-5p/AR axis and its impact on penile mesenchymal cell proliferation and apoptosis.

METHOD AND RESULTS

We showed that hsa_circ_0000417 knockdown significantly promoted proliferation and suppressed apoptosis of HFF-1 cells. Mechanistically, hsa_circ_0000417 functioned as a molecular sponge for miR-6756-5p in HFF-1 cells and relieved the latter's translational repression on AR mRNA, leading to decreased AKT activation and increased expression of pro-apoptotic proteins BAX and cleaved-caspase 9. Conversely, elevated levels of miR-6756-5p resulted in diminished AR expression concomitant with enhanced AKT activation and HFF-1 cell proliferation.

CONCLUSIONS

Collectively, our data describe for the first time a circRNA-mediated post-transcriptional regulatory mechanism of AR and its functional consequences in penile mesenchymal cells in the context of hypospadias. These findings may contribute to advancing our current understanding of the roles of AR and mesenchymal cell fate decisions during penile morphogenesis.

Whole-exome sequencing study of hypospadias

Hypospadias results from the impaired urethral development, which is influenced by androgens, but its genetic etiology is still unknown. Through whole exome sequencing analysis, we identified NR5A1, SRD5A2, and AR as mutational hotspots in the etiology of severe hypospadias, as these genes are related to androgen signaling. Additionally, rare damaging variants in cilia-related outer dynein arm heavy chain (ODNAH) genes (DNAH5, DNAH8, DNAH9, DNAH11, and DNAH17) (p = 8.5 × 10-47) were significantly enriched in hypospadias cases. The Dnah8 KO mice exhibited significantly decreased testosterone levels, which had an impact on urethral development and disrupted steroid biosynthesis. Combined with trios data, transcriptomic, and phenotypical and proteomic characterization of a mouse model, our work links ciliary genes with hypospadias. Overall, a panel of ODNAH genes with rare damaging variants was identified in 24% of hypospadias patients, providing significant insights into the underlying pathogenesis of hypospadias as well as genetic counseling.

Molecular genetics and general management of androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS) is a rare genetic disorder that affects the development of the male reproductive system in individuals with a 46,XY karyotype. In addition to physical impacts, patients with AIS may face psychological distress and social challenges related to gender identity and acceptance. The major molecular etiology of AIS results from hormone resistance caused by mutations in the X-linked androgen receptor (AR) gene. Depending on the severity of androgen resistance, the wide spectrum of AIS can be divided into complete AIS (CAIS), partial AIS (PAIS), or mild AIS (MAIS). Open issues in the treatment and management of AIS include decisions about reconstructive surgery, genetic counseling, gender assignment, timing of gonadectomy, fertility and physiological outcomes. Although new genomic approaches have improved understanding of the molecular causes of AIS, identification of individuals with AIS can be challenging, and molecular genetic diagnosis is often not achievable. The relationship between AIS genotype and phenotype is not well established. Therefore, the optimal management remains uncertain. The objective of this review is to outline the recent progress and promote understanding of AIS related to the clinical manifestation, molecular genetics and expert multidisciplinary approach, with an emphasis on genetic etiology.

Dysregulated expression of androgen metabolism genes and genetic analysis in hypospadias

Background

The aberrant expression of genes involved in androgen metabolism and genetic contribution are unclear in hypospadias.

Methods

We compared gene expression profiles by RNA sequencing from five non‐hypospadiac foreskins, five mild hypospadiac foreskins, and five severe hypospadiac foreskins. In addition, to identify rare coding variants with large effects on hypospadias risk, we carried out whole exome sequencing in three patients in a hypospadias family.

Results

The average expression of androgen receptor (AR) and CYP19A1 were significantly decreased in severe hypospadias (p < .01) and mild hypospadias (p < .05), whereas expression of several other androgen metabolism enzymes, including CYP3A4, HSD17B14, HSD3B7, HSD17B7, CYP11A1 were exclusively significantly expressed in severe hypospadias (p < .05). Compound rare damaging mutants of AR gene with HSD3B1 and SLC25A5 genes were identified in the different severe hypospadias.

Conclusions

In conclusion, our findings demonstrated that dysregulation of AR and CYP19A1 could play a crucial role in the development of hypospadias. Inconsistent AR expression may be caused by the feedback loop of ESR1 signaling or combined genetic effects with other risk genes. This findings complement the possible role of AR triggered mechanism in the development of hypospadias.