BRD7 facilitates ferroptosis via modulating clusterin promoter hypermethylation and suppressing AMPK signaling in diabetes-induced testicular damage.

BACKGROUND: Diabetes mellitus (DM)-induced testicular damage is associated with sexual dysfunction and male infertility in DM patients. However, the pathogenesis of DM-induced testicular damage remains largely undefined. METHODS: A streptozotocin (STZ)-induced diabetic model and high glucose (HG)-treated in vitro diabetic model were established. The histological changes of testes were assessed by H&E staining. Serum testosterone, iron, MDA and GSH levels were detected using commercial kits. Cell viability and lipid peroxidation was monitored by MTT assay and BODIPY 581/591 C11 staining, respectively. qRT-PCR, immunohistochemistry (IHC) or Western blotting were employed to detect the levels of BRD7, Clusterin, EZH2 and AMPK signaling molecules. The associations among BRD7, EZH2 and DNMT3a were detected by co-IP, and the transcriptional regulation of Clusterin was monitored by methylation-specific PCR (MSP) and ChIP assay. RESULTS: Ferroptosis was associated with DM-induced testicular damage in STZ mice and HG-treated GC-1spg cells, and this was accompanied with the upregulation of BRD7. Knockdown of BRD7 suppressed HG-induced ferroptosis, as well as HG-induced Clusterin promoter methylation and HG-inactivated AMPK signaling in GC-1spg cells. Mechanistical studies revealed that BRD7 directly bound to EZH2 and regulated Clusterin promoter methylation via recruiting DNMT3a. Knockdown of Clusterin or inactivation of AMPK signaling reverses BRD7 silencing-suppressed ferroptosis in GC-1spg cells. In vivo findings showed that lack of BRD7 protected against diabetes-induced testicular damage and ferroptosis via increasing Clusterin expression and activating AMPK signaling. CONCLUSION: BRD7 suppressed Clusterin expression via modulating Clusterin promoter hypermethylation in an EZH2 dependent manner, thereby suppressing AMPK signaling to facilitate ferroptosis and induce diabetes-associated testicular damage.

N6-Methyladenosine Methyltransferase METTL3 Alleviates Diabetes-Induced Testicular Damage through Modulating TUG1/Clusterin Axis.

BACKGROUND: The present study investigated the regulatory effects of N6-methyladenosine (m6A) methyltransferase like-3 (METTL3) in diabetes-induced testicular damage. METHODS: In vivo diabetic mice and high glucose (HG) treated GC-1 spg cells were established. The mRNA and protein expressions were determined by real-time quantitative polymerase chain reaction, Western blot, immunofluorescence and immunohistochemistry staining. Levels of testosterone, blood glucose, cell viability, and apoptosis were detected by enzyme-linked immunosorbent assay, MTT, and flow cytometry, respectively. Molecular interactions were verified by RNA immunoprecipitation and RNA pull-down assay. Histopathological staining was performed to evaluate testicular injury. RESULTS: METTL3 and long non-coding RNA taurine up-regulated 1 (lncRNA TUG1) were downregulated in testicular tissues of diabetic mice and HG-treated GC-1 spg cells. METTL3 overexpression could reduce the blood glucose level, oxidative stress and testicular damage but enhance testosterone secretion in diabetic mouse model and HG-stimulated GC-1 spg cells. Mechanically, METTL3-mediated m6A methylation enhanced the stability of TUG1, then stabilizing the clusterin mRNA via recruiting serine and arginine rich splicing factor 1. Moreover, inhibition of TUG1/clusterin signaling markedly reversed the protective impacts of METTL3 overexpression on HG-stimulated GC-1 spg cells. CONCLUSION: This study demonstrated that METTL3 ameliorated diabetes-induced testicular damage by upregulating the TUG1/clusterin signaling. These data further elucidate the potential regulatory mechanisms of m6A modification on diabetes-induced testicular injury.

A Study of the Relationship Between Students' Global Perspective and Willingness to Communicate in English at an English Medium Instruction University in China.

Few previous studies have investigated the relationship between global perspective (GP) and willingness to communicate (WTC) in English. Hence, more studies are needed to validate their correlation. Furthermore, hardly any pertaining studies have been conducted at English Medium Instruction (EMI) universities. As such, the current study aimed to fill these gaps in the context of an EMI university in China, by investigating whether GP correlates with second language (L2) WTC and what factors impact the two variables. Data were collected from students via an online questionnaire (n = 315) and follow-up interviews (n = 11). The questionnaire findings confirmed a moderate positive correlation between GP and L2 WTC. The interview data unraveled that several factors influenced students' L2 WTC, including needs and motivations driving L2 WTC, concerns constraining L2 WTC, and intercultural cognition facilitating L2 WTC. These findings suggest that: (A) students could be more determined to practice their English if they realize the significance of the role of English in their life; (B) teachers could foster students' WTC by creating a non-threatening English-speaking environment and encouraging students to communicate in English in and outside the classroom; and (C) teachers could educate students about GP and L2 WTC, which might help to expand students' horizon and stimulate their interests in foreign cultures and global affairs, so as to facilitate the sustainable growth of their English learning.

Clusterin suppresses spermatogenic cell apoptosis to alleviate diabetes-induced testicular damage by inhibiting autophagy via the PI3K/AKT/mTOR axis.

BACKGROUND INFORMATION: Diabetes-induced testicular dysfunction is characterised by abnormal apoptosis of spermatogenic cells, but the underlying mechanism is poorly understood. This study aimed to investigate the roles of clusterin (CLU) in testicular damage associated with diabetes pathogenesis, as well as the molecular mechanism. A rat diabetes model was established using streptozocin, and the mouse spermatogenic cell line GC-1 spg was treated with high glucose as a cellular model. CLU was overexpressed in GC-1 spg cells, followed by detection of serum testosterone, cell proliferation, cell apoptosis and autophagy. RESULTS: CLU expression was significantly reduced and LC3 expression was elevated in testis tissues in the rat diabetes model and high glucose-treated GC-1 spg cells. High glucose led to suppressed viability, enhanced apoptosis, reduced Bcl-2 expression, elevated Bax expression and cleavage of Caspase-3/-9 in GC-1 spg cells, and these effects were abrogated by CLU overexpression. Additionally, CLU overexpression repressed LC3 and Beclin-1 expression, reduced the LC3II/LC3I ratio and promoted p62 expression in GC-1 spg cells in the presence of high glucose, and these effects were all mitigated by rapamycin treatment. Inhibition of PI3K/AKT/mTOR signalling with LY294002 activated autophagy in CLU-overexpressing GC-1 spg cells under high glucose conditions. CLU overexpression repressed autophagy and alleviated testicular damage in diabetic rats, which was also abrogated by LY294002 treatment. CONCLUSIONS: CLU expression is suppressed during diabetes-induced testicular damage, whereas CLU overexpression alleviates diabetes-induced testicular damage by activating PI3K/AKT/mTOR signalling to inhibit autophagy and further repress spermatogenic cell apoptosis.

A Case Study on the Impacts of Social Contexts on a Chinese English as a Foreign Language Learner's L1 and L2 Identities Development.

Informed by the poststructuralist theory, this study investigates the case of Ming, a Chinese professor of English, about the impacts of his first language (L1) and second language (L2) learning experience, and the changes of social contexts on his L1 and L2 identities construction. It was found that being a learner of English as a Foreign Language (EFL), Ming's identities development aligned with the poststructuralist theory, in which it is considered dynamic, fluid and conflicting. Ming negotiated and renegotiated his identities in various social contexts in China and the United States and finally gained acceptance into the L2 academic community. This study not only analyzes Ming's experience with his language learning and identities, but also unravels that conflicts may be part of the process of identities construction, and encourages learners to be persistent and emotionally resilient, while using certain strategies to retain a stable L1 identity so that they can navigate through the negative encounters during the second language acquisition (SLA) process to sustain the development of their identities and L2 abilities.

[Impact of 4-bromobiphenyl ether on the expression of γH2AX in the rat testis].

Objective: To investigate the effects of monobromobiphenyl ether (4-BDE) on the expression of γH2AX in the rat testis, and the possible mechanism of 4-BDE affecting the reproductive function of the male rats. METHODS: Twenty-four SD male rats were randomly divided into 4 groups: control and low-, medium- and high-dose 4-BDE, the control rats treated intragastrically with olive oil, and the animals in the latter three groups with 4-BDE at 50, 100 and 200 mg/kg/d, respectively, all for 30 consecutive days. Then all the rats were killed and the testis tissues harvested for HE staining, examination of the apoptosis of the cells by TUNEL and determination of the expressions of H2AX mRNA and γH2AX by q-PCR and Western blot. RESULTS: HE staining manifested occasional reduction or absence of spermatogonial and Sertoli cells in the seminiferous tubules in the medium- and high-dose 4-BDE groups. Compared with the controls, the rats exposed to 4-BDE showed a significant dose-dependent increase in the apoptosis of the testis tissue (P < 0.05), even more significant in the medium- and high-dose 4-BDE groups than in the low-dose group (P < 0.05). There was a dose-effect relationship in the apoptosis index, but with no statistically significant difference between the medium- and high-dose 4-BDE groups (P > 0.05). The results of q-PCR exhibited no statistically significant difference in the expression level of H2AX mRNA either between the control and 4-BDE-exposed rats (P > 0.05) or among the three 4-BDE groups (P > 0.05). The expression of the γH2AX protein was remarkably higher in the 4-BDE groups than in the control (P < 0.05), but not significantly different among the 4-BDE groups (P > 0.05). CONCLUSIONS: Exposure to 4-BDE at 100 or 200 mg/kg/d damages the structure of seminiferous tubules, increases the apoptosis of testicular cells, significantly up-regulates the expression of the γH2AX protein, and consequently increases DNA double-strand breaks (DSB) in the rat testis. The apoptosis of testicular cells may be related to DSB./.

[Protective effect of taurine against formaldehyde-induced male reproductive toxicity in adult male rats].

OBJECTIVE: To study the effect of taurine on the reproductive toxicity damage induced by formaldehyde (FM) in adult male rats. METHODS: Forty-eight SD adult male rats were equally randomized into a normal control, an FM poisoning (FMP), a taurine intervention (TI), and an TI+FMP group. The control rats were given normal diet and gavage of saline, the rats of the FMP group treated intraperitoneally with FM at 10 mg/kg qd alt, those of the TI group intragastrically with taurine at 100 mg/kg qd, and those of the TI+FMP group with both FM and taurine at the above doses. After 30 days of treatment, the blood of the abdominal cardinal vein of the rats was extracted for measurement of the levels of serum hormones, the body weight, testis weight and testicular coefficient obtained, the testis tissue subjected to HE staining, and the expressions of Bcl-2 and Bax determined by Western blot. RESULTS: There were no statistically significant differences among the four groups of rats in the body weight, testis weight or testicular coefficient (P > 0.05). The rats in the FMP group showed obviously decreased testicular spermatogenic cells and disordered layers and loose structure of seminiferous tubules, which were basically restored to normal after taurine intervention. Compared with the normal controls, the animals of the TI group exhibited no significant abnormality, but those of the FMP group presented markedly reduced levels of serum T, LH and FSH (P < 0.05), and dramatically increased level of Gonadotropin-releasing hormone (GnRH) (P < 0.01). The levels of serum hormones were all significantly improved (P < 0.05) and that of the apoptotic protein Bax basically returned to normal (P < 0.05) after taurine intervention. CONCLUSIONS: Taurine has a certain protective effect against male reproductive toxicity caused by formaldehyde.

Vitamin E and lycopene reduce coal burning fluorosis-induced spermatogenic cell apoptosis via oxidative stress-mediated JNK and ERK signaling pathways.

Although fluoride has been widely used in toothpaste, mouthwash, and drinking water to prevent dental caries, the excessive intake of fluoride can cause fluorosis which is associated with dental, skeletal, and soft tissue fluorosis. Recent evidences have drawn the attention to its adverse effects on male reproductive system that include spermatogenesis defect, sperm count loss, and sperm maturation impairment. Fluoride induces oxidative stress through the activation of mitogen activated protein kinase (MAPK) cascade which can lead to cell apoptosis. Vitamin E (VE) and lycopene are two common antioxidants, being protective to reactive oxygen species (ROS)-induced toxic effects. However, whether and how these two antioxidants prevent fluoride-induced spermatogenic cell apoptosis are largely unknown. In the present study, a male rat model for coal burning fluorosis was established and the histological lesions and spermatogenic cell apoptosis in rat testes were observed. The decreased expression of clusterin, a heterodimeric glycoprotein reported to regulate spermatogenic cell apoptosis, was detected in fluoride-treated rat testes. Interestingly, the co-administration with VE or lycopene reduced fluorosis-mediated testicular toxicity and rescued clusterin expression. Further, fluoride caused the enhanced Jun N-terminal kinase (JNK, c-Jun) and extracellular signal-regulated protein kinase (ERK) phosphorylation, which was reduced by VE or lycopene. Thus, VE and lycopene prevent coal burning fluorosis-induced spermatogenic cell apoptosis through the suppression of oxidative stress-mediated JNK and ERK signaling pathway, which could be an alternative therapeutic strategy for the treatment of fluorosis.

Primary squamous cell carcinoma of the seminal vesicle: A case report.

Primary squamous cell carcinoma (SCC) is extremely rare in the seminal vesicle. A 26-year-old male patient presented with complaints of difficulty in urination for 10 years and gross hematuria for 7 months. Ultrasonography and computed tomography imaging demonstrated a large mixed solid/cystic mass lesions in the rectovesical pouch. The mass was completely resected with the open approach and was verified as a primary SCC of the seminal vesicle by post-surgical histopathological examination. Pelvic metastases were detected 28 months after the surgery. This is the third reported case of primary SCC of the seminal vesicle, and the first one in a young patient. Early diagnosis and treatment are crucial for primary SCC of the seminal vesicle.

A metanephric adenoma of the kidney associated with polycythemia: A case report.

Metanephric adenoma (MA) of the kidney is a rare and frequently benign tumor with a favorable prognosis that is often diagnosed following surgical treatment. In the present study, a 54-year-old female patient presented with complaints of intermittent right-flank pain and anterior abdominal pain occurring over 2 years and sporadic gross hematuria occurring over 3 months. Ultrasonography and computerized tomography imaging revealed a neoplasm lesion localized in the right kidney. Successful open approach radical nephrectomy was performed and post-surgical histopathological examination verified the lesion as a MA of the kidney. Radical nephrectomy, cryoablation or radiofrequency may used to treat MA and a selective panel of immunostains, including WT1, EMA and AMACR, may be useful for diagnosis.

[Fluorosis of coal burning affects the male reproductive system].

Fluorosis of coal burning is a new type of endemic fluorosis in China, which affects the male reproductive system. Furthermore, the content of fluoride in the semen, sperm mortality, sperm concentration and the incidence of infertility are higher in severe fluorosis areas than in mild- and non-fluorosis areas, so are the levels of serum follicle-stimulating hormone and luteinizing hormone. However, the levels of inhibin B, serum testosterone and estradiol show different degrees of reduction in severe fluorosis areas. Accordingly, fluorosis of coal burning, just like other endemic fluorosis, may affect the structure of male reproductive organs, the generation of sperm and reproductive endocrinology, resulting in the decline of men's reproductive ability.

[Effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis].

OBJECTIVE: To explore the effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis. METHODS: Totally 40 male SD rats were equally randomized into four groups control group, low fluorosis group, middle fluorosis group, and high fluorosis group. Rats in all three fluorosis groups were fed with corn dried by burning coal obtained from endemic fluorosis areas with high fluoride, and thus the animal models of fluorosis were established. After 120 and 180 days, all the rats were sacrificed. Testis tissues were stained with hematoxylin eosin and observed under light microscope. The malonaldehyde (MDA) content, superoxide dismutase (SOD) activity, total nitric oxide synthase (TNOS), and inducible nitric oxidase synthase (iNOS) were measured by biochemical methods in the testis tissues. The content of NaF in testis was measured by fluorine selective electrode. RESULTS: The rat fluorosis models were successfully established. The fluoride content in testis was significantly increased in all the fluorosis groups(P<0.01). Testicular structures were damaged in all of fluoride groups. The TNOS, iNOS activities, and MDA content of each fluoride group were significantly higher than that of the control group on day 120 and 180 (P<0.05 or 0.01 ). The TNOS, iNOS activities, and MDA content significantly increased in a dose dependent manner (P<0.05 or 0.01). The SOD activities significantly decreased in all the fluoride groups (P<0.05 or 0.01). CONCLUSIONS: Endemic fluoride poisoning caused by coal burning can cause disorders in the oxidative system and antioxidative system in rat testis. The oxidative stress may play an important role in the fluorides induced reproductive toxicity in male rats.