LncRNAs activate longevity regulation pathway due to aging of Leydig cells caused by DEHP exposure: A transcriptome-based study

Use of in vitro methodology to investigate phthalate effects on the differentiation of seminiferous tubule-associated stem cells to form Leydig cells and on the Leydig cells derived from the stem cells

Introduction: Leydig cells isolated from the testis are able to sustain high levels of testosterone production in vitro, but only for up to 3 days. Such cells are valuable for addressing the acute effects of chemicals on steroidogenic function, but not for repeated or chronic effects. Methodology is now available by which adult Leydig cells can be derived in vitro from seminiferous tubule-associated stem cells. In contrast to isolated Leydig cells, the Leydig cells derived in this way can synthesize and secrete high levels of testosterone for months. Herein, we asked whether this system might be used to address the effect of mono-(2-ethylhexyl) phthalate (MEHP) exposure on the formation of Leydig cells from tubule-associated stem cells, and on the Leydig cells after their formation. Methods: Adult Brown Norway rats received an intraperitoneal injection of ethane dimethanesulfonate (EDS) to eliminate the existing Leydig cells. Seminiferous tubules then were isolated and cultured in medium containing Insulin-Transferrin- Selenium (ITS), Smoothened Agonist (SAG), and luteinizing hormone (LH). Results: Culture of the tubules for 8 weeks resulted in the formation of cells on the surfaces of the tubules that stained for CYP11A1 and STAR and produced high levels of testosterone. When the tubules were cultured in medium containing increasing concentrations of MEHP, concentration-dependent effects on Leydig cell formation occurred. To determine the effect of MEHP on newly produced Leydig cells, tubules were cultured for 8 weeks in the absence of MEHP, resulting in the formation of adult Leydig cells, and then in medium containing increasing concentrations of MEHP. Concentration-dependent decreases in testosterone production by the adult Leydig cells were seen, and these decreases proved to be reversible. Discussion: The use of this new system should make it possible to determine the mechanisms by which acute, repeated, or chronic exposures to increasing concentrations of MEHP and/or exposure to other chemicals affect the formation of Leydig cells from stem cells, as well as the steroidogenic function of adult Leydig cells.

Integrated transcriptomic and biochemical characterization of the mechanisms governing stress responses in soil-dwelling invertebrate (Folsomia candida) upon exposure to dibutyl phthalate

Dibutyl phthalate (DBP) is one of the most commonly utilized plasticizers and a frequently detected phthalic acid ester (PAE) compound in soil samples. However, the toxicological effects of DBP on soil-dwelling organisms remain poorly understood. This study employed a multi-biomarker approach to investigate the impact of DBP exposure on Folsomia candida's survival, reproduction, enzyme activity levels, and transcriptional profiles. Analyses of antioxidant biomarkers, including catalase (CAT) and glutathione S-transferase (GST), as well as detoxifying enzymes such as acetylcholinesterase (AChE), Cytochrome P450 (CYP450), and lipid peroxidation (LPO), revealed significant increases in CAT activity, GST levels, and CYP450 expression following treatment with various doses of DBP for 2, 4, 7, or 14 days. Additionally, LPO induction was observed along with significant AChE inhibition. In total, 3175 differentially expressed genes (DEGs) were identified following DBP treatment that were enriched in six Gene Ontology (GO) terms and 144 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including 85 upregulated and 59 downregulated primarily associated with lipid metabolism, signal transduction, DNA repair, and cell growth and death. Overall these results provide foundational insights for further research into the molecular mechanisms underlying responses of soil invertebrates to DBP exposure.

Prenatal DEHP Exposure Induces Premature Testicular Aging by Promoting Leydig Cell Senescence through the MAPK Signaling Pathways

Previous studies show that prenatal di-(2-ethylhexyl) phthalate (DEHP) exposure induces premature testicular aging. However, the evidence is weak, and the underlying mechanisms remain unclear. p38/extracellular signal-regulated kinase (ERK)/c-Jun NH(2)-terminal kinase (JNK) MAPK pathways participate in aging. Leydig cell (LC) senescence results in testicular aging. Whether prenatal DEHP exposure induces premature testicular aging by promoting LC senescence warrants further study. Here, male mice undergo prenatal exposure to 500 mg per kg per day DEHP, and TM3 LCs are treated with 200 µm mono (2-ethylhexyl) phthalate (MEHP). MAPK pathways, testicular toxicity, and senescent phenotypes (β-gal activity, p21, p16, and cell cycle) of male mice and LCs are explored. Prenatal DEHP exposure induces premature testicular aging in middle-aged mice (poor genital development, reduced testosterone synthesis, poor semen quality, increased β-gal activity, and upregulated expression of p21 and p16). MEHP induces LCs senescence (cell cycle arrest, increased β-gal activity, and upregulated expression of p21). p38 and JNK pathways are activated, and the ERK pathway is inactivated. In conclusion, prenatal DEHP exposure induces premature testicular aging by promoting LC senescence through MAPK signaling pathways.

Protective role of autophagy in triptolide-induced apoptosis of TM3 Leydig cells

Background and Objectives

Triptolide (TP) is known to impair testicular development and spermatogenesis in mammals, but the mechanism of the side effects still needs to be investigated. The aim of the research is to confirm whether TP can cause autophagy in TM3 Leydig cells and the potential molecular pathway in vitro.

Methods

TM3 Leydig cells are used to investigate the molecular pathway through Western blot, detection of apoptosis, transmission electron microscopy for autophagosomes and so on.

Results

The data show that TP treatment resulted in the decreasing of the viability of TM3 cells due to the increased apoptosis. Treated with TP, the formation of autophagosomes, the decrease in P62, and the increase in the conversion of LC3-I to LC3-II suggested the induction of autophagy. The induction of autophagy has accompanied the activation of the mTOR/P70S6K signal pathway. The viability of the TM3 cells was further inhibited when they were co-treated with autophagy inhibitor, chloroquine (CQ).

Conclusion

All these data suggest that autophagy plays a very important role in antagonizing TM3 cell apoptosis during the TP exposure.

Plasticizer DEHP exposure in early pregnancy affects the endometrial decidualization in mice through reducing lncRNA RP24-315D19.10 expression

OBJECTIVES

To explore the effect of exposure to di (2-ethyl) hexyl phthalate (DEHP) in early pregnancy on endometrial decidualization in mice and its relation with lncRNA RP24-315D19.10.

METHODS

Early pregnancy mice were exposed to DEHP (1000 mg·kg－1·d－1) to construct the model. The uterus was collected on day 6 of pregnancy to detect its effect on decidualization by HE staining and immunofluorescence. A decidualization induction model of mouse endometrial stromal cells exposed to DEHP (0.1, 0.5, 2.5, 12.5, 62.5 μmol/L) was constructed. The changes of cell morphology were observed by light microscopy and phalloidin staining, and the expression of decidual reaction related molecular markers were detected by immunofluorescence, realtime RT-PCR and Western blotting. The expression of RP24-315D19.10 in decidua tissue and cells was detected by realtime RT-PCR. Cellular localization of RP24-315D19.10 was determined by lncLocator database and RNA FISH. AnnoLnc2 database was used to predict miRNAs bound to RP24-315D19.10.

RESULTS

The number of embryo implantation sites, uterine weight and uterine area were significantly lower in the DEHP exposed group than those in the control group, and the expression of the decidual reaction related molecular markers matrix metalloprotein 9 and homeobox A10 in the DEHP exposure group were also significantly lower than those in the control group (all P<0.05). With the increase of DEHP concentration, the expression of dtprp in decidua cells was gradually decreased. 2.5 μmol/L DEHP exposed stromal cells failed to be fully decidualized in vitro, andphalloidin staining showed abnormal cytoskeleton morphology. The expression levels of homeobox A10, bone morphogenetic protein 2 and proliferating cell nuclear antigen in the DEHP exposure group were significantly lower than those in the control group (all P<0.05). The expression of RP24-315D19.10 in DEHP exposed decidua tissue and cells was significantly reduced (both P<0.05). RP24-315D19.10 is mainly localized in the cytoplasm and RP24-315D19.10 might bind to 45 miRNAs, among them, miR-138-5p, miR-155-5p, miR-183-5p and miR-223-3p were associated with endometrial decidualization.

CONCLUSIONS

DEHP exposure in early pregnancy may impair endometrial decidualization, and the damage may be associated with the down-regulation of RP24-315D19.10.

N6-methyladenosine modification on Hmbox1 is related to telomere dysfunction in DEHP-induced male reproductive injury

AIMS

Di (2-ethylhexyl) phthalate (DEHP), as an environmental endocrine-disrupting chemical (EDC), can induce male reproductive injury. N6-methyladenosine (m6A) plays a vital role in environmental exposure-induced diseases by regulating gene expression. Therefore, we aim to investigate the role of m6A in DEHP-induced reproductive injury.

MAIN METHODS

We established an in vivo model of mice exposed to DEHP to explore the effect of DEHP on reproductive injury and m6A. To further explore the molecular mechanism of DEHP toxicity, we built a model of GC-2 cells exposed to mono-(2-ethylhexyl) phthalate (MEHP) in vitro and further silenced Mettl3 in GC-2cells. Besides, we also conducted MeRIP-qPCR and RIP assays to identify the target genes for m6A modification.

KEY FINDINGS

DEHP induced testicular injury and senescence. And telomeres shortening, reduced levels of telomere repeat-binding factor 1 (TRF1), TRF2, protection of telomeres 1 (POT1), and telomerase reverse transcriptase (TERT) can be observed in DEHP-treated testes. MEHP also induced GC-2 cellular senescence and telomere dysfunction. Besides, increased m6A mediated by METTL3 stabilized homeobox containing 1 (Hmbox1) in an m6A-dependent manner in MEHP-exposed GC-2 cells. Mettl3 knockdown led to lower m6A modification and reduced Hmbox1 stability, resulting in further shortening of telomere length.

SIGNIFICANCE

our work uncovered that DEHP led to male reproductive injury by telomere dysfunction and m6A modified Hmbox1 contributed to maintaining telomere homeostasis in this process, suggesting that accurate regulation of m6A modification level by drugs has potential value in the treatment of DEHP-induced male reproductive injury.

Di-(2-ethylhexyl) phthalate exposure leads to ferroptosis via the HIF-1α/HO-1 signaling pathway in mouse testes

Di-(2-ethylhexyl) phthalate (DEHP) is an extensively used plasticizer and has been shown to cause reproductive dysfunction in humans and model animals. However, the exact mechanisms of testicular injury induced by DEHP exposure have not been fully clarified. Using gas chromatography-mass spectrometry, we found that mono-2-ethylhexyl ester (MEHP, a major biometabolite of DEHP) and DEHP concentrations were elevated in mouse serum after DEHP exposure. Using RNA-seq, we found that ferroptosis and HIF-1 signaling pathways might be involved in testicular injury due to prepubertal DEHP exposure. Subsequent Western blotting, ferrous iron and MDA measurements, and immunofluorescence of testicular sections verified the RNA-seq findings. Consistently, based on the RNA-seq findings, we found that ferroptosis and HIF-1 signaling pathways might play crucial roles in Leydig and Sertoli cell injury due to MEHP exposure in vitro. Further experiments also confirmed ferroptosis in Leydig and Sertoli cells. Using Western blotting, cellular immunofluorescence and ChIP-qPCR, we found that MEHP exposure caused HIF-1α accumulation and stabilization, resulted in HIF-1α translocation into the nucleus, and induced HIF-1α/Hmox1 binding in Leydig and Sertoli cells. To clarify whether HIF-1α plays a pivotal role in MEHP-induced ferroptosis, we knocked out Hif-1α using the CRISPR/Cas9 technique. We found that Hif-1α knockout rescued MEHP-induced ferroptosis. In summary, our findings certified that prepubertal DEHP exposure led to ferroptosis in mouse testes via the HIF-1α/HO-1 signaling pathway.