Di-n-butyl phthalate (DBP) reduces epithelial-mesenchymal transition via IP3R in hypospadias during maternal exposure

Identification and analysis of epithelial-mesenchymal transition-related key long non-coding RNAs in hypospadias

EMT dysfunction is a dominant mechanisms of hypospadias. Thus, identification of EMT-related lncRNAs based on transcriptome sequencing data of hypospadias might provide novel molecular markers and therapeutic targets for hypospadias. First, the microarray data related to hypospadias were downloaded from Gene Expression Omnibus (GEO). Besides, the differentially expressed lncRNAs and messenger RNAs (mRNAs) related to EMT were screened to construct lncRNA-mRNA co-expression interaction pairs. In addition, the microRNA (miRNA) prediction analysis was performed through bioinformatics methods to construct a ceRNA network. Moreover, function prediction and function enrichment and pathway analyses were also performed. Finally, the core EMT-related lncRNAs were verified based on mRNA expression changes and cell functions. A total of 6 EMT-related lncRNAs were identified and 123 mRNA-lncRNA co-expression interaction pairs were screened in this study. Additionally, a ceRNA regulatory network comprising 17 mRNAs, 4 lncRNAs, and 28 miRNAs was constructed based on the prediction of hypospadias-related miRNAs. The validation results of the dataset GSE121712 revealed that only BEX1 was positively correlated with the expression of the lncRNA GNAS-AS1 (r = 0.874, P < 0.01), both of which had high expression. The cell experiment results demonstrated that interfering with the expression of GNAS-AS1 significantly promoted the proliferation, migration, and EMT of cells. Importantly, it was confirmed that GNAS-AS1 can serve as a ceRNA and play an important role in the EMT of hypospadias. Hence, it may be considered as a potential target in the treatment of this disease.

Identification and analysis of MSC-Exo-derived LncRNAs related to the regulation of EMT in hypospadias

OBJECTIVE

This study aims to screen the differentially expressed long non-coding RNAs (DELncRNAs) related to the regulation of epithelial-mesenchymal transition (EMT) in hypospadias in mesenchymal stem cell-derived exosomes (MSC-Exons) and explore the potential mechanism of these lncRNAs for the EMT in hypospadias.

METHODS

In this study, the microarray data related to MSC-Exos and hypospadias were downloaded from Gene Expression Omnibus (GEO). Besides, the lncRNAs highly expressed in MSC-Exos and the differentially expressed mRNAs and lncRNAs in children with hypospadias were screened, respectively. In addition, the lncRNAs enriched in MSC-Exos and differentially expressed lncRNAs in hypospadias were intersected to obtain the final DElncRNAs. Moreover, the co-expression interaction pairs of differentially expressed lncRNAs and mRNAs were analyzed to construct a Competing Endogenous RNA (ceRNA) network. Finally, the candidate lncRNAs in exosomes were subjected to in vitro cell function verification.

RESULTS

In this study, a total of 4 lncRNAs were obtained from the microarray data analysis. Further, a ceRNA regulatory network of MSC-Exo-derived lncRNAs related to the regulation of EMT in hypospadias was constructed, including 4 lncRNAs, 2 mRNAs, and 6 miRNAs. The cell function verification results indicated that the exosomes secreted by MSCs may transport HLA complex group 18 (HCG18) into target cells, which promoted the proliferation, migration, and EMT of these cells.

CONCLUSION

MSC-Exo-derived lncRNA HCG18 can enter target cells, and it may be involved in the regulation of EMT in hypospadias through the ceRNA network.

Dibutyl phthalate (DBP) promotes Epithelial-Mesenchymal Transition (EMT) to aggravate liver fibrosis into cirrhosis and portal hypertension (PHT) via ROS/TGF-β1/Snail-1 signalling pathway in adult rats

OBJECTIVE

The primary objective of this study was to investigate the toxicological impact of Dibutyl phthalate (DBP) on the process of liver fibrosis transitioning into cirrhosis and the subsequent development of portal hypertension (PHT) through the mechanism of epithelial-mesenchymal transition (EMT) mediated by the ROS/TGF-β/Snail-1 signaling pathway.

METHOD

Carbon tetrachloride (CCl4) (1 mg/kg) was introduced in adult rats by oral feeding in CCl4 and CCl4+DBP groups twice a week for 8 weeks, and twice for another 8 week in CCl4 group. DBP was introduced by oral feeding in the CCl4+DBP group twice over the following 8 weeks. We subsequently analyzed hemodynamics measurements and liver cirrhosis degree, hepatic inflammation and liver function in the different groups. EMT related genes expression in rats in the groups of Control, DBP, CCl4 and CCl4+DBP were measured by immunohistochemistry (IHC). Enzyme-linked immunosorbent Assay (ELISA), qRT-PCR, western blot were used to detect the EMT related proteins and mRNA gene expression levels in rats and primary hepatocytes (PHCs). Reactive oxygen species (ROS) were examined with a ROS detection kit.

RESULTS

The results showed that the CCl4+DBP group had higher portal pressure (PP) and lower mean arterial pressure (MAP) than the other groups. Elevated collagen deposition, profibrotic factor, inflammation, EMT levels were detected in DBP and CCl4+DBP groups. ROS, TGF-β1 and Snail-1 were highly expressed after DBP exposure in vitro. TGF-β1 had the potential to regulate Snail-1, and both of them were subject to regulation by ROS.

CONCLUSION

DBP could influence the progression of EMT through its toxicological effect by ROS/TGF-β1/Snail-1 signalling pathway, causing cirrhosis and PHT in final. The findings of this research might contribute to a novel comprehension of the underlying toxicological mechanisms and animal model involved in the progression of cirrhosis and PHT, and potentially offered a promising therapeutic target for the treatment of the disease.

Maternal exposure to dibutyl phthalate (DBP) impairs angiogenesis and AR signalling pathway through suppression of TGFB1I1 in hypospadias offspring

Early exposure to dibutyl phthalate (DBP) can cause hypospadias in newborn foetuses. However, the underlying molecular mechanism is not well defined. Aberrant angiogenesis is associated with various dysplasias including urogenital deficits. In vivo and in vitro angiogenesis assays showed reduced angiogenesis in the hypospadias group and DBP exposed group. RNA-sequencing analysis of DBP-treated HUVECs revealed decreased expression of transforming growth factor beta 1-induced transcript 1 (TGFB1I1) and a significantly enriched angiogenesis-associated pathway. Further experiments revealed that decreased TGFB1I1 expression was associated with disrupted tube formation and migration, which resulted in decreased angiogenesis. Functional assays revealed that the overexpression of TGFB1I1 promoted tube formation and migration of HUVECs in the DBP-treated group. Moreover, we showed that the transcription factor AR was regulated by TGFB1I1 through inhibiting its translocation from the cytoplasm to the nucleus. Together, our results identified TGFB1I1 as a component of aberrant angiogenesis in hypospadias rats and its interaction with AR might be a potential target for hypospadias development.

Urinary extracellular vesicles prevent di-(2-ethylhexyl) phthalate-induced hypospadias by facilitating epithelial-mesenchymal transition via PFN2 delivery

BACKGROUND

Urinary extracellular vesicles (EVs) have gained increasing interest in recent years as a potential source of noninvasive biomarkers of diseases related to urinary organs, but knowledge of the mechanism is still limited. The current study sought to clarify the mechanism of urinary EVs behind di-(2-ethylhexyl) phthalate (DEHP)-induced hypospadias via PFN2 delivery.

METHOD

PFN2 expression in hypospadias was predicted by bioinformatics analysis. Following the induction of a hypospadias rat model using DEHP, rats were injected with EVs and/or underwent alteration of PFN2 and TGF-β1 to assess their effects in vivo. The extracted rat urothelial cells (UECs) were co-cultured with EVs extracted from urine for in vitro experiments.

RESULT

Microarray analysis predicted poor PFN2 expression in hypospadias. Upregulated PFN2 was found in urinary EVs, and restrained epithelial-mesenchymal transition (EMT) was observed in DEHP-exposed rats. Urinary EVs or PFN2 overexpression increased SMAD2, SMAD3, and TGF-β1 protein expression and SMAD2 and SMAD3 phosphorylation in UECs and DEHP-exposed rats. UEC migration, invasion, and EMT were augmented by EV co-culture or upregulation of PFN2. Of note, the silencing of TGF-β1 counterweighed the effect of PFN2. Besides, EV co-culture or overexpression of PFN2 or TGF-β1 elevated the body weight, anal-genital distance (AGD), anal-genital index (AGI), and EMT of DEHP-exposed rats.

CONCLUSION

In summary, urinary EVs activated the SMAD/TGF-β1 pathway to induce EMT via PFN2 delivery, thus protecting against DEHP-induced hypospadias. (1) EMT in epithelial cells inhibits DEHP-induced hypospadias. (2) Urine-derived EVs deliver PFN2 to promote EMT in epithelial cells. (3) PFN2 can activate the SMAD/TGF-β1 signaling axis. (4) Urine-derived EVs can transmit PFN2 to activate the SMAD/TGF-β1 signaling axis, thus promoting EMT and inhibiting the occurrence of hypospadias.

Prenatal DEHP exposure predicts neurological disorders via transgenerational epigenetics

Recent experimental and observational research has suggested that childhood allergic asthma and other conditions may be the result of prenatal exposure to environmental contaminants, such as di-(2-ethylhexyl) phthalate (DEHP). In a previous epidemiological study, we found that ancestral exposure (F0 generation) to endocrine disruptors or the common plasticizer DEHP promoted allergic airway inflammation via transgenerational transmission in mice from generation F1 to F4. In the current study, we employed a MethylationEPIC Beadchip microarray to examine global DNA methylation in the human placenta as a function of maternal exposure to DEHP during pregnancy. Interestingly, global DNA hypomethylation was observed in placental DNA following exposure to DEHP at high concentrations. Bioinformatic analysis confirmed that DNA methylation affected genes related to neurological disorders, such as autism and dementia. These results suggest that maternal exposure to DEHP may predispose offspring to neurological diseases. Given the small sample size in this study, the potential role of DNA methylation as a biomarker to assess the risk of these diseases deserves further investigation.

USP15 participates in DBP-induced testicular oxidative stress injury through regulating the Keap1/Nrf2 signaling pathway

Di-n-butylphthalate (DBP) has been listed as an environmental priority pollutant in China due to its distinct biotoxicity. Epidemiological studies have shown that exposure to DBP is closely related to a series of congenital and acquired defects in the male reproductive system. The oxidative stress injury caused by DBP plays an important role in these defects. Previous studies have demonstrated that the Keap1/Nrf2 antioxidative pathway plays a protective role in DBP-induced oxidative stress injury. However, the further molecular regulation mechanism of the activation of Nrf2 pathway remains unclear. Here, we demonstrate that DBP caused testicular oxidative stress injury and Nrf2 pathway was activated in response to the injury in vivo and in vitro. Moreover, we validated that reduced level of USP15 attenuates DBP-induced oxidative stress injury through restraining the ubiquitylation and degradation of Nrf2. Notably, USP15 is confirmed as a target of miR-135b-5p and miR-135b-5p mediated inhibition of USP15 is involved in the DBP-induced oxidative stress injury. Collectively, these findings indicated that decreased level of USP15 functions a significant protective effect on the oxidative stress injury of testis caused by DBP via regulating the Keap1/Nrf2 signaling pathway.

Increased hypospadias risk by GREM1 rs3743104[G] in the southern Han Chinese population

Hypospadias is a common congenital genitourinary malformation characterized by ventral opening of the urethral meatus. As a member of the bone morphogenic protein antagonist family, GREM1 has been identified as associated with susceptibility to hypospadias in the European population. The present study was designed to elaborate on the mutual relationship between replicated single-nucleotide polymorphisms (SNPs) and hypospadias in Asia's largest case-control study in the Southern Han Chinese population involving 577 patients and 654 controls. Our results demonstrate that the GREM1 risk allele rs3743104[G] markedly increases the risk of mild/moderate and severe hypospadias (P<0.01, 0.28≤OR≤0.66). GTEx expression quantitative trait locus data revealed that the eQTL SNP rs3743104 has more associations of eQTL SNP rs3743104 and GREM1 targets in pituitary tissues. Additionally, Bioinformatics and Luciferase Assays show that miR-182 is identified as a suppressor for GREM1 expression, likely through regulation of its binding affinity to rs3743104 locus. In conclusion, the GREM1 risk allele rs3743104[G] increases hypospadias susceptibility in mild/moderate and severe cases among the southern Han population. rs3743104 regulates GREM1 expression by altering the binding affinity of miR-182 to their locus. Collectively, this study provides new evidence that GREM1 rs3743104 is associated with an increased risk of hypospadias. These findings provide a promising biomarker and merit further exploration.

Dibutyl phthalate-induced oxidative stress, inflammation and apoptosis in grass carp hepatocytes and the therapeutic use of taxifolin

The widespread use of plastic products has led to the widespread presence of plasticizers in the environment. As a common environmental pollutant, research on plasticizer toxicity is insufficient in fish cells. In particular, research on the toxicity of dibutyl phthalate (DBP) in grass carp hepatocyte lines is insufficient. To further explore these mechanisms, we treated grass carp hepatocytes with 300 μM DBP, a common plasticizer, for 24 h, and hepatocytes were also treated with 1 μM taxifolin (TAX), an antioxidant, for 24 h to study its antagonistic effect on DBP. After DBP exposure, oxidative stress levels and inflammation in hepatocytes increased, and the mRNA and protein expression of apoptosis-related markers increased significantly, leading to hepatocyte apoptosis. Moreover, AO/EB staining, Hoechst staining and flow cytometry also showed that the level of apoptotic cells increased after DBP exposure. Notably, both TAX pretreatment and TAX simultaneous treatment alleviated oxidative stress, increased inflammatory factor levels and apoptosis induced by DBP. In comparison, the effect of simultaneous TAX treatment was better than that of TAX pretreatment. Our results showed that TAX alleviates DBP-induced apoptosis in grass carp hepatocytes through oxidative stress and inflammation, and TAX pretreatment and simultaneous treatment exhibited specific effects. Specifically, simultaneous treatment had a better effect. Our study assessed the toxicity of DBP in grass carp hepatocytes and provided a theoretical and research basis for the in vivo study of animal models in the future. The innovation of this study involves the exploration of the interaction between DBP and TAX for the first time. This study may enrich knowledge regarding the theoretical mechanism of DBP toxicity in fish hepatocytes and propose methods address DBP toxicity.

Endocrine disrupting chemicals in the pathogenesis of hypospadias; developmental and toxicological perspectives

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Penis development is regulated by a tight balance of androgens and estrogens.

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EDCs that impact androgen/estrogen balance during development cause hypospadias.

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Cross-disciplinary collaborations are needed to define a mechanistic link.

Hypospadias is a defect in penile urethral closure that occurs in approximately 1/150 live male births in developed nations, making it one of the most common congenital abnormalities worldwide. Alarmingly, the frequency of hypospadias has increased rapidly over recent decades and is continuing to rise. Recent research reviewed herein suggests that the rise in hypospadias rates can be directly linked to our increasing exposure to endocrine disrupting chemicals (EDCs), especially those that affect estrogen and androgen signalling. Understanding the mechanistic links between endocrine disruptors and hypospadias requires toxicologists and developmental biologists to define exposures and biological impacts on penis development. In this review we examine recent insights from toxicological, developmental and epidemiological studies on the hormonal control of normal penis development and describe the rationale and evidence for EDC exposures that impact these pathways to cause hypospadias. Continued collaboration across these fields is imperative to understand the full impact of endocrine disrupting chemicals on the increasing rates of hypospadias.