Increasing evidences suggest that circular RNAs (circRNAs) exert crucial functions in regulating gene expression. In this study, we perform RNA-seq and identify 6,154 distinct circRNAs from human bladder cancer and normal bladder tissues. We find that hundreds of circRNAs are significantly dysregulated in human bladder cancer tissues. We further show that circHIPK3, also named bladder cancer-related circular RNA-2 (BCRC-2), is significantly down-regulated in bladder cancer tissues and cell lines, and negatively correlates with bladder cancer grade, invasion as well as lymph node metastasis, respectively. Over-expression of circHIPK3 effectively inhibits migration, invasion, and angiogenesis of bladder cancer cells and suppresses bladder cancer growth and metastasis Mechanistic studies reveal that circHIPK3 contains two critical binding sites for the microRNA miR-558 and can abundantly sponge miR-558 to suppress the expression of heparanase (HPSE). Taken together, our findings provide evidence that circRNAs act as "microRNA sponges", and suggest a new therapeutic target for the treatment of bladder cancer.

Objective: To describe detection of severe acute respiratory syndrome (SARS)-coronavirus 2 (CoV-2) in seminal fluid of patients recovering from coronavirus disease 2019 (COVID-19) and to describe the expression profile of angiotensin-converting enzyme 2 (ACE2) and Transmembrane Serine Protease 2 (TMPRSS2) within the testicle. Design: Observational, cross-sectional study. Setting: Tertiary referral center. Patient(s): Thirty-four adult Chinese males diagnosed with COVID-19 through confirmatory quantitative reverse transcriptasepolymerase chain reaction (qRT-PCR) from pharyngeal swab samples. Intervention(s): None. Main Outcome Measure(s): Identification of SARS-CoV-2 on qRT-PCR of single ejaculated semen samples. Semen quality was not assessed. Expression patterns of ACE2 and TMPRSS2 in the human testis are explored through previously published single-cell transcriptome datasets. Result(s): Six patients (19%) demonstrated scrotal discomfort suggestive of viral orchitis around the time of COVID-19 confirmation. Severe acute respiratory syndrome-CoV-2 was not detected in semen after a median of 31 days (interquartile range, 29-36 days) from COVID-19 diagnosis. Single-cell transcriptome analysis demonstrates sparse expression of ACE2 and TMPRSS2, with almost no overlapping gene expression. Conclusion(s): Severe acute respiratory syndrome-CoV-2 was not detected in the semen of patients recovering from COVID-19 1 month after COVID-19 diagnosis. Angiotensin-converting enzyme 2-mediated viral entry of SARS-CoV-2 into target host cells is unlikely to occur within the human testicle based on ACE2 and TMPRSS2 expression. The long-term effects of SARS-CoV-2 on male reproductive function remain unknown. (Fertil Steril Ò 2020;113:1135-9. Ó2020 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.

Background The current study aimed to determine the impact of SARS-CoV-2 infection on male fertility. Methods This is a single-center, hospital-based observational study that included autopsied testicular and epididymal specimens of deceased COVID-19 male patients ( n =6) and recruited recovering COVID-19 inpatients ( n =23) with an equal number of age-matched controls, respectively. We performed histopathological examinations on testicular and epididymal specimens, and also performed TUNEL assay and immunohistochemistry. Whereas, we investigated the semen specimen for sperm parameters and immune factors. Findings Autopsied testicular and epididymal specimens of COVID-19 showed the presence of interstitial edema, congestion, red blood cell exudation in testes, and epididymides. Thinning of seminiferous tubules was observed. The number of apoptotic cells within seminiferous tubules was significantly higher in COVID-19 compared to control cases. It also showed an increased concentration of CD3+ and CD68+ in the interstitial cells of testicular tissue and the presence of IgG within seminiferous tubules. Semen from COVID-19 inpatients showed that 39.1% ( n =9) of them have oligozoospermia, and 60.9% ( n =14) showed a significant increase in leucocytes in semen. Decreased sperm concentration, and increased seminal levels of IL-6, TNF-α, and MCP-1 compared to control males were observed. Interpretation Impairment of spermatogenesis was observed in COVID-19 patients, which could be partially explained as a result of an elevated immune response in testis. Additionally, autoimmune orchitis occurred in some COVID-19 patients. Further research on the reversibility of impairment and developing treatment are warranted. Funding This study was supported by Ministry of Science and Technology of China Plan, Hubei Science and Technology Plan, National Key Research and Development Program of China, HUST COVID-19 Rapid Response Call, China and National Natural Science Foundation of China; these funding bodies are public institutions, and they had no role in study conception, design, interpretation of results, and manuscript preparation.